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Merge branch 'from-linus' into upstream
[deliverable/linux.git] / fs / reiserfs / xattr.c
1 /*
2 * linux/fs/reiserfs/xattr.c
3 *
4 * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com>
5 *
6 */
7
8 /*
9 * In order to implement EA/ACLs in a clean, backwards compatible manner,
10 * they are implemented as files in a "private" directory.
11 * Each EA is in it's own file, with the directory layout like so (/ is assumed
12 * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory,
13 * directories named using the capital-hex form of the objectid and
14 * generation number are used. Inside each directory are individual files
15 * named with the name of the extended attribute.
16 *
17 * So, for objectid 12648430, we could have:
18 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access
19 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default
20 * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type
21 * .. or similar.
22 *
23 * The file contents are the text of the EA. The size is known based on the
24 * stat data describing the file.
25 *
26 * In the case of system.posix_acl_access and system.posix_acl_default, since
27 * these are special cases for filesystem ACLs, they are interpreted by the
28 * kernel, in addition, they are negatively and positively cached and attached
29 * to the inode so that unnecessary lookups are avoided.
30 */
31
32 #include <linux/reiserfs_fs.h>
33 #include <linux/capability.h>
34 #include <linux/dcache.h>
35 #include <linux/namei.h>
36 #include <linux/errno.h>
37 #include <linux/fs.h>
38 #include <linux/file.h>
39 #include <linux/pagemap.h>
40 #include <linux/xattr.h>
41 #include <linux/reiserfs_xattr.h>
42 #include <linux/reiserfs_acl.h>
43 #include <asm/uaccess.h>
44 #include <asm/checksum.h>
45 #include <linux/smp_lock.h>
46 #include <linux/stat.h>
47 #include <asm/semaphore.h>
48
49 #define FL_READONLY 128
50 #define FL_DIR_SEM_HELD 256
51 #define PRIVROOT_NAME ".reiserfs_priv"
52 #define XAROOT_NAME "xattrs"
53
54 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char
55 *prefix);
56
57 static struct dentry *create_xa_root(struct super_block *sb)
58 {
59 struct dentry *privroot = dget(REISERFS_SB(sb)->priv_root);
60 struct dentry *xaroot;
61
62 /* This needs to be created at mount-time */
63 if (!privroot)
64 return ERR_PTR(-EOPNOTSUPP);
65
66 xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME));
67 if (IS_ERR(xaroot)) {
68 goto out;
69 } else if (!xaroot->d_inode) {
70 int err;
71 mutex_lock(&privroot->d_inode->i_mutex);
72 err =
73 privroot->d_inode->i_op->mkdir(privroot->d_inode, xaroot,
74 0700);
75 mutex_unlock(&privroot->d_inode->i_mutex);
76
77 if (err) {
78 dput(xaroot);
79 dput(privroot);
80 return ERR_PTR(err);
81 }
82 REISERFS_SB(sb)->xattr_root = dget(xaroot);
83 }
84
85 out:
86 dput(privroot);
87 return xaroot;
88 }
89
90 /* This will return a dentry, or error, refering to the xa root directory.
91 * If the xa root doesn't exist yet, the dentry will be returned without
92 * an associated inode. This dentry can be used with ->mkdir to create
93 * the xa directory. */
94 static struct dentry *__get_xa_root(struct super_block *s)
95 {
96 struct dentry *privroot = dget(REISERFS_SB(s)->priv_root);
97 struct dentry *xaroot = NULL;
98
99 if (IS_ERR(privroot) || !privroot)
100 return privroot;
101
102 xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME));
103 if (IS_ERR(xaroot)) {
104 goto out;
105 } else if (!xaroot->d_inode) {
106 dput(xaroot);
107 xaroot = NULL;
108 goto out;
109 }
110
111 REISERFS_SB(s)->xattr_root = dget(xaroot);
112
113 out:
114 dput(privroot);
115 return xaroot;
116 }
117
118 /* Returns the dentry (or NULL) referring to the root of the extended
119 * attribute directory tree. If it has already been retrieved, it is used.
120 * Otherwise, we attempt to retrieve it from disk. It may also return
121 * a pointer-encoded error.
122 */
123 static inline struct dentry *get_xa_root(struct super_block *s)
124 {
125 struct dentry *dentry = dget(REISERFS_SB(s)->xattr_root);
126
127 if (!dentry)
128 dentry = __get_xa_root(s);
129
130 return dentry;
131 }
132
133 /* Opens the directory corresponding to the inode's extended attribute store.
134 * If flags allow, the tree to the directory may be created. If creation is
135 * prohibited, -ENODATA is returned. */
136 static struct dentry *open_xa_dir(const struct inode *inode, int flags)
137 {
138 struct dentry *xaroot, *xadir;
139 char namebuf[17];
140
141 xaroot = get_xa_root(inode->i_sb);
142 if (IS_ERR(xaroot)) {
143 return xaroot;
144 } else if (!xaroot) {
145 if (flags == 0 || flags & XATTR_CREATE) {
146 xaroot = create_xa_root(inode->i_sb);
147 if (IS_ERR(xaroot))
148 return xaroot;
149 }
150 if (!xaroot)
151 return ERR_PTR(-ENODATA);
152 }
153
154 /* ok, we have xaroot open */
155
156 snprintf(namebuf, sizeof(namebuf), "%X.%X",
157 le32_to_cpu(INODE_PKEY(inode)->k_objectid),
158 inode->i_generation);
159 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
160 if (IS_ERR(xadir)) {
161 dput(xaroot);
162 return xadir;
163 }
164
165 if (!xadir->d_inode) {
166 int err;
167 if (flags == 0 || flags & XATTR_CREATE) {
168 /* Although there is nothing else trying to create this directory,
169 * another directory with the same hash may be created, so we need
170 * to protect against that */
171 err =
172 xaroot->d_inode->i_op->mkdir(xaroot->d_inode, xadir,
173 0700);
174 if (err) {
175 dput(xaroot);
176 dput(xadir);
177 return ERR_PTR(err);
178 }
179 }
180 if (!xadir->d_inode) {
181 dput(xaroot);
182 dput(xadir);
183 return ERR_PTR(-ENODATA);
184 }
185 }
186
187 dput(xaroot);
188 return xadir;
189 }
190
191 /* Returns a dentry corresponding to a specific extended attribute file
192 * for the inode. If flags allow, the file is created. Otherwise, a
193 * valid or negative dentry, or an error is returned. */
194 static struct dentry *get_xa_file_dentry(const struct inode *inode,
195 const char *name, int flags)
196 {
197 struct dentry *xadir, *xafile;
198 int err = 0;
199
200 xadir = open_xa_dir(inode, flags);
201 if (IS_ERR(xadir)) {
202 return ERR_PTR(PTR_ERR(xadir));
203 } else if (xadir && !xadir->d_inode) {
204 dput(xadir);
205 return ERR_PTR(-ENODATA);
206 }
207
208 xafile = lookup_one_len(name, xadir, strlen(name));
209 if (IS_ERR(xafile)) {
210 dput(xadir);
211 return ERR_PTR(PTR_ERR(xafile));
212 }
213
214 if (xafile->d_inode) { /* file exists */
215 if (flags & XATTR_CREATE) {
216 err = -EEXIST;
217 dput(xafile);
218 goto out;
219 }
220 } else if (flags & XATTR_REPLACE || flags & FL_READONLY) {
221 goto out;
222 } else {
223 /* inode->i_mutex is down, so nothing else can try to create
224 * the same xattr */
225 err = xadir->d_inode->i_op->create(xadir->d_inode, xafile,
226 0700 | S_IFREG, NULL);
227
228 if (err) {
229 dput(xafile);
230 goto out;
231 }
232 }
233
234 out:
235 dput(xadir);
236 if (err)
237 xafile = ERR_PTR(err);
238 return xafile;
239 }
240
241 /* Opens a file pointer to the attribute associated with inode */
242 static struct file *open_xa_file(const struct inode *inode, const char *name,
243 int flags)
244 {
245 struct dentry *xafile;
246 struct file *fp;
247
248 xafile = get_xa_file_dentry(inode, name, flags);
249 if (IS_ERR(xafile))
250 return ERR_PTR(PTR_ERR(xafile));
251 else if (!xafile->d_inode) {
252 dput(xafile);
253 return ERR_PTR(-ENODATA);
254 }
255
256 fp = dentry_open(xafile, NULL, O_RDWR);
257 /* dentry_open dputs the dentry if it fails */
258
259 return fp;
260 }
261
262 /*
263 * this is very similar to fs/reiserfs/dir.c:reiserfs_readdir, but
264 * we need to drop the path before calling the filldir struct. That
265 * would be a big performance hit to the non-xattr case, so I've copied
266 * the whole thing for now. --clm
267 *
268 * the big difference is that I go backwards through the directory,
269 * and don't mess with f->f_pos, but the idea is the same. Do some
270 * action on each and every entry in the directory.
271 *
272 * we're called with i_mutex held, so there are no worries about the directory
273 * changing underneath us.
274 */
275 static int __xattr_readdir(struct file *filp, void *dirent, filldir_t filldir)
276 {
277 struct inode *inode = filp->f_dentry->d_inode;
278 struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
279 INITIALIZE_PATH(path_to_entry);
280 struct buffer_head *bh;
281 int entry_num;
282 struct item_head *ih, tmp_ih;
283 int search_res;
284 char *local_buf;
285 loff_t next_pos;
286 char small_buf[32]; /* avoid kmalloc if we can */
287 struct reiserfs_de_head *deh;
288 int d_reclen;
289 char *d_name;
290 off_t d_off;
291 ino_t d_ino;
292 struct reiserfs_dir_entry de;
293
294 /* form key for search the next directory entry using f_pos field of
295 file structure */
296 next_pos = max_reiserfs_offset(inode);
297
298 while (1) {
299 research:
300 if (next_pos <= DOT_DOT_OFFSET)
301 break;
302 make_cpu_key(&pos_key, inode, next_pos, TYPE_DIRENTRY, 3);
303
304 search_res =
305 search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
306 &de);
307 if (search_res == IO_ERROR) {
308 // FIXME: we could just skip part of directory which could
309 // not be read
310 pathrelse(&path_to_entry);
311 return -EIO;
312 }
313
314 if (search_res == NAME_NOT_FOUND)
315 de.de_entry_num--;
316
317 set_de_name_and_namelen(&de);
318 entry_num = de.de_entry_num;
319 deh = &(de.de_deh[entry_num]);
320
321 bh = de.de_bh;
322 ih = de.de_ih;
323
324 if (!is_direntry_le_ih(ih)) {
325 reiserfs_warning(inode->i_sb, "not direntry %h", ih);
326 break;
327 }
328 copy_item_head(&tmp_ih, ih);
329
330 /* we must have found item, that is item of this directory, */
331 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
332 "vs-9000: found item %h does not match to dir we readdir %K",
333 ih, &pos_key);
334
335 if (deh_offset(deh) <= DOT_DOT_OFFSET) {
336 break;
337 }
338
339 /* look for the previous entry in the directory */
340 next_pos = deh_offset(deh) - 1;
341
342 if (!de_visible(deh))
343 /* it is hidden entry */
344 continue;
345
346 d_reclen = entry_length(bh, ih, entry_num);
347 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
348 d_off = deh_offset(deh);
349 d_ino = deh_objectid(deh);
350
351 if (!d_name[d_reclen - 1])
352 d_reclen = strlen(d_name);
353
354 if (d_reclen > REISERFS_MAX_NAME(inode->i_sb->s_blocksize)) {
355 /* too big to send back to VFS */
356 continue;
357 }
358
359 /* Ignore the .reiserfs_priv entry */
360 if (reiserfs_xattrs(inode->i_sb) &&
361 !old_format_only(inode->i_sb) &&
362 deh_objectid(deh) ==
363 le32_to_cpu(INODE_PKEY
364 (REISERFS_SB(inode->i_sb)->priv_root->d_inode)->
365 k_objectid))
366 continue;
367
368 if (d_reclen <= 32) {
369 local_buf = small_buf;
370 } else {
371 local_buf = kmalloc(d_reclen, GFP_NOFS);
372 if (!local_buf) {
373 pathrelse(&path_to_entry);
374 return -ENOMEM;
375 }
376 if (item_moved(&tmp_ih, &path_to_entry)) {
377 kfree(local_buf);
378
379 /* sigh, must retry. Do this same offset again */
380 next_pos = d_off;
381 goto research;
382 }
383 }
384
385 // Note, that we copy name to user space via temporary
386 // buffer (local_buf) because filldir will block if
387 // user space buffer is swapped out. At that time
388 // entry can move to somewhere else
389 memcpy(local_buf, d_name, d_reclen);
390
391 /* the filldir function might need to start transactions,
392 * or do who knows what. Release the path now that we've
393 * copied all the important stuff out of the deh
394 */
395 pathrelse(&path_to_entry);
396
397 if (filldir(dirent, local_buf, d_reclen, d_off, d_ino,
398 DT_UNKNOWN) < 0) {
399 if (local_buf != small_buf) {
400 kfree(local_buf);
401 }
402 goto end;
403 }
404 if (local_buf != small_buf) {
405 kfree(local_buf);
406 }
407 } /* while */
408
409 end:
410 pathrelse(&path_to_entry);
411 return 0;
412 }
413
414 /*
415 * this could be done with dedicated readdir ops for the xattr files,
416 * but I want to get something working asap
417 * this is stolen from vfs_readdir
418 *
419 */
420 static
421 int xattr_readdir(struct file *file, filldir_t filler, void *buf)
422 {
423 struct inode *inode = file->f_dentry->d_inode;
424 int res = -ENOTDIR;
425 if (!file->f_op || !file->f_op->readdir)
426 goto out;
427 mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR);
428 // down(&inode->i_zombie);
429 res = -ENOENT;
430 if (!IS_DEADDIR(inode)) {
431 lock_kernel();
432 res = __xattr_readdir(file, buf, filler);
433 unlock_kernel();
434 }
435 // up(&inode->i_zombie);
436 mutex_unlock(&inode->i_mutex);
437 out:
438 return res;
439 }
440
441 /* Internal operations on file data */
442 static inline void reiserfs_put_page(struct page *page)
443 {
444 kunmap(page);
445 page_cache_release(page);
446 }
447
448 static struct page *reiserfs_get_page(struct inode *dir, unsigned long n)
449 {
450 struct address_space *mapping = dir->i_mapping;
451 struct page *page;
452 /* We can deadlock if we try to free dentries,
453 and an unlink/rmdir has just occured - GFP_NOFS avoids this */
454 mapping_set_gfp_mask(mapping, GFP_NOFS);
455 page = read_mapping_page(mapping, n, NULL);
456 if (!IS_ERR(page)) {
457 wait_on_page_locked(page);
458 kmap(page);
459 if (!PageUptodate(page))
460 goto fail;
461
462 if (PageError(page))
463 goto fail;
464 }
465 return page;
466
467 fail:
468 reiserfs_put_page(page);
469 return ERR_PTR(-EIO);
470 }
471
472 static inline __u32 xattr_hash(const char *msg, int len)
473 {
474 return csum_partial(msg, len, 0);
475 }
476
477 /* Generic extended attribute operations that can be used by xa plugins */
478
479 /*
480 * inode->i_mutex: down
481 */
482 int
483 reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer,
484 size_t buffer_size, int flags)
485 {
486 int err = 0;
487 struct file *fp;
488 struct page *page;
489 char *data;
490 struct address_space *mapping;
491 size_t file_pos = 0;
492 size_t buffer_pos = 0;
493 struct inode *xinode;
494 struct iattr newattrs;
495 __u32 xahash = 0;
496
497 if (get_inode_sd_version(inode) == STAT_DATA_V1)
498 return -EOPNOTSUPP;
499
500 /* Empty xattrs are ok, they're just empty files, no hash */
501 if (buffer && buffer_size)
502 xahash = xattr_hash(buffer, buffer_size);
503
504 open_file:
505 fp = open_xa_file(inode, name, flags);
506 if (IS_ERR(fp)) {
507 err = PTR_ERR(fp);
508 goto out;
509 }
510
511 xinode = fp->f_dentry->d_inode;
512 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
513
514 /* we need to copy it off.. */
515 if (xinode->i_nlink > 1) {
516 fput(fp);
517 err = reiserfs_xattr_del(inode, name);
518 if (err < 0)
519 goto out;
520 /* We just killed the old one, we're not replacing anymore */
521 if (flags & XATTR_REPLACE)
522 flags &= ~XATTR_REPLACE;
523 goto open_file;
524 }
525
526 /* Resize it so we're ok to write there */
527 newattrs.ia_size = buffer_size;
528 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
529 mutex_lock(&xinode->i_mutex);
530 err = notify_change(fp->f_dentry, &newattrs);
531 if (err)
532 goto out_filp;
533
534 mapping = xinode->i_mapping;
535 while (buffer_pos < buffer_size || buffer_pos == 0) {
536 size_t chunk;
537 size_t skip = 0;
538 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1));
539 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE)
540 chunk = PAGE_CACHE_SIZE;
541 else
542 chunk = buffer_size - buffer_pos;
543
544 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT);
545 if (IS_ERR(page)) {
546 err = PTR_ERR(page);
547 goto out_filp;
548 }
549
550 lock_page(page);
551 data = page_address(page);
552
553 if (file_pos == 0) {
554 struct reiserfs_xattr_header *rxh;
555 skip = file_pos = sizeof(struct reiserfs_xattr_header);
556 if (chunk + skip > PAGE_CACHE_SIZE)
557 chunk = PAGE_CACHE_SIZE - skip;
558 rxh = (struct reiserfs_xattr_header *)data;
559 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC);
560 rxh->h_hash = cpu_to_le32(xahash);
561 }
562
563 err = mapping->a_ops->prepare_write(fp, page, page_offset,
564 page_offset + chunk + skip);
565 if (!err) {
566 if (buffer)
567 memcpy(data + skip, buffer + buffer_pos, chunk);
568 err =
569 mapping->a_ops->commit_write(fp, page, page_offset,
570 page_offset + chunk +
571 skip);
572 }
573 unlock_page(page);
574 reiserfs_put_page(page);
575 buffer_pos += chunk;
576 file_pos += chunk;
577 skip = 0;
578 if (err || buffer_size == 0 || !buffer)
579 break;
580 }
581
582 /* We can't mark the inode dirty if it's not hashed. This is the case
583 * when we're inheriting the default ACL. If we dirty it, the inode
584 * gets marked dirty, but won't (ever) make it onto the dirty list until
585 * it's synced explicitly to clear I_DIRTY. This is bad. */
586 if (!hlist_unhashed(&inode->i_hash)) {
587 inode->i_ctime = CURRENT_TIME_SEC;
588 mark_inode_dirty(inode);
589 }
590
591 out_filp:
592 mutex_unlock(&xinode->i_mutex);
593 fput(fp);
594
595 out:
596 return err;
597 }
598
599 /*
600 * inode->i_mutex: down
601 */
602 int
603 reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer,
604 size_t buffer_size)
605 {
606 ssize_t err = 0;
607 struct file *fp;
608 size_t isize;
609 size_t file_pos = 0;
610 size_t buffer_pos = 0;
611 struct page *page;
612 struct inode *xinode;
613 __u32 hash = 0;
614
615 if (name == NULL)
616 return -EINVAL;
617
618 /* We can't have xattrs attached to v1 items since they don't have
619 * generation numbers */
620 if (get_inode_sd_version(inode) == STAT_DATA_V1)
621 return -EOPNOTSUPP;
622
623 fp = open_xa_file(inode, name, FL_READONLY);
624 if (IS_ERR(fp)) {
625 err = PTR_ERR(fp);
626 goto out;
627 }
628
629 xinode = fp->f_dentry->d_inode;
630 isize = xinode->i_size;
631 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
632
633 /* Just return the size needed */
634 if (buffer == NULL) {
635 err = isize - sizeof(struct reiserfs_xattr_header);
636 goto out_dput;
637 }
638
639 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) {
640 err = -ERANGE;
641 goto out_dput;
642 }
643
644 while (file_pos < isize) {
645 size_t chunk;
646 char *data;
647 size_t skip = 0;
648 if (isize - file_pos > PAGE_CACHE_SIZE)
649 chunk = PAGE_CACHE_SIZE;
650 else
651 chunk = isize - file_pos;
652
653 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT);
654 if (IS_ERR(page)) {
655 err = PTR_ERR(page);
656 goto out_dput;
657 }
658
659 lock_page(page);
660 data = page_address(page);
661 if (file_pos == 0) {
662 struct reiserfs_xattr_header *rxh =
663 (struct reiserfs_xattr_header *)data;
664 skip = file_pos = sizeof(struct reiserfs_xattr_header);
665 chunk -= skip;
666 /* Magic doesn't match up.. */
667 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) {
668 unlock_page(page);
669 reiserfs_put_page(page);
670 reiserfs_warning(inode->i_sb,
671 "Invalid magic for xattr (%s) "
672 "associated with %k", name,
673 INODE_PKEY(inode));
674 err = -EIO;
675 goto out_dput;
676 }
677 hash = le32_to_cpu(rxh->h_hash);
678 }
679 memcpy(buffer + buffer_pos, data + skip, chunk);
680 unlock_page(page);
681 reiserfs_put_page(page);
682 file_pos += chunk;
683 buffer_pos += chunk;
684 skip = 0;
685 }
686 err = isize - sizeof(struct reiserfs_xattr_header);
687
688 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) !=
689 hash) {
690 reiserfs_warning(inode->i_sb,
691 "Invalid hash for xattr (%s) associated "
692 "with %k", name, INODE_PKEY(inode));
693 err = -EIO;
694 }
695
696 out_dput:
697 fput(fp);
698
699 out:
700 return err;
701 }
702
703 static int
704 __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen)
705 {
706 struct dentry *dentry;
707 struct inode *dir = xadir->d_inode;
708 int err = 0;
709
710 dentry = lookup_one_len(name, xadir, namelen);
711 if (IS_ERR(dentry)) {
712 err = PTR_ERR(dentry);
713 goto out;
714 } else if (!dentry->d_inode) {
715 err = -ENODATA;
716 goto out_file;
717 }
718
719 /* Skip directories.. */
720 if (S_ISDIR(dentry->d_inode->i_mode))
721 goto out_file;
722
723 if (!is_reiserfs_priv_object(dentry->d_inode)) {
724 reiserfs_warning(dir->i_sb, "OID %08x [%.*s/%.*s] doesn't have "
725 "priv flag set [parent is %sset].",
726 le32_to_cpu(INODE_PKEY(dentry->d_inode)->
727 k_objectid), xadir->d_name.len,
728 xadir->d_name.name, namelen, name,
729 is_reiserfs_priv_object(xadir->
730 d_inode) ? "" :
731 "not ");
732 dput(dentry);
733 return -EIO;
734 }
735
736 err = dir->i_op->unlink(dir, dentry);
737 if (!err)
738 d_delete(dentry);
739
740 out_file:
741 dput(dentry);
742
743 out:
744 return err;
745 }
746
747 int reiserfs_xattr_del(struct inode *inode, const char *name)
748 {
749 struct dentry *dir;
750 int err;
751
752 dir = open_xa_dir(inode, FL_READONLY);
753 if (IS_ERR(dir)) {
754 err = PTR_ERR(dir);
755 goto out;
756 }
757
758 err = __reiserfs_xattr_del(dir, name, strlen(name));
759 dput(dir);
760
761 if (!err) {
762 inode->i_ctime = CURRENT_TIME_SEC;
763 mark_inode_dirty(inode);
764 }
765
766 out:
767 return err;
768 }
769
770 /* The following are side effects of other operations that aren't explicitly
771 * modifying extended attributes. This includes operations such as permissions
772 * or ownership changes, object deletions, etc. */
773
774 static int
775 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen,
776 loff_t offset, ino_t ino, unsigned int d_type)
777 {
778 struct dentry *xadir = (struct dentry *)buf;
779
780 return __reiserfs_xattr_del(xadir, name, namelen);
781
782 }
783
784 /* This is called w/ inode->i_mutex downed */
785 int reiserfs_delete_xattrs(struct inode *inode)
786 {
787 struct file *fp;
788 struct dentry *dir, *root;
789 int err = 0;
790
791 /* Skip out, an xattr has no xattrs associated with it */
792 if (is_reiserfs_priv_object(inode) ||
793 get_inode_sd_version(inode) == STAT_DATA_V1 ||
794 !reiserfs_xattrs(inode->i_sb)) {
795 return 0;
796 }
797 reiserfs_read_lock_xattrs(inode->i_sb);
798 dir = open_xa_dir(inode, FL_READONLY);
799 reiserfs_read_unlock_xattrs(inode->i_sb);
800 if (IS_ERR(dir)) {
801 err = PTR_ERR(dir);
802 goto out;
803 } else if (!dir->d_inode) {
804 dput(dir);
805 return 0;
806 }
807
808 fp = dentry_open(dir, NULL, O_RDWR);
809 if (IS_ERR(fp)) {
810 err = PTR_ERR(fp);
811 /* dentry_open dputs the dentry if it fails */
812 goto out;
813 }
814
815 lock_kernel();
816 err = xattr_readdir(fp, reiserfs_delete_xattrs_filler, dir);
817 if (err) {
818 unlock_kernel();
819 goto out_dir;
820 }
821
822 /* Leftovers besides . and .. -- that's not good. */
823 if (dir->d_inode->i_nlink <= 2) {
824 root = get_xa_root(inode->i_sb);
825 reiserfs_write_lock_xattrs(inode->i_sb);
826 err = vfs_rmdir(root->d_inode, dir);
827 reiserfs_write_unlock_xattrs(inode->i_sb);
828 dput(root);
829 } else {
830 reiserfs_warning(inode->i_sb,
831 "Couldn't remove all entries in directory");
832 }
833 unlock_kernel();
834
835 out_dir:
836 fput(fp);
837
838 out:
839 if (!err)
840 REISERFS_I(inode)->i_flags =
841 REISERFS_I(inode)->i_flags & ~i_has_xattr_dir;
842 return err;
843 }
844
845 struct reiserfs_chown_buf {
846 struct inode *inode;
847 struct dentry *xadir;
848 struct iattr *attrs;
849 };
850
851 /* XXX: If there is a better way to do this, I'd love to hear about it */
852 static int
853 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen,
854 loff_t offset, ino_t ino, unsigned int d_type)
855 {
856 struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf;
857 struct dentry *xafile, *xadir = chown_buf->xadir;
858 struct iattr *attrs = chown_buf->attrs;
859 int err = 0;
860
861 xafile = lookup_one_len(name, xadir, namelen);
862 if (IS_ERR(xafile))
863 return PTR_ERR(xafile);
864 else if (!xafile->d_inode) {
865 dput(xafile);
866 return -ENODATA;
867 }
868
869 if (!S_ISDIR(xafile->d_inode->i_mode))
870 err = notify_change(xafile, attrs);
871 dput(xafile);
872
873 return err;
874 }
875
876 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
877 {
878 struct file *fp;
879 struct dentry *dir;
880 int err = 0;
881 struct reiserfs_chown_buf buf;
882 unsigned int ia_valid = attrs->ia_valid;
883
884 /* Skip out, an xattr has no xattrs associated with it */
885 if (is_reiserfs_priv_object(inode) ||
886 get_inode_sd_version(inode) == STAT_DATA_V1 ||
887 !reiserfs_xattrs(inode->i_sb)) {
888 return 0;
889 }
890 reiserfs_read_lock_xattrs(inode->i_sb);
891 dir = open_xa_dir(inode, FL_READONLY);
892 reiserfs_read_unlock_xattrs(inode->i_sb);
893 if (IS_ERR(dir)) {
894 if (PTR_ERR(dir) != -ENODATA)
895 err = PTR_ERR(dir);
896 goto out;
897 } else if (!dir->d_inode) {
898 dput(dir);
899 goto out;
900 }
901
902 fp = dentry_open(dir, NULL, O_RDWR);
903 if (IS_ERR(fp)) {
904 err = PTR_ERR(fp);
905 /* dentry_open dputs the dentry if it fails */
906 goto out;
907 }
908
909 lock_kernel();
910
911 attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME);
912 buf.xadir = dir;
913 buf.attrs = attrs;
914 buf.inode = inode;
915
916 err = xattr_readdir(fp, reiserfs_chown_xattrs_filler, &buf);
917 if (err) {
918 unlock_kernel();
919 goto out_dir;
920 }
921
922 err = notify_change(dir, attrs);
923 unlock_kernel();
924
925 out_dir:
926 fput(fp);
927
928 out:
929 attrs->ia_valid = ia_valid;
930 return err;
931 }
932
933 /* Actual operations that are exported to VFS-land */
934
935 /*
936 * Inode operation getxattr()
937 * Preliminary locking: we down dentry->d_inode->i_mutex
938 */
939 ssize_t
940 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer,
941 size_t size)
942 {
943 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name);
944 int err;
945
946 if (!xah || !reiserfs_xattrs(dentry->d_sb) ||
947 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1)
948 return -EOPNOTSUPP;
949
950 reiserfs_read_lock_xattr_i(dentry->d_inode);
951 reiserfs_read_lock_xattrs(dentry->d_sb);
952 err = xah->get(dentry->d_inode, name, buffer, size);
953 reiserfs_read_unlock_xattrs(dentry->d_sb);
954 reiserfs_read_unlock_xattr_i(dentry->d_inode);
955 return err;
956 }
957
958 /*
959 * Inode operation setxattr()
960 *
961 * dentry->d_inode->i_mutex down
962 */
963 int
964 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value,
965 size_t size, int flags)
966 {
967 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name);
968 int err;
969 int lock;
970
971 if (!xah || !reiserfs_xattrs(dentry->d_sb) ||
972 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1)
973 return -EOPNOTSUPP;
974
975 reiserfs_write_lock_xattr_i(dentry->d_inode);
976 lock = !has_xattr_dir(dentry->d_inode);
977 if (lock)
978 reiserfs_write_lock_xattrs(dentry->d_sb);
979 else
980 reiserfs_read_lock_xattrs(dentry->d_sb);
981 err = xah->set(dentry->d_inode, name, value, size, flags);
982 if (lock)
983 reiserfs_write_unlock_xattrs(dentry->d_sb);
984 else
985 reiserfs_read_unlock_xattrs(dentry->d_sb);
986 reiserfs_write_unlock_xattr_i(dentry->d_inode);
987 return err;
988 }
989
990 /*
991 * Inode operation removexattr()
992 *
993 * dentry->d_inode->i_mutex down
994 */
995 int reiserfs_removexattr(struct dentry *dentry, const char *name)
996 {
997 int err;
998 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name);
999
1000 if (!xah || !reiserfs_xattrs(dentry->d_sb) ||
1001 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1)
1002 return -EOPNOTSUPP;
1003
1004 reiserfs_write_lock_xattr_i(dentry->d_inode);
1005 reiserfs_read_lock_xattrs(dentry->d_sb);
1006
1007 /* Deletion pre-operation */
1008 if (xah->del) {
1009 err = xah->del(dentry->d_inode, name);
1010 if (err)
1011 goto out;
1012 }
1013
1014 err = reiserfs_xattr_del(dentry->d_inode, name);
1015
1016 dentry->d_inode->i_ctime = CURRENT_TIME_SEC;
1017 mark_inode_dirty(dentry->d_inode);
1018
1019 out:
1020 reiserfs_read_unlock_xattrs(dentry->d_sb);
1021 reiserfs_write_unlock_xattr_i(dentry->d_inode);
1022 return err;
1023 }
1024
1025 /* This is what filldir will use:
1026 * r_pos will always contain the amount of space required for the entire
1027 * list. If r_pos becomes larger than r_size, we need more space and we
1028 * return an error indicating this. If r_pos is less than r_size, then we've
1029 * filled the buffer successfully and we return success */
1030 struct reiserfs_listxattr_buf {
1031 int r_pos;
1032 int r_size;
1033 char *r_buf;
1034 struct inode *r_inode;
1035 };
1036
1037 static int
1038 reiserfs_listxattr_filler(void *buf, const char *name, int namelen,
1039 loff_t offset, ino_t ino, unsigned int d_type)
1040 {
1041 struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf;
1042 int len = 0;
1043 if (name[0] != '.'
1044 || (namelen != 1 && (name[1] != '.' || namelen != 2))) {
1045 struct reiserfs_xattr_handler *xah =
1046 find_xattr_handler_prefix(name);
1047 if (!xah)
1048 return 0; /* Unsupported xattr name, skip it */
1049
1050 /* We call ->list() twice because the operation isn't required to just
1051 * return the name back - we want to make sure we have enough space */
1052 len += xah->list(b->r_inode, name, namelen, NULL);
1053
1054 if (len) {
1055 if (b->r_pos + len + 1 <= b->r_size) {
1056 char *p = b->r_buf + b->r_pos;
1057 p += xah->list(b->r_inode, name, namelen, p);
1058 *p++ = '\0';
1059 }
1060 b->r_pos += len + 1;
1061 }
1062 }
1063
1064 return 0;
1065 }
1066
1067 /*
1068 * Inode operation listxattr()
1069 *
1070 * Preliminary locking: we down dentry->d_inode->i_mutex
1071 */
1072 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
1073 {
1074 struct file *fp;
1075 struct dentry *dir;
1076 int err = 0;
1077 struct reiserfs_listxattr_buf buf;
1078
1079 if (!dentry->d_inode)
1080 return -EINVAL;
1081
1082 if (!reiserfs_xattrs(dentry->d_sb) ||
1083 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1)
1084 return -EOPNOTSUPP;
1085
1086 reiserfs_read_lock_xattr_i(dentry->d_inode);
1087 reiserfs_read_lock_xattrs(dentry->d_sb);
1088 dir = open_xa_dir(dentry->d_inode, FL_READONLY);
1089 reiserfs_read_unlock_xattrs(dentry->d_sb);
1090 if (IS_ERR(dir)) {
1091 err = PTR_ERR(dir);
1092 if (err == -ENODATA)
1093 err = 0; /* Not an error if there aren't any xattrs */
1094 goto out;
1095 }
1096
1097 fp = dentry_open(dir, NULL, O_RDWR);
1098 if (IS_ERR(fp)) {
1099 err = PTR_ERR(fp);
1100 /* dentry_open dputs the dentry if it fails */
1101 goto out;
1102 }
1103
1104 buf.r_buf = buffer;
1105 buf.r_size = buffer ? size : 0;
1106 buf.r_pos = 0;
1107 buf.r_inode = dentry->d_inode;
1108
1109 REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir;
1110
1111 err = xattr_readdir(fp, reiserfs_listxattr_filler, &buf);
1112 if (err)
1113 goto out_dir;
1114
1115 if (buf.r_pos > buf.r_size && buffer != NULL)
1116 err = -ERANGE;
1117 else
1118 err = buf.r_pos;
1119
1120 out_dir:
1121 fput(fp);
1122
1123 out:
1124 reiserfs_read_unlock_xattr_i(dentry->d_inode);
1125 return err;
1126 }
1127
1128 /* This is the implementation for the xattr plugin infrastructure */
1129 static struct list_head xattr_handlers = LIST_HEAD_INIT(xattr_handlers);
1130 static DEFINE_RWLOCK(handler_lock);
1131
1132 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char
1133 *prefix)
1134 {
1135 struct reiserfs_xattr_handler *xah = NULL;
1136 struct list_head *p;
1137
1138 read_lock(&handler_lock);
1139 list_for_each(p, &xattr_handlers) {
1140 xah = list_entry(p, struct reiserfs_xattr_handler, handlers);
1141 if (strncmp(xah->prefix, prefix, strlen(xah->prefix)) == 0)
1142 break;
1143 xah = NULL;
1144 }
1145
1146 read_unlock(&handler_lock);
1147 return xah;
1148 }
1149
1150 static void __unregister_handlers(void)
1151 {
1152 struct reiserfs_xattr_handler *xah;
1153 struct list_head *p, *tmp;
1154
1155 list_for_each_safe(p, tmp, &xattr_handlers) {
1156 xah = list_entry(p, struct reiserfs_xattr_handler, handlers);
1157 if (xah->exit)
1158 xah->exit();
1159
1160 list_del_init(p);
1161 }
1162 INIT_LIST_HEAD(&xattr_handlers);
1163 }
1164
1165 int __init reiserfs_xattr_register_handlers(void)
1166 {
1167 int err = 0;
1168 struct reiserfs_xattr_handler *xah;
1169 struct list_head *p;
1170
1171 write_lock(&handler_lock);
1172
1173 /* If we're already initialized, nothing to do */
1174 if (!list_empty(&xattr_handlers)) {
1175 write_unlock(&handler_lock);
1176 return 0;
1177 }
1178
1179 /* Add the handlers */
1180 list_add_tail(&user_handler.handlers, &xattr_handlers);
1181 list_add_tail(&trusted_handler.handlers, &xattr_handlers);
1182 #ifdef CONFIG_REISERFS_FS_SECURITY
1183 list_add_tail(&security_handler.handlers, &xattr_handlers);
1184 #endif
1185 #ifdef CONFIG_REISERFS_FS_POSIX_ACL
1186 list_add_tail(&posix_acl_access_handler.handlers, &xattr_handlers);
1187 list_add_tail(&posix_acl_default_handler.handlers, &xattr_handlers);
1188 #endif
1189
1190 /* Run initializers, if available */
1191 list_for_each(p, &xattr_handlers) {
1192 xah = list_entry(p, struct reiserfs_xattr_handler, handlers);
1193 if (xah->init) {
1194 err = xah->init();
1195 if (err) {
1196 list_del_init(p);
1197 break;
1198 }
1199 }
1200 }
1201
1202 /* Clean up other handlers, if any failed */
1203 if (err)
1204 __unregister_handlers();
1205
1206 write_unlock(&handler_lock);
1207 return err;
1208 }
1209
1210 void reiserfs_xattr_unregister_handlers(void)
1211 {
1212 write_lock(&handler_lock);
1213 __unregister_handlers();
1214 write_unlock(&handler_lock);
1215 }
1216
1217 /* This will catch lookups from the fs root to .reiserfs_priv */
1218 static int
1219 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name)
1220 {
1221 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root;
1222 if (name->len == priv_root->d_name.len &&
1223 name->hash == priv_root->d_name.hash &&
1224 !memcmp(name->name, priv_root->d_name.name, name->len)) {
1225 return -ENOENT;
1226 } else if (q1->len == name->len &&
1227 !memcmp(q1->name, name->name, name->len))
1228 return 0;
1229 return 1;
1230 }
1231
1232 static struct dentry_operations xattr_lookup_poison_ops = {
1233 .d_compare = xattr_lookup_poison,
1234 };
1235
1236 /* We need to take a copy of the mount flags since things like
1237 * MS_RDONLY don't get set until *after* we're called.
1238 * mount_flags != mount_options */
1239 int reiserfs_xattr_init(struct super_block *s, int mount_flags)
1240 {
1241 int err = 0;
1242
1243 /* We need generation numbers to ensure that the oid mapping is correct
1244 * v3.5 filesystems don't have them. */
1245 if (!old_format_only(s)) {
1246 set_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt));
1247 } else if (reiserfs_xattrs_optional(s)) {
1248 /* Old format filesystem, but optional xattrs have been enabled
1249 * at mount time. Error out. */
1250 reiserfs_warning(s, "xattrs/ACLs not supported on pre v3.6 "
1251 "format filesystem. Failing mount.");
1252 err = -EOPNOTSUPP;
1253 goto error;
1254 } else {
1255 /* Old format filesystem, but no optional xattrs have been enabled. This
1256 * means we silently disable xattrs on the filesystem. */
1257 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt));
1258 }
1259
1260 /* If we don't have the privroot located yet - go find it */
1261 if (reiserfs_xattrs(s) && !REISERFS_SB(s)->priv_root) {
1262 struct dentry *dentry;
1263 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
1264 strlen(PRIVROOT_NAME));
1265 if (!IS_ERR(dentry)) {
1266 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) {
1267 struct inode *inode = dentry->d_parent->d_inode;
1268 mutex_lock(&inode->i_mutex);
1269 err = inode->i_op->mkdir(inode, dentry, 0700);
1270 mutex_unlock(&inode->i_mutex);
1271 if (err) {
1272 dput(dentry);
1273 dentry = NULL;
1274 }
1275
1276 if (dentry && dentry->d_inode)
1277 reiserfs_warning(s,
1278 "Created %s on %s - reserved for "
1279 "xattr storage.",
1280 PRIVROOT_NAME,
1281 reiserfs_bdevname
1282 (inode->i_sb));
1283 } else if (!dentry->d_inode) {
1284 dput(dentry);
1285 dentry = NULL;
1286 }
1287 } else
1288 err = PTR_ERR(dentry);
1289
1290 if (!err && dentry) {
1291 s->s_root->d_op = &xattr_lookup_poison_ops;
1292 reiserfs_mark_inode_private(dentry->d_inode);
1293 REISERFS_SB(s)->priv_root = dentry;
1294 } else if (!(mount_flags & MS_RDONLY)) { /* xattrs are unavailable */
1295 /* If we're read-only it just means that the dir hasn't been
1296 * created. Not an error -- just no xattrs on the fs. We'll
1297 * check again if we go read-write */
1298 reiserfs_warning(s, "xattrs/ACLs enabled and couldn't "
1299 "find/create .reiserfs_priv. Failing mount.");
1300 err = -EOPNOTSUPP;
1301 }
1302 }
1303
1304 error:
1305 /* This is only nonzero if there was an error initializing the xattr
1306 * directory or if there is a condition where we don't support them. */
1307 if (err) {
1308 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt));
1309 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt));
1310 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt));
1311 }
1312
1313 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */
1314 s->s_flags = s->s_flags & ~MS_POSIXACL;
1315 if (reiserfs_posixacl(s))
1316 s->s_flags |= MS_POSIXACL;
1317
1318 return err;
1319 }
1320
1321 static int reiserfs_check_acl(struct inode *inode, int mask)
1322 {
1323 struct posix_acl *acl;
1324 int error = -EAGAIN; /* do regular unix permission checks by default */
1325
1326 reiserfs_read_lock_xattr_i(inode);
1327 reiserfs_read_lock_xattrs(inode->i_sb);
1328
1329 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
1330
1331 reiserfs_read_unlock_xattrs(inode->i_sb);
1332 reiserfs_read_unlock_xattr_i(inode);
1333
1334 if (acl) {
1335 if (!IS_ERR(acl)) {
1336 error = posix_acl_permission(inode, acl, mask);
1337 posix_acl_release(acl);
1338 } else if (PTR_ERR(acl) != -ENODATA)
1339 error = PTR_ERR(acl);
1340 }
1341
1342 return error;
1343 }
1344
1345 int reiserfs_permission(struct inode *inode, int mask, struct nameidata *nd)
1346 {
1347 /*
1348 * We don't do permission checks on the internal objects.
1349 * Permissions are determined by the "owning" object.
1350 */
1351 if (is_reiserfs_priv_object(inode))
1352 return 0;
1353
1354 /*
1355 * Stat data v1 doesn't support ACLs.
1356 */
1357 if (get_inode_sd_version(inode) == STAT_DATA_V1)
1358 return generic_permission(inode, mask, NULL);
1359 else
1360 return generic_permission(inode, mask, reiserfs_check_acl);
1361 }
Linux kernel - Deliverables
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