~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/btrfs/volumes.c

Version: ~ [ linux-5.6-rc3 ] ~ [ linux-5.5.6 ] ~ [ linux-5.4.22 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.106 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.171 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.214 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.214 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.82 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Copyright (C) 2007 Oracle.  All rights reserved.
  3  *
  4  * This program is free software; you can redistribute it and/or
  5  * modify it under the terms of the GNU General Public
  6  * License v2 as published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful,
  9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 11  * General Public License for more details.
 12  *
 13  * You should have received a copy of the GNU General Public
 14  * License along with this program; if not, write to the
 15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 16  * Boston, MA 021110-1307, USA.
 17  */
 18 #include <linux/sched.h>
 19 #include <linux/bio.h>
 20 #include <linux/slab.h>
 21 #include <linux/buffer_head.h>
 22 #include <linux/blkdev.h>
 23 #include <linux/random.h>
 24 #include <linux/iocontext.h>
 25 #include <linux/capability.h>
 26 #include <linux/ratelimit.h>
 27 #include <linux/kthread.h>
 28 #include <linux/raid/pq.h>
 29 #include <linux/semaphore.h>
 30 #include <asm/div64.h>
 31 #include "ctree.h"
 32 #include "extent_map.h"
 33 #include "disk-io.h"
 34 #include "transaction.h"
 35 #include "print-tree.h"
 36 #include "volumes.h"
 37 #include "raid56.h"
 38 #include "async-thread.h"
 39 #include "check-integrity.h"
 40 #include "rcu-string.h"
 41 #include "math.h"
 42 #include "dev-replace.h"
 43 
 44 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 45                                 struct btrfs_root *root,
 46                                 struct btrfs_device *device);
 47 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
 48 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
 49 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev);
 50 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
 51 
 52 static DEFINE_MUTEX(uuid_mutex);
 53 static LIST_HEAD(fs_uuids);
 54 
 55 static void lock_chunks(struct btrfs_root *root)
 56 {
 57         mutex_lock(&root->fs_info->chunk_mutex);
 58 }
 59 
 60 static void unlock_chunks(struct btrfs_root *root)
 61 {
 62         mutex_unlock(&root->fs_info->chunk_mutex);
 63 }
 64 
 65 static struct btrfs_fs_devices *__alloc_fs_devices(void)
 66 {
 67         struct btrfs_fs_devices *fs_devs;
 68 
 69         fs_devs = kzalloc(sizeof(*fs_devs), GFP_NOFS);
 70         if (!fs_devs)
 71                 return ERR_PTR(-ENOMEM);
 72 
 73         mutex_init(&fs_devs->device_list_mutex);
 74 
 75         INIT_LIST_HEAD(&fs_devs->devices);
 76         INIT_LIST_HEAD(&fs_devs->alloc_list);
 77         INIT_LIST_HEAD(&fs_devs->list);
 78 
 79         return fs_devs;
 80 }
 81 
 82 /**
 83  * alloc_fs_devices - allocate struct btrfs_fs_devices
 84  * @fsid:       a pointer to UUID for this FS.  If NULL a new UUID is
 85  *              generated.
 86  *
 87  * Return: a pointer to a new &struct btrfs_fs_devices on success;
 88  * ERR_PTR() on error.  Returned struct is not linked onto any lists and
 89  * can be destroyed with kfree() right away.
 90  */
 91 static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid)
 92 {
 93         struct btrfs_fs_devices *fs_devs;
 94 
 95         fs_devs = __alloc_fs_devices();
 96         if (IS_ERR(fs_devs))
 97                 return fs_devs;
 98 
 99         if (fsid)
100                 memcpy(fs_devs->fsid, fsid, BTRFS_FSID_SIZE);
101         else
102                 generate_random_uuid(fs_devs->fsid);
103 
104         return fs_devs;
105 }
106 
107 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
108 {
109         struct btrfs_device *device;
110         WARN_ON(fs_devices->opened);
111         while (!list_empty(&fs_devices->devices)) {
112                 device = list_entry(fs_devices->devices.next,
113                                     struct btrfs_device, dev_list);
114                 list_del(&device->dev_list);
115                 rcu_string_free(device->name);
116                 kfree(device);
117         }
118         kfree(fs_devices);
119 }
120 
121 static void btrfs_kobject_uevent(struct block_device *bdev,
122                                  enum kobject_action action)
123 {
124         int ret;
125 
126         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
127         if (ret)
128                 pr_warn("Sending event '%d' to kobject: '%s' (%p): failed\n",
129                         action,
130                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
131                         &disk_to_dev(bdev->bd_disk)->kobj);
132 }
133 
134 void btrfs_cleanup_fs_uuids(void)
135 {
136         struct btrfs_fs_devices *fs_devices;
137 
138         while (!list_empty(&fs_uuids)) {
139                 fs_devices = list_entry(fs_uuids.next,
140                                         struct btrfs_fs_devices, list);
141                 list_del(&fs_devices->list);
142                 free_fs_devices(fs_devices);
143         }
144 }
145 
146 static struct btrfs_device *__alloc_device(void)
147 {
148         struct btrfs_device *dev;
149 
150         dev = kzalloc(sizeof(*dev), GFP_NOFS);
151         if (!dev)
152                 return ERR_PTR(-ENOMEM);
153 
154         INIT_LIST_HEAD(&dev->dev_list);
155         INIT_LIST_HEAD(&dev->dev_alloc_list);
156 
157         spin_lock_init(&dev->io_lock);
158 
159         spin_lock_init(&dev->reada_lock);
160         atomic_set(&dev->reada_in_flight, 0);
161         INIT_RADIX_TREE(&dev->reada_zones, GFP_NOFS & ~__GFP_WAIT);
162         INIT_RADIX_TREE(&dev->reada_extents, GFP_NOFS & ~__GFP_WAIT);
163 
164         return dev;
165 }
166 
167 static noinline struct btrfs_device *__find_device(struct list_head *head,
168                                                    u64 devid, u8 *uuid)
169 {
170         struct btrfs_device *dev;
171 
172         list_for_each_entry(dev, head, dev_list) {
173                 if (dev->devid == devid &&
174                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
175                         return dev;
176                 }
177         }
178         return NULL;
179 }
180 
181 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
182 {
183         struct btrfs_fs_devices *fs_devices;
184 
185         list_for_each_entry(fs_devices, &fs_uuids, list) {
186                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
187                         return fs_devices;
188         }
189         return NULL;
190 }
191 
192 static int
193 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
194                       int flush, struct block_device **bdev,
195                       struct buffer_head **bh)
196 {
197         int ret;
198 
199         *bdev = blkdev_get_by_path(device_path, flags, holder);
200 
201         if (IS_ERR(*bdev)) {
202                 ret = PTR_ERR(*bdev);
203                 printk(KERN_INFO "btrfs: open %s failed\n", device_path);
204                 goto error;
205         }
206 
207         if (flush)
208                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
209         ret = set_blocksize(*bdev, 4096);
210         if (ret) {
211                 blkdev_put(*bdev, flags);
212                 goto error;
213         }
214         invalidate_bdev(*bdev);
215         *bh = btrfs_read_dev_super(*bdev);
216         if (!*bh) {
217                 ret = -EINVAL;
218                 blkdev_put(*bdev, flags);
219                 goto error;
220         }
221 
222         return 0;
223 
224 error:
225         *bdev = NULL;
226         *bh = NULL;
227         return ret;
228 }
229 
230 static void requeue_list(struct btrfs_pending_bios *pending_bios,
231                         struct bio *head, struct bio *tail)
232 {
233 
234         struct bio *old_head;
235 
236         old_head = pending_bios->head;
237         pending_bios->head = head;
238         if (pending_bios->tail)
239                 tail->bi_next = old_head;
240         else
241                 pending_bios->tail = tail;
242 }
243 
244 /*
245  * we try to collect pending bios for a device so we don't get a large
246  * number of procs sending bios down to the same device.  This greatly
247  * improves the schedulers ability to collect and merge the bios.
248  *
249  * But, it also turns into a long list of bios to process and that is sure
250  * to eventually make the worker thread block.  The solution here is to
251  * make some progress and then put this work struct back at the end of
252  * the list if the block device is congested.  This way, multiple devices
253  * can make progress from a single worker thread.
254  */
255 static noinline void run_scheduled_bios(struct btrfs_device *device)
256 {
257         struct bio *pending;
258         struct backing_dev_info *bdi;
259         struct btrfs_fs_info *fs_info;
260         struct btrfs_pending_bios *pending_bios;
261         struct bio *tail;
262         struct bio *cur;
263         int again = 0;
264         unsigned long num_run;
265         unsigned long batch_run = 0;
266         unsigned long limit;
267         unsigned long last_waited = 0;
268         int force_reg = 0;
269         int sync_pending = 0;
270         struct blk_plug plug;
271 
272         /*
273          * this function runs all the bios we've collected for
274          * a particular device.  We don't want to wander off to
275          * another device without first sending all of these down.
276          * So, setup a plug here and finish it off before we return
277          */
278         blk_start_plug(&plug);
279 
280         bdi = blk_get_backing_dev_info(device->bdev);
281         fs_info = device->dev_root->fs_info;
282         limit = btrfs_async_submit_limit(fs_info);
283         limit = limit * 2 / 3;
284 
285 loop:
286         spin_lock(&device->io_lock);
287 
288 loop_lock:
289         num_run = 0;
290 
291         /* take all the bios off the list at once and process them
292          * later on (without the lock held).  But, remember the
293          * tail and other pointers so the bios can be properly reinserted
294          * into the list if we hit congestion
295          */
296         if (!force_reg && device->pending_sync_bios.head) {
297                 pending_bios = &device->pending_sync_bios;
298                 force_reg = 1;
299         } else {
300                 pending_bios = &device->pending_bios;
301                 force_reg = 0;
302         }
303 
304         pending = pending_bios->head;
305         tail = pending_bios->tail;
306         WARN_ON(pending && !tail);
307 
308         /*
309          * if pending was null this time around, no bios need processing
310          * at all and we can stop.  Otherwise it'll loop back up again
311          * and do an additional check so no bios are missed.
312          *
313          * device->running_pending is used to synchronize with the
314          * schedule_bio code.
315          */
316         if (device->pending_sync_bios.head == NULL &&
317             device->pending_bios.head == NULL) {
318                 again = 0;
319                 device->running_pending = 0;
320         } else {
321                 again = 1;
322                 device->running_pending = 1;
323         }
324 
325         pending_bios->head = NULL;
326         pending_bios->tail = NULL;
327 
328         spin_unlock(&device->io_lock);
329 
330         while (pending) {
331 
332                 rmb();
333                 /* we want to work on both lists, but do more bios on the
334                  * sync list than the regular list
335                  */
336                 if ((num_run > 32 &&
337                     pending_bios != &device->pending_sync_bios &&
338                     device->pending_sync_bios.head) ||
339                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
340                     device->pending_bios.head)) {
341                         spin_lock(&device->io_lock);
342                         requeue_list(pending_bios, pending, tail);
343                         goto loop_lock;
344                 }
345 
346                 cur = pending;
347                 pending = pending->bi_next;
348                 cur->bi_next = NULL;
349 
350                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
351                     waitqueue_active(&fs_info->async_submit_wait))
352                         wake_up(&fs_info->async_submit_wait);
353 
354                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
355 
356                 /*
357                  * if we're doing the sync list, record that our
358                  * plug has some sync requests on it
359                  *
360                  * If we're doing the regular list and there are
361                  * sync requests sitting around, unplug before
362                  * we add more
363                  */
364                 if (pending_bios == &device->pending_sync_bios) {
365                         sync_pending = 1;
366                 } else if (sync_pending) {
367                         blk_finish_plug(&plug);
368                         blk_start_plug(&plug);
369                         sync_pending = 0;
370                 }
371 
372                 btrfsic_submit_bio(cur->bi_rw, cur);
373                 num_run++;
374                 batch_run++;
375                 if (need_resched())
376                         cond_resched();
377 
378                 /*
379                  * we made progress, there is more work to do and the bdi
380                  * is now congested.  Back off and let other work structs
381                  * run instead
382                  */
383                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
384                     fs_info->fs_devices->open_devices > 1) {
385                         struct io_context *ioc;
386 
387                         ioc = current->io_context;
388 
389                         /*
390                          * the main goal here is that we don't want to
391                          * block if we're going to be able to submit
392                          * more requests without blocking.
393                          *
394                          * This code does two great things, it pokes into
395                          * the elevator code from a filesystem _and_
396                          * it makes assumptions about how batching works.
397                          */
398                         if (ioc && ioc->nr_batch_requests > 0 &&
399                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
400                             (last_waited == 0 ||
401                              ioc->last_waited == last_waited)) {
402                                 /*
403                                  * we want to go through our batch of
404                                  * requests and stop.  So, we copy out
405                                  * the ioc->last_waited time and test
406                                  * against it before looping
407                                  */
408                                 last_waited = ioc->last_waited;
409                                 if (need_resched())
410                                         cond_resched();
411                                 continue;
412                         }
413                         spin_lock(&device->io_lock);
414                         requeue_list(pending_bios, pending, tail);
415                         device->running_pending = 1;
416 
417                         spin_unlock(&device->io_lock);
418                         btrfs_requeue_work(&device->work);
419                         goto done;
420                 }
421                 /* unplug every 64 requests just for good measure */
422                 if (batch_run % 64 == 0) {
423                         blk_finish_plug(&plug);
424                         blk_start_plug(&plug);
425                         sync_pending = 0;
426                 }
427         }
428 
429         cond_resched();
430         if (again)
431                 goto loop;
432 
433         spin_lock(&device->io_lock);
434         if (device->pending_bios.head || device->pending_sync_bios.head)
435                 goto loop_lock;
436         spin_unlock(&device->io_lock);
437 
438 done:
439         blk_finish_plug(&plug);
440 }
441 
442 static void pending_bios_fn(struct btrfs_work *work)
443 {
444         struct btrfs_device *device;
445 
446         device = container_of(work, struct btrfs_device, work);
447         run_scheduled_bios(device);
448 }
449 
450 static noinline int device_list_add(const char *path,
451                            struct btrfs_super_block *disk_super,
452                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
453 {
454         struct btrfs_device *device;
455         struct btrfs_fs_devices *fs_devices;
456         struct rcu_string *name;
457         u64 found_transid = btrfs_super_generation(disk_super);
458 
459         fs_devices = find_fsid(disk_super->fsid);
460         if (!fs_devices) {
461                 fs_devices = alloc_fs_devices(disk_super->fsid);
462                 if (IS_ERR(fs_devices))
463                         return PTR_ERR(fs_devices);
464 
465                 list_add(&fs_devices->list, &fs_uuids);
466                 fs_devices->latest_devid = devid;
467                 fs_devices->latest_trans = found_transid;
468 
469                 device = NULL;
470         } else {
471                 device = __find_device(&fs_devices->devices, devid,
472                                        disk_super->dev_item.uuid);
473         }
474         if (!device) {
475                 if (fs_devices->opened)
476                         return -EBUSY;
477 
478                 device = btrfs_alloc_device(NULL, &devid,
479                                             disk_super->dev_item.uuid);
480                 if (IS_ERR(device)) {
481                         /* we can safely leave the fs_devices entry around */
482                         return PTR_ERR(device);
483                 }
484 
485                 name = rcu_string_strdup(path, GFP_NOFS);
486                 if (!name) {
487                         kfree(device);
488                         return -ENOMEM;
489                 }
490                 rcu_assign_pointer(device->name, name);
491 
492                 mutex_lock(&fs_devices->device_list_mutex);
493                 list_add_rcu(&device->dev_list, &fs_devices->devices);
494                 fs_devices->num_devices++;
495                 mutex_unlock(&fs_devices->device_list_mutex);
496 
497                 device->fs_devices = fs_devices;
498         } else if (!device->name || strcmp(device->name->str, path)) {
499                 name = rcu_string_strdup(path, GFP_NOFS);
500                 if (!name)
501                         return -ENOMEM;
502                 rcu_string_free(device->name);
503                 rcu_assign_pointer(device->name, name);
504                 if (device->missing) {
505                         fs_devices->missing_devices--;
506                         device->missing = 0;
507                 }
508         }
509 
510         if (found_transid > fs_devices->latest_trans) {
511                 fs_devices->latest_devid = devid;
512                 fs_devices->latest_trans = found_transid;
513         }
514         *fs_devices_ret = fs_devices;
515         return 0;
516 }
517 
518 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
519 {
520         struct btrfs_fs_devices *fs_devices;
521         struct btrfs_device *device;
522         struct btrfs_device *orig_dev;
523 
524         fs_devices = alloc_fs_devices(orig->fsid);
525         if (IS_ERR(fs_devices))
526                 return fs_devices;
527 
528         fs_devices->latest_devid = orig->latest_devid;
529         fs_devices->latest_trans = orig->latest_trans;
530         fs_devices->total_devices = orig->total_devices;
531 
532         /* We have held the volume lock, it is safe to get the devices. */
533         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
534                 struct rcu_string *name;
535 
536                 device = btrfs_alloc_device(NULL, &orig_dev->devid,
537                                             orig_dev->uuid);
538                 if (IS_ERR(device))
539                         goto error;
540 
541                 /*
542                  * This is ok to do without rcu read locked because we hold the
543                  * uuid mutex so nothing we touch in here is going to disappear.
544                  */
545                 name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
546                 if (!name) {
547                         kfree(device);
548                         goto error;
549                 }
550                 rcu_assign_pointer(device->name, name);
551 
552                 list_add(&device->dev_list, &fs_devices->devices);
553                 device->fs_devices = fs_devices;
554                 fs_devices->num_devices++;
555         }
556         return fs_devices;
557 error:
558         free_fs_devices(fs_devices);
559         return ERR_PTR(-ENOMEM);
560 }
561 
562 void btrfs_close_extra_devices(struct btrfs_fs_info *fs_info,
563                                struct btrfs_fs_devices *fs_devices, int step)
564 {
565         struct btrfs_device *device, *next;
566 
567         struct block_device *latest_bdev = NULL;
568         u64 latest_devid = 0;
569         u64 latest_transid = 0;
570 
571         mutex_lock(&uuid_mutex);
572 again:
573         /* This is the initialized path, it is safe to release the devices. */
574         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
575                 if (device->in_fs_metadata) {
576                         if (!device->is_tgtdev_for_dev_replace &&
577                             (!latest_transid ||
578                              device->generation > latest_transid)) {
579                                 latest_devid = device->devid;
580                                 latest_transid = device->generation;
581                                 latest_bdev = device->bdev;
582                         }
583                         continue;
584                 }
585 
586                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
587                         /*
588                          * In the first step, keep the device which has
589                          * the correct fsid and the devid that is used
590                          * for the dev_replace procedure.
591                          * In the second step, the dev_replace state is
592                          * read from the device tree and it is known
593                          * whether the procedure is really active or
594                          * not, which means whether this device is
595                          * used or whether it should be removed.
596                          */
597                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
598                                 continue;
599                         }
600                 }
601                 if (device->bdev) {
602                         blkdev_put(device->bdev, device->mode);
603                         device->bdev = NULL;
604                         fs_devices->open_devices--;
605                 }
606                 if (device->writeable) {
607                         list_del_init(&device->dev_alloc_list);
608                         device->writeable = 0;
609                         if (!device->is_tgtdev_for_dev_replace)
610                                 fs_devices->rw_devices--;
611                 }
612                 list_del_init(&device->dev_list);
613                 fs_devices->num_devices--;
614                 rcu_string_free(device->name);
615                 kfree(device);
616         }
617 
618         if (fs_devices->seed) {
619                 fs_devices = fs_devices->seed;
620                 goto again;
621         }
622 
623         fs_devices->latest_bdev = latest_bdev;
624         fs_devices->latest_devid = latest_devid;
625         fs_devices->latest_trans = latest_transid;
626 
627         mutex_unlock(&uuid_mutex);
628 }
629 
630 static void __free_device(struct work_struct *work)
631 {
632         struct btrfs_device *device;
633 
634         device = container_of(work, struct btrfs_device, rcu_work);
635 
636         if (device->bdev)
637                 blkdev_put(device->bdev, device->mode);
638 
639         rcu_string_free(device->name);
640         kfree(device);
641 }
642 
643 static void free_device(struct rcu_head *head)
644 {
645         struct btrfs_device *device;
646 
647         device = container_of(head, struct btrfs_device, rcu);
648 
649         INIT_WORK(&device->rcu_work, __free_device);
650         schedule_work(&device->rcu_work);
651 }
652 
653 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
654 {
655         struct btrfs_device *device;
656 
657         if (--fs_devices->opened > 0)
658                 return 0;
659 
660         mutex_lock(&fs_devices->device_list_mutex);
661         list_for_each_entry(device, &fs_devices->devices, dev_list) {
662                 struct btrfs_device *new_device;
663                 struct rcu_string *name;
664 
665                 if (device->bdev)
666                         fs_devices->open_devices--;
667 
668                 if (device->writeable &&
669                     device->devid != BTRFS_DEV_REPLACE_DEVID) {
670                         list_del_init(&device->dev_alloc_list);
671                         fs_devices->rw_devices--;
672                 }
673 
674                 if (device->can_discard)
675                         fs_devices->num_can_discard--;
676                 if (device->missing)
677                         fs_devices->missing_devices--;
678 
679                 new_device = btrfs_alloc_device(NULL, &device->devid,
680                                                 device->uuid);
681                 BUG_ON(IS_ERR(new_device)); /* -ENOMEM */
682 
683                 /* Safe because we are under uuid_mutex */
684                 if (device->name) {
685                         name = rcu_string_strdup(device->name->str, GFP_NOFS);
686                         BUG_ON(!name); /* -ENOMEM */
687                         rcu_assign_pointer(new_device->name, name);
688                 }
689 
690                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
691                 new_device->fs_devices = device->fs_devices;
692 
693                 call_rcu(&device->rcu, free_device);
694         }
695         mutex_unlock(&fs_devices->device_list_mutex);
696 
697         WARN_ON(fs_devices->open_devices);
698         WARN_ON(fs_devices->rw_devices);
699         fs_devices->opened = 0;
700         fs_devices->seeding = 0;
701 
702         return 0;
703 }
704 
705 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
706 {
707         struct btrfs_fs_devices *seed_devices = NULL;
708         int ret;
709 
710         mutex_lock(&uuid_mutex);
711         ret = __btrfs_close_devices(fs_devices);
712         if (!fs_devices->opened) {
713                 seed_devices = fs_devices->seed;
714                 fs_devices->seed = NULL;
715         }
716         mutex_unlock(&uuid_mutex);
717 
718         while (seed_devices) {
719                 fs_devices = seed_devices;
720                 seed_devices = fs_devices->seed;
721                 __btrfs_close_devices(fs_devices);
722                 free_fs_devices(fs_devices);
723         }
724         /*
725          * Wait for rcu kworkers under __btrfs_close_devices
726          * to finish all blkdev_puts so device is really
727          * free when umount is done.
728          */
729         rcu_barrier();
730         return ret;
731 }
732 
733 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
734                                 fmode_t flags, void *holder)
735 {
736         struct request_queue *q;
737         struct block_device *bdev;
738         struct list_head *head = &fs_devices->devices;
739         struct btrfs_device *device;
740         struct block_device *latest_bdev = NULL;
741         struct buffer_head *bh;
742         struct btrfs_super_block *disk_super;
743         u64 latest_devid = 0;
744         u64 latest_transid = 0;
745         u64 devid;
746         int seeding = 1;
747         int ret = 0;
748 
749         flags |= FMODE_EXCL;
750 
751         list_for_each_entry(device, head, dev_list) {
752                 if (device->bdev)
753                         continue;
754                 if (!device->name)
755                         continue;
756 
757                 /* Just open everything we can; ignore failures here */
758                 if (btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
759                                             &bdev, &bh))
760                         continue;
761 
762                 disk_super = (struct btrfs_super_block *)bh->b_data;
763                 devid = btrfs_stack_device_id(&disk_super->dev_item);
764                 if (devid != device->devid)
765                         goto error_brelse;
766 
767                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
768                            BTRFS_UUID_SIZE))
769                         goto error_brelse;
770 
771                 device->generation = btrfs_super_generation(disk_super);
772                 if (!latest_transid || device->generation > latest_transid) {
773                         latest_devid = devid;
774                         latest_transid = device->generation;
775                         latest_bdev = bdev;
776                 }
777 
778                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
779                         device->writeable = 0;
780                 } else {
781                         device->writeable = !bdev_read_only(bdev);
782                         seeding = 0;
783                 }
784 
785                 q = bdev_get_queue(bdev);
786                 if (blk_queue_discard(q)) {
787                         device->can_discard = 1;
788                         fs_devices->num_can_discard++;
789                 }
790 
791                 device->bdev = bdev;
792                 device->in_fs_metadata = 0;
793                 device->mode = flags;
794 
795                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
796                         fs_devices->rotating = 1;
797 
798                 fs_devices->open_devices++;
799                 if (device->writeable &&
800                     device->devid != BTRFS_DEV_REPLACE_DEVID) {
801                         fs_devices->rw_devices++;
802                         list_add(&device->dev_alloc_list,
803                                  &fs_devices->alloc_list);
804                 }
805                 brelse(bh);
806                 continue;
807 
808 error_brelse:
809                 brelse(bh);
810                 blkdev_put(bdev, flags);
811                 continue;
812         }
813         if (fs_devices->open_devices == 0) {
814                 ret = -EINVAL;
815                 goto out;
816         }
817         fs_devices->seeding = seeding;
818         fs_devices->opened = 1;
819         fs_devices->latest_bdev = latest_bdev;
820         fs_devices->latest_devid = latest_devid;
821         fs_devices->latest_trans = latest_transid;
822         fs_devices->total_rw_bytes = 0;
823 out:
824         return ret;
825 }
826 
827 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
828                        fmode_t flags, void *holder)
829 {
830         int ret;
831 
832         mutex_lock(&uuid_mutex);
833         if (fs_devices->opened) {
834                 fs_devices->opened++;
835                 ret = 0;
836         } else {
837                 ret = __btrfs_open_devices(fs_devices, flags, holder);
838         }
839         mutex_unlock(&uuid_mutex);
840         return ret;
841 }
842 
843 /*
844  * Look for a btrfs signature on a device. This may be called out of the mount path
845  * and we are not allowed to call set_blocksize during the scan. The superblock
846  * is read via pagecache
847  */
848 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
849                           struct btrfs_fs_devices **fs_devices_ret)
850 {
851         struct btrfs_super_block *disk_super;
852         struct block_device *bdev;
853         struct page *page;
854         void *p;
855         int ret = -EINVAL;
856         u64 devid;
857         u64 transid;
858         u64 total_devices;
859         u64 bytenr;
860         pgoff_t index;
861 
862         /*
863          * we would like to check all the supers, but that would make
864          * a btrfs mount succeed after a mkfs from a different FS.
865          * So, we need to add a special mount option to scan for
866          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
867          */
868         bytenr = btrfs_sb_offset(0);
869         flags |= FMODE_EXCL;
870         mutex_lock(&uuid_mutex);
871 
872         bdev = blkdev_get_by_path(path, flags, holder);
873 
874         if (IS_ERR(bdev)) {
875                 ret = PTR_ERR(bdev);
876                 goto error;
877         }
878 
879         /* make sure our super fits in the device */
880         if (bytenr + PAGE_CACHE_SIZE >= i_size_read(bdev->bd_inode))
881                 goto error_bdev_put;
882 
883         /* make sure our super fits in the page */
884         if (sizeof(*disk_super) > PAGE_CACHE_SIZE)
885                 goto error_bdev_put;
886 
887         /* make sure our super doesn't straddle pages on disk */
888         index = bytenr >> PAGE_CACHE_SHIFT;
889         if ((bytenr + sizeof(*disk_super) - 1) >> PAGE_CACHE_SHIFT != index)
890                 goto error_bdev_put;
891 
892         /* pull in the page with our super */
893         page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
894                                    index, GFP_NOFS);
895 
896         if (IS_ERR_OR_NULL(page))
897                 goto error_bdev_put;
898 
899         p = kmap(page);
900 
901         /* align our pointer to the offset of the super block */
902         disk_super = p + (bytenr & ~PAGE_CACHE_MASK);
903 
904         if (btrfs_super_bytenr(disk_super) != bytenr ||
905             btrfs_super_magic(disk_super) != BTRFS_MAGIC)
906                 goto error_unmap;
907 
908         devid = btrfs_stack_device_id(&disk_super->dev_item);
909         transid = btrfs_super_generation(disk_super);
910         total_devices = btrfs_super_num_devices(disk_super);
911 
912         if (disk_super->label[0]) {
913                 if (disk_super->label[BTRFS_LABEL_SIZE - 1])
914                         disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
915                 printk(KERN_INFO "btrfs: device label %s ", disk_super->label);
916         } else {
917                 printk(KERN_INFO "btrfs: device fsid %pU ", disk_super->fsid);
918         }
919 
920         printk(KERN_CONT "devid %llu transid %llu %s\n", devid, transid, path);
921 
922         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
923         if (!ret && fs_devices_ret)
924                 (*fs_devices_ret)->total_devices = total_devices;
925 
926 error_unmap:
927         kunmap(page);
928         page_cache_release(page);
929 
930 error_bdev_put:
931         blkdev_put(bdev, flags);
932 error:
933         mutex_unlock(&uuid_mutex);
934         return ret;
935 }
936 
937 /* helper to account the used device space in the range */
938 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
939                                    u64 end, u64 *length)
940 {
941         struct btrfs_key key;
942         struct btrfs_root *root = device->dev_root;
943         struct btrfs_dev_extent *dev_extent;
944         struct btrfs_path *path;
945         u64 extent_end;
946         int ret;
947         int slot;
948         struct extent_buffer *l;
949 
950         *length = 0;
951 
952         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
953                 return 0;
954 
955         path = btrfs_alloc_path();
956         if (!path)
957                 return -ENOMEM;
958         path->reada = 2;
959 
960         key.objectid = device->devid;
961         key.offset = start;
962         key.type = BTRFS_DEV_EXTENT_KEY;
963 
964         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
965         if (ret < 0)
966                 goto out;
967         if (ret > 0) {
968                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
969                 if (ret < 0)
970                         goto out;
971         }
972 
973         while (1) {
974                 l = path->nodes[0];
975                 slot = path->slots[0];
976                 if (slot >= btrfs_header_nritems(l)) {
977                         ret = btrfs_next_leaf(root, path);
978                         if (ret == 0)
979                                 continue;
980                         if (ret < 0)
981                                 goto out;
982 
983                         break;
984                 }
985                 btrfs_item_key_to_cpu(l, &key, slot);
986 
987                 if (key.objectid < device->devid)
988                         goto next;
989 
990                 if (key.objectid > device->devid)
991                         break;
992 
993                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
994                         goto next;
995 
996                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
997                 extent_end = key.offset + btrfs_dev_extent_length(l,
998                                                                   dev_extent);
999                 if (key.offset <= start && extent_end > end) {
1000                         *length = end - start + 1;
1001                         break;
1002                 } else if (key.offset <= start && extent_end > start)
1003                         *length += extent_end - start;
1004                 else if (key.offset > start && extent_end <= end)
1005                         *length += extent_end - key.offset;
1006                 else if (key.offset > start && key.offset <= end) {
1007                         *length += end - key.offset + 1;
1008                         break;
1009                 } else if (key.offset > end)
1010                         break;
1011 
1012 next:
1013                 path->slots[0]++;
1014         }
1015         ret = 0;
1016 out:
1017         btrfs_free_path(path);
1018         return ret;
1019 }
1020 
1021 static int contains_pending_extent(struct btrfs_trans_handle *trans,
1022                                    struct btrfs_device *device,
1023                                    u64 *start, u64 len)
1024 {
1025         struct extent_map *em;
1026         int ret = 0;
1027 
1028         list_for_each_entry(em, &trans->transaction->pending_chunks, list) {
1029                 struct map_lookup *map;
1030                 int i;
1031 
1032                 map = (struct map_lookup *)em->bdev;
1033                 for (i = 0; i < map->num_stripes; i++) {
1034                         if (map->stripes[i].dev != device)
1035                                 continue;
1036                         if (map->stripes[i].physical >= *start + len ||
1037                             map->stripes[i].physical + em->orig_block_len <=
1038                             *start)
1039                                 continue;
1040                         *start = map->stripes[i].physical +
1041                                 em->orig_block_len;
1042                         ret = 1;
1043                 }
1044         }
1045 
1046         return ret;
1047 }
1048 
1049 
1050 /*
1051  * find_free_dev_extent - find free space in the specified device
1052  * @device:     the device which we search the free space in
1053  * @num_bytes:  the size of the free space that we need
1054  * @start:      store the start of the free space.
1055  * @len:        the size of the free space. that we find, or the size of the max
1056  *              free space if we don't find suitable free space
1057  *
1058  * this uses a pretty simple search, the expectation is that it is
1059  * called very infrequently and that a given device has a small number
1060  * of extents
1061  *
1062  * @start is used to store the start of the free space if we find. But if we
1063  * don't find suitable free space, it will be used to store the start position
1064  * of the max free space.
1065  *
1066  * @len is used to store the size of the free space that we find.
1067  * But if we don't find suitable free space, it is used to store the size of
1068  * the max free space.
1069  */
1070 int find_free_dev_extent(struct btrfs_trans_handle *trans,
1071                          struct btrfs_device *device, u64 num_bytes,
1072                          u64 *start, u64 *len)
1073 {
1074         struct btrfs_key key;
1075         struct btrfs_root *root = device->dev_root;
1076         struct btrfs_dev_extent *dev_extent;
1077         struct btrfs_path *path;
1078         u64 hole_size;
1079         u64 max_hole_start;
1080         u64 max_hole_size;
1081         u64 extent_end;
1082         u64 search_start;
1083         u64 search_end = device->total_bytes;
1084         int ret;
1085         int slot;
1086         struct extent_buffer *l;
1087 
1088         /* FIXME use last free of some kind */
1089 
1090         /* we don't want to overwrite the superblock on the drive,
1091          * so we make sure to start at an offset of at least 1MB
1092          */
1093         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
1094 
1095         path = btrfs_alloc_path();
1096         if (!path)
1097                 return -ENOMEM;
1098 again:
1099         max_hole_start = search_start;
1100         max_hole_size = 0;
1101         hole_size = 0;
1102 
1103         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
1104                 ret = -ENOSPC;
1105                 goto out;
1106         }
1107 
1108         path->reada = 2;
1109         path->search_commit_root = 1;
1110         path->skip_locking = 1;
1111 
1112         key.objectid = device->devid;
1113         key.offset = search_start;
1114         key.type = BTRFS_DEV_EXTENT_KEY;
1115 
1116         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1117         if (ret < 0)
1118                 goto out;
1119         if (ret > 0) {
1120                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1121                 if (ret < 0)
1122                         goto out;
1123         }
1124 
1125         while (1) {
1126                 l = path->nodes[0];
1127                 slot = path->slots[0];
1128                 if (slot >= btrfs_header_nritems(l)) {
1129                         ret = btrfs_next_leaf(root, path);
1130                         if (ret == 0)
1131                                 continue;
1132                         if (ret < 0)
1133                                 goto out;
1134 
1135                         break;
1136                 }
1137                 btrfs_item_key_to_cpu(l, &key, slot);
1138 
1139                 if (key.objectid < device->devid)
1140                         goto next;
1141 
1142                 if (key.objectid > device->devid)
1143                         break;
1144 
1145                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
1146                         goto next;
1147 
1148                 if (key.offset > search_start) {
1149                         hole_size = key.offset - search_start;
1150 
1151                         /*
1152                          * Have to check before we set max_hole_start, otherwise
1153                          * we could end up sending back this offset anyway.
1154                          */
1155                         if (contains_pending_extent(trans, device,
1156                                                     &search_start,
1157                                                     hole_size))
1158                                 hole_size = 0;
1159 
1160                         if (hole_size > max_hole_size) {
1161                                 max_hole_start = search_start;
1162                                 max_hole_size = hole_size;
1163                         }
1164 
1165                         /*
1166                          * If this free space is greater than which we need,
1167                          * it must be the max free space that we have found
1168                          * until now, so max_hole_start must point to the start
1169                          * of this free space and the length of this free space
1170                          * is stored in max_hole_size. Thus, we return
1171                          * max_hole_start and max_hole_size and go back to the
1172                          * caller.
1173                          */
1174                         if (hole_size >= num_bytes) {
1175                                 ret = 0;
1176                                 goto out;
1177                         }
1178                 }
1179 
1180                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1181                 extent_end = key.offset + btrfs_dev_extent_length(l,
1182                                                                   dev_extent);
1183                 if (extent_end > search_start)
1184                         search_start = extent_end;
1185 next:
1186                 path->slots[0]++;
1187                 cond_resched();
1188         }
1189 
1190         /*
1191          * At this point, search_start should be the end of
1192          * allocated dev extents, and when shrinking the device,
1193          * search_end may be smaller than search_start.
1194          */
1195         if (search_end > search_start)
1196                 hole_size = search_end - search_start;
1197 
1198         if (hole_size > max_hole_size) {
1199                 max_hole_start = search_start;
1200                 max_hole_size = hole_size;
1201         }
1202 
1203         if (contains_pending_extent(trans, device, &search_start, hole_size)) {
1204                 btrfs_release_path(path);
1205                 goto again;
1206         }
1207 
1208         /* See above. */
1209         if (hole_size < num_bytes)
1210                 ret = -ENOSPC;
1211         else
1212                 ret = 0;
1213 
1214 out:
1215         btrfs_free_path(path);
1216         *start = max_hole_start;
1217         if (len)
1218                 *len = max_hole_size;
1219         return ret;
1220 }
1221 
1222 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1223                           struct btrfs_device *device,
1224                           u64 start)
1225 {
1226         int ret;
1227         struct btrfs_path *path;
1228         struct btrfs_root *root = device->dev_root;
1229         struct btrfs_key key;
1230         struct btrfs_key found_key;
1231         struct extent_buffer *leaf = NULL;
1232         struct btrfs_dev_extent *extent = NULL;
1233 
1234         path = btrfs_alloc_path();
1235         if (!path)
1236                 return -ENOMEM;
1237 
1238         key.objectid = device->devid;
1239         key.offset = start;
1240         key.type = BTRFS_DEV_EXTENT_KEY;
1241 again:
1242         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1243         if (ret > 0) {
1244                 ret = btrfs_previous_item(root, path, key.objectid,
1245                                           BTRFS_DEV_EXTENT_KEY);
1246                 if (ret)
1247                         goto out;
1248                 leaf = path->nodes[0];
1249                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1250                 extent = btrfs_item_ptr(leaf, path->slots[0],
1251                                         struct btrfs_dev_extent);
1252                 BUG_ON(found_key.offset > start || found_key.offset +
1253                        btrfs_dev_extent_length(leaf, extent) < start);
1254                 key = found_key;
1255                 btrfs_release_path(path);
1256                 goto again;
1257         } else if (ret == 0) {
1258                 leaf = path->nodes[0];
1259                 extent = btrfs_item_ptr(leaf, path->slots[0],
1260                                         struct btrfs_dev_extent);
1261         } else {
1262                 btrfs_error(root->fs_info, ret, "Slot search failed");
1263                 goto out;
1264         }
1265 
1266         if (device->bytes_used > 0) {
1267                 u64 len = btrfs_dev_extent_length(leaf, extent);
1268                 device->bytes_used -= len;
1269                 spin_lock(&root->fs_info->free_chunk_lock);
1270                 root->fs_info->free_chunk_space += len;
1271                 spin_unlock(&root->fs_info->free_chunk_lock);
1272         }
1273         ret = btrfs_del_item(trans, root, path);
1274         if (ret) {
1275                 btrfs_error(root->fs_info, ret,
1276                             "Failed to remove dev extent item");
1277         }
1278 out:
1279         btrfs_free_path(path);
1280         return ret;
1281 }
1282 
1283 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1284                                   struct btrfs_device *device,
1285                                   u64 chunk_tree, u64 chunk_objectid,
1286                                   u64 chunk_offset, u64 start, u64 num_bytes)
1287 {
1288         int ret;
1289         struct btrfs_path *path;
1290         struct btrfs_root *root = device->dev_root;
1291         struct btrfs_dev_extent *extent;
1292         struct extent_buffer *leaf;
1293         struct btrfs_key key;
1294 
1295         WARN_ON(!device->in_fs_metadata);
1296         WARN_ON(device->is_tgtdev_for_dev_replace);
1297         path = btrfs_alloc_path();
1298         if (!path)
1299                 return -ENOMEM;
1300 
1301         key.objectid = device->devid;
1302         key.offset = start;
1303         key.type = BTRFS_DEV_EXTENT_KEY;
1304         ret = btrfs_insert_empty_item(trans, root, path, &key,
1305                                       sizeof(*extent));
1306         if (ret)
1307                 goto out;
1308 
1309         leaf = path->nodes[0];
1310         extent = btrfs_item_ptr(leaf, path->slots[0],
1311                                 struct btrfs_dev_extent);
1312         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1313         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1314         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1315 
1316         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1317                     btrfs_dev_extent_chunk_tree_uuid(extent), BTRFS_UUID_SIZE);
1318 
1319         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1320         btrfs_mark_buffer_dirty(leaf);
1321 out:
1322         btrfs_free_path(path);
1323         return ret;
1324 }
1325 
1326 static u64 find_next_chunk(struct btrfs_fs_info *fs_info)
1327 {
1328         struct extent_map_tree *em_tree;
1329         struct extent_map *em;
1330         struct rb_node *n;
1331         u64 ret = 0;
1332 
1333         em_tree = &fs_info->mapping_tree.map_tree;
1334         read_lock(&em_tree->lock);
1335         n = rb_last(&em_tree->map);
1336         if (n) {
1337                 em = rb_entry(n, struct extent_map, rb_node);
1338                 ret = em->start + em->len;
1339         }
1340         read_unlock(&em_tree->lock);
1341 
1342         return ret;
1343 }
1344 
1345 static noinline int find_next_devid(struct btrfs_fs_info *fs_info,
1346                                     u64 *devid_ret)
1347 {
1348         int ret;
1349         struct btrfs_key key;
1350         struct btrfs_key found_key;
1351         struct btrfs_path *path;
1352 
1353         path = btrfs_alloc_path();
1354         if (!path)
1355                 return -ENOMEM;
1356 
1357         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1358         key.type = BTRFS_DEV_ITEM_KEY;
1359         key.offset = (u64)-1;
1360 
1361         ret = btrfs_search_slot(NULL, fs_info->chunk_root, &key, path, 0, 0);
1362         if (ret < 0)
1363                 goto error;
1364 
1365         BUG_ON(ret == 0); /* Corruption */
1366 
1367         ret = btrfs_previous_item(fs_info->chunk_root, path,
1368                                   BTRFS_DEV_ITEMS_OBJECTID,
1369                                   BTRFS_DEV_ITEM_KEY);
1370         if (ret) {
1371                 *devid_ret = 1;
1372         } else {
1373                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1374                                       path->slots[0]);
1375                 *devid_ret = found_key.offset + 1;
1376         }
1377         ret = 0;
1378 error:
1379         btrfs_free_path(path);
1380         return ret;
1381 }
1382 
1383 /*
1384  * the device information is stored in the chunk root
1385  * the btrfs_device struct should be fully filled in
1386  */
1387 static int btrfs_add_device(struct btrfs_trans_handle *trans,
1388                             struct btrfs_root *root,
1389                             struct btrfs_device *device)
1390 {
1391         int ret;
1392         struct btrfs_path *path;
1393         struct btrfs_dev_item *dev_item;
1394         struct extent_buffer *leaf;
1395         struct btrfs_key key;
1396         unsigned long ptr;
1397 
1398         root = root->fs_info->chunk_root;
1399 
1400         path = btrfs_alloc_path();
1401         if (!path)
1402                 return -ENOMEM;
1403 
1404         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1405         key.type = BTRFS_DEV_ITEM_KEY;
1406         key.offset = device->devid;
1407 
1408         ret = btrfs_insert_empty_item(trans, root, path, &key,
1409                                       sizeof(*dev_item));
1410         if (ret)
1411                 goto out;
1412 
1413         leaf = path->nodes[0];
1414         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1415 
1416         btrfs_set_device_id(leaf, dev_item, device->devid);
1417         btrfs_set_device_generation(leaf, dev_item, 0);
1418         btrfs_set_device_type(leaf, dev_item, device->type);
1419         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1420         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1421         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1422         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1423         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1424         btrfs_set_device_group(leaf, dev_item, 0);
1425         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1426         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1427         btrfs_set_device_start_offset(leaf, dev_item, 0);
1428 
1429         ptr = btrfs_device_uuid(dev_item);
1430         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1431         ptr = btrfs_device_fsid(dev_item);
1432         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1433         btrfs_mark_buffer_dirty(leaf);
1434 
1435         ret = 0;
1436 out:
1437         btrfs_free_path(path);
1438         return ret;
1439 }
1440 
1441 static int btrfs_rm_dev_item(struct btrfs_root *root,
1442                              struct btrfs_device *device)
1443 {
1444         int ret;
1445         struct btrfs_path *path;
1446         struct btrfs_key key;
1447         struct btrfs_trans_handle *trans;
1448 
1449         root = root->fs_info->chunk_root;
1450 
1451         path = btrfs_alloc_path();
1452         if (!path)
1453                 return -ENOMEM;
1454 
1455         trans = btrfs_start_transaction(root, 0);
1456         if (IS_ERR(trans)) {
1457                 btrfs_free_path(path);
1458                 return PTR_ERR(trans);
1459         }
1460         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1461         key.type = BTRFS_DEV_ITEM_KEY;
1462         key.offset = device->devid;
1463         lock_chunks(root);
1464 
1465         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1466         if (ret < 0)
1467                 goto out;
1468 
1469         if (ret > 0) {
1470                 ret = -ENOENT;
1471                 goto out;
1472         }
1473 
1474         ret = btrfs_del_item(trans, root, path);
1475         if (ret)
1476                 goto out;
1477 out:
1478         btrfs_free_path(path);
1479         unlock_chunks(root);
1480         btrfs_commit_transaction(trans, root);
1481         return ret;
1482 }
1483 
1484 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1485 {
1486         struct btrfs_device *device;
1487         struct btrfs_device *next_device;
1488         struct block_device *bdev;
1489         struct buffer_head *bh = NULL;
1490         struct btrfs_super_block *disk_super;
1491         struct btrfs_fs_devices *cur_devices;
1492         u64 all_avail;
1493         u64 devid;
1494         u64 num_devices;
1495         u8 *dev_uuid;
1496         unsigned seq;
1497         int ret = 0;
1498         bool clear_super = false;
1499 
1500         mutex_lock(&uuid_mutex);
1501 
1502         do {
1503                 seq = read_seqbegin(&root->fs_info->profiles_lock);
1504 
1505                 all_avail = root->fs_info->avail_data_alloc_bits |
1506                             root->fs_info->avail_system_alloc_bits |
1507                             root->fs_info->avail_metadata_alloc_bits;
1508         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
1509 
1510         num_devices = root->fs_info->fs_devices->num_devices;
1511         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1512         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1513                 WARN_ON(num_devices < 1);
1514                 num_devices--;
1515         }
1516         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1517 
1518         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1519                 ret = BTRFS_ERROR_DEV_RAID10_MIN_NOT_MET;
1520                 goto out;
1521         }
1522 
1523         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1524                 ret = BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET;
1525                 goto out;
1526         }
1527 
1528         if ((all_avail & BTRFS_BLOCK_GROUP_RAID5) &&
1529             root->fs_info->fs_devices->rw_devices <= 2) {
1530                 ret = BTRFS_ERROR_DEV_RAID5_MIN_NOT_MET;
1531                 goto out;
1532         }
1533         if ((all_avail & BTRFS_BLOCK_GROUP_RAID6) &&
1534             root->fs_info->fs_devices->rw_devices <= 3) {
1535                 ret = BTRFS_ERROR_DEV_RAID6_MIN_NOT_MET;
1536                 goto out;
1537         }
1538 
1539         if (strcmp(device_path, "missing") == 0) {
1540                 struct list_head *devices;
1541                 struct btrfs_device *tmp;
1542 
1543                 device = NULL;
1544                 devices = &root->fs_info->fs_devices->devices;
1545                 /*
1546                  * It is safe to read the devices since the volume_mutex
1547                  * is held.
1548                  */
1549                 list_for_each_entry(tmp, devices, dev_list) {
1550                         if (tmp->in_fs_metadata &&
1551                             !tmp->is_tgtdev_for_dev_replace &&
1552                             !tmp->bdev) {
1553                                 device = tmp;
1554                                 break;
1555                         }
1556                 }
1557                 bdev = NULL;
1558                 bh = NULL;
1559                 disk_super = NULL;
1560                 if (!device) {
1561                         ret = BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
1562                         goto out;
1563                 }
1564         } else {
1565                 ret = btrfs_get_bdev_and_sb(device_path,
1566                                             FMODE_WRITE | FMODE_EXCL,
1567                                             root->fs_info->bdev_holder, 0,
1568                                             &bdev, &bh);
1569                 if (ret)
1570                         goto out;
1571                 disk_super = (struct btrfs_super_block *)bh->b_data;
1572                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1573                 dev_uuid = disk_super->dev_item.uuid;
1574                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1575                                            disk_super->fsid);
1576                 if (!device) {
1577                         ret = -ENOENT;
1578                         goto error_brelse;
1579                 }
1580         }
1581 
1582         if (device->is_tgtdev_for_dev_replace) {
1583                 ret = BTRFS_ERROR_DEV_TGT_REPLACE;
1584                 goto error_brelse;
1585         }
1586 
1587         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1588                 ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
1589                 goto error_brelse;
1590         }
1591 
1592         if (device->writeable) {
1593                 lock_chunks(root);
1594                 list_del_init(&device->dev_alloc_list);
1595                 unlock_chunks(root);
1596                 root->fs_info->fs_devices->rw_devices--;
1597                 clear_super = true;
1598         }
1599 
1600         mutex_unlock(&uuid_mutex);
1601         ret = btrfs_shrink_device(device, 0);
1602         mutex_lock(&uuid_mutex);
1603         if (ret)
1604                 goto error_undo;
1605 
1606         /*
1607          * TODO: the superblock still includes this device in its num_devices
1608          * counter although write_all_supers() is not locked out. This
1609          * could give a filesystem state which requires a degraded mount.
1610          */
1611         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1612         if (ret)
1613                 goto error_undo;
1614 
1615         spin_lock(&root->fs_info->free_chunk_lock);
1616         root->fs_info->free_chunk_space = device->total_bytes -
1617                 device->bytes_used;
1618         spin_unlock(&root->fs_info->free_chunk_lock);
1619 
1620         device->in_fs_metadata = 0;
1621         btrfs_scrub_cancel_dev(root->fs_info, device);
1622 
1623         /*
1624          * the device list mutex makes sure that we don't change
1625          * the device list while someone else is writing out all
1626          * the device supers. Whoever is writing all supers, should
1627          * lock the device list mutex before getting the number of
1628          * devices in the super block (super_copy). Conversely,
1629          * whoever updates the number of devices in the super block
1630          * (super_copy) should hold the device list mutex.
1631          */
1632 
1633         cur_devices = device->fs_devices;
1634         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1635         list_del_rcu(&device->dev_list);
1636 
1637         device->fs_devices->num_devices--;
1638         device->fs_devices->total_devices--;
1639 
1640         if (device->missing)
1641                 root->fs_info->fs_devices->missing_devices--;
1642 
1643         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1644                                  struct btrfs_device, dev_list);
1645         if (device->bdev == root->fs_info->sb->s_bdev)
1646                 root->fs_info->sb->s_bdev = next_device->bdev;
1647         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1648                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1649 
1650         if (device->bdev)
1651                 device->fs_devices->open_devices--;
1652 
1653         call_rcu(&device->rcu, free_device);
1654 
1655         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1656         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1657         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1658 
1659         if (cur_devices->open_devices == 0) {
1660                 struct btrfs_fs_devices *fs_devices;
1661                 fs_devices = root->fs_info->fs_devices;
1662                 while (fs_devices) {
1663                         if (fs_devices->seed == cur_devices)
1664                                 break;
1665                         fs_devices = fs_devices->seed;
1666                 }
1667                 fs_devices->seed = cur_devices->seed;
1668                 cur_devices->seed = NULL;
1669                 lock_chunks(root);
1670                 __btrfs_close_devices(cur_devices);
1671                 unlock_chunks(root);
1672                 free_fs_devices(cur_devices);
1673         }
1674 
1675         root->fs_info->num_tolerated_disk_barrier_failures =
1676                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1677 
1678         /*
1679          * at this point, the device is zero sized.  We want to
1680          * remove it from the devices list and zero out the old super
1681          */
1682         if (clear_super && disk_super) {
1683                 /* make sure this device isn't detected as part of
1684                  * the FS anymore
1685                  */
1686                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1687                 set_buffer_dirty(bh);
1688                 sync_dirty_buffer(bh);
1689         }
1690 
1691         ret = 0;
1692 
1693         /* Notify udev that device has changed */
1694         if (bdev)
1695                 btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1696 
1697 error_brelse:
1698         brelse(bh);
1699         if (bdev)
1700                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1701 out:
1702         mutex_unlock(&uuid_mutex);
1703         return ret;
1704 error_undo:
1705         if (device->writeable) {
1706                 lock_chunks(root);
1707                 list_add(&device->dev_alloc_list,
1708                          &root->fs_info->fs_devices->alloc_list);
1709                 unlock_chunks(root);
1710                 root->fs_info->fs_devices->rw_devices++;
1711         }
1712         goto error_brelse;
1713 }
1714 
1715 void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
1716                                  struct btrfs_device *srcdev)
1717 {
1718         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1719 
1720         list_del_rcu(&srcdev->dev_list);
1721         list_del_rcu(&srcdev->dev_alloc_list);
1722         fs_info->fs_devices->num_devices--;
1723         if (srcdev->missing) {
1724                 fs_info->fs_devices->missing_devices--;
1725                 fs_info->fs_devices->rw_devices++;
1726         }
1727         if (srcdev->can_discard)
1728                 fs_info->fs_devices->num_can_discard--;
1729         if (srcdev->bdev) {
1730                 fs_info->fs_devices->open_devices--;
1731 
1732                 /* zero out the old super */
1733                 btrfs_scratch_superblock(srcdev);
1734         }
1735 
1736         call_rcu(&srcdev->rcu, free_device);
1737 }
1738 
1739 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
1740                                       struct btrfs_device *tgtdev)
1741 {
1742         struct btrfs_device *next_device;
1743 
1744         WARN_ON(!tgtdev);
1745         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1746         if (tgtdev->bdev) {
1747                 btrfs_scratch_superblock(tgtdev);
1748                 fs_info->fs_devices->open_devices--;
1749         }
1750         fs_info->fs_devices->num_devices--;
1751         if (tgtdev->can_discard)
1752                 fs_info->fs_devices->num_can_discard++;
1753 
1754         next_device = list_entry(fs_info->fs_devices->devices.next,
1755                                  struct btrfs_device, dev_list);
1756         if (tgtdev->bdev == fs_info->sb->s_bdev)
1757                 fs_info->sb->s_bdev = next_device->bdev;
1758         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
1759                 fs_info->fs_devices->latest_bdev = next_device->bdev;
1760         list_del_rcu(&tgtdev->dev_list);
1761 
1762         call_rcu(&tgtdev->rcu, free_device);
1763 
1764         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1765 }
1766 
1767 static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
1768                                      struct btrfs_device **device)
1769 {
1770         int ret = 0;
1771         struct btrfs_super_block *disk_super;
1772         u64 devid;
1773         u8 *dev_uuid;
1774         struct block_device *bdev;
1775         struct buffer_head *bh;
1776 
1777         *device = NULL;
1778         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
1779                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
1780         if (ret)
1781                 return ret;
1782         disk_super = (struct btrfs_super_block *)bh->b_data;
1783         devid = btrfs_stack_device_id(&disk_super->dev_item);
1784         dev_uuid = disk_super->dev_item.uuid;
1785         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1786                                     disk_super->fsid);
1787         brelse(bh);
1788         if (!*device)
1789                 ret = -ENOENT;
1790         blkdev_put(bdev, FMODE_READ);
1791         return ret;
1792 }
1793 
1794 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
1795                                          char *device_path,
1796                                          struct btrfs_device **device)
1797 {
1798         *device = NULL;
1799         if (strcmp(device_path, "missing") == 0) {
1800                 struct list_head *devices;
1801                 struct btrfs_device *tmp;
1802 
1803                 devices = &root->fs_info->fs_devices->devices;
1804                 /*
1805                  * It is safe to read the devices since the volume_mutex
1806                  * is held by the caller.
1807                  */
1808                 list_for_each_entry(tmp, devices, dev_list) {
1809                         if (tmp->in_fs_metadata && !tmp->bdev) {
1810                                 *device = tmp;
1811                                 break;
1812                         }
1813                 }
1814 
1815                 if (!*device) {
1816                         pr_err("btrfs: no missing device found\n");
1817                         return -ENOENT;
1818                 }
1819 
1820                 return 0;
1821         } else {
1822                 return btrfs_find_device_by_path(root, device_path, device);
1823         }
1824 }
1825 
1826 /*
1827  * does all the dirty work required for changing file system's UUID.
1828  */
1829 static int btrfs_prepare_sprout(struct btrfs_root *root)
1830 {
1831         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1832         struct btrfs_fs_devices *old_devices;
1833         struct btrfs_fs_devices *seed_devices;
1834         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1835         struct btrfs_device *device;
1836         u64 super_flags;
1837 
1838         BUG_ON(!mutex_is_locked(&uuid_mutex));
1839         if (!fs_devices->seeding)
1840                 return -EINVAL;
1841 
1842         seed_devices = __alloc_fs_devices();
1843         if (IS_ERR(seed_devices))
1844                 return PTR_ERR(seed_devices);
1845 
1846         old_devices = clone_fs_devices(fs_devices);
1847         if (IS_ERR(old_devices)) {
1848                 kfree(seed_devices);
1849                 return PTR_ERR(old_devices);
1850         }
1851 
1852         list_add(&old_devices->list, &fs_uuids);
1853 
1854         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1855         seed_devices->opened = 1;
1856         INIT_LIST_HEAD(&seed_devices->devices);
1857         INIT_LIST_HEAD(&seed_devices->alloc_list);
1858         mutex_init(&seed_devices->device_list_mutex);
1859 
1860         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1861         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1862                               synchronize_rcu);
1863 
1864         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1865         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1866                 device->fs_devices = seed_devices;
1867         }
1868 
1869         fs_devices->seeding = 0;
1870         fs_devices->num_devices = 0;
1871         fs_devices->open_devices = 0;
1872         fs_devices->total_devices = 0;
1873         fs_devices->seed = seed_devices;
1874 
1875         generate_random_uuid(fs_devices->fsid);
1876         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1877         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1878         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1879 
1880         super_flags = btrfs_super_flags(disk_super) &
1881                       ~BTRFS_SUPER_FLAG_SEEDING;
1882         btrfs_set_super_flags(disk_super, super_flags);
1883 
1884         return 0;
1885 }
1886 
1887 /*
1888  * strore the expected generation for seed devices in device items.
1889  */
1890 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1891                                struct btrfs_root *root)
1892 {
1893         struct btrfs_path *path;
1894         struct extent_buffer *leaf;
1895         struct btrfs_dev_item *dev_item;
1896         struct btrfs_device *device;
1897         struct btrfs_key key;
1898         u8 fs_uuid[BTRFS_UUID_SIZE];
1899         u8 dev_uuid[BTRFS_UUID_SIZE];
1900         u64 devid;
1901         int ret;
1902 
1903         path = btrfs_alloc_path();
1904         if (!path)
1905                 return -ENOMEM;
1906 
1907         root = root->fs_info->chunk_root;
1908         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1909         key.offset = 0;
1910         key.type = BTRFS_DEV_ITEM_KEY;
1911 
1912         while (1) {
1913                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1914                 if (ret < 0)
1915                         goto error;
1916 
1917                 leaf = path->nodes[0];
1918 next_slot:
1919                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1920                         ret = btrfs_next_leaf(root, path);
1921                         if (ret > 0)
1922                                 break;
1923                         if (ret < 0)
1924                                 goto error;
1925                         leaf = path->nodes[0];
1926                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1927                         btrfs_release_path(path);
1928                         continue;
1929                 }
1930 
1931                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1932                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1933                     key.type != BTRFS_DEV_ITEM_KEY)
1934                         break;
1935 
1936                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1937                                           struct btrfs_dev_item);
1938                 devid = btrfs_device_id(leaf, dev_item);
1939                 read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
1940                                    BTRFS_UUID_SIZE);
1941                 read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
1942                                    BTRFS_UUID_SIZE);
1943                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1944                                            fs_uuid);
1945                 BUG_ON(!device); /* Logic error */
1946 
1947                 if (device->fs_devices->seeding) {
1948                         btrfs_set_device_generation(leaf, dev_item,
1949                                                     device->generation);
1950                         btrfs_mark_buffer_dirty(leaf);
1951                 }
1952 
1953                 path->slots[0]++;
1954                 goto next_slot;
1955         }
1956         ret = 0;
1957 error:
1958         btrfs_free_path(path);
1959         return ret;
1960 }
1961 
1962 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1963 {
1964         struct request_queue *q;
1965         struct btrfs_trans_handle *trans;
1966         struct btrfs_device *device;
1967         struct block_device *bdev;
1968         struct list_head *devices;
1969         struct super_block *sb = root->fs_info->sb;
1970         struct rcu_string *name;
1971         u64 total_bytes;
1972         int seeding_dev = 0;
1973         int ret = 0;
1974 
1975         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1976                 return -EROFS;
1977 
1978         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1979                                   root->fs_info->bdev_holder);
1980         if (IS_ERR(bdev))
1981                 return PTR_ERR(bdev);
1982 
1983         if (root->fs_info->fs_devices->seeding) {
1984                 seeding_dev = 1;
1985                 down_write(&sb->s_umount);
1986                 mutex_lock(&uuid_mutex);
1987         }
1988 
1989         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1990 
1991         devices = &root->fs_info->fs_devices->devices;
1992 
1993         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1994         list_for_each_entry(device, devices, dev_list) {
1995                 if (device->bdev == bdev) {
1996                         ret = -EEXIST;
1997                         mutex_unlock(
1998                                 &root->fs_info->fs_devices->device_list_mutex);
1999                         goto error;
2000                 }
2001         }
2002         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2003 
2004         device = btrfs_alloc_device(root->fs_info, NULL, NULL);
2005         if (IS_ERR(device)) {
2006                 /* we can safely leave the fs_devices entry around */
2007                 ret = PTR_ERR(device);
2008                 goto error;
2009         }
2010 
2011         name = rcu_string_strdup(device_path, GFP_NOFS);
2012         if (!name) {
2013                 kfree(device);
2014                 ret = -ENOMEM;
2015                 goto error;
2016         }
2017         rcu_assign_pointer(device->name, name);
2018 
2019         trans = btrfs_start_transaction(root, 0);
2020         if (IS_ERR(trans)) {
2021                 rcu_string_free(device->name);
2022                 kfree(device);
2023                 ret = PTR_ERR(trans);
2024                 goto error;
2025         }
2026 
2027         lock_chunks(root);
2028 
2029         q = bdev_get_queue(bdev);
2030         if (blk_queue_discard(q))
2031                 device->can_discard = 1;
2032         device->writeable = 1;
2033         device->generation = trans->transid;
2034         device->io_width = root->sectorsize;
2035         device->io_align = root->sectorsize;
2036         device->sector_size = root->sectorsize;
2037         device->total_bytes = i_size_read(bdev->bd_inode);
2038         device->disk_total_bytes = device->total_bytes;
2039         device->dev_root = root->fs_info->dev_root;
2040         device->bdev = bdev;
2041         device->in_fs_metadata = 1;
2042         device->is_tgtdev_for_dev_replace = 0;
2043         device->mode = FMODE_EXCL;
2044         device->dev_stats_valid = 1;
2045         set_blocksize(device->bdev, 4096);
2046 
2047         if (seeding_dev) {
2048                 sb->s_flags &= ~MS_RDONLY;
2049                 ret = btrfs_prepare_sprout(root);
2050                 BUG_ON(ret); /* -ENOMEM */
2051         }
2052 
2053         device->fs_devices = root->fs_info->fs_devices;
2054 
2055         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2056         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
2057         list_add(&device->dev_alloc_list,
2058                  &root->fs_info->fs_devices->alloc_list);
2059         root->fs_info->fs_devices->num_devices++;
2060         root->fs_info->fs_devices->open_devices++;
2061         root->fs_info->fs_devices->rw_devices++;
2062         root->fs_info->fs_devices->total_devices++;
2063         if (device->can_discard)
2064                 root->fs_info->fs_devices->num_can_discard++;
2065         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
2066 
2067         spin_lock(&root->fs_info->free_chunk_lock);
2068         root->fs_info->free_chunk_space += device->total_bytes;
2069         spin_unlock(&root->fs_info->free_chunk_lock);
2070 
2071         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
2072                 root->fs_info->fs_devices->rotating = 1;
2073 
2074         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
2075         btrfs_set_super_total_bytes(root->fs_info->super_copy,
2076                                     total_bytes + device->total_bytes);
2077 
2078         total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
2079         btrfs_set_super_num_devices(root->fs_info->super_copy,
2080                                     total_bytes + 1);
2081         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2082 
2083         if (seeding_dev) {
2084                 ret = init_first_rw_device(trans, root, device);
2085                 if (ret) {
2086                         btrfs_abort_transaction(trans, root, ret);
2087                         goto error_trans;
2088                 }
2089                 ret = btrfs_finish_sprout(trans, root);
2090                 if (ret) {
2091                         btrfs_abort_transaction(trans, root, ret);
2092                         goto error_trans;
2093                 }
2094         } else {
2095                 ret = btrfs_add_device(trans, root, device);
2096                 if (ret) {
2097                         btrfs_abort_transaction(trans, root, ret);
2098                         goto error_trans;
2099                 }
2100         }
2101 
2102         /*
2103          * we've got more storage, clear any full flags on the space
2104          * infos
2105          */
2106         btrfs_clear_space_info_full(root->fs_info);
2107 
2108         unlock_chunks(root);
2109         root->fs_info->num_tolerated_disk_barrier_failures =
2110                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
2111         ret = btrfs_commit_transaction(trans, root);
2112 
2113         if (seeding_dev) {
2114                 mutex_unlock(&uuid_mutex);
2115                 up_write(&sb->s_umount);
2116 
2117                 if (ret) /* transaction commit */
2118                         return ret;
2119 
2120                 ret = btrfs_relocate_sys_chunks(root);
2121                 if (ret < 0)
2122                         btrfs_error(root->fs_info, ret,
2123                                     "Failed to relocate sys chunks after "
2124                                     "device initialization. This can be fixed "
2125                                     "using the \"btrfs balance\" command.");
2126                 trans = btrfs_attach_transaction(root);
2127                 if (IS_ERR(trans)) {
2128                         if (PTR_ERR(trans) == -ENOENT)
2129                                 return 0;
2130                         return PTR_ERR(trans);
2131                 }
2132                 ret = btrfs_commit_transaction(trans, root);
2133         }
2134 
2135         return ret;
2136 
2137 error_trans:
2138         unlock_chunks(root);
2139         btrfs_end_transaction(trans, root);
2140         rcu_string_free(device->name);
2141         kfree(device);
2142 error:
2143         blkdev_put(bdev, FMODE_EXCL);
2144         if (seeding_dev) {
2145                 mutex_unlock(&uuid_mutex);
2146                 up_write(&sb->s_umount);
2147         }
2148         return ret;
2149 }
2150 
2151 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2152                                   struct btrfs_device **device_out)
2153 {
2154         struct request_queue *q;
2155         struct btrfs_device *device;
2156         struct block_device *bdev;
2157         struct btrfs_fs_info *fs_info = root->fs_info;
2158         struct list_head *devices;
2159         struct rcu_string *name;
2160         u64 devid = BTRFS_DEV_REPLACE_DEVID;
2161         int ret = 0;
2162 
2163         *device_out = NULL;
2164         if (fs_info->fs_devices->seeding)
2165                 return -EINVAL;
2166 
2167         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2168                                   fs_info->bdev_holder);
2169         if (IS_ERR(bdev))
2170                 return PTR_ERR(bdev);
2171 
2172         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2173 
2174         devices = &fs_info->fs_devices->devices;
2175         list_for_each_entry(device, devices, dev_list) {
2176                 if (device->bdev == bdev) {
2177                         ret = -EEXIST;
2178                         goto error;
2179                 }
2180         }
2181 
2182         device = btrfs_alloc_device(NULL, &devid, NULL);
2183         if (IS_ERR(device)) {
2184                 ret = PTR_ERR(device);
2185                 goto error;
2186         }
2187 
2188         name = rcu_string_strdup(device_path, GFP_NOFS);
2189         if (!name) {
2190                 kfree(device);
2191                 ret = -ENOMEM;
2192                 goto error;
2193         }
2194         rcu_assign_pointer(device->name, name);
2195 
2196         q = bdev_get_queue(bdev);
2197         if (blk_queue_discard(q))
2198                 device->can_discard = 1;
2199         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2200         device->writeable = 1;
2201         device->generation = 0;
2202         device->io_width = root->sectorsize;
2203         device->io_align = root->sectorsize;
2204         device->sector_size = root->sectorsize;
2205         device->total_bytes = i_size_read(bdev->bd_inode);
2206         device->disk_total_bytes = device->total_bytes;
2207         device->dev_root = fs_info->dev_root;
2208         device->bdev = bdev;
2209         device->in_fs_metadata = 1;
2210         device->is_tgtdev_for_dev_replace = 1;
2211         device->mode = FMODE_EXCL;
2212         device->dev_stats_valid = 1;
2213         set_blocksize(device->bdev, 4096);
2214         device->fs_devices = fs_info->fs_devices;
2215         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2216         fs_info->fs_devices->num_devices++;
2217         fs_info->fs_devices->open_devices++;
2218         if (device->can_discard)
2219                 fs_info->fs_devices->num_can_discard++;
2220         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2221 
2222         *device_out = device;
2223         return ret;
2224 
2225 error:
2226         blkdev_put(bdev, FMODE_EXCL);
2227         return ret;
2228 }
2229 
2230 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2231                                               struct btrfs_device *tgtdev)
2232 {
2233         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2234         tgtdev->io_width = fs_info->dev_root->sectorsize;
2235         tgtdev->io_align = fs_info->dev_root->sectorsize;
2236         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2237         tgtdev->dev_root = fs_info->dev_root;
2238         tgtdev->in_fs_metadata = 1;
2239 }
2240 
2241 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2242                                         struct btrfs_device *device)
2243 {
2244         int ret;
2245         struct btrfs_path *path;
2246         struct btrfs_root *root;
2247         struct btrfs_dev_item *dev_item;
2248         struct extent_buffer *leaf;
2249         struct btrfs_key key;
2250 
2251         root = device->dev_root->fs_info->chunk_root;
2252 
2253         path = btrfs_alloc_path();
2254         if (!path)
2255                 return -ENOMEM;
2256 
2257         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2258         key.type = BTRFS_DEV_ITEM_KEY;
2259         key.offset = device->devid;
2260 
2261         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2262         if (ret < 0)
2263                 goto out;
2264 
2265         if (ret > 0) {
2266                 ret = -ENOENT;
2267                 goto out;
2268         }
2269 
2270         leaf = path->nodes[0];
2271         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2272 
2273         btrfs_set_device_id(leaf, dev_item, device->devid);
2274         btrfs_set_device_type(leaf, dev_item, device->type);
2275         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2276         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2277         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2278         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
2279         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
2280         btrfs_mark_buffer_dirty(leaf);
2281 
2282 out:
2283         btrfs_free_path(path);
2284         return ret;
2285 }
2286 
2287 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
2288                       struct btrfs_device *device, u64 new_size)
2289 {
2290         struct btrfs_super_block *super_copy =
2291                 device->dev_root->fs_info->super_copy;
2292         u64 old_total = btrfs_super_total_bytes(super_copy);
2293         u64 diff = new_size - device->total_bytes;
2294 
2295         if (!device->writeable)
2296                 return -EACCES;
2297         if (new_size <= device->total_bytes ||
2298             device->is_tgtdev_for_dev_replace)
2299                 return -EINVAL;
2300 
2301         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2302         device->fs_devices->total_rw_bytes += diff;
2303 
2304         device->total_bytes = new_size;
2305         device->disk_total_bytes = new_size;
2306         btrfs_clear_space_info_full(device->dev_root->fs_info);
2307 
2308         return btrfs_update_device(trans, device);
2309 }
2310 
2311 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2312                       struct btrfs_device *device, u64 new_size)
2313 {
2314         int ret;
2315         lock_chunks(device->dev_root);
2316         ret = __btrfs_grow_device(trans, device, new_size);
2317         unlock_chunks(device->dev_root);
2318         return ret;
2319 }
2320 
2321 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2322                             struct btrfs_root *root,
2323                             u64 chunk_tree, u64 chunk_objectid,
2324                             u64 chunk_offset)
2325 {
2326         int ret;
2327         struct btrfs_path *path;
2328         struct btrfs_key key;
2329 
2330         root = root->fs_info->chunk_root;
2331         path = btrfs_alloc_path();
2332         if (!path)
2333                 return -ENOMEM;
2334 
2335         key.objectid = chunk_objectid;
2336         key.offset = chunk_offset;
2337         key.type = BTRFS_CHUNK_ITEM_KEY;
2338 
2339         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2340         if (ret < 0)
2341                 goto out;
2342         else if (ret > 0) { /* Logic error or corruption */
2343                 btrfs_error(root->fs_info, -ENOENT,
2344                             "Failed lookup while freeing chunk.");
2345                 ret = -ENOENT;
2346                 goto out;
2347         }
2348 
2349         ret = btrfs_del_item(trans, root, path);
2350         if (ret < 0)
2351                 btrfs_error(root->fs_info, ret,
2352                             "Failed to delete chunk item.");
2353 out:
2354         btrfs_free_path(path);
2355         return ret;
2356 }
2357 
2358 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2359                         chunk_offset)
2360 {
2361         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2362         struct btrfs_disk_key *disk_key;
2363         struct btrfs_chunk *chunk;
2364         u8 *ptr;
2365         int ret = 0;
2366         u32 num_stripes;
2367         u32 array_size;
2368         u32 len = 0;
2369         u32 cur;
2370         struct btrfs_key key;
2371 
2372         array_size = btrfs_super_sys_array_size(super_copy);
2373 
2374         ptr = super_copy->sys_chunk_array;
2375         cur = 0;
2376 
2377         while (cur < array_size) {
2378                 disk_key = (struct btrfs_disk_key *)ptr;
2379                 btrfs_disk_key_to_cpu(&key, disk_key);
2380 
2381                 len = sizeof(*disk_key);
2382 
2383                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2384                         chunk = (struct btrfs_chunk *)(ptr + len);
2385                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2386                         len += btrfs_chunk_item_size(num_stripes);
2387                 } else {
2388                         ret = -EIO;
2389                         break;
2390                 }
2391                 if (key.objectid == chunk_objectid &&
2392                     key.offset == chunk_offset) {
2393                         memmove(ptr, ptr + len, array_size - (cur + len));
2394                         array_size -= len;
2395                         btrfs_set_super_sys_array_size(super_copy, array_size);
2396                 } else {
2397                         ptr += len;
2398                         cur += len;
2399                 }
2400         }
2401         return ret;
2402 }
2403 
2404 static int btrfs_relocate_chunk(struct btrfs_root *root,
2405                          u64 chunk_tree, u64 chunk_objectid,
2406                          u64 chunk_offset)
2407 {
2408         struct extent_map_tree *em_tree;
2409         struct btrfs_root *extent_root;
2410         struct btrfs_trans_handle *trans;
2411         struct extent_map *em;
2412         struct map_lookup *map;
2413         int ret;
2414         int i;
2415 
2416         root = root->fs_info->chunk_root;
2417         extent_root = root->fs_info->extent_root;
2418         em_tree = &root->fs_info->mapping_tree.map_tree;
2419 
2420         ret = btrfs_can_relocate(extent_root, chunk_offset);
2421         if (ret)
2422                 return -ENOSPC;
2423 
2424         /* step one, relocate all the extents inside this chunk */
2425         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2426         if (ret)
2427                 return ret;
2428 
2429         trans = btrfs_start_transaction(root, 0);
2430         if (IS_ERR(trans)) {
2431                 ret = PTR_ERR(trans);
2432                 btrfs_std_error(root->fs_info, ret);
2433                 return ret;
2434         }
2435 
2436         lock_chunks(root);
2437 
2438         /*
2439          * step two, delete the device extents and the
2440          * chunk tree entries
2441          */
2442         read_lock(&em_tree->lock);
2443         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2444         read_unlock(&em_tree->lock);
2445 
2446         BUG_ON(!em || em->start > chunk_offset ||
2447                em->start + em->len < chunk_offset);
2448         map = (struct map_lookup *)em->bdev;
2449 
2450         for (i = 0; i < map->num_stripes; i++) {
2451                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
2452                                             map->stripes[i].physical);
2453                 BUG_ON(ret);
2454 
2455                 if (map->stripes[i].dev) {
2456                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2457                         BUG_ON(ret);
2458                 }
2459         }
2460         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
2461                                chunk_offset);
2462 
2463         BUG_ON(ret);
2464 
2465         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2466 
2467         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2468                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2469                 BUG_ON(ret);
2470         }
2471 
2472         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
2473         BUG_ON(ret);
2474 
2475         write_lock(&em_tree->lock);
2476         remove_extent_mapping(em_tree, em);
2477         write_unlock(&em_tree->lock);
2478 
2479         kfree(map);
2480         em->bdev = NULL;
2481 
2482         /* once for the tree */
2483         free_extent_map(em);
2484         /* once for us */
2485         free_extent_map(em);
2486 
2487         unlock_chunks(root);
2488         btrfs_end_transaction(trans, root);
2489         return 0;
2490 }
2491 
2492 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2493 {
2494         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2495         struct btrfs_path *path;
2496         struct extent_buffer *leaf;
2497         struct btrfs_chunk *chunk;
2498         struct btrfs_key key;
2499         struct btrfs_key found_key;
2500         u64 chunk_tree = chunk_root->root_key.objectid;
2501         u64 chunk_type;
2502         bool retried = false;
2503         int failed = 0;
2504         int ret;
2505 
2506         path = btrfs_alloc_path();
2507         if (!path)
2508                 return -ENOMEM;
2509 
2510 again:
2511         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2512         key.offset = (u64)-1;
2513         key.type = BTRFS_CHUNK_ITEM_KEY;
2514 
2515         while (1) {
2516                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2517                 if (ret < 0)
2518                         goto error;
2519                 BUG_ON(ret == 0); /* Corruption */
2520 
2521                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2522                                           key.type);
2523                 if (ret < 0)
2524                         goto error;
2525                 if (ret > 0)
2526                         break;
2527 
2528                 leaf = path->nodes[0];
2529                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2530 
2531                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2532                                        struct btrfs_chunk);
2533                 chunk_type = btrfs_chunk_type(leaf, chunk);
2534                 btrfs_release_path(path);
2535 
2536                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2537                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2538                                                    found_key.objectid,
2539                                                    found_key.offset);
2540                         if (ret == -ENOSPC)
2541                                 failed++;
2542                         else if (ret)
2543                                 BUG();
2544                 }
2545 
2546                 if (found_key.offset == 0)
2547                         break;
2548                 key.offset = found_key.offset - 1;
2549         }
2550         ret = 0;
2551         if (failed && !retried) {
2552                 failed = 0;
2553                 retried = true;
2554                 goto again;
2555         } else if (WARN_ON(failed && retried)) {
2556                 ret = -ENOSPC;
2557         }
2558 error:
2559         btrfs_free_path(path);
2560         return ret;
2561 }
2562 
2563 static int insert_balance_item(struct btrfs_root *root,
2564                                struct btrfs_balance_control *bctl)
2565 {
2566         struct btrfs_trans_handle *trans;
2567         struct btrfs_balance_item *item;
2568         struct btrfs_disk_balance_args disk_bargs;
2569         struct btrfs_path *path;
2570         struct extent_buffer *leaf;
2571         struct btrfs_key key;
2572         int ret, err;
2573 
2574         path = btrfs_alloc_path();
2575         if (!path)
2576                 return -ENOMEM;
2577 
2578         trans = btrfs_start_transaction(root, 0);
2579         if (IS_ERR(trans)) {
2580                 btrfs_free_path(path);
2581                 return PTR_ERR(trans);
2582         }
2583 
2584         key.objectid = BTRFS_BALANCE_OBJECTID;
2585         key.type = BTRFS_BALANCE_ITEM_KEY;
2586         key.offset = 0;
2587 
2588         ret = btrfs_insert_empty_item(trans, root, path, &key,
2589                                       sizeof(*item));
2590         if (ret)
2591                 goto out;
2592 
2593         leaf = path->nodes[0];
2594         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2595 
2596         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2597 
2598         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2599         btrfs_set_balance_data(leaf, item, &disk_bargs);
2600         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2601         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2602         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2603         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2604 
2605         btrfs_set_balance_flags(leaf, item, bctl->flags);
2606 
2607         btrfs_mark_buffer_dirty(leaf);
2608 out:
2609         btrfs_free_path(path);
2610         err = btrfs_commit_transaction(trans, root);
2611         if (err && !ret)
2612                 ret = err;
2613         return ret;
2614 }
2615 
2616 static int del_balance_item(struct btrfs_root *root)
2617 {
2618         struct btrfs_trans_handle *trans;
2619         struct btrfs_path *path;
2620         struct btrfs_key key;
2621         int ret, err;
2622 
2623         path = btrfs_alloc_path();
2624         if (!path)
2625                 return -ENOMEM;
2626 
2627         trans = btrfs_start_transaction(root, 0);
2628         if (IS_ERR(trans)) {
2629                 btrfs_free_path(path);
2630                 return PTR_ERR(trans);
2631         }
2632 
2633         key.objectid = BTRFS_BALANCE_OBJECTID;
2634         key.type = BTRFS_BALANCE_ITEM_KEY;
2635         key.offset = 0;
2636 
2637         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2638         if (ret < 0)
2639                 goto out;
2640         if (ret > 0) {
2641                 ret = -ENOENT;
2642                 goto out;
2643         }
2644 
2645         ret = btrfs_del_item(trans, root, path);
2646 out:
2647         btrfs_free_path(path);
2648         err = btrfs_commit_transaction(trans, root);
2649         if (err && !ret)
2650                 ret = err;
2651         return ret;
2652 }
2653 
2654 /*
2655  * This is a heuristic used to reduce the number of chunks balanced on
2656  * resume after balance was interrupted.
2657  */
2658 static void update_balance_args(struct btrfs_balance_control *bctl)
2659 {
2660         /*
2661          * Turn on soft mode for chunk types that were being converted.
2662          */
2663         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
2664                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
2665         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
2666                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
2667         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
2668                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
2669 
2670         /*
2671          * Turn on usage filter if is not already used.  The idea is
2672          * that chunks that we have already balanced should be
2673          * reasonably full.  Don't do it for chunks that are being
2674          * converted - that will keep us from relocating unconverted
2675          * (albeit full) chunks.
2676          */
2677         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2678             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2679                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
2680                 bctl->data.usage = 90;
2681         }
2682         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2683             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2684                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
2685                 bctl->sys.usage = 90;
2686         }
2687         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2688             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2689                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
2690                 bctl->meta.usage = 90;
2691         }
2692 }
2693 
2694 /*
2695  * Should be called with both balance and volume mutexes held to
2696  * serialize other volume operations (add_dev/rm_dev/resize) with
2697  * restriper.  Same goes for unset_balance_control.
2698  */
2699 static void set_balance_control(struct btrfs_balance_control *bctl)
2700 {
2701         struct btrfs_fs_info *fs_info = bctl->fs_info;
2702 
2703         BUG_ON(fs_info->balance_ctl);
2704 
2705         spin_lock(&fs_info->balance_lock);
2706         fs_info->balance_ctl = bctl;
2707         spin_unlock(&fs_info->balance_lock);
2708 }
2709 
2710 static void unset_balance_control(struct btrfs_fs_info *fs_info)
2711 {
2712         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2713 
2714         BUG_ON(!fs_info->balance_ctl);
2715 
2716         spin_lock(&fs_info->balance_lock);
2717         fs_info->balance_ctl = NULL;
2718         spin_unlock(&fs_info->balance_lock);
2719 
2720         kfree(bctl);
2721 }
2722 
2723 /*
2724  * Balance filters.  Return 1 if chunk should be filtered out
2725  * (should not be balanced).
2726  */
2727 static int chunk_profiles_filter(u64 chunk_type,
2728                                  struct btrfs_balance_args *bargs)
2729 {
2730         chunk_type = chunk_to_extended(chunk_type) &
2731                                 BTRFS_EXTENDED_PROFILE_MASK;
2732 
2733         if (bargs->profiles & chunk_type)
2734                 return 0;
2735 
2736         return 1;
2737 }
2738 
2739 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2740                               struct btrfs_balance_args *bargs)
2741 {
2742         struct btrfs_block_group_cache *cache;
2743         u64 chunk_used, user_thresh;
2744         int ret = 1;
2745 
2746         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2747         chunk_used = btrfs_block_group_used(&cache->item);
2748 
2749         if (bargs->usage == 0)
2750                 user_thresh = 1;
2751         else if (bargs->usage > 100)
2752                 user_thresh = cache->key.offset;
2753         else
2754                 user_thresh = div_factor_fine(cache->key.offset,
2755                                               bargs->usage);
2756 
2757         if (chunk_used < user_thresh)
2758                 ret = 0;
2759 
2760         btrfs_put_block_group(cache);
2761         return ret;
2762 }
2763 
2764 static int chunk_devid_filter(struct extent_buffer *leaf,
2765                               struct btrfs_chunk *chunk,
2766                               struct btrfs_balance_args *bargs)
2767 {
2768         struct btrfs_stripe *stripe;
2769         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2770         int i;
2771 
2772         for (i = 0; i < num_stripes; i++) {
2773                 stripe = btrfs_stripe_nr(chunk, i);
2774                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
2775                         return 0;
2776         }
2777 
2778         return 1;
2779 }
2780 
2781 /* [pstart, pend) */
2782 static int chunk_drange_filter(struct extent_buffer *leaf,
2783                                struct btrfs_chunk *chunk,
2784                                u64 chunk_offset,
2785                                struct btrfs_balance_args *bargs)
2786 {
2787         struct btrfs_stripe *stripe;
2788         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2789         u64 stripe_offset;
2790         u64 stripe_length;
2791         int factor;
2792         int i;
2793 
2794         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
2795                 return 0;
2796 
2797         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
2798              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) {
2799                 factor = num_stripes / 2;
2800         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) {
2801                 factor = num_stripes - 1;
2802         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) {
2803                 factor = num_stripes - 2;
2804         } else {
2805                 factor = num_stripes;
2806         }
2807 
2808         for (i = 0; i < num_stripes; i++) {
2809                 stripe = btrfs_stripe_nr(chunk, i);
2810                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
2811                         continue;
2812 
2813                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
2814                 stripe_length = btrfs_chunk_length(leaf, chunk);
2815                 do_div(stripe_length, factor);
2816 
2817                 if (stripe_offset < bargs->pend &&
2818                     stripe_offset + stripe_length > bargs->pstart)
2819                         return 0;
2820         }
2821 
2822         return 1;
2823 }
2824 
2825 /* [vstart, vend) */
2826 static int chunk_vrange_filter(struct extent_buffer *leaf,
2827                                struct btrfs_chunk *chunk,
2828                                u64 chunk_offset,
2829                                struct btrfs_balance_args *bargs)
2830 {
2831         if (chunk_offset < bargs->vend &&
2832             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
2833                 /* at least part of the chunk is inside this vrange */
2834                 return 0;
2835 
2836         return 1;
2837 }
2838 
2839 static int chunk_soft_convert_filter(u64 chunk_type,
2840                                      struct btrfs_balance_args *bargs)
2841 {
2842         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
2843                 return 0;
2844 
2845         chunk_type = chunk_to_extended(chunk_type) &
2846                                 BTRFS_EXTENDED_PROFILE_MASK;
2847 
2848         if (bargs->target == chunk_type)
2849                 return 1;
2850 
2851         return 0;
2852 }
2853 
2854 static int should_balance_chunk(struct btrfs_root *root,
2855                                 struct extent_buffer *leaf,
2856                                 struct btrfs_chunk *chunk, u64 chunk_offset)
2857 {
2858         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2859         struct btrfs_balance_args *bargs = NULL;
2860         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2861 
2862         /* type filter */
2863         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2864               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2865                 return 0;
2866         }
2867 
2868         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2869                 bargs = &bctl->data;
2870         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2871                 bargs = &bctl->sys;
2872         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2873                 bargs = &bctl->meta;
2874 
2875         /* profiles filter */
2876         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2877             chunk_profiles_filter(chunk_type, bargs)) {
2878                 return 0;
2879         }
2880 
2881         /* usage filter */
2882         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2883             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2884                 return 0;
2885         }
2886 
2887         /* devid filter */
2888         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
2889             chunk_devid_filter(leaf, chunk, bargs)) {
2890                 return 0;
2891         }
2892 
2893         /* drange filter, makes sense only with devid filter */
2894         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
2895             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
2896                 return 0;
2897         }
2898 
2899         /* vrange filter */
2900         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
2901             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
2902                 return 0;
2903         }
2904 
2905         /* soft profile changing mode */
2906         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
2907             chunk_soft_convert_filter(chunk_type, bargs)) {
2908                 return 0;
2909         }
2910 
2911         return 1;
2912 }
2913 
2914 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2915 {
2916         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2917         struct btrfs_root *chunk_root = fs_info->chunk_root;
2918         struct btrfs_root *dev_root = fs_info->dev_root;
2919         struct list_head *devices;
2920         struct btrfs_device *device;
2921         u64 old_size;
2922         u64 size_to_free;
2923         struct btrfs_chunk *chunk;
2924         struct btrfs_path *path;
2925         struct btrfs_key key;
2926         struct btrfs_key found_key;
2927         struct btrfs_trans_handle *trans;
2928         struct extent_buffer *leaf;
2929         int slot;
2930         int ret;
2931         int enospc_errors = 0;
2932         bool counting = true;
2933 
2934         /* step one make some room on all the devices */
2935         devices = &fs_info->fs_devices->devices;
2936         list_for_each_entry(device, devices, dev_list) {
2937                 old_size = device->total_bytes;
2938                 size_to_free = div_factor(old_size, 1);
2939                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2940                 if (!device->writeable ||
2941                     device->total_bytes - device->bytes_used > size_to_free ||
2942                     device->is_tgtdev_for_dev_replace)
2943                         continue;
2944 
2945                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2946                 if (ret == -ENOSPC)
2947                         break;
2948                 BUG_ON(ret);
2949 
2950                 trans = btrfs_start_transaction(dev_root, 0);
2951                 BUG_ON(IS_ERR(trans));
2952 
2953                 ret = btrfs_grow_device(trans, device, old_size);
2954                 BUG_ON(ret);
2955 
2956                 btrfs_end_transaction(trans, dev_root);
2957         }
2958 
2959         /* step two, relocate all the chunks */
2960         path = btrfs_alloc_path();
2961         if (!path) {
2962                 ret = -ENOMEM;
2963                 goto error;
2964         }
2965 
2966         /* zero out stat counters */
2967         spin_lock(&fs_info->balance_lock);
2968         memset(&bctl->stat, 0, sizeof(bctl->stat));
2969         spin_unlock(&fs_info->balance_lock);
2970 again:
2971         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2972         key.offset = (u64)-1;
2973         key.type = BTRFS_CHUNK_ITEM_KEY;
2974 
2975         while (1) {
2976                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
2977                     atomic_read(&fs_info->balance_cancel_req)) {
2978                         ret = -ECANCELED;
2979                         goto error;
2980                 }
2981 
2982                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2983                 if (ret < 0)
2984                         goto error;
2985 
2986                 /*
2987                  * this shouldn't happen, it means the last relocate
2988                  * failed
2989                  */
2990                 if (ret == 0)
2991                         BUG(); /* FIXME break ? */
2992 
2993                 ret = btrfs_previous_item(chunk_root, path, 0,
2994                                           BTRFS_CHUNK_ITEM_KEY);
2995                 if (ret) {
2996                         ret = 0;
2997                         break;
2998                 }
2999 
3000                 leaf = path->nodes[0];
3001                 slot = path->slots[0];
3002                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3003 
3004                 if (found_key.objectid != key.objectid)
3005                         break;
3006 
3007                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3008 
3009                 if (!counting) {
3010                         spin_lock(&fs_info->balance_lock);
3011                         bctl->stat.considered++;
3012                         spin_unlock(&fs_info->balance_lock);
3013                 }
3014 
3015                 ret = should_balance_chunk(chunk_root, leaf, chunk,
3016                                            found_key.offset);
3017                 btrfs_release_path(path);
3018                 if (!ret)
3019                         goto loop;
3020 
3021                 if (counting) {
3022                         spin_lock(&fs_info->balance_lock);
3023                         bctl->stat.expected++;
3024                         spin_unlock(&fs_info->balance_lock);
3025                         goto loop;
3026                 }
3027 
3028                 ret = btrfs_relocate_chunk(chunk_root,
3029                                            chunk_root->root_key.objectid,
3030                                            found_key.objectid,
3031                                            found_key.offset);
3032                 if (ret && ret != -ENOSPC)
3033                         goto error;
3034                 if (ret == -ENOSPC) {
3035                         enospc_errors++;
3036                 } else {
3037                         spin_lock(&fs_info->balance_lock);
3038                         bctl->stat.completed++;
3039                         spin_unlock(&fs_info->balance_lock);
3040                 }
3041 loop:
3042                 if (found_key.offset == 0)
3043                         break;
3044                 key.offset = found_key.offset - 1;
3045         }
3046 
3047         if (counting) {
3048                 btrfs_release_path(path);
3049                 counting = false;
3050                 goto again;
3051         }
3052 error:
3053         btrfs_free_path(path);
3054         if (enospc_errors) {
3055                 printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
3056                        enospc_errors);
3057                 if (!ret)
3058                         ret = -ENOSPC;
3059         }
3060 
3061         return ret;
3062 }
3063 
3064 /**
3065  * alloc_profile_is_valid - see if a given profile is valid and reduced
3066  * @flags: profile to validate
3067  * @extended: if true @flags is treated as an extended profile
3068  */
3069 static int alloc_profile_is_valid(u64 flags, int extended)
3070 {
3071         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
3072                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
3073 
3074         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
3075 
3076         /* 1) check that all other bits are zeroed */
3077         if (flags & ~mask)
3078                 return 0;
3079 
3080         /* 2) see if profile is reduced */
3081         if (flags == 0)
3082                 return !extended; /* "" is valid for usual profiles */
3083 
3084         /* true if exactly one bit set */
3085         return (flags & (flags - 1)) == 0;
3086 }
3087 
3088 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
3089 {
3090         /* cancel requested || normal exit path */
3091         return atomic_read(&fs_info->balance_cancel_req) ||
3092                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
3093                  atomic_read(&fs_info->balance_cancel_req) == 0);
3094 }
3095 
3096 static void __cancel_balance(struct btrfs_fs_info *fs_info)
3097 {
3098         int ret;
3099 
3100         unset_balance_control(fs_info);
3101         ret = del_balance_item(fs_info->tree_root);
3102         if (ret)
3103                 btrfs_std_error(fs_info, ret);
3104 
3105         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3106 }
3107 
3108 /*
3109  * Should be called with both balance and volume mutexes held
3110  */
3111 int btrfs_balance(struct btrfs_balance_control *bctl,
3112                   struct btrfs_ioctl_balance_args *bargs)
3113 {
3114         struct btrfs_fs_info *fs_info = bctl->fs_info;
3115         u64 allowed;
3116         int mixed = 0;
3117         int ret;
3118         u64 num_devices;
3119         unsigned seq;
3120 
3121         if (btrfs_fs_closing(fs_info) ||
3122             atomic_read(&fs_info->balance_pause_req) ||
3123             atomic_read(&fs_info->balance_cancel_req)) {
3124                 ret = -EINVAL;
3125                 goto out;
3126         }
3127 
3128         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
3129         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
3130                 mixed = 1;
3131 
3132         /*
3133          * In case of mixed groups both data and meta should be picked,
3134          * and identical options should be given for both of them.
3135          */
3136         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
3137         if (mixed && (bctl->flags & allowed)) {
3138                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
3139                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
3140                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
3141                         printk(KERN_ERR "btrfs: with mixed groups data and "
3142                                "metadata balance options must be the same\n");
3143                         ret = -EINVAL;
3144                         goto out;
3145                 }
3146         }
3147 
3148         num_devices = fs_info->fs_devices->num_devices;
3149         btrfs_dev_replace_lock(&fs_info->dev_replace);
3150         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3151                 BUG_ON(num_devices < 1);
3152                 num_devices--;
3153         }
3154         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3155         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3156         if (num_devices == 1)
3157                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3158         else if (num_devices > 1)
3159                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3160         if (num_devices > 2)
3161                 allowed |= BTRFS_BLOCK_GROUP_RAID5;
3162         if (num_devices > 3)
3163                 allowed |= (BTRFS_BLOCK_GROUP_RAID10 |
3164                             BTRFS_BLOCK_GROUP_RAID6);
3165         if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3166             (!alloc_profile_is_valid(bctl->data.target, 1) ||
3167              (bctl->data.target & ~allowed))) {
3168                 printk(KERN_ERR "btrfs: unable to start balance with target "
3169                        "data profile %llu\n",
3170                        bctl->data.target);
3171                 ret = -EINVAL;
3172                 goto out;
3173         }
3174         if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3175             (!alloc_profile_is_valid(bctl->meta.target, 1) ||
3176              (bctl->meta.target & ~allowed))) {
3177                 printk(KERN_ERR "btrfs: unable to start balance with target "
3178                        "metadata profile %llu\n",
3179                        bctl->meta.target);
3180                 ret = -EINVAL;
3181                 goto out;
3182         }
3183         if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3184             (!alloc_profile_is_valid(bctl->sys.target, 1) ||
3185              (bctl->sys.target & ~allowed))) {
3186                 printk(KERN_ERR "btrfs: unable to start balance with target "
3187                        "system profile %llu\n",
3188                        bctl->sys.target);
3189                 ret = -EINVAL;
3190                 goto out;
3191         }
3192 
3193         /* allow dup'ed data chunks only in mixed mode */
3194         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3195             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
3196                 printk(KERN_ERR "btrfs: dup for data is not allowed\n");
3197                 ret = -EINVAL;
3198                 goto out;
3199         }
3200 
3201         /* allow to reduce meta or sys integrity only if force set */
3202         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3203                         BTRFS_BLOCK_GROUP_RAID10 |
3204                         BTRFS_BLOCK_GROUP_RAID5 |
3205                         BTRFS_BLOCK_GROUP_RAID6;
3206         do {
3207                 seq = read_seqbegin(&fs_info->profiles_lock);
3208 
3209                 if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3210                      (fs_info->avail_system_alloc_bits & allowed) &&
3211                      !(bctl->sys.target & allowed)) ||
3212                     ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3213                      (fs_info->avail_metadata_alloc_bits & allowed) &&
3214                      !(bctl->meta.target & allowed))) {
3215                         if (bctl->flags & BTRFS_BALANCE_FORCE) {
3216                                 printk(KERN_INFO "btrfs: force reducing metadata "
3217                                        "integrity\n");
3218                         } else {
3219                                 printk(KERN_ERR "btrfs: balance will reduce metadata "
3220                                        "integrity, use force if you want this\n");
3221                                 ret = -EINVAL;
3222                                 goto out;
3223                         }
3224                 }
3225         } while (read_seqretry(&fs_info->profiles_lock, seq));
3226 
3227         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3228                 int num_tolerated_disk_barrier_failures;
3229                 u64 target = bctl->sys.target;
3230 
3231                 num_tolerated_disk_barrier_failures =
3232                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3233                 if (num_tolerated_disk_barrier_failures > 0 &&
3234                     (target &
3235                      (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3236                       BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
3237                         num_tolerated_disk_barrier_failures = 0;
3238                 else if (num_tolerated_disk_barrier_failures > 1 &&
3239                          (target &
3240                           (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
3241                         num_tolerated_disk_barrier_failures = 1;
3242 
3243                 fs_info->num_tolerated_disk_barrier_failures =
3244                         num_tolerated_disk_barrier_failures;
3245         }
3246 
3247         ret = insert_balance_item(fs_info->tree_root, bctl);
3248         if (ret && ret != -EEXIST)
3249                 goto out;
3250 
3251         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3252                 BUG_ON(ret == -EEXIST);
3253                 set_balance_control(bctl);
3254         } else {
3255                 BUG_ON(ret != -EEXIST);
3256                 spin_lock(&fs_info->balance_lock);
3257                 update_balance_args(bctl);
3258                 spin_unlock(&fs_info->balance_lock);
3259         }
3260 
3261         atomic_inc(&fs_info->balance_running);
3262         mutex_unlock(&fs_info->balance_mutex);
3263 
3264         ret = __btrfs_balance(fs_info);
3265 
3266         mutex_lock(&fs_info->balance_mutex);
3267         atomic_dec(&fs_info->balance_running);
3268 
3269         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3270                 fs_info->num_tolerated_disk_barrier_failures =
3271                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3272         }
3273 
3274         if (bargs) {
3275                 memset(bargs, 0, sizeof(*bargs));
3276                 update_ioctl_balance_args(fs_info, 0, bargs);
3277         }
3278 
3279         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3280             balance_need_close(fs_info)) {
3281                 __cancel_balance(fs_info);
3282         }
3283 
3284         wake_up(&fs_info->balance_wait_q);
3285 
3286         return ret;
3287 out:
3288         if (bctl->flags & BTRFS_BALANCE_RESUME)
3289                 __cancel_balance(fs_info);
3290         else {
3291                 kfree(bctl);
3292                 atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3293         }
3294         return ret;
3295 }
3296 
3297 static int balance_kthread(void *data)
3298 {
3299         struct btrfs_fs_info *fs_info = data;
3300         int ret = 0;
3301 
3302         mutex_lock(&fs_info->volume_mutex);
3303         mutex_lock(&fs_info->balance_mutex);
3304 
3305         if (fs_info->balance_ctl) {
3306                 printk(KERN_INFO "btrfs: continuing balance\n");
3307                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3308         }
3309 
3310         mutex_unlock(&fs_info->balance_mutex);
3311         mutex_unlock(&fs_info->volume_mutex);
3312 
3313         return ret;
3314 }
3315 
3316 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3317 {
3318         struct task_struct *tsk;
3319 
3320         spin_lock(&fs_info->balance_lock);
3321         if (!fs_info->balance_ctl) {
3322                 spin_unlock(&fs_info->balance_lock);
3323                 return 0;
3324         }
3325         spin_unlock(&fs_info->balance_lock);
3326 
3327         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3328                 printk(KERN_INFO "btrfs: force skipping balance\n");
3329                 return 0;
3330         }
3331 
3332         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3333         return PTR_ERR_OR_ZERO(tsk);
3334 }
3335 
3336 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3337 {
3338         struct btrfs_balance_control *bctl;
3339         struct btrfs_balance_item *item;
3340         struct btrfs_disk_balance_args disk_bargs;
3341         struct btrfs_path *path;
3342         struct extent_buffer *leaf;
3343         struct btrfs_key key;
3344         int ret;
3345 
3346         path = btrfs_alloc_path();
3347         if (!path)
3348                 return -ENOMEM;
3349 
3350         key.objectid = BTRFS_BALANCE_OBJECTID;
3351         key.type = BTRFS_BALANCE_ITEM_KEY;
3352         key.offset = 0;
3353 
3354         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3355         if (ret < 0)
3356                 goto out;
3357         if (ret > 0) { /* ret = -ENOENT; */
3358                 ret = 0;
3359                 goto out;
3360         }
3361 
3362         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3363         if (!bctl) {
3364                 ret = -ENOMEM;
3365                 goto out;
3366         }
3367 
3368         leaf = path->nodes[0];
3369         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3370 
3371         bctl->fs_info = fs_info;
3372         bctl->flags = btrfs_balance_flags(leaf, item);
3373         bctl->flags |= BTRFS_BALANCE_RESUME;
3374 
3375         btrfs_balance_data(leaf, item, &disk_bargs);
3376         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3377         btrfs_balance_meta(leaf, item, &disk_bargs);
3378         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3379         btrfs_balance_sys(leaf, item, &disk_bargs);
3380         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3381 
3382         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3383 
3384         mutex_lock(&fs_info->volume_mutex);
3385         mutex_lock(&fs_info->balance_mutex);
3386 
3387         set_balance_control(bctl);
3388 
3389         mutex_unlock(&fs_info->balance_mutex);
3390         mutex_unlock(&fs_info->volume_mutex);
3391 out:
3392         btrfs_free_path(path);
3393         return ret;
3394 }
3395 
3396 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3397 {
3398         int ret = 0;
3399 
3400         mutex_lock(&fs_info->balance_mutex);
3401         if (!fs_info->balance_ctl) {
3402                 mutex_unlock(&fs_info->balance_mutex);
3403                 return -ENOTCONN;
3404         }
3405 
3406         if (atomic_read(&fs_info->balance_running)) {
3407                 atomic_inc(&fs_info->balance_pause_req);
3408                 mutex_unlock(&fs_info->balance_mutex);
3409 
3410                 wait_event(fs_info->balance_wait_q,
3411                            atomic_read(&fs_info->balance_running) == 0);
3412 
3413                 mutex_lock(&fs_info->balance_mutex);
3414                 /* we are good with balance_ctl ripped off from under us */
3415                 BUG_ON(atomic_read(&fs_info->balance_running));
3416                 atomic_dec(&fs_info->balance_pause_req);
3417         } else {
3418                 ret = -ENOTCONN;
3419         }
3420 
3421         mutex_unlock(&fs_info->balance_mutex);
3422         return ret;
3423 }
3424 
3425 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3426 {
3427         if (fs_info->sb->s_flags & MS_RDONLY)
3428                 return -EROFS;
3429 
3430         mutex_lock(&fs_info->balance_mutex);
3431         if (!fs_info->balance_ctl) {
3432                 mutex_unlock(&fs_info->balance_mutex);
3433                 return -ENOTCONN;
3434         }
3435 
3436         atomic_inc(&fs_info->balance_cancel_req);
3437         /*
3438          * if we are running just wait and return, balance item is
3439          * deleted in btrfs_balance in this case
3440          */
3441         if (atomic_read(&fs_info->balance_running)) {
3442                 mutex_unlock(&fs_info->balance_mutex);
3443                 wait_event(fs_info->balance_wait_q,
3444                            atomic_read(&fs_info->balance_running) == 0);
3445                 mutex_lock(&fs_info->balance_mutex);
3446         } else {
3447                 /* __cancel_balance needs volume_mutex */
3448                 mutex_unlock(&fs_info->balance_mutex);
3449                 mutex_lock(&fs_info->volume_mutex);
3450                 mutex_lock(&fs_info->balance_mutex);
3451 
3452                 if (fs_info->balance_ctl)
3453                         __cancel_balance(fs_info);
3454 
3455                 mutex_unlock(&fs_info->volume_mutex);
3456         }
3457 
3458         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3459         atomic_dec(&fs_info->balance_cancel_req);
3460         mutex_unlock(&fs_info->balance_mutex);
3461         return 0;
3462 }
3463 
3464 static int btrfs_uuid_scan_kthread(void *data)
3465 {
3466         struct btrfs_fs_info *fs_info = data;
3467         struct btrfs_root *root = fs_info->tree_root;
3468         struct btrfs_key key;
3469         struct btrfs_key max_key;
3470         struct btrfs_path *path = NULL;
3471         int ret = 0;
3472         struct extent_buffer *eb;
3473         int slot;
3474         struct btrfs_root_item root_item;
3475         u32 item_size;
3476         struct btrfs_trans_handle *trans = NULL;
3477 
3478         path = btrfs_alloc_path();
3479         if (!path) {
3480                 ret = -ENOMEM;
3481                 goto out;
3482         }
3483 
3484         key.objectid = 0;
3485         key.type = BTRFS_ROOT_ITEM_KEY;
3486         key.offset = 0;
3487 
3488         max_key.objectid = (u64)-1;
3489         max_key.type = BTRFS_ROOT_ITEM_KEY;
3490         max_key.offset = (u64)-1;
3491 
3492         path->keep_locks = 1;
3493 
3494         while (1) {
3495                 ret = btrfs_search_forward(root, &key, path, 0);
3496                 if (ret) {
3497                         if (ret > 0)
3498                                 ret = 0;
3499                         break;
3500                 }
3501 
3502                 if (key.type != BTRFS_ROOT_ITEM_KEY ||
3503                     (key.objectid < BTRFS_FIRST_FREE_OBJECTID &&
3504                      key.objectid != BTRFS_FS_TREE_OBJECTID) ||
3505                     key.objectid > BTRFS_LAST_FREE_OBJECTID)
3506                         goto skip;
3507 
3508                 eb = path->nodes[0];
3509                 slot = path->slots[0];
3510                 item_size = btrfs_item_size_nr(eb, slot);
3511                 if (item_size < sizeof(root_item))
3512                         goto skip;
3513 
3514                 read_extent_buffer(eb, &root_item,
3515                                    btrfs_item_ptr_offset(eb, slot),
3516                                    (int)sizeof(root_item));
3517                 if (btrfs_root_refs(&root_item) == 0)
3518                         goto skip;
3519 
3520                 if (!btrfs_is_empty_uuid(root_item.uuid) ||
3521                     !btrfs_is_empty_uuid(root_item.received_uuid)) {
3522                         if (trans)
3523                                 goto update_tree;
3524 
3525                         btrfs_release_path(path);
3526                         /*
3527                          * 1 - subvol uuid item
3528                          * 1 - received_subvol uuid item
3529                          */
3530                         trans = btrfs_start_transaction(fs_info->uuid_root, 2);
3531                         if (IS_ERR(trans)) {
3532                                 ret = PTR_ERR(trans);
3533                                 break;
3534                         }
3535                         continue;
3536                 } else {
3537                         goto skip;
3538                 }
3539 update_tree:
3540                 if (!btrfs_is_empty_uuid(root_item.uuid)) {
3541                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
3542                                                   root_item.uuid,
3543                                                   BTRFS_UUID_KEY_SUBVOL,
3544                                                   key.objectid);
3545                         if (ret < 0) {
3546                                 pr_warn("btrfs: uuid_tree_add failed %d\n",
3547                                         ret);
3548                                 break;
3549                         }
3550                 }
3551 
3552                 if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
3553                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
3554                                                   root_item.received_uuid,
3555                                                  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
3556                                                   key.objectid);
3557                         if (ret < 0) {
3558                                 pr_warn("btrfs: uuid_tree_add failed %d\n",
3559                                         ret);
3560                                 break;
3561                         }
3562                 }
3563 
3564 skip:
3565                 if (trans) {
3566                         ret = btrfs_end_transaction(trans, fs_info->uuid_root);
3567                         trans = NULL;
3568                         if (ret)
3569                                 break;
3570                 }
3571 
3572                 btrfs_release_path(path);
3573                 if (key.offset < (u64)-1) {
3574                         key.offset++;
3575                 } else if (key.type < BTRFS_ROOT_ITEM_KEY) {
3576                         key.offset = 0;
3577                         key.type = BTRFS_ROOT_ITEM_KEY;
3578                 } else if (key.objectid < (u64)-1) {
3579                         key.offset = 0;
3580                         key.type = BTRFS_ROOT_ITEM_KEY;
3581                         key.objectid++;
3582                 } else {
3583                         break;
3584                 }
3585                 cond_resched();
3586         }
3587 
3588 out:
3589         btrfs_free_path(path);
3590         if (trans && !IS_ERR(trans))
3591                 btrfs_end_transaction(trans, fs_info->uuid_root);
3592         if (ret)
3593                 pr_warn("btrfs: btrfs_uuid_scan_kthread failed %d\n", ret);
3594         else
3595                 fs_info->update_uuid_tree_gen = 1;
3596         up(&fs_info->uuid_tree_rescan_sem);
3597         return 0;
3598 }
3599 
3600 /*
3601  * Callback for btrfs_uuid_tree_iterate().
3602  * returns:
3603  * 0    check succeeded, the entry is not outdated.
3604  * < 0  if an error occured.
3605  * > 0  if the check failed, which means the caller shall remove the entry.
3606  */
3607 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
3608                                        u8 *uuid, u8 type, u64 subid)
3609 {
3610         struct btrfs_key key;
3611         int ret = 0;
3612         struct btrfs_root *subvol_root;
3613 
3614         if (type != BTRFS_UUID_KEY_SUBVOL &&
3615             type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
3616                 goto out;
3617 
3618         key.objectid = subid;
3619         key.type = BTRFS_ROOT_ITEM_KEY;
3620         key.offset = (u64)-1;
3621         subvol_root = btrfs_read_fs_root_no_name(fs_info, &key);
3622         if (IS_ERR(subvol_root)) {
3623                 ret = PTR_ERR(subvol_root);
3624                 if (ret == -ENOENT)
3625                         ret = 1;
3626                 goto out;
3627         }
3628 
3629         switch (type) {
3630         case BTRFS_UUID_KEY_SUBVOL:
3631                 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
3632                         ret = 1;
3633                 break;
3634         case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
3635                 if (memcmp(uuid, subvol_root->root_item.received_uuid,
3636                            BTRFS_UUID_SIZE))
3637                         ret = 1;
3638                 break;
3639         }
3640 
3641 out:
3642         return ret;
3643 }
3644 
3645 static int btrfs_uuid_rescan_kthread(void *data)
3646 {
3647         struct btrfs_fs_info *fs_info = (struct btrfs_fs_info *)data;
3648         int ret;
3649 
3650         /*
3651          * 1st step is to iterate through the existing UUID tree and
3652          * to delete all entries that contain outdated data.
3653          * 2nd step is to add all missing entries to the UUID tree.
3654          */
3655         ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
3656         if (ret < 0) {
3657                 pr_warn("btrfs: iterating uuid_tree failed %d\n", ret);
3658                 up(&fs_info->uuid_tree_rescan_sem);
3659                 return ret;
3660         }
3661         return btrfs_uuid_scan_kthread(data);
3662 }
3663 
3664 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
3665 {
3666         struct btrfs_trans_handle *trans;
3667         struct btrfs_root *tree_root = fs_info->tree_root;
3668         struct btrfs_root *uuid_root;
3669         struct task_struct *task;
3670         int ret;
3671 
3672         /*
3673          * 1 - root node
3674          * 1 - root item
3675          */
3676         trans = btrfs_start_transaction(tree_root, 2);
3677         if (IS_ERR(trans))
3678                 return PTR_ERR(trans);
3679 
3680         uuid_root = btrfs_create_tree(trans, fs_info,
3681                                       BTRFS_UUID_TREE_OBJECTID);
3682         if (IS_ERR(uuid_root)) {
3683                 btrfs_abort_transaction(trans, tree_root,
3684                                         PTR_ERR(uuid_root));
3685                 return PTR_ERR(uuid_root);
3686         }
3687 
3688         fs_info->uuid_root = uuid_root;
3689 
3690         ret = btrfs_commit_transaction(trans, tree_root);
3691         if (ret)
3692                 return ret;
3693 
3694         down(&fs_info->uuid_tree_rescan_sem);
3695         task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
3696         if (IS_ERR(task)) {
3697                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
3698                 pr_warn("btrfs: failed to start uuid_scan task\n");
3699                 up(&fs_info->uuid_tree_rescan_sem);
3700                 return PTR_ERR(task);
3701         }
3702 
3703         return 0;
3704 }
3705 
3706 int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
3707 {
3708         struct task_struct *task;
3709 
3710         down(&fs_info->uuid_tree_rescan_sem);
3711         task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
3712         if (IS_ERR(task)) {
3713                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
3714                 pr_warn("btrfs: failed to start uuid_rescan task\n");
3715                 up(&fs_info->uuid_tree_rescan_sem);
3716                 return PTR_ERR(task);
3717         }
3718 
3719         return 0;
3720 }
3721 
3722 /*
3723  * shrinking a device means finding all of the device extents past
3724  * the new size, and then following the back refs to the chunks.
3725  * The chunk relocation code actually frees the device extent
3726  */
3727 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
3728 {
3729         struct btrfs_trans_handle *trans;
3730         struct btrfs_root *root = device->dev_root;
3731         struct btrfs_dev_extent *dev_extent = NULL;
3732         struct btrfs_path *path;
3733         u64 length;
3734         u64 chunk_tree;
3735         u64 chunk_objectid;
3736         u64 chunk_offset;
3737         int ret;
3738         int slot;
3739         int failed = 0;
3740         bool retried = false;
3741         struct extent_buffer *l;
3742         struct btrfs_key key;
3743         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3744         u64 old_total = btrfs_super_total_bytes(super_copy);
3745         u64 old_size = device->total_bytes;
3746         u64 diff = device->total_bytes - new_size;
3747 
3748         if (device->is_tgtdev_for_dev_replace)
3749                 return -EINVAL;
3750 
3751         path = btrfs_alloc_path();
3752         if (!path)
3753                 return -ENOMEM;
3754 
3755         path->reada = 2;
3756 
3757         lock_chunks(root);
3758 
3759         device->total_bytes = new_size;
3760         if (device->writeable) {
3761                 device->fs_devices->total_rw_bytes -= diff;
3762                 spin_lock(&root->fs_info->free_chunk_lock);
3763                 root->fs_info->free_chunk_space -= diff;
3764                 spin_unlock(&root->fs_info->free_chunk_lock);
3765         }
3766         unlock_chunks(root);
3767 
3768 again:
3769         key.objectid = device->devid;
3770         key.offset = (u64)-1;
3771         key.type = BTRFS_DEV_EXTENT_KEY;
3772 
3773         do {
3774                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3775                 if (ret < 0)
3776                         goto done;
3777 
3778                 ret = btrfs_previous_item(root, path, 0, key.type);
3779                 if (ret < 0)
3780                         goto done;
3781                 if (ret) {
3782                         ret = 0;
3783                         btrfs_release_path(path);
3784                         break;
3785                 }
3786 
3787                 l = path->nodes[0];
3788                 slot = path->slots[0];
3789                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
3790 
3791                 if (key.objectid != device->devid) {
3792                         btrfs_release_path(path);
3793                         break;
3794                 }
3795 
3796                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3797                 length = btrfs_dev_extent_length(l, dev_extent);
3798 
3799                 if (key.offset + length <= new_size) {
3800                         btrfs_release_path(path);
3801                         break;
3802                 }
3803 
3804                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
3805                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
3806                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3807                 btrfs_release_path(path);
3808 
3809                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
3810                                            chunk_offset);
3811                 if (ret && ret != -ENOSPC)
3812                         goto done;
3813                 if (ret == -ENOSPC)
3814                         failed++;
3815         } while (key.offset-- > 0);
3816 
3817         if (failed && !retried) {
3818                 failed = 0;
3819                 retried = true;
3820                 goto again;
3821         } else if (failed && retried) {
3822                 ret = -ENOSPC;
3823                 lock_chunks(root);
3824 
3825                 device->total_bytes = old_size;
3826                 if (device->writeable)
3827                         device->fs_devices->total_rw_bytes += diff;
3828                 spin_lock(&root->fs_info->free_chunk_lock);
3829                 root->fs_info->free_chunk_space += diff;
3830                 spin_unlock(&root->fs_info->free_chunk_lock);
3831                 unlock_chunks(root);
3832                 goto done;
3833         }
3834 
3835         /* Shrinking succeeded, else we would be at "done". */
3836         trans = btrfs_start_transaction(root, 0);
3837         if (IS_ERR(trans)) {
3838                 ret = PTR_ERR(trans);
3839                 goto done;
3840         }
3841 
3842         lock_chunks(root);
3843 
3844         device->disk_total_bytes = new_size;
3845         /* Now btrfs_update_device() will change the on-disk size. */
3846         ret = btrfs_update_device(trans, device);
3847         if (ret) {
3848                 unlock_chunks(root);
3849                 btrfs_end_transaction(trans, root);
3850                 goto done;
3851         }
3852         WARN_ON(diff > old_total);
3853         btrfs_set_super_total_bytes(super_copy, old_total - diff);
3854         unlock_chunks(root);
3855         btrfs_end_transaction(trans, root);
3856 done:
3857         btrfs_free_path(path);
3858         return ret;
3859 }
3860 
3861 static int btrfs_add_system_chunk(struct btrfs_root *root,
3862                            struct btrfs_key *key,
3863                            struct btrfs_chunk *chunk, int item_size)
3864 {
3865         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3866         struct btrfs_disk_key disk_key;
3867         u32 array_size;
3868         u8 *ptr;
3869 
3870         array_size = btrfs_super_sys_array_size(super_copy);
3871         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
3872                 return -EFBIG;
3873 
3874         ptr = super_copy->sys_chunk_array + array_size;
3875         btrfs_cpu_key_to_disk(&disk_key, key);
3876         memcpy(ptr, &disk_key, sizeof(disk_key));
3877         ptr += sizeof(disk_key);
3878         memcpy(ptr, chunk, item_size);
3879         item_size += sizeof(disk_key);
3880         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
3881         return 0;
3882 }
3883 
3884 /*
3885  * sort the devices in descending order by max_avail, total_avail
3886  */
3887 static int btrfs_cmp_device_info(const void *a, const void *b)
3888 {
3889         const struct btrfs_device_info *di_a = a;
3890         const struct btrfs_device_info *di_b = b;
3891 
3892         if (di_a->max_avail > di_b->max_avail)
3893                 return -1;
3894         if (di_a->max_avail < di_b->max_avail)
3895                 return 1;
3896         if (di_a->total_avail > di_b->total_avail)
3897                 return -1;
3898         if (di_a->total_avail < di_b->total_avail)
3899                 return 1;
3900         return 0;
3901 }
3902 
3903 static struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
3904         [BTRFS_RAID_RAID10] = {
3905                 .sub_stripes    = 2,
3906                 .dev_stripes    = 1,
3907                 .devs_max       = 0,    /* 0 == as many as possible */
3908                 .devs_min       = 4,
3909                 .devs_increment = 2,
3910                 .ncopies        = 2,
3911         },
3912         [BTRFS_RAID_RAID1] = {
3913                 .sub_stripes    = 1,
3914                 .dev_stripes    = 1,
3915                 .devs_max       = 2,
3916                 .devs_min       = 2,
3917                 .devs_increment = 2,
3918                 .ncopies        = 2,
3919         },
3920         [BTRFS_RAID_DUP] = {
3921                 .sub_stripes    = 1,
3922                 .dev_stripes    = 2,
3923                 .devs_max       = 1,
3924                 .devs_min       = 1,
3925                 .devs_increment = 1,
3926                 .ncopies        = 2,
3927         },
3928         [BTRFS_RAID_RAID0] = {
3929                 .sub_stripes    = 1,
3930                 .dev_stripes    = 1,
3931                 .devs_max       = 0,
3932                 .devs_min       = 2,
3933                 .devs_increment = 1,
3934                 .ncopies        = 1,
3935         },
3936         [BTRFS_RAID_SINGLE] = {
3937                 .sub_stripes    = 1,
3938                 .dev_stripes    = 1,
3939                 .devs_max       = 1,
3940                 .devs_min       = 1,
3941                 .devs_increment = 1,
3942                 .ncopies        = 1,
3943         },
3944         [BTRFS_RAID_RAID5] = {
3945                 .sub_stripes    = 1,
3946                 .dev_stripes    = 1,
3947                 .devs_max       = 0,
3948                 .devs_min       = 2,
3949                 .devs_increment = 1,
3950                 .ncopies        = 2,
3951         },
3952         [BTRFS_RAID_RAID6] = {
3953                 .sub_stripes    = 1,
3954                 .dev_stripes    = 1,
3955                 .devs_max       = 0,
3956                 .devs_min       = 3,
3957                 .devs_increment = 1,
3958                 .ncopies        = 3,
3959         },
3960 };
3961 
3962 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
3963 {
3964         /* TODO allow them to set a preferred stripe size */
3965         return 64 * 1024;
3966 }
3967 
3968 static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
3969 {
3970         if (!(type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)))
3971                 return;
3972 
3973         btrfs_set_fs_incompat(info, RAID56);
3974 }
3975 
3976 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3977                                struct btrfs_root *extent_root, u64 start,
3978                                u64 type)
3979 {
3980         struct btrfs_fs_info *info = extent_root->fs_info;
3981         struct btrfs_fs_devices *fs_devices = info->fs_devices;
3982         struct list_head *cur;
3983         struct map_lookup *map = NULL;
3984         struct extent_map_tree *em_tree;
3985         struct extent_map *em;
3986         struct btrfs_device_info *devices_info = NULL;
3987         u64 total_avail;
3988         int num_stripes;        /* total number of stripes to allocate */
3989         int data_stripes;       /* number of stripes that count for
3990                                    block group size */
3991         int sub_stripes;        /* sub_stripes info for map */
3992         int dev_stripes;        /* stripes per dev */
3993         int devs_max;           /* max devs to use */
3994         int devs_min;           /* min devs needed */
3995         int devs_increment;     /* ndevs has to be a multiple of this */
3996         int ncopies;            /* how many copies to data has */
3997         int ret;
3998         u64 max_stripe_size;
3999         u64 max_chunk_size;
4000         u64 stripe_size;
4001         u64 num_bytes;
4002         u64 raid_stripe_len = BTRFS_STRIPE_LEN;
4003         int ndevs;
4004         int i;
4005         int j;
4006         int index;
4007 
4008         BUG_ON(!alloc_profile_is_valid(type, 0));
4009 
4010         if (list_empty(&fs_devices->alloc_list))
4011                 return -ENOSPC;
4012 
4013         index = __get_raid_index(type);
4014 
4015         sub_stripes = btrfs_raid_array[index].sub_stripes;
4016         dev_stripes = btrfs_raid_array[index].dev_stripes;
4017         devs_max = btrfs_raid_array[index].devs_max;
4018         devs_min = btrfs_raid_array[index].devs_min;
4019         devs_increment = btrfs_raid_array[index].devs_increment;
4020         ncopies = btrfs_raid_array[index].ncopies;
4021 
4022         if (type & BTRFS_BLOCK_GROUP_DATA) {
4023                 max_stripe_size = 1024 * 1024 * 1024;
4024                 max_chunk_size = 10 * max_stripe_size;
4025         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
4026                 /* for larger filesystems, use larger metadata chunks */
4027                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
4028                         max_stripe_size = 1024 * 1024 * 1024;
4029                 else
4030                         max_stripe_size = 256 * 1024 * 1024;
4031                 max_chunk_size = max_stripe_size;
4032         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
4033                 max_stripe_size = 32 * 1024 * 1024;
4034                 max_chunk_size = 2 * max_stripe_size;
4035         } else {
4036                 printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
4037                        type);
4038                 BUG_ON(1);
4039         }
4040 
4041         /* we don't want a chunk larger than 10% of writeable space */
4042         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
4043                              max_chunk_size);
4044 
4045         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
4046                                GFP_NOFS);
4047         if (!devices_info)
4048                 return -ENOMEM;
4049 
4050         cur = fs_devices->alloc_list.next;
4051 
4052         /*
4053          * in the first pass through the devices list, we gather information
4054          * about the available holes on each device.
4055          */
4056         ndevs = 0;
4057         while (cur != &fs_devices->alloc_list) {
4058                 struct btrfs_device *device;
4059                 u64 max_avail;
4060                 u64 dev_offset;
4061 
4062                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
4063 
4064                 cur = cur->next;
4065 
4066                 if (!device->writeable) {
4067                         WARN(1, KERN_ERR
4068                                "btrfs: read-only device in alloc_list\n");
4069                         continue;
4070                 }
4071 
4072                 if (!device->in_fs_metadata ||
4073                     device->is_tgtdev_for_dev_replace)
4074                         continue;
4075 
4076                 if (device->total_bytes > device->bytes_used)
4077                         total_avail = device->total_bytes - device->bytes_used;
4078                 else
4079                         total_avail = 0;
4080 
4081                 /* If there is no space on this device, skip it. */
4082                 if (total_avail == 0)
4083                         continue;
4084 
4085                 ret = find_free_dev_extent(trans, device,
4086                                            max_stripe_size * dev_stripes,
4087                                            &dev_offset, &max_avail);
4088                 if (ret && ret != -ENOSPC)
4089                         goto error;
4090 
4091                 if (ret == 0)
4092                         max_avail = max_stripe_size * dev_stripes;
4093 
4094                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
4095                         continue;
4096 
4097                 if (ndevs == fs_devices->rw_devices) {
4098                         WARN(1, "%s: found more than %llu devices\n",
4099                              __func__, fs_devices->rw_devices);
4100                         break;
4101                 }
4102                 devices_info[ndevs].dev_offset = dev_offset;
4103                 devices_info[ndevs].max_avail = max_avail;
4104                 devices_info[ndevs].total_avail = total_avail;
4105                 devices_info[ndevs].dev = device;
4106                 ++ndevs;
4107         }
4108 
4109         /*
4110          * now sort the devices by hole size / available space
4111          */
4112         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
4113              btrfs_cmp_device_info, NULL);
4114 
4115         /* round down to number of usable stripes */
4116         ndevs -= ndevs % devs_increment;
4117 
4118         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
4119                 ret = -ENOSPC;
4120                 goto error;
4121         }
4122 
4123         if (devs_max && ndevs > devs_max)
4124                 ndevs = devs_max;
4125         /*
4126          * the primary goal is to maximize the number of stripes, so use as many
4127          * devices as possible, even if the stripes are not maximum sized.
4128          */
4129         stripe_size = devices_info[ndevs-1].max_avail;
4130         num_stripes = ndevs * dev_stripes;
4131 
4132         /*
4133          * this will have to be fixed for RAID1 and RAID10 over
4134          * more drives
4135          */
4136         data_stripes = num_stripes / ncopies;
4137 
4138         if (type & BTRFS_BLOCK_GROUP_RAID5) {
4139                 raid_stripe_len = find_raid56_stripe_len(ndevs - 1,
4140                                  btrfs_super_stripesize(info->super_copy));
4141                 data_stripes = num_stripes - 1;
4142         }
4143         if (type & BTRFS_BLOCK_GROUP_RAID6) {
4144                 raid_stripe_len = find_raid56_stripe_len(ndevs - 2,
4145                                  btrfs_super_stripesize(info->super_copy));
4146                 data_stripes = num_stripes - 2;
4147         }
4148 
4149         /*
4150          * Use the number of data stripes to figure out how big this chunk
4151          * is really going to be in terms of logical address space,
4152          * and compare that answer with the max chunk size
4153          */
4154         if (stripe_size * data_stripes > max_chunk_size) {
4155                 u64 mask = (1ULL << 24) - 1;
4156                 stripe_size = max_chunk_size;
4157                 do_div(stripe_size, data_stripes);
4158 
4159                 /* bump the answer up to a 16MB boundary */
4160                 stripe_size = (stripe_size + mask) & ~mask;
4161 
4162                 /* but don't go higher than the limits we found
4163                  * while searching for free extents
4164                  */
4165                 if (stripe_size > devices_info[ndevs-1].max_avail)
4166                         stripe_size = devices_info[ndevs-1].max_avail;
4167         }
4168 
4169         do_div(stripe_size, dev_stripes);
4170 
4171         /* align to BTRFS_STRIPE_LEN */
4172         do_div(stripe_size, raid_stripe_len);
4173         stripe_size *= raid_stripe_len;
4174 
4175         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4176         if (!map) {
4177                 ret = -ENOMEM;
4178                 goto error;
4179         }
4180         map->num_stripes = num_stripes;
4181 
4182         for (i = 0; i < ndevs; ++i) {
4183                 for (j = 0; j < dev_stripes; ++j) {
4184                         int s = i * dev_stripes + j;
4185                         map->stripes[s].dev = devices_info[i].dev;
4186                         map->stripes[s].physical = devices_info[i].dev_offset +
4187                                                    j * stripe_size;
4188                 }
4189         }
4190         map->sector_size = extent_root->sectorsize;
4191         map->stripe_len = raid_stripe_len;
4192         map->io_align = raid_stripe_len;
4193         map->io_width = raid_stripe_len;
4194         map->type = type;
4195         map->sub_stripes = sub_stripes;
4196 
4197         num_bytes = stripe_size * data_stripes;
4198 
4199         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
4200 
4201         em = alloc_extent_map();
4202         if (!em) {
4203                 ret = -ENOMEM;
4204                 goto error;
4205         }
4206         em->bdev = (struct block_device *)map;
4207         em->start = start;
4208         em->len = num_bytes;
4209         em->block_start = 0;
4210         em->block_len = em->len;
4211         em->orig_block_len = stripe_size;
4212 
4213         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4214         write_lock(&em_tree->lock);
4215         ret = add_extent_mapping(em_tree, em, 0);
4216         if (!ret) {
4217                 list_add_tail(&em->list, &trans->transaction->pending_chunks);
4218                 atomic_inc(&em->refs);
4219         }
4220         write_unlock(&em_tree->lock);
4221         if (ret) {
4222                 free_extent_map(em);
4223                 goto error;
4224         }
4225 
4226         ret = btrfs_make_block_group(trans, extent_root, 0, type,
4227                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4228                                      start, num_bytes);
4229         if (ret)
4230                 goto error_del_extent;
4231 
4232         free_extent_map(em);
4233         check_raid56_incompat_flag(extent_root->fs_info, type);
4234 
4235         kfree(devices_info);
4236         return 0;
4237 
4238 error_del_extent:
4239         write_lock(&em_tree->lock);
4240         remove_extent_mapping(em_tree, em);
4241         write_unlock(&em_tree->lock);
4242 
4243         /* One for our allocation */
4244         free_extent_map(em);
4245         /* One for the tree reference */
4246         free_extent_map(em);
4247 error:
4248         kfree(map);
4249         kfree(devices_info);
4250         return ret;
4251 }
4252 
4253 int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
4254                                 struct btrfs_root *extent_root,
4255                                 u64 chunk_offset, u64 chunk_size)
4256 {
4257         struct btrfs_key key;
4258         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
4259         struct btrfs_device *device;
4260         struct btrfs_chunk *chunk;
4261         struct btrfs_stripe *stripe;
4262         struct extent_map_tree *em_tree;
4263         struct extent_map *em;
4264         struct map_lookup *map;
4265         size_t item_size;
4266         u64 dev_offset;
4267         u64 stripe_size;
4268         int i = 0;
4269         int ret;
4270 
4271         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4272         read_lock(&em_tree->lock);
4273         em = lookup_extent_mapping(em_tree, chunk_offset, chunk_size);
4274         read_unlock(&em_tree->lock);
4275 
4276         if (!em) {
4277                 btrfs_crit(extent_root->fs_info, "unable to find logical "
4278                            "%Lu len %Lu", chunk_offset, chunk_size);
4279                 return -EINVAL;
4280         }
4281 
4282         if (em->start != chunk_offset || em->len != chunk_size) {
4283                 btrfs_crit(extent_root->fs_info, "found a bad mapping, wanted"
4284                           " %Lu-%Lu, found %Lu-%Lu\n", chunk_offset,
4285                           chunk_size, em->start, em->len);
4286                 free_extent_map(em);
4287                 return -EINVAL;
4288         }
4289 
4290         map = (struct map_lookup *)em->bdev;
4291         item_size = btrfs_chunk_item_size(map->num_stripes);
4292         stripe_size = em->orig_block_len;
4293 
4294         chunk = kzalloc(item_size, GFP_NOFS);
4295         if (!chunk) {
4296                 ret = -ENOMEM;
4297                 goto out;
4298         }
4299 
4300         for (i = 0; i < map->num_stripes; i++) {
4301                 device = map->stripes[i].dev;
4302                 dev_offset = map->stripes[i].physical;
4303 
4304                 device->bytes_used += stripe_size;
4305                 ret = btrfs_update_device(trans, device);
4306                 if (ret)
4307                         goto out;
4308                 ret = btrfs_alloc_dev_extent(trans, device,
4309                                              chunk_root->root_key.objectid,
4310                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4311                                              chunk_offset, dev_offset,
4312                                              stripe_size);
4313                 if (ret)
4314                         goto out;
4315         }
4316 
4317         spin_lock(&extent_root->fs_info->free_chunk_lock);
4318         extent_root->fs_info->free_chunk_space -= (stripe_size *
4319                                                    map->num_stripes);
4320         spin_unlock(&extent_root->fs_info->free_chunk_lock);
4321 
4322         stripe = &chunk->stripe;
4323         for (i = 0; i < map->num_stripes; i++) {
4324                 device = map->stripes[i].dev;
4325                 dev_offset = map->stripes[i].physical;
4326 
4327                 btrfs_set_stack_stripe_devid(stripe, device->devid);
4328                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
4329                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
4330                 stripe++;
4331         }
4332 
4333         btrfs_set_stack_chunk_length(chunk, chunk_size);
4334         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
4335         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
4336         btrfs_set_stack_chunk_type(chunk, map->type);
4337         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
4338         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
4339         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
4340         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
4341         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
4342 
4343         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
4344         key.type = BTRFS_CHUNK_ITEM_KEY;
4345         key.offset = chunk_offset;
4346 
4347         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
4348         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
4349                 /*
4350                  * TODO: Cleanup of inserted chunk root in case of
4351                  * failure.
4352                  */
4353                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
4354                                              item_size);
4355         }
4356 
4357 out:
4358         kfree(chunk);
4359         free_extent_map(em);
4360         return ret;
4361 }
4362 
4363 /*
4364  * Chunk allocation falls into two parts. The first part does works
4365  * that make the new allocated chunk useable, but not do any operation
4366  * that modifies the chunk tree. The second part does the works that
4367  * require modifying the chunk tree. This division is important for the
4368  * bootstrap process of adding storage to a seed btrfs.
4369  */
4370 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4371                       struct btrfs_root *extent_root, u64 type)
4372 {
4373         u64 chunk_offset;
4374 
4375         chunk_offset = find_next_chunk(extent_root->fs_info);
4376         return __btrfs_alloc_chunk(trans, extent_root, chunk_offset, type);
4377 }
4378 
4379 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
4380                                          struct btrfs_root *root,
4381                                          struct btrfs_device *device)
4382 {
4383         u64 chunk_offset;
4384         u64 sys_chunk_offset;
4385         u64 alloc_profile;
4386         struct btrfs_fs_info *fs_info = root->fs_info;
4387         struct btrfs_root *extent_root = fs_info->extent_root;
4388         int ret;
4389 
4390         chunk_offset = find_next_chunk(fs_info);
4391         alloc_profile = btrfs_get_alloc_profile(extent_root, 0);
4392         ret = __btrfs_alloc_chunk(trans, extent_root, chunk_offset,
4393                                   alloc_profile);
4394         if (ret)
4395                 return ret;
4396 
4397         sys_chunk_offset = find_next_chunk(root->fs_info);
4398         alloc_profile = btrfs_get_alloc_profile(fs_info->chunk_root, 0);
4399         ret = __btrfs_alloc_chunk(trans, extent_root, sys_chunk_offset,
4400                                   alloc_profile);
4401         if (ret) {
4402                 btrfs_abort_transaction(trans, root, ret);
4403                 goto out;
4404         }
4405 
4406         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
4407         if (ret)
4408                 btrfs_abort_transaction(trans, root, ret);
4409 out:
4410         return ret;
4411 }
4412 
4413 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
4414 {
4415         struct extent_map *em;
4416         struct map_lookup *map;
4417         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4418         int readonly = 0;
4419         int i;
4420 
4421         read_lock(&map_tree->map_tree.lock);
4422         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
4423         read_unlock(&map_tree->map_tree.lock);
4424         if (!em)
4425                 return 1;
4426 
4427         if (btrfs_test_opt(root, DEGRADED)) {
4428                 free_extent_map(em);
4429                 return 0;
4430         }
4431 
4432         map = (struct map_lookup *)em->bdev;
4433         for (i = 0; i < map->num_stripes; i++) {
4434                 if (!map->stripes[i].dev->writeable) {
4435                         readonly = 1;
4436                         break;
4437                 }
4438         }
4439         free_extent_map(em);
4440         return readonly;
4441 }
4442 
4443 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
4444 {
4445         extent_map_tree_init(&tree->map_tree);
4446 }
4447 
4448 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
4449 {
4450         struct extent_map *em;
4451 
4452         while (1) {
4453                 write_lock(&tree->map_tree.lock);
4454                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
4455                 if (em)
4456                         remove_extent_mapping(&tree->map_tree, em);
4457                 write_unlock(&tree->map_tree.lock);
4458                 if (!em)
4459                         break;
4460                 kfree(em->bdev);
4461                 /* once for us */
4462                 free_extent_map(em);
4463                 /* once for the tree */
4464                 free_extent_map(em);
4465         }
4466 }
4467 
4468 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
4469 {
4470         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4471         struct extent_map *em;
4472         struct map_lookup *map;
4473         struct extent_map_tree *em_tree = &map_tree->map_tree;
4474         int ret;
4475 
4476         read_lock(&em_tree->lock);
4477         em = lookup_extent_mapping(em_tree, logical, len);
4478         read_unlock(&em_tree->lock);
4479 
4480         /*
4481          * We could return errors for these cases, but that could get ugly and
4482          * we'd probably do the same thing which is just not do anything else
4483          * and exit, so return 1 so the callers don't try to use other copies.
4484          */
4485         if (!em) {
4486                 btrfs_crit(fs_info, "No mapping for %Lu-%Lu\n", logical,
4487                             logical+len);
4488                 return 1;
4489         }
4490 
4491         if (em->start > logical || em->start + em->len < logical) {
4492                 btrfs_crit(fs_info, "Invalid mapping for %Lu-%Lu, got "
4493                             "%Lu-%Lu\n", logical, logical+len, em->start,
4494                             em->start + em->len);
4495                 free_extent_map(em);
4496                 return 1;
4497         }
4498 
4499         map = (struct map_lookup *)em->bdev;
4500         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
4501                 ret = map->num_stripes;
4502         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4503                 ret = map->sub_stripes;
4504         else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
4505                 ret = 2;
4506         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
4507                 ret = 3;
4508         else
4509                 ret = 1;
4510         free_extent_map(em);
4511 
4512         btrfs_dev_replace_lock(&fs_info->dev_replace);
4513         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
4514                 ret++;
4515         btrfs_dev_replace_unlock(&fs_info->dev_replace);
4516 
4517         return ret;
4518 }
4519 
4520 unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
4521                                     struct btrfs_mapping_tree *map_tree,
4522                                     u64 logical)
4523 {
4524         struct extent_map *em;
4525         struct map_lookup *map;
4526         struct extent_map_tree *em_tree = &map_tree->map_tree;
4527         unsigned long len = root->sectorsize;
4528 
4529         read_lock(&em_tree->lock);
4530         em = lookup_extent_mapping(em_tree, logical, len);
4531         read_unlock(&em_tree->lock);
4532         BUG_ON(!em);
4533 
4534         BUG_ON(em->start > logical || em->start + em->len < logical);
4535         map = (struct map_lookup *)em->bdev;
4536         if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4537                          BTRFS_BLOCK_GROUP_RAID6)) {
4538                 len = map->stripe_len * nr_data_stripes(map);
4539         }
4540         free_extent_map(em);
4541         return len;
4542 }
4543 
4544 int btrfs_is_parity_mirror(struct btrfs_mapping_tree *map_tree,
4545                            u64 logical, u64 len, int mirror_num)
4546 {
4547         struct extent_map *em;
4548         struct map_lookup *map;
4549         struct extent_map_tree *em_tree = &map_tree->map_tree;
4550         int ret = 0;
4551 
4552         read_lock(&em_tree->lock);
4553         em = lookup_extent_mapping(em_tree, logical, len);
4554         read_unlock(&em_tree->lock);
4555         BUG_ON(!em);
4556 
4557         BUG_ON(em->start > logical || em->start + em->len < logical);
4558         map = (struct map_lookup *)em->bdev;
4559         if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4560                          BTRFS_BLOCK_GROUP_RAID6))
4561                 ret = 1;
4562         free_extent_map(em);
4563         return ret;
4564 }
4565 
4566 static int find_live_mirror(struct btrfs_fs_info *fs_info,
4567                             struct map_lookup *map, int first, int num,
4568                             int optimal, int dev_replace_is_ongoing)
4569 {
4570         int i;
4571         int tolerance;
4572         struct btrfs_device *srcdev;
4573 
4574         if (dev_replace_is_ongoing &&
4575             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
4576              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
4577                 srcdev = fs_info->dev_replace.srcdev;
4578         else
4579                 srcdev = NULL;
4580 
4581         /*
4582          * try to avoid the drive that is the source drive for a
4583          * dev-replace procedure, only choose it if no other non-missing
4584          * mirror is available
4585          */
4586         for (tolerance = 0; tolerance < 2; tolerance++) {
4587                 if (map->stripes[optimal].dev->bdev &&
4588                     (tolerance || map->stripes[optimal].dev != srcdev))
4589                         return optimal;
4590                 for (i = first; i < first + num; i++) {
4591                         if (map->stripes[i].dev->bdev &&
4592                             (tolerance || map->stripes[i].dev != srcdev))
4593                                 return i;
4594                 }
4595         }
4596 
4597         /* we couldn't find one that doesn't fail.  Just return something
4598          * and the io error handling code will clean up eventually
4599          */
4600         return optimal;
4601 }
4602 
4603 static inline int parity_smaller(u64 a, u64 b)
4604 {
4605         return a > b;
4606 }
4607 
4608 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
4609 static void sort_parity_stripes(struct btrfs_bio *bbio, u64 *raid_map)
4610 {
4611         struct btrfs_bio_stripe s;
4612         int i;
4613         u64 l;
4614         int again = 1;
4615 
4616         while (again) {
4617                 again = 0;
4618                 for (i = 0; i < bbio->num_stripes - 1; i++) {
4619                         if (parity_smaller(raid_map[i], raid_map[i+1])) {
4620                                 s = bbio->stripes[i];
4621                                 l = raid_map[i];
4622                                 bbio->stripes[i] = bbio->stripes[i+1];
4623                                 raid_map[i] = raid_map[i+1];
4624                                 bbio->stripes[i+1] = s;
4625                                 raid_map[i+1] = l;
4626                                 again = 1;
4627                         }
4628                 }
4629         }
4630 }
4631 
4632 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
4633                              u64 logical, u64 *length,
4634                              struct btrfs_bio **bbio_ret,
4635                              int mirror_num, u64 **raid_map_ret)
4636 {
4637         struct extent_map *em;
4638         struct map_lookup *map;
4639         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
4640         struct extent_map_tree *em_tree = &map_tree->map_tree;
4641         u64 offset;
4642         u64 stripe_offset;
4643         u64 stripe_end_offset;
4644         u64 stripe_nr;
4645         u64 stripe_nr_orig;
4646         u64 stripe_nr_end;
4647         u64 stripe_len;
4648         u64 *raid_map = NULL;
4649         int stripe_index;
4650         int i;
4651         int ret = 0;
4652         int num_stripes;
4653         int max_errors = 0;
4654         struct btrfs_bio *bbio = NULL;
4655         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
4656         int dev_replace_is_ongoing = 0;
4657         int num_alloc_stripes;
4658         int patch_the_first_stripe_for_dev_replace = 0;
4659         u64 physical_to_patch_in_first_stripe = 0;
4660         u64 raid56_full_stripe_start = (u64)-1;
4661 
4662         read_lock(&em_tree->lock);
4663         em = lookup_extent_mapping(em_tree, logical, *length);
4664         read_unlock(&em_tree->lock);
4665 
4666         if (!em) {
4667                 btrfs_crit(fs_info, "unable to find logical %llu len %llu",
4668                         logical, *length);
4669                 return -EINVAL;
4670         }
4671 
4672         if (em->start > logical || em->start + em->len < logical) {
4673                 btrfs_crit(fs_info, "found a bad mapping, wanted %Lu, "
4674                            "found %Lu-%Lu\n", logical, em->start,
4675                            em->start + em->len);
4676                 free_extent_map(em);
4677                 return -EINVAL;
4678         }
4679 
4680         map = (struct map_lookup *)em->bdev;
4681         offset = logical - em->start;
4682 
4683         stripe_len = map->stripe_len;
4684         stripe_nr = offset;
4685         /*
4686          * stripe_nr counts the total number of stripes we have to stride
4687          * to get to this block
4688          */
4689         do_div(stripe_nr, stripe_len);
4690 
4691         stripe_offset = stripe_nr * stripe_len;
4692         BUG_ON(offset < stripe_offset);
4693 
4694         /* stripe_offset is the offset of this block in its stripe*/
4695         stripe_offset = offset - stripe_offset;
4696 
4697         /* if we're here for raid56, we need to know the stripe aligned start */
4698         if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)) {
4699                 unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
4700                 raid56_full_stripe_start = offset;
4701 
4702                 /* allow a write of a full stripe, but make sure we don't
4703                  * allow straddling of stripes
4704                  */
4705                 do_div(raid56_full_stripe_start, full_stripe_len);
4706                 raid56_full_stripe_start *= full_stripe_len;
4707         }
4708 
4709         if (rw & REQ_DISCARD) {
4710                 /* we don't discard raid56 yet */
4711                 if (map->type &
4712                     (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)) {
4713                         ret = -EOPNOTSUPP;
4714                         goto out;
4715                 }
4716                 *length = min_t(u64, em->len - offset, *length);
4717         } else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
4718                 u64 max_len;
4719                 /* For writes to RAID[56], allow a full stripeset across all disks.
4720                    For other RAID types and for RAID[56] reads, just allow a single
4721                    stripe (on a single disk). */
4722                 if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6) &&
4723                     (rw & REQ_WRITE)) {
4724                         max_len = stripe_len * nr_data_stripes(map) -
4725                                 (offset - raid56_full_stripe_start);
4726                 } else {
4727                         /* we limit the length of each bio to what fits in a stripe */
4728                         max_len = stripe_len - stripe_offset;
4729                 }
4730                 *length = min_t(u64, em->len - offset, max_len);
4731         } else {
4732                 *length = em->len - offset;
4733         }
4734 
4735         /* This is for when we're called from btrfs_merge_bio_hook() and all
4736            it cares about is the length */
4737         if (!bbio_ret)
4738                 goto out;
4739 
4740         btrfs_dev_replace_lock(dev_replace);
4741         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
4742         if (!dev_replace_is_ongoing)
4743                 btrfs_dev_replace_unlock(dev_replace);
4744 
4745         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
4746             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
4747             dev_replace->tgtdev != NULL) {
4748                 /*
4749                  * in dev-replace case, for repair case (that's the only
4750                  * case where the mirror is selected explicitly when
4751                  * calling btrfs_map_block), blocks left of the left cursor
4752                  * can also be read from the target drive.
4753                  * For REQ_GET_READ_MIRRORS, the target drive is added as
4754                  * the last one to the array of stripes. For READ, it also
4755                  * needs to be supported using the same mirror number.
4756                  * If the requested block is not left of the left cursor,
4757                  * EIO is returned. This can happen because btrfs_num_copies()
4758                  * returns one more in the dev-replace case.
4759                  */
4760                 u64 tmp_length = *length;
4761                 struct btrfs_bio *tmp_bbio = NULL;
4762                 int tmp_num_stripes;
4763                 u64 srcdev_devid = dev_replace->srcdev->devid;
4764                 int index_srcdev = 0;
4765                 int found = 0;
4766                 u64 physical_of_found = 0;
4767 
4768                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
4769                              logical, &tmp_length, &tmp_bbio, 0, NULL);
4770                 if (ret) {
4771                         WARN_ON(tmp_bbio != NULL);
4772                         goto out;
4773                 }
4774 
4775                 tmp_num_stripes = tmp_bbio->num_stripes;
4776                 if (mirror_num > tmp_num_stripes) {
4777                         /*
4778                          * REQ_GET_READ_MIRRORS does not contain this
4779                          * mirror, that means that the requested area
4780                          * is not left of the left cursor
4781                          */
4782                         ret = -EIO;
4783                         kfree(tmp_bbio);
4784                         goto out;
4785                 }
4786 
4787                 /*
4788                  * process the rest of the function using the mirror_num
4789                  * of the source drive. Therefore look it up first.
4790                  * At the end, patch the device pointer to the one of the
4791                  * target drive.
4792                  */
4793                 for (i = 0; i < tmp_num_stripes; i++) {
4794                         if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) {
4795                                 /*
4796                                  * In case of DUP, in order to keep it
4797                                  * simple, only add the mirror with the
4798                                  * lowest physical address
4799                                  */
4800                                 if (found &&
4801                                     physical_of_found <=
4802                                      tmp_bbio->stripes[i].physical)
4803                                         continue;
4804                                 index_srcdev = i;
4805                                 found = 1;
4806                                 physical_of_found =
4807                                         tmp_bbio->stripes[i].physical;
4808                         }
4809                 }
4810 
4811                 if (found) {
4812                         mirror_num = index_srcdev + 1;
4813                         patch_the_first_stripe_for_dev_replace = 1;
4814                         physical_to_patch_in_first_stripe = physical_of_found;
4815                 } else {
4816                         WARN_ON(1);
4817                         ret = -EIO;
4818                         kfree(tmp_bbio);
4819                         goto out;
4820                 }
4821 
4822                 kfree(tmp_bbio);
4823         } else if (mirror_num > map->num_stripes) {
4824                 mirror_num = 0;
4825         }
4826 
4827         num_stripes = 1;
4828         stripe_index = 0;
4829         stripe_nr_orig = stripe_nr;
4830         stripe_nr_end = ALIGN(offset + *length, map->stripe_len);
4831         do_div(stripe_nr_end, map->stripe_len);
4832         stripe_end_offset = stripe_nr_end * map->stripe_len -
4833                             (offset + *length);
4834 
4835         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4836                 if (rw & REQ_DISCARD)
4837                         num_stripes = min_t(u64, map->num_stripes,
4838                                             stripe_nr_end - stripe_nr_orig);
4839                 stripe_index = do_div(stripe_nr, map->num_stripes);
4840         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
4841                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
4842                         num_stripes = map->num_stripes;
4843                 else if (mirror_num)
4844                         stripe_index = mirror_num - 1;
4845                 else {
4846                         stripe_index = find_live_mirror(fs_info, map, 0,
4847                                             map->num_stripes,
4848                                             current->pid % map->num_stripes,
4849                                             dev_replace_is_ongoing);
4850                         mirror_num = stripe_index + 1;
4851                 }
4852 
4853         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
4854                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
4855                         num_stripes = map->num_stripes;
4856                 } else if (mirror_num) {
4857                         stripe_index = mirror_num - 1;
4858                 } else {
4859                         mirror_num = 1;
4860                 }
4861 
4862         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4863                 int factor = map->num_stripes / map->sub_stripes;
4864 
4865                 stripe_index = do_div(stripe_nr, factor);
4866                 stripe_index *= map->sub_stripes;
4867 
4868                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
4869                         num_stripes = map->sub_stripes;
4870                 else if (rw & REQ_DISCARD)
4871                         num_stripes = min_t(u64, map->sub_stripes *
4872                                             (stripe_nr_end - stripe_nr_orig),
4873                                             map->num_stripes);
4874                 else if (mirror_num)
4875                         stripe_index += mirror_num - 1;
4876                 else {
4877                         int old_stripe_index = stripe_index;
4878                         stripe_index = find_live_mirror(fs_info, map,
4879                                               stripe_index,
4880                                               map->sub_stripes, stripe_index +
4881                                               current->pid % map->sub_stripes,
4882                                               dev_replace_is_ongoing);
4883                         mirror_num = stripe_index - old_stripe_index + 1;
4884                 }
4885 
4886         } else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
4887                                 BTRFS_BLOCK_GROUP_RAID6)) {
4888                 u64 tmp;
4889 
4890                 if (bbio_ret && ((rw & REQ_WRITE) || mirror_num > 1)
4891                     && raid_map_ret) {
4892                         int i, rot;
4893 
4894                         /* push stripe_nr back to the start of the full stripe */
4895                         stripe_nr = raid56_full_stripe_start;
4896                         do_div(stripe_nr, stripe_len);
4897 
4898                         stripe_index = do_div(stripe_nr, nr_data_stripes(map));
4899 
4900                         /* RAID[56] write or recovery. Return all stripes */
4901                         num_stripes = map->num_stripes;
4902                         max_errors = nr_parity_stripes(map);
4903 
4904                         raid_map = kmalloc_array(num_stripes, sizeof(u64),
4905                                            GFP_NOFS);
4906                         if (!raid_map) {
4907                                 ret = -ENOMEM;
4908                                 goto out;
4909                         }
4910 
4911                         /* Work out the disk rotation on this stripe-set */
4912                         tmp = stripe_nr;
4913                         rot = do_div(tmp, num_stripes);
4914 
4915                         /* Fill in the logical address of each stripe */
4916                         tmp = stripe_nr * nr_data_stripes(map);
4917                         for (i = 0; i < nr_data_stripes(map); i++)
4918                                 raid_map[(i+rot) % num_stripes] =
4919                                         em->start + (tmp + i) * map->stripe_len;
4920 
4921                         raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
4922                         if (map->type & BTRFS_BLOCK_GROUP_RAID6)
4923                                 raid_map[(i+rot+1) % num_stripes] =
4924                                         RAID6_Q_STRIPE;
4925 
4926                         *length = map->stripe_len;
4927                         stripe_index = 0;
4928                         stripe_offset = 0;
4929                 } else {
4930                         /*
4931                          * Mirror #0 or #1 means the original data block.
4932                          * Mirror #2 is RAID5 parity block.
4933                          * Mirror #3 is RAID6 Q block.
4934                          */
4935                         stripe_index = do_div(stripe_nr, nr_data_stripes(map));
4936                         if (mirror_num > 1)
4937                                 stripe_index = nr_data_stripes(map) +
4938                                                 mirror_num - 2;
4939 
4940                         /* We distribute the parity blocks across stripes */
4941                         tmp = stripe_nr + stripe_index;
4942                         stripe_index = do_div(tmp, map->num_stripes);
4943                 }
4944         } else {
4945                 /*
4946                  * after this do_div call, stripe_nr is the number of stripes
4947                  * on this device we have to walk to find the data, and
4948                  * stripe_index is the number of our device in the stripe array
4949                  */
4950                 stripe_index = do_div(stripe_nr, map->num_stripes);
4951                 mirror_num = stripe_index + 1;
4952         }
4953         BUG_ON(stripe_index >= map->num_stripes);
4954 
4955         num_alloc_stripes = num_stripes;
4956         if (dev_replace_is_ongoing) {
4957                 if (rw & (REQ_WRITE | REQ_DISCARD))
4958                         num_alloc_stripes <<= 1;
4959                 if (rw & REQ_GET_READ_MIRRORS)
4960                         num_alloc_stripes++;
4961         }
4962         bbio = kzalloc(btrfs_bio_size(num_alloc_stripes), GFP_NOFS);
4963         if (!bbio) {
4964                 kfree(raid_map);
4965                 ret = -ENOMEM;
4966                 goto out;
4967         }
4968         atomic_set(&bbio->error, 0);
4969 
4970         if (rw & REQ_DISCARD) {
4971                 int factor = 0;
4972                 int sub_stripes = 0;
4973                 u64 stripes_per_dev = 0;
4974                 u32 remaining_stripes = 0;
4975                 u32 last_stripe = 0;
4976 
4977                 if (map->type &
4978                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
4979                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4980                                 sub_stripes = 1;
4981                         else
4982                                 sub_stripes = map->sub_stripes;
4983 
4984                         factor = map->num_stripes / sub_stripes;
4985                         stripes_per_dev = div_u64_rem(stripe_nr_end -
4986                                                       stripe_nr_orig,
4987                                                       factor,
4988                                                       &remaining_stripes);
4989                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
4990                         last_stripe *= sub_stripes;
4991                 }
4992 
4993                 for (i = 0; i < num_stripes; i++) {
4994                         bbio->stripes[i].physical =
4995                                 map->stripes[stripe_index].physical +
4996                                 stripe_offset + stripe_nr * map->stripe_len;
4997                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
4998 
4999                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
5000                                          BTRFS_BLOCK_GROUP_RAID10)) {
5001                                 bbio->stripes[i].length = stripes_per_dev *
5002                                                           map->stripe_len;
5003 
5004                                 if (i / sub_stripes < remaining_stripes)
5005                                         bbio->stripes[i].length +=
5006                                                 map->stripe_len;
5007 
5008                                 /*
5009                                  * Special for the first stripe and
5010                                  * the last stripe:
5011                                  *
5012                                  * |-------|...|-------|
5013                                  *     |----------|
5014                                  *    off     end_off
5015                                  */
5016                                 if (i < sub_stripes)
5017                                         bbio->stripes[i].length -=
5018                                                 stripe_offset;
5019 
5020                                 if (stripe_index >= last_stripe &&
5021                                     stripe_index <= (last_stripe +
5022                                                      sub_stripes - 1))
5023                                         bbio->stripes[i].length -=
5024                                                 stripe_end_offset;
5025 
5026                                 if (i == sub_stripes - 1)
5027                                         stripe_offset = 0;
5028                         } else
5029                                 bbio->stripes[i].length = *length;
5030 
5031                         stripe_index++;
5032                         if (stripe_index == map->num_stripes) {
5033                                 /* This could only happen for RAID0/10 */
5034                                 stripe_index = 0;
5035                                 stripe_nr++;
5036                         }
5037                 }
5038         } else {
5039                 for (i = 0; i < num_stripes; i++) {
5040                         bbio->stripes[i].physical =
5041                                 map->stripes[stripe_index].physical +
5042                                 stripe_offset +
5043                                 stripe_nr * map->stripe_len;
5044                         bbio->stripes[i].dev =
5045                                 map->stripes[stripe_index].dev;
5046                         stripe_index++;
5047                 }
5048         }
5049 
5050         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) {
5051                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
5052                                  BTRFS_BLOCK_GROUP_RAID10 |
5053                                  BTRFS_BLOCK_GROUP_RAID5 |
5054                                  BTRFS_BLOCK_GROUP_DUP)) {
5055                         max_errors = 1;
5056                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) {
5057                         max_errors = 2;
5058                 }
5059         }
5060 
5061         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
5062             dev_replace->tgtdev != NULL) {
5063                 int index_where_to_add;
5064                 u64 srcdev_devid = dev_replace->srcdev->devid;
5065 
5066                 /*
5067                  * duplicate the write operations while the dev replace
5068                  * procedure is running. Since the copying of the old disk
5069                  * to the new disk takes place at run time while the
5070                  * filesystem is mounted writable, the regular write
5071                  * operations to the old disk have to be duplicated to go
5072                  * to the new disk as well.
5073                  * Note that device->missing is handled by the caller, and
5074                  * that the write to the old disk is already set up in the
5075                  * stripes array.
5076                  */
5077                 index_where_to_add = num_stripes;
5078                 for (i = 0; i < num_stripes; i++) {
5079                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5080                                 /* write to new disk, too */
5081                                 struct btrfs_bio_stripe *new =
5082                                         bbio->stripes + index_where_to_add;
5083                                 struct btrfs_bio_stripe *old =
5084                                         bbio->stripes + i;
5085 
5086                                 new->physical = old->physical;
5087                                 new->length = old->length;
5088                                 new->dev = dev_replace->tgtdev;
5089                                 index_where_to_add++;
5090                                 max_errors++;
5091                         }
5092                 }
5093                 num_stripes = index_where_to_add;
5094         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
5095                    dev_replace->tgtdev != NULL) {
5096                 u64 srcdev_devid = dev_replace->srcdev->devid;
5097                 int index_srcdev = 0;
5098                 int found = 0;
5099                 u64 physical_of_found = 0;
5100 
5101                 /*
5102                  * During the dev-replace procedure, the target drive can
5103                  * also be used to read data in case it is needed to repair
5104                  * a corrupt block elsewhere. This is possible if the
5105                  * requested area is left of the left cursor. In this area,
5106                  * the target drive is a full copy of the source drive.
5107                  */
5108                 for (i = 0; i < num_stripes; i++) {
5109                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5110                                 /*
5111                                  * In case of DUP, in order to keep it
5112                                  * simple, only add the mirror with the
5113                                  * lowest physical address
5114                                  */
5115                                 if (found &&
5116                                     physical_of_found <=
5117                                      bbio->stripes[i].physical)
5118                                         continue;
5119                                 index_srcdev = i;
5120                                 found = 1;
5121                                 physical_of_found = bbio->stripes[i].physical;
5122                         }
5123                 }
5124                 if (found) {
5125                         u64 length = map->stripe_len;
5126 
5127                         if (physical_of_found + length <=
5128                             dev_replace->cursor_left) {
5129                                 struct btrfs_bio_stripe *tgtdev_stripe =
5130                                         bbio->stripes + num_stripes;
5131 
5132                                 tgtdev_stripe->physical = physical_of_found;
5133                                 tgtdev_stripe->length =
5134                                         bbio->stripes[index_srcdev].length;
5135                                 tgtdev_stripe->dev = dev_replace->tgtdev;
5136 
5137                                 num_stripes++;
5138                         }
5139                 }
5140         }
5141 
5142         *bbio_ret = bbio;
5143         bbio->num_stripes = num_stripes;
5144         bbio->max_errors = max_errors;
5145         bbio->mirror_num = mirror_num;
5146 
5147         /*
5148          * this is the case that REQ_READ && dev_replace_is_ongoing &&
5149          * mirror_num == num_stripes + 1 && dev_replace target drive is
5150          * available as a mirror
5151          */
5152         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
5153                 WARN_ON(num_stripes > 1);
5154                 bbio->stripes[0].dev = dev_replace->tgtdev;
5155                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
5156                 bbio->mirror_num = map->num_stripes + 1;
5157         }
5158         if (raid_map) {
5159                 sort_parity_stripes(bbio, raid_map);
5160                 *raid_map_ret = raid_map;
5161         }
5162 out:
5163         if (dev_replace_is_ongoing)
5164                 btrfs_dev_replace_unlock(dev_replace);
5165         free_extent_map(em);
5166         return ret;
5167 }
5168 
5169 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5170                       u64 logical, u64 *length,
5171                       struct btrfs_bio **bbio_ret, int mirror_num)
5172 {
5173         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5174                                  mirror_num, NULL);
5175 }
5176 
5177 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
5178                      u64 chunk_start, u64 physical, u64 devid,
5179                      u64 **logical, int *naddrs, int *stripe_len)
5180 {
5181         struct extent_map_tree *em_tree = &map_tree->map_tree;
5182         struct extent_map *em;
5183         struct map_lookup *map;
5184         u64 *buf;
5185         u64 bytenr;
5186         u64 length;
5187         u64 stripe_nr;
5188         u64 rmap_len;
5189         int i, j, nr = 0;
5190 
5191         read_lock(&em_tree->lock);
5192         em = lookup_extent_mapping(em_tree, chunk_start, 1);
5193         read_unlock(&em_tree->lock);
5194 
5195         if (!em) {
5196                 printk(KERN_ERR "btrfs: couldn't find em for chunk %Lu\n",
5197                        chunk_start);
5198                 return -EIO;
5199         }
5200 
5201         if (em->start != chunk_start) {
5202                 printk(KERN_ERR "btrfs: bad chunk start, em=%Lu, wanted=%Lu\n",
5203                        em->start, chunk_start);
5204                 free_extent_map(em);
5205                 return -EIO;
5206         }
5207         map = (struct map_lookup *)em->bdev;
5208 
5209         length = em->len;
5210         rmap_len = map->stripe_len;
5211 
5212         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5213                 do_div(length, map->num_stripes / map->sub_stripes);
5214         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5215                 do_div(length, map->num_stripes);
5216         else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
5217                               BTRFS_BLOCK_GROUP_RAID6)) {
5218                 do_div(length, nr_data_stripes(map));
5219                 rmap_len = map->stripe_len * nr_data_stripes(map);
5220         }
5221 
5222         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
5223         BUG_ON(!buf); /* -ENOMEM */
5224 
5225         for (i = 0; i < map->num_stripes; i++) {
5226                 if (devid && map->stripes[i].dev->devid != devid)
5227                         continue;
5228                 if (map->stripes[i].physical > physical ||
5229                     map->stripes[i].physical + length <= physical)
5230                         continue;
5231 
5232                 stripe_nr = physical - map->stripes[i].physical;
5233                 do_div(stripe_nr, map->stripe_len);
5234 
5235                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5236                         stripe_nr = stripe_nr * map->num_stripes + i;
5237                         do_div(stripe_nr, map->sub_stripes);
5238                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5239                         stripe_nr = stripe_nr * map->num_stripes + i;
5240                 } /* else if RAID[56], multiply by nr_data_stripes().
5241                    * Alternatively, just use rmap_len below instead of
5242                    * map->stripe_len */
5243 
5244                 bytenr = chunk_start + stripe_nr * rmap_len;
5245                 WARN_ON(nr >= map->num_stripes);
5246                 for (j = 0; j < nr; j++) {
5247                         if (buf[j] == bytenr)
5248                                 break;
5249                 }
5250                 if (j == nr) {
5251                         WARN_ON(nr >= map->num_stripes);
5252                         buf[nr++] = bytenr;
5253                 }
5254         }
5255 
5256         *logical = buf;
5257         *naddrs = nr;
5258         *stripe_len = rmap_len;
5259 
5260         free_extent_map(em);
5261         return 0;
5262 }
5263 
5264 static void btrfs_end_bio(struct bio *bio, int err)
5265 {
5266         struct btrfs_bio *bbio = bio->bi_private;
5267         int is_orig_bio = 0;
5268 
5269         if (err) {
5270                 atomic_inc(&bbio->error);
5271                 if (err == -EIO || err == -EREMOTEIO) {
5272                         unsigned int stripe_index =
5273                                 btrfs_io_bio(bio)->stripe_index;
5274                         struct btrfs_device *dev;
5275 
5276                         BUG_ON(stripe_index >= bbio->num_stripes);
5277                         dev = bbio->stripes[stripe_index].dev;
5278                         if (dev->bdev) {
5279                                 if (bio->bi_rw & WRITE)
5280                                         btrfs_dev_stat_inc(dev,
5281                                                 BTRFS_DEV_STAT_WRITE_ERRS);
5282                                 else
5283                                         btrfs_dev_stat_inc(dev,
5284                                                 BTRFS_DEV_STAT_READ_ERRS);
5285                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
5286                                         btrfs_dev_stat_inc(dev,
5287                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
5288                                 btrfs_dev_stat_print_on_error(dev);
5289                         }
5290                 }
5291         }
5292 
5293         if (bio == bbio->orig_bio)
5294                 is_orig_bio = 1;
5295 
5296         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5297                 if (!is_orig_bio) {
5298                         bio_put(bio);
5299                         bio = bbio->orig_bio;
5300                 }
5301                 bio->bi_private = bbio->private;
5302                 bio->bi_end_io = bbio->end_io;
5303                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
5304                 /* only send an error to the higher layers if it is
5305                  * beyond the tolerance of the btrfs bio
5306                  */
5307                 if (atomic_read(&bbio->error) > bbio->max_errors) {
5308                         err = -EIO;
5309                 } else {
5310                         /*
5311                          * this bio is actually up to date, we didn't
5312                          * go over the max number of errors
5313                          */
5314                         set_bit(BIO_UPTODATE, &bio->bi_flags);
5315                         err = 0;
5316                 }
5317                 kfree(bbio);
5318 
5319                 bio_endio(bio, err);
5320         } else if (!is_orig_bio) {
5321                 bio_put(bio);
5322         }
5323 }
5324 
5325 struct async_sched {
5326         struct bio *bio;
5327         int rw;
5328         struct btrfs_fs_info *info;
5329         struct btrfs_work work;
5330 };
5331 
5332 /*
5333  * see run_scheduled_bios for a description of why bios are collected for
5334  * async submit.
5335  *
5336  * This will add one bio to the pending list for a device and make sure
5337  * the work struct is scheduled.
5338  */
5339 static noinline void btrfs_schedule_bio(struct btrfs_root *root,
5340                                         struct btrfs_device *device,
5341                                         int rw, struct bio *bio)
5342 {
5343         int should_queue = 1;
5344         struct btrfs_pending_bios *pending_bios;
5345 
5346         if (device->missing || !device->bdev) {
5347                 bio_endio(bio, -EIO);
5348                 return;
5349         }
5350 
5351         /* don't bother with additional async steps for reads, right now */
5352         if (!(rw & REQ_WRITE)) {
5353                 bio_get(bio);
5354                 btrfsic_submit_bio(rw, bio);
5355                 bio_put(bio);
5356                 return;
5357         }
5358 
5359         /*
5360          * nr_async_bios allows us to reliably return congestion to the
5361          * higher layers.  Otherwise, the async bio makes it appear we have
5362          * made progress against dirty pages when we've really just put it
5363          * on a queue for later
5364          */
5365         atomic_inc(&root->fs_info->nr_async_bios);
5366         WARN_ON(bio->bi_next);
5367         bio->bi_next = NULL;
5368         bio->bi_rw |= rw;
5369 
5370         spin_lock(&device->io_lock);
5371         if (bio->bi_rw & REQ_SYNC)
5372                 pending_bios = &device->pending_sync_bios;
5373         else
5374                 pending_bios = &device->pending_bios;
5375 
5376         if (pending_bios->tail)
5377                 pending_bios->tail->bi_next = bio;
5378 
5379         pending_bios->tail = bio;
5380         if (!pending_bios->head)
5381                 pending_bios->head = bio;
5382         if (device->running_pending)
5383                 should_queue = 0;
5384 
5385         spin_unlock(&device->io_lock);
5386 
5387         if (should_queue)
5388                 btrfs_queue_worker(&root->fs_info->submit_workers,
5389                                    &device->work);
5390 }
5391 
5392 static int bio_size_ok(struct block_device *bdev, struct bio *bio,
5393                        sector_t sector)
5394 {
5395         struct bio_vec *prev;
5396         struct request_queue *q = bdev_get_queue(bdev);
5397         unsigned int max_sectors = queue_max_sectors(q);
5398         struct bvec_merge_data bvm = {
5399                 .bi_bdev = bdev,
5400                 .bi_sector = sector,
5401                 .bi_rw = bio->bi_rw,
5402         };
5403 
5404         if (WARN_ON(bio->bi_vcnt == 0))
5405                 return 1;
5406 
5407         prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
5408         if (bio_sectors(bio) > max_sectors)
5409                 return 0;
5410 
5411         if (!q->merge_bvec_fn)
5412                 return 1;
5413 
5414         bvm.bi_size = bio->bi_size - prev->bv_len;
5415         if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len)
5416                 return 0;
5417         return 1;
5418 }
5419 
5420 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
5421                               struct bio *bio, u64 physical, int dev_nr,
5422                               int rw, int async)
5423 {
5424         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
5425 
5426         bio->bi_private = bbio;
5427         btrfs_io_bio(bio)->stripe_index = dev_nr;
5428         bio->bi_end_io = btrfs_end_bio;
5429         bio->bi_sector = physical >> 9;
5430 #ifdef DEBUG
5431         {
5432                 struct rcu_string *name;
5433 
5434                 rcu_read_lock();
5435                 name = rcu_dereference(dev->name);
5436                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
5437                          "(%s id %llu), size=%u\n", rw,
5438                          (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
5439                          name->str, dev->devid, bio->bi_size);
5440                 rcu_read_unlock();
5441         }
5442 #endif
5443         bio->bi_bdev = dev->bdev;
5444         if (async)
5445                 btrfs_schedule_bio(root, dev, rw, bio);
5446         else
5447                 btrfsic_submit_bio(rw, bio);
5448 }
5449 
5450 static int breakup_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
5451                               struct bio *first_bio, struct btrfs_device *dev,
5452                               int dev_nr, int rw, int async)
5453 {
5454         struct bio_vec *bvec = first_bio->bi_io_vec;
5455         struct bio *bio;
5456         int nr_vecs = bio_get_nr_vecs(dev->bdev);
5457         u64 physical = bbio->stripes[dev_nr].physical;
5458 
5459 again:
5460         bio = btrfs_bio_alloc(dev->bdev, physical >> 9, nr_vecs, GFP_NOFS);
5461         if (!bio)
5462                 return -ENOMEM;
5463 
5464         while (bvec <= (first_bio->bi_io_vec + first_bio->bi_vcnt - 1)) {
5465                 if (bio_add_page(bio, bvec->bv_page, bvec->bv_len,
5466                                  bvec->bv_offset) < bvec->bv_len) {
5467                         u64 len = bio->bi_size;
5468 
5469                         atomic_inc(&bbio->stripes_pending);
5470                         submit_stripe_bio(root, bbio, bio, physical, dev_nr,
5471                                           rw, async);
5472                         physical += len;
5473                         goto again;
5474                 }
5475                 bvec++;
5476         }
5477 
5478         submit_stripe_bio(root, bbio, bio, physical, dev_nr, rw, async);
5479         return 0;
5480 }
5481 
5482 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
5483 {
5484         atomic_inc(&bbio->error);
5485         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5486                 bio->bi_private = bbio->private;
5487                 bio->bi_end_io = bbio->end_io;
5488                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
5489                 bio->bi_sector = logical >> 9;
5490                 kfree(bbio);
5491                 bio_endio(bio, -EIO);
5492         }
5493 }
5494 
5495 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
5496                   int mirror_num, int async_submit)
5497 {
5498         struct btrfs_device *dev;
5499         struct bio *first_bio = bio;
5500         u64 logical = (u64)bio->bi_sector << 9;
5501         u64 length = 0;
5502         u64 map_length;
5503         u64 *raid_map = NULL;
5504         int ret;
5505         int dev_nr = 0;
5506         int total_devs = 1;
5507         struct btrfs_bio *bbio = NULL;
5508 
5509         length = bio->bi_size;
5510         map_length = length;
5511 
5512         ret = __btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
5513                               mirror_num, &raid_map);
5514         if (ret) /* -ENOMEM */
5515                 return ret;
5516 
5517         total_devs = bbio->num_stripes;
5518         bbio->orig_bio = first_bio;
5519         bbio->private = first_bio->bi_private;
5520         bbio->end_io = first_bio->bi_end_io;
5521         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
5522 
5523         if (raid_map) {
5524                 /* In this case, map_length has been set to the length of
5525                    a single stripe; not the whole write */
5526                 if (rw & WRITE) {
5527                         return raid56_parity_write(root, bio, bbio,
5528                                                    raid_map, map_length);
5529                 } else {
5530                         return raid56_parity_recover(root, bio, bbio,
5531                                                      raid_map, map_length,
5532                                                      mirror_num);
5533                 }
5534         }
5535 
5536         if (map_length < length) {
5537                 btrfs_crit(root->fs_info, "mapping failed logical %llu bio len %llu len %llu",
5538                         logical, length, map_length);
5539                 BUG();
5540         }
5541 
5542         while (dev_nr < total_devs) {
5543                 dev = bbio->stripes[dev_nr].dev;
5544                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
5545                         bbio_error(bbio, first_bio, logical);
5546                         dev_nr++;
5547                         continue;
5548                 }
5549 
5550                 /*
5551                  * Check and see if we're ok with this bio based on it's size
5552                  * and offset with the given device.
5553                  */
5554                 if (!bio_size_ok(dev->bdev, first_bio,
5555                                  bbio->stripes[dev_nr].physical >> 9)) {
5556                         ret = breakup_stripe_bio(root, bbio, first_bio, dev,
5557                                                  dev_nr, rw, async_submit);
5558                         BUG_ON(ret);
5559                         dev_nr++;
5560                         continue;
5561                 }
5562 
5563                 if (dev_nr < total_devs - 1) {
5564                         bio = btrfs_bio_clone(first_bio, GFP_NOFS);
5565                         BUG_ON(!bio); /* -ENOMEM */
5566                 } else {
5567                         bio = first_bio;
5568                 }
5569 
5570                 submit_stripe_bio(root, bbio, bio,
5571                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
5572                                   async_submit);
5573                 dev_nr++;
5574         }
5575         return 0;
5576 }
5577 
5578 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
5579                                        u8 *uuid, u8 *fsid)
5580 {
5581         struct btrfs_device *device;
5582         struct btrfs_fs_devices *cur_devices;
5583 
5584         cur_devices = fs_info->fs_devices;
5585         while (cur_devices) {
5586                 if (!fsid ||
5587                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
5588                         device = __find_device(&cur_devices->devices,
5589                                                devid, uuid);
5590                         if (device)
5591                                 return device;
5592                 }
5593                 cur_devices = cur_devices->seed;
5594         }
5595         return NULL;
5596 }
5597 
5598 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
5599                                             u64 devid, u8 *dev_uuid)
5600 {
5601         struct btrfs_device *device;
5602         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
5603 
5604         device = btrfs_alloc_device(NULL, &devid, dev_uuid);
5605         if (IS_ERR(device))
5606                 return NULL;
5607 
5608         list_add(&device->dev_list, &fs_devices->devices);
5609         device->fs_devices = fs_devices;
5610         fs_devices->num_devices++;
5611 
5612         device->missing = 1;
5613         fs_devices->missing_devices++;
5614 
5615         return device;
5616 }
5617 
5618 /**
5619  * btrfs_alloc_device - allocate struct btrfs_device
5620  * @fs_info:    used only for generating a new devid, can be NULL if
5621  *              devid is provided (i.e. @devid != NULL).
5622  * @devid:      a pointer to devid for this device.  If NULL a new devid
5623  *              is generated.
5624  * @uuid:       a pointer to UUID for this device.  If NULL a new UUID
5625  *              is generated.
5626  *
5627  * Return: a pointer to a new &struct btrfs_device on success; ERR_PTR()
5628  * on error.  Returned struct is not linked onto any lists and can be
5629  * destroyed with kfree() right away.
5630  */
5631 struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
5632                                         const u64 *devid,
5633                                         const u8 *uuid)
5634 {
5635         struct btrfs_device *dev;
5636         u64 tmp;
5637 
5638         if (WARN_ON(!devid && !fs_info))
5639                 return ERR_PTR(-EINVAL);
5640 
5641         dev = __alloc_device();
5642         if (IS_ERR(dev))
5643                 return dev;
5644 
5645         if (devid)
5646                 tmp = *devid;
5647         else {
5648                 int ret;
5649 
5650                 ret = find_next_devid(fs_info, &tmp);
5651                 if (ret) {
5652                         kfree(dev);
5653                         return ERR_PTR(ret);
5654                 }
5655         }
5656         dev->devid = tmp;
5657 
5658         if (uuid)
5659                 memcpy(dev->uuid, uuid, BTRFS_UUID_SIZE);
5660         else
5661                 generate_random_uuid(dev->uuid);
5662 
5663         dev->work.func = pending_bios_fn;
5664 
5665         return dev;
5666 }
5667 
5668 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
5669                           struct extent_buffer *leaf,
5670                           struct btrfs_chunk *chunk)
5671 {
5672         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
5673         struct map_lookup *map;
5674         struct extent_map *em;
5675         u64 logical;
5676         u64 length;
5677         u64 devid;
5678         u8 uuid[BTRFS_UUID_SIZE];
5679         int num_stripes;
5680         int ret;
5681         int i;
5682 
5683         logical = key->offset;
5684         length = btrfs_chunk_length(leaf, chunk);
5685 
5686         read_lock(&map_tree->map_tree.lock);
5687         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
5688         read_unlock(&map_tree->map_tree.lock);
5689 
5690         /* already mapped? */
5691         if (em && em->start <= logical && em->start + em->len > logical) {
5692                 free_extent_map(em);
5693                 return 0;
5694         } else if (em) {
5695                 free_extent_map(em);
5696         }
5697 
5698         em = alloc_extent_map();
5699         if (!em)
5700                 return -ENOMEM;
5701         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
5702         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
5703         if (!map) {
5704                 free_extent_map(em);
5705                 return -ENOMEM;
5706         }
5707 
5708         em->bdev = (struct block_device *)map;
5709         em->start = logical;
5710         em->len = length;
5711         em->orig_start = 0;
5712         em->block_start = 0;
5713         em->block_len = em->len;
5714 
5715         map->num_stripes = num_stripes;
5716         map->io_width = btrfs_chunk_io_width(leaf, chunk);
5717         map->io_align = btrfs_chunk_io_align(leaf, chunk);
5718         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
5719         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
5720         map->type = btrfs_chunk_type(leaf, chunk);
5721         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
5722         for (i = 0; i < num_stripes; i++) {
5723                 map->stripes[i].physical =
5724                         btrfs_stripe_offset_nr(leaf, chunk, i);
5725                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
5726                 read_extent_buffer(leaf, uuid, (unsigned long)
5727                                    btrfs_stripe_dev_uuid_nr(chunk, i),
5728                                    BTRFS_UUID_SIZE);
5729                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
5730                                                         uuid, NULL);
5731                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
5732                         kfree(map);
5733                         free_extent_map(em);
5734                         return -EIO;
5735                 }
5736                 if (!map->stripes[i].dev) {
5737                         map->stripes[i].dev =
5738                                 add_missing_dev(root, devid, uuid);
5739                         if (!map->stripes[i].dev) {
5740                                 kfree(map);
5741                                 free_extent_map(em);
5742                                 return -EIO;
5743                         }
5744                 }
5745                 map->stripes[i].dev->in_fs_metadata = 1;
5746         }
5747 
5748         write_lock(&map_tree->map_tree.lock);
5749         ret = add_extent_mapping(&map_tree->map_tree, em, 0);
5750         write_unlock(&map_tree->map_tree.lock);
5751         BUG_ON(ret); /* Tree corruption */
5752         free_extent_map(em);
5753 
5754         return 0;
5755 }
5756 
5757 static void fill_device_from_item(struct extent_buffer *leaf,
5758                                  struct btrfs_dev_item *dev_item,
5759                                  struct btrfs_device *device)
5760 {
5761         unsigned long ptr;
5762 
5763         device->devid = btrfs_device_id(leaf, dev_item);
5764         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
5765         device->total_bytes = device->disk_total_bytes;
5766         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
5767         device->type = btrfs_device_type(leaf, dev_item);
5768         device->io_align = btrfs_device_io_align(leaf, dev_item);
5769         device->io_width = btrfs_device_io_width(leaf, dev_item);
5770         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
5771         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
5772         device->is_tgtdev_for_dev_replace = 0;
5773 
5774         ptr = btrfs_device_uuid(dev_item);
5775         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
5776 }
5777 
5778 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
5779 {
5780         struct btrfs_fs_devices *fs_devices;
5781         int ret;
5782 
5783         BUG_ON(!mutex_is_locked(&uuid_mutex));
5784 
5785         fs_devices = root->fs_info->fs_devices->seed;
5786         while (fs_devices) {
5787                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
5788                         ret = 0;
5789                         goto out;
5790                 }
5791                 fs_devices = fs_devices->seed;
5792         }
5793 
5794         fs_devices = find_fsid(fsid);
5795         if (!fs_devices) {
5796                 ret = -ENOENT;
5797                 goto out;
5798         }
5799 
5800         fs_devices = clone_fs_devices(fs_devices);
5801         if (IS_ERR(fs_devices)) {
5802                 ret = PTR_ERR(fs_devices);
5803                 goto out;
5804         }
5805 
5806         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
5807                                    root->fs_info->bdev_holder);
5808         if (ret) {
5809                 free_fs_devices(fs_devices);
5810                 goto out;
5811         }
5812 
5813         if (!fs_devices->seeding) {
5814                 __btrfs_close_devices(fs_devices);
5815                 free_fs_devices(fs_devices);
5816                 ret = -EINVAL;
5817                 goto out;
5818         }
5819 
5820         fs_devices->seed = root->fs_info->fs_devices->seed;
5821         root->fs_info->fs_devices->seed = fs_devices;
5822 out:
5823         return ret;
5824 }
5825 
5826 static int read_one_dev(struct btrfs_root *root,
5827                         struct extent_buffer *leaf,
5828                         struct btrfs_dev_item *dev_item)
5829 {
5830         struct btrfs_device *device;
5831         u64 devid;
5832         int ret;
5833         u8 fs_uuid[BTRFS_UUID_SIZE];
5834         u8 dev_uuid[BTRFS_UUID_SIZE];
5835 
5836         devid = btrfs_device_id(