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TOMOYO Linux Cross Reference
Linux/fs/nfs/pnfs.c

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  1 /*
  2  *  pNFS functions to call and manage layout drivers.
  3  *
  4  *  Copyright (c) 2002 [year of first publication]
  5  *  The Regents of the University of Michigan
  6  *  All Rights Reserved
  7  *
  8  *  Dean Hildebrand <dhildebz@umich.edu>
  9  *
 10  *  Permission is granted to use, copy, create derivative works, and
 11  *  redistribute this software and such derivative works for any purpose,
 12  *  so long as the name of the University of Michigan is not used in
 13  *  any advertising or publicity pertaining to the use or distribution
 14  *  of this software without specific, written prior authorization. If
 15  *  the above copyright notice or any other identification of the
 16  *  University of Michigan is included in any copy of any portion of
 17  *  this software, then the disclaimer below must also be included.
 18  *
 19  *  This software is provided as is, without representation or warranty
 20  *  of any kind either express or implied, including without limitation
 21  *  the implied warranties of merchantability, fitness for a particular
 22  *  purpose, or noninfringement.  The Regents of the University of
 23  *  Michigan shall not be liable for any damages, including special,
 24  *  indirect, incidental, or consequential damages, with respect to any
 25  *  claim arising out of or in connection with the use of the software,
 26  *  even if it has been or is hereafter advised of the possibility of
 27  *  such damages.
 28  */
 29 
 30 #include <linux/nfs_fs.h>
 31 #include <linux/nfs_page.h>
 32 #include <linux/module.h>
 33 #include "internal.h"
 34 #include "pnfs.h"
 35 #include "iostat.h"
 36 #include "nfs4trace.h"
 37 
 38 #define NFSDBG_FACILITY         NFSDBG_PNFS
 39 #define PNFS_LAYOUTGET_RETRY_TIMEOUT (120*HZ)
 40 
 41 /* Locking:
 42  *
 43  * pnfs_spinlock:
 44  *      protects pnfs_modules_tbl.
 45  */
 46 static DEFINE_SPINLOCK(pnfs_spinlock);
 47 
 48 /*
 49  * pnfs_modules_tbl holds all pnfs modules
 50  */
 51 static LIST_HEAD(pnfs_modules_tbl);
 52 
 53 /* Return the registered pnfs layout driver module matching given id */
 54 static struct pnfs_layoutdriver_type *
 55 find_pnfs_driver_locked(u32 id)
 56 {
 57         struct pnfs_layoutdriver_type *local;
 58 
 59         list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid)
 60                 if (local->id == id)
 61                         goto out;
 62         local = NULL;
 63 out:
 64         dprintk("%s: Searching for id %u, found %p\n", __func__, id, local);
 65         return local;
 66 }
 67 
 68 static struct pnfs_layoutdriver_type *
 69 find_pnfs_driver(u32 id)
 70 {
 71         struct pnfs_layoutdriver_type *local;
 72 
 73         spin_lock(&pnfs_spinlock);
 74         local = find_pnfs_driver_locked(id);
 75         if (local != NULL && !try_module_get(local->owner)) {
 76                 dprintk("%s: Could not grab reference on module\n", __func__);
 77                 local = NULL;
 78         }
 79         spin_unlock(&pnfs_spinlock);
 80         return local;
 81 }
 82 
 83 void
 84 unset_pnfs_layoutdriver(struct nfs_server *nfss)
 85 {
 86         if (nfss->pnfs_curr_ld) {
 87                 if (nfss->pnfs_curr_ld->clear_layoutdriver)
 88                         nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
 89                 /* Decrement the MDS count. Purge the deviceid cache if zero */
 90                 if (atomic_dec_and_test(&nfss->nfs_client->cl_mds_count))
 91                         nfs4_deviceid_purge_client(nfss->nfs_client);
 92                 module_put(nfss->pnfs_curr_ld->owner);
 93         }
 94         nfss->pnfs_curr_ld = NULL;
 95 }
 96 
 97 /*
 98  * Try to set the server's pnfs module to the pnfs layout type specified by id.
 99  * Currently only one pNFS layout driver per filesystem is supported.
100  *
101  * @id layout type. Zero (illegal layout type) indicates pNFS not in use.
102  */
103 void
104 set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
105                       u32 id)
106 {
107         struct pnfs_layoutdriver_type *ld_type = NULL;
108 
109         if (id == 0)
110                 goto out_no_driver;
111         if (!(server->nfs_client->cl_exchange_flags &
112                  (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) {
113                 printk(KERN_ERR "NFS: %s: id %u cl_exchange_flags 0x%x\n",
114                         __func__, id, server->nfs_client->cl_exchange_flags);
115                 goto out_no_driver;
116         }
117         ld_type = find_pnfs_driver(id);
118         if (!ld_type) {
119                 request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX, id);
120                 ld_type = find_pnfs_driver(id);
121                 if (!ld_type) {
122                         dprintk("%s: No pNFS module found for %u.\n",
123                                 __func__, id);
124                         goto out_no_driver;
125                 }
126         }
127         server->pnfs_curr_ld = ld_type;
128         if (ld_type->set_layoutdriver
129             && ld_type->set_layoutdriver(server, mntfh)) {
130                 printk(KERN_ERR "NFS: %s: Error initializing pNFS layout "
131                         "driver %u.\n", __func__, id);
132                 module_put(ld_type->owner);
133                 goto out_no_driver;
134         }
135         /* Bump the MDS count */
136         atomic_inc(&server->nfs_client->cl_mds_count);
137 
138         dprintk("%s: pNFS module for %u set\n", __func__, id);
139         return;
140 
141 out_no_driver:
142         dprintk("%s: Using NFSv4 I/O\n", __func__);
143         server->pnfs_curr_ld = NULL;
144 }
145 
146 int
147 pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
148 {
149         int status = -EINVAL;
150         struct pnfs_layoutdriver_type *tmp;
151 
152         if (ld_type->id == 0) {
153                 printk(KERN_ERR "NFS: %s id 0 is reserved\n", __func__);
154                 return status;
155         }
156         if (!ld_type->alloc_lseg || !ld_type->free_lseg) {
157                 printk(KERN_ERR "NFS: %s Layout driver must provide "
158                        "alloc_lseg and free_lseg.\n", __func__);
159                 return status;
160         }
161 
162         spin_lock(&pnfs_spinlock);
163         tmp = find_pnfs_driver_locked(ld_type->id);
164         if (!tmp) {
165                 list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl);
166                 status = 0;
167                 dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id,
168                         ld_type->name);
169         } else {
170                 printk(KERN_ERR "NFS: %s Module with id %d already loaded!\n",
171                         __func__, ld_type->id);
172         }
173         spin_unlock(&pnfs_spinlock);
174 
175         return status;
176 }
177 EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver);
178 
179 void
180 pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
181 {
182         dprintk("%s Deregistering id:%u\n", __func__, ld_type->id);
183         spin_lock(&pnfs_spinlock);
184         list_del(&ld_type->pnfs_tblid);
185         spin_unlock(&pnfs_spinlock);
186 }
187 EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);
188 
189 /*
190  * pNFS client layout cache
191  */
192 
193 /* Need to hold i_lock if caller does not already hold reference */
194 void
195 pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo)
196 {
197         atomic_inc(&lo->plh_refcount);
198 }
199 
200 static struct pnfs_layout_hdr *
201 pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
202 {
203         struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
204         return ld->alloc_layout_hdr(ino, gfp_flags);
205 }
206 
207 static void
208 pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
209 {
210         struct nfs_server *server = NFS_SERVER(lo->plh_inode);
211         struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
212 
213         if (!list_empty(&lo->plh_layouts)) {
214                 struct nfs_client *clp = server->nfs_client;
215 
216                 spin_lock(&clp->cl_lock);
217                 list_del_init(&lo->plh_layouts);
218                 spin_unlock(&clp->cl_lock);
219         }
220         put_rpccred(lo->plh_lc_cred);
221         return ld->free_layout_hdr(lo);
222 }
223 
224 static void
225 pnfs_detach_layout_hdr(struct pnfs_layout_hdr *lo)
226 {
227         struct nfs_inode *nfsi = NFS_I(lo->plh_inode);
228         dprintk("%s: freeing layout cache %p\n", __func__, lo);
229         nfsi->layout = NULL;
230         /* Reset MDS Threshold I/O counters */
231         nfsi->write_io = 0;
232         nfsi->read_io = 0;
233 }
234 
235 void
236 pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
237 {
238         struct inode *inode = lo->plh_inode;
239 
240         if (atomic_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
241                 pnfs_detach_layout_hdr(lo);
242                 spin_unlock(&inode->i_lock);
243                 pnfs_free_layout_hdr(lo);
244         }
245 }
246 
247 static int
248 pnfs_iomode_to_fail_bit(u32 iomode)
249 {
250         return iomode == IOMODE_RW ?
251                 NFS_LAYOUT_RW_FAILED : NFS_LAYOUT_RO_FAILED;
252 }
253 
254 static void
255 pnfs_layout_set_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
256 {
257         lo->plh_retry_timestamp = jiffies;
258         if (!test_and_set_bit(fail_bit, &lo->plh_flags))
259                 atomic_inc(&lo->plh_refcount);
260 }
261 
262 static void
263 pnfs_layout_clear_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
264 {
265         if (test_and_clear_bit(fail_bit, &lo->plh_flags))
266                 atomic_dec(&lo->plh_refcount);
267 }
268 
269 static void
270 pnfs_layout_io_set_failed(struct pnfs_layout_hdr *lo, u32 iomode)
271 {
272         struct inode *inode = lo->plh_inode;
273         struct pnfs_layout_range range = {
274                 .iomode = iomode,
275                 .offset = 0,
276                 .length = NFS4_MAX_UINT64,
277         };
278         LIST_HEAD(head);
279 
280         spin_lock(&inode->i_lock);
281         pnfs_layout_set_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
282         pnfs_mark_matching_lsegs_invalid(lo, &head, &range);
283         spin_unlock(&inode->i_lock);
284         pnfs_free_lseg_list(&head);
285         dprintk("%s Setting layout IOMODE_%s fail bit\n", __func__,
286                         iomode == IOMODE_RW ?  "RW" : "READ");
287 }
288 
289 static bool
290 pnfs_layout_io_test_failed(struct pnfs_layout_hdr *lo, u32 iomode)
291 {
292         unsigned long start, end;
293         int fail_bit = pnfs_iomode_to_fail_bit(iomode);
294 
295         if (test_bit(fail_bit, &lo->plh_flags) == 0)
296                 return false;
297         end = jiffies;
298         start = end - PNFS_LAYOUTGET_RETRY_TIMEOUT;
299         if (!time_in_range(lo->plh_retry_timestamp, start, end)) {
300                 /* It is time to retry the failed layoutgets */
301                 pnfs_layout_clear_fail_bit(lo, fail_bit);
302                 return false;
303         }
304         return true;
305 }
306 
307 static void
308 init_lseg(struct pnfs_layout_hdr *lo, struct pnfs_layout_segment *lseg)
309 {
310         INIT_LIST_HEAD(&lseg->pls_list);
311         INIT_LIST_HEAD(&lseg->pls_lc_list);
312         atomic_set(&lseg->pls_refcount, 1);
313         smp_mb();
314         set_bit(NFS_LSEG_VALID, &lseg->pls_flags);
315         lseg->pls_layout = lo;
316 }
317 
318 static void pnfs_free_lseg(struct pnfs_layout_segment *lseg)
319 {
320         struct inode *ino = lseg->pls_layout->plh_inode;
321 
322         NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
323 }
324 
325 static void
326 pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo,
327                 struct pnfs_layout_segment *lseg)
328 {
329         struct inode *inode = lo->plh_inode;
330 
331         WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
332         list_del_init(&lseg->pls_list);
333         /* Matched by pnfs_get_layout_hdr in pnfs_layout_insert_lseg */
334         atomic_dec(&lo->plh_refcount);
335         if (list_empty(&lo->plh_segs))
336                 clear_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
337         rpc_wake_up(&NFS_SERVER(inode)->roc_rpcwaitq);
338 }
339 
340 void
341 pnfs_put_lseg(struct pnfs_layout_segment *lseg)
342 {
343         struct pnfs_layout_hdr *lo;
344         struct inode *inode;
345 
346         if (!lseg)
347                 return;
348 
349         dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
350                 atomic_read(&lseg->pls_refcount),
351                 test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
352         lo = lseg->pls_layout;
353         inode = lo->plh_inode;
354         if (atomic_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
355                 pnfs_get_layout_hdr(lo);
356                 pnfs_layout_remove_lseg(lo, lseg);
357                 spin_unlock(&inode->i_lock);
358                 pnfs_free_lseg(lseg);
359                 pnfs_put_layout_hdr(lo);
360         }
361 }
362 EXPORT_SYMBOL_GPL(pnfs_put_lseg);
363 
364 static u64
365 end_offset(u64 start, u64 len)
366 {
367         u64 end;
368 
369         end = start + len;
370         return end >= start ? end : NFS4_MAX_UINT64;
371 }
372 
373 /*
374  * is l2 fully contained in l1?
375  *   start1                             end1
376  *   [----------------------------------)
377  *           start2           end2
378  *           [----------------)
379  */
380 static bool
381 pnfs_lseg_range_contained(const struct pnfs_layout_range *l1,
382                  const struct pnfs_layout_range *l2)
383 {
384         u64 start1 = l1->offset;
385         u64 end1 = end_offset(start1, l1->length);
386         u64 start2 = l2->offset;
387         u64 end2 = end_offset(start2, l2->length);
388 
389         return (start1 <= start2) && (end1 >= end2);
390 }
391 
392 /*
393  * is l1 and l2 intersecting?
394  *   start1                             end1
395  *   [----------------------------------)
396  *                              start2           end2
397  *                              [----------------)
398  */
399 static bool
400 pnfs_lseg_range_intersecting(const struct pnfs_layout_range *l1,
401                     const struct pnfs_layout_range *l2)
402 {
403         u64 start1 = l1->offset;
404         u64 end1 = end_offset(start1, l1->length);
405         u64 start2 = l2->offset;
406         u64 end2 = end_offset(start2, l2->length);
407 
408         return (end1 == NFS4_MAX_UINT64 || end1 > start2) &&
409                (end2 == NFS4_MAX_UINT64 || end2 > start1);
410 }
411 
412 static bool
413 should_free_lseg(const struct pnfs_layout_range *lseg_range,
414                  const struct pnfs_layout_range *recall_range)
415 {
416         return (recall_range->iomode == IOMODE_ANY ||
417                 lseg_range->iomode == recall_range->iomode) &&
418                pnfs_lseg_range_intersecting(lseg_range, recall_range);
419 }
420 
421 static bool pnfs_lseg_dec_and_remove_zero(struct pnfs_layout_segment *lseg,
422                 struct list_head *tmp_list)
423 {
424         if (!atomic_dec_and_test(&lseg->pls_refcount))
425                 return false;
426         pnfs_layout_remove_lseg(lseg->pls_layout, lseg);
427         list_add(&lseg->pls_list, tmp_list);
428         return true;
429 }
430 
431 /* Returns 1 if lseg is removed from list, 0 otherwise */
432 static int mark_lseg_invalid(struct pnfs_layout_segment *lseg,
433                              struct list_head *tmp_list)
434 {
435         int rv = 0;
436 
437         if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
438                 /* Remove the reference keeping the lseg in the
439                  * list.  It will now be removed when all
440                  * outstanding io is finished.
441                  */
442                 dprintk("%s: lseg %p ref %d\n", __func__, lseg,
443                         atomic_read(&lseg->pls_refcount));
444                 if (pnfs_lseg_dec_and_remove_zero(lseg, tmp_list))
445                         rv = 1;
446         }
447         return rv;
448 }
449 
450 /* Returns count of number of matching invalid lsegs remaining in list
451  * after call.
452  */
453 int
454 pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
455                             struct list_head *tmp_list,
456                             struct pnfs_layout_range *recall_range)
457 {
458         struct pnfs_layout_segment *lseg, *next;
459         int invalid = 0, removed = 0;
460 
461         dprintk("%s:Begin lo %p\n", __func__, lo);
462 
463         if (list_empty(&lo->plh_segs))
464                 return 0;
465         list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
466                 if (!recall_range ||
467                     should_free_lseg(&lseg->pls_range, recall_range)) {
468                         dprintk("%s: freeing lseg %p iomode %d "
469                                 "offset %llu length %llu\n", __func__,
470                                 lseg, lseg->pls_range.iomode, lseg->pls_range.offset,
471                                 lseg->pls_range.length);
472                         invalid++;
473                         removed += mark_lseg_invalid(lseg, tmp_list);
474                 }
475         dprintk("%s:Return %i\n", __func__, invalid - removed);
476         return invalid - removed;
477 }
478 
479 /* note free_me must contain lsegs from a single layout_hdr */
480 void
481 pnfs_free_lseg_list(struct list_head *free_me)
482 {
483         struct pnfs_layout_segment *lseg, *tmp;
484 
485         if (list_empty(free_me))
486                 return;
487 
488         list_for_each_entry_safe(lseg, tmp, free_me, pls_list) {
489                 list_del(&lseg->pls_list);
490                 pnfs_free_lseg(lseg);
491         }
492 }
493 
494 void
495 pnfs_destroy_layout(struct nfs_inode *nfsi)
496 {
497         struct pnfs_layout_hdr *lo;
498         LIST_HEAD(tmp_list);
499 
500         spin_lock(&nfsi->vfs_inode.i_lock);
501         lo = nfsi->layout;
502         if (lo) {
503                 lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
504                 pnfs_mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
505                 pnfs_get_layout_hdr(lo);
506                 pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RO_FAILED);
507                 pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RW_FAILED);
508                 spin_unlock(&nfsi->vfs_inode.i_lock);
509                 pnfs_free_lseg_list(&tmp_list);
510                 pnfs_put_layout_hdr(lo);
511         } else
512                 spin_unlock(&nfsi->vfs_inode.i_lock);
513 }
514 EXPORT_SYMBOL_GPL(pnfs_destroy_layout);
515 
516 static bool
517 pnfs_layout_add_bulk_destroy_list(struct inode *inode,
518                 struct list_head *layout_list)
519 {
520         struct pnfs_layout_hdr *lo;
521         bool ret = false;
522 
523         spin_lock(&inode->i_lock);
524         lo = NFS_I(inode)->layout;
525         if (lo != NULL && list_empty(&lo->plh_bulk_destroy)) {
526                 pnfs_get_layout_hdr(lo);
527                 list_add(&lo->plh_bulk_destroy, layout_list);
528                 ret = true;
529         }
530         spin_unlock(&inode->i_lock);
531         return ret;
532 }
533 
534 /* Caller must hold rcu_read_lock and clp->cl_lock */
535 static int
536 pnfs_layout_bulk_destroy_byserver_locked(struct nfs_client *clp,
537                 struct nfs_server *server,
538                 struct list_head *layout_list)
539 {
540         struct pnfs_layout_hdr *lo, *next;
541         struct inode *inode;
542 
543         list_for_each_entry_safe(lo, next, &server->layouts, plh_layouts) {
544                 inode = igrab(lo->plh_inode);
545                 if (inode == NULL)
546                         continue;
547                 list_del_init(&lo->plh_layouts);
548                 if (pnfs_layout_add_bulk_destroy_list(inode, layout_list))
549                         continue;
550                 rcu_read_unlock();
551                 spin_unlock(&clp->cl_lock);
552                 iput(inode);
553                 spin_lock(&clp->cl_lock);
554                 rcu_read_lock();
555                 return -EAGAIN;
556         }
557         return 0;
558 }
559 
560 static int
561 pnfs_layout_free_bulk_destroy_list(struct list_head *layout_list,
562                 bool is_bulk_recall)
563 {
564         struct pnfs_layout_hdr *lo;
565         struct inode *inode;
566         struct pnfs_layout_range range = {
567                 .iomode = IOMODE_ANY,
568                 .offset = 0,
569                 .length = NFS4_MAX_UINT64,
570         };
571         LIST_HEAD(lseg_list);
572         int ret = 0;
573 
574         while (!list_empty(layout_list)) {
575                 lo = list_entry(layout_list->next, struct pnfs_layout_hdr,
576                                 plh_bulk_destroy);
577                 dprintk("%s freeing layout for inode %lu\n", __func__,
578                         lo->plh_inode->i_ino);
579                 inode = lo->plh_inode;
580                 spin_lock(&inode->i_lock);
581                 list_del_init(&lo->plh_bulk_destroy);
582                 lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
583                 if (is_bulk_recall)
584                         set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
585                 if (pnfs_mark_matching_lsegs_invalid(lo, &lseg_list, &range))
586                         ret = -EAGAIN;
587                 spin_unlock(&inode->i_lock);
588                 pnfs_free_lseg_list(&lseg_list);
589                 pnfs_put_layout_hdr(lo);
590                 iput(inode);
591         }
592         return ret;
593 }
594 
595 int
596 pnfs_destroy_layouts_byfsid(struct nfs_client *clp,
597                 struct nfs_fsid *fsid,
598                 bool is_recall)
599 {
600         struct nfs_server *server;
601         LIST_HEAD(layout_list);
602 
603         spin_lock(&clp->cl_lock);
604         rcu_read_lock();
605 restart:
606         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
607                 if (memcmp(&server->fsid, fsid, sizeof(*fsid)) != 0)
608                         continue;
609                 if (pnfs_layout_bulk_destroy_byserver_locked(clp,
610                                 server,
611                                 &layout_list) != 0)
612                         goto restart;
613         }
614         rcu_read_unlock();
615         spin_unlock(&clp->cl_lock);
616 
617         if (list_empty(&layout_list))
618                 return 0;
619         return pnfs_layout_free_bulk_destroy_list(&layout_list, is_recall);
620 }
621 
622 int
623 pnfs_destroy_layouts_byclid(struct nfs_client *clp,
624                 bool is_recall)
625 {
626         struct nfs_server *server;
627         LIST_HEAD(layout_list);
628 
629         spin_lock(&clp->cl_lock);
630         rcu_read_lock();
631 restart:
632         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
633                 if (pnfs_layout_bulk_destroy_byserver_locked(clp,
634                                         server,
635                                         &layout_list) != 0)
636                         goto restart;
637         }
638         rcu_read_unlock();
639         spin_unlock(&clp->cl_lock);
640 
641         if (list_empty(&layout_list))
642                 return 0;
643         return pnfs_layout_free_bulk_destroy_list(&layout_list, is_recall);
644 }
645 
646 /*
647  * Called by the state manger to remove all layouts established under an
648  * expired lease.
649  */
650 void
651 pnfs_destroy_all_layouts(struct nfs_client *clp)
652 {
653         nfs4_deviceid_mark_client_invalid(clp);
654         nfs4_deviceid_purge_client(clp);
655 
656         pnfs_destroy_layouts_byclid(clp, false);
657 }
658 
659 /*
660  * Compare 2 layout stateid sequence ids, to see which is newer,
661  * taking into account wraparound issues.
662  */
663 static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
664 {
665         return (s32)s1 - (s32)s2 > 0;
666 }
667 
668 /* update lo->plh_stateid with new if is more recent */
669 void
670 pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
671                         bool update_barrier)
672 {
673         u32 oldseq, newseq, new_barrier;
674         int empty = list_empty(&lo->plh_segs);
675 
676         oldseq = be32_to_cpu(lo->plh_stateid.seqid);
677         newseq = be32_to_cpu(new->seqid);
678         if (empty || pnfs_seqid_is_newer(newseq, oldseq)) {
679                 nfs4_stateid_copy(&lo->plh_stateid, new);
680                 if (update_barrier) {
681                         new_barrier = be32_to_cpu(new->seqid);
682                 } else {
683                         /* Because of wraparound, we want to keep the barrier
684                          * "close" to the current seqids.
685                          */
686                         new_barrier = newseq - atomic_read(&lo->plh_outstanding);
687                 }
688                 if (empty || pnfs_seqid_is_newer(new_barrier, lo->plh_barrier))
689                         lo->plh_barrier = new_barrier;
690         }
691 }
692 
693 static bool
694 pnfs_layout_stateid_blocked(const struct pnfs_layout_hdr *lo,
695                 const nfs4_stateid *stateid)
696 {
697         u32 seqid = be32_to_cpu(stateid->seqid);
698 
699         return !pnfs_seqid_is_newer(seqid, lo->plh_barrier);
700 }
701 
702 /* lget is set to 1 if called from inside send_layoutget call chain */
703 static bool
704 pnfs_layoutgets_blocked(const struct pnfs_layout_hdr *lo, int lget)
705 {
706         return lo->plh_block_lgets ||
707                 test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) ||
708                 (list_empty(&lo->plh_segs) &&
709                  (atomic_read(&lo->plh_outstanding) > lget));
710 }
711 
712 int
713 pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
714                               struct nfs4_state *open_state)
715 {
716         int status = 0;
717 
718         dprintk("--> %s\n", __func__);
719         spin_lock(&lo->plh_inode->i_lock);
720         if (pnfs_layoutgets_blocked(lo, 1)) {
721                 status = -EAGAIN;
722         } else if (!nfs4_valid_open_stateid(open_state)) {
723                 status = -EBADF;
724         } else if (list_empty(&lo->plh_segs)) {
725                 int seq;
726 
727                 do {
728                         seq = read_seqbegin(&open_state->seqlock);
729                         nfs4_stateid_copy(dst, &open_state->stateid);
730                 } while (read_seqretry(&open_state->seqlock, seq));
731         } else
732                 nfs4_stateid_copy(dst, &lo->plh_stateid);
733         spin_unlock(&lo->plh_inode->i_lock);
734         dprintk("<-- %s\n", __func__);
735         return status;
736 }
737 
738 /*
739 * Get layout from server.
740 *    for now, assume that whole file layouts are requested.
741 *    arg->offset: 0
742 *    arg->length: all ones
743 */
744 static struct pnfs_layout_segment *
745 send_layoutget(struct pnfs_layout_hdr *lo,
746            struct nfs_open_context *ctx,
747            struct pnfs_layout_range *range,
748            gfp_t gfp_flags)
749 {
750         struct inode *ino = lo->plh_inode;
751         struct nfs_server *server = NFS_SERVER(ino);
752         struct nfs4_layoutget *lgp;
753         struct pnfs_layout_segment *lseg;
754 
755         dprintk("--> %s\n", __func__);
756 
757         lgp = kzalloc(sizeof(*lgp), gfp_flags);
758         if (lgp == NULL)
759                 return NULL;
760 
761         lgp->args.minlength = PAGE_CACHE_SIZE;
762         if (lgp->args.minlength > range->length)
763                 lgp->args.minlength = range->length;
764         lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
765         lgp->args.range = *range;
766         lgp->args.type = server->pnfs_curr_ld->id;
767         lgp->args.inode = ino;
768         lgp->args.ctx = get_nfs_open_context(ctx);
769         lgp->gfp_flags = gfp_flags;
770         lgp->cred = lo->plh_lc_cred;
771 
772         /* Synchronously retrieve layout information from server and
773          * store in lseg.
774          */
775         lseg = nfs4_proc_layoutget(lgp, gfp_flags);
776         if (IS_ERR(lseg)) {
777                 switch (PTR_ERR(lseg)) {
778                 case -ENOMEM:
779                 case -ERESTARTSYS:
780                         break;
781                 default:
782                         /* remember that LAYOUTGET failed and suspend trying */
783                         pnfs_layout_io_set_failed(lo, range->iomode);
784                 }
785                 return NULL;
786         }
787 
788         return lseg;
789 }
790 
791 static void pnfs_clear_layoutcommit(struct inode *inode,
792                 struct list_head *head)
793 {
794         struct nfs_inode *nfsi = NFS_I(inode);
795         struct pnfs_layout_segment *lseg, *tmp;
796 
797         if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
798                 return;
799         list_for_each_entry_safe(lseg, tmp, &nfsi->layout->plh_segs, pls_list) {
800                 if (!test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
801                         continue;
802                 pnfs_lseg_dec_and_remove_zero(lseg, head);
803         }
804 }
805 
806 /*
807  * Initiates a LAYOUTRETURN(FILE), and removes the pnfs_layout_hdr
808  * when the layout segment list is empty.
809  *
810  * Note that a pnfs_layout_hdr can exist with an empty layout segment
811  * list when LAYOUTGET has failed, or when LAYOUTGET succeeded, but the
812  * deviceid is marked invalid.
813  */
814 int
815 _pnfs_return_layout(struct inode *ino)
816 {
817         struct pnfs_layout_hdr *lo = NULL;
818         struct nfs_inode *nfsi = NFS_I(ino);
819         LIST_HEAD(tmp_list);
820         struct nfs4_layoutreturn *lrp;
821         nfs4_stateid stateid;
822         int status = 0, empty;
823 
824         dprintk("NFS: %s for inode %lu\n", __func__, ino->i_ino);
825 
826         spin_lock(&ino->i_lock);
827         lo = nfsi->layout;
828         if (!lo) {
829                 spin_unlock(&ino->i_lock);
830                 dprintk("NFS: %s no layout to return\n", __func__);
831                 goto out;
832         }
833         stateid = nfsi->layout->plh_stateid;
834         /* Reference matched in nfs4_layoutreturn_release */
835         pnfs_get_layout_hdr(lo);
836         empty = list_empty(&lo->plh_segs);
837         pnfs_clear_layoutcommit(ino, &tmp_list);
838         pnfs_mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
839         /* Don't send a LAYOUTRETURN if list was initially empty */
840         if (empty) {
841                 spin_unlock(&ino->i_lock);
842                 pnfs_put_layout_hdr(lo);
843                 dprintk("NFS: %s no layout segments to return\n", __func__);
844                 goto out;
845         }
846         lo->plh_block_lgets++;
847         spin_unlock(&ino->i_lock);
848         pnfs_free_lseg_list(&tmp_list);
849 
850         lrp = kzalloc(sizeof(*lrp), GFP_KERNEL);
851         if (unlikely(lrp == NULL)) {
852                 status = -ENOMEM;
853                 spin_lock(&ino->i_lock);
854                 lo->plh_block_lgets--;
855                 spin_unlock(&ino->i_lock);
856                 pnfs_put_layout_hdr(lo);
857                 goto out;
858         }
859 
860         lrp->args.stateid = stateid;
861         lrp->args.layout_type = NFS_SERVER(ino)->pnfs_curr_ld->id;
862         lrp->args.inode = ino;
863         lrp->args.layout = lo;
864         lrp->clp = NFS_SERVER(ino)->nfs_client;
865         lrp->cred = lo->plh_lc_cred;
866 
867         status = nfs4_proc_layoutreturn(lrp);
868 out:
869         dprintk("<-- %s status: %d\n", __func__, status);
870         return status;
871 }
872 EXPORT_SYMBOL_GPL(_pnfs_return_layout);
873 
874 int
875 pnfs_commit_and_return_layout(struct inode *inode)
876 {
877         struct pnfs_layout_hdr *lo;
878         int ret;
879 
880         spin_lock(&inode->i_lock);
881         lo = NFS_I(inode)->layout;
882         if (lo == NULL) {
883                 spin_unlock(&inode->i_lock);
884                 return 0;
885         }
886         pnfs_get_layout_hdr(lo);
887         /* Block new layoutgets and read/write to ds */
888         lo->plh_block_lgets++;
889         spin_unlock(&inode->i_lock);
890         filemap_fdatawait(inode->i_mapping);
891         ret = pnfs_layoutcommit_inode(inode, true);
892         if (ret == 0)
893                 ret = _pnfs_return_layout(inode);
894         spin_lock(&inode->i_lock);
895         lo->plh_block_lgets--;
896         spin_unlock(&inode->i_lock);
897         pnfs_put_layout_hdr(lo);
898         return ret;
899 }
900 
901 bool pnfs_roc(struct inode *ino)
902 {
903         struct pnfs_layout_hdr *lo;
904         struct pnfs_layout_segment *lseg, *tmp;
905         LIST_HEAD(tmp_list);
906         bool found = false;
907 
908         spin_lock(&ino->i_lock);
909         lo = NFS_I(ino)->layout;
910         if (!lo || !test_and_clear_bit(NFS_LAYOUT_ROC, &lo->plh_flags) ||
911             test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags))
912                 goto out_nolayout;
913         list_for_each_entry_safe(lseg, tmp, &lo->plh_segs, pls_list)
914                 if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
915                         mark_lseg_invalid(lseg, &tmp_list);
916                         found = true;
917                 }
918         if (!found)
919                 goto out_nolayout;
920         lo->plh_block_lgets++;
921         pnfs_get_layout_hdr(lo); /* matched in pnfs_roc_release */
922         spin_unlock(&ino->i_lock);
923         pnfs_free_lseg_list(&tmp_list);
924         return true;
925 
926 out_nolayout:
927         spin_unlock(&ino->i_lock);
928         return false;
929 }
930 
931 void pnfs_roc_release(struct inode *ino)
932 {
933         struct pnfs_layout_hdr *lo;
934 
935         spin_lock(&ino->i_lock);
936         lo = NFS_I(ino)->layout;
937         lo->plh_block_lgets--;
938         if (atomic_dec_and_test(&lo->plh_refcount)) {
939                 pnfs_detach_layout_hdr(lo);
940                 spin_unlock(&ino->i_lock);
941                 pnfs_free_layout_hdr(lo);
942         } else
943                 spin_unlock(&ino->i_lock);
944 }
945 
946 void pnfs_roc_set_barrier(struct inode *ino, u32 barrier)
947 {
948         struct pnfs_layout_hdr *lo;
949 
950         spin_lock(&ino->i_lock);
951         lo = NFS_I(ino)->layout;
952         if (pnfs_seqid_is_newer(barrier, lo->plh_barrier))
953                 lo->plh_barrier = barrier;
954         spin_unlock(&ino->i_lock);
955 }
956 
957 bool pnfs_roc_drain(struct inode *ino, u32 *barrier, struct rpc_task *task)
958 {
959         struct nfs_inode *nfsi = NFS_I(ino);
960         struct pnfs_layout_hdr *lo;
961         struct pnfs_layout_segment *lseg;
962         u32 current_seqid;
963         bool found = false;
964 
965         spin_lock(&ino->i_lock);
966         list_for_each_entry(lseg, &nfsi->layout->plh_segs, pls_list)
967                 if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
968                         rpc_sleep_on(&NFS_SERVER(ino)->roc_rpcwaitq, task, NULL);
969                         found = true;
970                         goto out;
971                 }
972         lo = nfsi->layout;
973         current_seqid = be32_to_cpu(lo->plh_stateid.seqid);
974 
975         /* Since close does not return a layout stateid for use as
976          * a barrier, we choose the worst-case barrier.
977          */
978         *barrier = current_seqid + atomic_read(&lo->plh_outstanding);
979 out:
980         spin_unlock(&ino->i_lock);
981         return found;
982 }
983 
984 /*
985  * Compare two layout segments for sorting into layout cache.
986  * We want to preferentially return RW over RO layouts, so ensure those
987  * are seen first.
988  */
989 static s64
990 pnfs_lseg_range_cmp(const struct pnfs_layout_range *l1,
991            const struct pnfs_layout_range *l2)
992 {
993         s64 d;
994 
995         /* high offset > low offset */
996         d = l1->offset - l2->offset;
997         if (d)
998                 return d;
999 
1000         /* short length > long length */
1001         d = l2->length - l1->length;
1002         if (d)
1003                 return d;
1004 
1005         /* read > read/write */
1006         return (int)(l1->iomode == IOMODE_READ) - (int)(l2->iomode == IOMODE_READ);
1007 }
1008 
1009 static void
1010 pnfs_layout_insert_lseg(struct pnfs_layout_hdr *lo,
1011                    struct pnfs_layout_segment *lseg)
1012 {
1013         struct pnfs_layout_segment *lp;
1014 
1015         dprintk("%s:Begin\n", __func__);
1016 
1017         list_for_each_entry(lp, &lo->plh_segs, pls_list) {
1018                 if (pnfs_lseg_range_cmp(&lseg->pls_range, &lp->pls_range) > 0)
1019                         continue;
1020                 list_add_tail(&lseg->pls_list, &lp->pls_list);
1021                 dprintk("%s: inserted lseg %p "
1022                         "iomode %d offset %llu length %llu before "
1023                         "lp %p iomode %d offset %llu length %llu\n",
1024                         __func__, lseg, lseg->pls_range.iomode,
1025                         lseg->pls_range.offset, lseg->pls_range.length,
1026                         lp, lp->pls_range.iomode, lp->pls_range.offset,
1027                         lp->pls_range.length);
1028                 goto out;
1029         }
1030         list_add_tail(&lseg->pls_list, &lo->plh_segs);
1031         dprintk("%s: inserted lseg %p "
1032                 "iomode %d offset %llu length %llu at tail\n",
1033                 __func__, lseg, lseg->pls_range.iomode,
1034                 lseg->pls_range.offset, lseg->pls_range.length);
1035 out:
1036         pnfs_get_layout_hdr(lo);
1037 
1038         dprintk("%s:Return\n", __func__);
1039 }
1040 
1041 static struct pnfs_layout_hdr *
1042 alloc_init_layout_hdr(struct inode *ino,
1043                       struct nfs_open_context *ctx,
1044                       gfp_t gfp_flags)
1045 {
1046         struct pnfs_layout_hdr *lo;
1047 
1048         lo = pnfs_alloc_layout_hdr(ino, gfp_flags);
1049         if (!lo)
1050                 return NULL;
1051         atomic_set(&lo->plh_refcount, 1);
1052         INIT_LIST_HEAD(&lo->plh_layouts);
1053         INIT_LIST_HEAD(&lo->plh_segs);
1054         INIT_LIST_HEAD(&lo->plh_bulk_destroy);
1055         lo->plh_inode = ino;
1056         lo->plh_lc_cred = get_rpccred(ctx->cred);
1057         return lo;
1058 }
1059 
1060 static struct pnfs_layout_hdr *
1061 pnfs_find_alloc_layout(struct inode *ino,
1062                        struct nfs_open_context *ctx,
1063                        gfp_t gfp_flags)
1064 {
1065         struct nfs_inode *nfsi = NFS_I(ino);
1066         struct pnfs_layout_hdr *new = NULL;
1067 
1068         dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);
1069 
1070         if (nfsi->layout != NULL)
1071                 goto out_existing;
1072         spin_unlock(&ino->i_lock);
1073         new = alloc_init_layout_hdr(ino, ctx, gfp_flags);
1074         spin_lock(&ino->i_lock);
1075 
1076         if (likely(nfsi->layout == NULL)) {     /* Won the race? */
1077                 nfsi->layout = new;
1078                 return new;
1079         } else if (new != NULL)
1080                 pnfs_free_layout_hdr(new);
1081 out_existing:
1082         pnfs_get_layout_hdr(nfsi->layout);
1083         return nfsi->layout;
1084 }
1085 
1086 /*
1087  * iomode matching rules:
1088  * iomode       lseg    match
1089  * -----        -----   -----
1090  * ANY          READ    true
1091  * ANY          RW      true
1092  * RW           READ    false
1093  * RW           RW      true
1094  * READ         READ    true
1095  * READ         RW      true
1096  */
1097 static bool
1098 pnfs_lseg_range_match(const struct pnfs_layout_range *ls_range,
1099                  const struct pnfs_layout_range *range)
1100 {
1101         struct pnfs_layout_range range1;
1102 
1103         if ((range->iomode == IOMODE_RW &&
1104              ls_range->iomode != IOMODE_RW) ||
1105             !pnfs_lseg_range_intersecting(ls_range, range))
1106                 return 0;
1107 
1108         /* range1 covers only the first byte in the range */
1109         range1 = *range;
1110         range1.length = 1;
1111         return pnfs_lseg_range_contained(ls_range, &range1);
1112 }
1113 
1114 /*
1115  * lookup range in layout
1116  */
1117 static struct pnfs_layout_segment *
1118 pnfs_find_lseg(struct pnfs_layout_hdr *lo,
1119                 struct pnfs_layout_range *range)
1120 {
1121         struct pnfs_layout_segment *lseg, *ret = NULL;
1122 
1123         dprintk("%s:Begin\n", __func__);
1124 
1125         list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
1126                 if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
1127                     pnfs_lseg_range_match(&lseg->pls_range, range)) {
1128                         ret = pnfs_get_lseg(lseg);
1129                         break;
1130                 }
1131                 if (lseg->pls_range.offset > range->offset)
1132                         break;
1133         }
1134 
1135         dprintk("%s:Return lseg %p ref %d\n",
1136                 __func__, ret, ret ? atomic_read(&ret->pls_refcount) : 0);
1137         return ret;
1138 }
1139 
1140 /*
1141  * Use mdsthreshold hints set at each OPEN to determine if I/O should go
1142  * to the MDS or over pNFS
1143  *
1144  * The nfs_inode read_io and write_io fields are cumulative counters reset
1145  * when there are no layout segments. Note that in pnfs_update_layout iomode
1146  * is set to IOMODE_READ for a READ request, and set to IOMODE_RW for a
1147  * WRITE request.
1148  *
1149  * A return of true means use MDS I/O.
1150  *
1151  * From rfc 5661:
1152  * If a file's size is smaller than the file size threshold, data accesses
1153  * SHOULD be sent to the metadata server.  If an I/O request has a length that
1154  * is below the I/O size threshold, the I/O SHOULD be sent to the metadata
1155  * server.  If both file size and I/O size are provided, the client SHOULD
1156  * reach or exceed  both thresholds before sending its read or write
1157  * requests to the data server.
1158  */
1159 static bool pnfs_within_mdsthreshold(struct nfs_open_context *ctx,
1160                                      struct inode *ino, int iomode)
1161 {
1162         struct nfs4_threshold *t = ctx->mdsthreshold;
1163         struct nfs_inode *nfsi = NFS_I(ino);
1164         loff_t fsize = i_size_read(ino);
1165         bool size = false, size_set = false, io = false, io_set = false, ret = false;
1166 
1167         if (t == NULL)
1168                 return ret;
1169 
1170         dprintk("%s bm=0x%x rd_sz=%llu wr_sz=%llu rd_io=%llu wr_io=%llu\n",
1171                 __func__, t->bm, t->rd_sz, t->wr_sz, t->rd_io_sz, t->wr_io_sz);
1172 
1173         switch (iomode) {
1174         case IOMODE_READ:
1175                 if (t->bm & THRESHOLD_RD) {
1176                         dprintk("%s fsize %llu\n", __func__, fsize);
1177                         size_set = true;
1178                         if (fsize < t->rd_sz)
1179                                 size = true;
1180                 }
1181                 if (t->bm & THRESHOLD_RD_IO) {
1182                         dprintk("%s nfsi->read_io %llu\n", __func__,
1183                                 nfsi->read_io);
1184                         io_set = true;
1185                         if (nfsi->read_io < t->rd_io_sz)
1186                                 io = true;
1187                 }
1188                 break;
1189         case IOMODE_RW:
1190                 if (t->bm & THRESHOLD_WR) {
1191                         dprintk("%s fsize %llu\n", __func__, fsize);
1192                         size_set = true;
1193                         if (fsize < t->wr_sz)
1194                                 size = true;
1195                 }
1196                 if (t->bm & THRESHOLD_WR_IO) {
1197                         dprintk("%s nfsi->write_io %llu\n", __func__,
1198                                 nfsi->write_io);
1199                         io_set = true;
1200                         if (nfsi->write_io < t->wr_io_sz)
1201                                 io = true;
1202                 }
1203                 break;
1204         }
1205         if (size_set && io_set) {
1206                 if (size && io)
1207                         ret = true;
1208         } else if (size || io)
1209                 ret = true;
1210 
1211         dprintk("<-- %s size %d io %d ret %d\n", __func__, size, io, ret);
1212         return ret;
1213 }
1214 
1215 /*
1216  * Layout segment is retreived from the server if not cached.
1217  * The appropriate layout segment is referenced and returned to the caller.
1218  */
1219 struct pnfs_layout_segment *
1220 pnfs_update_layout(struct inode *ino,
1221                    struct nfs_open_context *ctx,
1222                    loff_t pos,
1223                    u64 count,
1224                    enum pnfs_iomode iomode,
1225                    gfp_t gfp_flags)
1226 {
1227         struct pnfs_layout_range arg = {
1228                 .iomode = iomode,
1229                 .offset = pos,
1230                 .length = count,
1231         };
1232         unsigned pg_offset;
1233         struct nfs_server *server = NFS_SERVER(ino);
1234         struct nfs_client *clp = server->nfs_client;
1235         struct pnfs_layout_hdr *lo;
1236         struct pnfs_layout_segment *lseg = NULL;
1237         bool first;
1238 
1239         if (!pnfs_enabled_sb(NFS_SERVER(ino)))
1240                 goto out;
1241 
1242         if (pnfs_within_mdsthreshold(ctx, ino, iomode))
1243                 goto out;
1244 
1245         spin_lock(&ino->i_lock);
1246         lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
1247         if (lo == NULL) {
1248                 spin_unlock(&ino->i_lock);
1249                 goto out;
1250         }
1251 
1252         /* Do we even need to bother with this? */
1253         if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1254                 dprintk("%s matches recall, use MDS\n", __func__);
1255                 goto out_unlock;
1256         }
1257 
1258         /* if LAYOUTGET already failed once we don't try again */
1259         if (pnfs_layout_io_test_failed(lo, iomode))
1260                 goto out_unlock;
1261 
1262         /* Check to see if the layout for the given range already exists */
1263         lseg = pnfs_find_lseg(lo, &arg);
1264         if (lseg)
1265                 goto out_unlock;
1266 
1267         if (pnfs_layoutgets_blocked(lo, 0))
1268                 goto out_unlock;
1269         atomic_inc(&lo->plh_outstanding);
1270 
1271         first = list_empty(&lo->plh_layouts) ? true : false;
1272         spin_unlock(&ino->i_lock);
1273 
1274         if (first) {
1275                 /* The lo must be on the clp list if there is any
1276                  * chance of a CB_LAYOUTRECALL(FILE) coming in.
1277                  */
1278                 spin_lock(&clp->cl_lock);
1279                 list_add_tail(&lo->plh_layouts, &server->layouts);
1280                 spin_unlock(&clp->cl_lock);
1281         }
1282 
1283         pg_offset = arg.offset & ~PAGE_CACHE_MASK;
1284         if (pg_offset) {
1285                 arg.offset -= pg_offset;
1286                 arg.length += pg_offset;
1287         }
1288         if (arg.length != NFS4_MAX_UINT64)
1289                 arg.length = PAGE_CACHE_ALIGN(arg.length);
1290 
1291         lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
1292         atomic_dec(&lo->plh_outstanding);
1293 out_put_layout_hdr:
1294         pnfs_put_layout_hdr(lo);
1295 out:
1296         dprintk("%s: inode %s/%llu pNFS layout segment %s for "
1297                         "(%s, offset: %llu, length: %llu)\n",
1298                         __func__, ino->i_sb->s_id,
1299                         (unsigned long long)NFS_FILEID(ino),
1300                         lseg == NULL ? "not found" : "found",
1301                         iomode==IOMODE_RW ?  "read/write" : "read-only",
1302                         (unsigned long long)pos,
1303                         (unsigned long long)count);
1304         return lseg;
1305 out_unlock:
1306         spin_unlock(&ino->i_lock);
1307         goto out_put_layout_hdr;
1308 }
1309 EXPORT_SYMBOL_GPL(pnfs_update_layout);
1310 
1311 struct pnfs_layout_segment *
1312 pnfs_layout_process(struct nfs4_layoutget *lgp)
1313 {
1314         struct pnfs_layout_hdr *lo = NFS_I(lgp->args.inode)->layout;
1315         struct nfs4_layoutget_res *res = &lgp->res;
1316         struct pnfs_layout_segment *lseg;
1317         struct inode *ino = lo->plh_inode;
1318         int status = 0;
1319 
1320         /* Inject layout blob into I/O device driver */
1321         lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res, lgp->gfp_flags);
1322         if (!lseg || IS_ERR(lseg)) {
1323                 if (!lseg)
1324                         status = -ENOMEM;
1325                 else
1326                         status = PTR_ERR(lseg);
1327                 dprintk("%s: Could not allocate layout: error %d\n",
1328                        __func__, status);
1329                 goto out;
1330         }
1331 
1332         spin_lock(&ino->i_lock);
1333         if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1334                 dprintk("%s forget reply due to recall\n", __func__);
1335                 goto out_forget_reply;
1336         }
1337 
1338         if (pnfs_layoutgets_blocked(lo, 1) ||
1339             pnfs_layout_stateid_blocked(lo, &res->stateid)) {
1340                 dprintk("%s forget reply due to state\n", __func__);
1341                 goto out_forget_reply;
1342         }
1343 
1344         /* Done processing layoutget. Set the layout stateid */
1345         pnfs_set_layout_stateid(lo, &res->stateid, false);
1346 
1347         init_lseg(lo, lseg);
1348         lseg->pls_range = res->range;
1349         pnfs_get_lseg(lseg);
1350         pnfs_layout_insert_lseg(lo, lseg);
1351 
1352         if (res->return_on_close) {
1353                 set_bit(NFS_LSEG_ROC, &lseg->pls_flags);
1354                 set_bit(NFS_LAYOUT_ROC, &lo->plh_flags);
1355         }
1356 
1357         spin_unlock(&ino->i_lock);
1358         return lseg;
1359 out:
1360         return ERR_PTR(status);
1361 
1362 out_forget_reply:
1363         spin_unlock(&ino->i_lock);
1364         lseg->pls_layout = lo;
1365         NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
1366         goto out;
1367 }
1368 
1369 void
1370 pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
1371 {
1372         u64 rd_size = req->wb_bytes;
1373 
1374         WARN_ON_ONCE(pgio->pg_lseg != NULL);
1375 
1376         if (req->wb_offset != req->wb_pgbase) {
1377                 nfs_pageio_reset_read_mds(pgio);
1378                 return;
1379         }
1380 
1381         if (pgio->pg_dreq == NULL)
1382                 rd_size = i_size_read(pgio->pg_inode) - req_offset(req);
1383         else
1384                 rd_size = nfs_dreq_bytes_left(pgio->pg_dreq);
1385 
1386         pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
1387                                            req->wb_context,
1388                                            req_offset(req),
1389                                            rd_size,
1390                                            IOMODE_READ,
1391                                            GFP_KERNEL);
1392         /* If no lseg, fall back to read through mds */
1393         if (pgio->pg_lseg == NULL)
1394                 nfs_pageio_reset_read_mds(pgio);
1395 
1396 }
1397 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_read);
1398 
1399 void
1400 pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
1401                            struct nfs_page *req, u64 wb_size)
1402 {
1403         WARN_ON_ONCE(pgio->pg_lseg != NULL);
1404 
1405         if (req->wb_offset != req->wb_pgbase) {
1406                 nfs_pageio_reset_write_mds(pgio);
1407                 return;
1408         }
1409 
1410         pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
1411                                            req->wb_context,
1412                                            req_offset(req),
1413                                            wb_size,
1414                                            IOMODE_RW,
1415                                            GFP_NOFS);
1416         /* If no lseg, fall back to write through mds */
1417         if (pgio->pg_lseg == NULL)
1418                 nfs_pageio_reset_write_mds(pgio);
1419 }
1420 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
1421 
1422 void
1423 pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
1424                       const struct nfs_pgio_completion_ops *compl_ops)
1425 {
1426         struct nfs_server *server = NFS_SERVER(inode);
1427         struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
1428 
1429         if (ld == NULL)
1430                 nfs_pageio_init_read(pgio, inode, compl_ops);
1431         else
1432                 nfs_pageio_init(pgio, inode, ld->pg_read_ops, compl_ops, server->rsize, 0);
1433 }
1434 
1435 void
1436 pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode,
1437                        int ioflags,
1438                        const struct nfs_pgio_completion_ops *compl_ops)
1439 {
1440         struct nfs_server *server = NFS_SERVER(inode);
1441         struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
1442 
1443         if (ld == NULL)
1444                 nfs_pageio_init_write(pgio, inode, ioflags, compl_ops);
1445         else
1446                 nfs_pageio_init(pgio, inode, ld->pg_write_ops, compl_ops, server->wsize, ioflags);
1447 }
1448 
1449 bool
1450 pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
1451                      struct nfs_page *req)
1452 {
1453         if (pgio->pg_lseg == NULL)
1454                 return nfs_generic_pg_test(pgio, prev, req);
1455 
1456         /*
1457          * Test if a nfs_page is fully contained in the pnfs_layout_range.
1458          * Note that this test makes several assumptions:
1459          * - that the previous nfs_page in the struct nfs_pageio_descriptor
1460          *   is known to lie within the range.
1461          *   - that the nfs_page being tested is known to be contiguous with the
1462          *   previous nfs_page.
1463          *   - Layout ranges are page aligned, so we only have to test the
1464          *   start offset of the request.
1465          *
1466          * Please also note that 'end_offset' is actually the offset of the
1467          * first byte that lies outside the pnfs_layout_range. FIXME?
1468          *
1469          */
1470         return req_offset(req) < end_offset(pgio->pg_lseg->pls_range.offset,
1471                                          pgio->pg_lseg->pls_range.length);
1472 }
1473 EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);
1474 
1475 int pnfs_write_done_resend_to_mds(struct inode *inode,
1476                                 struct list_head *head,
1477                                 const struct nfs_pgio_completion_ops *compl_ops,
1478                                 struct nfs_direct_req *dreq)
1479 {
1480         struct nfs_pageio_descriptor pgio;
1481         LIST_HEAD(failed);
1482 
1483         /* Resend all requests through the MDS */
1484         nfs_pageio_init_write(&pgio, inode, FLUSH_STABLE, compl_ops);
1485         pgio.pg_dreq = dreq;
1486         while (!list_empty(head)) {
1487                 struct nfs_page *req = nfs_list_entry(head->next);
1488 
1489                 nfs_list_remove_request(req);
1490                 if (!nfs_pageio_add_request(&pgio, req))
1491                         nfs_list_add_request(req, &failed);
1492         }
1493         nfs_pageio_complete(&pgio);
1494 
1495         if (!list_empty(&failed)) {
1496                 /* For some reason our attempt to resend pages. Mark the
1497                  * overall send request as having failed, and let
1498                  * nfs_writeback_release_full deal with the error.
1499                  */
1500                 list_move(&failed, head);
1501                 return -EIO;
1502         }
1503         return 0;
1504 }
1505 EXPORT_SYMBOL_GPL(pnfs_write_done_resend_to_mds);
1506 
1507 static void pnfs_ld_handle_write_error(struct nfs_write_data *data)
1508 {
1509         struct nfs_pgio_header *hdr = data->header;
1510 
1511         dprintk("pnfs write error = %d\n", hdr->pnfs_error);
1512         if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
1513             PNFS_LAYOUTRET_ON_ERROR) {
1514                 pnfs_return_layout(hdr->inode);
1515         }
1516         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
1517                 data->task.tk_status = pnfs_write_done_resend_to_mds(hdr->inode,
1518                                                         &hdr->pages,
1519                                                         hdr->completion_ops,
1520                                                         hdr->dreq);
1521 }
1522 
1523 /*
1524  * Called by non rpc-based layout drivers
1525  */
1526 void pnfs_ld_write_done(struct nfs_write_data *data)
1527 {
1528         struct nfs_pgio_header *hdr = data->header;
1529 
1530         trace_nfs4_pnfs_write(data, hdr->pnfs_error);
1531         if (!hdr->pnfs_error) {
1532                 pnfs_set_layoutcommit(data);
1533                 hdr->mds_ops->rpc_call_done(&data->task, data);
1534         } else
1535                 pnfs_ld_handle_write_error(data);
1536         hdr->mds_ops->rpc_release(data);
1537 }
1538 EXPORT_SYMBOL_GPL(pnfs_ld_write_done);
1539 
1540 static void
1541 pnfs_write_through_mds(struct nfs_pageio_descriptor *desc,
1542                 struct nfs_write_data *data)
1543 {
1544         struct nfs_pgio_header *hdr = data->header;
1545 
1546         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1547                 list_splice_tail_init(&hdr->pages, &desc->pg_list);
1548                 nfs_pageio_reset_write_mds(desc);
1549                 desc->pg_recoalesce = 1;
1550         }
1551         nfs_writedata_release(data);
1552 }
1553 
1554 static enum pnfs_try_status
1555 pnfs_try_to_write_data(struct nfs_write_data *wdata,
1556                         const struct rpc_call_ops *call_ops,
1557                         struct pnfs_layout_segment *lseg,
1558                         int how)
1559 {
1560         struct nfs_pgio_header *hdr = wdata->header;
1561         struct inode *inode = hdr->inode;
1562         enum pnfs_try_status trypnfs;
1563         struct nfs_server *nfss = NFS_SERVER(inode);
1564 
1565         hdr->mds_ops = call_ops;
1566 
1567         dprintk("%s: Writing ino:%lu %u@%llu (how %d)\n", __func__,
1568                 inode->i_ino, wdata->args.count, wdata->args.offset, how);
1569         trypnfs = nfss->pnfs_curr_ld->write_pagelist(wdata, how);
1570         if (trypnfs != PNFS_NOT_ATTEMPTED)
1571                 nfs_inc_stats(inode, NFSIOS_PNFS_WRITE);
1572         dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
1573         return trypnfs;
1574 }
1575 
1576 static void
1577 pnfs_do_multiple_writes(struct nfs_pageio_descriptor *desc, struct list_head *head, int how)
1578 {
1579         struct nfs_write_data *data;
1580         const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
1581         struct pnfs_layout_segment *lseg = desc->pg_lseg;
1582 
1583         desc->pg_lseg = NULL;
1584         while (!list_empty(head)) {
1585                 enum pnfs_try_status trypnfs;
1586 
1587                 data = list_first_entry(head, struct nfs_write_data, list);
1588                 list_del_init(&data->list);
1589 
1590                 trypnfs = pnfs_try_to_write_data(data, call_ops, lseg, how);
1591                 if (trypnfs == PNFS_NOT_ATTEMPTED)
1592                         pnfs_write_through_mds(desc, data);
1593         }
1594         pnfs_put_lseg(lseg);
1595 }
1596 
1597 static void pnfs_writehdr_free(struct nfs_pgio_header *hdr)
1598 {
1599         pnfs_put_lseg(hdr->lseg);
1600         nfs_writehdr_free(hdr);
1601 }
1602 EXPORT_SYMBOL_GPL(pnfs_writehdr_free);
1603 
1604 int
1605 pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
1606 {
1607         struct nfs_write_header *whdr;
1608         struct nfs_pgio_header *hdr;
1609         int ret;
1610 
1611         whdr = nfs_writehdr_alloc();
1612         if (!whdr) {
1613                 desc->pg_completion_ops->error_cleanup(&desc->pg_list);
1614                 pnfs_put_lseg(desc->pg_lseg);
1615                 desc->pg_lseg = NULL;
1616                 return -ENOMEM;
1617         }
1618         hdr = &whdr->header;
1619         nfs_pgheader_init(desc, hdr, pnfs_writehdr_free);
1620         hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
1621         atomic_inc(&hdr->refcnt);
1622         ret = nfs_generic_flush(desc, hdr);
1623         if (ret != 0) {
1624                 pnfs_put_lseg(desc->pg_lseg);
1625                 desc->pg_lseg = NULL;
1626         } else
1627                 pnfs_do_multiple_writes(desc, &hdr->rpc_list, desc->pg_ioflags);
1628         if (atomic_dec_and_test(&hdr->refcnt))
1629                 hdr->completion_ops->completion(hdr);
1630         return ret;
1631 }
1632 EXPORT_SYMBOL_GPL(pnfs_generic_pg_writepages);
1633 
1634 int pnfs_read_done_resend_to_mds(struct inode *inode,
1635                                 struct list_head *head,
1636                                 const struct nfs_pgio_completion_ops *compl_ops,
1637                                 struct nfs_direct_req *dreq)
1638 {
1639         struct nfs_pageio_descriptor pgio;
1640         LIST_HEAD(failed);
1641 
1642         /* Resend all requests through the MDS */
1643         nfs_pageio_init_read(&pgio, inode, compl_ops);
1644         pgio.pg_dreq = dreq;
1645         while (!list_empty(head)) {
1646                 struct nfs_page *req = nfs_list_entry(head->next);
1647 
1648                 nfs_list_remove_request(req);
1649                 if (!nfs_pageio_add_request(&pgio, req))
1650                         nfs_list_add_request(req, &failed);
1651         }
1652         nfs_pageio_complete(&pgio);
1653 
1654         if (!list_empty(&failed)) {
1655                 list_move(&failed, head);
1656                 return -EIO;
1657         }
1658         return 0;
1659 }
1660 EXPORT_SYMBOL_GPL(pnfs_read_done_resend_to_mds);
1661 
1662 static void pnfs_ld_handle_read_error(struct nfs_read_data *data)
1663 {
1664         struct nfs_pgio_header *hdr = data->header;
1665 
1666         dprintk("pnfs read error = %d\n", hdr->pnfs_error);
1667         if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
1668             PNFS_LAYOUTRET_ON_ERROR) {
1669                 pnfs_return_layout(hdr->inode);
1670         }
1671         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
1672                 data->task.tk_status = pnfs_read_done_resend_to_mds(hdr->inode,
1673                                                         &hdr->pages,
1674                                                         hdr->completion_ops,
1675                                                         hdr->dreq);
1676 }
1677 
1678 /*
1679  * Called by non rpc-based layout drivers
1680  */
1681 void pnfs_ld_read_done(struct nfs_read_data *data)
1682 {
1683         struct nfs_pgio_header *hdr = data->header;
1684 
1685         trace_nfs4_pnfs_read(data, hdr->pnfs_error);
1686         if (likely(!hdr->pnfs_error)) {
1687                 __nfs4_read_done_cb(data);
1688                 hdr->mds_ops->rpc_call_done(&data->task, data);
1689         } else
1690                 pnfs_ld_handle_read_error(data);
1691         hdr->mds_ops->rpc_release(data);
1692 }
1693 EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
1694 
1695 static void
1696 pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
1697                 struct nfs_read_data *data)
1698 {
1699         struct nfs_pgio_header *hdr = data->header;
1700 
1701         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1702                 list_splice_tail_init(&hdr->pages, &desc->pg_list);
1703                 nfs_pageio_reset_read_mds(desc);
1704                 desc->pg_recoalesce = 1;
1705         }
1706         nfs_readdata_release(data);
1707 }
1708 
1709 /*
1710  * Call the appropriate parallel I/O subsystem read function.
1711  */
1712 static enum pnfs_try_status
1713 pnfs_try_to_read_data(struct nfs_read_data *rdata,
1714                        const struct rpc_call_ops *call_ops,
1715                        struct pnfs_layout_segment *lseg)
1716 {
1717         struct nfs_pgio_header *hdr = rdata->header;
1718         struct inode *inode = hdr->inode;
1719         struct nfs_server *nfss = NFS_SERVER(inode);
1720         enum pnfs_try_status trypnfs;
1721 
1722         hdr->mds_ops = call_ops;
1723 
1724         dprintk("%s: Reading ino:%lu %u@%llu\n",
1725                 __func__, inode->i_ino, rdata->args.count, rdata->args.offset);
1726 
1727         trypnfs = nfss->pnfs_curr_ld->read_pagelist(rdata);
1728         if (trypnfs != PNFS_NOT_ATTEMPTED)
1729                 nfs_inc_stats(inode, NFSIOS_PNFS_READ);
1730         dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
1731         return trypnfs;
1732 }
1733 
1734 static void
1735 pnfs_do_multiple_reads(struct nfs_pageio_descriptor *desc, struct list_head *head)
1736 {
1737         struct nfs_read_data *data;
1738         const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
1739         struct pnfs_layout_segment *lseg = desc->pg_lseg;
1740 
1741         desc->pg_lseg = NULL;
1742         while (!list_empty(head)) {
1743                 enum pnfs_try_status trypnfs;
1744 
1745                 data = list_first_entry(head, struct nfs_read_data, list);
1746                 list_del_init(&data->list);
1747 
1748                 trypnfs = pnfs_try_to_read_data(data, call_ops, lseg);
1749                 if (trypnfs == PNFS_NOT_ATTEMPTED)
1750                         pnfs_read_through_mds(desc, data);
1751         }
1752         pnfs_put_lseg(lseg);
1753 }
1754 
1755 static void pnfs_readhdr_free(struct nfs_pgio_header *hdr)
1756 {
1757         pnfs_put_lseg(hdr->lseg);
1758         nfs_readhdr_free(hdr);
1759 }
1760 EXPORT_SYMBOL_GPL(pnfs_readhdr_free);
1761 
1762 int
1763 pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
1764 {
1765         struct nfs_read_header *rhdr;
1766         struct nfs_pgio_header *hdr;
1767         int ret;
1768 
1769         rhdr = nfs_readhdr_alloc();
1770         if (!rhdr) {
1771                 desc->pg_completion_ops->error_cleanup(&desc->pg_list);
1772                 ret = -ENOMEM;
1773                 pnfs_put_lseg(desc->pg_lseg);
1774                 desc->pg_lseg = NULL;
1775                 return ret;
1776         }
1777         hdr = &rhdr->header;
1778         nfs_pgheader_init(desc, hdr, pnfs_readhdr_free);
1779         hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
1780         atomic_inc(&hdr->refcnt);
1781         ret = nfs_generic_pagein(desc, hdr);
1782         if (ret != 0) {
1783                 pnfs_put_lseg(desc->pg_lseg);
1784                 desc->pg_lseg = NULL;
1785         } else
1786                 pnfs_do_multiple_reads(desc, &hdr->rpc_list);
1787         if (atomic_dec_and_test(&hdr->refcnt))
1788                 hdr->completion_ops->completion(hdr);
1789         return ret;
1790 }
1791 EXPORT_SYMBOL_GPL(pnfs_generic_pg_readpages);
1792 
1793 static void pnfs_clear_layoutcommitting(struct inode *inode)
1794 {
1795         unsigned long *bitlock = &NFS_I(inode)->flags;
1796 
1797         clear_bit_unlock(NFS_INO_LAYOUTCOMMITTING, bitlock);
1798         smp_mb__after_clear_bit();
1799         wake_up_bit(bitlock, NFS_INO_LAYOUTCOMMITTING);
1800 }
1801 
1802 /*
1803  * There can be multiple RW segments.
1804  */
1805 static void pnfs_list_write_lseg(struct inode *inode, struct list_head *listp)
1806 {
1807         struct pnfs_layout_segment *lseg;
1808 
1809         list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) {
1810                 if (lseg->pls_range.iomode == IOMODE_RW &&
1811                     test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
1812                         list_add(&lseg->pls_lc_list, listp);
1813         }
1814 }
1815 
1816 static void pnfs_list_write_lseg_done(struct inode *inode, struct list_head *listp)
1817 {
1818         struct pnfs_layout_segment *lseg, *tmp;
1819 
1820         /* Matched by references in pnfs_set_layoutcommit */
1821         list_for_each_entry_safe(lseg, tmp, listp, pls_lc_list) {
1822                 list_del_init(&lseg->pls_lc_list);
1823                 pnfs_put_lseg(lseg);
1824         }
1825 
1826         pnfs_clear_layoutcommitting(inode);
1827 }
1828 
1829 void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg)
1830 {
1831         pnfs_layout_io_set_failed(lseg->pls_layout, lseg->pls_range.iomode);
1832 }
1833 EXPORT_SYMBOL_GPL(pnfs_set_lo_fail);
1834 
1835 void
1836 pnfs_set_layoutcommit(struct nfs_write_data *wdata)
1837 {
1838         struct nfs_pgio_header *hdr = wdata->header;
1839         struct inode *inode = hdr->inode;
1840         struct nfs_inode *nfsi = NFS_I(inode);
1841         loff_t end_pos = wdata->mds_offset + wdata->res.count;
1842         bool mark_as_dirty = false;
1843 
1844         spin_lock(&inode->i_lock);
1845         if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
1846                 mark_as_dirty = true;
1847                 dprintk("%s: Set layoutcommit for inode %lu ",
1848                         __func__, inode->i_ino);
1849         }
1850         if (!test_and_set_bit(NFS_LSEG_LAYOUTCOMMIT, &hdr->lseg->pls_flags)) {
1851                 /* references matched in nfs4_layoutcommit_release */
1852                 pnfs_get_lseg(hdr->lseg);
1853         }
1854         if (end_pos > nfsi->layout->plh_lwb)
1855                 nfsi->layout->plh_lwb = end_pos;
1856         spin_unlock(&inode->i_lock);
1857         dprintk("%s: lseg %p end_pos %llu\n",
1858                 __func__, hdr->lseg, nfsi->layout->plh_lwb);
1859 
1860         /* if pnfs_layoutcommit_inode() runs between inode locks, the next one
1861          * will be a noop because NFS_INO_LAYOUTCOMMIT will not be set */
1862         if (mark_as_dirty)
1863                 mark_inode_dirty_sync(inode);
1864 }
1865 EXPORT_SYMBOL_GPL(pnfs_set_layoutcommit);
1866 
1867 void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data)
1868 {
1869         struct nfs_server *nfss = NFS_SERVER(data->args.inode);
1870 
1871         if (nfss->pnfs_curr_ld->cleanup_layoutcommit)
1872                 nfss->pnfs_curr_ld->cleanup_layoutcommit(data);
1873         pnfs_list_write_lseg_done(data->args.inode, &data->lseg_list);
1874 }
1875 
1876 /*
1877  * For the LAYOUT4_NFSV4_1_FILES layout type, NFS_DATA_SYNC WRITEs and
1878  * NFS_UNSTABLE WRITEs with a COMMIT to data servers must store enough
1879  * data to disk to allow the server to recover the data if it crashes.
1880  * LAYOUTCOMMIT is only needed when the NFL4_UFLG_COMMIT_THRU_MDS flag
1881  * is off, and a COMMIT is sent to a data server, or
1882  * if WRITEs to a data server return NFS_DATA_SYNC.
1883  */
1884 int
1885 pnfs_layoutcommit_inode(struct inode *inode, bool sync)
1886 {
1887         struct nfs4_layoutcommit_data *data;
1888         struct nfs_inode *nfsi = NFS_I(inode);
1889         loff_t end_pos;
1890         int status;
1891 
1892         if (!pnfs_layoutcommit_outstanding(inode))
1893                 return 0;
1894 
1895         dprintk("--> %s inode %lu\n", __func__, inode->i_ino);
1896 
1897         status = -EAGAIN;
1898         if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
1899                 if (!sync)
1900                         goto out;
1901                 status = wait_on_bit_lock(&nfsi->flags,
1902                                 NFS_INO_LAYOUTCOMMITTING,
1903                                 nfs_wait_bit_killable,
1904                                 TASK_KILLABLE);
1905                 if (status)
1906                         goto out;
1907         }
1908 
1909         status = -ENOMEM;
1910         /* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
1911         data = kzalloc(sizeof(*data), GFP_NOFS);
1912         if (!data)
1913                 goto clear_layoutcommitting;
1914 
1915         status = 0;
1916         spin_lock(&inode->i_lock);
1917         if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
1918                 goto out_unlock;
1919 
1920         INIT_LIST_HEAD(&data->lseg_list);
1921         pnfs_list_write_lseg(inode, &data->lseg_list);
1922 
1923         end_pos = nfsi->layout->plh_lwb;
1924         nfsi->layout->plh_lwb = 0;
1925 
1926         nfs4_stateid_copy(&data->args.stateid, &nfsi->layout->plh_stateid);
1927         spin_unlock(&inode->i_lock);
1928 
1929         data->args.inode = inode;
1930         data->cred = get_rpccred(nfsi->layout->plh_lc_cred);
1931         nfs_fattr_init(&data->fattr);
1932         data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
1933         data->res.fattr = &data->fattr;
1934         data->args.lastbytewritten = end_pos - 1;
1935         data->res.server = NFS_SERVER(inode);
1936 
1937         status = nfs4_proc_layoutcommit(data, sync);
1938 out:
1939         if (status)
1940                 mark_inode_dirty_sync(inode);
1941         dprintk("<-- %s status %d\n", __func__, status);
1942         return status;
1943 out_unlock:
1944         spin_unlock(&inode->i_lock);
1945         kfree(data);
1946 clear_layoutcommitting:
1947         pnfs_clear_layoutcommitting(inode);
1948         goto out;
1949 }
1950 
1951 struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
1952 {
1953         struct nfs4_threshold *thp;
1954 
1955         thp = kzalloc(sizeof(*thp), GFP_NOFS);
1956         if (!thp) {
1957                 dprintk("%s mdsthreshold allocation failed\n", __func__);
1958                 return NULL;
1959         }
1960         return thp;
1961 }
1962 

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