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1/*
2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3 * Copyright (c) 2013 Red Hat, Inc.
4 * All Rights Reserved.
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 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it would be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19#include "xfs.h"
20#include "xfs_fs.h"
21#include "xfs_format.h"
22#include "xfs_log_format.h"
23#include "xfs_trans_resv.h"
24#include "xfs_bit.h"
25#include "xfs_mount.h"
26#include "xfs_da_format.h"
27#include "xfs_da_btree.h"
28#include "xfs_inode.h"
29#include "xfs_dir2.h"
30#include "xfs_dir2_priv.h"
31#include "xfs_error.h"
32#include "xfs_trace.h"
33#include "xfs_bmap.h"
34#include "xfs_trans.h"
35
36/*
37 * Directory file type support functions
38 */
39static unsigned char xfs_dir3_filetype_table[] = {
40 DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK,
41 DT_FIFO, DT_SOCK, DT_LNK, DT_WHT,
42};
43
44static unsigned char
45xfs_dir3_get_dtype(
46 struct xfs_mount *mp,
47 __uint8_t filetype)
48{
49 if (!xfs_sb_version_hasftype(&mp->m_sb))
50 return DT_UNKNOWN;
51
52 if (filetype >= XFS_DIR3_FT_MAX)
53 return DT_UNKNOWN;
54
55 return xfs_dir3_filetype_table[filetype];
56}
57
58STATIC int
59xfs_dir2_sf_getdents(
60 struct xfs_da_args *args,
61 struct dir_context *ctx)
62{
63 int i; /* shortform entry number */
64 struct xfs_inode *dp = args->dp; /* incore directory inode */
65 xfs_dir2_dataptr_t off; /* current entry's offset */
66 xfs_dir2_sf_entry_t *sfep; /* shortform directory entry */
67 xfs_dir2_sf_hdr_t *sfp; /* shortform structure */
68 xfs_dir2_dataptr_t dot_offset;
69 xfs_dir2_dataptr_t dotdot_offset;
70 xfs_ino_t ino;
71 struct xfs_da_geometry *geo = args->geo;
72
73 ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
74 /*
75 * Give up if the directory is way too short.
76 */
77 if (dp->i_d.di_size < offsetof(xfs_dir2_sf_hdr_t, parent)) {
78 ASSERT(XFS_FORCED_SHUTDOWN(dp->i_mount));
79 return -EIO;
80 }
81
82 ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
83 ASSERT(dp->i_df.if_u1.if_data != NULL);
84
85 sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
86
87 ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(sfp->i8count));
88
89 /*
90 * If the block number in the offset is out of range, we're done.
91 */
92 if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
93 return 0;
94
95 /*
96 * Precalculate offsets for . and .. as we will always need them.
97 *
98 * XXX(hch): the second argument is sometimes 0 and sometimes
99 * geo->datablk
100 */
101 dot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
102 dp->d_ops->data_dot_offset);
103 dotdot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
104 dp->d_ops->data_dotdot_offset);
105
106 /*
107 * Put . entry unless we're starting past it.
108 */
109 if (ctx->pos <= dot_offset) {
110 ctx->pos = dot_offset & 0x7fffffff;
111 if (!dir_emit(ctx, ".", 1, dp->i_ino, DT_DIR))
112 return 0;
113 }
114
115 /*
116 * Put .. entry unless we're starting past it.
117 */
118 if (ctx->pos <= dotdot_offset) {
119 ino = dp->d_ops->sf_get_parent_ino(sfp);
120 ctx->pos = dotdot_offset & 0x7fffffff;
121 if (!dir_emit(ctx, "..", 2, ino, DT_DIR))
122 return 0;
123 }
124
125 /*
126 * Loop while there are more entries and put'ing works.
127 */
128 sfep = xfs_dir2_sf_firstentry(sfp);
129 for (i = 0; i < sfp->count; i++) {
130 __uint8_t filetype;
131
132 off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
133 xfs_dir2_sf_get_offset(sfep));
134
135 if (ctx->pos > off) {
136 sfep = dp->d_ops->sf_nextentry(sfp, sfep);
137 continue;
138 }
139
140 ino = dp->d_ops->sf_get_ino(sfp, sfep);
141 filetype = dp->d_ops->sf_get_ftype(sfep);
142 ctx->pos = off & 0x7fffffff;
143 if (!dir_emit(ctx, (char *)sfep->name, sfep->namelen, ino,
144 xfs_dir3_get_dtype(dp->i_mount, filetype)))
145 return 0;
146 sfep = dp->d_ops->sf_nextentry(sfp, sfep);
147 }
148
149 ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &
150 0x7fffffff;
151 return 0;
152}
153
154/*
155 * Readdir for block directories.
156 */
157STATIC int
158xfs_dir2_block_getdents(
159 struct xfs_da_args *args,
160 struct dir_context *ctx)
161{
162 struct xfs_inode *dp = args->dp; /* incore directory inode */
163 xfs_dir2_data_hdr_t *hdr; /* block header */
164 struct xfs_buf *bp; /* buffer for block */
165 xfs_dir2_block_tail_t *btp; /* block tail */
166 xfs_dir2_data_entry_t *dep; /* block data entry */
167 xfs_dir2_data_unused_t *dup; /* block unused entry */
168 char *endptr; /* end of the data entries */
169 int error; /* error return value */
170 char *ptr; /* current data entry */
171 int wantoff; /* starting block offset */
172 xfs_off_t cook;
173 struct xfs_da_geometry *geo = args->geo;
174 int lock_mode;
175
176 /*
177 * If the block number in the offset is out of range, we're done.
178 */
179 if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
180 return 0;
181
182 lock_mode = xfs_ilock_data_map_shared(dp);
183 error = xfs_dir3_block_read(NULL, dp, &bp);
184 xfs_iunlock(dp, lock_mode);
185 if (error)
186 return error;
187
188 /*
189 * Extract the byte offset we start at from the seek pointer.
190 * We'll skip entries before this.
191 */
192 wantoff = xfs_dir2_dataptr_to_off(geo, ctx->pos);
193 hdr = bp->b_addr;
194 xfs_dir3_data_check(dp, bp);
195 /*
196 * Set up values for the loop.
197 */
198 btp = xfs_dir2_block_tail_p(geo, hdr);
199 ptr = (char *)dp->d_ops->data_entry_p(hdr);
200 endptr = (char *)xfs_dir2_block_leaf_p(btp);
201
202 /*
203 * Loop over the data portion of the block.
204 * Each object is a real entry (dep) or an unused one (dup).
205 */
206 while (ptr < endptr) {
207 __uint8_t filetype;
208
209 dup = (xfs_dir2_data_unused_t *)ptr;
210 /*
211 * Unused, skip it.
212 */
213 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
214 ptr += be16_to_cpu(dup->length);
215 continue;
216 }
217
218 dep = (xfs_dir2_data_entry_t *)ptr;
219
220 /*
221 * Bump pointer for the next iteration.
222 */
223 ptr += dp->d_ops->data_entsize(dep->namelen);
224 /*
225 * The entry is before the desired starting point, skip it.
226 */
227 if ((char *)dep - (char *)hdr < wantoff)
228 continue;
229
230 cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
231 (char *)dep - (char *)hdr);
232
233 ctx->pos = cook & 0x7fffffff;
234 filetype = dp->d_ops->data_get_ftype(dep);
235 /*
236 * If it didn't fit, set the final offset to here & return.
237 */
238 if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
239 be64_to_cpu(dep->inumber),
240 xfs_dir3_get_dtype(dp->i_mount, filetype))) {
241 xfs_trans_brelse(NULL, bp);
242 return 0;
243 }
244 }
245
246 /*
247 * Reached the end of the block.
248 * Set the offset to a non-existent block 1 and return.
249 */
250 ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &
251 0x7fffffff;
252 xfs_trans_brelse(NULL, bp);
253 return 0;
254}
255
256struct xfs_dir2_leaf_map_info {
257 xfs_extlen_t map_blocks; /* number of fsbs in map */
258 xfs_dablk_t map_off; /* last mapped file offset */
259 int map_size; /* total entries in *map */
260 int map_valid; /* valid entries in *map */
261 int nmap; /* mappings to ask xfs_bmapi */
262 xfs_dir2_db_t curdb; /* db for current block */
263 int ra_current; /* number of read-ahead blks */
264 int ra_index; /* *map index for read-ahead */
265 int ra_offset; /* map entry offset for ra */
266 int ra_want; /* readahead count wanted */
267 struct xfs_bmbt_irec map[]; /* map vector for blocks */
268};
269
270STATIC int
271xfs_dir2_leaf_readbuf(
272 struct xfs_da_args *args,
273 size_t bufsize,
274 struct xfs_dir2_leaf_map_info *mip,
275 xfs_dir2_off_t *curoff,
276 struct xfs_buf **bpp)
277{
278 struct xfs_inode *dp = args->dp;
279 struct xfs_buf *bp = *bpp;
280 struct xfs_bmbt_irec *map = mip->map;
281 struct blk_plug plug;
282 int error = 0;
283 int length;
284 int i;
285 int j;
286 struct xfs_da_geometry *geo = args->geo;
287
288 /*
289 * If we have a buffer, we need to release it and
290 * take it out of the mapping.
291 */
292
293 if (bp) {
294 xfs_trans_brelse(NULL, bp);
295 bp = NULL;
296 mip->map_blocks -= geo->fsbcount;
297 /*
298 * Loop to get rid of the extents for the
299 * directory block.
300 */
301 for (i = geo->fsbcount; i > 0; ) {
302 j = min_t(int, map->br_blockcount, i);
303 map->br_blockcount -= j;
304 map->br_startblock += j;
305 map->br_startoff += j;
306 /*
307 * If mapping is done, pitch it from
308 * the table.
309 */
310 if (!map->br_blockcount && --mip->map_valid)
311 memmove(&map[0], &map[1],
312 sizeof(map[0]) * mip->map_valid);
313 i -= j;
314 }
315 }
316
317 /*
318 * Recalculate the readahead blocks wanted.
319 */
320 mip->ra_want = howmany(bufsize + geo->blksize, (1 << geo->fsblog)) - 1;
321 ASSERT(mip->ra_want >= 0);
322
323 /*
324 * If we don't have as many as we want, and we haven't
325 * run out of data blocks, get some more mappings.
326 */
327 if (1 + mip->ra_want > mip->map_blocks &&
328 mip->map_off < xfs_dir2_byte_to_da(geo, XFS_DIR2_LEAF_OFFSET)) {
329 /*
330 * Get more bmaps, fill in after the ones
331 * we already have in the table.
332 */
333 mip->nmap = mip->map_size - mip->map_valid;
334 error = xfs_bmapi_read(dp, mip->map_off,
335 xfs_dir2_byte_to_da(geo, XFS_DIR2_LEAF_OFFSET) -
336 mip->map_off,
337 &map[mip->map_valid], &mip->nmap, 0);
338
339 /*
340 * Don't know if we should ignore this or try to return an
341 * error. The trouble with returning errors is that readdir
342 * will just stop without actually passing the error through.
343 */
344 if (error)
345 goto out; /* XXX */
346
347 /*
348 * If we got all the mappings we asked for, set the final map
349 * offset based on the last bmap value received. Otherwise,
350 * we've reached the end.
351 */
352 if (mip->nmap == mip->map_size - mip->map_valid) {
353 i = mip->map_valid + mip->nmap - 1;
354 mip->map_off = map[i].br_startoff + map[i].br_blockcount;
355 } else
356 mip->map_off = xfs_dir2_byte_to_da(geo,
357 XFS_DIR2_LEAF_OFFSET);
358
359 /*
360 * Look for holes in the mapping, and eliminate them. Count up
361 * the valid blocks.
362 */
363 for (i = mip->map_valid; i < mip->map_valid + mip->nmap; ) {
364 if (map[i].br_startblock == HOLESTARTBLOCK) {
365 mip->nmap--;
366 length = mip->map_valid + mip->nmap - i;
367 if (length)
368 memmove(&map[i], &map[i + 1],
369 sizeof(map[i]) * length);
370 } else {
371 mip->map_blocks += map[i].br_blockcount;
372 i++;
373 }
374 }
375 mip->map_valid += mip->nmap;
376 }
377
378 /*
379 * No valid mappings, so no more data blocks.
380 */
381 if (!mip->map_valid) {
382 *curoff = xfs_dir2_da_to_byte(geo, mip->map_off);
383 goto out;
384 }
385
386 /*
387 * Read the directory block starting at the first mapping.
388 */
389 mip->curdb = xfs_dir2_da_to_db(geo, map->br_startoff);
390 error = xfs_dir3_data_read(NULL, dp, map->br_startoff,
391 map->br_blockcount >= geo->fsbcount ?
392 XFS_FSB_TO_DADDR(dp->i_mount, map->br_startblock) :
393 -1, &bp);
394 /*
395 * Should just skip over the data block instead of giving up.
396 */
397 if (error)
398 goto out; /* XXX */
399
400 /*
401 * Adjust the current amount of read-ahead: we just read a block that
402 * was previously ra.
403 */
404 if (mip->ra_current)
405 mip->ra_current -= geo->fsbcount;
406
407 /*
408 * Do we need more readahead?
409 */
410 blk_start_plug(&plug);
411 for (mip->ra_index = mip->ra_offset = i = 0;
412 mip->ra_want > mip->ra_current && i < mip->map_blocks;
413 i += geo->fsbcount) {
414 ASSERT(mip->ra_index < mip->map_valid);
415 /*
416 * Read-ahead a contiguous directory block.
417 */
418 if (i > mip->ra_current &&
419 map[mip->ra_index].br_blockcount >= geo->fsbcount) {
420 xfs_dir3_data_readahead(dp,
421 map[mip->ra_index].br_startoff + mip->ra_offset,
422 XFS_FSB_TO_DADDR(dp->i_mount,
423 map[mip->ra_index].br_startblock +
424 mip->ra_offset));
425 mip->ra_current = i;
426 }
427
428 /*
429 * Read-ahead a non-contiguous directory block. This doesn't
430 * use our mapping, but this is a very rare case.
431 */
432 else if (i > mip->ra_current) {
433 xfs_dir3_data_readahead(dp,
434 map[mip->ra_index].br_startoff +
435 mip->ra_offset, -1);
436 mip->ra_current = i;
437 }
438
439 /*
440 * Advance offset through the mapping table.
441 */
442 for (j = 0; j < geo->fsbcount; j += length ) {
443 /*
444 * The rest of this extent but not more than a dir
445 * block.
446 */
447 length = min_t(int, geo->fsbcount,
448 map[mip->ra_index].br_blockcount -
449 mip->ra_offset);
450 mip->ra_offset += length;
451
452 /*
453 * Advance to the next mapping if this one is used up.
454 */
455 if (mip->ra_offset == map[mip->ra_index].br_blockcount) {
456 mip->ra_offset = 0;
457 mip->ra_index++;
458 }
459 }
460 }
461 blk_finish_plug(&plug);
462
463out:
464 *bpp = bp;
465 return error;
466}
467
468/*
469 * Getdents (readdir) for leaf and node directories.
470 * This reads the data blocks only, so is the same for both forms.
471 */
472STATIC int
473xfs_dir2_leaf_getdents(
474 struct xfs_da_args *args,
475 struct dir_context *ctx,
476 size_t bufsize)
477{
478 struct xfs_inode *dp = args->dp;
479 struct xfs_buf *bp = NULL; /* data block buffer */
480 xfs_dir2_data_hdr_t *hdr; /* data block header */
481 xfs_dir2_data_entry_t *dep; /* data entry */
482 xfs_dir2_data_unused_t *dup; /* unused entry */
483 int error = 0; /* error return value */
484 int length; /* temporary length value */
485 int byteoff; /* offset in current block */
486 xfs_dir2_off_t curoff; /* current overall offset */
487 xfs_dir2_off_t newoff; /* new curoff after new blk */
488 char *ptr = NULL; /* pointer to current data */
489 struct xfs_dir2_leaf_map_info *map_info;
490 struct xfs_da_geometry *geo = args->geo;
491
492 /*
493 * If the offset is at or past the largest allowed value,
494 * give up right away.
495 */
496 if (ctx->pos >= XFS_DIR2_MAX_DATAPTR)
497 return 0;
498
499 /*
500 * Set up to bmap a number of blocks based on the caller's
501 * buffer size, the directory block size, and the filesystem
502 * block size.
503 */
504 length = howmany(bufsize + geo->blksize, (1 << geo->fsblog));
505 map_info = kmem_zalloc(offsetof(struct xfs_dir2_leaf_map_info, map) +
506 (length * sizeof(struct xfs_bmbt_irec)),
507 KM_SLEEP | KM_NOFS);
508 map_info->map_size = length;
509
510 /*
511 * Inside the loop we keep the main offset value as a byte offset
512 * in the directory file.
513 */
514 curoff = xfs_dir2_dataptr_to_byte(ctx->pos);
515
516 /*
517 * Force this conversion through db so we truncate the offset
518 * down to get the start of the data block.
519 */
520 map_info->map_off = xfs_dir2_db_to_da(geo,
521 xfs_dir2_byte_to_db(geo, curoff));
522
523 /*
524 * Loop over directory entries until we reach the end offset.
525 * Get more blocks and readahead as necessary.
526 */
527 while (curoff < XFS_DIR2_LEAF_OFFSET) {
528 __uint8_t filetype;
529
530 /*
531 * If we have no buffer, or we're off the end of the
532 * current buffer, need to get another one.
533 */
534 if (!bp || ptr >= (char *)bp->b_addr + geo->blksize) {
535 int lock_mode;
536
537 lock_mode = xfs_ilock_data_map_shared(dp);
538 error = xfs_dir2_leaf_readbuf(args, bufsize, map_info,
539 &curoff, &bp);
540 xfs_iunlock(dp, lock_mode);
541 if (error || !map_info->map_valid)
542 break;
543
544 /*
545 * Having done a read, we need to set a new offset.
546 */
547 newoff = xfs_dir2_db_off_to_byte(geo,
548 map_info->curdb, 0);
549 /*
550 * Start of the current block.
551 */
552 if (curoff < newoff)
553 curoff = newoff;
554 /*
555 * Make sure we're in the right block.
556 */
557 else if (curoff > newoff)
558 ASSERT(xfs_dir2_byte_to_db(geo, curoff) ==
559 map_info->curdb);
560 hdr = bp->b_addr;
561 xfs_dir3_data_check(dp, bp);
562 /*
563 * Find our position in the block.
564 */
565 ptr = (char *)dp->d_ops->data_entry_p(hdr);
566 byteoff = xfs_dir2_byte_to_off(geo, curoff);
567 /*
568 * Skip past the header.
569 */
570 if (byteoff == 0)
571 curoff += dp->d_ops->data_entry_offset;
572 /*
573 * Skip past entries until we reach our offset.
574 */
575 else {
576 while ((char *)ptr - (char *)hdr < byteoff) {
577 dup = (xfs_dir2_data_unused_t *)ptr;
578
579 if (be16_to_cpu(dup->freetag)
580 == XFS_DIR2_DATA_FREE_TAG) {
581
582 length = be16_to_cpu(dup->length);
583 ptr += length;
584 continue;
585 }
586 dep = (xfs_dir2_data_entry_t *)ptr;
587 length =
588 dp->d_ops->data_entsize(dep->namelen);
589 ptr += length;
590 }
591 /*
592 * Now set our real offset.
593 */
594 curoff =
595 xfs_dir2_db_off_to_byte(geo,
596 xfs_dir2_byte_to_db(geo, curoff),
597 (char *)ptr - (char *)hdr);
598 if (ptr >= (char *)hdr + geo->blksize) {
599 continue;
600 }
601 }
602 }
603 /*
604 * We have a pointer to an entry.
605 * Is it a live one?
606 */
607 dup = (xfs_dir2_data_unused_t *)ptr;
608 /*
609 * No, it's unused, skip over it.
610 */
611 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
612 length = be16_to_cpu(dup->length);
613 ptr += length;
614 curoff += length;
615 continue;
616 }
617
618 dep = (xfs_dir2_data_entry_t *)ptr;
619 length = dp->d_ops->data_entsize(dep->namelen);
620 filetype = dp->d_ops->data_get_ftype(dep);
621
622 ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
623 if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
624 be64_to_cpu(dep->inumber),
625 xfs_dir3_get_dtype(dp->i_mount, filetype)))
626 break;
627
628 /*
629 * Advance to next entry in the block.
630 */
631 ptr += length;
632 curoff += length;
633 /* bufsize may have just been a guess; don't go negative */
634 bufsize = bufsize > length ? bufsize - length : 0;
635 }
636
637 /*
638 * All done. Set output offset value to current offset.
639 */
640 if (curoff > xfs_dir2_dataptr_to_byte(XFS_DIR2_MAX_DATAPTR))
641 ctx->pos = XFS_DIR2_MAX_DATAPTR & 0x7fffffff;
642 else
643 ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
644 kmem_free(map_info);
645 if (bp)
646 xfs_trans_brelse(NULL, bp);
647 return error;
648}
649
650/*
651 * Read a directory.
652 */
653int
654xfs_readdir(
655 struct xfs_inode *dp,
656 struct dir_context *ctx,
657 size_t bufsize)
658{
659 struct xfs_da_args args = { NULL };
660 int rval;
661 int v;
662
663 trace_xfs_readdir(dp);
664
665 if (XFS_FORCED_SHUTDOWN(dp->i_mount))
666 return -EIO;
667
668 ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
669 XFS_STATS_INC(dp->i_mount, xs_dir_getdents);
670
671 args.dp = dp;
672 args.geo = dp->i_mount->m_dir_geo;
673
674 xfs_ilock(dp, XFS_IOLOCK_SHARED);
675 if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
676 rval = xfs_dir2_sf_getdents(&args, ctx);
677 else if ((rval = xfs_dir2_isblock(&args, &v)))
678 ;
679 else if (v)
680 rval = xfs_dir2_block_getdents(&args, ctx);
681 else
682 rval = xfs_dir2_leaf_getdents(&args, ctx, bufsize);
683 xfs_iunlock(dp, XFS_IOLOCK_SHARED);
684
685 return rval;
686}
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 */
26static 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
31unsigned char
32xfs_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
45STATIC int
46xfs_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, ".", 1, 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, "..", 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 */
139STATIC int
140xfs_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, args->owner, &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, (char *)dep->name, dep->namelen,
221 be64_to_cpu(dep->inumber),
222 xfs_dir3_get_dtype(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;
232out_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 */
242STATIC int
243xfs_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, args->owner,
286 map.br_startoff, 0, &bp);
287 if (error)
288 goto out;
289
290 /*
291 * Start readahead for the next bufsize's worth of dir data blocks.
292 * We may have already issued readahead for some of that range;
293 * ra_blk tracks the last block we tried to read(ahead).
294 */
295 ra_want = howmany(bufsize + geo->blksize, (1 << geo->fsblog));
296 if (*ra_blk >= last_da)
297 goto out;
298 else if (*ra_blk == 0)
299 *ra_blk = map.br_startoff;
300 next_ra = map.br_startoff + geo->fsbcount;
301 if (next_ra >= last_da)
302 goto out_no_ra;
303 if (map.br_blockcount < geo->fsbcount &&
304 !xfs_iext_next_extent(ifp, &icur, &map))
305 goto out_no_ra;
306 if (map.br_startoff >= last_da)
307 goto out_no_ra;
308 xfs_trim_extent(&map, next_ra, last_da - next_ra);
309
310 /* Start ra for each dir (not fs) block that has a mapping. */
311 blk_start_plug(&plug);
312 while (ra_want > 0) {
313 next_ra = roundup((xfs_dablk_t)map.br_startoff, geo->fsbcount);
314 while (ra_want > 0 &&
315 next_ra < map.br_startoff + map.br_blockcount) {
316 if (next_ra >= last_da) {
317 *ra_blk = last_da;
318 break;
319 }
320 if (next_ra > *ra_blk) {
321 xfs_dir3_data_readahead(dp, next_ra,
322 XFS_DABUF_MAP_HOLE_OK);
323 *ra_blk = next_ra;
324 }
325 ra_want -= geo->fsbcount;
326 next_ra += geo->fsbcount;
327 }
328 if (!xfs_iext_next_extent(ifp, &icur, &map)) {
329 *ra_blk = last_da;
330 break;
331 }
332 }
333 blk_finish_plug(&plug);
334
335out:
336 *bpp = bp;
337 return error;
338out_no_ra:
339 *ra_blk = last_da;
340 goto out;
341}
342
343/*
344 * Getdents (readdir) for leaf and node directories.
345 * This reads the data blocks only, so is the same for both forms.
346 */
347STATIC int
348xfs_dir2_leaf_getdents(
349 struct xfs_da_args *args,
350 struct dir_context *ctx,
351 size_t bufsize,
352 unsigned int *lock_mode)
353{
354 struct xfs_inode *dp = args->dp;
355 struct xfs_mount *mp = dp->i_mount;
356 struct xfs_buf *bp = NULL; /* data block buffer */
357 xfs_dir2_data_entry_t *dep; /* data entry */
358 xfs_dir2_data_unused_t *dup; /* unused entry */
359 struct xfs_da_geometry *geo = args->geo;
360 xfs_dablk_t rablk = 0; /* current readahead block */
361 xfs_dir2_off_t curoff; /* current overall offset */
362 int length; /* temporary length value */
363 int byteoff; /* offset in current block */
364 unsigned int offset = 0;
365 int error = 0; /* error return value */
366
367 /*
368 * If the offset is at or past the largest allowed value,
369 * give up right away.
370 */
371 if (ctx->pos >= XFS_DIR2_MAX_DATAPTR)
372 return 0;
373
374 /*
375 * Inside the loop we keep the main offset value as a byte offset
376 * in the directory file.
377 */
378 curoff = xfs_dir2_dataptr_to_byte(ctx->pos);
379
380 /*
381 * Loop over directory entries until we reach the end offset.
382 * Get more blocks and readahead as necessary.
383 */
384 while (curoff < XFS_DIR2_LEAF_OFFSET) {
385 uint8_t filetype;
386
387 /*
388 * If we have no buffer, or we're off the end of the
389 * current buffer, need to get another one.
390 */
391 if (!bp || offset >= geo->blksize) {
392 if (bp) {
393 xfs_trans_brelse(args->trans, bp);
394 bp = NULL;
395 }
396
397 if (*lock_mode == 0)
398 *lock_mode = xfs_ilock_data_map_shared(dp);
399 error = xfs_dir2_leaf_readbuf(args, bufsize, &curoff,
400 &rablk, &bp);
401 if (error || !bp)
402 break;
403
404 xfs_iunlock(dp, *lock_mode);
405 *lock_mode = 0;
406
407 xfs_dir3_data_check(dp, bp);
408 /*
409 * Find our position in the block.
410 */
411 offset = geo->data_entry_offset;
412 byteoff = xfs_dir2_byte_to_off(geo, curoff);
413 /*
414 * Skip past the header.
415 */
416 if (byteoff == 0)
417 curoff += geo->data_entry_offset;
418 /*
419 * Skip past entries until we reach our offset.
420 */
421 else {
422 while (offset < byteoff) {
423 dup = bp->b_addr + offset;
424
425 if (be16_to_cpu(dup->freetag)
426 == XFS_DIR2_DATA_FREE_TAG) {
427
428 length = be16_to_cpu(dup->length);
429 offset += length;
430 continue;
431 }
432 dep = bp->b_addr + offset;
433 length = xfs_dir2_data_entsize(mp,
434 dep->namelen);
435 offset += length;
436 }
437 /*
438 * Now set our real offset.
439 */
440 curoff =
441 xfs_dir2_db_off_to_byte(geo,
442 xfs_dir2_byte_to_db(geo, curoff),
443 offset);
444 if (offset >= geo->blksize)
445 continue;
446 }
447 }
448
449 /*
450 * We have a pointer to an entry. Is it a live one?
451 */
452 dup = bp->b_addr + offset;
453
454 /*
455 * No, it's unused, skip over it.
456 */
457 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
458 length = be16_to_cpu(dup->length);
459 offset += length;
460 curoff += length;
461 continue;
462 }
463
464 dep = bp->b_addr + offset;
465 length = xfs_dir2_data_entsize(mp, dep->namelen);
466 filetype = xfs_dir2_data_get_ftype(mp, dep);
467
468 ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
469 if (XFS_IS_CORRUPT(dp->i_mount,
470 !xfs_dir2_namecheck(dep->name,
471 dep->namelen))) {
472 xfs_dirattr_mark_sick(dp, XFS_DATA_FORK);
473 error = -EFSCORRUPTED;
474 break;
475 }
476 if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
477 be64_to_cpu(dep->inumber),
478 xfs_dir3_get_dtype(dp->i_mount, filetype)))
479 break;
480
481 /*
482 * Advance to next entry in the block.
483 */
484 offset += length;
485 curoff += length;
486 /* bufsize may have just been a guess; don't go negative */
487 bufsize = bufsize > length ? bufsize - length : 0;
488 }
489
490 /*
491 * All done. Set output offset value to current offset.
492 */
493 if (curoff > xfs_dir2_dataptr_to_byte(XFS_DIR2_MAX_DATAPTR))
494 ctx->pos = XFS_DIR2_MAX_DATAPTR & 0x7fffffff;
495 else
496 ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
497 if (bp)
498 xfs_trans_brelse(args->trans, bp);
499 return error;
500}
501
502/*
503 * Read a directory.
504 *
505 * If supplied, the transaction collects locked dir buffers to avoid
506 * nested buffer deadlocks. This function does not dirty the
507 * transaction. The caller must hold the IOLOCK (shared or exclusive)
508 * before calling this function.
509 */
510int
511xfs_readdir(
512 struct xfs_trans *tp,
513 struct xfs_inode *dp,
514 struct dir_context *ctx,
515 size_t bufsize)
516{
517 struct xfs_da_args args = { NULL };
518 unsigned int lock_mode;
519 int error;
520
521 trace_xfs_readdir(dp);
522
523 if (xfs_is_shutdown(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 args.owner = dp->i_ino;
536
537 if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL)
538 return xfs_dir2_sf_getdents(&args, ctx);
539
540 lock_mode = xfs_ilock_data_map_shared(dp);
541 switch (xfs_dir2_format(&args, &error)) {
542 case XFS_DIR2_FMT_BLOCK:
543 error = xfs_dir2_block_getdents(&args, ctx, &lock_mode);
544 break;
545 case XFS_DIR2_FMT_LEAF:
546 case XFS_DIR2_FMT_NODE:
547 error = xfs_dir2_leaf_getdents(&args, ctx, bufsize, &lock_mode);
548 break;
549 default:
550 break;
551 }
552
553 if (lock_mode)
554 xfs_iunlock(dp, lock_mode);
555 return error;
556}