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1 | /* |
2 | * Copyright (C) 2017 Oracle. All Rights Reserved. | |
3 | * | |
4 | * Author: Darrick J. Wong <darrick.wong@oracle.com> | |
5 | * | |
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. | |
10 | * | |
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. | |
15 | * | |
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. | |
19 | */ | |
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> | |
27 | ||
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) | |
31 | { | |
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; | |
41 | } | |
42 | ||
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) | |
46 | { | |
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; | |
52 | } | |
53 | ||
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? */ | |
67 | }; | |
68 | ||
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; | |
75 | }; | |
76 | ||
77 | /* Compare two getfsmap device handlers. */ | |
78 | static int ext4_getfsmap_dev_compare(const void *p1, const void *p2) | |
79 | { | |
80 | const struct ext4_getfsmap_dev *d1 = p1; | |
81 | const struct ext4_getfsmap_dev *d2 = p2; | |
82 | ||
83 | return d1->gfd_dev - d2->gfd_dev; | |
84 | } | |
85 | ||
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) | |
89 | { | |
90 | return rec->fmr_physical < info->gfi_low.fmr_physical; | |
91 | } | |
92 | ||
93 | /* | |
94 | * Format a reverse mapping for getfsmap, having translated rm_startblock | |
95 | * into the appropriate daddr units. | |
96 | */ | |
97 | static int ext4_getfsmap_helper(struct super_block *sb, | |
98 | struct ext4_getfsmap_info *info, | |
99 | struct ext4_fsmap *rec) | |
100 | { | |
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; | |
107 | ||
108 | if (fatal_signal_pending(current)) | |
109 | return -EINTR; | |
110 | ||
111 | /* | |
112 | * Filter out records that start before our startpoint, if the | |
113 | * caller requested that. | |
114 | */ | |
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; | |
120 | } | |
121 | ||
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++; | |
126 | ||
127 | if (info->gfi_last) | |
128 | return EXT4_QUERY_RANGE_CONTINUE; | |
129 | ||
130 | info->gfi_head->fmh_entries++; | |
131 | ||
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; | |
136 | } | |
137 | ||
138 | /* | |
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. | |
142 | */ | |
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; | |
146 | ||
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); | |
153 | ||
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++; | |
163 | } | |
164 | ||
165 | if (info->gfi_last) | |
166 | goto out; | |
167 | ||
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; | |
171 | ||
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); | |
175 | ||
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++; | |
185 | ||
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; | |
191 | } | |
192 | ||
193 | static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr) | |
194 | { | |
195 | return fmr->fmr_physical + fmr->fmr_length; | |
196 | } | |
197 | ||
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) | |
202 | { | |
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; | |
211 | ||
212 | fsb = (EXT4_C2B(sbi, start) + ext4_group_first_block_no(sb, agno)); | |
213 | fslen = EXT4_C2B(sbi, len); | |
214 | ||
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; | |
221 | } | |
222 | ||
223 | /* | |
224 | * There's a gap between the two free extents; emit the | |
225 | * retained extent prior to merging the meta_list. | |
226 | */ | |
227 | error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree); | |
228 | if (error) | |
229 | return error; | |
230 | info->gfi_lastfree.fmr_owner = 0; | |
231 | } | |
232 | ||
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; | |
242 | ||
243 | list_del(&p->fmr_list); | |
244 | kfree(p); | |
245 | } | |
246 | } | |
247 | ||
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; | |
253 | ||
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; | |
259 | } | |
260 | ||
261 | /* Otherwise, emit it */ | |
262 | return ext4_getfsmap_helper(sb, info, &irec); | |
263 | } | |
264 | ||
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) | |
268 | { | |
269 | journal_t *journal = EXT4_SB(sb)->s_journal; | |
270 | struct ext4_fsmap irec; | |
271 | ||
272 | /* Set up search keys */ | |
273 | info->gfi_low = keys[0]; | |
274 | info->gfi_low.fmr_length = 0; | |
275 | ||
276 | memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high)); | |
277 | ||
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); | |
282 | ||
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); | |
287 | ||
288 | if (keys[0].fmr_physical > 0) | |
289 | return 0; | |
290 | ||
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; | |
296 | ||
297 | return ext4_getfsmap_helper(sb, info, &irec); | |
298 | } | |
299 | ||
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) | |
304 | { | |
305 | struct ext4_fsmap *fsm; | |
306 | ||
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); | |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
320 | /* | |
321 | * This function returns the number of file system metadata blocks at | |
322 | * the beginning of a block group, including the reserved gdt blocks. | |
323 | */ | |
324 | static unsigned int ext4_getfsmap_find_sb(struct super_block *sb, | |
325 | ext4_group_t agno, | |
326 | struct list_head *meta_list) | |
327 | { | |
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; | |
334 | ||
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++; | |
341 | } | |
342 | ||
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; | |
352 | ||
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; | |
360 | } | |
361 | ||
362 | return 0; | |
363 | } | |
364 | ||
365 | /* Compare two fsmap items. */ | |
366 | static int ext4_getfsmap_compare(void *priv, | |
367 | struct list_head *a, | |
368 | struct list_head *b) | |
369 | { | |
370 | struct ext4_fsmap *fa; | |
371 | struct ext4_fsmap *fb; | |
372 | ||
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; | |
380 | } | |
381 | ||
382 | /* Merge adjacent extents of fixed metadata. */ | |
383 | static void ext4_getfsmap_merge_fixed_metadata(struct list_head *meta_list) | |
384 | { | |
385 | struct ext4_fsmap *p; | |
386 | struct ext4_fsmap *prev = NULL; | |
387 | struct ext4_fsmap *tmp; | |
388 | ||
389 | list_for_each_entry_safe(p, tmp, meta_list, fmr_list) { | |
390 | if (!prev) { | |
391 | prev = p; | |
392 | continue; | |
393 | } | |
394 | ||
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; | |
402 | } | |
403 | } | |
404 | ||
405 | /* Free a list of fixed metadata. */ | |
406 | static void ext4_getfsmap_free_fixed_metadata(struct list_head *meta_list) | |
407 | { | |
408 | struct ext4_fsmap *p; | |
409 | struct ext4_fsmap *tmp; | |
410 | ||
411 | list_for_each_entry_safe(p, tmp, meta_list, fmr_list) { | |
412 | list_del(&p->fmr_list); | |
413 | kfree(p); | |
414 | } | |
415 | } | |
416 | ||
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) | |
420 | { | |
421 | struct ext4_group_desc *gdp; | |
422 | ext4_group_t agno; | |
423 | int error; | |
424 | ||
425 | INIT_LIST_HEAD(meta_list); | |
426 | ||
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; | |
433 | } | |
434 | ||
435 | /* Superblock & GDT */ | |
436 | error = ext4_getfsmap_find_sb(sb, agno, meta_list); | |
437 | if (error) | |
438 | goto err; | |
439 | ||
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; | |
446 | ||
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; | |
453 | ||
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; | |
461 | } | |
462 | ||
463 | /* Sort the list */ | |
464 | list_sort(NULL, meta_list, ext4_getfsmap_compare); | |
465 | ||
466 | /* Merge adjacent extents */ | |
467 | ext4_getfsmap_merge_fixed_metadata(meta_list); | |
468 | ||
469 | return 0; | |
470 | err: | |
471 | ext4_getfsmap_free_fixed_metadata(meta_list); | |
472 | return error; | |
473 | } | |
474 | ||
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) | |
479 | { | |
480 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
481 | ext4_fsblk_t start_fsb; | |
482 | ext4_fsblk_t end_fsb; | |
4a495624 | 483 | ext4_fsblk_t bofs; |
0c9ec4be DW |
484 | ext4_fsblk_t eofs; |
485 | ext4_group_t start_ag; | |
486 | ext4_group_t end_ag; | |
487 | ext4_grpblk_t first_cluster; | |
488 | ext4_grpblk_t last_cluster; | |
489 | int error = 0; | |
490 | ||
4a495624 | 491 | bofs = le32_to_cpu(sbi->s_es->s_first_data_block); |
0c9ec4be DW |
492 | eofs = ext4_blocks_count(sbi->s_es); |
493 | if (keys[0].fmr_physical >= eofs) | |
494 | return 0; | |
4a495624 DW |
495 | else if (keys[0].fmr_physical < bofs) |
496 | keys[0].fmr_physical = bofs; | |
0c9ec4be DW |
497 | if (keys[1].fmr_physical >= eofs) |
498 | keys[1].fmr_physical = eofs - 1; | |
499 | start_fsb = keys[0].fmr_physical; | |
500 | end_fsb = keys[1].fmr_physical; | |
501 | ||
502 | /* Determine first and last group to examine based on start and end */ | |
503 | ext4_get_group_no_and_offset(sb, start_fsb, &start_ag, &first_cluster); | |
504 | ext4_get_group_no_and_offset(sb, end_fsb, &end_ag, &last_cluster); | |
505 | ||
506 | /* | |
507 | * Convert the fsmap low/high keys to bg based keys. Initialize | |
508 | * low to the fsmap low key and max out the high key to the end | |
509 | * of the bg. | |
510 | */ | |
511 | info->gfi_low = keys[0]; | |
512 | info->gfi_low.fmr_physical = EXT4_C2B(sbi, first_cluster); | |
513 | info->gfi_low.fmr_length = 0; | |
514 | ||
515 | memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high)); | |
516 | ||
517 | /* Assemble a list of all the fixed-location metadata. */ | |
518 | error = ext4_getfsmap_find_fixed_metadata(sb, &info->gfi_meta_list); | |
519 | if (error) | |
520 | goto err; | |
521 | ||
522 | /* Query each bg */ | |
523 | for (info->gfi_agno = start_ag; | |
524 | info->gfi_agno <= end_ag; | |
525 | info->gfi_agno++) { | |
526 | /* | |
527 | * Set the bg high key from the fsmap high key if this | |
528 | * is the last bg that we're querying. | |
529 | */ | |
530 | if (info->gfi_agno == end_ag) { | |
531 | info->gfi_high = keys[1]; | |
532 | info->gfi_high.fmr_physical = EXT4_C2B(sbi, | |
533 | last_cluster); | |
534 | info->gfi_high.fmr_length = 0; | |
535 | } | |
536 | ||
537 | trace_ext4_fsmap_low_key(sb, info->gfi_dev, info->gfi_agno, | |
538 | info->gfi_low.fmr_physical, | |
539 | info->gfi_low.fmr_length, | |
540 | info->gfi_low.fmr_owner); | |
541 | ||
542 | trace_ext4_fsmap_high_key(sb, info->gfi_dev, info->gfi_agno, | |
543 | info->gfi_high.fmr_physical, | |
544 | info->gfi_high.fmr_length, | |
545 | info->gfi_high.fmr_owner); | |
546 | ||
547 | error = ext4_mballoc_query_range(sb, info->gfi_agno, | |
548 | EXT4_B2C(sbi, info->gfi_low.fmr_physical), | |
549 | EXT4_B2C(sbi, info->gfi_high.fmr_physical), | |
550 | ext4_getfsmap_datadev_helper, info); | |
551 | if (error) | |
552 | goto err; | |
553 | ||
554 | /* | |
555 | * Set the bg low key to the start of the bg prior to | |
556 | * moving on to the next bg. | |
557 | */ | |
558 | if (info->gfi_agno == start_ag) | |
559 | memset(&info->gfi_low, 0, sizeof(info->gfi_low)); | |
560 | } | |
561 | ||
562 | /* Do we have a retained free extent? */ | |
563 | if (info->gfi_lastfree.fmr_owner) { | |
564 | error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree); | |
565 | if (error) | |
566 | goto err; | |
567 | } | |
568 | ||
569 | /* Report any gaps at the end of the bg */ | |
570 | info->gfi_last = true; | |
571 | error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster, 0, info); | |
572 | if (error) | |
573 | goto err; | |
574 | ||
575 | err: | |
576 | ext4_getfsmap_free_fixed_metadata(&info->gfi_meta_list); | |
577 | return error; | |
578 | } | |
579 | ||
580 | /* Do we recognize the device? */ | |
581 | static bool ext4_getfsmap_is_valid_device(struct super_block *sb, | |
582 | struct ext4_fsmap *fm) | |
583 | { | |
584 | if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX || | |
585 | fm->fmr_device == new_encode_dev(sb->s_bdev->bd_dev)) | |
586 | return true; | |
587 | if (EXT4_SB(sb)->journal_bdev && | |
588 | fm->fmr_device == new_encode_dev(EXT4_SB(sb)->journal_bdev->bd_dev)) | |
589 | return true; | |
590 | return false; | |
591 | } | |
592 | ||
593 | /* Ensure that the low key is less than the high key. */ | |
594 | static bool ext4_getfsmap_check_keys(struct ext4_fsmap *low_key, | |
595 | struct ext4_fsmap *high_key) | |
596 | { | |
597 | if (low_key->fmr_device > high_key->fmr_device) | |
598 | return false; | |
599 | if (low_key->fmr_device < high_key->fmr_device) | |
600 | return true; | |
601 | ||
602 | if (low_key->fmr_physical > high_key->fmr_physical) | |
603 | return false; | |
604 | if (low_key->fmr_physical < high_key->fmr_physical) | |
605 | return true; | |
606 | ||
607 | if (low_key->fmr_owner > high_key->fmr_owner) | |
608 | return false; | |
609 | if (low_key->fmr_owner < high_key->fmr_owner) | |
610 | return true; | |
611 | ||
612 | return false; | |
613 | } | |
614 | ||
615 | #define EXT4_GETFSMAP_DEVS 2 | |
616 | /* | |
617 | * Get filesystem's extents as described in head, and format for | |
618 | * output. Calls formatter to fill the user's buffer until all | |
619 | * extents are mapped, until the passed-in head->fmh_count slots have | |
620 | * been filled, or until the formatter short-circuits the loop, if it | |
621 | * is tracking filled-in extents on its own. | |
622 | * | |
623 | * Key to Confusion | |
624 | * ---------------- | |
625 | * There are multiple levels of keys and counters at work here: | |
626 | * _fsmap_head.fmh_keys -- low and high fsmap keys passed in; | |
627 | * these reflect fs-wide block addrs. | |
628 | * dkeys -- fmh_keys used to query each device; | |
629 | * these are fmh_keys but w/ the low key | |
630 | * bumped up by fmr_length. | |
631 | * _getfsmap_info.gfi_next_fsblk-- next fs block we expect to see; this | |
632 | * is how we detect gaps in the fsmap | |
633 | * records and report them. | |
634 | * _getfsmap_info.gfi_low/high -- per-bg low/high keys computed from | |
635 | * dkeys; used to query the free space. | |
636 | */ | |
637 | int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head, | |
638 | ext4_fsmap_format_t formatter, void *arg) | |
639 | { | |
640 | struct ext4_fsmap dkeys[2]; /* per-dev keys */ | |
641 | struct ext4_getfsmap_dev handlers[EXT4_GETFSMAP_DEVS]; | |
642 | struct ext4_getfsmap_info info = {0}; | |
643 | int i; | |
644 | int error = 0; | |
645 | ||
646 | if (head->fmh_iflags & ~FMH_IF_VALID) | |
647 | return -EINVAL; | |
648 | if (!ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[0]) || | |
649 | !ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[1])) | |
650 | return -EINVAL; | |
651 | ||
652 | head->fmh_entries = 0; | |
653 | ||
654 | /* Set up our device handlers. */ | |
655 | memset(handlers, 0, sizeof(handlers)); | |
656 | handlers[0].gfd_dev = new_encode_dev(sb->s_bdev->bd_dev); | |
657 | handlers[0].gfd_fn = ext4_getfsmap_datadev; | |
658 | if (EXT4_SB(sb)->journal_bdev) { | |
659 | handlers[1].gfd_dev = new_encode_dev( | |
660 | EXT4_SB(sb)->journal_bdev->bd_dev); | |
661 | handlers[1].gfd_fn = ext4_getfsmap_logdev; | |
662 | } | |
663 | ||
664 | sort(handlers, EXT4_GETFSMAP_DEVS, sizeof(struct ext4_getfsmap_dev), | |
665 | ext4_getfsmap_dev_compare, NULL); | |
666 | ||
667 | /* | |
668 | * To continue where we left off, we allow userspace to use the | |
669 | * last mapping from a previous call as the low key of the next. | |
670 | * This is identified by a non-zero length in the low key. We | |
671 | * have to increment the low key in this scenario to ensure we | |
672 | * don't return the same mapping again, and instead return the | |
673 | * very next mapping. | |
674 | * | |
675 | * Bump the physical offset as there can be no other mapping for | |
676 | * the same physical block range. | |
677 | */ | |
678 | dkeys[0] = head->fmh_keys[0]; | |
679 | dkeys[0].fmr_physical += dkeys[0].fmr_length; | |
680 | dkeys[0].fmr_owner = 0; | |
681 | dkeys[0].fmr_length = 0; | |
682 | memset(&dkeys[1], 0xFF, sizeof(struct ext4_fsmap)); | |
683 | ||
684 | if (!ext4_getfsmap_check_keys(dkeys, &head->fmh_keys[1])) | |
685 | return -EINVAL; | |
686 | ||
687 | info.gfi_next_fsblk = head->fmh_keys[0].fmr_physical + | |
688 | head->fmh_keys[0].fmr_length; | |
689 | info.gfi_formatter = formatter; | |
690 | info.gfi_format_arg = arg; | |
691 | info.gfi_head = head; | |
692 | ||
693 | /* For each device we support... */ | |
694 | for (i = 0; i < EXT4_GETFSMAP_DEVS; i++) { | |
695 | /* Is this device within the range the user asked for? */ | |
696 | if (!handlers[i].gfd_fn) | |
697 | continue; | |
698 | if (head->fmh_keys[0].fmr_device > handlers[i].gfd_dev) | |
699 | continue; | |
700 | if (head->fmh_keys[1].fmr_device < handlers[i].gfd_dev) | |
701 | break; | |
702 | ||
703 | /* | |
704 | * If this device number matches the high key, we have | |
705 | * to pass the high key to the handler to limit the | |
706 | * query results. If the device number exceeds the | |
707 | * low key, zero out the low key so that we get | |
708 | * everything from the beginning. | |
709 | */ | |
710 | if (handlers[i].gfd_dev == head->fmh_keys[1].fmr_device) | |
711 | dkeys[1] = head->fmh_keys[1]; | |
712 | if (handlers[i].gfd_dev > head->fmh_keys[0].fmr_device) | |
713 | memset(&dkeys[0], 0, sizeof(struct ext4_fsmap)); | |
714 | ||
715 | info.gfi_dev = handlers[i].gfd_dev; | |
716 | info.gfi_last = false; | |
717 | info.gfi_agno = -1; | |
718 | error = handlers[i].gfd_fn(sb, dkeys, &info); | |
719 | if (error) | |
720 | break; | |
721 | info.gfi_next_fsblk = 0; | |
722 | } | |
723 | ||
724 | head->fmh_oflags = FMH_OF_DEV_T; | |
725 | return error; | |
726 | } |