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Linux/fs/reiserfs/xattr.c

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

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