1 // SPDX-License-Identifier: GPL-2.0+ 1
2 /*
3 * Copyright (C) 2017 Oracle. All Rights Rese
4 *
5 * Author: Darrick J. Wong <darrick.wong@oracl
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. */
16 void ext4_fsmap_from_internal(struct super_blo
17 struct ext4_fsma
18 {
19 dest->fmr_device = src->fmr_device;
20 dest->fmr_flags = src->fmr_flags;
21 dest->fmr_physical = src->fmr_physical
22 dest->fmr_owner = src->fmr_owner;
23 dest->fmr_offset = 0;
24 dest->fmr_length = src->fmr_length <<
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. */
31 void ext4_fsmap_to_internal(struct super_block
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
37 dest->fmr_owner = src->fmr_owner;
38 dest->fmr_length = src->fmr_length >>
39 }
40
41 /* getfsmap query state */
42 struct ext4_getfsmap_info {
43 struct ext4_fsmap_head *gfi_head;
44 ext4_fsmap_format_t gfi_formatter;
45 void *gfi_format_ar
46 ext4_fsblk_t gfi_next_fsblk
47 u32 gfi_dev;
48 ext4_group_t gfi_agno;
49 struct ext4_fsmap gfi_low;
50 struct ext4_fsmap gfi_high;
51 struct ext4_fsmap gfi_lastfree;
52 struct list_head gfi_meta_list;
53 bool gfi_last;
54 };
55
56 /* Associate a device with a getfsmap handler.
57 struct ext4_getfsmap_dev {
58 int (*gfd_fn)(stru
59 struct e
60 struct e
61 u32 gfd_dev;
62 };
63
64 /* Compare two getfsmap device handlers. */
65 static int ext4_getfsmap_dev_compare(const voi
66 {
67 const struct ext4_getfsmap_dev *d1 = p
68 const struct ext4_getfsmap_dev *d2 = p
69
70 return d1->gfd_dev - d2->gfd_dev;
71 }
72
73 /* Compare a record against our starting point
74 static bool ext4_getfsmap_rec_before_low_key(s
75 s
76 {
77 return rec->fmr_physical < info->gfi_l
78 }
79
80 /*
81 * Format a reverse mapping for getfsmap, havi
82 * into the appropriate daddr units.
83 */
84 static int ext4_getfsmap_helper(struct super_b
85 struct ext4_ge
86 struct ext4_fs
87 {
88 struct ext4_fsmap fmr;
89 struct ext4_sb_info *sbi = EXT4_SB(sb)
90 ext4_fsblk_t rec_fsblk = rec->fmr_phys
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 befor
100 * caller requested that.
101 */
102 if (ext4_getfsmap_rec_before_low_key(i
103 rec_fsblk += rec->fmr_length;
104 if (info->gfi_next_fsblk < rec
105 info->gfi_next_fsblk =
106 return EXT4_QUERY_RANGE_CONTIN
107 }
108
109 /* Are we just counting mappings? */
110 if (info->gfi_head->fmh_count == 0) {
111 if (info->gfi_head->fmh_entrie
112 return EXT4_QUERY_RANG
113
114 if (rec_fsblk > info->gfi_next
115 info->gfi_head->fmh_en
116
117 if (info->gfi_last)
118 return EXT4_QUERY_RANG
119
120 info->gfi_head->fmh_entries++;
121
122 rec_fsblk += rec->fmr_length;
123 if (info->gfi_next_fsblk < rec
124 info->gfi_next_fsblk =
125 return EXT4_QUERY_RANGE_CONTIN
126 }
127
128 /*
129 * If the record starts past the last
130 * then we've found a gap. Report the
131 * whatever the caller specified is th
132 */
133 if (rec_fsblk > info->gfi_next_fsblk)
134 if (info->gfi_head->fmh_entrie
135 return EXT4_QUERY_RANG
136
137 ext4_get_group_no_and_offset(s
138 &agno, &cno);
139 trace_ext4_fsmap_mapping(sb, i
140 EXT4_C2B(sbi,
141 rec_fsblk - in
142 EXT4_FMR_OWN_U
143
144 fmr.fmr_device = info->gfi_dev
145 fmr.fmr_physical = info->gfi_n
146 fmr.fmr_owner = EXT4_FMR_OWN_U
147 fmr.fmr_length = rec_fsblk - i
148 fmr.fmr_flags = FMR_OF_SPECIAL
149 error = info->gfi_formatter(&f
150 if (error)
151 return error;
152 info->gfi_head->fmh_entries++;
153 }
154
155 if (info->gfi_last)
156 goto out;
157
158 /* Fill out the extent we found */
159 if (info->gfi_head->fmh_entries >= inf
160 return EXT4_QUERY_RANGE_ABORT;
161
162 ext4_get_group_no_and_offset(sb, rec_f
163 trace_ext4_fsmap_mapping(sb, info->gfi
164 rec->fmr_length, rec->
165
166 fmr.fmr_device = info->gfi_dev;
167 fmr.fmr_physical = rec_fsblk;
168 fmr.fmr_owner = rec->fmr_owner;
169 fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
170 fmr.fmr_length = rec->fmr_length;
171 error = info->gfi_formatter(&fmr, info
172 if (error)
173 return error;
174 info->gfi_head->fmh_entries++;
175
176 out:
177 rec_fsblk += rec->fmr_length;
178 if (info->gfi_next_fsblk < rec_fsblk)
179 info->gfi_next_fsblk = rec_fsb
180 return EXT4_QUERY_RANGE_CONTINUE;
181 }
182
183 static inline ext4_fsblk_t ext4_fsmap_next_pbl
184 {
185 return fmr->fmr_physical + fmr->fmr_le
186 }
187
188 /* Transform a blockgroup's free record into a
189 static int ext4_getfsmap_datadev_helper(struct
190 ext4_g
191 ext4_g
192 {
193 struct ext4_fsmap irec;
194 struct ext4_getfsmap_info *info = priv
195 struct ext4_fsmap *p;
196 struct ext4_fsmap *tmp;
197 struct ext4_sb_info *sbi = EXT4_SB(sb)
198 ext4_fsblk_t fsb;
199 ext4_fsblk_t fslen;
200 int error;
201
202 fsb = (EXT4_C2B(sbi, start) + ext4_gro
203 fslen = EXT4_C2B(sbi, len);
204
205 /* If the retained free extent record
206 if (info->gfi_lastfree.fmr_owner) {
207 /* ...and abuts this one, leng
208 if (ext4_fsmap_next_pblk(&info
209 info->gfi_lastfree.fmr
210 return 0;
211 }
212
213 /*
214 * There's a gap between the t
215 * retained extent prior to me
216 */
217 error = ext4_getfsmap_helper(s
218 if (error)
219 return error;
220 info->gfi_lastfree.fmr_owner =
221 }
222
223 /* Merge in any relevant extents from
224 list_for_each_entry_safe(p, tmp, &info
225 if (p->fmr_physical + p->fmr_l
226 list_del(&p->fmr_list)
227 kfree(p);
228 } else if (p->fmr_physical < f
229 error = ext4_getfsmap_
230 if (error)
231 return error;
232
233 list_del(&p->fmr_list)
234 kfree(p);
235 }
236 }
237
238 irec.fmr_device = 0;
239 irec.fmr_physical = fsb;
240 irec.fmr_length = fslen;
241 irec.fmr_owner = EXT4_FMR_OWN_FREE;
242 irec.fmr_flags = 0;
243
244 /* If this is a free extent at the end
245 if (ext4_fsmap_next_pblk(&irec) ==
246 ext4_group_first_block
247 info->gfi_lastfree = irec;
248 return 0;
249 }
250
251 /* Otherwise, emit it */
252 return ext4_getfsmap_helper(sb, info,
253 }
254
255 /* Execute a getfsmap query against the log de
256 static int ext4_getfsmap_logdev(struct super_b
257 struct ext4_ge
258 {
259 journal_t *journal = EXT4_SB(sb)->s_jo
260 struct ext4_fsmap irec;
261
262 /* Set up search keys */
263 info->gfi_low = keys[0];
264 info->gfi_low.fmr_length = 0;
265
266 memset(&info->gfi_high, 0xFF, sizeof(i
267
268 trace_ext4_fsmap_low_key(sb, info->gfi
269 info->gfi_low.fmr_phys
270 info->gfi_low.fmr_leng
271 info->gfi_low.fmr_owne
272
273 trace_ext4_fsmap_high_key(sb, info->gf
274 info->gfi_high.fmr_phy
275 info->gfi_high.fmr_len
276 info->gfi_high.fmr_own
277
278 if (keys[0].fmr_physical > 0)
279 return 0;
280
281 /* Fabricate an rmap entry for the ext
282 irec.fmr_physical = journal->j_blk_off
283 irec.fmr_length = journal->j_total_len
284 irec.fmr_owner = EXT4_FMR_OWN_LOG;
285 irec.fmr_flags = 0;
286
287 return ext4_getfsmap_helper(sb, info,
288 }
289
290 /* Helper to fill out an ext4_fsmap. */
291 static inline int ext4_getfsmap_fill(struct li
292 ext4_fsbl
293 uint64_t
294 {
295 struct ext4_fsmap *fsm;
296
297 fsm = kmalloc(sizeof(*fsm), GFP_NOFS);
298 if (!fsm)
299 return -ENOMEM;
300 fsm->fmr_device = 0;
301 fsm->fmr_flags = 0;
302 fsm->fmr_physical = fsb;
303 fsm->fmr_owner = owner;
304 fsm->fmr_length = len;
305 list_add_tail(&fsm->fmr_list, meta_lis
306
307 return 0;
308 }
309
310 /*
311 * This function returns the number of file sy
312 * the beginning of a block group, including t
313 */
314 static unsigned int ext4_getfsmap_find_sb(stru
315 ext4
316 stru
317 {
318 struct ext4_sb_info *sbi = EXT4_SB(sb)
319 ext4_fsblk_t fsb = ext4_group_first_bl
320 ext4_fsblk_t len;
321 unsigned long first_meta_bg = le32_to_
322 unsigned long metagroup = agno / EXT4_
323 int error;
324
325 /* Record the superblock. */
326 if (ext4_bg_has_super(sb, agno)) {
327 error = ext4_getfsmap_fill(met
328 if (error)
329 return error;
330 fsb++;
331 }
332
333 /* Record the group descriptors. */
334 len = ext4_bg_num_gdb(sb, agno);
335 if (!len)
336 return 0;
337 error = ext4_getfsmap_fill(meta_list,
338 EXT4_FMR_OW
339 if (error)
340 return error;
341 fsb += len;
342
343 /* Reserved GDT blocks */
344 if (!ext4_has_feature_meta_bg(sb) || m
345 len = le16_to_cpu(sbi->s_es->s
346 error = ext4_getfsmap_fill(met
347 EXT
348 if (error)
349 return error;
350 }
351
352 return 0;
353 }
354
355 /* Compare two fsmap items. */
356 static int ext4_getfsmap_compare(void *priv,
357 const struct
358 const struct
359 {
360 struct ext4_fsmap *fa;
361 struct ext4_fsmap *fb;
362
363 fa = container_of(a, struct ext4_fsmap
364 fb = container_of(b, struct ext4_fsmap
365 if (fa->fmr_physical < fb->fmr_physica
366 return -1;
367 else if (fa->fmr_physical > fb->fmr_ph
368 return 1;
369 return 0;
370 }
371
372 /* Merge adjacent extents of fixed metadata. *
373 static void ext4_getfsmap_merge_fixed_metadata
374 {
375 struct ext4_fsmap *p;
376 struct ext4_fsmap *prev = NULL;
377 struct ext4_fsmap *tmp;
378
379 list_for_each_entry_safe(p, tmp, meta_
380 if (!prev) {
381 prev = p;
382 continue;
383 }
384
385 if (prev->fmr_owner == p->fmr_
386 prev->fmr_physical + prev-
387 prev->fmr_length += p-
388 list_del(&p->fmr_list)
389 kfree(p);
390 } else
391 prev = p;
392 }
393 }
394
395 /* Free a list of fixed metadata. */
396 static void ext4_getfsmap_free_fixed_metadata(
397 {
398 struct ext4_fsmap *p;
399 struct ext4_fsmap *tmp;
400
401 list_for_each_entry_safe(p, tmp, meta_
402 list_del(&p->fmr_list);
403 kfree(p);
404 }
405 }
406
407 /* Find all the fixed metadata in the filesyst
408 static int ext4_getfsmap_find_fixed_metadata(s
409 s
410 {
411 struct ext4_group_desc *gdp;
412 ext4_group_t agno;
413 int error;
414
415 INIT_LIST_HEAD(meta_list);
416
417 /* Collect everything. */
418 for (agno = 0; agno < EXT4_SB(sb)->s_g
419 gdp = ext4_get_group_desc(sb,
420 if (!gdp) {
421 error = -EFSCORRUPTED;
422 goto err;
423 }
424
425 /* Superblock & GDT */
426 error = ext4_getfsmap_find_sb(
427 if (error)
428 goto err;
429
430 /* Block bitmap */
431 error = ext4_getfsmap_fill(met
432 ext
433 EXT
434 if (error)
435 goto err;
436
437 /* Inode bitmap */
438 error = ext4_getfsmap_fill(met
439 ext
440 EXT
441 if (error)
442 goto err;
443
444 /* Inodes */
445 error = ext4_getfsmap_fill(met
446 ext
447 EXT
448 EXT
449 if (error)
450 goto err;
451 }
452
453 /* Sort the list */
454 list_sort(NULL, meta_list, ext4_getfsm
455
456 /* Merge adjacent extents */
457 ext4_getfsmap_merge_fixed_metadata(met
458
459 return 0;
460 err:
461 ext4_getfsmap_free_fixed_metadata(meta
462 return error;
463 }
464
465 /* Execute a getfsmap query against the buddy
466 static int ext4_getfsmap_datadev(struct super_
467 struct ext4_f
468 struct ext4_g
469 {
470 struct ext4_sb_info *sbi = EXT4_SB(sb)
471 ext4_fsblk_t start_fsb;
472 ext4_fsblk_t end_fsb;
473 ext4_fsblk_t bofs;
474 ext4_fsblk_t eofs;
475 ext4_group_t start_ag;
476 ext4_group_t end_ag;
477 ext4_grpblk_t first_cluster;
478 ext4_grpblk_t last_cluster;
479 int error = 0;
480
481 bofs = le32_to_cpu(sbi->s_es->s_first_
482 eofs = ext4_blocks_count(sbi->s_es);
483 if (keys[0].fmr_physical >= eofs)
484 return 0;
485 else if (keys[0].fmr_physical < bofs)
486 keys[0].fmr_physical = bofs;
487 if (keys[1].fmr_physical >= eofs)
488 keys[1].fmr_physical = eofs -
489 if (keys[1].fmr_physical < keys[0].fmr
490 return 0;
491 start_fsb = keys[0].fmr_physical;
492 end_fsb = keys[1].fmr_physical;
493
494 /* Determine first and last group to e
495 ext4_get_group_no_and_offset(sb, start
496 ext4_get_group_no_and_offset(sb, end_f
497
498 /*
499 * Convert the fsmap low/high keys to
500 * low to the fsmap low key and max ou
501 * of the bg.
502 */
503 info->gfi_low = keys[0];
504 info->gfi_low.fmr_physical = EXT4_C2B(
505 info->gfi_low.fmr_length = 0;
506
507 memset(&info->gfi_high, 0xFF, sizeof(i
508
509 /* Assemble a list of all the fixed-lo
510 error = ext4_getfsmap_find_fixed_metad
511 if (error)
512 goto err;
513
514 /* Query each bg */
515 for (info->gfi_agno = start_ag;
516 info->gfi_agno <= end_ag;
517 info->gfi_agno++) {
518 /*
519 * Set the bg high key from th
520 * is the last bg that we're q
521 */
522 if (info->gfi_agno == end_ag)
523 info->gfi_high = keys[
524 info->gfi_high.fmr_phy
525 last_c
526 info->gfi_high.fmr_len
527 }
528
529 trace_ext4_fsmap_low_key(sb, i
530 info->gfi_low.
531 info->gfi_low.
532 info->gfi_low.
533
534 trace_ext4_fsmap_high_key(sb,
535 info->gfi_high
536 info->gfi_high
537 info->gfi_high
538
539 error = ext4_mballoc_query_ran
540 EXT4_B2C(sbi,
541 EXT4_B2C(sbi,
542 ext4_getfsmap_
543 if (error)
544 goto err;
545
546 /*
547 * Set the bg low key to the s
548 * moving on to the next bg.
549 */
550 if (info->gfi_agno == start_ag
551 memset(&info->gfi_low,
552 }
553
554 /* Do we have a retained free extent?
555 if (info->gfi_lastfree.fmr_owner) {
556 error = ext4_getfsmap_helper(s
557 if (error)
558 goto err;
559 }
560
561 /* Report any gaps at the end of the b
562 info->gfi_last = true;
563 error = ext4_getfsmap_datadev_helper(s
564 if (error)
565 goto err;
566
567 err:
568 ext4_getfsmap_free_fixed_metadata(&inf
569 return error;
570 }
571
572 /* Do we recognize the device? */
573 static bool ext4_getfsmap_is_valid_device(stru
574 stru
575 {
576 if (fm->fmr_device == 0 || fm->fmr_dev
577 fm->fmr_device == new_encode_dev(s
578 return true;
579 if (EXT4_SB(sb)->s_journal_bdev_file &
580 fm->fmr_device ==
581 new_encode_dev(file_bdev(EXT4_SB(s
582 return true;
583 return false;
584 }
585
586 /* Ensure that the low key is less than the hi
587 static bool ext4_getfsmap_check_keys(struct ex
588 struct ex
589 {
590 if (low_key->fmr_device > high_key->fm
591 return false;
592 if (low_key->fmr_device < high_key->fm
593 return true;
594
595 if (low_key->fmr_physical > high_key->
596 return false;
597 if (low_key->fmr_physical < high_key->
598 return true;
599
600 if (low_key->fmr_owner > high_key->fmr
601 return false;
602 if (low_key->fmr_owner < high_key->fmr
603 return true;
604
605 return false;
606 }
607
608 #define EXT4_GETFSMAP_DEVS 2
609 /*
610 * Get filesystem's extents as described in he
611 * output. Calls formatter to fill the user's
612 * extents are mapped, until the passed-in hea
613 * been filled, or until the formatter short-c
614 * is tracking filled-in extents on its own.
615 *
616 * Key to Confusion
617 * ----------------
618 * There are multiple levels of keys and count
619 * _fsmap_head.fmh_keys -- low and hig
620 * these refle
621 * dkeys -- fmh_keys us
622 * these are f
623 * bumped up b
624 * _getfsmap_info.gfi_next_fsblk-- next fs blo
625 * is how we d
626 * records and
627 * _getfsmap_info.gfi_low/high -- per-bg low/
628 * dkeys; used
629 */
630 int ext4_getfsmap(struct super_block *sb, stru
631 ext4_fsmap_format_t formatte
632 {
633 struct ext4_fsmap dkeys[2]; /* per
634 struct ext4_getfsmap_dev handlers[EXT4
635 struct ext4_getfsmap_info info = { NUL
636 int i;
637 int error = 0;
638
639 if (head->fmh_iflags & ~FMH_IF_VALID)
640 return -EINVAL;
641 if (!ext4_getfsmap_is_valid_device(sb,
642 !ext4_getfsmap_is_valid_device(sb,
643 return -EINVAL;
644
645 head->fmh_entries = 0;
646
647 /* Set up our device handlers. */
648 memset(handlers, 0, sizeof(handlers));
649 handlers[0].gfd_dev = new_encode_dev(s
650 handlers[0].gfd_fn = ext4_getfsmap_dat
651 if (EXT4_SB(sb)->s_journal_bdev_file)
652 handlers[1].gfd_dev = new_enco
653 file_bdev(EXT4_SB(sb)-
654 handlers[1].gfd_fn = ext4_getf
655 }
656
657 sort(handlers, EXT4_GETFSMAP_DEVS, siz
658 ext4_getfsmap_dev_comp
659
660 /*
661 * To continue where we left off, we a
662 * last mapping from a previous call a
663 * This is identified by a non-zero le
664 * have to increment the low key in th
665 * don't return the same mapping again
666 * very next mapping.
667 *
668 * Bump the physical offset as there c
669 * the same physical block range.
670 */
671 dkeys[0] = head->fmh_keys[0];
672 dkeys[0].fmr_physical += dkeys[0].fmr_
673 dkeys[0].fmr_owner = 0;
674 dkeys[0].fmr_length = 0;
675 memset(&dkeys[1], 0xFF, sizeof(struct
676
677 if (!ext4_getfsmap_check_keys(dkeys, &
678 return -EINVAL;
679
680 info.gfi_next_fsblk = head->fmh_keys[0
681 head->fmh_keys[0].fm
682 info.gfi_formatter = formatter;
683 info.gfi_format_arg = arg;
684 info.gfi_head = head;
685
686 /* For each device we support... */
687 for (i = 0; i < EXT4_GETFSMAP_DEVS; i+
688 /* Is this device within the r
689 if (!handlers[i].gfd_fn)
690 continue;
691 if (head->fmh_keys[0].fmr_devi
692 continue;
693 if (head->fmh_keys[1].fmr_devi
694 break;
695
696 /*
697 * If this device number match
698 * to pass the high key to the
699 * query results. If the devi
700 * low key, zero out the low k
701 * everything from the beginni
702 */
703 if (handlers[i].gfd_dev == hea
704 dkeys[1] = head->fmh_k
705 if (handlers[i].gfd_dev > head
706 memset(&dkeys[0], 0, s
707
708 info.gfi_dev = handlers[i].gfd
709 info.gfi_last = false;
710 info.gfi_agno = -1;
711 error = handlers[i].gfd_fn(sb,
712 if (error)
713 break;
714 info.gfi_next_fsblk = 0;
715 }
716
717 head->fmh_oflags = FMH_OF_DEV_T;
718 return error;
719 }
720
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