scsi: lpfc: Cleanup entry_repost settings on SLI4 queues
[linux-2.6/btrfs-unstable.git] / fs / ext4 / fsmap.c
blobb194360988371638272871cdd95ab650e58d295c
1 /*
2 * Copyright (C) 2017 Oracle. All Rights Reserved.
4 * Author: Darrick J. Wong <darrick.wong@oracle.com>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version 2
9 * of the License, or (at your option) any later version.
11 * This program is distributed in the hope that it would be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
20 #include "ext4.h"
21 #include <linux/fsmap.h>
22 #include "fsmap.h"
23 #include "mballoc.h"
24 #include <linux/sort.h>
25 #include <linux/list_sort.h>
26 #include <trace/events/ext4.h>
28 /* Convert an ext4_fsmap to an fsmap. */
29 void ext4_fsmap_from_internal(struct super_block *sb, struct fsmap *dest,
30 struct ext4_fsmap *src)
32 dest->fmr_device = src->fmr_device;
33 dest->fmr_flags = src->fmr_flags;
34 dest->fmr_physical = src->fmr_physical << sb->s_blocksize_bits;
35 dest->fmr_owner = src->fmr_owner;
36 dest->fmr_offset = 0;
37 dest->fmr_length = src->fmr_length << sb->s_blocksize_bits;
38 dest->fmr_reserved[0] = 0;
39 dest->fmr_reserved[1] = 0;
40 dest->fmr_reserved[2] = 0;
43 /* Convert an fsmap to an ext4_fsmap. */
44 void ext4_fsmap_to_internal(struct super_block *sb, struct ext4_fsmap *dest,
45 struct fsmap *src)
47 dest->fmr_device = src->fmr_device;
48 dest->fmr_flags = src->fmr_flags;
49 dest->fmr_physical = src->fmr_physical >> sb->s_blocksize_bits;
50 dest->fmr_owner = src->fmr_owner;
51 dest->fmr_length = src->fmr_length >> sb->s_blocksize_bits;
54 /* getfsmap query state */
55 struct ext4_getfsmap_info {
56 struct ext4_fsmap_head *gfi_head;
57 ext4_fsmap_format_t gfi_formatter; /* formatting fn */
58 void *gfi_format_arg;/* format buffer */
59 ext4_fsblk_t gfi_next_fsblk; /* next fsblock we expect */
60 u32 gfi_dev; /* device id */
61 ext4_group_t gfi_agno; /* bg number, if applicable */
62 struct ext4_fsmap gfi_low; /* low rmap key */
63 struct ext4_fsmap gfi_high; /* high rmap key */
64 struct ext4_fsmap gfi_lastfree; /* free ext at end of last bg */
65 struct list_head gfi_meta_list; /* fixed metadata list */
66 bool gfi_last; /* last extent? */
69 /* Associate a device with a getfsmap handler. */
70 struct ext4_getfsmap_dev {
71 int (*gfd_fn)(struct super_block *sb,
72 struct ext4_fsmap *keys,
73 struct ext4_getfsmap_info *info);
74 u32 gfd_dev;
77 /* Compare two getfsmap device handlers. */
78 static int ext4_getfsmap_dev_compare(const void *p1, const void *p2)
80 const struct ext4_getfsmap_dev *d1 = p1;
81 const struct ext4_getfsmap_dev *d2 = p2;
83 return d1->gfd_dev - d2->gfd_dev;
86 /* Compare a record against our starting point */
87 static bool ext4_getfsmap_rec_before_low_key(struct ext4_getfsmap_info *info,
88 struct ext4_fsmap *rec)
90 return rec->fmr_physical < info->gfi_low.fmr_physical;
94 * Format a reverse mapping for getfsmap, having translated rm_startblock
95 * into the appropriate daddr units.
97 static int ext4_getfsmap_helper(struct super_block *sb,
98 struct ext4_getfsmap_info *info,
99 struct ext4_fsmap *rec)
101 struct ext4_fsmap fmr;
102 struct ext4_sb_info *sbi = EXT4_SB(sb);
103 ext4_fsblk_t rec_fsblk = rec->fmr_physical;
104 ext4_group_t agno;
105 ext4_grpblk_t cno;
106 int error;
108 if (fatal_signal_pending(current))
109 return -EINTR;
112 * Filter out records that start before our startpoint, if the
113 * caller requested that.
115 if (ext4_getfsmap_rec_before_low_key(info, rec)) {
116 rec_fsblk += rec->fmr_length;
117 if (info->gfi_next_fsblk < rec_fsblk)
118 info->gfi_next_fsblk = rec_fsblk;
119 return EXT4_QUERY_RANGE_CONTINUE;
122 /* Are we just counting mappings? */
123 if (info->gfi_head->fmh_count == 0) {
124 if (rec_fsblk > info->gfi_next_fsblk)
125 info->gfi_head->fmh_entries++;
127 if (info->gfi_last)
128 return EXT4_QUERY_RANGE_CONTINUE;
130 info->gfi_head->fmh_entries++;
132 rec_fsblk += rec->fmr_length;
133 if (info->gfi_next_fsblk < rec_fsblk)
134 info->gfi_next_fsblk = rec_fsblk;
135 return EXT4_QUERY_RANGE_CONTINUE;
139 * If the record starts past the last physical block we saw,
140 * then we've found a gap. Report the gap as being owned by
141 * whatever the caller specified is the missing owner.
143 if (rec_fsblk > info->gfi_next_fsblk) {
144 if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count)
145 return EXT4_QUERY_RANGE_ABORT;
147 ext4_get_group_no_and_offset(sb, info->gfi_next_fsblk,
148 &agno, &cno);
149 trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno,
150 EXT4_C2B(sbi, cno),
151 rec_fsblk - info->gfi_next_fsblk,
152 EXT4_FMR_OWN_UNKNOWN);
154 fmr.fmr_device = info->gfi_dev;
155 fmr.fmr_physical = info->gfi_next_fsblk;
156 fmr.fmr_owner = EXT4_FMR_OWN_UNKNOWN;
157 fmr.fmr_length = rec_fsblk - info->gfi_next_fsblk;
158 fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
159 error = info->gfi_formatter(&fmr, info->gfi_format_arg);
160 if (error)
161 return error;
162 info->gfi_head->fmh_entries++;
165 if (info->gfi_last)
166 goto out;
168 /* Fill out the extent we found */
169 if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count)
170 return EXT4_QUERY_RANGE_ABORT;
172 ext4_get_group_no_and_offset(sb, rec_fsblk, &agno, &cno);
173 trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno, EXT4_C2B(sbi, cno),
174 rec->fmr_length, rec->fmr_owner);
176 fmr.fmr_device = info->gfi_dev;
177 fmr.fmr_physical = rec_fsblk;
178 fmr.fmr_owner = rec->fmr_owner;
179 fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
180 fmr.fmr_length = rec->fmr_length;
181 error = info->gfi_formatter(&fmr, info->gfi_format_arg);
182 if (error)
183 return error;
184 info->gfi_head->fmh_entries++;
186 out:
187 rec_fsblk += rec->fmr_length;
188 if (info->gfi_next_fsblk < rec_fsblk)
189 info->gfi_next_fsblk = rec_fsblk;
190 return EXT4_QUERY_RANGE_CONTINUE;
193 static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr)
195 return fmr->fmr_physical + fmr->fmr_length;
198 /* Transform a blockgroup's free record into a fsmap */
199 static int ext4_getfsmap_datadev_helper(struct super_block *sb,
200 ext4_group_t agno, ext4_grpblk_t start,
201 ext4_grpblk_t len, void *priv)
203 struct ext4_fsmap irec;
204 struct ext4_getfsmap_info *info = priv;
205 struct ext4_fsmap *p;
206 struct ext4_fsmap *tmp;
207 struct ext4_sb_info *sbi = EXT4_SB(sb);
208 ext4_fsblk_t fsb;
209 ext4_fsblk_t fslen;
210 int error;
212 fsb = (EXT4_C2B(sbi, start) + ext4_group_first_block_no(sb, agno));
213 fslen = EXT4_C2B(sbi, len);
215 /* If the retained free extent record is set... */
216 if (info->gfi_lastfree.fmr_owner) {
217 /* ...and abuts this one, lengthen it and return. */
218 if (ext4_fsmap_next_pblk(&info->gfi_lastfree) == fsb) {
219 info->gfi_lastfree.fmr_length += fslen;
220 return 0;
224 * There's a gap between the two free extents; emit the
225 * retained extent prior to merging the meta_list.
227 error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree);
228 if (error)
229 return error;
230 info->gfi_lastfree.fmr_owner = 0;
233 /* Merge in any relevant extents from the meta_list */
234 list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) {
235 if (p->fmr_physical + p->fmr_length <= info->gfi_next_fsblk) {
236 list_del(&p->fmr_list);
237 kfree(p);
238 } else if (p->fmr_physical < fsb) {
239 error = ext4_getfsmap_helper(sb, info, p);
240 if (error)
241 return error;
243 list_del(&p->fmr_list);
244 kfree(p);
248 irec.fmr_device = 0;
249 irec.fmr_physical = fsb;
250 irec.fmr_length = fslen;
251 irec.fmr_owner = EXT4_FMR_OWN_FREE;
252 irec.fmr_flags = 0;
254 /* If this is a free extent at the end of a bg, buffer it. */
255 if (ext4_fsmap_next_pblk(&irec) ==
256 ext4_group_first_block_no(sb, agno + 1)) {
257 info->gfi_lastfree = irec;
258 return 0;
261 /* Otherwise, emit it */
262 return ext4_getfsmap_helper(sb, info, &irec);
265 /* Execute a getfsmap query against the log device. */
266 static int ext4_getfsmap_logdev(struct super_block *sb, struct ext4_fsmap *keys,
267 struct ext4_getfsmap_info *info)
269 journal_t *journal = EXT4_SB(sb)->s_journal;
270 struct ext4_fsmap irec;
272 /* Set up search keys */
273 info->gfi_low = keys[0];
274 info->gfi_low.fmr_length = 0;
276 memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high));
278 trace_ext4_fsmap_low_key(sb, info->gfi_dev, 0,
279 info->gfi_low.fmr_physical,
280 info->gfi_low.fmr_length,
281 info->gfi_low.fmr_owner);
283 trace_ext4_fsmap_high_key(sb, info->gfi_dev, 0,
284 info->gfi_high.fmr_physical,
285 info->gfi_high.fmr_length,
286 info->gfi_high.fmr_owner);
288 if (keys[0].fmr_physical > 0)
289 return 0;
291 /* Fabricate an rmap entry for the external log device. */
292 irec.fmr_physical = journal->j_blk_offset;
293 irec.fmr_length = journal->j_maxlen;
294 irec.fmr_owner = EXT4_FMR_OWN_LOG;
295 irec.fmr_flags = 0;
297 return ext4_getfsmap_helper(sb, info, &irec);
300 /* Helper to fill out an ext4_fsmap. */
301 static inline int ext4_getfsmap_fill(struct list_head *meta_list,
302 ext4_fsblk_t fsb, ext4_fsblk_t len,
303 uint64_t owner)
305 struct ext4_fsmap *fsm;
307 fsm = kmalloc(sizeof(*fsm), GFP_NOFS);
308 if (!fsm)
309 return -ENOMEM;
310 fsm->fmr_device = 0;
311 fsm->fmr_flags = 0;
312 fsm->fmr_physical = fsb;
313 fsm->fmr_owner = owner;
314 fsm->fmr_length = len;
315 list_add_tail(&fsm->fmr_list, meta_list);
317 return 0;
321 * This function returns the number of file system metadata blocks at
322 * the beginning of a block group, including the reserved gdt blocks.
324 static unsigned int ext4_getfsmap_find_sb(struct super_block *sb,
325 ext4_group_t agno,
326 struct list_head *meta_list)
328 struct ext4_sb_info *sbi = EXT4_SB(sb);
329 ext4_fsblk_t fsb = ext4_group_first_block_no(sb, agno);
330 ext4_fsblk_t len;
331 unsigned long first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
332 unsigned long metagroup = agno / EXT4_DESC_PER_BLOCK(sb);
333 int error;
335 /* Record the superblock. */
336 if (ext4_bg_has_super(sb, agno)) {
337 error = ext4_getfsmap_fill(meta_list, fsb, 1, EXT4_FMR_OWN_FS);
338 if (error)
339 return error;
340 fsb++;
343 /* Record the group descriptors. */
344 len = ext4_bg_num_gdb(sb, agno);
345 if (!len)
346 return 0;
347 error = ext4_getfsmap_fill(meta_list, fsb, len,
348 EXT4_FMR_OWN_GDT);
349 if (error)
350 return error;
351 fsb += len;
353 /* Reserved GDT blocks */
354 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) {
355 len = le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
356 error = ext4_getfsmap_fill(meta_list, fsb, len,
357 EXT4_FMR_OWN_RESV_GDT);
358 if (error)
359 return error;
362 return 0;
365 /* Compare two fsmap items. */
366 static int ext4_getfsmap_compare(void *priv,
367 struct list_head *a,
368 struct list_head *b)
370 struct ext4_fsmap *fa;
371 struct ext4_fsmap *fb;
373 fa = container_of(a, struct ext4_fsmap, fmr_list);
374 fb = container_of(b, struct ext4_fsmap, fmr_list);
375 if (fa->fmr_physical < fb->fmr_physical)
376 return -1;
377 else if (fa->fmr_physical > fb->fmr_physical)
378 return 1;
379 return 0;
382 /* Merge adjacent extents of fixed metadata. */
383 static void ext4_getfsmap_merge_fixed_metadata(struct list_head *meta_list)
385 struct ext4_fsmap *p;
386 struct ext4_fsmap *prev = NULL;
387 struct ext4_fsmap *tmp;
389 list_for_each_entry_safe(p, tmp, meta_list, fmr_list) {
390 if (!prev) {
391 prev = p;
392 continue;
395 if (prev->fmr_owner == p->fmr_owner &&
396 prev->fmr_physical + prev->fmr_length == p->fmr_physical) {
397 prev->fmr_length += p->fmr_length;
398 list_del(&p->fmr_list);
399 kfree(p);
400 } else
401 prev = p;
405 /* Free a list of fixed metadata. */
406 static void ext4_getfsmap_free_fixed_metadata(struct list_head *meta_list)
408 struct ext4_fsmap *p;
409 struct ext4_fsmap *tmp;
411 list_for_each_entry_safe(p, tmp, meta_list, fmr_list) {
412 list_del(&p->fmr_list);
413 kfree(p);
417 /* Find all the fixed metadata in the filesystem. */
418 int ext4_getfsmap_find_fixed_metadata(struct super_block *sb,
419 struct list_head *meta_list)
421 struct ext4_group_desc *gdp;
422 ext4_group_t agno;
423 int error;
425 INIT_LIST_HEAD(meta_list);
427 /* Collect everything. */
428 for (agno = 0; agno < EXT4_SB(sb)->s_groups_count; agno++) {
429 gdp = ext4_get_group_desc(sb, agno, NULL);
430 if (!gdp) {
431 error = -EFSCORRUPTED;
432 goto err;
435 /* Superblock & GDT */
436 error = ext4_getfsmap_find_sb(sb, agno, meta_list);
437 if (error)
438 goto err;
440 /* Block bitmap */
441 error = ext4_getfsmap_fill(meta_list,
442 ext4_block_bitmap(sb, gdp), 1,
443 EXT4_FMR_OWN_BLKBM);
444 if (error)
445 goto err;
447 /* Inode bitmap */
448 error = ext4_getfsmap_fill(meta_list,
449 ext4_inode_bitmap(sb, gdp), 1,
450 EXT4_FMR_OWN_INOBM);
451 if (error)
452 goto err;
454 /* Inodes */
455 error = ext4_getfsmap_fill(meta_list,
456 ext4_inode_table(sb, gdp),
457 EXT4_SB(sb)->s_itb_per_group,
458 EXT4_FMR_OWN_INODES);
459 if (error)
460 goto err;
463 /* Sort the list */
464 list_sort(NULL, meta_list, ext4_getfsmap_compare);
466 /* Merge adjacent extents */
467 ext4_getfsmap_merge_fixed_metadata(meta_list);
469 return 0;
470 err:
471 ext4_getfsmap_free_fixed_metadata(meta_list);
472 return error;
475 /* Execute a getfsmap query against the buddy bitmaps */
476 static int ext4_getfsmap_datadev(struct super_block *sb,
477 struct ext4_fsmap *keys,
478 struct ext4_getfsmap_info *info)
480 struct ext4_sb_info *sbi = EXT4_SB(sb);
481 ext4_fsblk_t start_fsb;
482 ext4_fsblk_t end_fsb;
483 ext4_fsblk_t eofs;
484 ext4_group_t start_ag;
485 ext4_group_t end_ag;
486 ext4_grpblk_t first_cluster;
487 ext4_grpblk_t last_cluster;
488 int error = 0;
490 eofs = ext4_blocks_count(sbi->s_es);
491 if (keys[0].fmr_physical >= eofs)
492 return 0;
493 if (keys[1].fmr_physical >= eofs)
494 keys[1].fmr_physical = eofs - 1;
495 start_fsb = keys[0].fmr_physical;
496 end_fsb = keys[1].fmr_physical;
498 /* Determine first and last group to examine based on start and end */
499 ext4_get_group_no_and_offset(sb, start_fsb, &start_ag, &first_cluster);
500 ext4_get_group_no_and_offset(sb, end_fsb, &end_ag, &last_cluster);
503 * Convert the fsmap low/high keys to bg based keys. Initialize
504 * low to the fsmap low key and max out the high key to the end
505 * of the bg.
507 info->gfi_low = keys[0];
508 info->gfi_low.fmr_physical = EXT4_C2B(sbi, first_cluster);
509 info->gfi_low.fmr_length = 0;
511 memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high));
513 /* Assemble a list of all the fixed-location metadata. */
514 error = ext4_getfsmap_find_fixed_metadata(sb, &info->gfi_meta_list);
515 if (error)
516 goto err;
518 /* Query each bg */
519 for (info->gfi_agno = start_ag;
520 info->gfi_agno <= end_ag;
521 info->gfi_agno++) {
523 * Set the bg high key from the fsmap high key if this
524 * is the last bg that we're querying.
526 if (info->gfi_agno == end_ag) {
527 info->gfi_high = keys[1];
528 info->gfi_high.fmr_physical = EXT4_C2B(sbi,
529 last_cluster);
530 info->gfi_high.fmr_length = 0;
533 trace_ext4_fsmap_low_key(sb, info->gfi_dev, info->gfi_agno,
534 info->gfi_low.fmr_physical,
535 info->gfi_low.fmr_length,
536 info->gfi_low.fmr_owner);
538 trace_ext4_fsmap_high_key(sb, info->gfi_dev, info->gfi_agno,
539 info->gfi_high.fmr_physical,
540 info->gfi_high.fmr_length,
541 info->gfi_high.fmr_owner);
543 error = ext4_mballoc_query_range(sb, info->gfi_agno,
544 EXT4_B2C(sbi, info->gfi_low.fmr_physical),
545 EXT4_B2C(sbi, info->gfi_high.fmr_physical),
546 ext4_getfsmap_datadev_helper, info);
547 if (error)
548 goto err;
551 * Set the bg low key to the start of the bg prior to
552 * moving on to the next bg.
554 if (info->gfi_agno == start_ag)
555 memset(&info->gfi_low, 0, sizeof(info->gfi_low));
558 /* Do we have a retained free extent? */
559 if (info->gfi_lastfree.fmr_owner) {
560 error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree);
561 if (error)
562 goto err;
565 /* Report any gaps at the end of the bg */
566 info->gfi_last = true;
567 error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster, 0, info);
568 if (error)
569 goto err;
571 err:
572 ext4_getfsmap_free_fixed_metadata(&info->gfi_meta_list);
573 return error;
576 /* Do we recognize the device? */
577 static bool ext4_getfsmap_is_valid_device(struct super_block *sb,
578 struct ext4_fsmap *fm)
580 if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX ||
581 fm->fmr_device == new_encode_dev(sb->s_bdev->bd_dev))
582 return true;
583 if (EXT4_SB(sb)->journal_bdev &&
584 fm->fmr_device == new_encode_dev(EXT4_SB(sb)->journal_bdev->bd_dev))
585 return true;
586 return false;
589 /* Ensure that the low key is less than the high key. */
590 static bool ext4_getfsmap_check_keys(struct ext4_fsmap *low_key,
591 struct ext4_fsmap *high_key)
593 if (low_key->fmr_device > high_key->fmr_device)
594 return false;
595 if (low_key->fmr_device < high_key->fmr_device)
596 return true;
598 if (low_key->fmr_physical > high_key->fmr_physical)
599 return false;
600 if (low_key->fmr_physical < high_key->fmr_physical)
601 return true;
603 if (low_key->fmr_owner > high_key->fmr_owner)
604 return false;
605 if (low_key->fmr_owner < high_key->fmr_owner)
606 return true;
608 return false;
611 #define EXT4_GETFSMAP_DEVS 2
613 * Get filesystem's extents as described in head, and format for
614 * output. Calls formatter to fill the user's buffer until all
615 * extents are mapped, until the passed-in head->fmh_count slots have
616 * been filled, or until the formatter short-circuits the loop, if it
617 * is tracking filled-in extents on its own.
619 * Key to Confusion
620 * ----------------
621 * There are multiple levels of keys and counters at work here:
622 * _fsmap_head.fmh_keys -- low and high fsmap keys passed in;
623 * these reflect fs-wide block addrs.
624 * dkeys -- fmh_keys used to query each device;
625 * these are fmh_keys but w/ the low key
626 * bumped up by fmr_length.
627 * _getfsmap_info.gfi_next_fsblk-- next fs block we expect to see; this
628 * is how we detect gaps in the fsmap
629 * records and report them.
630 * _getfsmap_info.gfi_low/high -- per-bg low/high keys computed from
631 * dkeys; used to query the free space.
633 int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head,
634 ext4_fsmap_format_t formatter, void *arg)
636 struct ext4_fsmap dkeys[2]; /* per-dev keys */
637 struct ext4_getfsmap_dev handlers[EXT4_GETFSMAP_DEVS];
638 struct ext4_getfsmap_info info = {0};
639 int i;
640 int error = 0;
642 if (head->fmh_iflags & ~FMH_IF_VALID)
643 return -EINVAL;
644 if (!ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[0]) ||
645 !ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[1]))
646 return -EINVAL;
648 head->fmh_entries = 0;
650 /* Set up our device handlers. */
651 memset(handlers, 0, sizeof(handlers));
652 handlers[0].gfd_dev = new_encode_dev(sb->s_bdev->bd_dev);
653 handlers[0].gfd_fn = ext4_getfsmap_datadev;
654 if (EXT4_SB(sb)->journal_bdev) {
655 handlers[1].gfd_dev = new_encode_dev(
656 EXT4_SB(sb)->journal_bdev->bd_dev);
657 handlers[1].gfd_fn = ext4_getfsmap_logdev;
660 sort(handlers, EXT4_GETFSMAP_DEVS, sizeof(struct ext4_getfsmap_dev),
661 ext4_getfsmap_dev_compare, NULL);
664 * To continue where we left off, we allow userspace to use the
665 * last mapping from a previous call as the low key of the next.
666 * This is identified by a non-zero length in the low key. We
667 * have to increment the low key in this scenario to ensure we
668 * don't return the same mapping again, and instead return the
669 * very next mapping.
671 * Bump the physical offset as there can be no other mapping for
672 * the same physical block range.
674 dkeys[0] = head->fmh_keys[0];
675 dkeys[0].fmr_physical += dkeys[0].fmr_length;
676 dkeys[0].fmr_owner = 0;
677 dkeys[0].fmr_length = 0;
678 memset(&dkeys[1], 0xFF, sizeof(struct ext4_fsmap));
680 if (!ext4_getfsmap_check_keys(dkeys, &head->fmh_keys[1]))
681 return -EINVAL;
683 info.gfi_next_fsblk = head->fmh_keys[0].fmr_physical +
684 head->fmh_keys[0].fmr_length;
685 info.gfi_formatter = formatter;
686 info.gfi_format_arg = arg;
687 info.gfi_head = head;
689 /* For each device we support... */
690 for (i = 0; i < EXT4_GETFSMAP_DEVS; i++) {
691 /* Is this device within the range the user asked for? */
692 if (!handlers[i].gfd_fn)
693 continue;
694 if (head->fmh_keys[0].fmr_device > handlers[i].gfd_dev)
695 continue;
696 if (head->fmh_keys[1].fmr_device < handlers[i].gfd_dev)
697 break;
700 * If this device number matches the high key, we have
701 * to pass the high key to the handler to limit the
702 * query results. If the device number exceeds the
703 * low key, zero out the low key so that we get
704 * everything from the beginning.
706 if (handlers[i].gfd_dev == head->fmh_keys[1].fmr_device)
707 dkeys[1] = head->fmh_keys[1];
708 if (handlers[i].gfd_dev > head->fmh_keys[0].fmr_device)
709 memset(&dkeys[0], 0, sizeof(struct ext4_fsmap));
711 info.gfi_dev = handlers[i].gfd_dev;
712 info.gfi_last = false;
713 info.gfi_agno = -1;
714 error = handlers[i].gfd_fn(sb, dkeys, &info);
715 if (error)
716 break;
717 info.gfi_next_fsblk = 0;
720 head->fmh_oflags = FMH_OF_DEV_T;
721 return error;