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v3.15
 
  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_sb.h"
 26#include "xfs_ag.h"
 27#include "xfs_mount.h"
 28#include "xfs_da_format.h"
 29#include "xfs_da_btree.h"
 30#include "xfs_inode.h"
 31#include "xfs_dir2.h"
 32#include "xfs_dir2_priv.h"
 33#include "xfs_error.h"
 34#include "xfs_trace.h"
 35#include "xfs_bmap.h"
 36#include "xfs_trans.h"
 37#include "xfs_dinode.h"
 
 38
 39/*
 40 * Directory file type support functions
 41 */
 42static unsigned char xfs_dir3_filetype_table[] = {
 43	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK,
 44	DT_FIFO, DT_SOCK, DT_LNK, DT_WHT,
 45};
 46
 47unsigned char
 48xfs_dir3_get_dtype(
 49	struct xfs_mount	*mp,
 50	__uint8_t		filetype)
 51{
 52	if (!xfs_sb_version_hasftype(&mp->m_sb))
 53		return DT_UNKNOWN;
 54
 55	if (filetype >= XFS_DIR3_FT_MAX)
 56		return DT_UNKNOWN;
 57
 58	return xfs_dir3_filetype_table[filetype];
 59}
 60/*
 61 * @mode, if set, indicates that the type field needs to be set up.
 62 * This uses the transformation from file mode to DT_* as defined in linux/fs.h
 63 * for file type specification. This will be propagated into the directory
 64 * structure if appropriate for the given operation and filesystem config.
 65 */
 66const unsigned char xfs_mode_to_ftype[S_IFMT >> S_SHIFT] = {
 67	[0]			= XFS_DIR3_FT_UNKNOWN,
 68	[S_IFREG >> S_SHIFT]    = XFS_DIR3_FT_REG_FILE,
 69	[S_IFDIR >> S_SHIFT]    = XFS_DIR3_FT_DIR,
 70	[S_IFCHR >> S_SHIFT]    = XFS_DIR3_FT_CHRDEV,
 71	[S_IFBLK >> S_SHIFT]    = XFS_DIR3_FT_BLKDEV,
 72	[S_IFIFO >> S_SHIFT]    = XFS_DIR3_FT_FIFO,
 73	[S_IFSOCK >> S_SHIFT]   = XFS_DIR3_FT_SOCK,
 74	[S_IFLNK >> S_SHIFT]    = XFS_DIR3_FT_SYMLINK,
 75};
 76
 77STATIC int
 78xfs_dir2_sf_getdents(
 79	xfs_inode_t		*dp,		/* incore directory inode */
 80	struct dir_context	*ctx)
 81{
 82	int			i;		/* shortform entry number */
 83	xfs_mount_t		*mp;		/* filesystem mount point */
 
 84	xfs_dir2_dataptr_t	off;		/* current entry's offset */
 85	xfs_dir2_sf_entry_t	*sfep;		/* shortform directory entry */
 86	xfs_dir2_sf_hdr_t	*sfp;		/* shortform structure */
 87	xfs_dir2_dataptr_t	dot_offset;
 88	xfs_dir2_dataptr_t	dotdot_offset;
 89	xfs_ino_t		ino;
 
 90
 91	mp = dp->i_mount;
 92
 93	ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
 94	/*
 95	 * Give up if the directory is way too short.
 96	 */
 97	if (dp->i_d.di_size < offsetof(xfs_dir2_sf_hdr_t, parent)) {
 98		ASSERT(XFS_FORCED_SHUTDOWN(mp));
 99		return XFS_ERROR(EIO);
100	}
101
102	ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
103	ASSERT(dp->i_df.if_u1.if_data != NULL);
104
105	sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
106
107	ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(sfp->i8count));
108
109	/*
110	 * If the block number in the offset is out of range, we're done.
111	 */
112	if (xfs_dir2_dataptr_to_db(mp, ctx->pos) > mp->m_dirdatablk)
113		return 0;
114
115	/*
116	 * Precalculate offsets for . and .. as we will always need them.
117	 *
118	 * XXX(hch): the second argument is sometimes 0 and sometimes
119	 * mp->m_dirdatablk.
120	 */
121	dot_offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
122						dp->d_ops->data_dot_offset);
123	dotdot_offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
124						dp->d_ops->data_dotdot_offset);
125
126	/*
127	 * Put . entry unless we're starting past it.
128	 */
129	if (ctx->pos <= dot_offset) {
130		ctx->pos = dot_offset & 0x7fffffff;
131		if (!dir_emit(ctx, ".", 1, dp->i_ino, DT_DIR))
132			return 0;
133	}
134
135	/*
136	 * Put .. entry unless we're starting past it.
137	 */
138	if (ctx->pos <= dotdot_offset) {
139		ino = dp->d_ops->sf_get_parent_ino(sfp);
140		ctx->pos = dotdot_offset & 0x7fffffff;
141		if (!dir_emit(ctx, "..", 2, ino, DT_DIR))
142			return 0;
143	}
144
145	/*
146	 * Loop while there are more entries and put'ing works.
147	 */
148	sfep = xfs_dir2_sf_firstentry(sfp);
149	for (i = 0; i < sfp->count; i++) {
150		__uint8_t filetype;
151
152		off = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
153				xfs_dir2_sf_get_offset(sfep));
154
155		if (ctx->pos > off) {
156			sfep = dp->d_ops->sf_nextentry(sfp, sfep);
157			continue;
158		}
159
160		ino = dp->d_ops->sf_get_ino(sfp, sfep);
161		filetype = dp->d_ops->sf_get_ftype(sfep);
162		ctx->pos = off & 0x7fffffff;
 
 
 
 
 
 
163		if (!dir_emit(ctx, (char *)sfep->name, sfep->namelen, ino,
164			    xfs_dir3_get_dtype(mp, filetype)))
165			return 0;
166		sfep = dp->d_ops->sf_nextentry(sfp, sfep);
167	}
168
169	ctx->pos = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0) &
170			0x7fffffff;
171	return 0;
172}
173
174/*
175 * Readdir for block directories.
176 */
177STATIC int
178xfs_dir2_block_getdents(
179	xfs_inode_t		*dp,		/* incore inode */
180	struct dir_context	*ctx)
 
181{
182	xfs_dir2_data_hdr_t	*hdr;		/* block header */
183	struct xfs_buf		*bp;		/* buffer for block */
184	xfs_dir2_block_tail_t	*btp;		/* block tail */
185	xfs_dir2_data_entry_t	*dep;		/* block data entry */
186	xfs_dir2_data_unused_t	*dup;		/* block unused entry */
187	char			*endptr;	/* end of the data entries */
188	int			error;		/* error return value */
189	xfs_mount_t		*mp;		/* filesystem mount point */
190	char			*ptr;		/* current data entry */
191	int			wantoff;	/* starting block offset */
192	xfs_off_t		cook;
 
 
 
193
194	mp = dp->i_mount;
195	/*
196	 * If the block number in the offset is out of range, we're done.
197	 */
198	if (xfs_dir2_dataptr_to_db(mp, ctx->pos) > mp->m_dirdatablk)
199		return 0;
200
201	error = xfs_dir3_block_read(NULL, dp, &bp);
202	if (error)
203		return error;
204
 
 
 
205	/*
206	 * Extract the byte offset we start at from the seek pointer.
207	 * We'll skip entries before this.
208	 */
209	wantoff = xfs_dir2_dataptr_to_off(mp, ctx->pos);
210	hdr = bp->b_addr;
211	xfs_dir3_data_check(dp, bp);
212	/*
213	 * Set up values for the loop.
214	 */
215	btp = xfs_dir2_block_tail_p(mp, hdr);
216	ptr = (char *)dp->d_ops->data_entry_p(hdr);
217	endptr = (char *)xfs_dir2_block_leaf_p(btp);
218
219	/*
220	 * Loop over the data portion of the block.
221	 * Each object is a real entry (dep) or an unused one (dup).
222	 */
223	while (ptr < endptr) {
224		__uint8_t filetype;
 
 
 
 
 
225
226		dup = (xfs_dir2_data_unused_t *)ptr;
227		/*
228		 * Unused, skip it.
229		 */
230		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
231			ptr += be16_to_cpu(dup->length);
232			continue;
233		}
234
235		dep = (xfs_dir2_data_entry_t *)ptr;
236
237		/*
238		 * Bump pointer for the next iteration.
239		 */
240		ptr += dp->d_ops->data_entsize(dep->namelen);
 
 
241		/*
242		 * The entry is before the desired starting point, skip it.
243		 */
244		if ((char *)dep - (char *)hdr < wantoff)
245			continue;
246
247		cook = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
248					    (char *)dep - (char *)hdr);
249
250		ctx->pos = cook & 0x7fffffff;
251		filetype = dp->d_ops->data_get_ftype(dep);
252		/*
253		 * If it didn't fit, set the final offset to here & return.
254		 */
 
 
 
 
 
 
 
255		if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
256			    be64_to_cpu(dep->inumber),
257			    xfs_dir3_get_dtype(mp, filetype))) {
258			xfs_trans_brelse(NULL, bp);
259			return 0;
260		}
261	}
262
263	/*
264	 * Reached the end of the block.
265	 * Set the offset to a non-existent block 1 and return.
266	 */
267	ctx->pos = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0) &
268			0x7fffffff;
269	xfs_trans_brelse(NULL, bp);
270	return 0;
 
271}
272
273struct xfs_dir2_leaf_map_info {
274	xfs_extlen_t	map_blocks;	/* number of fsbs in map */
275	xfs_dablk_t	map_off;	/* last mapped file offset */
276	int		map_size;	/* total entries in *map */
277	int		map_valid;	/* valid entries in *map */
278	int		nmap;		/* mappings to ask xfs_bmapi */
279	xfs_dir2_db_t	curdb;		/* db for current block */
280	int		ra_current;	/* number of read-ahead blks */
281	int		ra_index;	/* *map index for read-ahead */
282	int		ra_offset;	/* map entry offset for ra */
283	int		ra_want;	/* readahead count wanted */
284	struct xfs_bmbt_irec map[];	/* map vector for blocks */
285};
286
287STATIC int
288xfs_dir2_leaf_readbuf(
289	struct xfs_inode	*dp,
290	size_t			bufsize,
291	struct xfs_dir2_leaf_map_info *mip,
292	xfs_dir2_off_t		*curoff,
293	struct xfs_buf		**bpp)
294{
295	struct xfs_mount	*mp = dp->i_mount;
296	struct xfs_buf		*bp = *bpp;
297	struct xfs_bmbt_irec	*map = mip->map;
 
 
298	struct blk_plug		plug;
 
 
 
 
 
 
299	int			error = 0;
300	int			length;
301	int			i;
302	int			j;
303
304	/*
305	 * If we have a buffer, we need to release it and
306	 * take it out of the mapping.
307	 */
308
309	if (bp) {
310		xfs_trans_brelse(NULL, bp);
311		bp = NULL;
312		mip->map_blocks -= mp->m_dirblkfsbs;
313		/*
314		 * Loop to get rid of the extents for the
315		 * directory block.
316		 */
317		for (i = mp->m_dirblkfsbs; i > 0; ) {
318			j = min_t(int, map->br_blockcount, i);
319			map->br_blockcount -= j;
320			map->br_startblock += j;
321			map->br_startoff += j;
322			/*
323			 * If mapping is done, pitch it from
324			 * the table.
325			 */
326			if (!map->br_blockcount && --mip->map_valid)
327				memmove(&map[0], &map[1],
328					sizeof(map[0]) * mip->map_valid);
329			i -= j;
330		}
331	}
332
333	/*
334	 * Recalculate the readahead blocks wanted.
335	 */
336	mip->ra_want = howmany(bufsize + mp->m_dirblksize,
337			       mp->m_sb.sb_blocksize) - 1;
338	ASSERT(mip->ra_want >= 0);
339
340	/*
341	 * If we don't have as many as we want, and we haven't
342	 * run out of data blocks, get some more mappings.
343	 */
344	if (1 + mip->ra_want > mip->map_blocks &&
345	    mip->map_off < xfs_dir2_byte_to_da(mp, XFS_DIR2_LEAF_OFFSET)) {
346		/*
347		 * Get more bmaps, fill in after the ones
348		 * we already have in the table.
349		 */
350		mip->nmap = mip->map_size - mip->map_valid;
351		error = xfs_bmapi_read(dp, mip->map_off,
352				xfs_dir2_byte_to_da(mp, XFS_DIR2_LEAF_OFFSET) -
353								mip->map_off,
354				&map[mip->map_valid], &mip->nmap, 0);
355
356		/*
357		 * Don't know if we should ignore this or try to return an
358		 * error.  The trouble with returning errors is that readdir
359		 * will just stop without actually passing the error through.
360		 */
361		if (error)
362			goto out;	/* XXX */
363
364		/*
365		 * If we got all the mappings we asked for, set the final map
366		 * offset based on the last bmap value received.  Otherwise,
367		 * we've reached the end.
368		 */
369		if (mip->nmap == mip->map_size - mip->map_valid) {
370			i = mip->map_valid + mip->nmap - 1;
371			mip->map_off = map[i].br_startoff + map[i].br_blockcount;
372		} else
373			mip->map_off = xfs_dir2_byte_to_da(mp,
374							XFS_DIR2_LEAF_OFFSET);
375
376		/*
377		 * Look for holes in the mapping, and eliminate them.  Count up
378		 * the valid blocks.
379		 */
380		for (i = mip->map_valid; i < mip->map_valid + mip->nmap; ) {
381			if (map[i].br_startblock == HOLESTARTBLOCK) {
382				mip->nmap--;
383				length = mip->map_valid + mip->nmap - i;
384				if (length)
385					memmove(&map[i], &map[i + 1],
386						sizeof(map[i]) * length);
387			} else {
388				mip->map_blocks += map[i].br_blockcount;
389				i++;
390			}
391		}
392		mip->map_valid += mip->nmap;
393	}
394
395	/*
396	 * No valid mappings, so no more data blocks.
397	 */
398	if (!mip->map_valid) {
399		*curoff = xfs_dir2_da_to_byte(mp, mip->map_off);
400		goto out;
401	}
402
403	/*
404	 * Read the directory block starting at the first mapping.
405	 */
406	mip->curdb = xfs_dir2_da_to_db(mp, map->br_startoff);
407	error = xfs_dir3_data_read(NULL, dp, map->br_startoff,
408			map->br_blockcount >= mp->m_dirblkfsbs ?
409			    XFS_FSB_TO_DADDR(mp, map->br_startblock) : -1, &bp);
 
 
 
 
 
410
411	/*
412	 * Should just skip over the data block instead of giving up.
413	 */
 
 
 
414	if (error)
415		goto out;	/* XXX */
416
417	/*
418	 * Adjust the current amount of read-ahead: we just read a block that
419	 * was previously ra.
 
420	 */
421	if (mip->ra_current)
422		mip->ra_current -= mp->m_dirblkfsbs;
 
 
 
 
 
 
 
 
 
 
 
 
423
424	/*
425	 * Do we need more readahead?
426	 */
427	blk_start_plug(&plug);
428	for (mip->ra_index = mip->ra_offset = i = 0;
429	     mip->ra_want > mip->ra_current && i < mip->map_blocks;
430	     i += mp->m_dirblkfsbs) {
431		ASSERT(mip->ra_index < mip->map_valid);
432		/*
433		 * Read-ahead a contiguous directory block.
434		 */
435		if (i > mip->ra_current &&
436		    map[mip->ra_index].br_blockcount >= mp->m_dirblkfsbs) {
437			xfs_dir3_data_readahead(NULL, dp,
438				map[mip->ra_index].br_startoff + mip->ra_offset,
439				XFS_FSB_TO_DADDR(mp,
440					map[mip->ra_index].br_startblock +
441							mip->ra_offset));
442			mip->ra_current = i;
443		}
444
445		/*
446		 * Read-ahead a non-contiguous directory block.  This doesn't
447		 * use our mapping, but this is a very rare case.
448		 */
449		else if (i > mip->ra_current) {
450			xfs_dir3_data_readahead(NULL, dp,
451					map[mip->ra_index].br_startoff +
452							mip->ra_offset, -1);
453			mip->ra_current = i;
454		}
455
456		/*
457		 * Advance offset through the mapping table.
458		 */
459		for (j = 0; j < mp->m_dirblkfsbs; j++) {
460			/*
461			 * The rest of this extent but not more than a dir
462			 * block.
463			 */
464			length = min_t(int, mp->m_dirblkfsbs,
465					map[mip->ra_index].br_blockcount -
466							mip->ra_offset);
467			j += length;
468			mip->ra_offset += length;
469
470			/*
471			 * Advance to the next mapping if this one is used up.
472			 */
473			if (mip->ra_offset == map[mip->ra_index].br_blockcount) {
474				mip->ra_offset = 0;
475				mip->ra_index++;
476			}
 
 
 
 
 
 
477		}
478	}
479	blk_finish_plug(&plug);
480
481out:
482	*bpp = bp;
483	return error;
 
 
 
484}
485
486/*
487 * Getdents (readdir) for leaf and node directories.
488 * This reads the data blocks only, so is the same for both forms.
489 */
490STATIC int
491xfs_dir2_leaf_getdents(
492	xfs_inode_t		*dp,		/* incore directory inode */
493	struct dir_context	*ctx,
494	size_t			bufsize)
 
495{
 
 
496	struct xfs_buf		*bp = NULL;	/* data block buffer */
497	xfs_dir2_data_hdr_t	*hdr;		/* data block header */
498	xfs_dir2_data_entry_t	*dep;		/* data entry */
499	xfs_dir2_data_unused_t	*dup;		/* unused entry */
500	int			error = 0;	/* error return value */
 
 
501	int			length;		/* temporary length value */
502	xfs_mount_t		*mp;		/* filesystem mount point */
503	int			byteoff;	/* offset in current block */
504	xfs_dir2_off_t		curoff;		/* current overall offset */
505	xfs_dir2_off_t		newoff;		/* new curoff after new blk */
506	char			*ptr = NULL;	/* pointer to current data */
507	struct xfs_dir2_leaf_map_info *map_info;
508
509	/*
510	 * If the offset is at or past the largest allowed value,
511	 * give up right away.
512	 */
513	if (ctx->pos >= XFS_DIR2_MAX_DATAPTR)
514		return 0;
515
516	mp = dp->i_mount;
517
518	/*
519	 * Set up to bmap a number of blocks based on the caller's
520	 * buffer size, the directory block size, and the filesystem
521	 * block size.
522	 */
523	length = howmany(bufsize + mp->m_dirblksize,
524				     mp->m_sb.sb_blocksize);
525	map_info = kmem_zalloc(offsetof(struct xfs_dir2_leaf_map_info, map) +
526				(length * sizeof(struct xfs_bmbt_irec)),
527			       KM_SLEEP | KM_NOFS);
528	map_info->map_size = length;
529
530	/*
531	 * Inside the loop we keep the main offset value as a byte offset
532	 * in the directory file.
533	 */
534	curoff = xfs_dir2_dataptr_to_byte(mp, ctx->pos);
535
536	/*
537	 * Force this conversion through db so we truncate the offset
538	 * down to get the start of the data block.
539	 */
540	map_info->map_off = xfs_dir2_db_to_da(mp,
541					      xfs_dir2_byte_to_db(mp, curoff));
542
543	/*
544	 * Loop over directory entries until we reach the end offset.
545	 * Get more blocks and readahead as necessary.
546	 */
547	while (curoff < XFS_DIR2_LEAF_OFFSET) {
548		__uint8_t filetype;
549
550		/*
551		 * If we have no buffer, or we're off the end of the
552		 * current buffer, need to get another one.
553		 */
554		if (!bp || ptr >= (char *)bp->b_addr + mp->m_dirblksize) {
 
 
 
 
555
556			error = xfs_dir2_leaf_readbuf(dp, bufsize, map_info,
557						      &curoff, &bp);
558			if (error || !map_info->map_valid)
 
 
559				break;
560
561			/*
562			 * Having done a read, we need to set a new offset.
563			 */
564			newoff = xfs_dir2_db_off_to_byte(mp, map_info->curdb, 0);
565			/*
566			 * Start of the current block.
567			 */
568			if (curoff < newoff)
569				curoff = newoff;
570			/*
571			 * Make sure we're in the right block.
572			 */
573			else if (curoff > newoff)
574				ASSERT(xfs_dir2_byte_to_db(mp, curoff) ==
575				       map_info->curdb);
576			hdr = bp->b_addr;
577			xfs_dir3_data_check(dp, bp);
578			/*
579			 * Find our position in the block.
580			 */
581			ptr = (char *)dp->d_ops->data_entry_p(hdr);
582			byteoff = xfs_dir2_byte_to_off(mp, curoff);
583			/*
584			 * Skip past the header.
585			 */
586			if (byteoff == 0)
587				curoff += dp->d_ops->data_entry_offset;
588			/*
589			 * Skip past entries until we reach our offset.
590			 */
591			else {
592				while ((char *)ptr - (char *)hdr < byteoff) {
593					dup = (xfs_dir2_data_unused_t *)ptr;
594
595					if (be16_to_cpu(dup->freetag)
596						  == XFS_DIR2_DATA_FREE_TAG) {
597
598						length = be16_to_cpu(dup->length);
599						ptr += length;
600						continue;
601					}
602					dep = (xfs_dir2_data_entry_t *)ptr;
603					length =
604					   dp->d_ops->data_entsize(dep->namelen);
605					ptr += length;
606				}
607				/*
608				 * Now set our real offset.
609				 */
610				curoff =
611					xfs_dir2_db_off_to_byte(mp,
612					    xfs_dir2_byte_to_db(mp, curoff),
613					    (char *)ptr - (char *)hdr);
614				if (ptr >= (char *)hdr + mp->m_dirblksize) {
615					continue;
616				}
617			}
618		}
 
619		/*
620		 * We have a pointer to an entry.
621		 * Is it a live one?
622		 */
623		dup = (xfs_dir2_data_unused_t *)ptr;
 
624		/*
625		 * No, it's unused, skip over it.
626		 */
627		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
628			length = be16_to_cpu(dup->length);
629			ptr += length;
630			curoff += length;
631			continue;
632		}
633
634		dep = (xfs_dir2_data_entry_t *)ptr;
635		length = dp->d_ops->data_entsize(dep->namelen);
636		filetype = dp->d_ops->data_get_ftype(dep);
637
638		ctx->pos = xfs_dir2_byte_to_dataptr(mp, curoff) & 0x7fffffff;
 
 
 
 
 
 
 
639		if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
640			    be64_to_cpu(dep->inumber),
641			    xfs_dir3_get_dtype(mp, filetype)))
642			break;
643
644		/*
645		 * Advance to next entry in the block.
646		 */
647		ptr += length;
648		curoff += length;
649		/* bufsize may have just been a guess; don't go negative */
650		bufsize = bufsize > length ? bufsize - length : 0;
651	}
652
653	/*
654	 * All done.  Set output offset value to current offset.
655	 */
656	if (curoff > xfs_dir2_dataptr_to_byte(mp, XFS_DIR2_MAX_DATAPTR))
657		ctx->pos = XFS_DIR2_MAX_DATAPTR & 0x7fffffff;
658	else
659		ctx->pos = xfs_dir2_byte_to_dataptr(mp, curoff) & 0x7fffffff;
660	kmem_free(map_info);
661	if (bp)
662		xfs_trans_brelse(NULL, bp);
663	return error;
664}
665
666/*
667 * Read a directory.
 
 
 
 
 
668 */
669int
670xfs_readdir(
671	xfs_inode_t	*dp,
672	struct dir_context *ctx,
673	size_t		bufsize)
 
674{
675	int		rval;		/* return value */
676	int		v;		/* type-checking value */
677	uint		lock_mode;
678
679	trace_xfs_readdir(dp);
680
681	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
682		return XFS_ERROR(EIO);
 
 
 
 
 
 
 
 
 
 
 
683
684	ASSERT(S_ISDIR(dp->i_d.di_mode));
685	XFS_STATS_INC(xs_dir_getdents);
686
687	lock_mode = xfs_ilock_data_map_shared(dp);
688	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
689		rval = xfs_dir2_sf_getdents(dp, ctx);
690	else if ((rval = xfs_dir2_isblock(NULL, dp, &v)))
691		;
692	else if (v)
693		rval = xfs_dir2_block_getdents(dp, ctx);
694	else
695		rval = xfs_dir2_leaf_getdents(dp, ctx, bufsize);
696	xfs_iunlock(dp, lock_mode);
 
 
697
698	return rval;
 
 
699}
v6.13.7
  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}