xref: /openbmc/linux/fs/xfs/xfs_attr_list.c (revision 842ed298)
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_da_format.h"
15 #include "xfs_inode.h"
16 #include "xfs_trans.h"
17 #include "xfs_bmap.h"
18 #include "xfs_attr.h"
19 #include "xfs_attr_sf.h"
20 #include "xfs_attr_leaf.h"
21 #include "xfs_error.h"
22 #include "xfs_trace.h"
23 #include "xfs_dir2.h"
24 
25 STATIC int
26 xfs_attr_shortform_compare(const void *a, const void *b)
27 {
28 	xfs_attr_sf_sort_t *sa, *sb;
29 
30 	sa = (xfs_attr_sf_sort_t *)a;
31 	sb = (xfs_attr_sf_sort_t *)b;
32 	if (sa->hash < sb->hash) {
33 		return -1;
34 	} else if (sa->hash > sb->hash) {
35 		return 1;
36 	} else {
37 		return sa->entno - sb->entno;
38 	}
39 }
40 
41 #define XFS_ISRESET_CURSOR(cursor) \
42 	(!((cursor)->initted) && !((cursor)->hashval) && \
43 	 !((cursor)->blkno) && !((cursor)->offset))
44 /*
45  * Copy out entries of shortform attribute lists for attr_list().
46  * Shortform attribute lists are not stored in hashval sorted order.
47  * If the output buffer is not large enough to hold them all, then
48  * we have to calculate each entries' hashvalue and sort them before
49  * we can begin returning them to the user.
50  */
51 static int
52 xfs_attr_shortform_list(
53 	struct xfs_attr_list_context	*context)
54 {
55 	struct xfs_attrlist_cursor_kern	*cursor = &context->cursor;
56 	struct xfs_inode		*dp = context->dp;
57 	struct xfs_attr_sf_sort		*sbuf, *sbp;
58 	struct xfs_attr_shortform	*sf;
59 	struct xfs_attr_sf_entry	*sfe;
60 	int				sbsize, nsbuf, count, i;
61 	int				error = 0;
62 
63 	ASSERT(dp->i_afp != NULL);
64 	sf = (struct xfs_attr_shortform *)dp->i_afp->if_u1.if_data;
65 	ASSERT(sf != NULL);
66 	if (!sf->hdr.count)
67 		return 0;
68 
69 	trace_xfs_attr_list_sf(context);
70 
71 	/*
72 	 * If the buffer is large enough and the cursor is at the start,
73 	 * do not bother with sorting since we will return everything in
74 	 * one buffer and another call using the cursor won't need to be
75 	 * made.
76 	 * Note the generous fudge factor of 16 overhead bytes per entry.
77 	 * If bufsize is zero then put_listent must be a search function
78 	 * and can just scan through what we have.
79 	 */
80 	if (context->bufsize == 0 ||
81 	    (XFS_ISRESET_CURSOR(cursor) &&
82 	     (dp->i_afp->if_bytes + sf->hdr.count * 16) < context->bufsize)) {
83 		for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
84 			if (XFS_IS_CORRUPT(context->dp->i_mount,
85 					   !xfs_attr_namecheck(sfe->nameval,
86 							       sfe->namelen)))
87 				return -EFSCORRUPTED;
88 			context->put_listent(context,
89 					     sfe->flags,
90 					     sfe->nameval,
91 					     (int)sfe->namelen,
92 					     (int)sfe->valuelen);
93 			/*
94 			 * Either search callback finished early or
95 			 * didn't fit it all in the buffer after all.
96 			 */
97 			if (context->seen_enough)
98 				break;
99 			sfe = xfs_attr_sf_nextentry(sfe);
100 		}
101 		trace_xfs_attr_list_sf_all(context);
102 		return 0;
103 	}
104 
105 	/* do no more for a search callback */
106 	if (context->bufsize == 0)
107 		return 0;
108 
109 	/*
110 	 * It didn't all fit, so we have to sort everything on hashval.
111 	 */
112 	sbsize = sf->hdr.count * sizeof(*sbuf);
113 	sbp = sbuf = kmem_alloc(sbsize, KM_NOFS);
114 
115 	/*
116 	 * Scan the attribute list for the rest of the entries, storing
117 	 * the relevant info from only those that match into a buffer.
118 	 */
119 	nsbuf = 0;
120 	for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
121 		if (unlikely(
122 		    ((char *)sfe < (char *)sf) ||
123 		    ((char *)sfe >= ((char *)sf + dp->i_afp->if_bytes)))) {
124 			XFS_CORRUPTION_ERROR("xfs_attr_shortform_list",
125 					     XFS_ERRLEVEL_LOW,
126 					     context->dp->i_mount, sfe,
127 					     sizeof(*sfe));
128 			kmem_free(sbuf);
129 			return -EFSCORRUPTED;
130 		}
131 
132 		sbp->entno = i;
133 		sbp->hash = xfs_da_hashname(sfe->nameval, sfe->namelen);
134 		sbp->name = sfe->nameval;
135 		sbp->namelen = sfe->namelen;
136 		/* These are bytes, and both on-disk, don't endian-flip */
137 		sbp->valuelen = sfe->valuelen;
138 		sbp->flags = sfe->flags;
139 		sfe = xfs_attr_sf_nextentry(sfe);
140 		sbp++;
141 		nsbuf++;
142 	}
143 
144 	/*
145 	 * Sort the entries on hash then entno.
146 	 */
147 	xfs_sort(sbuf, nsbuf, sizeof(*sbuf), xfs_attr_shortform_compare);
148 
149 	/*
150 	 * Re-find our place IN THE SORTED LIST.
151 	 */
152 	count = 0;
153 	cursor->initted = 1;
154 	cursor->blkno = 0;
155 	for (sbp = sbuf, i = 0; i < nsbuf; i++, sbp++) {
156 		if (sbp->hash == cursor->hashval) {
157 			if (cursor->offset == count) {
158 				break;
159 			}
160 			count++;
161 		} else if (sbp->hash > cursor->hashval) {
162 			break;
163 		}
164 	}
165 	if (i == nsbuf)
166 		goto out;
167 
168 	/*
169 	 * Loop putting entries into the user buffer.
170 	 */
171 	for ( ; i < nsbuf; i++, sbp++) {
172 		if (cursor->hashval != sbp->hash) {
173 			cursor->hashval = sbp->hash;
174 			cursor->offset = 0;
175 		}
176 		if (XFS_IS_CORRUPT(context->dp->i_mount,
177 				   !xfs_attr_namecheck(sbp->name,
178 						       sbp->namelen))) {
179 			error = -EFSCORRUPTED;
180 			goto out;
181 		}
182 		context->put_listent(context,
183 				     sbp->flags,
184 				     sbp->name,
185 				     sbp->namelen,
186 				     sbp->valuelen);
187 		if (context->seen_enough)
188 			break;
189 		cursor->offset++;
190 	}
191 out:
192 	kmem_free(sbuf);
193 	return error;
194 }
195 
196 /*
197  * We didn't find the block & hash mentioned in the cursor state, so
198  * walk down the attr btree looking for the hash.
199  */
200 STATIC int
201 xfs_attr_node_list_lookup(
202 	struct xfs_attr_list_context	*context,
203 	struct xfs_attrlist_cursor_kern	*cursor,
204 	struct xfs_buf			**pbp)
205 {
206 	struct xfs_da3_icnode_hdr	nodehdr;
207 	struct xfs_da_intnode		*node;
208 	struct xfs_da_node_entry	*btree;
209 	struct xfs_inode		*dp = context->dp;
210 	struct xfs_mount		*mp = dp->i_mount;
211 	struct xfs_trans		*tp = context->tp;
212 	struct xfs_buf			*bp;
213 	int				i;
214 	int				error = 0;
215 	unsigned int			expected_level = 0;
216 	uint16_t			magic;
217 
218 	ASSERT(*pbp == NULL);
219 	cursor->blkno = 0;
220 	for (;;) {
221 		error = xfs_da3_node_read(tp, dp, cursor->blkno, &bp,
222 				XFS_ATTR_FORK);
223 		if (error)
224 			return error;
225 		node = bp->b_addr;
226 		magic = be16_to_cpu(node->hdr.info.magic);
227 		if (magic == XFS_ATTR_LEAF_MAGIC ||
228 		    magic == XFS_ATTR3_LEAF_MAGIC)
229 			break;
230 		if (magic != XFS_DA_NODE_MAGIC &&
231 		    magic != XFS_DA3_NODE_MAGIC) {
232 			XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
233 					node, sizeof(*node));
234 			goto out_corruptbuf;
235 		}
236 
237 		xfs_da3_node_hdr_from_disk(mp, &nodehdr, node);
238 
239 		/* Tree taller than we can handle; bail out! */
240 		if (nodehdr.level >= XFS_DA_NODE_MAXDEPTH)
241 			goto out_corruptbuf;
242 
243 		/* Check the level from the root node. */
244 		if (cursor->blkno == 0)
245 			expected_level = nodehdr.level - 1;
246 		else if (expected_level != nodehdr.level)
247 			goto out_corruptbuf;
248 		else
249 			expected_level--;
250 
251 		btree = nodehdr.btree;
252 		for (i = 0; i < nodehdr.count; btree++, i++) {
253 			if (cursor->hashval <= be32_to_cpu(btree->hashval)) {
254 				cursor->blkno = be32_to_cpu(btree->before);
255 				trace_xfs_attr_list_node_descend(context,
256 						btree);
257 				break;
258 			}
259 		}
260 		xfs_trans_brelse(tp, bp);
261 
262 		if (i == nodehdr.count)
263 			return 0;
264 
265 		/* We can't point back to the root. */
266 		if (XFS_IS_CORRUPT(mp, cursor->blkno == 0))
267 			return -EFSCORRUPTED;
268 	}
269 
270 	if (expected_level != 0)
271 		goto out_corruptbuf;
272 
273 	*pbp = bp;
274 	return 0;
275 
276 out_corruptbuf:
277 	xfs_buf_mark_corrupt(bp);
278 	xfs_trans_brelse(tp, bp);
279 	return -EFSCORRUPTED;
280 }
281 
282 STATIC int
283 xfs_attr_node_list(
284 	struct xfs_attr_list_context	*context)
285 {
286 	struct xfs_attrlist_cursor_kern	*cursor = &context->cursor;
287 	struct xfs_attr3_icleaf_hdr	leafhdr;
288 	struct xfs_attr_leafblock	*leaf;
289 	struct xfs_da_intnode		*node;
290 	struct xfs_buf			*bp;
291 	struct xfs_inode		*dp = context->dp;
292 	struct xfs_mount		*mp = dp->i_mount;
293 	int				error = 0;
294 
295 	trace_xfs_attr_node_list(context);
296 
297 	cursor->initted = 1;
298 
299 	/*
300 	 * Do all sorts of validation on the passed-in cursor structure.
301 	 * If anything is amiss, ignore the cursor and look up the hashval
302 	 * starting from the btree root.
303 	 */
304 	bp = NULL;
305 	if (cursor->blkno > 0) {
306 		error = xfs_da3_node_read(context->tp, dp, cursor->blkno, &bp,
307 				XFS_ATTR_FORK);
308 		if ((error != 0) && (error != -EFSCORRUPTED))
309 			return error;
310 		if (bp) {
311 			struct xfs_attr_leaf_entry *entries;
312 
313 			node = bp->b_addr;
314 			switch (be16_to_cpu(node->hdr.info.magic)) {
315 			case XFS_DA_NODE_MAGIC:
316 			case XFS_DA3_NODE_MAGIC:
317 				trace_xfs_attr_list_wrong_blk(context);
318 				xfs_trans_brelse(context->tp, bp);
319 				bp = NULL;
320 				break;
321 			case XFS_ATTR_LEAF_MAGIC:
322 			case XFS_ATTR3_LEAF_MAGIC:
323 				leaf = bp->b_addr;
324 				xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo,
325 							     &leafhdr, leaf);
326 				entries = xfs_attr3_leaf_entryp(leaf);
327 				if (cursor->hashval > be32_to_cpu(
328 						entries[leafhdr.count - 1].hashval)) {
329 					trace_xfs_attr_list_wrong_blk(context);
330 					xfs_trans_brelse(context->tp, bp);
331 					bp = NULL;
332 				} else if (cursor->hashval <= be32_to_cpu(
333 						entries[0].hashval)) {
334 					trace_xfs_attr_list_wrong_blk(context);
335 					xfs_trans_brelse(context->tp, bp);
336 					bp = NULL;
337 				}
338 				break;
339 			default:
340 				trace_xfs_attr_list_wrong_blk(context);
341 				xfs_trans_brelse(context->tp, bp);
342 				bp = NULL;
343 			}
344 		}
345 	}
346 
347 	/*
348 	 * We did not find what we expected given the cursor's contents,
349 	 * so we start from the top and work down based on the hash value.
350 	 * Note that start of node block is same as start of leaf block.
351 	 */
352 	if (bp == NULL) {
353 		error = xfs_attr_node_list_lookup(context, cursor, &bp);
354 		if (error || !bp)
355 			return error;
356 	}
357 	ASSERT(bp != NULL);
358 
359 	/*
360 	 * Roll upward through the blocks, processing each leaf block in
361 	 * order.  As long as there is space in the result buffer, keep
362 	 * adding the information.
363 	 */
364 	for (;;) {
365 		leaf = bp->b_addr;
366 		error = xfs_attr3_leaf_list_int(bp, context);
367 		if (error)
368 			break;
369 		xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
370 		if (context->seen_enough || leafhdr.forw == 0)
371 			break;
372 		cursor->blkno = leafhdr.forw;
373 		xfs_trans_brelse(context->tp, bp);
374 		error = xfs_attr3_leaf_read(context->tp, dp, cursor->blkno,
375 					    &bp);
376 		if (error)
377 			return error;
378 	}
379 	xfs_trans_brelse(context->tp, bp);
380 	return error;
381 }
382 
383 /*
384  * Copy out attribute list entries for attr_list(), for leaf attribute lists.
385  */
386 int
387 xfs_attr3_leaf_list_int(
388 	struct xfs_buf			*bp,
389 	struct xfs_attr_list_context	*context)
390 {
391 	struct xfs_attrlist_cursor_kern	*cursor = &context->cursor;
392 	struct xfs_attr_leafblock	*leaf;
393 	struct xfs_attr3_icleaf_hdr	ichdr;
394 	struct xfs_attr_leaf_entry	*entries;
395 	struct xfs_attr_leaf_entry	*entry;
396 	int				i;
397 	struct xfs_mount		*mp = context->dp->i_mount;
398 
399 	trace_xfs_attr_list_leaf(context);
400 
401 	leaf = bp->b_addr;
402 	xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr, leaf);
403 	entries = xfs_attr3_leaf_entryp(leaf);
404 
405 	cursor->initted = 1;
406 
407 	/*
408 	 * Re-find our place in the leaf block if this is a new syscall.
409 	 */
410 	if (context->resynch) {
411 		entry = &entries[0];
412 		for (i = 0; i < ichdr.count; entry++, i++) {
413 			if (be32_to_cpu(entry->hashval) == cursor->hashval) {
414 				if (cursor->offset == context->dupcnt) {
415 					context->dupcnt = 0;
416 					break;
417 				}
418 				context->dupcnt++;
419 			} else if (be32_to_cpu(entry->hashval) >
420 					cursor->hashval) {
421 				context->dupcnt = 0;
422 				break;
423 			}
424 		}
425 		if (i == ichdr.count) {
426 			trace_xfs_attr_list_notfound(context);
427 			return 0;
428 		}
429 	} else {
430 		entry = &entries[0];
431 		i = 0;
432 	}
433 	context->resynch = 0;
434 
435 	/*
436 	 * We have found our place, start copying out the new attributes.
437 	 */
438 	for (; i < ichdr.count; entry++, i++) {
439 		char *name;
440 		int namelen, valuelen;
441 
442 		if (be32_to_cpu(entry->hashval) != cursor->hashval) {
443 			cursor->hashval = be32_to_cpu(entry->hashval);
444 			cursor->offset = 0;
445 		}
446 
447 		if ((entry->flags & XFS_ATTR_INCOMPLETE) &&
448 		    !context->allow_incomplete)
449 			continue;
450 
451 		if (entry->flags & XFS_ATTR_LOCAL) {
452 			xfs_attr_leaf_name_local_t *name_loc;
453 
454 			name_loc = xfs_attr3_leaf_name_local(leaf, i);
455 			name = name_loc->nameval;
456 			namelen = name_loc->namelen;
457 			valuelen = be16_to_cpu(name_loc->valuelen);
458 		} else {
459 			xfs_attr_leaf_name_remote_t *name_rmt;
460 
461 			name_rmt = xfs_attr3_leaf_name_remote(leaf, i);
462 			name = name_rmt->name;
463 			namelen = name_rmt->namelen;
464 			valuelen = be32_to_cpu(name_rmt->valuelen);
465 		}
466 
467 		if (XFS_IS_CORRUPT(context->dp->i_mount,
468 				   !xfs_attr_namecheck(name, namelen)))
469 			return -EFSCORRUPTED;
470 		context->put_listent(context, entry->flags,
471 					      name, namelen, valuelen);
472 		if (context->seen_enough)
473 			break;
474 		cursor->offset++;
475 	}
476 	trace_xfs_attr_list_leaf_end(context);
477 	return 0;
478 }
479 
480 /*
481  * Copy out attribute entries for attr_list(), for leaf attribute lists.
482  */
483 STATIC int
484 xfs_attr_leaf_list(
485 	struct xfs_attr_list_context	*context)
486 {
487 	struct xfs_buf			*bp;
488 	int				error;
489 
490 	trace_xfs_attr_leaf_list(context);
491 
492 	context->cursor.blkno = 0;
493 	error = xfs_attr3_leaf_read(context->tp, context->dp, 0, &bp);
494 	if (error)
495 		return error;
496 
497 	error = xfs_attr3_leaf_list_int(bp, context);
498 	xfs_trans_brelse(context->tp, bp);
499 	return error;
500 }
501 
502 int
503 xfs_attr_list_ilocked(
504 	struct xfs_attr_list_context	*context)
505 {
506 	struct xfs_inode		*dp = context->dp;
507 
508 	ASSERT(xfs_isilocked(dp, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
509 
510 	/*
511 	 * Decide on what work routines to call based on the inode size.
512 	 */
513 	if (!xfs_inode_hasattr(dp))
514 		return 0;
515 	if (dp->i_afp->if_format == XFS_DINODE_FMT_LOCAL)
516 		return xfs_attr_shortform_list(context);
517 	if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
518 		return xfs_attr_leaf_list(context);
519 	return xfs_attr_node_list(context);
520 }
521 
522 int
523 xfs_attr_list(
524 	struct xfs_attr_list_context	*context)
525 {
526 	struct xfs_inode		*dp = context->dp;
527 	uint				lock_mode;
528 	int				error;
529 
530 	XFS_STATS_INC(dp->i_mount, xs_attr_list);
531 
532 	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
533 		return -EIO;
534 
535 	lock_mode = xfs_ilock_attr_map_shared(dp);
536 	error = xfs_attr_list_ilocked(context);
537 	xfs_iunlock(dp, lock_mode);
538 	return error;
539 }
540