xref: /openbmc/linux/fs/btrfs/check-integrity.c (revision 5bd8e16d)
1 /*
2  * Copyright (C) STRATO AG 2011.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 
19 /*
20  * This module can be used to catch cases when the btrfs kernel
21  * code executes write requests to the disk that bring the file
22  * system in an inconsistent state. In such a state, a power-loss
23  * or kernel panic event would cause that the data on disk is
24  * lost or at least damaged.
25  *
26  * Code is added that examines all block write requests during
27  * runtime (including writes of the super block). Three rules
28  * are verified and an error is printed on violation of the
29  * rules:
30  * 1. It is not allowed to write a disk block which is
31  *    currently referenced by the super block (either directly
32  *    or indirectly).
33  * 2. When a super block is written, it is verified that all
34  *    referenced (directly or indirectly) blocks fulfill the
35  *    following requirements:
36  *    2a. All referenced blocks have either been present when
37  *        the file system was mounted, (i.e., they have been
38  *        referenced by the super block) or they have been
39  *        written since then and the write completion callback
40  *        was called and no write error was indicated and a
41  *        FLUSH request to the device where these blocks are
42  *        located was received and completed.
43  *    2b. All referenced blocks need to have a generation
44  *        number which is equal to the parent's number.
45  *
46  * One issue that was found using this module was that the log
47  * tree on disk became temporarily corrupted because disk blocks
48  * that had been in use for the log tree had been freed and
49  * reused too early, while being referenced by the written super
50  * block.
51  *
52  * The search term in the kernel log that can be used to filter
53  * on the existence of detected integrity issues is
54  * "btrfs: attempt".
55  *
56  * The integrity check is enabled via mount options. These
57  * mount options are only supported if the integrity check
58  * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
59  *
60  * Example #1, apply integrity checks to all metadata:
61  * mount /dev/sdb1 /mnt -o check_int
62  *
63  * Example #2, apply integrity checks to all metadata and
64  * to data extents:
65  * mount /dev/sdb1 /mnt -o check_int_data
66  *
67  * Example #3, apply integrity checks to all metadata and dump
68  * the tree that the super block references to kernel messages
69  * each time after a super block was written:
70  * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
71  *
72  * If the integrity check tool is included and activated in
73  * the mount options, plenty of kernel memory is used, and
74  * plenty of additional CPU cycles are spent. Enabling this
75  * functionality is not intended for normal use. In most
76  * cases, unless you are a btrfs developer who needs to verify
77  * the integrity of (super)-block write requests, do not
78  * enable the config option BTRFS_FS_CHECK_INTEGRITY to
79  * include and compile the integrity check tool.
80  */
81 
82 #include <linux/sched.h>
83 #include <linux/slab.h>
84 #include <linux/buffer_head.h>
85 #include <linux/mutex.h>
86 #include <linux/crc32c.h>
87 #include <linux/genhd.h>
88 #include <linux/blkdev.h>
89 #include "ctree.h"
90 #include "disk-io.h"
91 #include "transaction.h"
92 #include "extent_io.h"
93 #include "volumes.h"
94 #include "print-tree.h"
95 #include "locking.h"
96 #include "check-integrity.h"
97 #include "rcu-string.h"
98 
99 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
100 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
101 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
102 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
103 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
104 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
105 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
106 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)	/* in characters,
107 							 * excluding " [...]" */
108 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
109 
110 /*
111  * The definition of the bitmask fields for the print_mask.
112  * They are specified with the mount option check_integrity_print_mask.
113  */
114 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE			0x00000001
115 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION		0x00000002
116 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE			0x00000004
117 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE			0x00000008
118 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH			0x00000010
119 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH			0x00000020
120 #define BTRFSIC_PRINT_MASK_VERBOSE				0x00000040
121 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE				0x00000080
122 #define BTRFSIC_PRINT_MASK_INITIAL_TREE				0x00000100
123 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES			0x00000200
124 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE			0x00000400
125 #define BTRFSIC_PRINT_MASK_NUM_COPIES				0x00000800
126 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS		0x00001000
127 
128 struct btrfsic_dev_state;
129 struct btrfsic_state;
130 
131 struct btrfsic_block {
132 	u32 magic_num;		/* only used for debug purposes */
133 	unsigned int is_metadata:1;	/* if it is meta-data, not data-data */
134 	unsigned int is_superblock:1;	/* if it is one of the superblocks */
135 	unsigned int is_iodone:1;	/* if is done by lower subsystem */
136 	unsigned int iodone_w_error:1;	/* error was indicated to endio */
137 	unsigned int never_written:1;	/* block was added because it was
138 					 * referenced, not because it was
139 					 * written */
140 	unsigned int mirror_num;	/* large enough to hold
141 					 * BTRFS_SUPER_MIRROR_MAX */
142 	struct btrfsic_dev_state *dev_state;
143 	u64 dev_bytenr;		/* key, physical byte num on disk */
144 	u64 logical_bytenr;	/* logical byte num on disk */
145 	u64 generation;
146 	struct btrfs_disk_key disk_key;	/* extra info to print in case of
147 					 * issues, will not always be correct */
148 	struct list_head collision_resolving_node;	/* list node */
149 	struct list_head all_blocks_node;	/* list node */
150 
151 	/* the following two lists contain block_link items */
152 	struct list_head ref_to_list;	/* list */
153 	struct list_head ref_from_list;	/* list */
154 	struct btrfsic_block *next_in_same_bio;
155 	void *orig_bio_bh_private;
156 	union {
157 		bio_end_io_t *bio;
158 		bh_end_io_t *bh;
159 	} orig_bio_bh_end_io;
160 	int submit_bio_bh_rw;
161 	u64 flush_gen; /* only valid if !never_written */
162 };
163 
164 /*
165  * Elements of this type are allocated dynamically and required because
166  * each block object can refer to and can be ref from multiple blocks.
167  * The key to lookup them in the hashtable is the dev_bytenr of
168  * the block ref to plus the one from the block refered from.
169  * The fact that they are searchable via a hashtable and that a
170  * ref_cnt is maintained is not required for the btrfs integrity
171  * check algorithm itself, it is only used to make the output more
172  * beautiful in case that an error is detected (an error is defined
173  * as a write operation to a block while that block is still referenced).
174  */
175 struct btrfsic_block_link {
176 	u32 magic_num;		/* only used for debug purposes */
177 	u32 ref_cnt;
178 	struct list_head node_ref_to;	/* list node */
179 	struct list_head node_ref_from;	/* list node */
180 	struct list_head collision_resolving_node;	/* list node */
181 	struct btrfsic_block *block_ref_to;
182 	struct btrfsic_block *block_ref_from;
183 	u64 parent_generation;
184 };
185 
186 struct btrfsic_dev_state {
187 	u32 magic_num;		/* only used for debug purposes */
188 	struct block_device *bdev;
189 	struct btrfsic_state *state;
190 	struct list_head collision_resolving_node;	/* list node */
191 	struct btrfsic_block dummy_block_for_bio_bh_flush;
192 	u64 last_flush_gen;
193 	char name[BDEVNAME_SIZE];
194 };
195 
196 struct btrfsic_block_hashtable {
197 	struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
198 };
199 
200 struct btrfsic_block_link_hashtable {
201 	struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
202 };
203 
204 struct btrfsic_dev_state_hashtable {
205 	struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
206 };
207 
208 struct btrfsic_block_data_ctx {
209 	u64 start;		/* virtual bytenr */
210 	u64 dev_bytenr;		/* physical bytenr on device */
211 	u32 len;
212 	struct btrfsic_dev_state *dev;
213 	char **datav;
214 	struct page **pagev;
215 	void *mem_to_free;
216 };
217 
218 /* This structure is used to implement recursion without occupying
219  * any stack space, refer to btrfsic_process_metablock() */
220 struct btrfsic_stack_frame {
221 	u32 magic;
222 	u32 nr;
223 	int error;
224 	int i;
225 	int limit_nesting;
226 	int num_copies;
227 	int mirror_num;
228 	struct btrfsic_block *block;
229 	struct btrfsic_block_data_ctx *block_ctx;
230 	struct btrfsic_block *next_block;
231 	struct btrfsic_block_data_ctx next_block_ctx;
232 	struct btrfs_header *hdr;
233 	struct btrfsic_stack_frame *prev;
234 };
235 
236 /* Some state per mounted filesystem */
237 struct btrfsic_state {
238 	u32 print_mask;
239 	int include_extent_data;
240 	int csum_size;
241 	struct list_head all_blocks_list;
242 	struct btrfsic_block_hashtable block_hashtable;
243 	struct btrfsic_block_link_hashtable block_link_hashtable;
244 	struct btrfs_root *root;
245 	u64 max_superblock_generation;
246 	struct btrfsic_block *latest_superblock;
247 	u32 metablock_size;
248 	u32 datablock_size;
249 };
250 
251 static void btrfsic_block_init(struct btrfsic_block *b);
252 static struct btrfsic_block *btrfsic_block_alloc(void);
253 static void btrfsic_block_free(struct btrfsic_block *b);
254 static void btrfsic_block_link_init(struct btrfsic_block_link *n);
255 static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
256 static void btrfsic_block_link_free(struct btrfsic_block_link *n);
257 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
258 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
259 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
260 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
261 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
262 					struct btrfsic_block_hashtable *h);
263 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
264 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
265 		struct block_device *bdev,
266 		u64 dev_bytenr,
267 		struct btrfsic_block_hashtable *h);
268 static void btrfsic_block_link_hashtable_init(
269 		struct btrfsic_block_link_hashtable *h);
270 static void btrfsic_block_link_hashtable_add(
271 		struct btrfsic_block_link *l,
272 		struct btrfsic_block_link_hashtable *h);
273 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
274 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
275 		struct block_device *bdev_ref_to,
276 		u64 dev_bytenr_ref_to,
277 		struct block_device *bdev_ref_from,
278 		u64 dev_bytenr_ref_from,
279 		struct btrfsic_block_link_hashtable *h);
280 static void btrfsic_dev_state_hashtable_init(
281 		struct btrfsic_dev_state_hashtable *h);
282 static void btrfsic_dev_state_hashtable_add(
283 		struct btrfsic_dev_state *ds,
284 		struct btrfsic_dev_state_hashtable *h);
285 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
286 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
287 		struct block_device *bdev,
288 		struct btrfsic_dev_state_hashtable *h);
289 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
290 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
291 static int btrfsic_process_superblock(struct btrfsic_state *state,
292 				      struct btrfs_fs_devices *fs_devices);
293 static int btrfsic_process_metablock(struct btrfsic_state *state,
294 				     struct btrfsic_block *block,
295 				     struct btrfsic_block_data_ctx *block_ctx,
296 				     int limit_nesting, int force_iodone_flag);
297 static void btrfsic_read_from_block_data(
298 	struct btrfsic_block_data_ctx *block_ctx,
299 	void *dst, u32 offset, size_t len);
300 static int btrfsic_create_link_to_next_block(
301 		struct btrfsic_state *state,
302 		struct btrfsic_block *block,
303 		struct btrfsic_block_data_ctx
304 		*block_ctx, u64 next_bytenr,
305 		int limit_nesting,
306 		struct btrfsic_block_data_ctx *next_block_ctx,
307 		struct btrfsic_block **next_blockp,
308 		int force_iodone_flag,
309 		int *num_copiesp, int *mirror_nump,
310 		struct btrfs_disk_key *disk_key,
311 		u64 parent_generation);
312 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
313 				      struct btrfsic_block *block,
314 				      struct btrfsic_block_data_ctx *block_ctx,
315 				      u32 item_offset, int force_iodone_flag);
316 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
317 			     struct btrfsic_block_data_ctx *block_ctx_out,
318 			     int mirror_num);
319 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
320 				  u32 len, struct block_device *bdev,
321 				  struct btrfsic_block_data_ctx *block_ctx_out);
322 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
323 static int btrfsic_read_block(struct btrfsic_state *state,
324 			      struct btrfsic_block_data_ctx *block_ctx);
325 static void btrfsic_dump_database(struct btrfsic_state *state);
326 static void btrfsic_complete_bio_end_io(struct bio *bio, int err);
327 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
328 				     char **datav, unsigned int num_pages);
329 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
330 					  u64 dev_bytenr, char **mapped_datav,
331 					  unsigned int num_pages,
332 					  struct bio *bio, int *bio_is_patched,
333 					  struct buffer_head *bh,
334 					  int submit_bio_bh_rw);
335 static int btrfsic_process_written_superblock(
336 		struct btrfsic_state *state,
337 		struct btrfsic_block *const block,
338 		struct btrfs_super_block *const super_hdr);
339 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
340 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
341 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
342 					      const struct btrfsic_block *block,
343 					      int recursion_level);
344 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
345 					struct btrfsic_block *const block,
346 					int recursion_level);
347 static void btrfsic_print_add_link(const struct btrfsic_state *state,
348 				   const struct btrfsic_block_link *l);
349 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
350 				   const struct btrfsic_block_link *l);
351 static char btrfsic_get_block_type(const struct btrfsic_state *state,
352 				   const struct btrfsic_block *block);
353 static void btrfsic_dump_tree(const struct btrfsic_state *state);
354 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
355 				  const struct btrfsic_block *block,
356 				  int indent_level);
357 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
358 		struct btrfsic_state *state,
359 		struct btrfsic_block_data_ctx *next_block_ctx,
360 		struct btrfsic_block *next_block,
361 		struct btrfsic_block *from_block,
362 		u64 parent_generation);
363 static struct btrfsic_block *btrfsic_block_lookup_or_add(
364 		struct btrfsic_state *state,
365 		struct btrfsic_block_data_ctx *block_ctx,
366 		const char *additional_string,
367 		int is_metadata,
368 		int is_iodone,
369 		int never_written,
370 		int mirror_num,
371 		int *was_created);
372 static int btrfsic_process_superblock_dev_mirror(
373 		struct btrfsic_state *state,
374 		struct btrfsic_dev_state *dev_state,
375 		struct btrfs_device *device,
376 		int superblock_mirror_num,
377 		struct btrfsic_dev_state **selected_dev_state,
378 		struct btrfs_super_block *selected_super);
379 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
380 		struct block_device *bdev);
381 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
382 					   u64 bytenr,
383 					   struct btrfsic_dev_state *dev_state,
384 					   u64 dev_bytenr);
385 
386 static struct mutex btrfsic_mutex;
387 static int btrfsic_is_initialized;
388 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
389 
390 
391 static void btrfsic_block_init(struct btrfsic_block *b)
392 {
393 	b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
394 	b->dev_state = NULL;
395 	b->dev_bytenr = 0;
396 	b->logical_bytenr = 0;
397 	b->generation = BTRFSIC_GENERATION_UNKNOWN;
398 	b->disk_key.objectid = 0;
399 	b->disk_key.type = 0;
400 	b->disk_key.offset = 0;
401 	b->is_metadata = 0;
402 	b->is_superblock = 0;
403 	b->is_iodone = 0;
404 	b->iodone_w_error = 0;
405 	b->never_written = 0;
406 	b->mirror_num = 0;
407 	b->next_in_same_bio = NULL;
408 	b->orig_bio_bh_private = NULL;
409 	b->orig_bio_bh_end_io.bio = NULL;
410 	INIT_LIST_HEAD(&b->collision_resolving_node);
411 	INIT_LIST_HEAD(&b->all_blocks_node);
412 	INIT_LIST_HEAD(&b->ref_to_list);
413 	INIT_LIST_HEAD(&b->ref_from_list);
414 	b->submit_bio_bh_rw = 0;
415 	b->flush_gen = 0;
416 }
417 
418 static struct btrfsic_block *btrfsic_block_alloc(void)
419 {
420 	struct btrfsic_block *b;
421 
422 	b = kzalloc(sizeof(*b), GFP_NOFS);
423 	if (NULL != b)
424 		btrfsic_block_init(b);
425 
426 	return b;
427 }
428 
429 static void btrfsic_block_free(struct btrfsic_block *b)
430 {
431 	BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
432 	kfree(b);
433 }
434 
435 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
436 {
437 	l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
438 	l->ref_cnt = 1;
439 	INIT_LIST_HEAD(&l->node_ref_to);
440 	INIT_LIST_HEAD(&l->node_ref_from);
441 	INIT_LIST_HEAD(&l->collision_resolving_node);
442 	l->block_ref_to = NULL;
443 	l->block_ref_from = NULL;
444 }
445 
446 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
447 {
448 	struct btrfsic_block_link *l;
449 
450 	l = kzalloc(sizeof(*l), GFP_NOFS);
451 	if (NULL != l)
452 		btrfsic_block_link_init(l);
453 
454 	return l;
455 }
456 
457 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
458 {
459 	BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
460 	kfree(l);
461 }
462 
463 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
464 {
465 	ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
466 	ds->bdev = NULL;
467 	ds->state = NULL;
468 	ds->name[0] = '\0';
469 	INIT_LIST_HEAD(&ds->collision_resolving_node);
470 	ds->last_flush_gen = 0;
471 	btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
472 	ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
473 	ds->dummy_block_for_bio_bh_flush.dev_state = ds;
474 }
475 
476 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
477 {
478 	struct btrfsic_dev_state *ds;
479 
480 	ds = kzalloc(sizeof(*ds), GFP_NOFS);
481 	if (NULL != ds)
482 		btrfsic_dev_state_init(ds);
483 
484 	return ds;
485 }
486 
487 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
488 {
489 	BUG_ON(!(NULL == ds ||
490 		 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
491 	kfree(ds);
492 }
493 
494 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
495 {
496 	int i;
497 
498 	for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
499 		INIT_LIST_HEAD(h->table + i);
500 }
501 
502 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
503 					struct btrfsic_block_hashtable *h)
504 {
505 	const unsigned int hashval =
506 	    (((unsigned int)(b->dev_bytenr >> 16)) ^
507 	     ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
508 	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
509 
510 	list_add(&b->collision_resolving_node, h->table + hashval);
511 }
512 
513 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
514 {
515 	list_del(&b->collision_resolving_node);
516 }
517 
518 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
519 		struct block_device *bdev,
520 		u64 dev_bytenr,
521 		struct btrfsic_block_hashtable *h)
522 {
523 	const unsigned int hashval =
524 	    (((unsigned int)(dev_bytenr >> 16)) ^
525 	     ((unsigned int)((uintptr_t)bdev))) &
526 	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
527 	struct list_head *elem;
528 
529 	list_for_each(elem, h->table + hashval) {
530 		struct btrfsic_block *const b =
531 		    list_entry(elem, struct btrfsic_block,
532 			       collision_resolving_node);
533 
534 		if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
535 			return b;
536 	}
537 
538 	return NULL;
539 }
540 
541 static void btrfsic_block_link_hashtable_init(
542 		struct btrfsic_block_link_hashtable *h)
543 {
544 	int i;
545 
546 	for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
547 		INIT_LIST_HEAD(h->table + i);
548 }
549 
550 static void btrfsic_block_link_hashtable_add(
551 		struct btrfsic_block_link *l,
552 		struct btrfsic_block_link_hashtable *h)
553 {
554 	const unsigned int hashval =
555 	    (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
556 	     ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
557 	     ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
558 	     ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
559 	     & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
560 
561 	BUG_ON(NULL == l->block_ref_to);
562 	BUG_ON(NULL == l->block_ref_from);
563 	list_add(&l->collision_resolving_node, h->table + hashval);
564 }
565 
566 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
567 {
568 	list_del(&l->collision_resolving_node);
569 }
570 
571 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
572 		struct block_device *bdev_ref_to,
573 		u64 dev_bytenr_ref_to,
574 		struct block_device *bdev_ref_from,
575 		u64 dev_bytenr_ref_from,
576 		struct btrfsic_block_link_hashtable *h)
577 {
578 	const unsigned int hashval =
579 	    (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
580 	     ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
581 	     ((unsigned int)((uintptr_t)bdev_ref_to)) ^
582 	     ((unsigned int)((uintptr_t)bdev_ref_from))) &
583 	     (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
584 	struct list_head *elem;
585 
586 	list_for_each(elem, h->table + hashval) {
587 		struct btrfsic_block_link *const l =
588 		    list_entry(elem, struct btrfsic_block_link,
589 			       collision_resolving_node);
590 
591 		BUG_ON(NULL == l->block_ref_to);
592 		BUG_ON(NULL == l->block_ref_from);
593 		if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
594 		    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
595 		    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
596 		    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
597 			return l;
598 	}
599 
600 	return NULL;
601 }
602 
603 static void btrfsic_dev_state_hashtable_init(
604 		struct btrfsic_dev_state_hashtable *h)
605 {
606 	int i;
607 
608 	for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
609 		INIT_LIST_HEAD(h->table + i);
610 }
611 
612 static void btrfsic_dev_state_hashtable_add(
613 		struct btrfsic_dev_state *ds,
614 		struct btrfsic_dev_state_hashtable *h)
615 {
616 	const unsigned int hashval =
617 	    (((unsigned int)((uintptr_t)ds->bdev)) &
618 	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
619 
620 	list_add(&ds->collision_resolving_node, h->table + hashval);
621 }
622 
623 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
624 {
625 	list_del(&ds->collision_resolving_node);
626 }
627 
628 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
629 		struct block_device *bdev,
630 		struct btrfsic_dev_state_hashtable *h)
631 {
632 	const unsigned int hashval =
633 	    (((unsigned int)((uintptr_t)bdev)) &
634 	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
635 	struct list_head *elem;
636 
637 	list_for_each(elem, h->table + hashval) {
638 		struct btrfsic_dev_state *const ds =
639 		    list_entry(elem, struct btrfsic_dev_state,
640 			       collision_resolving_node);
641 
642 		if (ds->bdev == bdev)
643 			return ds;
644 	}
645 
646 	return NULL;
647 }
648 
649 static int btrfsic_process_superblock(struct btrfsic_state *state,
650 				      struct btrfs_fs_devices *fs_devices)
651 {
652 	int ret = 0;
653 	struct btrfs_super_block *selected_super;
654 	struct list_head *dev_head = &fs_devices->devices;
655 	struct btrfs_device *device;
656 	struct btrfsic_dev_state *selected_dev_state = NULL;
657 	int pass;
658 
659 	BUG_ON(NULL == state);
660 	selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
661 	if (NULL == selected_super) {
662 		printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
663 		return -1;
664 	}
665 
666 	list_for_each_entry(device, dev_head, dev_list) {
667 		int i;
668 		struct btrfsic_dev_state *dev_state;
669 
670 		if (!device->bdev || !device->name)
671 			continue;
672 
673 		dev_state = btrfsic_dev_state_lookup(device->bdev);
674 		BUG_ON(NULL == dev_state);
675 		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
676 			ret = btrfsic_process_superblock_dev_mirror(
677 					state, dev_state, device, i,
678 					&selected_dev_state, selected_super);
679 			if (0 != ret && 0 == i) {
680 				kfree(selected_super);
681 				return ret;
682 			}
683 		}
684 	}
685 
686 	if (NULL == state->latest_superblock) {
687 		printk(KERN_INFO "btrfsic: no superblock found!\n");
688 		kfree(selected_super);
689 		return -1;
690 	}
691 
692 	state->csum_size = btrfs_super_csum_size(selected_super);
693 
694 	for (pass = 0; pass < 3; pass++) {
695 		int num_copies;
696 		int mirror_num;
697 		u64 next_bytenr;
698 
699 		switch (pass) {
700 		case 0:
701 			next_bytenr = btrfs_super_root(selected_super);
702 			if (state->print_mask &
703 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
704 				printk(KERN_INFO "root@%llu\n", next_bytenr);
705 			break;
706 		case 1:
707 			next_bytenr = btrfs_super_chunk_root(selected_super);
708 			if (state->print_mask &
709 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
710 				printk(KERN_INFO "chunk@%llu\n", next_bytenr);
711 			break;
712 		case 2:
713 			next_bytenr = btrfs_super_log_root(selected_super);
714 			if (0 == next_bytenr)
715 				continue;
716 			if (state->print_mask &
717 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
718 				printk(KERN_INFO "log@%llu\n", next_bytenr);
719 			break;
720 		}
721 
722 		num_copies =
723 		    btrfs_num_copies(state->root->fs_info,
724 				     next_bytenr, state->metablock_size);
725 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
726 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
727 			       next_bytenr, num_copies);
728 
729 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
730 			struct btrfsic_block *next_block;
731 			struct btrfsic_block_data_ctx tmp_next_block_ctx;
732 			struct btrfsic_block_link *l;
733 
734 			ret = btrfsic_map_block(state, next_bytenr,
735 						state->metablock_size,
736 						&tmp_next_block_ctx,
737 						mirror_num);
738 			if (ret) {
739 				printk(KERN_INFO "btrfsic:"
740 				       " btrfsic_map_block(root @%llu,"
741 				       " mirror %d) failed!\n",
742 				       next_bytenr, mirror_num);
743 				kfree(selected_super);
744 				return -1;
745 			}
746 
747 			next_block = btrfsic_block_hashtable_lookup(
748 					tmp_next_block_ctx.dev->bdev,
749 					tmp_next_block_ctx.dev_bytenr,
750 					&state->block_hashtable);
751 			BUG_ON(NULL == next_block);
752 
753 			l = btrfsic_block_link_hashtable_lookup(
754 					tmp_next_block_ctx.dev->bdev,
755 					tmp_next_block_ctx.dev_bytenr,
756 					state->latest_superblock->dev_state->
757 					bdev,
758 					state->latest_superblock->dev_bytenr,
759 					&state->block_link_hashtable);
760 			BUG_ON(NULL == l);
761 
762 			ret = btrfsic_read_block(state, &tmp_next_block_ctx);
763 			if (ret < (int)PAGE_CACHE_SIZE) {
764 				printk(KERN_INFO
765 				       "btrfsic: read @logical %llu failed!\n",
766 				       tmp_next_block_ctx.start);
767 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
768 				kfree(selected_super);
769 				return -1;
770 			}
771 
772 			ret = btrfsic_process_metablock(state,
773 							next_block,
774 							&tmp_next_block_ctx,
775 							BTRFS_MAX_LEVEL + 3, 1);
776 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
777 		}
778 	}
779 
780 	kfree(selected_super);
781 	return ret;
782 }
783 
784 static int btrfsic_process_superblock_dev_mirror(
785 		struct btrfsic_state *state,
786 		struct btrfsic_dev_state *dev_state,
787 		struct btrfs_device *device,
788 		int superblock_mirror_num,
789 		struct btrfsic_dev_state **selected_dev_state,
790 		struct btrfs_super_block *selected_super)
791 {
792 	struct btrfs_super_block *super_tmp;
793 	u64 dev_bytenr;
794 	struct buffer_head *bh;
795 	struct btrfsic_block *superblock_tmp;
796 	int pass;
797 	struct block_device *const superblock_bdev = device->bdev;
798 
799 	/* super block bytenr is always the unmapped device bytenr */
800 	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
801 	if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
802 		return -1;
803 	bh = __bread(superblock_bdev, dev_bytenr / 4096,
804 		     BTRFS_SUPER_INFO_SIZE);
805 	if (NULL == bh)
806 		return -1;
807 	super_tmp = (struct btrfs_super_block *)
808 	    (bh->b_data + (dev_bytenr & 4095));
809 
810 	if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
811 	    btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
812 	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
813 	    btrfs_super_nodesize(super_tmp) != state->metablock_size ||
814 	    btrfs_super_leafsize(super_tmp) != state->metablock_size ||
815 	    btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
816 		brelse(bh);
817 		return 0;
818 	}
819 
820 	superblock_tmp =
821 	    btrfsic_block_hashtable_lookup(superblock_bdev,
822 					   dev_bytenr,
823 					   &state->block_hashtable);
824 	if (NULL == superblock_tmp) {
825 		superblock_tmp = btrfsic_block_alloc();
826 		if (NULL == superblock_tmp) {
827 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
828 			brelse(bh);
829 			return -1;
830 		}
831 		/* for superblock, only the dev_bytenr makes sense */
832 		superblock_tmp->dev_bytenr = dev_bytenr;
833 		superblock_tmp->dev_state = dev_state;
834 		superblock_tmp->logical_bytenr = dev_bytenr;
835 		superblock_tmp->generation = btrfs_super_generation(super_tmp);
836 		superblock_tmp->is_metadata = 1;
837 		superblock_tmp->is_superblock = 1;
838 		superblock_tmp->is_iodone = 1;
839 		superblock_tmp->never_written = 0;
840 		superblock_tmp->mirror_num = 1 + superblock_mirror_num;
841 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
842 			printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
843 				     " @%llu (%s/%llu/%d)\n",
844 				     superblock_bdev,
845 				     rcu_str_deref(device->name), dev_bytenr,
846 				     dev_state->name, dev_bytenr,
847 				     superblock_mirror_num);
848 		list_add(&superblock_tmp->all_blocks_node,
849 			 &state->all_blocks_list);
850 		btrfsic_block_hashtable_add(superblock_tmp,
851 					    &state->block_hashtable);
852 	}
853 
854 	/* select the one with the highest generation field */
855 	if (btrfs_super_generation(super_tmp) >
856 	    state->max_superblock_generation ||
857 	    0 == state->max_superblock_generation) {
858 		memcpy(selected_super, super_tmp, sizeof(*selected_super));
859 		*selected_dev_state = dev_state;
860 		state->max_superblock_generation =
861 		    btrfs_super_generation(super_tmp);
862 		state->latest_superblock = superblock_tmp;
863 	}
864 
865 	for (pass = 0; pass < 3; pass++) {
866 		u64 next_bytenr;
867 		int num_copies;
868 		int mirror_num;
869 		const char *additional_string = NULL;
870 		struct btrfs_disk_key tmp_disk_key;
871 
872 		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
873 		tmp_disk_key.offset = 0;
874 		switch (pass) {
875 		case 0:
876 			btrfs_set_disk_key_objectid(&tmp_disk_key,
877 						    BTRFS_ROOT_TREE_OBJECTID);
878 			additional_string = "initial root ";
879 			next_bytenr = btrfs_super_root(super_tmp);
880 			break;
881 		case 1:
882 			btrfs_set_disk_key_objectid(&tmp_disk_key,
883 						    BTRFS_CHUNK_TREE_OBJECTID);
884 			additional_string = "initial chunk ";
885 			next_bytenr = btrfs_super_chunk_root(super_tmp);
886 			break;
887 		case 2:
888 			btrfs_set_disk_key_objectid(&tmp_disk_key,
889 						    BTRFS_TREE_LOG_OBJECTID);
890 			additional_string = "initial log ";
891 			next_bytenr = btrfs_super_log_root(super_tmp);
892 			if (0 == next_bytenr)
893 				continue;
894 			break;
895 		}
896 
897 		num_copies =
898 		    btrfs_num_copies(state->root->fs_info,
899 				     next_bytenr, state->metablock_size);
900 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
901 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
902 			       next_bytenr, num_copies);
903 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
904 			struct btrfsic_block *next_block;
905 			struct btrfsic_block_data_ctx tmp_next_block_ctx;
906 			struct btrfsic_block_link *l;
907 
908 			if (btrfsic_map_block(state, next_bytenr,
909 					      state->metablock_size,
910 					      &tmp_next_block_ctx,
911 					      mirror_num)) {
912 				printk(KERN_INFO "btrfsic: btrfsic_map_block("
913 				       "bytenr @%llu, mirror %d) failed!\n",
914 				       next_bytenr, mirror_num);
915 				brelse(bh);
916 				return -1;
917 			}
918 
919 			next_block = btrfsic_block_lookup_or_add(
920 					state, &tmp_next_block_ctx,
921 					additional_string, 1, 1, 0,
922 					mirror_num, NULL);
923 			if (NULL == next_block) {
924 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
925 				brelse(bh);
926 				return -1;
927 			}
928 
929 			next_block->disk_key = tmp_disk_key;
930 			next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
931 			l = btrfsic_block_link_lookup_or_add(
932 					state, &tmp_next_block_ctx,
933 					next_block, superblock_tmp,
934 					BTRFSIC_GENERATION_UNKNOWN);
935 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
936 			if (NULL == l) {
937 				brelse(bh);
938 				return -1;
939 			}
940 		}
941 	}
942 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
943 		btrfsic_dump_tree_sub(state, superblock_tmp, 0);
944 
945 	brelse(bh);
946 	return 0;
947 }
948 
949 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
950 {
951 	struct btrfsic_stack_frame *sf;
952 
953 	sf = kzalloc(sizeof(*sf), GFP_NOFS);
954 	if (NULL == sf)
955 		printk(KERN_INFO "btrfsic: alloc memory failed!\n");
956 	else
957 		sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
958 	return sf;
959 }
960 
961 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
962 {
963 	BUG_ON(!(NULL == sf ||
964 		 BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
965 	kfree(sf);
966 }
967 
968 static int btrfsic_process_metablock(
969 		struct btrfsic_state *state,
970 		struct btrfsic_block *const first_block,
971 		struct btrfsic_block_data_ctx *const first_block_ctx,
972 		int first_limit_nesting, int force_iodone_flag)
973 {
974 	struct btrfsic_stack_frame initial_stack_frame = { 0 };
975 	struct btrfsic_stack_frame *sf;
976 	struct btrfsic_stack_frame *next_stack;
977 	struct btrfs_header *const first_hdr =
978 		(struct btrfs_header *)first_block_ctx->datav[0];
979 
980 	BUG_ON(!first_hdr);
981 	sf = &initial_stack_frame;
982 	sf->error = 0;
983 	sf->i = -1;
984 	sf->limit_nesting = first_limit_nesting;
985 	sf->block = first_block;
986 	sf->block_ctx = first_block_ctx;
987 	sf->next_block = NULL;
988 	sf->hdr = first_hdr;
989 	sf->prev = NULL;
990 
991 continue_with_new_stack_frame:
992 	sf->block->generation = le64_to_cpu(sf->hdr->generation);
993 	if (0 == sf->hdr->level) {
994 		struct btrfs_leaf *const leafhdr =
995 		    (struct btrfs_leaf *)sf->hdr;
996 
997 		if (-1 == sf->i) {
998 			sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
999 
1000 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1001 				printk(KERN_INFO
1002 				       "leaf %llu items %d generation %llu"
1003 				       " owner %llu\n",
1004 				       sf->block_ctx->start, sf->nr,
1005 				       btrfs_stack_header_generation(
1006 					       &leafhdr->header),
1007 				       btrfs_stack_header_owner(
1008 					       &leafhdr->header));
1009 		}
1010 
1011 continue_with_current_leaf_stack_frame:
1012 		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1013 			sf->i++;
1014 			sf->num_copies = 0;
1015 		}
1016 
1017 		if (sf->i < sf->nr) {
1018 			struct btrfs_item disk_item;
1019 			u32 disk_item_offset =
1020 				(uintptr_t)(leafhdr->items + sf->i) -
1021 				(uintptr_t)leafhdr;
1022 			struct btrfs_disk_key *disk_key;
1023 			u8 type;
1024 			u32 item_offset;
1025 			u32 item_size;
1026 
1027 			if (disk_item_offset + sizeof(struct btrfs_item) >
1028 			    sf->block_ctx->len) {
1029 leaf_item_out_of_bounce_error:
1030 				printk(KERN_INFO
1031 				       "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1032 				       sf->block_ctx->start,
1033 				       sf->block_ctx->dev->name);
1034 				goto one_stack_frame_backwards;
1035 			}
1036 			btrfsic_read_from_block_data(sf->block_ctx,
1037 						     &disk_item,
1038 						     disk_item_offset,
1039 						     sizeof(struct btrfs_item));
1040 			item_offset = btrfs_stack_item_offset(&disk_item);
1041 			item_size = btrfs_stack_item_offset(&disk_item);
1042 			disk_key = &disk_item.key;
1043 			type = btrfs_disk_key_type(disk_key);
1044 
1045 			if (BTRFS_ROOT_ITEM_KEY == type) {
1046 				struct btrfs_root_item root_item;
1047 				u32 root_item_offset;
1048 				u64 next_bytenr;
1049 
1050 				root_item_offset = item_offset +
1051 					offsetof(struct btrfs_leaf, items);
1052 				if (root_item_offset + item_size >
1053 				    sf->block_ctx->len)
1054 					goto leaf_item_out_of_bounce_error;
1055 				btrfsic_read_from_block_data(
1056 					sf->block_ctx, &root_item,
1057 					root_item_offset,
1058 					item_size);
1059 				next_bytenr = btrfs_root_bytenr(&root_item);
1060 
1061 				sf->error =
1062 				    btrfsic_create_link_to_next_block(
1063 						state,
1064 						sf->block,
1065 						sf->block_ctx,
1066 						next_bytenr,
1067 						sf->limit_nesting,
1068 						&sf->next_block_ctx,
1069 						&sf->next_block,
1070 						force_iodone_flag,
1071 						&sf->num_copies,
1072 						&sf->mirror_num,
1073 						disk_key,
1074 						btrfs_root_generation(
1075 						&root_item));
1076 				if (sf->error)
1077 					goto one_stack_frame_backwards;
1078 
1079 				if (NULL != sf->next_block) {
1080 					struct btrfs_header *const next_hdr =
1081 					    (struct btrfs_header *)
1082 					    sf->next_block_ctx.datav[0];
1083 
1084 					next_stack =
1085 					    btrfsic_stack_frame_alloc();
1086 					if (NULL == next_stack) {
1087 						btrfsic_release_block_ctx(
1088 								&sf->
1089 								next_block_ctx);
1090 						goto one_stack_frame_backwards;
1091 					}
1092 
1093 					next_stack->i = -1;
1094 					next_stack->block = sf->next_block;
1095 					next_stack->block_ctx =
1096 					    &sf->next_block_ctx;
1097 					next_stack->next_block = NULL;
1098 					next_stack->hdr = next_hdr;
1099 					next_stack->limit_nesting =
1100 					    sf->limit_nesting - 1;
1101 					next_stack->prev = sf;
1102 					sf = next_stack;
1103 					goto continue_with_new_stack_frame;
1104 				}
1105 			} else if (BTRFS_EXTENT_DATA_KEY == type &&
1106 				   state->include_extent_data) {
1107 				sf->error = btrfsic_handle_extent_data(
1108 						state,
1109 						sf->block,
1110 						sf->block_ctx,
1111 						item_offset,
1112 						force_iodone_flag);
1113 				if (sf->error)
1114 					goto one_stack_frame_backwards;
1115 			}
1116 
1117 			goto continue_with_current_leaf_stack_frame;
1118 		}
1119 	} else {
1120 		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1121 
1122 		if (-1 == sf->i) {
1123 			sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1124 
1125 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1126 				printk(KERN_INFO "node %llu level %d items %d"
1127 				       " generation %llu owner %llu\n",
1128 				       sf->block_ctx->start,
1129 				       nodehdr->header.level, sf->nr,
1130 				       btrfs_stack_header_generation(
1131 				       &nodehdr->header),
1132 				       btrfs_stack_header_owner(
1133 				       &nodehdr->header));
1134 		}
1135 
1136 continue_with_current_node_stack_frame:
1137 		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1138 			sf->i++;
1139 			sf->num_copies = 0;
1140 		}
1141 
1142 		if (sf->i < sf->nr) {
1143 			struct btrfs_key_ptr key_ptr;
1144 			u32 key_ptr_offset;
1145 			u64 next_bytenr;
1146 
1147 			key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1148 					  (uintptr_t)nodehdr;
1149 			if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1150 			    sf->block_ctx->len) {
1151 				printk(KERN_INFO
1152 				       "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1153 				       sf->block_ctx->start,
1154 				       sf->block_ctx->dev->name);
1155 				goto one_stack_frame_backwards;
1156 			}
1157 			btrfsic_read_from_block_data(
1158 				sf->block_ctx, &key_ptr, key_ptr_offset,
1159 				sizeof(struct btrfs_key_ptr));
1160 			next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1161 
1162 			sf->error = btrfsic_create_link_to_next_block(
1163 					state,
1164 					sf->block,
1165 					sf->block_ctx,
1166 					next_bytenr,
1167 					sf->limit_nesting,
1168 					&sf->next_block_ctx,
1169 					&sf->next_block,
1170 					force_iodone_flag,
1171 					&sf->num_copies,
1172 					&sf->mirror_num,
1173 					&key_ptr.key,
1174 					btrfs_stack_key_generation(&key_ptr));
1175 			if (sf->error)
1176 				goto one_stack_frame_backwards;
1177 
1178 			if (NULL != sf->next_block) {
1179 				struct btrfs_header *const next_hdr =
1180 				    (struct btrfs_header *)
1181 				    sf->next_block_ctx.datav[0];
1182 
1183 				next_stack = btrfsic_stack_frame_alloc();
1184 				if (NULL == next_stack)
1185 					goto one_stack_frame_backwards;
1186 
1187 				next_stack->i = -1;
1188 				next_stack->block = sf->next_block;
1189 				next_stack->block_ctx = &sf->next_block_ctx;
1190 				next_stack->next_block = NULL;
1191 				next_stack->hdr = next_hdr;
1192 				next_stack->limit_nesting =
1193 				    sf->limit_nesting - 1;
1194 				next_stack->prev = sf;
1195 				sf = next_stack;
1196 				goto continue_with_new_stack_frame;
1197 			}
1198 
1199 			goto continue_with_current_node_stack_frame;
1200 		}
1201 	}
1202 
1203 one_stack_frame_backwards:
1204 	if (NULL != sf->prev) {
1205 		struct btrfsic_stack_frame *const prev = sf->prev;
1206 
1207 		/* the one for the initial block is freed in the caller */
1208 		btrfsic_release_block_ctx(sf->block_ctx);
1209 
1210 		if (sf->error) {
1211 			prev->error = sf->error;
1212 			btrfsic_stack_frame_free(sf);
1213 			sf = prev;
1214 			goto one_stack_frame_backwards;
1215 		}
1216 
1217 		btrfsic_stack_frame_free(sf);
1218 		sf = prev;
1219 		goto continue_with_new_stack_frame;
1220 	} else {
1221 		BUG_ON(&initial_stack_frame != sf);
1222 	}
1223 
1224 	return sf->error;
1225 }
1226 
1227 static void btrfsic_read_from_block_data(
1228 	struct btrfsic_block_data_ctx *block_ctx,
1229 	void *dstv, u32 offset, size_t len)
1230 {
1231 	size_t cur;
1232 	size_t offset_in_page;
1233 	char *kaddr;
1234 	char *dst = (char *)dstv;
1235 	size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1236 	unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1237 
1238 	WARN_ON(offset + len > block_ctx->len);
1239 	offset_in_page = (start_offset + offset) & (PAGE_CACHE_SIZE - 1);
1240 
1241 	while (len > 0) {
1242 		cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1243 		BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
1244 			    PAGE_CACHE_SHIFT);
1245 		kaddr = block_ctx->datav[i];
1246 		memcpy(dst, kaddr + offset_in_page, cur);
1247 
1248 		dst += cur;
1249 		len -= cur;
1250 		offset_in_page = 0;
1251 		i++;
1252 	}
1253 }
1254 
1255 static int btrfsic_create_link_to_next_block(
1256 		struct btrfsic_state *state,
1257 		struct btrfsic_block *block,
1258 		struct btrfsic_block_data_ctx *block_ctx,
1259 		u64 next_bytenr,
1260 		int limit_nesting,
1261 		struct btrfsic_block_data_ctx *next_block_ctx,
1262 		struct btrfsic_block **next_blockp,
1263 		int force_iodone_flag,
1264 		int *num_copiesp, int *mirror_nump,
1265 		struct btrfs_disk_key *disk_key,
1266 		u64 parent_generation)
1267 {
1268 	struct btrfsic_block *next_block = NULL;
1269 	int ret;
1270 	struct btrfsic_block_link *l;
1271 	int did_alloc_block_link;
1272 	int block_was_created;
1273 
1274 	*next_blockp = NULL;
1275 	if (0 == *num_copiesp) {
1276 		*num_copiesp =
1277 		    btrfs_num_copies(state->root->fs_info,
1278 				     next_bytenr, state->metablock_size);
1279 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1280 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1281 			       next_bytenr, *num_copiesp);
1282 		*mirror_nump = 1;
1283 	}
1284 
1285 	if (*mirror_nump > *num_copiesp)
1286 		return 0;
1287 
1288 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1289 		printk(KERN_INFO
1290 		       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1291 		       *mirror_nump);
1292 	ret = btrfsic_map_block(state, next_bytenr,
1293 				state->metablock_size,
1294 				next_block_ctx, *mirror_nump);
1295 	if (ret) {
1296 		printk(KERN_INFO
1297 		       "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1298 		       next_bytenr, *mirror_nump);
1299 		btrfsic_release_block_ctx(next_block_ctx);
1300 		*next_blockp = NULL;
1301 		return -1;
1302 	}
1303 
1304 	next_block = btrfsic_block_lookup_or_add(state,
1305 						 next_block_ctx, "referenced ",
1306 						 1, force_iodone_flag,
1307 						 !force_iodone_flag,
1308 						 *mirror_nump,
1309 						 &block_was_created);
1310 	if (NULL == next_block) {
1311 		btrfsic_release_block_ctx(next_block_ctx);
1312 		*next_blockp = NULL;
1313 		return -1;
1314 	}
1315 	if (block_was_created) {
1316 		l = NULL;
1317 		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1318 	} else {
1319 		if (next_block->logical_bytenr != next_bytenr &&
1320 		    !(!next_block->is_metadata &&
1321 		      0 == next_block->logical_bytenr)) {
1322 			printk(KERN_INFO
1323 			       "Referenced block @%llu (%s/%llu/%d)"
1324 			       " found in hash table, %c,"
1325 			       " bytenr mismatch (!= stored %llu).\n",
1326 			       next_bytenr, next_block_ctx->dev->name,
1327 			       next_block_ctx->dev_bytenr, *mirror_nump,
1328 			       btrfsic_get_block_type(state, next_block),
1329 			       next_block->logical_bytenr);
1330 		} else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1331 			printk(KERN_INFO
1332 			       "Referenced block @%llu (%s/%llu/%d)"
1333 			       " found in hash table, %c.\n",
1334 			       next_bytenr, next_block_ctx->dev->name,
1335 			       next_block_ctx->dev_bytenr, *mirror_nump,
1336 			       btrfsic_get_block_type(state, next_block));
1337 		next_block->logical_bytenr = next_bytenr;
1338 
1339 		next_block->mirror_num = *mirror_nump;
1340 		l = btrfsic_block_link_hashtable_lookup(
1341 				next_block_ctx->dev->bdev,
1342 				next_block_ctx->dev_bytenr,
1343 				block_ctx->dev->bdev,
1344 				block_ctx->dev_bytenr,
1345 				&state->block_link_hashtable);
1346 	}
1347 
1348 	next_block->disk_key = *disk_key;
1349 	if (NULL == l) {
1350 		l = btrfsic_block_link_alloc();
1351 		if (NULL == l) {
1352 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1353 			btrfsic_release_block_ctx(next_block_ctx);
1354 			*next_blockp = NULL;
1355 			return -1;
1356 		}
1357 
1358 		did_alloc_block_link = 1;
1359 		l->block_ref_to = next_block;
1360 		l->block_ref_from = block;
1361 		l->ref_cnt = 1;
1362 		l->parent_generation = parent_generation;
1363 
1364 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1365 			btrfsic_print_add_link(state, l);
1366 
1367 		list_add(&l->node_ref_to, &block->ref_to_list);
1368 		list_add(&l->node_ref_from, &next_block->ref_from_list);
1369 
1370 		btrfsic_block_link_hashtable_add(l,
1371 						 &state->block_link_hashtable);
1372 	} else {
1373 		did_alloc_block_link = 0;
1374 		if (0 == limit_nesting) {
1375 			l->ref_cnt++;
1376 			l->parent_generation = parent_generation;
1377 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1378 				btrfsic_print_add_link(state, l);
1379 		}
1380 	}
1381 
1382 	if (limit_nesting > 0 && did_alloc_block_link) {
1383 		ret = btrfsic_read_block(state, next_block_ctx);
1384 		if (ret < (int)next_block_ctx->len) {
1385 			printk(KERN_INFO
1386 			       "btrfsic: read block @logical %llu failed!\n",
1387 			       next_bytenr);
1388 			btrfsic_release_block_ctx(next_block_ctx);
1389 			*next_blockp = NULL;
1390 			return -1;
1391 		}
1392 
1393 		*next_blockp = next_block;
1394 	} else {
1395 		*next_blockp = NULL;
1396 	}
1397 	(*mirror_nump)++;
1398 
1399 	return 0;
1400 }
1401 
1402 static int btrfsic_handle_extent_data(
1403 		struct btrfsic_state *state,
1404 		struct btrfsic_block *block,
1405 		struct btrfsic_block_data_ctx *block_ctx,
1406 		u32 item_offset, int force_iodone_flag)
1407 {
1408 	int ret;
1409 	struct btrfs_file_extent_item file_extent_item;
1410 	u64 file_extent_item_offset;
1411 	u64 next_bytenr;
1412 	u64 num_bytes;
1413 	u64 generation;
1414 	struct btrfsic_block_link *l;
1415 
1416 	file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1417 				  item_offset;
1418 	if (file_extent_item_offset +
1419 	    offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1420 	    block_ctx->len) {
1421 		printk(KERN_INFO
1422 		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1423 		       block_ctx->start, block_ctx->dev->name);
1424 		return -1;
1425 	}
1426 
1427 	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1428 		file_extent_item_offset,
1429 		offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1430 	if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1431 	    btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1432 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1433 			printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1434 			       file_extent_item.type,
1435 			       btrfs_stack_file_extent_disk_bytenr(
1436 			       &file_extent_item));
1437 		return 0;
1438 	}
1439 
1440 	if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1441 	    block_ctx->len) {
1442 		printk(KERN_INFO
1443 		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1444 		       block_ctx->start, block_ctx->dev->name);
1445 		return -1;
1446 	}
1447 	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1448 				     file_extent_item_offset,
1449 				     sizeof(struct btrfs_file_extent_item));
1450 	next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item) +
1451 		      btrfs_stack_file_extent_offset(&file_extent_item);
1452 	generation = btrfs_stack_file_extent_generation(&file_extent_item);
1453 	num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1454 	generation = btrfs_stack_file_extent_generation(&file_extent_item);
1455 
1456 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1457 		printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1458 		       " offset = %llu, num_bytes = %llu\n",
1459 		       file_extent_item.type,
1460 		       btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1461 		       btrfs_stack_file_extent_offset(&file_extent_item),
1462 		       num_bytes);
1463 	while (num_bytes > 0) {
1464 		u32 chunk_len;
1465 		int num_copies;
1466 		int mirror_num;
1467 
1468 		if (num_bytes > state->datablock_size)
1469 			chunk_len = state->datablock_size;
1470 		else
1471 			chunk_len = num_bytes;
1472 
1473 		num_copies =
1474 		    btrfs_num_copies(state->root->fs_info,
1475 				     next_bytenr, state->datablock_size);
1476 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1477 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1478 			       next_bytenr, num_copies);
1479 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1480 			struct btrfsic_block_data_ctx next_block_ctx;
1481 			struct btrfsic_block *next_block;
1482 			int block_was_created;
1483 
1484 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1485 				printk(KERN_INFO "btrfsic_handle_extent_data("
1486 				       "mirror_num=%d)\n", mirror_num);
1487 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1488 				printk(KERN_INFO
1489 				       "\tdisk_bytenr = %llu, num_bytes %u\n",
1490 				       next_bytenr, chunk_len);
1491 			ret = btrfsic_map_block(state, next_bytenr,
1492 						chunk_len, &next_block_ctx,
1493 						mirror_num);
1494 			if (ret) {
1495 				printk(KERN_INFO
1496 				       "btrfsic: btrfsic_map_block(@%llu,"
1497 				       " mirror=%d) failed!\n",
1498 				       next_bytenr, mirror_num);
1499 				return -1;
1500 			}
1501 
1502 			next_block = btrfsic_block_lookup_or_add(
1503 					state,
1504 					&next_block_ctx,
1505 					"referenced ",
1506 					0,
1507 					force_iodone_flag,
1508 					!force_iodone_flag,
1509 					mirror_num,
1510 					&block_was_created);
1511 			if (NULL == next_block) {
1512 				printk(KERN_INFO
1513 				       "btrfsic: error, kmalloc failed!\n");
1514 				btrfsic_release_block_ctx(&next_block_ctx);
1515 				return -1;
1516 			}
1517 			if (!block_was_created) {
1518 				if (next_block->logical_bytenr != next_bytenr &&
1519 				    !(!next_block->is_metadata &&
1520 				      0 == next_block->logical_bytenr)) {
1521 					printk(KERN_INFO
1522 					       "Referenced block"
1523 					       " @%llu (%s/%llu/%d)"
1524 					       " found in hash table, D,"
1525 					       " bytenr mismatch"
1526 					       " (!= stored %llu).\n",
1527 					       next_bytenr,
1528 					       next_block_ctx.dev->name,
1529 					       next_block_ctx.dev_bytenr,
1530 					       mirror_num,
1531 					       next_block->logical_bytenr);
1532 				}
1533 				next_block->logical_bytenr = next_bytenr;
1534 				next_block->mirror_num = mirror_num;
1535 			}
1536 
1537 			l = btrfsic_block_link_lookup_or_add(state,
1538 							     &next_block_ctx,
1539 							     next_block, block,
1540 							     generation);
1541 			btrfsic_release_block_ctx(&next_block_ctx);
1542 			if (NULL == l)
1543 				return -1;
1544 		}
1545 
1546 		next_bytenr += chunk_len;
1547 		num_bytes -= chunk_len;
1548 	}
1549 
1550 	return 0;
1551 }
1552 
1553 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1554 			     struct btrfsic_block_data_ctx *block_ctx_out,
1555 			     int mirror_num)
1556 {
1557 	int ret;
1558 	u64 length;
1559 	struct btrfs_bio *multi = NULL;
1560 	struct btrfs_device *device;
1561 
1562 	length = len;
1563 	ret = btrfs_map_block(state->root->fs_info, READ,
1564 			      bytenr, &length, &multi, mirror_num);
1565 
1566 	if (ret) {
1567 		block_ctx_out->start = 0;
1568 		block_ctx_out->dev_bytenr = 0;
1569 		block_ctx_out->len = 0;
1570 		block_ctx_out->dev = NULL;
1571 		block_ctx_out->datav = NULL;
1572 		block_ctx_out->pagev = NULL;
1573 		block_ctx_out->mem_to_free = NULL;
1574 
1575 		return ret;
1576 	}
1577 
1578 	device = multi->stripes[0].dev;
1579 	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1580 	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1581 	block_ctx_out->start = bytenr;
1582 	block_ctx_out->len = len;
1583 	block_ctx_out->datav = NULL;
1584 	block_ctx_out->pagev = NULL;
1585 	block_ctx_out->mem_to_free = NULL;
1586 
1587 	kfree(multi);
1588 	if (NULL == block_ctx_out->dev) {
1589 		ret = -ENXIO;
1590 		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1591 	}
1592 
1593 	return ret;
1594 }
1595 
1596 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1597 				  u32 len, struct block_device *bdev,
1598 				  struct btrfsic_block_data_ctx *block_ctx_out)
1599 {
1600 	block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1601 	block_ctx_out->dev_bytenr = bytenr;
1602 	block_ctx_out->start = bytenr;
1603 	block_ctx_out->len = len;
1604 	block_ctx_out->datav = NULL;
1605 	block_ctx_out->pagev = NULL;
1606 	block_ctx_out->mem_to_free = NULL;
1607 	if (NULL != block_ctx_out->dev) {
1608 		return 0;
1609 	} else {
1610 		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1611 		return -ENXIO;
1612 	}
1613 }
1614 
1615 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1616 {
1617 	if (block_ctx->mem_to_free) {
1618 		unsigned int num_pages;
1619 
1620 		BUG_ON(!block_ctx->datav);
1621 		BUG_ON(!block_ctx->pagev);
1622 		num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1623 			    PAGE_CACHE_SHIFT;
1624 		while (num_pages > 0) {
1625 			num_pages--;
1626 			if (block_ctx->datav[num_pages]) {
1627 				kunmap(block_ctx->pagev[num_pages]);
1628 				block_ctx->datav[num_pages] = NULL;
1629 			}
1630 			if (block_ctx->pagev[num_pages]) {
1631 				__free_page(block_ctx->pagev[num_pages]);
1632 				block_ctx->pagev[num_pages] = NULL;
1633 			}
1634 		}
1635 
1636 		kfree(block_ctx->mem_to_free);
1637 		block_ctx->mem_to_free = NULL;
1638 		block_ctx->pagev = NULL;
1639 		block_ctx->datav = NULL;
1640 	}
1641 }
1642 
1643 static int btrfsic_read_block(struct btrfsic_state *state,
1644 			      struct btrfsic_block_data_ctx *block_ctx)
1645 {
1646 	unsigned int num_pages;
1647 	unsigned int i;
1648 	u64 dev_bytenr;
1649 	int ret;
1650 
1651 	BUG_ON(block_ctx->datav);
1652 	BUG_ON(block_ctx->pagev);
1653 	BUG_ON(block_ctx->mem_to_free);
1654 	if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1655 		printk(KERN_INFO
1656 		       "btrfsic: read_block() with unaligned bytenr %llu\n",
1657 		       block_ctx->dev_bytenr);
1658 		return -1;
1659 	}
1660 
1661 	num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1662 		    PAGE_CACHE_SHIFT;
1663 	block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1664 					  sizeof(*block_ctx->pagev)) *
1665 					 num_pages, GFP_NOFS);
1666 	if (!block_ctx->mem_to_free)
1667 		return -1;
1668 	block_ctx->datav = block_ctx->mem_to_free;
1669 	block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1670 	for (i = 0; i < num_pages; i++) {
1671 		block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1672 		if (!block_ctx->pagev[i])
1673 			return -1;
1674 	}
1675 
1676 	dev_bytenr = block_ctx->dev_bytenr;
1677 	for (i = 0; i < num_pages;) {
1678 		struct bio *bio;
1679 		unsigned int j;
1680 		DECLARE_COMPLETION_ONSTACK(complete);
1681 
1682 		bio = btrfs_io_bio_alloc(GFP_NOFS, num_pages - i);
1683 		if (!bio) {
1684 			printk(KERN_INFO
1685 			       "btrfsic: bio_alloc() for %u pages failed!\n",
1686 			       num_pages - i);
1687 			return -1;
1688 		}
1689 		bio->bi_bdev = block_ctx->dev->bdev;
1690 		bio->bi_sector = dev_bytenr >> 9;
1691 		bio->bi_end_io = btrfsic_complete_bio_end_io;
1692 		bio->bi_private = &complete;
1693 
1694 		for (j = i; j < num_pages; j++) {
1695 			ret = bio_add_page(bio, block_ctx->pagev[j],
1696 					   PAGE_CACHE_SIZE, 0);
1697 			if (PAGE_CACHE_SIZE != ret)
1698 				break;
1699 		}
1700 		if (j == i) {
1701 			printk(KERN_INFO
1702 			       "btrfsic: error, failed to add a single page!\n");
1703 			return -1;
1704 		}
1705 		submit_bio(READ, bio);
1706 
1707 		/* this will also unplug the queue */
1708 		wait_for_completion(&complete);
1709 
1710 		if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
1711 			printk(KERN_INFO
1712 			       "btrfsic: read error at logical %llu dev %s!\n",
1713 			       block_ctx->start, block_ctx->dev->name);
1714 			bio_put(bio);
1715 			return -1;
1716 		}
1717 		bio_put(bio);
1718 		dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1719 		i = j;
1720 	}
1721 	for (i = 0; i < num_pages; i++) {
1722 		block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1723 		if (!block_ctx->datav[i]) {
1724 			printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1725 			       block_ctx->dev->name);
1726 			return -1;
1727 		}
1728 	}
1729 
1730 	return block_ctx->len;
1731 }
1732 
1733 static void btrfsic_complete_bio_end_io(struct bio *bio, int err)
1734 {
1735 	complete((struct completion *)bio->bi_private);
1736 }
1737 
1738 static void btrfsic_dump_database(struct btrfsic_state *state)
1739 {
1740 	struct list_head *elem_all;
1741 
1742 	BUG_ON(NULL == state);
1743 
1744 	printk(KERN_INFO "all_blocks_list:\n");
1745 	list_for_each(elem_all, &state->all_blocks_list) {
1746 		const struct btrfsic_block *const b_all =
1747 		    list_entry(elem_all, struct btrfsic_block,
1748 			       all_blocks_node);
1749 		struct list_head *elem_ref_to;
1750 		struct list_head *elem_ref_from;
1751 
1752 		printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1753 		       btrfsic_get_block_type(state, b_all),
1754 		       b_all->logical_bytenr, b_all->dev_state->name,
1755 		       b_all->dev_bytenr, b_all->mirror_num);
1756 
1757 		list_for_each(elem_ref_to, &b_all->ref_to_list) {
1758 			const struct btrfsic_block_link *const l =
1759 			    list_entry(elem_ref_to,
1760 				       struct btrfsic_block_link,
1761 				       node_ref_to);
1762 
1763 			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1764 			       " refers %u* to"
1765 			       " %c @%llu (%s/%llu/%d)\n",
1766 			       btrfsic_get_block_type(state, b_all),
1767 			       b_all->logical_bytenr, b_all->dev_state->name,
1768 			       b_all->dev_bytenr, b_all->mirror_num,
1769 			       l->ref_cnt,
1770 			       btrfsic_get_block_type(state, l->block_ref_to),
1771 			       l->block_ref_to->logical_bytenr,
1772 			       l->block_ref_to->dev_state->name,
1773 			       l->block_ref_to->dev_bytenr,
1774 			       l->block_ref_to->mirror_num);
1775 		}
1776 
1777 		list_for_each(elem_ref_from, &b_all->ref_from_list) {
1778 			const struct btrfsic_block_link *const l =
1779 			    list_entry(elem_ref_from,
1780 				       struct btrfsic_block_link,
1781 				       node_ref_from);
1782 
1783 			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1784 			       " is ref %u* from"
1785 			       " %c @%llu (%s/%llu/%d)\n",
1786 			       btrfsic_get_block_type(state, b_all),
1787 			       b_all->logical_bytenr, b_all->dev_state->name,
1788 			       b_all->dev_bytenr, b_all->mirror_num,
1789 			       l->ref_cnt,
1790 			       btrfsic_get_block_type(state, l->block_ref_from),
1791 			       l->block_ref_from->logical_bytenr,
1792 			       l->block_ref_from->dev_state->name,
1793 			       l->block_ref_from->dev_bytenr,
1794 			       l->block_ref_from->mirror_num);
1795 		}
1796 
1797 		printk(KERN_INFO "\n");
1798 	}
1799 }
1800 
1801 /*
1802  * Test whether the disk block contains a tree block (leaf or node)
1803  * (note that this test fails for the super block)
1804  */
1805 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1806 				     char **datav, unsigned int num_pages)
1807 {
1808 	struct btrfs_header *h;
1809 	u8 csum[BTRFS_CSUM_SIZE];
1810 	u32 crc = ~(u32)0;
1811 	unsigned int i;
1812 
1813 	if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1814 		return 1; /* not metadata */
1815 	num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1816 	h = (struct btrfs_header *)datav[0];
1817 
1818 	if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1819 		return 1;
1820 
1821 	for (i = 0; i < num_pages; i++) {
1822 		u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1823 		size_t sublen = i ? PAGE_CACHE_SIZE :
1824 				    (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1825 
1826 		crc = crc32c(crc, data, sublen);
1827 	}
1828 	btrfs_csum_final(crc, csum);
1829 	if (memcmp(csum, h->csum, state->csum_size))
1830 		return 1;
1831 
1832 	return 0; /* is metadata */
1833 }
1834 
1835 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1836 					  u64 dev_bytenr, char **mapped_datav,
1837 					  unsigned int num_pages,
1838 					  struct bio *bio, int *bio_is_patched,
1839 					  struct buffer_head *bh,
1840 					  int submit_bio_bh_rw)
1841 {
1842 	int is_metadata;
1843 	struct btrfsic_block *block;
1844 	struct btrfsic_block_data_ctx block_ctx;
1845 	int ret;
1846 	struct btrfsic_state *state = dev_state->state;
1847 	struct block_device *bdev = dev_state->bdev;
1848 	unsigned int processed_len;
1849 
1850 	if (NULL != bio_is_patched)
1851 		*bio_is_patched = 0;
1852 
1853 again:
1854 	if (num_pages == 0)
1855 		return;
1856 
1857 	processed_len = 0;
1858 	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1859 						      num_pages));
1860 
1861 	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1862 					       &state->block_hashtable);
1863 	if (NULL != block) {
1864 		u64 bytenr = 0;
1865 		struct list_head *elem_ref_to;
1866 		struct list_head *tmp_ref_to;
1867 
1868 		if (block->is_superblock) {
1869 			bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1870 						    mapped_datav[0]);
1871 			if (num_pages * PAGE_CACHE_SIZE <
1872 			    BTRFS_SUPER_INFO_SIZE) {
1873 				printk(KERN_INFO
1874 				       "btrfsic: cannot work with too short bios!\n");
1875 				return;
1876 			}
1877 			is_metadata = 1;
1878 			BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1879 			processed_len = BTRFS_SUPER_INFO_SIZE;
1880 			if (state->print_mask &
1881 			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1882 				printk(KERN_INFO
1883 				       "[before new superblock is written]:\n");
1884 				btrfsic_dump_tree_sub(state, block, 0);
1885 			}
1886 		}
1887 		if (is_metadata) {
1888 			if (!block->is_superblock) {
1889 				if (num_pages * PAGE_CACHE_SIZE <
1890 				    state->metablock_size) {
1891 					printk(KERN_INFO
1892 					       "btrfsic: cannot work with too short bios!\n");
1893 					return;
1894 				}
1895 				processed_len = state->metablock_size;
1896 				bytenr = btrfs_stack_header_bytenr(
1897 						(struct btrfs_header *)
1898 						mapped_datav[0]);
1899 				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1900 							       dev_state,
1901 							       dev_bytenr);
1902 			}
1903 			if (block->logical_bytenr != bytenr) {
1904 				printk(KERN_INFO
1905 				       "Written block @%llu (%s/%llu/%d)"
1906 				       " found in hash table, %c,"
1907 				       " bytenr mismatch"
1908 				       " (!= stored %llu).\n",
1909 				       bytenr, dev_state->name, dev_bytenr,
1910 				       block->mirror_num,
1911 				       btrfsic_get_block_type(state, block),
1912 				       block->logical_bytenr);
1913 				block->logical_bytenr = bytenr;
1914 			} else if (state->print_mask &
1915 				   BTRFSIC_PRINT_MASK_VERBOSE)
1916 				printk(KERN_INFO
1917 				       "Written block @%llu (%s/%llu/%d)"
1918 				       " found in hash table, %c.\n",
1919 				       bytenr, dev_state->name, dev_bytenr,
1920 				       block->mirror_num,
1921 				       btrfsic_get_block_type(state, block));
1922 		} else {
1923 			if (num_pages * PAGE_CACHE_SIZE <
1924 			    state->datablock_size) {
1925 				printk(KERN_INFO
1926 				       "btrfsic: cannot work with too short bios!\n");
1927 				return;
1928 			}
1929 			processed_len = state->datablock_size;
1930 			bytenr = block->logical_bytenr;
1931 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1932 				printk(KERN_INFO
1933 				       "Written block @%llu (%s/%llu/%d)"
1934 				       " found in hash table, %c.\n",
1935 				       bytenr, dev_state->name, dev_bytenr,
1936 				       block->mirror_num,
1937 				       btrfsic_get_block_type(state, block));
1938 		}
1939 
1940 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1941 			printk(KERN_INFO
1942 			       "ref_to_list: %cE, ref_from_list: %cE\n",
1943 			       list_empty(&block->ref_to_list) ? ' ' : '!',
1944 			       list_empty(&block->ref_from_list) ? ' ' : '!');
1945 		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1946 			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1947 			       " @%llu (%s/%llu/%d), old(gen=%llu,"
1948 			       " objectid=%llu, type=%d, offset=%llu),"
1949 			       " new(gen=%llu),"
1950 			       " which is referenced by most recent superblock"
1951 			       " (superblockgen=%llu)!\n",
1952 			       btrfsic_get_block_type(state, block), bytenr,
1953 			       dev_state->name, dev_bytenr, block->mirror_num,
1954 			       block->generation,
1955 			       btrfs_disk_key_objectid(&block->disk_key),
1956 			       block->disk_key.type,
1957 			       btrfs_disk_key_offset(&block->disk_key),
1958 			       btrfs_stack_header_generation(
1959 				       (struct btrfs_header *) mapped_datav[0]),
1960 			       state->max_superblock_generation);
1961 			btrfsic_dump_tree(state);
1962 		}
1963 
1964 		if (!block->is_iodone && !block->never_written) {
1965 			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1966 			       " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
1967 			       " which is not yet iodone!\n",
1968 			       btrfsic_get_block_type(state, block), bytenr,
1969 			       dev_state->name, dev_bytenr, block->mirror_num,
1970 			       block->generation,
1971 			       btrfs_stack_header_generation(
1972 				       (struct btrfs_header *)
1973 				       mapped_datav[0]));
1974 			/* it would not be safe to go on */
1975 			btrfsic_dump_tree(state);
1976 			goto continue_loop;
1977 		}
1978 
1979 		/*
1980 		 * Clear all references of this block. Do not free
1981 		 * the block itself even if is not referenced anymore
1982 		 * because it still carries valueable information
1983 		 * like whether it was ever written and IO completed.
1984 		 */
1985 		list_for_each_safe(elem_ref_to, tmp_ref_to,
1986 				   &block->ref_to_list) {
1987 			struct btrfsic_block_link *const l =
1988 			    list_entry(elem_ref_to,
1989 				       struct btrfsic_block_link,
1990 				       node_ref_to);
1991 
1992 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1993 				btrfsic_print_rem_link(state, l);
1994 			l->ref_cnt--;
1995 			if (0 == l->ref_cnt) {
1996 				list_del(&l->node_ref_to);
1997 				list_del(&l->node_ref_from);
1998 				btrfsic_block_link_hashtable_remove(l);
1999 				btrfsic_block_link_free(l);
2000 			}
2001 		}
2002 
2003 		if (block->is_superblock)
2004 			ret = btrfsic_map_superblock(state, bytenr,
2005 						     processed_len,
2006 						     bdev, &block_ctx);
2007 		else
2008 			ret = btrfsic_map_block(state, bytenr, processed_len,
2009 						&block_ctx, 0);
2010 		if (ret) {
2011 			printk(KERN_INFO
2012 			       "btrfsic: btrfsic_map_block(root @%llu)"
2013 			       " failed!\n", bytenr);
2014 			goto continue_loop;
2015 		}
2016 		block_ctx.datav = mapped_datav;
2017 		/* the following is required in case of writes to mirrors,
2018 		 * use the same that was used for the lookup */
2019 		block_ctx.dev = dev_state;
2020 		block_ctx.dev_bytenr = dev_bytenr;
2021 
2022 		if (is_metadata || state->include_extent_data) {
2023 			block->never_written = 0;
2024 			block->iodone_w_error = 0;
2025 			if (NULL != bio) {
2026 				block->is_iodone = 0;
2027 				BUG_ON(NULL == bio_is_patched);
2028 				if (!*bio_is_patched) {
2029 					block->orig_bio_bh_private =
2030 					    bio->bi_private;
2031 					block->orig_bio_bh_end_io.bio =
2032 					    bio->bi_end_io;
2033 					block->next_in_same_bio = NULL;
2034 					bio->bi_private = block;
2035 					bio->bi_end_io = btrfsic_bio_end_io;
2036 					*bio_is_patched = 1;
2037 				} else {
2038 					struct btrfsic_block *chained_block =
2039 					    (struct btrfsic_block *)
2040 					    bio->bi_private;
2041 
2042 					BUG_ON(NULL == chained_block);
2043 					block->orig_bio_bh_private =
2044 					    chained_block->orig_bio_bh_private;
2045 					block->orig_bio_bh_end_io.bio =
2046 					    chained_block->orig_bio_bh_end_io.
2047 					    bio;
2048 					block->next_in_same_bio = chained_block;
2049 					bio->bi_private = block;
2050 				}
2051 			} else if (NULL != bh) {
2052 				block->is_iodone = 0;
2053 				block->orig_bio_bh_private = bh->b_private;
2054 				block->orig_bio_bh_end_io.bh = bh->b_end_io;
2055 				block->next_in_same_bio = NULL;
2056 				bh->b_private = block;
2057 				bh->b_end_io = btrfsic_bh_end_io;
2058 			} else {
2059 				block->is_iodone = 1;
2060 				block->orig_bio_bh_private = NULL;
2061 				block->orig_bio_bh_end_io.bio = NULL;
2062 				block->next_in_same_bio = NULL;
2063 			}
2064 		}
2065 
2066 		block->flush_gen = dev_state->last_flush_gen + 1;
2067 		block->submit_bio_bh_rw = submit_bio_bh_rw;
2068 		if (is_metadata) {
2069 			block->logical_bytenr = bytenr;
2070 			block->is_metadata = 1;
2071 			if (block->is_superblock) {
2072 				BUG_ON(PAGE_CACHE_SIZE !=
2073 				       BTRFS_SUPER_INFO_SIZE);
2074 				ret = btrfsic_process_written_superblock(
2075 						state,
2076 						block,
2077 						(struct btrfs_super_block *)
2078 						mapped_datav[0]);
2079 				if (state->print_mask &
2080 				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2081 					printk(KERN_INFO
2082 					"[after new superblock is written]:\n");
2083 					btrfsic_dump_tree_sub(state, block, 0);
2084 				}
2085 			} else {
2086 				block->mirror_num = 0;	/* unknown */
2087 				ret = btrfsic_process_metablock(
2088 						state,
2089 						block,
2090 						&block_ctx,
2091 						0, 0);
2092 			}
2093 			if (ret)
2094 				printk(KERN_INFO
2095 				       "btrfsic: btrfsic_process_metablock"
2096 				       "(root @%llu) failed!\n",
2097 				       dev_bytenr);
2098 		} else {
2099 			block->is_metadata = 0;
2100 			block->mirror_num = 0;	/* unknown */
2101 			block->generation = BTRFSIC_GENERATION_UNKNOWN;
2102 			if (!state->include_extent_data
2103 			    && list_empty(&block->ref_from_list)) {
2104 				/*
2105 				 * disk block is overwritten with extent
2106 				 * data (not meta data) and we are configured
2107 				 * to not include extent data: take the
2108 				 * chance and free the block's memory
2109 				 */
2110 				btrfsic_block_hashtable_remove(block);
2111 				list_del(&block->all_blocks_node);
2112 				btrfsic_block_free(block);
2113 			}
2114 		}
2115 		btrfsic_release_block_ctx(&block_ctx);
2116 	} else {
2117 		/* block has not been found in hash table */
2118 		u64 bytenr;
2119 
2120 		if (!is_metadata) {
2121 			processed_len = state->datablock_size;
2122 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2123 				printk(KERN_INFO "Written block (%s/%llu/?)"
2124 				       " !found in hash table, D.\n",
2125 				       dev_state->name, dev_bytenr);
2126 			if (!state->include_extent_data) {
2127 				/* ignore that written D block */
2128 				goto continue_loop;
2129 			}
2130 
2131 			/* this is getting ugly for the
2132 			 * include_extent_data case... */
2133 			bytenr = 0;	/* unknown */
2134 			block_ctx.start = bytenr;
2135 			block_ctx.len = processed_len;
2136 			block_ctx.mem_to_free = NULL;
2137 			block_ctx.pagev = NULL;
2138 		} else {
2139 			processed_len = state->metablock_size;
2140 			bytenr = btrfs_stack_header_bytenr(
2141 					(struct btrfs_header *)
2142 					mapped_datav[0]);
2143 			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2144 						       dev_bytenr);
2145 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2146 				printk(KERN_INFO
2147 				       "Written block @%llu (%s/%llu/?)"
2148 				       " !found in hash table, M.\n",
2149 				       bytenr, dev_state->name, dev_bytenr);
2150 
2151 			ret = btrfsic_map_block(state, bytenr, processed_len,
2152 						&block_ctx, 0);
2153 			if (ret) {
2154 				printk(KERN_INFO
2155 				       "btrfsic: btrfsic_map_block(root @%llu)"
2156 				       " failed!\n",
2157 				       dev_bytenr);
2158 				goto continue_loop;
2159 			}
2160 		}
2161 		block_ctx.datav = mapped_datav;
2162 		/* the following is required in case of writes to mirrors,
2163 		 * use the same that was used for the lookup */
2164 		block_ctx.dev = dev_state;
2165 		block_ctx.dev_bytenr = dev_bytenr;
2166 
2167 		block = btrfsic_block_alloc();
2168 		if (NULL == block) {
2169 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2170 			btrfsic_release_block_ctx(&block_ctx);
2171 			goto continue_loop;
2172 		}
2173 		block->dev_state = dev_state;
2174 		block->dev_bytenr = dev_bytenr;
2175 		block->logical_bytenr = bytenr;
2176 		block->is_metadata = is_metadata;
2177 		block->never_written = 0;
2178 		block->iodone_w_error = 0;
2179 		block->mirror_num = 0;	/* unknown */
2180 		block->flush_gen = dev_state->last_flush_gen + 1;
2181 		block->submit_bio_bh_rw = submit_bio_bh_rw;
2182 		if (NULL != bio) {
2183 			block->is_iodone = 0;
2184 			BUG_ON(NULL == bio_is_patched);
2185 			if (!*bio_is_patched) {
2186 				block->orig_bio_bh_private = bio->bi_private;
2187 				block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2188 				block->next_in_same_bio = NULL;
2189 				bio->bi_private = block;
2190 				bio->bi_end_io = btrfsic_bio_end_io;
2191 				*bio_is_patched = 1;
2192 			} else {
2193 				struct btrfsic_block *chained_block =
2194 				    (struct btrfsic_block *)
2195 				    bio->bi_private;
2196 
2197 				BUG_ON(NULL == chained_block);
2198 				block->orig_bio_bh_private =
2199 				    chained_block->orig_bio_bh_private;
2200 				block->orig_bio_bh_end_io.bio =
2201 				    chained_block->orig_bio_bh_end_io.bio;
2202 				block->next_in_same_bio = chained_block;
2203 				bio->bi_private = block;
2204 			}
2205 		} else if (NULL != bh) {
2206 			block->is_iodone = 0;
2207 			block->orig_bio_bh_private = bh->b_private;
2208 			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2209 			block->next_in_same_bio = NULL;
2210 			bh->b_private = block;
2211 			bh->b_end_io = btrfsic_bh_end_io;
2212 		} else {
2213 			block->is_iodone = 1;
2214 			block->orig_bio_bh_private = NULL;
2215 			block->orig_bio_bh_end_io.bio = NULL;
2216 			block->next_in_same_bio = NULL;
2217 		}
2218 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2219 			printk(KERN_INFO
2220 			       "New written %c-block @%llu (%s/%llu/%d)\n",
2221 			       is_metadata ? 'M' : 'D',
2222 			       block->logical_bytenr, block->dev_state->name,
2223 			       block->dev_bytenr, block->mirror_num);
2224 		list_add(&block->all_blocks_node, &state->all_blocks_list);
2225 		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2226 
2227 		if (is_metadata) {
2228 			ret = btrfsic_process_metablock(state, block,
2229 							&block_ctx, 0, 0);
2230 			if (ret)
2231 				printk(KERN_INFO
2232 				       "btrfsic: process_metablock(root @%llu)"
2233 				       " failed!\n",
2234 				       dev_bytenr);
2235 		}
2236 		btrfsic_release_block_ctx(&block_ctx);
2237 	}
2238 
2239 continue_loop:
2240 	BUG_ON(!processed_len);
2241 	dev_bytenr += processed_len;
2242 	mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2243 	num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2244 	goto again;
2245 }
2246 
2247 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2248 {
2249 	struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2250 	int iodone_w_error;
2251 
2252 	/* mutex is not held! This is not save if IO is not yet completed
2253 	 * on umount */
2254 	iodone_w_error = 0;
2255 	if (bio_error_status)
2256 		iodone_w_error = 1;
2257 
2258 	BUG_ON(NULL == block);
2259 	bp->bi_private = block->orig_bio_bh_private;
2260 	bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2261 
2262 	do {
2263 		struct btrfsic_block *next_block;
2264 		struct btrfsic_dev_state *const dev_state = block->dev_state;
2265 
2266 		if ((dev_state->state->print_mask &
2267 		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2268 			printk(KERN_INFO
2269 			       "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2270 			       bio_error_status,
2271 			       btrfsic_get_block_type(dev_state->state, block),
2272 			       block->logical_bytenr, dev_state->name,
2273 			       block->dev_bytenr, block->mirror_num);
2274 		next_block = block->next_in_same_bio;
2275 		block->iodone_w_error = iodone_w_error;
2276 		if (block->submit_bio_bh_rw & REQ_FLUSH) {
2277 			dev_state->last_flush_gen++;
2278 			if ((dev_state->state->print_mask &
2279 			     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2280 				printk(KERN_INFO
2281 				       "bio_end_io() new %s flush_gen=%llu\n",
2282 				       dev_state->name,
2283 				       dev_state->last_flush_gen);
2284 		}
2285 		if (block->submit_bio_bh_rw & REQ_FUA)
2286 			block->flush_gen = 0; /* FUA completed means block is
2287 					       * on disk */
2288 		block->is_iodone = 1; /* for FLUSH, this releases the block */
2289 		block = next_block;
2290 	} while (NULL != block);
2291 
2292 	bp->bi_end_io(bp, bio_error_status);
2293 }
2294 
2295 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2296 {
2297 	struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2298 	int iodone_w_error = !uptodate;
2299 	struct btrfsic_dev_state *dev_state;
2300 
2301 	BUG_ON(NULL == block);
2302 	dev_state = block->dev_state;
2303 	if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2304 		printk(KERN_INFO
2305 		       "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2306 		       iodone_w_error,
2307 		       btrfsic_get_block_type(dev_state->state, block),
2308 		       block->logical_bytenr, block->dev_state->name,
2309 		       block->dev_bytenr, block->mirror_num);
2310 
2311 	block->iodone_w_error = iodone_w_error;
2312 	if (block->submit_bio_bh_rw & REQ_FLUSH) {
2313 		dev_state->last_flush_gen++;
2314 		if ((dev_state->state->print_mask &
2315 		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2316 			printk(KERN_INFO
2317 			       "bh_end_io() new %s flush_gen=%llu\n",
2318 			       dev_state->name, dev_state->last_flush_gen);
2319 	}
2320 	if (block->submit_bio_bh_rw & REQ_FUA)
2321 		block->flush_gen = 0; /* FUA completed means block is on disk */
2322 
2323 	bh->b_private = block->orig_bio_bh_private;
2324 	bh->b_end_io = block->orig_bio_bh_end_io.bh;
2325 	block->is_iodone = 1; /* for FLUSH, this releases the block */
2326 	bh->b_end_io(bh, uptodate);
2327 }
2328 
2329 static int btrfsic_process_written_superblock(
2330 		struct btrfsic_state *state,
2331 		struct btrfsic_block *const superblock,
2332 		struct btrfs_super_block *const super_hdr)
2333 {
2334 	int pass;
2335 
2336 	superblock->generation = btrfs_super_generation(super_hdr);
2337 	if (!(superblock->generation > state->max_superblock_generation ||
2338 	      0 == state->max_superblock_generation)) {
2339 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2340 			printk(KERN_INFO
2341 			       "btrfsic: superblock @%llu (%s/%llu/%d)"
2342 			       " with old gen %llu <= %llu\n",
2343 			       superblock->logical_bytenr,
2344 			       superblock->dev_state->name,
2345 			       superblock->dev_bytenr, superblock->mirror_num,
2346 			       btrfs_super_generation(super_hdr),
2347 			       state->max_superblock_generation);
2348 	} else {
2349 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2350 			printk(KERN_INFO
2351 			       "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2352 			       " with new gen %llu > %llu\n",
2353 			       superblock->logical_bytenr,
2354 			       superblock->dev_state->name,
2355 			       superblock->dev_bytenr, superblock->mirror_num,
2356 			       btrfs_super_generation(super_hdr),
2357 			       state->max_superblock_generation);
2358 
2359 		state->max_superblock_generation =
2360 		    btrfs_super_generation(super_hdr);
2361 		state->latest_superblock = superblock;
2362 	}
2363 
2364 	for (pass = 0; pass < 3; pass++) {
2365 		int ret;
2366 		u64 next_bytenr;
2367 		struct btrfsic_block *next_block;
2368 		struct btrfsic_block_data_ctx tmp_next_block_ctx;
2369 		struct btrfsic_block_link *l;
2370 		int num_copies;
2371 		int mirror_num;
2372 		const char *additional_string = NULL;
2373 		struct btrfs_disk_key tmp_disk_key = {0};
2374 
2375 		btrfs_set_disk_key_objectid(&tmp_disk_key,
2376 					    BTRFS_ROOT_ITEM_KEY);
2377 		btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2378 
2379 		switch (pass) {
2380 		case 0:
2381 			btrfs_set_disk_key_objectid(&tmp_disk_key,
2382 						    BTRFS_ROOT_TREE_OBJECTID);
2383 			additional_string = "root ";
2384 			next_bytenr = btrfs_super_root(super_hdr);
2385 			if (state->print_mask &
2386 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2387 				printk(KERN_INFO "root@%llu\n", next_bytenr);
2388 			break;
2389 		case 1:
2390 			btrfs_set_disk_key_objectid(&tmp_disk_key,
2391 						    BTRFS_CHUNK_TREE_OBJECTID);
2392 			additional_string = "chunk ";
2393 			next_bytenr = btrfs_super_chunk_root(super_hdr);
2394 			if (state->print_mask &
2395 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2396 				printk(KERN_INFO "chunk@%llu\n", next_bytenr);
2397 			break;
2398 		case 2:
2399 			btrfs_set_disk_key_objectid(&tmp_disk_key,
2400 						    BTRFS_TREE_LOG_OBJECTID);
2401 			additional_string = "log ";
2402 			next_bytenr = btrfs_super_log_root(super_hdr);
2403 			if (0 == next_bytenr)
2404 				continue;
2405 			if (state->print_mask &
2406 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2407 				printk(KERN_INFO "log@%llu\n", next_bytenr);
2408 			break;
2409 		}
2410 
2411 		num_copies =
2412 		    btrfs_num_copies(state->root->fs_info,
2413 				     next_bytenr, BTRFS_SUPER_INFO_SIZE);
2414 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2415 			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2416 			       next_bytenr, num_copies);
2417 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2418 			int was_created;
2419 
2420 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2421 				printk(KERN_INFO
2422 				       "btrfsic_process_written_superblock("
2423 				       "mirror_num=%d)\n", mirror_num);
2424 			ret = btrfsic_map_block(state, next_bytenr,
2425 						BTRFS_SUPER_INFO_SIZE,
2426 						&tmp_next_block_ctx,
2427 						mirror_num);
2428 			if (ret) {
2429 				printk(KERN_INFO
2430 				       "btrfsic: btrfsic_map_block(@%llu,"
2431 				       " mirror=%d) failed!\n",
2432 				       next_bytenr, mirror_num);
2433 				return -1;
2434 			}
2435 
2436 			next_block = btrfsic_block_lookup_or_add(
2437 					state,
2438 					&tmp_next_block_ctx,
2439 					additional_string,
2440 					1, 0, 1,
2441 					mirror_num,
2442 					&was_created);
2443 			if (NULL == next_block) {
2444 				printk(KERN_INFO
2445 				       "btrfsic: error, kmalloc failed!\n");
2446 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
2447 				return -1;
2448 			}
2449 
2450 			next_block->disk_key = tmp_disk_key;
2451 			if (was_created)
2452 				next_block->generation =
2453 				    BTRFSIC_GENERATION_UNKNOWN;
2454 			l = btrfsic_block_link_lookup_or_add(
2455 					state,
2456 					&tmp_next_block_ctx,
2457 					next_block,
2458 					superblock,
2459 					BTRFSIC_GENERATION_UNKNOWN);
2460 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
2461 			if (NULL == l)
2462 				return -1;
2463 		}
2464 	}
2465 
2466 	if (-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)) {
2467 		WARN_ON(1);
2468 		btrfsic_dump_tree(state);
2469 	}
2470 
2471 	return 0;
2472 }
2473 
2474 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2475 					struct btrfsic_block *const block,
2476 					int recursion_level)
2477 {
2478 	struct list_head *elem_ref_to;
2479 	int ret = 0;
2480 
2481 	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2482 		/*
2483 		 * Note that this situation can happen and does not
2484 		 * indicate an error in regular cases. It happens
2485 		 * when disk blocks are freed and later reused.
2486 		 * The check-integrity module is not aware of any
2487 		 * block free operations, it just recognizes block
2488 		 * write operations. Therefore it keeps the linkage
2489 		 * information for a block until a block is
2490 		 * rewritten. This can temporarily cause incorrect
2491 		 * and even circular linkage informations. This
2492 		 * causes no harm unless such blocks are referenced
2493 		 * by the most recent super block.
2494 		 */
2495 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2496 			printk(KERN_INFO
2497 			       "btrfsic: abort cyclic linkage (case 1).\n");
2498 
2499 		return ret;
2500 	}
2501 
2502 	/*
2503 	 * This algorithm is recursive because the amount of used stack
2504 	 * space is very small and the max recursion depth is limited.
2505 	 */
2506 	list_for_each(elem_ref_to, &block->ref_to_list) {
2507 		const struct btrfsic_block_link *const l =
2508 		    list_entry(elem_ref_to, struct btrfsic_block_link,
2509 			       node_ref_to);
2510 
2511 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2512 			printk(KERN_INFO
2513 			       "rl=%d, %c @%llu (%s/%llu/%d)"
2514 			       " %u* refers to %c @%llu (%s/%llu/%d)\n",
2515 			       recursion_level,
2516 			       btrfsic_get_block_type(state, block),
2517 			       block->logical_bytenr, block->dev_state->name,
2518 			       block->dev_bytenr, block->mirror_num,
2519 			       l->ref_cnt,
2520 			       btrfsic_get_block_type(state, l->block_ref_to),
2521 			       l->block_ref_to->logical_bytenr,
2522 			       l->block_ref_to->dev_state->name,
2523 			       l->block_ref_to->dev_bytenr,
2524 			       l->block_ref_to->mirror_num);
2525 		if (l->block_ref_to->never_written) {
2526 			printk(KERN_INFO "btrfs: attempt to write superblock"
2527 			       " which references block %c @%llu (%s/%llu/%d)"
2528 			       " which is never written!\n",
2529 			       btrfsic_get_block_type(state, l->block_ref_to),
2530 			       l->block_ref_to->logical_bytenr,
2531 			       l->block_ref_to->dev_state->name,
2532 			       l->block_ref_to->dev_bytenr,
2533 			       l->block_ref_to->mirror_num);
2534 			ret = -1;
2535 		} else if (!l->block_ref_to->is_iodone) {
2536 			printk(KERN_INFO "btrfs: attempt to write superblock"
2537 			       " which references block %c @%llu (%s/%llu/%d)"
2538 			       " which is not yet iodone!\n",
2539 			       btrfsic_get_block_type(state, l->block_ref_to),
2540 			       l->block_ref_to->logical_bytenr,
2541 			       l->block_ref_to->dev_state->name,
2542 			       l->block_ref_to->dev_bytenr,
2543 			       l->block_ref_to->mirror_num);
2544 			ret = -1;
2545 		} else if (l->block_ref_to->iodone_w_error) {
2546 			printk(KERN_INFO "btrfs: attempt to write superblock"
2547 			       " which references block %c @%llu (%s/%llu/%d)"
2548 			       " which has write error!\n",
2549 			       btrfsic_get_block_type(state, l->block_ref_to),
2550 			       l->block_ref_to->logical_bytenr,
2551 			       l->block_ref_to->dev_state->name,
2552 			       l->block_ref_to->dev_bytenr,
2553 			       l->block_ref_to->mirror_num);
2554 			ret = -1;
2555 		} else if (l->parent_generation !=
2556 			   l->block_ref_to->generation &&
2557 			   BTRFSIC_GENERATION_UNKNOWN !=
2558 			   l->parent_generation &&
2559 			   BTRFSIC_GENERATION_UNKNOWN !=
2560 			   l->block_ref_to->generation) {
2561 			printk(KERN_INFO "btrfs: attempt to write superblock"
2562 			       " which references block %c @%llu (%s/%llu/%d)"
2563 			       " with generation %llu !="
2564 			       " parent generation %llu!\n",
2565 			       btrfsic_get_block_type(state, l->block_ref_to),
2566 			       l->block_ref_to->logical_bytenr,
2567 			       l->block_ref_to->dev_state->name,
2568 			       l->block_ref_to->dev_bytenr,
2569 			       l->block_ref_to->mirror_num,
2570 			       l->block_ref_to->generation,
2571 			       l->parent_generation);
2572 			ret = -1;
2573 		} else if (l->block_ref_to->flush_gen >
2574 			   l->block_ref_to->dev_state->last_flush_gen) {
2575 			printk(KERN_INFO "btrfs: attempt to write superblock"
2576 			       " which references block %c @%llu (%s/%llu/%d)"
2577 			       " which is not flushed out of disk's write cache"
2578 			       " (block flush_gen=%llu,"
2579 			       " dev->flush_gen=%llu)!\n",
2580 			       btrfsic_get_block_type(state, l->block_ref_to),
2581 			       l->block_ref_to->logical_bytenr,
2582 			       l->block_ref_to->dev_state->name,
2583 			       l->block_ref_to->dev_bytenr,
2584 			       l->block_ref_to->mirror_num, block->flush_gen,
2585 			       l->block_ref_to->dev_state->last_flush_gen);
2586 			ret = -1;
2587 		} else if (-1 == btrfsic_check_all_ref_blocks(state,
2588 							      l->block_ref_to,
2589 							      recursion_level +
2590 							      1)) {
2591 			ret = -1;
2592 		}
2593 	}
2594 
2595 	return ret;
2596 }
2597 
2598 static int btrfsic_is_block_ref_by_superblock(
2599 		const struct btrfsic_state *state,
2600 		const struct btrfsic_block *block,
2601 		int recursion_level)
2602 {
2603 	struct list_head *elem_ref_from;
2604 
2605 	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2606 		/* refer to comment at "abort cyclic linkage (case 1)" */
2607 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2608 			printk(KERN_INFO
2609 			       "btrfsic: abort cyclic linkage (case 2).\n");
2610 
2611 		return 0;
2612 	}
2613 
2614 	/*
2615 	 * This algorithm is recursive because the amount of used stack space
2616 	 * is very small and the max recursion depth is limited.
2617 	 */
2618 	list_for_each(elem_ref_from, &block->ref_from_list) {
2619 		const struct btrfsic_block_link *const l =
2620 		    list_entry(elem_ref_from, struct btrfsic_block_link,
2621 			       node_ref_from);
2622 
2623 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2624 			printk(KERN_INFO
2625 			       "rl=%d, %c @%llu (%s/%llu/%d)"
2626 			       " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2627 			       recursion_level,
2628 			       btrfsic_get_block_type(state, block),
2629 			       block->logical_bytenr, block->dev_state->name,
2630 			       block->dev_bytenr, block->mirror_num,
2631 			       l->ref_cnt,
2632 			       btrfsic_get_block_type(state, l->block_ref_from),
2633 			       l->block_ref_from->logical_bytenr,
2634 			       l->block_ref_from->dev_state->name,
2635 			       l->block_ref_from->dev_bytenr,
2636 			       l->block_ref_from->mirror_num);
2637 		if (l->block_ref_from->is_superblock &&
2638 		    state->latest_superblock->dev_bytenr ==
2639 		    l->block_ref_from->dev_bytenr &&
2640 		    state->latest_superblock->dev_state->bdev ==
2641 		    l->block_ref_from->dev_state->bdev)
2642 			return 1;
2643 		else if (btrfsic_is_block_ref_by_superblock(state,
2644 							    l->block_ref_from,
2645 							    recursion_level +
2646 							    1))
2647 			return 1;
2648 	}
2649 
2650 	return 0;
2651 }
2652 
2653 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2654 				   const struct btrfsic_block_link *l)
2655 {
2656 	printk(KERN_INFO
2657 	       "Add %u* link from %c @%llu (%s/%llu/%d)"
2658 	       " to %c @%llu (%s/%llu/%d).\n",
2659 	       l->ref_cnt,
2660 	       btrfsic_get_block_type(state, l->block_ref_from),
2661 	       l->block_ref_from->logical_bytenr,
2662 	       l->block_ref_from->dev_state->name,
2663 	       l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2664 	       btrfsic_get_block_type(state, l->block_ref_to),
2665 	       l->block_ref_to->logical_bytenr,
2666 	       l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2667 	       l->block_ref_to->mirror_num);
2668 }
2669 
2670 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2671 				   const struct btrfsic_block_link *l)
2672 {
2673 	printk(KERN_INFO
2674 	       "Rem %u* link from %c @%llu (%s/%llu/%d)"
2675 	       " to %c @%llu (%s/%llu/%d).\n",
2676 	       l->ref_cnt,
2677 	       btrfsic_get_block_type(state, l->block_ref_from),
2678 	       l->block_ref_from->logical_bytenr,
2679 	       l->block_ref_from->dev_state->name,
2680 	       l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2681 	       btrfsic_get_block_type(state, l->block_ref_to),
2682 	       l->block_ref_to->logical_bytenr,
2683 	       l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2684 	       l->block_ref_to->mirror_num);
2685 }
2686 
2687 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2688 				   const struct btrfsic_block *block)
2689 {
2690 	if (block->is_superblock &&
2691 	    state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2692 	    state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2693 		return 'S';
2694 	else if (block->is_superblock)
2695 		return 's';
2696 	else if (block->is_metadata)
2697 		return 'M';
2698 	else
2699 		return 'D';
2700 }
2701 
2702 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2703 {
2704 	btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2705 }
2706 
2707 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2708 				  const struct btrfsic_block *block,
2709 				  int indent_level)
2710 {
2711 	struct list_head *elem_ref_to;
2712 	int indent_add;
2713 	static char buf[80];
2714 	int cursor_position;
2715 
2716 	/*
2717 	 * Should better fill an on-stack buffer with a complete line and
2718 	 * dump it at once when it is time to print a newline character.
2719 	 */
2720 
2721 	/*
2722 	 * This algorithm is recursive because the amount of used stack space
2723 	 * is very small and the max recursion depth is limited.
2724 	 */
2725 	indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2726 			     btrfsic_get_block_type(state, block),
2727 			     block->logical_bytenr, block->dev_state->name,
2728 			     block->dev_bytenr, block->mirror_num);
2729 	if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2730 		printk("[...]\n");
2731 		return;
2732 	}
2733 	printk(buf);
2734 	indent_level += indent_add;
2735 	if (list_empty(&block->ref_to_list)) {
2736 		printk("\n");
2737 		return;
2738 	}
2739 	if (block->mirror_num > 1 &&
2740 	    !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2741 		printk(" [...]\n");
2742 		return;
2743 	}
2744 
2745 	cursor_position = indent_level;
2746 	list_for_each(elem_ref_to, &block->ref_to_list) {
2747 		const struct btrfsic_block_link *const l =
2748 		    list_entry(elem_ref_to, struct btrfsic_block_link,
2749 			       node_ref_to);
2750 
2751 		while (cursor_position < indent_level) {
2752 			printk(" ");
2753 			cursor_position++;
2754 		}
2755 		if (l->ref_cnt > 1)
2756 			indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2757 		else
2758 			indent_add = sprintf(buf, " --> ");
2759 		if (indent_level + indent_add >
2760 		    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2761 			printk("[...]\n");
2762 			cursor_position = 0;
2763 			continue;
2764 		}
2765 
2766 		printk(buf);
2767 
2768 		btrfsic_dump_tree_sub(state, l->block_ref_to,
2769 				      indent_level + indent_add);
2770 		cursor_position = 0;
2771 	}
2772 }
2773 
2774 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2775 		struct btrfsic_state *state,
2776 		struct btrfsic_block_data_ctx *next_block_ctx,
2777 		struct btrfsic_block *next_block,
2778 		struct btrfsic_block *from_block,
2779 		u64 parent_generation)
2780 {
2781 	struct btrfsic_block_link *l;
2782 
2783 	l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2784 						next_block_ctx->dev_bytenr,
2785 						from_block->dev_state->bdev,
2786 						from_block->dev_bytenr,
2787 						&state->block_link_hashtable);
2788 	if (NULL == l) {
2789 		l = btrfsic_block_link_alloc();
2790 		if (NULL == l) {
2791 			printk(KERN_INFO
2792 			       "btrfsic: error, kmalloc" " failed!\n");
2793 			return NULL;
2794 		}
2795 
2796 		l->block_ref_to = next_block;
2797 		l->block_ref_from = from_block;
2798 		l->ref_cnt = 1;
2799 		l->parent_generation = parent_generation;
2800 
2801 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2802 			btrfsic_print_add_link(state, l);
2803 
2804 		list_add(&l->node_ref_to, &from_block->ref_to_list);
2805 		list_add(&l->node_ref_from, &next_block->ref_from_list);
2806 
2807 		btrfsic_block_link_hashtable_add(l,
2808 						 &state->block_link_hashtable);
2809 	} else {
2810 		l->ref_cnt++;
2811 		l->parent_generation = parent_generation;
2812 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2813 			btrfsic_print_add_link(state, l);
2814 	}
2815 
2816 	return l;
2817 }
2818 
2819 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2820 		struct btrfsic_state *state,
2821 		struct btrfsic_block_data_ctx *block_ctx,
2822 		const char *additional_string,
2823 		int is_metadata,
2824 		int is_iodone,
2825 		int never_written,
2826 		int mirror_num,
2827 		int *was_created)
2828 {
2829 	struct btrfsic_block *block;
2830 
2831 	block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2832 					       block_ctx->dev_bytenr,
2833 					       &state->block_hashtable);
2834 	if (NULL == block) {
2835 		struct btrfsic_dev_state *dev_state;
2836 
2837 		block = btrfsic_block_alloc();
2838 		if (NULL == block) {
2839 			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2840 			return NULL;
2841 		}
2842 		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2843 		if (NULL == dev_state) {
2844 			printk(KERN_INFO
2845 			       "btrfsic: error, lookup dev_state failed!\n");
2846 			btrfsic_block_free(block);
2847 			return NULL;
2848 		}
2849 		block->dev_state = dev_state;
2850 		block->dev_bytenr = block_ctx->dev_bytenr;
2851 		block->logical_bytenr = block_ctx->start;
2852 		block->is_metadata = is_metadata;
2853 		block->is_iodone = is_iodone;
2854 		block->never_written = never_written;
2855 		block->mirror_num = mirror_num;
2856 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2857 			printk(KERN_INFO
2858 			       "New %s%c-block @%llu (%s/%llu/%d)\n",
2859 			       additional_string,
2860 			       btrfsic_get_block_type(state, block),
2861 			       block->logical_bytenr, dev_state->name,
2862 			       block->dev_bytenr, mirror_num);
2863 		list_add(&block->all_blocks_node, &state->all_blocks_list);
2864 		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2865 		if (NULL != was_created)
2866 			*was_created = 1;
2867 	} else {
2868 		if (NULL != was_created)
2869 			*was_created = 0;
2870 	}
2871 
2872 	return block;
2873 }
2874 
2875 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2876 					   u64 bytenr,
2877 					   struct btrfsic_dev_state *dev_state,
2878 					   u64 dev_bytenr)
2879 {
2880 	int num_copies;
2881 	int mirror_num;
2882 	int ret;
2883 	struct btrfsic_block_data_ctx block_ctx;
2884 	int match = 0;
2885 
2886 	num_copies = btrfs_num_copies(state->root->fs_info,
2887 				      bytenr, state->metablock_size);
2888 
2889 	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2890 		ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2891 					&block_ctx, mirror_num);
2892 		if (ret) {
2893 			printk(KERN_INFO "btrfsic:"
2894 			       " btrfsic_map_block(logical @%llu,"
2895 			       " mirror %d) failed!\n",
2896 			       bytenr, mirror_num);
2897 			continue;
2898 		}
2899 
2900 		if (dev_state->bdev == block_ctx.dev->bdev &&
2901 		    dev_bytenr == block_ctx.dev_bytenr) {
2902 			match++;
2903 			btrfsic_release_block_ctx(&block_ctx);
2904 			break;
2905 		}
2906 		btrfsic_release_block_ctx(&block_ctx);
2907 	}
2908 
2909 	if (!match) {
2910 		printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2911 		       " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2912 		       " phys_bytenr=%llu)!\n",
2913 		       bytenr, dev_state->name, dev_bytenr);
2914 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2915 			ret = btrfsic_map_block(state, bytenr,
2916 						state->metablock_size,
2917 						&block_ctx, mirror_num);
2918 			if (ret)
2919 				continue;
2920 
2921 			printk(KERN_INFO "Read logical bytenr @%llu maps to"
2922 			       " (%s/%llu/%d)\n",
2923 			       bytenr, block_ctx.dev->name,
2924 			       block_ctx.dev_bytenr, mirror_num);
2925 		}
2926 		WARN_ON(1);
2927 	}
2928 }
2929 
2930 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2931 		struct block_device *bdev)
2932 {
2933 	struct btrfsic_dev_state *ds;
2934 
2935 	ds = btrfsic_dev_state_hashtable_lookup(bdev,
2936 						&btrfsic_dev_state_hashtable);
2937 	return ds;
2938 }
2939 
2940 int btrfsic_submit_bh(int rw, struct buffer_head *bh)
2941 {
2942 	struct btrfsic_dev_state *dev_state;
2943 
2944 	if (!btrfsic_is_initialized)
2945 		return submit_bh(rw, bh);
2946 
2947 	mutex_lock(&btrfsic_mutex);
2948 	/* since btrfsic_submit_bh() might also be called before
2949 	 * btrfsic_mount(), this might return NULL */
2950 	dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
2951 
2952 	/* Only called to write the superblock (incl. FLUSH/FUA) */
2953 	if (NULL != dev_state &&
2954 	    (rw & WRITE) && bh->b_size > 0) {
2955 		u64 dev_bytenr;
2956 
2957 		dev_bytenr = 4096 * bh->b_blocknr;
2958 		if (dev_state->state->print_mask &
2959 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2960 			printk(KERN_INFO
2961 			       "submit_bh(rw=0x%x, blocknr=%llu (bytenr %llu),"
2962 			       " size=%zu, data=%p, bdev=%p)\n",
2963 			       rw, (unsigned long long)bh->b_blocknr,
2964 			       dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2965 		btrfsic_process_written_block(dev_state, dev_bytenr,
2966 					      &bh->b_data, 1, NULL,
2967 					      NULL, bh, rw);
2968 	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
2969 		if (dev_state->state->print_mask &
2970 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2971 			printk(KERN_INFO
2972 			       "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
2973 			       rw, bh->b_bdev);
2974 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2975 			if ((dev_state->state->print_mask &
2976 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2977 			      BTRFSIC_PRINT_MASK_VERBOSE)))
2978 				printk(KERN_INFO
2979 				       "btrfsic_submit_bh(%s) with FLUSH"
2980 				       " but dummy block already in use"
2981 				       " (ignored)!\n",
2982 				       dev_state->name);
2983 		} else {
2984 			struct btrfsic_block *const block =
2985 				&dev_state->dummy_block_for_bio_bh_flush;
2986 
2987 			block->is_iodone = 0;
2988 			block->never_written = 0;
2989 			block->iodone_w_error = 0;
2990 			block->flush_gen = dev_state->last_flush_gen + 1;
2991 			block->submit_bio_bh_rw = rw;
2992 			block->orig_bio_bh_private = bh->b_private;
2993 			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2994 			block->next_in_same_bio = NULL;
2995 			bh->b_private = block;
2996 			bh->b_end_io = btrfsic_bh_end_io;
2997 		}
2998 	}
2999 	mutex_unlock(&btrfsic_mutex);
3000 	return submit_bh(rw, bh);
3001 }
3002 
3003 void btrfsic_submit_bio(int rw, struct bio *bio)
3004 {
3005 	struct btrfsic_dev_state *dev_state;
3006 
3007 	if (!btrfsic_is_initialized) {
3008 		submit_bio(rw, bio);
3009 		return;
3010 	}
3011 
3012 	mutex_lock(&btrfsic_mutex);
3013 	/* since btrfsic_submit_bio() is also called before
3014 	 * btrfsic_mount(), this might return NULL */
3015 	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
3016 	if (NULL != dev_state &&
3017 	    (rw & WRITE) && NULL != bio->bi_io_vec) {
3018 		unsigned int i;
3019 		u64 dev_bytenr;
3020 		int bio_is_patched;
3021 		char **mapped_datav;
3022 
3023 		dev_bytenr = 512 * bio->bi_sector;
3024 		bio_is_patched = 0;
3025 		if (dev_state->state->print_mask &
3026 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3027 			printk(KERN_INFO
3028 			       "submit_bio(rw=0x%x, bi_vcnt=%u,"
3029 			       " bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
3030 			       rw, bio->bi_vcnt,
3031 			       (unsigned long long)bio->bi_sector, dev_bytenr,
3032 			       bio->bi_bdev);
3033 
3034 		mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
3035 				       GFP_NOFS);
3036 		if (!mapped_datav)
3037 			goto leave;
3038 		for (i = 0; i < bio->bi_vcnt; i++) {
3039 			BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3040 			mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3041 			if (!mapped_datav[i]) {
3042 				while (i > 0) {
3043 					i--;
3044 					kunmap(bio->bi_io_vec[i].bv_page);
3045 				}
3046 				kfree(mapped_datav);
3047 				goto leave;
3048 			}
3049 			if ((BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3050 			     BTRFSIC_PRINT_MASK_VERBOSE) ==
3051 			    (dev_state->state->print_mask &
3052 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3053 			      BTRFSIC_PRINT_MASK_VERBOSE)))
3054 				printk(KERN_INFO
3055 				       "#%u: page=%p, len=%u, offset=%u\n",
3056 				       i, bio->bi_io_vec[i].bv_page,
3057 				       bio->bi_io_vec[i].bv_len,
3058 				       bio->bi_io_vec[i].bv_offset);
3059 		}
3060 		btrfsic_process_written_block(dev_state, dev_bytenr,
3061 					      mapped_datav, bio->bi_vcnt,
3062 					      bio, &bio_is_patched,
3063 					      NULL, rw);
3064 		while (i > 0) {
3065 			i--;
3066 			kunmap(bio->bi_io_vec[i].bv_page);
3067 		}
3068 		kfree(mapped_datav);
3069 	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3070 		if (dev_state->state->print_mask &
3071 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3072 			printk(KERN_INFO
3073 			       "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3074 			       rw, bio->bi_bdev);
3075 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3076 			if ((dev_state->state->print_mask &
3077 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3078 			      BTRFSIC_PRINT_MASK_VERBOSE)))
3079 				printk(KERN_INFO
3080 				       "btrfsic_submit_bio(%s) with FLUSH"
3081 				       " but dummy block already in use"
3082 				       " (ignored)!\n",
3083 				       dev_state->name);
3084 		} else {
3085 			struct btrfsic_block *const block =
3086 				&dev_state->dummy_block_for_bio_bh_flush;
3087 
3088 			block->is_iodone = 0;
3089 			block->never_written = 0;
3090 			block->iodone_w_error = 0;
3091 			block->flush_gen = dev_state->last_flush_gen + 1;
3092 			block->submit_bio_bh_rw = rw;
3093 			block->orig_bio_bh_private = bio->bi_private;
3094 			block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3095 			block->next_in_same_bio = NULL;
3096 			bio->bi_private = block;
3097 			bio->bi_end_io = btrfsic_bio_end_io;
3098 		}
3099 	}
3100 leave:
3101 	mutex_unlock(&btrfsic_mutex);
3102 
3103 	submit_bio(rw, bio);
3104 }
3105 
3106 int btrfsic_mount(struct btrfs_root *root,
3107 		  struct btrfs_fs_devices *fs_devices,
3108 		  int including_extent_data, u32 print_mask)
3109 {
3110 	int ret;
3111 	struct btrfsic_state *state;
3112 	struct list_head *dev_head = &fs_devices->devices;
3113 	struct btrfs_device *device;
3114 
3115 	if (root->nodesize != root->leafsize) {
3116 		printk(KERN_INFO
3117 		       "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
3118 		       root->nodesize, root->leafsize);
3119 		return -1;
3120 	}
3121 	if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3122 		printk(KERN_INFO
3123 		       "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3124 		       root->nodesize, PAGE_CACHE_SIZE);
3125 		return -1;
3126 	}
3127 	if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3128 		printk(KERN_INFO
3129 		       "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3130 		       root->leafsize, PAGE_CACHE_SIZE);
3131 		return -1;
3132 	}
3133 	if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3134 		printk(KERN_INFO
3135 		       "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3136 		       root->sectorsize, PAGE_CACHE_SIZE);
3137 		return -1;
3138 	}
3139 	state = kzalloc(sizeof(*state), GFP_NOFS);
3140 	if (NULL == state) {
3141 		printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
3142 		return -1;
3143 	}
3144 
3145 	if (!btrfsic_is_initialized) {
3146 		mutex_init(&btrfsic_mutex);
3147 		btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3148 		btrfsic_is_initialized = 1;
3149 	}
3150 	mutex_lock(&btrfsic_mutex);
3151 	state->root = root;
3152 	state->print_mask = print_mask;
3153 	state->include_extent_data = including_extent_data;
3154 	state->csum_size = 0;
3155 	state->metablock_size = root->nodesize;
3156 	state->datablock_size = root->sectorsize;
3157 	INIT_LIST_HEAD(&state->all_blocks_list);
3158 	btrfsic_block_hashtable_init(&state->block_hashtable);
3159 	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3160 	state->max_superblock_generation = 0;
3161 	state->latest_superblock = NULL;
3162 
3163 	list_for_each_entry(device, dev_head, dev_list) {
3164 		struct btrfsic_dev_state *ds;
3165 		char *p;
3166 
3167 		if (!device->bdev || !device->name)
3168 			continue;
3169 
3170 		ds = btrfsic_dev_state_alloc();
3171 		if (NULL == ds) {
3172 			printk(KERN_INFO
3173 			       "btrfs check-integrity: kmalloc() failed!\n");
3174 			mutex_unlock(&btrfsic_mutex);
3175 			return -1;
3176 		}
3177 		ds->bdev = device->bdev;
3178 		ds->state = state;
3179 		bdevname(ds->bdev, ds->name);
3180 		ds->name[BDEVNAME_SIZE - 1] = '\0';
3181 		for (p = ds->name; *p != '\0'; p++);
3182 		while (p > ds->name && *p != '/')
3183 			p--;
3184 		if (*p == '/')
3185 			p++;
3186 		strlcpy(ds->name, p, sizeof(ds->name));
3187 		btrfsic_dev_state_hashtable_add(ds,
3188 						&btrfsic_dev_state_hashtable);
3189 	}
3190 
3191 	ret = btrfsic_process_superblock(state, fs_devices);
3192 	if (0 != ret) {
3193 		mutex_unlock(&btrfsic_mutex);
3194 		btrfsic_unmount(root, fs_devices);
3195 		return ret;
3196 	}
3197 
3198 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3199 		btrfsic_dump_database(state);
3200 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3201 		btrfsic_dump_tree(state);
3202 
3203 	mutex_unlock(&btrfsic_mutex);
3204 	return 0;
3205 }
3206 
3207 void btrfsic_unmount(struct btrfs_root *root,
3208 		     struct btrfs_fs_devices *fs_devices)
3209 {
3210 	struct list_head *elem_all;
3211 	struct list_head *tmp_all;
3212 	struct btrfsic_state *state;
3213 	struct list_head *dev_head = &fs_devices->devices;
3214 	struct btrfs_device *device;
3215 
3216 	if (!btrfsic_is_initialized)
3217 		return;
3218 
3219 	mutex_lock(&btrfsic_mutex);
3220 
3221 	state = NULL;
3222 	list_for_each_entry(device, dev_head, dev_list) {
3223 		struct btrfsic_dev_state *ds;
3224 
3225 		if (!device->bdev || !device->name)
3226 			continue;
3227 
3228 		ds = btrfsic_dev_state_hashtable_lookup(
3229 				device->bdev,
3230 				&btrfsic_dev_state_hashtable);
3231 		if (NULL != ds) {
3232 			state = ds->state;
3233 			btrfsic_dev_state_hashtable_remove(ds);
3234 			btrfsic_dev_state_free(ds);
3235 		}
3236 	}
3237 
3238 	if (NULL == state) {
3239 		printk(KERN_INFO
3240 		       "btrfsic: error, cannot find state information"
3241 		       " on umount!\n");
3242 		mutex_unlock(&btrfsic_mutex);
3243 		return;
3244 	}
3245 
3246 	/*
3247 	 * Don't care about keeping the lists' state up to date,
3248 	 * just free all memory that was allocated dynamically.
3249 	 * Free the blocks and the block_links.
3250 	 */
3251 	list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3252 		struct btrfsic_block *const b_all =
3253 		    list_entry(elem_all, struct btrfsic_block,
3254 			       all_blocks_node);
3255 		struct list_head *elem_ref_to;
3256 		struct list_head *tmp_ref_to;
3257 
3258 		list_for_each_safe(elem_ref_to, tmp_ref_to,
3259 				   &b_all->ref_to_list) {
3260 			struct btrfsic_block_link *const l =
3261 			    list_entry(elem_ref_to,
3262 				       struct btrfsic_block_link,
3263 				       node_ref_to);
3264 
3265 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3266 				btrfsic_print_rem_link(state, l);
3267 
3268 			l->ref_cnt--;
3269 			if (0 == l->ref_cnt)
3270 				btrfsic_block_link_free(l);
3271 		}
3272 
3273 		if (b_all->is_iodone || b_all->never_written)
3274 			btrfsic_block_free(b_all);
3275 		else
3276 			printk(KERN_INFO "btrfs: attempt to free %c-block"
3277 			       " @%llu (%s/%llu/%d) on umount which is"
3278 			       " not yet iodone!\n",
3279 			       btrfsic_get_block_type(state, b_all),
3280 			       b_all->logical_bytenr, b_all->dev_state->name,
3281 			       b_all->dev_bytenr, b_all->mirror_num);
3282 	}
3283 
3284 	mutex_unlock(&btrfsic_mutex);
3285 
3286 	kfree(state);
3287 }
3288