xref: /openbmc/linux/fs/btrfs/check-integrity.c (revision ee89bd6b)
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 
82 #include <linux/sched.h>
83 #include <linux/slab.h>
84 #include <linux/buffer_head.h>
85 #include <linux/mutex.h>
86 #include <linux/crc32c.h>
87 #include <linux/genhd.h>
88 #include <linux/blkdev.h>
89 #include "ctree.h"
90 #include "disk-io.h"
91 #include "transaction.h"
92 #include "extent_io.h"
93 #include "volumes.h"
94 #include "print-tree.h"
95 #include "locking.h"
96 #include "check-integrity.h"
97 #include "rcu-string.h"
98 
99 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
100 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
101 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
102 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
103 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
104 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
105 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
106 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)	/* in characters,
107 							 * excluding " [...]" */
108 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
109 
110 /*
111  * The definition of the bitmask fields for the print_mask.
112  * They are specified with the mount option check_integrity_print_mask.
113  */
114 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE			0x00000001
115 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION		0x00000002
116 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE			0x00000004
117 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE			0x00000008
118 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH			0x00000010
119 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH			0x00000020
120 #define BTRFSIC_PRINT_MASK_VERBOSE				0x00000040
121 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE				0x00000080
122 #define BTRFSIC_PRINT_MASK_INITIAL_TREE				0x00000100
123 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES			0x00000200
124 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE			0x00000400
125 #define BTRFSIC_PRINT_MASK_NUM_COPIES				0x00000800
126 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS		0x00001000
127 
128 struct btrfsic_dev_state;
129 struct btrfsic_state;
130 
131 struct btrfsic_block {
132 	u32 magic_num;		/* only used for debug purposes */
133 	unsigned int is_metadata:1;	/* if it is meta-data, not data-data */
134 	unsigned int is_superblock:1;	/* if it is one of the superblocks */
135 	unsigned int is_iodone:1;	/* if is done by lower subsystem */
136 	unsigned int iodone_w_error:1;	/* error was indicated to endio */
137 	unsigned int never_written:1;	/* block was added because it was
138 					 * referenced, not because it was
139 					 * written */
140 	unsigned int mirror_num;	/* large enough to hold
141 					 * BTRFS_SUPER_MIRROR_MAX */
142 	struct btrfsic_dev_state *dev_state;
143 	u64 dev_bytenr;		/* key, physical byte num on disk */
144 	u64 logical_bytenr;	/* logical byte num on disk */
145 	u64 generation;
146 	struct btrfs_disk_key disk_key;	/* extra info to print in case of
147 					 * issues, will not always be correct */
148 	struct list_head collision_resolving_node;	/* list node */
149 	struct list_head all_blocks_node;	/* list node */
150 
151 	/* the following two lists contain block_link items */
152 	struct list_head ref_to_list;	/* list */
153 	struct list_head ref_from_list;	/* list */
154 	struct btrfsic_block *next_in_same_bio;
155 	void *orig_bio_bh_private;
156 	union {
157 		bio_end_io_t *bio;
158 		bh_end_io_t *bh;
159 	} orig_bio_bh_end_io;
160 	int submit_bio_bh_rw;
161 	u64 flush_gen; /* only valid if !never_written */
162 };
163 
164 /*
165  * Elements of this type are allocated dynamically and required because
166  * each block object can refer to and can be ref from multiple blocks.
167  * The key to lookup them in the hashtable is the dev_bytenr of
168  * the block ref to plus the one from the block refered from.
169  * The fact that they are searchable via a hashtable and that a
170  * ref_cnt is maintained is not required for the btrfs integrity
171  * check algorithm itself, it is only used to make the output more
172  * beautiful in case that an error is detected (an error is defined
173  * as a write operation to a block while that block is still referenced).
174  */
175 struct btrfsic_block_link {
176 	u32 magic_num;		/* only used for debug purposes */
177 	u32 ref_cnt;
178 	struct list_head node_ref_to;	/* list node */
179 	struct list_head node_ref_from;	/* list node */
180 	struct list_head collision_resolving_node;	/* list node */
181 	struct btrfsic_block *block_ref_to;
182 	struct btrfsic_block *block_ref_from;
183 	u64 parent_generation;
184 };
185 
186 struct btrfsic_dev_state {
187 	u32 magic_num;		/* only used for debug purposes */
188 	struct block_device *bdev;
189 	struct btrfsic_state *state;
190 	struct list_head collision_resolving_node;	/* list node */
191 	struct btrfsic_block dummy_block_for_bio_bh_flush;
192 	u64 last_flush_gen;
193 	char name[BDEVNAME_SIZE];
194 };
195 
196 struct btrfsic_block_hashtable {
197 	struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
198 };
199 
200 struct btrfsic_block_link_hashtable {
201 	struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
202 };
203 
204 struct btrfsic_dev_state_hashtable {
205 	struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
206 };
207 
208 struct btrfsic_block_data_ctx {
209 	u64 start;		/* virtual bytenr */
210 	u64 dev_bytenr;		/* physical bytenr on device */
211 	u32 len;
212 	struct btrfsic_dev_state *dev;
213 	char **datav;
214 	struct page **pagev;
215 	void *mem_to_free;
216 };
217 
218 /* This structure is used to implement recursion without occupying
219  * any stack space, refer to btrfsic_process_metablock() */
220 struct btrfsic_stack_frame {
221 	u32 magic;
222 	u32 nr;
223 	int error;
224 	int i;
225 	int limit_nesting;
226 	int num_copies;
227 	int mirror_num;
228 	struct btrfsic_block *block;
229 	struct btrfsic_block_data_ctx *block_ctx;
230 	struct btrfsic_block *next_block;
231 	struct btrfsic_block_data_ctx next_block_ctx;
232 	struct btrfs_header *hdr;
233 	struct btrfsic_stack_frame *prev;
234 };
235 
236 /* Some state per mounted filesystem */
237 struct btrfsic_state {
238 	u32 print_mask;
239 	int include_extent_data;
240 	int csum_size;
241 	struct list_head all_blocks_list;
242 	struct btrfsic_block_hashtable block_hashtable;
243 	struct btrfsic_block_link_hashtable block_link_hashtable;
244 	struct btrfs_root *root;
245 	u64 max_superblock_generation;
246 	struct btrfsic_block *latest_superblock;
247 	u32 metablock_size;
248 	u32 datablock_size;
249 };
250 
251 static void btrfsic_block_init(struct btrfsic_block *b);
252 static struct btrfsic_block *btrfsic_block_alloc(void);
253 static void btrfsic_block_free(struct btrfsic_block *b);
254 static void btrfsic_block_link_init(struct btrfsic_block_link *n);
255 static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
256 static void btrfsic_block_link_free(struct btrfsic_block_link *n);
257 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
258 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
259 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
260 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
261 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
262 					struct btrfsic_block_hashtable *h);
263 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
264 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
265 		struct block_device *bdev,
266 		u64 dev_bytenr,
267 		struct btrfsic_block_hashtable *h);
268 static void btrfsic_block_link_hashtable_init(
269 		struct btrfsic_block_link_hashtable *h);
270 static void btrfsic_block_link_hashtable_add(
271 		struct btrfsic_block_link *l,
272 		struct btrfsic_block_link_hashtable *h);
273 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
274 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
275 		struct block_device *bdev_ref_to,
276 		u64 dev_bytenr_ref_to,
277 		struct block_device *bdev_ref_from,
278 		u64 dev_bytenr_ref_from,
279 		struct btrfsic_block_link_hashtable *h);
280 static void btrfsic_dev_state_hashtable_init(
281 		struct btrfsic_dev_state_hashtable *h);
282 static void btrfsic_dev_state_hashtable_add(
283 		struct btrfsic_dev_state *ds,
284 		struct btrfsic_dev_state_hashtable *h);
285 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
286 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
287 		struct block_device *bdev,
288 		struct btrfsic_dev_state_hashtable *h);
289 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
290 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
291 static int btrfsic_process_superblock(struct btrfsic_state *state,
292 				      struct btrfs_fs_devices *fs_devices);
293 static int btrfsic_process_metablock(struct btrfsic_state *state,
294 				     struct btrfsic_block *block,
295 				     struct btrfsic_block_data_ctx *block_ctx,
296 				     int limit_nesting, int force_iodone_flag);
297 static void btrfsic_read_from_block_data(
298 	struct btrfsic_block_data_ctx *block_ctx,
299 	void *dst, u32 offset, size_t len);
300 static int btrfsic_create_link_to_next_block(
301 		struct btrfsic_state *state,
302 		struct btrfsic_block *block,
303 		struct btrfsic_block_data_ctx
304 		*block_ctx, u64 next_bytenr,
305 		int limit_nesting,
306 		struct btrfsic_block_data_ctx *next_block_ctx,
307 		struct btrfsic_block **next_blockp,
308 		int force_iodone_flag,
309 		int *num_copiesp, int *mirror_nump,
310 		struct btrfs_disk_key *disk_key,
311 		u64 parent_generation);
312 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
313 				      struct btrfsic_block *block,
314 				      struct btrfsic_block_data_ctx *block_ctx,
315 				      u32 item_offset, int force_iodone_flag);
316 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
317 			     struct btrfsic_block_data_ctx *block_ctx_out,
318 			     int mirror_num);
319 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
320 				  u32 len, struct block_device *bdev,
321 				  struct btrfsic_block_data_ctx *block_ctx_out);
322 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
323 static int btrfsic_read_block(struct btrfsic_state *state,
324 			      struct btrfsic_block_data_ctx *block_ctx);
325 static void btrfsic_dump_database(struct btrfsic_state *state);
326 static void btrfsic_complete_bio_end_io(struct bio *bio, int err);
327 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
328 				     char **datav, unsigned int num_pages);
329 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
330 					  u64 dev_bytenr, char **mapped_datav,
331 					  unsigned int num_pages,
332 					  struct bio *bio, int *bio_is_patched,
333 					  struct buffer_head *bh,
334 					  int submit_bio_bh_rw);
335 static int btrfsic_process_written_superblock(
336 		struct btrfsic_state *state,
337 		struct btrfsic_block *const block,
338 		struct btrfs_super_block *const super_hdr);
339 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
340 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
341 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
342 					      const struct btrfsic_block *block,
343 					      int recursion_level);
344 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
345 					struct btrfsic_block *const block,
346 					int recursion_level);
347 static void btrfsic_print_add_link(const struct btrfsic_state *state,
348 				   const struct btrfsic_block_link *l);
349 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
350 				   const struct btrfsic_block_link *l);
351 static char btrfsic_get_block_type(const struct btrfsic_state *state,
352 				   const struct btrfsic_block *block);
353 static void btrfsic_dump_tree(const struct btrfsic_state *state);
354 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
355 				  const struct btrfsic_block *block,
356 				  int indent_level);
357 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
358 		struct btrfsic_state *state,
359 		struct btrfsic_block_data_ctx *next_block_ctx,
360 		struct btrfsic_block *next_block,
361 		struct btrfsic_block *from_block,
362 		u64 parent_generation);
363 static struct btrfsic_block *btrfsic_block_lookup_or_add(
364 		struct btrfsic_state *state,
365 		struct btrfsic_block_data_ctx *block_ctx,
366 		const char *additional_string,
367 		int is_metadata,
368 		int is_iodone,
369 		int never_written,
370 		int mirror_num,
371 		int *was_created);
372 static int btrfsic_process_superblock_dev_mirror(
373 		struct btrfsic_state *state,
374 		struct btrfsic_dev_state *dev_state,
375 		struct btrfs_device *device,
376 		int superblock_mirror_num,
377 		struct btrfsic_dev_state **selected_dev_state,
378 		struct btrfs_super_block *selected_super);
379 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
380 		struct block_device *bdev);
381 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
382 					   u64 bytenr,
383 					   struct btrfsic_dev_state *dev_state,
384 					   u64 dev_bytenr);
385 
386 static struct mutex btrfsic_mutex;
387 static int btrfsic_is_initialized;
388 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
389 
390 
391 static void btrfsic_block_init(struct btrfsic_block *b)
392 {
393 	b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
394 	b->dev_state = NULL;
395 	b->dev_bytenr = 0;
396 	b->logical_bytenr = 0;
397 	b->generation = BTRFSIC_GENERATION_UNKNOWN;
398 	b->disk_key.objectid = 0;
399 	b->disk_key.type = 0;
400 	b->disk_key.offset = 0;
401 	b->is_metadata = 0;
402 	b->is_superblock = 0;
403 	b->is_iodone = 0;
404 	b->iodone_w_error = 0;
405 	b->never_written = 0;
406 	b->mirror_num = 0;
407 	b->next_in_same_bio = NULL;
408 	b->orig_bio_bh_private = NULL;
409 	b->orig_bio_bh_end_io.bio = NULL;
410 	INIT_LIST_HEAD(&b->collision_resolving_node);
411 	INIT_LIST_HEAD(&b->all_blocks_node);
412 	INIT_LIST_HEAD(&b->ref_to_list);
413 	INIT_LIST_HEAD(&b->ref_from_list);
414 	b->submit_bio_bh_rw = 0;
415 	b->flush_gen = 0;
416 }
417 
418 static struct btrfsic_block *btrfsic_block_alloc(void)
419 {
420 	struct btrfsic_block *b;
421 
422 	b = kzalloc(sizeof(*b), GFP_NOFS);
423 	if (NULL != b)
424 		btrfsic_block_init(b);
425 
426 	return b;
427 }
428 
429 static void btrfsic_block_free(struct btrfsic_block *b)
430 {
431 	BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
432 	kfree(b);
433 }
434 
435 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
436 {
437 	l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
438 	l->ref_cnt = 1;
439 	INIT_LIST_HEAD(&l->node_ref_to);
440 	INIT_LIST_HEAD(&l->node_ref_from);
441 	INIT_LIST_HEAD(&l->collision_resolving_node);
442 	l->block_ref_to = NULL;
443 	l->block_ref_from = NULL;
444 }
445 
446 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
447 {
448 	struct btrfsic_block_link *l;
449 
450 	l = kzalloc(sizeof(*l), GFP_NOFS);
451 	if (NULL != l)
452 		btrfsic_block_link_init(l);
453 
454 	return l;
455 }
456 
457 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
458 {
459 	BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
460 	kfree(l);
461 }
462 
463 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
464 {
465 	ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
466 	ds->bdev = NULL;
467 	ds->state = NULL;
468 	ds->name[0] = '\0';
469 	INIT_LIST_HEAD(&ds->collision_resolving_node);
470 	ds->last_flush_gen = 0;
471 	btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
472 	ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
473 	ds->dummy_block_for_bio_bh_flush.dev_state = ds;
474 }
475 
476 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
477 {
478 	struct btrfsic_dev_state *ds;
479 
480 	ds = kzalloc(sizeof(*ds), GFP_NOFS);
481 	if (NULL != ds)
482 		btrfsic_dev_state_init(ds);
483 
484 	return ds;
485 }
486 
487 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
488 {
489 	BUG_ON(!(NULL == ds ||
490 		 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
491 	kfree(ds);
492 }
493 
494 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
495 {
496 	int i;
497 
498 	for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
499 		INIT_LIST_HEAD(h->table + i);
500 }
501 
502 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
503 					struct btrfsic_block_hashtable *h)
504 {
505 	const unsigned int hashval =
506 	    (((unsigned int)(b->dev_bytenr >> 16)) ^
507 	     ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
508 	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
509 
510 	list_add(&b->collision_resolving_node, h->table + hashval);
511 }
512 
513 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
514 {
515 	list_del(&b->collision_resolving_node);
516 }
517 
518 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
519 		struct block_device *bdev,
520 		u64 dev_bytenr,
521 		struct btrfsic_block_hashtable *h)
522 {
523 	const unsigned int hashval =
524 	    (((unsigned int)(dev_bytenr >> 16)) ^
525 	     ((unsigned int)((uintptr_t)bdev))) &
526 	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
527 	struct list_head *elem;
528 
529 	list_for_each(elem, h->table + hashval) {
530 		struct btrfsic_block *const b =
531 		    list_entry(elem, struct btrfsic_block,
532 			       collision_resolving_node);
533 
534 		if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
535 			return b;
536 	}
537 
538 	return NULL;
539 }
540 
541 static void btrfsic_block_link_hashtable_init(
542 		struct btrfsic_block_link_hashtable *h)
543 {
544 	int i;
545 
546 	for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
547 		INIT_LIST_HEAD(h->table + i);
548 }
549 
550 static void btrfsic_block_link_hashtable_add(
551 		struct btrfsic_block_link *l,
552 		struct btrfsic_block_link_hashtable *h)
553 {
554 	const unsigned int hashval =
555 	    (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
556 	     ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
557 	     ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
558 	     ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
559 	     & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
560 
561 	BUG_ON(NULL == l->block_ref_to);
562 	BUG_ON(NULL == l->block_ref_from);
563 	list_add(&l->collision_resolving_node, h->table + hashval);
564 }
565 
566 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
567 {
568 	list_del(&l->collision_resolving_node);
569 }
570 
571 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
572 		struct block_device *bdev_ref_to,
573 		u64 dev_bytenr_ref_to,
574 		struct block_device *bdev_ref_from,
575 		u64 dev_bytenr_ref_from,
576 		struct btrfsic_block_link_hashtable *h)
577 {
578 	const unsigned int hashval =
579 	    (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
580 	     ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
581 	     ((unsigned int)((uintptr_t)bdev_ref_to)) ^
582 	     ((unsigned int)((uintptr_t)bdev_ref_from))) &
583 	     (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
584 	struct list_head *elem;
585 
586 	list_for_each(elem, h->table + hashval) {
587 		struct btrfsic_block_link *const l =
588 		    list_entry(elem, struct btrfsic_block_link,
589 			       collision_resolving_node);
590 
591 		BUG_ON(NULL == l->block_ref_to);
592 		BUG_ON(NULL == l->block_ref_from);
593 		if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
594 		    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
595 		    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
596 		    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
597 			return l;
598 	}
599 
600 	return NULL;
601 }
602 
603 static void btrfsic_dev_state_hashtable_init(
604 		struct btrfsic_dev_state_hashtable *h)
605 {
606 	int i;
607 
608 	for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
609 		INIT_LIST_HEAD(h->table + i);
610 }
611 
612 static void btrfsic_dev_state_hashtable_add(
613 		struct btrfsic_dev_state *ds,
614 		struct btrfsic_dev_state_hashtable *h)
615 {
616 	const unsigned int hashval =
617 	    (((unsigned int)((uintptr_t)ds->bdev)) &
618 	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
619 
620 	list_add(&ds->collision_resolving_node, h->table + hashval);
621 }
622 
623 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
624 {
625 	list_del(&ds->collision_resolving_node);
626 }
627 
628 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
629 		struct block_device *bdev,
630 		struct btrfsic_dev_state_hashtable *h)
631 {
632 	const unsigned int hashval =
633 	    (((unsigned int)((uintptr_t)bdev)) &
634 	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
635 	struct list_head *elem;
636 
637 	list_for_each(elem, h->table + hashval) {
638 		struct btrfsic_dev_state *const ds =
639 		    list_entry(elem, struct btrfsic_dev_state,
640 			       collision_resolving_node);
641 
642 		if (ds->bdev == bdev)
643 			return ds;
644 	}
645 
646 	return NULL;
647 }
648 
649 static int btrfsic_process_superblock(struct btrfsic_state *state,
650 				      struct btrfs_fs_devices *fs_devices)
651 {
652 	int ret = 0;
653 	struct btrfs_super_block *selected_super;
654 	struct list_head *dev_head = &fs_devices->devices;
655 	struct btrfs_device *device;
656 	struct btrfsic_dev_state *selected_dev_state = NULL;
657 	int pass;
658 
659 	BUG_ON(NULL == state);
660 	selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
661 	if (NULL == selected_super) {
662 		printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
663 		return -1;
664 	}
665 
666 	list_for_each_entry(device, dev_head, dev_list) {
667 		int i;
668 		struct btrfsic_dev_state *dev_state;
669 
670 		if (!device->bdev || !device->name)
671 			continue;
672 
673 		dev_state = btrfsic_dev_state_lookup(device->bdev);
674 		BUG_ON(NULL == dev_state);
675 		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
676 			ret = btrfsic_process_superblock_dev_mirror(
677 					state, dev_state, device, i,
678 					&selected_dev_state, selected_super);
679 			if (0 != ret && 0 == i) {
680 				kfree(selected_super);
681 				return ret;
682 			}
683 		}
684 	}
685 
686 	if (NULL == state->latest_superblock) {
687 		printk(KERN_INFO "btrfsic: no superblock found!\n");
688 		kfree(selected_super);
689 		return -1;
690 	}
691 
692 	state->csum_size = btrfs_super_csum_size(selected_super);
693 
694 	for (pass = 0; pass < 3; pass++) {
695 		int num_copies;
696 		int mirror_num;
697 		u64 next_bytenr;
698 
699 		switch (pass) {
700 		case 0:
701 			next_bytenr = btrfs_super_root(selected_super);
702 			if (state->print_mask &
703 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
704 				printk(KERN_INFO "root@%llu\n",
705 				       (unsigned long long)next_bytenr);
706 			break;
707 		case 1:
708 			next_bytenr = btrfs_super_chunk_root(selected_super);
709 			if (state->print_mask &
710 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
711 				printk(KERN_INFO "chunk@%llu\n",
712 				       (unsigned long long)next_bytenr);
713 			break;
714 		case 2:
715 			next_bytenr = btrfs_super_log_root(selected_super);
716 			if (0 == next_bytenr)
717 				continue;
718 			if (state->print_mask &
719 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
720 				printk(KERN_INFO "log@%llu\n",
721 				       (unsigned long long)next_bytenr);
722 			break;
723 		}
724 
725 		num_copies =
726 		    btrfs_num_copies(state->root->fs_info,
727 				     next_bytenr, state->metablock_size);
728 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
729 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
730 			       (unsigned long long)next_bytenr, num_copies);
731 
732 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
733 			struct btrfsic_block *next_block;
734 			struct btrfsic_block_data_ctx tmp_next_block_ctx;
735 			struct btrfsic_block_link *l;
736 
737 			ret = btrfsic_map_block(state, next_bytenr,
738 						state->metablock_size,
739 						&tmp_next_block_ctx,
740 						mirror_num);
741 			if (ret) {
742 				printk(KERN_INFO "btrfsic:"
743 				       " btrfsic_map_block(root @%llu,"
744 				       " mirror %d) failed!\n",
745 				       (unsigned long long)next_bytenr,
746 				       mirror_num);
747 				kfree(selected_super);
748 				return -1;
749 			}
750 
751 			next_block = btrfsic_block_hashtable_lookup(
752 					tmp_next_block_ctx.dev->bdev,
753 					tmp_next_block_ctx.dev_bytenr,
754 					&state->block_hashtable);
755 			BUG_ON(NULL == next_block);
756 
757 			l = btrfsic_block_link_hashtable_lookup(
758 					tmp_next_block_ctx.dev->bdev,
759 					tmp_next_block_ctx.dev_bytenr,
760 					state->latest_superblock->dev_state->
761 					bdev,
762 					state->latest_superblock->dev_bytenr,
763 					&state->block_link_hashtable);
764 			BUG_ON(NULL == l);
765 
766 			ret = btrfsic_read_block(state, &tmp_next_block_ctx);
767 			if (ret < (int)PAGE_CACHE_SIZE) {
768 				printk(KERN_INFO
769 				       "btrfsic: read @logical %llu failed!\n",
770 				       (unsigned long long)
771 				       tmp_next_block_ctx.start);
772 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
773 				kfree(selected_super);
774 				return -1;
775 			}
776 
777 			ret = btrfsic_process_metablock(state,
778 							next_block,
779 							&tmp_next_block_ctx,
780 							BTRFS_MAX_LEVEL + 3, 1);
781 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
782 		}
783 	}
784 
785 	kfree(selected_super);
786 	return ret;
787 }
788 
789 static int btrfsic_process_superblock_dev_mirror(
790 		struct btrfsic_state *state,
791 		struct btrfsic_dev_state *dev_state,
792 		struct btrfs_device *device,
793 		int superblock_mirror_num,
794 		struct btrfsic_dev_state **selected_dev_state,
795 		struct btrfs_super_block *selected_super)
796 {
797 	struct btrfs_super_block *super_tmp;
798 	u64 dev_bytenr;
799 	struct buffer_head *bh;
800 	struct btrfsic_block *superblock_tmp;
801 	int pass;
802 	struct block_device *const superblock_bdev = device->bdev;
803 
804 	/* super block bytenr is always the unmapped device bytenr */
805 	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
806 	if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
807 		return -1;
808 	bh = __bread(superblock_bdev, dev_bytenr / 4096,
809 		     BTRFS_SUPER_INFO_SIZE);
810 	if (NULL == bh)
811 		return -1;
812 	super_tmp = (struct btrfs_super_block *)
813 	    (bh->b_data + (dev_bytenr & 4095));
814 
815 	if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
816 	    super_tmp->magic != cpu_to_le64(BTRFS_MAGIC) ||
817 	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
818 	    btrfs_super_nodesize(super_tmp) != state->metablock_size ||
819 	    btrfs_super_leafsize(super_tmp) != state->metablock_size ||
820 	    btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
821 		brelse(bh);
822 		return 0;
823 	}
824 
825 	superblock_tmp =
826 	    btrfsic_block_hashtable_lookup(superblock_bdev,
827 					   dev_bytenr,
828 					   &state->block_hashtable);
829 	if (NULL == superblock_tmp) {
830 		superblock_tmp = btrfsic_block_alloc();
831 		if (NULL == superblock_tmp) {
832 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
833 			brelse(bh);
834 			return -1;
835 		}
836 		/* for superblock, only the dev_bytenr makes sense */
837 		superblock_tmp->dev_bytenr = dev_bytenr;
838 		superblock_tmp->dev_state = dev_state;
839 		superblock_tmp->logical_bytenr = dev_bytenr;
840 		superblock_tmp->generation = btrfs_super_generation(super_tmp);
841 		superblock_tmp->is_metadata = 1;
842 		superblock_tmp->is_superblock = 1;
843 		superblock_tmp->is_iodone = 1;
844 		superblock_tmp->never_written = 0;
845 		superblock_tmp->mirror_num = 1 + superblock_mirror_num;
846 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
847 			printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
848 				     " @%llu (%s/%llu/%d)\n",
849 				     superblock_bdev,
850 				     rcu_str_deref(device->name),
851 				     (unsigned long long)dev_bytenr,
852 				     dev_state->name,
853 				     (unsigned long long)dev_bytenr,
854 				     superblock_mirror_num);
855 		list_add(&superblock_tmp->all_blocks_node,
856 			 &state->all_blocks_list);
857 		btrfsic_block_hashtable_add(superblock_tmp,
858 					    &state->block_hashtable);
859 	}
860 
861 	/* select the one with the highest generation field */
862 	if (btrfs_super_generation(super_tmp) >
863 	    state->max_superblock_generation ||
864 	    0 == state->max_superblock_generation) {
865 		memcpy(selected_super, super_tmp, sizeof(*selected_super));
866 		*selected_dev_state = dev_state;
867 		state->max_superblock_generation =
868 		    btrfs_super_generation(super_tmp);
869 		state->latest_superblock = superblock_tmp;
870 	}
871 
872 	for (pass = 0; pass < 3; pass++) {
873 		u64 next_bytenr;
874 		int num_copies;
875 		int mirror_num;
876 		const char *additional_string = NULL;
877 		struct btrfs_disk_key tmp_disk_key;
878 
879 		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
880 		tmp_disk_key.offset = 0;
881 		switch (pass) {
882 		case 0:
883 			tmp_disk_key.objectid =
884 			    cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
885 			additional_string = "initial root ";
886 			next_bytenr = btrfs_super_root(super_tmp);
887 			break;
888 		case 1:
889 			tmp_disk_key.objectid =
890 			    cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
891 			additional_string = "initial chunk ";
892 			next_bytenr = btrfs_super_chunk_root(super_tmp);
893 			break;
894 		case 2:
895 			tmp_disk_key.objectid =
896 			    cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
897 			additional_string = "initial log ";
898 			next_bytenr = btrfs_super_log_root(super_tmp);
899 			if (0 == next_bytenr)
900 				continue;
901 			break;
902 		}
903 
904 		num_copies =
905 		    btrfs_num_copies(state->root->fs_info,
906 				     next_bytenr, state->metablock_size);
907 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
908 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
909 			       (unsigned long long)next_bytenr, num_copies);
910 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
911 			struct btrfsic_block *next_block;
912 			struct btrfsic_block_data_ctx tmp_next_block_ctx;
913 			struct btrfsic_block_link *l;
914 
915 			if (btrfsic_map_block(state, next_bytenr,
916 					      state->metablock_size,
917 					      &tmp_next_block_ctx,
918 					      mirror_num)) {
919 				printk(KERN_INFO "btrfsic: btrfsic_map_block("
920 				       "bytenr @%llu, mirror %d) failed!\n",
921 				       (unsigned long long)next_bytenr,
922 				       mirror_num);
923 				brelse(bh);
924 				return -1;
925 			}
926 
927 			next_block = btrfsic_block_lookup_or_add(
928 					state, &tmp_next_block_ctx,
929 					additional_string, 1, 1, 0,
930 					mirror_num, NULL);
931 			if (NULL == next_block) {
932 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
933 				brelse(bh);
934 				return -1;
935 			}
936 
937 			next_block->disk_key = tmp_disk_key;
938 			next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
939 			l = btrfsic_block_link_lookup_or_add(
940 					state, &tmp_next_block_ctx,
941 					next_block, superblock_tmp,
942 					BTRFSIC_GENERATION_UNKNOWN);
943 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
944 			if (NULL == l) {
945 				brelse(bh);
946 				return -1;
947 			}
948 		}
949 	}
950 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
951 		btrfsic_dump_tree_sub(state, superblock_tmp, 0);
952 
953 	brelse(bh);
954 	return 0;
955 }
956 
957 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
958 {
959 	struct btrfsic_stack_frame *sf;
960 
961 	sf = kzalloc(sizeof(*sf), GFP_NOFS);
962 	if (NULL == sf)
963 		printk(KERN_INFO "btrfsic: alloc memory failed!\n");
964 	else
965 		sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
966 	return sf;
967 }
968 
969 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
970 {
971 	BUG_ON(!(NULL == sf ||
972 		 BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
973 	kfree(sf);
974 }
975 
976 static int btrfsic_process_metablock(
977 		struct btrfsic_state *state,
978 		struct btrfsic_block *const first_block,
979 		struct btrfsic_block_data_ctx *const first_block_ctx,
980 		int first_limit_nesting, int force_iodone_flag)
981 {
982 	struct btrfsic_stack_frame initial_stack_frame = { 0 };
983 	struct btrfsic_stack_frame *sf;
984 	struct btrfsic_stack_frame *next_stack;
985 	struct btrfs_header *const first_hdr =
986 		(struct btrfs_header *)first_block_ctx->datav[0];
987 
988 	BUG_ON(!first_hdr);
989 	sf = &initial_stack_frame;
990 	sf->error = 0;
991 	sf->i = -1;
992 	sf->limit_nesting = first_limit_nesting;
993 	sf->block = first_block;
994 	sf->block_ctx = first_block_ctx;
995 	sf->next_block = NULL;
996 	sf->hdr = first_hdr;
997 	sf->prev = NULL;
998 
999 continue_with_new_stack_frame:
1000 	sf->block->generation = le64_to_cpu(sf->hdr->generation);
1001 	if (0 == sf->hdr->level) {
1002 		struct btrfs_leaf *const leafhdr =
1003 		    (struct btrfs_leaf *)sf->hdr;
1004 
1005 		if (-1 == sf->i) {
1006 			sf->nr = le32_to_cpu(leafhdr->header.nritems);
1007 
1008 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1009 				printk(KERN_INFO
1010 				       "leaf %llu items %d generation %llu"
1011 				       " owner %llu\n",
1012 				       (unsigned long long)
1013 				       sf->block_ctx->start,
1014 				       sf->nr,
1015 				       (unsigned long long)
1016 				       le64_to_cpu(leafhdr->header.generation),
1017 				       (unsigned long long)
1018 				       le64_to_cpu(leafhdr->header.owner));
1019 		}
1020 
1021 continue_with_current_leaf_stack_frame:
1022 		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1023 			sf->i++;
1024 			sf->num_copies = 0;
1025 		}
1026 
1027 		if (sf->i < sf->nr) {
1028 			struct btrfs_item disk_item;
1029 			u32 disk_item_offset =
1030 				(uintptr_t)(leafhdr->items + sf->i) -
1031 				(uintptr_t)leafhdr;
1032 			struct btrfs_disk_key *disk_key;
1033 			u8 type;
1034 			u32 item_offset;
1035 			u32 item_size;
1036 
1037 			if (disk_item_offset + sizeof(struct btrfs_item) >
1038 			    sf->block_ctx->len) {
1039 leaf_item_out_of_bounce_error:
1040 				printk(KERN_INFO
1041 				       "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1042 				       sf->block_ctx->start,
1043 				       sf->block_ctx->dev->name);
1044 				goto one_stack_frame_backwards;
1045 			}
1046 			btrfsic_read_from_block_data(sf->block_ctx,
1047 						     &disk_item,
1048 						     disk_item_offset,
1049 						     sizeof(struct btrfs_item));
1050 			item_offset = le32_to_cpu(disk_item.offset);
1051 			item_size = le32_to_cpu(disk_item.size);
1052 			disk_key = &disk_item.key;
1053 			type = disk_key->type;
1054 
1055 			if (BTRFS_ROOT_ITEM_KEY == type) {
1056 				struct btrfs_root_item root_item;
1057 				u32 root_item_offset;
1058 				u64 next_bytenr;
1059 
1060 				root_item_offset = item_offset +
1061 					offsetof(struct btrfs_leaf, items);
1062 				if (root_item_offset + item_size >
1063 				    sf->block_ctx->len)
1064 					goto leaf_item_out_of_bounce_error;
1065 				btrfsic_read_from_block_data(
1066 					sf->block_ctx, &root_item,
1067 					root_item_offset,
1068 					item_size);
1069 				next_bytenr = le64_to_cpu(root_item.bytenr);
1070 
1071 				sf->error =
1072 				    btrfsic_create_link_to_next_block(
1073 						state,
1074 						sf->block,
1075 						sf->block_ctx,
1076 						next_bytenr,
1077 						sf->limit_nesting,
1078 						&sf->next_block_ctx,
1079 						&sf->next_block,
1080 						force_iodone_flag,
1081 						&sf->num_copies,
1082 						&sf->mirror_num,
1083 						disk_key,
1084 						le64_to_cpu(root_item.
1085 						generation));
1086 				if (sf->error)
1087 					goto one_stack_frame_backwards;
1088 
1089 				if (NULL != sf->next_block) {
1090 					struct btrfs_header *const next_hdr =
1091 					    (struct btrfs_header *)
1092 					    sf->next_block_ctx.datav[0];
1093 
1094 					next_stack =
1095 					    btrfsic_stack_frame_alloc();
1096 					if (NULL == next_stack) {
1097 						btrfsic_release_block_ctx(
1098 								&sf->
1099 								next_block_ctx);
1100 						goto one_stack_frame_backwards;
1101 					}
1102 
1103 					next_stack->i = -1;
1104 					next_stack->block = sf->next_block;
1105 					next_stack->block_ctx =
1106 					    &sf->next_block_ctx;
1107 					next_stack->next_block = NULL;
1108 					next_stack->hdr = next_hdr;
1109 					next_stack->limit_nesting =
1110 					    sf->limit_nesting - 1;
1111 					next_stack->prev = sf;
1112 					sf = next_stack;
1113 					goto continue_with_new_stack_frame;
1114 				}
1115 			} else if (BTRFS_EXTENT_DATA_KEY == type &&
1116 				   state->include_extent_data) {
1117 				sf->error = btrfsic_handle_extent_data(
1118 						state,
1119 						sf->block,
1120 						sf->block_ctx,
1121 						item_offset,
1122 						force_iodone_flag);
1123 				if (sf->error)
1124 					goto one_stack_frame_backwards;
1125 			}
1126 
1127 			goto continue_with_current_leaf_stack_frame;
1128 		}
1129 	} else {
1130 		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1131 
1132 		if (-1 == sf->i) {
1133 			sf->nr = le32_to_cpu(nodehdr->header.nritems);
1134 
1135 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1136 				printk(KERN_INFO "node %llu level %d items %d"
1137 				       " generation %llu owner %llu\n",
1138 				       (unsigned long long)
1139 				       sf->block_ctx->start,
1140 				       nodehdr->header.level, sf->nr,
1141 				       (unsigned long long)
1142 				       le64_to_cpu(nodehdr->header.generation),
1143 				       (unsigned long long)
1144 				       le64_to_cpu(nodehdr->header.owner));
1145 		}
1146 
1147 continue_with_current_node_stack_frame:
1148 		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1149 			sf->i++;
1150 			sf->num_copies = 0;
1151 		}
1152 
1153 		if (sf->i < sf->nr) {
1154 			struct btrfs_key_ptr key_ptr;
1155 			u32 key_ptr_offset;
1156 			u64 next_bytenr;
1157 
1158 			key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1159 					  (uintptr_t)nodehdr;
1160 			if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1161 			    sf->block_ctx->len) {
1162 				printk(KERN_INFO
1163 				       "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1164 				       sf->block_ctx->start,
1165 				       sf->block_ctx->dev->name);
1166 				goto one_stack_frame_backwards;
1167 			}
1168 			btrfsic_read_from_block_data(
1169 				sf->block_ctx, &key_ptr, key_ptr_offset,
1170 				sizeof(struct btrfs_key_ptr));
1171 			next_bytenr = le64_to_cpu(key_ptr.blockptr);
1172 
1173 			sf->error = btrfsic_create_link_to_next_block(
1174 					state,
1175 					sf->block,
1176 					sf->block_ctx,
1177 					next_bytenr,
1178 					sf->limit_nesting,
1179 					&sf->next_block_ctx,
1180 					&sf->next_block,
1181 					force_iodone_flag,
1182 					&sf->num_copies,
1183 					&sf->mirror_num,
1184 					&key_ptr.key,
1185 					le64_to_cpu(key_ptr.generation));
1186 			if (sf->error)
1187 				goto one_stack_frame_backwards;
1188 
1189 			if (NULL != sf->next_block) {
1190 				struct btrfs_header *const next_hdr =
1191 				    (struct btrfs_header *)
1192 				    sf->next_block_ctx.datav[0];
1193 
1194 				next_stack = btrfsic_stack_frame_alloc();
1195 				if (NULL == next_stack)
1196 					goto one_stack_frame_backwards;
1197 
1198 				next_stack->i = -1;
1199 				next_stack->block = sf->next_block;
1200 				next_stack->block_ctx = &sf->next_block_ctx;
1201 				next_stack->next_block = NULL;
1202 				next_stack->hdr = next_hdr;
1203 				next_stack->limit_nesting =
1204 				    sf->limit_nesting - 1;
1205 				next_stack->prev = sf;
1206 				sf = next_stack;
1207 				goto continue_with_new_stack_frame;
1208 			}
1209 
1210 			goto continue_with_current_node_stack_frame;
1211 		}
1212 	}
1213 
1214 one_stack_frame_backwards:
1215 	if (NULL != sf->prev) {
1216 		struct btrfsic_stack_frame *const prev = sf->prev;
1217 
1218 		/* the one for the initial block is freed in the caller */
1219 		btrfsic_release_block_ctx(sf->block_ctx);
1220 
1221 		if (sf->error) {
1222 			prev->error = sf->error;
1223 			btrfsic_stack_frame_free(sf);
1224 			sf = prev;
1225 			goto one_stack_frame_backwards;
1226 		}
1227 
1228 		btrfsic_stack_frame_free(sf);
1229 		sf = prev;
1230 		goto continue_with_new_stack_frame;
1231 	} else {
1232 		BUG_ON(&initial_stack_frame != sf);
1233 	}
1234 
1235 	return sf->error;
1236 }
1237 
1238 static void btrfsic_read_from_block_data(
1239 	struct btrfsic_block_data_ctx *block_ctx,
1240 	void *dstv, u32 offset, size_t len)
1241 {
1242 	size_t cur;
1243 	size_t offset_in_page;
1244 	char *kaddr;
1245 	char *dst = (char *)dstv;
1246 	size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1247 	unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1248 
1249 	WARN_ON(offset + len > block_ctx->len);
1250 	offset_in_page = (start_offset + offset) &
1251 			 ((unsigned long)PAGE_CACHE_SIZE - 1);
1252 
1253 	while (len > 0) {
1254 		cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1255 		BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
1256 			    PAGE_CACHE_SHIFT);
1257 		kaddr = block_ctx->datav[i];
1258 		memcpy(dst, kaddr + offset_in_page, cur);
1259 
1260 		dst += cur;
1261 		len -= cur;
1262 		offset_in_page = 0;
1263 		i++;
1264 	}
1265 }
1266 
1267 static int btrfsic_create_link_to_next_block(
1268 		struct btrfsic_state *state,
1269 		struct btrfsic_block *block,
1270 		struct btrfsic_block_data_ctx *block_ctx,
1271 		u64 next_bytenr,
1272 		int limit_nesting,
1273 		struct btrfsic_block_data_ctx *next_block_ctx,
1274 		struct btrfsic_block **next_blockp,
1275 		int force_iodone_flag,
1276 		int *num_copiesp, int *mirror_nump,
1277 		struct btrfs_disk_key *disk_key,
1278 		u64 parent_generation)
1279 {
1280 	struct btrfsic_block *next_block = NULL;
1281 	int ret;
1282 	struct btrfsic_block_link *l;
1283 	int did_alloc_block_link;
1284 	int block_was_created;
1285 
1286 	*next_blockp = NULL;
1287 	if (0 == *num_copiesp) {
1288 		*num_copiesp =
1289 		    btrfs_num_copies(state->root->fs_info,
1290 				     next_bytenr, state->metablock_size);
1291 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1292 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1293 			       (unsigned long long)next_bytenr, *num_copiesp);
1294 		*mirror_nump = 1;
1295 	}
1296 
1297 	if (*mirror_nump > *num_copiesp)
1298 		return 0;
1299 
1300 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1301 		printk(KERN_INFO
1302 		       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1303 		       *mirror_nump);
1304 	ret = btrfsic_map_block(state, next_bytenr,
1305 				state->metablock_size,
1306 				next_block_ctx, *mirror_nump);
1307 	if (ret) {
1308 		printk(KERN_INFO
1309 		       "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1310 		       (unsigned long long)next_bytenr, *mirror_nump);
1311 		btrfsic_release_block_ctx(next_block_ctx);
1312 		*next_blockp = NULL;
1313 		return -1;
1314 	}
1315 
1316 	next_block = btrfsic_block_lookup_or_add(state,
1317 						 next_block_ctx, "referenced ",
1318 						 1, force_iodone_flag,
1319 						 !force_iodone_flag,
1320 						 *mirror_nump,
1321 						 &block_was_created);
1322 	if (NULL == next_block) {
1323 		btrfsic_release_block_ctx(next_block_ctx);
1324 		*next_blockp = NULL;
1325 		return -1;
1326 	}
1327 	if (block_was_created) {
1328 		l = NULL;
1329 		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1330 	} else {
1331 		if (next_block->logical_bytenr != next_bytenr &&
1332 		    !(!next_block->is_metadata &&
1333 		      0 == next_block->logical_bytenr)) {
1334 			printk(KERN_INFO
1335 			       "Referenced block @%llu (%s/%llu/%d)"
1336 			       " found in hash table, %c,"
1337 			       " bytenr mismatch (!= stored %llu).\n",
1338 			       (unsigned long long)next_bytenr,
1339 			       next_block_ctx->dev->name,
1340 			       (unsigned long long)next_block_ctx->dev_bytenr,
1341 			       *mirror_nump,
1342 			       btrfsic_get_block_type(state, next_block),
1343 			       (unsigned long long)next_block->logical_bytenr);
1344 		} else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1345 			printk(KERN_INFO
1346 			       "Referenced block @%llu (%s/%llu/%d)"
1347 			       " found in hash table, %c.\n",
1348 			       (unsigned long long)next_bytenr,
1349 			       next_block_ctx->dev->name,
1350 			       (unsigned long long)next_block_ctx->dev_bytenr,
1351 			       *mirror_nump,
1352 			       btrfsic_get_block_type(state, next_block));
1353 		next_block->logical_bytenr = next_bytenr;
1354 
1355 		next_block->mirror_num = *mirror_nump;
1356 		l = btrfsic_block_link_hashtable_lookup(
1357 				next_block_ctx->dev->bdev,
1358 				next_block_ctx->dev_bytenr,
1359 				block_ctx->dev->bdev,
1360 				block_ctx->dev_bytenr,
1361 				&state->block_link_hashtable);
1362 	}
1363 
1364 	next_block->disk_key = *disk_key;
1365 	if (NULL == l) {
1366 		l = btrfsic_block_link_alloc();
1367 		if (NULL == l) {
1368 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1369 			btrfsic_release_block_ctx(next_block_ctx);
1370 			*next_blockp = NULL;
1371 			return -1;
1372 		}
1373 
1374 		did_alloc_block_link = 1;
1375 		l->block_ref_to = next_block;
1376 		l->block_ref_from = block;
1377 		l->ref_cnt = 1;
1378 		l->parent_generation = parent_generation;
1379 
1380 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1381 			btrfsic_print_add_link(state, l);
1382 
1383 		list_add(&l->node_ref_to, &block->ref_to_list);
1384 		list_add(&l->node_ref_from, &next_block->ref_from_list);
1385 
1386 		btrfsic_block_link_hashtable_add(l,
1387 						 &state->block_link_hashtable);
1388 	} else {
1389 		did_alloc_block_link = 0;
1390 		if (0 == limit_nesting) {
1391 			l->ref_cnt++;
1392 			l->parent_generation = parent_generation;
1393 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1394 				btrfsic_print_add_link(state, l);
1395 		}
1396 	}
1397 
1398 	if (limit_nesting > 0 && did_alloc_block_link) {
1399 		ret = btrfsic_read_block(state, next_block_ctx);
1400 		if (ret < (int)next_block_ctx->len) {
1401 			printk(KERN_INFO
1402 			       "btrfsic: read block @logical %llu failed!\n",
1403 			       (unsigned long long)next_bytenr);
1404 			btrfsic_release_block_ctx(next_block_ctx);
1405 			*next_blockp = NULL;
1406 			return -1;
1407 		}
1408 
1409 		*next_blockp = next_block;
1410 	} else {
1411 		*next_blockp = NULL;
1412 	}
1413 	(*mirror_nump)++;
1414 
1415 	return 0;
1416 }
1417 
1418 static int btrfsic_handle_extent_data(
1419 		struct btrfsic_state *state,
1420 		struct btrfsic_block *block,
1421 		struct btrfsic_block_data_ctx *block_ctx,
1422 		u32 item_offset, int force_iodone_flag)
1423 {
1424 	int ret;
1425 	struct btrfs_file_extent_item file_extent_item;
1426 	u64 file_extent_item_offset;
1427 	u64 next_bytenr;
1428 	u64 num_bytes;
1429 	u64 generation;
1430 	struct btrfsic_block_link *l;
1431 
1432 	file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1433 				  item_offset;
1434 	if (file_extent_item_offset +
1435 	    offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1436 	    block_ctx->len) {
1437 		printk(KERN_INFO
1438 		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1439 		       block_ctx->start, block_ctx->dev->name);
1440 		return -1;
1441 	}
1442 
1443 	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1444 		file_extent_item_offset,
1445 		offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1446 	if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1447 	    ((u64)0) == le64_to_cpu(file_extent_item.disk_bytenr)) {
1448 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1449 			printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1450 			       file_extent_item.type,
1451 			       (unsigned long long)
1452 			       le64_to_cpu(file_extent_item.disk_bytenr));
1453 		return 0;
1454 	}
1455 
1456 	if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1457 	    block_ctx->len) {
1458 		printk(KERN_INFO
1459 		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1460 		       block_ctx->start, block_ctx->dev->name);
1461 		return -1;
1462 	}
1463 	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1464 				     file_extent_item_offset,
1465 				     sizeof(struct btrfs_file_extent_item));
1466 	next_bytenr = le64_to_cpu(file_extent_item.disk_bytenr) +
1467 		      le64_to_cpu(file_extent_item.offset);
1468 	generation = le64_to_cpu(file_extent_item.generation);
1469 	num_bytes = le64_to_cpu(file_extent_item.num_bytes);
1470 	generation = le64_to_cpu(file_extent_item.generation);
1471 
1472 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1473 		printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1474 		       " offset = %llu, num_bytes = %llu\n",
1475 		       file_extent_item.type,
1476 		       (unsigned long long)
1477 		       le64_to_cpu(file_extent_item.disk_bytenr),
1478 		       (unsigned long long)le64_to_cpu(file_extent_item.offset),
1479 		       (unsigned long long)num_bytes);
1480 	while (num_bytes > 0) {
1481 		u32 chunk_len;
1482 		int num_copies;
1483 		int mirror_num;
1484 
1485 		if (num_bytes > state->datablock_size)
1486 			chunk_len = state->datablock_size;
1487 		else
1488 			chunk_len = num_bytes;
1489 
1490 		num_copies =
1491 		    btrfs_num_copies(state->root->fs_info,
1492 				     next_bytenr, state->datablock_size);
1493 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1494 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1495 			       (unsigned long long)next_bytenr, num_copies);
1496 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1497 			struct btrfsic_block_data_ctx next_block_ctx;
1498 			struct btrfsic_block *next_block;
1499 			int block_was_created;
1500 
1501 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1502 				printk(KERN_INFO "btrfsic_handle_extent_data("
1503 				       "mirror_num=%d)\n", mirror_num);
1504 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1505 				printk(KERN_INFO
1506 				       "\tdisk_bytenr = %llu, num_bytes %u\n",
1507 				       (unsigned long long)next_bytenr,
1508 				       chunk_len);
1509 			ret = btrfsic_map_block(state, next_bytenr,
1510 						chunk_len, &next_block_ctx,
1511 						mirror_num);
1512 			if (ret) {
1513 				printk(KERN_INFO
1514 				       "btrfsic: btrfsic_map_block(@%llu,"
1515 				       " mirror=%d) failed!\n",
1516 				       (unsigned long long)next_bytenr,
1517 				       mirror_num);
1518 				return -1;
1519 			}
1520 
1521 			next_block = btrfsic_block_lookup_or_add(
1522 					state,
1523 					&next_block_ctx,
1524 					"referenced ",
1525 					0,
1526 					force_iodone_flag,
1527 					!force_iodone_flag,
1528 					mirror_num,
1529 					&block_was_created);
1530 			if (NULL == next_block) {
1531 				printk(KERN_INFO
1532 				       "btrfsic: error, kmalloc failed!\n");
1533 				btrfsic_release_block_ctx(&next_block_ctx);
1534 				return -1;
1535 			}
1536 			if (!block_was_created) {
1537 				if (next_block->logical_bytenr != next_bytenr &&
1538 				    !(!next_block->is_metadata &&
1539 				      0 == next_block->logical_bytenr)) {
1540 					printk(KERN_INFO
1541 					       "Referenced block"
1542 					       " @%llu (%s/%llu/%d)"
1543 					       " found in hash table, D,"
1544 					       " bytenr mismatch"
1545 					       " (!= stored %llu).\n",
1546 					       (unsigned long long)next_bytenr,
1547 					       next_block_ctx.dev->name,
1548 					       (unsigned long long)
1549 					       next_block_ctx.dev_bytenr,
1550 					       mirror_num,
1551 					       (unsigned long long)
1552 					       next_block->logical_bytenr);
1553 				}
1554 				next_block->logical_bytenr = next_bytenr;
1555 				next_block->mirror_num = mirror_num;
1556 			}
1557 
1558 			l = btrfsic_block_link_lookup_or_add(state,
1559 							     &next_block_ctx,
1560 							     next_block, block,
1561 							     generation);
1562 			btrfsic_release_block_ctx(&next_block_ctx);
1563 			if (NULL == l)
1564 				return -1;
1565 		}
1566 
1567 		next_bytenr += chunk_len;
1568 		num_bytes -= chunk_len;
1569 	}
1570 
1571 	return 0;
1572 }
1573 
1574 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1575 			     struct btrfsic_block_data_ctx *block_ctx_out,
1576 			     int mirror_num)
1577 {
1578 	int ret;
1579 	u64 length;
1580 	struct btrfs_bio *multi = NULL;
1581 	struct btrfs_device *device;
1582 
1583 	length = len;
1584 	ret = btrfs_map_block(state->root->fs_info, READ,
1585 			      bytenr, &length, &multi, mirror_num);
1586 
1587 	if (ret) {
1588 		block_ctx_out->start = 0;
1589 		block_ctx_out->dev_bytenr = 0;
1590 		block_ctx_out->len = 0;
1591 		block_ctx_out->dev = NULL;
1592 		block_ctx_out->datav = NULL;
1593 		block_ctx_out->pagev = NULL;
1594 		block_ctx_out->mem_to_free = NULL;
1595 
1596 		return ret;
1597 	}
1598 
1599 	device = multi->stripes[0].dev;
1600 	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1601 	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1602 	block_ctx_out->start = bytenr;
1603 	block_ctx_out->len = len;
1604 	block_ctx_out->datav = NULL;
1605 	block_ctx_out->pagev = NULL;
1606 	block_ctx_out->mem_to_free = NULL;
1607 
1608 	kfree(multi);
1609 	if (NULL == block_ctx_out->dev) {
1610 		ret = -ENXIO;
1611 		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1612 	}
1613 
1614 	return ret;
1615 }
1616 
1617 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1618 				  u32 len, struct block_device *bdev,
1619 				  struct btrfsic_block_data_ctx *block_ctx_out)
1620 {
1621 	block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1622 	block_ctx_out->dev_bytenr = bytenr;
1623 	block_ctx_out->start = bytenr;
1624 	block_ctx_out->len = len;
1625 	block_ctx_out->datav = NULL;
1626 	block_ctx_out->pagev = NULL;
1627 	block_ctx_out->mem_to_free = NULL;
1628 	if (NULL != block_ctx_out->dev) {
1629 		return 0;
1630 	} else {
1631 		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1632 		return -ENXIO;
1633 	}
1634 }
1635 
1636 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1637 {
1638 	if (block_ctx->mem_to_free) {
1639 		unsigned int num_pages;
1640 
1641 		BUG_ON(!block_ctx->datav);
1642 		BUG_ON(!block_ctx->pagev);
1643 		num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1644 			    PAGE_CACHE_SHIFT;
1645 		while (num_pages > 0) {
1646 			num_pages--;
1647 			if (block_ctx->datav[num_pages]) {
1648 				kunmap(block_ctx->pagev[num_pages]);
1649 				block_ctx->datav[num_pages] = NULL;
1650 			}
1651 			if (block_ctx->pagev[num_pages]) {
1652 				__free_page(block_ctx->pagev[num_pages]);
1653 				block_ctx->pagev[num_pages] = NULL;
1654 			}
1655 		}
1656 
1657 		kfree(block_ctx->mem_to_free);
1658 		block_ctx->mem_to_free = NULL;
1659 		block_ctx->pagev = NULL;
1660 		block_ctx->datav = NULL;
1661 	}
1662 }
1663 
1664 static int btrfsic_read_block(struct btrfsic_state *state,
1665 			      struct btrfsic_block_data_ctx *block_ctx)
1666 {
1667 	unsigned int num_pages;
1668 	unsigned int i;
1669 	u64 dev_bytenr;
1670 	int ret;
1671 
1672 	BUG_ON(block_ctx->datav);
1673 	BUG_ON(block_ctx->pagev);
1674 	BUG_ON(block_ctx->mem_to_free);
1675 	if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1676 		printk(KERN_INFO
1677 		       "btrfsic: read_block() with unaligned bytenr %llu\n",
1678 		       (unsigned long long)block_ctx->dev_bytenr);
1679 		return -1;
1680 	}
1681 
1682 	num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1683 		    PAGE_CACHE_SHIFT;
1684 	block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1685 					  sizeof(*block_ctx->pagev)) *
1686 					 num_pages, GFP_NOFS);
1687 	if (!block_ctx->mem_to_free)
1688 		return -1;
1689 	block_ctx->datav = block_ctx->mem_to_free;
1690 	block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1691 	for (i = 0; i < num_pages; i++) {
1692 		block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1693 		if (!block_ctx->pagev[i])
1694 			return -1;
1695 	}
1696 
1697 	dev_bytenr = block_ctx->dev_bytenr;
1698 	for (i = 0; i < num_pages;) {
1699 		struct bio *bio;
1700 		unsigned int j;
1701 		DECLARE_COMPLETION_ONSTACK(complete);
1702 
1703 		bio = btrfs_io_bio_alloc(GFP_NOFS, num_pages - i);
1704 		if (!bio) {
1705 			printk(KERN_INFO
1706 			       "btrfsic: bio_alloc() for %u pages failed!\n",
1707 			       num_pages - i);
1708 			return -1;
1709 		}
1710 		bio->bi_bdev = block_ctx->dev->bdev;
1711 		bio->bi_sector = dev_bytenr >> 9;
1712 		bio->bi_end_io = btrfsic_complete_bio_end_io;
1713 		bio->bi_private = &complete;
1714 
1715 		for (j = i; j < num_pages; j++) {
1716 			ret = bio_add_page(bio, block_ctx->pagev[j],
1717 					   PAGE_CACHE_SIZE, 0);
1718 			if (PAGE_CACHE_SIZE != ret)
1719 				break;
1720 		}
1721 		if (j == i) {
1722 			printk(KERN_INFO
1723 			       "btrfsic: error, failed to add a single page!\n");
1724 			return -1;
1725 		}
1726 		submit_bio(READ, bio);
1727 
1728 		/* this will also unplug the queue */
1729 		wait_for_completion(&complete);
1730 
1731 		if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
1732 			printk(KERN_INFO
1733 			       "btrfsic: read error at logical %llu dev %s!\n",
1734 			       block_ctx->start, block_ctx->dev->name);
1735 			bio_put(bio);
1736 			return -1;
1737 		}
1738 		bio_put(bio);
1739 		dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1740 		i = j;
1741 	}
1742 	for (i = 0; i < num_pages; i++) {
1743 		block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1744 		if (!block_ctx->datav[i]) {
1745 			printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1746 			       block_ctx->dev->name);
1747 			return -1;
1748 		}
1749 	}
1750 
1751 	return block_ctx->len;
1752 }
1753 
1754 static void btrfsic_complete_bio_end_io(struct bio *bio, int err)
1755 {
1756 	complete((struct completion *)bio->bi_private);
1757 }
1758 
1759 static void btrfsic_dump_database(struct btrfsic_state *state)
1760 {
1761 	struct list_head *elem_all;
1762 
1763 	BUG_ON(NULL == state);
1764 
1765 	printk(KERN_INFO "all_blocks_list:\n");
1766 	list_for_each(elem_all, &state->all_blocks_list) {
1767 		const struct btrfsic_block *const b_all =
1768 		    list_entry(elem_all, struct btrfsic_block,
1769 			       all_blocks_node);
1770 		struct list_head *elem_ref_to;
1771 		struct list_head *elem_ref_from;
1772 
1773 		printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1774 		       btrfsic_get_block_type(state, b_all),
1775 		       (unsigned long long)b_all->logical_bytenr,
1776 		       b_all->dev_state->name,
1777 		       (unsigned long long)b_all->dev_bytenr,
1778 		       b_all->mirror_num);
1779 
1780 		list_for_each(elem_ref_to, &b_all->ref_to_list) {
1781 			const struct btrfsic_block_link *const l =
1782 			    list_entry(elem_ref_to,
1783 				       struct btrfsic_block_link,
1784 				       node_ref_to);
1785 
1786 			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1787 			       " refers %u* to"
1788 			       " %c @%llu (%s/%llu/%d)\n",
1789 			       btrfsic_get_block_type(state, b_all),
1790 			       (unsigned long long)b_all->logical_bytenr,
1791 			       b_all->dev_state->name,
1792 			       (unsigned long long)b_all->dev_bytenr,
1793 			       b_all->mirror_num,
1794 			       l->ref_cnt,
1795 			       btrfsic_get_block_type(state, l->block_ref_to),
1796 			       (unsigned long long)
1797 			       l->block_ref_to->logical_bytenr,
1798 			       l->block_ref_to->dev_state->name,
1799 			       (unsigned long long)l->block_ref_to->dev_bytenr,
1800 			       l->block_ref_to->mirror_num);
1801 		}
1802 
1803 		list_for_each(elem_ref_from, &b_all->ref_from_list) {
1804 			const struct btrfsic_block_link *const l =
1805 			    list_entry(elem_ref_from,
1806 				       struct btrfsic_block_link,
1807 				       node_ref_from);
1808 
1809 			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1810 			       " is ref %u* from"
1811 			       " %c @%llu (%s/%llu/%d)\n",
1812 			       btrfsic_get_block_type(state, b_all),
1813 			       (unsigned long long)b_all->logical_bytenr,
1814 			       b_all->dev_state->name,
1815 			       (unsigned long long)b_all->dev_bytenr,
1816 			       b_all->mirror_num,
1817 			       l->ref_cnt,
1818 			       btrfsic_get_block_type(state, l->block_ref_from),
1819 			       (unsigned long long)
1820 			       l->block_ref_from->logical_bytenr,
1821 			       l->block_ref_from->dev_state->name,
1822 			       (unsigned long long)
1823 			       l->block_ref_from->dev_bytenr,
1824 			       l->block_ref_from->mirror_num);
1825 		}
1826 
1827 		printk(KERN_INFO "\n");
1828 	}
1829 }
1830 
1831 /*
1832  * Test whether the disk block contains a tree block (leaf or node)
1833  * (note that this test fails for the super block)
1834  */
1835 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1836 				     char **datav, unsigned int num_pages)
1837 {
1838 	struct btrfs_header *h;
1839 	u8 csum[BTRFS_CSUM_SIZE];
1840 	u32 crc = ~(u32)0;
1841 	unsigned int i;
1842 
1843 	if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1844 		return 1; /* not metadata */
1845 	num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1846 	h = (struct btrfs_header *)datav[0];
1847 
1848 	if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1849 		return 1;
1850 
1851 	for (i = 0; i < num_pages; i++) {
1852 		u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1853 		size_t sublen = i ? PAGE_CACHE_SIZE :
1854 				    (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1855 
1856 		crc = crc32c(crc, data, sublen);
1857 	}
1858 	btrfs_csum_final(crc, csum);
1859 	if (memcmp(csum, h->csum, state->csum_size))
1860 		return 1;
1861 
1862 	return 0; /* is metadata */
1863 }
1864 
1865 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1866 					  u64 dev_bytenr, char **mapped_datav,
1867 					  unsigned int num_pages,
1868 					  struct bio *bio, int *bio_is_patched,
1869 					  struct buffer_head *bh,
1870 					  int submit_bio_bh_rw)
1871 {
1872 	int is_metadata;
1873 	struct btrfsic_block *block;
1874 	struct btrfsic_block_data_ctx block_ctx;
1875 	int ret;
1876 	struct btrfsic_state *state = dev_state->state;
1877 	struct block_device *bdev = dev_state->bdev;
1878 	unsigned int processed_len;
1879 
1880 	if (NULL != bio_is_patched)
1881 		*bio_is_patched = 0;
1882 
1883 again:
1884 	if (num_pages == 0)
1885 		return;
1886 
1887 	processed_len = 0;
1888 	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1889 						      num_pages));
1890 
1891 	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1892 					       &state->block_hashtable);
1893 	if (NULL != block) {
1894 		u64 bytenr = 0;
1895 		struct list_head *elem_ref_to;
1896 		struct list_head *tmp_ref_to;
1897 
1898 		if (block->is_superblock) {
1899 			bytenr = le64_to_cpu(((struct btrfs_super_block *)
1900 					      mapped_datav[0])->bytenr);
1901 			if (num_pages * PAGE_CACHE_SIZE <
1902 			    BTRFS_SUPER_INFO_SIZE) {
1903 				printk(KERN_INFO
1904 				       "btrfsic: cannot work with too short bios!\n");
1905 				return;
1906 			}
1907 			is_metadata = 1;
1908 			BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1909 			processed_len = BTRFS_SUPER_INFO_SIZE;
1910 			if (state->print_mask &
1911 			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1912 				printk(KERN_INFO
1913 				       "[before new superblock is written]:\n");
1914 				btrfsic_dump_tree_sub(state, block, 0);
1915 			}
1916 		}
1917 		if (is_metadata) {
1918 			if (!block->is_superblock) {
1919 				if (num_pages * PAGE_CACHE_SIZE <
1920 				    state->metablock_size) {
1921 					printk(KERN_INFO
1922 					       "btrfsic: cannot work with too short bios!\n");
1923 					return;
1924 				}
1925 				processed_len = state->metablock_size;
1926 				bytenr = le64_to_cpu(((struct btrfs_header *)
1927 						      mapped_datav[0])->bytenr);
1928 				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1929 							       dev_state,
1930 							       dev_bytenr);
1931 			}
1932 			if (block->logical_bytenr != bytenr) {
1933 				printk(KERN_INFO
1934 				       "Written block @%llu (%s/%llu/%d)"
1935 				       " found in hash table, %c,"
1936 				       " bytenr mismatch"
1937 				       " (!= stored %llu).\n",
1938 				       (unsigned long long)bytenr,
1939 				       dev_state->name,
1940 				       (unsigned long long)dev_bytenr,
1941 				       block->mirror_num,
1942 				       btrfsic_get_block_type(state, block),
1943 				       (unsigned long long)
1944 				       block->logical_bytenr);
1945 				block->logical_bytenr = bytenr;
1946 			} else if (state->print_mask &
1947 				   BTRFSIC_PRINT_MASK_VERBOSE)
1948 				printk(KERN_INFO
1949 				       "Written block @%llu (%s/%llu/%d)"
1950 				       " found in hash table, %c.\n",
1951 				       (unsigned long long)bytenr,
1952 				       dev_state->name,
1953 				       (unsigned long long)dev_bytenr,
1954 				       block->mirror_num,
1955 				       btrfsic_get_block_type(state, block));
1956 		} else {
1957 			if (num_pages * PAGE_CACHE_SIZE <
1958 			    state->datablock_size) {
1959 				printk(KERN_INFO
1960 				       "btrfsic: cannot work with too short bios!\n");
1961 				return;
1962 			}
1963 			processed_len = state->datablock_size;
1964 			bytenr = block->logical_bytenr;
1965 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1966 				printk(KERN_INFO
1967 				       "Written block @%llu (%s/%llu/%d)"
1968 				       " found in hash table, %c.\n",
1969 				       (unsigned long long)bytenr,
1970 				       dev_state->name,
1971 				       (unsigned long long)dev_bytenr,
1972 				       block->mirror_num,
1973 				       btrfsic_get_block_type(state, block));
1974 		}
1975 
1976 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1977 			printk(KERN_INFO
1978 			       "ref_to_list: %cE, ref_from_list: %cE\n",
1979 			       list_empty(&block->ref_to_list) ? ' ' : '!',
1980 			       list_empty(&block->ref_from_list) ? ' ' : '!');
1981 		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1982 			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1983 			       " @%llu (%s/%llu/%d), old(gen=%llu,"
1984 			       " objectid=%llu, type=%d, offset=%llu),"
1985 			       " new(gen=%llu),"
1986 			       " which is referenced by most recent superblock"
1987 			       " (superblockgen=%llu)!\n",
1988 			       btrfsic_get_block_type(state, block),
1989 			       (unsigned long long)bytenr,
1990 			       dev_state->name,
1991 			       (unsigned long long)dev_bytenr,
1992 			       block->mirror_num,
1993 			       (unsigned long long)block->generation,
1994 			       (unsigned long long)
1995 			       le64_to_cpu(block->disk_key.objectid),
1996 			       block->disk_key.type,
1997 			       (unsigned long long)
1998 			       le64_to_cpu(block->disk_key.offset),
1999 			       (unsigned long long)
2000 			       le64_to_cpu(((struct btrfs_header *)
2001 					    mapped_datav[0])->generation),
2002 			       (unsigned long long)
2003 			       state->max_superblock_generation);
2004 			btrfsic_dump_tree(state);
2005 		}
2006 
2007 		if (!block->is_iodone && !block->never_written) {
2008 			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
2009 			       " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
2010 			       " which is not yet iodone!\n",
2011 			       btrfsic_get_block_type(state, block),
2012 			       (unsigned long long)bytenr,
2013 			       dev_state->name,
2014 			       (unsigned long long)dev_bytenr,
2015 			       block->mirror_num,
2016 			       (unsigned long long)block->generation,
2017 			       (unsigned long long)
2018 			       le64_to_cpu(((struct btrfs_header *)
2019 					    mapped_datav[0])->generation));
2020 			/* it would not be safe to go on */
2021 			btrfsic_dump_tree(state);
2022 			goto continue_loop;
2023 		}
2024 
2025 		/*
2026 		 * Clear all references of this block. Do not free
2027 		 * the block itself even if is not referenced anymore
2028 		 * because it still carries valueable information
2029 		 * like whether it was ever written and IO completed.
2030 		 */
2031 		list_for_each_safe(elem_ref_to, tmp_ref_to,
2032 				   &block->ref_to_list) {
2033 			struct btrfsic_block_link *const l =
2034 			    list_entry(elem_ref_to,
2035 				       struct btrfsic_block_link,
2036 				       node_ref_to);
2037 
2038 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2039 				btrfsic_print_rem_link(state, l);
2040 			l->ref_cnt--;
2041 			if (0 == l->ref_cnt) {
2042 				list_del(&l->node_ref_to);
2043 				list_del(&l->node_ref_from);
2044 				btrfsic_block_link_hashtable_remove(l);
2045 				btrfsic_block_link_free(l);
2046 			}
2047 		}
2048 
2049 		if (block->is_superblock)
2050 			ret = btrfsic_map_superblock(state, bytenr,
2051 						     processed_len,
2052 						     bdev, &block_ctx);
2053 		else
2054 			ret = btrfsic_map_block(state, bytenr, processed_len,
2055 						&block_ctx, 0);
2056 		if (ret) {
2057 			printk(KERN_INFO
2058 			       "btrfsic: btrfsic_map_block(root @%llu)"
2059 			       " failed!\n", (unsigned long long)bytenr);
2060 			goto continue_loop;
2061 		}
2062 		block_ctx.datav = mapped_datav;
2063 		/* the following is required in case of writes to mirrors,
2064 		 * use the same that was used for the lookup */
2065 		block_ctx.dev = dev_state;
2066 		block_ctx.dev_bytenr = dev_bytenr;
2067 
2068 		if (is_metadata || state->include_extent_data) {
2069 			block->never_written = 0;
2070 			block->iodone_w_error = 0;
2071 			if (NULL != bio) {
2072 				block->is_iodone = 0;
2073 				BUG_ON(NULL == bio_is_patched);
2074 				if (!*bio_is_patched) {
2075 					block->orig_bio_bh_private =
2076 					    bio->bi_private;
2077 					block->orig_bio_bh_end_io.bio =
2078 					    bio->bi_end_io;
2079 					block->next_in_same_bio = NULL;
2080 					bio->bi_private = block;
2081 					bio->bi_end_io = btrfsic_bio_end_io;
2082 					*bio_is_patched = 1;
2083 				} else {
2084 					struct btrfsic_block *chained_block =
2085 					    (struct btrfsic_block *)
2086 					    bio->bi_private;
2087 
2088 					BUG_ON(NULL == chained_block);
2089 					block->orig_bio_bh_private =
2090 					    chained_block->orig_bio_bh_private;
2091 					block->orig_bio_bh_end_io.bio =
2092 					    chained_block->orig_bio_bh_end_io.
2093 					    bio;
2094 					block->next_in_same_bio = chained_block;
2095 					bio->bi_private = block;
2096 				}
2097 			} else if (NULL != bh) {
2098 				block->is_iodone = 0;
2099 				block->orig_bio_bh_private = bh->b_private;
2100 				block->orig_bio_bh_end_io.bh = bh->b_end_io;
2101 				block->next_in_same_bio = NULL;
2102 				bh->b_private = block;
2103 				bh->b_end_io = btrfsic_bh_end_io;
2104 			} else {
2105 				block->is_iodone = 1;
2106 				block->orig_bio_bh_private = NULL;
2107 				block->orig_bio_bh_end_io.bio = NULL;
2108 				block->next_in_same_bio = NULL;
2109 			}
2110 		}
2111 
2112 		block->flush_gen = dev_state->last_flush_gen + 1;
2113 		block->submit_bio_bh_rw = submit_bio_bh_rw;
2114 		if (is_metadata) {
2115 			block->logical_bytenr = bytenr;
2116 			block->is_metadata = 1;
2117 			if (block->is_superblock) {
2118 				BUG_ON(PAGE_CACHE_SIZE !=
2119 				       BTRFS_SUPER_INFO_SIZE);
2120 				ret = btrfsic_process_written_superblock(
2121 						state,
2122 						block,
2123 						(struct btrfs_super_block *)
2124 						mapped_datav[0]);
2125 				if (state->print_mask &
2126 				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2127 					printk(KERN_INFO
2128 					"[after new superblock is written]:\n");
2129 					btrfsic_dump_tree_sub(state, block, 0);
2130 				}
2131 			} else {
2132 				block->mirror_num = 0;	/* unknown */
2133 				ret = btrfsic_process_metablock(
2134 						state,
2135 						block,
2136 						&block_ctx,
2137 						0, 0);
2138 			}
2139 			if (ret)
2140 				printk(KERN_INFO
2141 				       "btrfsic: btrfsic_process_metablock"
2142 				       "(root @%llu) failed!\n",
2143 				       (unsigned long long)dev_bytenr);
2144 		} else {
2145 			block->is_metadata = 0;
2146 			block->mirror_num = 0;	/* unknown */
2147 			block->generation = BTRFSIC_GENERATION_UNKNOWN;
2148 			if (!state->include_extent_data
2149 			    && list_empty(&block->ref_from_list)) {
2150 				/*
2151 				 * disk block is overwritten with extent
2152 				 * data (not meta data) and we are configured
2153 				 * to not include extent data: take the
2154 				 * chance and free the block's memory
2155 				 */
2156 				btrfsic_block_hashtable_remove(block);
2157 				list_del(&block->all_blocks_node);
2158 				btrfsic_block_free(block);
2159 			}
2160 		}
2161 		btrfsic_release_block_ctx(&block_ctx);
2162 	} else {
2163 		/* block has not been found in hash table */
2164 		u64 bytenr;
2165 
2166 		if (!is_metadata) {
2167 			processed_len = state->datablock_size;
2168 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2169 				printk(KERN_INFO "Written block (%s/%llu/?)"
2170 				       " !found in hash table, D.\n",
2171 				       dev_state->name,
2172 				       (unsigned long long)dev_bytenr);
2173 			if (!state->include_extent_data) {
2174 				/* ignore that written D block */
2175 				goto continue_loop;
2176 			}
2177 
2178 			/* this is getting ugly for the
2179 			 * include_extent_data case... */
2180 			bytenr = 0;	/* unknown */
2181 			block_ctx.start = bytenr;
2182 			block_ctx.len = processed_len;
2183 			block_ctx.mem_to_free = NULL;
2184 			block_ctx.pagev = NULL;
2185 		} else {
2186 			processed_len = state->metablock_size;
2187 			bytenr = le64_to_cpu(((struct btrfs_header *)
2188 					      mapped_datav[0])->bytenr);
2189 			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2190 						       dev_bytenr);
2191 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2192 				printk(KERN_INFO
2193 				       "Written block @%llu (%s/%llu/?)"
2194 				       " !found in hash table, M.\n",
2195 				       (unsigned long long)bytenr,
2196 				       dev_state->name,
2197 				       (unsigned long long)dev_bytenr);
2198 
2199 			ret = btrfsic_map_block(state, bytenr, processed_len,
2200 						&block_ctx, 0);
2201 			if (ret) {
2202 				printk(KERN_INFO
2203 				       "btrfsic: btrfsic_map_block(root @%llu)"
2204 				       " failed!\n",
2205 				       (unsigned long long)dev_bytenr);
2206 				goto continue_loop;
2207 			}
2208 		}
2209 		block_ctx.datav = mapped_datav;
2210 		/* the following is required in case of writes to mirrors,
2211 		 * use the same that was used for the lookup */
2212 		block_ctx.dev = dev_state;
2213 		block_ctx.dev_bytenr = dev_bytenr;
2214 
2215 		block = btrfsic_block_alloc();
2216 		if (NULL == block) {
2217 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2218 			btrfsic_release_block_ctx(&block_ctx);
2219 			goto continue_loop;
2220 		}
2221 		block->dev_state = dev_state;
2222 		block->dev_bytenr = dev_bytenr;
2223 		block->logical_bytenr = bytenr;
2224 		block->is_metadata = is_metadata;
2225 		block->never_written = 0;
2226 		block->iodone_w_error = 0;
2227 		block->mirror_num = 0;	/* unknown */
2228 		block->flush_gen = dev_state->last_flush_gen + 1;
2229 		block->submit_bio_bh_rw = submit_bio_bh_rw;
2230 		if (NULL != bio) {
2231 			block->is_iodone = 0;
2232 			BUG_ON(NULL == bio_is_patched);
2233 			if (!*bio_is_patched) {
2234 				block->orig_bio_bh_private = bio->bi_private;
2235 				block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2236 				block->next_in_same_bio = NULL;
2237 				bio->bi_private = block;
2238 				bio->bi_end_io = btrfsic_bio_end_io;
2239 				*bio_is_patched = 1;
2240 			} else {
2241 				struct btrfsic_block *chained_block =
2242 				    (struct btrfsic_block *)
2243 				    bio->bi_private;
2244 
2245 				BUG_ON(NULL == chained_block);
2246 				block->orig_bio_bh_private =
2247 				    chained_block->orig_bio_bh_private;
2248 				block->orig_bio_bh_end_io.bio =
2249 				    chained_block->orig_bio_bh_end_io.bio;
2250 				block->next_in_same_bio = chained_block;
2251 				bio->bi_private = block;
2252 			}
2253 		} else if (NULL != bh) {
2254 			block->is_iodone = 0;
2255 			block->orig_bio_bh_private = bh->b_private;
2256 			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2257 			block->next_in_same_bio = NULL;
2258 			bh->b_private = block;
2259 			bh->b_end_io = btrfsic_bh_end_io;
2260 		} else {
2261 			block->is_iodone = 1;
2262 			block->orig_bio_bh_private = NULL;
2263 			block->orig_bio_bh_end_io.bio = NULL;
2264 			block->next_in_same_bio = NULL;
2265 		}
2266 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2267 			printk(KERN_INFO
2268 			       "New written %c-block @%llu (%s/%llu/%d)\n",
2269 			       is_metadata ? 'M' : 'D',
2270 			       (unsigned long long)block->logical_bytenr,
2271 			       block->dev_state->name,
2272 			       (unsigned long long)block->dev_bytenr,
2273 			       block->mirror_num);
2274 		list_add(&block->all_blocks_node, &state->all_blocks_list);
2275 		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2276 
2277 		if (is_metadata) {
2278 			ret = btrfsic_process_metablock(state, block,
2279 							&block_ctx, 0, 0);
2280 			if (ret)
2281 				printk(KERN_INFO
2282 				       "btrfsic: process_metablock(root @%llu)"
2283 				       " failed!\n",
2284 				       (unsigned long long)dev_bytenr);
2285 		}
2286 		btrfsic_release_block_ctx(&block_ctx);
2287 	}
2288 
2289 continue_loop:
2290 	BUG_ON(!processed_len);
2291 	dev_bytenr += processed_len;
2292 	mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2293 	num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2294 	goto again;
2295 }
2296 
2297 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2298 {
2299 	struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2300 	int iodone_w_error;
2301 
2302 	/* mutex is not held! This is not save if IO is not yet completed
2303 	 * on umount */
2304 	iodone_w_error = 0;
2305 	if (bio_error_status)
2306 		iodone_w_error = 1;
2307 
2308 	BUG_ON(NULL == block);
2309 	bp->bi_private = block->orig_bio_bh_private;
2310 	bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2311 
2312 	do {
2313 		struct btrfsic_block *next_block;
2314 		struct btrfsic_dev_state *const dev_state = block->dev_state;
2315 
2316 		if ((dev_state->state->print_mask &
2317 		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2318 			printk(KERN_INFO
2319 			       "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2320 			       bio_error_status,
2321 			       btrfsic_get_block_type(dev_state->state, block),
2322 			       (unsigned long long)block->logical_bytenr,
2323 			       dev_state->name,
2324 			       (unsigned long long)block->dev_bytenr,
2325 			       block->mirror_num);
2326 		next_block = block->next_in_same_bio;
2327 		block->iodone_w_error = iodone_w_error;
2328 		if (block->submit_bio_bh_rw & REQ_FLUSH) {
2329 			dev_state->last_flush_gen++;
2330 			if ((dev_state->state->print_mask &
2331 			     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2332 				printk(KERN_INFO
2333 				       "bio_end_io() new %s flush_gen=%llu\n",
2334 				       dev_state->name,
2335 				       (unsigned long long)
2336 				       dev_state->last_flush_gen);
2337 		}
2338 		if (block->submit_bio_bh_rw & REQ_FUA)
2339 			block->flush_gen = 0; /* FUA completed means block is
2340 					       * on disk */
2341 		block->is_iodone = 1; /* for FLUSH, this releases the block */
2342 		block = next_block;
2343 	} while (NULL != block);
2344 
2345 	bp->bi_end_io(bp, bio_error_status);
2346 }
2347 
2348 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2349 {
2350 	struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2351 	int iodone_w_error = !uptodate;
2352 	struct btrfsic_dev_state *dev_state;
2353 
2354 	BUG_ON(NULL == block);
2355 	dev_state = block->dev_state;
2356 	if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2357 		printk(KERN_INFO
2358 		       "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2359 		       iodone_w_error,
2360 		       btrfsic_get_block_type(dev_state->state, block),
2361 		       (unsigned long long)block->logical_bytenr,
2362 		       block->dev_state->name,
2363 		       (unsigned long long)block->dev_bytenr,
2364 		       block->mirror_num);
2365 
2366 	block->iodone_w_error = iodone_w_error;
2367 	if (block->submit_bio_bh_rw & REQ_FLUSH) {
2368 		dev_state->last_flush_gen++;
2369 		if ((dev_state->state->print_mask &
2370 		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2371 			printk(KERN_INFO
2372 			       "bh_end_io() new %s flush_gen=%llu\n",
2373 			       dev_state->name,
2374 			       (unsigned long long)dev_state->last_flush_gen);
2375 	}
2376 	if (block->submit_bio_bh_rw & REQ_FUA)
2377 		block->flush_gen = 0; /* FUA completed means block is on disk */
2378 
2379 	bh->b_private = block->orig_bio_bh_private;
2380 	bh->b_end_io = block->orig_bio_bh_end_io.bh;
2381 	block->is_iodone = 1; /* for FLUSH, this releases the block */
2382 	bh->b_end_io(bh, uptodate);
2383 }
2384 
2385 static int btrfsic_process_written_superblock(
2386 		struct btrfsic_state *state,
2387 		struct btrfsic_block *const superblock,
2388 		struct btrfs_super_block *const super_hdr)
2389 {
2390 	int pass;
2391 
2392 	superblock->generation = btrfs_super_generation(super_hdr);
2393 	if (!(superblock->generation > state->max_superblock_generation ||
2394 	      0 == state->max_superblock_generation)) {
2395 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2396 			printk(KERN_INFO
2397 			       "btrfsic: superblock @%llu (%s/%llu/%d)"
2398 			       " with old gen %llu <= %llu\n",
2399 			       (unsigned long long)superblock->logical_bytenr,
2400 			       superblock->dev_state->name,
2401 			       (unsigned long long)superblock->dev_bytenr,
2402 			       superblock->mirror_num,
2403 			       (unsigned long long)
2404 			       btrfs_super_generation(super_hdr),
2405 			       (unsigned long long)
2406 			       state->max_superblock_generation);
2407 	} else {
2408 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2409 			printk(KERN_INFO
2410 			       "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2411 			       " with new gen %llu > %llu\n",
2412 			       (unsigned long long)superblock->logical_bytenr,
2413 			       superblock->dev_state->name,
2414 			       (unsigned long long)superblock->dev_bytenr,
2415 			       superblock->mirror_num,
2416 			       (unsigned long long)
2417 			       btrfs_super_generation(super_hdr),
2418 			       (unsigned long long)
2419 			       state->max_superblock_generation);
2420 
2421 		state->max_superblock_generation =
2422 		    btrfs_super_generation(super_hdr);
2423 		state->latest_superblock = superblock;
2424 	}
2425 
2426 	for (pass = 0; pass < 3; pass++) {
2427 		int ret;
2428 		u64 next_bytenr;
2429 		struct btrfsic_block *next_block;
2430 		struct btrfsic_block_data_ctx tmp_next_block_ctx;
2431 		struct btrfsic_block_link *l;
2432 		int num_copies;
2433 		int mirror_num;
2434 		const char *additional_string = NULL;
2435 		struct btrfs_disk_key tmp_disk_key;
2436 
2437 		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
2438 		tmp_disk_key.offset = 0;
2439 
2440 		switch (pass) {
2441 		case 0:
2442 			tmp_disk_key.objectid =
2443 			    cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
2444 			additional_string = "root ";
2445 			next_bytenr = btrfs_super_root(super_hdr);
2446 			if (state->print_mask &
2447 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2448 				printk(KERN_INFO "root@%llu\n",
2449 				       (unsigned long long)next_bytenr);
2450 			break;
2451 		case 1:
2452 			tmp_disk_key.objectid =
2453 			    cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
2454 			additional_string = "chunk ";
2455 			next_bytenr = btrfs_super_chunk_root(super_hdr);
2456 			if (state->print_mask &
2457 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2458 				printk(KERN_INFO "chunk@%llu\n",
2459 				       (unsigned long long)next_bytenr);
2460 			break;
2461 		case 2:
2462 			tmp_disk_key.objectid =
2463 			    cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
2464 			additional_string = "log ";
2465 			next_bytenr = btrfs_super_log_root(super_hdr);
2466 			if (0 == next_bytenr)
2467 				continue;
2468 			if (state->print_mask &
2469 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2470 				printk(KERN_INFO "log@%llu\n",
2471 				       (unsigned long long)next_bytenr);
2472 			break;
2473 		}
2474 
2475 		num_copies =
2476 		    btrfs_num_copies(state->root->fs_info,
2477 				     next_bytenr, BTRFS_SUPER_INFO_SIZE);
2478 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2479 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2480 			       (unsigned long long)next_bytenr, num_copies);
2481 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2482 			int was_created;
2483 
2484 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2485 				printk(KERN_INFO
2486 				       "btrfsic_process_written_superblock("
2487 				       "mirror_num=%d)\n", mirror_num);
2488 			ret = btrfsic_map_block(state, next_bytenr,
2489 						BTRFS_SUPER_INFO_SIZE,
2490 						&tmp_next_block_ctx,
2491 						mirror_num);
2492 			if (ret) {
2493 				printk(KERN_INFO
2494 				       "btrfsic: btrfsic_map_block(@%llu,"
2495 				       " mirror=%d) failed!\n",
2496 				       (unsigned long long)next_bytenr,
2497 				       mirror_num);
2498 				return -1;
2499 			}
2500 
2501 			next_block = btrfsic_block_lookup_or_add(
2502 					state,
2503 					&tmp_next_block_ctx,
2504 					additional_string,
2505 					1, 0, 1,
2506 					mirror_num,
2507 					&was_created);
2508 			if (NULL == next_block) {
2509 				printk(KERN_INFO
2510 				       "btrfsic: error, kmalloc failed!\n");
2511 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
2512 				return -1;
2513 			}
2514 
2515 			next_block->disk_key = tmp_disk_key;
2516 			if (was_created)
2517 				next_block->generation =
2518 				    BTRFSIC_GENERATION_UNKNOWN;
2519 			l = btrfsic_block_link_lookup_or_add(
2520 					state,
2521 					&tmp_next_block_ctx,
2522 					next_block,
2523 					superblock,
2524 					BTRFSIC_GENERATION_UNKNOWN);
2525 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
2526 			if (NULL == l)
2527 				return -1;
2528 		}
2529 	}
2530 
2531 	if (-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)) {
2532 		WARN_ON(1);
2533 		btrfsic_dump_tree(state);
2534 	}
2535 
2536 	return 0;
2537 }
2538 
2539 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2540 					struct btrfsic_block *const block,
2541 					int recursion_level)
2542 {
2543 	struct list_head *elem_ref_to;
2544 	int ret = 0;
2545 
2546 	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2547 		/*
2548 		 * Note that this situation can happen and does not
2549 		 * indicate an error in regular cases. It happens
2550 		 * when disk blocks are freed and later reused.
2551 		 * The check-integrity module is not aware of any
2552 		 * block free operations, it just recognizes block
2553 		 * write operations. Therefore it keeps the linkage
2554 		 * information for a block until a block is
2555 		 * rewritten. This can temporarily cause incorrect
2556 		 * and even circular linkage informations. This
2557 		 * causes no harm unless such blocks are referenced
2558 		 * by the most recent super block.
2559 		 */
2560 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2561 			printk(KERN_INFO
2562 			       "btrfsic: abort cyclic linkage (case 1).\n");
2563 
2564 		return ret;
2565 	}
2566 
2567 	/*
2568 	 * This algorithm is recursive because the amount of used stack
2569 	 * space is very small and the max recursion depth is limited.
2570 	 */
2571 	list_for_each(elem_ref_to, &block->ref_to_list) {
2572 		const struct btrfsic_block_link *const l =
2573 		    list_entry(elem_ref_to, struct btrfsic_block_link,
2574 			       node_ref_to);
2575 
2576 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2577 			printk(KERN_INFO
2578 			       "rl=%d, %c @%llu (%s/%llu/%d)"
2579 			       " %u* refers to %c @%llu (%s/%llu/%d)\n",
2580 			       recursion_level,
2581 			       btrfsic_get_block_type(state, block),
2582 			       (unsigned long long)block->logical_bytenr,
2583 			       block->dev_state->name,
2584 			       (unsigned long long)block->dev_bytenr,
2585 			       block->mirror_num,
2586 			       l->ref_cnt,
2587 			       btrfsic_get_block_type(state, l->block_ref_to),
2588 			       (unsigned long long)
2589 			       l->block_ref_to->logical_bytenr,
2590 			       l->block_ref_to->dev_state->name,
2591 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2592 			       l->block_ref_to->mirror_num);
2593 		if (l->block_ref_to->never_written) {
2594 			printk(KERN_INFO "btrfs: attempt to write superblock"
2595 			       " which references block %c @%llu (%s/%llu/%d)"
2596 			       " which is never written!\n",
2597 			       btrfsic_get_block_type(state, l->block_ref_to),
2598 			       (unsigned long long)
2599 			       l->block_ref_to->logical_bytenr,
2600 			       l->block_ref_to->dev_state->name,
2601 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2602 			       l->block_ref_to->mirror_num);
2603 			ret = -1;
2604 		} else if (!l->block_ref_to->is_iodone) {
2605 			printk(KERN_INFO "btrfs: attempt to write superblock"
2606 			       " which references block %c @%llu (%s/%llu/%d)"
2607 			       " which is not yet iodone!\n",
2608 			       btrfsic_get_block_type(state, l->block_ref_to),
2609 			       (unsigned long long)
2610 			       l->block_ref_to->logical_bytenr,
2611 			       l->block_ref_to->dev_state->name,
2612 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2613 			       l->block_ref_to->mirror_num);
2614 			ret = -1;
2615 		} else if (l->block_ref_to->iodone_w_error) {
2616 			printk(KERN_INFO "btrfs: attempt to write superblock"
2617 			       " which references block %c @%llu (%s/%llu/%d)"
2618 			       " which has write error!\n",
2619 			       btrfsic_get_block_type(state, l->block_ref_to),
2620 			       (unsigned long long)
2621 			       l->block_ref_to->logical_bytenr,
2622 			       l->block_ref_to->dev_state->name,
2623 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2624 			       l->block_ref_to->mirror_num);
2625 			ret = -1;
2626 		} else if (l->parent_generation !=
2627 			   l->block_ref_to->generation &&
2628 			   BTRFSIC_GENERATION_UNKNOWN !=
2629 			   l->parent_generation &&
2630 			   BTRFSIC_GENERATION_UNKNOWN !=
2631 			   l->block_ref_to->generation) {
2632 			printk(KERN_INFO "btrfs: attempt to write superblock"
2633 			       " which references block %c @%llu (%s/%llu/%d)"
2634 			       " with generation %llu !="
2635 			       " parent generation %llu!\n",
2636 			       btrfsic_get_block_type(state, l->block_ref_to),
2637 			       (unsigned long long)
2638 			       l->block_ref_to->logical_bytenr,
2639 			       l->block_ref_to->dev_state->name,
2640 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2641 			       l->block_ref_to->mirror_num,
2642 			       (unsigned long long)l->block_ref_to->generation,
2643 			       (unsigned long long)l->parent_generation);
2644 			ret = -1;
2645 		} else if (l->block_ref_to->flush_gen >
2646 			   l->block_ref_to->dev_state->last_flush_gen) {
2647 			printk(KERN_INFO "btrfs: attempt to write superblock"
2648 			       " which references block %c @%llu (%s/%llu/%d)"
2649 			       " which is not flushed out of disk's write cache"
2650 			       " (block flush_gen=%llu,"
2651 			       " dev->flush_gen=%llu)!\n",
2652 			       btrfsic_get_block_type(state, l->block_ref_to),
2653 			       (unsigned long long)
2654 			       l->block_ref_to->logical_bytenr,
2655 			       l->block_ref_to->dev_state->name,
2656 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2657 			       l->block_ref_to->mirror_num,
2658 			       (unsigned long long)block->flush_gen,
2659 			       (unsigned long long)
2660 			       l->block_ref_to->dev_state->last_flush_gen);
2661 			ret = -1;
2662 		} else if (-1 == btrfsic_check_all_ref_blocks(state,
2663 							      l->block_ref_to,
2664 							      recursion_level +
2665 							      1)) {
2666 			ret = -1;
2667 		}
2668 	}
2669 
2670 	return ret;
2671 }
2672 
2673 static int btrfsic_is_block_ref_by_superblock(
2674 		const struct btrfsic_state *state,
2675 		const struct btrfsic_block *block,
2676 		int recursion_level)
2677 {
2678 	struct list_head *elem_ref_from;
2679 
2680 	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2681 		/* refer to comment at "abort cyclic linkage (case 1)" */
2682 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2683 			printk(KERN_INFO
2684 			       "btrfsic: abort cyclic linkage (case 2).\n");
2685 
2686 		return 0;
2687 	}
2688 
2689 	/*
2690 	 * This algorithm is recursive because the amount of used stack space
2691 	 * is very small and the max recursion depth is limited.
2692 	 */
2693 	list_for_each(elem_ref_from, &block->ref_from_list) {
2694 		const struct btrfsic_block_link *const l =
2695 		    list_entry(elem_ref_from, struct btrfsic_block_link,
2696 			       node_ref_from);
2697 
2698 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2699 			printk(KERN_INFO
2700 			       "rl=%d, %c @%llu (%s/%llu/%d)"
2701 			       " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2702 			       recursion_level,
2703 			       btrfsic_get_block_type(state, block),
2704 			       (unsigned long long)block->logical_bytenr,
2705 			       block->dev_state->name,
2706 			       (unsigned long long)block->dev_bytenr,
2707 			       block->mirror_num,
2708 			       l->ref_cnt,
2709 			       btrfsic_get_block_type(state, l->block_ref_from),
2710 			       (unsigned long long)
2711 			       l->block_ref_from->logical_bytenr,
2712 			       l->block_ref_from->dev_state->name,
2713 			       (unsigned long long)
2714 			       l->block_ref_from->dev_bytenr,
2715 			       l->block_ref_from->mirror_num);
2716 		if (l->block_ref_from->is_superblock &&
2717 		    state->latest_superblock->dev_bytenr ==
2718 		    l->block_ref_from->dev_bytenr &&
2719 		    state->latest_superblock->dev_state->bdev ==
2720 		    l->block_ref_from->dev_state->bdev)
2721 			return 1;
2722 		else if (btrfsic_is_block_ref_by_superblock(state,
2723 							    l->block_ref_from,
2724 							    recursion_level +
2725 							    1))
2726 			return 1;
2727 	}
2728 
2729 	return 0;
2730 }
2731 
2732 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2733 				   const struct btrfsic_block_link *l)
2734 {
2735 	printk(KERN_INFO
2736 	       "Add %u* link from %c @%llu (%s/%llu/%d)"
2737 	       " to %c @%llu (%s/%llu/%d).\n",
2738 	       l->ref_cnt,
2739 	       btrfsic_get_block_type(state, l->block_ref_from),
2740 	       (unsigned long long)l->block_ref_from->logical_bytenr,
2741 	       l->block_ref_from->dev_state->name,
2742 	       (unsigned long long)l->block_ref_from->dev_bytenr,
2743 	       l->block_ref_from->mirror_num,
2744 	       btrfsic_get_block_type(state, l->block_ref_to),
2745 	       (unsigned long long)l->block_ref_to->logical_bytenr,
2746 	       l->block_ref_to->dev_state->name,
2747 	       (unsigned long long)l->block_ref_to->dev_bytenr,
2748 	       l->block_ref_to->mirror_num);
2749 }
2750 
2751 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2752 				   const struct btrfsic_block_link *l)
2753 {
2754 	printk(KERN_INFO
2755 	       "Rem %u* link from %c @%llu (%s/%llu/%d)"
2756 	       " to %c @%llu (%s/%llu/%d).\n",
2757 	       l->ref_cnt,
2758 	       btrfsic_get_block_type(state, l->block_ref_from),
2759 	       (unsigned long long)l->block_ref_from->logical_bytenr,
2760 	       l->block_ref_from->dev_state->name,
2761 	       (unsigned long long)l->block_ref_from->dev_bytenr,
2762 	       l->block_ref_from->mirror_num,
2763 	       btrfsic_get_block_type(state, l->block_ref_to),
2764 	       (unsigned long long)l->block_ref_to->logical_bytenr,
2765 	       l->block_ref_to->dev_state->name,
2766 	       (unsigned long long)l->block_ref_to->dev_bytenr,
2767 	       l->block_ref_to->mirror_num);
2768 }
2769 
2770 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2771 				   const struct btrfsic_block *block)
2772 {
2773 	if (block->is_superblock &&
2774 	    state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2775 	    state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2776 		return 'S';
2777 	else if (block->is_superblock)
2778 		return 's';
2779 	else if (block->is_metadata)
2780 		return 'M';
2781 	else
2782 		return 'D';
2783 }
2784 
2785 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2786 {
2787 	btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2788 }
2789 
2790 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2791 				  const struct btrfsic_block *block,
2792 				  int indent_level)
2793 {
2794 	struct list_head *elem_ref_to;
2795 	int indent_add;
2796 	static char buf[80];
2797 	int cursor_position;
2798 
2799 	/*
2800 	 * Should better fill an on-stack buffer with a complete line and
2801 	 * dump it at once when it is time to print a newline character.
2802 	 */
2803 
2804 	/*
2805 	 * This algorithm is recursive because the amount of used stack space
2806 	 * is very small and the max recursion depth is limited.
2807 	 */
2808 	indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2809 			     btrfsic_get_block_type(state, block),
2810 			     (unsigned long long)block->logical_bytenr,
2811 			     block->dev_state->name,
2812 			     (unsigned long long)block->dev_bytenr,
2813 			     block->mirror_num);
2814 	if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2815 		printk("[...]\n");
2816 		return;
2817 	}
2818 	printk(buf);
2819 	indent_level += indent_add;
2820 	if (list_empty(&block->ref_to_list)) {
2821 		printk("\n");
2822 		return;
2823 	}
2824 	if (block->mirror_num > 1 &&
2825 	    !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2826 		printk(" [...]\n");
2827 		return;
2828 	}
2829 
2830 	cursor_position = indent_level;
2831 	list_for_each(elem_ref_to, &block->ref_to_list) {
2832 		const struct btrfsic_block_link *const l =
2833 		    list_entry(elem_ref_to, struct btrfsic_block_link,
2834 			       node_ref_to);
2835 
2836 		while (cursor_position < indent_level) {
2837 			printk(" ");
2838 			cursor_position++;
2839 		}
2840 		if (l->ref_cnt > 1)
2841 			indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2842 		else
2843 			indent_add = sprintf(buf, " --> ");
2844 		if (indent_level + indent_add >
2845 		    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2846 			printk("[...]\n");
2847 			cursor_position = 0;
2848 			continue;
2849 		}
2850 
2851 		printk(buf);
2852 
2853 		btrfsic_dump_tree_sub(state, l->block_ref_to,
2854 				      indent_level + indent_add);
2855 		cursor_position = 0;
2856 	}
2857 }
2858 
2859 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2860 		struct btrfsic_state *state,
2861 		struct btrfsic_block_data_ctx *next_block_ctx,
2862 		struct btrfsic_block *next_block,
2863 		struct btrfsic_block *from_block,
2864 		u64 parent_generation)
2865 {
2866 	struct btrfsic_block_link *l;
2867 
2868 	l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2869 						next_block_ctx->dev_bytenr,
2870 						from_block->dev_state->bdev,
2871 						from_block->dev_bytenr,
2872 						&state->block_link_hashtable);
2873 	if (NULL == l) {
2874 		l = btrfsic_block_link_alloc();
2875 		if (NULL == l) {
2876 			printk(KERN_INFO
2877 			       "btrfsic: error, kmalloc" " failed!\n");
2878 			return NULL;
2879 		}
2880 
2881 		l->block_ref_to = next_block;
2882 		l->block_ref_from = from_block;
2883 		l->ref_cnt = 1;
2884 		l->parent_generation = parent_generation;
2885 
2886 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2887 			btrfsic_print_add_link(state, l);
2888 
2889 		list_add(&l->node_ref_to, &from_block->ref_to_list);
2890 		list_add(&l->node_ref_from, &next_block->ref_from_list);
2891 
2892 		btrfsic_block_link_hashtable_add(l,
2893 						 &state->block_link_hashtable);
2894 	} else {
2895 		l->ref_cnt++;
2896 		l->parent_generation = parent_generation;
2897 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2898 			btrfsic_print_add_link(state, l);
2899 	}
2900 
2901 	return l;
2902 }
2903 
2904 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2905 		struct btrfsic_state *state,
2906 		struct btrfsic_block_data_ctx *block_ctx,
2907 		const char *additional_string,
2908 		int is_metadata,
2909 		int is_iodone,
2910 		int never_written,
2911 		int mirror_num,
2912 		int *was_created)
2913 {
2914 	struct btrfsic_block *block;
2915 
2916 	block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2917 					       block_ctx->dev_bytenr,
2918 					       &state->block_hashtable);
2919 	if (NULL == block) {
2920 		struct btrfsic_dev_state *dev_state;
2921 
2922 		block = btrfsic_block_alloc();
2923 		if (NULL == block) {
2924 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2925 			return NULL;
2926 		}
2927 		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2928 		if (NULL == dev_state) {
2929 			printk(KERN_INFO
2930 			       "btrfsic: error, lookup dev_state failed!\n");
2931 			btrfsic_block_free(block);
2932 			return NULL;
2933 		}
2934 		block->dev_state = dev_state;
2935 		block->dev_bytenr = block_ctx->dev_bytenr;
2936 		block->logical_bytenr = block_ctx->start;
2937 		block->is_metadata = is_metadata;
2938 		block->is_iodone = is_iodone;
2939 		block->never_written = never_written;
2940 		block->mirror_num = mirror_num;
2941 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2942 			printk(KERN_INFO
2943 			       "New %s%c-block @%llu (%s/%llu/%d)\n",
2944 			       additional_string,
2945 			       btrfsic_get_block_type(state, block),
2946 			       (unsigned long long)block->logical_bytenr,
2947 			       dev_state->name,
2948 			       (unsigned long long)block->dev_bytenr,
2949 			       mirror_num);
2950 		list_add(&block->all_blocks_node, &state->all_blocks_list);
2951 		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2952 		if (NULL != was_created)
2953 			*was_created = 1;
2954 	} else {
2955 		if (NULL != was_created)
2956 			*was_created = 0;
2957 	}
2958 
2959 	return block;
2960 }
2961 
2962 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2963 					   u64 bytenr,
2964 					   struct btrfsic_dev_state *dev_state,
2965 					   u64 dev_bytenr)
2966 {
2967 	int num_copies;
2968 	int mirror_num;
2969 	int ret;
2970 	struct btrfsic_block_data_ctx block_ctx;
2971 	int match = 0;
2972 
2973 	num_copies = btrfs_num_copies(state->root->fs_info,
2974 				      bytenr, state->metablock_size);
2975 
2976 	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2977 		ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2978 					&block_ctx, mirror_num);
2979 		if (ret) {
2980 			printk(KERN_INFO "btrfsic:"
2981 			       " btrfsic_map_block(logical @%llu,"
2982 			       " mirror %d) failed!\n",
2983 			       (unsigned long long)bytenr, mirror_num);
2984 			continue;
2985 		}
2986 
2987 		if (dev_state->bdev == block_ctx.dev->bdev &&
2988 		    dev_bytenr == block_ctx.dev_bytenr) {
2989 			match++;
2990 			btrfsic_release_block_ctx(&block_ctx);
2991 			break;
2992 		}
2993 		btrfsic_release_block_ctx(&block_ctx);
2994 	}
2995 
2996 	if (!match) {
2997 		printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2998 		       " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2999 		       " phys_bytenr=%llu)!\n",
3000 		       (unsigned long long)bytenr, dev_state->name,
3001 		       (unsigned long long)dev_bytenr);
3002 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
3003 			ret = btrfsic_map_block(state, bytenr,
3004 						state->metablock_size,
3005 						&block_ctx, mirror_num);
3006 			if (ret)
3007 				continue;
3008 
3009 			printk(KERN_INFO "Read logical bytenr @%llu maps to"
3010 			       " (%s/%llu/%d)\n",
3011 			       (unsigned long long)bytenr,
3012 			       block_ctx.dev->name,
3013 			       (unsigned long long)block_ctx.dev_bytenr,
3014 			       mirror_num);
3015 		}
3016 		WARN_ON(1);
3017 	}
3018 }
3019 
3020 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
3021 		struct block_device *bdev)
3022 {
3023 	struct btrfsic_dev_state *ds;
3024 
3025 	ds = btrfsic_dev_state_hashtable_lookup(bdev,
3026 						&btrfsic_dev_state_hashtable);
3027 	return ds;
3028 }
3029 
3030 int btrfsic_submit_bh(int rw, struct buffer_head *bh)
3031 {
3032 	struct btrfsic_dev_state *dev_state;
3033 
3034 	if (!btrfsic_is_initialized)
3035 		return submit_bh(rw, bh);
3036 
3037 	mutex_lock(&btrfsic_mutex);
3038 	/* since btrfsic_submit_bh() might also be called before
3039 	 * btrfsic_mount(), this might return NULL */
3040 	dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
3041 
3042 	/* Only called to write the superblock (incl. FLUSH/FUA) */
3043 	if (NULL != dev_state &&
3044 	    (rw & WRITE) && bh->b_size > 0) {
3045 		u64 dev_bytenr;
3046 
3047 		dev_bytenr = 4096 * bh->b_blocknr;
3048 		if (dev_state->state->print_mask &
3049 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3050 			printk(KERN_INFO
3051 			       "submit_bh(rw=0x%x, blocknr=%lu (bytenr %llu),"
3052 			       " size=%lu, data=%p, bdev=%p)\n",
3053 			       rw, (unsigned long)bh->b_blocknr,
3054 			       (unsigned long long)dev_bytenr,
3055 			       (unsigned long)bh->b_size, bh->b_data,
3056 			       bh->b_bdev);
3057 		btrfsic_process_written_block(dev_state, dev_bytenr,
3058 					      &bh->b_data, 1, NULL,
3059 					      NULL, bh, rw);
3060 	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3061 		if (dev_state->state->print_mask &
3062 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3063 			printk(KERN_INFO
3064 			       "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
3065 			       rw, bh->b_bdev);
3066 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3067 			if ((dev_state->state->print_mask &
3068 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3069 			      BTRFSIC_PRINT_MASK_VERBOSE)))
3070 				printk(KERN_INFO
3071 				       "btrfsic_submit_bh(%s) with FLUSH"
3072 				       " but dummy block already in use"
3073 				       " (ignored)!\n",
3074 				       dev_state->name);
3075 		} else {
3076 			struct btrfsic_block *const block =
3077 				&dev_state->dummy_block_for_bio_bh_flush;
3078 
3079 			block->is_iodone = 0;
3080 			block->never_written = 0;
3081 			block->iodone_w_error = 0;
3082 			block->flush_gen = dev_state->last_flush_gen + 1;
3083 			block->submit_bio_bh_rw = rw;
3084 			block->orig_bio_bh_private = bh->b_private;
3085 			block->orig_bio_bh_end_io.bh = bh->b_end_io;
3086 			block->next_in_same_bio = NULL;
3087 			bh->b_private = block;
3088 			bh->b_end_io = btrfsic_bh_end_io;
3089 		}
3090 	}
3091 	mutex_unlock(&btrfsic_mutex);
3092 	return submit_bh(rw, bh);
3093 }
3094 
3095 void btrfsic_submit_bio(int rw, struct bio *bio)
3096 {
3097 	struct btrfsic_dev_state *dev_state;
3098 
3099 	if (!btrfsic_is_initialized) {
3100 		submit_bio(rw, bio);
3101 		return;
3102 	}
3103 
3104 	mutex_lock(&btrfsic_mutex);
3105 	/* since btrfsic_submit_bio() is also called before
3106 	 * btrfsic_mount(), this might return NULL */
3107 	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
3108 	if (NULL != dev_state &&
3109 	    (rw & WRITE) && NULL != bio->bi_io_vec) {
3110 		unsigned int i;
3111 		u64 dev_bytenr;
3112 		int bio_is_patched;
3113 		char **mapped_datav;
3114 
3115 		dev_bytenr = 512 * bio->bi_sector;
3116 		bio_is_patched = 0;
3117 		if (dev_state->state->print_mask &
3118 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3119 			printk(KERN_INFO
3120 			       "submit_bio(rw=0x%x, bi_vcnt=%u,"
3121 			       " bi_sector=%lu (bytenr %llu), bi_bdev=%p)\n",
3122 			       rw, bio->bi_vcnt, (unsigned long)bio->bi_sector,
3123 			       (unsigned long long)dev_bytenr,
3124 			       bio->bi_bdev);
3125 
3126 		mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
3127 				       GFP_NOFS);
3128 		if (!mapped_datav)
3129 			goto leave;
3130 		for (i = 0; i < bio->bi_vcnt; i++) {
3131 			BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3132 			mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3133 			if (!mapped_datav[i]) {
3134 				while (i > 0) {
3135 					i--;
3136 					kunmap(bio->bi_io_vec[i].bv_page);
3137 				}
3138 				kfree(mapped_datav);
3139 				goto leave;
3140 			}
3141 			if ((BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3142 			     BTRFSIC_PRINT_MASK_VERBOSE) ==
3143 			    (dev_state->state->print_mask &
3144 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3145 			      BTRFSIC_PRINT_MASK_VERBOSE)))
3146 				printk(KERN_INFO
3147 				       "#%u: page=%p, len=%u, offset=%u\n",
3148 				       i, bio->bi_io_vec[i].bv_page,
3149 				       bio->bi_io_vec[i].bv_len,
3150 				       bio->bi_io_vec[i].bv_offset);
3151 		}
3152 		btrfsic_process_written_block(dev_state, dev_bytenr,
3153 					      mapped_datav, bio->bi_vcnt,
3154 					      bio, &bio_is_patched,
3155 					      NULL, rw);
3156 		while (i > 0) {
3157 			i--;
3158 			kunmap(bio->bi_io_vec[i].bv_page);
3159 		}
3160 		kfree(mapped_datav);
3161 	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3162 		if (dev_state->state->print_mask &
3163 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3164 			printk(KERN_INFO
3165 			       "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3166 			       rw, bio->bi_bdev);
3167 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3168 			if ((dev_state->state->print_mask &
3169 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3170 			      BTRFSIC_PRINT_MASK_VERBOSE)))
3171 				printk(KERN_INFO
3172 				       "btrfsic_submit_bio(%s) with FLUSH"
3173 				       " but dummy block already in use"
3174 				       " (ignored)!\n",
3175 				       dev_state->name);
3176 		} else {
3177 			struct btrfsic_block *const block =
3178 				&dev_state->dummy_block_for_bio_bh_flush;
3179 
3180 			block->is_iodone = 0;
3181 			block->never_written = 0;
3182 			block->iodone_w_error = 0;
3183 			block->flush_gen = dev_state->last_flush_gen + 1;
3184 			block->submit_bio_bh_rw = rw;
3185 			block->orig_bio_bh_private = bio->bi_private;
3186 			block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3187 			block->next_in_same_bio = NULL;
3188 			bio->bi_private = block;
3189 			bio->bi_end_io = btrfsic_bio_end_io;
3190 		}
3191 	}
3192 leave:
3193 	mutex_unlock(&btrfsic_mutex);
3194 
3195 	submit_bio(rw, bio);
3196 }
3197 
3198 int btrfsic_mount(struct btrfs_root *root,
3199 		  struct btrfs_fs_devices *fs_devices,
3200 		  int including_extent_data, u32 print_mask)
3201 {
3202 	int ret;
3203 	struct btrfsic_state *state;
3204 	struct list_head *dev_head = &fs_devices->devices;
3205 	struct btrfs_device *device;
3206 
3207 	if (root->nodesize != root->leafsize) {
3208 		printk(KERN_INFO
3209 		       "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
3210 		       root->nodesize, root->leafsize);
3211 		return -1;
3212 	}
3213 	if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3214 		printk(KERN_INFO
3215 		       "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3216 		       root->nodesize, (unsigned long)PAGE_CACHE_SIZE);
3217 		return -1;
3218 	}
3219 	if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3220 		printk(KERN_INFO
3221 		       "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3222 		       root->leafsize, (unsigned long)PAGE_CACHE_SIZE);
3223 		return -1;
3224 	}
3225 	if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3226 		printk(KERN_INFO
3227 		       "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3228 		       root->sectorsize, (unsigned long)PAGE_CACHE_SIZE);
3229 		return -1;
3230 	}
3231 	state = kzalloc(sizeof(*state), GFP_NOFS);
3232 	if (NULL == state) {
3233 		printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
3234 		return -1;
3235 	}
3236 
3237 	if (!btrfsic_is_initialized) {
3238 		mutex_init(&btrfsic_mutex);
3239 		btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3240 		btrfsic_is_initialized = 1;
3241 	}
3242 	mutex_lock(&btrfsic_mutex);
3243 	state->root = root;
3244 	state->print_mask = print_mask;
3245 	state->include_extent_data = including_extent_data;
3246 	state->csum_size = 0;
3247 	state->metablock_size = root->nodesize;
3248 	state->datablock_size = root->sectorsize;
3249 	INIT_LIST_HEAD(&state->all_blocks_list);
3250 	btrfsic_block_hashtable_init(&state->block_hashtable);
3251 	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3252 	state->max_superblock_generation = 0;
3253 	state->latest_superblock = NULL;
3254 
3255 	list_for_each_entry(device, dev_head, dev_list) {
3256 		struct btrfsic_dev_state *ds;
3257 		char *p;
3258 
3259 		if (!device->bdev || !device->name)
3260 			continue;
3261 
3262 		ds = btrfsic_dev_state_alloc();
3263 		if (NULL == ds) {
3264 			printk(KERN_INFO
3265 			       "btrfs check-integrity: kmalloc() failed!\n");
3266 			mutex_unlock(&btrfsic_mutex);
3267 			return -1;
3268 		}
3269 		ds->bdev = device->bdev;
3270 		ds->state = state;
3271 		bdevname(ds->bdev, ds->name);
3272 		ds->name[BDEVNAME_SIZE - 1] = '\0';
3273 		for (p = ds->name; *p != '\0'; p++);
3274 		while (p > ds->name && *p != '/')
3275 			p--;
3276 		if (*p == '/')
3277 			p++;
3278 		strlcpy(ds->name, p, sizeof(ds->name));
3279 		btrfsic_dev_state_hashtable_add(ds,
3280 						&btrfsic_dev_state_hashtable);
3281 	}
3282 
3283 	ret = btrfsic_process_superblock(state, fs_devices);
3284 	if (0 != ret) {
3285 		mutex_unlock(&btrfsic_mutex);
3286 		btrfsic_unmount(root, fs_devices);
3287 		return ret;
3288 	}
3289 
3290 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3291 		btrfsic_dump_database(state);
3292 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3293 		btrfsic_dump_tree(state);
3294 
3295 	mutex_unlock(&btrfsic_mutex);
3296 	return 0;
3297 }
3298 
3299 void btrfsic_unmount(struct btrfs_root *root,
3300 		     struct btrfs_fs_devices *fs_devices)
3301 {
3302 	struct list_head *elem_all;
3303 	struct list_head *tmp_all;
3304 	struct btrfsic_state *state;
3305 	struct list_head *dev_head = &fs_devices->devices;
3306 	struct btrfs_device *device;
3307 
3308 	if (!btrfsic_is_initialized)
3309 		return;
3310 
3311 	mutex_lock(&btrfsic_mutex);
3312 
3313 	state = NULL;
3314 	list_for_each_entry(device, dev_head, dev_list) {
3315 		struct btrfsic_dev_state *ds;
3316 
3317 		if (!device->bdev || !device->name)
3318 			continue;
3319 
3320 		ds = btrfsic_dev_state_hashtable_lookup(
3321 				device->bdev,
3322 				&btrfsic_dev_state_hashtable);
3323 		if (NULL != ds) {
3324 			state = ds->state;
3325 			btrfsic_dev_state_hashtable_remove(ds);
3326 			btrfsic_dev_state_free(ds);
3327 		}
3328 	}
3329 
3330 	if (NULL == state) {
3331 		printk(KERN_INFO
3332 		       "btrfsic: error, cannot find state information"
3333 		       " on umount!\n");
3334 		mutex_unlock(&btrfsic_mutex);
3335 		return;
3336 	}
3337 
3338 	/*
3339 	 * Don't care about keeping the lists' state up to date,
3340 	 * just free all memory that was allocated dynamically.
3341 	 * Free the blocks and the block_links.
3342 	 */
3343 	list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3344 		struct btrfsic_block *const b_all =
3345 		    list_entry(elem_all, struct btrfsic_block,
3346 			       all_blocks_node);
3347 		struct list_head *elem_ref_to;
3348 		struct list_head *tmp_ref_to;
3349 
3350 		list_for_each_safe(elem_ref_to, tmp_ref_to,
3351 				   &b_all->ref_to_list) {
3352 			struct btrfsic_block_link *const l =
3353 			    list_entry(elem_ref_to,
3354 				       struct btrfsic_block_link,
3355 				       node_ref_to);
3356 
3357 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3358 				btrfsic_print_rem_link(state, l);
3359 
3360 			l->ref_cnt--;
3361 			if (0 == l->ref_cnt)
3362 				btrfsic_block_link_free(l);
3363 		}
3364 
3365 		if (b_all->is_iodone || b_all->never_written)
3366 			btrfsic_block_free(b_all);
3367 		else
3368 			printk(KERN_INFO "btrfs: attempt to free %c-block"
3369 			       " @%llu (%s/%llu/%d) on umount which is"
3370 			       " not yet iodone!\n",
3371 			       btrfsic_get_block_type(state, b_all),
3372 			       (unsigned long long)b_all->logical_bytenr,
3373 			       b_all->dev_state->name,
3374 			       (unsigned long long)b_all->dev_bytenr,
3375 			       b_all->mirror_num);
3376 	}
3377 
3378 	mutex_unlock(&btrfsic_mutex);
3379 
3380 	kfree(state);
3381 }
3382