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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}
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(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(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(-ENODATA);
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(-ENODATA);
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 int
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 -ENOSPC;
204
205 if (name[0] == '.' && (namelen < 2 ||
206 (namelen == 2 && name[1] == '.')))
207 return 0;
208
209 dentry = lookup_one_len(name, dbuf->xadir, namelen);
210 if (IS_ERR(dentry)) {
211 dbuf->err = PTR_ERR(dentry);
212 return PTR_ERR(dentry);
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 -EIO;
222 }
223
224 dbuf->dentries[dbuf->count++] = dentry;
225 return 0;
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 /* -ENODATA isn't an error */
323 if (err == -ENODATA)
324 err = 0;
325 return err;
326}
327
328static int delete_one_xattr(struct dentry *dentry, void *data)
329{
330 struct inode *dir = d_inode(dentry->d_parent);
331
332 /* This is the xattr dir, handle specially. */
333 if (d_is_dir(dentry))
334 return xattr_rmdir(dir, dentry);
335
336 return xattr_unlink(dir, dentry);
337}
338
339static int chown_one_xattr(struct dentry *dentry, void *data)
340{
341 struct iattr *attrs = data;
342 int ia_valid = attrs->ia_valid;
343 int err;
344
345 /*
346 * We only want the ownership bits. Otherwise, we'll do
347 * things like change a directory to a regular file if
348 * ATTR_MODE is set.
349 */
350 attrs->ia_valid &= (ATTR_UID|ATTR_GID);
351 err = reiserfs_setattr(dentry, attrs);
352 attrs->ia_valid = ia_valid;
353
354 return err;
355}
356
357/* No i_mutex, but the inode is unconnected. */
358int reiserfs_delete_xattrs(struct inode *inode)
359{
360 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL);
361
362 if (err)
363 reiserfs_warning(inode->i_sb, "jdm-20004",
364 "Couldn't delete all xattrs (%d)\n", err);
365 return err;
366}
367
368/* inode->i_mutex: down */
369int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
370{
371 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs);
372
373 if (err)
374 reiserfs_warning(inode->i_sb, "jdm-20007",
375 "Couldn't chown all xattrs (%d)\n", err);
376 return err;
377}
378
379#ifdef CONFIG_REISERFS_FS_XATTR
380/*
381 * Returns a dentry corresponding to a specific extended attribute file
382 * for the inode. If flags allow, the file is created. Otherwise, a
383 * valid or negative dentry, or an error is returned.
384 */
385static struct dentry *xattr_lookup(struct inode *inode, const char *name,
386 int flags)
387{
388 struct dentry *xadir, *xafile;
389 int err = 0;
390
391 xadir = open_xa_dir(inode, flags);
392 if (IS_ERR(xadir))
393 return ERR_CAST(xadir);
394
395 inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
396 xafile = lookup_one_len(name, xadir, strlen(name));
397 if (IS_ERR(xafile)) {
398 err = PTR_ERR(xafile);
399 goto out;
400 }
401
402 if (d_really_is_positive(xafile) && (flags & XATTR_CREATE))
403 err = -EEXIST;
404
405 if (d_really_is_negative(xafile)) {
406 err = -ENODATA;
407 if (xattr_may_create(flags))
408 err = xattr_create(d_inode(xadir), xafile,
409 0700|S_IFREG);
410 }
411
412 if (err)
413 dput(xafile);
414out:
415 inode_unlock(d_inode(xadir));
416 dput(xadir);
417 if (err)
418 return ERR_PTR(err);
419 return xafile;
420}
421
422/* Internal operations on file data */
423static inline void reiserfs_put_page(struct page *page)
424{
425 kunmap(page);
426 put_page(page);
427}
428
429static struct page *reiserfs_get_page(struct inode *dir, size_t n)
430{
431 struct address_space *mapping = dir->i_mapping;
432 struct page *page;
433 /*
434 * We can deadlock if we try to free dentries,
435 * and an unlink/rmdir has just occurred - GFP_NOFS avoids this
436 */
437 mapping_set_gfp_mask(mapping, GFP_NOFS);
438 page = read_mapping_page(mapping, n >> PAGE_SHIFT, NULL);
439 if (!IS_ERR(page)) {
440 kmap(page);
441 if (PageError(page))
442 goto fail;
443 }
444 return page;
445
446fail:
447 reiserfs_put_page(page);
448 return ERR_PTR(-EIO);
449}
450
451static inline __u32 xattr_hash(const char *msg, int len)
452{
453 /*
454 * csum_partial() gives different results for little-endian and
455 * big endian hosts. Images created on little-endian hosts and
456 * mounted on big-endian hosts(and vice versa) will see csum mismatches
457 * when trying to fetch xattrs. Treating the hash as __wsum_t would
458 * lower the frequency of mismatch. This is an endianness bug in
459 * reiserfs. The return statement would result in a sparse warning. Do
460 * not fix the sparse warning so as to not hide a reminder of the bug.
461 */
462 return csum_partial(msg, len, 0);
463}
464
465int reiserfs_commit_write(struct file *f, struct page *page,
466 unsigned from, unsigned to);
467
468static void update_ctime(struct inode *inode)
469{
470 struct timespec64 now = current_time(inode);
471
472 if (inode_unhashed(inode) || !inode->i_nlink ||
473 timespec64_equal(&inode->i_ctime, &now))
474 return;
475
476 inode->i_ctime = current_time(inode);
477 mark_inode_dirty(inode);
478}
479
480static int lookup_and_delete_xattr(struct inode *inode, const char *name)
481{
482 int err = 0;
483 struct dentry *dentry, *xadir;
484
485 xadir = open_xa_dir(inode, XATTR_REPLACE);
486 if (IS_ERR(xadir))
487 return PTR_ERR(xadir);
488
489 inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
490 dentry = lookup_one_len(name, xadir, strlen(name));
491 if (IS_ERR(dentry)) {
492 err = PTR_ERR(dentry);
493 goto out_dput;
494 }
495
496 if (d_really_is_positive(dentry)) {
497 err = xattr_unlink(d_inode(xadir), dentry);
498 update_ctime(inode);
499 }
500
501 dput(dentry);
502out_dput:
503 inode_unlock(d_inode(xadir));
504 dput(xadir);
505 return err;
506}
507
508
509/* Generic extended attribute operations that can be used by xa plugins */
510
511/*
512 * inode->i_mutex: down
513 */
514int
515reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th,
516 struct inode *inode, const char *name,
517 const void *buffer, size_t buffer_size, int flags)
518{
519 int err = 0;
520 struct dentry *dentry;
521 struct page *page;
522 char *data;
523 size_t file_pos = 0;
524 size_t buffer_pos = 0;
525 size_t new_size;
526 __u32 xahash = 0;
527
528 if (get_inode_sd_version(inode) == STAT_DATA_V1)
529 return -EOPNOTSUPP;
530
531 if (!buffer) {
532 err = lookup_and_delete_xattr(inode, name);
533 return err;
534 }
535
536 dentry = xattr_lookup(inode, name, flags);
537 if (IS_ERR(dentry))
538 return PTR_ERR(dentry);
539
540 down_write(&REISERFS_I(inode)->i_xattr_sem);
541
542 xahash = xattr_hash(buffer, buffer_size);
543 while (buffer_pos < buffer_size || buffer_pos == 0) {
544 size_t chunk;
545 size_t skip = 0;
546 size_t page_offset = (file_pos & (PAGE_SIZE - 1));
547
548 if (buffer_size - buffer_pos > PAGE_SIZE)
549 chunk = PAGE_SIZE;
550 else
551 chunk = buffer_size - buffer_pos;
552
553 page = reiserfs_get_page(d_inode(dentry), file_pos);
554 if (IS_ERR(page)) {
555 err = PTR_ERR(page);
556 goto out_unlock;
557 }
558
559 lock_page(page);
560 data = page_address(page);
561
562 if (file_pos == 0) {
563 struct reiserfs_xattr_header *rxh;
564
565 skip = file_pos = sizeof(struct reiserfs_xattr_header);
566 if (chunk + skip > PAGE_SIZE)
567 chunk = PAGE_SIZE - skip;
568 rxh = (struct reiserfs_xattr_header *)data;
569 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC);
570 rxh->h_hash = cpu_to_le32(xahash);
571 }
572
573 reiserfs_write_lock(inode->i_sb);
574 err = __reiserfs_write_begin(page, page_offset, chunk + skip);
575 if (!err) {
576 if (buffer)
577 memcpy(data + skip, buffer + buffer_pos, chunk);
578 err = reiserfs_commit_write(NULL, page, page_offset,
579 page_offset + chunk +
580 skip);
581 }
582 reiserfs_write_unlock(inode->i_sb);
583 unlock_page(page);
584 reiserfs_put_page(page);
585 buffer_pos += chunk;
586 file_pos += chunk;
587 skip = 0;
588 if (err || buffer_size == 0 || !buffer)
589 break;
590 }
591
592 new_size = buffer_size + sizeof(struct reiserfs_xattr_header);
593 if (!err && new_size < i_size_read(d_inode(dentry))) {
594 struct iattr newattrs = {
595 .ia_ctime = current_time(inode),
596 .ia_size = new_size,
597 .ia_valid = ATTR_SIZE | ATTR_CTIME,
598 };
599
600 inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR);
601 inode_dio_wait(d_inode(dentry));
602
603 err = reiserfs_setattr(dentry, &newattrs);
604 inode_unlock(d_inode(dentry));
605 } else
606 update_ctime(inode);
607out_unlock:
608 up_write(&REISERFS_I(inode)->i_xattr_sem);
609 dput(dentry);
610 return err;
611}
612
613/* We need to start a transaction to maintain lock ordering */
614int reiserfs_xattr_set(struct inode *inode, const char *name,
615 const void *buffer, size_t buffer_size, int flags)
616{
617
618 struct reiserfs_transaction_handle th;
619 int error, error2;
620 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size);
621
622 if (!(flags & XATTR_REPLACE))
623 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode);
624
625 reiserfs_write_lock(inode->i_sb);
626 error = journal_begin(&th, inode->i_sb, jbegin_count);
627 reiserfs_write_unlock(inode->i_sb);
628 if (error) {
629 return error;
630 }
631
632 error = reiserfs_xattr_set_handle(&th, inode, name,
633 buffer, buffer_size, flags);
634
635 reiserfs_write_lock(inode->i_sb);
636 error2 = journal_end(&th);
637 reiserfs_write_unlock(inode->i_sb);
638 if (error == 0)
639 error = error2;
640
641 return error;
642}
643
644/*
645 * inode->i_mutex: down
646 */
647int
648reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer,
649 size_t buffer_size)
650{
651 ssize_t err = 0;
652 struct dentry *dentry;
653 size_t isize;
654 size_t file_pos = 0;
655 size_t buffer_pos = 0;
656 struct page *page;
657 __u32 hash = 0;
658
659 if (name == NULL)
660 return -EINVAL;
661
662 /*
663 * We can't have xattrs attached to v1 items since they don't have
664 * generation numbers
665 */
666 if (get_inode_sd_version(inode) == STAT_DATA_V1)
667 return -EOPNOTSUPP;
668
669 dentry = xattr_lookup(inode, name, XATTR_REPLACE);
670 if (IS_ERR(dentry)) {
671 err = PTR_ERR(dentry);
672 goto out;
673 }
674
675 down_read(&REISERFS_I(inode)->i_xattr_sem);
676
677 isize = i_size_read(d_inode(dentry));
678
679 /* Just return the size needed */
680 if (buffer == NULL) {
681 err = isize - sizeof(struct reiserfs_xattr_header);
682 goto out_unlock;
683 }
684
685 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) {
686 err = -ERANGE;
687 goto out_unlock;
688 }
689
690 while (file_pos < isize) {
691 size_t chunk;
692 char *data;
693 size_t skip = 0;
694
695 if (isize - file_pos > PAGE_SIZE)
696 chunk = PAGE_SIZE;
697 else
698 chunk = isize - file_pos;
699
700 page = reiserfs_get_page(d_inode(dentry), file_pos);
701 if (IS_ERR(page)) {
702 err = PTR_ERR(page);
703 goto out_unlock;
704 }
705
706 lock_page(page);
707 data = page_address(page);
708 if (file_pos == 0) {
709 struct reiserfs_xattr_header *rxh =
710 (struct reiserfs_xattr_header *)data;
711 skip = file_pos = sizeof(struct reiserfs_xattr_header);
712 chunk -= skip;
713 /* Magic doesn't match up.. */
714 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) {
715 unlock_page(page);
716 reiserfs_put_page(page);
717 reiserfs_warning(inode->i_sb, "jdm-20001",
718 "Invalid magic for xattr (%s) "
719 "associated with %k", name,
720 INODE_PKEY(inode));
721 err = -EIO;
722 goto out_unlock;
723 }
724 hash = le32_to_cpu(rxh->h_hash);
725 }
726 memcpy(buffer + buffer_pos, data + skip, chunk);
727 unlock_page(page);
728 reiserfs_put_page(page);
729 file_pos += chunk;
730 buffer_pos += chunk;
731 skip = 0;
732 }
733 err = isize - sizeof(struct reiserfs_xattr_header);
734
735 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) !=
736 hash) {
737 reiserfs_warning(inode->i_sb, "jdm-20002",
738 "Invalid hash for xattr (%s) associated "
739 "with %k", name, INODE_PKEY(inode));
740 err = -EIO;
741 }
742
743out_unlock:
744 up_read(&REISERFS_I(inode)->i_xattr_sem);
745 dput(dentry);
746
747out:
748 return err;
749}
750
751/*
752 * In order to implement different sets of xattr operations for each xattr
753 * prefix with the generic xattr API, a filesystem should create a
754 * null-terminated array of struct xattr_handler (one for each prefix) and
755 * hang a pointer to it off of the s_xattr field of the superblock.
756 *
757 * The generic_fooxattr() functions will use this list to dispatch xattr
758 * operations to the correct xattr_handler.
759 */
760#define for_each_xattr_handler(handlers, handler) \
761 for ((handler) = *(handlers)++; \
762 (handler) != NULL; \
763 (handler) = *(handlers)++)
764
765/* This is the implementation for the xattr plugin infrastructure */
766static inline const struct xattr_handler *
767find_xattr_handler_prefix(const struct xattr_handler **handlers,
768 const char *name)
769{
770 const struct xattr_handler *xah;
771
772 if (!handlers)
773 return NULL;
774
775 for_each_xattr_handler(handlers, xah) {
776 const char *prefix = xattr_prefix(xah);
777 if (strncmp(prefix, name, strlen(prefix)) == 0)
778 break;
779 }
780
781 return xah;
782}
783
784struct listxattr_buf {
785 struct dir_context ctx;
786 size_t size;
787 size_t pos;
788 char *buf;
789 struct dentry *dentry;
790};
791
792static int listxattr_filler(struct dir_context *ctx, const char *name,
793 int namelen, loff_t offset, u64 ino,
794 unsigned int d_type)
795{
796 struct listxattr_buf *b =
797 container_of(ctx, struct listxattr_buf, ctx);
798 size_t size;
799
800 if (name[0] != '.' ||
801 (namelen != 1 && (name[1] != '.' || namelen != 2))) {
802 const struct xattr_handler *handler;
803
804 handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr,
805 name);
806 if (!handler /* Unsupported xattr name */ ||
807 (handler->list && !handler->list(b->dentry)))
808 return 0;
809 size = namelen + 1;
810 if (b->buf) {
811 if (b->pos + size > b->size) {
812 b->pos = -ERANGE;
813 return -ERANGE;
814 }
815 memcpy(b->buf + b->pos, name, namelen);
816 b->buf[b->pos + namelen] = 0;
817 }
818 b->pos += size;
819 }
820 return 0;
821}
822
823/*
824 * Inode operation listxattr()
825 *
826 * We totally ignore the generic listxattr here because it would be stupid
827 * not to. Since the xattrs are organized in a directory, we can just
828 * readdir to find them.
829 */
830ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
831{
832 struct dentry *dir;
833 int err = 0;
834 struct listxattr_buf buf = {
835 .ctx.actor = listxattr_filler,
836 .dentry = dentry,
837 .buf = buffer,
838 .size = buffer ? size : 0,
839 };
840
841 if (d_really_is_negative(dentry))
842 return -EINVAL;
843
844 if (!dentry->d_sb->s_xattr ||
845 get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1)
846 return -EOPNOTSUPP;
847
848 dir = open_xa_dir(d_inode(dentry), XATTR_REPLACE);
849 if (IS_ERR(dir)) {
850 err = PTR_ERR(dir);
851 if (err == -ENODATA)
852 err = 0; /* Not an error if there aren't any xattrs */
853 goto out;
854 }
855
856 inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
857 err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
858 inode_unlock(d_inode(dir));
859
860 if (!err)
861 err = buf.pos;
862
863 dput(dir);
864out:
865 return err;
866}
867
868static int create_privroot(struct dentry *dentry)
869{
870 int err;
871 struct inode *inode = d_inode(dentry->d_parent);
872
873 WARN_ON_ONCE(!inode_is_locked(inode));
874
875 err = xattr_mkdir(inode, dentry, 0700);
876 if (err || d_really_is_negative(dentry)) {
877 reiserfs_warning(dentry->d_sb, "jdm-20006",
878 "xattrs/ACLs enabled and couldn't "
879 "find/create .reiserfs_priv. "
880 "Failing mount.");
881 return -EOPNOTSUPP;
882 }
883
884 d_inode(dentry)->i_flags |= S_PRIVATE;
885 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr "
886 "storage.\n", PRIVROOT_NAME);
887
888 return 0;
889}
890
891#else
892int __init reiserfs_xattr_register_handlers(void) { return 0; }
893void reiserfs_xattr_unregister_handlers(void) {}
894static int create_privroot(struct dentry *dentry) { return 0; }
895#endif
896
897/* Actual operations that are exported to VFS-land */
898static const struct xattr_handler *reiserfs_xattr_handlers[] = {
899#ifdef CONFIG_REISERFS_FS_XATTR
900 &reiserfs_xattr_user_handler,
901 &reiserfs_xattr_trusted_handler,
902#endif
903#ifdef CONFIG_REISERFS_FS_SECURITY
904 &reiserfs_xattr_security_handler,
905#endif
906#ifdef CONFIG_REISERFS_FS_POSIX_ACL
907 &posix_acl_access_xattr_handler,
908 &posix_acl_default_xattr_handler,
909#endif
910 NULL
911};
912
913static int xattr_mount_check(struct super_block *s)
914{
915 /*
916 * We need generation numbers to ensure that the oid mapping is correct
917 * v3.5 filesystems don't have them.
918 */
919 if (old_format_only(s)) {
920 if (reiserfs_xattrs_optional(s)) {
921 /*
922 * Old format filesystem, but optional xattrs have
923 * been enabled. Error out.
924 */
925 reiserfs_warning(s, "jdm-2005",
926 "xattrs/ACLs not supported "
927 "on pre-v3.6 format filesystems. "
928 "Failing mount.");
929 return -EOPNOTSUPP;
930 }
931 }
932
933 return 0;
934}
935
936int reiserfs_permission(struct inode *inode, int mask)
937{
938 /*
939 * We don't do permission checks on the internal objects.
940 * Permissions are determined by the "owning" object.
941 */
942 if (IS_PRIVATE(inode))
943 return 0;
944
945 return generic_permission(inode, mask);
946}
947
948static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags)
949{
950 return -EPERM;
951}
952
953static const struct dentry_operations xattr_lookup_poison_ops = {
954 .d_revalidate = xattr_hide_revalidate,
955};
956
957int reiserfs_lookup_privroot(struct super_block *s)
958{
959 struct dentry *dentry;
960 int err = 0;
961
962 /* If we don't have the privroot located yet - go find it */
963 inode_lock(d_inode(s->s_root));
964 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
965 strlen(PRIVROOT_NAME));
966 if (!IS_ERR(dentry)) {
967 REISERFS_SB(s)->priv_root = dentry;
968 d_set_d_op(dentry, &xattr_lookup_poison_ops);
969 if (d_really_is_positive(dentry))
970 d_inode(dentry)->i_flags |= S_PRIVATE;
971 } else
972 err = PTR_ERR(dentry);
973 inode_unlock(d_inode(s->s_root));
974
975 return err;
976}
977
978/*
979 * We need to take a copy of the mount flags since things like
980 * SB_RDONLY don't get set until *after* we're called.
981 * mount_flags != mount_options
982 */
983int reiserfs_xattr_init(struct super_block *s, int mount_flags)
984{
985 int err = 0;
986 struct dentry *privroot = REISERFS_SB(s)->priv_root;
987
988 err = xattr_mount_check(s);
989 if (err)
990 goto error;
991
992 if (d_really_is_negative(privroot) && !(mount_flags & SB_RDONLY)) {
993 inode_lock(d_inode(s->s_root));
994 err = create_privroot(REISERFS_SB(s)->priv_root);
995 inode_unlock(d_inode(s->s_root));
996 }
997
998 if (d_really_is_positive(privroot)) {
999 s->s_xattr = reiserfs_xattr_handlers;
1000 inode_lock(d_inode(privroot));
1001 if (!REISERFS_SB(s)->xattr_root) {
1002 struct dentry *dentry;
1003
1004 dentry = lookup_one_len(XAROOT_NAME, privroot,
1005 strlen(XAROOT_NAME));
1006 if (!IS_ERR(dentry))
1007 REISERFS_SB(s)->xattr_root = dentry;
1008 else
1009 err = PTR_ERR(dentry);
1010 }
1011 inode_unlock(d_inode(privroot));
1012 }
1013
1014error:
1015 if (err) {
1016 clear_bit(REISERFS_XATTRS_USER, &REISERFS_SB(s)->s_mount_opt);
1017 clear_bit(REISERFS_POSIXACL, &REISERFS_SB(s)->s_mount_opt);
1018 }
1019
1020 /* The super_block SB_POSIXACL must mirror the (no)acl mount option. */
1021 if (reiserfs_posixacl(s))
1022 s->s_flags |= SB_POSIXACL;
1023 else
1024 s->s_flags &= ~SB_POSIXACL;
1025
1026 return err;
1027}