1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2011 Novell Inc.
4 * Copyright (C) 2016 Red Hat, Inc.
8 #include <linux/mount.h>
9 #include <linux/slab.h>
10 #include <linux/cred.h>
11 #include <linux/xattr.h>
12 #include <linux/exportfs.h>
13 #include <linux/uuid.h>
14 #include <linux/namei.h>
15 #include <linux/ratelimit.h>
16 #include "overlayfs.h"
18 int ovl_want_write(struct dentry *dentry)
20 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
21 return mnt_want_write(ovl_upper_mnt(ofs));
24 void ovl_drop_write(struct dentry *dentry)
26 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
27 mnt_drop_write(ovl_upper_mnt(ofs));
30 struct dentry *ovl_workdir(struct dentry *dentry)
32 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
36 const struct cred *ovl_override_creds(struct super_block *sb)
38 struct ovl_fs *ofs = sb->s_fs_info;
40 return override_creds(ofs->creator_cred);
44 * Check if underlying fs supports file handles and try to determine encoding
45 * type, in order to deduce maximum inode number used by fs.
47 * Return 0 if file handles are not supported.
48 * Return 1 (FILEID_INO32_GEN) if fs uses the default 32bit inode encoding.
49 * Return -1 if fs uses a non default encoding with unknown inode size.
51 int ovl_can_decode_fh(struct super_block *sb)
53 if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry)
56 return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN;
59 struct dentry *ovl_indexdir(struct super_block *sb)
61 struct ovl_fs *ofs = sb->s_fs_info;
66 /* Index all files on copy up. For now only enabled for NFS export */
67 bool ovl_index_all(struct super_block *sb)
69 struct ovl_fs *ofs = sb->s_fs_info;
71 return ofs->config.nfs_export && ofs->config.index;
74 /* Verify lower origin on lookup. For now only enabled for NFS export */
75 bool ovl_verify_lower(struct super_block *sb)
77 struct ovl_fs *ofs = sb->s_fs_info;
79 return ofs->config.nfs_export && ofs->config.index;
82 struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
84 size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
85 struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
88 oe->numlower = numlower;
93 #define OVL_D_REVALIDATE (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE)
95 bool ovl_dentry_remote(struct dentry *dentry)
97 return dentry->d_flags & OVL_D_REVALIDATE;
100 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry)
102 if (!ovl_dentry_remote(realdentry))
105 spin_lock(&dentry->d_lock);
106 dentry->d_flags |= realdentry->d_flags & OVL_D_REVALIDATE;
107 spin_unlock(&dentry->d_lock);
110 void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry)
112 return ovl_dentry_init_flags(dentry, upperdentry, OVL_D_REVALIDATE);
115 void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
118 struct ovl_entry *oe = OVL_E(dentry);
119 unsigned int i, flags = 0;
122 flags |= upperdentry->d_flags;
123 for (i = 0; i < oe->numlower; i++)
124 flags |= oe->lowerstack[i].dentry->d_flags;
126 spin_lock(&dentry->d_lock);
127 dentry->d_flags &= ~mask;
128 dentry->d_flags |= flags & mask;
129 spin_unlock(&dentry->d_lock);
132 bool ovl_dentry_weird(struct dentry *dentry)
134 return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
135 DCACHE_MANAGE_TRANSIT |
140 enum ovl_path_type ovl_path_type(struct dentry *dentry)
142 struct ovl_entry *oe = dentry->d_fsdata;
143 enum ovl_path_type type = 0;
145 if (ovl_dentry_upper(dentry)) {
146 type = __OVL_PATH_UPPER;
149 * Non-dir dentry can hold lower dentry of its copy up origin.
152 if (ovl_test_flag(OVL_CONST_INO, d_inode(dentry)))
153 type |= __OVL_PATH_ORIGIN;
154 if (d_is_dir(dentry) ||
155 !ovl_has_upperdata(d_inode(dentry)))
156 type |= __OVL_PATH_MERGE;
159 if (oe->numlower > 1)
160 type |= __OVL_PATH_MERGE;
165 void ovl_path_upper(struct dentry *dentry, struct path *path)
167 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
169 path->mnt = ovl_upper_mnt(ofs);
170 path->dentry = ovl_dentry_upper(dentry);
173 void ovl_path_lower(struct dentry *dentry, struct path *path)
175 struct ovl_entry *oe = dentry->d_fsdata;
178 path->mnt = oe->lowerstack[0].layer->mnt;
179 path->dentry = oe->lowerstack[0].dentry;
181 *path = (struct path) { };
185 void ovl_path_lowerdata(struct dentry *dentry, struct path *path)
187 struct ovl_entry *oe = dentry->d_fsdata;
190 path->mnt = oe->lowerstack[oe->numlower - 1].layer->mnt;
191 path->dentry = oe->lowerstack[oe->numlower - 1].dentry;
193 *path = (struct path) { };
197 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
199 enum ovl_path_type type = ovl_path_type(dentry);
201 if (!OVL_TYPE_UPPER(type))
202 ovl_path_lower(dentry, path);
204 ovl_path_upper(dentry, path);
209 struct dentry *ovl_dentry_upper(struct dentry *dentry)
211 return ovl_upperdentry_dereference(OVL_I(d_inode(dentry)));
214 struct dentry *ovl_dentry_lower(struct dentry *dentry)
216 struct ovl_entry *oe = dentry->d_fsdata;
218 return oe->numlower ? oe->lowerstack[0].dentry : NULL;
221 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry)
223 struct ovl_entry *oe = dentry->d_fsdata;
225 return oe->numlower ? oe->lowerstack[0].layer : NULL;
229 * ovl_dentry_lower() could return either a data dentry or metacopy dentry
230 * dependig on what is stored in lowerstack[0]. At times we need to find
231 * lower dentry which has data (and not metacopy dentry). This helper
232 * returns the lower data dentry.
234 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry)
236 struct ovl_entry *oe = dentry->d_fsdata;
238 return oe->numlower ? oe->lowerstack[oe->numlower - 1].dentry : NULL;
241 struct dentry *ovl_dentry_real(struct dentry *dentry)
243 return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry);
246 struct dentry *ovl_i_dentry_upper(struct inode *inode)
248 return ovl_upperdentry_dereference(OVL_I(inode));
251 struct inode *ovl_inode_upper(struct inode *inode)
253 struct dentry *upperdentry = ovl_i_dentry_upper(inode);
255 return upperdentry ? d_inode(upperdentry) : NULL;
258 struct inode *ovl_inode_lower(struct inode *inode)
260 return OVL_I(inode)->lower;
263 struct inode *ovl_inode_real(struct inode *inode)
265 return ovl_inode_upper(inode) ?: ovl_inode_lower(inode);
268 /* Return inode which contains lower data. Do not return metacopy */
269 struct inode *ovl_inode_lowerdata(struct inode *inode)
271 if (WARN_ON(!S_ISREG(inode->i_mode)))
274 return OVL_I(inode)->lowerdata ?: ovl_inode_lower(inode);
277 /* Return real inode which contains data. Does not return metacopy inode */
278 struct inode *ovl_inode_realdata(struct inode *inode)
280 struct inode *upperinode;
282 upperinode = ovl_inode_upper(inode);
283 if (upperinode && ovl_has_upperdata(inode))
286 return ovl_inode_lowerdata(inode);
289 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode)
291 return OVL_I(inode)->cache;
294 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache)
296 OVL_I(inode)->cache = cache;
299 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry)
301 set_bit(flag, &OVL_E(dentry)->flags);
304 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry)
306 clear_bit(flag, &OVL_E(dentry)->flags);
309 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry)
311 return test_bit(flag, &OVL_E(dentry)->flags);
314 bool ovl_dentry_is_opaque(struct dentry *dentry)
316 return ovl_dentry_test_flag(OVL_E_OPAQUE, dentry);
319 bool ovl_dentry_is_whiteout(struct dentry *dentry)
321 return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
324 void ovl_dentry_set_opaque(struct dentry *dentry)
326 ovl_dentry_set_flag(OVL_E_OPAQUE, dentry);
330 * For hard links and decoded file handles, it's possible for ovl_dentry_upper()
331 * to return positive, while there's no actual upper alias for the inode.
332 * Copy up code needs to know about the existence of the upper alias, so it
333 * can't use ovl_dentry_upper().
335 bool ovl_dentry_has_upper_alias(struct dentry *dentry)
337 return ovl_dentry_test_flag(OVL_E_UPPER_ALIAS, dentry);
340 void ovl_dentry_set_upper_alias(struct dentry *dentry)
342 ovl_dentry_set_flag(OVL_E_UPPER_ALIAS, dentry);
345 static bool ovl_should_check_upperdata(struct inode *inode)
347 if (!S_ISREG(inode->i_mode))
350 if (!ovl_inode_lower(inode))
356 bool ovl_has_upperdata(struct inode *inode)
358 if (!ovl_should_check_upperdata(inode))
361 if (!ovl_test_flag(OVL_UPPERDATA, inode))
364 * Pairs with smp_wmb() in ovl_set_upperdata(). Main user of
365 * ovl_has_upperdata() is ovl_copy_up_meta_inode_data(). Make sure
366 * if setting of OVL_UPPERDATA is visible, then effects of writes
367 * before that are visible too.
373 void ovl_set_upperdata(struct inode *inode)
376 * Pairs with smp_rmb() in ovl_has_upperdata(). Make sure
377 * if OVL_UPPERDATA flag is visible, then effects of write operations
378 * before it are visible as well.
381 ovl_set_flag(OVL_UPPERDATA, inode);
384 /* Caller should hold ovl_inode->lock */
385 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags)
387 if (!ovl_open_flags_need_copy_up(flags))
390 return !ovl_test_flag(OVL_UPPERDATA, d_inode(dentry));
393 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags)
395 if (!ovl_open_flags_need_copy_up(flags))
398 return !ovl_has_upperdata(d_inode(dentry));
401 bool ovl_redirect_dir(struct super_block *sb)
403 struct ovl_fs *ofs = sb->s_fs_info;
405 return ofs->config.redirect_dir && !ofs->noxattr;
408 const char *ovl_dentry_get_redirect(struct dentry *dentry)
410 return OVL_I(d_inode(dentry))->redirect;
413 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
415 struct ovl_inode *oi = OVL_I(d_inode(dentry));
418 oi->redirect = redirect;
421 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
423 struct inode *upperinode = d_inode(upperdentry);
425 WARN_ON(OVL_I(inode)->__upperdentry);
428 * Make sure upperdentry is consistent before making it visible
431 OVL_I(inode)->__upperdentry = upperdentry;
432 if (inode_unhashed(inode)) {
433 inode->i_private = upperinode;
434 __insert_inode_hash(inode, (unsigned long) upperinode);
438 static void ovl_dir_version_inc(struct dentry *dentry, bool impurity)
440 struct inode *inode = d_inode(dentry);
442 WARN_ON(!inode_is_locked(inode));
443 WARN_ON(!d_is_dir(dentry));
445 * Version is used by readdir code to keep cache consistent.
446 * For merge dirs (or dirs with origin) all changes need to be noted.
447 * For non-merge dirs, cache contains only impure entries (i.e. ones
448 * which have been copied up and have origins), so only need to note
449 * changes to impure entries.
451 if (!ovl_dir_is_real(dentry) || impurity)
452 OVL_I(inode)->version++;
455 void ovl_dir_modified(struct dentry *dentry, bool impurity)
457 /* Copy mtime/ctime */
458 ovl_copyattr(d_inode(ovl_dentry_upper(dentry)), d_inode(dentry));
460 ovl_dir_version_inc(dentry, impurity);
463 u64 ovl_dentry_version_get(struct dentry *dentry)
465 struct inode *inode = d_inode(dentry);
467 WARN_ON(!inode_is_locked(inode));
468 return OVL_I(inode)->version;
471 bool ovl_is_whiteout(struct dentry *dentry)
473 struct inode *inode = dentry->d_inode;
475 return inode && IS_WHITEOUT(inode);
478 struct file *ovl_path_open(struct path *path, int flags)
480 struct inode *inode = d_inode(path->dentry);
483 if (flags & ~(O_ACCMODE | O_LARGEFILE))
486 switch (flags & O_ACCMODE) {
491 acc_mode = MAY_WRITE;
497 err = inode_permission(inode, acc_mode | MAY_OPEN);
501 /* O_NOATIME is an optimization, don't fail if not permitted */
502 if (inode_owner_or_capable(inode))
505 return dentry_open(path, flags, current_cred());
508 /* Caller should hold ovl_inode->lock */
509 static bool ovl_already_copied_up_locked(struct dentry *dentry, int flags)
511 bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED;
513 if (ovl_dentry_upper(dentry) &&
514 (ovl_dentry_has_upper_alias(dentry) || disconnected) &&
515 !ovl_dentry_needs_data_copy_up_locked(dentry, flags))
521 bool ovl_already_copied_up(struct dentry *dentry, int flags)
523 bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED;
526 * Check if copy-up has happened as well as for upper alias (in
527 * case of hard links) is there.
529 * Both checks are lockless:
530 * - false negatives: will recheck under oi->lock
532 * + ovl_dentry_upper() uses memory barriers to ensure the
533 * upper dentry is up-to-date
534 * + ovl_dentry_has_upper_alias() relies on locking of
535 * upper parent i_rwsem to prevent reordering copy-up
538 if (ovl_dentry_upper(dentry) &&
539 (ovl_dentry_has_upper_alias(dentry) || disconnected) &&
540 !ovl_dentry_needs_data_copy_up(dentry, flags))
546 int ovl_copy_up_start(struct dentry *dentry, int flags)
548 struct inode *inode = d_inode(dentry);
551 err = ovl_inode_lock_interruptible(inode);
552 if (!err && ovl_already_copied_up_locked(dentry, flags)) {
553 err = 1; /* Already copied up */
554 ovl_inode_unlock(inode);
560 void ovl_copy_up_end(struct dentry *dentry)
562 ovl_inode_unlock(d_inode(dentry));
565 bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry)
569 res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_ORIGIN, NULL, 0);
571 /* Zero size value means "copied up but origin unknown" */
578 bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
584 if (!d_is_dir(dentry))
587 res = ovl_do_getxattr(OVL_FS(sb), dentry, ox, &val, 1);
588 if (res == 1 && val == 'y')
594 #define OVL_XATTR_OPAQUE_POSTFIX "opaque"
595 #define OVL_XATTR_REDIRECT_POSTFIX "redirect"
596 #define OVL_XATTR_ORIGIN_POSTFIX "origin"
597 #define OVL_XATTR_IMPURE_POSTFIX "impure"
598 #define OVL_XATTR_NLINK_POSTFIX "nlink"
599 #define OVL_XATTR_UPPER_POSTFIX "upper"
600 #define OVL_XATTR_METACOPY_POSTFIX "metacopy"
602 #define OVL_XATTR_TAB_ENTRY(x) \
603 [x] = OVL_XATTR_PREFIX x ## _POSTFIX
605 const char *ovl_xattr_table[] = {
606 OVL_XATTR_TAB_ENTRY(OVL_XATTR_OPAQUE),
607 OVL_XATTR_TAB_ENTRY(OVL_XATTR_REDIRECT),
608 OVL_XATTR_TAB_ENTRY(OVL_XATTR_ORIGIN),
609 OVL_XATTR_TAB_ENTRY(OVL_XATTR_IMPURE),
610 OVL_XATTR_TAB_ENTRY(OVL_XATTR_NLINK),
611 OVL_XATTR_TAB_ENTRY(OVL_XATTR_UPPER),
612 OVL_XATTR_TAB_ENTRY(OVL_XATTR_METACOPY),
615 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
616 enum ovl_xattr ox, const void *value, size_t size,
620 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
625 err = ovl_do_setxattr(ofs, upperdentry, ox, value, size);
627 if (err == -EOPNOTSUPP) {
628 pr_warn("cannot set %s xattr on upper\n", ovl_xattr(ofs, ox));
636 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
640 if (ovl_test_flag(OVL_IMPURE, d_inode(dentry)))
644 * Do not fail when upper doesn't support xattrs.
645 * Upper inodes won't have origin nor redirect xattr anyway.
647 err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE,
650 ovl_set_flag(OVL_IMPURE, d_inode(dentry));
656 * Caller must hold a reference to inode to prevent it from being freed while
657 * it is marked inuse.
659 bool ovl_inuse_trylock(struct dentry *dentry)
661 struct inode *inode = d_inode(dentry);
664 spin_lock(&inode->i_lock);
665 if (!(inode->i_state & I_OVL_INUSE)) {
666 inode->i_state |= I_OVL_INUSE;
669 spin_unlock(&inode->i_lock);
674 void ovl_inuse_unlock(struct dentry *dentry)
677 struct inode *inode = d_inode(dentry);
679 spin_lock(&inode->i_lock);
680 WARN_ON(!(inode->i_state & I_OVL_INUSE));
681 inode->i_state &= ~I_OVL_INUSE;
682 spin_unlock(&inode->i_lock);
686 bool ovl_is_inuse(struct dentry *dentry)
688 struct inode *inode = d_inode(dentry);
691 spin_lock(&inode->i_lock);
692 inuse = (inode->i_state & I_OVL_INUSE);
693 spin_unlock(&inode->i_lock);
699 * Does this overlay dentry need to be indexed on copy up?
701 bool ovl_need_index(struct dentry *dentry)
703 struct dentry *lower = ovl_dentry_lower(dentry);
705 if (!lower || !ovl_indexdir(dentry->d_sb))
708 /* Index all files for NFS export and consistency verification */
709 if (ovl_index_all(dentry->d_sb))
712 /* Index only lower hardlinks on copy up */
713 if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1)
719 /* Caller must hold OVL_I(inode)->lock */
720 static void ovl_cleanup_index(struct dentry *dentry)
722 struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
723 struct inode *dir = indexdir->d_inode;
724 struct dentry *lowerdentry = ovl_dentry_lower(dentry);
725 struct dentry *upperdentry = ovl_dentry_upper(dentry);
726 struct dentry *index = NULL;
728 struct qstr name = { };
731 err = ovl_get_index_name(lowerdentry, &name);
735 inode = d_inode(upperdentry);
736 if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) {
737 pr_warn_ratelimited("cleanup linked index (%pd2, ino=%lu, nlink=%u)\n",
738 upperdentry, inode->i_ino, inode->i_nlink);
740 * We either have a bug with persistent union nlink or a lower
741 * hardlink was added while overlay is mounted. Adding a lower
742 * hardlink and then unlinking all overlay hardlinks would drop
743 * overlay nlink to zero before all upper inodes are unlinked.
744 * As a safety measure, when that situation is detected, set
745 * the overlay nlink to the index inode nlink minus one for the
746 * index entry itself.
748 set_nlink(d_inode(dentry), inode->i_nlink - 1);
749 ovl_set_nlink_upper(dentry);
753 inode_lock_nested(dir, I_MUTEX_PARENT);
754 index = lookup_one_len(name.name, indexdir, name.len);
755 err = PTR_ERR(index);
758 } else if (ovl_index_all(dentry->d_sb)) {
759 /* Whiteout orphan index to block future open by handle */
760 err = ovl_cleanup_and_whiteout(OVL_FS(dentry->d_sb),
763 /* Cleanup orphan index entries */
764 err = ovl_cleanup(dir, index);
777 pr_err("cleanup index of '%pd2' failed (%i)\n", dentry, err);
782 * Operations that change overlay inode and upper inode nlink need to be
783 * synchronized with copy up for persistent nlink accounting.
785 int ovl_nlink_start(struct dentry *dentry)
787 struct inode *inode = d_inode(dentry);
788 const struct cred *old_cred;
795 * With inodes index is enabled, we store the union overlay nlink
796 * in an xattr on the index inode. When whiting out an indexed lower,
797 * we need to decrement the overlay persistent nlink, but before the
798 * first copy up, we have no upper index inode to store the xattr.
800 * As a workaround, before whiteout/rename over an indexed lower,
801 * copy up to create the upper index. Creating the upper index will
802 * initialize the overlay nlink, so it could be dropped if unlink
803 * or rename succeeds.
805 * TODO: implement metadata only index copy up when called with
806 * ovl_copy_up_flags(dentry, O_PATH).
808 if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) {
809 err = ovl_copy_up(dentry);
814 err = ovl_inode_lock_interruptible(inode);
818 if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, inode))
821 old_cred = ovl_override_creds(dentry->d_sb);
823 * The overlay inode nlink should be incremented/decremented IFF the
824 * upper operation succeeds, along with nlink change of upper inode.
825 * Therefore, before link/unlink/rename, we store the union nlink
826 * value relative to the upper inode nlink in an upper inode xattr.
828 err = ovl_set_nlink_upper(dentry);
829 revert_creds(old_cred);
833 ovl_inode_unlock(inode);
838 void ovl_nlink_end(struct dentry *dentry)
840 struct inode *inode = d_inode(dentry);
842 if (ovl_test_flag(OVL_INDEX, inode) && inode->i_nlink == 0) {
843 const struct cred *old_cred;
845 old_cred = ovl_override_creds(dentry->d_sb);
846 ovl_cleanup_index(dentry);
847 revert_creds(old_cred);
850 ovl_inode_unlock(inode);
853 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir)
855 /* Workdir should not be the same as upperdir */
856 if (workdir == upperdir)
859 /* Workdir should not be subdir of upperdir and vice versa */
860 if (lock_rename(workdir, upperdir) != NULL)
866 unlock_rename(workdir, upperdir);
868 pr_err("failed to lock workdir+upperdir\n");
872 /* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */
873 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry)
877 /* Only regular files can have metacopy xattr */
878 if (!S_ISREG(d_inode(dentry)->i_mode))
881 res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_METACOPY, NULL, 0);
883 if (res == -ENODATA || res == -EOPNOTSUPP)
890 pr_warn_ratelimited("failed to get metacopy (%i)\n", res);
894 bool ovl_is_metacopy_dentry(struct dentry *dentry)
896 struct ovl_entry *oe = dentry->d_fsdata;
898 if (!d_is_reg(dentry))
901 if (ovl_dentry_upper(dentry)) {
902 if (!ovl_has_upperdata(d_inode(dentry)))
907 return (oe->numlower > 1);
910 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
914 char *s, *next, *buf = NULL;
916 res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, NULL, 0);
917 if (res == -ENODATA || res == -EOPNOTSUPP)
924 buf = kzalloc(res + padding + 1, GFP_KERNEL);
926 return ERR_PTR(-ENOMEM);
928 res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, buf, res);
935 for (s = buf; *s++ == '/'; s = next) {
936 next = strchrnul(s, '/');
941 if (strchr(buf, '/') != NULL)
947 pr_warn_ratelimited("invalid redirect (%s)\n", buf);
951 pr_warn_ratelimited("failed to get redirect (%i)\n", res);
958 * ovl_sync_status() - Check fs sync status for volatile mounts
960 * Returns 1 if this is not a volatile mount and a real sync is required.
962 * Returns 0 if syncing can be skipped because mount is volatile, and no errors
963 * have occurred on the upperdir since the mount.
965 * Returns -errno if it is a volatile mount, and the error that occurred since
966 * the last mount. If the error code changes, it'll return the latest error
970 int ovl_sync_status(struct ovl_fs *ofs)
972 struct vfsmount *mnt;
974 if (ovl_should_sync(ofs))
977 mnt = ovl_upper_mnt(ofs);
981 return errseq_check(&mnt->mnt_sb->s_wb_err, ofs->errseq);