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