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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/reiserfs/xattr.c
4 *
5 * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com>
6 *
7 */
8
9/*
10 * In order to implement EA/ACLs in a clean, backwards compatible manner,
11 * they are implemented as files in a "private" directory.
12 * Each EA is in it's own file, with the directory layout like so (/ is assumed
13 * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory,
14 * directories named using the capital-hex form of the objectid and
15 * generation number are used. Inside each directory are individual files
16 * named with the name of the extended attribute.
17 *
18 * So, for objectid 12648430, we could have:
19 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access
20 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default
21 * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type
22 * .. or similar.
23 *
24 * The file contents are the text of the EA. The size is known based on the
25 * stat data describing the file.
26 *
27 * In the case of system.posix_acl_access and system.posix_acl_default, since
28 * these are special cases for filesystem ACLs, they are interpreted by the
29 * kernel, in addition, they are negatively and positively cached and attached
30 * to the inode so that unnecessary lookups are avoided.
31 *
32 * Locking works like so:
33 * Directory components (xattr root, xattr dir) are protectd by their i_mutex.
34 * The xattrs themselves are protected by the xattr_sem.
35 */
36
37#include "reiserfs.h"
38#include <linux/capability.h>
39#include <linux/dcache.h>
40#include <linux/namei.h>
41#include <linux/errno.h>
42#include <linux/gfp.h>
43#include <linux/fs.h>
44#include <linux/file.h>
45#include <linux/pagemap.h>
46#include <linux/xattr.h>
47#include "xattr.h"
48#include "acl.h"
49#include <linux/uaccess.h>
50#include <net/checksum.h>
51#include <linux/stat.h>
52#include <linux/quotaops.h>
53#include <linux/security.h>
54#include <linux/posix_acl_xattr.h>
55#include <linux/xattr.h>
56
57#define PRIVROOT_NAME ".reiserfs_priv"
58#define XAROOT_NAME "xattrs"
59
60
61/*
62 * Helpers for inode ops. We do this so that we don't have all the VFS
63 * overhead and also for proper i_mutex annotation.
64 * dir->i_mutex must be held for all of them.
65 */
66#ifdef CONFIG_REISERFS_FS_XATTR
67static int xattr_create(struct inode *dir, struct dentry *dentry, int mode)
68{
69 BUG_ON(!inode_is_locked(dir));
70 return dir->i_op->create(&nop_mnt_idmap, dir, dentry, mode, true);
71}
72#endif
73
74static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
75{
76 BUG_ON(!inode_is_locked(dir));
77 return dir->i_op->mkdir(&nop_mnt_idmap, dir, dentry, mode);
78}
79
80/*
81 * We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr
82 * mutation ops aren't called during rename or splace, which are the
83 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's
84 * better than allocating another subclass just for this code.
85 */
86static int xattr_unlink(struct inode *dir, struct dentry *dentry)
87{
88 int error;
89
90 BUG_ON(!inode_is_locked(dir));
91
92 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
93 error = dir->i_op->unlink(dir, dentry);
94 inode_unlock(d_inode(dentry));
95
96 if (!error)
97 d_delete(dentry);
98 return error;
99}
100
101static int xattr_rmdir(struct inode *dir, struct dentry *dentry)
102{
103 int error;
104
105 BUG_ON(!inode_is_locked(dir));
106
107 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
108 error = dir->i_op->rmdir(dir, dentry);
109 if (!error)
110 d_inode(dentry)->i_flags |= S_DEAD;
111 inode_unlock(d_inode(dentry));
112 if (!error)
113 d_delete(dentry);
114
115 return error;
116}
117
118#define xattr_may_create(flags) (!flags || flags & XATTR_CREATE)
119
120static struct dentry *open_xa_root(struct super_block *sb, int flags)
121{
122 struct dentry *privroot = REISERFS_SB(sb)->priv_root;
123 struct dentry *xaroot;
124
125 if (d_really_is_negative(privroot))
126 return ERR_PTR(-EOPNOTSUPP);
127
128 inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR);
129
130 xaroot = dget(REISERFS_SB(sb)->xattr_root);
131 if (!xaroot)
132 xaroot = ERR_PTR(-EOPNOTSUPP);
133 else if (d_really_is_negative(xaroot)) {
134 int err = -ENODATA;
135
136 if (xattr_may_create(flags))
137 err = xattr_mkdir(d_inode(privroot), xaroot, 0700);
138 if (err) {
139 dput(xaroot);
140 xaroot = ERR_PTR(err);
141 }
142 }
143
144 inode_unlock(d_inode(privroot));
145 return xaroot;
146}
147
148static struct dentry *open_xa_dir(const struct inode *inode, int flags)
149{
150 struct dentry *xaroot, *xadir;
151 char namebuf[17];
152
153 xaroot = open_xa_root(inode->i_sb, flags);
154 if (IS_ERR(xaroot))
155 return xaroot;
156
157 snprintf(namebuf, sizeof(namebuf), "%X.%X",
158 le32_to_cpu(INODE_PKEY(inode)->k_objectid),
159 inode->i_generation);
160
161 inode_lock_nested(d_inode(xaroot), I_MUTEX_XATTR);
162
163 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
164 if (!IS_ERR(xadir) && d_really_is_negative(xadir)) {
165 int err = -ENODATA;
166
167 if (xattr_may_create(flags))
168 err = xattr_mkdir(d_inode(xaroot), xadir, 0700);
169 if (err) {
170 dput(xadir);
171 xadir = ERR_PTR(err);
172 }
173 }
174
175 inode_unlock(d_inode(xaroot));
176 dput(xaroot);
177 return xadir;
178}
179
180/*
181 * The following are side effects of other operations that aren't explicitly
182 * modifying extended attributes. This includes operations such as permissions
183 * or ownership changes, object deletions, etc.
184 */
185struct reiserfs_dentry_buf {
186 struct dir_context ctx;
187 struct dentry *xadir;
188 int count;
189 int err;
190 struct dentry *dentries[8];
191};
192
193static bool
194fill_with_dentries(struct dir_context *ctx, const char *name, int namelen,
195 loff_t offset, u64 ino, unsigned int d_type)
196{
197 struct reiserfs_dentry_buf *dbuf =
198 container_of(ctx, struct reiserfs_dentry_buf, ctx);
199 struct dentry *dentry;
200
201 WARN_ON_ONCE(!inode_is_locked(d_inode(dbuf->xadir)));
202
203 if (dbuf->count == ARRAY_SIZE(dbuf->dentries))
204 return false;
205
206 if (name[0] == '.' && (namelen < 2 ||
207 (namelen == 2 && name[1] == '.')))
208 return true;
209
210 dentry = lookup_one_len(name, dbuf->xadir, namelen);
211 if (IS_ERR(dentry)) {
212 dbuf->err = PTR_ERR(dentry);
213 return false;
214 } else if (d_really_is_negative(dentry)) {
215 /* A directory entry exists, but no file? */
216 reiserfs_error(dentry->d_sb, "xattr-20003",
217 "Corrupted directory: xattr %pd listed but "
218 "not found for file %pd.\n",
219 dentry, dbuf->xadir);
220 dput(dentry);
221 dbuf->err = -EIO;
222 return false;
223 }
224
225 dbuf->dentries[dbuf->count++] = dentry;
226 return true;
227}
228
229static void
230cleanup_dentry_buf(struct reiserfs_dentry_buf *buf)
231{
232 int i;
233
234 for (i = 0; i < buf->count; i++)
235 if (buf->dentries[i])
236 dput(buf->dentries[i]);
237}
238
239static int reiserfs_for_each_xattr(struct inode *inode,
240 int (*action)(struct dentry *, void *),
241 void *data)
242{
243 struct dentry *dir;
244 int i, err = 0;
245 struct reiserfs_dentry_buf buf = {
246 .ctx.actor = fill_with_dentries,
247 };
248
249 /* Skip out, an xattr has no xattrs associated with it */
250 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1)
251 return 0;
252
253 dir = open_xa_dir(inode, XATTR_REPLACE);
254 if (IS_ERR(dir)) {
255 err = PTR_ERR(dir);
256 goto out;
257 } else if (d_really_is_negative(dir)) {
258 err = 0;
259 goto out_dir;
260 }
261
262 inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
263
264 buf.xadir = dir;
265 while (1) {
266 err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
267 if (err)
268 break;
269 if (buf.err) {
270 err = buf.err;
271 break;
272 }
273 if (!buf.count)
274 break;
275 for (i = 0; !err && i < buf.count && buf.dentries[i]; i++) {
276 struct dentry *dentry = buf.dentries[i];
277
278 if (!d_is_dir(dentry))
279 err = action(dentry, data);
280
281 dput(dentry);
282 buf.dentries[i] = NULL;
283 }
284 if (err)
285 break;
286 buf.count = 0;
287 }
288 inode_unlock(d_inode(dir));
289
290 cleanup_dentry_buf(&buf);
291
292 if (!err) {
293 /*
294 * We start a transaction here to avoid a ABBA situation
295 * between the xattr root's i_mutex and the journal lock.
296 * This doesn't incur much additional overhead since the
297 * new transaction will just nest inside the
298 * outer transaction.
299 */
300 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 +
301 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb);
302 struct reiserfs_transaction_handle th;
303
304 reiserfs_write_lock(inode->i_sb);
305 err = journal_begin(&th, inode->i_sb, blocks);
306 reiserfs_write_unlock(inode->i_sb);
307 if (!err) {
308 int jerror;
309
310 inode_lock_nested(d_inode(dir->d_parent),
311 I_MUTEX_XATTR);
312 err = action(dir, data);
313 reiserfs_write_lock(inode->i_sb);
314 jerror = journal_end(&th);
315 reiserfs_write_unlock(inode->i_sb);
316 inode_unlock(d_inode(dir->d_parent));
317 err = jerror ?: err;
318 }
319 }
320out_dir:
321 dput(dir);
322out:
323 /*
324 * -ENODATA: this object doesn't have any xattrs
325 * -EOPNOTSUPP: this file system doesn't have xattrs enabled on disk.
326 * Neither are errors
327 */
328 if (err == -ENODATA || err == -EOPNOTSUPP)
329 err = 0;
330 return err;
331}
332
333static int delete_one_xattr(struct dentry *dentry, void *data)
334{
335 struct inode *dir = d_inode(dentry->d_parent);
336
337 /* This is the xattr dir, handle specially. */
338 if (d_is_dir(dentry))
339 return xattr_rmdir(dir, dentry);
340
341 return xattr_unlink(dir, dentry);
342}
343
344static int chown_one_xattr(struct dentry *dentry, void *data)
345{
346 struct iattr *attrs = data;
347 int ia_valid = attrs->ia_valid;
348 int err;
349
350 /*
351 * We only want the ownership bits. Otherwise, we'll do
352 * things like change a directory to a regular file if
353 * ATTR_MODE is set.
354 */
355 attrs->ia_valid &= (ATTR_UID|ATTR_GID);
356 err = reiserfs_setattr(&nop_mnt_idmap, dentry, attrs);
357 attrs->ia_valid = ia_valid;
358
359 return err;
360}
361
362/* No i_mutex, but the inode is unconnected. */
363int reiserfs_delete_xattrs(struct inode *inode)
364{
365 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL);
366
367 if (err)
368 reiserfs_warning(inode->i_sb, "jdm-20004",
369 "Couldn't delete all xattrs (%d)\n", err);
370 return err;
371}
372
373/* inode->i_mutex: down */
374int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
375{
376 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs);
377
378 if (err)
379 reiserfs_warning(inode->i_sb, "jdm-20007",
380 "Couldn't chown all xattrs (%d)\n", err);
381 return err;
382}
383
384#ifdef CONFIG_REISERFS_FS_XATTR
385/*
386 * Returns a dentry corresponding to a specific extended attribute file
387 * for the inode. If flags allow, the file is created. Otherwise, a
388 * valid or negative dentry, or an error is returned.
389 */
390static struct dentry *xattr_lookup(struct inode *inode, const char *name,
391 int flags)
392{
393 struct dentry *xadir, *xafile;
394 int err = 0;
395
396 xadir = open_xa_dir(inode, flags);
397 if (IS_ERR(xadir))
398 return ERR_CAST(xadir);
399
400 inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
401 xafile = lookup_one_len(name, xadir, strlen(name));
402 if (IS_ERR(xafile)) {
403 err = PTR_ERR(xafile);
404 goto out;
405 }
406
407 if (d_really_is_positive(xafile) && (flags & XATTR_CREATE))
408 err = -EEXIST;
409
410 if (d_really_is_negative(xafile)) {
411 err = -ENODATA;
412 if (xattr_may_create(flags))
413 err = xattr_create(d_inode(xadir), xafile,
414 0700|S_IFREG);
415 }
416
417 if (err)
418 dput(xafile);
419out:
420 inode_unlock(d_inode(xadir));
421 dput(xadir);
422 if (err)
423 return ERR_PTR(err);
424 return xafile;
425}
426
427/* Internal operations on file data */
428static inline void reiserfs_put_page(struct page *page)
429{
430 kunmap(page);
431 put_page(page);
432}
433
434static struct page *reiserfs_get_page(struct inode *dir, size_t n)
435{
436 struct address_space *mapping = dir->i_mapping;
437 struct page *page;
438 /*
439 * We can deadlock if we try to free dentries,
440 * and an unlink/rmdir has just occurred - GFP_NOFS avoids this
441 */
442 mapping_set_gfp_mask(mapping, GFP_NOFS);
443 page = read_mapping_page(mapping, n >> PAGE_SHIFT, NULL);
444 if (!IS_ERR(page))
445 kmap(page);
446 return page;
447}
448
449static inline __u32 xattr_hash(const char *msg, int len)
450{
451 /*
452 * csum_partial() gives different results for little-endian and
453 * big endian hosts. Images created on little-endian hosts and
454 * mounted on big-endian hosts(and vice versa) will see csum mismatches
455 * when trying to fetch xattrs. Treating the hash as __wsum_t would
456 * lower the frequency of mismatch. This is an endianness bug in
457 * reiserfs. The return statement would result in a sparse warning. Do
458 * not fix the sparse warning so as to not hide a reminder of the bug.
459 */
460 return csum_partial(msg, len, 0);
461}
462
463int reiserfs_commit_write(struct file *f, struct page *page,
464 unsigned from, unsigned to);
465
466static void update_ctime(struct inode *inode)
467{
468 struct timespec64 now = current_time(inode);
469 struct timespec64 ctime = inode_get_ctime(inode);
470
471 if (inode_unhashed(inode) || !inode->i_nlink ||
472 timespec64_equal(&ctime, &now))
473 return;
474
475 inode_set_ctime_to_ts(inode, now);
476 mark_inode_dirty(inode);
477}
478
479static int lookup_and_delete_xattr(struct inode *inode, const char *name)
480{
481 int err = 0;
482 struct dentry *dentry, *xadir;
483
484 xadir = open_xa_dir(inode, XATTR_REPLACE);
485 if (IS_ERR(xadir))
486 return PTR_ERR(xadir);
487
488 inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
489 dentry = lookup_one_len(name, xadir, strlen(name));
490 if (IS_ERR(dentry)) {
491 err = PTR_ERR(dentry);
492 goto out_dput;
493 }
494
495 if (d_really_is_positive(dentry)) {
496 err = xattr_unlink(d_inode(xadir), dentry);
497 update_ctime(inode);
498 }
499
500 dput(dentry);
501out_dput:
502 inode_unlock(d_inode(xadir));
503 dput(xadir);
504 return err;
505}
506
507
508/* Generic extended attribute operations that can be used by xa plugins */
509
510/*
511 * inode->i_mutex: down
512 */
513int
514reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th,
515 struct inode *inode, const char *name,
516 const void *buffer, size_t buffer_size, int flags)
517{
518 int err = 0;
519 struct dentry *dentry;
520 struct page *page;
521 char *data;
522 size_t file_pos = 0;
523 size_t buffer_pos = 0;
524 size_t new_size;
525 __u32 xahash = 0;
526
527 if (get_inode_sd_version(inode) == STAT_DATA_V1)
528 return -EOPNOTSUPP;
529
530 if (!buffer) {
531 err = lookup_and_delete_xattr(inode, name);
532 return err;
533 }
534
535 dentry = xattr_lookup(inode, name, flags);
536 if (IS_ERR(dentry))
537 return PTR_ERR(dentry);
538
539 down_write(&REISERFS_I(inode)->i_xattr_sem);
540
541 xahash = xattr_hash(buffer, buffer_size);
542 while (buffer_pos < buffer_size || buffer_pos == 0) {
543 size_t chunk;
544 size_t skip = 0;
545 size_t page_offset = (file_pos & (PAGE_SIZE - 1));
546
547 if (buffer_size - buffer_pos > PAGE_SIZE)
548 chunk = PAGE_SIZE;
549 else
550 chunk = buffer_size - buffer_pos;
551
552 page = reiserfs_get_page(d_inode(dentry), file_pos);
553 if (IS_ERR(page)) {
554 err = PTR_ERR(page);
555 goto out_unlock;
556 }
557
558 lock_page(page);
559 data = page_address(page);
560
561 if (file_pos == 0) {
562 struct reiserfs_xattr_header *rxh;
563
564 skip = file_pos = sizeof(struct reiserfs_xattr_header);
565 if (chunk + skip > PAGE_SIZE)
566 chunk = PAGE_SIZE - skip;
567 rxh = (struct reiserfs_xattr_header *)data;
568 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC);
569 rxh->h_hash = cpu_to_le32(xahash);
570 }
571
572 reiserfs_write_lock(inode->i_sb);
573 err = __reiserfs_write_begin(page, page_offset, chunk + skip);
574 if (!err) {
575 if (buffer)
576 memcpy(data + skip, buffer + buffer_pos, chunk);
577 err = reiserfs_commit_write(NULL, page, page_offset,
578 page_offset + chunk +
579 skip);
580 }
581 reiserfs_write_unlock(inode->i_sb);
582 unlock_page(page);
583 reiserfs_put_page(page);
584 buffer_pos += chunk;
585 file_pos += chunk;
586 skip = 0;
587 if (err || buffer_size == 0 || !buffer)
588 break;
589 }
590
591 new_size = buffer_size + sizeof(struct reiserfs_xattr_header);
592 if (!err && new_size < i_size_read(d_inode(dentry))) {
593 struct iattr newattrs = {
594 .ia_ctime = current_time(inode),
595 .ia_size = new_size,
596 .ia_valid = ATTR_SIZE | ATTR_CTIME,
597 };
598
599 inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR);
600 inode_dio_wait(d_inode(dentry));
601
602 err = reiserfs_setattr(&nop_mnt_idmap, dentry, &newattrs);
603 inode_unlock(d_inode(dentry));
604 } else
605 update_ctime(inode);
606out_unlock:
607 up_write(&REISERFS_I(inode)->i_xattr_sem);
608 dput(dentry);
609 return err;
610}
611
612/* We need to start a transaction to maintain lock ordering */
613int reiserfs_xattr_set(struct inode *inode, const char *name,
614 const void *buffer, size_t buffer_size, int flags)
615{
616
617 struct reiserfs_transaction_handle th;
618 int error, error2;
619 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size);
620
621 /* Check before we start a transaction and then do nothing. */
622 if (!d_really_is_positive(REISERFS_SB(inode->i_sb)->priv_root))
623 return -EOPNOTSUPP;
624
625 if (!(flags & XATTR_REPLACE))
626 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode);
627
628 reiserfs_write_lock(inode->i_sb);
629 error = journal_begin(&th, inode->i_sb, jbegin_count);
630 reiserfs_write_unlock(inode->i_sb);
631 if (error) {
632 return error;
633 }
634
635 error = reiserfs_xattr_set_handle(&th, inode, name,
636 buffer, buffer_size, flags);
637
638 reiserfs_write_lock(inode->i_sb);
639 error2 = journal_end(&th);
640 reiserfs_write_unlock(inode->i_sb);
641 if (error == 0)
642 error = error2;
643
644 return error;
645}
646
647/*
648 * inode->i_mutex: down
649 */
650int
651reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer,
652 size_t buffer_size)
653{
654 ssize_t err = 0;
655 struct dentry *dentry;
656 size_t isize;
657 size_t file_pos = 0;
658 size_t buffer_pos = 0;
659 struct page *page;
660 __u32 hash = 0;
661
662 if (name == NULL)
663 return -EINVAL;
664
665 /*
666 * We can't have xattrs attached to v1 items since they don't have
667 * generation numbers
668 */
669 if (get_inode_sd_version(inode) == STAT_DATA_V1)
670 return -EOPNOTSUPP;
671
672 /*
673 * priv_root needn't be initialized during mount so allow initial
674 * lookups to succeed.
675 */
676 if (!REISERFS_SB(inode->i_sb)->priv_root)
677 return 0;
678
679 dentry = xattr_lookup(inode, name, XATTR_REPLACE);
680 if (IS_ERR(dentry)) {
681 err = PTR_ERR(dentry);
682 goto out;
683 }
684
685 down_read(&REISERFS_I(inode)->i_xattr_sem);
686
687 isize = i_size_read(d_inode(dentry));
688
689 /* Just return the size needed */
690 if (buffer == NULL) {
691 err = isize - sizeof(struct reiserfs_xattr_header);
692 goto out_unlock;
693 }
694
695 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) {
696 err = -ERANGE;
697 goto out_unlock;
698 }
699
700 while (file_pos < isize) {
701 size_t chunk;
702 char *data;
703 size_t skip = 0;
704
705 if (isize - file_pos > PAGE_SIZE)
706 chunk = PAGE_SIZE;
707 else
708 chunk = isize - file_pos;
709
710 page = reiserfs_get_page(d_inode(dentry), file_pos);
711 if (IS_ERR(page)) {
712 err = PTR_ERR(page);
713 goto out_unlock;
714 }
715
716 lock_page(page);
717 data = page_address(page);
718 if (file_pos == 0) {
719 struct reiserfs_xattr_header *rxh =
720 (struct reiserfs_xattr_header *)data;
721 skip = file_pos = sizeof(struct reiserfs_xattr_header);
722 chunk -= skip;
723 /* Magic doesn't match up.. */
724 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) {
725 unlock_page(page);
726 reiserfs_put_page(page);
727 reiserfs_warning(inode->i_sb, "jdm-20001",
728 "Invalid magic for xattr (%s) "
729 "associated with %k", name,
730 INODE_PKEY(inode));
731 err = -EIO;
732 goto out_unlock;
733 }
734 hash = le32_to_cpu(rxh->h_hash);
735 }
736 memcpy(buffer + buffer_pos, data + skip, chunk);
737 unlock_page(page);
738 reiserfs_put_page(page);
739 file_pos += chunk;
740 buffer_pos += chunk;
741 skip = 0;
742 }
743 err = isize - sizeof(struct reiserfs_xattr_header);
744
745 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) !=
746 hash) {
747 reiserfs_warning(inode->i_sb, "jdm-20002",
748 "Invalid hash for xattr (%s) associated "
749 "with %k", name, INODE_PKEY(inode));
750 err = -EIO;
751 }
752
753out_unlock:
754 up_read(&REISERFS_I(inode)->i_xattr_sem);
755 dput(dentry);
756
757out:
758 return err;
759}
760
761/*
762 * In order to implement different sets of xattr operations for each xattr
763 * prefix with the generic xattr API, a filesystem should create a
764 * null-terminated array of struct xattr_handler (one for each prefix) and
765 * hang a pointer to it off of the s_xattr field of the superblock.
766 *
767 * The generic_fooxattr() functions will use this list to dispatch xattr
768 * operations to the correct xattr_handler.
769 */
770#define for_each_xattr_handler(handlers, handler) \
771 for ((handler) = *(handlers)++; \
772 (handler) != NULL; \
773 (handler) = *(handlers)++)
774
775static inline bool reiserfs_posix_acl_list(const char *name,
776 struct dentry *dentry)
777{
778 return (posix_acl_type(name) >= 0) &&
779 IS_POSIXACL(d_backing_inode(dentry));
780}
781
782/* This is the implementation for the xattr plugin infrastructure */
783static inline bool reiserfs_xattr_list(const struct xattr_handler * const *handlers,
784 const char *name, struct dentry *dentry)
785{
786 if (handlers) {
787 const struct xattr_handler *xah = NULL;
788
789 for_each_xattr_handler(handlers, xah) {
790 const char *prefix = xattr_prefix(xah);
791
792 if (strncmp(prefix, name, strlen(prefix)))
793 continue;
794
795 if (!xattr_handler_can_list(xah, dentry))
796 return false;
797
798 return true;
799 }
800 }
801
802 return reiserfs_posix_acl_list(name, dentry);
803}
804
805struct listxattr_buf {
806 struct dir_context ctx;
807 size_t size;
808 size_t pos;
809 char *buf;
810 struct dentry *dentry;
811};
812
813static bool listxattr_filler(struct dir_context *ctx, const char *name,
814 int namelen, loff_t offset, u64 ino,
815 unsigned int d_type)
816{
817 struct listxattr_buf *b =
818 container_of(ctx, struct listxattr_buf, ctx);
819 size_t size;
820
821 if (name[0] != '.' ||
822 (namelen != 1 && (name[1] != '.' || namelen != 2))) {
823 if (!reiserfs_xattr_list(b->dentry->d_sb->s_xattr, name,
824 b->dentry))
825 return true;
826 size = namelen + 1;
827 if (b->buf) {
828 if (b->pos + size > b->size) {
829 b->pos = -ERANGE;
830 return false;
831 }
832 memcpy(b->buf + b->pos, name, namelen);
833 b->buf[b->pos + namelen] = 0;
834 }
835 b->pos += size;
836 }
837 return true;
838}
839
840/*
841 * Inode operation listxattr()
842 *
843 * We totally ignore the generic listxattr here because it would be stupid
844 * not to. Since the xattrs are organized in a directory, we can just
845 * readdir to find them.
846 */
847ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
848{
849 struct dentry *dir;
850 int err = 0;
851 struct listxattr_buf buf = {
852 .ctx.actor = listxattr_filler,
853 .dentry = dentry,
854 .buf = buffer,
855 .size = buffer ? size : 0,
856 };
857
858 if (d_really_is_negative(dentry))
859 return -EINVAL;
860
861 if (get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1)
862 return -EOPNOTSUPP;
863
864 dir = open_xa_dir(d_inode(dentry), XATTR_REPLACE);
865 if (IS_ERR(dir)) {
866 err = PTR_ERR(dir);
867 if (err == -ENODATA)
868 err = 0; /* Not an error if there aren't any xattrs */
869 goto out;
870 }
871
872 inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
873 err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
874 inode_unlock(d_inode(dir));
875
876 if (!err)
877 err = buf.pos;
878
879 dput(dir);
880out:
881 return err;
882}
883
884static int create_privroot(struct dentry *dentry)
885{
886 int err;
887 struct inode *inode = d_inode(dentry->d_parent);
888
889 WARN_ON_ONCE(!inode_is_locked(inode));
890
891 err = xattr_mkdir(inode, dentry, 0700);
892 if (err || d_really_is_negative(dentry)) {
893 reiserfs_warning(dentry->d_sb, "jdm-20006",
894 "xattrs/ACLs enabled and couldn't "
895 "find/create .reiserfs_priv. "
896 "Failing mount.");
897 return -EOPNOTSUPP;
898 }
899
900 reiserfs_init_priv_inode(d_inode(dentry));
901 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr "
902 "storage.\n", PRIVROOT_NAME);
903
904 return 0;
905}
906
907#else
908int __init reiserfs_xattr_register_handlers(void) { return 0; }
909void reiserfs_xattr_unregister_handlers(void) {}
910static int create_privroot(struct dentry *dentry) { return 0; }
911#endif
912
913/* Actual operations that are exported to VFS-land */
914const struct xattr_handler * const reiserfs_xattr_handlers[] = {
915#ifdef CONFIG_REISERFS_FS_XATTR
916 &reiserfs_xattr_user_handler,
917 &reiserfs_xattr_trusted_handler,
918#endif
919#ifdef CONFIG_REISERFS_FS_SECURITY
920 &reiserfs_xattr_security_handler,
921#endif
922 NULL
923};
924
925static int xattr_mount_check(struct super_block *s)
926{
927 /*
928 * We need generation numbers to ensure that the oid mapping is correct
929 * v3.5 filesystems don't have them.
930 */
931 if (old_format_only(s)) {
932 if (reiserfs_xattrs_optional(s)) {
933 /*
934 * Old format filesystem, but optional xattrs have
935 * been enabled. Error out.
936 */
937 reiserfs_warning(s, "jdm-2005",
938 "xattrs/ACLs not supported "
939 "on pre-v3.6 format filesystems. "
940 "Failing mount.");
941 return -EOPNOTSUPP;
942 }
943 }
944
945 return 0;
946}
947
948int reiserfs_permission(struct mnt_idmap *idmap, struct inode *inode,
949 int mask)
950{
951 /*
952 * We don't do permission checks on the internal objects.
953 * Permissions are determined by the "owning" object.
954 */
955 if (IS_PRIVATE(inode))
956 return 0;
957
958 return generic_permission(&nop_mnt_idmap, inode, mask);
959}
960
961static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags)
962{
963 return -EPERM;
964}
965
966static const struct dentry_operations xattr_lookup_poison_ops = {
967 .d_revalidate = xattr_hide_revalidate,
968};
969
970int reiserfs_lookup_privroot(struct super_block *s)
971{
972 struct dentry *dentry;
973 int err = 0;
974
975 /* If we don't have the privroot located yet - go find it */
976 inode_lock(d_inode(s->s_root));
977 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
978 strlen(PRIVROOT_NAME));
979 if (!IS_ERR(dentry)) {
980 REISERFS_SB(s)->priv_root = dentry;
981 d_set_d_op(dentry, &xattr_lookup_poison_ops);
982 if (d_really_is_positive(dentry))
983 reiserfs_init_priv_inode(d_inode(dentry));
984 } else
985 err = PTR_ERR(dentry);
986 inode_unlock(d_inode(s->s_root));
987
988 return err;
989}
990
991/*
992 * We need to take a copy of the mount flags since things like
993 * SB_RDONLY don't get set until *after* we're called.
994 * mount_flags != mount_options
995 */
996int reiserfs_xattr_init(struct super_block *s, int mount_flags)
997{
998 int err = 0;
999 struct dentry *privroot = REISERFS_SB(s)->priv_root;
1000
1001 err = xattr_mount_check(s);
1002 if (err)
1003 goto error;
1004
1005 if (d_really_is_negative(privroot) && !(mount_flags & SB_RDONLY)) {
1006 inode_lock(d_inode(s->s_root));
1007 err = create_privroot(REISERFS_SB(s)->priv_root);
1008 inode_unlock(d_inode(s->s_root));
1009 }
1010
1011 if (d_really_is_positive(privroot)) {
1012 inode_lock(d_inode(privroot));
1013 if (!REISERFS_SB(s)->xattr_root) {
1014 struct dentry *dentry;
1015
1016 dentry = lookup_one_len(XAROOT_NAME, privroot,
1017 strlen(XAROOT_NAME));
1018 if (!IS_ERR(dentry))
1019 REISERFS_SB(s)->xattr_root = dentry;
1020 else
1021 err = PTR_ERR(dentry);
1022 }
1023 inode_unlock(d_inode(privroot));
1024 }
1025
1026error:
1027 if (err) {
1028 clear_bit(REISERFS_XATTRS_USER, &REISERFS_SB(s)->s_mount_opt);
1029 clear_bit(REISERFS_POSIXACL, &REISERFS_SB(s)->s_mount_opt);
1030 }
1031
1032 /* The super_block SB_POSIXACL must mirror the (no)acl mount option. */
1033 if (reiserfs_posixacl(s))
1034 s->s_flags |= SB_POSIXACL;
1035 else
1036 s->s_flags &= ~SB_POSIXACL;
1037
1038 return err;
1039}
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 * Locking works like so:
32 * Directory components (xattr root, xattr dir) are protectd by their i_mutex.
33 * The xattrs themselves are protected by the xattr_sem.
34 */
35
36#include "reiserfs.h"
37#include <linux/capability.h>
38#include <linux/dcache.h>
39#include <linux/namei.h>
40#include <linux/errno.h>
41#include <linux/gfp.h>
42#include <linux/fs.h>
43#include <linux/file.h>
44#include <linux/pagemap.h>
45#include <linux/xattr.h>
46#include "xattr.h"
47#include "acl.h"
48#include <linux/uaccess.h>
49#include <net/checksum.h>
50#include <linux/stat.h>
51#include <linux/quotaops.h>
52#include <linux/security.h>
53#include <linux/posix_acl_xattr.h>
54
55#define PRIVROOT_NAME ".reiserfs_priv"
56#define XAROOT_NAME "xattrs"
57
58
59/*
60 * Helpers for inode ops. We do this so that we don't have all the VFS
61 * overhead and also for proper i_mutex annotation.
62 * dir->i_mutex must be held for all of them.
63 */
64#ifdef CONFIG_REISERFS_FS_XATTR
65static int xattr_create(struct inode *dir, struct dentry *dentry, int mode)
66{
67 BUG_ON(!inode_is_locked(dir));
68 return dir->i_op->create(dir, dentry, mode, true);
69}
70#endif
71
72static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
73{
74 BUG_ON(!inode_is_locked(dir));
75 return dir->i_op->mkdir(dir, dentry, mode);
76}
77
78/*
79 * We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr
80 * mutation ops aren't called during rename or splace, which are the
81 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's
82 * better than allocating another subclass just for this code.
83 */
84static int xattr_unlink(struct inode *dir, struct dentry *dentry)
85{
86 int error;
87
88 BUG_ON(!inode_is_locked(dir));
89
90 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
91 error = dir->i_op->unlink(dir, dentry);
92 inode_unlock(d_inode(dentry));
93
94 if (!error)
95 d_delete(dentry);
96 return error;
97}
98
99static int xattr_rmdir(struct inode *dir, struct dentry *dentry)
100{
101 int error;
102
103 BUG_ON(!inode_is_locked(dir));
104
105 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
106 error = dir->i_op->rmdir(dir, dentry);
107 if (!error)
108 d_inode(dentry)->i_flags |= S_DEAD;
109 inode_unlock(d_inode(dentry));
110 if (!error)
111 d_delete(dentry);
112
113 return error;
114}
115
116#define xattr_may_create(flags) (!flags || flags & XATTR_CREATE)
117
118static struct dentry *open_xa_root(struct super_block *sb, int flags)
119{
120 struct dentry *privroot = REISERFS_SB(sb)->priv_root;
121 struct dentry *xaroot;
122
123 if (d_really_is_negative(privroot))
124 return ERR_PTR(-ENODATA);
125
126 inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR);
127
128 xaroot = dget(REISERFS_SB(sb)->xattr_root);
129 if (!xaroot)
130 xaroot = ERR_PTR(-ENODATA);
131 else if (d_really_is_negative(xaroot)) {
132 int err = -ENODATA;
133
134 if (xattr_may_create(flags))
135 err = xattr_mkdir(d_inode(privroot), xaroot, 0700);
136 if (err) {
137 dput(xaroot);
138 xaroot = ERR_PTR(err);
139 }
140 }
141
142 inode_unlock(d_inode(privroot));
143 return xaroot;
144}
145
146static struct dentry *open_xa_dir(const struct inode *inode, int flags)
147{
148 struct dentry *xaroot, *xadir;
149 char namebuf[17];
150
151 xaroot = open_xa_root(inode->i_sb, flags);
152 if (IS_ERR(xaroot))
153 return xaroot;
154
155 snprintf(namebuf, sizeof(namebuf), "%X.%X",
156 le32_to_cpu(INODE_PKEY(inode)->k_objectid),
157 inode->i_generation);
158
159 inode_lock_nested(d_inode(xaroot), I_MUTEX_XATTR);
160
161 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
162 if (!IS_ERR(xadir) && d_really_is_negative(xadir)) {
163 int err = -ENODATA;
164
165 if (xattr_may_create(flags))
166 err = xattr_mkdir(d_inode(xaroot), xadir, 0700);
167 if (err) {
168 dput(xadir);
169 xadir = ERR_PTR(err);
170 }
171 }
172
173 inode_unlock(d_inode(xaroot));
174 dput(xaroot);
175 return xadir;
176}
177
178/*
179 * The following are side effects of other operations that aren't explicitly
180 * modifying extended attributes. This includes operations such as permissions
181 * or ownership changes, object deletions, etc.
182 */
183struct reiserfs_dentry_buf {
184 struct dir_context ctx;
185 struct dentry *xadir;
186 int count;
187 struct dentry *dentries[8];
188};
189
190static int
191fill_with_dentries(struct dir_context *ctx, const char *name, int namelen,
192 loff_t offset, u64 ino, unsigned int d_type)
193{
194 struct reiserfs_dentry_buf *dbuf =
195 container_of(ctx, struct reiserfs_dentry_buf, ctx);
196 struct dentry *dentry;
197
198 WARN_ON_ONCE(!inode_is_locked(d_inode(dbuf->xadir)));
199
200 if (dbuf->count == ARRAY_SIZE(dbuf->dentries))
201 return -ENOSPC;
202
203 if (name[0] == '.' && (namelen < 2 ||
204 (namelen == 2 && name[1] == '.')))
205 return 0;
206
207 dentry = lookup_one_len(name, dbuf->xadir, namelen);
208 if (IS_ERR(dentry)) {
209 return PTR_ERR(dentry);
210 } else if (d_really_is_negative(dentry)) {
211 /* A directory entry exists, but no file? */
212 reiserfs_error(dentry->d_sb, "xattr-20003",
213 "Corrupted directory: xattr %pd listed but "
214 "not found for file %pd.\n",
215 dentry, dbuf->xadir);
216 dput(dentry);
217 return -EIO;
218 }
219
220 dbuf->dentries[dbuf->count++] = dentry;
221 return 0;
222}
223
224static void
225cleanup_dentry_buf(struct reiserfs_dentry_buf *buf)
226{
227 int i;
228
229 for (i = 0; i < buf->count; i++)
230 if (buf->dentries[i])
231 dput(buf->dentries[i]);
232}
233
234static int reiserfs_for_each_xattr(struct inode *inode,
235 int (*action)(struct dentry *, void *),
236 void *data)
237{
238 struct dentry *dir;
239 int i, err = 0;
240 struct reiserfs_dentry_buf buf = {
241 .ctx.actor = fill_with_dentries,
242 };
243
244 /* Skip out, an xattr has no xattrs associated with it */
245 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1)
246 return 0;
247
248 dir = open_xa_dir(inode, XATTR_REPLACE);
249 if (IS_ERR(dir)) {
250 err = PTR_ERR(dir);
251 goto out;
252 } else if (d_really_is_negative(dir)) {
253 err = 0;
254 goto out_dir;
255 }
256
257 inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
258
259 buf.xadir = dir;
260 while (1) {
261 err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
262 if (err)
263 break;
264 if (!buf.count)
265 break;
266 for (i = 0; !err && i < buf.count && buf.dentries[i]; i++) {
267 struct dentry *dentry = buf.dentries[i];
268
269 if (!d_is_dir(dentry))
270 err = action(dentry, data);
271
272 dput(dentry);
273 buf.dentries[i] = NULL;
274 }
275 if (err)
276 break;
277 buf.count = 0;
278 }
279 inode_unlock(d_inode(dir));
280
281 cleanup_dentry_buf(&buf);
282
283 if (!err) {
284 /*
285 * We start a transaction here to avoid a ABBA situation
286 * between the xattr root's i_mutex and the journal lock.
287 * This doesn't incur much additional overhead since the
288 * new transaction will just nest inside the
289 * outer transaction.
290 */
291 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 +
292 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb);
293 struct reiserfs_transaction_handle th;
294
295 reiserfs_write_lock(inode->i_sb);
296 err = journal_begin(&th, inode->i_sb, blocks);
297 reiserfs_write_unlock(inode->i_sb);
298 if (!err) {
299 int jerror;
300
301 inode_lock_nested(d_inode(dir->d_parent),
302 I_MUTEX_XATTR);
303 err = action(dir, data);
304 reiserfs_write_lock(inode->i_sb);
305 jerror = journal_end(&th);
306 reiserfs_write_unlock(inode->i_sb);
307 inode_unlock(d_inode(dir->d_parent));
308 err = jerror ?: err;
309 }
310 }
311out_dir:
312 dput(dir);
313out:
314 /* -ENODATA isn't an error */
315 if (err == -ENODATA)
316 err = 0;
317 return err;
318}
319
320static int delete_one_xattr(struct dentry *dentry, void *data)
321{
322 struct inode *dir = d_inode(dentry->d_parent);
323
324 /* This is the xattr dir, handle specially. */
325 if (d_is_dir(dentry))
326 return xattr_rmdir(dir, dentry);
327
328 return xattr_unlink(dir, dentry);
329}
330
331static int chown_one_xattr(struct dentry *dentry, void *data)
332{
333 struct iattr *attrs = data;
334 int ia_valid = attrs->ia_valid;
335 int err;
336
337 /*
338 * We only want the ownership bits. Otherwise, we'll do
339 * things like change a directory to a regular file if
340 * ATTR_MODE is set.
341 */
342 attrs->ia_valid &= (ATTR_UID|ATTR_GID);
343 err = reiserfs_setattr(dentry, attrs);
344 attrs->ia_valid = ia_valid;
345
346 return err;
347}
348
349/* No i_mutex, but the inode is unconnected. */
350int reiserfs_delete_xattrs(struct inode *inode)
351{
352 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL);
353
354 if (err)
355 reiserfs_warning(inode->i_sb, "jdm-20004",
356 "Couldn't delete all xattrs (%d)\n", err);
357 return err;
358}
359
360/* inode->i_mutex: down */
361int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
362{
363 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs);
364
365 if (err)
366 reiserfs_warning(inode->i_sb, "jdm-20007",
367 "Couldn't chown all xattrs (%d)\n", err);
368 return err;
369}
370
371#ifdef CONFIG_REISERFS_FS_XATTR
372/*
373 * Returns a dentry corresponding to a specific extended attribute file
374 * for the inode. If flags allow, the file is created. Otherwise, a
375 * valid or negative dentry, or an error is returned.
376 */
377static struct dentry *xattr_lookup(struct inode *inode, const char *name,
378 int flags)
379{
380 struct dentry *xadir, *xafile;
381 int err = 0;
382
383 xadir = open_xa_dir(inode, flags);
384 if (IS_ERR(xadir))
385 return ERR_CAST(xadir);
386
387 inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
388 xafile = lookup_one_len(name, xadir, strlen(name));
389 if (IS_ERR(xafile)) {
390 err = PTR_ERR(xafile);
391 goto out;
392 }
393
394 if (d_really_is_positive(xafile) && (flags & XATTR_CREATE))
395 err = -EEXIST;
396
397 if (d_really_is_negative(xafile)) {
398 err = -ENODATA;
399 if (xattr_may_create(flags))
400 err = xattr_create(d_inode(xadir), xafile,
401 0700|S_IFREG);
402 }
403
404 if (err)
405 dput(xafile);
406out:
407 inode_unlock(d_inode(xadir));
408 dput(xadir);
409 if (err)
410 return ERR_PTR(err);
411 return xafile;
412}
413
414/* Internal operations on file data */
415static inline void reiserfs_put_page(struct page *page)
416{
417 kunmap(page);
418 put_page(page);
419}
420
421static struct page *reiserfs_get_page(struct inode *dir, size_t n)
422{
423 struct address_space *mapping = dir->i_mapping;
424 struct page *page;
425 /*
426 * We can deadlock if we try to free dentries,
427 * and an unlink/rmdir has just occurred - GFP_NOFS avoids this
428 */
429 mapping_set_gfp_mask(mapping, GFP_NOFS);
430 page = read_mapping_page(mapping, n >> PAGE_SHIFT, NULL);
431 if (!IS_ERR(page)) {
432 kmap(page);
433 if (PageError(page))
434 goto fail;
435 }
436 return page;
437
438fail:
439 reiserfs_put_page(page);
440 return ERR_PTR(-EIO);
441}
442
443static inline __u32 xattr_hash(const char *msg, int len)
444{
445 return csum_partial(msg, len, 0);
446}
447
448int reiserfs_commit_write(struct file *f, struct page *page,
449 unsigned from, unsigned to);
450
451static void update_ctime(struct inode *inode)
452{
453 struct timespec now = current_fs_time(inode->i_sb);
454
455 if (inode_unhashed(inode) || !inode->i_nlink ||
456 timespec_equal(&inode->i_ctime, &now))
457 return;
458
459 inode->i_ctime = CURRENT_TIME_SEC;
460 mark_inode_dirty(inode);
461}
462
463static int lookup_and_delete_xattr(struct inode *inode, const char *name)
464{
465 int err = 0;
466 struct dentry *dentry, *xadir;
467
468 xadir = open_xa_dir(inode, XATTR_REPLACE);
469 if (IS_ERR(xadir))
470 return PTR_ERR(xadir);
471
472 inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
473 dentry = lookup_one_len(name, xadir, strlen(name));
474 if (IS_ERR(dentry)) {
475 err = PTR_ERR(dentry);
476 goto out_dput;
477 }
478
479 if (d_really_is_positive(dentry)) {
480 err = xattr_unlink(d_inode(xadir), dentry);
481 update_ctime(inode);
482 }
483
484 dput(dentry);
485out_dput:
486 inode_unlock(d_inode(xadir));
487 dput(xadir);
488 return err;
489}
490
491
492/* Generic extended attribute operations that can be used by xa plugins */
493
494/*
495 * inode->i_mutex: down
496 */
497int
498reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th,
499 struct inode *inode, const char *name,
500 const void *buffer, size_t buffer_size, int flags)
501{
502 int err = 0;
503 struct dentry *dentry;
504 struct page *page;
505 char *data;
506 size_t file_pos = 0;
507 size_t buffer_pos = 0;
508 size_t new_size;
509 __u32 xahash = 0;
510
511 if (get_inode_sd_version(inode) == STAT_DATA_V1)
512 return -EOPNOTSUPP;
513
514 if (!buffer) {
515 err = lookup_and_delete_xattr(inode, name);
516 return err;
517 }
518
519 dentry = xattr_lookup(inode, name, flags);
520 if (IS_ERR(dentry))
521 return PTR_ERR(dentry);
522
523 down_write(&REISERFS_I(inode)->i_xattr_sem);
524
525 xahash = xattr_hash(buffer, buffer_size);
526 while (buffer_pos < buffer_size || buffer_pos == 0) {
527 size_t chunk;
528 size_t skip = 0;
529 size_t page_offset = (file_pos & (PAGE_SIZE - 1));
530
531 if (buffer_size - buffer_pos > PAGE_SIZE)
532 chunk = PAGE_SIZE;
533 else
534 chunk = buffer_size - buffer_pos;
535
536 page = reiserfs_get_page(d_inode(dentry), file_pos);
537 if (IS_ERR(page)) {
538 err = PTR_ERR(page);
539 goto out_unlock;
540 }
541
542 lock_page(page);
543 data = page_address(page);
544
545 if (file_pos == 0) {
546 struct reiserfs_xattr_header *rxh;
547
548 skip = file_pos = sizeof(struct reiserfs_xattr_header);
549 if (chunk + skip > PAGE_SIZE)
550 chunk = PAGE_SIZE - skip;
551 rxh = (struct reiserfs_xattr_header *)data;
552 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC);
553 rxh->h_hash = cpu_to_le32(xahash);
554 }
555
556 reiserfs_write_lock(inode->i_sb);
557 err = __reiserfs_write_begin(page, page_offset, chunk + skip);
558 if (!err) {
559 if (buffer)
560 memcpy(data + skip, buffer + buffer_pos, chunk);
561 err = reiserfs_commit_write(NULL, page, page_offset,
562 page_offset + chunk +
563 skip);
564 }
565 reiserfs_write_unlock(inode->i_sb);
566 unlock_page(page);
567 reiserfs_put_page(page);
568 buffer_pos += chunk;
569 file_pos += chunk;
570 skip = 0;
571 if (err || buffer_size == 0 || !buffer)
572 break;
573 }
574
575 new_size = buffer_size + sizeof(struct reiserfs_xattr_header);
576 if (!err && new_size < i_size_read(d_inode(dentry))) {
577 struct iattr newattrs = {
578 .ia_ctime = current_fs_time(inode->i_sb),
579 .ia_size = new_size,
580 .ia_valid = ATTR_SIZE | ATTR_CTIME,
581 };
582
583 inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR);
584 inode_dio_wait(d_inode(dentry));
585
586 err = reiserfs_setattr(dentry, &newattrs);
587 inode_unlock(d_inode(dentry));
588 } else
589 update_ctime(inode);
590out_unlock:
591 up_write(&REISERFS_I(inode)->i_xattr_sem);
592 dput(dentry);
593 return err;
594}
595
596/* We need to start a transaction to maintain lock ordering */
597int reiserfs_xattr_set(struct inode *inode, const char *name,
598 const void *buffer, size_t buffer_size, int flags)
599{
600
601 struct reiserfs_transaction_handle th;
602 int error, error2;
603 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size);
604
605 if (!(flags & XATTR_REPLACE))
606 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode);
607
608 reiserfs_write_lock(inode->i_sb);
609 error = journal_begin(&th, inode->i_sb, jbegin_count);
610 reiserfs_write_unlock(inode->i_sb);
611 if (error) {
612 return error;
613 }
614
615 error = reiserfs_xattr_set_handle(&th, inode, name,
616 buffer, buffer_size, flags);
617
618 reiserfs_write_lock(inode->i_sb);
619 error2 = journal_end(&th);
620 reiserfs_write_unlock(inode->i_sb);
621 if (error == 0)
622 error = error2;
623
624 return error;
625}
626
627/*
628 * inode->i_mutex: down
629 */
630int
631reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer,
632 size_t buffer_size)
633{
634 ssize_t err = 0;
635 struct dentry *dentry;
636 size_t isize;
637 size_t file_pos = 0;
638 size_t buffer_pos = 0;
639 struct page *page;
640 __u32 hash = 0;
641
642 if (name == NULL)
643 return -EINVAL;
644
645 /*
646 * We can't have xattrs attached to v1 items since they don't have
647 * generation numbers
648 */
649 if (get_inode_sd_version(inode) == STAT_DATA_V1)
650 return -EOPNOTSUPP;
651
652 dentry = xattr_lookup(inode, name, XATTR_REPLACE);
653 if (IS_ERR(dentry)) {
654 err = PTR_ERR(dentry);
655 goto out;
656 }
657
658 down_read(&REISERFS_I(inode)->i_xattr_sem);
659
660 isize = i_size_read(d_inode(dentry));
661
662 /* Just return the size needed */
663 if (buffer == NULL) {
664 err = isize - sizeof(struct reiserfs_xattr_header);
665 goto out_unlock;
666 }
667
668 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) {
669 err = -ERANGE;
670 goto out_unlock;
671 }
672
673 while (file_pos < isize) {
674 size_t chunk;
675 char *data;
676 size_t skip = 0;
677
678 if (isize - file_pos > PAGE_SIZE)
679 chunk = PAGE_SIZE;
680 else
681 chunk = isize - file_pos;
682
683 page = reiserfs_get_page(d_inode(dentry), file_pos);
684 if (IS_ERR(page)) {
685 err = PTR_ERR(page);
686 goto out_unlock;
687 }
688
689 lock_page(page);
690 data = page_address(page);
691 if (file_pos == 0) {
692 struct reiserfs_xattr_header *rxh =
693 (struct reiserfs_xattr_header *)data;
694 skip = file_pos = sizeof(struct reiserfs_xattr_header);
695 chunk -= skip;
696 /* Magic doesn't match up.. */
697 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) {
698 unlock_page(page);
699 reiserfs_put_page(page);
700 reiserfs_warning(inode->i_sb, "jdm-20001",
701 "Invalid magic for xattr (%s) "
702 "associated with %k", name,
703 INODE_PKEY(inode));
704 err = -EIO;
705 goto out_unlock;
706 }
707 hash = le32_to_cpu(rxh->h_hash);
708 }
709 memcpy(buffer + buffer_pos, data + skip, chunk);
710 unlock_page(page);
711 reiserfs_put_page(page);
712 file_pos += chunk;
713 buffer_pos += chunk;
714 skip = 0;
715 }
716 err = isize - sizeof(struct reiserfs_xattr_header);
717
718 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) !=
719 hash) {
720 reiserfs_warning(inode->i_sb, "jdm-20002",
721 "Invalid hash for xattr (%s) associated "
722 "with %k", name, INODE_PKEY(inode));
723 err = -EIO;
724 }
725
726out_unlock:
727 up_read(&REISERFS_I(inode)->i_xattr_sem);
728 dput(dentry);
729
730out:
731 return err;
732}
733
734/*
735 * In order to implement different sets of xattr operations for each xattr
736 * prefix with the generic xattr API, a filesystem should create a
737 * null-terminated array of struct xattr_handler (one for each prefix) and
738 * hang a pointer to it off of the s_xattr field of the superblock.
739 *
740 * The generic_fooxattr() functions will use this list to dispatch xattr
741 * operations to the correct xattr_handler.
742 */
743#define for_each_xattr_handler(handlers, handler) \
744 for ((handler) = *(handlers)++; \
745 (handler) != NULL; \
746 (handler) = *(handlers)++)
747
748/* This is the implementation for the xattr plugin infrastructure */
749static inline const struct xattr_handler *
750find_xattr_handler_prefix(const struct xattr_handler **handlers,
751 const char *name)
752{
753 const struct xattr_handler *xah;
754
755 if (!handlers)
756 return NULL;
757
758 for_each_xattr_handler(handlers, xah) {
759 const char *prefix = xattr_prefix(xah);
760 if (strncmp(prefix, name, strlen(prefix)) == 0)
761 break;
762 }
763
764 return xah;
765}
766
767
768/*
769 * Inode operation getxattr()
770 */
771ssize_t
772reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer,
773 size_t size)
774{
775 const struct xattr_handler *handler;
776
777 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name);
778
779 if (!handler || get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1)
780 return -EOPNOTSUPP;
781
782 return handler->get(handler, dentry, name, buffer, size);
783}
784
785/*
786 * Inode operation setxattr()
787 *
788 * d_inode(dentry)->i_mutex down
789 */
790int
791reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value,
792 size_t size, int flags)
793{
794 const struct xattr_handler *handler;
795
796 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name);
797
798 if (!handler || get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1)
799 return -EOPNOTSUPP;
800
801 return handler->set(handler, dentry, name, value, size, flags);
802}
803
804/*
805 * Inode operation removexattr()
806 *
807 * d_inode(dentry)->i_mutex down
808 */
809int reiserfs_removexattr(struct dentry *dentry, const char *name)
810{
811 const struct xattr_handler *handler;
812
813 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name);
814
815 if (!handler || get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1)
816 return -EOPNOTSUPP;
817
818 return handler->set(handler, dentry, name, NULL, 0, XATTR_REPLACE);
819}
820
821struct listxattr_buf {
822 struct dir_context ctx;
823 size_t size;
824 size_t pos;
825 char *buf;
826 struct dentry *dentry;
827};
828
829static int listxattr_filler(struct dir_context *ctx, const char *name,
830 int namelen, loff_t offset, u64 ino,
831 unsigned int d_type)
832{
833 struct listxattr_buf *b =
834 container_of(ctx, struct listxattr_buf, ctx);
835 size_t size;
836
837 if (name[0] != '.' ||
838 (namelen != 1 && (name[1] != '.' || namelen != 2))) {
839 const struct xattr_handler *handler;
840
841 handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr,
842 name);
843 if (!handler /* Unsupported xattr name */ ||
844 (handler->list && !handler->list(b->dentry)))
845 return 0;
846 size = namelen + 1;
847 if (b->buf) {
848 if (size > b->size)
849 return -ERANGE;
850 memcpy(b->buf + b->pos, name, namelen);
851 b->buf[b->pos + namelen] = 0;
852 }
853 b->pos += size;
854 }
855 return 0;
856}
857
858/*
859 * Inode operation listxattr()
860 *
861 * We totally ignore the generic listxattr here because it would be stupid
862 * not to. Since the xattrs are organized in a directory, we can just
863 * readdir to find them.
864 */
865ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
866{
867 struct dentry *dir;
868 int err = 0;
869 struct listxattr_buf buf = {
870 .ctx.actor = listxattr_filler,
871 .dentry = dentry,
872 .buf = buffer,
873 .size = buffer ? size : 0,
874 };
875
876 if (d_really_is_negative(dentry))
877 return -EINVAL;
878
879 if (!dentry->d_sb->s_xattr ||
880 get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1)
881 return -EOPNOTSUPP;
882
883 dir = open_xa_dir(d_inode(dentry), XATTR_REPLACE);
884 if (IS_ERR(dir)) {
885 err = PTR_ERR(dir);
886 if (err == -ENODATA)
887 err = 0; /* Not an error if there aren't any xattrs */
888 goto out;
889 }
890
891 inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
892 err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
893 inode_unlock(d_inode(dir));
894
895 if (!err)
896 err = buf.pos;
897
898 dput(dir);
899out:
900 return err;
901}
902
903static int create_privroot(struct dentry *dentry)
904{
905 int err;
906 struct inode *inode = d_inode(dentry->d_parent);
907
908 WARN_ON_ONCE(!inode_is_locked(inode));
909
910 err = xattr_mkdir(inode, dentry, 0700);
911 if (err || d_really_is_negative(dentry)) {
912 reiserfs_warning(dentry->d_sb, "jdm-20006",
913 "xattrs/ACLs enabled and couldn't "
914 "find/create .reiserfs_priv. "
915 "Failing mount.");
916 return -EOPNOTSUPP;
917 }
918
919 d_inode(dentry)->i_flags |= S_PRIVATE;
920 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr "
921 "storage.\n", PRIVROOT_NAME);
922
923 return 0;
924}
925
926#else
927int __init reiserfs_xattr_register_handlers(void) { return 0; }
928void reiserfs_xattr_unregister_handlers(void) {}
929static int create_privroot(struct dentry *dentry) { return 0; }
930#endif
931
932/* Actual operations that are exported to VFS-land */
933static const struct xattr_handler *reiserfs_xattr_handlers[] = {
934#ifdef CONFIG_REISERFS_FS_XATTR
935 &reiserfs_xattr_user_handler,
936 &reiserfs_xattr_trusted_handler,
937#endif
938#ifdef CONFIG_REISERFS_FS_SECURITY
939 &reiserfs_xattr_security_handler,
940#endif
941#ifdef CONFIG_REISERFS_FS_POSIX_ACL
942 &posix_acl_access_xattr_handler,
943 &posix_acl_default_xattr_handler,
944#endif
945 NULL
946};
947
948static int xattr_mount_check(struct super_block *s)
949{
950 /*
951 * We need generation numbers to ensure that the oid mapping is correct
952 * v3.5 filesystems don't have them.
953 */
954 if (old_format_only(s)) {
955 if (reiserfs_xattrs_optional(s)) {
956 /*
957 * Old format filesystem, but optional xattrs have
958 * been enabled. Error out.
959 */
960 reiserfs_warning(s, "jdm-2005",
961 "xattrs/ACLs not supported "
962 "on pre-v3.6 format filesystems. "
963 "Failing mount.");
964 return -EOPNOTSUPP;
965 }
966 }
967
968 return 0;
969}
970
971int reiserfs_permission(struct inode *inode, int mask)
972{
973 /*
974 * We don't do permission checks on the internal objects.
975 * Permissions are determined by the "owning" object.
976 */
977 if (IS_PRIVATE(inode))
978 return 0;
979
980 return generic_permission(inode, mask);
981}
982
983static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags)
984{
985 return -EPERM;
986}
987
988static const struct dentry_operations xattr_lookup_poison_ops = {
989 .d_revalidate = xattr_hide_revalidate,
990};
991
992int reiserfs_lookup_privroot(struct super_block *s)
993{
994 struct dentry *dentry;
995 int err = 0;
996
997 /* If we don't have the privroot located yet - go find it */
998 inode_lock(d_inode(s->s_root));
999 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
1000 strlen(PRIVROOT_NAME));
1001 if (!IS_ERR(dentry)) {
1002 REISERFS_SB(s)->priv_root = dentry;
1003 d_set_d_op(dentry, &xattr_lookup_poison_ops);
1004 if (d_really_is_positive(dentry))
1005 d_inode(dentry)->i_flags |= S_PRIVATE;
1006 } else
1007 err = PTR_ERR(dentry);
1008 inode_unlock(d_inode(s->s_root));
1009
1010 return err;
1011}
1012
1013/*
1014 * We need to take a copy of the mount flags since things like
1015 * MS_RDONLY don't get set until *after* we're called.
1016 * mount_flags != mount_options
1017 */
1018int reiserfs_xattr_init(struct super_block *s, int mount_flags)
1019{
1020 int err = 0;
1021 struct dentry *privroot = REISERFS_SB(s)->priv_root;
1022
1023 err = xattr_mount_check(s);
1024 if (err)
1025 goto error;
1026
1027 if (d_really_is_negative(privroot) && !(mount_flags & MS_RDONLY)) {
1028 inode_lock(d_inode(s->s_root));
1029 err = create_privroot(REISERFS_SB(s)->priv_root);
1030 inode_unlock(d_inode(s->s_root));
1031 }
1032
1033 if (d_really_is_positive(privroot)) {
1034 s->s_xattr = reiserfs_xattr_handlers;
1035 inode_lock(d_inode(privroot));
1036 if (!REISERFS_SB(s)->xattr_root) {
1037 struct dentry *dentry;
1038
1039 dentry = lookup_one_len(XAROOT_NAME, privroot,
1040 strlen(XAROOT_NAME));
1041 if (!IS_ERR(dentry))
1042 REISERFS_SB(s)->xattr_root = dentry;
1043 else
1044 err = PTR_ERR(dentry);
1045 }
1046 inode_unlock(d_inode(privroot));
1047 }
1048
1049error:
1050 if (err) {
1051 clear_bit(REISERFS_XATTRS_USER, &REISERFS_SB(s)->s_mount_opt);
1052 clear_bit(REISERFS_POSIXACL, &REISERFS_SB(s)->s_mount_opt);
1053 }
1054
1055 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */
1056 if (reiserfs_posixacl(s))
1057 s->s_flags |= MS_POSIXACL;
1058 else
1059 s->s_flags &= ~MS_POSIXACL;
1060
1061 return err;
1062}