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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
22/*
23 * Directory file type support functions
24 */
25static unsigned char xfs_dir3_filetype_table[] = {
26 DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK,
27 DT_FIFO, DT_SOCK, DT_LNK, DT_WHT,
28};
29
30unsigned char
31xfs_dir3_get_dtype(
32 struct xfs_mount *mp,
33 uint8_t filetype)
34{
35 if (!xfs_sb_version_hasftype(&mp->m_sb))
36 return DT_UNKNOWN;
37
38 if (filetype >= XFS_DIR3_FT_MAX)
39 return DT_UNKNOWN;
40
41 return xfs_dir3_filetype_table[filetype];
42}
43
44STATIC int
45xfs_dir2_sf_getdents(
46 struct xfs_da_args *args,
47 struct dir_context *ctx)
48{
49 int i; /* shortform entry number */
50 struct xfs_inode *dp = args->dp; /* incore directory inode */
51 struct xfs_mount *mp = dp->i_mount;
52 xfs_dir2_dataptr_t off; /* current entry's offset */
53 xfs_dir2_sf_entry_t *sfep; /* shortform directory entry */
54 xfs_dir2_sf_hdr_t *sfp; /* shortform structure */
55 xfs_dir2_dataptr_t dot_offset;
56 xfs_dir2_dataptr_t dotdot_offset;
57 xfs_ino_t ino;
58 struct xfs_da_geometry *geo = args->geo;
59
60 ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
61 ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
62 ASSERT(dp->i_df.if_u1.if_data != NULL);
63
64 sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
65
66 /*
67 * If the block number in the offset is out of range, we're done.
68 */
69 if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
70 return 0;
71
72 /*
73 * Precalculate offsets for "." and ".." as we will always need them.
74 * This relies on the fact that directories always start with the
75 * entries for "." and "..".
76 */
77 dot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
78 geo->data_entry_offset);
79 dotdot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
80 geo->data_entry_offset +
81 xfs_dir2_data_entsize(mp, sizeof(".") - 1));
82
83 /*
84 * Put . entry unless we're starting past it.
85 */
86 if (ctx->pos <= dot_offset) {
87 ctx->pos = dot_offset & 0x7fffffff;
88 if (!dir_emit(ctx, ".", 1, dp->i_ino, DT_DIR))
89 return 0;
90 }
91
92 /*
93 * Put .. entry unless we're starting past it.
94 */
95 if (ctx->pos <= dotdot_offset) {
96 ino = xfs_dir2_sf_get_parent_ino(sfp);
97 ctx->pos = dotdot_offset & 0x7fffffff;
98 if (!dir_emit(ctx, "..", 2, ino, DT_DIR))
99 return 0;
100 }
101
102 /*
103 * Loop while there are more entries and put'ing works.
104 */
105 sfep = xfs_dir2_sf_firstentry(sfp);
106 for (i = 0; i < sfp->count; i++) {
107 uint8_t filetype;
108
109 off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
110 xfs_dir2_sf_get_offset(sfep));
111
112 if (ctx->pos > off) {
113 sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep);
114 continue;
115 }
116
117 ino = xfs_dir2_sf_get_ino(mp, sfp, sfep);
118 filetype = xfs_dir2_sf_get_ftype(mp, sfep);
119 ctx->pos = off & 0x7fffffff;
120 if (XFS_IS_CORRUPT(dp->i_mount,
121 !xfs_dir2_namecheck(sfep->name,
122 sfep->namelen)))
123 return -EFSCORRUPTED;
124 if (!dir_emit(ctx, (char *)sfep->name, sfep->namelen, ino,
125 xfs_dir3_get_dtype(mp, filetype)))
126 return 0;
127 sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep);
128 }
129
130 ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &
131 0x7fffffff;
132 return 0;
133}
134
135/*
136 * Readdir for block directories.
137 */
138STATIC int
139xfs_dir2_block_getdents(
140 struct xfs_da_args *args,
141 struct dir_context *ctx)
142{
143 struct xfs_inode *dp = args->dp; /* incore directory inode */
144 struct xfs_buf *bp; /* buffer for block */
145 int error; /* error return value */
146 int wantoff; /* starting block offset */
147 xfs_off_t cook;
148 struct xfs_da_geometry *geo = args->geo;
149 int lock_mode;
150 unsigned int offset, next_offset;
151 unsigned int end;
152
153 /*
154 * If the block number in the offset is out of range, we're done.
155 */
156 if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
157 return 0;
158
159 lock_mode = xfs_ilock_data_map_shared(dp);
160 error = xfs_dir3_block_read(args->trans, dp, &bp);
161 xfs_iunlock(dp, lock_mode);
162 if (error)
163 return error;
164
165 /*
166 * Extract the byte offset we start at from the seek pointer.
167 * We'll skip entries before this.
168 */
169 wantoff = xfs_dir2_dataptr_to_off(geo, ctx->pos);
170 xfs_dir3_data_check(dp, bp);
171
172 /*
173 * Loop over the data portion of the block.
174 * Each object is a real entry (dep) or an unused one (dup).
175 */
176 end = xfs_dir3_data_end_offset(geo, bp->b_addr);
177 for (offset = geo->data_entry_offset;
178 offset < end;
179 offset = next_offset) {
180 struct xfs_dir2_data_unused *dup = bp->b_addr + offset;
181 struct xfs_dir2_data_entry *dep = bp->b_addr + offset;
182 uint8_t filetype;
183
184 /*
185 * Unused, skip it.
186 */
187 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
188 next_offset = offset + be16_to_cpu(dup->length);
189 continue;
190 }
191
192 /*
193 * Bump pointer for the next iteration.
194 */
195 next_offset = offset +
196 xfs_dir2_data_entsize(dp->i_mount, dep->namelen);
197
198 /*
199 * The entry is before the desired starting point, skip it.
200 */
201 if (offset < wantoff)
202 continue;
203
204 cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, offset);
205
206 ctx->pos = cook & 0x7fffffff;
207 filetype = xfs_dir2_data_get_ftype(dp->i_mount, dep);
208 /*
209 * If it didn't fit, set the final offset to here & return.
210 */
211 if (XFS_IS_CORRUPT(dp->i_mount,
212 !xfs_dir2_namecheck(dep->name,
213 dep->namelen))) {
214 error = -EFSCORRUPTED;
215 goto out_rele;
216 }
217 if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
218 be64_to_cpu(dep->inumber),
219 xfs_dir3_get_dtype(dp->i_mount, filetype)))
220 goto out_rele;
221 }
222
223 /*
224 * Reached the end of the block.
225 * Set the offset to a non-existent block 1 and return.
226 */
227 ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &
228 0x7fffffff;
229out_rele:
230 xfs_trans_brelse(args->trans, bp);
231 return error;
232}
233
234/*
235 * Read a directory block and initiate readahead for blocks beyond that.
236 * We maintain a sliding readahead window of the remaining space in the
237 * buffer rounded up to the nearest block.
238 */
239STATIC int
240xfs_dir2_leaf_readbuf(
241 struct xfs_da_args *args,
242 size_t bufsize,
243 xfs_dir2_off_t *cur_off,
244 xfs_dablk_t *ra_blk,
245 struct xfs_buf **bpp)
246{
247 struct xfs_inode *dp = args->dp;
248 struct xfs_buf *bp = NULL;
249 struct xfs_da_geometry *geo = args->geo;
250 struct xfs_ifork *ifp = XFS_IFORK_PTR(dp, XFS_DATA_FORK);
251 struct xfs_bmbt_irec map;
252 struct blk_plug plug;
253 xfs_dir2_off_t new_off;
254 xfs_dablk_t next_ra;
255 xfs_dablk_t map_off;
256 xfs_dablk_t last_da;
257 struct xfs_iext_cursor icur;
258 int ra_want;
259 int error = 0;
260
261 if (!(ifp->if_flags & XFS_IFEXTENTS)) {
262 error = xfs_iread_extents(args->trans, dp, XFS_DATA_FORK);
263 if (error)
264 goto out;
265 }
266
267 /*
268 * Look for mapped directory blocks at or above the current offset.
269 * Truncate down to the nearest directory block to start the scanning
270 * operation.
271 */
272 last_da = xfs_dir2_byte_to_da(geo, XFS_DIR2_LEAF_OFFSET);
273 map_off = xfs_dir2_db_to_da(geo, xfs_dir2_byte_to_db(geo, *cur_off));
274 if (!xfs_iext_lookup_extent(dp, ifp, map_off, &icur, &map))
275 goto out;
276 if (map.br_startoff >= last_da)
277 goto out;
278 xfs_trim_extent(&map, map_off, last_da - map_off);
279
280 /* Read the directory block of that first mapping. */
281 new_off = xfs_dir2_da_to_byte(geo, map.br_startoff);
282 if (new_off > *cur_off)
283 *cur_off = new_off;
284 error = xfs_dir3_data_read(args->trans, dp, map.br_startoff, 0, &bp);
285 if (error)
286 goto out;
287
288 /*
289 * Start readahead for the next bufsize's worth of dir data blocks.
290 * We may have already issued readahead for some of that range;
291 * ra_blk tracks the last block we tried to read(ahead).
292 */
293 ra_want = howmany(bufsize + geo->blksize, (1 << geo->fsblog));
294 if (*ra_blk >= last_da)
295 goto out;
296 else if (*ra_blk == 0)
297 *ra_blk = map.br_startoff;
298 next_ra = map.br_startoff + geo->fsbcount;
299 if (next_ra >= last_da)
300 goto out_no_ra;
301 if (map.br_blockcount < geo->fsbcount &&
302 !xfs_iext_next_extent(ifp, &icur, &map))
303 goto out_no_ra;
304 if (map.br_startoff >= last_da)
305 goto out_no_ra;
306 xfs_trim_extent(&map, next_ra, last_da - next_ra);
307
308 /* Start ra for each dir (not fs) block that has a mapping. */
309 blk_start_plug(&plug);
310 while (ra_want > 0) {
311 next_ra = roundup((xfs_dablk_t)map.br_startoff, geo->fsbcount);
312 while (ra_want > 0 &&
313 next_ra < map.br_startoff + map.br_blockcount) {
314 if (next_ra >= last_da) {
315 *ra_blk = last_da;
316 break;
317 }
318 if (next_ra > *ra_blk) {
319 xfs_dir3_data_readahead(dp, next_ra,
320 XFS_DABUF_MAP_HOLE_OK);
321 *ra_blk = next_ra;
322 }
323 ra_want -= geo->fsbcount;
324 next_ra += geo->fsbcount;
325 }
326 if (!xfs_iext_next_extent(ifp, &icur, &map)) {
327 *ra_blk = last_da;
328 break;
329 }
330 }
331 blk_finish_plug(&plug);
332
333out:
334 *bpp = bp;
335 return error;
336out_no_ra:
337 *ra_blk = last_da;
338 goto out;
339}
340
341/*
342 * Getdents (readdir) for leaf and node directories.
343 * This reads the data blocks only, so is the same for both forms.
344 */
345STATIC int
346xfs_dir2_leaf_getdents(
347 struct xfs_da_args *args,
348 struct dir_context *ctx,
349 size_t bufsize)
350{
351 struct xfs_inode *dp = args->dp;
352 struct xfs_mount *mp = dp->i_mount;
353 struct xfs_buf *bp = NULL; /* data block buffer */
354 xfs_dir2_data_entry_t *dep; /* data entry */
355 xfs_dir2_data_unused_t *dup; /* unused entry */
356 struct xfs_da_geometry *geo = args->geo;
357 xfs_dablk_t rablk = 0; /* current readahead block */
358 xfs_dir2_off_t curoff; /* current overall offset */
359 int length; /* temporary length value */
360 int byteoff; /* offset in current block */
361 int lock_mode;
362 unsigned int offset = 0;
363 int error = 0; /* error return value */
364
365 /*
366 * If the offset is at or past the largest allowed value,
367 * give up right away.
368 */
369 if (ctx->pos >= XFS_DIR2_MAX_DATAPTR)
370 return 0;
371
372 /*
373 * Inside the loop we keep the main offset value as a byte offset
374 * in the directory file.
375 */
376 curoff = xfs_dir2_dataptr_to_byte(ctx->pos);
377
378 /*
379 * Loop over directory entries until we reach the end offset.
380 * Get more blocks and readahead as necessary.
381 */
382 while (curoff < XFS_DIR2_LEAF_OFFSET) {
383 uint8_t filetype;
384
385 /*
386 * If we have no buffer, or we're off the end of the
387 * current buffer, need to get another one.
388 */
389 if (!bp || offset >= geo->blksize) {
390 if (bp) {
391 xfs_trans_brelse(args->trans, bp);
392 bp = NULL;
393 }
394
395 lock_mode = xfs_ilock_data_map_shared(dp);
396 error = xfs_dir2_leaf_readbuf(args, bufsize, &curoff,
397 &rablk, &bp);
398 xfs_iunlock(dp, lock_mode);
399 if (error || !bp)
400 break;
401
402 xfs_dir3_data_check(dp, bp);
403 /*
404 * Find our position in the block.
405 */
406 offset = geo->data_entry_offset;
407 byteoff = xfs_dir2_byte_to_off(geo, curoff);
408 /*
409 * Skip past the header.
410 */
411 if (byteoff == 0)
412 curoff += geo->data_entry_offset;
413 /*
414 * Skip past entries until we reach our offset.
415 */
416 else {
417 while (offset < byteoff) {
418 dup = bp->b_addr + offset;
419
420 if (be16_to_cpu(dup->freetag)
421 == XFS_DIR2_DATA_FREE_TAG) {
422
423 length = be16_to_cpu(dup->length);
424 offset += length;
425 continue;
426 }
427 dep = bp->b_addr + offset;
428 length = xfs_dir2_data_entsize(mp,
429 dep->namelen);
430 offset += length;
431 }
432 /*
433 * Now set our real offset.
434 */
435 curoff =
436 xfs_dir2_db_off_to_byte(geo,
437 xfs_dir2_byte_to_db(geo, curoff),
438 offset);
439 if (offset >= geo->blksize)
440 continue;
441 }
442 }
443
444 /*
445 * We have a pointer to an entry. Is it a live one?
446 */
447 dup = bp->b_addr + offset;
448
449 /*
450 * No, it's unused, skip over it.
451 */
452 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
453 length = be16_to_cpu(dup->length);
454 offset += length;
455 curoff += length;
456 continue;
457 }
458
459 dep = bp->b_addr + offset;
460 length = xfs_dir2_data_entsize(mp, dep->namelen);
461 filetype = xfs_dir2_data_get_ftype(mp, dep);
462
463 ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
464 if (XFS_IS_CORRUPT(dp->i_mount,
465 !xfs_dir2_namecheck(dep->name,
466 dep->namelen))) {
467 error = -EFSCORRUPTED;
468 break;
469 }
470 if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
471 be64_to_cpu(dep->inumber),
472 xfs_dir3_get_dtype(dp->i_mount, filetype)))
473 break;
474
475 /*
476 * Advance to next entry in the block.
477 */
478 offset += length;
479 curoff += length;
480 /* bufsize may have just been a guess; don't go negative */
481 bufsize = bufsize > length ? bufsize - length : 0;
482 }
483
484 /*
485 * All done. Set output offset value to current offset.
486 */
487 if (curoff > xfs_dir2_dataptr_to_byte(XFS_DIR2_MAX_DATAPTR))
488 ctx->pos = XFS_DIR2_MAX_DATAPTR & 0x7fffffff;
489 else
490 ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
491 if (bp)
492 xfs_trans_brelse(args->trans, bp);
493 return error;
494}
495
496/*
497 * Read a directory.
498 *
499 * If supplied, the transaction collects locked dir buffers to avoid
500 * nested buffer deadlocks. This function does not dirty the
501 * transaction. The caller should ensure that the inode is locked
502 * before calling this function.
503 */
504int
505xfs_readdir(
506 struct xfs_trans *tp,
507 struct xfs_inode *dp,
508 struct dir_context *ctx,
509 size_t bufsize)
510{
511 struct xfs_da_args args = { NULL };
512 int rval;
513 int v;
514
515 trace_xfs_readdir(dp);
516
517 if (XFS_FORCED_SHUTDOWN(dp->i_mount))
518 return -EIO;
519
520 ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
521 XFS_STATS_INC(dp->i_mount, xs_dir_getdents);
522
523 args.dp = dp;
524 args.geo = dp->i_mount->m_dir_geo;
525 args.trans = tp;
526
527 if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL)
528 rval = xfs_dir2_sf_getdents(&args, ctx);
529 else if ((rval = xfs_dir2_isblock(&args, &v)))
530 ;
531 else if (v)
532 rval = xfs_dir2_block_getdents(&args, ctx);
533 else
534 rval = xfs_dir2_leaf_getdents(&args, ctx, bufsize);
535
536 return rval;
537}
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 if (dp->i_d.di_size < xfs_dir2_sf_hdr_size(sfp->i8count))
88 return -EFSCORRUPTED;
89
90 /*
91 * If the block number in the offset is out of range, we're done.
92 */
93 if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
94 return 0;
95
96 /*
97 * Precalculate offsets for . and .. as we will always need them.
98 *
99 * XXX(hch): the second argument is sometimes 0 and sometimes
100 * geo->datablk
101 */
102 dot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
103 dp->d_ops->data_dot_offset);
104 dotdot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
105 dp->d_ops->data_dotdot_offset);
106
107 /*
108 * Put . entry unless we're starting past it.
109 */
110 if (ctx->pos <= dot_offset) {
111 ctx->pos = dot_offset & 0x7fffffff;
112 if (!dir_emit(ctx, ".", 1, dp->i_ino, DT_DIR))
113 return 0;
114 }
115
116 /*
117 * Put .. entry unless we're starting past it.
118 */
119 if (ctx->pos <= dotdot_offset) {
120 ino = dp->d_ops->sf_get_parent_ino(sfp);
121 ctx->pos = dotdot_offset & 0x7fffffff;
122 if (!dir_emit(ctx, "..", 2, ino, DT_DIR))
123 return 0;
124 }
125
126 /*
127 * Loop while there are more entries and put'ing works.
128 */
129 sfep = xfs_dir2_sf_firstentry(sfp);
130 for (i = 0; i < sfp->count; i++) {
131 __uint8_t filetype;
132
133 off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
134 xfs_dir2_sf_get_offset(sfep));
135
136 if (ctx->pos > off) {
137 sfep = dp->d_ops->sf_nextentry(sfp, sfep);
138 continue;
139 }
140
141 ino = dp->d_ops->sf_get_ino(sfp, sfep);
142 filetype = dp->d_ops->sf_get_ftype(sfep);
143 ctx->pos = off & 0x7fffffff;
144 if (!dir_emit(ctx, (char *)sfep->name, sfep->namelen, ino,
145 xfs_dir3_get_dtype(dp->i_mount, filetype)))
146 return 0;
147 sfep = dp->d_ops->sf_nextentry(sfp, sfep);
148 }
149
150 ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &
151 0x7fffffff;
152 return 0;
153}
154
155/*
156 * Readdir for block directories.
157 */
158STATIC int
159xfs_dir2_block_getdents(
160 struct xfs_da_args *args,
161 struct dir_context *ctx)
162{
163 struct xfs_inode *dp = args->dp; /* incore directory inode */
164 xfs_dir2_data_hdr_t *hdr; /* block header */
165 struct xfs_buf *bp; /* buffer for block */
166 xfs_dir2_block_tail_t *btp; /* block tail */
167 xfs_dir2_data_entry_t *dep; /* block data entry */
168 xfs_dir2_data_unused_t *dup; /* block unused entry */
169 char *endptr; /* end of the data entries */
170 int error; /* error return value */
171 char *ptr; /* current data entry */
172 int wantoff; /* starting block offset */
173 xfs_off_t cook;
174 struct xfs_da_geometry *geo = args->geo;
175 int lock_mode;
176
177 /*
178 * If the block number in the offset is out of range, we're done.
179 */
180 if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
181 return 0;
182
183 lock_mode = xfs_ilock_data_map_shared(dp);
184 error = xfs_dir3_block_read(NULL, dp, &bp);
185 xfs_iunlock(dp, lock_mode);
186 if (error)
187 return error;
188
189 /*
190 * Extract the byte offset we start at from the seek pointer.
191 * We'll skip entries before this.
192 */
193 wantoff = xfs_dir2_dataptr_to_off(geo, ctx->pos);
194 hdr = bp->b_addr;
195 xfs_dir3_data_check(dp, bp);
196 /*
197 * Set up values for the loop.
198 */
199 btp = xfs_dir2_block_tail_p(geo, hdr);
200 ptr = (char *)dp->d_ops->data_entry_p(hdr);
201 endptr = (char *)xfs_dir2_block_leaf_p(btp);
202
203 /*
204 * Loop over the data portion of the block.
205 * Each object is a real entry (dep) or an unused one (dup).
206 */
207 while (ptr < endptr) {
208 __uint8_t filetype;
209
210 dup = (xfs_dir2_data_unused_t *)ptr;
211 /*
212 * Unused, skip it.
213 */
214 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
215 ptr += be16_to_cpu(dup->length);
216 continue;
217 }
218
219 dep = (xfs_dir2_data_entry_t *)ptr;
220
221 /*
222 * Bump pointer for the next iteration.
223 */
224 ptr += dp->d_ops->data_entsize(dep->namelen);
225 /*
226 * The entry is before the desired starting point, skip it.
227 */
228 if ((char *)dep - (char *)hdr < wantoff)
229 continue;
230
231 cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
232 (char *)dep - (char *)hdr);
233
234 ctx->pos = cook & 0x7fffffff;
235 filetype = dp->d_ops->data_get_ftype(dep);
236 /*
237 * If it didn't fit, set the final offset to here & return.
238 */
239 if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
240 be64_to_cpu(dep->inumber),
241 xfs_dir3_get_dtype(dp->i_mount, filetype))) {
242 xfs_trans_brelse(NULL, bp);
243 return 0;
244 }
245 }
246
247 /*
248 * Reached the end of the block.
249 * Set the offset to a non-existent block 1 and return.
250 */
251 ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &
252 0x7fffffff;
253 xfs_trans_brelse(NULL, bp);
254 return 0;
255}
256
257struct xfs_dir2_leaf_map_info {
258 xfs_extlen_t map_blocks; /* number of fsbs in map */
259 xfs_dablk_t map_off; /* last mapped file offset */
260 int map_size; /* total entries in *map */
261 int map_valid; /* valid entries in *map */
262 int nmap; /* mappings to ask xfs_bmapi */
263 xfs_dir2_db_t curdb; /* db for current block */
264 int ra_current; /* number of read-ahead blks */
265 int ra_index; /* *map index for read-ahead */
266 int ra_offset; /* map entry offset for ra */
267 int ra_want; /* readahead count wanted */
268 struct xfs_bmbt_irec map[]; /* map vector for blocks */
269};
270
271STATIC int
272xfs_dir2_leaf_readbuf(
273 struct xfs_da_args *args,
274 size_t bufsize,
275 struct xfs_dir2_leaf_map_info *mip,
276 xfs_dir2_off_t *curoff,
277 struct xfs_buf **bpp,
278 bool trim_map)
279{
280 struct xfs_inode *dp = args->dp;
281 struct xfs_buf *bp = NULL;
282 struct xfs_bmbt_irec *map = mip->map;
283 struct blk_plug plug;
284 int error = 0;
285 int length;
286 int i;
287 int j;
288 struct xfs_da_geometry *geo = args->geo;
289
290 /*
291 * If the caller just finished processing a buffer, it will tell us
292 * we need to trim that block out of the mapping now it is done.
293 */
294 if (trim_map) {
295 mip->map_blocks -= geo->fsbcount;
296 /*
297 * Loop to get rid of the extents for the
298 * directory block.
299 */
300 for (i = geo->fsbcount; i > 0; ) {
301 j = min_t(int, map->br_blockcount, i);
302 map->br_blockcount -= j;
303 map->br_startblock += j;
304 map->br_startoff += j;
305 /*
306 * If mapping is done, pitch it from
307 * the table.
308 */
309 if (!map->br_blockcount && --mip->map_valid)
310 memmove(&map[0], &map[1],
311 sizeof(map[0]) * mip->map_valid);
312 i -= j;
313 }
314 }
315
316 /*
317 * Recalculate the readahead blocks wanted.
318 */
319 mip->ra_want = howmany(bufsize + geo->blksize, (1 << geo->fsblog)) - 1;
320 ASSERT(mip->ra_want >= 0);
321
322 /*
323 * If we don't have as many as we want, and we haven't
324 * run out of data blocks, get some more mappings.
325 */
326 if (1 + mip->ra_want > mip->map_blocks &&
327 mip->map_off < xfs_dir2_byte_to_da(geo, XFS_DIR2_LEAF_OFFSET)) {
328 /*
329 * Get more bmaps, fill in after the ones
330 * we already have in the table.
331 */
332 mip->nmap = mip->map_size - mip->map_valid;
333 error = xfs_bmapi_read(dp, mip->map_off,
334 xfs_dir2_byte_to_da(geo, XFS_DIR2_LEAF_OFFSET) -
335 mip->map_off,
336 &map[mip->map_valid], &mip->nmap, 0);
337
338 /*
339 * Don't know if we should ignore this or try to return an
340 * error. The trouble with returning errors is that readdir
341 * will just stop without actually passing the error through.
342 */
343 if (error)
344 goto out; /* XXX */
345
346 /*
347 * If we got all the mappings we asked for, set the final map
348 * offset based on the last bmap value received. Otherwise,
349 * we've reached the end.
350 */
351 if (mip->nmap == mip->map_size - mip->map_valid) {
352 i = mip->map_valid + mip->nmap - 1;
353 mip->map_off = map[i].br_startoff + map[i].br_blockcount;
354 } else
355 mip->map_off = xfs_dir2_byte_to_da(geo,
356 XFS_DIR2_LEAF_OFFSET);
357
358 /*
359 * Look for holes in the mapping, and eliminate them. Count up
360 * the valid blocks.
361 */
362 for (i = mip->map_valid; i < mip->map_valid + mip->nmap; ) {
363 if (map[i].br_startblock == HOLESTARTBLOCK) {
364 mip->nmap--;
365 length = mip->map_valid + mip->nmap - i;
366 if (length)
367 memmove(&map[i], &map[i + 1],
368 sizeof(map[i]) * length);
369 } else {
370 mip->map_blocks += map[i].br_blockcount;
371 i++;
372 }
373 }
374 mip->map_valid += mip->nmap;
375 }
376
377 /*
378 * No valid mappings, so no more data blocks.
379 */
380 if (!mip->map_valid) {
381 *curoff = xfs_dir2_da_to_byte(geo, mip->map_off);
382 goto out;
383 }
384
385 /*
386 * Read the directory block starting at the first mapping.
387 */
388 mip->curdb = xfs_dir2_da_to_db(geo, map->br_startoff);
389 error = xfs_dir3_data_read(NULL, dp, map->br_startoff,
390 map->br_blockcount >= geo->fsbcount ?
391 XFS_FSB_TO_DADDR(dp->i_mount, map->br_startblock) :
392 -1, &bp);
393 /*
394 * Should just skip over the data block instead of giving up.
395 */
396 if (error)
397 goto out; /* XXX */
398
399 /*
400 * Adjust the current amount of read-ahead: we just read a block that
401 * was previously ra.
402 */
403 if (mip->ra_current)
404 mip->ra_current -= geo->fsbcount;
405
406 /*
407 * Do we need more readahead?
408 */
409 blk_start_plug(&plug);
410 for (mip->ra_index = mip->ra_offset = i = 0;
411 mip->ra_want > mip->ra_current && i < mip->map_blocks;
412 i += geo->fsbcount) {
413 ASSERT(mip->ra_index < mip->map_valid);
414 /*
415 * Read-ahead a contiguous directory block.
416 */
417 if (i > mip->ra_current &&
418 map[mip->ra_index].br_blockcount >= geo->fsbcount) {
419 xfs_dir3_data_readahead(dp,
420 map[mip->ra_index].br_startoff + mip->ra_offset,
421 XFS_FSB_TO_DADDR(dp->i_mount,
422 map[mip->ra_index].br_startblock +
423 mip->ra_offset));
424 mip->ra_current = i;
425 }
426
427 /*
428 * Read-ahead a non-contiguous directory block. This doesn't
429 * use our mapping, but this is a very rare case.
430 */
431 else if (i > mip->ra_current) {
432 xfs_dir3_data_readahead(dp,
433 map[mip->ra_index].br_startoff +
434 mip->ra_offset, -1);
435 mip->ra_current = i;
436 }
437
438 /*
439 * Advance offset through the mapping table.
440 */
441 for (j = 0; j < geo->fsbcount; j += length ) {
442 /*
443 * The rest of this extent but not more than a dir
444 * block.
445 */
446 length = min_t(int, geo->fsbcount,
447 map[mip->ra_index].br_blockcount -
448 mip->ra_offset);
449 mip->ra_offset += length;
450
451 /*
452 * Advance to the next mapping if this one is used up.
453 */
454 if (mip->ra_offset == map[mip->ra_index].br_blockcount) {
455 mip->ra_offset = 0;
456 mip->ra_index++;
457 }
458 }
459 }
460 blk_finish_plug(&plug);
461
462out:
463 *bpp = bp;
464 return error;
465}
466
467/*
468 * Getdents (readdir) for leaf and node directories.
469 * This reads the data blocks only, so is the same for both forms.
470 */
471STATIC int
472xfs_dir2_leaf_getdents(
473 struct xfs_da_args *args,
474 struct dir_context *ctx,
475 size_t bufsize)
476{
477 struct xfs_inode *dp = args->dp;
478 struct xfs_buf *bp = NULL; /* data block buffer */
479 xfs_dir2_data_hdr_t *hdr; /* data block header */
480 xfs_dir2_data_entry_t *dep; /* data entry */
481 xfs_dir2_data_unused_t *dup; /* unused entry */
482 int error = 0; /* error return value */
483 int length; /* temporary length value */
484 int byteoff; /* offset in current block */
485 xfs_dir2_off_t curoff; /* current overall offset */
486 xfs_dir2_off_t newoff; /* new curoff after new blk */
487 char *ptr = NULL; /* pointer to current data */
488 struct xfs_dir2_leaf_map_info *map_info;
489 struct xfs_da_geometry *geo = args->geo;
490
491 /*
492 * If the offset is at or past the largest allowed value,
493 * give up right away.
494 */
495 if (ctx->pos >= XFS_DIR2_MAX_DATAPTR)
496 return 0;
497
498 /*
499 * Set up to bmap a number of blocks based on the caller's
500 * buffer size, the directory block size, and the filesystem
501 * block size.
502 */
503 length = howmany(bufsize + geo->blksize, (1 << geo->fsblog));
504 map_info = kmem_zalloc(offsetof(struct xfs_dir2_leaf_map_info, map) +
505 (length * sizeof(struct xfs_bmbt_irec)),
506 KM_SLEEP | KM_NOFS);
507 map_info->map_size = length;
508
509 /*
510 * Inside the loop we keep the main offset value as a byte offset
511 * in the directory file.
512 */
513 curoff = xfs_dir2_dataptr_to_byte(ctx->pos);
514
515 /*
516 * Force this conversion through db so we truncate the offset
517 * down to get the start of the data block.
518 */
519 map_info->map_off = xfs_dir2_db_to_da(geo,
520 xfs_dir2_byte_to_db(geo, curoff));
521
522 /*
523 * Loop over directory entries until we reach the end offset.
524 * Get more blocks and readahead as necessary.
525 */
526 while (curoff < XFS_DIR2_LEAF_OFFSET) {
527 __uint8_t filetype;
528
529 /*
530 * If we have no buffer, or we're off the end of the
531 * current buffer, need to get another one.
532 */
533 if (!bp || ptr >= (char *)bp->b_addr + geo->blksize) {
534 int lock_mode;
535 bool trim_map = false;
536
537 if (bp) {
538 xfs_trans_brelse(NULL, bp);
539 bp = NULL;
540 trim_map = true;
541 }
542
543 lock_mode = xfs_ilock_data_map_shared(dp);
544 error = xfs_dir2_leaf_readbuf(args, bufsize, map_info,
545 &curoff, &bp, trim_map);
546 xfs_iunlock(dp, lock_mode);
547 if (error || !map_info->map_valid)
548 break;
549
550 /*
551 * Having done a read, we need to set a new offset.
552 */
553 newoff = xfs_dir2_db_off_to_byte(geo,
554 map_info->curdb, 0);
555 /*
556 * Start of the current block.
557 */
558 if (curoff < newoff)
559 curoff = newoff;
560 /*
561 * Make sure we're in the right block.
562 */
563 else if (curoff > newoff)
564 ASSERT(xfs_dir2_byte_to_db(geo, curoff) ==
565 map_info->curdb);
566 hdr = bp->b_addr;
567 xfs_dir3_data_check(dp, bp);
568 /*
569 * Find our position in the block.
570 */
571 ptr = (char *)dp->d_ops->data_entry_p(hdr);
572 byteoff = xfs_dir2_byte_to_off(geo, curoff);
573 /*
574 * Skip past the header.
575 */
576 if (byteoff == 0)
577 curoff += dp->d_ops->data_entry_offset;
578 /*
579 * Skip past entries until we reach our offset.
580 */
581 else {
582 while ((char *)ptr - (char *)hdr < byteoff) {
583 dup = (xfs_dir2_data_unused_t *)ptr;
584
585 if (be16_to_cpu(dup->freetag)
586 == XFS_DIR2_DATA_FREE_TAG) {
587
588 length = be16_to_cpu(dup->length);
589 ptr += length;
590 continue;
591 }
592 dep = (xfs_dir2_data_entry_t *)ptr;
593 length =
594 dp->d_ops->data_entsize(dep->namelen);
595 ptr += length;
596 }
597 /*
598 * Now set our real offset.
599 */
600 curoff =
601 xfs_dir2_db_off_to_byte(geo,
602 xfs_dir2_byte_to_db(geo, curoff),
603 (char *)ptr - (char *)hdr);
604 if (ptr >= (char *)hdr + geo->blksize) {
605 continue;
606 }
607 }
608 }
609 /*
610 * We have a pointer to an entry.
611 * Is it a live one?
612 */
613 dup = (xfs_dir2_data_unused_t *)ptr;
614 /*
615 * No, it's unused, skip over it.
616 */
617 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
618 length = be16_to_cpu(dup->length);
619 ptr += length;
620 curoff += length;
621 continue;
622 }
623
624 dep = (xfs_dir2_data_entry_t *)ptr;
625 length = dp->d_ops->data_entsize(dep->namelen);
626 filetype = dp->d_ops->data_get_ftype(dep);
627
628 ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
629 if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
630 be64_to_cpu(dep->inumber),
631 xfs_dir3_get_dtype(dp->i_mount, filetype)))
632 break;
633
634 /*
635 * Advance to next entry in the block.
636 */
637 ptr += length;
638 curoff += length;
639 /* bufsize may have just been a guess; don't go negative */
640 bufsize = bufsize > length ? bufsize - length : 0;
641 }
642
643 /*
644 * All done. Set output offset value to current offset.
645 */
646 if (curoff > xfs_dir2_dataptr_to_byte(XFS_DIR2_MAX_DATAPTR))
647 ctx->pos = XFS_DIR2_MAX_DATAPTR & 0x7fffffff;
648 else
649 ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
650 kmem_free(map_info);
651 if (bp)
652 xfs_trans_brelse(NULL, bp);
653 return error;
654}
655
656/*
657 * Read a directory.
658 */
659int
660xfs_readdir(
661 struct xfs_inode *dp,
662 struct dir_context *ctx,
663 size_t bufsize)
664{
665 struct xfs_da_args args = { NULL };
666 int rval;
667 int v;
668
669 trace_xfs_readdir(dp);
670
671 if (XFS_FORCED_SHUTDOWN(dp->i_mount))
672 return -EIO;
673
674 ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
675 XFS_STATS_INC(dp->i_mount, xs_dir_getdents);
676
677 args.dp = dp;
678 args.geo = dp->i_mount->m_dir_geo;
679
680 if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
681 rval = xfs_dir2_sf_getdents(&args, ctx);
682 else if ((rval = xfs_dir2_isblock(&args, &v)))
683 ;
684 else if (v)
685 rval = xfs_dir2_block_getdents(&args, ctx);
686 else
687 rval = xfs_dir2_leaf_getdents(&args, ctx, bufsize);
688
689 return rval;
690}