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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2017 Oracle. All Rights Reserved.
4 *
5 * Author: Darrick J. Wong <darrick.wong@oracle.com>
6 */
7#include "ext4.h"
8#include <linux/fsmap.h>
9#include "fsmap.h"
10#include "mballoc.h"
11#include <linux/sort.h>
12#include <linux/list_sort.h>
13#include <trace/events/ext4.h>
14
15/* Convert an ext4_fsmap to an fsmap. */
16void ext4_fsmap_from_internal(struct super_block *sb, struct fsmap *dest,
17 struct ext4_fsmap *src)
18{
19 dest->fmr_device = src->fmr_device;
20 dest->fmr_flags = src->fmr_flags;
21 dest->fmr_physical = src->fmr_physical << sb->s_blocksize_bits;
22 dest->fmr_owner = src->fmr_owner;
23 dest->fmr_offset = 0;
24 dest->fmr_length = src->fmr_length << sb->s_blocksize_bits;
25 dest->fmr_reserved[0] = 0;
26 dest->fmr_reserved[1] = 0;
27 dest->fmr_reserved[2] = 0;
28}
29
30/* Convert an fsmap to an ext4_fsmap. */
31void ext4_fsmap_to_internal(struct super_block *sb, struct ext4_fsmap *dest,
32 struct fsmap *src)
33{
34 dest->fmr_device = src->fmr_device;
35 dest->fmr_flags = src->fmr_flags;
36 dest->fmr_physical = src->fmr_physical >> sb->s_blocksize_bits;
37 dest->fmr_owner = src->fmr_owner;
38 dest->fmr_length = src->fmr_length >> sb->s_blocksize_bits;
39}
40
41/* getfsmap query state */
42struct ext4_getfsmap_info {
43 struct ext4_fsmap_head *gfi_head;
44 ext4_fsmap_format_t gfi_formatter; /* formatting fn */
45 void *gfi_format_arg;/* format buffer */
46 ext4_fsblk_t gfi_next_fsblk; /* next fsblock we expect */
47 u32 gfi_dev; /* device id */
48 ext4_group_t gfi_agno; /* bg number, if applicable */
49 struct ext4_fsmap gfi_low; /* low rmap key */
50 struct ext4_fsmap gfi_high; /* high rmap key */
51 struct ext4_fsmap gfi_lastfree; /* free ext at end of last bg */
52 struct list_head gfi_meta_list; /* fixed metadata list */
53 bool gfi_last; /* last extent? */
54};
55
56/* Associate a device with a getfsmap handler. */
57struct ext4_getfsmap_dev {
58 int (*gfd_fn)(struct super_block *sb,
59 struct ext4_fsmap *keys,
60 struct ext4_getfsmap_info *info);
61 u32 gfd_dev;
62};
63
64/* Compare two getfsmap device handlers. */
65static int ext4_getfsmap_dev_compare(const void *p1, const void *p2)
66{
67 const struct ext4_getfsmap_dev *d1 = p1;
68 const struct ext4_getfsmap_dev *d2 = p2;
69
70 return d1->gfd_dev - d2->gfd_dev;
71}
72
73/* Compare a record against our starting point */
74static bool ext4_getfsmap_rec_before_low_key(struct ext4_getfsmap_info *info,
75 struct ext4_fsmap *rec)
76{
77 return rec->fmr_physical < info->gfi_low.fmr_physical;
78}
79
80/*
81 * Format a reverse mapping for getfsmap, having translated rm_startblock
82 * into the appropriate daddr units.
83 */
84static int ext4_getfsmap_helper(struct super_block *sb,
85 struct ext4_getfsmap_info *info,
86 struct ext4_fsmap *rec)
87{
88 struct ext4_fsmap fmr;
89 struct ext4_sb_info *sbi = EXT4_SB(sb);
90 ext4_fsblk_t rec_fsblk = rec->fmr_physical;
91 ext4_group_t agno;
92 ext4_grpblk_t cno;
93 int error;
94
95 if (fatal_signal_pending(current))
96 return -EINTR;
97
98 /*
99 * Filter out records that start before our startpoint, if the
100 * caller requested that.
101 */
102 if (ext4_getfsmap_rec_before_low_key(info, rec)) {
103 rec_fsblk += rec->fmr_length;
104 if (info->gfi_next_fsblk < rec_fsblk)
105 info->gfi_next_fsblk = rec_fsblk;
106 return EXT4_QUERY_RANGE_CONTINUE;
107 }
108
109 /* Are we just counting mappings? */
110 if (info->gfi_head->fmh_count == 0) {
111 if (rec_fsblk > info->gfi_next_fsblk)
112 info->gfi_head->fmh_entries++;
113
114 if (info->gfi_last)
115 return EXT4_QUERY_RANGE_CONTINUE;
116
117 info->gfi_head->fmh_entries++;
118
119 rec_fsblk += rec->fmr_length;
120 if (info->gfi_next_fsblk < rec_fsblk)
121 info->gfi_next_fsblk = rec_fsblk;
122 return EXT4_QUERY_RANGE_CONTINUE;
123 }
124
125 /*
126 * If the record starts past the last physical block we saw,
127 * then we've found a gap. Report the gap as being owned by
128 * whatever the caller specified is the missing owner.
129 */
130 if (rec_fsblk > info->gfi_next_fsblk) {
131 if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count)
132 return EXT4_QUERY_RANGE_ABORT;
133
134 ext4_get_group_no_and_offset(sb, info->gfi_next_fsblk,
135 &agno, &cno);
136 trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno,
137 EXT4_C2B(sbi, cno),
138 rec_fsblk - info->gfi_next_fsblk,
139 EXT4_FMR_OWN_UNKNOWN);
140
141 fmr.fmr_device = info->gfi_dev;
142 fmr.fmr_physical = info->gfi_next_fsblk;
143 fmr.fmr_owner = EXT4_FMR_OWN_UNKNOWN;
144 fmr.fmr_length = rec_fsblk - info->gfi_next_fsblk;
145 fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
146 error = info->gfi_formatter(&fmr, info->gfi_format_arg);
147 if (error)
148 return error;
149 info->gfi_head->fmh_entries++;
150 }
151
152 if (info->gfi_last)
153 goto out;
154
155 /* Fill out the extent we found */
156 if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count)
157 return EXT4_QUERY_RANGE_ABORT;
158
159 ext4_get_group_no_and_offset(sb, rec_fsblk, &agno, &cno);
160 trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno, EXT4_C2B(sbi, cno),
161 rec->fmr_length, rec->fmr_owner);
162
163 fmr.fmr_device = info->gfi_dev;
164 fmr.fmr_physical = rec_fsblk;
165 fmr.fmr_owner = rec->fmr_owner;
166 fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
167 fmr.fmr_length = rec->fmr_length;
168 error = info->gfi_formatter(&fmr, info->gfi_format_arg);
169 if (error)
170 return error;
171 info->gfi_head->fmh_entries++;
172
173out:
174 rec_fsblk += rec->fmr_length;
175 if (info->gfi_next_fsblk < rec_fsblk)
176 info->gfi_next_fsblk = rec_fsblk;
177 return EXT4_QUERY_RANGE_CONTINUE;
178}
179
180static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr)
181{
182 return fmr->fmr_physical + fmr->fmr_length;
183}
184
185/* Transform a blockgroup's free record into a fsmap */
186static int ext4_getfsmap_datadev_helper(struct super_block *sb,
187 ext4_group_t agno, ext4_grpblk_t start,
188 ext4_grpblk_t len, void *priv)
189{
190 struct ext4_fsmap irec;
191 struct ext4_getfsmap_info *info = priv;
192 struct ext4_fsmap *p;
193 struct ext4_fsmap *tmp;
194 struct ext4_sb_info *sbi = EXT4_SB(sb);
195 ext4_fsblk_t fsb;
196 ext4_fsblk_t fslen;
197 int error;
198
199 fsb = (EXT4_C2B(sbi, start) + ext4_group_first_block_no(sb, agno));
200 fslen = EXT4_C2B(sbi, len);
201
202 /* If the retained free extent record is set... */
203 if (info->gfi_lastfree.fmr_owner) {
204 /* ...and abuts this one, lengthen it and return. */
205 if (ext4_fsmap_next_pblk(&info->gfi_lastfree) == fsb) {
206 info->gfi_lastfree.fmr_length += fslen;
207 return 0;
208 }
209
210 /*
211 * There's a gap between the two free extents; emit the
212 * retained extent prior to merging the meta_list.
213 */
214 error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree);
215 if (error)
216 return error;
217 info->gfi_lastfree.fmr_owner = 0;
218 }
219
220 /* Merge in any relevant extents from the meta_list */
221 list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) {
222 if (p->fmr_physical + p->fmr_length <= info->gfi_next_fsblk) {
223 list_del(&p->fmr_list);
224 kfree(p);
225 } else if (p->fmr_physical < fsb) {
226 error = ext4_getfsmap_helper(sb, info, p);
227 if (error)
228 return error;
229
230 list_del(&p->fmr_list);
231 kfree(p);
232 }
233 }
234
235 irec.fmr_device = 0;
236 irec.fmr_physical = fsb;
237 irec.fmr_length = fslen;
238 irec.fmr_owner = EXT4_FMR_OWN_FREE;
239 irec.fmr_flags = 0;
240
241 /* If this is a free extent at the end of a bg, buffer it. */
242 if (ext4_fsmap_next_pblk(&irec) ==
243 ext4_group_first_block_no(sb, agno + 1)) {
244 info->gfi_lastfree = irec;
245 return 0;
246 }
247
248 /* Otherwise, emit it */
249 return ext4_getfsmap_helper(sb, info, &irec);
250}
251
252/* Execute a getfsmap query against the log device. */
253static int ext4_getfsmap_logdev(struct super_block *sb, struct ext4_fsmap *keys,
254 struct ext4_getfsmap_info *info)
255{
256 journal_t *journal = EXT4_SB(sb)->s_journal;
257 struct ext4_fsmap irec;
258
259 /* Set up search keys */
260 info->gfi_low = keys[0];
261 info->gfi_low.fmr_length = 0;
262
263 memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high));
264
265 trace_ext4_fsmap_low_key(sb, info->gfi_dev, 0,
266 info->gfi_low.fmr_physical,
267 info->gfi_low.fmr_length,
268 info->gfi_low.fmr_owner);
269
270 trace_ext4_fsmap_high_key(sb, info->gfi_dev, 0,
271 info->gfi_high.fmr_physical,
272 info->gfi_high.fmr_length,
273 info->gfi_high.fmr_owner);
274
275 if (keys[0].fmr_physical > 0)
276 return 0;
277
278 /* Fabricate an rmap entry for the external log device. */
279 irec.fmr_physical = journal->j_blk_offset;
280 irec.fmr_length = journal->j_maxlen;
281 irec.fmr_owner = EXT4_FMR_OWN_LOG;
282 irec.fmr_flags = 0;
283
284 return ext4_getfsmap_helper(sb, info, &irec);
285}
286
287/* Helper to fill out an ext4_fsmap. */
288static inline int ext4_getfsmap_fill(struct list_head *meta_list,
289 ext4_fsblk_t fsb, ext4_fsblk_t len,
290 uint64_t owner)
291{
292 struct ext4_fsmap *fsm;
293
294 fsm = kmalloc(sizeof(*fsm), GFP_NOFS);
295 if (!fsm)
296 return -ENOMEM;
297 fsm->fmr_device = 0;
298 fsm->fmr_flags = 0;
299 fsm->fmr_physical = fsb;
300 fsm->fmr_owner = owner;
301 fsm->fmr_length = len;
302 list_add_tail(&fsm->fmr_list, meta_list);
303
304 return 0;
305}
306
307/*
308 * This function returns the number of file system metadata blocks at
309 * the beginning of a block group, including the reserved gdt blocks.
310 */
311static unsigned int ext4_getfsmap_find_sb(struct super_block *sb,
312 ext4_group_t agno,
313 struct list_head *meta_list)
314{
315 struct ext4_sb_info *sbi = EXT4_SB(sb);
316 ext4_fsblk_t fsb = ext4_group_first_block_no(sb, agno);
317 ext4_fsblk_t len;
318 unsigned long first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
319 unsigned long metagroup = agno / EXT4_DESC_PER_BLOCK(sb);
320 int error;
321
322 /* Record the superblock. */
323 if (ext4_bg_has_super(sb, agno)) {
324 error = ext4_getfsmap_fill(meta_list, fsb, 1, EXT4_FMR_OWN_FS);
325 if (error)
326 return error;
327 fsb++;
328 }
329
330 /* Record the group descriptors. */
331 len = ext4_bg_num_gdb(sb, agno);
332 if (!len)
333 return 0;
334 error = ext4_getfsmap_fill(meta_list, fsb, len,
335 EXT4_FMR_OWN_GDT);
336 if (error)
337 return error;
338 fsb += len;
339
340 /* Reserved GDT blocks */
341 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) {
342 len = le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
343 error = ext4_getfsmap_fill(meta_list, fsb, len,
344 EXT4_FMR_OWN_RESV_GDT);
345 if (error)
346 return error;
347 }
348
349 return 0;
350}
351
352/* Compare two fsmap items. */
353static int ext4_getfsmap_compare(void *priv,
354 struct list_head *a,
355 struct list_head *b)
356{
357 struct ext4_fsmap *fa;
358 struct ext4_fsmap *fb;
359
360 fa = container_of(a, struct ext4_fsmap, fmr_list);
361 fb = container_of(b, struct ext4_fsmap, fmr_list);
362 if (fa->fmr_physical < fb->fmr_physical)
363 return -1;
364 else if (fa->fmr_physical > fb->fmr_physical)
365 return 1;
366 return 0;
367}
368
369/* Merge adjacent extents of fixed metadata. */
370static void ext4_getfsmap_merge_fixed_metadata(struct list_head *meta_list)
371{
372 struct ext4_fsmap *p;
373 struct ext4_fsmap *prev = NULL;
374 struct ext4_fsmap *tmp;
375
376 list_for_each_entry_safe(p, tmp, meta_list, fmr_list) {
377 if (!prev) {
378 prev = p;
379 continue;
380 }
381
382 if (prev->fmr_owner == p->fmr_owner &&
383 prev->fmr_physical + prev->fmr_length == p->fmr_physical) {
384 prev->fmr_length += p->fmr_length;
385 list_del(&p->fmr_list);
386 kfree(p);
387 } else
388 prev = p;
389 }
390}
391
392/* Free a list of fixed metadata. */
393static void ext4_getfsmap_free_fixed_metadata(struct list_head *meta_list)
394{
395 struct ext4_fsmap *p;
396 struct ext4_fsmap *tmp;
397
398 list_for_each_entry_safe(p, tmp, meta_list, fmr_list) {
399 list_del(&p->fmr_list);
400 kfree(p);
401 }
402}
403
404/* Find all the fixed metadata in the filesystem. */
405static int ext4_getfsmap_find_fixed_metadata(struct super_block *sb,
406 struct list_head *meta_list)
407{
408 struct ext4_group_desc *gdp;
409 ext4_group_t agno;
410 int error;
411
412 INIT_LIST_HEAD(meta_list);
413
414 /* Collect everything. */
415 for (agno = 0; agno < EXT4_SB(sb)->s_groups_count; agno++) {
416 gdp = ext4_get_group_desc(sb, agno, NULL);
417 if (!gdp) {
418 error = -EFSCORRUPTED;
419 goto err;
420 }
421
422 /* Superblock & GDT */
423 error = ext4_getfsmap_find_sb(sb, agno, meta_list);
424 if (error)
425 goto err;
426
427 /* Block bitmap */
428 error = ext4_getfsmap_fill(meta_list,
429 ext4_block_bitmap(sb, gdp), 1,
430 EXT4_FMR_OWN_BLKBM);
431 if (error)
432 goto err;
433
434 /* Inode bitmap */
435 error = ext4_getfsmap_fill(meta_list,
436 ext4_inode_bitmap(sb, gdp), 1,
437 EXT4_FMR_OWN_INOBM);
438 if (error)
439 goto err;
440
441 /* Inodes */
442 error = ext4_getfsmap_fill(meta_list,
443 ext4_inode_table(sb, gdp),
444 EXT4_SB(sb)->s_itb_per_group,
445 EXT4_FMR_OWN_INODES);
446 if (error)
447 goto err;
448 }
449
450 /* Sort the list */
451 list_sort(NULL, meta_list, ext4_getfsmap_compare);
452
453 /* Merge adjacent extents */
454 ext4_getfsmap_merge_fixed_metadata(meta_list);
455
456 return 0;
457err:
458 ext4_getfsmap_free_fixed_metadata(meta_list);
459 return error;
460}
461
462/* Execute a getfsmap query against the buddy bitmaps */
463static int ext4_getfsmap_datadev(struct super_block *sb,
464 struct ext4_fsmap *keys,
465 struct ext4_getfsmap_info *info)
466{
467 struct ext4_sb_info *sbi = EXT4_SB(sb);
468 ext4_fsblk_t start_fsb;
469 ext4_fsblk_t end_fsb;
470 ext4_fsblk_t bofs;
471 ext4_fsblk_t eofs;
472 ext4_group_t start_ag;
473 ext4_group_t end_ag;
474 ext4_grpblk_t first_cluster;
475 ext4_grpblk_t last_cluster;
476 int error = 0;
477
478 bofs = le32_to_cpu(sbi->s_es->s_first_data_block);
479 eofs = ext4_blocks_count(sbi->s_es);
480 if (keys[0].fmr_physical >= eofs)
481 return 0;
482 else if (keys[0].fmr_physical < bofs)
483 keys[0].fmr_physical = bofs;
484 if (keys[1].fmr_physical >= eofs)
485 keys[1].fmr_physical = eofs - 1;
486 start_fsb = keys[0].fmr_physical;
487 end_fsb = keys[1].fmr_physical;
488
489 /* Determine first and last group to examine based on start and end */
490 ext4_get_group_no_and_offset(sb, start_fsb, &start_ag, &first_cluster);
491 ext4_get_group_no_and_offset(sb, end_fsb, &end_ag, &last_cluster);
492
493 /*
494 * Convert the fsmap low/high keys to bg based keys. Initialize
495 * low to the fsmap low key and max out the high key to the end
496 * of the bg.
497 */
498 info->gfi_low = keys[0];
499 info->gfi_low.fmr_physical = EXT4_C2B(sbi, first_cluster);
500 info->gfi_low.fmr_length = 0;
501
502 memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high));
503
504 /* Assemble a list of all the fixed-location metadata. */
505 error = ext4_getfsmap_find_fixed_metadata(sb, &info->gfi_meta_list);
506 if (error)
507 goto err;
508
509 /* Query each bg */
510 for (info->gfi_agno = start_ag;
511 info->gfi_agno <= end_ag;
512 info->gfi_agno++) {
513 /*
514 * Set the bg high key from the fsmap high key if this
515 * is the last bg that we're querying.
516 */
517 if (info->gfi_agno == end_ag) {
518 info->gfi_high = keys[1];
519 info->gfi_high.fmr_physical = EXT4_C2B(sbi,
520 last_cluster);
521 info->gfi_high.fmr_length = 0;
522 }
523
524 trace_ext4_fsmap_low_key(sb, info->gfi_dev, info->gfi_agno,
525 info->gfi_low.fmr_physical,
526 info->gfi_low.fmr_length,
527 info->gfi_low.fmr_owner);
528
529 trace_ext4_fsmap_high_key(sb, info->gfi_dev, info->gfi_agno,
530 info->gfi_high.fmr_physical,
531 info->gfi_high.fmr_length,
532 info->gfi_high.fmr_owner);
533
534 error = ext4_mballoc_query_range(sb, info->gfi_agno,
535 EXT4_B2C(sbi, info->gfi_low.fmr_physical),
536 EXT4_B2C(sbi, info->gfi_high.fmr_physical),
537 ext4_getfsmap_datadev_helper, info);
538 if (error)
539 goto err;
540
541 /*
542 * Set the bg low key to the start of the bg prior to
543 * moving on to the next bg.
544 */
545 if (info->gfi_agno == start_ag)
546 memset(&info->gfi_low, 0, sizeof(info->gfi_low));
547 }
548
549 /* Do we have a retained free extent? */
550 if (info->gfi_lastfree.fmr_owner) {
551 error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree);
552 if (error)
553 goto err;
554 }
555
556 /* Report any gaps at the end of the bg */
557 info->gfi_last = true;
558 error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster, 0, info);
559 if (error)
560 goto err;
561
562err:
563 ext4_getfsmap_free_fixed_metadata(&info->gfi_meta_list);
564 return error;
565}
566
567/* Do we recognize the device? */
568static bool ext4_getfsmap_is_valid_device(struct super_block *sb,
569 struct ext4_fsmap *fm)
570{
571 if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX ||
572 fm->fmr_device == new_encode_dev(sb->s_bdev->bd_dev))
573 return true;
574 if (EXT4_SB(sb)->journal_bdev &&
575 fm->fmr_device == new_encode_dev(EXT4_SB(sb)->journal_bdev->bd_dev))
576 return true;
577 return false;
578}
579
580/* Ensure that the low key is less than the high key. */
581static bool ext4_getfsmap_check_keys(struct ext4_fsmap *low_key,
582 struct ext4_fsmap *high_key)
583{
584 if (low_key->fmr_device > high_key->fmr_device)
585 return false;
586 if (low_key->fmr_device < high_key->fmr_device)
587 return true;
588
589 if (low_key->fmr_physical > high_key->fmr_physical)
590 return false;
591 if (low_key->fmr_physical < high_key->fmr_physical)
592 return true;
593
594 if (low_key->fmr_owner > high_key->fmr_owner)
595 return false;
596 if (low_key->fmr_owner < high_key->fmr_owner)
597 return true;
598
599 return false;
600}
601
602#define EXT4_GETFSMAP_DEVS 2
603/*
604 * Get filesystem's extents as described in head, and format for
605 * output. Calls formatter to fill the user's buffer until all
606 * extents are mapped, until the passed-in head->fmh_count slots have
607 * been filled, or until the formatter short-circuits the loop, if it
608 * is tracking filled-in extents on its own.
609 *
610 * Key to Confusion
611 * ----------------
612 * There are multiple levels of keys and counters at work here:
613 * _fsmap_head.fmh_keys -- low and high fsmap keys passed in;
614 * these reflect fs-wide block addrs.
615 * dkeys -- fmh_keys used to query each device;
616 * these are fmh_keys but w/ the low key
617 * bumped up by fmr_length.
618 * _getfsmap_info.gfi_next_fsblk-- next fs block we expect to see; this
619 * is how we detect gaps in the fsmap
620 * records and report them.
621 * _getfsmap_info.gfi_low/high -- per-bg low/high keys computed from
622 * dkeys; used to query the free space.
623 */
624int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head,
625 ext4_fsmap_format_t formatter, void *arg)
626{
627 struct ext4_fsmap dkeys[2]; /* per-dev keys */
628 struct ext4_getfsmap_dev handlers[EXT4_GETFSMAP_DEVS];
629 struct ext4_getfsmap_info info = { NULL };
630 int i;
631 int error = 0;
632
633 if (head->fmh_iflags & ~FMH_IF_VALID)
634 return -EINVAL;
635 if (!ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[0]) ||
636 !ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[1]))
637 return -EINVAL;
638
639 head->fmh_entries = 0;
640
641 /* Set up our device handlers. */
642 memset(handlers, 0, sizeof(handlers));
643 handlers[0].gfd_dev = new_encode_dev(sb->s_bdev->bd_dev);
644 handlers[0].gfd_fn = ext4_getfsmap_datadev;
645 if (EXT4_SB(sb)->journal_bdev) {
646 handlers[1].gfd_dev = new_encode_dev(
647 EXT4_SB(sb)->journal_bdev->bd_dev);
648 handlers[1].gfd_fn = ext4_getfsmap_logdev;
649 }
650
651 sort(handlers, EXT4_GETFSMAP_DEVS, sizeof(struct ext4_getfsmap_dev),
652 ext4_getfsmap_dev_compare, NULL);
653
654 /*
655 * To continue where we left off, we allow userspace to use the
656 * last mapping from a previous call as the low key of the next.
657 * This is identified by a non-zero length in the low key. We
658 * have to increment the low key in this scenario to ensure we
659 * don't return the same mapping again, and instead return the
660 * very next mapping.
661 *
662 * Bump the physical offset as there can be no other mapping for
663 * the same physical block range.
664 */
665 dkeys[0] = head->fmh_keys[0];
666 dkeys[0].fmr_physical += dkeys[0].fmr_length;
667 dkeys[0].fmr_owner = 0;
668 dkeys[0].fmr_length = 0;
669 memset(&dkeys[1], 0xFF, sizeof(struct ext4_fsmap));
670
671 if (!ext4_getfsmap_check_keys(dkeys, &head->fmh_keys[1]))
672 return -EINVAL;
673
674 info.gfi_next_fsblk = head->fmh_keys[0].fmr_physical +
675 head->fmh_keys[0].fmr_length;
676 info.gfi_formatter = formatter;
677 info.gfi_format_arg = arg;
678 info.gfi_head = head;
679
680 /* For each device we support... */
681 for (i = 0; i < EXT4_GETFSMAP_DEVS; i++) {
682 /* Is this device within the range the user asked for? */
683 if (!handlers[i].gfd_fn)
684 continue;
685 if (head->fmh_keys[0].fmr_device > handlers[i].gfd_dev)
686 continue;
687 if (head->fmh_keys[1].fmr_device < handlers[i].gfd_dev)
688 break;
689
690 /*
691 * If this device number matches the high key, we have
692 * to pass the high key to the handler to limit the
693 * query results. If the device number exceeds the
694 * low key, zero out the low key so that we get
695 * everything from the beginning.
696 */
697 if (handlers[i].gfd_dev == head->fmh_keys[1].fmr_device)
698 dkeys[1] = head->fmh_keys[1];
699 if (handlers[i].gfd_dev > head->fmh_keys[0].fmr_device)
700 memset(&dkeys[0], 0, sizeof(struct ext4_fsmap));
701
702 info.gfi_dev = handlers[i].gfd_dev;
703 info.gfi_last = false;
704 info.gfi_agno = -1;
705 error = handlers[i].gfd_fn(sb, dkeys, &info);
706 if (error)
707 break;
708 info.gfi_next_fsblk = 0;
709 }
710
711 head->fmh_oflags = FMH_OF_DEV_T;
712 return error;
713}