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 | void 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. */ |
31 | void 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 */ |
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 | static 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 */ |
74 | static 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 | */ |
84 | static 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 (info->gfi_head->fmh_entries == UINT_MAX) |
112 | return EXT4_QUERY_RANGE_ABORT; |
113 | |
114 | if (rec_fsblk > info->gfi_next_fsblk) |
115 | info->gfi_head->fmh_entries++; |
116 | |
117 | if (info->gfi_last) |
118 | return EXT4_QUERY_RANGE_CONTINUE; |
119 | |
120 | info->gfi_head->fmh_entries++; |
121 | |
122 | rec_fsblk += rec->fmr_length; |
123 | if (info->gfi_next_fsblk < rec_fsblk) |
124 | info->gfi_next_fsblk = rec_fsblk; |
125 | 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 | if (rec_fsblk > info->gfi_next_fsblk) { |
134 | if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count) |
135 | return EXT4_QUERY_RANGE_ABORT; |
136 | |
137 | ext4_get_group_no_and_offset(sb, blocknr: info->gfi_next_fsblk, |
138 | blockgrpp: &agno, offsetp: &cno); |
139 | trace_ext4_fsmap_mapping(sb, keydev: info->gfi_dev, agno, |
140 | EXT4_C2B(sbi, cno), |
141 | len: rec_fsblk - info->gfi_next_fsblk, |
142 | EXT4_FMR_OWN_UNKNOWN); |
143 | |
144 | fmr.fmr_device = info->gfi_dev; |
145 | fmr.fmr_physical = info->gfi_next_fsblk; |
146 | fmr.fmr_owner = EXT4_FMR_OWN_UNKNOWN; |
147 | fmr.fmr_length = rec_fsblk - info->gfi_next_fsblk; |
148 | fmr.fmr_flags = FMR_OF_SPECIAL_OWNER; |
149 | error = info->gfi_formatter(&fmr, info->gfi_format_arg); |
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 >= info->gfi_head->fmh_count) |
160 | return EXT4_QUERY_RANGE_ABORT; |
161 | |
162 | ext4_get_group_no_and_offset(sb, blocknr: rec_fsblk, blockgrpp: &agno, offsetp: &cno); |
163 | trace_ext4_fsmap_mapping(sb, keydev: info->gfi_dev, agno, EXT4_C2B(sbi, cno), |
164 | len: rec->fmr_length, owner: rec->fmr_owner); |
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->gfi_format_arg); |
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_fsblk; |
180 | return EXT4_QUERY_RANGE_CONTINUE; |
181 | } |
182 | |
183 | static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr) |
184 | { |
185 | return fmr->fmr_physical + fmr->fmr_length; |
186 | } |
187 | |
188 | /* Transform a blockgroup's free record into a fsmap */ |
189 | 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 | 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_group_first_block_no(sb, group_no: agno)); |
203 | fslen = EXT4_C2B(sbi, len); |
204 | |
205 | /* If the retained free extent record is set... */ |
206 | if (info->gfi_lastfree.fmr_owner) { |
207 | /* ...and abuts this one, lengthen it and return. */ |
208 | if (ext4_fsmap_next_pblk(fmr: &info->gfi_lastfree) == fsb) { |
209 | info->gfi_lastfree.fmr_length += fslen; |
210 | 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 | error = ext4_getfsmap_helper(sb, info, rec: &info->gfi_lastfree); |
218 | if (error) |
219 | return error; |
220 | info->gfi_lastfree.fmr_owner = 0; |
221 | } |
222 | |
223 | /* Merge in any relevant extents from the meta_list */ |
224 | list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) { |
225 | if (p->fmr_physical + p->fmr_length <= info->gfi_next_fsblk) { |
226 | list_del(entry: &p->fmr_list); |
227 | kfree(objp: p); |
228 | } else if (p->fmr_physical < fsb) { |
229 | error = ext4_getfsmap_helper(sb, info, rec: p); |
230 | if (error) |
231 | return error; |
232 | |
233 | list_del(entry: &p->fmr_list); |
234 | kfree(objp: 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 of a bg, buffer it. */ |
245 | if (ext4_fsmap_next_pblk(fmr: &irec) == |
246 | ext4_group_first_block_no(sb, group_no: agno + 1)) { |
247 | info->gfi_lastfree = irec; |
248 | return 0; |
249 | } |
250 | |
251 | /* Otherwise, emit it */ |
252 | return ext4_getfsmap_helper(sb, info, rec: &irec); |
253 | } |
254 | |
255 | /* Execute a getfsmap query against the log device. */ |
256 | static int ext4_getfsmap_logdev(struct super_block *sb, struct ext4_fsmap *keys, |
257 | struct ext4_getfsmap_info *info) |
258 | { |
259 | journal_t *journal = EXT4_SB(sb)->s_journal; |
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(info->gfi_high)); |
267 | |
268 | trace_ext4_fsmap_low_key(sb, keydev: info->gfi_dev, agno: 0, |
269 | bno: info->gfi_low.fmr_physical, |
270 | len: info->gfi_low.fmr_length, |
271 | owner: info->gfi_low.fmr_owner); |
272 | |
273 | trace_ext4_fsmap_high_key(sb, keydev: info->gfi_dev, agno: 0, |
274 | bno: info->gfi_high.fmr_physical, |
275 | len: info->gfi_high.fmr_length, |
276 | owner: info->gfi_high.fmr_owner); |
277 | |
278 | if (keys[0].fmr_physical > 0) |
279 | return 0; |
280 | |
281 | /* Fabricate an rmap entry for the external log device. */ |
282 | irec.fmr_physical = journal->j_blk_offset; |
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, rec: &irec); |
288 | } |
289 | |
290 | /* Helper to fill out an ext4_fsmap. */ |
291 | 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 | struct ext4_fsmap *fsm; |
296 | |
297 | fsm = kmalloc(size: 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(new: &fsm->fmr_list, head: meta_list); |
306 | |
307 | 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 | static unsigned int ext4_getfsmap_find_sb(struct super_block *sb, |
315 | ext4_group_t agno, |
316 | struct list_head *meta_list) |
317 | { |
318 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
319 | ext4_fsblk_t fsb = ext4_group_first_block_no(sb, group_no: agno); |
320 | ext4_fsblk_t len; |
321 | unsigned long first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg); |
322 | unsigned long metagroup = agno / EXT4_DESC_PER_BLOCK(sb); |
323 | int error; |
324 | |
325 | /* Record the superblock. */ |
326 | if (ext4_bg_has_super(sb, group: agno)) { |
327 | error = ext4_getfsmap_fill(meta_list, fsb, len: 1, EXT4_FMR_OWN_FS); |
328 | if (error) |
329 | return error; |
330 | fsb++; |
331 | } |
332 | |
333 | /* Record the group descriptors. */ |
334 | len = ext4_bg_num_gdb(sb, group: agno); |
335 | if (!len) |
336 | return 0; |
337 | error = ext4_getfsmap_fill(meta_list, fsb, len, |
338 | EXT4_FMR_OWN_GDT); |
339 | if (error) |
340 | return error; |
341 | fsb += len; |
342 | |
343 | /* Reserved GDT blocks */ |
344 | if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) { |
345 | len = le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); |
346 | error = ext4_getfsmap_fill(meta_list, fsb, len, |
347 | EXT4_FMR_OWN_RESV_GDT); |
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 list_head *a, |
358 | const struct list_head *b) |
359 | { |
360 | struct ext4_fsmap *fa; |
361 | struct ext4_fsmap *fb; |
362 | |
363 | fa = container_of(a, struct ext4_fsmap, fmr_list); |
364 | fb = container_of(b, struct ext4_fsmap, fmr_list); |
365 | if (fa->fmr_physical < fb->fmr_physical) |
366 | return -1; |
367 | else if (fa->fmr_physical > fb->fmr_physical) |
368 | return 1; |
369 | return 0; |
370 | } |
371 | |
372 | /* Merge adjacent extents of fixed metadata. */ |
373 | static void ext4_getfsmap_merge_fixed_metadata(struct list_head *meta_list) |
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_list, fmr_list) { |
380 | if (!prev) { |
381 | prev = p; |
382 | continue; |
383 | } |
384 | |
385 | if (prev->fmr_owner == p->fmr_owner && |
386 | prev->fmr_physical + prev->fmr_length == p->fmr_physical) { |
387 | prev->fmr_length += p->fmr_length; |
388 | list_del(entry: &p->fmr_list); |
389 | kfree(objp: p); |
390 | } else |
391 | prev = p; |
392 | } |
393 | } |
394 | |
395 | /* Free a list of fixed metadata. */ |
396 | static void ext4_getfsmap_free_fixed_metadata(struct list_head *meta_list) |
397 | { |
398 | struct ext4_fsmap *p; |
399 | struct ext4_fsmap *tmp; |
400 | |
401 | list_for_each_entry_safe(p, tmp, meta_list, fmr_list) { |
402 | list_del(entry: &p->fmr_list); |
403 | kfree(objp: p); |
404 | } |
405 | } |
406 | |
407 | /* Find all the fixed metadata in the filesystem. */ |
408 | static int ext4_getfsmap_find_fixed_metadata(struct super_block *sb, |
409 | struct list_head *meta_list) |
410 | { |
411 | struct ext4_group_desc *gdp; |
412 | ext4_group_t agno; |
413 | int error; |
414 | |
415 | INIT_LIST_HEAD(list: meta_list); |
416 | |
417 | /* Collect everything. */ |
418 | for (agno = 0; agno < EXT4_SB(sb)->s_groups_count; agno++) { |
419 | gdp = ext4_get_group_desc(sb, block_group: agno, NULL); |
420 | if (!gdp) { |
421 | error = -EFSCORRUPTED; |
422 | goto err; |
423 | } |
424 | |
425 | /* Superblock & GDT */ |
426 | error = ext4_getfsmap_find_sb(sb, agno, meta_list); |
427 | if (error) |
428 | goto err; |
429 | |
430 | /* Block bitmap */ |
431 | error = ext4_getfsmap_fill(meta_list, |
432 | fsb: ext4_block_bitmap(sb, bg: gdp), len: 1, |
433 | EXT4_FMR_OWN_BLKBM); |
434 | if (error) |
435 | goto err; |
436 | |
437 | /* Inode bitmap */ |
438 | error = ext4_getfsmap_fill(meta_list, |
439 | fsb: ext4_inode_bitmap(sb, bg: gdp), len: 1, |
440 | EXT4_FMR_OWN_INOBM); |
441 | if (error) |
442 | goto err; |
443 | |
444 | /* Inodes */ |
445 | error = ext4_getfsmap_fill(meta_list, |
446 | fsb: ext4_inode_table(sb, bg: gdp), |
447 | len: EXT4_SB(sb)->s_itb_per_group, |
448 | EXT4_FMR_OWN_INODES); |
449 | if (error) |
450 | goto err; |
451 | } |
452 | |
453 | /* Sort the list */ |
454 | list_sort(NULL, head: meta_list, cmp: ext4_getfsmap_compare); |
455 | |
456 | /* Merge adjacent extents */ |
457 | ext4_getfsmap_merge_fixed_metadata(meta_list); |
458 | |
459 | return 0; |
460 | err: |
461 | ext4_getfsmap_free_fixed_metadata(meta_list); |
462 | return error; |
463 | } |
464 | |
465 | /* Execute a getfsmap query against the buddy bitmaps */ |
466 | static int ext4_getfsmap_datadev(struct super_block *sb, |
467 | struct ext4_fsmap *keys, |
468 | struct ext4_getfsmap_info *info) |
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_data_block); |
482 | eofs = ext4_blocks_count(es: 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 - 1; |
489 | if (keys[1].fmr_physical < keys[0].fmr_physical) |
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 examine based on start and end */ |
495 | ext4_get_group_no_and_offset(sb, blocknr: start_fsb, blockgrpp: &start_ag, offsetp: &first_cluster); |
496 | ext4_get_group_no_and_offset(sb, blocknr: end_fsb, blockgrpp: &end_ag, offsetp: &last_cluster); |
497 | |
498 | /* |
499 | * Convert the fsmap low/high keys to bg based keys. Initialize |
500 | * low to the fsmap low key and max out the high key to the end |
501 | * of the bg. |
502 | */ |
503 | info->gfi_low = keys[0]; |
504 | info->gfi_low.fmr_physical = EXT4_C2B(sbi, first_cluster); |
505 | info->gfi_low.fmr_length = 0; |
506 | |
507 | memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high)); |
508 | |
509 | /* Assemble a list of all the fixed-location metadata. */ |
510 | error = ext4_getfsmap_find_fixed_metadata(sb, meta_list: &info->gfi_meta_list); |
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 the fsmap high key if this |
520 | * is the last bg that we're querying. |
521 | */ |
522 | if (info->gfi_agno == end_ag) { |
523 | info->gfi_high = keys[1]; |
524 | info->gfi_high.fmr_physical = EXT4_C2B(sbi, |
525 | last_cluster); |
526 | info->gfi_high.fmr_length = 0; |
527 | } |
528 | |
529 | trace_ext4_fsmap_low_key(sb, keydev: info->gfi_dev, agno: info->gfi_agno, |
530 | bno: info->gfi_low.fmr_physical, |
531 | len: info->gfi_low.fmr_length, |
532 | owner: info->gfi_low.fmr_owner); |
533 | |
534 | trace_ext4_fsmap_high_key(sb, keydev: info->gfi_dev, agno: info->gfi_agno, |
535 | bno: info->gfi_high.fmr_physical, |
536 | len: info->gfi_high.fmr_length, |
537 | owner: info->gfi_high.fmr_owner); |
538 | |
539 | error = ext4_mballoc_query_range(sb, agno: info->gfi_agno, |
540 | EXT4_B2C(sbi, info->gfi_low.fmr_physical), |
541 | EXT4_B2C(sbi, info->gfi_high.fmr_physical), |
542 | formatter: ext4_getfsmap_datadev_helper, priv: info); |
543 | if (error) |
544 | goto err; |
545 | |
546 | /* |
547 | * Set the bg low key to the start of the bg prior to |
548 | * moving on to the next bg. |
549 | */ |
550 | if (info->gfi_agno == start_ag) |
551 | memset(&info->gfi_low, 0, sizeof(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(sb, info, rec: &info->gfi_lastfree); |
557 | if (error) |
558 | goto err; |
559 | } |
560 | |
561 | /* Report any gaps at the end of the bg */ |
562 | info->gfi_last = true; |
563 | error = ext4_getfsmap_datadev_helper(sb, agno: end_ag, start: last_cluster, len: 0, priv: info); |
564 | if (error) |
565 | goto err; |
566 | |
567 | err: |
568 | ext4_getfsmap_free_fixed_metadata(meta_list: &info->gfi_meta_list); |
569 | return error; |
570 | } |
571 | |
572 | /* Do we recognize the device? */ |
573 | static bool ext4_getfsmap_is_valid_device(struct super_block *sb, |
574 | struct ext4_fsmap *fm) |
575 | { |
576 | if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX || |
577 | fm->fmr_device == new_encode_dev(dev: sb->s_bdev->bd_dev)) |
578 | return true; |
579 | if (EXT4_SB(sb)->s_journal_bdev_handle && |
580 | fm->fmr_device == |
581 | new_encode_dev(dev: EXT4_SB(sb)->s_journal_bdev_handle->bdev->bd_dev)) |
582 | return true; |
583 | return false; |
584 | } |
585 | |
586 | /* Ensure that the low key is less than the high key. */ |
587 | static bool ext4_getfsmap_check_keys(struct ext4_fsmap *low_key, |
588 | struct ext4_fsmap *high_key) |
589 | { |
590 | if (low_key->fmr_device > high_key->fmr_device) |
591 | return false; |
592 | if (low_key->fmr_device < high_key->fmr_device) |
593 | return true; |
594 | |
595 | if (low_key->fmr_physical > high_key->fmr_physical) |
596 | return false; |
597 | if (low_key->fmr_physical < high_key->fmr_physical) |
598 | return true; |
599 | |
600 | if (low_key->fmr_owner > high_key->fmr_owner) |
601 | return false; |
602 | if (low_key->fmr_owner < high_key->fmr_owner) |
603 | return true; |
604 | |
605 | return false; |
606 | } |
607 | |
608 | #define EXT4_GETFSMAP_DEVS 2 |
609 | /* |
610 | * Get filesystem's extents as described in head, and format for |
611 | * output. Calls formatter to fill the user's buffer until all |
612 | * extents are mapped, until the passed-in head->fmh_count slots have |
613 | * been filled, or until the formatter short-circuits the loop, if it |
614 | * is tracking filled-in extents on its own. |
615 | * |
616 | * Key to Confusion |
617 | * ---------------- |
618 | * There are multiple levels of keys and counters at work here: |
619 | * _fsmap_head.fmh_keys -- low and high fsmap keys passed in; |
620 | * these reflect fs-wide block addrs. |
621 | * dkeys -- fmh_keys used to query each device; |
622 | * these are fmh_keys but w/ the low key |
623 | * bumped up by fmr_length. |
624 | * _getfsmap_info.gfi_next_fsblk-- next fs block we expect to see; this |
625 | * is how we detect gaps in the fsmap |
626 | * records and report them. |
627 | * _getfsmap_info.gfi_low/high -- per-bg low/high keys computed from |
628 | * dkeys; used to query the free space. |
629 | */ |
630 | int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head, |
631 | ext4_fsmap_format_t formatter, void *arg) |
632 | { |
633 | struct ext4_fsmap dkeys[2]; /* per-dev keys */ |
634 | struct ext4_getfsmap_dev handlers[EXT4_GETFSMAP_DEVS]; |
635 | struct ext4_getfsmap_info info = { NULL }; |
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, fm: &head->fmh_keys[0]) || |
642 | !ext4_getfsmap_is_valid_device(sb, fm: &head->fmh_keys[1])) |
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(dev: sb->s_bdev->bd_dev); |
650 | handlers[0].gfd_fn = ext4_getfsmap_datadev; |
651 | if (EXT4_SB(sb)->s_journal_bdev_handle) { |
652 | handlers[1].gfd_dev = new_encode_dev( |
653 | dev: EXT4_SB(sb)->s_journal_bdev_handle->bdev->bd_dev); |
654 | handlers[1].gfd_fn = ext4_getfsmap_logdev; |
655 | } |
656 | |
657 | sort(base: handlers, EXT4_GETFSMAP_DEVS, size: sizeof(struct ext4_getfsmap_dev), |
658 | cmp_func: ext4_getfsmap_dev_compare, NULL); |
659 | |
660 | /* |
661 | * To continue where we left off, we allow userspace to use the |
662 | * last mapping from a previous call as the low key of the next. |
663 | * This is identified by a non-zero length in the low key. We |
664 | * have to increment the low key in this scenario to ensure we |
665 | * don't return the same mapping again, and instead return the |
666 | * very next mapping. |
667 | * |
668 | * Bump the physical offset as there can be no other mapping for |
669 | * the same physical block range. |
670 | */ |
671 | dkeys[0] = head->fmh_keys[0]; |
672 | dkeys[0].fmr_physical += dkeys[0].fmr_length; |
673 | dkeys[0].fmr_owner = 0; |
674 | dkeys[0].fmr_length = 0; |
675 | memset(&dkeys[1], 0xFF, sizeof(struct ext4_fsmap)); |
676 | |
677 | if (!ext4_getfsmap_check_keys(low_key: dkeys, high_key: &head->fmh_keys[1])) |
678 | return -EINVAL; |
679 | |
680 | info.gfi_next_fsblk = head->fmh_keys[0].fmr_physical + |
681 | head->fmh_keys[0].fmr_length; |
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 range the user asked for? */ |
689 | if (!handlers[i].gfd_fn) |
690 | continue; |
691 | if (head->fmh_keys[0].fmr_device > handlers[i].gfd_dev) |
692 | continue; |
693 | if (head->fmh_keys[1].fmr_device < handlers[i].gfd_dev) |
694 | break; |
695 | |
696 | /* |
697 | * If this device number matches the high key, we have |
698 | * to pass the high key to the handler to limit the |
699 | * query results. If the device number exceeds the |
700 | * low key, zero out the low key so that we get |
701 | * everything from the beginning. |
702 | */ |
703 | if (handlers[i].gfd_dev == head->fmh_keys[1].fmr_device) |
704 | dkeys[1] = head->fmh_keys[1]; |
705 | if (handlers[i].gfd_dev > head->fmh_keys[0].fmr_device) |
706 | memset(&dkeys[0], 0, sizeof(struct ext4_fsmap)); |
707 | |
708 | info.gfi_dev = handlers[i].gfd_dev; |
709 | info.gfi_last = false; |
710 | info.gfi_agno = -1; |
711 | error = handlers[i].gfd_fn(sb, dkeys, &info); |
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 | |