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TOMOYO Linux Cross Reference
Linux/fs/btrfs/check-integrity.c

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  1 /*
  2  * Copyright (C) STRATO AG 2011.  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 
 19 /*
 20  * This module can be used to catch cases when the btrfs kernel
 21  * code executes write requests to the disk that bring the file
 22  * system in an inconsistent state. In such a state, a power-loss
 23  * or kernel panic event would cause that the data on disk is
 24  * lost or at least damaged.
 25  *
 26  * Code is added that examines all block write requests during
 27  * runtime (including writes of the super block). Three rules
 28  * are verified and an error is printed on violation of the
 29  * rules:
 30  * 1. It is not allowed to write a disk block which is
 31  *    currently referenced by the super block (either directly
 32  *    or indirectly).
 33  * 2. When a super block is written, it is verified that all
 34  *    referenced (directly or indirectly) blocks fulfill the
 35  *    following requirements:
 36  *    2a. All referenced blocks have either been present when
 37  *        the file system was mounted, (i.e., they have been
 38  *        referenced by the super block) or they have been
 39  *        written since then and the write completion callback
 40  *        was called and no write error was indicated and a
 41  *        FLUSH request to the device where these blocks are
 42  *        located was received and completed.
 43  *    2b. All referenced blocks need to have a generation
 44  *        number which is equal to the parent's number.
 45  *
 46  * One issue that was found using this module was that the log
 47  * tree on disk became temporarily corrupted because disk blocks
 48  * that had been in use for the log tree had been freed and
 49  * reused too early, while being referenced by the written super
 50  * block.
 51  *
 52  * The search term in the kernel log that can be used to filter
 53  * on the existence of detected integrity issues is
 54  * "btrfs: attempt".
 55  *
 56  * The integrity check is enabled via mount options. These
 57  * mount options are only supported if the integrity check
 58  * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
 59  *
 60  * Example #1, apply integrity checks to all metadata:
 61  * mount /dev/sdb1 /mnt -o check_int
 62  *
 63  * Example #2, apply integrity checks to all metadata and
 64  * to data extents:
 65  * mount /dev/sdb1 /mnt -o check_int_data
 66  *
 67  * Example #3, apply integrity checks to all metadata and dump
 68  * the tree that the super block references to kernel messages
 69  * each time after a super block was written:
 70  * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
 71  *
 72  * If the integrity check tool is included and activated in
 73  * the mount options, plenty of kernel memory is used, and
 74  * plenty of additional CPU cycles are spent. Enabling this
 75  * functionality is not intended for normal use. In most
 76  * cases, unless you are a btrfs developer who needs to verify
 77  * the integrity of (super)-block write requests, do not
 78  * enable the config option BTRFS_FS_CHECK_INTEGRITY to
 79  * include and compile the integrity check tool.
 80  *
 81  * Expect millions of lines of information in the kernel log with an
 82  * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
 83  * kernel config to at least 26 (which is 64MB). Usually the value is
 84  * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
 85  * changed like this before LOG_BUF_SHIFT can be set to a high value:
 86  * config LOG_BUF_SHIFT
 87  *       int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
 88  *       range 12 30
 89  */
 90 
 91 #include <linux/sched.h>
 92 #include <linux/slab.h>
 93 #include <linux/buffer_head.h>
 94 #include <linux/mutex.h>
 95 #include <linux/genhd.h>
 96 #include <linux/blkdev.h>
 97 #include <linux/vmalloc.h>
 98 #include <linux/string.h>
 99 #include "ctree.h"
100 #include "disk-io.h"
101 #include "hash.h"
102 #include "transaction.h"
103 #include "extent_io.h"
104 #include "volumes.h"
105 #include "print-tree.h"
106 #include "locking.h"
107 #include "check-integrity.h"
108 #include "rcu-string.h"
109 #include "compression.h"
110 
111 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
112 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
113 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
114 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
115 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
116 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
117 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
118 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)    /* in characters,
119                                                          * excluding " [...]" */
120 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
121 
122 /*
123  * The definition of the bitmask fields for the print_mask.
124  * They are specified with the mount option check_integrity_print_mask.
125  */
126 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE                     0x00000001
127 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION         0x00000002
128 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE                  0x00000004
129 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE                 0x00000008
130 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH                        0x00000010
131 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH                        0x00000020
132 #define BTRFSIC_PRINT_MASK_VERBOSE                              0x00000040
133 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE                         0x00000080
134 #define BTRFSIC_PRINT_MASK_INITIAL_TREE                         0x00000100
135 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES                    0x00000200
136 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE                     0x00000400
137 #define BTRFSIC_PRINT_MASK_NUM_COPIES                           0x00000800
138 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS                0x00001000
139 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE                0x00002000
140 
141 struct btrfsic_dev_state;
142 struct btrfsic_state;
143 
144 struct btrfsic_block {
145         u32 magic_num;          /* only used for debug purposes */
146         unsigned int is_metadata:1;     /* if it is meta-data, not data-data */
147         unsigned int is_superblock:1;   /* if it is one of the superblocks */
148         unsigned int is_iodone:1;       /* if is done by lower subsystem */
149         unsigned int iodone_w_error:1;  /* error was indicated to endio */
150         unsigned int never_written:1;   /* block was added because it was
151                                          * referenced, not because it was
152                                          * written */
153         unsigned int mirror_num;        /* large enough to hold
154                                          * BTRFS_SUPER_MIRROR_MAX */
155         struct btrfsic_dev_state *dev_state;
156         u64 dev_bytenr;         /* key, physical byte num on disk */
157         u64 logical_bytenr;     /* logical byte num on disk */
158         u64 generation;
159         struct btrfs_disk_key disk_key; /* extra info to print in case of
160                                          * issues, will not always be correct */
161         struct list_head collision_resolving_node;      /* list node */
162         struct list_head all_blocks_node;       /* list node */
163 
164         /* the following two lists contain block_link items */
165         struct list_head ref_to_list;   /* list */
166         struct list_head ref_from_list; /* list */
167         struct btrfsic_block *next_in_same_bio;
168         void *orig_bio_bh_private;
169         union {
170                 bio_end_io_t *bio;
171                 bh_end_io_t *bh;
172         } orig_bio_bh_end_io;
173         int submit_bio_bh_rw;
174         u64 flush_gen; /* only valid if !never_written */
175 };
176 
177 /*
178  * Elements of this type are allocated dynamically and required because
179  * each block object can refer to and can be ref from multiple blocks.
180  * The key to lookup them in the hashtable is the dev_bytenr of
181  * the block ref to plus the one from the block referred from.
182  * The fact that they are searchable via a hashtable and that a
183  * ref_cnt is maintained is not required for the btrfs integrity
184  * check algorithm itself, it is only used to make the output more
185  * beautiful in case that an error is detected (an error is defined
186  * as a write operation to a block while that block is still referenced).
187  */
188 struct btrfsic_block_link {
189         u32 magic_num;          /* only used for debug purposes */
190         u32 ref_cnt;
191         struct list_head node_ref_to;   /* list node */
192         struct list_head node_ref_from; /* list node */
193         struct list_head collision_resolving_node;      /* list node */
194         struct btrfsic_block *block_ref_to;
195         struct btrfsic_block *block_ref_from;
196         u64 parent_generation;
197 };
198 
199 struct btrfsic_dev_state {
200         u32 magic_num;          /* only used for debug purposes */
201         struct block_device *bdev;
202         struct btrfsic_state *state;
203         struct list_head collision_resolving_node;      /* list node */
204         struct btrfsic_block dummy_block_for_bio_bh_flush;
205         u64 last_flush_gen;
206         char name[BDEVNAME_SIZE];
207 };
208 
209 struct btrfsic_block_hashtable {
210         struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
211 };
212 
213 struct btrfsic_block_link_hashtable {
214         struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
215 };
216 
217 struct btrfsic_dev_state_hashtable {
218         struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
219 };
220 
221 struct btrfsic_block_data_ctx {
222         u64 start;              /* virtual bytenr */
223         u64 dev_bytenr;         /* physical bytenr on device */
224         u32 len;
225         struct btrfsic_dev_state *dev;
226         char **datav;
227         struct page **pagev;
228         void *mem_to_free;
229 };
230 
231 /* This structure is used to implement recursion without occupying
232  * any stack space, refer to btrfsic_process_metablock() */
233 struct btrfsic_stack_frame {
234         u32 magic;
235         u32 nr;
236         int error;
237         int i;
238         int limit_nesting;
239         int num_copies;
240         int mirror_num;
241         struct btrfsic_block *block;
242         struct btrfsic_block_data_ctx *block_ctx;
243         struct btrfsic_block *next_block;
244         struct btrfsic_block_data_ctx next_block_ctx;
245         struct btrfs_header *hdr;
246         struct btrfsic_stack_frame *prev;
247 };
248 
249 /* Some state per mounted filesystem */
250 struct btrfsic_state {
251         u32 print_mask;
252         int include_extent_data;
253         int csum_size;
254         struct list_head all_blocks_list;
255         struct btrfsic_block_hashtable block_hashtable;
256         struct btrfsic_block_link_hashtable block_link_hashtable;
257         struct btrfs_root *root;
258         u64 max_superblock_generation;
259         struct btrfsic_block *latest_superblock;
260         u32 metablock_size;
261         u32 datablock_size;
262 };
263 
264 static void btrfsic_block_init(struct btrfsic_block *b);
265 static struct btrfsic_block *btrfsic_block_alloc(void);
266 static void btrfsic_block_free(struct btrfsic_block *b);
267 static void btrfsic_block_link_init(struct btrfsic_block_link *n);
268 static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
269 static void btrfsic_block_link_free(struct btrfsic_block_link *n);
270 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
271 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
272 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
273 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
274 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
275                                         struct btrfsic_block_hashtable *h);
276 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
277 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
278                 struct block_device *bdev,
279                 u64 dev_bytenr,
280                 struct btrfsic_block_hashtable *h);
281 static void btrfsic_block_link_hashtable_init(
282                 struct btrfsic_block_link_hashtable *h);
283 static void btrfsic_block_link_hashtable_add(
284                 struct btrfsic_block_link *l,
285                 struct btrfsic_block_link_hashtable *h);
286 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
287 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
288                 struct block_device *bdev_ref_to,
289                 u64 dev_bytenr_ref_to,
290                 struct block_device *bdev_ref_from,
291                 u64 dev_bytenr_ref_from,
292                 struct btrfsic_block_link_hashtable *h);
293 static void btrfsic_dev_state_hashtable_init(
294                 struct btrfsic_dev_state_hashtable *h);
295 static void btrfsic_dev_state_hashtable_add(
296                 struct btrfsic_dev_state *ds,
297                 struct btrfsic_dev_state_hashtable *h);
298 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
299 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
300                 struct block_device *bdev,
301                 struct btrfsic_dev_state_hashtable *h);
302 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
303 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
304 static int btrfsic_process_superblock(struct btrfsic_state *state,
305                                       struct btrfs_fs_devices *fs_devices);
306 static int btrfsic_process_metablock(struct btrfsic_state *state,
307                                      struct btrfsic_block *block,
308                                      struct btrfsic_block_data_ctx *block_ctx,
309                                      int limit_nesting, int force_iodone_flag);
310 static void btrfsic_read_from_block_data(
311         struct btrfsic_block_data_ctx *block_ctx,
312         void *dst, u32 offset, size_t len);
313 static int btrfsic_create_link_to_next_block(
314                 struct btrfsic_state *state,
315                 struct btrfsic_block *block,
316                 struct btrfsic_block_data_ctx
317                 *block_ctx, u64 next_bytenr,
318                 int limit_nesting,
319                 struct btrfsic_block_data_ctx *next_block_ctx,
320                 struct btrfsic_block **next_blockp,
321                 int force_iodone_flag,
322                 int *num_copiesp, int *mirror_nump,
323                 struct btrfs_disk_key *disk_key,
324                 u64 parent_generation);
325 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
326                                       struct btrfsic_block *block,
327                                       struct btrfsic_block_data_ctx *block_ctx,
328                                       u32 item_offset, int force_iodone_flag);
329 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
330                              struct btrfsic_block_data_ctx *block_ctx_out,
331                              int mirror_num);
332 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
333 static int btrfsic_read_block(struct btrfsic_state *state,
334                               struct btrfsic_block_data_ctx *block_ctx);
335 static void btrfsic_dump_database(struct btrfsic_state *state);
336 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
337                                      char **datav, unsigned int num_pages);
338 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
339                                           u64 dev_bytenr, char **mapped_datav,
340                                           unsigned int num_pages,
341                                           struct bio *bio, int *bio_is_patched,
342                                           struct buffer_head *bh,
343                                           int submit_bio_bh_rw);
344 static int btrfsic_process_written_superblock(
345                 struct btrfsic_state *state,
346                 struct btrfsic_block *const block,
347                 struct btrfs_super_block *const super_hdr);
348 static void btrfsic_bio_end_io(struct bio *bp);
349 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
350 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
351                                               const struct btrfsic_block *block,
352                                               int recursion_level);
353 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
354                                         struct btrfsic_block *const block,
355                                         int recursion_level);
356 static void btrfsic_print_add_link(const struct btrfsic_state *state,
357                                    const struct btrfsic_block_link *l);
358 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
359                                    const struct btrfsic_block_link *l);
360 static char btrfsic_get_block_type(const struct btrfsic_state *state,
361                                    const struct btrfsic_block *block);
362 static void btrfsic_dump_tree(const struct btrfsic_state *state);
363 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
364                                   const struct btrfsic_block *block,
365                                   int indent_level);
366 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
367                 struct btrfsic_state *state,
368                 struct btrfsic_block_data_ctx *next_block_ctx,
369                 struct btrfsic_block *next_block,
370                 struct btrfsic_block *from_block,
371                 u64 parent_generation);
372 static struct btrfsic_block *btrfsic_block_lookup_or_add(
373                 struct btrfsic_state *state,
374                 struct btrfsic_block_data_ctx *block_ctx,
375                 const char *additional_string,
376                 int is_metadata,
377                 int is_iodone,
378                 int never_written,
379                 int mirror_num,
380                 int *was_created);
381 static int btrfsic_process_superblock_dev_mirror(
382                 struct btrfsic_state *state,
383                 struct btrfsic_dev_state *dev_state,
384                 struct btrfs_device *device,
385                 int superblock_mirror_num,
386                 struct btrfsic_dev_state **selected_dev_state,
387                 struct btrfs_super_block *selected_super);
388 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
389                 struct block_device *bdev);
390 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
391                                            u64 bytenr,
392                                            struct btrfsic_dev_state *dev_state,
393                                            u64 dev_bytenr);
394 
395 static struct mutex btrfsic_mutex;
396 static int btrfsic_is_initialized;
397 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
398 
399 
400 static void btrfsic_block_init(struct btrfsic_block *b)
401 {
402         b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
403         b->dev_state = NULL;
404         b->dev_bytenr = 0;
405         b->logical_bytenr = 0;
406         b->generation = BTRFSIC_GENERATION_UNKNOWN;
407         b->disk_key.objectid = 0;
408         b->disk_key.type = 0;
409         b->disk_key.offset = 0;
410         b->is_metadata = 0;
411         b->is_superblock = 0;
412         b->is_iodone = 0;
413         b->iodone_w_error = 0;
414         b->never_written = 0;
415         b->mirror_num = 0;
416         b->next_in_same_bio = NULL;
417         b->orig_bio_bh_private = NULL;
418         b->orig_bio_bh_end_io.bio = NULL;
419         INIT_LIST_HEAD(&b->collision_resolving_node);
420         INIT_LIST_HEAD(&b->all_blocks_node);
421         INIT_LIST_HEAD(&b->ref_to_list);
422         INIT_LIST_HEAD(&b->ref_from_list);
423         b->submit_bio_bh_rw = 0;
424         b->flush_gen = 0;
425 }
426 
427 static struct btrfsic_block *btrfsic_block_alloc(void)
428 {
429         struct btrfsic_block *b;
430 
431         b = kzalloc(sizeof(*b), GFP_NOFS);
432         if (NULL != b)
433                 btrfsic_block_init(b);
434 
435         return b;
436 }
437 
438 static void btrfsic_block_free(struct btrfsic_block *b)
439 {
440         BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
441         kfree(b);
442 }
443 
444 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
445 {
446         l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
447         l->ref_cnt = 1;
448         INIT_LIST_HEAD(&l->node_ref_to);
449         INIT_LIST_HEAD(&l->node_ref_from);
450         INIT_LIST_HEAD(&l->collision_resolving_node);
451         l->block_ref_to = NULL;
452         l->block_ref_from = NULL;
453 }
454 
455 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
456 {
457         struct btrfsic_block_link *l;
458 
459         l = kzalloc(sizeof(*l), GFP_NOFS);
460         if (NULL != l)
461                 btrfsic_block_link_init(l);
462 
463         return l;
464 }
465 
466 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
467 {
468         BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
469         kfree(l);
470 }
471 
472 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
473 {
474         ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
475         ds->bdev = NULL;
476         ds->state = NULL;
477         ds->name[0] = '\0';
478         INIT_LIST_HEAD(&ds->collision_resolving_node);
479         ds->last_flush_gen = 0;
480         btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
481         ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
482         ds->dummy_block_for_bio_bh_flush.dev_state = ds;
483 }
484 
485 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
486 {
487         struct btrfsic_dev_state *ds;
488 
489         ds = kzalloc(sizeof(*ds), GFP_NOFS);
490         if (NULL != ds)
491                 btrfsic_dev_state_init(ds);
492 
493         return ds;
494 }
495 
496 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
497 {
498         BUG_ON(!(NULL == ds ||
499                  BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
500         kfree(ds);
501 }
502 
503 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
504 {
505         int i;
506 
507         for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
508                 INIT_LIST_HEAD(h->table + i);
509 }
510 
511 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
512                                         struct btrfsic_block_hashtable *h)
513 {
514         const unsigned int hashval =
515             (((unsigned int)(b->dev_bytenr >> 16)) ^
516              ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
517              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
518 
519         list_add(&b->collision_resolving_node, h->table + hashval);
520 }
521 
522 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
523 {
524         list_del(&b->collision_resolving_node);
525 }
526 
527 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
528                 struct block_device *bdev,
529                 u64 dev_bytenr,
530                 struct btrfsic_block_hashtable *h)
531 {
532         const unsigned int hashval =
533             (((unsigned int)(dev_bytenr >> 16)) ^
534              ((unsigned int)((uintptr_t)bdev))) &
535              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
536         struct btrfsic_block *b;
537 
538         list_for_each_entry(b, h->table + hashval, collision_resolving_node) {
539                 if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
540                         return b;
541         }
542 
543         return NULL;
544 }
545 
546 static void btrfsic_block_link_hashtable_init(
547                 struct btrfsic_block_link_hashtable *h)
548 {
549         int i;
550 
551         for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
552                 INIT_LIST_HEAD(h->table + i);
553 }
554 
555 static void btrfsic_block_link_hashtable_add(
556                 struct btrfsic_block_link *l,
557                 struct btrfsic_block_link_hashtable *h)
558 {
559         const unsigned int hashval =
560             (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
561              ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
562              ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
563              ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
564              & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
565 
566         BUG_ON(NULL == l->block_ref_to);
567         BUG_ON(NULL == l->block_ref_from);
568         list_add(&l->collision_resolving_node, h->table + hashval);
569 }
570 
571 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
572 {
573         list_del(&l->collision_resolving_node);
574 }
575 
576 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
577                 struct block_device *bdev_ref_to,
578                 u64 dev_bytenr_ref_to,
579                 struct block_device *bdev_ref_from,
580                 u64 dev_bytenr_ref_from,
581                 struct btrfsic_block_link_hashtable *h)
582 {
583         const unsigned int hashval =
584             (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
585              ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
586              ((unsigned int)((uintptr_t)bdev_ref_to)) ^
587              ((unsigned int)((uintptr_t)bdev_ref_from))) &
588              (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
589         struct btrfsic_block_link *l;
590 
591         list_for_each_entry(l, h->table + hashval, collision_resolving_node) {
592                 BUG_ON(NULL == l->block_ref_to);
593                 BUG_ON(NULL == l->block_ref_from);
594                 if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
595                     l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
596                     l->block_ref_from->dev_state->bdev == bdev_ref_from &&
597                     l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
598                         return l;
599         }
600 
601         return NULL;
602 }
603 
604 static void btrfsic_dev_state_hashtable_init(
605                 struct btrfsic_dev_state_hashtable *h)
606 {
607         int i;
608 
609         for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
610                 INIT_LIST_HEAD(h->table + i);
611 }
612 
613 static void btrfsic_dev_state_hashtable_add(
614                 struct btrfsic_dev_state *ds,
615                 struct btrfsic_dev_state_hashtable *h)
616 {
617         const unsigned int hashval =
618             (((unsigned int)((uintptr_t)ds->bdev)) &
619              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
620 
621         list_add(&ds->collision_resolving_node, h->table + hashval);
622 }
623 
624 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
625 {
626         list_del(&ds->collision_resolving_node);
627 }
628 
629 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
630                 struct block_device *bdev,
631                 struct btrfsic_dev_state_hashtable *h)
632 {
633         const unsigned int hashval =
634             (((unsigned int)((uintptr_t)bdev)) &
635              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
636         struct btrfsic_dev_state *ds;
637 
638         list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
639                 if (ds->bdev == bdev)
640                         return ds;
641         }
642 
643         return NULL;
644 }
645 
646 static int btrfsic_process_superblock(struct btrfsic_state *state,
647                                       struct btrfs_fs_devices *fs_devices)
648 {
649         int ret = 0;
650         struct btrfs_super_block *selected_super;
651         struct list_head *dev_head = &fs_devices->devices;
652         struct btrfs_device *device;
653         struct btrfsic_dev_state *selected_dev_state = NULL;
654         int pass;
655 
656         BUG_ON(NULL == state);
657         selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
658         if (NULL == selected_super) {
659                 printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
660                 return -ENOMEM;
661         }
662 
663         list_for_each_entry(device, dev_head, dev_list) {
664                 int i;
665                 struct btrfsic_dev_state *dev_state;
666 
667                 if (!device->bdev || !device->name)
668                         continue;
669 
670                 dev_state = btrfsic_dev_state_lookup(device->bdev);
671                 BUG_ON(NULL == dev_state);
672                 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
673                         ret = btrfsic_process_superblock_dev_mirror(
674                                         state, dev_state, device, i,
675                                         &selected_dev_state, selected_super);
676                         if (0 != ret && 0 == i) {
677                                 kfree(selected_super);
678                                 return ret;
679                         }
680                 }
681         }
682 
683         if (NULL == state->latest_superblock) {
684                 printk(KERN_INFO "btrfsic: no superblock found!\n");
685                 kfree(selected_super);
686                 return -1;
687         }
688 
689         state->csum_size = btrfs_super_csum_size(selected_super);
690 
691         for (pass = 0; pass < 3; pass++) {
692                 int num_copies;
693                 int mirror_num;
694                 u64 next_bytenr;
695 
696                 switch (pass) {
697                 case 0:
698                         next_bytenr = btrfs_super_root(selected_super);
699                         if (state->print_mask &
700                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
701                                 printk(KERN_INFO "root@%llu\n", next_bytenr);
702                         break;
703                 case 1:
704                         next_bytenr = btrfs_super_chunk_root(selected_super);
705                         if (state->print_mask &
706                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
707                                 printk(KERN_INFO "chunk@%llu\n", next_bytenr);
708                         break;
709                 case 2:
710                         next_bytenr = btrfs_super_log_root(selected_super);
711                         if (0 == next_bytenr)
712                                 continue;
713                         if (state->print_mask &
714                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
715                                 printk(KERN_INFO "log@%llu\n", next_bytenr);
716                         break;
717                 }
718 
719                 num_copies =
720                     btrfs_num_copies(state->root->fs_info,
721                                      next_bytenr, state->metablock_size);
722                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
723                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
724                                next_bytenr, num_copies);
725 
726                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
727                         struct btrfsic_block *next_block;
728                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
729                         struct btrfsic_block_link *l;
730 
731                         ret = btrfsic_map_block(state, next_bytenr,
732                                                 state->metablock_size,
733                                                 &tmp_next_block_ctx,
734                                                 mirror_num);
735                         if (ret) {
736                                 printk(KERN_INFO "btrfsic:"
737                                        " btrfsic_map_block(root @%llu,"
738                                        " mirror %d) failed!\n",
739                                        next_bytenr, mirror_num);
740                                 kfree(selected_super);
741                                 return -1;
742                         }
743 
744                         next_block = btrfsic_block_hashtable_lookup(
745                                         tmp_next_block_ctx.dev->bdev,
746                                         tmp_next_block_ctx.dev_bytenr,
747                                         &state->block_hashtable);
748                         BUG_ON(NULL == next_block);
749 
750                         l = btrfsic_block_link_hashtable_lookup(
751                                         tmp_next_block_ctx.dev->bdev,
752                                         tmp_next_block_ctx.dev_bytenr,
753                                         state->latest_superblock->dev_state->
754                                         bdev,
755                                         state->latest_superblock->dev_bytenr,
756                                         &state->block_link_hashtable);
757                         BUG_ON(NULL == l);
758 
759                         ret = btrfsic_read_block(state, &tmp_next_block_ctx);
760                         if (ret < (int)PAGE_SIZE) {
761                                 printk(KERN_INFO
762                                        "btrfsic: read @logical %llu failed!\n",
763                                        tmp_next_block_ctx.start);
764                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
765                                 kfree(selected_super);
766                                 return -1;
767                         }
768 
769                         ret = btrfsic_process_metablock(state,
770                                                         next_block,
771                                                         &tmp_next_block_ctx,
772                                                         BTRFS_MAX_LEVEL + 3, 1);
773                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
774                 }
775         }
776 
777         kfree(selected_super);
778         return ret;
779 }
780 
781 static int btrfsic_process_superblock_dev_mirror(
782                 struct btrfsic_state *state,
783                 struct btrfsic_dev_state *dev_state,
784                 struct btrfs_device *device,
785                 int superblock_mirror_num,
786                 struct btrfsic_dev_state **selected_dev_state,
787                 struct btrfs_super_block *selected_super)
788 {
789         struct btrfs_super_block *super_tmp;
790         u64 dev_bytenr;
791         struct buffer_head *bh;
792         struct btrfsic_block *superblock_tmp;
793         int pass;
794         struct block_device *const superblock_bdev = device->bdev;
795 
796         /* super block bytenr is always the unmapped device bytenr */
797         dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
798         if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
799                 return -1;
800         bh = __bread(superblock_bdev, dev_bytenr / 4096,
801                      BTRFS_SUPER_INFO_SIZE);
802         if (NULL == bh)
803                 return -1;
804         super_tmp = (struct btrfs_super_block *)
805             (bh->b_data + (dev_bytenr & 4095));
806 
807         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
808             btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
809             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
810             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
811             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
812                 brelse(bh);
813                 return 0;
814         }
815 
816         superblock_tmp =
817             btrfsic_block_hashtable_lookup(superblock_bdev,
818                                            dev_bytenr,
819                                            &state->block_hashtable);
820         if (NULL == superblock_tmp) {
821                 superblock_tmp = btrfsic_block_alloc();
822                 if (NULL == superblock_tmp) {
823                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
824                         brelse(bh);
825                         return -1;
826                 }
827                 /* for superblock, only the dev_bytenr makes sense */
828                 superblock_tmp->dev_bytenr = dev_bytenr;
829                 superblock_tmp->dev_state = dev_state;
830                 superblock_tmp->logical_bytenr = dev_bytenr;
831                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
832                 superblock_tmp->is_metadata = 1;
833                 superblock_tmp->is_superblock = 1;
834                 superblock_tmp->is_iodone = 1;
835                 superblock_tmp->never_written = 0;
836                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
837                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
838                         btrfs_info_in_rcu(device->dev_root->fs_info,
839                                 "new initial S-block (bdev %p, %s) @%llu (%s/%llu/%d)",
840                                      superblock_bdev,
841                                      rcu_str_deref(device->name), dev_bytenr,
842                                      dev_state->name, dev_bytenr,
843                                      superblock_mirror_num);
844                 list_add(&superblock_tmp->all_blocks_node,
845                          &state->all_blocks_list);
846                 btrfsic_block_hashtable_add(superblock_tmp,
847                                             &state->block_hashtable);
848         }
849 
850         /* select the one with the highest generation field */
851         if (btrfs_super_generation(super_tmp) >
852             state->max_superblock_generation ||
853             0 == state->max_superblock_generation) {
854                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
855                 *selected_dev_state = dev_state;
856                 state->max_superblock_generation =
857                     btrfs_super_generation(super_tmp);
858                 state->latest_superblock = superblock_tmp;
859         }
860 
861         for (pass = 0; pass < 3; pass++) {
862                 u64 next_bytenr;
863                 int num_copies;
864                 int mirror_num;
865                 const char *additional_string = NULL;
866                 struct btrfs_disk_key tmp_disk_key;
867 
868                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
869                 tmp_disk_key.offset = 0;
870                 switch (pass) {
871                 case 0:
872                         btrfs_set_disk_key_objectid(&tmp_disk_key,
873                                                     BTRFS_ROOT_TREE_OBJECTID);
874                         additional_string = "initial root ";
875                         next_bytenr = btrfs_super_root(super_tmp);
876                         break;
877                 case 1:
878                         btrfs_set_disk_key_objectid(&tmp_disk_key,
879                                                     BTRFS_CHUNK_TREE_OBJECTID);
880                         additional_string = "initial chunk ";
881                         next_bytenr = btrfs_super_chunk_root(super_tmp);
882                         break;
883                 case 2:
884                         btrfs_set_disk_key_objectid(&tmp_disk_key,
885                                                     BTRFS_TREE_LOG_OBJECTID);
886                         additional_string = "initial log ";
887                         next_bytenr = btrfs_super_log_root(super_tmp);
888                         if (0 == next_bytenr)
889                                 continue;
890                         break;
891                 }
892 
893                 num_copies =
894                     btrfs_num_copies(state->root->fs_info,
895                                      next_bytenr, state->metablock_size);
896                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
897                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
898                                next_bytenr, num_copies);
899                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
900                         struct btrfsic_block *next_block;
901                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
902                         struct btrfsic_block_link *l;
903 
904                         if (btrfsic_map_block(state, next_bytenr,
905                                               state->metablock_size,
906                                               &tmp_next_block_ctx,
907                                               mirror_num)) {
908                                 printk(KERN_INFO "btrfsic: btrfsic_map_block("
909                                        "bytenr @%llu, mirror %d) failed!\n",
910                                        next_bytenr, mirror_num);
911                                 brelse(bh);
912                                 return -1;
913                         }
914 
915                         next_block = btrfsic_block_lookup_or_add(
916                                         state, &tmp_next_block_ctx,
917                                         additional_string, 1, 1, 0,
918                                         mirror_num, NULL);
919                         if (NULL == next_block) {
920                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
921                                 brelse(bh);
922                                 return -1;
923                         }
924 
925                         next_block->disk_key = tmp_disk_key;
926                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
927                         l = btrfsic_block_link_lookup_or_add(
928                                         state, &tmp_next_block_ctx,
929                                         next_block, superblock_tmp,
930                                         BTRFSIC_GENERATION_UNKNOWN);
931                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
932                         if (NULL == l) {
933                                 brelse(bh);
934                                 return -1;
935                         }
936                 }
937         }
938         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
939                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
940 
941         brelse(bh);
942         return 0;
943 }
944 
945 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
946 {
947         struct btrfsic_stack_frame *sf;
948 
949         sf = kzalloc(sizeof(*sf), GFP_NOFS);
950         if (NULL == sf)
951                 printk(KERN_INFO "btrfsic: alloc memory failed!\n");
952         else
953                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
954         return sf;
955 }
956 
957 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
958 {
959         BUG_ON(!(NULL == sf ||
960                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
961         kfree(sf);
962 }
963 
964 static int btrfsic_process_metablock(
965                 struct btrfsic_state *state,
966                 struct btrfsic_block *const first_block,
967                 struct btrfsic_block_data_ctx *const first_block_ctx,
968                 int first_limit_nesting, int force_iodone_flag)
969 {
970         struct btrfsic_stack_frame initial_stack_frame = { 0 };
971         struct btrfsic_stack_frame *sf;
972         struct btrfsic_stack_frame *next_stack;
973         struct btrfs_header *const first_hdr =
974                 (struct btrfs_header *)first_block_ctx->datav[0];
975 
976         BUG_ON(!first_hdr);
977         sf = &initial_stack_frame;
978         sf->error = 0;
979         sf->i = -1;
980         sf->limit_nesting = first_limit_nesting;
981         sf->block = first_block;
982         sf->block_ctx = first_block_ctx;
983         sf->next_block = NULL;
984         sf->hdr = first_hdr;
985         sf->prev = NULL;
986 
987 continue_with_new_stack_frame:
988         sf->block->generation = le64_to_cpu(sf->hdr->generation);
989         if (0 == sf->hdr->level) {
990                 struct btrfs_leaf *const leafhdr =
991                     (struct btrfs_leaf *)sf->hdr;
992 
993                 if (-1 == sf->i) {
994                         sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
995 
996                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
997                                 printk(KERN_INFO
998                                        "leaf %llu items %d generation %llu"
999                                        " owner %llu\n",
1000                                        sf->block_ctx->start, sf->nr,
1001                                        btrfs_stack_header_generation(
1002                                                &leafhdr->header),
1003                                        btrfs_stack_header_owner(
1004                                                &leafhdr->header));
1005                 }
1006 
1007 continue_with_current_leaf_stack_frame:
1008                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1009                         sf->i++;
1010                         sf->num_copies = 0;
1011                 }
1012 
1013                 if (sf->i < sf->nr) {
1014                         struct btrfs_item disk_item;
1015                         u32 disk_item_offset =
1016                                 (uintptr_t)(leafhdr->items + sf->i) -
1017                                 (uintptr_t)leafhdr;
1018                         struct btrfs_disk_key *disk_key;
1019                         u8 type;
1020                         u32 item_offset;
1021                         u32 item_size;
1022 
1023                         if (disk_item_offset + sizeof(struct btrfs_item) >
1024                             sf->block_ctx->len) {
1025 leaf_item_out_of_bounce_error:
1026                                 printk(KERN_INFO
1027                                        "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1028                                        sf->block_ctx->start,
1029                                        sf->block_ctx->dev->name);
1030                                 goto one_stack_frame_backwards;
1031                         }
1032                         btrfsic_read_from_block_data(sf->block_ctx,
1033                                                      &disk_item,
1034                                                      disk_item_offset,
1035                                                      sizeof(struct btrfs_item));
1036                         item_offset = btrfs_stack_item_offset(&disk_item);
1037                         item_size = btrfs_stack_item_size(&disk_item);
1038                         disk_key = &disk_item.key;
1039                         type = btrfs_disk_key_type(disk_key);
1040 
1041                         if (BTRFS_ROOT_ITEM_KEY == type) {
1042                                 struct btrfs_root_item root_item;
1043                                 u32 root_item_offset;
1044                                 u64 next_bytenr;
1045 
1046                                 root_item_offset = item_offset +
1047                                         offsetof(struct btrfs_leaf, items);
1048                                 if (root_item_offset + item_size >
1049                                     sf->block_ctx->len)
1050                                         goto leaf_item_out_of_bounce_error;
1051                                 btrfsic_read_from_block_data(
1052                                         sf->block_ctx, &root_item,
1053                                         root_item_offset,
1054                                         item_size);
1055                                 next_bytenr = btrfs_root_bytenr(&root_item);
1056 
1057                                 sf->error =
1058                                     btrfsic_create_link_to_next_block(
1059                                                 state,
1060                                                 sf->block,
1061                                                 sf->block_ctx,
1062                                                 next_bytenr,
1063                                                 sf->limit_nesting,
1064                                                 &sf->next_block_ctx,
1065                                                 &sf->next_block,
1066                                                 force_iodone_flag,
1067                                                 &sf->num_copies,
1068                                                 &sf->mirror_num,
1069                                                 disk_key,
1070                                                 btrfs_root_generation(
1071                                                 &root_item));
1072                                 if (sf->error)
1073                                         goto one_stack_frame_backwards;
1074 
1075                                 if (NULL != sf->next_block) {
1076                                         struct btrfs_header *const next_hdr =
1077                                             (struct btrfs_header *)
1078                                             sf->next_block_ctx.datav[0];
1079 
1080                                         next_stack =
1081                                             btrfsic_stack_frame_alloc();
1082                                         if (NULL == next_stack) {
1083                                                 sf->error = -1;
1084                                                 btrfsic_release_block_ctx(
1085                                                                 &sf->
1086                                                                 next_block_ctx);
1087                                                 goto one_stack_frame_backwards;
1088                                         }
1089 
1090                                         next_stack->i = -1;
1091                                         next_stack->block = sf->next_block;
1092                                         next_stack->block_ctx =
1093                                             &sf->next_block_ctx;
1094                                         next_stack->next_block = NULL;
1095                                         next_stack->hdr = next_hdr;
1096                                         next_stack->limit_nesting =
1097                                             sf->limit_nesting - 1;
1098                                         next_stack->prev = sf;
1099                                         sf = next_stack;
1100                                         goto continue_with_new_stack_frame;
1101                                 }
1102                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1103                                    state->include_extent_data) {
1104                                 sf->error = btrfsic_handle_extent_data(
1105                                                 state,
1106                                                 sf->block,
1107                                                 sf->block_ctx,
1108                                                 item_offset,
1109                                                 force_iodone_flag);
1110                                 if (sf->error)
1111                                         goto one_stack_frame_backwards;
1112                         }
1113 
1114                         goto continue_with_current_leaf_stack_frame;
1115                 }
1116         } else {
1117                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1118 
1119                 if (-1 == sf->i) {
1120                         sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1121 
1122                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1123                                 printk(KERN_INFO "node %llu level %d items %d"
1124                                        " generation %llu owner %llu\n",
1125                                        sf->block_ctx->start,
1126                                        nodehdr->header.level, sf->nr,
1127                                        btrfs_stack_header_generation(
1128                                        &nodehdr->header),
1129                                        btrfs_stack_header_owner(
1130                                        &nodehdr->header));
1131                 }
1132 
1133 continue_with_current_node_stack_frame:
1134                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1135                         sf->i++;
1136                         sf->num_copies = 0;
1137                 }
1138 
1139                 if (sf->i < sf->nr) {
1140                         struct btrfs_key_ptr key_ptr;
1141                         u32 key_ptr_offset;
1142                         u64 next_bytenr;
1143 
1144                         key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1145                                           (uintptr_t)nodehdr;
1146                         if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1147                             sf->block_ctx->len) {
1148                                 printk(KERN_INFO
1149                                        "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1150                                        sf->block_ctx->start,
1151                                        sf->block_ctx->dev->name);
1152                                 goto one_stack_frame_backwards;
1153                         }
1154                         btrfsic_read_from_block_data(
1155                                 sf->block_ctx, &key_ptr, key_ptr_offset,
1156                                 sizeof(struct btrfs_key_ptr));
1157                         next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1158 
1159                         sf->error = btrfsic_create_link_to_next_block(
1160                                         state,
1161                                         sf->block,
1162                                         sf->block_ctx,
1163                                         next_bytenr,
1164                                         sf->limit_nesting,
1165                                         &sf->next_block_ctx,
1166                                         &sf->next_block,
1167                                         force_iodone_flag,
1168                                         &sf->num_copies,
1169                                         &sf->mirror_num,
1170                                         &key_ptr.key,
1171                                         btrfs_stack_key_generation(&key_ptr));
1172                         if (sf->error)
1173                                 goto one_stack_frame_backwards;
1174 
1175                         if (NULL != sf->next_block) {
1176                                 struct btrfs_header *const next_hdr =
1177                                     (struct btrfs_header *)
1178                                     sf->next_block_ctx.datav[0];
1179 
1180                                 next_stack = btrfsic_stack_frame_alloc();
1181                                 if (NULL == next_stack) {
1182                                         sf->error = -1;
1183                                         goto one_stack_frame_backwards;
1184                                 }
1185 
1186                                 next_stack->i = -1;
1187                                 next_stack->block = sf->next_block;
1188                                 next_stack->block_ctx = &sf->next_block_ctx;
1189                                 next_stack->next_block = NULL;
1190                                 next_stack->hdr = next_hdr;
1191                                 next_stack->limit_nesting =
1192                                     sf->limit_nesting - 1;
1193                                 next_stack->prev = sf;
1194                                 sf = next_stack;
1195                                 goto continue_with_new_stack_frame;
1196                         }
1197 
1198                         goto continue_with_current_node_stack_frame;
1199                 }
1200         }
1201 
1202 one_stack_frame_backwards:
1203         if (NULL != sf->prev) {
1204                 struct btrfsic_stack_frame *const prev = sf->prev;
1205 
1206                 /* the one for the initial block is freed in the caller */
1207                 btrfsic_release_block_ctx(sf->block_ctx);
1208 
1209                 if (sf->error) {
1210                         prev->error = sf->error;
1211                         btrfsic_stack_frame_free(sf);
1212                         sf = prev;
1213                         goto one_stack_frame_backwards;
1214                 }
1215 
1216                 btrfsic_stack_frame_free(sf);
1217                 sf = prev;
1218                 goto continue_with_new_stack_frame;
1219         } else {
1220                 BUG_ON(&initial_stack_frame != sf);
1221         }
1222 
1223         return sf->error;
1224 }
1225 
1226 static void btrfsic_read_from_block_data(
1227         struct btrfsic_block_data_ctx *block_ctx,
1228         void *dstv, u32 offset, size_t len)
1229 {
1230         size_t cur;
1231         size_t offset_in_page;
1232         char *kaddr;
1233         char *dst = (char *)dstv;
1234         size_t start_offset = block_ctx->start & ((u64)PAGE_SIZE - 1);
1235         unsigned long i = (start_offset + offset) >> PAGE_SHIFT;
1236 
1237         WARN_ON(offset + len > block_ctx->len);
1238         offset_in_page = (start_offset + offset) & (PAGE_SIZE - 1);
1239 
1240         while (len > 0) {
1241                 cur = min(len, ((size_t)PAGE_SIZE - offset_in_page));
1242                 BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_SIZE));
1243                 kaddr = block_ctx->datav[i];
1244                 memcpy(dst, kaddr + offset_in_page, cur);
1245 
1246                 dst += cur;
1247                 len -= cur;
1248                 offset_in_page = 0;
1249                 i++;
1250         }
1251 }
1252 
1253 static int btrfsic_create_link_to_next_block(
1254                 struct btrfsic_state *state,
1255                 struct btrfsic_block *block,
1256                 struct btrfsic_block_data_ctx *block_ctx,
1257                 u64 next_bytenr,
1258                 int limit_nesting,
1259                 struct btrfsic_block_data_ctx *next_block_ctx,
1260                 struct btrfsic_block **next_blockp,
1261                 int force_iodone_flag,
1262                 int *num_copiesp, int *mirror_nump,
1263                 struct btrfs_disk_key *disk_key,
1264                 u64 parent_generation)
1265 {
1266         struct btrfsic_block *next_block = NULL;
1267         int ret;
1268         struct btrfsic_block_link *l;
1269         int did_alloc_block_link;
1270         int block_was_created;
1271 
1272         *next_blockp = NULL;
1273         if (0 == *num_copiesp) {
1274                 *num_copiesp =
1275                     btrfs_num_copies(state->root->fs_info,
1276                                      next_bytenr, state->metablock_size);
1277                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1278                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1279                                next_bytenr, *num_copiesp);
1280                 *mirror_nump = 1;
1281         }
1282 
1283         if (*mirror_nump > *num_copiesp)
1284                 return 0;
1285 
1286         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1287                 printk(KERN_INFO
1288                        "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1289                        *mirror_nump);
1290         ret = btrfsic_map_block(state, next_bytenr,
1291                                 state->metablock_size,
1292                                 next_block_ctx, *mirror_nump);
1293         if (ret) {
1294                 printk(KERN_INFO
1295                        "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1296                        next_bytenr, *mirror_nump);
1297                 btrfsic_release_block_ctx(next_block_ctx);
1298                 *next_blockp = NULL;
1299                 return -1;
1300         }
1301 
1302         next_block = btrfsic_block_lookup_or_add(state,
1303                                                  next_block_ctx, "referenced ",
1304                                                  1, force_iodone_flag,
1305                                                  !force_iodone_flag,
1306                                                  *mirror_nump,
1307                                                  &block_was_created);
1308         if (NULL == next_block) {
1309                 btrfsic_release_block_ctx(next_block_ctx);
1310                 *next_blockp = NULL;
1311                 return -1;
1312         }
1313         if (block_was_created) {
1314                 l = NULL;
1315                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1316         } else {
1317                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1318                         if (next_block->logical_bytenr != next_bytenr &&
1319                             !(!next_block->is_metadata &&
1320                               0 == next_block->logical_bytenr))
1321                                 printk(KERN_INFO
1322                                        "Referenced block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1323                                        next_bytenr, next_block_ctx->dev->name,
1324                                        next_block_ctx->dev_bytenr, *mirror_nump,
1325                                        btrfsic_get_block_type(state,
1326                                                               next_block),
1327                                        next_block->logical_bytenr);
1328                         else
1329                                 printk(KERN_INFO
1330                                        "Referenced block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1331                                        next_bytenr, next_block_ctx->dev->name,
1332                                        next_block_ctx->dev_bytenr, *mirror_nump,
1333                                        btrfsic_get_block_type(state,
1334                                                               next_block));
1335                 }
1336                 next_block->logical_bytenr = next_bytenr;
1337 
1338                 next_block->mirror_num = *mirror_nump;
1339                 l = btrfsic_block_link_hashtable_lookup(
1340                                 next_block_ctx->dev->bdev,
1341                                 next_block_ctx->dev_bytenr,
1342                                 block_ctx->dev->bdev,
1343                                 block_ctx->dev_bytenr,
1344                                 &state->block_link_hashtable);
1345         }
1346 
1347         next_block->disk_key = *disk_key;
1348         if (NULL == l) {
1349                 l = btrfsic_block_link_alloc();
1350                 if (NULL == l) {
1351                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1352                         btrfsic_release_block_ctx(next_block_ctx);
1353                         *next_blockp = NULL;
1354                         return -1;
1355                 }
1356 
1357                 did_alloc_block_link = 1;
1358                 l->block_ref_to = next_block;
1359                 l->block_ref_from = block;
1360                 l->ref_cnt = 1;
1361                 l->parent_generation = parent_generation;
1362 
1363                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1364                         btrfsic_print_add_link(state, l);
1365 
1366                 list_add(&l->node_ref_to, &block->ref_to_list);
1367                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1368 
1369                 btrfsic_block_link_hashtable_add(l,
1370                                                  &state->block_link_hashtable);
1371         } else {
1372                 did_alloc_block_link = 0;
1373                 if (0 == limit_nesting) {
1374                         l->ref_cnt++;
1375                         l->parent_generation = parent_generation;
1376                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1377                                 btrfsic_print_add_link(state, l);
1378                 }
1379         }
1380 
1381         if (limit_nesting > 0 && did_alloc_block_link) {
1382                 ret = btrfsic_read_block(state, next_block_ctx);
1383                 if (ret < (int)next_block_ctx->len) {
1384                         printk(KERN_INFO
1385                                "btrfsic: read block @logical %llu failed!\n",
1386                                next_bytenr);
1387                         btrfsic_release_block_ctx(next_block_ctx);
1388                         *next_blockp = NULL;
1389                         return -1;
1390                 }
1391 
1392                 *next_blockp = next_block;
1393         } else {
1394                 *next_blockp = NULL;
1395         }
1396         (*mirror_nump)++;
1397 
1398         return 0;
1399 }
1400 
1401 static int btrfsic_handle_extent_data(
1402                 struct btrfsic_state *state,
1403                 struct btrfsic_block *block,
1404                 struct btrfsic_block_data_ctx *block_ctx,
1405                 u32 item_offset, int force_iodone_flag)
1406 {
1407         int ret;
1408         struct btrfs_file_extent_item file_extent_item;
1409         u64 file_extent_item_offset;
1410         u64 next_bytenr;
1411         u64 num_bytes;
1412         u64 generation;
1413         struct btrfsic_block_link *l;
1414 
1415         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1416                                   item_offset;
1417         if (file_extent_item_offset +
1418             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1419             block_ctx->len) {
1420                 printk(KERN_INFO
1421                        "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1422                        block_ctx->start, block_ctx->dev->name);
1423                 return -1;
1424         }
1425 
1426         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1427                 file_extent_item_offset,
1428                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1429         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1430             btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1431                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1432                         printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1433                                file_extent_item.type,
1434                                btrfs_stack_file_extent_disk_bytenr(
1435                                &file_extent_item));
1436                 return 0;
1437         }
1438 
1439         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1440             block_ctx->len) {
1441                 printk(KERN_INFO
1442                        "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1443                        block_ctx->start, block_ctx->dev->name);
1444                 return -1;
1445         }
1446         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1447                                      file_extent_item_offset,
1448                                      sizeof(struct btrfs_file_extent_item));
1449         next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1450         if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1451             BTRFS_COMPRESS_NONE) {
1452                 next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1453                 num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1454         } else {
1455                 num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1456         }
1457         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1458 
1459         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1460                 printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1461                        " offset = %llu, num_bytes = %llu\n",
1462                        file_extent_item.type,
1463                        btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1464                        btrfs_stack_file_extent_offset(&file_extent_item),
1465                        num_bytes);
1466         while (num_bytes > 0) {
1467                 u32 chunk_len;
1468                 int num_copies;
1469                 int mirror_num;
1470 
1471                 if (num_bytes > state->datablock_size)
1472                         chunk_len = state->datablock_size;
1473                 else
1474                         chunk_len = num_bytes;
1475 
1476                 num_copies =
1477                     btrfs_num_copies(state->root->fs_info,
1478                                      next_bytenr, state->datablock_size);
1479                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1480                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1481                                next_bytenr, num_copies);
1482                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1483                         struct btrfsic_block_data_ctx next_block_ctx;
1484                         struct btrfsic_block *next_block;
1485                         int block_was_created;
1486 
1487                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1488                                 printk(KERN_INFO "btrfsic_handle_extent_data("
1489                                        "mirror_num=%d)\n", mirror_num);
1490                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1491                                 printk(KERN_INFO
1492                                        "\tdisk_bytenr = %llu, num_bytes %u\n",
1493                                        next_bytenr, chunk_len);
1494                         ret = btrfsic_map_block(state, next_bytenr,
1495                                                 chunk_len, &next_block_ctx,
1496                                                 mirror_num);
1497                         if (ret) {
1498                                 printk(KERN_INFO
1499                                        "btrfsic: btrfsic_map_block(@%llu,"
1500                                        " mirror=%d) failed!\n",
1501                                        next_bytenr, mirror_num);
1502                                 return -1;
1503                         }
1504 
1505                         next_block = btrfsic_block_lookup_or_add(
1506                                         state,
1507                                         &next_block_ctx,
1508                                         "referenced ",
1509                                         0,
1510                                         force_iodone_flag,
1511                                         !force_iodone_flag,
1512                                         mirror_num,
1513                                         &block_was_created);
1514                         if (NULL == next_block) {
1515                                 printk(KERN_INFO
1516                                        "btrfsic: error, kmalloc failed!\n");
1517                                 btrfsic_release_block_ctx(&next_block_ctx);
1518                                 return -1;
1519                         }
1520                         if (!block_was_created) {
1521                                 if ((state->print_mask &
1522                                      BTRFSIC_PRINT_MASK_VERBOSE) &&
1523                                     next_block->logical_bytenr != next_bytenr &&
1524                                     !(!next_block->is_metadata &&
1525                                       0 == next_block->logical_bytenr)) {
1526                                         printk(KERN_INFO
1527                                                "Referenced block"
1528                                                " @%llu (%s/%llu/%d)"
1529                                                " found in hash table, D,"
1530                                                " bytenr mismatch"
1531                                                " (!= stored %llu).\n",
1532                                                next_bytenr,
1533                                                next_block_ctx.dev->name,
1534                                                next_block_ctx.dev_bytenr,
1535                                                mirror_num,
1536                                                next_block->logical_bytenr);
1537                                 }
1538                                 next_block->logical_bytenr = next_bytenr;
1539                                 next_block->mirror_num = mirror_num;
1540                         }
1541 
1542                         l = btrfsic_block_link_lookup_or_add(state,
1543                                                              &next_block_ctx,
1544                                                              next_block, block,
1545                                                              generation);
1546                         btrfsic_release_block_ctx(&next_block_ctx);
1547                         if (NULL == l)
1548                                 return -1;
1549                 }
1550 
1551                 next_bytenr += chunk_len;
1552                 num_bytes -= chunk_len;
1553         }
1554 
1555         return 0;
1556 }
1557 
1558 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1559                              struct btrfsic_block_data_ctx *block_ctx_out,
1560                              int mirror_num)
1561 {
1562         int ret;
1563         u64 length;
1564         struct btrfs_bio *multi = NULL;
1565         struct btrfs_device *device;
1566 
1567         length = len;
1568         ret = btrfs_map_block(state->root->fs_info, READ,
1569                               bytenr, &length, &multi, mirror_num);
1570 
1571         if (ret) {
1572                 block_ctx_out->start = 0;
1573                 block_ctx_out->dev_bytenr = 0;
1574                 block_ctx_out->len = 0;
1575                 block_ctx_out->dev = NULL;
1576                 block_ctx_out->datav = NULL;
1577                 block_ctx_out->pagev = NULL;
1578                 block_ctx_out->mem_to_free = NULL;
1579 
1580                 return ret;
1581         }
1582 
1583         device = multi->stripes[0].dev;
1584         block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1585         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1586         block_ctx_out->start = bytenr;
1587         block_ctx_out->len = len;
1588         block_ctx_out->datav = NULL;
1589         block_ctx_out->pagev = NULL;
1590         block_ctx_out->mem_to_free = NULL;
1591 
1592         kfree(multi);
1593         if (NULL == block_ctx_out->dev) {
1594                 ret = -ENXIO;
1595                 printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1596         }
1597 
1598         return ret;
1599 }
1600 
1601 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1602 {
1603         if (block_ctx->mem_to_free) {
1604                 unsigned int num_pages;
1605 
1606                 BUG_ON(!block_ctx->datav);
1607                 BUG_ON(!block_ctx->pagev);
1608                 num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1609                             PAGE_SHIFT;
1610                 while (num_pages > 0) {
1611                         num_pages--;
1612                         if (block_ctx->datav[num_pages]) {
1613                                 kunmap(block_ctx->pagev[num_pages]);
1614                                 block_ctx->datav[num_pages] = NULL;
1615                         }
1616                         if (block_ctx->pagev[num_pages]) {
1617                                 __free_page(block_ctx->pagev[num_pages]);
1618                                 block_ctx->pagev[num_pages] = NULL;
1619                         }
1620                 }
1621 
1622                 kfree(block_ctx->mem_to_free);
1623                 block_ctx->mem_to_free = NULL;
1624                 block_ctx->pagev = NULL;
1625                 block_ctx->datav = NULL;
1626         }
1627 }
1628 
1629 static int btrfsic_read_block(struct btrfsic_state *state,
1630                               struct btrfsic_block_data_ctx *block_ctx)
1631 {
1632         unsigned int num_pages;
1633         unsigned int i;
1634         u64 dev_bytenr;
1635         int ret;
1636 
1637         BUG_ON(block_ctx->datav);
1638         BUG_ON(block_ctx->pagev);
1639         BUG_ON(block_ctx->mem_to_free);
1640         if (block_ctx->dev_bytenr & ((u64)PAGE_SIZE - 1)) {
1641                 printk(KERN_INFO
1642                        "btrfsic: read_block() with unaligned bytenr %llu\n",
1643                        block_ctx->dev_bytenr);
1644                 return -1;
1645         }
1646 
1647         num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1648                     PAGE_SHIFT;
1649         block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1650                                           sizeof(*block_ctx->pagev)) *
1651                                          num_pages, GFP_NOFS);
1652         if (!block_ctx->mem_to_free)
1653                 return -ENOMEM;
1654         block_ctx->datav = block_ctx->mem_to_free;
1655         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1656         for (i = 0; i < num_pages; i++) {
1657                 block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1658                 if (!block_ctx->pagev[i])
1659                         return -1;
1660         }
1661 
1662         dev_bytenr = block_ctx->dev_bytenr;
1663         for (i = 0; i < num_pages;) {
1664                 struct bio *bio;
1665                 unsigned int j;
1666 
1667                 bio = btrfs_io_bio_alloc(GFP_NOFS, num_pages - i);
1668                 if (!bio) {
1669                         printk(KERN_INFO
1670                                "btrfsic: bio_alloc() for %u pages failed!\n",
1671                                num_pages - i);
1672                         return -1;
1673                 }
1674                 bio->bi_bdev = block_ctx->dev->bdev;
1675                 bio->bi_iter.bi_sector = dev_bytenr >> 9;
1676 
1677                 for (j = i; j < num_pages; j++) {
1678                         ret = bio_add_page(bio, block_ctx->pagev[j],
1679                                            PAGE_SIZE, 0);
1680                         if (PAGE_SIZE != ret)
1681                                 break;
1682                 }
1683                 if (j == i) {
1684                         printk(KERN_INFO
1685                                "btrfsic: error, failed to add a single page!\n");
1686                         return -1;
1687                 }
1688                 if (submit_bio_wait(READ, bio)) {
1689                         printk(KERN_INFO
1690                                "btrfsic: read error at logical %llu dev %s!\n",
1691                                block_ctx->start, block_ctx->dev->name);
1692                         bio_put(bio);
1693                         return -1;
1694                 }
1695                 bio_put(bio);
1696                 dev_bytenr += (j - i) * PAGE_SIZE;
1697                 i = j;
1698         }
1699         for (i = 0; i < num_pages; i++) {
1700                 block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1701                 if (!block_ctx->datav[i]) {
1702                         printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1703                                block_ctx->dev->name);
1704                         return -1;
1705                 }
1706         }
1707 
1708         return block_ctx->len;
1709 }
1710 
1711 static void btrfsic_dump_database(struct btrfsic_state *state)
1712 {
1713         const struct btrfsic_block *b_all;
1714 
1715         BUG_ON(NULL == state);
1716 
1717         printk(KERN_INFO "all_blocks_list:\n");
1718         list_for_each_entry(b_all, &state->all_blocks_list, all_blocks_node) {
1719                 const struct btrfsic_block_link *l;
1720 
1721                 printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1722                        btrfsic_get_block_type(state, b_all),
1723                        b_all->logical_bytenr, b_all->dev_state->name,
1724                        b_all->dev_bytenr, b_all->mirror_num);
1725 
1726                 list_for_each_entry(l, &b_all->ref_to_list, node_ref_to) {
1727                         printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1728                                " refers %u* to"
1729                                " %c @%llu (%s/%llu/%d)\n",
1730                                btrfsic_get_block_type(state, b_all),
1731                                b_all->logical_bytenr, b_all->dev_state->name,
1732                                b_all->dev_bytenr, b_all->mirror_num,
1733                                l->ref_cnt,
1734                                btrfsic_get_block_type(state, l->block_ref_to),
1735                                l->block_ref_to->logical_bytenr,
1736                                l->block_ref_to->dev_state->name,
1737                                l->block_ref_to->dev_bytenr,
1738                                l->block_ref_to->mirror_num);
1739                 }
1740 
1741                 list_for_each_entry(l, &b_all->ref_from_list, node_ref_from) {
1742                         printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1743                                " is ref %u* from"
1744                                " %c @%llu (%s/%llu/%d)\n",
1745                                btrfsic_get_block_type(state, b_all),
1746                                b_all->logical_bytenr, b_all->dev_state->name,
1747                                b_all->dev_bytenr, b_all->mirror_num,
1748                                l->ref_cnt,
1749                                btrfsic_get_block_type(state, l->block_ref_from),
1750                                l->block_ref_from->logical_bytenr,
1751                                l->block_ref_from->dev_state->name,
1752                                l->block_ref_from->dev_bytenr,
1753                                l->block_ref_from->mirror_num);
1754                 }
1755 
1756                 printk(KERN_INFO "\n");
1757         }
1758 }
1759 
1760 /*
1761  * Test whether the disk block contains a tree block (leaf or node)
1762  * (note that this test fails for the super block)
1763  */
1764 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1765                                      char **datav, unsigned int num_pages)
1766 {
1767         struct btrfs_header *h;
1768         u8 csum[BTRFS_CSUM_SIZE];
1769         u32 crc = ~(u32)0;
1770         unsigned int i;
1771 
1772         if (num_pages * PAGE_SIZE < state->metablock_size)
1773                 return 1; /* not metadata */
1774         num_pages = state->metablock_size >> PAGE_SHIFT;
1775         h = (struct btrfs_header *)datav[0];
1776 
1777         if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1778                 return 1;
1779 
1780         for (i = 0; i < num_pages; i++) {
1781                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1782                 size_t sublen = i ? PAGE_SIZE :
1783                                     (PAGE_SIZE - BTRFS_CSUM_SIZE);
1784 
1785                 crc = btrfs_crc32c(crc, data, sublen);
1786         }
1787         btrfs_csum_final(crc, csum);
1788         if (memcmp(csum, h->csum, state->csum_size))
1789                 return 1;
1790 
1791         return 0; /* is metadata */
1792 }
1793 
1794 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1795                                           u64 dev_bytenr, char **mapped_datav,
1796                                           unsigned int num_pages,
1797                                           struct bio *bio, int *bio_is_patched,
1798                                           struct buffer_head *bh,
1799                                           int submit_bio_bh_rw)
1800 {
1801         int is_metadata;
1802         struct btrfsic_block *block;
1803         struct btrfsic_block_data_ctx block_ctx;
1804         int ret;
1805         struct btrfsic_state *state = dev_state->state;
1806         struct block_device *bdev = dev_state->bdev;
1807         unsigned int processed_len;
1808 
1809         if (NULL != bio_is_patched)
1810                 *bio_is_patched = 0;
1811 
1812 again:
1813         if (num_pages == 0)
1814                 return;
1815 
1816         processed_len = 0;
1817         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1818                                                       num_pages));
1819 
1820         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1821                                                &state->block_hashtable);
1822         if (NULL != block) {
1823                 u64 bytenr = 0;
1824                 struct btrfsic_block_link *l, *tmp;
1825 
1826                 if (block->is_superblock) {
1827                         bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1828                                                     mapped_datav[0]);
1829                         if (num_pages * PAGE_SIZE <
1830                             BTRFS_SUPER_INFO_SIZE) {
1831                                 printk(KERN_INFO
1832                                        "btrfsic: cannot work with too short bios!\n");
1833                                 return;
1834                         }
1835                         is_metadata = 1;
1836                         BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_SIZE - 1));
1837                         processed_len = BTRFS_SUPER_INFO_SIZE;
1838                         if (state->print_mask &
1839                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1840                                 printk(KERN_INFO
1841                                        "[before new superblock is written]:\n");
1842                                 btrfsic_dump_tree_sub(state, block, 0);
1843                         }
1844                 }
1845                 if (is_metadata) {
1846                         if (!block->is_superblock) {
1847                                 if (num_pages * PAGE_SIZE <
1848                                     state->metablock_size) {
1849                                         printk(KERN_INFO
1850                                                "btrfsic: cannot work with too short bios!\n");
1851                                         return;
1852                                 }
1853                                 processed_len = state->metablock_size;
1854                                 bytenr = btrfs_stack_header_bytenr(
1855                                                 (struct btrfs_header *)
1856                                                 mapped_datav[0]);
1857                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1858                                                                dev_state,
1859                                                                dev_bytenr);
1860                         }
1861                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1862                                 if (block->logical_bytenr != bytenr &&
1863                                     !(!block->is_metadata &&
1864                                       block->logical_bytenr == 0))
1865                                         printk(KERN_INFO
1866                                                "Written block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1867                                                bytenr, dev_state->name,
1868                                                dev_bytenr,
1869                                                block->mirror_num,
1870                                                btrfsic_get_block_type(state,
1871                                                                       block),
1872                                                block->logical_bytenr);
1873                                 else
1874                                         printk(KERN_INFO
1875                                                "Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1876                                                bytenr, dev_state->name,
1877                                                dev_bytenr, block->mirror_num,
1878                                                btrfsic_get_block_type(state,
1879                                                                       block));
1880                         }
1881                         block->logical_bytenr = bytenr;
1882                 } else {
1883                         if (num_pages * PAGE_SIZE <
1884                             state->datablock_size) {
1885                                 printk(KERN_INFO
1886                                        "btrfsic: cannot work with too short bios!\n");
1887                                 return;
1888                         }
1889                         processed_len = state->datablock_size;
1890                         bytenr = block->logical_bytenr;
1891                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1892                                 printk(KERN_INFO
1893                                        "Written block @%llu (%s/%llu/%d)"
1894                                        " found in hash table, %c.\n",
1895                                        bytenr, dev_state->name, dev_bytenr,
1896                                        block->mirror_num,
1897                                        btrfsic_get_block_type(state, block));
1898                 }
1899 
1900                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1901                         printk(KERN_INFO
1902                                "ref_to_list: %cE, ref_from_list: %cE\n",
1903                                list_empty(&block->ref_to_list) ? ' ' : '!',
1904                                list_empty(&block->ref_from_list) ? ' ' : '!');
1905                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1906                         printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1907                                " @%llu (%s/%llu/%d), old(gen=%llu,"
1908                                " objectid=%llu, type=%d, offset=%llu),"
1909                                " new(gen=%llu),"
1910                                " which is referenced by most recent superblock"
1911                                " (superblockgen=%llu)!\n",
1912                                btrfsic_get_block_type(state, block), bytenr,
1913                                dev_state->name, dev_bytenr, block->mirror_num,
1914                                block->generation,
1915                                btrfs_disk_key_objectid(&block->disk_key),
1916                                block->disk_key.type,
1917                                btrfs_disk_key_offset(&block->disk_key),
1918                                btrfs_stack_header_generation(
1919                                        (struct btrfs_header *) mapped_datav[0]),
1920                                state->max_superblock_generation);
1921                         btrfsic_dump_tree(state);
1922                 }
1923 
1924                 if (!block->is_iodone && !block->never_written) {
1925                         printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1926                                " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
1927                                " which is not yet iodone!\n",
1928                                btrfsic_get_block_type(state, block), bytenr,
1929                                dev_state->name, dev_bytenr, block->mirror_num,
1930                                block->generation,
1931                                btrfs_stack_header_generation(
1932                                        (struct btrfs_header *)
1933                                        mapped_datav[0]));
1934                         /* it would not be safe to go on */
1935                         btrfsic_dump_tree(state);
1936                         goto continue_loop;
1937                 }
1938 
1939                 /*
1940                  * Clear all references of this block. Do not free
1941                  * the block itself even if is not referenced anymore
1942                  * because it still carries valueable information
1943                  * like whether it was ever written and IO completed.
1944                  */
1945                 list_for_each_entry_safe(l, tmp, &block->ref_to_list,
1946                                          node_ref_to) {
1947                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1948                                 btrfsic_print_rem_link(state, l);
1949                         l->ref_cnt--;
1950                         if (0 == l->ref_cnt) {
1951                                 list_del(&l->node_ref_to);
1952                                 list_del(&l->node_ref_from);
1953                                 btrfsic_block_link_hashtable_remove(l);
1954                                 btrfsic_block_link_free(l);
1955                         }
1956                 }
1957 
1958                 block_ctx.dev = dev_state;
1959                 block_ctx.dev_bytenr = dev_bytenr;
1960                 block_ctx.start = bytenr;
1961                 block_ctx.len = processed_len;
1962                 block_ctx.pagev = NULL;
1963                 block_ctx.mem_to_free = NULL;
1964                 block_ctx.datav = mapped_datav;
1965 
1966                 if (is_metadata || state->include_extent_data) {
1967                         block->never_written = 0;
1968                         block->iodone_w_error = 0;
1969                         if (NULL != bio) {
1970                                 block->is_iodone = 0;
1971                                 BUG_ON(NULL == bio_is_patched);
1972                                 if (!*bio_is_patched) {
1973                                         block->orig_bio_bh_private =
1974                                             bio->bi_private;
1975                                         block->orig_bio_bh_end_io.bio =
1976                                             bio->bi_end_io;
1977                                         block->next_in_same_bio = NULL;
1978                                         bio->bi_private = block;
1979                                         bio->bi_end_io = btrfsic_bio_end_io;
1980                                         *bio_is_patched = 1;
1981                                 } else {
1982                                         struct btrfsic_block *chained_block =
1983                                             (struct btrfsic_block *)
1984                                             bio->bi_private;
1985 
1986                                         BUG_ON(NULL == chained_block);
1987                                         block->orig_bio_bh_private =
1988                                             chained_block->orig_bio_bh_private;
1989                                         block->orig_bio_bh_end_io.bio =
1990                                             chained_block->orig_bio_bh_end_io.
1991                                             bio;
1992                                         block->next_in_same_bio = chained_block;
1993                                         bio->bi_private = block;
1994                                 }
1995                         } else if (NULL != bh) {
1996                                 block->is_iodone = 0;
1997                                 block->orig_bio_bh_private = bh->b_private;
1998                                 block->orig_bio_bh_end_io.bh = bh->b_end_io;
1999                                 block->next_in_same_bio = NULL;
2000                                 bh->b_private = block;
2001                                 bh->b_end_io = btrfsic_bh_end_io;
2002                         } else {
2003                                 block->is_iodone = 1;
2004                                 block->orig_bio_bh_private = NULL;
2005                                 block->orig_bio_bh_end_io.bio = NULL;
2006                                 block->next_in_same_bio = NULL;
2007                         }
2008                 }
2009 
2010                 block->flush_gen = dev_state->last_flush_gen + 1;
2011                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2012                 if (is_metadata) {
2013                         block->logical_bytenr = bytenr;
2014                         block->is_metadata = 1;
2015                         if (block->is_superblock) {
2016                                 BUG_ON(PAGE_SIZE !=
2017                                        BTRFS_SUPER_INFO_SIZE);
2018                                 ret = btrfsic_process_written_superblock(
2019                                                 state,
2020                                                 block,
2021                                                 (struct btrfs_super_block *)
2022                                                 mapped_datav[0]);
2023                                 if (state->print_mask &
2024                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2025                                         printk(KERN_INFO
2026                                         "[after new superblock is written]:\n");
2027                                         btrfsic_dump_tree_sub(state, block, 0);
2028                                 }
2029                         } else {
2030                                 block->mirror_num = 0;  /* unknown */
2031                                 ret = btrfsic_process_metablock(
2032                                                 state,
2033                                                 block,
2034                                                 &block_ctx,
2035                                                 0, 0);
2036                         }
2037                         if (ret)
2038                                 printk(KERN_INFO
2039                                        "btrfsic: btrfsic_process_metablock"
2040                                        "(root @%llu) failed!\n",
2041                                        dev_bytenr);
2042                 } else {
2043                         block->is_metadata = 0;
2044                         block->mirror_num = 0;  /* unknown */
2045                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
2046                         if (!state->include_extent_data
2047                             && list_empty(&block->ref_from_list)) {
2048                                 /*
2049                                  * disk block is overwritten with extent
2050                                  * data (not meta data) and we are configured
2051                                  * to not include extent data: take the
2052                                  * chance and free the block's memory
2053                                  */
2054                                 btrfsic_block_hashtable_remove(block);
2055                                 list_del(&block->all_blocks_node);
2056                                 btrfsic_block_free(block);
2057                         }
2058                 }
2059                 btrfsic_release_block_ctx(&block_ctx);
2060         } else {
2061                 /* block has not been found in hash table */
2062                 u64 bytenr;
2063 
2064                 if (!is_metadata) {
2065                         processed_len = state->datablock_size;
2066                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2067                                 printk(KERN_INFO "Written block (%s/%llu/?)"
2068                                        " !found in hash table, D.\n",
2069                                        dev_state->name, dev_bytenr);
2070                         if (!state->include_extent_data) {
2071                                 /* ignore that written D block */
2072                                 goto continue_loop;
2073                         }
2074 
2075                         /* this is getting ugly for the
2076                          * include_extent_data case... */
2077                         bytenr = 0;     /* unknown */
2078                 } else {
2079                         processed_len = state->metablock_size;
2080                         bytenr = btrfs_stack_header_bytenr(
2081                                         (struct btrfs_header *)
2082                                         mapped_datav[0]);
2083                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2084                                                        dev_bytenr);
2085                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2086                                 printk(KERN_INFO
2087                                        "Written block @%llu (%s/%llu/?)"
2088                                        " !found in hash table, M.\n",
2089                                        bytenr, dev_state->name, dev_bytenr);
2090                 }
2091 
2092                 block_ctx.dev = dev_state;
2093                 block_ctx.dev_bytenr = dev_bytenr;
2094                 block_ctx.start = bytenr;
2095                 block_ctx.len = processed_len;
2096                 block_ctx.pagev = NULL;
2097                 block_ctx.mem_to_free = NULL;
2098                 block_ctx.datav = mapped_datav;
2099 
2100                 block = btrfsic_block_alloc();
2101                 if (NULL == block) {
2102                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2103                         btrfsic_release_block_ctx(&block_ctx);
2104                         goto continue_loop;
2105                 }
2106                 block->dev_state = dev_state;
2107                 block->dev_bytenr = dev_bytenr;
2108                 block->logical_bytenr = bytenr;
2109                 block->is_metadata = is_metadata;
2110                 block->never_written = 0;
2111                 block->iodone_w_error = 0;
2112                 block->mirror_num = 0;  /* unknown */
2113                 block->flush_gen = dev_state->last_flush_gen + 1;
2114                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2115                 if (NULL != bio) {
2116                         block->is_iodone = 0;
2117                         BUG_ON(NULL == bio_is_patched);
2118                         if (!*bio_is_patched) {
2119                                 block->orig_bio_bh_private = bio->bi_private;
2120                                 block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2121                                 block->next_in_same_bio = NULL;
2122                                 bio->bi_private = block;
2123                                 bio->bi_end_io = btrfsic_bio_end_io;
2124                                 *bio_is_patched = 1;
2125                         } else {
2126                                 struct btrfsic_block *chained_block =
2127                                     (struct btrfsic_block *)
2128                                     bio->bi_private;
2129 
2130                                 BUG_ON(NULL == chained_block);
2131                                 block->orig_bio_bh_private =
2132                                     chained_block->orig_bio_bh_private;
2133                                 block->orig_bio_bh_end_io.bio =
2134                                     chained_block->orig_bio_bh_end_io.bio;
2135                                 block->next_in_same_bio = chained_block;
2136                                 bio->bi_private = block;
2137                         }
2138                 } else if (NULL != bh) {
2139                         block->is_iodone = 0;
2140                         block->orig_bio_bh_private = bh->b_private;
2141                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2142                         block->next_in_same_bio = NULL;
2143                         bh->b_private = block;
2144                         bh->b_end_io = btrfsic_bh_end_io;
2145                 } else {
2146                         block->is_iodone = 1;
2147                         block->orig_bio_bh_private = NULL;
2148                         block->orig_bio_bh_end_io.bio = NULL;
2149                         block->next_in_same_bio = NULL;
2150                 }
2151                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2152                         printk(KERN_INFO
2153                                "New written %c-block @%llu (%s/%llu/%d)\n",
2154                                is_metadata ? 'M' : 'D',
2155                                block->logical_bytenr, block->dev_state->name,
2156                                block->dev_bytenr, block->mirror_num);
2157                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2158                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2159 
2160                 if (is_metadata) {
2161                         ret = btrfsic_process_metablock(state, block,
2162                                                         &block_ctx, 0, 0);
2163                         if (ret)
2164                                 printk(KERN_INFO
2165                                        "btrfsic: process_metablock(root @%llu)"
2166                                        " failed!\n",
2167                                        dev_bytenr);
2168                 }
2169                 btrfsic_release_block_ctx(&block_ctx);
2170         }
2171 
2172 continue_loop:
2173         BUG_ON(!processed_len);
2174         dev_bytenr += processed_len;
2175         mapped_datav += processed_len >> PAGE_SHIFT;
2176         num_pages -= processed_len >> PAGE_SHIFT;
2177         goto again;
2178 }
2179 
2180 static void btrfsic_bio_end_io(struct bio *bp)
2181 {
2182         struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2183         int iodone_w_error;
2184 
2185         /* mutex is not held! This is not save if IO is not yet completed
2186          * on umount */
2187         iodone_w_error = 0;
2188         if (bp->bi_error)
2189                 iodone_w_error = 1;
2190 
2191         BUG_ON(NULL == block);
2192         bp->bi_private = block->orig_bio_bh_private;
2193         bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2194 
2195         do {
2196                 struct btrfsic_block *next_block;
2197                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2198 
2199                 if ((dev_state->state->print_mask &
2200                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2201                         printk(KERN_INFO
2202                                "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2203                                bp->bi_error,
2204                                btrfsic_get_block_type(dev_state->state, block),
2205                                block->logical_bytenr, dev_state->name,
2206                                block->dev_bytenr, block->mirror_num);
2207                 next_block = block->next_in_same_bio;
2208                 block->iodone_w_error = iodone_w_error;
2209                 if (block->submit_bio_bh_rw & REQ_FLUSH) {
2210                         dev_state->last_flush_gen++;
2211                         if ((dev_state->state->print_mask &
2212                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2213                                 printk(KERN_INFO
2214                                        "bio_end_io() new %s flush_gen=%llu\n",
2215                                        dev_state->name,
2216                                        dev_state->last_flush_gen);
2217                 }
2218                 if (block->submit_bio_bh_rw & REQ_FUA)
2219                         block->flush_gen = 0; /* FUA completed means block is
2220                                                * on disk */
2221                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2222                 block = next_block;
2223         } while (NULL != block);
2224 
2225         bp->bi_end_io(bp);
2226 }
2227 
2228 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2229 {
2230         struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2231         int iodone_w_error = !uptodate;
2232         struct btrfsic_dev_state *dev_state;
2233 
2234         BUG_ON(NULL == block);
2235         dev_state = block->dev_state;
2236         if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2237                 printk(KERN_INFO
2238                        "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2239                        iodone_w_error,
2240                        btrfsic_get_block_type(dev_state->state, block),
2241                        block->logical_bytenr, block->dev_state->name,
2242                        block->dev_bytenr, block->mirror_num);
2243 
2244         block->iodone_w_error = iodone_w_error;
2245         if (block->submit_bio_bh_rw & REQ_FLUSH) {
2246                 dev_state->last_flush_gen++;
2247                 if ((dev_state->state->print_mask &
2248                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2249                         printk(KERN_INFO
2250                                "bh_end_io() new %s flush_gen=%llu\n",
2251                                dev_state->name, dev_state->last_flush_gen);
2252         }
2253         if (block->submit_bio_bh_rw & REQ_FUA)
2254                 block->flush_gen = 0; /* FUA completed means block is on disk */
2255 
2256         bh->b_private = block->orig_bio_bh_private;
2257         bh->b_end_io = block->orig_bio_bh_end_io.bh;
2258         block->is_iodone = 1; /* for FLUSH, this releases the block */
2259         bh->b_end_io(bh, uptodate);
2260 }
2261 
2262 static int btrfsic_process_written_superblock(
2263                 struct btrfsic_state *state,
2264                 struct btrfsic_block *const superblock,
2265                 struct btrfs_super_block *const super_hdr)
2266 {
2267         int pass;
2268 
2269         superblock->generation = btrfs_super_generation(super_hdr);
2270         if (!(superblock->generation > state->max_superblock_generation ||
2271               0 == state->max_superblock_generation)) {
2272                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2273                         printk(KERN_INFO
2274                                "btrfsic: superblock @%llu (%s/%llu/%d)"
2275                                " with old gen %llu <= %llu\n",
2276                                superblock->logical_bytenr,
2277                                superblock->dev_state->name,
2278                                superblock->dev_bytenr, superblock->mirror_num,
2279                                btrfs_super_generation(super_hdr),
2280                                state->max_superblock_generation);
2281         } else {
2282                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2283                         printk(KERN_INFO
2284                                "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2285                                " with new gen %llu > %llu\n",
2286                                superblock->logical_bytenr,
2287                                superblock->dev_state->name,
2288                                superblock->dev_bytenr, superblock->mirror_num,
2289                                btrfs_super_generation(super_hdr),
2290                                state->max_superblock_generation);
2291 
2292                 state->max_superblock_generation =
2293                     btrfs_super_generation(super_hdr);
2294                 state->latest_superblock = superblock;
2295         }
2296 
2297         for (pass = 0; pass < 3; pass++) {
2298                 int ret;
2299                 u64 next_bytenr;
2300                 struct btrfsic_block *next_block;
2301                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2302                 struct btrfsic_block_link *l;
2303                 int num_copies;
2304                 int mirror_num;
2305                 const char *additional_string = NULL;
2306                 struct btrfs_disk_key tmp_disk_key = {0};
2307 
2308                 btrfs_set_disk_key_objectid(&tmp_disk_key,
2309                                             BTRFS_ROOT_ITEM_KEY);
2310                 btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2311 
2312                 switch (pass) {
2313                 case 0:
2314                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2315                                                     BTRFS_ROOT_TREE_OBJECTID);
2316                         additional_string = "root ";
2317                         next_bytenr = btrfs_super_root(super_hdr);
2318                         if (state->print_mask &
2319                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2320                                 printk(KERN_INFO "root@%llu\n", next_bytenr);
2321                         break;
2322                 case 1:
2323                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2324                                                     BTRFS_CHUNK_TREE_OBJECTID);
2325                         additional_string = "chunk ";
2326                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2327                         if (state->print_mask &
2328                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2329                                 printk(KERN_INFO "chunk@%llu\n", next_bytenr);
2330                         break;
2331                 case 2:
2332                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2333                                                     BTRFS_TREE_LOG_OBJECTID);
2334                         additional_string = "log ";
2335                         next_bytenr = btrfs_super_log_root(super_hdr);
2336                         if (0 == next_bytenr)
2337                                 continue;
2338                         if (state->print_mask &
2339                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2340                                 printk(KERN_INFO "log@%llu\n", next_bytenr);
2341                         break;
2342                 }
2343 
2344                 num_copies =
2345                     btrfs_num_copies(state->root->fs_info,
2346                                      next_bytenr, BTRFS_SUPER_INFO_SIZE);
2347                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2348                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2349                                next_bytenr, num_copies);
2350                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2351                         int was_created;
2352 
2353                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2354                                 printk(KERN_INFO
2355                                        "btrfsic_process_written_superblock("
2356                                        "mirror_num=%d)\n", mirror_num);
2357                         ret = btrfsic_map_block(state, next_bytenr,
2358                                                 BTRFS_SUPER_INFO_SIZE,
2359                                                 &tmp_next_block_ctx,
2360                                                 mirror_num);
2361                         if (ret) {
2362                                 printk(KERN_INFO
2363                                        "btrfsic: btrfsic_map_block(@%llu,"
2364                                        " mirror=%d) failed!\n",
2365                                        next_bytenr, mirror_num);
2366                                 return -1;
2367                         }
2368 
2369                         next_block = btrfsic_block_lookup_or_add(
2370                                         state,
2371                                         &tmp_next_block_ctx,
2372                                         additional_string,
2373                                         1, 0, 1,
2374                                         mirror_num,
2375                                         &was_created);
2376                         if (NULL == next_block) {
2377                                 printk(KERN_INFO
2378                                        "btrfsic: error, kmalloc failed!\n");
2379                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2380                                 return -1;
2381                         }
2382 
2383                         next_block->disk_key = tmp_disk_key;
2384                         if (was_created)
2385                                 next_block->generation =
2386                                     BTRFSIC_GENERATION_UNKNOWN;
2387                         l = btrfsic_block_link_lookup_or_add(
2388                                         state,
2389                                         &tmp_next_block_ctx,
2390                                         next_block,
2391                                         superblock,
2392                                         BTRFSIC_GENERATION_UNKNOWN);
2393                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2394                         if (NULL == l)
2395                                 return -1;
2396                 }
2397         }
2398 
2399         if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2400                 btrfsic_dump_tree(state);
2401 
2402         return 0;
2403 }
2404 
2405 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2406                                         struct btrfsic_block *const block,
2407                                         int recursion_level)
2408 {
2409         const struct btrfsic_block_link *l;
2410         int ret = 0;
2411 
2412         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2413                 /*
2414                  * Note that this situation can happen and does not
2415                  * indicate an error in regular cases. It happens
2416                  * when disk blocks are freed and later reused.
2417                  * The check-integrity module is not aware of any
2418                  * block free operations, it just recognizes block
2419                  * write operations. Therefore it keeps the linkage
2420                  * information for a block until a block is
2421                  * rewritten. This can temporarily cause incorrect
2422                  * and even circular linkage informations. This
2423                  * causes no harm unless such blocks are referenced
2424                  * by the most recent super block.
2425                  */
2426                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2427                         printk(KERN_INFO
2428                                "btrfsic: abort cyclic linkage (case 1).\n");
2429 
2430                 return ret;
2431         }
2432 
2433         /*
2434          * This algorithm is recursive because the amount of used stack
2435          * space is very small and the max recursion depth is limited.
2436          */
2437         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2438                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2439                         printk(KERN_INFO
2440                                "rl=%d, %c @%llu (%s/%llu/%d)"
2441                                " %u* refers to %c @%llu (%s/%llu/%d)\n",
2442                                recursion_level,
2443                                btrfsic_get_block_type(state, block),
2444                                block->logical_bytenr, block->dev_state->name,
2445                                block->dev_bytenr, block->mirror_num,
2446                                l->ref_cnt,
2447                                btrfsic_get_block_type(state, l->block_ref_to),
2448                                l->block_ref_to->logical_bytenr,
2449                                l->block_ref_to->dev_state->name,
2450                                l->block_ref_to->dev_bytenr,
2451                                l->block_ref_to->mirror_num);
2452                 if (l->block_ref_to->never_written) {
2453                         printk(KERN_INFO "btrfs: attempt to write superblock"
2454                                " which references block %c @%llu (%s/%llu/%d)"
2455                                " which is never written!\n",
2456                                btrfsic_get_block_type(state, l->block_ref_to),
2457                                l->block_ref_to->logical_bytenr,
2458                                l->block_ref_to->dev_state->name,
2459                                l->block_ref_to->dev_bytenr,
2460                                l->block_ref_to->mirror_num);
2461                         ret = -1;
2462                 } else if (!l->block_ref_to->is_iodone) {
2463                         printk(KERN_INFO "btrfs: attempt to write superblock"
2464                                " which references block %c @%llu (%s/%llu/%d)"
2465                                " which is not yet iodone!\n",
2466                                btrfsic_get_block_type(state, l->block_ref_to),
2467                                l->block_ref_to->logical_bytenr,
2468                                l->block_ref_to->dev_state->name,
2469                                l->block_ref_to->dev_bytenr,
2470                                l->block_ref_to->mirror_num);
2471                         ret = -1;
2472                 } else if (l->block_ref_to->iodone_w_error) {
2473                         printk(KERN_INFO "btrfs: attempt to write superblock"
2474                                " which references block %c @%llu (%s/%llu/%d)"
2475                                " which has write error!\n",
2476                                btrfsic_get_block_type(state, l->block_ref_to),
2477                                l->block_ref_to->logical_bytenr,
2478                                l->block_ref_to->dev_state->name,
2479                                l->block_ref_to->dev_bytenr,
2480                                l->block_ref_to->mirror_num);
2481                         ret = -1;
2482                 } else if (l->parent_generation !=
2483                            l->block_ref_to->generation &&
2484                            BTRFSIC_GENERATION_UNKNOWN !=
2485                            l->parent_generation &&
2486                            BTRFSIC_GENERATION_UNKNOWN !=
2487                            l->block_ref_to->generation) {
2488                         printk(KERN_INFO "btrfs: attempt to write superblock"
2489                                " which references block %c @%llu (%s/%llu/%d)"
2490                                " with generation %llu !="
2491                                " parent generation %llu!\n",
2492                                btrfsic_get_block_type(state, l->block_ref_to),
2493                                l->block_ref_to->logical_bytenr,
2494                                l->block_ref_to->dev_state->name,
2495                                l->block_ref_to->dev_bytenr,
2496                                l->block_ref_to->mirror_num,
2497                                l->block_ref_to->generation,
2498                                l->parent_generation);
2499                         ret = -1;
2500                 } else if (l->block_ref_to->flush_gen >
2501                            l->block_ref_to->dev_state->last_flush_gen) {
2502                         printk(KERN_INFO "btrfs: attempt to write superblock"
2503                                " which references block %c @%llu (%s/%llu/%d)"
2504                                " which is not flushed out of disk's write cache"
2505                                " (block flush_gen=%llu,"
2506                                " dev->flush_gen=%llu)!\n",
2507                                btrfsic_get_block_type(state, l->block_ref_to),
2508                                l->block_ref_to->logical_bytenr,
2509                                l->block_ref_to->dev_state->name,
2510                                l->block_ref_to->dev_bytenr,
2511                                l->block_ref_to->mirror_num, block->flush_gen,
2512                                l->block_ref_to->dev_state->last_flush_gen);
2513                         ret = -1;
2514                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2515                                                               l->block_ref_to,
2516                                                               recursion_level +
2517                                                               1)) {
2518                         ret = -1;
2519                 }
2520         }
2521 
2522         return ret;
2523 }
2524 
2525 static int btrfsic_is_block_ref_by_superblock(
2526                 const struct btrfsic_state *state,
2527                 const struct btrfsic_block *block,
2528                 int recursion_level)
2529 {
2530         const struct btrfsic_block_link *l;
2531 
2532         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2533                 /* refer to comment at "abort cyclic linkage (case 1)" */
2534                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2535                         printk(KERN_INFO
2536                                "btrfsic: abort cyclic linkage (case 2).\n");
2537 
2538                 return 0;
2539         }
2540 
2541         /*
2542          * This algorithm is recursive because the amount of used stack space
2543          * is very small and the max recursion depth is limited.
2544          */
2545         list_for_each_entry(l, &block->ref_from_list, node_ref_from) {
2546                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2547                         printk(KERN_INFO
2548                                "rl=%d, %c @%llu (%s/%llu/%d)"
2549                                " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2550                                recursion_level,
2551                                btrfsic_get_block_type(state, block),
2552                                block->logical_bytenr, block->dev_state->name,
2553                                block->dev_bytenr, block->mirror_num,
2554                                l->ref_cnt,
2555                                btrfsic_get_block_type(state, l->block_ref_from),
2556                                l->block_ref_from->logical_bytenr,
2557                                l->block_ref_from->dev_state->name,
2558                                l->block_ref_from->dev_bytenr,
2559                                l->block_ref_from->mirror_num);
2560                 if (l->block_ref_from->is_superblock &&
2561                     state->latest_superblock->dev_bytenr ==
2562                     l->block_ref_from->dev_bytenr &&
2563                     state->latest_superblock->dev_state->bdev ==
2564                     l->block_ref_from->dev_state->bdev)
2565                         return 1;
2566                 else if (btrfsic_is_block_ref_by_superblock(state,
2567                                                             l->block_ref_from,
2568                                                             recursion_level +
2569                                                             1))
2570                         return 1;
2571         }
2572 
2573         return 0;
2574 }
2575 
2576 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2577                                    const struct btrfsic_block_link *l)
2578 {
2579         printk(KERN_INFO
2580                "Add %u* link from %c @%llu (%s/%llu/%d)"
2581                " to %c @%llu (%s/%llu/%d).\n",
2582                l->ref_cnt,
2583                btrfsic_get_block_type(state, l->block_ref_from),
2584                l->block_ref_from->logical_bytenr,
2585                l->block_ref_from->dev_state->name,
2586                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2587                btrfsic_get_block_type(state, l->block_ref_to),
2588                l->block_ref_to->logical_bytenr,
2589                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2590                l->block_ref_to->mirror_num);
2591 }
2592 
2593 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2594                                    const struct btrfsic_block_link *l)
2595 {
2596         printk(KERN_INFO
2597                "Rem %u* link from %c @%llu (%s/%llu/%d)"
2598                " to %c @%llu (%s/%llu/%d).\n",
2599                l->ref_cnt,
2600                btrfsic_get_block_type(state, l->block_ref_from),
2601                l->block_ref_from->logical_bytenr,
2602                l->block_ref_from->dev_state->name,
2603                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2604                btrfsic_get_block_type(state, l->block_ref_to),
2605                l->block_ref_to->logical_bytenr,
2606                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2607                l->block_ref_to->mirror_num);
2608 }
2609 
2610 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2611                                    const struct btrfsic_block *block)
2612 {
2613         if (block->is_superblock &&
2614             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2615             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2616                 return 'S';
2617         else if (block->is_superblock)
2618                 return 's';
2619         else if (block->is_metadata)
2620                 return 'M';
2621         else
2622                 return 'D';
2623 }
2624 
2625 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2626 {
2627         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2628 }
2629 
2630 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2631                                   const struct btrfsic_block *block,
2632                                   int indent_level)
2633 {
2634         const struct btrfsic_block_link *l;
2635         int indent_add;
2636         static char buf[80];
2637         int cursor_position;
2638 
2639         /*
2640          * Should better fill an on-stack buffer with a complete line and
2641          * dump it at once when it is time to print a newline character.
2642          */
2643 
2644         /*
2645          * This algorithm is recursive because the amount of used stack space
2646          * is very small and the max recursion depth is limited.
2647          */
2648         indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2649                              btrfsic_get_block_type(state, block),
2650                              block->logical_bytenr, block->dev_state->name,
2651                              block->dev_bytenr, block->mirror_num);
2652         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2653                 printk("[...]\n");
2654                 return;
2655         }
2656         printk(buf);
2657         indent_level += indent_add;
2658         if (list_empty(&block->ref_to_list)) {
2659                 printk("\n");
2660                 return;
2661         }
2662         if (block->mirror_num > 1 &&
2663             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2664                 printk(" [...]\n");
2665                 return;
2666         }
2667 
2668         cursor_position = indent_level;
2669         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2670                 while (cursor_position < indent_level) {
2671                         printk(" ");
2672                         cursor_position++;
2673                 }
2674                 if (l->ref_cnt > 1)
2675                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2676                 else
2677                         indent_add = sprintf(buf, " --> ");
2678                 if (indent_level + indent_add >
2679                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2680                         printk("[...]\n");
2681                         cursor_position = 0;
2682                         continue;
2683                 }
2684 
2685                 printk(buf);
2686 
2687                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2688                                       indent_level + indent_add);
2689                 cursor_position = 0;
2690         }
2691 }
2692 
2693 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2694                 struct btrfsic_state *state,
2695                 struct btrfsic_block_data_ctx *next_block_ctx,
2696                 struct btrfsic_block *next_block,
2697                 struct btrfsic_block *from_block,
2698                 u64 parent_generation)
2699 {
2700         struct btrfsic_block_link *l;
2701 
2702         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2703                                                 next_block_ctx->dev_bytenr,
2704                                                 from_block->dev_state->bdev,
2705                                                 from_block->dev_bytenr,
2706                                                 &state->block_link_hashtable);
2707         if (NULL == l) {
2708                 l = btrfsic_block_link_alloc();
2709                 if (NULL == l) {
2710                         printk(KERN_INFO
2711                                "btrfsic: error, kmalloc" " failed!\n");
2712                         return NULL;
2713                 }
2714 
2715                 l->block_ref_to = next_block;
2716                 l->block_ref_from = from_block;
2717                 l->ref_cnt = 1;
2718                 l->parent_generation = parent_generation;
2719 
2720                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2721                         btrfsic_print_add_link(state, l);
2722 
2723                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2724                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2725 
2726                 btrfsic_block_link_hashtable_add(l,
2727                                                  &state->block_link_hashtable);
2728         } else {
2729                 l->ref_cnt++;
2730                 l->parent_generation = parent_generation;
2731                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2732                         btrfsic_print_add_link(state, l);
2733         }
2734 
2735         return l;
2736 }
2737 
2738 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2739                 struct btrfsic_state *state,
2740                 struct btrfsic_block_data_ctx *block_ctx,
2741                 const char *additional_string,
2742                 int is_metadata,
2743                 int is_iodone,
2744                 int never_written,
2745                 int mirror_num,
2746                 int *was_created)
2747 {
2748         struct btrfsic_block *block;
2749 
2750         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2751                                                block_ctx->dev_bytenr,
2752                                                &state->block_hashtable);
2753         if (NULL == block) {
2754                 struct btrfsic_dev_state *dev_state;
2755 
2756                 block = btrfsic_block_alloc();
2757                 if (NULL == block) {
2758                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2759                         return NULL;
2760                 }
2761                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2762                 if (NULL == dev_state) {
2763                         printk(KERN_INFO
2764                                "btrfsic: error, lookup dev_state failed!\n");
2765                         btrfsic_block_free(block);
2766                         return NULL;
2767                 }
2768                 block->dev_state = dev_state;
2769                 block->dev_bytenr = block_ctx->dev_bytenr;
2770                 block->logical_bytenr = block_ctx->start;
2771                 block->is_metadata = is_metadata;
2772                 block->is_iodone = is_iodone;
2773                 block->never_written = never_written;
2774                 block->mirror_num = mirror_num;
2775                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2776                         printk(KERN_INFO
2777                                "New %s%c-block @%llu (%s/%llu/%d)\n",
2778                                additional_string,
2779                                btrfsic_get_block_type(state, block),
2780                                block->logical_bytenr, dev_state->name,
2781                                block->dev_bytenr, mirror_num);
2782                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2783                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2784                 if (NULL != was_created)
2785                         *was_created = 1;
2786         } else {
2787                 if (NULL != was_created)
2788                         *was_created = 0;
2789         }
2790 
2791         return block;
2792 }
2793 
2794 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2795                                            u64 bytenr,
2796                                            struct btrfsic_dev_state *dev_state,
2797                                            u64 dev_bytenr)
2798 {
2799         int num_copies;
2800         int mirror_num;
2801         int ret;
2802         struct btrfsic_block_data_ctx block_ctx;
2803         int match = 0;
2804 
2805         num_copies = btrfs_num_copies(state->root->fs_info,
2806                                       bytenr, state->metablock_size);
2807 
2808         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2809                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2810                                         &block_ctx, mirror_num);
2811                 if (ret) {
2812                         printk(KERN_INFO "btrfsic:"
2813                                " btrfsic_map_block(logical @%llu,"
2814                                " mirror %d) failed!\n",
2815                                bytenr, mirror_num);
2816                         continue;
2817                 }
2818 
2819                 if (dev_state->bdev == block_ctx.dev->bdev &&
2820                     dev_bytenr == block_ctx.dev_bytenr) {
2821                         match++;
2822                         btrfsic_release_block_ctx(&block_ctx);
2823                         break;
2824                 }
2825                 btrfsic_release_block_ctx(&block_ctx);
2826         }
2827 
2828         if (WARN_ON(!match)) {
2829                 printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2830                        " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2831                        " phys_bytenr=%llu)!\n",
2832                        bytenr, dev_state->name, dev_bytenr);
2833                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2834                         ret = btrfsic_map_block(state, bytenr,
2835                                                 state->metablock_size,
2836                                                 &block_ctx, mirror_num);
2837                         if (ret)
2838                                 continue;
2839 
2840                         printk(KERN_INFO "Read logical bytenr @%llu maps to"
2841                                " (%s/%llu/%d)\n",
2842                                bytenr, block_ctx.dev->name,
2843                                block_ctx.dev_bytenr, mirror_num);
2844                 }
2845         }
2846 }
2847 
2848 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2849                 struct block_device *bdev)
2850 {
2851         struct btrfsic_dev_state *ds;
2852 
2853         ds = btrfsic_dev_state_hashtable_lookup(bdev,
2854                                                 &btrfsic_dev_state_hashtable);
2855         return ds;
2856 }
2857 
2858 int btrfsic_submit_bh(int rw, struct buffer_head *bh)
2859 {
2860         struct btrfsic_dev_state *dev_state;
2861 
2862         if (!btrfsic_is_initialized)
2863                 return submit_bh(rw, bh);
2864 
2865         mutex_lock(&btrfsic_mutex);
2866         /* since btrfsic_submit_bh() might also be called before
2867          * btrfsic_mount(), this might return NULL */
2868         dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
2869 
2870         /* Only called to write the superblock (incl. FLUSH/FUA) */
2871         if (NULL != dev_state &&
2872             (rw & WRITE) && bh->b_size > 0) {
2873                 u64 dev_bytenr;
2874 
2875                 dev_bytenr = 4096 * bh->b_blocknr;
2876                 if (dev_state->state->print_mask &
2877                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2878                         printk(KERN_INFO
2879                                "submit_bh(rw=0x%x, blocknr=%llu (bytenr %llu),"
2880                                " size=%zu, data=%p, bdev=%p)\n",
2881                                rw, (unsigned long long)bh->b_blocknr,
2882                                dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2883                 btrfsic_process_written_block(dev_state, dev_bytenr,
2884                                               &bh->b_data, 1, NULL,
2885                                               NULL, bh, rw);
2886         } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
2887                 if (dev_state->state->print_mask &
2888                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2889                         printk(KERN_INFO
2890                                "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
2891                                rw, bh->b_bdev);
2892                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2893                         if ((dev_state->state->print_mask &
2894                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2895                               BTRFSIC_PRINT_MASK_VERBOSE)))
2896                                 printk(KERN_INFO
2897                                        "btrfsic_submit_bh(%s) with FLUSH"
2898                                        " but dummy block already in use"
2899                                        " (ignored)!\n",
2900                                        dev_state->name);
2901                 } else {
2902                         struct btrfsic_block *const block =
2903                                 &dev_state->dummy_block_for_bio_bh_flush;
2904 
2905                         block->is_iodone = 0;
2906                         block->never_written = 0;
2907                         block->iodone_w_error = 0;
2908                         block->flush_gen = dev_state->last_flush_gen + 1;
2909                         block->submit_bio_bh_rw = rw;
2910                         block->orig_bio_bh_private = bh->b_private;
2911                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2912                         block->next_in_same_bio = NULL;
2913                         bh->b_private = block;
2914                         bh->b_end_io = btrfsic_bh_end_io;
2915                 }
2916         }
2917         mutex_unlock(&btrfsic_mutex);
2918         return submit_bh(rw, bh);
2919 }
2920 
2921 static void __btrfsic_submit_bio(int rw, struct bio *bio)
2922 {
2923         struct btrfsic_dev_state *dev_state;
2924 
2925         if (!btrfsic_is_initialized)
2926                 return;
2927 
2928         mutex_lock(&btrfsic_mutex);
2929         /* since btrfsic_submit_bio() is also called before
2930          * btrfsic_mount(), this might return NULL */
2931         dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
2932         if (NULL != dev_state &&
2933             (rw & WRITE) && NULL != bio->bi_io_vec) {
2934                 unsigned int i;
2935                 u64 dev_bytenr;
2936                 u64 cur_bytenr;
2937                 int bio_is_patched;
2938                 char **mapped_datav;
2939 
2940                 dev_bytenr = 512 * bio->bi_iter.bi_sector;
2941                 bio_is_patched = 0;
2942                 if (dev_state->state->print_mask &
2943                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2944                         printk(KERN_INFO
2945                                "submit_bio(rw=0x%x, bi_vcnt=%u,"
2946                                " bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
2947                                rw, bio->bi_vcnt,
2948                                (unsigned long long)bio->bi_iter.bi_sector,
2949                                dev_bytenr, bio->bi_bdev);
2950 
2951                 mapped_datav = kmalloc_array(bio->bi_vcnt,
2952                                              sizeof(*mapped_datav), GFP_NOFS);
2953                 if (!mapped_datav)
2954                         goto leave;
2955                 cur_bytenr = dev_bytenr;
2956                 for (i = 0; i < bio->bi_vcnt; i++) {
2957                         BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_SIZE);
2958                         mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
2959                         if (!mapped_datav[i]) {
2960                                 while (i > 0) {
2961                                         i--;
2962                                         kunmap(bio->bi_io_vec[i].bv_page);
2963                                 }
2964                                 kfree(mapped_datav);
2965                                 goto leave;
2966                         }
2967                         if (dev_state->state->print_mask &
2968                             BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
2969                                 printk(KERN_INFO
2970                                        "#%u: bytenr=%llu, len=%u, offset=%u\n",
2971                                        i, cur_bytenr, bio->bi_io_vec[i].bv_len,
2972                                        bio->bi_io_vec[i].bv_offset);
2973                         cur_bytenr += bio->bi_io_vec[i].bv_len;
2974                 }
2975                 btrfsic_process_written_block(dev_state, dev_bytenr,
2976                                               mapped_datav, bio->bi_vcnt,
2977                                               bio, &bio_is_patched,
2978                                               NULL, rw);
2979                 while (i > 0) {
2980                         i--;
2981                         kunmap(bio->bi_io_vec[i].bv_page);
2982                 }
2983                 kfree(mapped_datav);
2984         } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
2985                 if (dev_state->state->print_mask &
2986                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2987                         printk(KERN_INFO
2988                                "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
2989                                rw, bio->bi_bdev);
2990                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2991                         if ((dev_state->state->print_mask &
2992                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2993                               BTRFSIC_PRINT_MASK_VERBOSE)))
2994                                 printk(KERN_INFO
2995                                        "btrfsic_submit_bio(%s) with FLUSH"
2996                                        " but dummy block already in use"
2997                                        " (ignored)!\n",
2998                                        dev_state->name);
2999                 } else {
3000                         struct btrfsic_block *const block =
3001                                 &dev_state->dummy_block_for_bio_bh_flush;
3002 
3003                         block->is_iodone = 0;
3004                         block->never_written = 0;
3005                         block->iodone_w_error = 0;
3006                         block->flush_gen = dev_state->last_flush_gen + 1;
3007                         block->submit_bio_bh_rw = rw;
3008                         block->orig_bio_bh_private = bio->bi_private;
3009                         block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3010                         block->next_in_same_bio = NULL;
3011                         bio->bi_private = block;
3012                         bio->bi_end_io = btrfsic_bio_end_io;
3013                 }
3014         }
3015 leave:
3016         mutex_unlock(&btrfsic_mutex);
3017 }
3018 
3019 void btrfsic_submit_bio(int rw, struct bio *bio)
3020 {
3021         __btrfsic_submit_bio(rw, bio);
3022         submit_bio(rw, bio);
3023 }
3024 
3025 int btrfsic_submit_bio_wait(int rw, struct bio *bio)
3026 {
3027         __btrfsic_submit_bio(rw, bio);
3028         return submit_bio_wait(rw, bio);
3029 }
3030 
3031 int btrfsic_mount(struct btrfs_root *root,
3032                   struct btrfs_fs_devices *fs_devices,
3033                   int including_extent_data, u32 print_mask)
3034 {
3035         int ret;
3036         struct btrfsic_state *state;
3037         struct list_head *dev_head = &fs_devices->devices;
3038         struct btrfs_device *device;
3039 
3040         if (root->nodesize & ((u64)PAGE_SIZE - 1)) {
3041                 printk(KERN_INFO
3042                        "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_SIZE %ld!\n",
3043                        root->nodesize, PAGE_SIZE);
3044                 return -1;
3045         }
3046         if (root->sectorsize & ((u64)PAGE_SIZE - 1)) {
3047                 printk(KERN_INFO
3048                        "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_SIZE %ld!\n",
3049                        root->sectorsize, PAGE_SIZE);
3050                 return -1;
3051         }
3052         state = kzalloc(sizeof(*state), GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
3053         if (!state) {
3054                 state = vzalloc(sizeof(*state));
3055                 if (!state) {
3056                         printk(KERN_INFO "btrfs check-integrity: vzalloc() failed!\n");
3057                         return -1;
3058                 }
3059         }
3060 
3061         if (!btrfsic_is_initialized) {
3062                 mutex_init(&btrfsic_mutex);
3063                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3064                 btrfsic_is_initialized = 1;
3065         }
3066         mutex_lock(&btrfsic_mutex);
3067         state->root = root;
3068         state->print_mask = print_mask;
3069         state->include_extent_data = including_extent_data;
3070         state->csum_size = 0;
3071         state->metablock_size = root->nodesize;
3072         state->datablock_size = root->sectorsize;
3073         INIT_LIST_HEAD(&state->all_blocks_list);
3074         btrfsic_block_hashtable_init(&state->block_hashtable);
3075         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3076         state->max_superblock_generation = 0;
3077         state->latest_superblock = NULL;
3078 
3079         list_for_each_entry(device, dev_head, dev_list) {
3080                 struct btrfsic_dev_state *ds;
3081                 const char *p;
3082 
3083                 if (!device->bdev || !device->name)
3084                         continue;
3085 
3086                 ds = btrfsic_dev_state_alloc();
3087                 if (NULL == ds) {
3088                         printk(KERN_INFO
3089                                "btrfs check-integrity: kmalloc() failed!\n");
3090                         mutex_unlock(&btrfsic_mutex);
3091                         return -1;
3092                 }
3093                 ds->bdev = device->bdev;
3094                 ds->state = state;
3095                 bdevname(ds->bdev, ds->name);
3096                 ds->name[BDEVNAME_SIZE - 1] = '\0';
3097                 p = kbasename(ds->name);
3098                 strlcpy(ds->name, p, sizeof(ds->name));
3099                 btrfsic_dev_state_hashtable_add(ds,
3100                                                 &btrfsic_dev_state_hashtable);
3101         }
3102 
3103         ret = btrfsic_process_superblock(state, fs_devices);
3104         if (0 != ret) {
3105                 mutex_unlock(&btrfsic_mutex);
3106                 btrfsic_unmount(root, fs_devices);
3107                 return ret;
3108         }
3109 
3110         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3111                 btrfsic_dump_database(state);
3112         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3113                 btrfsic_dump_tree(state);
3114 
3115         mutex_unlock(&btrfsic_mutex);
3116         return 0;
3117 }
3118 
3119 void btrfsic_unmount(struct btrfs_root *root,
3120                      struct btrfs_fs_devices *fs_devices)
3121 {
3122         struct btrfsic_block *b_all, *tmp_all;
3123         struct btrfsic_state *state;
3124         struct list_head *dev_head = &fs_devices->devices;
3125         struct btrfs_device *device;
3126 
3127         if (!btrfsic_is_initialized)
3128                 return;
3129 
3130         mutex_lock(&btrfsic_mutex);
3131 
3132         state = NULL;
3133         list_for_each_entry(device, dev_head, dev_list) {
3134                 struct btrfsic_dev_state *ds;
3135 
3136                 if (!device->bdev || !device->name)
3137                         continue;
3138 
3139                 ds = btrfsic_dev_state_hashtable_lookup(
3140                                 device->bdev,
3141                                 &btrfsic_dev_state_hashtable);
3142                 if (NULL != ds) {
3143                         state = ds->state;
3144                         btrfsic_dev_state_hashtable_remove(ds);
3145                         btrfsic_dev_state_free(ds);
3146                 }
3147         }
3148 
3149         if (NULL == state) {
3150                 printk(KERN_INFO
3151                        "btrfsic: error, cannot find state information"
3152                        " on umount!\n");
3153                 mutex_unlock(&btrfsic_mutex);
3154                 return;
3155         }
3156 
3157         /*
3158          * Don't care about keeping the lists' state up to date,
3159          * just free all memory that was allocated dynamically.
3160          * Free the blocks and the block_links.
3161          */
3162         list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
3163                                  all_blocks_node) {
3164                 struct btrfsic_block_link *l, *tmp;
3165 
3166                 list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
3167                                          node_ref_to) {
3168                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3169                                 btrfsic_print_rem_link(state, l);
3170 
3171                         l->ref_cnt--;
3172                         if (0 == l->ref_cnt)
3173                                 btrfsic_block_link_free(l);
3174                 }
3175 
3176                 if (b_all->is_iodone || b_all->never_written)
3177                         btrfsic_block_free(b_all);
3178                 else
3179                         printk(KERN_INFO "btrfs: attempt to free %c-block"
3180                                " @%llu (%s/%llu/%d) on umount which is"
3181                                " not yet iodone!\n",
3182                                btrfsic_get_block_type(state, b_all),
3183                                b_all->logical_bytenr, b_all->dev_state->name,
3184                                b_all->dev_bytenr, b_all->mirror_num);
3185         }
3186 
3187         mutex_unlock(&btrfsic_mutex);
3188 
3189         kvfree(state);
3190 }
3191 

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