xref: /openbmc/linux/fs/btrfs/check-integrity.c (revision 63dc02bd)
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 a FLUSH request to the device where
41  *        these blocks are located was received and completed.
42  *    2b. All referenced blocks need to have a generation
43  *        number which is equal to the parent's number.
44  *
45  * One issue that was found using this module was that the log
46  * tree on disk became temporarily corrupted because disk blocks
47  * that had been in use for the log tree had been freed and
48  * reused too early, while being referenced by the written super
49  * block.
50  *
51  * The search term in the kernel log that can be used to filter
52  * on the existence of detected integrity issues is
53  * "btrfs: attempt".
54  *
55  * The integrity check is enabled via mount options. These
56  * mount options are only supported if the integrity check
57  * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
58  *
59  * Example #1, apply integrity checks to all metadata:
60  * mount /dev/sdb1 /mnt -o check_int
61  *
62  * Example #2, apply integrity checks to all metadata and
63  * to data extents:
64  * mount /dev/sdb1 /mnt -o check_int_data
65  *
66  * Example #3, apply integrity checks to all metadata and dump
67  * the tree that the super block references to kernel messages
68  * each time after a super block was written:
69  * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
70  *
71  * If the integrity check tool is included and activated in
72  * the mount options, plenty of kernel memory is used, and
73  * plenty of additional CPU cycles are spent. Enabling this
74  * functionality is not intended for normal use. In most
75  * cases, unless you are a btrfs developer who needs to verify
76  * the integrity of (super)-block write requests, do not
77  * enable the config option BTRFS_FS_CHECK_INTEGRITY to
78  * include and compile the integrity check tool.
79  */
80 
81 #include <linux/sched.h>
82 #include <linux/slab.h>
83 #include <linux/buffer_head.h>
84 #include <linux/mutex.h>
85 #include <linux/crc32c.h>
86 #include <linux/genhd.h>
87 #include <linux/blkdev.h>
88 #include "ctree.h"
89 #include "disk-io.h"
90 #include "transaction.h"
91 #include "extent_io.h"
92 #include "volumes.h"
93 #include "print-tree.h"
94 #include "locking.h"
95 #include "check-integrity.h"
96 
97 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
98 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
99 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
100 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
101 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
102 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
103 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
104 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)	/* in characters,
105 							 * excluding " [...]" */
106 #define BTRFSIC_BLOCK_SIZE PAGE_SIZE
107 
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:2;	/* 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 *data;
214 	struct buffer_head *bh;	/* do not use if set to NULL */
215 };
216 
217 /* This structure is used to implement recursion without occupying
218  * any stack space, refer to btrfsic_process_metablock() */
219 struct btrfsic_stack_frame {
220 	u32 magic;
221 	u32 nr;
222 	int error;
223 	int i;
224 	int limit_nesting;
225 	int num_copies;
226 	int mirror_num;
227 	struct btrfsic_block *block;
228 	struct btrfsic_block_data_ctx *block_ctx;
229 	struct btrfsic_block *next_block;
230 	struct btrfsic_block_data_ctx next_block_ctx;
231 	struct btrfs_header *hdr;
232 	struct btrfsic_stack_frame *prev;
233 };
234 
235 /* Some state per mounted filesystem */
236 struct btrfsic_state {
237 	u32 print_mask;
238 	int include_extent_data;
239 	int csum_size;
240 	struct list_head all_blocks_list;
241 	struct btrfsic_block_hashtable block_hashtable;
242 	struct btrfsic_block_link_hashtable block_link_hashtable;
243 	struct btrfs_root *root;
244 	u64 max_superblock_generation;
245 	struct btrfsic_block *latest_superblock;
246 };
247 
248 static void btrfsic_block_init(struct btrfsic_block *b);
249 static struct btrfsic_block *btrfsic_block_alloc(void);
250 static void btrfsic_block_free(struct btrfsic_block *b);
251 static void btrfsic_block_link_init(struct btrfsic_block_link *n);
252 static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
253 static void btrfsic_block_link_free(struct btrfsic_block_link *n);
254 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
255 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
256 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
257 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
258 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
259 					struct btrfsic_block_hashtable *h);
260 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
261 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
262 		struct block_device *bdev,
263 		u64 dev_bytenr,
264 		struct btrfsic_block_hashtable *h);
265 static void btrfsic_block_link_hashtable_init(
266 		struct btrfsic_block_link_hashtable *h);
267 static void btrfsic_block_link_hashtable_add(
268 		struct btrfsic_block_link *l,
269 		struct btrfsic_block_link_hashtable *h);
270 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
271 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
272 		struct block_device *bdev_ref_to,
273 		u64 dev_bytenr_ref_to,
274 		struct block_device *bdev_ref_from,
275 		u64 dev_bytenr_ref_from,
276 		struct btrfsic_block_link_hashtable *h);
277 static void btrfsic_dev_state_hashtable_init(
278 		struct btrfsic_dev_state_hashtable *h);
279 static void btrfsic_dev_state_hashtable_add(
280 		struct btrfsic_dev_state *ds,
281 		struct btrfsic_dev_state_hashtable *h);
282 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
283 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
284 		struct block_device *bdev,
285 		struct btrfsic_dev_state_hashtable *h);
286 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
287 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
288 static int btrfsic_process_superblock(struct btrfsic_state *state,
289 				      struct btrfs_fs_devices *fs_devices);
290 static int btrfsic_process_metablock(struct btrfsic_state *state,
291 				     struct btrfsic_block *block,
292 				     struct btrfsic_block_data_ctx *block_ctx,
293 				     struct btrfs_header *hdr,
294 				     int limit_nesting, int force_iodone_flag);
295 static int btrfsic_create_link_to_next_block(
296 		struct btrfsic_state *state,
297 		struct btrfsic_block *block,
298 		struct btrfsic_block_data_ctx
299 		*block_ctx, u64 next_bytenr,
300 		int limit_nesting,
301 		struct btrfsic_block_data_ctx *next_block_ctx,
302 		struct btrfsic_block **next_blockp,
303 		int force_iodone_flag,
304 		int *num_copiesp, int *mirror_nump,
305 		struct btrfs_disk_key *disk_key,
306 		u64 parent_generation);
307 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
308 				      struct btrfsic_block *block,
309 				      struct btrfsic_block_data_ctx *block_ctx,
310 				      u32 item_offset, int force_iodone_flag);
311 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
312 			     struct btrfsic_block_data_ctx *block_ctx_out,
313 			     int mirror_num);
314 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
315 				  u32 len, struct block_device *bdev,
316 				  struct btrfsic_block_data_ctx *block_ctx_out);
317 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
318 static int btrfsic_read_block(struct btrfsic_state *state,
319 			      struct btrfsic_block_data_ctx *block_ctx);
320 static void btrfsic_dump_database(struct btrfsic_state *state);
321 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
322 				     const u8 *data, unsigned int size);
323 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
324 					  u64 dev_bytenr, u8 *mapped_data,
325 					  unsigned int len, struct bio *bio,
326 					  int *bio_is_patched,
327 					  struct buffer_head *bh,
328 					  int submit_bio_bh_rw);
329 static int btrfsic_process_written_superblock(
330 		struct btrfsic_state *state,
331 		struct btrfsic_block *const block,
332 		struct btrfs_super_block *const super_hdr);
333 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
334 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
335 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
336 					      const struct btrfsic_block *block,
337 					      int recursion_level);
338 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
339 					struct btrfsic_block *const block,
340 					int recursion_level);
341 static void btrfsic_print_add_link(const struct btrfsic_state *state,
342 				   const struct btrfsic_block_link *l);
343 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
344 				   const struct btrfsic_block_link *l);
345 static char btrfsic_get_block_type(const struct btrfsic_state *state,
346 				   const struct btrfsic_block *block);
347 static void btrfsic_dump_tree(const struct btrfsic_state *state);
348 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
349 				  const struct btrfsic_block *block,
350 				  int indent_level);
351 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
352 		struct btrfsic_state *state,
353 		struct btrfsic_block_data_ctx *next_block_ctx,
354 		struct btrfsic_block *next_block,
355 		struct btrfsic_block *from_block,
356 		u64 parent_generation);
357 static struct btrfsic_block *btrfsic_block_lookup_or_add(
358 		struct btrfsic_state *state,
359 		struct btrfsic_block_data_ctx *block_ctx,
360 		const char *additional_string,
361 		int is_metadata,
362 		int is_iodone,
363 		int never_written,
364 		int mirror_num,
365 		int *was_created);
366 static int btrfsic_process_superblock_dev_mirror(
367 		struct btrfsic_state *state,
368 		struct btrfsic_dev_state *dev_state,
369 		struct btrfs_device *device,
370 		int superblock_mirror_num,
371 		struct btrfsic_dev_state **selected_dev_state,
372 		struct btrfs_super_block *selected_super);
373 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
374 		struct block_device *bdev);
375 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
376 					   u64 bytenr,
377 					   struct btrfsic_dev_state *dev_state,
378 					   u64 dev_bytenr, char *data);
379 
380 static struct mutex btrfsic_mutex;
381 static int btrfsic_is_initialized;
382 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
383 
384 
385 static void btrfsic_block_init(struct btrfsic_block *b)
386 {
387 	b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
388 	b->dev_state = NULL;
389 	b->dev_bytenr = 0;
390 	b->logical_bytenr = 0;
391 	b->generation = BTRFSIC_GENERATION_UNKNOWN;
392 	b->disk_key.objectid = 0;
393 	b->disk_key.type = 0;
394 	b->disk_key.offset = 0;
395 	b->is_metadata = 0;
396 	b->is_superblock = 0;
397 	b->is_iodone = 0;
398 	b->iodone_w_error = 0;
399 	b->never_written = 0;
400 	b->mirror_num = 0;
401 	b->next_in_same_bio = NULL;
402 	b->orig_bio_bh_private = NULL;
403 	b->orig_bio_bh_end_io.bio = NULL;
404 	INIT_LIST_HEAD(&b->collision_resolving_node);
405 	INIT_LIST_HEAD(&b->all_blocks_node);
406 	INIT_LIST_HEAD(&b->ref_to_list);
407 	INIT_LIST_HEAD(&b->ref_from_list);
408 	b->submit_bio_bh_rw = 0;
409 	b->flush_gen = 0;
410 }
411 
412 static struct btrfsic_block *btrfsic_block_alloc(void)
413 {
414 	struct btrfsic_block *b;
415 
416 	b = kzalloc(sizeof(*b), GFP_NOFS);
417 	if (NULL != b)
418 		btrfsic_block_init(b);
419 
420 	return b;
421 }
422 
423 static void btrfsic_block_free(struct btrfsic_block *b)
424 {
425 	BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
426 	kfree(b);
427 }
428 
429 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
430 {
431 	l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
432 	l->ref_cnt = 1;
433 	INIT_LIST_HEAD(&l->node_ref_to);
434 	INIT_LIST_HEAD(&l->node_ref_from);
435 	INIT_LIST_HEAD(&l->collision_resolving_node);
436 	l->block_ref_to = NULL;
437 	l->block_ref_from = NULL;
438 }
439 
440 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
441 {
442 	struct btrfsic_block_link *l;
443 
444 	l = kzalloc(sizeof(*l), GFP_NOFS);
445 	if (NULL != l)
446 		btrfsic_block_link_init(l);
447 
448 	return l;
449 }
450 
451 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
452 {
453 	BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
454 	kfree(l);
455 }
456 
457 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
458 {
459 	ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
460 	ds->bdev = NULL;
461 	ds->state = NULL;
462 	ds->name[0] = '\0';
463 	INIT_LIST_HEAD(&ds->collision_resolving_node);
464 	ds->last_flush_gen = 0;
465 	btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
466 	ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
467 	ds->dummy_block_for_bio_bh_flush.dev_state = ds;
468 }
469 
470 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
471 {
472 	struct btrfsic_dev_state *ds;
473 
474 	ds = kzalloc(sizeof(*ds), GFP_NOFS);
475 	if (NULL != ds)
476 		btrfsic_dev_state_init(ds);
477 
478 	return ds;
479 }
480 
481 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
482 {
483 	BUG_ON(!(NULL == ds ||
484 		 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
485 	kfree(ds);
486 }
487 
488 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
489 {
490 	int i;
491 
492 	for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
493 		INIT_LIST_HEAD(h->table + i);
494 }
495 
496 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
497 					struct btrfsic_block_hashtable *h)
498 {
499 	const unsigned int hashval =
500 	    (((unsigned int)(b->dev_bytenr >> 16)) ^
501 	     ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
502 	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
503 
504 	list_add(&b->collision_resolving_node, h->table + hashval);
505 }
506 
507 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
508 {
509 	list_del(&b->collision_resolving_node);
510 }
511 
512 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
513 		struct block_device *bdev,
514 		u64 dev_bytenr,
515 		struct btrfsic_block_hashtable *h)
516 {
517 	const unsigned int hashval =
518 	    (((unsigned int)(dev_bytenr >> 16)) ^
519 	     ((unsigned int)((uintptr_t)bdev))) &
520 	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
521 	struct list_head *elem;
522 
523 	list_for_each(elem, h->table + hashval) {
524 		struct btrfsic_block *const b =
525 		    list_entry(elem, struct btrfsic_block,
526 			       collision_resolving_node);
527 
528 		if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
529 			return b;
530 	}
531 
532 	return NULL;
533 }
534 
535 static void btrfsic_block_link_hashtable_init(
536 		struct btrfsic_block_link_hashtable *h)
537 {
538 	int i;
539 
540 	for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
541 		INIT_LIST_HEAD(h->table + i);
542 }
543 
544 static void btrfsic_block_link_hashtable_add(
545 		struct btrfsic_block_link *l,
546 		struct btrfsic_block_link_hashtable *h)
547 {
548 	const unsigned int hashval =
549 	    (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
550 	     ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
551 	     ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
552 	     ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
553 	     & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
554 
555 	BUG_ON(NULL == l->block_ref_to);
556 	BUG_ON(NULL == l->block_ref_from);
557 	list_add(&l->collision_resolving_node, h->table + hashval);
558 }
559 
560 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
561 {
562 	list_del(&l->collision_resolving_node);
563 }
564 
565 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
566 		struct block_device *bdev_ref_to,
567 		u64 dev_bytenr_ref_to,
568 		struct block_device *bdev_ref_from,
569 		u64 dev_bytenr_ref_from,
570 		struct btrfsic_block_link_hashtable *h)
571 {
572 	const unsigned int hashval =
573 	    (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
574 	     ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
575 	     ((unsigned int)((uintptr_t)bdev_ref_to)) ^
576 	     ((unsigned int)((uintptr_t)bdev_ref_from))) &
577 	     (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
578 	struct list_head *elem;
579 
580 	list_for_each(elem, h->table + hashval) {
581 		struct btrfsic_block_link *const l =
582 		    list_entry(elem, struct btrfsic_block_link,
583 			       collision_resolving_node);
584 
585 		BUG_ON(NULL == l->block_ref_to);
586 		BUG_ON(NULL == l->block_ref_from);
587 		if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
588 		    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
589 		    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
590 		    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
591 			return l;
592 	}
593 
594 	return NULL;
595 }
596 
597 static void btrfsic_dev_state_hashtable_init(
598 		struct btrfsic_dev_state_hashtable *h)
599 {
600 	int i;
601 
602 	for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
603 		INIT_LIST_HEAD(h->table + i);
604 }
605 
606 static void btrfsic_dev_state_hashtable_add(
607 		struct btrfsic_dev_state *ds,
608 		struct btrfsic_dev_state_hashtable *h)
609 {
610 	const unsigned int hashval =
611 	    (((unsigned int)((uintptr_t)ds->bdev)) &
612 	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
613 
614 	list_add(&ds->collision_resolving_node, h->table + hashval);
615 }
616 
617 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
618 {
619 	list_del(&ds->collision_resolving_node);
620 }
621 
622 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
623 		struct block_device *bdev,
624 		struct btrfsic_dev_state_hashtable *h)
625 {
626 	const unsigned int hashval =
627 	    (((unsigned int)((uintptr_t)bdev)) &
628 	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
629 	struct list_head *elem;
630 
631 	list_for_each(elem, h->table + hashval) {
632 		struct btrfsic_dev_state *const ds =
633 		    list_entry(elem, struct btrfsic_dev_state,
634 			       collision_resolving_node);
635 
636 		if (ds->bdev == bdev)
637 			return ds;
638 	}
639 
640 	return NULL;
641 }
642 
643 static int btrfsic_process_superblock(struct btrfsic_state *state,
644 				      struct btrfs_fs_devices *fs_devices)
645 {
646 	int ret = 0;
647 	struct btrfs_super_block *selected_super;
648 	struct list_head *dev_head = &fs_devices->devices;
649 	struct btrfs_device *device;
650 	struct btrfsic_dev_state *selected_dev_state = NULL;
651 	int pass;
652 
653 	BUG_ON(NULL == state);
654 	selected_super = kmalloc(sizeof(*selected_super), GFP_NOFS);
655 	if (NULL == selected_super) {
656 		printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
657 		return -1;
658 	}
659 
660 	list_for_each_entry(device, dev_head, dev_list) {
661 		int i;
662 		struct btrfsic_dev_state *dev_state;
663 
664 		if (!device->bdev || !device->name)
665 			continue;
666 
667 		dev_state = btrfsic_dev_state_lookup(device->bdev);
668 		BUG_ON(NULL == dev_state);
669 		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
670 			ret = btrfsic_process_superblock_dev_mirror(
671 					state, dev_state, device, i,
672 					&selected_dev_state, selected_super);
673 			if (0 != ret && 0 == i) {
674 				kfree(selected_super);
675 				return ret;
676 			}
677 		}
678 	}
679 
680 	if (NULL == state->latest_superblock) {
681 		printk(KERN_INFO "btrfsic: no superblock found!\n");
682 		kfree(selected_super);
683 		return -1;
684 	}
685 
686 	state->csum_size = btrfs_super_csum_size(selected_super);
687 
688 	for (pass = 0; pass < 3; pass++) {
689 		int num_copies;
690 		int mirror_num;
691 		u64 next_bytenr;
692 
693 		switch (pass) {
694 		case 0:
695 			next_bytenr = btrfs_super_root(selected_super);
696 			if (state->print_mask &
697 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
698 				printk(KERN_INFO "root@%llu\n",
699 				       (unsigned long long)next_bytenr);
700 			break;
701 		case 1:
702 			next_bytenr = btrfs_super_chunk_root(selected_super);
703 			if (state->print_mask &
704 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
705 				printk(KERN_INFO "chunk@%llu\n",
706 				       (unsigned long long)next_bytenr);
707 			break;
708 		case 2:
709 			next_bytenr = btrfs_super_log_root(selected_super);
710 			if (0 == next_bytenr)
711 				continue;
712 			if (state->print_mask &
713 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
714 				printk(KERN_INFO "log@%llu\n",
715 				       (unsigned long long)next_bytenr);
716 			break;
717 		}
718 
719 		num_copies =
720 		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
721 				     next_bytenr, PAGE_SIZE);
722 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
723 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
724 			       (unsigned long long)next_bytenr, num_copies);
725 
726 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
727 			struct btrfsic_block *next_block;
728 			struct btrfsic_block_data_ctx tmp_next_block_ctx;
729 			struct btrfsic_block_link *l;
730 			struct btrfs_header *hdr;
731 
732 			ret = btrfsic_map_block(state, next_bytenr, PAGE_SIZE,
733 						&tmp_next_block_ctx,
734 						mirror_num);
735 			if (ret) {
736 				printk(KERN_INFO "btrfsic:"
737 				       " btrfsic_map_block(root @%llu,"
738 				       " mirror %d) failed!\n",
739 				       (unsigned long long)next_bytenr,
740 				       mirror_num);
741 				kfree(selected_super);
742 				return -1;
743 			}
744 
745 			next_block = btrfsic_block_hashtable_lookup(
746 					tmp_next_block_ctx.dev->bdev,
747 					tmp_next_block_ctx.dev_bytenr,
748 					&state->block_hashtable);
749 			BUG_ON(NULL == next_block);
750 
751 			l = btrfsic_block_link_hashtable_lookup(
752 					tmp_next_block_ctx.dev->bdev,
753 					tmp_next_block_ctx.dev_bytenr,
754 					state->latest_superblock->dev_state->
755 					bdev,
756 					state->latest_superblock->dev_bytenr,
757 					&state->block_link_hashtable);
758 			BUG_ON(NULL == l);
759 
760 			ret = btrfsic_read_block(state, &tmp_next_block_ctx);
761 			if (ret < (int)BTRFSIC_BLOCK_SIZE) {
762 				printk(KERN_INFO
763 				       "btrfsic: read @logical %llu failed!\n",
764 				       (unsigned long long)
765 				       tmp_next_block_ctx.start);
766 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
767 				kfree(selected_super);
768 				return -1;
769 			}
770 
771 			hdr = (struct btrfs_header *)tmp_next_block_ctx.data;
772 			ret = btrfsic_process_metablock(state,
773 							next_block,
774 							&tmp_next_block_ctx,
775 							hdr,
776 							BTRFS_MAX_LEVEL + 3, 1);
777 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
778 		}
779 	}
780 
781 	kfree(selected_super);
782 	return ret;
783 }
784 
785 static int btrfsic_process_superblock_dev_mirror(
786 		struct btrfsic_state *state,
787 		struct btrfsic_dev_state *dev_state,
788 		struct btrfs_device *device,
789 		int superblock_mirror_num,
790 		struct btrfsic_dev_state **selected_dev_state,
791 		struct btrfs_super_block *selected_super)
792 {
793 	struct btrfs_super_block *super_tmp;
794 	u64 dev_bytenr;
795 	struct buffer_head *bh;
796 	struct btrfsic_block *superblock_tmp;
797 	int pass;
798 	struct block_device *const superblock_bdev = device->bdev;
799 
800 	/* super block bytenr is always the unmapped device bytenr */
801 	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
802 	bh = __bread(superblock_bdev, dev_bytenr / 4096, 4096);
803 	if (NULL == bh)
804 		return -1;
805 	super_tmp = (struct btrfs_super_block *)
806 	    (bh->b_data + (dev_bytenr & 4095));
807 
808 	if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
809 	    strncmp((char *)(&(super_tmp->magic)), BTRFS_MAGIC,
810 		    sizeof(super_tmp->magic)) ||
811 	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE)) {
812 		brelse(bh);
813 		return 0;
814 	}
815 
816 	superblock_tmp =
817 	    btrfsic_block_hashtable_lookup(superblock_bdev,
818 					   dev_bytenr,
819 					   &state->block_hashtable);
820 	if (NULL == superblock_tmp) {
821 		superblock_tmp = btrfsic_block_alloc();
822 		if (NULL == superblock_tmp) {
823 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
824 			brelse(bh);
825 			return -1;
826 		}
827 		/* for superblock, only the dev_bytenr makes sense */
828 		superblock_tmp->dev_bytenr = dev_bytenr;
829 		superblock_tmp->dev_state = dev_state;
830 		superblock_tmp->logical_bytenr = dev_bytenr;
831 		superblock_tmp->generation = btrfs_super_generation(super_tmp);
832 		superblock_tmp->is_metadata = 1;
833 		superblock_tmp->is_superblock = 1;
834 		superblock_tmp->is_iodone = 1;
835 		superblock_tmp->never_written = 0;
836 		superblock_tmp->mirror_num = 1 + superblock_mirror_num;
837 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
838 			printk(KERN_INFO "New initial S-block (bdev %p, %s)"
839 			       " @%llu (%s/%llu/%d)\n",
840 			       superblock_bdev, device->name,
841 			       (unsigned long long)dev_bytenr,
842 			       dev_state->name,
843 			       (unsigned long long)dev_bytenr,
844 			       superblock_mirror_num);
845 		list_add(&superblock_tmp->all_blocks_node,
846 			 &state->all_blocks_list);
847 		btrfsic_block_hashtable_add(superblock_tmp,
848 					    &state->block_hashtable);
849 	}
850 
851 	/* select the one with the highest generation field */
852 	if (btrfs_super_generation(super_tmp) >
853 	    state->max_superblock_generation ||
854 	    0 == state->max_superblock_generation) {
855 		memcpy(selected_super, super_tmp, sizeof(*selected_super));
856 		*selected_dev_state = dev_state;
857 		state->max_superblock_generation =
858 		    btrfs_super_generation(super_tmp);
859 		state->latest_superblock = superblock_tmp;
860 	}
861 
862 	for (pass = 0; pass < 3; pass++) {
863 		u64 next_bytenr;
864 		int num_copies;
865 		int mirror_num;
866 		const char *additional_string = NULL;
867 		struct btrfs_disk_key tmp_disk_key;
868 
869 		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
870 		tmp_disk_key.offset = 0;
871 		switch (pass) {
872 		case 0:
873 			tmp_disk_key.objectid =
874 			    cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
875 			additional_string = "initial root ";
876 			next_bytenr = btrfs_super_root(super_tmp);
877 			break;
878 		case 1:
879 			tmp_disk_key.objectid =
880 			    cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
881 			additional_string = "initial chunk ";
882 			next_bytenr = btrfs_super_chunk_root(super_tmp);
883 			break;
884 		case 2:
885 			tmp_disk_key.objectid =
886 			    cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
887 			additional_string = "initial log ";
888 			next_bytenr = btrfs_super_log_root(super_tmp);
889 			if (0 == next_bytenr)
890 				continue;
891 			break;
892 		}
893 
894 		num_copies =
895 		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
896 				     next_bytenr, PAGE_SIZE);
897 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
898 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
899 			       (unsigned long long)next_bytenr, num_copies);
900 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
901 			struct btrfsic_block *next_block;
902 			struct btrfsic_block_data_ctx tmp_next_block_ctx;
903 			struct btrfsic_block_link *l;
904 
905 			if (btrfsic_map_block(state, next_bytenr, PAGE_SIZE,
906 					      &tmp_next_block_ctx,
907 					      mirror_num)) {
908 				printk(KERN_INFO "btrfsic: btrfsic_map_block("
909 				       "bytenr @%llu, mirror %d) failed!\n",
910 				       (unsigned long long)next_bytenr,
911 				       mirror_num);
912 				brelse(bh);
913 				return -1;
914 			}
915 
916 			next_block = btrfsic_block_lookup_or_add(
917 					state, &tmp_next_block_ctx,
918 					additional_string, 1, 1, 0,
919 					mirror_num, NULL);
920 			if (NULL == next_block) {
921 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
922 				brelse(bh);
923 				return -1;
924 			}
925 
926 			next_block->disk_key = tmp_disk_key;
927 			next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
928 			l = btrfsic_block_link_lookup_or_add(
929 					state, &tmp_next_block_ctx,
930 					next_block, superblock_tmp,
931 					BTRFSIC_GENERATION_UNKNOWN);
932 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
933 			if (NULL == l) {
934 				brelse(bh);
935 				return -1;
936 			}
937 		}
938 	}
939 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
940 		btrfsic_dump_tree_sub(state, superblock_tmp, 0);
941 
942 	brelse(bh);
943 	return 0;
944 }
945 
946 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
947 {
948 	struct btrfsic_stack_frame *sf;
949 
950 	sf = kzalloc(sizeof(*sf), GFP_NOFS);
951 	if (NULL == sf)
952 		printk(KERN_INFO "btrfsic: alloc memory failed!\n");
953 	else
954 		sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
955 	return sf;
956 }
957 
958 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
959 {
960 	BUG_ON(!(NULL == sf ||
961 		 BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
962 	kfree(sf);
963 }
964 
965 static int btrfsic_process_metablock(
966 		struct btrfsic_state *state,
967 		struct btrfsic_block *const first_block,
968 		struct btrfsic_block_data_ctx *const first_block_ctx,
969 		struct btrfs_header *const first_hdr,
970 		int first_limit_nesting, int force_iodone_flag)
971 {
972 	struct btrfsic_stack_frame initial_stack_frame = { 0 };
973 	struct btrfsic_stack_frame *sf;
974 	struct btrfsic_stack_frame *next_stack;
975 
976 	sf = &initial_stack_frame;
977 	sf->error = 0;
978 	sf->i = -1;
979 	sf->limit_nesting = first_limit_nesting;
980 	sf->block = first_block;
981 	sf->block_ctx = first_block_ctx;
982 	sf->next_block = NULL;
983 	sf->hdr = first_hdr;
984 	sf->prev = NULL;
985 
986 continue_with_new_stack_frame:
987 	sf->block->generation = le64_to_cpu(sf->hdr->generation);
988 	if (0 == sf->hdr->level) {
989 		struct btrfs_leaf *const leafhdr =
990 		    (struct btrfs_leaf *)sf->hdr;
991 
992 		if (-1 == sf->i) {
993 			sf->nr = le32_to_cpu(leafhdr->header.nritems);
994 
995 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
996 				printk(KERN_INFO
997 				       "leaf %llu items %d generation %llu"
998 				       " owner %llu\n",
999 				       (unsigned long long)
1000 				       sf->block_ctx->start,
1001 				       sf->nr,
1002 				       (unsigned long long)
1003 				       le64_to_cpu(leafhdr->header.generation),
1004 				       (unsigned long long)
1005 				       le64_to_cpu(leafhdr->header.owner));
1006 		}
1007 
1008 continue_with_current_leaf_stack_frame:
1009 		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1010 			sf->i++;
1011 			sf->num_copies = 0;
1012 		}
1013 
1014 		if (sf->i < sf->nr) {
1015 			struct btrfs_item *disk_item = leafhdr->items + sf->i;
1016 			struct btrfs_disk_key *disk_key = &disk_item->key;
1017 			u8 type;
1018 			const u32 item_offset = le32_to_cpu(disk_item->offset);
1019 
1020 			type = disk_key->type;
1021 
1022 			if (BTRFS_ROOT_ITEM_KEY == type) {
1023 				const struct btrfs_root_item *const root_item =
1024 				    (struct btrfs_root_item *)
1025 				    (sf->block_ctx->data +
1026 				     offsetof(struct btrfs_leaf, items) +
1027 				     item_offset);
1028 				const u64 next_bytenr =
1029 				    le64_to_cpu(root_item->bytenr);
1030 
1031 				sf->error =
1032 				    btrfsic_create_link_to_next_block(
1033 						state,
1034 						sf->block,
1035 						sf->block_ctx,
1036 						next_bytenr,
1037 						sf->limit_nesting,
1038 						&sf->next_block_ctx,
1039 						&sf->next_block,
1040 						force_iodone_flag,
1041 						&sf->num_copies,
1042 						&sf->mirror_num,
1043 						disk_key,
1044 						le64_to_cpu(root_item->
1045 						generation));
1046 				if (sf->error)
1047 					goto one_stack_frame_backwards;
1048 
1049 				if (NULL != sf->next_block) {
1050 					struct btrfs_header *const next_hdr =
1051 					    (struct btrfs_header *)
1052 					    sf->next_block_ctx.data;
1053 
1054 					next_stack =
1055 					    btrfsic_stack_frame_alloc();
1056 					if (NULL == next_stack) {
1057 						btrfsic_release_block_ctx(
1058 								&sf->
1059 								next_block_ctx);
1060 						goto one_stack_frame_backwards;
1061 					}
1062 
1063 					next_stack->i = -1;
1064 					next_stack->block = sf->next_block;
1065 					next_stack->block_ctx =
1066 					    &sf->next_block_ctx;
1067 					next_stack->next_block = NULL;
1068 					next_stack->hdr = next_hdr;
1069 					next_stack->limit_nesting =
1070 					    sf->limit_nesting - 1;
1071 					next_stack->prev = sf;
1072 					sf = next_stack;
1073 					goto continue_with_new_stack_frame;
1074 				}
1075 			} else if (BTRFS_EXTENT_DATA_KEY == type &&
1076 				   state->include_extent_data) {
1077 				sf->error = btrfsic_handle_extent_data(
1078 						state,
1079 						sf->block,
1080 						sf->block_ctx,
1081 						item_offset,
1082 						force_iodone_flag);
1083 				if (sf->error)
1084 					goto one_stack_frame_backwards;
1085 			}
1086 
1087 			goto continue_with_current_leaf_stack_frame;
1088 		}
1089 	} else {
1090 		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1091 
1092 		if (-1 == sf->i) {
1093 			sf->nr = le32_to_cpu(nodehdr->header.nritems);
1094 
1095 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1096 				printk(KERN_INFO "node %llu level %d items %d"
1097 				       " generation %llu owner %llu\n",
1098 				       (unsigned long long)
1099 				       sf->block_ctx->start,
1100 				       nodehdr->header.level, sf->nr,
1101 				       (unsigned long long)
1102 				       le64_to_cpu(nodehdr->header.generation),
1103 				       (unsigned long long)
1104 				       le64_to_cpu(nodehdr->header.owner));
1105 		}
1106 
1107 continue_with_current_node_stack_frame:
1108 		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1109 			sf->i++;
1110 			sf->num_copies = 0;
1111 		}
1112 
1113 		if (sf->i < sf->nr) {
1114 			struct btrfs_key_ptr *disk_key_ptr =
1115 			    nodehdr->ptrs + sf->i;
1116 			const u64 next_bytenr =
1117 			    le64_to_cpu(disk_key_ptr->blockptr);
1118 
1119 			sf->error = btrfsic_create_link_to_next_block(
1120 					state,
1121 					sf->block,
1122 					sf->block_ctx,
1123 					next_bytenr,
1124 					sf->limit_nesting,
1125 					&sf->next_block_ctx,
1126 					&sf->next_block,
1127 					force_iodone_flag,
1128 					&sf->num_copies,
1129 					&sf->mirror_num,
1130 					&disk_key_ptr->key,
1131 					le64_to_cpu(disk_key_ptr->generation));
1132 			if (sf->error)
1133 				goto one_stack_frame_backwards;
1134 
1135 			if (NULL != sf->next_block) {
1136 				struct btrfs_header *const next_hdr =
1137 				    (struct btrfs_header *)
1138 				    sf->next_block_ctx.data;
1139 
1140 				next_stack = btrfsic_stack_frame_alloc();
1141 				if (NULL == next_stack)
1142 					goto one_stack_frame_backwards;
1143 
1144 				next_stack->i = -1;
1145 				next_stack->block = sf->next_block;
1146 				next_stack->block_ctx = &sf->next_block_ctx;
1147 				next_stack->next_block = NULL;
1148 				next_stack->hdr = next_hdr;
1149 				next_stack->limit_nesting =
1150 				    sf->limit_nesting - 1;
1151 				next_stack->prev = sf;
1152 				sf = next_stack;
1153 				goto continue_with_new_stack_frame;
1154 			}
1155 
1156 			goto continue_with_current_node_stack_frame;
1157 		}
1158 	}
1159 
1160 one_stack_frame_backwards:
1161 	if (NULL != sf->prev) {
1162 		struct btrfsic_stack_frame *const prev = sf->prev;
1163 
1164 		/* the one for the initial block is freed in the caller */
1165 		btrfsic_release_block_ctx(sf->block_ctx);
1166 
1167 		if (sf->error) {
1168 			prev->error = sf->error;
1169 			btrfsic_stack_frame_free(sf);
1170 			sf = prev;
1171 			goto one_stack_frame_backwards;
1172 		}
1173 
1174 		btrfsic_stack_frame_free(sf);
1175 		sf = prev;
1176 		goto continue_with_new_stack_frame;
1177 	} else {
1178 		BUG_ON(&initial_stack_frame != sf);
1179 	}
1180 
1181 	return sf->error;
1182 }
1183 
1184 static int btrfsic_create_link_to_next_block(
1185 		struct btrfsic_state *state,
1186 		struct btrfsic_block *block,
1187 		struct btrfsic_block_data_ctx *block_ctx,
1188 		u64 next_bytenr,
1189 		int limit_nesting,
1190 		struct btrfsic_block_data_ctx *next_block_ctx,
1191 		struct btrfsic_block **next_blockp,
1192 		int force_iodone_flag,
1193 		int *num_copiesp, int *mirror_nump,
1194 		struct btrfs_disk_key *disk_key,
1195 		u64 parent_generation)
1196 {
1197 	struct btrfsic_block *next_block = NULL;
1198 	int ret;
1199 	struct btrfsic_block_link *l;
1200 	int did_alloc_block_link;
1201 	int block_was_created;
1202 
1203 	*next_blockp = NULL;
1204 	if (0 == *num_copiesp) {
1205 		*num_copiesp =
1206 		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
1207 				     next_bytenr, PAGE_SIZE);
1208 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1209 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1210 			       (unsigned long long)next_bytenr, *num_copiesp);
1211 		*mirror_nump = 1;
1212 	}
1213 
1214 	if (*mirror_nump > *num_copiesp)
1215 		return 0;
1216 
1217 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1218 		printk(KERN_INFO
1219 		       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1220 		       *mirror_nump);
1221 	ret = btrfsic_map_block(state, next_bytenr,
1222 				BTRFSIC_BLOCK_SIZE,
1223 				next_block_ctx, *mirror_nump);
1224 	if (ret) {
1225 		printk(KERN_INFO
1226 		       "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1227 		       (unsigned long long)next_bytenr, *mirror_nump);
1228 		btrfsic_release_block_ctx(next_block_ctx);
1229 		*next_blockp = NULL;
1230 		return -1;
1231 	}
1232 
1233 	next_block = btrfsic_block_lookup_or_add(state,
1234 						 next_block_ctx, "referenced ",
1235 						 1, force_iodone_flag,
1236 						 !force_iodone_flag,
1237 						 *mirror_nump,
1238 						 &block_was_created);
1239 	if (NULL == next_block) {
1240 		btrfsic_release_block_ctx(next_block_ctx);
1241 		*next_blockp = NULL;
1242 		return -1;
1243 	}
1244 	if (block_was_created) {
1245 		l = NULL;
1246 		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1247 	} else {
1248 		if (next_block->logical_bytenr != next_bytenr &&
1249 		    !(!next_block->is_metadata &&
1250 		      0 == next_block->logical_bytenr)) {
1251 			printk(KERN_INFO
1252 			       "Referenced block @%llu (%s/%llu/%d)"
1253 			       " found in hash table, %c,"
1254 			       " bytenr mismatch (!= stored %llu).\n",
1255 			       (unsigned long long)next_bytenr,
1256 			       next_block_ctx->dev->name,
1257 			       (unsigned long long)next_block_ctx->dev_bytenr,
1258 			       *mirror_nump,
1259 			       btrfsic_get_block_type(state, next_block),
1260 			       (unsigned long long)next_block->logical_bytenr);
1261 		} else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1262 			printk(KERN_INFO
1263 			       "Referenced block @%llu (%s/%llu/%d)"
1264 			       " found in hash table, %c.\n",
1265 			       (unsigned long long)next_bytenr,
1266 			       next_block_ctx->dev->name,
1267 			       (unsigned long long)next_block_ctx->dev_bytenr,
1268 			       *mirror_nump,
1269 			       btrfsic_get_block_type(state, next_block));
1270 		next_block->logical_bytenr = next_bytenr;
1271 
1272 		next_block->mirror_num = *mirror_nump;
1273 		l = btrfsic_block_link_hashtable_lookup(
1274 				next_block_ctx->dev->bdev,
1275 				next_block_ctx->dev_bytenr,
1276 				block_ctx->dev->bdev,
1277 				block_ctx->dev_bytenr,
1278 				&state->block_link_hashtable);
1279 	}
1280 
1281 	next_block->disk_key = *disk_key;
1282 	if (NULL == l) {
1283 		l = btrfsic_block_link_alloc();
1284 		if (NULL == l) {
1285 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1286 			btrfsic_release_block_ctx(next_block_ctx);
1287 			*next_blockp = NULL;
1288 			return -1;
1289 		}
1290 
1291 		did_alloc_block_link = 1;
1292 		l->block_ref_to = next_block;
1293 		l->block_ref_from = block;
1294 		l->ref_cnt = 1;
1295 		l->parent_generation = parent_generation;
1296 
1297 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1298 			btrfsic_print_add_link(state, l);
1299 
1300 		list_add(&l->node_ref_to, &block->ref_to_list);
1301 		list_add(&l->node_ref_from, &next_block->ref_from_list);
1302 
1303 		btrfsic_block_link_hashtable_add(l,
1304 						 &state->block_link_hashtable);
1305 	} else {
1306 		did_alloc_block_link = 0;
1307 		if (0 == limit_nesting) {
1308 			l->ref_cnt++;
1309 			l->parent_generation = parent_generation;
1310 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1311 				btrfsic_print_add_link(state, l);
1312 		}
1313 	}
1314 
1315 	if (limit_nesting > 0 && did_alloc_block_link) {
1316 		ret = btrfsic_read_block(state, next_block_ctx);
1317 		if (ret < (int)BTRFSIC_BLOCK_SIZE) {
1318 			printk(KERN_INFO
1319 			       "btrfsic: read block @logical %llu failed!\n",
1320 			       (unsigned long long)next_bytenr);
1321 			btrfsic_release_block_ctx(next_block_ctx);
1322 			*next_blockp = NULL;
1323 			return -1;
1324 		}
1325 
1326 		*next_blockp = next_block;
1327 	} else {
1328 		*next_blockp = NULL;
1329 	}
1330 	(*mirror_nump)++;
1331 
1332 	return 0;
1333 }
1334 
1335 static int btrfsic_handle_extent_data(
1336 		struct btrfsic_state *state,
1337 		struct btrfsic_block *block,
1338 		struct btrfsic_block_data_ctx *block_ctx,
1339 		u32 item_offset, int force_iodone_flag)
1340 {
1341 	int ret;
1342 	struct btrfs_file_extent_item *file_extent_item =
1343 	    (struct btrfs_file_extent_item *)(block_ctx->data +
1344 					      offsetof(struct btrfs_leaf,
1345 						       items) + item_offset);
1346 	u64 next_bytenr =
1347 	    le64_to_cpu(file_extent_item->disk_bytenr) +
1348 	    le64_to_cpu(file_extent_item->offset);
1349 	u64 num_bytes = le64_to_cpu(file_extent_item->num_bytes);
1350 	u64 generation = le64_to_cpu(file_extent_item->generation);
1351 	struct btrfsic_block_link *l;
1352 
1353 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1354 		printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1355 		       " offset = %llu, num_bytes = %llu\n",
1356 		       file_extent_item->type,
1357 		       (unsigned long long)
1358 		       le64_to_cpu(file_extent_item->disk_bytenr),
1359 		       (unsigned long long)
1360 		       le64_to_cpu(file_extent_item->offset),
1361 		       (unsigned long long)
1362 		       le64_to_cpu(file_extent_item->num_bytes));
1363 	if (BTRFS_FILE_EXTENT_REG != file_extent_item->type ||
1364 	    ((u64)0) == le64_to_cpu(file_extent_item->disk_bytenr))
1365 		return 0;
1366 	while (num_bytes > 0) {
1367 		u32 chunk_len;
1368 		int num_copies;
1369 		int mirror_num;
1370 
1371 		if (num_bytes > BTRFSIC_BLOCK_SIZE)
1372 			chunk_len = BTRFSIC_BLOCK_SIZE;
1373 		else
1374 			chunk_len = num_bytes;
1375 
1376 		num_copies =
1377 		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
1378 				     next_bytenr, PAGE_SIZE);
1379 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1380 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1381 			       (unsigned long long)next_bytenr, num_copies);
1382 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1383 			struct btrfsic_block_data_ctx next_block_ctx;
1384 			struct btrfsic_block *next_block;
1385 			int block_was_created;
1386 
1387 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1388 				printk(KERN_INFO "btrfsic_handle_extent_data("
1389 				       "mirror_num=%d)\n", mirror_num);
1390 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1391 				printk(KERN_INFO
1392 				       "\tdisk_bytenr = %llu, num_bytes %u\n",
1393 				       (unsigned long long)next_bytenr,
1394 				       chunk_len);
1395 			ret = btrfsic_map_block(state, next_bytenr,
1396 						chunk_len, &next_block_ctx,
1397 						mirror_num);
1398 			if (ret) {
1399 				printk(KERN_INFO
1400 				       "btrfsic: btrfsic_map_block(@%llu,"
1401 				       " mirror=%d) failed!\n",
1402 				       (unsigned long long)next_bytenr,
1403 				       mirror_num);
1404 				return -1;
1405 			}
1406 
1407 			next_block = btrfsic_block_lookup_or_add(
1408 					state,
1409 					&next_block_ctx,
1410 					"referenced ",
1411 					0,
1412 					force_iodone_flag,
1413 					!force_iodone_flag,
1414 					mirror_num,
1415 					&block_was_created);
1416 			if (NULL == next_block) {
1417 				printk(KERN_INFO
1418 				       "btrfsic: error, kmalloc failed!\n");
1419 				btrfsic_release_block_ctx(&next_block_ctx);
1420 				return -1;
1421 			}
1422 			if (!block_was_created) {
1423 				if (next_block->logical_bytenr != next_bytenr &&
1424 				    !(!next_block->is_metadata &&
1425 				      0 == next_block->logical_bytenr)) {
1426 					printk(KERN_INFO
1427 					       "Referenced block"
1428 					       " @%llu (%s/%llu/%d)"
1429 					       " found in hash table, D,"
1430 					       " bytenr mismatch"
1431 					       " (!= stored %llu).\n",
1432 					       (unsigned long long)next_bytenr,
1433 					       next_block_ctx.dev->name,
1434 					       (unsigned long long)
1435 					       next_block_ctx.dev_bytenr,
1436 					       mirror_num,
1437 					       (unsigned long long)
1438 					       next_block->logical_bytenr);
1439 				}
1440 				next_block->logical_bytenr = next_bytenr;
1441 				next_block->mirror_num = mirror_num;
1442 			}
1443 
1444 			l = btrfsic_block_link_lookup_or_add(state,
1445 							     &next_block_ctx,
1446 							     next_block, block,
1447 							     generation);
1448 			btrfsic_release_block_ctx(&next_block_ctx);
1449 			if (NULL == l)
1450 				return -1;
1451 		}
1452 
1453 		next_bytenr += chunk_len;
1454 		num_bytes -= chunk_len;
1455 	}
1456 
1457 	return 0;
1458 }
1459 
1460 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1461 			     struct btrfsic_block_data_ctx *block_ctx_out,
1462 			     int mirror_num)
1463 {
1464 	int ret;
1465 	u64 length;
1466 	struct btrfs_bio *multi = NULL;
1467 	struct btrfs_device *device;
1468 
1469 	length = len;
1470 	ret = btrfs_map_block(&state->root->fs_info->mapping_tree, READ,
1471 			      bytenr, &length, &multi, mirror_num);
1472 
1473 	device = multi->stripes[0].dev;
1474 	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1475 	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1476 	block_ctx_out->start = bytenr;
1477 	block_ctx_out->len = len;
1478 	block_ctx_out->data = NULL;
1479 	block_ctx_out->bh = NULL;
1480 
1481 	if (0 == ret)
1482 		kfree(multi);
1483 	if (NULL == block_ctx_out->dev) {
1484 		ret = -ENXIO;
1485 		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1486 	}
1487 
1488 	return ret;
1489 }
1490 
1491 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1492 				  u32 len, struct block_device *bdev,
1493 				  struct btrfsic_block_data_ctx *block_ctx_out)
1494 {
1495 	block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1496 	block_ctx_out->dev_bytenr = bytenr;
1497 	block_ctx_out->start = bytenr;
1498 	block_ctx_out->len = len;
1499 	block_ctx_out->data = NULL;
1500 	block_ctx_out->bh = NULL;
1501 	if (NULL != block_ctx_out->dev) {
1502 		return 0;
1503 	} else {
1504 		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1505 		return -ENXIO;
1506 	}
1507 }
1508 
1509 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1510 {
1511 	if (NULL != block_ctx->bh) {
1512 		brelse(block_ctx->bh);
1513 		block_ctx->bh = NULL;
1514 	}
1515 }
1516 
1517 static int btrfsic_read_block(struct btrfsic_state *state,
1518 			      struct btrfsic_block_data_ctx *block_ctx)
1519 {
1520 	block_ctx->bh = NULL;
1521 	if (block_ctx->dev_bytenr & 4095) {
1522 		printk(KERN_INFO
1523 		       "btrfsic: read_block() with unaligned bytenr %llu\n",
1524 		       (unsigned long long)block_ctx->dev_bytenr);
1525 		return -1;
1526 	}
1527 	if (block_ctx->len > 4096) {
1528 		printk(KERN_INFO
1529 		       "btrfsic: read_block() with too huge size %d\n",
1530 		       block_ctx->len);
1531 		return -1;
1532 	}
1533 
1534 	block_ctx->bh = __bread(block_ctx->dev->bdev,
1535 				block_ctx->dev_bytenr >> 12, 4096);
1536 	if (NULL == block_ctx->bh)
1537 		return -1;
1538 	block_ctx->data = block_ctx->bh->b_data;
1539 
1540 	return block_ctx->len;
1541 }
1542 
1543 static void btrfsic_dump_database(struct btrfsic_state *state)
1544 {
1545 	struct list_head *elem_all;
1546 
1547 	BUG_ON(NULL == state);
1548 
1549 	printk(KERN_INFO "all_blocks_list:\n");
1550 	list_for_each(elem_all, &state->all_blocks_list) {
1551 		const struct btrfsic_block *const b_all =
1552 		    list_entry(elem_all, struct btrfsic_block,
1553 			       all_blocks_node);
1554 		struct list_head *elem_ref_to;
1555 		struct list_head *elem_ref_from;
1556 
1557 		printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1558 		       btrfsic_get_block_type(state, b_all),
1559 		       (unsigned long long)b_all->logical_bytenr,
1560 		       b_all->dev_state->name,
1561 		       (unsigned long long)b_all->dev_bytenr,
1562 		       b_all->mirror_num);
1563 
1564 		list_for_each(elem_ref_to, &b_all->ref_to_list) {
1565 			const struct btrfsic_block_link *const l =
1566 			    list_entry(elem_ref_to,
1567 				       struct btrfsic_block_link,
1568 				       node_ref_to);
1569 
1570 			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1571 			       " refers %u* to"
1572 			       " %c @%llu (%s/%llu/%d)\n",
1573 			       btrfsic_get_block_type(state, b_all),
1574 			       (unsigned long long)b_all->logical_bytenr,
1575 			       b_all->dev_state->name,
1576 			       (unsigned long long)b_all->dev_bytenr,
1577 			       b_all->mirror_num,
1578 			       l->ref_cnt,
1579 			       btrfsic_get_block_type(state, l->block_ref_to),
1580 			       (unsigned long long)
1581 			       l->block_ref_to->logical_bytenr,
1582 			       l->block_ref_to->dev_state->name,
1583 			       (unsigned long long)l->block_ref_to->dev_bytenr,
1584 			       l->block_ref_to->mirror_num);
1585 		}
1586 
1587 		list_for_each(elem_ref_from, &b_all->ref_from_list) {
1588 			const struct btrfsic_block_link *const l =
1589 			    list_entry(elem_ref_from,
1590 				       struct btrfsic_block_link,
1591 				       node_ref_from);
1592 
1593 			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1594 			       " is ref %u* from"
1595 			       " %c @%llu (%s/%llu/%d)\n",
1596 			       btrfsic_get_block_type(state, b_all),
1597 			       (unsigned long long)b_all->logical_bytenr,
1598 			       b_all->dev_state->name,
1599 			       (unsigned long long)b_all->dev_bytenr,
1600 			       b_all->mirror_num,
1601 			       l->ref_cnt,
1602 			       btrfsic_get_block_type(state, l->block_ref_from),
1603 			       (unsigned long long)
1604 			       l->block_ref_from->logical_bytenr,
1605 			       l->block_ref_from->dev_state->name,
1606 			       (unsigned long long)
1607 			       l->block_ref_from->dev_bytenr,
1608 			       l->block_ref_from->mirror_num);
1609 		}
1610 
1611 		printk(KERN_INFO "\n");
1612 	}
1613 }
1614 
1615 /*
1616  * Test whether the disk block contains a tree block (leaf or node)
1617  * (note that this test fails for the super block)
1618  */
1619 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1620 				     const u8 *data, unsigned int size)
1621 {
1622 	struct btrfs_header *h;
1623 	u8 csum[BTRFS_CSUM_SIZE];
1624 	u32 crc = ~(u32)0;
1625 	int fail = 0;
1626 	int crc_fail = 0;
1627 
1628 	h = (struct btrfs_header *)data;
1629 
1630 	if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1631 		fail++;
1632 
1633 	crc = crc32c(crc, data + BTRFS_CSUM_SIZE, PAGE_SIZE - BTRFS_CSUM_SIZE);
1634 	btrfs_csum_final(crc, csum);
1635 	if (memcmp(csum, h->csum, state->csum_size))
1636 		crc_fail++;
1637 
1638 	return fail || crc_fail;
1639 }
1640 
1641 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1642 					  u64 dev_bytenr,
1643 					  u8 *mapped_data, unsigned int len,
1644 					  struct bio *bio,
1645 					  int *bio_is_patched,
1646 					  struct buffer_head *bh,
1647 					  int submit_bio_bh_rw)
1648 {
1649 	int is_metadata;
1650 	struct btrfsic_block *block;
1651 	struct btrfsic_block_data_ctx block_ctx;
1652 	int ret;
1653 	struct btrfsic_state *state = dev_state->state;
1654 	struct block_device *bdev = dev_state->bdev;
1655 
1656 	WARN_ON(len > PAGE_SIZE);
1657 	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_data, len));
1658 	if (NULL != bio_is_patched)
1659 		*bio_is_patched = 0;
1660 
1661 	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1662 					       &state->block_hashtable);
1663 	if (NULL != block) {
1664 		u64 bytenr = 0;
1665 		struct list_head *elem_ref_to;
1666 		struct list_head *tmp_ref_to;
1667 
1668 		if (block->is_superblock) {
1669 			bytenr = le64_to_cpu(((struct btrfs_super_block *)
1670 					      mapped_data)->bytenr);
1671 			is_metadata = 1;
1672 			if (state->print_mask &
1673 			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1674 				printk(KERN_INFO
1675 				       "[before new superblock is written]:\n");
1676 				btrfsic_dump_tree_sub(state, block, 0);
1677 			}
1678 		}
1679 		if (is_metadata) {
1680 			if (!block->is_superblock) {
1681 				bytenr = le64_to_cpu(((struct btrfs_header *)
1682 						      mapped_data)->bytenr);
1683 				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1684 							       dev_state,
1685 							       dev_bytenr,
1686 							       mapped_data);
1687 			}
1688 			if (block->logical_bytenr != bytenr) {
1689 				printk(KERN_INFO
1690 				       "Written block @%llu (%s/%llu/%d)"
1691 				       " found in hash table, %c,"
1692 				       " bytenr mismatch"
1693 				       " (!= stored %llu).\n",
1694 				       (unsigned long long)bytenr,
1695 				       dev_state->name,
1696 				       (unsigned long long)dev_bytenr,
1697 				       block->mirror_num,
1698 				       btrfsic_get_block_type(state, block),
1699 				       (unsigned long long)
1700 				       block->logical_bytenr);
1701 				block->logical_bytenr = bytenr;
1702 			} else if (state->print_mask &
1703 				   BTRFSIC_PRINT_MASK_VERBOSE)
1704 				printk(KERN_INFO
1705 				       "Written block @%llu (%s/%llu/%d)"
1706 				       " found in hash table, %c.\n",
1707 				       (unsigned long long)bytenr,
1708 				       dev_state->name,
1709 				       (unsigned long long)dev_bytenr,
1710 				       block->mirror_num,
1711 				       btrfsic_get_block_type(state, block));
1712 		} else {
1713 			bytenr = block->logical_bytenr;
1714 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1715 				printk(KERN_INFO
1716 				       "Written block @%llu (%s/%llu/%d)"
1717 				       " found in hash table, %c.\n",
1718 				       (unsigned long long)bytenr,
1719 				       dev_state->name,
1720 				       (unsigned long long)dev_bytenr,
1721 				       block->mirror_num,
1722 				       btrfsic_get_block_type(state, block));
1723 		}
1724 
1725 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1726 			printk(KERN_INFO
1727 			       "ref_to_list: %cE, ref_from_list: %cE\n",
1728 			       list_empty(&block->ref_to_list) ? ' ' : '!',
1729 			       list_empty(&block->ref_from_list) ? ' ' : '!');
1730 		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1731 			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1732 			       " @%llu (%s/%llu/%d), old(gen=%llu,"
1733 			       " objectid=%llu, type=%d, offset=%llu),"
1734 			       " new(gen=%llu),"
1735 			       " which is referenced by most recent superblock"
1736 			       " (superblockgen=%llu)!\n",
1737 			       btrfsic_get_block_type(state, block),
1738 			       (unsigned long long)bytenr,
1739 			       dev_state->name,
1740 			       (unsigned long long)dev_bytenr,
1741 			       block->mirror_num,
1742 			       (unsigned long long)block->generation,
1743 			       (unsigned long long)
1744 			       le64_to_cpu(block->disk_key.objectid),
1745 			       block->disk_key.type,
1746 			       (unsigned long long)
1747 			       le64_to_cpu(block->disk_key.offset),
1748 			       (unsigned long long)
1749 			       le64_to_cpu(((struct btrfs_header *)
1750 					    mapped_data)->generation),
1751 			       (unsigned long long)
1752 			       state->max_superblock_generation);
1753 			btrfsic_dump_tree(state);
1754 		}
1755 
1756 		if (!block->is_iodone && !block->never_written) {
1757 			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1758 			       " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
1759 			       " which is not yet iodone!\n",
1760 			       btrfsic_get_block_type(state, block),
1761 			       (unsigned long long)bytenr,
1762 			       dev_state->name,
1763 			       (unsigned long long)dev_bytenr,
1764 			       block->mirror_num,
1765 			       (unsigned long long)block->generation,
1766 			       (unsigned long long)
1767 			       le64_to_cpu(((struct btrfs_header *)
1768 					    mapped_data)->generation));
1769 			/* it would not be safe to go on */
1770 			btrfsic_dump_tree(state);
1771 			return;
1772 		}
1773 
1774 		/*
1775 		 * Clear all references of this block. Do not free
1776 		 * the block itself even if is not referenced anymore
1777 		 * because it still carries valueable information
1778 		 * like whether it was ever written and IO completed.
1779 		 */
1780 		list_for_each_safe(elem_ref_to, tmp_ref_to,
1781 				   &block->ref_to_list) {
1782 			struct btrfsic_block_link *const l =
1783 			    list_entry(elem_ref_to,
1784 				       struct btrfsic_block_link,
1785 				       node_ref_to);
1786 
1787 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1788 				btrfsic_print_rem_link(state, l);
1789 			l->ref_cnt--;
1790 			if (0 == l->ref_cnt) {
1791 				list_del(&l->node_ref_to);
1792 				list_del(&l->node_ref_from);
1793 				btrfsic_block_link_hashtable_remove(l);
1794 				btrfsic_block_link_free(l);
1795 			}
1796 		}
1797 
1798 		if (block->is_superblock)
1799 			ret = btrfsic_map_superblock(state, bytenr, len,
1800 						     bdev, &block_ctx);
1801 		else
1802 			ret = btrfsic_map_block(state, bytenr, len,
1803 						&block_ctx, 0);
1804 		if (ret) {
1805 			printk(KERN_INFO
1806 			       "btrfsic: btrfsic_map_block(root @%llu)"
1807 			       " failed!\n", (unsigned long long)bytenr);
1808 			return;
1809 		}
1810 		block_ctx.data = mapped_data;
1811 		/* the following is required in case of writes to mirrors,
1812 		 * use the same that was used for the lookup */
1813 		block_ctx.dev = dev_state;
1814 		block_ctx.dev_bytenr = dev_bytenr;
1815 
1816 		if (is_metadata || state->include_extent_data) {
1817 			block->never_written = 0;
1818 			block->iodone_w_error = 0;
1819 			if (NULL != bio) {
1820 				block->is_iodone = 0;
1821 				BUG_ON(NULL == bio_is_patched);
1822 				if (!*bio_is_patched) {
1823 					block->orig_bio_bh_private =
1824 					    bio->bi_private;
1825 					block->orig_bio_bh_end_io.bio =
1826 					    bio->bi_end_io;
1827 					block->next_in_same_bio = NULL;
1828 					bio->bi_private = block;
1829 					bio->bi_end_io = btrfsic_bio_end_io;
1830 					*bio_is_patched = 1;
1831 				} else {
1832 					struct btrfsic_block *chained_block =
1833 					    (struct btrfsic_block *)
1834 					    bio->bi_private;
1835 
1836 					BUG_ON(NULL == chained_block);
1837 					block->orig_bio_bh_private =
1838 					    chained_block->orig_bio_bh_private;
1839 					block->orig_bio_bh_end_io.bio =
1840 					    chained_block->orig_bio_bh_end_io.
1841 					    bio;
1842 					block->next_in_same_bio = chained_block;
1843 					bio->bi_private = block;
1844 				}
1845 			} else if (NULL != bh) {
1846 				block->is_iodone = 0;
1847 				block->orig_bio_bh_private = bh->b_private;
1848 				block->orig_bio_bh_end_io.bh = bh->b_end_io;
1849 				block->next_in_same_bio = NULL;
1850 				bh->b_private = block;
1851 				bh->b_end_io = btrfsic_bh_end_io;
1852 			} else {
1853 				block->is_iodone = 1;
1854 				block->orig_bio_bh_private = NULL;
1855 				block->orig_bio_bh_end_io.bio = NULL;
1856 				block->next_in_same_bio = NULL;
1857 			}
1858 		}
1859 
1860 		block->flush_gen = dev_state->last_flush_gen + 1;
1861 		block->submit_bio_bh_rw = submit_bio_bh_rw;
1862 		if (is_metadata) {
1863 			block->logical_bytenr = bytenr;
1864 			block->is_metadata = 1;
1865 			if (block->is_superblock) {
1866 				ret = btrfsic_process_written_superblock(
1867 						state,
1868 						block,
1869 						(struct btrfs_super_block *)
1870 						mapped_data);
1871 				if (state->print_mask &
1872 				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
1873 					printk(KERN_INFO
1874 					"[after new superblock is written]:\n");
1875 					btrfsic_dump_tree_sub(state, block, 0);
1876 				}
1877 			} else {
1878 				block->mirror_num = 0;	/* unknown */
1879 				ret = btrfsic_process_metablock(
1880 						state,
1881 						block,
1882 						&block_ctx,
1883 						(struct btrfs_header *)
1884 						block_ctx.data,
1885 						0, 0);
1886 			}
1887 			if (ret)
1888 				printk(KERN_INFO
1889 				       "btrfsic: btrfsic_process_metablock"
1890 				       "(root @%llu) failed!\n",
1891 				       (unsigned long long)dev_bytenr);
1892 		} else {
1893 			block->is_metadata = 0;
1894 			block->mirror_num = 0;	/* unknown */
1895 			block->generation = BTRFSIC_GENERATION_UNKNOWN;
1896 			if (!state->include_extent_data
1897 			    && list_empty(&block->ref_from_list)) {
1898 				/*
1899 				 * disk block is overwritten with extent
1900 				 * data (not meta data) and we are configured
1901 				 * to not include extent data: take the
1902 				 * chance and free the block's memory
1903 				 */
1904 				btrfsic_block_hashtable_remove(block);
1905 				list_del(&block->all_blocks_node);
1906 				btrfsic_block_free(block);
1907 			}
1908 		}
1909 		btrfsic_release_block_ctx(&block_ctx);
1910 	} else {
1911 		/* block has not been found in hash table */
1912 		u64 bytenr;
1913 
1914 		if (!is_metadata) {
1915 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1916 				printk(KERN_INFO "Written block (%s/%llu/?)"
1917 				       " !found in hash table, D.\n",
1918 				       dev_state->name,
1919 				       (unsigned long long)dev_bytenr);
1920 			if (!state->include_extent_data)
1921 				return;	/* ignore that written D block */
1922 
1923 			/* this is getting ugly for the
1924 			 * include_extent_data case... */
1925 			bytenr = 0;	/* unknown */
1926 			block_ctx.start = bytenr;
1927 			block_ctx.len = len;
1928 			block_ctx.bh = NULL;
1929 		} else {
1930 			bytenr = le64_to_cpu(((struct btrfs_header *)
1931 					      mapped_data)->bytenr);
1932 			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
1933 						       dev_bytenr,
1934 						       mapped_data);
1935 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1936 				printk(KERN_INFO
1937 				       "Written block @%llu (%s/%llu/?)"
1938 				       " !found in hash table, M.\n",
1939 				       (unsigned long long)bytenr,
1940 				       dev_state->name,
1941 				       (unsigned long long)dev_bytenr);
1942 
1943 			ret = btrfsic_map_block(state, bytenr, len, &block_ctx,
1944 						0);
1945 			if (ret) {
1946 				printk(KERN_INFO
1947 				       "btrfsic: btrfsic_map_block(root @%llu)"
1948 				       " failed!\n",
1949 				       (unsigned long long)dev_bytenr);
1950 				return;
1951 			}
1952 		}
1953 		block_ctx.data = mapped_data;
1954 		/* the following is required in case of writes to mirrors,
1955 		 * use the same that was used for the lookup */
1956 		block_ctx.dev = dev_state;
1957 		block_ctx.dev_bytenr = dev_bytenr;
1958 
1959 		block = btrfsic_block_alloc();
1960 		if (NULL == block) {
1961 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1962 			btrfsic_release_block_ctx(&block_ctx);
1963 			return;
1964 		}
1965 		block->dev_state = dev_state;
1966 		block->dev_bytenr = dev_bytenr;
1967 		block->logical_bytenr = bytenr;
1968 		block->is_metadata = is_metadata;
1969 		block->never_written = 0;
1970 		block->iodone_w_error = 0;
1971 		block->mirror_num = 0;	/* unknown */
1972 		block->flush_gen = dev_state->last_flush_gen + 1;
1973 		block->submit_bio_bh_rw = submit_bio_bh_rw;
1974 		if (NULL != bio) {
1975 			block->is_iodone = 0;
1976 			BUG_ON(NULL == bio_is_patched);
1977 			if (!*bio_is_patched) {
1978 				block->orig_bio_bh_private = bio->bi_private;
1979 				block->orig_bio_bh_end_io.bio = bio->bi_end_io;
1980 				block->next_in_same_bio = NULL;
1981 				bio->bi_private = block;
1982 				bio->bi_end_io = btrfsic_bio_end_io;
1983 				*bio_is_patched = 1;
1984 			} else {
1985 				struct btrfsic_block *chained_block =
1986 				    (struct btrfsic_block *)
1987 				    bio->bi_private;
1988 
1989 				BUG_ON(NULL == chained_block);
1990 				block->orig_bio_bh_private =
1991 				    chained_block->orig_bio_bh_private;
1992 				block->orig_bio_bh_end_io.bio =
1993 				    chained_block->orig_bio_bh_end_io.bio;
1994 				block->next_in_same_bio = chained_block;
1995 				bio->bi_private = block;
1996 			}
1997 		} else if (NULL != bh) {
1998 			block->is_iodone = 0;
1999 			block->orig_bio_bh_private = bh->b_private;
2000 			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2001 			block->next_in_same_bio = NULL;
2002 			bh->b_private = block;
2003 			bh->b_end_io = btrfsic_bh_end_io;
2004 		} else {
2005 			block->is_iodone = 1;
2006 			block->orig_bio_bh_private = NULL;
2007 			block->orig_bio_bh_end_io.bio = NULL;
2008 			block->next_in_same_bio = NULL;
2009 		}
2010 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2011 			printk(KERN_INFO
2012 			       "New written %c-block @%llu (%s/%llu/%d)\n",
2013 			       is_metadata ? 'M' : 'D',
2014 			       (unsigned long long)block->logical_bytenr,
2015 			       block->dev_state->name,
2016 			       (unsigned long long)block->dev_bytenr,
2017 			       block->mirror_num);
2018 		list_add(&block->all_blocks_node, &state->all_blocks_list);
2019 		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2020 
2021 		if (is_metadata) {
2022 			ret = btrfsic_process_metablock(state, block,
2023 							&block_ctx,
2024 							(struct btrfs_header *)
2025 							block_ctx.data, 0, 0);
2026 			if (ret)
2027 				printk(KERN_INFO
2028 				       "btrfsic: process_metablock(root @%llu)"
2029 				       " failed!\n",
2030 				       (unsigned long long)dev_bytenr);
2031 		}
2032 		btrfsic_release_block_ctx(&block_ctx);
2033 	}
2034 }
2035 
2036 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2037 {
2038 	struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2039 	int iodone_w_error;
2040 
2041 	/* mutex is not held! This is not save if IO is not yet completed
2042 	 * on umount */
2043 	iodone_w_error = 0;
2044 	if (bio_error_status)
2045 		iodone_w_error = 1;
2046 
2047 	BUG_ON(NULL == block);
2048 	bp->bi_private = block->orig_bio_bh_private;
2049 	bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2050 
2051 	do {
2052 		struct btrfsic_block *next_block;
2053 		struct btrfsic_dev_state *const dev_state = block->dev_state;
2054 
2055 		if ((dev_state->state->print_mask &
2056 		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2057 			printk(KERN_INFO
2058 			       "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2059 			       bio_error_status,
2060 			       btrfsic_get_block_type(dev_state->state, block),
2061 			       (unsigned long long)block->logical_bytenr,
2062 			       dev_state->name,
2063 			       (unsigned long long)block->dev_bytenr,
2064 			       block->mirror_num);
2065 		next_block = block->next_in_same_bio;
2066 		block->iodone_w_error = iodone_w_error;
2067 		if (block->submit_bio_bh_rw & REQ_FLUSH) {
2068 			dev_state->last_flush_gen++;
2069 			if ((dev_state->state->print_mask &
2070 			     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2071 				printk(KERN_INFO
2072 				       "bio_end_io() new %s flush_gen=%llu\n",
2073 				       dev_state->name,
2074 				       (unsigned long long)
2075 				       dev_state->last_flush_gen);
2076 		}
2077 		if (block->submit_bio_bh_rw & REQ_FUA)
2078 			block->flush_gen = 0; /* FUA completed means block is
2079 					       * on disk */
2080 		block->is_iodone = 1; /* for FLUSH, this releases the block */
2081 		block = next_block;
2082 	} while (NULL != block);
2083 
2084 	bp->bi_end_io(bp, bio_error_status);
2085 }
2086 
2087 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2088 {
2089 	struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2090 	int iodone_w_error = !uptodate;
2091 	struct btrfsic_dev_state *dev_state;
2092 
2093 	BUG_ON(NULL == block);
2094 	dev_state = block->dev_state;
2095 	if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2096 		printk(KERN_INFO
2097 		       "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2098 		       iodone_w_error,
2099 		       btrfsic_get_block_type(dev_state->state, block),
2100 		       (unsigned long long)block->logical_bytenr,
2101 		       block->dev_state->name,
2102 		       (unsigned long long)block->dev_bytenr,
2103 		       block->mirror_num);
2104 
2105 	block->iodone_w_error = iodone_w_error;
2106 	if (block->submit_bio_bh_rw & REQ_FLUSH) {
2107 		dev_state->last_flush_gen++;
2108 		if ((dev_state->state->print_mask &
2109 		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2110 			printk(KERN_INFO
2111 			       "bh_end_io() new %s flush_gen=%llu\n",
2112 			       dev_state->name,
2113 			       (unsigned long long)dev_state->last_flush_gen);
2114 	}
2115 	if (block->submit_bio_bh_rw & REQ_FUA)
2116 		block->flush_gen = 0; /* FUA completed means block is on disk */
2117 
2118 	bh->b_private = block->orig_bio_bh_private;
2119 	bh->b_end_io = block->orig_bio_bh_end_io.bh;
2120 	block->is_iodone = 1; /* for FLUSH, this releases the block */
2121 	bh->b_end_io(bh, uptodate);
2122 }
2123 
2124 static int btrfsic_process_written_superblock(
2125 		struct btrfsic_state *state,
2126 		struct btrfsic_block *const superblock,
2127 		struct btrfs_super_block *const super_hdr)
2128 {
2129 	int pass;
2130 
2131 	superblock->generation = btrfs_super_generation(super_hdr);
2132 	if (!(superblock->generation > state->max_superblock_generation ||
2133 	      0 == state->max_superblock_generation)) {
2134 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2135 			printk(KERN_INFO
2136 			       "btrfsic: superblock @%llu (%s/%llu/%d)"
2137 			       " with old gen %llu <= %llu\n",
2138 			       (unsigned long long)superblock->logical_bytenr,
2139 			       superblock->dev_state->name,
2140 			       (unsigned long long)superblock->dev_bytenr,
2141 			       superblock->mirror_num,
2142 			       (unsigned long long)
2143 			       btrfs_super_generation(super_hdr),
2144 			       (unsigned long long)
2145 			       state->max_superblock_generation);
2146 	} else {
2147 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2148 			printk(KERN_INFO
2149 			       "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2150 			       " with new gen %llu > %llu\n",
2151 			       (unsigned long long)superblock->logical_bytenr,
2152 			       superblock->dev_state->name,
2153 			       (unsigned long long)superblock->dev_bytenr,
2154 			       superblock->mirror_num,
2155 			       (unsigned long long)
2156 			       btrfs_super_generation(super_hdr),
2157 			       (unsigned long long)
2158 			       state->max_superblock_generation);
2159 
2160 		state->max_superblock_generation =
2161 		    btrfs_super_generation(super_hdr);
2162 		state->latest_superblock = superblock;
2163 	}
2164 
2165 	for (pass = 0; pass < 3; pass++) {
2166 		int ret;
2167 		u64 next_bytenr;
2168 		struct btrfsic_block *next_block;
2169 		struct btrfsic_block_data_ctx tmp_next_block_ctx;
2170 		struct btrfsic_block_link *l;
2171 		int num_copies;
2172 		int mirror_num;
2173 		const char *additional_string = NULL;
2174 		struct btrfs_disk_key tmp_disk_key;
2175 
2176 		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
2177 		tmp_disk_key.offset = 0;
2178 
2179 		switch (pass) {
2180 		case 0:
2181 			tmp_disk_key.objectid =
2182 			    cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
2183 			additional_string = "root ";
2184 			next_bytenr = btrfs_super_root(super_hdr);
2185 			if (state->print_mask &
2186 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2187 				printk(KERN_INFO "root@%llu\n",
2188 				       (unsigned long long)next_bytenr);
2189 			break;
2190 		case 1:
2191 			tmp_disk_key.objectid =
2192 			    cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
2193 			additional_string = "chunk ";
2194 			next_bytenr = btrfs_super_chunk_root(super_hdr);
2195 			if (state->print_mask &
2196 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2197 				printk(KERN_INFO "chunk@%llu\n",
2198 				       (unsigned long long)next_bytenr);
2199 			break;
2200 		case 2:
2201 			tmp_disk_key.objectid =
2202 			    cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
2203 			additional_string = "log ";
2204 			next_bytenr = btrfs_super_log_root(super_hdr);
2205 			if (0 == next_bytenr)
2206 				continue;
2207 			if (state->print_mask &
2208 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2209 				printk(KERN_INFO "log@%llu\n",
2210 				       (unsigned long long)next_bytenr);
2211 			break;
2212 		}
2213 
2214 		num_copies =
2215 		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
2216 				     next_bytenr, PAGE_SIZE);
2217 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2218 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2219 			       (unsigned long long)next_bytenr, num_copies);
2220 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2221 			int was_created;
2222 
2223 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2224 				printk(KERN_INFO
2225 				       "btrfsic_process_written_superblock("
2226 				       "mirror_num=%d)\n", mirror_num);
2227 			ret = btrfsic_map_block(state, next_bytenr, PAGE_SIZE,
2228 						&tmp_next_block_ctx,
2229 						mirror_num);
2230 			if (ret) {
2231 				printk(KERN_INFO
2232 				       "btrfsic: btrfsic_map_block(@%llu,"
2233 				       " mirror=%d) failed!\n",
2234 				       (unsigned long long)next_bytenr,
2235 				       mirror_num);
2236 				return -1;
2237 			}
2238 
2239 			next_block = btrfsic_block_lookup_or_add(
2240 					state,
2241 					&tmp_next_block_ctx,
2242 					additional_string,
2243 					1, 0, 1,
2244 					mirror_num,
2245 					&was_created);
2246 			if (NULL == next_block) {
2247 				printk(KERN_INFO
2248 				       "btrfsic: error, kmalloc failed!\n");
2249 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
2250 				return -1;
2251 			}
2252 
2253 			next_block->disk_key = tmp_disk_key;
2254 			if (was_created)
2255 				next_block->generation =
2256 				    BTRFSIC_GENERATION_UNKNOWN;
2257 			l = btrfsic_block_link_lookup_or_add(
2258 					state,
2259 					&tmp_next_block_ctx,
2260 					next_block,
2261 					superblock,
2262 					BTRFSIC_GENERATION_UNKNOWN);
2263 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
2264 			if (NULL == l)
2265 				return -1;
2266 		}
2267 	}
2268 
2269 	if (-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)) {
2270 		WARN_ON(1);
2271 		btrfsic_dump_tree(state);
2272 	}
2273 
2274 	return 0;
2275 }
2276 
2277 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2278 					struct btrfsic_block *const block,
2279 					int recursion_level)
2280 {
2281 	struct list_head *elem_ref_to;
2282 	int ret = 0;
2283 
2284 	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2285 		/*
2286 		 * Note that this situation can happen and does not
2287 		 * indicate an error in regular cases. It happens
2288 		 * when disk blocks are freed and later reused.
2289 		 * The check-integrity module is not aware of any
2290 		 * block free operations, it just recognizes block
2291 		 * write operations. Therefore it keeps the linkage
2292 		 * information for a block until a block is
2293 		 * rewritten. This can temporarily cause incorrect
2294 		 * and even circular linkage informations. This
2295 		 * causes no harm unless such blocks are referenced
2296 		 * by the most recent super block.
2297 		 */
2298 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2299 			printk(KERN_INFO
2300 			       "btrfsic: abort cyclic linkage (case 1).\n");
2301 
2302 		return ret;
2303 	}
2304 
2305 	/*
2306 	 * This algorithm is recursive because the amount of used stack
2307 	 * space is very small and the max recursion depth is limited.
2308 	 */
2309 	list_for_each(elem_ref_to, &block->ref_to_list) {
2310 		const struct btrfsic_block_link *const l =
2311 		    list_entry(elem_ref_to, struct btrfsic_block_link,
2312 			       node_ref_to);
2313 
2314 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2315 			printk(KERN_INFO
2316 			       "rl=%d, %c @%llu (%s/%llu/%d)"
2317 			       " %u* refers to %c @%llu (%s/%llu/%d)\n",
2318 			       recursion_level,
2319 			       btrfsic_get_block_type(state, block),
2320 			       (unsigned long long)block->logical_bytenr,
2321 			       block->dev_state->name,
2322 			       (unsigned long long)block->dev_bytenr,
2323 			       block->mirror_num,
2324 			       l->ref_cnt,
2325 			       btrfsic_get_block_type(state, l->block_ref_to),
2326 			       (unsigned long long)
2327 			       l->block_ref_to->logical_bytenr,
2328 			       l->block_ref_to->dev_state->name,
2329 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2330 			       l->block_ref_to->mirror_num);
2331 		if (l->block_ref_to->never_written) {
2332 			printk(KERN_INFO "btrfs: attempt to write superblock"
2333 			       " which references block %c @%llu (%s/%llu/%d)"
2334 			       " which is never written!\n",
2335 			       btrfsic_get_block_type(state, l->block_ref_to),
2336 			       (unsigned long long)
2337 			       l->block_ref_to->logical_bytenr,
2338 			       l->block_ref_to->dev_state->name,
2339 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2340 			       l->block_ref_to->mirror_num);
2341 			ret = -1;
2342 		} else if (!l->block_ref_to->is_iodone) {
2343 			printk(KERN_INFO "btrfs: attempt to write superblock"
2344 			       " which references block %c @%llu (%s/%llu/%d)"
2345 			       " which is not yet iodone!\n",
2346 			       btrfsic_get_block_type(state, l->block_ref_to),
2347 			       (unsigned long long)
2348 			       l->block_ref_to->logical_bytenr,
2349 			       l->block_ref_to->dev_state->name,
2350 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2351 			       l->block_ref_to->mirror_num);
2352 			ret = -1;
2353 		} else if (l->parent_generation !=
2354 			   l->block_ref_to->generation &&
2355 			   BTRFSIC_GENERATION_UNKNOWN !=
2356 			   l->parent_generation &&
2357 			   BTRFSIC_GENERATION_UNKNOWN !=
2358 			   l->block_ref_to->generation) {
2359 			printk(KERN_INFO "btrfs: attempt to write superblock"
2360 			       " which references block %c @%llu (%s/%llu/%d)"
2361 			       " with generation %llu !="
2362 			       " parent generation %llu!\n",
2363 			       btrfsic_get_block_type(state, l->block_ref_to),
2364 			       (unsigned long long)
2365 			       l->block_ref_to->logical_bytenr,
2366 			       l->block_ref_to->dev_state->name,
2367 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2368 			       l->block_ref_to->mirror_num,
2369 			       (unsigned long long)l->block_ref_to->generation,
2370 			       (unsigned long long)l->parent_generation);
2371 			ret = -1;
2372 		} else if (l->block_ref_to->flush_gen >
2373 			   l->block_ref_to->dev_state->last_flush_gen) {
2374 			printk(KERN_INFO "btrfs: attempt to write superblock"
2375 			       " which references block %c @%llu (%s/%llu/%d)"
2376 			       " which is not flushed out of disk's write cache"
2377 			       " (block flush_gen=%llu,"
2378 			       " dev->flush_gen=%llu)!\n",
2379 			       btrfsic_get_block_type(state, l->block_ref_to),
2380 			       (unsigned long long)
2381 			       l->block_ref_to->logical_bytenr,
2382 			       l->block_ref_to->dev_state->name,
2383 			       (unsigned long long)l->block_ref_to->dev_bytenr,
2384 			       l->block_ref_to->mirror_num,
2385 			       (unsigned long long)block->flush_gen,
2386 			       (unsigned long long)
2387 			       l->block_ref_to->dev_state->last_flush_gen);
2388 			ret = -1;
2389 		} else if (-1 == btrfsic_check_all_ref_blocks(state,
2390 							      l->block_ref_to,
2391 							      recursion_level +
2392 							      1)) {
2393 			ret = -1;
2394 		}
2395 	}
2396 
2397 	return ret;
2398 }
2399 
2400 static int btrfsic_is_block_ref_by_superblock(
2401 		const struct btrfsic_state *state,
2402 		const struct btrfsic_block *block,
2403 		int recursion_level)
2404 {
2405 	struct list_head *elem_ref_from;
2406 
2407 	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2408 		/* refer to comment at "abort cyclic linkage (case 1)" */
2409 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2410 			printk(KERN_INFO
2411 			       "btrfsic: abort cyclic linkage (case 2).\n");
2412 
2413 		return 0;
2414 	}
2415 
2416 	/*
2417 	 * This algorithm is recursive because the amount of used stack space
2418 	 * is very small and the max recursion depth is limited.
2419 	 */
2420 	list_for_each(elem_ref_from, &block->ref_from_list) {
2421 		const struct btrfsic_block_link *const l =
2422 		    list_entry(elem_ref_from, struct btrfsic_block_link,
2423 			       node_ref_from);
2424 
2425 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2426 			printk(KERN_INFO
2427 			       "rl=%d, %c @%llu (%s/%llu/%d)"
2428 			       " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2429 			       recursion_level,
2430 			       btrfsic_get_block_type(state, block),
2431 			       (unsigned long long)block->logical_bytenr,
2432 			       block->dev_state->name,
2433 			       (unsigned long long)block->dev_bytenr,
2434 			       block->mirror_num,
2435 			       l->ref_cnt,
2436 			       btrfsic_get_block_type(state, l->block_ref_from),
2437 			       (unsigned long long)
2438 			       l->block_ref_from->logical_bytenr,
2439 			       l->block_ref_from->dev_state->name,
2440 			       (unsigned long long)
2441 			       l->block_ref_from->dev_bytenr,
2442 			       l->block_ref_from->mirror_num);
2443 		if (l->block_ref_from->is_superblock &&
2444 		    state->latest_superblock->dev_bytenr ==
2445 		    l->block_ref_from->dev_bytenr &&
2446 		    state->latest_superblock->dev_state->bdev ==
2447 		    l->block_ref_from->dev_state->bdev)
2448 			return 1;
2449 		else if (btrfsic_is_block_ref_by_superblock(state,
2450 							    l->block_ref_from,
2451 							    recursion_level +
2452 							    1))
2453 			return 1;
2454 	}
2455 
2456 	return 0;
2457 }
2458 
2459 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2460 				   const struct btrfsic_block_link *l)
2461 {
2462 	printk(KERN_INFO
2463 	       "Add %u* link from %c @%llu (%s/%llu/%d)"
2464 	       " to %c @%llu (%s/%llu/%d).\n",
2465 	       l->ref_cnt,
2466 	       btrfsic_get_block_type(state, l->block_ref_from),
2467 	       (unsigned long long)l->block_ref_from->logical_bytenr,
2468 	       l->block_ref_from->dev_state->name,
2469 	       (unsigned long long)l->block_ref_from->dev_bytenr,
2470 	       l->block_ref_from->mirror_num,
2471 	       btrfsic_get_block_type(state, l->block_ref_to),
2472 	       (unsigned long long)l->block_ref_to->logical_bytenr,
2473 	       l->block_ref_to->dev_state->name,
2474 	       (unsigned long long)l->block_ref_to->dev_bytenr,
2475 	       l->block_ref_to->mirror_num);
2476 }
2477 
2478 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2479 				   const struct btrfsic_block_link *l)
2480 {
2481 	printk(KERN_INFO
2482 	       "Rem %u* link from %c @%llu (%s/%llu/%d)"
2483 	       " to %c @%llu (%s/%llu/%d).\n",
2484 	       l->ref_cnt,
2485 	       btrfsic_get_block_type(state, l->block_ref_from),
2486 	       (unsigned long long)l->block_ref_from->logical_bytenr,
2487 	       l->block_ref_from->dev_state->name,
2488 	       (unsigned long long)l->block_ref_from->dev_bytenr,
2489 	       l->block_ref_from->mirror_num,
2490 	       btrfsic_get_block_type(state, l->block_ref_to),
2491 	       (unsigned long long)l->block_ref_to->logical_bytenr,
2492 	       l->block_ref_to->dev_state->name,
2493 	       (unsigned long long)l->block_ref_to->dev_bytenr,
2494 	       l->block_ref_to->mirror_num);
2495 }
2496 
2497 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2498 				   const struct btrfsic_block *block)
2499 {
2500 	if (block->is_superblock &&
2501 	    state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2502 	    state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2503 		return 'S';
2504 	else if (block->is_superblock)
2505 		return 's';
2506 	else if (block->is_metadata)
2507 		return 'M';
2508 	else
2509 		return 'D';
2510 }
2511 
2512 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2513 {
2514 	btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2515 }
2516 
2517 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2518 				  const struct btrfsic_block *block,
2519 				  int indent_level)
2520 {
2521 	struct list_head *elem_ref_to;
2522 	int indent_add;
2523 	static char buf[80];
2524 	int cursor_position;
2525 
2526 	/*
2527 	 * Should better fill an on-stack buffer with a complete line and
2528 	 * dump it at once when it is time to print a newline character.
2529 	 */
2530 
2531 	/*
2532 	 * This algorithm is recursive because the amount of used stack space
2533 	 * is very small and the max recursion depth is limited.
2534 	 */
2535 	indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2536 			     btrfsic_get_block_type(state, block),
2537 			     (unsigned long long)block->logical_bytenr,
2538 			     block->dev_state->name,
2539 			     (unsigned long long)block->dev_bytenr,
2540 			     block->mirror_num);
2541 	if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2542 		printk("[...]\n");
2543 		return;
2544 	}
2545 	printk(buf);
2546 	indent_level += indent_add;
2547 	if (list_empty(&block->ref_to_list)) {
2548 		printk("\n");
2549 		return;
2550 	}
2551 	if (block->mirror_num > 1 &&
2552 	    !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2553 		printk(" [...]\n");
2554 		return;
2555 	}
2556 
2557 	cursor_position = indent_level;
2558 	list_for_each(elem_ref_to, &block->ref_to_list) {
2559 		const struct btrfsic_block_link *const l =
2560 		    list_entry(elem_ref_to, struct btrfsic_block_link,
2561 			       node_ref_to);
2562 
2563 		while (cursor_position < indent_level) {
2564 			printk(" ");
2565 			cursor_position++;
2566 		}
2567 		if (l->ref_cnt > 1)
2568 			indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2569 		else
2570 			indent_add = sprintf(buf, " --> ");
2571 		if (indent_level + indent_add >
2572 		    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2573 			printk("[...]\n");
2574 			cursor_position = 0;
2575 			continue;
2576 		}
2577 
2578 		printk(buf);
2579 
2580 		btrfsic_dump_tree_sub(state, l->block_ref_to,
2581 				      indent_level + indent_add);
2582 		cursor_position = 0;
2583 	}
2584 }
2585 
2586 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2587 		struct btrfsic_state *state,
2588 		struct btrfsic_block_data_ctx *next_block_ctx,
2589 		struct btrfsic_block *next_block,
2590 		struct btrfsic_block *from_block,
2591 		u64 parent_generation)
2592 {
2593 	struct btrfsic_block_link *l;
2594 
2595 	l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2596 						next_block_ctx->dev_bytenr,
2597 						from_block->dev_state->bdev,
2598 						from_block->dev_bytenr,
2599 						&state->block_link_hashtable);
2600 	if (NULL == l) {
2601 		l = btrfsic_block_link_alloc();
2602 		if (NULL == l) {
2603 			printk(KERN_INFO
2604 			       "btrfsic: error, kmalloc" " failed!\n");
2605 			return NULL;
2606 		}
2607 
2608 		l->block_ref_to = next_block;
2609 		l->block_ref_from = from_block;
2610 		l->ref_cnt = 1;
2611 		l->parent_generation = parent_generation;
2612 
2613 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2614 			btrfsic_print_add_link(state, l);
2615 
2616 		list_add(&l->node_ref_to, &from_block->ref_to_list);
2617 		list_add(&l->node_ref_from, &next_block->ref_from_list);
2618 
2619 		btrfsic_block_link_hashtable_add(l,
2620 						 &state->block_link_hashtable);
2621 	} else {
2622 		l->ref_cnt++;
2623 		l->parent_generation = parent_generation;
2624 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2625 			btrfsic_print_add_link(state, l);
2626 	}
2627 
2628 	return l;
2629 }
2630 
2631 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2632 		struct btrfsic_state *state,
2633 		struct btrfsic_block_data_ctx *block_ctx,
2634 		const char *additional_string,
2635 		int is_metadata,
2636 		int is_iodone,
2637 		int never_written,
2638 		int mirror_num,
2639 		int *was_created)
2640 {
2641 	struct btrfsic_block *block;
2642 
2643 	block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2644 					       block_ctx->dev_bytenr,
2645 					       &state->block_hashtable);
2646 	if (NULL == block) {
2647 		struct btrfsic_dev_state *dev_state;
2648 
2649 		block = btrfsic_block_alloc();
2650 		if (NULL == block) {
2651 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2652 			return NULL;
2653 		}
2654 		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2655 		if (NULL == dev_state) {
2656 			printk(KERN_INFO
2657 			       "btrfsic: error, lookup dev_state failed!\n");
2658 			btrfsic_block_free(block);
2659 			return NULL;
2660 		}
2661 		block->dev_state = dev_state;
2662 		block->dev_bytenr = block_ctx->dev_bytenr;
2663 		block->logical_bytenr = block_ctx->start;
2664 		block->is_metadata = is_metadata;
2665 		block->is_iodone = is_iodone;
2666 		block->never_written = never_written;
2667 		block->mirror_num = mirror_num;
2668 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2669 			printk(KERN_INFO
2670 			       "New %s%c-block @%llu (%s/%llu/%d)\n",
2671 			       additional_string,
2672 			       btrfsic_get_block_type(state, block),
2673 			       (unsigned long long)block->logical_bytenr,
2674 			       dev_state->name,
2675 			       (unsigned long long)block->dev_bytenr,
2676 			       mirror_num);
2677 		list_add(&block->all_blocks_node, &state->all_blocks_list);
2678 		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2679 		if (NULL != was_created)
2680 			*was_created = 1;
2681 	} else {
2682 		if (NULL != was_created)
2683 			*was_created = 0;
2684 	}
2685 
2686 	return block;
2687 }
2688 
2689 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2690 					   u64 bytenr,
2691 					   struct btrfsic_dev_state *dev_state,
2692 					   u64 dev_bytenr, char *data)
2693 {
2694 	int num_copies;
2695 	int mirror_num;
2696 	int ret;
2697 	struct btrfsic_block_data_ctx block_ctx;
2698 	int match = 0;
2699 
2700 	num_copies = btrfs_num_copies(&state->root->fs_info->mapping_tree,
2701 				      bytenr, PAGE_SIZE);
2702 
2703 	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2704 		ret = btrfsic_map_block(state, bytenr, PAGE_SIZE,
2705 					&block_ctx, mirror_num);
2706 		if (ret) {
2707 			printk(KERN_INFO "btrfsic:"
2708 			       " btrfsic_map_block(logical @%llu,"
2709 			       " mirror %d) failed!\n",
2710 			       (unsigned long long)bytenr, mirror_num);
2711 			continue;
2712 		}
2713 
2714 		if (dev_state->bdev == block_ctx.dev->bdev &&
2715 		    dev_bytenr == block_ctx.dev_bytenr) {
2716 			match++;
2717 			btrfsic_release_block_ctx(&block_ctx);
2718 			break;
2719 		}
2720 		btrfsic_release_block_ctx(&block_ctx);
2721 	}
2722 
2723 	if (!match) {
2724 		printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2725 		       " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2726 		       " phys_bytenr=%llu)!\n",
2727 		       (unsigned long long)bytenr, dev_state->name,
2728 		       (unsigned long long)dev_bytenr);
2729 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2730 			ret = btrfsic_map_block(state, bytenr, PAGE_SIZE,
2731 						&block_ctx, mirror_num);
2732 			if (ret)
2733 				continue;
2734 
2735 			printk(KERN_INFO "Read logical bytenr @%llu maps to"
2736 			       " (%s/%llu/%d)\n",
2737 			       (unsigned long long)bytenr,
2738 			       block_ctx.dev->name,
2739 			       (unsigned long long)block_ctx.dev_bytenr,
2740 			       mirror_num);
2741 		}
2742 		WARN_ON(1);
2743 	}
2744 }
2745 
2746 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2747 		struct block_device *bdev)
2748 {
2749 	struct btrfsic_dev_state *ds;
2750 
2751 	ds = btrfsic_dev_state_hashtable_lookup(bdev,
2752 						&btrfsic_dev_state_hashtable);
2753 	return ds;
2754 }
2755 
2756 int btrfsic_submit_bh(int rw, struct buffer_head *bh)
2757 {
2758 	struct btrfsic_dev_state *dev_state;
2759 
2760 	if (!btrfsic_is_initialized)
2761 		return submit_bh(rw, bh);
2762 
2763 	mutex_lock(&btrfsic_mutex);
2764 	/* since btrfsic_submit_bh() might also be called before
2765 	 * btrfsic_mount(), this might return NULL */
2766 	dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
2767 
2768 	/* Only called to write the superblock (incl. FLUSH/FUA) */
2769 	if (NULL != dev_state &&
2770 	    (rw & WRITE) && bh->b_size > 0) {
2771 		u64 dev_bytenr;
2772 
2773 		dev_bytenr = 4096 * bh->b_blocknr;
2774 		if (dev_state->state->print_mask &
2775 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2776 			printk(KERN_INFO
2777 			       "submit_bh(rw=0x%x, blocknr=%lu (bytenr %llu),"
2778 			       " size=%lu, data=%p, bdev=%p)\n",
2779 			       rw, (unsigned long)bh->b_blocknr,
2780 			       (unsigned long long)dev_bytenr,
2781 			       (unsigned long)bh->b_size, bh->b_data,
2782 			       bh->b_bdev);
2783 		btrfsic_process_written_block(dev_state, dev_bytenr,
2784 					      bh->b_data, bh->b_size, NULL,
2785 					      NULL, bh, rw);
2786 	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
2787 		if (dev_state->state->print_mask &
2788 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2789 			printk(KERN_INFO
2790 			       "submit_bh(rw=0x%x) FLUSH, bdev=%p)\n",
2791 			       rw, bh->b_bdev);
2792 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2793 			if ((dev_state->state->print_mask &
2794 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2795 			      BTRFSIC_PRINT_MASK_VERBOSE)))
2796 				printk(KERN_INFO
2797 				       "btrfsic_submit_bh(%s) with FLUSH"
2798 				       " but dummy block already in use"
2799 				       " (ignored)!\n",
2800 				       dev_state->name);
2801 		} else {
2802 			struct btrfsic_block *const block =
2803 				&dev_state->dummy_block_for_bio_bh_flush;
2804 
2805 			block->is_iodone = 0;
2806 			block->never_written = 0;
2807 			block->iodone_w_error = 0;
2808 			block->flush_gen = dev_state->last_flush_gen + 1;
2809 			block->submit_bio_bh_rw = rw;
2810 			block->orig_bio_bh_private = bh->b_private;
2811 			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2812 			block->next_in_same_bio = NULL;
2813 			bh->b_private = block;
2814 			bh->b_end_io = btrfsic_bh_end_io;
2815 		}
2816 	}
2817 	mutex_unlock(&btrfsic_mutex);
2818 	return submit_bh(rw, bh);
2819 }
2820 
2821 void btrfsic_submit_bio(int rw, struct bio *bio)
2822 {
2823 	struct btrfsic_dev_state *dev_state;
2824 
2825 	if (!btrfsic_is_initialized) {
2826 		submit_bio(rw, bio);
2827 		return;
2828 	}
2829 
2830 	mutex_lock(&btrfsic_mutex);
2831 	/* since btrfsic_submit_bio() is also called before
2832 	 * btrfsic_mount(), this might return NULL */
2833 	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
2834 	if (NULL != dev_state &&
2835 	    (rw & WRITE) && NULL != bio->bi_io_vec) {
2836 		unsigned int i;
2837 		u64 dev_bytenr;
2838 		int bio_is_patched;
2839 
2840 		dev_bytenr = 512 * bio->bi_sector;
2841 		bio_is_patched = 0;
2842 		if (dev_state->state->print_mask &
2843 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2844 			printk(KERN_INFO
2845 			       "submit_bio(rw=0x%x, bi_vcnt=%u,"
2846 			       " bi_sector=%lu (bytenr %llu), bi_bdev=%p)\n",
2847 			       rw, bio->bi_vcnt, (unsigned long)bio->bi_sector,
2848 			       (unsigned long long)dev_bytenr,
2849 			       bio->bi_bdev);
2850 
2851 		for (i = 0; i < bio->bi_vcnt; i++) {
2852 			u8 *mapped_data;
2853 
2854 			mapped_data = kmap(bio->bi_io_vec[i].bv_page);
2855 			if ((BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2856 			     BTRFSIC_PRINT_MASK_VERBOSE) ==
2857 			    (dev_state->state->print_mask &
2858 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2859 			      BTRFSIC_PRINT_MASK_VERBOSE)))
2860 				printk(KERN_INFO
2861 				       "#%u: page=%p, mapped=%p, len=%u,"
2862 				       " offset=%u\n",
2863 				       i, bio->bi_io_vec[i].bv_page,
2864 				       mapped_data,
2865 				       bio->bi_io_vec[i].bv_len,
2866 				       bio->bi_io_vec[i].bv_offset);
2867 			btrfsic_process_written_block(dev_state, dev_bytenr,
2868 						      mapped_data,
2869 						      bio->bi_io_vec[i].bv_len,
2870 						      bio, &bio_is_patched,
2871 						      NULL, rw);
2872 			kunmap(bio->bi_io_vec[i].bv_page);
2873 			dev_bytenr += bio->bi_io_vec[i].bv_len;
2874 		}
2875 	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
2876 		if (dev_state->state->print_mask &
2877 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2878 			printk(KERN_INFO
2879 			       "submit_bio(rw=0x%x) FLUSH, bdev=%p)\n",
2880 			       rw, bio->bi_bdev);
2881 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2882 			if ((dev_state->state->print_mask &
2883 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2884 			      BTRFSIC_PRINT_MASK_VERBOSE)))
2885 				printk(KERN_INFO
2886 				       "btrfsic_submit_bio(%s) with FLUSH"
2887 				       " but dummy block already in use"
2888 				       " (ignored)!\n",
2889 				       dev_state->name);
2890 		} else {
2891 			struct btrfsic_block *const block =
2892 				&dev_state->dummy_block_for_bio_bh_flush;
2893 
2894 			block->is_iodone = 0;
2895 			block->never_written = 0;
2896 			block->iodone_w_error = 0;
2897 			block->flush_gen = dev_state->last_flush_gen + 1;
2898 			block->submit_bio_bh_rw = rw;
2899 			block->orig_bio_bh_private = bio->bi_private;
2900 			block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2901 			block->next_in_same_bio = NULL;
2902 			bio->bi_private = block;
2903 			bio->bi_end_io = btrfsic_bio_end_io;
2904 		}
2905 	}
2906 	mutex_unlock(&btrfsic_mutex);
2907 
2908 	submit_bio(rw, bio);
2909 }
2910 
2911 int btrfsic_mount(struct btrfs_root *root,
2912 		  struct btrfs_fs_devices *fs_devices,
2913 		  int including_extent_data, u32 print_mask)
2914 {
2915 	int ret;
2916 	struct btrfsic_state *state;
2917 	struct list_head *dev_head = &fs_devices->devices;
2918 	struct btrfs_device *device;
2919 
2920 	state = kzalloc(sizeof(*state), GFP_NOFS);
2921 	if (NULL == state) {
2922 		printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
2923 		return -1;
2924 	}
2925 
2926 	if (!btrfsic_is_initialized) {
2927 		mutex_init(&btrfsic_mutex);
2928 		btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
2929 		btrfsic_is_initialized = 1;
2930 	}
2931 	mutex_lock(&btrfsic_mutex);
2932 	state->root = root;
2933 	state->print_mask = print_mask;
2934 	state->include_extent_data = including_extent_data;
2935 	state->csum_size = 0;
2936 	INIT_LIST_HEAD(&state->all_blocks_list);
2937 	btrfsic_block_hashtable_init(&state->block_hashtable);
2938 	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
2939 	state->max_superblock_generation = 0;
2940 	state->latest_superblock = NULL;
2941 
2942 	list_for_each_entry(device, dev_head, dev_list) {
2943 		struct btrfsic_dev_state *ds;
2944 		char *p;
2945 
2946 		if (!device->bdev || !device->name)
2947 			continue;
2948 
2949 		ds = btrfsic_dev_state_alloc();
2950 		if (NULL == ds) {
2951 			printk(KERN_INFO
2952 			       "btrfs check-integrity: kmalloc() failed!\n");
2953 			mutex_unlock(&btrfsic_mutex);
2954 			return -1;
2955 		}
2956 		ds->bdev = device->bdev;
2957 		ds->state = state;
2958 		bdevname(ds->bdev, ds->name);
2959 		ds->name[BDEVNAME_SIZE - 1] = '\0';
2960 		for (p = ds->name; *p != '\0'; p++);
2961 		while (p > ds->name && *p != '/')
2962 			p--;
2963 		if (*p == '/')
2964 			p++;
2965 		strlcpy(ds->name, p, sizeof(ds->name));
2966 		btrfsic_dev_state_hashtable_add(ds,
2967 						&btrfsic_dev_state_hashtable);
2968 	}
2969 
2970 	ret = btrfsic_process_superblock(state, fs_devices);
2971 	if (0 != ret) {
2972 		mutex_unlock(&btrfsic_mutex);
2973 		btrfsic_unmount(root, fs_devices);
2974 		return ret;
2975 	}
2976 
2977 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
2978 		btrfsic_dump_database(state);
2979 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
2980 		btrfsic_dump_tree(state);
2981 
2982 	mutex_unlock(&btrfsic_mutex);
2983 	return 0;
2984 }
2985 
2986 void btrfsic_unmount(struct btrfs_root *root,
2987 		     struct btrfs_fs_devices *fs_devices)
2988 {
2989 	struct list_head *elem_all;
2990 	struct list_head *tmp_all;
2991 	struct btrfsic_state *state;
2992 	struct list_head *dev_head = &fs_devices->devices;
2993 	struct btrfs_device *device;
2994 
2995 	if (!btrfsic_is_initialized)
2996 		return;
2997 
2998 	mutex_lock(&btrfsic_mutex);
2999 
3000 	state = NULL;
3001 	list_for_each_entry(device, dev_head, dev_list) {
3002 		struct btrfsic_dev_state *ds;
3003 
3004 		if (!device->bdev || !device->name)
3005 			continue;
3006 
3007 		ds = btrfsic_dev_state_hashtable_lookup(
3008 				device->bdev,
3009 				&btrfsic_dev_state_hashtable);
3010 		if (NULL != ds) {
3011 			state = ds->state;
3012 			btrfsic_dev_state_hashtable_remove(ds);
3013 			btrfsic_dev_state_free(ds);
3014 		}
3015 	}
3016 
3017 	if (NULL == state) {
3018 		printk(KERN_INFO
3019 		       "btrfsic: error, cannot find state information"
3020 		       " on umount!\n");
3021 		mutex_unlock(&btrfsic_mutex);
3022 		return;
3023 	}
3024 
3025 	/*
3026 	 * Don't care about keeping the lists' state up to date,
3027 	 * just free all memory that was allocated dynamically.
3028 	 * Free the blocks and the block_links.
3029 	 */
3030 	list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3031 		struct btrfsic_block *const b_all =
3032 		    list_entry(elem_all, struct btrfsic_block,
3033 			       all_blocks_node);
3034 		struct list_head *elem_ref_to;
3035 		struct list_head *tmp_ref_to;
3036 
3037 		list_for_each_safe(elem_ref_to, tmp_ref_to,
3038 				   &b_all->ref_to_list) {
3039 			struct btrfsic_block_link *const l =
3040 			    list_entry(elem_ref_to,
3041 				       struct btrfsic_block_link,
3042 				       node_ref_to);
3043 
3044 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3045 				btrfsic_print_rem_link(state, l);
3046 
3047 			l->ref_cnt--;
3048 			if (0 == l->ref_cnt)
3049 				btrfsic_block_link_free(l);
3050 		}
3051 
3052 		if (b_all->is_iodone)
3053 			btrfsic_block_free(b_all);
3054 		else
3055 			printk(KERN_INFO "btrfs: attempt to free %c-block"
3056 			       " @%llu (%s/%llu/%d) on umount which is"
3057 			       " not yet iodone!\n",
3058 			       btrfsic_get_block_type(state, b_all),
3059 			       (unsigned long long)b_all->logical_bytenr,
3060 			       b_all->dev_state->name,
3061 			       (unsigned long long)b_all->dev_bytenr,
3062 			       b_all->mirror_num);
3063 	}
3064 
3065 	mutex_unlock(&btrfsic_mutex);
3066 
3067 	kfree(state);
3068 }
3069