1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Copyright (c) 2000-2005 Silicon Graphics, Inc. |
4 | * Copyright (c) 2013 Red Hat, Inc. |
5 | * All Rights Reserved. |
6 | */ |
7 | #include "xfs.h" |
8 | #include "xfs_fs.h" |
9 | #include "xfs_shared.h" |
10 | #include "xfs_format.h" |
11 | #include "xfs_log_format.h" |
12 | #include "xfs_trans_resv.h" |
13 | #include "xfs_mount.h" |
14 | #include "xfs_inode.h" |
15 | #include "xfs_dir2.h" |
16 | #include "xfs_dir2_priv.h" |
17 | #include "xfs_trace.h" |
18 | #include "xfs_bmap.h" |
19 | #include "xfs_trans.h" |
20 | #include "xfs_error.h" |
21 | #include "xfs_health.h" |
22 | |
23 | /* |
24 | * Directory file type support functions |
25 | */ |
26 | static unsigned char xfs_dir3_filetype_table[] = { |
27 | DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, |
28 | DT_FIFO, DT_SOCK, DT_LNK, DT_WHT, |
29 | }; |
30 | |
31 | unsigned char |
32 | xfs_dir3_get_dtype( |
33 | struct xfs_mount *mp, |
34 | uint8_t filetype) |
35 | { |
36 | if (!xfs_has_ftype(mp)) |
37 | return DT_UNKNOWN; |
38 | |
39 | if (filetype >= XFS_DIR3_FT_MAX) |
40 | return DT_UNKNOWN; |
41 | |
42 | return xfs_dir3_filetype_table[filetype]; |
43 | } |
44 | |
45 | STATIC int |
46 | xfs_dir2_sf_getdents( |
47 | struct xfs_da_args *args, |
48 | struct dir_context *ctx) |
49 | { |
50 | int i; /* shortform entry number */ |
51 | struct xfs_inode *dp = args->dp; /* incore directory inode */ |
52 | struct xfs_mount *mp = dp->i_mount; |
53 | xfs_dir2_dataptr_t off; /* current entry's offset */ |
54 | xfs_dir2_sf_entry_t *sfep; /* shortform directory entry */ |
55 | struct xfs_dir2_sf_hdr *sfp = dp->i_df.if_data; |
56 | xfs_dir2_dataptr_t dot_offset; |
57 | xfs_dir2_dataptr_t dotdot_offset; |
58 | xfs_ino_t ino; |
59 | struct xfs_da_geometry *geo = args->geo; |
60 | |
61 | ASSERT(dp->i_df.if_format == XFS_DINODE_FMT_LOCAL); |
62 | ASSERT(dp->i_df.if_bytes == dp->i_disk_size); |
63 | ASSERT(sfp != NULL); |
64 | |
65 | /* |
66 | * If the block number in the offset is out of range, we're done. |
67 | */ |
68 | if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk) |
69 | return 0; |
70 | |
71 | /* |
72 | * Precalculate offsets for "." and ".." as we will always need them. |
73 | * This relies on the fact that directories always start with the |
74 | * entries for "." and "..". |
75 | */ |
76 | dot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, |
77 | geo->data_entry_offset); |
78 | dotdot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, |
79 | geo->data_entry_offset + |
80 | xfs_dir2_data_entsize(mp, sizeof("." ) - 1)); |
81 | |
82 | /* |
83 | * Put . entry unless we're starting past it. |
84 | */ |
85 | if (ctx->pos <= dot_offset) { |
86 | ctx->pos = dot_offset & 0x7fffffff; |
87 | if (!dir_emit(ctx, name: "." , namelen: 1, ino: dp->i_ino, DT_DIR)) |
88 | return 0; |
89 | } |
90 | |
91 | /* |
92 | * Put .. entry unless we're starting past it. |
93 | */ |
94 | if (ctx->pos <= dotdot_offset) { |
95 | ino = xfs_dir2_sf_get_parent_ino(sfp); |
96 | ctx->pos = dotdot_offset & 0x7fffffff; |
97 | if (!dir_emit(ctx, name: ".." , namelen: 2, ino, DT_DIR)) |
98 | return 0; |
99 | } |
100 | |
101 | /* |
102 | * Loop while there are more entries and put'ing works. |
103 | */ |
104 | sfep = xfs_dir2_sf_firstentry(sfp); |
105 | for (i = 0; i < sfp->count; i++) { |
106 | uint8_t filetype; |
107 | |
108 | off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, |
109 | xfs_dir2_sf_get_offset(sfep)); |
110 | |
111 | if (ctx->pos > off) { |
112 | sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep); |
113 | continue; |
114 | } |
115 | |
116 | ino = xfs_dir2_sf_get_ino(mp, sfp, sfep); |
117 | filetype = xfs_dir2_sf_get_ftype(mp, sfep); |
118 | ctx->pos = off & 0x7fffffff; |
119 | if (XFS_IS_CORRUPT(dp->i_mount, |
120 | !xfs_dir2_namecheck(sfep->name, |
121 | sfep->namelen))) { |
122 | xfs_dirattr_mark_sick(dp, XFS_DATA_FORK); |
123 | return -EFSCORRUPTED; |
124 | } |
125 | if (!dir_emit(ctx, (char *)sfep->name, sfep->namelen, ino, |
126 | xfs_dir3_get_dtype(mp, filetype))) |
127 | return 0; |
128 | sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep); |
129 | } |
130 | |
131 | ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) & |
132 | 0x7fffffff; |
133 | return 0; |
134 | } |
135 | |
136 | /* |
137 | * Readdir for block directories. |
138 | */ |
139 | STATIC int |
140 | xfs_dir2_block_getdents( |
141 | struct xfs_da_args *args, |
142 | struct dir_context *ctx, |
143 | unsigned int *lock_mode) |
144 | { |
145 | struct xfs_inode *dp = args->dp; /* incore directory inode */ |
146 | struct xfs_buf *bp; /* buffer for block */ |
147 | int error; /* error return value */ |
148 | int wantoff; /* starting block offset */ |
149 | xfs_off_t cook; |
150 | struct xfs_da_geometry *geo = args->geo; |
151 | unsigned int offset, next_offset; |
152 | unsigned int end; |
153 | |
154 | /* |
155 | * If the block number in the offset is out of range, we're done. |
156 | */ |
157 | if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk) |
158 | return 0; |
159 | |
160 | error = xfs_dir3_block_read(args->trans, dp, &bp); |
161 | if (error) |
162 | return error; |
163 | |
164 | xfs_iunlock(dp, *lock_mode); |
165 | *lock_mode = 0; |
166 | |
167 | /* |
168 | * Extract the byte offset we start at from the seek pointer. |
169 | * We'll skip entries before this. |
170 | */ |
171 | wantoff = xfs_dir2_dataptr_to_off(geo, ctx->pos); |
172 | xfs_dir3_data_check(dp, bp); |
173 | |
174 | /* |
175 | * Loop over the data portion of the block. |
176 | * Each object is a real entry (dep) or an unused one (dup). |
177 | */ |
178 | end = xfs_dir3_data_end_offset(geo, bp->b_addr); |
179 | for (offset = geo->data_entry_offset; |
180 | offset < end; |
181 | offset = next_offset) { |
182 | struct xfs_dir2_data_unused *dup = bp->b_addr + offset; |
183 | struct xfs_dir2_data_entry *dep = bp->b_addr + offset; |
184 | uint8_t filetype; |
185 | |
186 | /* |
187 | * Unused, skip it. |
188 | */ |
189 | if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) { |
190 | next_offset = offset + be16_to_cpu(dup->length); |
191 | continue; |
192 | } |
193 | |
194 | /* |
195 | * Bump pointer for the next iteration. |
196 | */ |
197 | next_offset = offset + |
198 | xfs_dir2_data_entsize(dp->i_mount, dep->namelen); |
199 | |
200 | /* |
201 | * The entry is before the desired starting point, skip it. |
202 | */ |
203 | if (offset < wantoff) |
204 | continue; |
205 | |
206 | cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, offset); |
207 | |
208 | ctx->pos = cook & 0x7fffffff; |
209 | filetype = xfs_dir2_data_get_ftype(dp->i_mount, dep); |
210 | /* |
211 | * If it didn't fit, set the final offset to here & return. |
212 | */ |
213 | if (XFS_IS_CORRUPT(dp->i_mount, |
214 | !xfs_dir2_namecheck(dep->name, |
215 | dep->namelen))) { |
216 | xfs_dirattr_mark_sick(dp, XFS_DATA_FORK); |
217 | error = -EFSCORRUPTED; |
218 | goto out_rele; |
219 | } |
220 | if (!dir_emit(ctx, name: (char *)dep->name, namelen: dep->namelen, |
221 | be64_to_cpu(dep->inumber), |
222 | type: xfs_dir3_get_dtype(mp: dp->i_mount, filetype))) |
223 | goto out_rele; |
224 | } |
225 | |
226 | /* |
227 | * Reached the end of the block. |
228 | * Set the offset to a non-existent block 1 and return. |
229 | */ |
230 | ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) & |
231 | 0x7fffffff; |
232 | out_rele: |
233 | xfs_trans_brelse(args->trans, bp); |
234 | return error; |
235 | } |
236 | |
237 | /* |
238 | * Read a directory block and initiate readahead for blocks beyond that. |
239 | * We maintain a sliding readahead window of the remaining space in the |
240 | * buffer rounded up to the nearest block. |
241 | */ |
242 | STATIC int |
243 | xfs_dir2_leaf_readbuf( |
244 | struct xfs_da_args *args, |
245 | size_t bufsize, |
246 | xfs_dir2_off_t *cur_off, |
247 | xfs_dablk_t *ra_blk, |
248 | struct xfs_buf **bpp) |
249 | { |
250 | struct xfs_inode *dp = args->dp; |
251 | struct xfs_buf *bp = NULL; |
252 | struct xfs_da_geometry *geo = args->geo; |
253 | struct xfs_ifork *ifp = xfs_ifork_ptr(dp, XFS_DATA_FORK); |
254 | struct xfs_bmbt_irec map; |
255 | struct blk_plug plug; |
256 | xfs_dir2_off_t new_off; |
257 | xfs_dablk_t next_ra; |
258 | xfs_dablk_t map_off; |
259 | xfs_dablk_t last_da; |
260 | struct xfs_iext_cursor icur; |
261 | int ra_want; |
262 | int error = 0; |
263 | |
264 | error = xfs_iread_extents(args->trans, dp, XFS_DATA_FORK); |
265 | if (error) |
266 | goto out; |
267 | |
268 | /* |
269 | * Look for mapped directory blocks at or above the current offset. |
270 | * Truncate down to the nearest directory block to start the scanning |
271 | * operation. |
272 | */ |
273 | last_da = xfs_dir2_byte_to_da(geo, XFS_DIR2_LEAF_OFFSET); |
274 | map_off = xfs_dir2_db_to_da(geo, xfs_dir2_byte_to_db(geo, *cur_off)); |
275 | if (!xfs_iext_lookup_extent(dp, ifp, map_off, &icur, &map)) |
276 | goto out; |
277 | if (map.br_startoff >= last_da) |
278 | goto out; |
279 | xfs_trim_extent(&map, map_off, last_da - map_off); |
280 | |
281 | /* Read the directory block of that first mapping. */ |
282 | new_off = xfs_dir2_da_to_byte(geo, map.br_startoff); |
283 | if (new_off > *cur_off) |
284 | *cur_off = new_off; |
285 | error = xfs_dir3_data_read(args->trans, dp, map.br_startoff, 0, &bp); |
286 | if (error) |
287 | goto out; |
288 | |
289 | /* |
290 | * Start readahead for the next bufsize's worth of dir data blocks. |
291 | * We may have already issued readahead for some of that range; |
292 | * ra_blk tracks the last block we tried to read(ahead). |
293 | */ |
294 | ra_want = howmany(bufsize + geo->blksize, (1 << geo->fsblog)); |
295 | if (*ra_blk >= last_da) |
296 | goto out; |
297 | else if (*ra_blk == 0) |
298 | *ra_blk = map.br_startoff; |
299 | next_ra = map.br_startoff + geo->fsbcount; |
300 | if (next_ra >= last_da) |
301 | goto out_no_ra; |
302 | if (map.br_blockcount < geo->fsbcount && |
303 | !xfs_iext_next_extent(ifp, &icur, &map)) |
304 | goto out_no_ra; |
305 | if (map.br_startoff >= last_da) |
306 | goto out_no_ra; |
307 | xfs_trim_extent(&map, next_ra, last_da - next_ra); |
308 | |
309 | /* Start ra for each dir (not fs) block that has a mapping. */ |
310 | blk_start_plug(&plug); |
311 | while (ra_want > 0) { |
312 | next_ra = roundup((xfs_dablk_t)map.br_startoff, geo->fsbcount); |
313 | while (ra_want > 0 && |
314 | next_ra < map.br_startoff + map.br_blockcount) { |
315 | if (next_ra >= last_da) { |
316 | *ra_blk = last_da; |
317 | break; |
318 | } |
319 | if (next_ra > *ra_blk) { |
320 | xfs_dir3_data_readahead(dp, next_ra, |
321 | XFS_DABUF_MAP_HOLE_OK); |
322 | *ra_blk = next_ra; |
323 | } |
324 | ra_want -= geo->fsbcount; |
325 | next_ra += geo->fsbcount; |
326 | } |
327 | if (!xfs_iext_next_extent(ifp, &icur, &map)) { |
328 | *ra_blk = last_da; |
329 | break; |
330 | } |
331 | } |
332 | blk_finish_plug(&plug); |
333 | |
334 | out: |
335 | *bpp = bp; |
336 | return error; |
337 | out_no_ra: |
338 | *ra_blk = last_da; |
339 | goto out; |
340 | } |
341 | |
342 | /* |
343 | * Getdents (readdir) for leaf and node directories. |
344 | * This reads the data blocks only, so is the same for both forms. |
345 | */ |
346 | STATIC int |
347 | xfs_dir2_leaf_getdents( |
348 | struct xfs_da_args *args, |
349 | struct dir_context *ctx, |
350 | size_t bufsize, |
351 | unsigned int *lock_mode) |
352 | { |
353 | struct xfs_inode *dp = args->dp; |
354 | struct xfs_mount *mp = dp->i_mount; |
355 | struct xfs_buf *bp = NULL; /* data block buffer */ |
356 | xfs_dir2_data_entry_t *dep; /* data entry */ |
357 | xfs_dir2_data_unused_t *dup; /* unused entry */ |
358 | struct xfs_da_geometry *geo = args->geo; |
359 | xfs_dablk_t rablk = 0; /* current readahead block */ |
360 | xfs_dir2_off_t curoff; /* current overall offset */ |
361 | int length; /* temporary length value */ |
362 | int byteoff; /* offset in current block */ |
363 | unsigned int offset = 0; |
364 | int error = 0; /* error return value */ |
365 | |
366 | /* |
367 | * If the offset is at or past the largest allowed value, |
368 | * give up right away. |
369 | */ |
370 | if (ctx->pos >= XFS_DIR2_MAX_DATAPTR) |
371 | return 0; |
372 | |
373 | /* |
374 | * Inside the loop we keep the main offset value as a byte offset |
375 | * in the directory file. |
376 | */ |
377 | curoff = xfs_dir2_dataptr_to_byte(ctx->pos); |
378 | |
379 | /* |
380 | * Loop over directory entries until we reach the end offset. |
381 | * Get more blocks and readahead as necessary. |
382 | */ |
383 | while (curoff < XFS_DIR2_LEAF_OFFSET) { |
384 | uint8_t filetype; |
385 | |
386 | /* |
387 | * If we have no buffer, or we're off the end of the |
388 | * current buffer, need to get another one. |
389 | */ |
390 | if (!bp || offset >= geo->blksize) { |
391 | if (bp) { |
392 | xfs_trans_brelse(args->trans, bp); |
393 | bp = NULL; |
394 | } |
395 | |
396 | if (*lock_mode == 0) |
397 | *lock_mode = xfs_ilock_data_map_shared(dp); |
398 | error = xfs_dir2_leaf_readbuf(args, bufsize, &curoff, |
399 | &rablk, &bp); |
400 | if (error || !bp) |
401 | break; |
402 | |
403 | xfs_iunlock(dp, *lock_mode); |
404 | *lock_mode = 0; |
405 | |
406 | xfs_dir3_data_check(dp, bp); |
407 | /* |
408 | * Find our position in the block. |
409 | */ |
410 | offset = geo->data_entry_offset; |
411 | byteoff = xfs_dir2_byte_to_off(geo, curoff); |
412 | /* |
413 | * Skip past the header. |
414 | */ |
415 | if (byteoff == 0) |
416 | curoff += geo->data_entry_offset; |
417 | /* |
418 | * Skip past entries until we reach our offset. |
419 | */ |
420 | else { |
421 | while (offset < byteoff) { |
422 | dup = bp->b_addr + offset; |
423 | |
424 | if (be16_to_cpu(dup->freetag) |
425 | == XFS_DIR2_DATA_FREE_TAG) { |
426 | |
427 | length = be16_to_cpu(dup->length); |
428 | offset += length; |
429 | continue; |
430 | } |
431 | dep = bp->b_addr + offset; |
432 | length = xfs_dir2_data_entsize(mp, |
433 | dep->namelen); |
434 | offset += length; |
435 | } |
436 | /* |
437 | * Now set our real offset. |
438 | */ |
439 | curoff = |
440 | xfs_dir2_db_off_to_byte(geo, |
441 | xfs_dir2_byte_to_db(geo, curoff), |
442 | offset); |
443 | if (offset >= geo->blksize) |
444 | continue; |
445 | } |
446 | } |
447 | |
448 | /* |
449 | * We have a pointer to an entry. Is it a live one? |
450 | */ |
451 | dup = bp->b_addr + offset; |
452 | |
453 | /* |
454 | * No, it's unused, skip over it. |
455 | */ |
456 | if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) { |
457 | length = be16_to_cpu(dup->length); |
458 | offset += length; |
459 | curoff += length; |
460 | continue; |
461 | } |
462 | |
463 | dep = bp->b_addr + offset; |
464 | length = xfs_dir2_data_entsize(mp, dep->namelen); |
465 | filetype = xfs_dir2_data_get_ftype(mp, dep); |
466 | |
467 | ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff; |
468 | if (XFS_IS_CORRUPT(dp->i_mount, |
469 | !xfs_dir2_namecheck(dep->name, |
470 | dep->namelen))) { |
471 | xfs_dirattr_mark_sick(dp, XFS_DATA_FORK); |
472 | error = -EFSCORRUPTED; |
473 | break; |
474 | } |
475 | if (!dir_emit(ctx, (char *)dep->name, dep->namelen, |
476 | be64_to_cpu(dep->inumber), |
477 | xfs_dir3_get_dtype(dp->i_mount, filetype))) |
478 | break; |
479 | |
480 | /* |
481 | * Advance to next entry in the block. |
482 | */ |
483 | offset += length; |
484 | curoff += length; |
485 | /* bufsize may have just been a guess; don't go negative */ |
486 | bufsize = bufsize > length ? bufsize - length : 0; |
487 | } |
488 | |
489 | /* |
490 | * All done. Set output offset value to current offset. |
491 | */ |
492 | if (curoff > xfs_dir2_dataptr_to_byte(XFS_DIR2_MAX_DATAPTR)) |
493 | ctx->pos = XFS_DIR2_MAX_DATAPTR & 0x7fffffff; |
494 | else |
495 | ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff; |
496 | if (bp) |
497 | xfs_trans_brelse(args->trans, bp); |
498 | return error; |
499 | } |
500 | |
501 | /* |
502 | * Read a directory. |
503 | * |
504 | * If supplied, the transaction collects locked dir buffers to avoid |
505 | * nested buffer deadlocks. This function does not dirty the |
506 | * transaction. The caller must hold the IOLOCK (shared or exclusive) |
507 | * before calling this function. |
508 | */ |
509 | int |
510 | xfs_readdir( |
511 | struct xfs_trans *tp, |
512 | struct xfs_inode *dp, |
513 | struct dir_context *ctx, |
514 | size_t bufsize) |
515 | { |
516 | struct xfs_da_args args = { NULL }; |
517 | unsigned int lock_mode; |
518 | bool isblock; |
519 | int error; |
520 | |
521 | trace_xfs_readdir(ip: dp); |
522 | |
523 | if (xfs_is_shutdown(mp: dp->i_mount)) |
524 | return -EIO; |
525 | if (xfs_ifork_zapped(dp, XFS_DATA_FORK)) |
526 | return -EIO; |
527 | |
528 | ASSERT(S_ISDIR(VFS_I(dp)->i_mode)); |
529 | xfs_assert_ilocked(dp, XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL); |
530 | XFS_STATS_INC(dp->i_mount, xs_dir_getdents); |
531 | |
532 | args.dp = dp; |
533 | args.geo = dp->i_mount->m_dir_geo; |
534 | args.trans = tp; |
535 | |
536 | if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL) |
537 | return xfs_dir2_sf_getdents(args: &args, ctx); |
538 | |
539 | lock_mode = xfs_ilock_data_map_shared(dp); |
540 | error = xfs_dir2_isblock(&args, &isblock); |
541 | if (error) |
542 | goto out_unlock; |
543 | |
544 | if (isblock) { |
545 | error = xfs_dir2_block_getdents(args: &args, ctx, lock_mode: &lock_mode); |
546 | goto out_unlock; |
547 | } |
548 | |
549 | error = xfs_dir2_leaf_getdents(args: &args, ctx, bufsize, lock_mode: &lock_mode); |
550 | |
551 | out_unlock: |
552 | if (lock_mode) |
553 | xfs_iunlock(dp, lock_mode); |
554 | return error; |
555 | } |
556 | |