xref: /linux/fs/xfs/libxfs/xfs_dir2_data.c (revision b85d45947951d23cb22d90caecf4c1eb81342c96)
1 /*
2  * Copyright (c) 2000-2002,2005 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_mount.h"
25 #include "xfs_da_format.h"
26 #include "xfs_da_btree.h"
27 #include "xfs_inode.h"
28 #include "xfs_dir2.h"
29 #include "xfs_dir2_priv.h"
30 #include "xfs_error.h"
31 #include "xfs_trans.h"
32 #include "xfs_buf_item.h"
33 #include "xfs_cksum.h"
34 
35 /*
36  * Check the consistency of the data block.
37  * The input can also be a block-format directory.
38  * Return 0 is the buffer is good, otherwise an error.
39  */
40 int
41 __xfs_dir3_data_check(
42 	struct xfs_inode	*dp,		/* incore inode pointer */
43 	struct xfs_buf		*bp)		/* data block's buffer */
44 {
45 	xfs_dir2_dataptr_t	addr;		/* addr for leaf lookup */
46 	xfs_dir2_data_free_t	*bf;		/* bestfree table */
47 	xfs_dir2_block_tail_t	*btp=NULL;	/* block tail */
48 	int			count;		/* count of entries found */
49 	xfs_dir2_data_hdr_t	*hdr;		/* data block header */
50 	xfs_dir2_data_entry_t	*dep;		/* data entry */
51 	xfs_dir2_data_free_t	*dfp;		/* bestfree entry */
52 	xfs_dir2_data_unused_t	*dup;		/* unused entry */
53 	char			*endp;		/* end of useful data */
54 	int			freeseen;	/* mask of bestfrees seen */
55 	xfs_dahash_t		hash;		/* hash of current name */
56 	int			i;		/* leaf index */
57 	int			lastfree;	/* last entry was unused */
58 	xfs_dir2_leaf_entry_t	*lep=NULL;	/* block leaf entries */
59 	xfs_mount_t		*mp;		/* filesystem mount point */
60 	char			*p;		/* current data position */
61 	int			stale;		/* count of stale leaves */
62 	struct xfs_name		name;
63 	const struct xfs_dir_ops *ops;
64 	struct xfs_da_geometry	*geo;
65 
66 	mp = bp->b_target->bt_mount;
67 	geo = mp->m_dir_geo;
68 
69 	/*
70 	 * We can be passed a null dp here from a verifier, so we need to go the
71 	 * hard way to get them.
72 	 */
73 	ops = xfs_dir_get_ops(mp, dp);
74 
75 	hdr = bp->b_addr;
76 	p = (char *)ops->data_entry_p(hdr);
77 
78 	switch (hdr->magic) {
79 	case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
80 	case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
81 		btp = xfs_dir2_block_tail_p(geo, hdr);
82 		lep = xfs_dir2_block_leaf_p(btp);
83 		endp = (char *)lep;
84 
85 		/*
86 		 * The number of leaf entries is limited by the size of the
87 		 * block and the amount of space used by the data entries.
88 		 * We don't know how much space is used by the data entries yet,
89 		 * so just ensure that the count falls somewhere inside the
90 		 * block right now.
91 		 */
92 		XFS_WANT_CORRUPTED_RETURN(mp, be32_to_cpu(btp->count) <
93 			((char *)btp - p) / sizeof(struct xfs_dir2_leaf_entry));
94 		break;
95 	case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
96 	case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
97 		endp = (char *)hdr + geo->blksize;
98 		break;
99 	default:
100 		XFS_ERROR_REPORT("Bad Magic", XFS_ERRLEVEL_LOW, mp);
101 		return -EFSCORRUPTED;
102 	}
103 
104 	/*
105 	 * Account for zero bestfree entries.
106 	 */
107 	bf = ops->data_bestfree_p(hdr);
108 	count = lastfree = freeseen = 0;
109 	if (!bf[0].length) {
110 		XFS_WANT_CORRUPTED_RETURN(mp, !bf[0].offset);
111 		freeseen |= 1 << 0;
112 	}
113 	if (!bf[1].length) {
114 		XFS_WANT_CORRUPTED_RETURN(mp, !bf[1].offset);
115 		freeseen |= 1 << 1;
116 	}
117 	if (!bf[2].length) {
118 		XFS_WANT_CORRUPTED_RETURN(mp, !bf[2].offset);
119 		freeseen |= 1 << 2;
120 	}
121 
122 	XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[0].length) >=
123 						be16_to_cpu(bf[1].length));
124 	XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[1].length) >=
125 						be16_to_cpu(bf[2].length));
126 	/*
127 	 * Loop over the data/unused entries.
128 	 */
129 	while (p < endp) {
130 		dup = (xfs_dir2_data_unused_t *)p;
131 		/*
132 		 * If it's unused, look for the space in the bestfree table.
133 		 * If we find it, account for that, else make sure it
134 		 * doesn't need to be there.
135 		 */
136 		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
137 			XFS_WANT_CORRUPTED_RETURN(mp, lastfree == 0);
138 			XFS_WANT_CORRUPTED_RETURN(mp,
139 				be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
140 					       (char *)dup - (char *)hdr);
141 			dfp = xfs_dir2_data_freefind(hdr, bf, dup);
142 			if (dfp) {
143 				i = (int)(dfp - bf);
144 				XFS_WANT_CORRUPTED_RETURN(mp,
145 					(freeseen & (1 << i)) == 0);
146 				freeseen |= 1 << i;
147 			} else {
148 				XFS_WANT_CORRUPTED_RETURN(mp,
149 					be16_to_cpu(dup->length) <=
150 						be16_to_cpu(bf[2].length));
151 			}
152 			p += be16_to_cpu(dup->length);
153 			lastfree = 1;
154 			continue;
155 		}
156 		/*
157 		 * It's a real entry.  Validate the fields.
158 		 * If this is a block directory then make sure it's
159 		 * in the leaf section of the block.
160 		 * The linear search is crude but this is DEBUG code.
161 		 */
162 		dep = (xfs_dir2_data_entry_t *)p;
163 		XFS_WANT_CORRUPTED_RETURN(mp, dep->namelen != 0);
164 		XFS_WANT_CORRUPTED_RETURN(mp,
165 			!xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)));
166 		XFS_WANT_CORRUPTED_RETURN(mp,
167 			be16_to_cpu(*ops->data_entry_tag_p(dep)) ==
168 					       (char *)dep - (char *)hdr);
169 		XFS_WANT_CORRUPTED_RETURN(mp,
170 				ops->data_get_ftype(dep) < XFS_DIR3_FT_MAX);
171 		count++;
172 		lastfree = 0;
173 		if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
174 		    hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
175 			addr = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
176 						(xfs_dir2_data_aoff_t)
177 						((char *)dep - (char *)hdr));
178 			name.name = dep->name;
179 			name.len = dep->namelen;
180 			hash = mp->m_dirnameops->hashname(&name);
181 			for (i = 0; i < be32_to_cpu(btp->count); i++) {
182 				if (be32_to_cpu(lep[i].address) == addr &&
183 				    be32_to_cpu(lep[i].hashval) == hash)
184 					break;
185 			}
186 			XFS_WANT_CORRUPTED_RETURN(mp,
187 						  i < be32_to_cpu(btp->count));
188 		}
189 		p += ops->data_entsize(dep->namelen);
190 	}
191 	/*
192 	 * Need to have seen all the entries and all the bestfree slots.
193 	 */
194 	XFS_WANT_CORRUPTED_RETURN(mp, freeseen == 7);
195 	if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
196 	    hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
197 		for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
198 			if (lep[i].address ==
199 			    cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
200 				stale++;
201 			if (i > 0)
202 				XFS_WANT_CORRUPTED_RETURN(mp,
203 					be32_to_cpu(lep[i].hashval) >=
204 						be32_to_cpu(lep[i - 1].hashval));
205 		}
206 		XFS_WANT_CORRUPTED_RETURN(mp, count ==
207 			be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
208 		XFS_WANT_CORRUPTED_RETURN(mp, stale == be32_to_cpu(btp->stale));
209 	}
210 	return 0;
211 }
212 
213 static bool
214 xfs_dir3_data_verify(
215 	struct xfs_buf		*bp)
216 {
217 	struct xfs_mount	*mp = bp->b_target->bt_mount;
218 	struct xfs_dir3_blk_hdr	*hdr3 = bp->b_addr;
219 
220 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
221 		if (hdr3->magic != cpu_to_be32(XFS_DIR3_DATA_MAGIC))
222 			return false;
223 		if (!uuid_equal(&hdr3->uuid, &mp->m_sb.sb_meta_uuid))
224 			return false;
225 		if (be64_to_cpu(hdr3->blkno) != bp->b_bn)
226 			return false;
227 	} else {
228 		if (hdr3->magic != cpu_to_be32(XFS_DIR2_DATA_MAGIC))
229 			return false;
230 	}
231 	if (__xfs_dir3_data_check(NULL, bp))
232 		return false;
233 	return true;
234 }
235 
236 /*
237  * Readahead of the first block of the directory when it is opened is completely
238  * oblivious to the format of the directory. Hence we can either get a block
239  * format buffer or a data format buffer on readahead.
240  */
241 static void
242 xfs_dir3_data_reada_verify(
243 	struct xfs_buf		*bp)
244 {
245 	struct xfs_dir2_data_hdr *hdr = bp->b_addr;
246 
247 	switch (hdr->magic) {
248 	case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
249 	case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
250 		bp->b_ops = &xfs_dir3_block_buf_ops;
251 		bp->b_ops->verify_read(bp);
252 		return;
253 	case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
254 	case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
255 		bp->b_ops = &xfs_dir3_data_buf_ops;
256 		bp->b_ops->verify_read(bp);
257 		return;
258 	default:
259 		xfs_buf_ioerror(bp, -EFSCORRUPTED);
260 		xfs_verifier_error(bp);
261 		break;
262 	}
263 }
264 
265 static void
266 xfs_dir3_data_read_verify(
267 	struct xfs_buf	*bp)
268 {
269 	struct xfs_mount	*mp = bp->b_target->bt_mount;
270 
271 	if (xfs_sb_version_hascrc(&mp->m_sb) &&
272 	     !xfs_buf_verify_cksum(bp, XFS_DIR3_DATA_CRC_OFF))
273 		 xfs_buf_ioerror(bp, -EFSBADCRC);
274 	else if (!xfs_dir3_data_verify(bp))
275 		xfs_buf_ioerror(bp, -EFSCORRUPTED);
276 
277 	if (bp->b_error)
278 		xfs_verifier_error(bp);
279 }
280 
281 static void
282 xfs_dir3_data_write_verify(
283 	struct xfs_buf	*bp)
284 {
285 	struct xfs_mount	*mp = bp->b_target->bt_mount;
286 	struct xfs_buf_log_item	*bip = bp->b_fspriv;
287 	struct xfs_dir3_blk_hdr	*hdr3 = bp->b_addr;
288 
289 	if (!xfs_dir3_data_verify(bp)) {
290 		xfs_buf_ioerror(bp, -EFSCORRUPTED);
291 		xfs_verifier_error(bp);
292 		return;
293 	}
294 
295 	if (!xfs_sb_version_hascrc(&mp->m_sb))
296 		return;
297 
298 	if (bip)
299 		hdr3->lsn = cpu_to_be64(bip->bli_item.li_lsn);
300 
301 	xfs_buf_update_cksum(bp, XFS_DIR3_DATA_CRC_OFF);
302 }
303 
304 const struct xfs_buf_ops xfs_dir3_data_buf_ops = {
305 	.verify_read = xfs_dir3_data_read_verify,
306 	.verify_write = xfs_dir3_data_write_verify,
307 };
308 
309 static const struct xfs_buf_ops xfs_dir3_data_reada_buf_ops = {
310 	.verify_read = xfs_dir3_data_reada_verify,
311 	.verify_write = xfs_dir3_data_write_verify,
312 };
313 
314 
315 int
316 xfs_dir3_data_read(
317 	struct xfs_trans	*tp,
318 	struct xfs_inode	*dp,
319 	xfs_dablk_t		bno,
320 	xfs_daddr_t		mapped_bno,
321 	struct xfs_buf		**bpp)
322 {
323 	int			err;
324 
325 	err = xfs_da_read_buf(tp, dp, bno, mapped_bno, bpp,
326 				XFS_DATA_FORK, &xfs_dir3_data_buf_ops);
327 	if (!err && tp)
328 		xfs_trans_buf_set_type(tp, *bpp, XFS_BLFT_DIR_DATA_BUF);
329 	return err;
330 }
331 
332 int
333 xfs_dir3_data_readahead(
334 	struct xfs_inode	*dp,
335 	xfs_dablk_t		bno,
336 	xfs_daddr_t		mapped_bno)
337 {
338 	return xfs_da_reada_buf(dp, bno, mapped_bno,
339 				XFS_DATA_FORK, &xfs_dir3_data_reada_buf_ops);
340 }
341 
342 /*
343  * Given a data block and an unused entry from that block,
344  * return the bestfree entry if any that corresponds to it.
345  */
346 xfs_dir2_data_free_t *
347 xfs_dir2_data_freefind(
348 	struct xfs_dir2_data_hdr *hdr,		/* data block header */
349 	struct xfs_dir2_data_free *bf,		/* bestfree table pointer */
350 	struct xfs_dir2_data_unused *dup)	/* unused space */
351 {
352 	xfs_dir2_data_free_t	*dfp;		/* bestfree entry */
353 	xfs_dir2_data_aoff_t	off;		/* offset value needed */
354 #ifdef DEBUG
355 	int			matched;	/* matched the value */
356 	int			seenzero;	/* saw a 0 bestfree entry */
357 #endif
358 
359 	off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
360 
361 #ifdef DEBUG
362 	/*
363 	 * Validate some consistency in the bestfree table.
364 	 * Check order, non-overlapping entries, and if we find the
365 	 * one we're looking for it has to be exact.
366 	 */
367 	ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
368 	       hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
369 	       hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
370 	       hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
371 	for (dfp = &bf[0], seenzero = matched = 0;
372 	     dfp < &bf[XFS_DIR2_DATA_FD_COUNT];
373 	     dfp++) {
374 		if (!dfp->offset) {
375 			ASSERT(!dfp->length);
376 			seenzero = 1;
377 			continue;
378 		}
379 		ASSERT(seenzero == 0);
380 		if (be16_to_cpu(dfp->offset) == off) {
381 			matched = 1;
382 			ASSERT(dfp->length == dup->length);
383 		} else if (off < be16_to_cpu(dfp->offset))
384 			ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
385 		else
386 			ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
387 		ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
388 		if (dfp > &bf[0])
389 			ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
390 	}
391 #endif
392 	/*
393 	 * If this is smaller than the smallest bestfree entry,
394 	 * it can't be there since they're sorted.
395 	 */
396 	if (be16_to_cpu(dup->length) <
397 	    be16_to_cpu(bf[XFS_DIR2_DATA_FD_COUNT - 1].length))
398 		return NULL;
399 	/*
400 	 * Look at the three bestfree entries for our guy.
401 	 */
402 	for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
403 		if (!dfp->offset)
404 			return NULL;
405 		if (be16_to_cpu(dfp->offset) == off)
406 			return dfp;
407 	}
408 	/*
409 	 * Didn't find it.  This only happens if there are duplicate lengths.
410 	 */
411 	return NULL;
412 }
413 
414 /*
415  * Insert an unused-space entry into the bestfree table.
416  */
417 xfs_dir2_data_free_t *				/* entry inserted */
418 xfs_dir2_data_freeinsert(
419 	struct xfs_dir2_data_hdr *hdr,		/* data block pointer */
420 	struct xfs_dir2_data_free *dfp,		/* bestfree table pointer */
421 	struct xfs_dir2_data_unused *dup,	/* unused space */
422 	int			*loghead)	/* log the data header (out) */
423 {
424 	xfs_dir2_data_free_t	new;		/* new bestfree entry */
425 
426 	ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
427 	       hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
428 	       hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
429 	       hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
430 
431 	new.length = dup->length;
432 	new.offset = cpu_to_be16((char *)dup - (char *)hdr);
433 
434 	/*
435 	 * Insert at position 0, 1, or 2; or not at all.
436 	 */
437 	if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
438 		dfp[2] = dfp[1];
439 		dfp[1] = dfp[0];
440 		dfp[0] = new;
441 		*loghead = 1;
442 		return &dfp[0];
443 	}
444 	if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
445 		dfp[2] = dfp[1];
446 		dfp[1] = new;
447 		*loghead = 1;
448 		return &dfp[1];
449 	}
450 	if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
451 		dfp[2] = new;
452 		*loghead = 1;
453 		return &dfp[2];
454 	}
455 	return NULL;
456 }
457 
458 /*
459  * Remove a bestfree entry from the table.
460  */
461 STATIC void
462 xfs_dir2_data_freeremove(
463 	struct xfs_dir2_data_hdr *hdr,		/* data block header */
464 	struct xfs_dir2_data_free *bf,		/* bestfree table pointer */
465 	struct xfs_dir2_data_free *dfp,		/* bestfree entry pointer */
466 	int			*loghead)	/* out: log data header */
467 {
468 
469 	ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
470 	       hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
471 	       hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
472 	       hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
473 
474 	/*
475 	 * It's the first entry, slide the next 2 up.
476 	 */
477 	if (dfp == &bf[0]) {
478 		bf[0] = bf[1];
479 		bf[1] = bf[2];
480 	}
481 	/*
482 	 * It's the second entry, slide the 3rd entry up.
483 	 */
484 	else if (dfp == &bf[1])
485 		bf[1] = bf[2];
486 	/*
487 	 * Must be the last entry.
488 	 */
489 	else
490 		ASSERT(dfp == &bf[2]);
491 	/*
492 	 * Clear the 3rd entry, must be zero now.
493 	 */
494 	bf[2].length = 0;
495 	bf[2].offset = 0;
496 	*loghead = 1;
497 }
498 
499 /*
500  * Given a data block, reconstruct its bestfree map.
501  */
502 void
503 xfs_dir2_data_freescan(
504 	struct xfs_inode	*dp,
505 	struct xfs_dir2_data_hdr *hdr,
506 	int			*loghead)
507 {
508 	xfs_dir2_block_tail_t	*btp;		/* block tail */
509 	xfs_dir2_data_entry_t	*dep;		/* active data entry */
510 	xfs_dir2_data_unused_t	*dup;		/* unused data entry */
511 	struct xfs_dir2_data_free *bf;
512 	char			*endp;		/* end of block's data */
513 	char			*p;		/* current entry pointer */
514 	struct xfs_da_geometry	*geo = dp->i_mount->m_dir_geo;
515 
516 	ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
517 	       hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
518 	       hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
519 	       hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
520 
521 	/*
522 	 * Start by clearing the table.
523 	 */
524 	bf = dp->d_ops->data_bestfree_p(hdr);
525 	memset(bf, 0, sizeof(*bf) * XFS_DIR2_DATA_FD_COUNT);
526 	*loghead = 1;
527 	/*
528 	 * Set up pointers.
529 	 */
530 	p = (char *)dp->d_ops->data_entry_p(hdr);
531 	if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
532 	    hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
533 		btp = xfs_dir2_block_tail_p(geo, hdr);
534 		endp = (char *)xfs_dir2_block_leaf_p(btp);
535 	} else
536 		endp = (char *)hdr + geo->blksize;
537 	/*
538 	 * Loop over the block's entries.
539 	 */
540 	while (p < endp) {
541 		dup = (xfs_dir2_data_unused_t *)p;
542 		/*
543 		 * If it's a free entry, insert it.
544 		 */
545 		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
546 			ASSERT((char *)dup - (char *)hdr ==
547 			       be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
548 			xfs_dir2_data_freeinsert(hdr, bf, dup, loghead);
549 			p += be16_to_cpu(dup->length);
550 		}
551 		/*
552 		 * For active entries, check their tags and skip them.
553 		 */
554 		else {
555 			dep = (xfs_dir2_data_entry_t *)p;
556 			ASSERT((char *)dep - (char *)hdr ==
557 			       be16_to_cpu(*dp->d_ops->data_entry_tag_p(dep)));
558 			p += dp->d_ops->data_entsize(dep->namelen);
559 		}
560 	}
561 }
562 
563 /*
564  * Initialize a data block at the given block number in the directory.
565  * Give back the buffer for the created block.
566  */
567 int						/* error */
568 xfs_dir3_data_init(
569 	xfs_da_args_t		*args,		/* directory operation args */
570 	xfs_dir2_db_t		blkno,		/* logical dir block number */
571 	struct xfs_buf		**bpp)		/* output block buffer */
572 {
573 	struct xfs_buf		*bp;		/* block buffer */
574 	xfs_dir2_data_hdr_t	*hdr;		/* data block header */
575 	xfs_inode_t		*dp;		/* incore directory inode */
576 	xfs_dir2_data_unused_t	*dup;		/* unused entry pointer */
577 	struct xfs_dir2_data_free *bf;
578 	int			error;		/* error return value */
579 	int			i;		/* bestfree index */
580 	xfs_mount_t		*mp;		/* filesystem mount point */
581 	xfs_trans_t		*tp;		/* transaction pointer */
582 	int                     t;              /* temp */
583 
584 	dp = args->dp;
585 	mp = dp->i_mount;
586 	tp = args->trans;
587 	/*
588 	 * Get the buffer set up for the block.
589 	 */
590 	error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(args->geo, blkno),
591 			       -1, &bp, XFS_DATA_FORK);
592 	if (error)
593 		return error;
594 	bp->b_ops = &xfs_dir3_data_buf_ops;
595 	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DIR_DATA_BUF);
596 
597 	/*
598 	 * Initialize the header.
599 	 */
600 	hdr = bp->b_addr;
601 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
602 		struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
603 
604 		memset(hdr3, 0, sizeof(*hdr3));
605 		hdr3->magic = cpu_to_be32(XFS_DIR3_DATA_MAGIC);
606 		hdr3->blkno = cpu_to_be64(bp->b_bn);
607 		hdr3->owner = cpu_to_be64(dp->i_ino);
608 		uuid_copy(&hdr3->uuid, &mp->m_sb.sb_meta_uuid);
609 
610 	} else
611 		hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
612 
613 	bf = dp->d_ops->data_bestfree_p(hdr);
614 	bf[0].offset = cpu_to_be16(dp->d_ops->data_entry_offset);
615 	for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
616 		bf[i].length = 0;
617 		bf[i].offset = 0;
618 	}
619 
620 	/*
621 	 * Set up an unused entry for the block's body.
622 	 */
623 	dup = dp->d_ops->data_unused_p(hdr);
624 	dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
625 
626 	t = args->geo->blksize - (uint)dp->d_ops->data_entry_offset;
627 	bf[0].length = cpu_to_be16(t);
628 	dup->length = cpu_to_be16(t);
629 	*xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)hdr);
630 	/*
631 	 * Log it and return it.
632 	 */
633 	xfs_dir2_data_log_header(args, bp);
634 	xfs_dir2_data_log_unused(args, bp, dup);
635 	*bpp = bp;
636 	return 0;
637 }
638 
639 /*
640  * Log an active data entry from the block.
641  */
642 void
643 xfs_dir2_data_log_entry(
644 	struct xfs_da_args	*args,
645 	struct xfs_buf		*bp,
646 	xfs_dir2_data_entry_t	*dep)		/* data entry pointer */
647 {
648 	struct xfs_dir2_data_hdr *hdr = bp->b_addr;
649 
650 	ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
651 	       hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
652 	       hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
653 	       hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
654 
655 	xfs_trans_log_buf(args->trans, bp, (uint)((char *)dep - (char *)hdr),
656 		(uint)((char *)(args->dp->d_ops->data_entry_tag_p(dep) + 1) -
657 		       (char *)hdr - 1));
658 }
659 
660 /*
661  * Log a data block header.
662  */
663 void
664 xfs_dir2_data_log_header(
665 	struct xfs_da_args	*args,
666 	struct xfs_buf		*bp)
667 {
668 #ifdef DEBUG
669 	struct xfs_dir2_data_hdr *hdr = bp->b_addr;
670 
671 	ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
672 	       hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
673 	       hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
674 	       hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
675 #endif
676 
677 	xfs_trans_log_buf(args->trans, bp, 0,
678 			  args->dp->d_ops->data_entry_offset - 1);
679 }
680 
681 /*
682  * Log a data unused entry.
683  */
684 void
685 xfs_dir2_data_log_unused(
686 	struct xfs_da_args	*args,
687 	struct xfs_buf		*bp,
688 	xfs_dir2_data_unused_t	*dup)		/* data unused pointer */
689 {
690 	xfs_dir2_data_hdr_t	*hdr = bp->b_addr;
691 
692 	ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
693 	       hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
694 	       hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
695 	       hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
696 
697 	/*
698 	 * Log the first part of the unused entry.
699 	 */
700 	xfs_trans_log_buf(args->trans, bp, (uint)((char *)dup - (char *)hdr),
701 		(uint)((char *)&dup->length + sizeof(dup->length) -
702 		       1 - (char *)hdr));
703 	/*
704 	 * Log the end (tag) of the unused entry.
705 	 */
706 	xfs_trans_log_buf(args->trans, bp,
707 		(uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
708 		(uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
709 		       sizeof(xfs_dir2_data_off_t) - 1));
710 }
711 
712 /*
713  * Make a byte range in the data block unused.
714  * Its current contents are unimportant.
715  */
716 void
717 xfs_dir2_data_make_free(
718 	struct xfs_da_args	*args,
719 	struct xfs_buf		*bp,
720 	xfs_dir2_data_aoff_t	offset,		/* starting byte offset */
721 	xfs_dir2_data_aoff_t	len,		/* length in bytes */
722 	int			*needlogp,	/* out: log header */
723 	int			*needscanp)	/* out: regen bestfree */
724 {
725 	xfs_dir2_data_hdr_t	*hdr;		/* data block pointer */
726 	xfs_dir2_data_free_t	*dfp;		/* bestfree pointer */
727 	char			*endptr;	/* end of data area */
728 	int			needscan;	/* need to regen bestfree */
729 	xfs_dir2_data_unused_t	*newdup;	/* new unused entry */
730 	xfs_dir2_data_unused_t	*postdup;	/* unused entry after us */
731 	xfs_dir2_data_unused_t	*prevdup;	/* unused entry before us */
732 	struct xfs_dir2_data_free *bf;
733 
734 	hdr = bp->b_addr;
735 
736 	/*
737 	 * Figure out where the end of the data area is.
738 	 */
739 	if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
740 	    hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC))
741 		endptr = (char *)hdr + args->geo->blksize;
742 	else {
743 		xfs_dir2_block_tail_t	*btp;	/* block tail */
744 
745 		ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
746 			hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
747 		btp = xfs_dir2_block_tail_p(args->geo, hdr);
748 		endptr = (char *)xfs_dir2_block_leaf_p(btp);
749 	}
750 	/*
751 	 * If this isn't the start of the block, then back up to
752 	 * the previous entry and see if it's free.
753 	 */
754 	if (offset > args->dp->d_ops->data_entry_offset) {
755 		__be16			*tagp;	/* tag just before us */
756 
757 		tagp = (__be16 *)((char *)hdr + offset) - 1;
758 		prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
759 		if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
760 			prevdup = NULL;
761 	} else
762 		prevdup = NULL;
763 	/*
764 	 * If this isn't the end of the block, see if the entry after
765 	 * us is free.
766 	 */
767 	if ((char *)hdr + offset + len < endptr) {
768 		postdup =
769 			(xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
770 		if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
771 			postdup = NULL;
772 	} else
773 		postdup = NULL;
774 	ASSERT(*needscanp == 0);
775 	needscan = 0;
776 	/*
777 	 * Previous and following entries are both free,
778 	 * merge everything into a single free entry.
779 	 */
780 	bf = args->dp->d_ops->data_bestfree_p(hdr);
781 	if (prevdup && postdup) {
782 		xfs_dir2_data_free_t	*dfp2;	/* another bestfree pointer */
783 
784 		/*
785 		 * See if prevdup and/or postdup are in bestfree table.
786 		 */
787 		dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
788 		dfp2 = xfs_dir2_data_freefind(hdr, bf, postdup);
789 		/*
790 		 * We need a rescan unless there are exactly 2 free entries
791 		 * namely our two.  Then we know what's happening, otherwise
792 		 * since the third bestfree is there, there might be more
793 		 * entries.
794 		 */
795 		needscan = (bf[2].length != 0);
796 		/*
797 		 * Fix up the new big freespace.
798 		 */
799 		be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
800 		*xfs_dir2_data_unused_tag_p(prevdup) =
801 			cpu_to_be16((char *)prevdup - (char *)hdr);
802 		xfs_dir2_data_log_unused(args, bp, prevdup);
803 		if (!needscan) {
804 			/*
805 			 * Has to be the case that entries 0 and 1 are
806 			 * dfp and dfp2 (don't know which is which), and
807 			 * entry 2 is empty.
808 			 * Remove entry 1 first then entry 0.
809 			 */
810 			ASSERT(dfp && dfp2);
811 			if (dfp == &bf[1]) {
812 				dfp = &bf[0];
813 				ASSERT(dfp2 == dfp);
814 				dfp2 = &bf[1];
815 			}
816 			xfs_dir2_data_freeremove(hdr, bf, dfp2, needlogp);
817 			xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
818 			/*
819 			 * Now insert the new entry.
820 			 */
821 			dfp = xfs_dir2_data_freeinsert(hdr, bf, prevdup,
822 						       needlogp);
823 			ASSERT(dfp == &bf[0]);
824 			ASSERT(dfp->length == prevdup->length);
825 			ASSERT(!dfp[1].length);
826 			ASSERT(!dfp[2].length);
827 		}
828 	}
829 	/*
830 	 * The entry before us is free, merge with it.
831 	 */
832 	else if (prevdup) {
833 		dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
834 		be16_add_cpu(&prevdup->length, len);
835 		*xfs_dir2_data_unused_tag_p(prevdup) =
836 			cpu_to_be16((char *)prevdup - (char *)hdr);
837 		xfs_dir2_data_log_unused(args, bp, prevdup);
838 		/*
839 		 * If the previous entry was in the table, the new entry
840 		 * is longer, so it will be in the table too.  Remove
841 		 * the old one and add the new one.
842 		 */
843 		if (dfp) {
844 			xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
845 			xfs_dir2_data_freeinsert(hdr, bf, prevdup, needlogp);
846 		}
847 		/*
848 		 * Otherwise we need a scan if the new entry is big enough.
849 		 */
850 		else {
851 			needscan = be16_to_cpu(prevdup->length) >
852 				   be16_to_cpu(bf[2].length);
853 		}
854 	}
855 	/*
856 	 * The following entry is free, merge with it.
857 	 */
858 	else if (postdup) {
859 		dfp = xfs_dir2_data_freefind(hdr, bf, postdup);
860 		newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
861 		newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
862 		newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
863 		*xfs_dir2_data_unused_tag_p(newdup) =
864 			cpu_to_be16((char *)newdup - (char *)hdr);
865 		xfs_dir2_data_log_unused(args, bp, newdup);
866 		/*
867 		 * If the following entry was in the table, the new entry
868 		 * is longer, so it will be in the table too.  Remove
869 		 * the old one and add the new one.
870 		 */
871 		if (dfp) {
872 			xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
873 			xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
874 		}
875 		/*
876 		 * Otherwise we need a scan if the new entry is big enough.
877 		 */
878 		else {
879 			needscan = be16_to_cpu(newdup->length) >
880 				   be16_to_cpu(bf[2].length);
881 		}
882 	}
883 	/*
884 	 * Neither neighbor is free.  Make a new entry.
885 	 */
886 	else {
887 		newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
888 		newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
889 		newdup->length = cpu_to_be16(len);
890 		*xfs_dir2_data_unused_tag_p(newdup) =
891 			cpu_to_be16((char *)newdup - (char *)hdr);
892 		xfs_dir2_data_log_unused(args, bp, newdup);
893 		xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
894 	}
895 	*needscanp = needscan;
896 }
897 
898 /*
899  * Take a byte range out of an existing unused space and make it un-free.
900  */
901 void
902 xfs_dir2_data_use_free(
903 	struct xfs_da_args	*args,
904 	struct xfs_buf		*bp,
905 	xfs_dir2_data_unused_t	*dup,		/* unused entry */
906 	xfs_dir2_data_aoff_t	offset,		/* starting offset to use */
907 	xfs_dir2_data_aoff_t	len,		/* length to use */
908 	int			*needlogp,	/* out: need to log header */
909 	int			*needscanp)	/* out: need regen bestfree */
910 {
911 	xfs_dir2_data_hdr_t	*hdr;		/* data block header */
912 	xfs_dir2_data_free_t	*dfp;		/* bestfree pointer */
913 	int			matchback;	/* matches end of freespace */
914 	int			matchfront;	/* matches start of freespace */
915 	int			needscan;	/* need to regen bestfree */
916 	xfs_dir2_data_unused_t	*newdup;	/* new unused entry */
917 	xfs_dir2_data_unused_t	*newdup2;	/* another new unused entry */
918 	int			oldlen;		/* old unused entry's length */
919 	struct xfs_dir2_data_free *bf;
920 
921 	hdr = bp->b_addr;
922 	ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
923 	       hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
924 	       hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
925 	       hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
926 	ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
927 	ASSERT(offset >= (char *)dup - (char *)hdr);
928 	ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
929 	ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
930 	/*
931 	 * Look up the entry in the bestfree table.
932 	 */
933 	oldlen = be16_to_cpu(dup->length);
934 	bf = args->dp->d_ops->data_bestfree_p(hdr);
935 	dfp = xfs_dir2_data_freefind(hdr, bf, dup);
936 	ASSERT(dfp || oldlen <= be16_to_cpu(bf[2].length));
937 	/*
938 	 * Check for alignment with front and back of the entry.
939 	 */
940 	matchfront = (char *)dup - (char *)hdr == offset;
941 	matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
942 	ASSERT(*needscanp == 0);
943 	needscan = 0;
944 	/*
945 	 * If we matched it exactly we just need to get rid of it from
946 	 * the bestfree table.
947 	 */
948 	if (matchfront && matchback) {
949 		if (dfp) {
950 			needscan = (bf[2].offset != 0);
951 			if (!needscan)
952 				xfs_dir2_data_freeremove(hdr, bf, dfp,
953 							 needlogp);
954 		}
955 	}
956 	/*
957 	 * We match the first part of the entry.
958 	 * Make a new entry with the remaining freespace.
959 	 */
960 	else if (matchfront) {
961 		newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
962 		newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
963 		newdup->length = cpu_to_be16(oldlen - len);
964 		*xfs_dir2_data_unused_tag_p(newdup) =
965 			cpu_to_be16((char *)newdup - (char *)hdr);
966 		xfs_dir2_data_log_unused(args, bp, newdup);
967 		/*
968 		 * If it was in the table, remove it and add the new one.
969 		 */
970 		if (dfp) {
971 			xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
972 			dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
973 						       needlogp);
974 			ASSERT(dfp != NULL);
975 			ASSERT(dfp->length == newdup->length);
976 			ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
977 			/*
978 			 * If we got inserted at the last slot,
979 			 * that means we don't know if there was a better
980 			 * choice for the last slot, or not.  Rescan.
981 			 */
982 			needscan = dfp == &bf[2];
983 		}
984 	}
985 	/*
986 	 * We match the last part of the entry.
987 	 * Trim the allocated space off the tail of the entry.
988 	 */
989 	else if (matchback) {
990 		newdup = dup;
991 		newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
992 		*xfs_dir2_data_unused_tag_p(newdup) =
993 			cpu_to_be16((char *)newdup - (char *)hdr);
994 		xfs_dir2_data_log_unused(args, bp, newdup);
995 		/*
996 		 * If it was in the table, remove it and add the new one.
997 		 */
998 		if (dfp) {
999 			xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
1000 			dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
1001 						       needlogp);
1002 			ASSERT(dfp != NULL);
1003 			ASSERT(dfp->length == newdup->length);
1004 			ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
1005 			/*
1006 			 * If we got inserted at the last slot,
1007 			 * that means we don't know if there was a better
1008 			 * choice for the last slot, or not.  Rescan.
1009 			 */
1010 			needscan = dfp == &bf[2];
1011 		}
1012 	}
1013 	/*
1014 	 * Poking out the middle of an entry.
1015 	 * Make two new entries.
1016 	 */
1017 	else {
1018 		newdup = dup;
1019 		newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
1020 		*xfs_dir2_data_unused_tag_p(newdup) =
1021 			cpu_to_be16((char *)newdup - (char *)hdr);
1022 		xfs_dir2_data_log_unused(args, bp, newdup);
1023 		newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
1024 		newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
1025 		newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
1026 		*xfs_dir2_data_unused_tag_p(newdup2) =
1027 			cpu_to_be16((char *)newdup2 - (char *)hdr);
1028 		xfs_dir2_data_log_unused(args, bp, newdup2);
1029 		/*
1030 		 * If the old entry was in the table, we need to scan
1031 		 * if the 3rd entry was valid, since these entries
1032 		 * are smaller than the old one.
1033 		 * If we don't need to scan that means there were 1 or 2
1034 		 * entries in the table, and removing the old and adding
1035 		 * the 2 new will work.
1036 		 */
1037 		if (dfp) {
1038 			needscan = (bf[2].length != 0);
1039 			if (!needscan) {
1040 				xfs_dir2_data_freeremove(hdr, bf, dfp,
1041 							 needlogp);
1042 				xfs_dir2_data_freeinsert(hdr, bf, newdup,
1043 							 needlogp);
1044 				xfs_dir2_data_freeinsert(hdr, bf, newdup2,
1045 							 needlogp);
1046 			}
1047 		}
1048 	}
1049 	*needscanp = needscan;
1050 }
1051