Line data Source code
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. */
16 0 : void ext4_fsmap_from_internal(struct super_block *sb, struct fsmap *dest,
17 : struct ext4_fsmap *src)
18 : {
19 0 : dest->fmr_device = src->fmr_device;
20 0 : dest->fmr_flags = src->fmr_flags;
21 0 : dest->fmr_physical = src->fmr_physical << sb->s_blocksize_bits;
22 0 : dest->fmr_owner = src->fmr_owner;
23 0 : dest->fmr_offset = 0;
24 0 : dest->fmr_length = src->fmr_length << sb->s_blocksize_bits;
25 0 : dest->fmr_reserved[0] = 0;
26 0 : dest->fmr_reserved[1] = 0;
27 0 : dest->fmr_reserved[2] = 0;
28 0 : }
29 :
30 : /* Convert an fsmap to an ext4_fsmap. */
31 0 : void ext4_fsmap_to_internal(struct super_block *sb, struct ext4_fsmap *dest,
32 : struct fsmap *src)
33 : {
34 0 : dest->fmr_device = src->fmr_device;
35 0 : dest->fmr_flags = src->fmr_flags;
36 0 : dest->fmr_physical = src->fmr_physical >> sb->s_blocksize_bits;
37 0 : dest->fmr_owner = src->fmr_owner;
38 0 : dest->fmr_length = src->fmr_length >> sb->s_blocksize_bits;
39 0 : }
40 :
41 : /* getfsmap query state */
42 : struct 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. */
57 : struct 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. */
65 0 : static int ext4_getfsmap_dev_compare(const void *p1, const void *p2)
66 : {
67 0 : const struct ext4_getfsmap_dev *d1 = p1;
68 0 : const struct ext4_getfsmap_dev *d2 = p2;
69 :
70 0 : return d1->gfd_dev - d2->gfd_dev;
71 : }
72 :
73 : /* Compare a record against our starting point */
74 0 : static bool ext4_getfsmap_rec_before_low_key(struct ext4_getfsmap_info *info,
75 : struct ext4_fsmap *rec)
76 : {
77 0 : 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 : */
84 0 : static int ext4_getfsmap_helper(struct super_block *sb,
85 : struct ext4_getfsmap_info *info,
86 : struct ext4_fsmap *rec)
87 : {
88 0 : struct ext4_fsmap fmr;
89 0 : struct ext4_sb_info *sbi = EXT4_SB(sb);
90 0 : ext4_fsblk_t rec_fsblk = rec->fmr_physical;
91 0 : ext4_group_t agno;
92 0 : ext4_grpblk_t cno;
93 0 : int error;
94 :
95 0 : 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 0 : if (ext4_getfsmap_rec_before_low_key(info, rec)) {
103 0 : rec_fsblk += rec->fmr_length;
104 0 : if (info->gfi_next_fsblk < rec_fsblk)
105 0 : info->gfi_next_fsblk = rec_fsblk;
106 0 : return EXT4_QUERY_RANGE_CONTINUE;
107 : }
108 :
109 : /* Are we just counting mappings? */
110 0 : if (info->gfi_head->fmh_count == 0) {
111 0 : if (info->gfi_head->fmh_entries == UINT_MAX)
112 : return EXT4_QUERY_RANGE_ABORT;
113 :
114 0 : if (rec_fsblk > info->gfi_next_fsblk)
115 0 : info->gfi_head->fmh_entries++;
116 :
117 0 : if (info->gfi_last)
118 : return EXT4_QUERY_RANGE_CONTINUE;
119 :
120 0 : info->gfi_head->fmh_entries++;
121 :
122 0 : rec_fsblk += rec->fmr_length;
123 0 : if (info->gfi_next_fsblk < rec_fsblk)
124 0 : info->gfi_next_fsblk = rec_fsblk;
125 0 : return EXT4_QUERY_RANGE_CONTINUE;
126 : }
127 :
128 : /*
129 : * If the record starts past the last physical block we saw,
130 : * then we've found a gap. Report the gap as being owned by
131 : * whatever the caller specified is the missing owner.
132 : */
133 0 : if (rec_fsblk > info->gfi_next_fsblk) {
134 0 : if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count)
135 : return EXT4_QUERY_RANGE_ABORT;
136 :
137 0 : ext4_get_group_no_and_offset(sb, info->gfi_next_fsblk,
138 : &agno, &cno);
139 0 : trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno,
140 0 : EXT4_C2B(sbi, cno),
141 0 : rec_fsblk - info->gfi_next_fsblk,
142 : EXT4_FMR_OWN_UNKNOWN);
143 :
144 0 : fmr.fmr_device = info->gfi_dev;
145 0 : fmr.fmr_physical = info->gfi_next_fsblk;
146 0 : fmr.fmr_owner = EXT4_FMR_OWN_UNKNOWN;
147 0 : fmr.fmr_length = rec_fsblk - info->gfi_next_fsblk;
148 0 : fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
149 0 : error = info->gfi_formatter(&fmr, info->gfi_format_arg);
150 0 : if (error)
151 : return error;
152 0 : info->gfi_head->fmh_entries++;
153 : }
154 :
155 0 : if (info->gfi_last)
156 0 : goto out;
157 :
158 : /* Fill out the extent we found */
159 0 : if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count)
160 : return EXT4_QUERY_RANGE_ABORT;
161 :
162 0 : ext4_get_group_no_and_offset(sb, rec_fsblk, &agno, &cno);
163 0 : trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno, EXT4_C2B(sbi, cno),
164 : rec->fmr_length, rec->fmr_owner);
165 :
166 0 : fmr.fmr_device = info->gfi_dev;
167 0 : fmr.fmr_physical = rec_fsblk;
168 0 : fmr.fmr_owner = rec->fmr_owner;
169 0 : fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
170 0 : fmr.fmr_length = rec->fmr_length;
171 0 : error = info->gfi_formatter(&fmr, info->gfi_format_arg);
172 0 : if (error)
173 : return error;
174 0 : info->gfi_head->fmh_entries++;
175 :
176 0 : out:
177 0 : rec_fsblk += rec->fmr_length;
178 0 : if (info->gfi_next_fsblk < rec_fsblk)
179 0 : info->gfi_next_fsblk = rec_fsblk;
180 : return EXT4_QUERY_RANGE_CONTINUE;
181 : }
182 :
183 0 : static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr)
184 : {
185 0 : return fmr->fmr_physical + fmr->fmr_length;
186 : }
187 :
188 : /* Transform a blockgroup's free record into a fsmap */
189 0 : static int ext4_getfsmap_datadev_helper(struct super_block *sb,
190 : ext4_group_t agno, ext4_grpblk_t start,
191 : ext4_grpblk_t len, void *priv)
192 : {
193 0 : struct ext4_fsmap irec;
194 0 : struct ext4_getfsmap_info *info = priv;
195 0 : struct ext4_fsmap *p;
196 0 : struct ext4_fsmap *tmp;
197 0 : struct ext4_sb_info *sbi = EXT4_SB(sb);
198 0 : ext4_fsblk_t fsb;
199 0 : ext4_fsblk_t fslen;
200 0 : int error;
201 :
202 0 : fsb = (EXT4_C2B(sbi, start) + ext4_group_first_block_no(sb, agno));
203 0 : fslen = EXT4_C2B(sbi, len);
204 :
205 : /* If the retained free extent record is set... */
206 0 : if (info->gfi_lastfree.fmr_owner) {
207 : /* ...and abuts this one, lengthen it and return. */
208 0 : if (ext4_fsmap_next_pblk(&info->gfi_lastfree) == fsb) {
209 0 : info->gfi_lastfree.fmr_length += fslen;
210 0 : return 0;
211 : }
212 :
213 : /*
214 : * There's a gap between the two free extents; emit the
215 : * retained extent prior to merging the meta_list.
216 : */
217 0 : error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree);
218 0 : if (error)
219 : return error;
220 0 : info->gfi_lastfree.fmr_owner = 0;
221 : }
222 :
223 : /* Merge in any relevant extents from the meta_list */
224 0 : list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) {
225 0 : if (p->fmr_physical + p->fmr_length <= info->gfi_next_fsblk) {
226 0 : list_del(&p->fmr_list);
227 0 : kfree(p);
228 0 : } else if (p->fmr_physical < fsb) {
229 0 : error = ext4_getfsmap_helper(sb, info, p);
230 0 : if (error)
231 0 : return error;
232 :
233 0 : list_del(&p->fmr_list);
234 0 : kfree(p);
235 : }
236 : }
237 :
238 0 : irec.fmr_device = 0;
239 0 : irec.fmr_physical = fsb;
240 0 : irec.fmr_length = fslen;
241 0 : irec.fmr_owner = EXT4_FMR_OWN_FREE;
242 0 : irec.fmr_flags = 0;
243 :
244 : /* If this is a free extent at the end of a bg, buffer it. */
245 0 : if (ext4_fsmap_next_pblk(&irec) ==
246 0 : ext4_group_first_block_no(sb, agno + 1)) {
247 0 : info->gfi_lastfree = irec;
248 0 : return 0;
249 : }
250 :
251 : /* Otherwise, emit it */
252 0 : return ext4_getfsmap_helper(sb, info, &irec);
253 : }
254 :
255 : /* Execute a getfsmap query against the log device. */
256 0 : static int ext4_getfsmap_logdev(struct super_block *sb, struct ext4_fsmap *keys,
257 : struct ext4_getfsmap_info *info)
258 : {
259 0 : journal_t *journal = EXT4_SB(sb)->s_journal;
260 0 : struct ext4_fsmap irec;
261 :
262 : /* Set up search keys */
263 0 : info->gfi_low = keys[0];
264 0 : info->gfi_low.fmr_length = 0;
265 :
266 0 : memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high));
267 :
268 0 : trace_ext4_fsmap_low_key(sb, info->gfi_dev, 0,
269 : info->gfi_low.fmr_physical,
270 : info->gfi_low.fmr_length,
271 : info->gfi_low.fmr_owner);
272 :
273 0 : trace_ext4_fsmap_high_key(sb, info->gfi_dev, 0,
274 : info->gfi_high.fmr_physical,
275 : info->gfi_high.fmr_length,
276 : info->gfi_high.fmr_owner);
277 :
278 0 : if (keys[0].fmr_physical > 0)
279 : return 0;
280 :
281 : /* Fabricate an rmap entry for the external log device. */
282 0 : irec.fmr_physical = journal->j_blk_offset;
283 0 : irec.fmr_length = journal->j_total_len;
284 0 : irec.fmr_owner = EXT4_FMR_OWN_LOG;
285 0 : irec.fmr_flags = 0;
286 :
287 0 : return ext4_getfsmap_helper(sb, info, &irec);
288 : }
289 :
290 : /* Helper to fill out an ext4_fsmap. */
291 0 : static inline int ext4_getfsmap_fill(struct list_head *meta_list,
292 : ext4_fsblk_t fsb, ext4_fsblk_t len,
293 : uint64_t owner)
294 : {
295 0 : struct ext4_fsmap *fsm;
296 :
297 0 : fsm = kmalloc(sizeof(*fsm), GFP_NOFS);
298 0 : if (!fsm)
299 : return -ENOMEM;
300 0 : fsm->fmr_device = 0;
301 0 : fsm->fmr_flags = 0;
302 0 : fsm->fmr_physical = fsb;
303 0 : fsm->fmr_owner = owner;
304 0 : fsm->fmr_length = len;
305 0 : list_add_tail(&fsm->fmr_list, meta_list);
306 :
307 0 : return 0;
308 : }
309 :
310 : /*
311 : * This function returns the number of file system metadata blocks at
312 : * the beginning of a block group, including the reserved gdt blocks.
313 : */
314 0 : static unsigned int ext4_getfsmap_find_sb(struct super_block *sb,
315 : ext4_group_t agno,
316 : struct list_head *meta_list)
317 : {
318 0 : struct ext4_sb_info *sbi = EXT4_SB(sb);
319 0 : ext4_fsblk_t fsb = ext4_group_first_block_no(sb, agno);
320 0 : ext4_fsblk_t len;
321 0 : unsigned long first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
322 0 : unsigned long metagroup = agno / EXT4_DESC_PER_BLOCK(sb);
323 0 : int error;
324 :
325 : /* Record the superblock. */
326 0 : if (ext4_bg_has_super(sb, agno)) {
327 0 : error = ext4_getfsmap_fill(meta_list, fsb, 1, EXT4_FMR_OWN_FS);
328 0 : if (error)
329 0 : return error;
330 0 : fsb++;
331 : }
332 :
333 : /* Record the group descriptors. */
334 0 : len = ext4_bg_num_gdb(sb, agno);
335 0 : if (!len)
336 : return 0;
337 0 : error = ext4_getfsmap_fill(meta_list, fsb, len,
338 : EXT4_FMR_OWN_GDT);
339 0 : if (error)
340 0 : return error;
341 0 : fsb += len;
342 :
343 : /* Reserved GDT blocks */
344 0 : if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) {
345 0 : len = le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
346 0 : error = ext4_getfsmap_fill(meta_list, fsb, len,
347 : EXT4_FMR_OWN_RESV_GDT);
348 0 : if (error)
349 0 : return error;
350 : }
351 :
352 : return 0;
353 : }
354 :
355 : /* Compare two fsmap items. */
356 0 : static int ext4_getfsmap_compare(void *priv,
357 : struct list_head *a,
358 : struct list_head *b)
359 : {
360 0 : struct ext4_fsmap *fa;
361 0 : struct ext4_fsmap *fb;
362 :
363 0 : fa = container_of(a, struct ext4_fsmap, fmr_list);
364 0 : fb = container_of(b, struct ext4_fsmap, fmr_list);
365 0 : if (fa->fmr_physical < fb->fmr_physical)
366 : return -1;
367 0 : else if (fa->fmr_physical > fb->fmr_physical)
368 0 : return 1;
369 : return 0;
370 : }
371 :
372 : /* Merge adjacent extents of fixed metadata. */
373 0 : static void ext4_getfsmap_merge_fixed_metadata(struct list_head *meta_list)
374 : {
375 0 : struct ext4_fsmap *p;
376 0 : struct ext4_fsmap *prev = NULL;
377 0 : struct ext4_fsmap *tmp;
378 :
379 0 : list_for_each_entry_safe(p, tmp, meta_list, fmr_list) {
380 0 : if (!prev) {
381 0 : prev = p;
382 0 : continue;
383 : }
384 :
385 0 : if (prev->fmr_owner == p->fmr_owner &&
386 0 : prev->fmr_physical + prev->fmr_length == p->fmr_physical) {
387 0 : prev->fmr_length += p->fmr_length;
388 0 : list_del(&p->fmr_list);
389 0 : kfree(p);
390 : } else
391 : prev = p;
392 : }
393 0 : }
394 :
395 : /* Free a list of fixed metadata. */
396 0 : static void ext4_getfsmap_free_fixed_metadata(struct list_head *meta_list)
397 : {
398 0 : struct ext4_fsmap *p;
399 0 : struct ext4_fsmap *tmp;
400 :
401 0 : list_for_each_entry_safe(p, tmp, meta_list, fmr_list) {
402 0 : list_del(&p->fmr_list);
403 0 : kfree(p);
404 : }
405 0 : }
406 :
407 : /* Find all the fixed metadata in the filesystem. */
408 0 : static int ext4_getfsmap_find_fixed_metadata(struct super_block *sb,
409 : struct list_head *meta_list)
410 : {
411 0 : struct ext4_group_desc *gdp;
412 0 : ext4_group_t agno;
413 0 : int error;
414 :
415 0 : INIT_LIST_HEAD(meta_list);
416 :
417 : /* Collect everything. */
418 0 : for (agno = 0; agno < EXT4_SB(sb)->s_groups_count; agno++) {
419 0 : gdp = ext4_get_group_desc(sb, agno, NULL);
420 0 : if (!gdp) {
421 0 : error = -EFSCORRUPTED;
422 0 : goto err;
423 : }
424 :
425 : /* Superblock & GDT */
426 0 : error = ext4_getfsmap_find_sb(sb, agno, meta_list);
427 0 : if (error)
428 0 : goto err;
429 :
430 : /* Block bitmap */
431 0 : error = ext4_getfsmap_fill(meta_list,
432 : ext4_block_bitmap(sb, gdp), 1,
433 : EXT4_FMR_OWN_BLKBM);
434 0 : if (error)
435 0 : goto err;
436 :
437 : /* Inode bitmap */
438 0 : error = ext4_getfsmap_fill(meta_list,
439 : ext4_inode_bitmap(sb, gdp), 1,
440 : EXT4_FMR_OWN_INOBM);
441 0 : if (error)
442 0 : goto err;
443 :
444 : /* Inodes */
445 0 : error = ext4_getfsmap_fill(meta_list,
446 : ext4_inode_table(sb, gdp),
447 0 : EXT4_SB(sb)->s_itb_per_group,
448 : EXT4_FMR_OWN_INODES);
449 0 : if (error)
450 0 : goto err;
451 : }
452 :
453 : /* Sort the list */
454 0 : list_sort(NULL, meta_list, ext4_getfsmap_compare);
455 :
456 : /* Merge adjacent extents */
457 0 : ext4_getfsmap_merge_fixed_metadata(meta_list);
458 :
459 0 : return 0;
460 0 : err:
461 0 : ext4_getfsmap_free_fixed_metadata(meta_list);
462 0 : return error;
463 : }
464 :
465 : /* Execute a getfsmap query against the buddy bitmaps */
466 0 : static int ext4_getfsmap_datadev(struct super_block *sb,
467 : struct ext4_fsmap *keys,
468 : struct ext4_getfsmap_info *info)
469 : {
470 0 : struct ext4_sb_info *sbi = EXT4_SB(sb);
471 0 : ext4_fsblk_t start_fsb;
472 0 : ext4_fsblk_t end_fsb;
473 0 : ext4_fsblk_t bofs;
474 0 : ext4_fsblk_t eofs;
475 0 : ext4_group_t start_ag;
476 0 : ext4_group_t end_ag;
477 0 : ext4_grpblk_t first_cluster;
478 0 : ext4_grpblk_t last_cluster;
479 0 : int error = 0;
480 :
481 0 : bofs = le32_to_cpu(sbi->s_es->s_first_data_block);
482 0 : eofs = ext4_blocks_count(sbi->s_es);
483 0 : if (keys[0].fmr_physical >= eofs)
484 : return 0;
485 0 : else if (keys[0].fmr_physical < bofs)
486 0 : keys[0].fmr_physical = bofs;
487 0 : if (keys[1].fmr_physical >= eofs)
488 0 : keys[1].fmr_physical = eofs - 1;
489 0 : start_fsb = keys[0].fmr_physical;
490 0 : end_fsb = keys[1].fmr_physical;
491 :
492 : /* Determine first and last group to examine based on start and end */
493 0 : ext4_get_group_no_and_offset(sb, start_fsb, &start_ag, &first_cluster);
494 0 : ext4_get_group_no_and_offset(sb, end_fsb, &end_ag, &last_cluster);
495 :
496 : /*
497 : * Convert the fsmap low/high keys to bg based keys. Initialize
498 : * low to the fsmap low key and max out the high key to the end
499 : * of the bg.
500 : */
501 0 : info->gfi_low = keys[0];
502 0 : info->gfi_low.fmr_physical = EXT4_C2B(sbi, first_cluster);
503 0 : info->gfi_low.fmr_length = 0;
504 :
505 0 : memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high));
506 :
507 : /* Assemble a list of all the fixed-location metadata. */
508 0 : error = ext4_getfsmap_find_fixed_metadata(sb, &info->gfi_meta_list);
509 0 : if (error)
510 0 : goto err;
511 :
512 : /* Query each bg */
513 0 : for (info->gfi_agno = start_ag;
514 0 : info->gfi_agno <= end_ag;
515 0 : info->gfi_agno++) {
516 : /*
517 : * Set the bg high key from the fsmap high key if this
518 : * is the last bg that we're querying.
519 : */
520 0 : if (info->gfi_agno == end_ag) {
521 0 : info->gfi_high = keys[1];
522 0 : info->gfi_high.fmr_physical = EXT4_C2B(sbi,
523 : last_cluster);
524 0 : info->gfi_high.fmr_length = 0;
525 : }
526 :
527 0 : trace_ext4_fsmap_low_key(sb, info->gfi_dev, info->gfi_agno,
528 : info->gfi_low.fmr_physical,
529 : info->gfi_low.fmr_length,
530 : info->gfi_low.fmr_owner);
531 :
532 0 : trace_ext4_fsmap_high_key(sb, info->gfi_dev, info->gfi_agno,
533 : info->gfi_high.fmr_physical,
534 : info->gfi_high.fmr_length,
535 : info->gfi_high.fmr_owner);
536 :
537 0 : error = ext4_mballoc_query_range(sb, info->gfi_agno,
538 0 : EXT4_B2C(sbi, info->gfi_low.fmr_physical),
539 0 : EXT4_B2C(sbi, info->gfi_high.fmr_physical),
540 : ext4_getfsmap_datadev_helper, info);
541 0 : if (error)
542 0 : goto err;
543 :
544 : /*
545 : * Set the bg low key to the start of the bg prior to
546 : * moving on to the next bg.
547 : */
548 0 : if (info->gfi_agno == start_ag)
549 0 : memset(&info->gfi_low, 0, sizeof(info->gfi_low));
550 : }
551 :
552 : /* Do we have a retained free extent? */
553 0 : if (info->gfi_lastfree.fmr_owner) {
554 0 : error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree);
555 0 : if (error)
556 0 : goto err;
557 : }
558 :
559 : /* Report any gaps at the end of the bg */
560 0 : info->gfi_last = true;
561 0 : error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster, 0, info);
562 0 : if (error)
563 0 : goto err;
564 :
565 0 : err:
566 0 : ext4_getfsmap_free_fixed_metadata(&info->gfi_meta_list);
567 0 : return error;
568 : }
569 :
570 : /* Do we recognize the device? */
571 0 : static bool ext4_getfsmap_is_valid_device(struct super_block *sb,
572 : struct ext4_fsmap *fm)
573 : {
574 0 : if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX ||
575 0 : fm->fmr_device == new_encode_dev(sb->s_bdev->bd_dev))
576 : return true;
577 0 : if (EXT4_SB(sb)->s_journal_bdev &&
578 0 : fm->fmr_device == new_encode_dev(EXT4_SB(sb)->s_journal_bdev->bd_dev))
579 0 : return true;
580 : return false;
581 : }
582 :
583 : /* Ensure that the low key is less than the high key. */
584 0 : static bool ext4_getfsmap_check_keys(struct ext4_fsmap *low_key,
585 : struct ext4_fsmap *high_key)
586 : {
587 0 : if (low_key->fmr_device > high_key->fmr_device)
588 : return false;
589 0 : if (low_key->fmr_device < high_key->fmr_device)
590 : return true;
591 :
592 0 : if (low_key->fmr_physical > high_key->fmr_physical)
593 : return false;
594 0 : if (low_key->fmr_physical < high_key->fmr_physical)
595 : return true;
596 :
597 0 : if (low_key->fmr_owner > high_key->fmr_owner)
598 : return false;
599 0 : if (low_key->fmr_owner < high_key->fmr_owner)
600 0 : return true;
601 :
602 : return false;
603 : }
604 :
605 : #define EXT4_GETFSMAP_DEVS 2
606 : /*
607 : * Get filesystem's extents as described in head, and format for
608 : * output. Calls formatter to fill the user's buffer until all
609 : * extents are mapped, until the passed-in head->fmh_count slots have
610 : * been filled, or until the formatter short-circuits the loop, if it
611 : * is tracking filled-in extents on its own.
612 : *
613 : * Key to Confusion
614 : * ----------------
615 : * There are multiple levels of keys and counters at work here:
616 : * _fsmap_head.fmh_keys -- low and high fsmap keys passed in;
617 : * these reflect fs-wide block addrs.
618 : * dkeys -- fmh_keys used to query each device;
619 : * these are fmh_keys but w/ the low key
620 : * bumped up by fmr_length.
621 : * _getfsmap_info.gfi_next_fsblk-- next fs block we expect to see; this
622 : * is how we detect gaps in the fsmap
623 : * records and report them.
624 : * _getfsmap_info.gfi_low/high -- per-bg low/high keys computed from
625 : * dkeys; used to query the free space.
626 : */
627 0 : int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head,
628 : ext4_fsmap_format_t formatter, void *arg)
629 : {
630 0 : struct ext4_fsmap dkeys[2]; /* per-dev keys */
631 0 : struct ext4_getfsmap_dev handlers[EXT4_GETFSMAP_DEVS];
632 0 : struct ext4_getfsmap_info info = { NULL };
633 0 : int i;
634 0 : int error = 0;
635 :
636 0 : if (head->fmh_iflags & ~FMH_IF_VALID)
637 : return -EINVAL;
638 0 : if (!ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[0]) ||
639 0 : !ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[1]))
640 : return -EINVAL;
641 :
642 0 : head->fmh_entries = 0;
643 :
644 : /* Set up our device handlers. */
645 0 : memset(handlers, 0, sizeof(handlers));
646 0 : handlers[0].gfd_dev = new_encode_dev(sb->s_bdev->bd_dev);
647 0 : handlers[0].gfd_fn = ext4_getfsmap_datadev;
648 0 : if (EXT4_SB(sb)->s_journal_bdev) {
649 0 : handlers[1].gfd_dev = new_encode_dev(
650 0 : EXT4_SB(sb)->s_journal_bdev->bd_dev);
651 0 : handlers[1].gfd_fn = ext4_getfsmap_logdev;
652 : }
653 :
654 0 : sort(handlers, EXT4_GETFSMAP_DEVS, sizeof(struct ext4_getfsmap_dev),
655 : ext4_getfsmap_dev_compare, NULL);
656 :
657 : /*
658 : * To continue where we left off, we allow userspace to use the
659 : * last mapping from a previous call as the low key of the next.
660 : * This is identified by a non-zero length in the low key. We
661 : * have to increment the low key in this scenario to ensure we
662 : * don't return the same mapping again, and instead return the
663 : * very next mapping.
664 : *
665 : * Bump the physical offset as there can be no other mapping for
666 : * the same physical block range.
667 : */
668 0 : dkeys[0] = head->fmh_keys[0];
669 0 : dkeys[0].fmr_physical += dkeys[0].fmr_length;
670 0 : dkeys[0].fmr_owner = 0;
671 0 : dkeys[0].fmr_length = 0;
672 0 : memset(&dkeys[1], 0xFF, sizeof(struct ext4_fsmap));
673 :
674 0 : if (!ext4_getfsmap_check_keys(dkeys, &head->fmh_keys[1]))
675 : return -EINVAL;
676 :
677 0 : info.gfi_next_fsblk = head->fmh_keys[0].fmr_physical +
678 0 : head->fmh_keys[0].fmr_length;
679 0 : info.gfi_formatter = formatter;
680 0 : info.gfi_format_arg = arg;
681 0 : info.gfi_head = head;
682 :
683 : /* For each device we support... */
684 0 : for (i = 0; i < EXT4_GETFSMAP_DEVS; i++) {
685 : /* Is this device within the range the user asked for? */
686 0 : if (!handlers[i].gfd_fn)
687 0 : continue;
688 0 : if (head->fmh_keys[0].fmr_device > handlers[i].gfd_dev)
689 0 : continue;
690 0 : if (head->fmh_keys[1].fmr_device < handlers[i].gfd_dev)
691 : break;
692 :
693 : /*
694 : * If this device number matches the high key, we have
695 : * to pass the high key to the handler to limit the
696 : * query results. If the device number exceeds the
697 : * low key, zero out the low key so that we get
698 : * everything from the beginning.
699 : */
700 0 : if (handlers[i].gfd_dev == head->fmh_keys[1].fmr_device)
701 0 : dkeys[1] = head->fmh_keys[1];
702 0 : if (handlers[i].gfd_dev > head->fmh_keys[0].fmr_device)
703 0 : memset(&dkeys[0], 0, sizeof(struct ext4_fsmap));
704 :
705 0 : info.gfi_dev = handlers[i].gfd_dev;
706 0 : info.gfi_last = false;
707 0 : info.gfi_agno = -1;
708 0 : error = handlers[i].gfd_fn(sb, dkeys, &info);
709 0 : if (error)
710 : break;
711 0 : info.gfi_next_fsblk = 0;
712 : }
713 :
714 0 : head->fmh_oflags = FMH_OF_DEV_T;
715 0 : return error;
716 : }
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