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f5166768 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
0c9ec4be DW |
2 | /* |
3 | * Copyright (C) 2017 Oracle. All Rights Reserved. | |
4 | * | |
5 | * Author: Darrick J. Wong <darrick.wong@oracle.com> | |
0c9ec4be DW |
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) { | |
af8c53c8 DW |
111 | if (info->gfi_head->fmh_entries == UINT_MAX) |
112 | return EXT4_QUERY_RANGE_ABORT; | |
113 | ||
0c9ec4be DW |
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, info->gfi_next_fsblk, | |
138 | &agno, &cno); | |
139 | trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno, | |
140 | EXT4_C2B(sbi, cno), | |
141 | 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, rec_fsblk, &agno, &cno); | |
163 | trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno, EXT4_C2B(sbi, cno), | |
164 | rec->fmr_length, 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, 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(&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, &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(&p->fmr_list); | |
227 | kfree(p); | |
228 | } else if (p->fmr_physical < fsb) { | |
229 | error = ext4_getfsmap_helper(sb, info, p); | |
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 of a bg, buffer it. */ | |
245 | if (ext4_fsmap_next_pblk(&irec) == | |
246 | ext4_group_first_block_no(sb, agno + 1)) { | |
247 | info->gfi_lastfree = irec; | |
248 | return 0; | |
249 | } | |
250 | ||
251 | /* Otherwise, emit it */ | |
252 | return ext4_getfsmap_helper(sb, info, &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, info->gfi_dev, 0, | |
269 | info->gfi_low.fmr_physical, | |
270 | info->gfi_low.fmr_length, | |
271 | info->gfi_low.fmr_owner); | |
272 | ||
273 | 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 | 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_maxlen; | |
284 | irec.fmr_owner = EXT4_FMR_OWN_LOG; | |
285 | irec.fmr_flags = 0; | |
286 | ||
287 | return ext4_getfsmap_helper(sb, info, &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(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_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, 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, agno)) { | |
327 | error = ext4_getfsmap_fill(meta_list, fsb, 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, 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 | struct list_head *a, | |
358 | 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(&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(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(&p->fmr_list); | |
403 | kfree(p); | |
404 | } | |
405 | } | |
406 | ||
407 | /* Find all the fixed metadata in the filesystem. */ | |
472d8ea1 MM |
408 | static int ext4_getfsmap_find_fixed_metadata(struct super_block *sb, |
409 | struct list_head *meta_list) | |
0c9ec4be DW |
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_groups_count; agno++) { | |
419 | gdp = ext4_get_group_desc(sb, 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 | ext4_block_bitmap(sb, gdp), 1, | |
433 | EXT4_FMR_OWN_BLKBM); | |
434 | if (error) | |
435 | goto err; | |
436 | ||
437 | /* Inode bitmap */ | |
438 | error = ext4_getfsmap_fill(meta_list, | |
439 | ext4_inode_bitmap(sb, gdp), 1, | |
440 | EXT4_FMR_OWN_INOBM); | |
441 | if (error) | |
442 | goto err; | |
443 | ||
444 | /* Inodes */ | |
445 | error = ext4_getfsmap_fill(meta_list, | |
446 | ext4_inode_table(sb, gdp), | |
447 | 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, meta_list, 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; | |
4a495624 | 473 | ext4_fsblk_t bofs; |
0c9ec4be DW |
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 | ||
4a495624 | 481 | bofs = le32_to_cpu(sbi->s_es->s_first_data_block); |
0c9ec4be DW |
482 | eofs = ext4_blocks_count(sbi->s_es); |
483 | if (keys[0].fmr_physical >= eofs) | |
484 | return 0; | |
4a495624 DW |
485 | else if (keys[0].fmr_physical < bofs) |
486 | keys[0].fmr_physical = bofs; | |
0c9ec4be DW |
487 | if (keys[1].fmr_physical >= eofs) |
488 | keys[1].fmr_physical = eofs - 1; | |
489 | start_fsb = keys[0].fmr_physical; | |
490 | end_fsb = keys[1].fmr_physical; | |
491 | ||
492 | /* Determine first and last group to examine based on start and end */ | |
493 | ext4_get_group_no_and_offset(sb, start_fsb, &start_ag, &first_cluster); | |
494 | 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 | info->gfi_low = keys[0]; | |
502 | info->gfi_low.fmr_physical = EXT4_C2B(sbi, first_cluster); | |
503 | info->gfi_low.fmr_length = 0; | |
504 | ||
505 | memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high)); | |
506 | ||
507 | /* Assemble a list of all the fixed-location metadata. */ | |
508 | error = ext4_getfsmap_find_fixed_metadata(sb, &info->gfi_meta_list); | |
509 | if (error) | |
510 | goto err; | |
511 | ||
512 | /* Query each bg */ | |
513 | for (info->gfi_agno = start_ag; | |
514 | info->gfi_agno <= end_ag; | |
515 | 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 | if (info->gfi_agno == end_ag) { | |
521 | info->gfi_high = keys[1]; | |
522 | info->gfi_high.fmr_physical = EXT4_C2B(sbi, | |
523 | last_cluster); | |
524 | info->gfi_high.fmr_length = 0; | |
525 | } | |
526 | ||
527 | 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 | 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 | error = ext4_mballoc_query_range(sb, info->gfi_agno, | |
538 | EXT4_B2C(sbi, info->gfi_low.fmr_physical), | |
539 | EXT4_B2C(sbi, info->gfi_high.fmr_physical), | |
540 | ext4_getfsmap_datadev_helper, info); | |
541 | if (error) | |
542 | 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 | if (info->gfi_agno == start_ag) | |
549 | memset(&info->gfi_low, 0, sizeof(info->gfi_low)); | |
550 | } | |
551 | ||
552 | /* Do we have a retained free extent? */ | |
553 | if (info->gfi_lastfree.fmr_owner) { | |
554 | error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree); | |
555 | if (error) | |
556 | goto err; | |
557 | } | |
558 | ||
559 | /* Report any gaps at the end of the bg */ | |
560 | info->gfi_last = true; | |
561 | error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster, 0, info); | |
562 | if (error) | |
563 | goto err; | |
564 | ||
565 | err: | |
566 | ext4_getfsmap_free_fixed_metadata(&info->gfi_meta_list); | |
567 | return error; | |
568 | } | |
569 | ||
570 | /* Do we recognize the device? */ | |
571 | static bool ext4_getfsmap_is_valid_device(struct super_block *sb, | |
572 | struct ext4_fsmap *fm) | |
573 | { | |
574 | if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX || | |
575 | fm->fmr_device == new_encode_dev(sb->s_bdev->bd_dev)) | |
576 | return true; | |
ee7ed3aa CX |
577 | if (EXT4_SB(sb)->s_journal_bdev && |
578 | fm->fmr_device == new_encode_dev(EXT4_SB(sb)->s_journal_bdev->bd_dev)) | |
0c9ec4be DW |
579 | return true; |
580 | return false; | |
581 | } | |
582 | ||
583 | /* Ensure that the low key is less than the high key. */ | |
584 | static bool ext4_getfsmap_check_keys(struct ext4_fsmap *low_key, | |
585 | struct ext4_fsmap *high_key) | |
586 | { | |
587 | if (low_key->fmr_device > high_key->fmr_device) | |
588 | return false; | |
589 | if (low_key->fmr_device < high_key->fmr_device) | |
590 | return true; | |
591 | ||
592 | if (low_key->fmr_physical > high_key->fmr_physical) | |
593 | return false; | |
594 | if (low_key->fmr_physical < high_key->fmr_physical) | |
595 | return true; | |
596 | ||
597 | if (low_key->fmr_owner > high_key->fmr_owner) | |
598 | return false; | |
599 | if (low_key->fmr_owner < high_key->fmr_owner) | |
600 | 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 | int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head, | |
628 | ext4_fsmap_format_t formatter, void *arg) | |
629 | { | |
630 | struct ext4_fsmap dkeys[2]; /* per-dev keys */ | |
631 | struct ext4_getfsmap_dev handlers[EXT4_GETFSMAP_DEVS]; | |
0ba33fac | 632 | struct ext4_getfsmap_info info = { NULL }; |
0c9ec4be DW |
633 | int i; |
634 | int error = 0; | |
635 | ||
636 | if (head->fmh_iflags & ~FMH_IF_VALID) | |
637 | return -EINVAL; | |
638 | if (!ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[0]) || | |
639 | !ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[1])) | |
640 | return -EINVAL; | |
641 | ||
642 | head->fmh_entries = 0; | |
643 | ||
644 | /* Set up our device handlers. */ | |
645 | memset(handlers, 0, sizeof(handlers)); | |
646 | handlers[0].gfd_dev = new_encode_dev(sb->s_bdev->bd_dev); | |
647 | handlers[0].gfd_fn = ext4_getfsmap_datadev; | |
ee7ed3aa | 648 | if (EXT4_SB(sb)->s_journal_bdev) { |
0c9ec4be | 649 | handlers[1].gfd_dev = new_encode_dev( |
ee7ed3aa | 650 | EXT4_SB(sb)->s_journal_bdev->bd_dev); |
0c9ec4be DW |
651 | handlers[1].gfd_fn = ext4_getfsmap_logdev; |
652 | } | |
653 | ||
654 | 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 | dkeys[0] = head->fmh_keys[0]; | |
669 | dkeys[0].fmr_physical += dkeys[0].fmr_length; | |
670 | dkeys[0].fmr_owner = 0; | |
671 | dkeys[0].fmr_length = 0; | |
672 | memset(&dkeys[1], 0xFF, sizeof(struct ext4_fsmap)); | |
673 | ||
674 | if (!ext4_getfsmap_check_keys(dkeys, &head->fmh_keys[1])) | |
675 | return -EINVAL; | |
676 | ||
677 | info.gfi_next_fsblk = head->fmh_keys[0].fmr_physical + | |
678 | head->fmh_keys[0].fmr_length; | |
679 | info.gfi_formatter = formatter; | |
680 | info.gfi_format_arg = arg; | |
681 | info.gfi_head = head; | |
682 | ||
683 | /* For each device we support... */ | |
684 | for (i = 0; i < EXT4_GETFSMAP_DEVS; i++) { | |
685 | /* Is this device within the range the user asked for? */ | |
686 | if (!handlers[i].gfd_fn) | |
687 | continue; | |
688 | if (head->fmh_keys[0].fmr_device > handlers[i].gfd_dev) | |
689 | continue; | |
690 | 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 | if (handlers[i].gfd_dev == head->fmh_keys[1].fmr_device) | |
701 | dkeys[1] = head->fmh_keys[1]; | |
702 | if (handlers[i].gfd_dev > head->fmh_keys[0].fmr_device) | |
703 | memset(&dkeys[0], 0, sizeof(struct ext4_fsmap)); | |
704 | ||
705 | info.gfi_dev = handlers[i].gfd_dev; | |
706 | info.gfi_last = false; | |
707 | info.gfi_agno = -1; | |
708 | error = handlers[i].gfd_fn(sb, dkeys, &info); | |
709 | if (error) | |
710 | break; | |
711 | info.gfi_next_fsblk = 0; | |
712 | } | |
713 | ||
714 | head->fmh_oflags = FMH_OF_DEV_T; | |
715 | return error; | |
716 | } |