1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
4 * Copyright (c) 2013 Red Hat, Inc.
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"
16 #include "xfs_dir2_priv.h"
17 #include "xfs_trace.h"
19 #include "xfs_trans.h"
20 #include "xfs_error.h"
21 #include "xfs_health.h"
24 * Directory file type support functions
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,
36 if (!xfs_has_ftype(mp))
39 if (filetype >= XFS_DIR3_FT_MAX)
42 return xfs_dir3_filetype_table[filetype];
47 struct xfs_da_args *args,
48 struct dir_context *ctx)
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;
59 struct xfs_da_geometry *geo = args->geo;
61 ASSERT(dp->i_df.if_format == XFS_DINODE_FMT_LOCAL);
62 ASSERT(dp->i_df.if_bytes == dp->i_disk_size);
66 * If the block number in the offset is out of range, we're done.
68 if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
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 "..".
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));
83 * Put . entry unless we're starting past it.
85 if (ctx->pos <= dot_offset) {
86 ctx->pos = dot_offset & 0x7fffffff;
87 if (!dir_emit(ctx, ".", 1, dp->i_ino, DT_DIR))
92 * Put .. entry unless we're starting past it.
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))
102 * Loop while there are more entries and put'ing works.
104 sfep = xfs_dir2_sf_firstentry(sfp);
105 for (i = 0; i < sfp->count; i++) {
108 off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
109 xfs_dir2_sf_get_offset(sfep));
111 if (ctx->pos > off) {
112 sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep);
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,
122 xfs_dirattr_mark_sick(dp, XFS_DATA_FORK);
123 return -EFSCORRUPTED;
125 if (!dir_emit(ctx, (char *)sfep->name, sfep->namelen, ino,
126 xfs_dir3_get_dtype(mp, filetype)))
128 sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep);
131 ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &
137 * Readdir for block directories.
140 xfs_dir2_block_getdents(
141 struct xfs_da_args *args,
142 struct dir_context *ctx,
143 unsigned int *lock_mode)
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 */
150 struct xfs_da_geometry *geo = args->geo;
151 unsigned int offset, next_offset;
155 * If the block number in the offset is out of range, we're done.
157 if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
160 error = xfs_dir3_block_read(args->trans, dp, &bp);
164 xfs_iunlock(dp, *lock_mode);
168 * Extract the byte offset we start at from the seek pointer.
169 * We'll skip entries before this.
171 wantoff = xfs_dir2_dataptr_to_off(geo, ctx->pos);
172 xfs_dir3_data_check(dp, bp);
175 * Loop over the data portion of the block.
176 * Each object is a real entry (dep) or an unused one (dup).
178 end = xfs_dir3_data_end_offset(geo, bp->b_addr);
179 for (offset = geo->data_entry_offset;
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;
189 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
190 next_offset = offset + be16_to_cpu(dup->length);
195 * Bump pointer for the next iteration.
197 next_offset = offset +
198 xfs_dir2_data_entsize(dp->i_mount, dep->namelen);
201 * The entry is before the desired starting point, skip it.
203 if (offset < wantoff)
206 cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, offset);
208 ctx->pos = cook & 0x7fffffff;
209 filetype = xfs_dir2_data_get_ftype(dp->i_mount, dep);
211 * If it didn't fit, set the final offset to here & return.
213 if (XFS_IS_CORRUPT(dp->i_mount,
214 !xfs_dir2_namecheck(dep->name,
216 xfs_dirattr_mark_sick(dp, XFS_DATA_FORK);
217 error = -EFSCORRUPTED;
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)))
227 * Reached the end of the block.
228 * Set the offset to a non-existent block 1 and return.
230 ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &
233 xfs_trans_brelse(args->trans, bp);
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.
243 xfs_dir2_leaf_readbuf(
244 struct xfs_da_args *args,
246 xfs_dir2_off_t *cur_off,
248 struct xfs_buf **bpp)
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;
260 struct xfs_iext_cursor icur;
264 error = xfs_iread_extents(args->trans, dp, XFS_DATA_FORK);
269 * Look for mapped directory blocks at or above the current offset.
270 * Truncate down to the nearest directory block to start the scanning
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))
277 if (map.br_startoff >= last_da)
279 xfs_trim_extent(&map, map_off, last_da - map_off);
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)
285 error = xfs_dir3_data_read(args->trans, dp, map.br_startoff, 0, &bp);
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).
294 ra_want = howmany(bufsize + geo->blksize, (1 << geo->fsblog));
295 if (*ra_blk >= last_da)
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)
302 if (map.br_blockcount < geo->fsbcount &&
303 !xfs_iext_next_extent(ifp, &icur, &map))
305 if (map.br_startoff >= last_da)
307 xfs_trim_extent(&map, next_ra, last_da - next_ra);
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) {
319 if (next_ra > *ra_blk) {
320 xfs_dir3_data_readahead(dp, next_ra,
321 XFS_DABUF_MAP_HOLE_OK);
324 ra_want -= geo->fsbcount;
325 next_ra += geo->fsbcount;
327 if (!xfs_iext_next_extent(ifp, &icur, &map)) {
332 blk_finish_plug(&plug);
343 * Getdents (readdir) for leaf and node directories.
344 * This reads the data blocks only, so is the same for both forms.
347 xfs_dir2_leaf_getdents(
348 struct xfs_da_args *args,
349 struct dir_context *ctx,
351 unsigned int *lock_mode)
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 */
367 * If the offset is at or past the largest allowed value,
368 * give up right away.
370 if (ctx->pos >= XFS_DIR2_MAX_DATAPTR)
374 * Inside the loop we keep the main offset value as a byte offset
375 * in the directory file.
377 curoff = xfs_dir2_dataptr_to_byte(ctx->pos);
380 * Loop over directory entries until we reach the end offset.
381 * Get more blocks and readahead as necessary.
383 while (curoff < XFS_DIR2_LEAF_OFFSET) {
387 * If we have no buffer, or we're off the end of the
388 * current buffer, need to get another one.
390 if (!bp || offset >= geo->blksize) {
392 xfs_trans_brelse(args->trans, bp);
397 *lock_mode = xfs_ilock_data_map_shared(dp);
398 error = xfs_dir2_leaf_readbuf(args, bufsize, &curoff,
403 xfs_iunlock(dp, *lock_mode);
406 xfs_dir3_data_check(dp, bp);
408 * Find our position in the block.
410 offset = geo->data_entry_offset;
411 byteoff = xfs_dir2_byte_to_off(geo, curoff);
413 * Skip past the header.
416 curoff += geo->data_entry_offset;
418 * Skip past entries until we reach our offset.
421 while (offset < byteoff) {
422 dup = bp->b_addr + offset;
424 if (be16_to_cpu(dup->freetag)
425 == XFS_DIR2_DATA_FREE_TAG) {
427 length = be16_to_cpu(dup->length);
431 dep = bp->b_addr + offset;
432 length = xfs_dir2_data_entsize(mp,
437 * Now set our real offset.
440 xfs_dir2_db_off_to_byte(geo,
441 xfs_dir2_byte_to_db(geo, curoff),
443 if (offset >= geo->blksize)
449 * We have a pointer to an entry. Is it a live one?
451 dup = bp->b_addr + offset;
454 * No, it's unused, skip over it.
456 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
457 length = be16_to_cpu(dup->length);
463 dep = bp->b_addr + offset;
464 length = xfs_dir2_data_entsize(mp, dep->namelen);
465 filetype = xfs_dir2_data_get_ftype(mp, dep);
467 ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
468 if (XFS_IS_CORRUPT(dp->i_mount,
469 !xfs_dir2_namecheck(dep->name,
471 xfs_dirattr_mark_sick(dp, XFS_DATA_FORK);
472 error = -EFSCORRUPTED;
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)))
481 * Advance to next entry in the block.
485 /* bufsize may have just been a guess; don't go negative */
486 bufsize = bufsize > length ? bufsize - length : 0;
490 * All done. Set output offset value to current offset.
492 if (curoff > xfs_dir2_dataptr_to_byte(XFS_DIR2_MAX_DATAPTR))
493 ctx->pos = XFS_DIR2_MAX_DATAPTR & 0x7fffffff;
495 ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
497 xfs_trans_brelse(args->trans, bp);
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.
511 struct xfs_trans *tp,
512 struct xfs_inode *dp,
513 struct dir_context *ctx,
516 struct xfs_da_args args = { NULL };
517 unsigned int lock_mode;
521 trace_xfs_readdir(dp);
523 if (xfs_is_shutdown(dp->i_mount))
525 if (xfs_ifork_zapped(dp, XFS_DATA_FORK))
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);
533 args.geo = dp->i_mount->m_dir_geo;
536 if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL)
537 return xfs_dir2_sf_getdents(&args, ctx);
539 lock_mode = xfs_ilock_data_map_shared(dp);
540 error = xfs_dir2_isblock(&args, &isblock);
545 error = xfs_dir2_block_getdents(&args, ctx, &lock_mode);
549 error = xfs_dir2_leaf_getdents(&args, ctx, bufsize, &lock_mode);
553 xfs_iunlock(dp, lock_mode);