xref: /openbmc/linux/fs/btrfs/check-integrity.c (revision 4da722ca)
1 /*
2  * Copyright (C) STRATO AG 2011.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 
19 /*
20  * This module can be used to catch cases when the btrfs kernel
21  * code executes write requests to the disk that bring the file
22  * system in an inconsistent state. In such a state, a power-loss
23  * or kernel panic event would cause that the data on disk is
24  * lost or at least damaged.
25  *
26  * Code is added that examines all block write requests during
27  * runtime (including writes of the super block). Three rules
28  * are verified and an error is printed on violation of the
29  * rules:
30  * 1. It is not allowed to write a disk block which is
31  *    currently referenced by the super block (either directly
32  *    or indirectly).
33  * 2. When a super block is written, it is verified that all
34  *    referenced (directly or indirectly) blocks fulfill the
35  *    following requirements:
36  *    2a. All referenced blocks have either been present when
37  *        the file system was mounted, (i.e., they have been
38  *        referenced by the super block) or they have been
39  *        written since then and the write completion callback
40  *        was called and no write error was indicated and a
41  *        FLUSH request to the device where these blocks are
42  *        located was received and completed.
43  *    2b. All referenced blocks need to have a generation
44  *        number which is equal to the parent's number.
45  *
46  * One issue that was found using this module was that the log
47  * tree on disk became temporarily corrupted because disk blocks
48  * that had been in use for the log tree had been freed and
49  * reused too early, while being referenced by the written super
50  * block.
51  *
52  * The search term in the kernel log that can be used to filter
53  * on the existence of detected integrity issues is
54  * "btrfs: attempt".
55  *
56  * The integrity check is enabled via mount options. These
57  * mount options are only supported if the integrity check
58  * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
59  *
60  * Example #1, apply integrity checks to all metadata:
61  * mount /dev/sdb1 /mnt -o check_int
62  *
63  * Example #2, apply integrity checks to all metadata and
64  * to data extents:
65  * mount /dev/sdb1 /mnt -o check_int_data
66  *
67  * Example #3, apply integrity checks to all metadata and dump
68  * the tree that the super block references to kernel messages
69  * each time after a super block was written:
70  * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
71  *
72  * If the integrity check tool is included and activated in
73  * the mount options, plenty of kernel memory is used, and
74  * plenty of additional CPU cycles are spent. Enabling this
75  * functionality is not intended for normal use. In most
76  * cases, unless you are a btrfs developer who needs to verify
77  * the integrity of (super)-block write requests, do not
78  * enable the config option BTRFS_FS_CHECK_INTEGRITY to
79  * include and compile the integrity check tool.
80  *
81  * Expect millions of lines of information in the kernel log with an
82  * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
83  * kernel config to at least 26 (which is 64MB). Usually the value is
84  * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
85  * changed like this before LOG_BUF_SHIFT can be set to a high value:
86  * config LOG_BUF_SHIFT
87  *       int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
88  *       range 12 30
89  */
90 
91 #include <linux/sched.h>
92 #include <linux/slab.h>
93 #include <linux/buffer_head.h>
94 #include <linux/mutex.h>
95 #include <linux/genhd.h>
96 #include <linux/blkdev.h>
97 #include <linux/mm.h>
98 #include <linux/string.h>
99 #include "ctree.h"
100 #include "disk-io.h"
101 #include "hash.h"
102 #include "transaction.h"
103 #include "extent_io.h"
104 #include "volumes.h"
105 #include "print-tree.h"
106 #include "locking.h"
107 #include "check-integrity.h"
108 #include "rcu-string.h"
109 #include "compression.h"
110 
111 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
112 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
113 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
114 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
115 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
116 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
117 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
118 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)	/* in characters,
119 							 * excluding " [...]" */
120 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
121 
122 /*
123  * The definition of the bitmask fields for the print_mask.
124  * They are specified with the mount option check_integrity_print_mask.
125  */
126 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE			0x00000001
127 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION		0x00000002
128 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE			0x00000004
129 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE			0x00000008
130 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH			0x00000010
131 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH			0x00000020
132 #define BTRFSIC_PRINT_MASK_VERBOSE				0x00000040
133 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE				0x00000080
134 #define BTRFSIC_PRINT_MASK_INITIAL_TREE				0x00000100
135 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES			0x00000200
136 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE			0x00000400
137 #define BTRFSIC_PRINT_MASK_NUM_COPIES				0x00000800
138 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS		0x00001000
139 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE		0x00002000
140 
141 struct btrfsic_dev_state;
142 struct btrfsic_state;
143 
144 struct btrfsic_block {
145 	u32 magic_num;		/* only used for debug purposes */
146 	unsigned int is_metadata:1;	/* if it is meta-data, not data-data */
147 	unsigned int is_superblock:1;	/* if it is one of the superblocks */
148 	unsigned int is_iodone:1;	/* if is done by lower subsystem */
149 	unsigned int iodone_w_error:1;	/* error was indicated to endio */
150 	unsigned int never_written:1;	/* block was added because it was
151 					 * referenced, not because it was
152 					 * written */
153 	unsigned int mirror_num;	/* large enough to hold
154 					 * BTRFS_SUPER_MIRROR_MAX */
155 	struct btrfsic_dev_state *dev_state;
156 	u64 dev_bytenr;		/* key, physical byte num on disk */
157 	u64 logical_bytenr;	/* logical byte num on disk */
158 	u64 generation;
159 	struct btrfs_disk_key disk_key;	/* extra info to print in case of
160 					 * issues, will not always be correct */
161 	struct list_head collision_resolving_node;	/* list node */
162 	struct list_head all_blocks_node;	/* list node */
163 
164 	/* the following two lists contain block_link items */
165 	struct list_head ref_to_list;	/* list */
166 	struct list_head ref_from_list;	/* list */
167 	struct btrfsic_block *next_in_same_bio;
168 	void *orig_bio_bh_private;
169 	union {
170 		bio_end_io_t *bio;
171 		bh_end_io_t *bh;
172 	} orig_bio_bh_end_io;
173 	int submit_bio_bh_rw;
174 	u64 flush_gen; /* only valid if !never_written */
175 };
176 
177 /*
178  * Elements of this type are allocated dynamically and required because
179  * each block object can refer to and can be ref from multiple blocks.
180  * The key to lookup them in the hashtable is the dev_bytenr of
181  * the block ref to plus the one from the block referred from.
182  * The fact that they are searchable via a hashtable and that a
183  * ref_cnt is maintained is not required for the btrfs integrity
184  * check algorithm itself, it is only used to make the output more
185  * beautiful in case that an error is detected (an error is defined
186  * as a write operation to a block while that block is still referenced).
187  */
188 struct btrfsic_block_link {
189 	u32 magic_num;		/* only used for debug purposes */
190 	u32 ref_cnt;
191 	struct list_head node_ref_to;	/* list node */
192 	struct list_head node_ref_from;	/* list node */
193 	struct list_head collision_resolving_node;	/* list node */
194 	struct btrfsic_block *block_ref_to;
195 	struct btrfsic_block *block_ref_from;
196 	u64 parent_generation;
197 };
198 
199 struct btrfsic_dev_state {
200 	u32 magic_num;		/* only used for debug purposes */
201 	struct block_device *bdev;
202 	struct btrfsic_state *state;
203 	struct list_head collision_resolving_node;	/* list node */
204 	struct btrfsic_block dummy_block_for_bio_bh_flush;
205 	u64 last_flush_gen;
206 	char name[BDEVNAME_SIZE];
207 };
208 
209 struct btrfsic_block_hashtable {
210 	struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
211 };
212 
213 struct btrfsic_block_link_hashtable {
214 	struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
215 };
216 
217 struct btrfsic_dev_state_hashtable {
218 	struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
219 };
220 
221 struct btrfsic_block_data_ctx {
222 	u64 start;		/* virtual bytenr */
223 	u64 dev_bytenr;		/* physical bytenr on device */
224 	u32 len;
225 	struct btrfsic_dev_state *dev;
226 	char **datav;
227 	struct page **pagev;
228 	void *mem_to_free;
229 };
230 
231 /* This structure is used to implement recursion without occupying
232  * any stack space, refer to btrfsic_process_metablock() */
233 struct btrfsic_stack_frame {
234 	u32 magic;
235 	u32 nr;
236 	int error;
237 	int i;
238 	int limit_nesting;
239 	int num_copies;
240 	int mirror_num;
241 	struct btrfsic_block *block;
242 	struct btrfsic_block_data_ctx *block_ctx;
243 	struct btrfsic_block *next_block;
244 	struct btrfsic_block_data_ctx next_block_ctx;
245 	struct btrfs_header *hdr;
246 	struct btrfsic_stack_frame *prev;
247 };
248 
249 /* Some state per mounted filesystem */
250 struct btrfsic_state {
251 	u32 print_mask;
252 	int include_extent_data;
253 	int csum_size;
254 	struct list_head all_blocks_list;
255 	struct btrfsic_block_hashtable block_hashtable;
256 	struct btrfsic_block_link_hashtable block_link_hashtable;
257 	struct btrfs_fs_info *fs_info;
258 	u64 max_superblock_generation;
259 	struct btrfsic_block *latest_superblock;
260 	u32 metablock_size;
261 	u32 datablock_size;
262 };
263 
264 static void btrfsic_block_init(struct btrfsic_block *b);
265 static struct btrfsic_block *btrfsic_block_alloc(void);
266 static void btrfsic_block_free(struct btrfsic_block *b);
267 static void btrfsic_block_link_init(struct btrfsic_block_link *n);
268 static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
269 static void btrfsic_block_link_free(struct btrfsic_block_link *n);
270 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
271 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
272 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
273 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
274 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
275 					struct btrfsic_block_hashtable *h);
276 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
277 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
278 		struct block_device *bdev,
279 		u64 dev_bytenr,
280 		struct btrfsic_block_hashtable *h);
281 static void btrfsic_block_link_hashtable_init(
282 		struct btrfsic_block_link_hashtable *h);
283 static void btrfsic_block_link_hashtable_add(
284 		struct btrfsic_block_link *l,
285 		struct btrfsic_block_link_hashtable *h);
286 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
287 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
288 		struct block_device *bdev_ref_to,
289 		u64 dev_bytenr_ref_to,
290 		struct block_device *bdev_ref_from,
291 		u64 dev_bytenr_ref_from,
292 		struct btrfsic_block_link_hashtable *h);
293 static void btrfsic_dev_state_hashtable_init(
294 		struct btrfsic_dev_state_hashtable *h);
295 static void btrfsic_dev_state_hashtable_add(
296 		struct btrfsic_dev_state *ds,
297 		struct btrfsic_dev_state_hashtable *h);
298 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
299 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
300 		struct block_device *bdev,
301 		struct btrfsic_dev_state_hashtable *h);
302 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
303 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
304 static int btrfsic_process_superblock(struct btrfsic_state *state,
305 				      struct btrfs_fs_devices *fs_devices);
306 static int btrfsic_process_metablock(struct btrfsic_state *state,
307 				     struct btrfsic_block *block,
308 				     struct btrfsic_block_data_ctx *block_ctx,
309 				     int limit_nesting, int force_iodone_flag);
310 static void btrfsic_read_from_block_data(
311 	struct btrfsic_block_data_ctx *block_ctx,
312 	void *dst, u32 offset, size_t len);
313 static int btrfsic_create_link_to_next_block(
314 		struct btrfsic_state *state,
315 		struct btrfsic_block *block,
316 		struct btrfsic_block_data_ctx
317 		*block_ctx, u64 next_bytenr,
318 		int limit_nesting,
319 		struct btrfsic_block_data_ctx *next_block_ctx,
320 		struct btrfsic_block **next_blockp,
321 		int force_iodone_flag,
322 		int *num_copiesp, int *mirror_nump,
323 		struct btrfs_disk_key *disk_key,
324 		u64 parent_generation);
325 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
326 				      struct btrfsic_block *block,
327 				      struct btrfsic_block_data_ctx *block_ctx,
328 				      u32 item_offset, int force_iodone_flag);
329 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
330 			     struct btrfsic_block_data_ctx *block_ctx_out,
331 			     int mirror_num);
332 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
333 static int btrfsic_read_block(struct btrfsic_state *state,
334 			      struct btrfsic_block_data_ctx *block_ctx);
335 static void btrfsic_dump_database(struct btrfsic_state *state);
336 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
337 				     char **datav, unsigned int num_pages);
338 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
339 					  u64 dev_bytenr, char **mapped_datav,
340 					  unsigned int num_pages,
341 					  struct bio *bio, int *bio_is_patched,
342 					  struct buffer_head *bh,
343 					  int submit_bio_bh_rw);
344 static int btrfsic_process_written_superblock(
345 		struct btrfsic_state *state,
346 		struct btrfsic_block *const block,
347 		struct btrfs_super_block *const super_hdr);
348 static void btrfsic_bio_end_io(struct bio *bp);
349 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
350 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
351 					      const struct btrfsic_block *block,
352 					      int recursion_level);
353 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
354 					struct btrfsic_block *const block,
355 					int recursion_level);
356 static void btrfsic_print_add_link(const struct btrfsic_state *state,
357 				   const struct btrfsic_block_link *l);
358 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
359 				   const struct btrfsic_block_link *l);
360 static char btrfsic_get_block_type(const struct btrfsic_state *state,
361 				   const struct btrfsic_block *block);
362 static void btrfsic_dump_tree(const struct btrfsic_state *state);
363 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
364 				  const struct btrfsic_block *block,
365 				  int indent_level);
366 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
367 		struct btrfsic_state *state,
368 		struct btrfsic_block_data_ctx *next_block_ctx,
369 		struct btrfsic_block *next_block,
370 		struct btrfsic_block *from_block,
371 		u64 parent_generation);
372 static struct btrfsic_block *btrfsic_block_lookup_or_add(
373 		struct btrfsic_state *state,
374 		struct btrfsic_block_data_ctx *block_ctx,
375 		const char *additional_string,
376 		int is_metadata,
377 		int is_iodone,
378 		int never_written,
379 		int mirror_num,
380 		int *was_created);
381 static int btrfsic_process_superblock_dev_mirror(
382 		struct btrfsic_state *state,
383 		struct btrfsic_dev_state *dev_state,
384 		struct btrfs_device *device,
385 		int superblock_mirror_num,
386 		struct btrfsic_dev_state **selected_dev_state,
387 		struct btrfs_super_block *selected_super);
388 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
389 		struct block_device *bdev);
390 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
391 					   u64 bytenr,
392 					   struct btrfsic_dev_state *dev_state,
393 					   u64 dev_bytenr);
394 
395 static struct mutex btrfsic_mutex;
396 static int btrfsic_is_initialized;
397 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
398 
399 
400 static void btrfsic_block_init(struct btrfsic_block *b)
401 {
402 	b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
403 	b->dev_state = NULL;
404 	b->dev_bytenr = 0;
405 	b->logical_bytenr = 0;
406 	b->generation = BTRFSIC_GENERATION_UNKNOWN;
407 	b->disk_key.objectid = 0;
408 	b->disk_key.type = 0;
409 	b->disk_key.offset = 0;
410 	b->is_metadata = 0;
411 	b->is_superblock = 0;
412 	b->is_iodone = 0;
413 	b->iodone_w_error = 0;
414 	b->never_written = 0;
415 	b->mirror_num = 0;
416 	b->next_in_same_bio = NULL;
417 	b->orig_bio_bh_private = NULL;
418 	b->orig_bio_bh_end_io.bio = NULL;
419 	INIT_LIST_HEAD(&b->collision_resolving_node);
420 	INIT_LIST_HEAD(&b->all_blocks_node);
421 	INIT_LIST_HEAD(&b->ref_to_list);
422 	INIT_LIST_HEAD(&b->ref_from_list);
423 	b->submit_bio_bh_rw = 0;
424 	b->flush_gen = 0;
425 }
426 
427 static struct btrfsic_block *btrfsic_block_alloc(void)
428 {
429 	struct btrfsic_block *b;
430 
431 	b = kzalloc(sizeof(*b), GFP_NOFS);
432 	if (NULL != b)
433 		btrfsic_block_init(b);
434 
435 	return b;
436 }
437 
438 static void btrfsic_block_free(struct btrfsic_block *b)
439 {
440 	BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
441 	kfree(b);
442 }
443 
444 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
445 {
446 	l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
447 	l->ref_cnt = 1;
448 	INIT_LIST_HEAD(&l->node_ref_to);
449 	INIT_LIST_HEAD(&l->node_ref_from);
450 	INIT_LIST_HEAD(&l->collision_resolving_node);
451 	l->block_ref_to = NULL;
452 	l->block_ref_from = NULL;
453 }
454 
455 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
456 {
457 	struct btrfsic_block_link *l;
458 
459 	l = kzalloc(sizeof(*l), GFP_NOFS);
460 	if (NULL != l)
461 		btrfsic_block_link_init(l);
462 
463 	return l;
464 }
465 
466 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
467 {
468 	BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
469 	kfree(l);
470 }
471 
472 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
473 {
474 	ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
475 	ds->bdev = NULL;
476 	ds->state = NULL;
477 	ds->name[0] = '\0';
478 	INIT_LIST_HEAD(&ds->collision_resolving_node);
479 	ds->last_flush_gen = 0;
480 	btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
481 	ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
482 	ds->dummy_block_for_bio_bh_flush.dev_state = ds;
483 }
484 
485 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
486 {
487 	struct btrfsic_dev_state *ds;
488 
489 	ds = kzalloc(sizeof(*ds), GFP_NOFS);
490 	if (NULL != ds)
491 		btrfsic_dev_state_init(ds);
492 
493 	return ds;
494 }
495 
496 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
497 {
498 	BUG_ON(!(NULL == ds ||
499 		 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
500 	kfree(ds);
501 }
502 
503 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
504 {
505 	int i;
506 
507 	for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
508 		INIT_LIST_HEAD(h->table + i);
509 }
510 
511 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
512 					struct btrfsic_block_hashtable *h)
513 {
514 	const unsigned int hashval =
515 	    (((unsigned int)(b->dev_bytenr >> 16)) ^
516 	     ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
517 	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
518 
519 	list_add(&b->collision_resolving_node, h->table + hashval);
520 }
521 
522 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
523 {
524 	list_del(&b->collision_resolving_node);
525 }
526 
527 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
528 		struct block_device *bdev,
529 		u64 dev_bytenr,
530 		struct btrfsic_block_hashtable *h)
531 {
532 	const unsigned int hashval =
533 	    (((unsigned int)(dev_bytenr >> 16)) ^
534 	     ((unsigned int)((uintptr_t)bdev))) &
535 	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
536 	struct btrfsic_block *b;
537 
538 	list_for_each_entry(b, h->table + hashval, collision_resolving_node) {
539 		if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
540 			return b;
541 	}
542 
543 	return NULL;
544 }
545 
546 static void btrfsic_block_link_hashtable_init(
547 		struct btrfsic_block_link_hashtable *h)
548 {
549 	int i;
550 
551 	for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
552 		INIT_LIST_HEAD(h->table + i);
553 }
554 
555 static void btrfsic_block_link_hashtable_add(
556 		struct btrfsic_block_link *l,
557 		struct btrfsic_block_link_hashtable *h)
558 {
559 	const unsigned int hashval =
560 	    (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
561 	     ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
562 	     ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
563 	     ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
564 	     & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
565 
566 	BUG_ON(NULL == l->block_ref_to);
567 	BUG_ON(NULL == l->block_ref_from);
568 	list_add(&l->collision_resolving_node, h->table + hashval);
569 }
570 
571 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
572 {
573 	list_del(&l->collision_resolving_node);
574 }
575 
576 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
577 		struct block_device *bdev_ref_to,
578 		u64 dev_bytenr_ref_to,
579 		struct block_device *bdev_ref_from,
580 		u64 dev_bytenr_ref_from,
581 		struct btrfsic_block_link_hashtable *h)
582 {
583 	const unsigned int hashval =
584 	    (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
585 	     ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
586 	     ((unsigned int)((uintptr_t)bdev_ref_to)) ^
587 	     ((unsigned int)((uintptr_t)bdev_ref_from))) &
588 	     (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
589 	struct btrfsic_block_link *l;
590 
591 	list_for_each_entry(l, h->table + hashval, collision_resolving_node) {
592 		BUG_ON(NULL == l->block_ref_to);
593 		BUG_ON(NULL == l->block_ref_from);
594 		if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
595 		    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
596 		    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
597 		    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
598 			return l;
599 	}
600 
601 	return NULL;
602 }
603 
604 static void btrfsic_dev_state_hashtable_init(
605 		struct btrfsic_dev_state_hashtable *h)
606 {
607 	int i;
608 
609 	for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
610 		INIT_LIST_HEAD(h->table + i);
611 }
612 
613 static void btrfsic_dev_state_hashtable_add(
614 		struct btrfsic_dev_state *ds,
615 		struct btrfsic_dev_state_hashtable *h)
616 {
617 	const unsigned int hashval =
618 	    (((unsigned int)((uintptr_t)ds->bdev)) &
619 	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
620 
621 	list_add(&ds->collision_resolving_node, h->table + hashval);
622 }
623 
624 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
625 {
626 	list_del(&ds->collision_resolving_node);
627 }
628 
629 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
630 		struct block_device *bdev,
631 		struct btrfsic_dev_state_hashtable *h)
632 {
633 	const unsigned int hashval =
634 	    (((unsigned int)((uintptr_t)bdev)) &
635 	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
636 	struct btrfsic_dev_state *ds;
637 
638 	list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
639 		if (ds->bdev == bdev)
640 			return ds;
641 	}
642 
643 	return NULL;
644 }
645 
646 static int btrfsic_process_superblock(struct btrfsic_state *state,
647 				      struct btrfs_fs_devices *fs_devices)
648 {
649 	struct btrfs_fs_info *fs_info = state->fs_info;
650 	struct btrfs_super_block *selected_super;
651 	struct list_head *dev_head = &fs_devices->devices;
652 	struct btrfs_device *device;
653 	struct btrfsic_dev_state *selected_dev_state = NULL;
654 	int ret = 0;
655 	int pass;
656 
657 	BUG_ON(NULL == state);
658 	selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
659 	if (NULL == selected_super) {
660 		pr_info("btrfsic: error, kmalloc failed!\n");
661 		return -ENOMEM;
662 	}
663 
664 	list_for_each_entry(device, dev_head, dev_list) {
665 		int i;
666 		struct btrfsic_dev_state *dev_state;
667 
668 		if (!device->bdev || !device->name)
669 			continue;
670 
671 		dev_state = btrfsic_dev_state_lookup(device->bdev);
672 		BUG_ON(NULL == dev_state);
673 		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
674 			ret = btrfsic_process_superblock_dev_mirror(
675 					state, dev_state, device, i,
676 					&selected_dev_state, selected_super);
677 			if (0 != ret && 0 == i) {
678 				kfree(selected_super);
679 				return ret;
680 			}
681 		}
682 	}
683 
684 	if (NULL == state->latest_superblock) {
685 		pr_info("btrfsic: no superblock found!\n");
686 		kfree(selected_super);
687 		return -1;
688 	}
689 
690 	state->csum_size = btrfs_super_csum_size(selected_super);
691 
692 	for (pass = 0; pass < 3; pass++) {
693 		int num_copies;
694 		int mirror_num;
695 		u64 next_bytenr;
696 
697 		switch (pass) {
698 		case 0:
699 			next_bytenr = btrfs_super_root(selected_super);
700 			if (state->print_mask &
701 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
702 				pr_info("root@%llu\n", next_bytenr);
703 			break;
704 		case 1:
705 			next_bytenr = btrfs_super_chunk_root(selected_super);
706 			if (state->print_mask &
707 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
708 				pr_info("chunk@%llu\n", next_bytenr);
709 			break;
710 		case 2:
711 			next_bytenr = btrfs_super_log_root(selected_super);
712 			if (0 == next_bytenr)
713 				continue;
714 			if (state->print_mask &
715 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
716 				pr_info("log@%llu\n", next_bytenr);
717 			break;
718 		}
719 
720 		num_copies = btrfs_num_copies(fs_info, next_bytenr,
721 					      state->metablock_size);
722 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
723 			pr_info("num_copies(log_bytenr=%llu) = %d\n",
724 			       next_bytenr, num_copies);
725 
726 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
727 			struct btrfsic_block *next_block;
728 			struct btrfsic_block_data_ctx tmp_next_block_ctx;
729 			struct btrfsic_block_link *l;
730 
731 			ret = btrfsic_map_block(state, next_bytenr,
732 						state->metablock_size,
733 						&tmp_next_block_ctx,
734 						mirror_num);
735 			if (ret) {
736 				pr_info("btrfsic: btrfsic_map_block(root @%llu, mirror %d) failed!\n",
737 				       next_bytenr, mirror_num);
738 				kfree(selected_super);
739 				return -1;
740 			}
741 
742 			next_block = btrfsic_block_hashtable_lookup(
743 					tmp_next_block_ctx.dev->bdev,
744 					tmp_next_block_ctx.dev_bytenr,
745 					&state->block_hashtable);
746 			BUG_ON(NULL == next_block);
747 
748 			l = btrfsic_block_link_hashtable_lookup(
749 					tmp_next_block_ctx.dev->bdev,
750 					tmp_next_block_ctx.dev_bytenr,
751 					state->latest_superblock->dev_state->
752 					bdev,
753 					state->latest_superblock->dev_bytenr,
754 					&state->block_link_hashtable);
755 			BUG_ON(NULL == l);
756 
757 			ret = btrfsic_read_block(state, &tmp_next_block_ctx);
758 			if (ret < (int)PAGE_SIZE) {
759 				pr_info("btrfsic: read @logical %llu failed!\n",
760 				       tmp_next_block_ctx.start);
761 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
762 				kfree(selected_super);
763 				return -1;
764 			}
765 
766 			ret = btrfsic_process_metablock(state,
767 							next_block,
768 							&tmp_next_block_ctx,
769 							BTRFS_MAX_LEVEL + 3, 1);
770 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
771 		}
772 	}
773 
774 	kfree(selected_super);
775 	return ret;
776 }
777 
778 static int btrfsic_process_superblock_dev_mirror(
779 		struct btrfsic_state *state,
780 		struct btrfsic_dev_state *dev_state,
781 		struct btrfs_device *device,
782 		int superblock_mirror_num,
783 		struct btrfsic_dev_state **selected_dev_state,
784 		struct btrfs_super_block *selected_super)
785 {
786 	struct btrfs_fs_info *fs_info = state->fs_info;
787 	struct btrfs_super_block *super_tmp;
788 	u64 dev_bytenr;
789 	struct buffer_head *bh;
790 	struct btrfsic_block *superblock_tmp;
791 	int pass;
792 	struct block_device *const superblock_bdev = device->bdev;
793 
794 	/* super block bytenr is always the unmapped device bytenr */
795 	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
796 	if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
797 		return -1;
798 	bh = __bread(superblock_bdev, dev_bytenr / 4096,
799 		     BTRFS_SUPER_INFO_SIZE);
800 	if (NULL == bh)
801 		return -1;
802 	super_tmp = (struct btrfs_super_block *)
803 	    (bh->b_data + (dev_bytenr & 4095));
804 
805 	if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
806 	    btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
807 	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
808 	    btrfs_super_nodesize(super_tmp) != state->metablock_size ||
809 	    btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
810 		brelse(bh);
811 		return 0;
812 	}
813 
814 	superblock_tmp =
815 	    btrfsic_block_hashtable_lookup(superblock_bdev,
816 					   dev_bytenr,
817 					   &state->block_hashtable);
818 	if (NULL == superblock_tmp) {
819 		superblock_tmp = btrfsic_block_alloc();
820 		if (NULL == superblock_tmp) {
821 			pr_info("btrfsic: error, kmalloc failed!\n");
822 			brelse(bh);
823 			return -1;
824 		}
825 		/* for superblock, only the dev_bytenr makes sense */
826 		superblock_tmp->dev_bytenr = dev_bytenr;
827 		superblock_tmp->dev_state = dev_state;
828 		superblock_tmp->logical_bytenr = dev_bytenr;
829 		superblock_tmp->generation = btrfs_super_generation(super_tmp);
830 		superblock_tmp->is_metadata = 1;
831 		superblock_tmp->is_superblock = 1;
832 		superblock_tmp->is_iodone = 1;
833 		superblock_tmp->never_written = 0;
834 		superblock_tmp->mirror_num = 1 + superblock_mirror_num;
835 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
836 			btrfs_info_in_rcu(fs_info,
837 				"new initial S-block (bdev %p, %s) @%llu (%s/%llu/%d)",
838 				     superblock_bdev,
839 				     rcu_str_deref(device->name), dev_bytenr,
840 				     dev_state->name, dev_bytenr,
841 				     superblock_mirror_num);
842 		list_add(&superblock_tmp->all_blocks_node,
843 			 &state->all_blocks_list);
844 		btrfsic_block_hashtable_add(superblock_tmp,
845 					    &state->block_hashtable);
846 	}
847 
848 	/* select the one with the highest generation field */
849 	if (btrfs_super_generation(super_tmp) >
850 	    state->max_superblock_generation ||
851 	    0 == state->max_superblock_generation) {
852 		memcpy(selected_super, super_tmp, sizeof(*selected_super));
853 		*selected_dev_state = dev_state;
854 		state->max_superblock_generation =
855 		    btrfs_super_generation(super_tmp);
856 		state->latest_superblock = superblock_tmp;
857 	}
858 
859 	for (pass = 0; pass < 3; pass++) {
860 		u64 next_bytenr;
861 		int num_copies;
862 		int mirror_num;
863 		const char *additional_string = NULL;
864 		struct btrfs_disk_key tmp_disk_key;
865 
866 		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
867 		tmp_disk_key.offset = 0;
868 		switch (pass) {
869 		case 0:
870 			btrfs_set_disk_key_objectid(&tmp_disk_key,
871 						    BTRFS_ROOT_TREE_OBJECTID);
872 			additional_string = "initial root ";
873 			next_bytenr = btrfs_super_root(super_tmp);
874 			break;
875 		case 1:
876 			btrfs_set_disk_key_objectid(&tmp_disk_key,
877 						    BTRFS_CHUNK_TREE_OBJECTID);
878 			additional_string = "initial chunk ";
879 			next_bytenr = btrfs_super_chunk_root(super_tmp);
880 			break;
881 		case 2:
882 			btrfs_set_disk_key_objectid(&tmp_disk_key,
883 						    BTRFS_TREE_LOG_OBJECTID);
884 			additional_string = "initial log ";
885 			next_bytenr = btrfs_super_log_root(super_tmp);
886 			if (0 == next_bytenr)
887 				continue;
888 			break;
889 		}
890 
891 		num_copies = btrfs_num_copies(fs_info, next_bytenr,
892 					      state->metablock_size);
893 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
894 			pr_info("num_copies(log_bytenr=%llu) = %d\n",
895 			       next_bytenr, num_copies);
896 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
897 			struct btrfsic_block *next_block;
898 			struct btrfsic_block_data_ctx tmp_next_block_ctx;
899 			struct btrfsic_block_link *l;
900 
901 			if (btrfsic_map_block(state, next_bytenr,
902 					      state->metablock_size,
903 					      &tmp_next_block_ctx,
904 					      mirror_num)) {
905 				pr_info("btrfsic: btrfsic_map_block(bytenr @%llu, mirror %d) failed!\n",
906 				       next_bytenr, mirror_num);
907 				brelse(bh);
908 				return -1;
909 			}
910 
911 			next_block = btrfsic_block_lookup_or_add(
912 					state, &tmp_next_block_ctx,
913 					additional_string, 1, 1, 0,
914 					mirror_num, NULL);
915 			if (NULL == next_block) {
916 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
917 				brelse(bh);
918 				return -1;
919 			}
920 
921 			next_block->disk_key = tmp_disk_key;
922 			next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
923 			l = btrfsic_block_link_lookup_or_add(
924 					state, &tmp_next_block_ctx,
925 					next_block, superblock_tmp,
926 					BTRFSIC_GENERATION_UNKNOWN);
927 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
928 			if (NULL == l) {
929 				brelse(bh);
930 				return -1;
931 			}
932 		}
933 	}
934 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
935 		btrfsic_dump_tree_sub(state, superblock_tmp, 0);
936 
937 	brelse(bh);
938 	return 0;
939 }
940 
941 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
942 {
943 	struct btrfsic_stack_frame *sf;
944 
945 	sf = kzalloc(sizeof(*sf), GFP_NOFS);
946 	if (NULL == sf)
947 		pr_info("btrfsic: alloc memory failed!\n");
948 	else
949 		sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
950 	return sf;
951 }
952 
953 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
954 {
955 	BUG_ON(!(NULL == sf ||
956 		 BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
957 	kfree(sf);
958 }
959 
960 static int btrfsic_process_metablock(
961 		struct btrfsic_state *state,
962 		struct btrfsic_block *const first_block,
963 		struct btrfsic_block_data_ctx *const first_block_ctx,
964 		int first_limit_nesting, int force_iodone_flag)
965 {
966 	struct btrfsic_stack_frame initial_stack_frame = { 0 };
967 	struct btrfsic_stack_frame *sf;
968 	struct btrfsic_stack_frame *next_stack;
969 	struct btrfs_header *const first_hdr =
970 		(struct btrfs_header *)first_block_ctx->datav[0];
971 
972 	BUG_ON(!first_hdr);
973 	sf = &initial_stack_frame;
974 	sf->error = 0;
975 	sf->i = -1;
976 	sf->limit_nesting = first_limit_nesting;
977 	sf->block = first_block;
978 	sf->block_ctx = first_block_ctx;
979 	sf->next_block = NULL;
980 	sf->hdr = first_hdr;
981 	sf->prev = NULL;
982 
983 continue_with_new_stack_frame:
984 	sf->block->generation = le64_to_cpu(sf->hdr->generation);
985 	if (0 == sf->hdr->level) {
986 		struct btrfs_leaf *const leafhdr =
987 		    (struct btrfs_leaf *)sf->hdr;
988 
989 		if (-1 == sf->i) {
990 			sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
991 
992 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
993 				pr_info("leaf %llu items %d generation %llu owner %llu\n",
994 				       sf->block_ctx->start, sf->nr,
995 				       btrfs_stack_header_generation(
996 					       &leafhdr->header),
997 				       btrfs_stack_header_owner(
998 					       &leafhdr->header));
999 		}
1000 
1001 continue_with_current_leaf_stack_frame:
1002 		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1003 			sf->i++;
1004 			sf->num_copies = 0;
1005 		}
1006 
1007 		if (sf->i < sf->nr) {
1008 			struct btrfs_item disk_item;
1009 			u32 disk_item_offset =
1010 				(uintptr_t)(leafhdr->items + sf->i) -
1011 				(uintptr_t)leafhdr;
1012 			struct btrfs_disk_key *disk_key;
1013 			u8 type;
1014 			u32 item_offset;
1015 			u32 item_size;
1016 
1017 			if (disk_item_offset + sizeof(struct btrfs_item) >
1018 			    sf->block_ctx->len) {
1019 leaf_item_out_of_bounce_error:
1020 				pr_info("btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1021 				       sf->block_ctx->start,
1022 				       sf->block_ctx->dev->name);
1023 				goto one_stack_frame_backwards;
1024 			}
1025 			btrfsic_read_from_block_data(sf->block_ctx,
1026 						     &disk_item,
1027 						     disk_item_offset,
1028 						     sizeof(struct btrfs_item));
1029 			item_offset = btrfs_stack_item_offset(&disk_item);
1030 			item_size = btrfs_stack_item_size(&disk_item);
1031 			disk_key = &disk_item.key;
1032 			type = btrfs_disk_key_type(disk_key);
1033 
1034 			if (BTRFS_ROOT_ITEM_KEY == type) {
1035 				struct btrfs_root_item root_item;
1036 				u32 root_item_offset;
1037 				u64 next_bytenr;
1038 
1039 				root_item_offset = item_offset +
1040 					offsetof(struct btrfs_leaf, items);
1041 				if (root_item_offset + item_size >
1042 				    sf->block_ctx->len)
1043 					goto leaf_item_out_of_bounce_error;
1044 				btrfsic_read_from_block_data(
1045 					sf->block_ctx, &root_item,
1046 					root_item_offset,
1047 					item_size);
1048 				next_bytenr = btrfs_root_bytenr(&root_item);
1049 
1050 				sf->error =
1051 				    btrfsic_create_link_to_next_block(
1052 						state,
1053 						sf->block,
1054 						sf->block_ctx,
1055 						next_bytenr,
1056 						sf->limit_nesting,
1057 						&sf->next_block_ctx,
1058 						&sf->next_block,
1059 						force_iodone_flag,
1060 						&sf->num_copies,
1061 						&sf->mirror_num,
1062 						disk_key,
1063 						btrfs_root_generation(
1064 						&root_item));
1065 				if (sf->error)
1066 					goto one_stack_frame_backwards;
1067 
1068 				if (NULL != sf->next_block) {
1069 					struct btrfs_header *const next_hdr =
1070 					    (struct btrfs_header *)
1071 					    sf->next_block_ctx.datav[0];
1072 
1073 					next_stack =
1074 					    btrfsic_stack_frame_alloc();
1075 					if (NULL == next_stack) {
1076 						sf->error = -1;
1077 						btrfsic_release_block_ctx(
1078 								&sf->
1079 								next_block_ctx);
1080 						goto one_stack_frame_backwards;
1081 					}
1082 
1083 					next_stack->i = -1;
1084 					next_stack->block = sf->next_block;
1085 					next_stack->block_ctx =
1086 					    &sf->next_block_ctx;
1087 					next_stack->next_block = NULL;
1088 					next_stack->hdr = next_hdr;
1089 					next_stack->limit_nesting =
1090 					    sf->limit_nesting - 1;
1091 					next_stack->prev = sf;
1092 					sf = next_stack;
1093 					goto continue_with_new_stack_frame;
1094 				}
1095 			} else if (BTRFS_EXTENT_DATA_KEY == type &&
1096 				   state->include_extent_data) {
1097 				sf->error = btrfsic_handle_extent_data(
1098 						state,
1099 						sf->block,
1100 						sf->block_ctx,
1101 						item_offset,
1102 						force_iodone_flag);
1103 				if (sf->error)
1104 					goto one_stack_frame_backwards;
1105 			}
1106 
1107 			goto continue_with_current_leaf_stack_frame;
1108 		}
1109 	} else {
1110 		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1111 
1112 		if (-1 == sf->i) {
1113 			sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1114 
1115 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1116 				pr_info("node %llu level %d items %d generation %llu owner %llu\n",
1117 				       sf->block_ctx->start,
1118 				       nodehdr->header.level, sf->nr,
1119 				       btrfs_stack_header_generation(
1120 				       &nodehdr->header),
1121 				       btrfs_stack_header_owner(
1122 				       &nodehdr->header));
1123 		}
1124 
1125 continue_with_current_node_stack_frame:
1126 		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1127 			sf->i++;
1128 			sf->num_copies = 0;
1129 		}
1130 
1131 		if (sf->i < sf->nr) {
1132 			struct btrfs_key_ptr key_ptr;
1133 			u32 key_ptr_offset;
1134 			u64 next_bytenr;
1135 
1136 			key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1137 					  (uintptr_t)nodehdr;
1138 			if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1139 			    sf->block_ctx->len) {
1140 				pr_info("btrfsic: node item out of bounce at logical %llu, dev %s\n",
1141 				       sf->block_ctx->start,
1142 				       sf->block_ctx->dev->name);
1143 				goto one_stack_frame_backwards;
1144 			}
1145 			btrfsic_read_from_block_data(
1146 				sf->block_ctx, &key_ptr, key_ptr_offset,
1147 				sizeof(struct btrfs_key_ptr));
1148 			next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1149 
1150 			sf->error = btrfsic_create_link_to_next_block(
1151 					state,
1152 					sf->block,
1153 					sf->block_ctx,
1154 					next_bytenr,
1155 					sf->limit_nesting,
1156 					&sf->next_block_ctx,
1157 					&sf->next_block,
1158 					force_iodone_flag,
1159 					&sf->num_copies,
1160 					&sf->mirror_num,
1161 					&key_ptr.key,
1162 					btrfs_stack_key_generation(&key_ptr));
1163 			if (sf->error)
1164 				goto one_stack_frame_backwards;
1165 
1166 			if (NULL != sf->next_block) {
1167 				struct btrfs_header *const next_hdr =
1168 				    (struct btrfs_header *)
1169 				    sf->next_block_ctx.datav[0];
1170 
1171 				next_stack = btrfsic_stack_frame_alloc();
1172 				if (NULL == next_stack) {
1173 					sf->error = -1;
1174 					goto one_stack_frame_backwards;
1175 				}
1176 
1177 				next_stack->i = -1;
1178 				next_stack->block = sf->next_block;
1179 				next_stack->block_ctx = &sf->next_block_ctx;
1180 				next_stack->next_block = NULL;
1181 				next_stack->hdr = next_hdr;
1182 				next_stack->limit_nesting =
1183 				    sf->limit_nesting - 1;
1184 				next_stack->prev = sf;
1185 				sf = next_stack;
1186 				goto continue_with_new_stack_frame;
1187 			}
1188 
1189 			goto continue_with_current_node_stack_frame;
1190 		}
1191 	}
1192 
1193 one_stack_frame_backwards:
1194 	if (NULL != sf->prev) {
1195 		struct btrfsic_stack_frame *const prev = sf->prev;
1196 
1197 		/* the one for the initial block is freed in the caller */
1198 		btrfsic_release_block_ctx(sf->block_ctx);
1199 
1200 		if (sf->error) {
1201 			prev->error = sf->error;
1202 			btrfsic_stack_frame_free(sf);
1203 			sf = prev;
1204 			goto one_stack_frame_backwards;
1205 		}
1206 
1207 		btrfsic_stack_frame_free(sf);
1208 		sf = prev;
1209 		goto continue_with_new_stack_frame;
1210 	} else {
1211 		BUG_ON(&initial_stack_frame != sf);
1212 	}
1213 
1214 	return sf->error;
1215 }
1216 
1217 static void btrfsic_read_from_block_data(
1218 	struct btrfsic_block_data_ctx *block_ctx,
1219 	void *dstv, u32 offset, size_t len)
1220 {
1221 	size_t cur;
1222 	size_t offset_in_page;
1223 	char *kaddr;
1224 	char *dst = (char *)dstv;
1225 	size_t start_offset = block_ctx->start & ((u64)PAGE_SIZE - 1);
1226 	unsigned long i = (start_offset + offset) >> PAGE_SHIFT;
1227 
1228 	WARN_ON(offset + len > block_ctx->len);
1229 	offset_in_page = (start_offset + offset) & (PAGE_SIZE - 1);
1230 
1231 	while (len > 0) {
1232 		cur = min(len, ((size_t)PAGE_SIZE - offset_in_page));
1233 		BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_SIZE));
1234 		kaddr = block_ctx->datav[i];
1235 		memcpy(dst, kaddr + offset_in_page, cur);
1236 
1237 		dst += cur;
1238 		len -= cur;
1239 		offset_in_page = 0;
1240 		i++;
1241 	}
1242 }
1243 
1244 static int btrfsic_create_link_to_next_block(
1245 		struct btrfsic_state *state,
1246 		struct btrfsic_block *block,
1247 		struct btrfsic_block_data_ctx *block_ctx,
1248 		u64 next_bytenr,
1249 		int limit_nesting,
1250 		struct btrfsic_block_data_ctx *next_block_ctx,
1251 		struct btrfsic_block **next_blockp,
1252 		int force_iodone_flag,
1253 		int *num_copiesp, int *mirror_nump,
1254 		struct btrfs_disk_key *disk_key,
1255 		u64 parent_generation)
1256 {
1257 	struct btrfs_fs_info *fs_info = state->fs_info;
1258 	struct btrfsic_block *next_block = NULL;
1259 	int ret;
1260 	struct btrfsic_block_link *l;
1261 	int did_alloc_block_link;
1262 	int block_was_created;
1263 
1264 	*next_blockp = NULL;
1265 	if (0 == *num_copiesp) {
1266 		*num_copiesp = btrfs_num_copies(fs_info, next_bytenr,
1267 						state->metablock_size);
1268 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1269 			pr_info("num_copies(log_bytenr=%llu) = %d\n",
1270 			       next_bytenr, *num_copiesp);
1271 		*mirror_nump = 1;
1272 	}
1273 
1274 	if (*mirror_nump > *num_copiesp)
1275 		return 0;
1276 
1277 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1278 		pr_info("btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1279 		       *mirror_nump);
1280 	ret = btrfsic_map_block(state, next_bytenr,
1281 				state->metablock_size,
1282 				next_block_ctx, *mirror_nump);
1283 	if (ret) {
1284 		pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1285 		       next_bytenr, *mirror_nump);
1286 		btrfsic_release_block_ctx(next_block_ctx);
1287 		*next_blockp = NULL;
1288 		return -1;
1289 	}
1290 
1291 	next_block = btrfsic_block_lookup_or_add(state,
1292 						 next_block_ctx, "referenced ",
1293 						 1, force_iodone_flag,
1294 						 !force_iodone_flag,
1295 						 *mirror_nump,
1296 						 &block_was_created);
1297 	if (NULL == next_block) {
1298 		btrfsic_release_block_ctx(next_block_ctx);
1299 		*next_blockp = NULL;
1300 		return -1;
1301 	}
1302 	if (block_was_created) {
1303 		l = NULL;
1304 		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1305 	} else {
1306 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1307 			if (next_block->logical_bytenr != next_bytenr &&
1308 			    !(!next_block->is_metadata &&
1309 			      0 == next_block->logical_bytenr))
1310 				pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1311 				       next_bytenr, next_block_ctx->dev->name,
1312 				       next_block_ctx->dev_bytenr, *mirror_nump,
1313 				       btrfsic_get_block_type(state,
1314 							      next_block),
1315 				       next_block->logical_bytenr);
1316 			else
1317 				pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1318 				       next_bytenr, next_block_ctx->dev->name,
1319 				       next_block_ctx->dev_bytenr, *mirror_nump,
1320 				       btrfsic_get_block_type(state,
1321 							      next_block));
1322 		}
1323 		next_block->logical_bytenr = next_bytenr;
1324 
1325 		next_block->mirror_num = *mirror_nump;
1326 		l = btrfsic_block_link_hashtable_lookup(
1327 				next_block_ctx->dev->bdev,
1328 				next_block_ctx->dev_bytenr,
1329 				block_ctx->dev->bdev,
1330 				block_ctx->dev_bytenr,
1331 				&state->block_link_hashtable);
1332 	}
1333 
1334 	next_block->disk_key = *disk_key;
1335 	if (NULL == l) {
1336 		l = btrfsic_block_link_alloc();
1337 		if (NULL == l) {
1338 			pr_info("btrfsic: error, kmalloc failed!\n");
1339 			btrfsic_release_block_ctx(next_block_ctx);
1340 			*next_blockp = NULL;
1341 			return -1;
1342 		}
1343 
1344 		did_alloc_block_link = 1;
1345 		l->block_ref_to = next_block;
1346 		l->block_ref_from = block;
1347 		l->ref_cnt = 1;
1348 		l->parent_generation = parent_generation;
1349 
1350 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1351 			btrfsic_print_add_link(state, l);
1352 
1353 		list_add(&l->node_ref_to, &block->ref_to_list);
1354 		list_add(&l->node_ref_from, &next_block->ref_from_list);
1355 
1356 		btrfsic_block_link_hashtable_add(l,
1357 						 &state->block_link_hashtable);
1358 	} else {
1359 		did_alloc_block_link = 0;
1360 		if (0 == limit_nesting) {
1361 			l->ref_cnt++;
1362 			l->parent_generation = parent_generation;
1363 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1364 				btrfsic_print_add_link(state, l);
1365 		}
1366 	}
1367 
1368 	if (limit_nesting > 0 && did_alloc_block_link) {
1369 		ret = btrfsic_read_block(state, next_block_ctx);
1370 		if (ret < (int)next_block_ctx->len) {
1371 			pr_info("btrfsic: read block @logical %llu failed!\n",
1372 			       next_bytenr);
1373 			btrfsic_release_block_ctx(next_block_ctx);
1374 			*next_blockp = NULL;
1375 			return -1;
1376 		}
1377 
1378 		*next_blockp = next_block;
1379 	} else {
1380 		*next_blockp = NULL;
1381 	}
1382 	(*mirror_nump)++;
1383 
1384 	return 0;
1385 }
1386 
1387 static int btrfsic_handle_extent_data(
1388 		struct btrfsic_state *state,
1389 		struct btrfsic_block *block,
1390 		struct btrfsic_block_data_ctx *block_ctx,
1391 		u32 item_offset, int force_iodone_flag)
1392 {
1393 	struct btrfs_fs_info *fs_info = state->fs_info;
1394 	struct btrfs_file_extent_item file_extent_item;
1395 	u64 file_extent_item_offset;
1396 	u64 next_bytenr;
1397 	u64 num_bytes;
1398 	u64 generation;
1399 	struct btrfsic_block_link *l;
1400 	int ret;
1401 
1402 	file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1403 				  item_offset;
1404 	if (file_extent_item_offset +
1405 	    offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1406 	    block_ctx->len) {
1407 		pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1408 		       block_ctx->start, block_ctx->dev->name);
1409 		return -1;
1410 	}
1411 
1412 	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1413 		file_extent_item_offset,
1414 		offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1415 	if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1416 	    btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1417 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1418 			pr_info("extent_data: type %u, disk_bytenr = %llu\n",
1419 			       file_extent_item.type,
1420 			       btrfs_stack_file_extent_disk_bytenr(
1421 			       &file_extent_item));
1422 		return 0;
1423 	}
1424 
1425 	if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1426 	    block_ctx->len) {
1427 		pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1428 		       block_ctx->start, block_ctx->dev->name);
1429 		return -1;
1430 	}
1431 	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1432 				     file_extent_item_offset,
1433 				     sizeof(struct btrfs_file_extent_item));
1434 	next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1435 	if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1436 	    BTRFS_COMPRESS_NONE) {
1437 		next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1438 		num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1439 	} else {
1440 		num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1441 	}
1442 	generation = btrfs_stack_file_extent_generation(&file_extent_item);
1443 
1444 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1445 		pr_info("extent_data: type %u, disk_bytenr = %llu, offset = %llu, num_bytes = %llu\n",
1446 		       file_extent_item.type,
1447 		       btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1448 		       btrfs_stack_file_extent_offset(&file_extent_item),
1449 		       num_bytes);
1450 	while (num_bytes > 0) {
1451 		u32 chunk_len;
1452 		int num_copies;
1453 		int mirror_num;
1454 
1455 		if (num_bytes > state->datablock_size)
1456 			chunk_len = state->datablock_size;
1457 		else
1458 			chunk_len = num_bytes;
1459 
1460 		num_copies = btrfs_num_copies(fs_info, next_bytenr,
1461 					      state->datablock_size);
1462 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1463 			pr_info("num_copies(log_bytenr=%llu) = %d\n",
1464 			       next_bytenr, num_copies);
1465 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1466 			struct btrfsic_block_data_ctx next_block_ctx;
1467 			struct btrfsic_block *next_block;
1468 			int block_was_created;
1469 
1470 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1471 				pr_info("btrfsic_handle_extent_data(mirror_num=%d)\n",
1472 					mirror_num);
1473 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1474 				pr_info("\tdisk_bytenr = %llu, num_bytes %u\n",
1475 				       next_bytenr, chunk_len);
1476 			ret = btrfsic_map_block(state, next_bytenr,
1477 						chunk_len, &next_block_ctx,
1478 						mirror_num);
1479 			if (ret) {
1480 				pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1481 				       next_bytenr, mirror_num);
1482 				return -1;
1483 			}
1484 
1485 			next_block = btrfsic_block_lookup_or_add(
1486 					state,
1487 					&next_block_ctx,
1488 					"referenced ",
1489 					0,
1490 					force_iodone_flag,
1491 					!force_iodone_flag,
1492 					mirror_num,
1493 					&block_was_created);
1494 			if (NULL == next_block) {
1495 				pr_info("btrfsic: error, kmalloc failed!\n");
1496 				btrfsic_release_block_ctx(&next_block_ctx);
1497 				return -1;
1498 			}
1499 			if (!block_was_created) {
1500 				if ((state->print_mask &
1501 				     BTRFSIC_PRINT_MASK_VERBOSE) &&
1502 				    next_block->logical_bytenr != next_bytenr &&
1503 				    !(!next_block->is_metadata &&
1504 				      0 == next_block->logical_bytenr)) {
1505 					pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, D, bytenr mismatch (!= stored %llu).\n",
1506 					       next_bytenr,
1507 					       next_block_ctx.dev->name,
1508 					       next_block_ctx.dev_bytenr,
1509 					       mirror_num,
1510 					       next_block->logical_bytenr);
1511 				}
1512 				next_block->logical_bytenr = next_bytenr;
1513 				next_block->mirror_num = mirror_num;
1514 			}
1515 
1516 			l = btrfsic_block_link_lookup_or_add(state,
1517 							     &next_block_ctx,
1518 							     next_block, block,
1519 							     generation);
1520 			btrfsic_release_block_ctx(&next_block_ctx);
1521 			if (NULL == l)
1522 				return -1;
1523 		}
1524 
1525 		next_bytenr += chunk_len;
1526 		num_bytes -= chunk_len;
1527 	}
1528 
1529 	return 0;
1530 }
1531 
1532 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1533 			     struct btrfsic_block_data_ctx *block_ctx_out,
1534 			     int mirror_num)
1535 {
1536 	struct btrfs_fs_info *fs_info = state->fs_info;
1537 	int ret;
1538 	u64 length;
1539 	struct btrfs_bio *multi = NULL;
1540 	struct btrfs_device *device;
1541 
1542 	length = len;
1543 	ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
1544 			      bytenr, &length, &multi, mirror_num);
1545 
1546 	if (ret) {
1547 		block_ctx_out->start = 0;
1548 		block_ctx_out->dev_bytenr = 0;
1549 		block_ctx_out->len = 0;
1550 		block_ctx_out->dev = NULL;
1551 		block_ctx_out->datav = NULL;
1552 		block_ctx_out->pagev = NULL;
1553 		block_ctx_out->mem_to_free = NULL;
1554 
1555 		return ret;
1556 	}
1557 
1558 	device = multi->stripes[0].dev;
1559 	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1560 	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1561 	block_ctx_out->start = bytenr;
1562 	block_ctx_out->len = len;
1563 	block_ctx_out->datav = NULL;
1564 	block_ctx_out->pagev = NULL;
1565 	block_ctx_out->mem_to_free = NULL;
1566 
1567 	kfree(multi);
1568 	if (NULL == block_ctx_out->dev) {
1569 		ret = -ENXIO;
1570 		pr_info("btrfsic: error, cannot lookup dev (#1)!\n");
1571 	}
1572 
1573 	return ret;
1574 }
1575 
1576 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1577 {
1578 	if (block_ctx->mem_to_free) {
1579 		unsigned int num_pages;
1580 
1581 		BUG_ON(!block_ctx->datav);
1582 		BUG_ON(!block_ctx->pagev);
1583 		num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1584 			    PAGE_SHIFT;
1585 		while (num_pages > 0) {
1586 			num_pages--;
1587 			if (block_ctx->datav[num_pages]) {
1588 				kunmap(block_ctx->pagev[num_pages]);
1589 				block_ctx->datav[num_pages] = NULL;
1590 			}
1591 			if (block_ctx->pagev[num_pages]) {
1592 				__free_page(block_ctx->pagev[num_pages]);
1593 				block_ctx->pagev[num_pages] = NULL;
1594 			}
1595 		}
1596 
1597 		kfree(block_ctx->mem_to_free);
1598 		block_ctx->mem_to_free = NULL;
1599 		block_ctx->pagev = NULL;
1600 		block_ctx->datav = NULL;
1601 	}
1602 }
1603 
1604 static int btrfsic_read_block(struct btrfsic_state *state,
1605 			      struct btrfsic_block_data_ctx *block_ctx)
1606 {
1607 	unsigned int num_pages;
1608 	unsigned int i;
1609 	u64 dev_bytenr;
1610 	int ret;
1611 
1612 	BUG_ON(block_ctx->datav);
1613 	BUG_ON(block_ctx->pagev);
1614 	BUG_ON(block_ctx->mem_to_free);
1615 	if (block_ctx->dev_bytenr & ((u64)PAGE_SIZE - 1)) {
1616 		pr_info("btrfsic: read_block() with unaligned bytenr %llu\n",
1617 		       block_ctx->dev_bytenr);
1618 		return -1;
1619 	}
1620 
1621 	num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1622 		    PAGE_SHIFT;
1623 	block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1624 					  sizeof(*block_ctx->pagev)) *
1625 					 num_pages, GFP_NOFS);
1626 	if (!block_ctx->mem_to_free)
1627 		return -ENOMEM;
1628 	block_ctx->datav = block_ctx->mem_to_free;
1629 	block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1630 	for (i = 0; i < num_pages; i++) {
1631 		block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1632 		if (!block_ctx->pagev[i])
1633 			return -1;
1634 	}
1635 
1636 	dev_bytenr = block_ctx->dev_bytenr;
1637 	for (i = 0; i < num_pages;) {
1638 		struct bio *bio;
1639 		unsigned int j;
1640 
1641 		bio = btrfs_io_bio_alloc(num_pages - i);
1642 		bio->bi_bdev = block_ctx->dev->bdev;
1643 		bio->bi_iter.bi_sector = dev_bytenr >> 9;
1644 		bio_set_op_attrs(bio, REQ_OP_READ, 0);
1645 
1646 		for (j = i; j < num_pages; j++) {
1647 			ret = bio_add_page(bio, block_ctx->pagev[j],
1648 					   PAGE_SIZE, 0);
1649 			if (PAGE_SIZE != ret)
1650 				break;
1651 		}
1652 		if (j == i) {
1653 			pr_info("btrfsic: error, failed to add a single page!\n");
1654 			return -1;
1655 		}
1656 		if (submit_bio_wait(bio)) {
1657 			pr_info("btrfsic: read error at logical %llu dev %s!\n",
1658 			       block_ctx->start, block_ctx->dev->name);
1659 			bio_put(bio);
1660 			return -1;
1661 		}
1662 		bio_put(bio);
1663 		dev_bytenr += (j - i) * PAGE_SIZE;
1664 		i = j;
1665 	}
1666 	for (i = 0; i < num_pages; i++)
1667 		block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1668 
1669 	return block_ctx->len;
1670 }
1671 
1672 static void btrfsic_dump_database(struct btrfsic_state *state)
1673 {
1674 	const struct btrfsic_block *b_all;
1675 
1676 	BUG_ON(NULL == state);
1677 
1678 	pr_info("all_blocks_list:\n");
1679 	list_for_each_entry(b_all, &state->all_blocks_list, all_blocks_node) {
1680 		const struct btrfsic_block_link *l;
1681 
1682 		pr_info("%c-block @%llu (%s/%llu/%d)\n",
1683 		       btrfsic_get_block_type(state, b_all),
1684 		       b_all->logical_bytenr, b_all->dev_state->name,
1685 		       b_all->dev_bytenr, b_all->mirror_num);
1686 
1687 		list_for_each_entry(l, &b_all->ref_to_list, node_ref_to) {
1688 			pr_info(" %c @%llu (%s/%llu/%d) refers %u* to %c @%llu (%s/%llu/%d)\n",
1689 			       btrfsic_get_block_type(state, b_all),
1690 			       b_all->logical_bytenr, b_all->dev_state->name,
1691 			       b_all->dev_bytenr, b_all->mirror_num,
1692 			       l->ref_cnt,
1693 			       btrfsic_get_block_type(state, l->block_ref_to),
1694 			       l->block_ref_to->logical_bytenr,
1695 			       l->block_ref_to->dev_state->name,
1696 			       l->block_ref_to->dev_bytenr,
1697 			       l->block_ref_to->mirror_num);
1698 		}
1699 
1700 		list_for_each_entry(l, &b_all->ref_from_list, node_ref_from) {
1701 			pr_info(" %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
1702 			       btrfsic_get_block_type(state, b_all),
1703 			       b_all->logical_bytenr, b_all->dev_state->name,
1704 			       b_all->dev_bytenr, b_all->mirror_num,
1705 			       l->ref_cnt,
1706 			       btrfsic_get_block_type(state, l->block_ref_from),
1707 			       l->block_ref_from->logical_bytenr,
1708 			       l->block_ref_from->dev_state->name,
1709 			       l->block_ref_from->dev_bytenr,
1710 			       l->block_ref_from->mirror_num);
1711 		}
1712 
1713 		pr_info("\n");
1714 	}
1715 }
1716 
1717 /*
1718  * Test whether the disk block contains a tree block (leaf or node)
1719  * (note that this test fails for the super block)
1720  */
1721 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1722 				     char **datav, unsigned int num_pages)
1723 {
1724 	struct btrfs_fs_info *fs_info = state->fs_info;
1725 	struct btrfs_header *h;
1726 	u8 csum[BTRFS_CSUM_SIZE];
1727 	u32 crc = ~(u32)0;
1728 	unsigned int i;
1729 
1730 	if (num_pages * PAGE_SIZE < state->metablock_size)
1731 		return 1; /* not metadata */
1732 	num_pages = state->metablock_size >> PAGE_SHIFT;
1733 	h = (struct btrfs_header *)datav[0];
1734 
1735 	if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1736 		return 1;
1737 
1738 	for (i = 0; i < num_pages; i++) {
1739 		u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1740 		size_t sublen = i ? PAGE_SIZE :
1741 				    (PAGE_SIZE - BTRFS_CSUM_SIZE);
1742 
1743 		crc = btrfs_crc32c(crc, data, sublen);
1744 	}
1745 	btrfs_csum_final(crc, csum);
1746 	if (memcmp(csum, h->csum, state->csum_size))
1747 		return 1;
1748 
1749 	return 0; /* is metadata */
1750 }
1751 
1752 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1753 					  u64 dev_bytenr, char **mapped_datav,
1754 					  unsigned int num_pages,
1755 					  struct bio *bio, int *bio_is_patched,
1756 					  struct buffer_head *bh,
1757 					  int submit_bio_bh_rw)
1758 {
1759 	int is_metadata;
1760 	struct btrfsic_block *block;
1761 	struct btrfsic_block_data_ctx block_ctx;
1762 	int ret;
1763 	struct btrfsic_state *state = dev_state->state;
1764 	struct block_device *bdev = dev_state->bdev;
1765 	unsigned int processed_len;
1766 
1767 	if (NULL != bio_is_patched)
1768 		*bio_is_patched = 0;
1769 
1770 again:
1771 	if (num_pages == 0)
1772 		return;
1773 
1774 	processed_len = 0;
1775 	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1776 						      num_pages));
1777 
1778 	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1779 					       &state->block_hashtable);
1780 	if (NULL != block) {
1781 		u64 bytenr = 0;
1782 		struct btrfsic_block_link *l, *tmp;
1783 
1784 		if (block->is_superblock) {
1785 			bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1786 						    mapped_datav[0]);
1787 			if (num_pages * PAGE_SIZE <
1788 			    BTRFS_SUPER_INFO_SIZE) {
1789 				pr_info("btrfsic: cannot work with too short bios!\n");
1790 				return;
1791 			}
1792 			is_metadata = 1;
1793 			BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_SIZE - 1));
1794 			processed_len = BTRFS_SUPER_INFO_SIZE;
1795 			if (state->print_mask &
1796 			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1797 				pr_info("[before new superblock is written]:\n");
1798 				btrfsic_dump_tree_sub(state, block, 0);
1799 			}
1800 		}
1801 		if (is_metadata) {
1802 			if (!block->is_superblock) {
1803 				if (num_pages * PAGE_SIZE <
1804 				    state->metablock_size) {
1805 					pr_info("btrfsic: cannot work with too short bios!\n");
1806 					return;
1807 				}
1808 				processed_len = state->metablock_size;
1809 				bytenr = btrfs_stack_header_bytenr(
1810 						(struct btrfs_header *)
1811 						mapped_datav[0]);
1812 				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1813 							       dev_state,
1814 							       dev_bytenr);
1815 			}
1816 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1817 				if (block->logical_bytenr != bytenr &&
1818 				    !(!block->is_metadata &&
1819 				      block->logical_bytenr == 0))
1820 					pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1821 					       bytenr, dev_state->name,
1822 					       dev_bytenr,
1823 					       block->mirror_num,
1824 					       btrfsic_get_block_type(state,
1825 								      block),
1826 					       block->logical_bytenr);
1827 				else
1828 					pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1829 					       bytenr, dev_state->name,
1830 					       dev_bytenr, block->mirror_num,
1831 					       btrfsic_get_block_type(state,
1832 								      block));
1833 			}
1834 			block->logical_bytenr = bytenr;
1835 		} else {
1836 			if (num_pages * PAGE_SIZE <
1837 			    state->datablock_size) {
1838 				pr_info("btrfsic: cannot work with too short bios!\n");
1839 				return;
1840 			}
1841 			processed_len = state->datablock_size;
1842 			bytenr = block->logical_bytenr;
1843 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1844 				pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1845 				       bytenr, dev_state->name, dev_bytenr,
1846 				       block->mirror_num,
1847 				       btrfsic_get_block_type(state, block));
1848 		}
1849 
1850 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1851 			pr_info("ref_to_list: %cE, ref_from_list: %cE\n",
1852 			       list_empty(&block->ref_to_list) ? ' ' : '!',
1853 			       list_empty(&block->ref_from_list) ? ' ' : '!');
1854 		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1855 			pr_info("btrfs: attempt to overwrite %c-block @%llu (%s/%llu/%d), old(gen=%llu, objectid=%llu, type=%d, offset=%llu), new(gen=%llu), which is referenced by most recent superblock (superblockgen=%llu)!\n",
1856 			       btrfsic_get_block_type(state, block), bytenr,
1857 			       dev_state->name, dev_bytenr, block->mirror_num,
1858 			       block->generation,
1859 			       btrfs_disk_key_objectid(&block->disk_key),
1860 			       block->disk_key.type,
1861 			       btrfs_disk_key_offset(&block->disk_key),
1862 			       btrfs_stack_header_generation(
1863 				       (struct btrfs_header *) mapped_datav[0]),
1864 			       state->max_superblock_generation);
1865 			btrfsic_dump_tree(state);
1866 		}
1867 
1868 		if (!block->is_iodone && !block->never_written) {
1869 			pr_info("btrfs: attempt to overwrite %c-block @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu, which is not yet iodone!\n",
1870 			       btrfsic_get_block_type(state, block), bytenr,
1871 			       dev_state->name, dev_bytenr, block->mirror_num,
1872 			       block->generation,
1873 			       btrfs_stack_header_generation(
1874 				       (struct btrfs_header *)
1875 				       mapped_datav[0]));
1876 			/* it would not be safe to go on */
1877 			btrfsic_dump_tree(state);
1878 			goto continue_loop;
1879 		}
1880 
1881 		/*
1882 		 * Clear all references of this block. Do not free
1883 		 * the block itself even if is not referenced anymore
1884 		 * because it still carries valuable information
1885 		 * like whether it was ever written and IO completed.
1886 		 */
1887 		list_for_each_entry_safe(l, tmp, &block->ref_to_list,
1888 					 node_ref_to) {
1889 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1890 				btrfsic_print_rem_link(state, l);
1891 			l->ref_cnt--;
1892 			if (0 == l->ref_cnt) {
1893 				list_del(&l->node_ref_to);
1894 				list_del(&l->node_ref_from);
1895 				btrfsic_block_link_hashtable_remove(l);
1896 				btrfsic_block_link_free(l);
1897 			}
1898 		}
1899 
1900 		block_ctx.dev = dev_state;
1901 		block_ctx.dev_bytenr = dev_bytenr;
1902 		block_ctx.start = bytenr;
1903 		block_ctx.len = processed_len;
1904 		block_ctx.pagev = NULL;
1905 		block_ctx.mem_to_free = NULL;
1906 		block_ctx.datav = mapped_datav;
1907 
1908 		if (is_metadata || state->include_extent_data) {
1909 			block->never_written = 0;
1910 			block->iodone_w_error = 0;
1911 			if (NULL != bio) {
1912 				block->is_iodone = 0;
1913 				BUG_ON(NULL == bio_is_patched);
1914 				if (!*bio_is_patched) {
1915 					block->orig_bio_bh_private =
1916 					    bio->bi_private;
1917 					block->orig_bio_bh_end_io.bio =
1918 					    bio->bi_end_io;
1919 					block->next_in_same_bio = NULL;
1920 					bio->bi_private = block;
1921 					bio->bi_end_io = btrfsic_bio_end_io;
1922 					*bio_is_patched = 1;
1923 				} else {
1924 					struct btrfsic_block *chained_block =
1925 					    (struct btrfsic_block *)
1926 					    bio->bi_private;
1927 
1928 					BUG_ON(NULL == chained_block);
1929 					block->orig_bio_bh_private =
1930 					    chained_block->orig_bio_bh_private;
1931 					block->orig_bio_bh_end_io.bio =
1932 					    chained_block->orig_bio_bh_end_io.
1933 					    bio;
1934 					block->next_in_same_bio = chained_block;
1935 					bio->bi_private = block;
1936 				}
1937 			} else if (NULL != bh) {
1938 				block->is_iodone = 0;
1939 				block->orig_bio_bh_private = bh->b_private;
1940 				block->orig_bio_bh_end_io.bh = bh->b_end_io;
1941 				block->next_in_same_bio = NULL;
1942 				bh->b_private = block;
1943 				bh->b_end_io = btrfsic_bh_end_io;
1944 			} else {
1945 				block->is_iodone = 1;
1946 				block->orig_bio_bh_private = NULL;
1947 				block->orig_bio_bh_end_io.bio = NULL;
1948 				block->next_in_same_bio = NULL;
1949 			}
1950 		}
1951 
1952 		block->flush_gen = dev_state->last_flush_gen + 1;
1953 		block->submit_bio_bh_rw = submit_bio_bh_rw;
1954 		if (is_metadata) {
1955 			block->logical_bytenr = bytenr;
1956 			block->is_metadata = 1;
1957 			if (block->is_superblock) {
1958 				BUG_ON(PAGE_SIZE !=
1959 				       BTRFS_SUPER_INFO_SIZE);
1960 				ret = btrfsic_process_written_superblock(
1961 						state,
1962 						block,
1963 						(struct btrfs_super_block *)
1964 						mapped_datav[0]);
1965 				if (state->print_mask &
1966 				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
1967 					pr_info("[after new superblock is written]:\n");
1968 					btrfsic_dump_tree_sub(state, block, 0);
1969 				}
1970 			} else {
1971 				block->mirror_num = 0;	/* unknown */
1972 				ret = btrfsic_process_metablock(
1973 						state,
1974 						block,
1975 						&block_ctx,
1976 						0, 0);
1977 			}
1978 			if (ret)
1979 				pr_info("btrfsic: btrfsic_process_metablock(root @%llu) failed!\n",
1980 				       dev_bytenr);
1981 		} else {
1982 			block->is_metadata = 0;
1983 			block->mirror_num = 0;	/* unknown */
1984 			block->generation = BTRFSIC_GENERATION_UNKNOWN;
1985 			if (!state->include_extent_data
1986 			    && list_empty(&block->ref_from_list)) {
1987 				/*
1988 				 * disk block is overwritten with extent
1989 				 * data (not meta data) and we are configured
1990 				 * to not include extent data: take the
1991 				 * chance and free the block's memory
1992 				 */
1993 				btrfsic_block_hashtable_remove(block);
1994 				list_del(&block->all_blocks_node);
1995 				btrfsic_block_free(block);
1996 			}
1997 		}
1998 		btrfsic_release_block_ctx(&block_ctx);
1999 	} else {
2000 		/* block has not been found in hash table */
2001 		u64 bytenr;
2002 
2003 		if (!is_metadata) {
2004 			processed_len = state->datablock_size;
2005 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2006 				pr_info("Written block (%s/%llu/?) !found in hash table, D.\n",
2007 				       dev_state->name, dev_bytenr);
2008 			if (!state->include_extent_data) {
2009 				/* ignore that written D block */
2010 				goto continue_loop;
2011 			}
2012 
2013 			/* this is getting ugly for the
2014 			 * include_extent_data case... */
2015 			bytenr = 0;	/* unknown */
2016 		} else {
2017 			processed_len = state->metablock_size;
2018 			bytenr = btrfs_stack_header_bytenr(
2019 					(struct btrfs_header *)
2020 					mapped_datav[0]);
2021 			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2022 						       dev_bytenr);
2023 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2024 				pr_info("Written block @%llu (%s/%llu/?) !found in hash table, M.\n",
2025 				       bytenr, dev_state->name, dev_bytenr);
2026 		}
2027 
2028 		block_ctx.dev = dev_state;
2029 		block_ctx.dev_bytenr = dev_bytenr;
2030 		block_ctx.start = bytenr;
2031 		block_ctx.len = processed_len;
2032 		block_ctx.pagev = NULL;
2033 		block_ctx.mem_to_free = NULL;
2034 		block_ctx.datav = mapped_datav;
2035 
2036 		block = btrfsic_block_alloc();
2037 		if (NULL == block) {
2038 			pr_info("btrfsic: error, kmalloc failed!\n");
2039 			btrfsic_release_block_ctx(&block_ctx);
2040 			goto continue_loop;
2041 		}
2042 		block->dev_state = dev_state;
2043 		block->dev_bytenr = dev_bytenr;
2044 		block->logical_bytenr = bytenr;
2045 		block->is_metadata = is_metadata;
2046 		block->never_written = 0;
2047 		block->iodone_w_error = 0;
2048 		block->mirror_num = 0;	/* unknown */
2049 		block->flush_gen = dev_state->last_flush_gen + 1;
2050 		block->submit_bio_bh_rw = submit_bio_bh_rw;
2051 		if (NULL != bio) {
2052 			block->is_iodone = 0;
2053 			BUG_ON(NULL == bio_is_patched);
2054 			if (!*bio_is_patched) {
2055 				block->orig_bio_bh_private = bio->bi_private;
2056 				block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2057 				block->next_in_same_bio = NULL;
2058 				bio->bi_private = block;
2059 				bio->bi_end_io = btrfsic_bio_end_io;
2060 				*bio_is_patched = 1;
2061 			} else {
2062 				struct btrfsic_block *chained_block =
2063 				    (struct btrfsic_block *)
2064 				    bio->bi_private;
2065 
2066 				BUG_ON(NULL == chained_block);
2067 				block->orig_bio_bh_private =
2068 				    chained_block->orig_bio_bh_private;
2069 				block->orig_bio_bh_end_io.bio =
2070 				    chained_block->orig_bio_bh_end_io.bio;
2071 				block->next_in_same_bio = chained_block;
2072 				bio->bi_private = block;
2073 			}
2074 		} else if (NULL != bh) {
2075 			block->is_iodone = 0;
2076 			block->orig_bio_bh_private = bh->b_private;
2077 			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2078 			block->next_in_same_bio = NULL;
2079 			bh->b_private = block;
2080 			bh->b_end_io = btrfsic_bh_end_io;
2081 		} else {
2082 			block->is_iodone = 1;
2083 			block->orig_bio_bh_private = NULL;
2084 			block->orig_bio_bh_end_io.bio = NULL;
2085 			block->next_in_same_bio = NULL;
2086 		}
2087 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2088 			pr_info("New written %c-block @%llu (%s/%llu/%d)\n",
2089 			       is_metadata ? 'M' : 'D',
2090 			       block->logical_bytenr, block->dev_state->name,
2091 			       block->dev_bytenr, block->mirror_num);
2092 		list_add(&block->all_blocks_node, &state->all_blocks_list);
2093 		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2094 
2095 		if (is_metadata) {
2096 			ret = btrfsic_process_metablock(state, block,
2097 							&block_ctx, 0, 0);
2098 			if (ret)
2099 				pr_info("btrfsic: process_metablock(root @%llu) failed!\n",
2100 				       dev_bytenr);
2101 		}
2102 		btrfsic_release_block_ctx(&block_ctx);
2103 	}
2104 
2105 continue_loop:
2106 	BUG_ON(!processed_len);
2107 	dev_bytenr += processed_len;
2108 	mapped_datav += processed_len >> PAGE_SHIFT;
2109 	num_pages -= processed_len >> PAGE_SHIFT;
2110 	goto again;
2111 }
2112 
2113 static void btrfsic_bio_end_io(struct bio *bp)
2114 {
2115 	struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2116 	int iodone_w_error;
2117 
2118 	/* mutex is not held! This is not save if IO is not yet completed
2119 	 * on umount */
2120 	iodone_w_error = 0;
2121 	if (bp->bi_status)
2122 		iodone_w_error = 1;
2123 
2124 	BUG_ON(NULL == block);
2125 	bp->bi_private = block->orig_bio_bh_private;
2126 	bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2127 
2128 	do {
2129 		struct btrfsic_block *next_block;
2130 		struct btrfsic_dev_state *const dev_state = block->dev_state;
2131 
2132 		if ((dev_state->state->print_mask &
2133 		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2134 			pr_info("bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2135 			       bp->bi_status,
2136 			       btrfsic_get_block_type(dev_state->state, block),
2137 			       block->logical_bytenr, dev_state->name,
2138 			       block->dev_bytenr, block->mirror_num);
2139 		next_block = block->next_in_same_bio;
2140 		block->iodone_w_error = iodone_w_error;
2141 		if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2142 			dev_state->last_flush_gen++;
2143 			if ((dev_state->state->print_mask &
2144 			     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2145 				pr_info("bio_end_io() new %s flush_gen=%llu\n",
2146 				       dev_state->name,
2147 				       dev_state->last_flush_gen);
2148 		}
2149 		if (block->submit_bio_bh_rw & REQ_FUA)
2150 			block->flush_gen = 0; /* FUA completed means block is
2151 					       * on disk */
2152 		block->is_iodone = 1; /* for FLUSH, this releases the block */
2153 		block = next_block;
2154 	} while (NULL != block);
2155 
2156 	bp->bi_end_io(bp);
2157 }
2158 
2159 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2160 {
2161 	struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2162 	int iodone_w_error = !uptodate;
2163 	struct btrfsic_dev_state *dev_state;
2164 
2165 	BUG_ON(NULL == block);
2166 	dev_state = block->dev_state;
2167 	if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2168 		pr_info("bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2169 		       iodone_w_error,
2170 		       btrfsic_get_block_type(dev_state->state, block),
2171 		       block->logical_bytenr, block->dev_state->name,
2172 		       block->dev_bytenr, block->mirror_num);
2173 
2174 	block->iodone_w_error = iodone_w_error;
2175 	if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2176 		dev_state->last_flush_gen++;
2177 		if ((dev_state->state->print_mask &
2178 		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2179 			pr_info("bh_end_io() new %s flush_gen=%llu\n",
2180 			       dev_state->name, dev_state->last_flush_gen);
2181 	}
2182 	if (block->submit_bio_bh_rw & REQ_FUA)
2183 		block->flush_gen = 0; /* FUA completed means block is on disk */
2184 
2185 	bh->b_private = block->orig_bio_bh_private;
2186 	bh->b_end_io = block->orig_bio_bh_end_io.bh;
2187 	block->is_iodone = 1; /* for FLUSH, this releases the block */
2188 	bh->b_end_io(bh, uptodate);
2189 }
2190 
2191 static int btrfsic_process_written_superblock(
2192 		struct btrfsic_state *state,
2193 		struct btrfsic_block *const superblock,
2194 		struct btrfs_super_block *const super_hdr)
2195 {
2196 	struct btrfs_fs_info *fs_info = state->fs_info;
2197 	int pass;
2198 
2199 	superblock->generation = btrfs_super_generation(super_hdr);
2200 	if (!(superblock->generation > state->max_superblock_generation ||
2201 	      0 == state->max_superblock_generation)) {
2202 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2203 			pr_info("btrfsic: superblock @%llu (%s/%llu/%d) with old gen %llu <= %llu\n",
2204 			       superblock->logical_bytenr,
2205 			       superblock->dev_state->name,
2206 			       superblock->dev_bytenr, superblock->mirror_num,
2207 			       btrfs_super_generation(super_hdr),
2208 			       state->max_superblock_generation);
2209 	} else {
2210 		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2211 			pr_info("btrfsic: got new superblock @%llu (%s/%llu/%d) with new gen %llu > %llu\n",
2212 			       superblock->logical_bytenr,
2213 			       superblock->dev_state->name,
2214 			       superblock->dev_bytenr, superblock->mirror_num,
2215 			       btrfs_super_generation(super_hdr),
2216 			       state->max_superblock_generation);
2217 
2218 		state->max_superblock_generation =
2219 		    btrfs_super_generation(super_hdr);
2220 		state->latest_superblock = superblock;
2221 	}
2222 
2223 	for (pass = 0; pass < 3; pass++) {
2224 		int ret;
2225 		u64 next_bytenr;
2226 		struct btrfsic_block *next_block;
2227 		struct btrfsic_block_data_ctx tmp_next_block_ctx;
2228 		struct btrfsic_block_link *l;
2229 		int num_copies;
2230 		int mirror_num;
2231 		const char *additional_string = NULL;
2232 		struct btrfs_disk_key tmp_disk_key = {0};
2233 
2234 		btrfs_set_disk_key_objectid(&tmp_disk_key,
2235 					    BTRFS_ROOT_ITEM_KEY);
2236 		btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2237 
2238 		switch (pass) {
2239 		case 0:
2240 			btrfs_set_disk_key_objectid(&tmp_disk_key,
2241 						    BTRFS_ROOT_TREE_OBJECTID);
2242 			additional_string = "root ";
2243 			next_bytenr = btrfs_super_root(super_hdr);
2244 			if (state->print_mask &
2245 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2246 				pr_info("root@%llu\n", next_bytenr);
2247 			break;
2248 		case 1:
2249 			btrfs_set_disk_key_objectid(&tmp_disk_key,
2250 						    BTRFS_CHUNK_TREE_OBJECTID);
2251 			additional_string = "chunk ";
2252 			next_bytenr = btrfs_super_chunk_root(super_hdr);
2253 			if (state->print_mask &
2254 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2255 				pr_info("chunk@%llu\n", next_bytenr);
2256 			break;
2257 		case 2:
2258 			btrfs_set_disk_key_objectid(&tmp_disk_key,
2259 						    BTRFS_TREE_LOG_OBJECTID);
2260 			additional_string = "log ";
2261 			next_bytenr = btrfs_super_log_root(super_hdr);
2262 			if (0 == next_bytenr)
2263 				continue;
2264 			if (state->print_mask &
2265 			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2266 				pr_info("log@%llu\n", next_bytenr);
2267 			break;
2268 		}
2269 
2270 		num_copies = btrfs_num_copies(fs_info, next_bytenr,
2271 					      BTRFS_SUPER_INFO_SIZE);
2272 		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2273 			pr_info("num_copies(log_bytenr=%llu) = %d\n",
2274 			       next_bytenr, num_copies);
2275 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2276 			int was_created;
2277 
2278 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2279 				pr_info("btrfsic_process_written_superblock(mirror_num=%d)\n", mirror_num);
2280 			ret = btrfsic_map_block(state, next_bytenr,
2281 						BTRFS_SUPER_INFO_SIZE,
2282 						&tmp_next_block_ctx,
2283 						mirror_num);
2284 			if (ret) {
2285 				pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
2286 				       next_bytenr, mirror_num);
2287 				return -1;
2288 			}
2289 
2290 			next_block = btrfsic_block_lookup_or_add(
2291 					state,
2292 					&tmp_next_block_ctx,
2293 					additional_string,
2294 					1, 0, 1,
2295 					mirror_num,
2296 					&was_created);
2297 			if (NULL == next_block) {
2298 				pr_info("btrfsic: error, kmalloc failed!\n");
2299 				btrfsic_release_block_ctx(&tmp_next_block_ctx);
2300 				return -1;
2301 			}
2302 
2303 			next_block->disk_key = tmp_disk_key;
2304 			if (was_created)
2305 				next_block->generation =
2306 				    BTRFSIC_GENERATION_UNKNOWN;
2307 			l = btrfsic_block_link_lookup_or_add(
2308 					state,
2309 					&tmp_next_block_ctx,
2310 					next_block,
2311 					superblock,
2312 					BTRFSIC_GENERATION_UNKNOWN);
2313 			btrfsic_release_block_ctx(&tmp_next_block_ctx);
2314 			if (NULL == l)
2315 				return -1;
2316 		}
2317 	}
2318 
2319 	if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2320 		btrfsic_dump_tree(state);
2321 
2322 	return 0;
2323 }
2324 
2325 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2326 					struct btrfsic_block *const block,
2327 					int recursion_level)
2328 {
2329 	const struct btrfsic_block_link *l;
2330 	int ret = 0;
2331 
2332 	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2333 		/*
2334 		 * Note that this situation can happen and does not
2335 		 * indicate an error in regular cases. It happens
2336 		 * when disk blocks are freed and later reused.
2337 		 * The check-integrity module is not aware of any
2338 		 * block free operations, it just recognizes block
2339 		 * write operations. Therefore it keeps the linkage
2340 		 * information for a block until a block is
2341 		 * rewritten. This can temporarily cause incorrect
2342 		 * and even circular linkage informations. This
2343 		 * causes no harm unless such blocks are referenced
2344 		 * by the most recent super block.
2345 		 */
2346 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2347 			pr_info("btrfsic: abort cyclic linkage (case 1).\n");
2348 
2349 		return ret;
2350 	}
2351 
2352 	/*
2353 	 * This algorithm is recursive because the amount of used stack
2354 	 * space is very small and the max recursion depth is limited.
2355 	 */
2356 	list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2357 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2358 			pr_info("rl=%d, %c @%llu (%s/%llu/%d) %u* refers to %c @%llu (%s/%llu/%d)\n",
2359 			       recursion_level,
2360 			       btrfsic_get_block_type(state, block),
2361 			       block->logical_bytenr, block->dev_state->name,
2362 			       block->dev_bytenr, block->mirror_num,
2363 			       l->ref_cnt,
2364 			       btrfsic_get_block_type(state, l->block_ref_to),
2365 			       l->block_ref_to->logical_bytenr,
2366 			       l->block_ref_to->dev_state->name,
2367 			       l->block_ref_to->dev_bytenr,
2368 			       l->block_ref_to->mirror_num);
2369 		if (l->block_ref_to->never_written) {
2370 			pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is never written!\n",
2371 			       btrfsic_get_block_type(state, l->block_ref_to),
2372 			       l->block_ref_to->logical_bytenr,
2373 			       l->block_ref_to->dev_state->name,
2374 			       l->block_ref_to->dev_bytenr,
2375 			       l->block_ref_to->mirror_num);
2376 			ret = -1;
2377 		} else if (!l->block_ref_to->is_iodone) {
2378 			pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is not yet iodone!\n",
2379 			       btrfsic_get_block_type(state, l->block_ref_to),
2380 			       l->block_ref_to->logical_bytenr,
2381 			       l->block_ref_to->dev_state->name,
2382 			       l->block_ref_to->dev_bytenr,
2383 			       l->block_ref_to->mirror_num);
2384 			ret = -1;
2385 		} else if (l->block_ref_to->iodone_w_error) {
2386 			pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which has write error!\n",
2387 			       btrfsic_get_block_type(state, l->block_ref_to),
2388 			       l->block_ref_to->logical_bytenr,
2389 			       l->block_ref_to->dev_state->name,
2390 			       l->block_ref_to->dev_bytenr,
2391 			       l->block_ref_to->mirror_num);
2392 			ret = -1;
2393 		} else if (l->parent_generation !=
2394 			   l->block_ref_to->generation &&
2395 			   BTRFSIC_GENERATION_UNKNOWN !=
2396 			   l->parent_generation &&
2397 			   BTRFSIC_GENERATION_UNKNOWN !=
2398 			   l->block_ref_to->generation) {
2399 			pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) with generation %llu != parent generation %llu!\n",
2400 			       btrfsic_get_block_type(state, l->block_ref_to),
2401 			       l->block_ref_to->logical_bytenr,
2402 			       l->block_ref_to->dev_state->name,
2403 			       l->block_ref_to->dev_bytenr,
2404 			       l->block_ref_to->mirror_num,
2405 			       l->block_ref_to->generation,
2406 			       l->parent_generation);
2407 			ret = -1;
2408 		} else if (l->block_ref_to->flush_gen >
2409 			   l->block_ref_to->dev_state->last_flush_gen) {
2410 			pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is not flushed out of disk's write cache (block flush_gen=%llu, dev->flush_gen=%llu)!\n",
2411 			       btrfsic_get_block_type(state, l->block_ref_to),
2412 			       l->block_ref_to->logical_bytenr,
2413 			       l->block_ref_to->dev_state->name,
2414 			       l->block_ref_to->dev_bytenr,
2415 			       l->block_ref_to->mirror_num, block->flush_gen,
2416 			       l->block_ref_to->dev_state->last_flush_gen);
2417 			ret = -1;
2418 		} else if (-1 == btrfsic_check_all_ref_blocks(state,
2419 							      l->block_ref_to,
2420 							      recursion_level +
2421 							      1)) {
2422 			ret = -1;
2423 		}
2424 	}
2425 
2426 	return ret;
2427 }
2428 
2429 static int btrfsic_is_block_ref_by_superblock(
2430 		const struct btrfsic_state *state,
2431 		const struct btrfsic_block *block,
2432 		int recursion_level)
2433 {
2434 	const struct btrfsic_block_link *l;
2435 
2436 	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2437 		/* refer to comment at "abort cyclic linkage (case 1)" */
2438 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2439 			pr_info("btrfsic: abort cyclic linkage (case 2).\n");
2440 
2441 		return 0;
2442 	}
2443 
2444 	/*
2445 	 * This algorithm is recursive because the amount of used stack space
2446 	 * is very small and the max recursion depth is limited.
2447 	 */
2448 	list_for_each_entry(l, &block->ref_from_list, node_ref_from) {
2449 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2450 			pr_info("rl=%d, %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
2451 			       recursion_level,
2452 			       btrfsic_get_block_type(state, block),
2453 			       block->logical_bytenr, block->dev_state->name,
2454 			       block->dev_bytenr, block->mirror_num,
2455 			       l->ref_cnt,
2456 			       btrfsic_get_block_type(state, l->block_ref_from),
2457 			       l->block_ref_from->logical_bytenr,
2458 			       l->block_ref_from->dev_state->name,
2459 			       l->block_ref_from->dev_bytenr,
2460 			       l->block_ref_from->mirror_num);
2461 		if (l->block_ref_from->is_superblock &&
2462 		    state->latest_superblock->dev_bytenr ==
2463 		    l->block_ref_from->dev_bytenr &&
2464 		    state->latest_superblock->dev_state->bdev ==
2465 		    l->block_ref_from->dev_state->bdev)
2466 			return 1;
2467 		else if (btrfsic_is_block_ref_by_superblock(state,
2468 							    l->block_ref_from,
2469 							    recursion_level +
2470 							    1))
2471 			return 1;
2472 	}
2473 
2474 	return 0;
2475 }
2476 
2477 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2478 				   const struct btrfsic_block_link *l)
2479 {
2480 	pr_info("Add %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2481 	       l->ref_cnt,
2482 	       btrfsic_get_block_type(state, l->block_ref_from),
2483 	       l->block_ref_from->logical_bytenr,
2484 	       l->block_ref_from->dev_state->name,
2485 	       l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2486 	       btrfsic_get_block_type(state, l->block_ref_to),
2487 	       l->block_ref_to->logical_bytenr,
2488 	       l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2489 	       l->block_ref_to->mirror_num);
2490 }
2491 
2492 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2493 				   const struct btrfsic_block_link *l)
2494 {
2495 	pr_info("Rem %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2496 	       l->ref_cnt,
2497 	       btrfsic_get_block_type(state, l->block_ref_from),
2498 	       l->block_ref_from->logical_bytenr,
2499 	       l->block_ref_from->dev_state->name,
2500 	       l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2501 	       btrfsic_get_block_type(state, l->block_ref_to),
2502 	       l->block_ref_to->logical_bytenr,
2503 	       l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2504 	       l->block_ref_to->mirror_num);
2505 }
2506 
2507 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2508 				   const struct btrfsic_block *block)
2509 {
2510 	if (block->is_superblock &&
2511 	    state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2512 	    state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2513 		return 'S';
2514 	else if (block->is_superblock)
2515 		return 's';
2516 	else if (block->is_metadata)
2517 		return 'M';
2518 	else
2519 		return 'D';
2520 }
2521 
2522 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2523 {
2524 	btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2525 }
2526 
2527 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2528 				  const struct btrfsic_block *block,
2529 				  int indent_level)
2530 {
2531 	const struct btrfsic_block_link *l;
2532 	int indent_add;
2533 	static char buf[80];
2534 	int cursor_position;
2535 
2536 	/*
2537 	 * Should better fill an on-stack buffer with a complete line and
2538 	 * dump it at once when it is time to print a newline character.
2539 	 */
2540 
2541 	/*
2542 	 * This algorithm is recursive because the amount of used stack space
2543 	 * is very small and the max recursion depth is limited.
2544 	 */
2545 	indent_add = sprintf(buf, "%c-%llu(%s/%llu/%u)",
2546 			     btrfsic_get_block_type(state, block),
2547 			     block->logical_bytenr, block->dev_state->name,
2548 			     block->dev_bytenr, block->mirror_num);
2549 	if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2550 		printk("[...]\n");
2551 		return;
2552 	}
2553 	printk(buf);
2554 	indent_level += indent_add;
2555 	if (list_empty(&block->ref_to_list)) {
2556 		printk("\n");
2557 		return;
2558 	}
2559 	if (block->mirror_num > 1 &&
2560 	    !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2561 		printk(" [...]\n");
2562 		return;
2563 	}
2564 
2565 	cursor_position = indent_level;
2566 	list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2567 		while (cursor_position < indent_level) {
2568 			printk(" ");
2569 			cursor_position++;
2570 		}
2571 		if (l->ref_cnt > 1)
2572 			indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2573 		else
2574 			indent_add = sprintf(buf, " --> ");
2575 		if (indent_level + indent_add >
2576 		    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2577 			printk("[...]\n");
2578 			cursor_position = 0;
2579 			continue;
2580 		}
2581 
2582 		printk(buf);
2583 
2584 		btrfsic_dump_tree_sub(state, l->block_ref_to,
2585 				      indent_level + indent_add);
2586 		cursor_position = 0;
2587 	}
2588 }
2589 
2590 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2591 		struct btrfsic_state *state,
2592 		struct btrfsic_block_data_ctx *next_block_ctx,
2593 		struct btrfsic_block *next_block,
2594 		struct btrfsic_block *from_block,
2595 		u64 parent_generation)
2596 {
2597 	struct btrfsic_block_link *l;
2598 
2599 	l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2600 						next_block_ctx->dev_bytenr,
2601 						from_block->dev_state->bdev,
2602 						from_block->dev_bytenr,
2603 						&state->block_link_hashtable);
2604 	if (NULL == l) {
2605 		l = btrfsic_block_link_alloc();
2606 		if (NULL == l) {
2607 			pr_info("btrfsic: error, kmalloc failed!\n");
2608 			return NULL;
2609 		}
2610 
2611 		l->block_ref_to = next_block;
2612 		l->block_ref_from = from_block;
2613 		l->ref_cnt = 1;
2614 		l->parent_generation = parent_generation;
2615 
2616 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2617 			btrfsic_print_add_link(state, l);
2618 
2619 		list_add(&l->node_ref_to, &from_block->ref_to_list);
2620 		list_add(&l->node_ref_from, &next_block->ref_from_list);
2621 
2622 		btrfsic_block_link_hashtable_add(l,
2623 						 &state->block_link_hashtable);
2624 	} else {
2625 		l->ref_cnt++;
2626 		l->parent_generation = parent_generation;
2627 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2628 			btrfsic_print_add_link(state, l);
2629 	}
2630 
2631 	return l;
2632 }
2633 
2634 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2635 		struct btrfsic_state *state,
2636 		struct btrfsic_block_data_ctx *block_ctx,
2637 		const char *additional_string,
2638 		int is_metadata,
2639 		int is_iodone,
2640 		int never_written,
2641 		int mirror_num,
2642 		int *was_created)
2643 {
2644 	struct btrfsic_block *block;
2645 
2646 	block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2647 					       block_ctx->dev_bytenr,
2648 					       &state->block_hashtable);
2649 	if (NULL == block) {
2650 		struct btrfsic_dev_state *dev_state;
2651 
2652 		block = btrfsic_block_alloc();
2653 		if (NULL == block) {
2654 			pr_info("btrfsic: error, kmalloc failed!\n");
2655 			return NULL;
2656 		}
2657 		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2658 		if (NULL == dev_state) {
2659 			pr_info("btrfsic: error, lookup dev_state failed!\n");
2660 			btrfsic_block_free(block);
2661 			return NULL;
2662 		}
2663 		block->dev_state = dev_state;
2664 		block->dev_bytenr = block_ctx->dev_bytenr;
2665 		block->logical_bytenr = block_ctx->start;
2666 		block->is_metadata = is_metadata;
2667 		block->is_iodone = is_iodone;
2668 		block->never_written = never_written;
2669 		block->mirror_num = mirror_num;
2670 		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2671 			pr_info("New %s%c-block @%llu (%s/%llu/%d)\n",
2672 			       additional_string,
2673 			       btrfsic_get_block_type(state, block),
2674 			       block->logical_bytenr, dev_state->name,
2675 			       block->dev_bytenr, mirror_num);
2676 		list_add(&block->all_blocks_node, &state->all_blocks_list);
2677 		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2678 		if (NULL != was_created)
2679 			*was_created = 1;
2680 	} else {
2681 		if (NULL != was_created)
2682 			*was_created = 0;
2683 	}
2684 
2685 	return block;
2686 }
2687 
2688 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2689 					   u64 bytenr,
2690 					   struct btrfsic_dev_state *dev_state,
2691 					   u64 dev_bytenr)
2692 {
2693 	struct btrfs_fs_info *fs_info = state->fs_info;
2694 	struct btrfsic_block_data_ctx block_ctx;
2695 	int num_copies;
2696 	int mirror_num;
2697 	int match = 0;
2698 	int ret;
2699 
2700 	num_copies = btrfs_num_copies(fs_info, bytenr, state->metablock_size);
2701 
2702 	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2703 		ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2704 					&block_ctx, mirror_num);
2705 		if (ret) {
2706 			pr_info("btrfsic: btrfsic_map_block(logical @%llu, mirror %d) failed!\n",
2707 			       bytenr, mirror_num);
2708 			continue;
2709 		}
2710 
2711 		if (dev_state->bdev == block_ctx.dev->bdev &&
2712 		    dev_bytenr == block_ctx.dev_bytenr) {
2713 			match++;
2714 			btrfsic_release_block_ctx(&block_ctx);
2715 			break;
2716 		}
2717 		btrfsic_release_block_ctx(&block_ctx);
2718 	}
2719 
2720 	if (WARN_ON(!match)) {
2721 		pr_info("btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio, buffer->log_bytenr=%llu, submit_bio(bdev=%s, phys_bytenr=%llu)!\n",
2722 		       bytenr, dev_state->name, dev_bytenr);
2723 		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2724 			ret = btrfsic_map_block(state, bytenr,
2725 						state->metablock_size,
2726 						&block_ctx, mirror_num);
2727 			if (ret)
2728 				continue;
2729 
2730 			pr_info("Read logical bytenr @%llu maps to (%s/%llu/%d)\n",
2731 			       bytenr, block_ctx.dev->name,
2732 			       block_ctx.dev_bytenr, mirror_num);
2733 		}
2734 	}
2735 }
2736 
2737 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2738 		struct block_device *bdev)
2739 {
2740 	return btrfsic_dev_state_hashtable_lookup(bdev,
2741 						  &btrfsic_dev_state_hashtable);
2742 }
2743 
2744 int btrfsic_submit_bh(int op, int op_flags, struct buffer_head *bh)
2745 {
2746 	struct btrfsic_dev_state *dev_state;
2747 
2748 	if (!btrfsic_is_initialized)
2749 		return submit_bh(op, op_flags, bh);
2750 
2751 	mutex_lock(&btrfsic_mutex);
2752 	/* since btrfsic_submit_bh() might also be called before
2753 	 * btrfsic_mount(), this might return NULL */
2754 	dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
2755 
2756 	/* Only called to write the superblock (incl. FLUSH/FUA) */
2757 	if (NULL != dev_state &&
2758 	    (op == REQ_OP_WRITE) && bh->b_size > 0) {
2759 		u64 dev_bytenr;
2760 
2761 		dev_bytenr = 4096 * bh->b_blocknr;
2762 		if (dev_state->state->print_mask &
2763 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2764 			pr_info("submit_bh(op=0x%x,0x%x, blocknr=%llu (bytenr %llu), size=%zu, data=%p, bdev=%p)\n",
2765 			       op, op_flags, (unsigned long long)bh->b_blocknr,
2766 			       dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2767 		btrfsic_process_written_block(dev_state, dev_bytenr,
2768 					      &bh->b_data, 1, NULL,
2769 					      NULL, bh, op_flags);
2770 	} else if (NULL != dev_state && (op_flags & REQ_PREFLUSH)) {
2771 		if (dev_state->state->print_mask &
2772 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2773 			pr_info("submit_bh(op=0x%x,0x%x FLUSH, bdev=%p)\n",
2774 			       op, op_flags, bh->b_bdev);
2775 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2776 			if ((dev_state->state->print_mask &
2777 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2778 			      BTRFSIC_PRINT_MASK_VERBOSE)))
2779 				pr_info("btrfsic_submit_bh(%s) with FLUSH but dummy block already in use (ignored)!\n",
2780 				       dev_state->name);
2781 		} else {
2782 			struct btrfsic_block *const block =
2783 				&dev_state->dummy_block_for_bio_bh_flush;
2784 
2785 			block->is_iodone = 0;
2786 			block->never_written = 0;
2787 			block->iodone_w_error = 0;
2788 			block->flush_gen = dev_state->last_flush_gen + 1;
2789 			block->submit_bio_bh_rw = op_flags;
2790 			block->orig_bio_bh_private = bh->b_private;
2791 			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2792 			block->next_in_same_bio = NULL;
2793 			bh->b_private = block;
2794 			bh->b_end_io = btrfsic_bh_end_io;
2795 		}
2796 	}
2797 	mutex_unlock(&btrfsic_mutex);
2798 	return submit_bh(op, op_flags, bh);
2799 }
2800 
2801 static void __btrfsic_submit_bio(struct bio *bio)
2802 {
2803 	struct btrfsic_dev_state *dev_state;
2804 
2805 	if (!btrfsic_is_initialized)
2806 		return;
2807 
2808 	mutex_lock(&btrfsic_mutex);
2809 	/* since btrfsic_submit_bio() is also called before
2810 	 * btrfsic_mount(), this might return NULL */
2811 	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
2812 	if (NULL != dev_state &&
2813 	    (bio_op(bio) == REQ_OP_WRITE) && bio_has_data(bio)) {
2814 		unsigned int i = 0;
2815 		u64 dev_bytenr;
2816 		u64 cur_bytenr;
2817 		struct bio_vec bvec;
2818 		struct bvec_iter iter;
2819 		int bio_is_patched;
2820 		char **mapped_datav;
2821 		unsigned int segs = bio_segments(bio);
2822 
2823 		dev_bytenr = 512 * bio->bi_iter.bi_sector;
2824 		bio_is_patched = 0;
2825 		if (dev_state->state->print_mask &
2826 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2827 			pr_info("submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
2828 			       bio_op(bio), bio->bi_opf, segs,
2829 			       (unsigned long long)bio->bi_iter.bi_sector,
2830 			       dev_bytenr, bio->bi_bdev);
2831 
2832 		mapped_datav = kmalloc_array(segs,
2833 					     sizeof(*mapped_datav), GFP_NOFS);
2834 		if (!mapped_datav)
2835 			goto leave;
2836 		cur_bytenr = dev_bytenr;
2837 
2838 		bio_for_each_segment(bvec, bio, iter) {
2839 			BUG_ON(bvec.bv_len != PAGE_SIZE);
2840 			mapped_datav[i] = kmap(bvec.bv_page);
2841 			i++;
2842 
2843 			if (dev_state->state->print_mask &
2844 			    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
2845 				pr_info("#%u: bytenr=%llu, len=%u, offset=%u\n",
2846 				       i, cur_bytenr, bvec.bv_len, bvec.bv_offset);
2847 			cur_bytenr += bvec.bv_len;
2848 		}
2849 		btrfsic_process_written_block(dev_state, dev_bytenr,
2850 					      mapped_datav, segs,
2851 					      bio, &bio_is_patched,
2852 					      NULL, bio->bi_opf);
2853 		bio_for_each_segment(bvec, bio, iter)
2854 			kunmap(bvec.bv_page);
2855 		kfree(mapped_datav);
2856 	} else if (NULL != dev_state && (bio->bi_opf & REQ_PREFLUSH)) {
2857 		if (dev_state->state->print_mask &
2858 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2859 			pr_info("submit_bio(rw=%d,0x%x FLUSH, bdev=%p)\n",
2860 			       bio_op(bio), bio->bi_opf, bio->bi_bdev);
2861 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2862 			if ((dev_state->state->print_mask &
2863 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2864 			      BTRFSIC_PRINT_MASK_VERBOSE)))
2865 				pr_info("btrfsic_submit_bio(%s) with FLUSH but dummy block already in use (ignored)!\n",
2866 				       dev_state->name);
2867 		} else {
2868 			struct btrfsic_block *const block =
2869 				&dev_state->dummy_block_for_bio_bh_flush;
2870 
2871 			block->is_iodone = 0;
2872 			block->never_written = 0;
2873 			block->iodone_w_error = 0;
2874 			block->flush_gen = dev_state->last_flush_gen + 1;
2875 			block->submit_bio_bh_rw = bio->bi_opf;
2876 			block->orig_bio_bh_private = bio->bi_private;
2877 			block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2878 			block->next_in_same_bio = NULL;
2879 			bio->bi_private = block;
2880 			bio->bi_end_io = btrfsic_bio_end_io;
2881 		}
2882 	}
2883 leave:
2884 	mutex_unlock(&btrfsic_mutex);
2885 }
2886 
2887 void btrfsic_submit_bio(struct bio *bio)
2888 {
2889 	__btrfsic_submit_bio(bio);
2890 	submit_bio(bio);
2891 }
2892 
2893 int btrfsic_submit_bio_wait(struct bio *bio)
2894 {
2895 	__btrfsic_submit_bio(bio);
2896 	return submit_bio_wait(bio);
2897 }
2898 
2899 int btrfsic_mount(struct btrfs_fs_info *fs_info,
2900 		  struct btrfs_fs_devices *fs_devices,
2901 		  int including_extent_data, u32 print_mask)
2902 {
2903 	int ret;
2904 	struct btrfsic_state *state;
2905 	struct list_head *dev_head = &fs_devices->devices;
2906 	struct btrfs_device *device;
2907 
2908 	if (fs_info->nodesize & ((u64)PAGE_SIZE - 1)) {
2909 		pr_info("btrfsic: cannot handle nodesize %d not being a multiple of PAGE_SIZE %ld!\n",
2910 		       fs_info->nodesize, PAGE_SIZE);
2911 		return -1;
2912 	}
2913 	if (fs_info->sectorsize & ((u64)PAGE_SIZE - 1)) {
2914 		pr_info("btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_SIZE %ld!\n",
2915 		       fs_info->sectorsize, PAGE_SIZE);
2916 		return -1;
2917 	}
2918 	state = kvzalloc(sizeof(*state), GFP_KERNEL);
2919 	if (!state) {
2920 		pr_info("btrfs check-integrity: allocation failed!\n");
2921 		return -1;
2922 	}
2923 
2924 	if (!btrfsic_is_initialized) {
2925 		mutex_init(&btrfsic_mutex);
2926 		btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
2927 		btrfsic_is_initialized = 1;
2928 	}
2929 	mutex_lock(&btrfsic_mutex);
2930 	state->fs_info = fs_info;
2931 	state->print_mask = print_mask;
2932 	state->include_extent_data = including_extent_data;
2933 	state->csum_size = 0;
2934 	state->metablock_size = fs_info->nodesize;
2935 	state->datablock_size = fs_info->sectorsize;
2936 	INIT_LIST_HEAD(&state->all_blocks_list);
2937 	btrfsic_block_hashtable_init(&state->block_hashtable);
2938 	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
2939 	state->max_superblock_generation = 0;
2940 	state->latest_superblock = NULL;
2941 
2942 	list_for_each_entry(device, dev_head, dev_list) {
2943 		struct btrfsic_dev_state *ds;
2944 		const char *p;
2945 
2946 		if (!device->bdev || !device->name)
2947 			continue;
2948 
2949 		ds = btrfsic_dev_state_alloc();
2950 		if (NULL == ds) {
2951 			pr_info("btrfs check-integrity: kmalloc() failed!\n");
2952 			mutex_unlock(&btrfsic_mutex);
2953 			return -1;
2954 		}
2955 		ds->bdev = device->bdev;
2956 		ds->state = state;
2957 		bdevname(ds->bdev, ds->name);
2958 		ds->name[BDEVNAME_SIZE - 1] = '\0';
2959 		p = kbasename(ds->name);
2960 		strlcpy(ds->name, p, sizeof(ds->name));
2961 		btrfsic_dev_state_hashtable_add(ds,
2962 						&btrfsic_dev_state_hashtable);
2963 	}
2964 
2965 	ret = btrfsic_process_superblock(state, fs_devices);
2966 	if (0 != ret) {
2967 		mutex_unlock(&btrfsic_mutex);
2968 		btrfsic_unmount(fs_devices);
2969 		return ret;
2970 	}
2971 
2972 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
2973 		btrfsic_dump_database(state);
2974 	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
2975 		btrfsic_dump_tree(state);
2976 
2977 	mutex_unlock(&btrfsic_mutex);
2978 	return 0;
2979 }
2980 
2981 void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
2982 {
2983 	struct btrfsic_block *b_all, *tmp_all;
2984 	struct btrfsic_state *state;
2985 	struct list_head *dev_head = &fs_devices->devices;
2986 	struct btrfs_device *device;
2987 
2988 	if (!btrfsic_is_initialized)
2989 		return;
2990 
2991 	mutex_lock(&btrfsic_mutex);
2992 
2993 	state = NULL;
2994 	list_for_each_entry(device, dev_head, dev_list) {
2995 		struct btrfsic_dev_state *ds;
2996 
2997 		if (!device->bdev || !device->name)
2998 			continue;
2999 
3000 		ds = btrfsic_dev_state_hashtable_lookup(
3001 				device->bdev,
3002 				&btrfsic_dev_state_hashtable);
3003 		if (NULL != ds) {
3004 			state = ds->state;
3005 			btrfsic_dev_state_hashtable_remove(ds);
3006 			btrfsic_dev_state_free(ds);
3007 		}
3008 	}
3009 
3010 	if (NULL == state) {
3011 		pr_info("btrfsic: error, cannot find state information on umount!\n");
3012 		mutex_unlock(&btrfsic_mutex);
3013 		return;
3014 	}
3015 
3016 	/*
3017 	 * Don't care about keeping the lists' state up to date,
3018 	 * just free all memory that was allocated dynamically.
3019 	 * Free the blocks and the block_links.
3020 	 */
3021 	list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
3022 				 all_blocks_node) {
3023 		struct btrfsic_block_link *l, *tmp;
3024 
3025 		list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
3026 					 node_ref_to) {
3027 			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3028 				btrfsic_print_rem_link(state, l);
3029 
3030 			l->ref_cnt--;
3031 			if (0 == l->ref_cnt)
3032 				btrfsic_block_link_free(l);
3033 		}
3034 
3035 		if (b_all->is_iodone || b_all->never_written)
3036 			btrfsic_block_free(b_all);
3037 		else
3038 			pr_info("btrfs: attempt to free %c-block @%llu (%s/%llu/%d) on umount which is not yet iodone!\n",
3039 			       btrfsic_get_block_type(state, b_all),
3040 			       b_all->logical_bytenr, b_all->dev_state->name,
3041 			       b_all->dev_bytenr, b_all->mirror_num);
3042 	}
3043 
3044 	mutex_unlock(&btrfsic_mutex);
3045 
3046 	kvfree(state);
3047 }
3048