xref: /openbmc/linux/fs/btrfs/check-integrity.c (revision 35a3621beb3e2face3e7954eaee20a8fa0043fac)
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 	    btrfs_super_magic(super_tmp) != 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 			btrfs_set_disk_key_objectid(&tmp_disk_key,
884 						    BTRFS_ROOT_TREE_OBJECTID);
885 			additional_string = "initial root ";
886 			next_bytenr = btrfs_super_root(super_tmp);
887 			break;
888 		case 1:
889 			btrfs_set_disk_key_objectid(&tmp_disk_key,
890 						    BTRFS_CHUNK_TREE_OBJECTID);
891 			additional_string = "initial chunk ";
892 			next_bytenr = btrfs_super_chunk_root(super_tmp);
893 			break;
894 		case 2:
895 			btrfs_set_disk_key_objectid(&tmp_disk_key,
896 						    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 = btrfs_stack_header_nritems(&leafhdr->header);
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 				       btrfs_stack_header_generation(
1017 					       &leafhdr->header),
1018 				       (unsigned long long)
1019 				       btrfs_stack_header_owner(
1020 					       &leafhdr->header));
1021 		}
1022 
1023 continue_with_current_leaf_stack_frame:
1024 		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1025 			sf->i++;
1026 			sf->num_copies = 0;
1027 		}
1028 
1029 		if (sf->i < sf->nr) {
1030 			struct btrfs_item disk_item;
1031 			u32 disk_item_offset =
1032 				(uintptr_t)(leafhdr->items + sf->i) -
1033 				(uintptr_t)leafhdr;
1034 			struct btrfs_disk_key *disk_key;
1035 			u8 type;
1036 			u32 item_offset;
1037 			u32 item_size;
1038 
1039 			if (disk_item_offset + sizeof(struct btrfs_item) >
1040 			    sf->block_ctx->len) {
1041 leaf_item_out_of_bounce_error:
1042 				printk(KERN_INFO
1043 				       "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1044 				       sf->block_ctx->start,
1045 				       sf->block_ctx->dev->name);
1046 				goto one_stack_frame_backwards;
1047 			}
1048 			btrfsic_read_from_block_data(sf->block_ctx,
1049 						     &disk_item,
1050 						     disk_item_offset,
1051 						     sizeof(struct btrfs_item));
1052 			item_offset = btrfs_stack_item_offset(&disk_item);
1053 			item_size = btrfs_stack_item_offset(&disk_item);
1054 			disk_key = &disk_item.key;
1055 			type = btrfs_disk_key_type(disk_key);
1056 
1057 			if (BTRFS_ROOT_ITEM_KEY == type) {
1058 				struct btrfs_root_item root_item;
1059 				u32 root_item_offset;
1060 				u64 next_bytenr;
1061 
1062 				root_item_offset = item_offset +
1063 					offsetof(struct btrfs_leaf, items);
1064 				if (root_item_offset + item_size >
1065 				    sf->block_ctx->len)
1066 					goto leaf_item_out_of_bounce_error;
1067 				btrfsic_read_from_block_data(
1068 					sf->block_ctx, &root_item,
1069 					root_item_offset,
1070 					item_size);
1071 				next_bytenr = btrfs_root_bytenr(&root_item);
1072 
1073 				sf->error =
1074 				    btrfsic_create_link_to_next_block(
1075 						state,
1076 						sf->block,
1077 						sf->block_ctx,
1078 						next_bytenr,
1079 						sf->limit_nesting,
1080 						&sf->next_block_ctx,
1081 						&sf->next_block,
1082 						force_iodone_flag,
1083 						&sf->num_copies,
1084 						&sf->mirror_num,
1085 						disk_key,
1086 						btrfs_root_generation(
1087 						&root_item));
1088 				if (sf->error)
1089 					goto one_stack_frame_backwards;
1090 
1091 				if (NULL != sf->next_block) {
1092 					struct btrfs_header *const next_hdr =
1093 					    (struct btrfs_header *)
1094 					    sf->next_block_ctx.datav[0];
1095 
1096 					next_stack =
1097 					    btrfsic_stack_frame_alloc();
1098 					if (NULL == next_stack) {
1099 						btrfsic_release_block_ctx(
1100 								&sf->
1101 								next_block_ctx);
1102 						goto one_stack_frame_backwards;
1103 					}
1104 
1105 					next_stack->i = -1;
1106 					next_stack->block = sf->next_block;
1107 					next_stack->block_ctx =
1108 					    &sf->next_block_ctx;
1109 					next_stack->next_block = NULL;
1110 					next_stack->hdr = next_hdr;
1111 					next_stack->limit_nesting =
1112 					    sf->limit_nesting - 1;
1113 					next_stack->prev = sf;
1114 					sf = next_stack;
1115 					goto continue_with_new_stack_frame;
1116 				}
1117 			} else if (BTRFS_EXTENT_DATA_KEY == type &&
1118 				   state->include_extent_data) {
1119 				sf->error = btrfsic_handle_extent_data(
1120 						state,
1121 						sf->block,
1122 						sf->block_ctx,
1123 						item_offset,
1124 						force_iodone_flag);
1125 				if (sf->error)
1126 					goto one_stack_frame_backwards;
1127 			}
1128 
1129 			goto continue_with_current_leaf_stack_frame;
1130 		}
1131 	} else {
1132 		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1133 
1134 		if (-1 == sf->i) {
1135 			sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1136 
1137 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1138 				printk(KERN_INFO "node %llu level %d items %d"
1139 				       " generation %llu owner %llu\n",
1140 				       (unsigned long long)
1141 				       sf->block_ctx->start,
1142 				       nodehdr->header.level, sf->nr,
1143 				       (unsigned long long)
1144 				       btrfs_stack_header_generation(
1145 				       &nodehdr->header),
1146 				       (unsigned long long)
1147 				       btrfs_stack_header_owner(
1148 				       &nodehdr->header));
1149 		}
1150 
1151 continue_with_current_node_stack_frame:
1152 		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1153 			sf->i++;
1154 			sf->num_copies = 0;
1155 		}
1156 
1157 		if (sf->i < sf->nr) {
1158 			struct btrfs_key_ptr key_ptr;
1159 			u32 key_ptr_offset;
1160 			u64 next_bytenr;
1161 
1162 			key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1163 					  (uintptr_t)nodehdr;
1164 			if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1165 			    sf->block_ctx->len) {
1166 				printk(KERN_INFO
1167 				       "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1168 				       sf->block_ctx->start,
1169 				       sf->block_ctx->dev->name);
1170 				goto one_stack_frame_backwards;
1171 			}
1172 			btrfsic_read_from_block_data(
1173 				sf->block_ctx, &key_ptr, key_ptr_offset,
1174 				sizeof(struct btrfs_key_ptr));
1175 			next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1176 
1177 			sf->error = btrfsic_create_link_to_next_block(
1178 					state,
1179 					sf->block,
1180 					sf->block_ctx,
1181 					next_bytenr,
1182 					sf->limit_nesting,
1183 					&sf->next_block_ctx,
1184 					&sf->next_block,
1185 					force_iodone_flag,
1186 					&sf->num_copies,
1187 					&sf->mirror_num,
1188 					&key_ptr.key,
1189 					btrfs_stack_key_generation(&key_ptr));
1190 			if (sf->error)
1191 				goto one_stack_frame_backwards;
1192 
1193 			if (NULL != sf->next_block) {
1194 				struct btrfs_header *const next_hdr =
1195 				    (struct btrfs_header *)
1196 				    sf->next_block_ctx.datav[0];
1197 
1198 				next_stack = btrfsic_stack_frame_alloc();
1199 				if (NULL == next_stack)
1200 					goto one_stack_frame_backwards;
1201 
1202 				next_stack->i = -1;
1203 				next_stack->block = sf->next_block;
1204 				next_stack->block_ctx = &sf->next_block_ctx;
1205 				next_stack->next_block = NULL;
1206 				next_stack->hdr = next_hdr;
1207 				next_stack->limit_nesting =
1208 				    sf->limit_nesting - 1;
1209 				next_stack->prev = sf;
1210 				sf = next_stack;
1211 				goto continue_with_new_stack_frame;
1212 			}
1213 
1214 			goto continue_with_current_node_stack_frame;
1215 		}
1216 	}
1217 
1218 one_stack_frame_backwards:
1219 	if (NULL != sf->prev) {
1220 		struct btrfsic_stack_frame *const prev = sf->prev;
1221 
1222 		/* the one for the initial block is freed in the caller */
1223 		btrfsic_release_block_ctx(sf->block_ctx);
1224 
1225 		if (sf->error) {
1226 			prev->error = sf->error;
1227 			btrfsic_stack_frame_free(sf);
1228 			sf = prev;
1229 			goto one_stack_frame_backwards;
1230 		}
1231 
1232 		btrfsic_stack_frame_free(sf);
1233 		sf = prev;
1234 		goto continue_with_new_stack_frame;
1235 	} else {
1236 		BUG_ON(&initial_stack_frame != sf);
1237 	}
1238 
1239 	return sf->error;
1240 }
1241 
1242 static void btrfsic_read_from_block_data(
1243 	struct btrfsic_block_data_ctx *block_ctx,
1244 	void *dstv, u32 offset, size_t len)
1245 {
1246 	size_t cur;
1247 	size_t offset_in_page;
1248 	char *kaddr;
1249 	char *dst = (char *)dstv;
1250 	size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1251 	unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1252 
1253 	WARN_ON(offset + len > block_ctx->len);
1254 	offset_in_page = (start_offset + offset) &
1255 			 ((unsigned long)PAGE_CACHE_SIZE - 1);
1256 
1257 	while (len > 0) {
1258 		cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1259 		BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
1260 			    PAGE_CACHE_SHIFT);
1261 		kaddr = block_ctx->datav[i];
1262 		memcpy(dst, kaddr + offset_in_page, cur);
1263 
1264 		dst += cur;
1265 		len -= cur;
1266 		offset_in_page = 0;
1267 		i++;
1268 	}
1269 }
1270 
1271 static int btrfsic_create_link_to_next_block(
1272 		struct btrfsic_state *state,
1273 		struct btrfsic_block *block,
1274 		struct btrfsic_block_data_ctx *block_ctx,
1275 		u64 next_bytenr,
1276 		int limit_nesting,
1277 		struct btrfsic_block_data_ctx *next_block_ctx,
1278 		struct btrfsic_block **next_blockp,
1279 		int force_iodone_flag,
1280 		int *num_copiesp, int *mirror_nump,
1281 		struct btrfs_disk_key *disk_key,
1282 		u64 parent_generation)
1283 {
1284 	struct btrfsic_block *next_block = NULL;
1285 	int ret;
1286 	struct btrfsic_block_link *l;
1287 	int did_alloc_block_link;
1288 	int block_was_created;
1289 
1290 	*next_blockp = NULL;
1291 	if (0 == *num_copiesp) {
1292 		*num_copiesp =
1293 		    btrfs_num_copies(state->root->fs_info,
1294 				     next_bytenr, state->metablock_size);
1295 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1296 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1297 			       (unsigned long long)next_bytenr, *num_copiesp);
1298 		*mirror_nump = 1;
1299 	}
1300 
1301 	if (*mirror_nump > *num_copiesp)
1302 		return 0;
1303 
1304 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1305 		printk(KERN_INFO
1306 		       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1307 		       *mirror_nump);
1308 	ret = btrfsic_map_block(state, next_bytenr,
1309 				state->metablock_size,
1310 				next_block_ctx, *mirror_nump);
1311 	if (ret) {
1312 		printk(KERN_INFO
1313 		       "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1314 		       (unsigned long long)next_bytenr, *mirror_nump);
1315 		btrfsic_release_block_ctx(next_block_ctx);
1316 		*next_blockp = NULL;
1317 		return -1;
1318 	}
1319 
1320 	next_block = btrfsic_block_lookup_or_add(state,
1321 						 next_block_ctx, "referenced ",
1322 						 1, force_iodone_flag,
1323 						 !force_iodone_flag,
1324 						 *mirror_nump,
1325 						 &block_was_created);
1326 	if (NULL == next_block) {
1327 		btrfsic_release_block_ctx(next_block_ctx);
1328 		*next_blockp = NULL;
1329 		return -1;
1330 	}
1331 	if (block_was_created) {
1332 		l = NULL;
1333 		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1334 	} else {
1335 		if (next_block->logical_bytenr != next_bytenr &&
1336 		    !(!next_block->is_metadata &&
1337 		      0 == next_block->logical_bytenr)) {
1338 			printk(KERN_INFO
1339 			       "Referenced block @%llu (%s/%llu/%d)"
1340 			       " found in hash table, %c,"
1341 			       " bytenr mismatch (!= stored %llu).\n",
1342 			       (unsigned long long)next_bytenr,
1343 			       next_block_ctx->dev->name,
1344 			       (unsigned long long)next_block_ctx->dev_bytenr,
1345 			       *mirror_nump,
1346 			       btrfsic_get_block_type(state, next_block),
1347 			       (unsigned long long)next_block->logical_bytenr);
1348 		} else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1349 			printk(KERN_INFO
1350 			       "Referenced block @%llu (%s/%llu/%d)"
1351 			       " found in hash table, %c.\n",
1352 			       (unsigned long long)next_bytenr,
1353 			       next_block_ctx->dev->name,
1354 			       (unsigned long long)next_block_ctx->dev_bytenr,
1355 			       *mirror_nump,
1356 			       btrfsic_get_block_type(state, next_block));
1357 		next_block->logical_bytenr = next_bytenr;
1358 
1359 		next_block->mirror_num = *mirror_nump;
1360 		l = btrfsic_block_link_hashtable_lookup(
1361 				next_block_ctx->dev->bdev,
1362 				next_block_ctx->dev_bytenr,
1363 				block_ctx->dev->bdev,
1364 				block_ctx->dev_bytenr,
1365 				&state->block_link_hashtable);
1366 	}
1367 
1368 	next_block->disk_key = *disk_key;
1369 	if (NULL == l) {
1370 		l = btrfsic_block_link_alloc();
1371 		if (NULL == l) {
1372 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1373 			btrfsic_release_block_ctx(next_block_ctx);
1374 			*next_blockp = NULL;
1375 			return -1;
1376 		}
1377 
1378 		did_alloc_block_link = 1;
1379 		l->block_ref_to = next_block;
1380 		l->block_ref_from = block;
1381 		l->ref_cnt = 1;
1382 		l->parent_generation = parent_generation;
1383 
1384 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1385 			btrfsic_print_add_link(state, l);
1386 
1387 		list_add(&l->node_ref_to, &block->ref_to_list);
1388 		list_add(&l->node_ref_from, &next_block->ref_from_list);
1389 
1390 		btrfsic_block_link_hashtable_add(l,
1391 						 &state->block_link_hashtable);
1392 	} else {
1393 		did_alloc_block_link = 0;
1394 		if (0 == limit_nesting) {
1395 			l->ref_cnt++;
1396 			l->parent_generation = parent_generation;
1397 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1398 				btrfsic_print_add_link(state, l);
1399 		}
1400 	}
1401 
1402 	if (limit_nesting > 0 && did_alloc_block_link) {
1403 		ret = btrfsic_read_block(state, next_block_ctx);
1404 		if (ret < (int)next_block_ctx->len) {
1405 			printk(KERN_INFO
1406 			       "btrfsic: read block @logical %llu failed!\n",
1407 			       (unsigned long long)next_bytenr);
1408 			btrfsic_release_block_ctx(next_block_ctx);
1409 			*next_blockp = NULL;
1410 			return -1;
1411 		}
1412 
1413 		*next_blockp = next_block;
1414 	} else {
1415 		*next_blockp = NULL;
1416 	}
1417 	(*mirror_nump)++;
1418 
1419 	return 0;
1420 }
1421 
1422 static int btrfsic_handle_extent_data(
1423 		struct btrfsic_state *state,
1424 		struct btrfsic_block *block,
1425 		struct btrfsic_block_data_ctx *block_ctx,
1426 		u32 item_offset, int force_iodone_flag)
1427 {
1428 	int ret;
1429 	struct btrfs_file_extent_item file_extent_item;
1430 	u64 file_extent_item_offset;
1431 	u64 next_bytenr;
1432 	u64 num_bytes;
1433 	u64 generation;
1434 	struct btrfsic_block_link *l;
1435 
1436 	file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1437 				  item_offset;
1438 	if (file_extent_item_offset +
1439 	    offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1440 	    block_ctx->len) {
1441 		printk(KERN_INFO
1442 		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1443 		       block_ctx->start, block_ctx->dev->name);
1444 		return -1;
1445 	}
1446 
1447 	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1448 		file_extent_item_offset,
1449 		offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1450 	if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1451 	    btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1452 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1453 			printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1454 			       file_extent_item.type,
1455 			       (unsigned long long)
1456 			       btrfs_stack_file_extent_disk_bytenr(
1457 			       &file_extent_item));
1458 		return 0;
1459 	}
1460 
1461 	if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1462 	    block_ctx->len) {
1463 		printk(KERN_INFO
1464 		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1465 		       block_ctx->start, block_ctx->dev->name);
1466 		return -1;
1467 	}
1468 	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1469 				     file_extent_item_offset,
1470 				     sizeof(struct btrfs_file_extent_item));
1471 	next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item) +
1472 		      btrfs_stack_file_extent_offset(&file_extent_item);
1473 	generation = btrfs_stack_file_extent_generation(&file_extent_item);
1474 	num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1475 	generation = btrfs_stack_file_extent_generation(&file_extent_item);
1476 
1477 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1478 		printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1479 		       " offset = %llu, num_bytes = %llu\n",
1480 		       file_extent_item.type,
1481 		       (unsigned long long)
1482 		       btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1483 		       (unsigned long long)
1484 		       btrfs_stack_file_extent_offset(&file_extent_item),
1485 		       (unsigned long long)num_bytes);
1486 	while (num_bytes > 0) {
1487 		u32 chunk_len;
1488 		int num_copies;
1489 		int mirror_num;
1490 
1491 		if (num_bytes > state->datablock_size)
1492 			chunk_len = state->datablock_size;
1493 		else
1494 			chunk_len = num_bytes;
1495 
1496 		num_copies =
1497 		    btrfs_num_copies(state->root->fs_info,
1498 				     next_bytenr, state->datablock_size);
1499 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1500 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1501 			       (unsigned long long)next_bytenr, num_copies);
1502 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1503 			struct btrfsic_block_data_ctx next_block_ctx;
1504 			struct btrfsic_block *next_block;
1505 			int block_was_created;
1506 
1507 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1508 				printk(KERN_INFO "btrfsic_handle_extent_data("
1509 				       "mirror_num=%d)\n", mirror_num);
1510 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1511 				printk(KERN_INFO
1512 				       "\tdisk_bytenr = %llu, num_bytes %u\n",
1513 				       (unsigned long long)next_bytenr,
1514 				       chunk_len);
1515 			ret = btrfsic_map_block(state, next_bytenr,
1516 						chunk_len, &next_block_ctx,
1517 						mirror_num);
1518 			if (ret) {
1519 				printk(KERN_INFO
1520 				       "btrfsic: btrfsic_map_block(@%llu,"
1521 				       " mirror=%d) failed!\n",
1522 				       (unsigned long long)next_bytenr,
1523 				       mirror_num);
1524 				return -1;
1525 			}
1526 
1527 			next_block = btrfsic_block_lookup_or_add(
1528 					state,
1529 					&next_block_ctx,
1530 					"referenced ",
1531 					0,
1532 					force_iodone_flag,
1533 					!force_iodone_flag,
1534 					mirror_num,
1535 					&block_was_created);
1536 			if (NULL == next_block) {
1537 				printk(KERN_INFO
1538 				       "btrfsic: error, kmalloc failed!\n");
1539 				btrfsic_release_block_ctx(&next_block_ctx);
1540 				return -1;
1541 			}
1542 			if (!block_was_created) {
1543 				if (next_block->logical_bytenr != next_bytenr &&
1544 				    !(!next_block->is_metadata &&
1545 				      0 == next_block->logical_bytenr)) {
1546 					printk(KERN_INFO
1547 					       "Referenced block"
1548 					       " @%llu (%s/%llu/%d)"
1549 					       " found in hash table, D,"
1550 					       " bytenr mismatch"
1551 					       " (!= stored %llu).\n",
1552 					       (unsigned long long)next_bytenr,
1553 					       next_block_ctx.dev->name,
1554 					       (unsigned long long)
1555 					       next_block_ctx.dev_bytenr,
1556 					       mirror_num,
1557 					       (unsigned long long)
1558 					       next_block->logical_bytenr);
1559 				}
1560 				next_block->logical_bytenr = next_bytenr;
1561 				next_block->mirror_num = mirror_num;
1562 			}
1563 
1564 			l = btrfsic_block_link_lookup_or_add(state,
1565 							     &next_block_ctx,
1566 							     next_block, block,
1567 							     generation);
1568 			btrfsic_release_block_ctx(&next_block_ctx);
1569 			if (NULL == l)
1570 				return -1;
1571 		}
1572 
1573 		next_bytenr += chunk_len;
1574 		num_bytes -= chunk_len;
1575 	}
1576 
1577 	return 0;
1578 }
1579 
1580 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1581 			     struct btrfsic_block_data_ctx *block_ctx_out,
1582 			     int mirror_num)
1583 {
1584 	int ret;
1585 	u64 length;
1586 	struct btrfs_bio *multi = NULL;
1587 	struct btrfs_device *device;
1588 
1589 	length = len;
1590 	ret = btrfs_map_block(state->root->fs_info, READ,
1591 			      bytenr, &length, &multi, mirror_num);
1592 
1593 	if (ret) {
1594 		block_ctx_out->start = 0;
1595 		block_ctx_out->dev_bytenr = 0;
1596 		block_ctx_out->len = 0;
1597 		block_ctx_out->dev = NULL;
1598 		block_ctx_out->datav = NULL;
1599 		block_ctx_out->pagev = NULL;
1600 		block_ctx_out->mem_to_free = NULL;
1601 
1602 		return ret;
1603 	}
1604 
1605 	device = multi->stripes[0].dev;
1606 	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1607 	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1608 	block_ctx_out->start = bytenr;
1609 	block_ctx_out->len = len;
1610 	block_ctx_out->datav = NULL;
1611 	block_ctx_out->pagev = NULL;
1612 	block_ctx_out->mem_to_free = NULL;
1613 
1614 	kfree(multi);
1615 	if (NULL == block_ctx_out->dev) {
1616 		ret = -ENXIO;
1617 		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1618 	}
1619 
1620 	return ret;
1621 }
1622 
1623 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1624 				  u32 len, struct block_device *bdev,
1625 				  struct btrfsic_block_data_ctx *block_ctx_out)
1626 {
1627 	block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1628 	block_ctx_out->dev_bytenr = bytenr;
1629 	block_ctx_out->start = bytenr;
1630 	block_ctx_out->len = len;
1631 	block_ctx_out->datav = NULL;
1632 	block_ctx_out->pagev = NULL;
1633 	block_ctx_out->mem_to_free = NULL;
1634 	if (NULL != block_ctx_out->dev) {
1635 		return 0;
1636 	} else {
1637 		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1638 		return -ENXIO;
1639 	}
1640 }
1641 
1642 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1643 {
1644 	if (block_ctx->mem_to_free) {
1645 		unsigned int num_pages;
1646 
1647 		BUG_ON(!block_ctx->datav);
1648 		BUG_ON(!block_ctx->pagev);
1649 		num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1650 			    PAGE_CACHE_SHIFT;
1651 		while (num_pages > 0) {
1652 			num_pages--;
1653 			if (block_ctx->datav[num_pages]) {
1654 				kunmap(block_ctx->pagev[num_pages]);
1655 				block_ctx->datav[num_pages] = NULL;
1656 			}
1657 			if (block_ctx->pagev[num_pages]) {
1658 				__free_page(block_ctx->pagev[num_pages]);
1659 				block_ctx->pagev[num_pages] = NULL;
1660 			}
1661 		}
1662 
1663 		kfree(block_ctx->mem_to_free);
1664 		block_ctx->mem_to_free = NULL;
1665 		block_ctx->pagev = NULL;
1666 		block_ctx->datav = NULL;
1667 	}
1668 }
1669 
1670 static int btrfsic_read_block(struct btrfsic_state *state,
1671 			      struct btrfsic_block_data_ctx *block_ctx)
1672 {
1673 	unsigned int num_pages;
1674 	unsigned int i;
1675 	u64 dev_bytenr;
1676 	int ret;
1677 
1678 	BUG_ON(block_ctx->datav);
1679 	BUG_ON(block_ctx->pagev);
1680 	BUG_ON(block_ctx->mem_to_free);
1681 	if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1682 		printk(KERN_INFO
1683 		       "btrfsic: read_block() with unaligned bytenr %llu\n",
1684 		       (unsigned long long)block_ctx->dev_bytenr);
1685 		return -1;
1686 	}
1687 
1688 	num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1689 		    PAGE_CACHE_SHIFT;
1690 	block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1691 					  sizeof(*block_ctx->pagev)) *
1692 					 num_pages, GFP_NOFS);
1693 	if (!block_ctx->mem_to_free)
1694 		return -1;
1695 	block_ctx->datav = block_ctx->mem_to_free;
1696 	block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1697 	for (i = 0; i < num_pages; i++) {
1698 		block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1699 		if (!block_ctx->pagev[i])
1700 			return -1;
1701 	}
1702 
1703 	dev_bytenr = block_ctx->dev_bytenr;
1704 	for (i = 0; i < num_pages;) {
1705 		struct bio *bio;
1706 		unsigned int j;
1707 		DECLARE_COMPLETION_ONSTACK(complete);
1708 
1709 		bio = btrfs_io_bio_alloc(GFP_NOFS, num_pages - i);
1710 		if (!bio) {
1711 			printk(KERN_INFO
1712 			       "btrfsic: bio_alloc() for %u pages failed!\n",
1713 			       num_pages - i);
1714 			return -1;
1715 		}
1716 		bio->bi_bdev = block_ctx->dev->bdev;
1717 		bio->bi_sector = dev_bytenr >> 9;
1718 		bio->bi_end_io = btrfsic_complete_bio_end_io;
1719 		bio->bi_private = &complete;
1720 
1721 		for (j = i; j < num_pages; j++) {
1722 			ret = bio_add_page(bio, block_ctx->pagev[j],
1723 					   PAGE_CACHE_SIZE, 0);
1724 			if (PAGE_CACHE_SIZE != ret)
1725 				break;
1726 		}
1727 		if (j == i) {
1728 			printk(KERN_INFO
1729 			       "btrfsic: error, failed to add a single page!\n");
1730 			return -1;
1731 		}
1732 		submit_bio(READ, bio);
1733 
1734 		/* this will also unplug the queue */
1735 		wait_for_completion(&complete);
1736 
1737 		if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
1738 			printk(KERN_INFO
1739 			       "btrfsic: read error at logical %llu dev %s!\n",
1740 			       block_ctx->start, block_ctx->dev->name);
1741 			bio_put(bio);
1742 			return -1;
1743 		}
1744 		bio_put(bio);
1745 		dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1746 		i = j;
1747 	}
1748 	for (i = 0; i < num_pages; i++) {
1749 		block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1750 		if (!block_ctx->datav[i]) {
1751 			printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1752 			       block_ctx->dev->name);
1753 			return -1;
1754 		}
1755 	}
1756 
1757 	return block_ctx->len;
1758 }
1759 
1760 static void btrfsic_complete_bio_end_io(struct bio *bio, int err)
1761 {
1762 	complete((struct completion *)bio->bi_private);
1763 }
1764 
1765 static void btrfsic_dump_database(struct btrfsic_state *state)
1766 {
1767 	struct list_head *elem_all;
1768 
1769 	BUG_ON(NULL == state);
1770 
1771 	printk(KERN_INFO "all_blocks_list:\n");
1772 	list_for_each(elem_all, &state->all_blocks_list) {
1773 		const struct btrfsic_block *const b_all =
1774 		    list_entry(elem_all, struct btrfsic_block,
1775 			       all_blocks_node);
1776 		struct list_head *elem_ref_to;
1777 		struct list_head *elem_ref_from;
1778 
1779 		printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1780 		       btrfsic_get_block_type(state, b_all),
1781 		       (unsigned long long)b_all->logical_bytenr,
1782 		       b_all->dev_state->name,
1783 		       (unsigned long long)b_all->dev_bytenr,
1784 		       b_all->mirror_num);
1785 
1786 		list_for_each(elem_ref_to, &b_all->ref_to_list) {
1787 			const struct btrfsic_block_link *const l =
1788 			    list_entry(elem_ref_to,
1789 				       struct btrfsic_block_link,
1790 				       node_ref_to);
1791 
1792 			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1793 			       " refers %u* to"
1794 			       " %c @%llu (%s/%llu/%d)\n",
1795 			       btrfsic_get_block_type(state, b_all),
1796 			       (unsigned long long)b_all->logical_bytenr,
1797 			       b_all->dev_state->name,
1798 			       (unsigned long long)b_all->dev_bytenr,
1799 			       b_all->mirror_num,
1800 			       l->ref_cnt,
1801 			       btrfsic_get_block_type(state, l->block_ref_to),
1802 			       (unsigned long long)
1803 			       l->block_ref_to->logical_bytenr,
1804 			       l->block_ref_to->dev_state->name,
1805 			       (unsigned long long)l->block_ref_to->dev_bytenr,
1806 			       l->block_ref_to->mirror_num);
1807 		}
1808 
1809 		list_for_each(elem_ref_from, &b_all->ref_from_list) {
1810 			const struct btrfsic_block_link *const l =
1811 			    list_entry(elem_ref_from,
1812 				       struct btrfsic_block_link,
1813 				       node_ref_from);
1814 
1815 			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1816 			       " is ref %u* from"
1817 			       " %c @%llu (%s/%llu/%d)\n",
1818 			       btrfsic_get_block_type(state, b_all),
1819 			       (unsigned long long)b_all->logical_bytenr,
1820 			       b_all->dev_state->name,
1821 			       (unsigned long long)b_all->dev_bytenr,
1822 			       b_all->mirror_num,
1823 			       l->ref_cnt,
1824 			       btrfsic_get_block_type(state, l->block_ref_from),
1825 			       (unsigned long long)
1826 			       l->block_ref_from->logical_bytenr,
1827 			       l->block_ref_from->dev_state->name,
1828 			       (unsigned long long)
1829 			       l->block_ref_from->dev_bytenr,
1830 			       l->block_ref_from->mirror_num);
1831 		}
1832 
1833 		printk(KERN_INFO "\n");
1834 	}
1835 }
1836 
1837 /*
1838  * Test whether the disk block contains a tree block (leaf or node)
1839  * (note that this test fails for the super block)
1840  */
1841 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1842 				     char **datav, unsigned int num_pages)
1843 {
1844 	struct btrfs_header *h;
1845 	u8 csum[BTRFS_CSUM_SIZE];
1846 	u32 crc = ~(u32)0;
1847 	unsigned int i;
1848 
1849 	if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1850 		return 1; /* not metadata */
1851 	num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1852 	h = (struct btrfs_header *)datav[0];
1853 
1854 	if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1855 		return 1;
1856 
1857 	for (i = 0; i < num_pages; i++) {
1858 		u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1859 		size_t sublen = i ? PAGE_CACHE_SIZE :
1860 				    (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1861 
1862 		crc = crc32c(crc, data, sublen);
1863 	}
1864 	btrfs_csum_final(crc, csum);
1865 	if (memcmp(csum, h->csum, state->csum_size))
1866 		return 1;
1867 
1868 	return 0; /* is metadata */
1869 }
1870 
1871 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1872 					  u64 dev_bytenr, char **mapped_datav,
1873 					  unsigned int num_pages,
1874 					  struct bio *bio, int *bio_is_patched,
1875 					  struct buffer_head *bh,
1876 					  int submit_bio_bh_rw)
1877 {
1878 	int is_metadata;
1879 	struct btrfsic_block *block;
1880 	struct btrfsic_block_data_ctx block_ctx;
1881 	int ret;
1882 	struct btrfsic_state *state = dev_state->state;
1883 	struct block_device *bdev = dev_state->bdev;
1884 	unsigned int processed_len;
1885 
1886 	if (NULL != bio_is_patched)
1887 		*bio_is_patched = 0;
1888 
1889 again:
1890 	if (num_pages == 0)
1891 		return;
1892 
1893 	processed_len = 0;
1894 	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1895 						      num_pages));
1896 
1897 	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1898 					       &state->block_hashtable);
1899 	if (NULL != block) {
1900 		u64 bytenr = 0;
1901 		struct list_head *elem_ref_to;
1902 		struct list_head *tmp_ref_to;
1903 
1904 		if (block->is_superblock) {
1905 			bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1906 						    mapped_datav[0]);
1907 			if (num_pages * PAGE_CACHE_SIZE <
1908 			    BTRFS_SUPER_INFO_SIZE) {
1909 				printk(KERN_INFO
1910 				       "btrfsic: cannot work with too short bios!\n");
1911 				return;
1912 			}
1913 			is_metadata = 1;
1914 			BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1915 			processed_len = BTRFS_SUPER_INFO_SIZE;
1916 			if (state->print_mask &
1917 			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1918 				printk(KERN_INFO
1919 				       "[before new superblock is written]:\n");
1920 				btrfsic_dump_tree_sub(state, block, 0);
1921 			}
1922 		}
1923 		if (is_metadata) {
1924 			if (!block->is_superblock) {
1925 				if (num_pages * PAGE_CACHE_SIZE <
1926 				    state->metablock_size) {
1927 					printk(KERN_INFO
1928 					       "btrfsic: cannot work with too short bios!\n");
1929 					return;
1930 				}
1931 				processed_len = state->metablock_size;
1932 				bytenr = btrfs_stack_header_bytenr(
1933 						(struct btrfs_header *)
1934 						mapped_datav[0]);
1935 				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1936 							       dev_state,
1937 							       dev_bytenr);
1938 			}
1939 			if (block->logical_bytenr != bytenr) {
1940 				printk(KERN_INFO
1941 				       "Written block @%llu (%s/%llu/%d)"
1942 				       " found in hash table, %c,"
1943 				       " bytenr mismatch"
1944 				       " (!= stored %llu).\n",
1945 				       (unsigned long long)bytenr,
1946 				       dev_state->name,
1947 				       (unsigned long long)dev_bytenr,
1948 				       block->mirror_num,
1949 				       btrfsic_get_block_type(state, block),
1950 				       (unsigned long long)
1951 				       block->logical_bytenr);
1952 				block->logical_bytenr = bytenr;
1953 			} else if (state->print_mask &
1954 				   BTRFSIC_PRINT_MASK_VERBOSE)
1955 				printk(KERN_INFO
1956 				       "Written block @%llu (%s/%llu/%d)"
1957 				       " found in hash table, %c.\n",
1958 				       (unsigned long long)bytenr,
1959 				       dev_state->name,
1960 				       (unsigned long long)dev_bytenr,
1961 				       block->mirror_num,
1962 				       btrfsic_get_block_type(state, block));
1963 		} else {
1964 			if (num_pages * PAGE_CACHE_SIZE <
1965 			    state->datablock_size) {
1966 				printk(KERN_INFO
1967 				       "btrfsic: cannot work with too short bios!\n");
1968 				return;
1969 			}
1970 			processed_len = state->datablock_size;
1971 			bytenr = block->logical_bytenr;
1972 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1973 				printk(KERN_INFO
1974 				       "Written block @%llu (%s/%llu/%d)"
1975 				       " found in hash table, %c.\n",
1976 				       (unsigned long long)bytenr,
1977 				       dev_state->name,
1978 				       (unsigned long long)dev_bytenr,
1979 				       block->mirror_num,
1980 				       btrfsic_get_block_type(state, block));
1981 		}
1982 
1983 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1984 			printk(KERN_INFO
1985 			       "ref_to_list: %cE, ref_from_list: %cE\n",
1986 			       list_empty(&block->ref_to_list) ? ' ' : '!',
1987 			       list_empty(&block->ref_from_list) ? ' ' : '!');
1988 		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1989 			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1990 			       " @%llu (%s/%llu/%d), old(gen=%llu,"
1991 			       " objectid=%llu, type=%d, offset=%llu),"
1992 			       " new(gen=%llu),"
1993 			       " which is referenced by most recent superblock"
1994 			       " (superblockgen=%llu)!\n",
1995 			       btrfsic_get_block_type(state, block),
1996 			       (unsigned long long)bytenr,
1997 			       dev_state->name,
1998 			       (unsigned long long)dev_bytenr,
1999 			       block->mirror_num,
2000 			       (unsigned long long)block->generation,
2001 			       (unsigned long long)
2002 			       btrfs_disk_key_objectid(&block->disk_key),
2003 			       block->disk_key.type,
2004 			       (unsigned long long)
2005 			       btrfs_disk_key_offset(&block->disk_key),
2006 			       (unsigned long long)
2007 			       btrfs_stack_header_generation(
2008 				       (struct btrfs_header *) mapped_datav[0]),
2009 			       (unsigned long long)
2010 			       state->max_superblock_generation);
2011 			btrfsic_dump_tree(state);
2012 		}
2013 
2014 		if (!block->is_iodone && !block->never_written) {
2015 			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
2016 			       " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
2017 			       " which is not yet iodone!\n",
2018 			       btrfsic_get_block_type(state, block),
2019 			       (unsigned long long)bytenr,
2020 			       dev_state->name,
2021 			       (unsigned long long)dev_bytenr,
2022 			       block->mirror_num,
2023 			       (unsigned long long)block->generation,
2024 			       (unsigned long long)
2025 			       btrfs_stack_header_generation(
2026 				       (struct btrfs_header *)
2027 				       mapped_datav[0]));
2028 			/* it would not be safe to go on */
2029 			btrfsic_dump_tree(state);
2030 			goto continue_loop;
2031 		}
2032 
2033 		/*
2034 		 * Clear all references of this block. Do not free
2035 		 * the block itself even if is not referenced anymore
2036 		 * because it still carries valueable information
2037 		 * like whether it was ever written and IO completed.
2038 		 */
2039 		list_for_each_safe(elem_ref_to, tmp_ref_to,
2040 				   &block->ref_to_list) {
2041 			struct btrfsic_block_link *const l =
2042 			    list_entry(elem_ref_to,
2043 				       struct btrfsic_block_link,
2044 				       node_ref_to);
2045 
2046 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2047 				btrfsic_print_rem_link(state, l);
2048 			l->ref_cnt--;
2049 			if (0 == l->ref_cnt) {
2050 				list_del(&l->node_ref_to);
2051 				list_del(&l->node_ref_from);
2052 				btrfsic_block_link_hashtable_remove(l);
2053 				btrfsic_block_link_free(l);
2054 			}
2055 		}
2056 
2057 		if (block->is_superblock)
2058 			ret = btrfsic_map_superblock(state, bytenr,
2059 						     processed_len,
2060 						     bdev, &block_ctx);
2061 		else
2062 			ret = btrfsic_map_block(state, bytenr, processed_len,
2063 						&block_ctx, 0);
2064 		if (ret) {
2065 			printk(KERN_INFO
2066 			       "btrfsic: btrfsic_map_block(root @%llu)"
2067 			       " failed!\n", (unsigned long long)bytenr);
2068 			goto continue_loop;
2069 		}
2070 		block_ctx.datav = mapped_datav;
2071 		/* the following is required in case of writes to mirrors,
2072 		 * use the same that was used for the lookup */
2073 		block_ctx.dev = dev_state;
2074 		block_ctx.dev_bytenr = dev_bytenr;
2075 
2076 		if (is_metadata || state->include_extent_data) {
2077 			block->never_written = 0;
2078 			block->iodone_w_error = 0;
2079 			if (NULL != bio) {
2080 				block->is_iodone = 0;
2081 				BUG_ON(NULL == bio_is_patched);
2082 				if (!*bio_is_patched) {
2083 					block->orig_bio_bh_private =
2084 					    bio->bi_private;
2085 					block->orig_bio_bh_end_io.bio =
2086 					    bio->bi_end_io;
2087 					block->next_in_same_bio = NULL;
2088 					bio->bi_private = block;
2089 					bio->bi_end_io = btrfsic_bio_end_io;
2090 					*bio_is_patched = 1;
2091 				} else {
2092 					struct btrfsic_block *chained_block =
2093 					    (struct btrfsic_block *)
2094 					    bio->bi_private;
2095 
2096 					BUG_ON(NULL == chained_block);
2097 					block->orig_bio_bh_private =
2098 					    chained_block->orig_bio_bh_private;
2099 					block->orig_bio_bh_end_io.bio =
2100 					    chained_block->orig_bio_bh_end_io.
2101 					    bio;
2102 					block->next_in_same_bio = chained_block;
2103 					bio->bi_private = block;
2104 				}
2105 			} else if (NULL != bh) {
2106 				block->is_iodone = 0;
2107 				block->orig_bio_bh_private = bh->b_private;
2108 				block->orig_bio_bh_end_io.bh = bh->b_end_io;
2109 				block->next_in_same_bio = NULL;
2110 				bh->b_private = block;
2111 				bh->b_end_io = btrfsic_bh_end_io;
2112 			} else {
2113 				block->is_iodone = 1;
2114 				block->orig_bio_bh_private = NULL;
2115 				block->orig_bio_bh_end_io.bio = NULL;
2116 				block->next_in_same_bio = NULL;
2117 			}
2118 		}
2119 
2120 		block->flush_gen = dev_state->last_flush_gen + 1;
2121 		block->submit_bio_bh_rw = submit_bio_bh_rw;
2122 		if (is_metadata) {
2123 			block->logical_bytenr = bytenr;
2124 			block->is_metadata = 1;
2125 			if (block->is_superblock) {
2126 				BUG_ON(PAGE_CACHE_SIZE !=
2127 				       BTRFS_SUPER_INFO_SIZE);
2128 				ret = btrfsic_process_written_superblock(
2129 						state,
2130 						block,
2131 						(struct btrfs_super_block *)
2132 						mapped_datav[0]);
2133 				if (state->print_mask &
2134 				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2135 					printk(KERN_INFO
2136 					"[after new superblock is written]:\n");
2137 					btrfsic_dump_tree_sub(state, block, 0);
2138 				}
2139 			} else {
2140 				block->mirror_num = 0;	/* unknown */
2141 				ret = btrfsic_process_metablock(
2142 						state,
2143 						block,
2144 						&block_ctx,
2145 						0, 0);
2146 			}
2147 			if (ret)
2148 				printk(KERN_INFO
2149 				       "btrfsic: btrfsic_process_metablock"
2150 				       "(root @%llu) failed!\n",
2151 				       (unsigned long long)dev_bytenr);
2152 		} else {
2153 			block->is_metadata = 0;
2154 			block->mirror_num = 0;	/* unknown */
2155 			block->generation = BTRFSIC_GENERATION_UNKNOWN;
2156 			if (!state->include_extent_data
2157 			    && list_empty(&block->ref_from_list)) {
2158 				/*
2159 				 * disk block is overwritten with extent
2160 				 * data (not meta data) and we are configured
2161 				 * to not include extent data: take the
2162 				 * chance and free the block's memory
2163 				 */
2164 				btrfsic_block_hashtable_remove(block);
2165 				list_del(&block->all_blocks_node);
2166 				btrfsic_block_free(block);
2167 			}
2168 		}
2169 		btrfsic_release_block_ctx(&block_ctx);
2170 	} else {
2171 		/* block has not been found in hash table */
2172 		u64 bytenr;
2173 
2174 		if (!is_metadata) {
2175 			processed_len = state->datablock_size;
2176 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2177 				printk(KERN_INFO "Written block (%s/%llu/?)"
2178 				       " !found in hash table, D.\n",
2179 				       dev_state->name,
2180 				       (unsigned long long)dev_bytenr);
2181 			if (!state->include_extent_data) {
2182 				/* ignore that written D block */
2183 				goto continue_loop;
2184 			}
2185 
2186 			/* this is getting ugly for the
2187 			 * include_extent_data case... */
2188 			bytenr = 0;	/* unknown */
2189 			block_ctx.start = bytenr;
2190 			block_ctx.len = processed_len;
2191 			block_ctx.mem_to_free = NULL;
2192 			block_ctx.pagev = NULL;
2193 		} else {
2194 			processed_len = state->metablock_size;
2195 			bytenr = btrfs_stack_header_bytenr(
2196 					(struct btrfs_header *)
2197 					mapped_datav[0]);
2198 			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2199 						       dev_bytenr);
2200 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2201 				printk(KERN_INFO
2202 				       "Written block @%llu (%s/%llu/?)"
2203 				       " !found in hash table, M.\n",
2204 				       (unsigned long long)bytenr,
2205 				       dev_state->name,
2206 				       (unsigned long long)dev_bytenr);
2207 
2208 			ret = btrfsic_map_block(state, bytenr, processed_len,
2209 						&block_ctx, 0);
2210 			if (ret) {
2211 				printk(KERN_INFO
2212 				       "btrfsic: btrfsic_map_block(root @%llu)"
2213 				       " failed!\n",
2214 				       (unsigned long long)dev_bytenr);
2215 				goto continue_loop;
2216 			}
2217 		}
2218 		block_ctx.datav = mapped_datav;
2219 		/* the following is required in case of writes to mirrors,
2220 		 * use the same that was used for the lookup */
2221 		block_ctx.dev = dev_state;
2222 		block_ctx.dev_bytenr = dev_bytenr;
2223 
2224 		block = btrfsic_block_alloc();
2225 		if (NULL == block) {
2226 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2227 			btrfsic_release_block_ctx(&block_ctx);
2228 			goto continue_loop;
2229 		}
2230 		block->dev_state = dev_state;
2231 		block->dev_bytenr = dev_bytenr;
2232 		block->logical_bytenr = bytenr;
2233 		block->is_metadata = is_metadata;
2234 		block->never_written = 0;
2235 		block->iodone_w_error = 0;
2236 		block->mirror_num = 0;	/* unknown */
2237 		block->flush_gen = dev_state->last_flush_gen + 1;
2238 		block->submit_bio_bh_rw = submit_bio_bh_rw;
2239 		if (NULL != bio) {
2240 			block->is_iodone = 0;
2241 			BUG_ON(NULL == bio_is_patched);
2242 			if (!*bio_is_patched) {
2243 				block->orig_bio_bh_private = bio->bi_private;
2244 				block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2245 				block->next_in_same_bio = NULL;
2246 				bio->bi_private = block;
2247 				bio->bi_end_io = btrfsic_bio_end_io;
2248 				*bio_is_patched = 1;
2249 			} else {
2250 				struct btrfsic_block *chained_block =
2251 				    (struct btrfsic_block *)
2252 				    bio->bi_private;
2253 
2254 				BUG_ON(NULL == chained_block);
2255 				block->orig_bio_bh_private =
2256 				    chained_block->orig_bio_bh_private;
2257 				block->orig_bio_bh_end_io.bio =
2258 				    chained_block->orig_bio_bh_end_io.bio;
2259 				block->next_in_same_bio = chained_block;
2260 				bio->bi_private = block;
2261 			}
2262 		} else if (NULL != bh) {
2263 			block->is_iodone = 0;
2264 			block->orig_bio_bh_private = bh->b_private;
2265 			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2266 			block->next_in_same_bio = NULL;
2267 			bh->b_private = block;
2268 			bh->b_end_io = btrfsic_bh_end_io;
2269 		} else {
2270 			block->is_iodone = 1;
2271 			block->orig_bio_bh_private = NULL;
2272 			block->orig_bio_bh_end_io.bio = NULL;
2273 			block->next_in_same_bio = NULL;
2274 		}
2275 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2276 			printk(KERN_INFO
2277 			       "New written %c-block @%llu (%s/%llu/%d)\n",
2278 			       is_metadata ? 'M' : 'D',
2279 			       (unsigned long long)block->logical_bytenr,
2280 			       block->dev_state->name,
2281 			       (unsigned long long)block->dev_bytenr,
2282 			       block->mirror_num);
2283 		list_add(&block->all_blocks_node, &state->all_blocks_list);
2284 		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2285 
2286 		if (is_metadata) {
2287 			ret = btrfsic_process_metablock(state, block,
2288 							&block_ctx, 0, 0);
2289 			if (ret)
2290 				printk(KERN_INFO
2291 				       "btrfsic: process_metablock(root @%llu)"
2292 				       " failed!\n",
2293 				       (unsigned long long)dev_bytenr);
2294 		}
2295 		btrfsic_release_block_ctx(&block_ctx);
2296 	}
2297 
2298 continue_loop:
2299 	BUG_ON(!processed_len);
2300 	dev_bytenr += processed_len;
2301 	mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2302 	num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2303 	goto again;
2304 }
2305 
2306 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2307 {
2308 	struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2309 	int iodone_w_error;
2310 
2311 	/* mutex is not held! This is not save if IO is not yet completed
2312 	 * on umount */
2313 	iodone_w_error = 0;
2314 	if (bio_error_status)
2315 		iodone_w_error = 1;
2316 
2317 	BUG_ON(NULL == block);
2318 	bp->bi_private = block->orig_bio_bh_private;
2319 	bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2320 
2321 	do {
2322 		struct btrfsic_block *next_block;
2323 		struct btrfsic_dev_state *const dev_state = block->dev_state;
2324 
2325 		if ((dev_state->state->print_mask &
2326 		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2327 			printk(KERN_INFO
2328 			       "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2329 			       bio_error_status,
2330 			       btrfsic_get_block_type(dev_state->state, block),
2331 			       (unsigned long long)block->logical_bytenr,
2332 			       dev_state->name,
2333 			       (unsigned long long)block->dev_bytenr,
2334 			       block->mirror_num);
2335 		next_block = block->next_in_same_bio;
2336 		block->iodone_w_error = iodone_w_error;
2337 		if (block->submit_bio_bh_rw & REQ_FLUSH) {
2338 			dev_state->last_flush_gen++;
2339 			if ((dev_state->state->print_mask &
2340 			     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2341 				printk(KERN_INFO
2342 				       "bio_end_io() new %s flush_gen=%llu\n",
2343 				       dev_state->name,
2344 				       (unsigned long long)
2345 				       dev_state->last_flush_gen);
2346 		}
2347 		if (block->submit_bio_bh_rw & REQ_FUA)
2348 			block->flush_gen = 0; /* FUA completed means block is
2349 					       * on disk */
2350 		block->is_iodone = 1; /* for FLUSH, this releases the block */
2351 		block = next_block;
2352 	} while (NULL != block);
2353 
2354 	bp->bi_end_io(bp, bio_error_status);
2355 }
2356 
2357 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2358 {
2359 	struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2360 	int iodone_w_error = !uptodate;
2361 	struct btrfsic_dev_state *dev_state;
2362 
2363 	BUG_ON(NULL == block);
2364 	dev_state = block->dev_state;
2365 	if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2366 		printk(KERN_INFO
2367 		       "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2368 		       iodone_w_error,
2369 		       btrfsic_get_block_type(dev_state->state, block),
2370 		       (unsigned long long)block->logical_bytenr,
2371 		       block->dev_state->name,
2372 		       (unsigned long long)block->dev_bytenr,
2373 		       block->mirror_num);
2374 
2375 	block->iodone_w_error = iodone_w_error;
2376 	if (block->submit_bio_bh_rw & REQ_FLUSH) {
2377 		dev_state->last_flush_gen++;
2378 		if ((dev_state->state->print_mask &
2379 		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2380 			printk(KERN_INFO
2381 			       "bh_end_io() new %s flush_gen=%llu\n",
2382 			       dev_state->name,
2383 			       (unsigned long long)dev_state->last_flush_gen);
2384 	}
2385 	if (block->submit_bio_bh_rw & REQ_FUA)
2386 		block->flush_gen = 0; /* FUA completed means block is on disk */
2387 
2388 	bh->b_private = block->orig_bio_bh_private;
2389 	bh->b_end_io = block->orig_bio_bh_end_io.bh;
2390 	block->is_iodone = 1; /* for FLUSH, this releases the block */
2391 	bh->b_end_io(bh, uptodate);
2392 }
2393 
2394 static int btrfsic_process_written_superblock(
2395 		struct btrfsic_state *state,
2396 		struct btrfsic_block *const superblock,
2397 		struct btrfs_super_block *const super_hdr)
2398 {
2399 	int pass;
2400 
2401 	superblock->generation = btrfs_super_generation(super_hdr);
2402 	if (!(superblock->generation > state->max_superblock_generation ||
2403 	      0 == state->max_superblock_generation)) {
2404 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2405 			printk(KERN_INFO
2406 			       "btrfsic: superblock @%llu (%s/%llu/%d)"
2407 			       " with old gen %llu <= %llu\n",
2408 			       (unsigned long long)superblock->logical_bytenr,
2409 			       superblock->dev_state->name,
2410 			       (unsigned long long)superblock->dev_bytenr,
2411 			       superblock->mirror_num,
2412 			       (unsigned long long)
2413 			       btrfs_super_generation(super_hdr),
2414 			       (unsigned long long)
2415 			       state->max_superblock_generation);
2416 	} else {
2417 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2418 			printk(KERN_INFO
2419 			       "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2420 			       " with new gen %llu > %llu\n",
2421 			       (unsigned long long)superblock->logical_bytenr,
2422 			       superblock->dev_state->name,
2423 			       (unsigned long long)superblock->dev_bytenr,
2424 			       superblock->mirror_num,
2425 			       (unsigned long long)
2426 			       btrfs_super_generation(super_hdr),
2427 			       (unsigned long long)
2428 			       state->max_superblock_generation);
2429 
2430 		state->max_superblock_generation =
2431 		    btrfs_super_generation(super_hdr);
2432 		state->latest_superblock = superblock;
2433 	}
2434 
2435 	for (pass = 0; pass < 3; pass++) {
2436 		int ret;
2437 		u64 next_bytenr;
2438 		struct btrfsic_block *next_block;
2439 		struct btrfsic_block_data_ctx tmp_next_block_ctx;
2440 		struct btrfsic_block_link *l;
2441 		int num_copies;
2442 		int mirror_num;
2443 		const char *additional_string = NULL;
2444 		struct btrfs_disk_key tmp_disk_key = {0};
2445 
2446 		btrfs_set_disk_key_objectid(&tmp_disk_key,
2447 					    BTRFS_ROOT_ITEM_KEY);
2448 		btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2449 
2450 		switch (pass) {
2451 		case 0:
2452 			btrfs_set_disk_key_objectid(&tmp_disk_key,
2453 						    BTRFS_ROOT_TREE_OBJECTID);
2454 			additional_string = "root ";
2455 			next_bytenr = btrfs_super_root(super_hdr);
2456 			if (state->print_mask &
2457 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2458 				printk(KERN_INFO "root@%llu\n",
2459 				       (unsigned long long)next_bytenr);
2460 			break;
2461 		case 1:
2462 			btrfs_set_disk_key_objectid(&tmp_disk_key,
2463 						    BTRFS_CHUNK_TREE_OBJECTID);
2464 			additional_string = "chunk ";
2465 			next_bytenr = btrfs_super_chunk_root(super_hdr);
2466 			if (state->print_mask &
2467 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2468 				printk(KERN_INFO "chunk@%llu\n",
2469 				       (unsigned long long)next_bytenr);
2470 			break;
2471 		case 2:
2472 			btrfs_set_disk_key_objectid(&tmp_disk_key,
2473 						    BTRFS_TREE_LOG_OBJECTID);
2474 			additional_string = "log ";
2475 			next_bytenr = btrfs_super_log_root(super_hdr);
2476 			if (0 == next_bytenr)
2477 				continue;
2478 			if (state->print_mask &
2479 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2480 				printk(KERN_INFO "log@%llu\n",
2481 				       (unsigned long long)next_bytenr);
2482 			break;
2483 		}
2484 
2485 		num_copies =
2486 		    btrfs_num_copies(state->root->fs_info,
2487 				     next_bytenr, BTRFS_SUPER_INFO_SIZE);
2488 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2489 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2490 			       (unsigned long long)next_bytenr, num_copies);
2491 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2492 			int was_created;
2493 
2494 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2495 				printk(KERN_INFO
2496 				       "btrfsic_process_written_superblock("
2497 				       "mirror_num=%d)\n", mirror_num);
2498 			ret = btrfsic_map_block(state, next_bytenr,
2499 						BTRFS_SUPER_INFO_SIZE,
2500 						&tmp_next_block_ctx,
2501 						mirror_num);
2502 			if (ret) {
2503 				printk(KERN_INFO
2504 				       "btrfsic: btrfsic_map_block(@%llu,"
2505 				       " mirror=%d) failed!\n",
2506 				       (unsigned long long)next_bytenr,
2507 				       mirror_num);
2508 				return -1;
2509 			}
2510 
2511 			next_block = btrfsic_block_lookup_or_add(
2512 					state,
2513 					&tmp_next_block_ctx,
2514 					additional_string,
2515 					1, 0, 1,
2516 					mirror_num,
2517 					&was_created);
2518 			if (NULL == next_block) {
2519 				printk(KERN_INFO
2520 				       "btrfsic: error, kmalloc failed!\n");
2521 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
2522 				return -1;
2523 			}
2524 
2525 			next_block->disk_key = tmp_disk_key;
2526 			if (was_created)
2527 				next_block->generation =
2528 				    BTRFSIC_GENERATION_UNKNOWN;
2529 			l = btrfsic_block_link_lookup_or_add(
2530 					state,
2531 					&tmp_next_block_ctx,
2532 					next_block,
2533 					superblock,
2534 					BTRFSIC_GENERATION_UNKNOWN);
2535 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
2536 			if (NULL == l)
2537 				return -1;
2538 		}
2539 	}
2540 
2541 	if (-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)) {
2542 		WARN_ON(1);
2543 		btrfsic_dump_tree(state);
2544 	}
2545 
2546 	return 0;
2547 }
2548 
2549 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2550 					struct btrfsic_block *const block,
2551 					int recursion_level)
2552 {
2553 	struct list_head *elem_ref_to;
2554 	int ret = 0;
2555 
2556 	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2557 		/*
2558 		 * Note that this situation can happen and does not
2559 		 * indicate an error in regular cases. It happens
2560 		 * when disk blocks are freed and later reused.
2561 		 * The check-integrity module is not aware of any
2562 		 * block free operations, it just recognizes block
2563 		 * write operations. Therefore it keeps the linkage
2564 		 * information for a block until a block is
2565 		 * rewritten. This can temporarily cause incorrect
2566 		 * and even circular linkage informations. This
2567 		 * causes no harm unless such blocks are referenced
2568 		 * by the most recent super block.
2569 		 */
2570 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2571 			printk(KERN_INFO
2572 			       "btrfsic: abort cyclic linkage (case 1).\n");
2573 
2574 		return ret;
2575 	}
2576 
2577 	/*
2578 	 * This algorithm is recursive because the amount of used stack
2579 	 * space is very small and the max recursion depth is limited.
2580 	 */
2581 	list_for_each(elem_ref_to, &block->ref_to_list) {
2582 		const struct btrfsic_block_link *const l =
2583 		    list_entry(elem_ref_to, struct btrfsic_block_link,
2584 			       node_ref_to);
2585 
2586 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2587 			printk(KERN_INFO
2588 			       "rl=%d, %c @%llu (%s/%llu/%d)"
2589 			       " %u* refers to %c @%llu (%s/%llu/%d)\n",
2590 			       recursion_level,
2591 			       btrfsic_get_block_type(state, block),
2592 			       (unsigned long long)block->logical_bytenr,
2593 			       block->dev_state->name,
2594 			       (unsigned long long)block->dev_bytenr,
2595 			       block->mirror_num,
2596 			       l->ref_cnt,
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 		if (l->block_ref_to->never_written) {
2604 			printk(KERN_INFO "btrfs: attempt to write superblock"
2605 			       " which references block %c @%llu (%s/%llu/%d)"
2606 			       " which is never written!\n",
2607 			       btrfsic_get_block_type(state, l->block_ref_to),
2608 			       (unsigned long long)
2609 			       l->block_ref_to->logical_bytenr,
2610 			       l->block_ref_to->dev_state->name,
2611 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2612 			       l->block_ref_to->mirror_num);
2613 			ret = -1;
2614 		} else if (!l->block_ref_to->is_iodone) {
2615 			printk(KERN_INFO "btrfs: attempt to write superblock"
2616 			       " which references block %c @%llu (%s/%llu/%d)"
2617 			       " which is not yet iodone!\n",
2618 			       btrfsic_get_block_type(state, l->block_ref_to),
2619 			       (unsigned long long)
2620 			       l->block_ref_to->logical_bytenr,
2621 			       l->block_ref_to->dev_state->name,
2622 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2623 			       l->block_ref_to->mirror_num);
2624 			ret = -1;
2625 		} else if (l->block_ref_to->iodone_w_error) {
2626 			printk(KERN_INFO "btrfs: attempt to write superblock"
2627 			       " which references block %c @%llu (%s/%llu/%d)"
2628 			       " which has write error!\n",
2629 			       btrfsic_get_block_type(state, l->block_ref_to),
2630 			       (unsigned long long)
2631 			       l->block_ref_to->logical_bytenr,
2632 			       l->block_ref_to->dev_state->name,
2633 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2634 			       l->block_ref_to->mirror_num);
2635 			ret = -1;
2636 		} else if (l->parent_generation !=
2637 			   l->block_ref_to->generation &&
2638 			   BTRFSIC_GENERATION_UNKNOWN !=
2639 			   l->parent_generation &&
2640 			   BTRFSIC_GENERATION_UNKNOWN !=
2641 			   l->block_ref_to->generation) {
2642 			printk(KERN_INFO "btrfs: attempt to write superblock"
2643 			       " which references block %c @%llu (%s/%llu/%d)"
2644 			       " with generation %llu !="
2645 			       " parent generation %llu!\n",
2646 			       btrfsic_get_block_type(state, l->block_ref_to),
2647 			       (unsigned long long)
2648 			       l->block_ref_to->logical_bytenr,
2649 			       l->block_ref_to->dev_state->name,
2650 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2651 			       l->block_ref_to->mirror_num,
2652 			       (unsigned long long)l->block_ref_to->generation,
2653 			       (unsigned long long)l->parent_generation);
2654 			ret = -1;
2655 		} else if (l->block_ref_to->flush_gen >
2656 			   l->block_ref_to->dev_state->last_flush_gen) {
2657 			printk(KERN_INFO "btrfs: attempt to write superblock"
2658 			       " which references block %c @%llu (%s/%llu/%d)"
2659 			       " which is not flushed out of disk's write cache"
2660 			       " (block flush_gen=%llu,"
2661 			       " dev->flush_gen=%llu)!\n",
2662 			       btrfsic_get_block_type(state, l->block_ref_to),
2663 			       (unsigned long long)
2664 			       l->block_ref_to->logical_bytenr,
2665 			       l->block_ref_to->dev_state->name,
2666 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2667 			       l->block_ref_to->mirror_num,
2668 			       (unsigned long long)block->flush_gen,
2669 			       (unsigned long long)
2670 			       l->block_ref_to->dev_state->last_flush_gen);
2671 			ret = -1;
2672 		} else if (-1 == btrfsic_check_all_ref_blocks(state,
2673 							      l->block_ref_to,
2674 							      recursion_level +
2675 							      1)) {
2676 			ret = -1;
2677 		}
2678 	}
2679 
2680 	return ret;
2681 }
2682 
2683 static int btrfsic_is_block_ref_by_superblock(
2684 		const struct btrfsic_state *state,
2685 		const struct btrfsic_block *block,
2686 		int recursion_level)
2687 {
2688 	struct list_head *elem_ref_from;
2689 
2690 	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2691 		/* refer to comment at "abort cyclic linkage (case 1)" */
2692 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2693 			printk(KERN_INFO
2694 			       "btrfsic: abort cyclic linkage (case 2).\n");
2695 
2696 		return 0;
2697 	}
2698 
2699 	/*
2700 	 * This algorithm is recursive because the amount of used stack space
2701 	 * is very small and the max recursion depth is limited.
2702 	 */
2703 	list_for_each(elem_ref_from, &block->ref_from_list) {
2704 		const struct btrfsic_block_link *const l =
2705 		    list_entry(elem_ref_from, struct btrfsic_block_link,
2706 			       node_ref_from);
2707 
2708 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2709 			printk(KERN_INFO
2710 			       "rl=%d, %c @%llu (%s/%llu/%d)"
2711 			       " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2712 			       recursion_level,
2713 			       btrfsic_get_block_type(state, block),
2714 			       (unsigned long long)block->logical_bytenr,
2715 			       block->dev_state->name,
2716 			       (unsigned long long)block->dev_bytenr,
2717 			       block->mirror_num,
2718 			       l->ref_cnt,
2719 			       btrfsic_get_block_type(state, l->block_ref_from),
2720 			       (unsigned long long)
2721 			       l->block_ref_from->logical_bytenr,
2722 			       l->block_ref_from->dev_state->name,
2723 			       (unsigned long long)
2724 			       l->block_ref_from->dev_bytenr,
2725 			       l->block_ref_from->mirror_num);
2726 		if (l->block_ref_from->is_superblock &&
2727 		    state->latest_superblock->dev_bytenr ==
2728 		    l->block_ref_from->dev_bytenr &&
2729 		    state->latest_superblock->dev_state->bdev ==
2730 		    l->block_ref_from->dev_state->bdev)
2731 			return 1;
2732 		else if (btrfsic_is_block_ref_by_superblock(state,
2733 							    l->block_ref_from,
2734 							    recursion_level +
2735 							    1))
2736 			return 1;
2737 	}
2738 
2739 	return 0;
2740 }
2741 
2742 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2743 				   const struct btrfsic_block_link *l)
2744 {
2745 	printk(KERN_INFO
2746 	       "Add %u* link from %c @%llu (%s/%llu/%d)"
2747 	       " to %c @%llu (%s/%llu/%d).\n",
2748 	       l->ref_cnt,
2749 	       btrfsic_get_block_type(state, l->block_ref_from),
2750 	       (unsigned long long)l->block_ref_from->logical_bytenr,
2751 	       l->block_ref_from->dev_state->name,
2752 	       (unsigned long long)l->block_ref_from->dev_bytenr,
2753 	       l->block_ref_from->mirror_num,
2754 	       btrfsic_get_block_type(state, l->block_ref_to),
2755 	       (unsigned long long)l->block_ref_to->logical_bytenr,
2756 	       l->block_ref_to->dev_state->name,
2757 	       (unsigned long long)l->block_ref_to->dev_bytenr,
2758 	       l->block_ref_to->mirror_num);
2759 }
2760 
2761 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2762 				   const struct btrfsic_block_link *l)
2763 {
2764 	printk(KERN_INFO
2765 	       "Rem %u* link from %c @%llu (%s/%llu/%d)"
2766 	       " to %c @%llu (%s/%llu/%d).\n",
2767 	       l->ref_cnt,
2768 	       btrfsic_get_block_type(state, l->block_ref_from),
2769 	       (unsigned long long)l->block_ref_from->logical_bytenr,
2770 	       l->block_ref_from->dev_state->name,
2771 	       (unsigned long long)l->block_ref_from->dev_bytenr,
2772 	       l->block_ref_from->mirror_num,
2773 	       btrfsic_get_block_type(state, l->block_ref_to),
2774 	       (unsigned long long)l->block_ref_to->logical_bytenr,
2775 	       l->block_ref_to->dev_state->name,
2776 	       (unsigned long long)l->block_ref_to->dev_bytenr,
2777 	       l->block_ref_to->mirror_num);
2778 }
2779 
2780 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2781 				   const struct btrfsic_block *block)
2782 {
2783 	if (block->is_superblock &&
2784 	    state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2785 	    state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2786 		return 'S';
2787 	else if (block->is_superblock)
2788 		return 's';
2789 	else if (block->is_metadata)
2790 		return 'M';
2791 	else
2792 		return 'D';
2793 }
2794 
2795 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2796 {
2797 	btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2798 }
2799 
2800 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2801 				  const struct btrfsic_block *block,
2802 				  int indent_level)
2803 {
2804 	struct list_head *elem_ref_to;
2805 	int indent_add;
2806 	static char buf[80];
2807 	int cursor_position;
2808 
2809 	/*
2810 	 * Should better fill an on-stack buffer with a complete line and
2811 	 * dump it at once when it is time to print a newline character.
2812 	 */
2813 
2814 	/*
2815 	 * This algorithm is recursive because the amount of used stack space
2816 	 * is very small and the max recursion depth is limited.
2817 	 */
2818 	indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2819 			     btrfsic_get_block_type(state, block),
2820 			     (unsigned long long)block->logical_bytenr,
2821 			     block->dev_state->name,
2822 			     (unsigned long long)block->dev_bytenr,
2823 			     block->mirror_num);
2824 	if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2825 		printk("[...]\n");
2826 		return;
2827 	}
2828 	printk(buf);
2829 	indent_level += indent_add;
2830 	if (list_empty(&block->ref_to_list)) {
2831 		printk("\n");
2832 		return;
2833 	}
2834 	if (block->mirror_num > 1 &&
2835 	    !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2836 		printk(" [...]\n");
2837 		return;
2838 	}
2839 
2840 	cursor_position = indent_level;
2841 	list_for_each(elem_ref_to, &block->ref_to_list) {
2842 		const struct btrfsic_block_link *const l =
2843 		    list_entry(elem_ref_to, struct btrfsic_block_link,
2844 			       node_ref_to);
2845 
2846 		while (cursor_position < indent_level) {
2847 			printk(" ");
2848 			cursor_position++;
2849 		}
2850 		if (l->ref_cnt > 1)
2851 			indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2852 		else
2853 			indent_add = sprintf(buf, " --> ");
2854 		if (indent_level + indent_add >
2855 		    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2856 			printk("[...]\n");
2857 			cursor_position = 0;
2858 			continue;
2859 		}
2860 
2861 		printk(buf);
2862 
2863 		btrfsic_dump_tree_sub(state, l->block_ref_to,
2864 				      indent_level + indent_add);
2865 		cursor_position = 0;
2866 	}
2867 }
2868 
2869 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2870 		struct btrfsic_state *state,
2871 		struct btrfsic_block_data_ctx *next_block_ctx,
2872 		struct btrfsic_block *next_block,
2873 		struct btrfsic_block *from_block,
2874 		u64 parent_generation)
2875 {
2876 	struct btrfsic_block_link *l;
2877 
2878 	l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2879 						next_block_ctx->dev_bytenr,
2880 						from_block->dev_state->bdev,
2881 						from_block->dev_bytenr,
2882 						&state->block_link_hashtable);
2883 	if (NULL == l) {
2884 		l = btrfsic_block_link_alloc();
2885 		if (NULL == l) {
2886 			printk(KERN_INFO
2887 			       "btrfsic: error, kmalloc" " failed!\n");
2888 			return NULL;
2889 		}
2890 
2891 		l->block_ref_to = next_block;
2892 		l->block_ref_from = from_block;
2893 		l->ref_cnt = 1;
2894 		l->parent_generation = parent_generation;
2895 
2896 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2897 			btrfsic_print_add_link(state, l);
2898 
2899 		list_add(&l->node_ref_to, &from_block->ref_to_list);
2900 		list_add(&l->node_ref_from, &next_block->ref_from_list);
2901 
2902 		btrfsic_block_link_hashtable_add(l,
2903 						 &state->block_link_hashtable);
2904 	} else {
2905 		l->ref_cnt++;
2906 		l->parent_generation = parent_generation;
2907 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2908 			btrfsic_print_add_link(state, l);
2909 	}
2910 
2911 	return l;
2912 }
2913 
2914 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2915 		struct btrfsic_state *state,
2916 		struct btrfsic_block_data_ctx *block_ctx,
2917 		const char *additional_string,
2918 		int is_metadata,
2919 		int is_iodone,
2920 		int never_written,
2921 		int mirror_num,
2922 		int *was_created)
2923 {
2924 	struct btrfsic_block *block;
2925 
2926 	block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2927 					       block_ctx->dev_bytenr,
2928 					       &state->block_hashtable);
2929 	if (NULL == block) {
2930 		struct btrfsic_dev_state *dev_state;
2931 
2932 		block = btrfsic_block_alloc();
2933 		if (NULL == block) {
2934 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2935 			return NULL;
2936 		}
2937 		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2938 		if (NULL == dev_state) {
2939 			printk(KERN_INFO
2940 			       "btrfsic: error, lookup dev_state failed!\n");
2941 			btrfsic_block_free(block);
2942 			return NULL;
2943 		}
2944 		block->dev_state = dev_state;
2945 		block->dev_bytenr = block_ctx->dev_bytenr;
2946 		block->logical_bytenr = block_ctx->start;
2947 		block->is_metadata = is_metadata;
2948 		block->is_iodone = is_iodone;
2949 		block->never_written = never_written;
2950 		block->mirror_num = mirror_num;
2951 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2952 			printk(KERN_INFO
2953 			       "New %s%c-block @%llu (%s/%llu/%d)\n",
2954 			       additional_string,
2955 			       btrfsic_get_block_type(state, block),
2956 			       (unsigned long long)block->logical_bytenr,
2957 			       dev_state->name,
2958 			       (unsigned long long)block->dev_bytenr,
2959 			       mirror_num);
2960 		list_add(&block->all_blocks_node, &state->all_blocks_list);
2961 		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2962 		if (NULL != was_created)
2963 			*was_created = 1;
2964 	} else {
2965 		if (NULL != was_created)
2966 			*was_created = 0;
2967 	}
2968 
2969 	return block;
2970 }
2971 
2972 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2973 					   u64 bytenr,
2974 					   struct btrfsic_dev_state *dev_state,
2975 					   u64 dev_bytenr)
2976 {
2977 	int num_copies;
2978 	int mirror_num;
2979 	int ret;
2980 	struct btrfsic_block_data_ctx block_ctx;
2981 	int match = 0;
2982 
2983 	num_copies = btrfs_num_copies(state->root->fs_info,
2984 				      bytenr, state->metablock_size);
2985 
2986 	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2987 		ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2988 					&block_ctx, mirror_num);
2989 		if (ret) {
2990 			printk(KERN_INFO "btrfsic:"
2991 			       " btrfsic_map_block(logical @%llu,"
2992 			       " mirror %d) failed!\n",
2993 			       (unsigned long long)bytenr, mirror_num);
2994 			continue;
2995 		}
2996 
2997 		if (dev_state->bdev == block_ctx.dev->bdev &&
2998 		    dev_bytenr == block_ctx.dev_bytenr) {
2999 			match++;
3000 			btrfsic_release_block_ctx(&block_ctx);
3001 			break;
3002 		}
3003 		btrfsic_release_block_ctx(&block_ctx);
3004 	}
3005 
3006 	if (!match) {
3007 		printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
3008 		       " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
3009 		       " phys_bytenr=%llu)!\n",
3010 		       (unsigned long long)bytenr, dev_state->name,
3011 		       (unsigned long long)dev_bytenr);
3012 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
3013 			ret = btrfsic_map_block(state, bytenr,
3014 						state->metablock_size,
3015 						&block_ctx, mirror_num);
3016 			if (ret)
3017 				continue;
3018 
3019 			printk(KERN_INFO "Read logical bytenr @%llu maps to"
3020 			       " (%s/%llu/%d)\n",
3021 			       (unsigned long long)bytenr,
3022 			       block_ctx.dev->name,
3023 			       (unsigned long long)block_ctx.dev_bytenr,
3024 			       mirror_num);
3025 		}
3026 		WARN_ON(1);
3027 	}
3028 }
3029 
3030 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
3031 		struct block_device *bdev)
3032 {
3033 	struct btrfsic_dev_state *ds;
3034 
3035 	ds = btrfsic_dev_state_hashtable_lookup(bdev,
3036 						&btrfsic_dev_state_hashtable);
3037 	return ds;
3038 }
3039 
3040 int btrfsic_submit_bh(int rw, struct buffer_head *bh)
3041 {
3042 	struct btrfsic_dev_state *dev_state;
3043 
3044 	if (!btrfsic_is_initialized)
3045 		return submit_bh(rw, bh);
3046 
3047 	mutex_lock(&btrfsic_mutex);
3048 	/* since btrfsic_submit_bh() might also be called before
3049 	 * btrfsic_mount(), this might return NULL */
3050 	dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
3051 
3052 	/* Only called to write the superblock (incl. FLUSH/FUA) */
3053 	if (NULL != dev_state &&
3054 	    (rw & WRITE) && bh->b_size > 0) {
3055 		u64 dev_bytenr;
3056 
3057 		dev_bytenr = 4096 * bh->b_blocknr;
3058 		if (dev_state->state->print_mask &
3059 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3060 			printk(KERN_INFO
3061 			       "submit_bh(rw=0x%x, blocknr=%lu (bytenr %llu),"
3062 			       " size=%lu, data=%p, bdev=%p)\n",
3063 			       rw, (unsigned long)bh->b_blocknr,
3064 			       (unsigned long long)dev_bytenr,
3065 			       (unsigned long)bh->b_size, bh->b_data,
3066 			       bh->b_bdev);
3067 		btrfsic_process_written_block(dev_state, dev_bytenr,
3068 					      &bh->b_data, 1, NULL,
3069 					      NULL, bh, rw);
3070 	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3071 		if (dev_state->state->print_mask &
3072 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3073 			printk(KERN_INFO
3074 			       "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
3075 			       rw, bh->b_bdev);
3076 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3077 			if ((dev_state->state->print_mask &
3078 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3079 			      BTRFSIC_PRINT_MASK_VERBOSE)))
3080 				printk(KERN_INFO
3081 				       "btrfsic_submit_bh(%s) with FLUSH"
3082 				       " but dummy block already in use"
3083 				       " (ignored)!\n",
3084 				       dev_state->name);
3085 		} else {
3086 			struct btrfsic_block *const block =
3087 				&dev_state->dummy_block_for_bio_bh_flush;
3088 
3089 			block->is_iodone = 0;
3090 			block->never_written = 0;
3091 			block->iodone_w_error = 0;
3092 			block->flush_gen = dev_state->last_flush_gen + 1;
3093 			block->submit_bio_bh_rw = rw;
3094 			block->orig_bio_bh_private = bh->b_private;
3095 			block->orig_bio_bh_end_io.bh = bh->b_end_io;
3096 			block->next_in_same_bio = NULL;
3097 			bh->b_private = block;
3098 			bh->b_end_io = btrfsic_bh_end_io;
3099 		}
3100 	}
3101 	mutex_unlock(&btrfsic_mutex);
3102 	return submit_bh(rw, bh);
3103 }
3104 
3105 void btrfsic_submit_bio(int rw, struct bio *bio)
3106 {
3107 	struct btrfsic_dev_state *dev_state;
3108 
3109 	if (!btrfsic_is_initialized) {
3110 		submit_bio(rw, bio);
3111 		return;
3112 	}
3113 
3114 	mutex_lock(&btrfsic_mutex);
3115 	/* since btrfsic_submit_bio() is also called before
3116 	 * btrfsic_mount(), this might return NULL */
3117 	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
3118 	if (NULL != dev_state &&
3119 	    (rw & WRITE) && NULL != bio->bi_io_vec) {
3120 		unsigned int i;
3121 		u64 dev_bytenr;
3122 		int bio_is_patched;
3123 		char **mapped_datav;
3124 
3125 		dev_bytenr = 512 * bio->bi_sector;
3126 		bio_is_patched = 0;
3127 		if (dev_state->state->print_mask &
3128 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3129 			printk(KERN_INFO
3130 			       "submit_bio(rw=0x%x, bi_vcnt=%u,"
3131 			       " bi_sector=%lu (bytenr %llu), bi_bdev=%p)\n",
3132 			       rw, bio->bi_vcnt, (unsigned long)bio->bi_sector,
3133 			       (unsigned long long)dev_bytenr,
3134 			       bio->bi_bdev);
3135 
3136 		mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
3137 				       GFP_NOFS);
3138 		if (!mapped_datav)
3139 			goto leave;
3140 		for (i = 0; i < bio->bi_vcnt; i++) {
3141 			BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3142 			mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3143 			if (!mapped_datav[i]) {
3144 				while (i > 0) {
3145 					i--;
3146 					kunmap(bio->bi_io_vec[i].bv_page);
3147 				}
3148 				kfree(mapped_datav);
3149 				goto leave;
3150 			}
3151 			if ((BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3152 			     BTRFSIC_PRINT_MASK_VERBOSE) ==
3153 			    (dev_state->state->print_mask &
3154 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3155 			      BTRFSIC_PRINT_MASK_VERBOSE)))
3156 				printk(KERN_INFO
3157 				       "#%u: page=%p, len=%u, offset=%u\n",
3158 				       i, bio->bi_io_vec[i].bv_page,
3159 				       bio->bi_io_vec[i].bv_len,
3160 				       bio->bi_io_vec[i].bv_offset);
3161 		}
3162 		btrfsic_process_written_block(dev_state, dev_bytenr,
3163 					      mapped_datav, bio->bi_vcnt,
3164 					      bio, &bio_is_patched,
3165 					      NULL, rw);
3166 		while (i > 0) {
3167 			i--;
3168 			kunmap(bio->bi_io_vec[i].bv_page);
3169 		}
3170 		kfree(mapped_datav);
3171 	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3172 		if (dev_state->state->print_mask &
3173 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3174 			printk(KERN_INFO
3175 			       "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3176 			       rw, bio->bi_bdev);
3177 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3178 			if ((dev_state->state->print_mask &
3179 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3180 			      BTRFSIC_PRINT_MASK_VERBOSE)))
3181 				printk(KERN_INFO
3182 				       "btrfsic_submit_bio(%s) with FLUSH"
3183 				       " but dummy block already in use"
3184 				       " (ignored)!\n",
3185 				       dev_state->name);
3186 		} else {
3187 			struct btrfsic_block *const block =
3188 				&dev_state->dummy_block_for_bio_bh_flush;
3189 
3190 			block->is_iodone = 0;
3191 			block->never_written = 0;
3192 			block->iodone_w_error = 0;
3193 			block->flush_gen = dev_state->last_flush_gen + 1;
3194 			block->submit_bio_bh_rw = rw;
3195 			block->orig_bio_bh_private = bio->bi_private;
3196 			block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3197 			block->next_in_same_bio = NULL;
3198 			bio->bi_private = block;
3199 			bio->bi_end_io = btrfsic_bio_end_io;
3200 		}
3201 	}
3202 leave:
3203 	mutex_unlock(&btrfsic_mutex);
3204 
3205 	submit_bio(rw, bio);
3206 }
3207 
3208 int btrfsic_mount(struct btrfs_root *root,
3209 		  struct btrfs_fs_devices *fs_devices,
3210 		  int including_extent_data, u32 print_mask)
3211 {
3212 	int ret;
3213 	struct btrfsic_state *state;
3214 	struct list_head *dev_head = &fs_devices->devices;
3215 	struct btrfs_device *device;
3216 
3217 	if (root->nodesize != root->leafsize) {
3218 		printk(KERN_INFO
3219 		       "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
3220 		       root->nodesize, root->leafsize);
3221 		return -1;
3222 	}
3223 	if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3224 		printk(KERN_INFO
3225 		       "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3226 		       root->nodesize, (unsigned long)PAGE_CACHE_SIZE);
3227 		return -1;
3228 	}
3229 	if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3230 		printk(KERN_INFO
3231 		       "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3232 		       root->leafsize, (unsigned long)PAGE_CACHE_SIZE);
3233 		return -1;
3234 	}
3235 	if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3236 		printk(KERN_INFO
3237 		       "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3238 		       root->sectorsize, (unsigned long)PAGE_CACHE_SIZE);
3239 		return -1;
3240 	}
3241 	state = kzalloc(sizeof(*state), GFP_NOFS);
3242 	if (NULL == state) {
3243 		printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
3244 		return -1;
3245 	}
3246 
3247 	if (!btrfsic_is_initialized) {
3248 		mutex_init(&btrfsic_mutex);
3249 		btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3250 		btrfsic_is_initialized = 1;
3251 	}
3252 	mutex_lock(&btrfsic_mutex);
3253 	state->root = root;
3254 	state->print_mask = print_mask;
3255 	state->include_extent_data = including_extent_data;
3256 	state->csum_size = 0;
3257 	state->metablock_size = root->nodesize;
3258 	state->datablock_size = root->sectorsize;
3259 	INIT_LIST_HEAD(&state->all_blocks_list);
3260 	btrfsic_block_hashtable_init(&state->block_hashtable);
3261 	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3262 	state->max_superblock_generation = 0;
3263 	state->latest_superblock = NULL;
3264 
3265 	list_for_each_entry(device, dev_head, dev_list) {
3266 		struct btrfsic_dev_state *ds;
3267 		char *p;
3268 
3269 		if (!device->bdev || !device->name)
3270 			continue;
3271 
3272 		ds = btrfsic_dev_state_alloc();
3273 		if (NULL == ds) {
3274 			printk(KERN_INFO
3275 			       "btrfs check-integrity: kmalloc() failed!\n");
3276 			mutex_unlock(&btrfsic_mutex);
3277 			return -1;
3278 		}
3279 		ds->bdev = device->bdev;
3280 		ds->state = state;
3281 		bdevname(ds->bdev, ds->name);
3282 		ds->name[BDEVNAME_SIZE - 1] = '\0';
3283 		for (p = ds->name; *p != '\0'; p++);
3284 		while (p > ds->name && *p != '/')
3285 			p--;
3286 		if (*p == '/')
3287 			p++;
3288 		strlcpy(ds->name, p, sizeof(ds->name));
3289 		btrfsic_dev_state_hashtable_add(ds,
3290 						&btrfsic_dev_state_hashtable);
3291 	}
3292 
3293 	ret = btrfsic_process_superblock(state, fs_devices);
3294 	if (0 != ret) {
3295 		mutex_unlock(&btrfsic_mutex);
3296 		btrfsic_unmount(root, fs_devices);
3297 		return ret;
3298 	}
3299 
3300 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3301 		btrfsic_dump_database(state);
3302 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3303 		btrfsic_dump_tree(state);
3304 
3305 	mutex_unlock(&btrfsic_mutex);
3306 	return 0;
3307 }
3308 
3309 void btrfsic_unmount(struct btrfs_root *root,
3310 		     struct btrfs_fs_devices *fs_devices)
3311 {
3312 	struct list_head *elem_all;
3313 	struct list_head *tmp_all;
3314 	struct btrfsic_state *state;
3315 	struct list_head *dev_head = &fs_devices->devices;
3316 	struct btrfs_device *device;
3317 
3318 	if (!btrfsic_is_initialized)
3319 		return;
3320 
3321 	mutex_lock(&btrfsic_mutex);
3322 
3323 	state = NULL;
3324 	list_for_each_entry(device, dev_head, dev_list) {
3325 		struct btrfsic_dev_state *ds;
3326 
3327 		if (!device->bdev || !device->name)
3328 			continue;
3329 
3330 		ds = btrfsic_dev_state_hashtable_lookup(
3331 				device->bdev,
3332 				&btrfsic_dev_state_hashtable);
3333 		if (NULL != ds) {
3334 			state = ds->state;
3335 			btrfsic_dev_state_hashtable_remove(ds);
3336 			btrfsic_dev_state_free(ds);
3337 		}
3338 	}
3339 
3340 	if (NULL == state) {
3341 		printk(KERN_INFO
3342 		       "btrfsic: error, cannot find state information"
3343 		       " on umount!\n");
3344 		mutex_unlock(&btrfsic_mutex);
3345 		return;
3346 	}
3347 
3348 	/*
3349 	 * Don't care about keeping the lists' state up to date,
3350 	 * just free all memory that was allocated dynamically.
3351 	 * Free the blocks and the block_links.
3352 	 */
3353 	list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3354 		struct btrfsic_block *const b_all =
3355 		    list_entry(elem_all, struct btrfsic_block,
3356 			       all_blocks_node);
3357 		struct list_head *elem_ref_to;
3358 		struct list_head *tmp_ref_to;
3359 
3360 		list_for_each_safe(elem_ref_to, tmp_ref_to,
3361 				   &b_all->ref_to_list) {
3362 			struct btrfsic_block_link *const l =
3363 			    list_entry(elem_ref_to,
3364 				       struct btrfsic_block_link,
3365 				       node_ref_to);
3366 
3367 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3368 				btrfsic_print_rem_link(state, l);
3369 
3370 			l->ref_cnt--;
3371 			if (0 == l->ref_cnt)
3372 				btrfsic_block_link_free(l);
3373 		}
3374 
3375 		if (b_all->is_iodone || b_all->never_written)
3376 			btrfsic_block_free(b_all);
3377 		else
3378 			printk(KERN_INFO "btrfs: attempt to free %c-block"
3379 			       " @%llu (%s/%llu/%d) on umount which is"
3380 			       " not yet iodone!\n",
3381 			       btrfsic_get_block_type(state, b_all),
3382 			       (unsigned long long)b_all->logical_bytenr,
3383 			       b_all->dev_state->name,
3384 			       (unsigned long long)b_all->dev_bytenr,
3385 			       b_all->mirror_num);
3386 	}
3387 
3388 	mutex_unlock(&btrfsic_mutex);
3389 
3390 	kfree(state);
3391 }
3392