2 * Copyright (C) 2011 Novell Inc.
3 * Copyright (C) 2016 Red Hat, Inc.
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
11 #include <linux/mount.h>
12 #include <linux/slab.h>
13 #include <linux/cred.h>
14 #include <linux/xattr.h>
15 #include <linux/exportfs.h>
16 #include <linux/uuid.h>
17 #include <linux/namei.h>
18 #include <linux/ratelimit.h>
19 #include "overlayfs.h"
21 int ovl_want_write(struct dentry *dentry)
23 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
24 return mnt_want_write(ofs->upper_mnt);
27 void ovl_drop_write(struct dentry *dentry)
29 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
30 mnt_drop_write(ofs->upper_mnt);
33 struct dentry *ovl_workdir(struct dentry *dentry)
35 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
39 const struct cred *ovl_override_creds(struct super_block *sb)
41 struct ovl_fs *ofs = sb->s_fs_info;
43 return override_creds(ofs->creator_cred);
46 struct super_block *ovl_same_sb(struct super_block *sb)
48 struct ovl_fs *ofs = sb->s_fs_info;
51 return ofs->upper_mnt->mnt_sb;
52 else if (ofs->numlowerfs == 1 && !ofs->upper_mnt)
53 return ofs->lower_fs[0].sb;
59 * Check if underlying fs supports file handles and try to determine encoding
60 * type, in order to deduce maximum inode number used by fs.
62 * Return 0 if file handles are not supported.
63 * Return 1 (FILEID_INO32_GEN) if fs uses the default 32bit inode encoding.
64 * Return -1 if fs uses a non default encoding with unknown inode size.
66 int ovl_can_decode_fh(struct super_block *sb)
68 if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry ||
69 uuid_is_null(&sb->s_uuid))
72 return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN;
75 struct dentry *ovl_indexdir(struct super_block *sb)
77 struct ovl_fs *ofs = sb->s_fs_info;
82 /* Index all files on copy up. For now only enabled for NFS export */
83 bool ovl_index_all(struct super_block *sb)
85 struct ovl_fs *ofs = sb->s_fs_info;
87 return ofs->config.nfs_export && ofs->config.index;
90 /* Verify lower origin on lookup. For now only enabled for NFS export */
91 bool ovl_verify_lower(struct super_block *sb)
93 struct ovl_fs *ofs = sb->s_fs_info;
95 return ofs->config.nfs_export && ofs->config.index;
98 struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
100 size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
101 struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
104 oe->numlower = numlower;
109 bool ovl_dentry_remote(struct dentry *dentry)
111 return dentry->d_flags &
112 (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
116 bool ovl_dentry_weird(struct dentry *dentry)
118 return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
119 DCACHE_MANAGE_TRANSIT |
124 enum ovl_path_type ovl_path_type(struct dentry *dentry)
126 struct ovl_entry *oe = dentry->d_fsdata;
127 enum ovl_path_type type = 0;
129 if (ovl_dentry_upper(dentry)) {
130 type = __OVL_PATH_UPPER;
133 * Non-dir dentry can hold lower dentry of its copy up origin.
136 if (ovl_test_flag(OVL_CONST_INO, d_inode(dentry)))
137 type |= __OVL_PATH_ORIGIN;
138 if (d_is_dir(dentry) ||
139 !ovl_has_upperdata(d_inode(dentry)))
140 type |= __OVL_PATH_MERGE;
143 if (oe->numlower > 1)
144 type |= __OVL_PATH_MERGE;
149 void ovl_path_upper(struct dentry *dentry, struct path *path)
151 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
153 path->mnt = ofs->upper_mnt;
154 path->dentry = ovl_dentry_upper(dentry);
157 void ovl_path_lower(struct dentry *dentry, struct path *path)
159 struct ovl_entry *oe = dentry->d_fsdata;
162 path->mnt = oe->lowerstack[0].layer->mnt;
163 path->dentry = oe->lowerstack[0].dentry;
165 *path = (struct path) { };
169 void ovl_path_lowerdata(struct dentry *dentry, struct path *path)
171 struct ovl_entry *oe = dentry->d_fsdata;
174 path->mnt = oe->lowerstack[oe->numlower - 1].layer->mnt;
175 path->dentry = oe->lowerstack[oe->numlower - 1].dentry;
177 *path = (struct path) { };
181 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
183 enum ovl_path_type type = ovl_path_type(dentry);
185 if (!OVL_TYPE_UPPER(type))
186 ovl_path_lower(dentry, path);
188 ovl_path_upper(dentry, path);
193 struct dentry *ovl_dentry_upper(struct dentry *dentry)
195 return ovl_upperdentry_dereference(OVL_I(d_inode(dentry)));
198 struct dentry *ovl_dentry_lower(struct dentry *dentry)
200 struct ovl_entry *oe = dentry->d_fsdata;
202 return oe->numlower ? oe->lowerstack[0].dentry : NULL;
205 struct ovl_layer *ovl_layer_lower(struct dentry *dentry)
207 struct ovl_entry *oe = dentry->d_fsdata;
209 return oe->numlower ? oe->lowerstack[0].layer : NULL;
213 * ovl_dentry_lower() could return either a data dentry or metacopy dentry
214 * dependig on what is stored in lowerstack[0]. At times we need to find
215 * lower dentry which has data (and not metacopy dentry). This helper
216 * returns the lower data dentry.
218 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry)
220 struct ovl_entry *oe = dentry->d_fsdata;
222 return oe->numlower ? oe->lowerstack[oe->numlower - 1].dentry : NULL;
225 struct dentry *ovl_dentry_real(struct dentry *dentry)
227 return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry);
230 struct dentry *ovl_i_dentry_upper(struct inode *inode)
232 return ovl_upperdentry_dereference(OVL_I(inode));
235 struct inode *ovl_inode_upper(struct inode *inode)
237 struct dentry *upperdentry = ovl_i_dentry_upper(inode);
239 return upperdentry ? d_inode(upperdentry) : NULL;
242 struct inode *ovl_inode_lower(struct inode *inode)
244 return OVL_I(inode)->lower;
247 struct inode *ovl_inode_real(struct inode *inode)
249 return ovl_inode_upper(inode) ?: ovl_inode_lower(inode);
252 /* Return inode which contains lower data. Do not return metacopy */
253 struct inode *ovl_inode_lowerdata(struct inode *inode)
255 if (WARN_ON(!S_ISREG(inode->i_mode)))
258 return OVL_I(inode)->lowerdata ?: ovl_inode_lower(inode);
261 /* Return real inode which contains data. Does not return metacopy inode */
262 struct inode *ovl_inode_realdata(struct inode *inode)
264 struct inode *upperinode;
266 upperinode = ovl_inode_upper(inode);
267 if (upperinode && ovl_has_upperdata(inode))
270 return ovl_inode_lowerdata(inode);
273 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode)
275 return OVL_I(inode)->cache;
278 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache)
280 OVL_I(inode)->cache = cache;
283 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry)
285 set_bit(flag, &OVL_E(dentry)->flags);
288 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry)
290 clear_bit(flag, &OVL_E(dentry)->flags);
293 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry)
295 return test_bit(flag, &OVL_E(dentry)->flags);
298 bool ovl_dentry_is_opaque(struct dentry *dentry)
300 return ovl_dentry_test_flag(OVL_E_OPAQUE, dentry);
303 bool ovl_dentry_is_whiteout(struct dentry *dentry)
305 return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
308 void ovl_dentry_set_opaque(struct dentry *dentry)
310 ovl_dentry_set_flag(OVL_E_OPAQUE, dentry);
314 * For hard links and decoded file handles, it's possible for ovl_dentry_upper()
315 * to return positive, while there's no actual upper alias for the inode.
316 * Copy up code needs to know about the existence of the upper alias, so it
317 * can't use ovl_dentry_upper().
319 bool ovl_dentry_has_upper_alias(struct dentry *dentry)
321 return ovl_dentry_test_flag(OVL_E_UPPER_ALIAS, dentry);
324 void ovl_dentry_set_upper_alias(struct dentry *dentry)
326 ovl_dentry_set_flag(OVL_E_UPPER_ALIAS, dentry);
329 static bool ovl_should_check_upperdata(struct inode *inode)
331 if (!S_ISREG(inode->i_mode))
334 if (!ovl_inode_lower(inode))
340 bool ovl_has_upperdata(struct inode *inode)
342 if (!ovl_should_check_upperdata(inode))
345 if (!ovl_test_flag(OVL_UPPERDATA, inode))
348 * Pairs with smp_wmb() in ovl_set_upperdata(). Main user of
349 * ovl_has_upperdata() is ovl_copy_up_meta_inode_data(). Make sure
350 * if setting of OVL_UPPERDATA is visible, then effects of writes
351 * before that are visible too.
357 void ovl_set_upperdata(struct inode *inode)
360 * Pairs with smp_rmb() in ovl_has_upperdata(). Make sure
361 * if OVL_UPPERDATA flag is visible, then effects of write operations
362 * before it are visible as well.
365 ovl_set_flag(OVL_UPPERDATA, inode);
368 /* Caller should hold ovl_inode->lock */
369 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags)
371 if (!ovl_open_flags_need_copy_up(flags))
374 return !ovl_test_flag(OVL_UPPERDATA, d_inode(dentry));
377 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags)
379 if (!ovl_open_flags_need_copy_up(flags))
382 return !ovl_has_upperdata(d_inode(dentry));
385 bool ovl_redirect_dir(struct super_block *sb)
387 struct ovl_fs *ofs = sb->s_fs_info;
389 return ofs->config.redirect_dir && !ofs->noxattr;
392 const char *ovl_dentry_get_redirect(struct dentry *dentry)
394 return OVL_I(d_inode(dentry))->redirect;
397 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
399 struct ovl_inode *oi = OVL_I(d_inode(dentry));
402 oi->redirect = redirect;
405 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
406 struct dentry *lowerdentry, struct dentry *lowerdata)
408 struct inode *realinode = d_inode(upperdentry ?: lowerdentry);
411 OVL_I(inode)->__upperdentry = upperdentry;
413 OVL_I(inode)->lower = igrab(d_inode(lowerdentry));
415 OVL_I(inode)->lowerdata = igrab(d_inode(lowerdata));
417 ovl_copyattr(realinode, inode);
418 ovl_copyflags(realinode, inode);
420 inode->i_ino = realinode->i_ino;
423 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
425 struct inode *upperinode = d_inode(upperdentry);
427 WARN_ON(OVL_I(inode)->__upperdentry);
430 * Make sure upperdentry is consistent before making it visible
433 OVL_I(inode)->__upperdentry = upperdentry;
434 if (inode_unhashed(inode)) {
436 inode->i_ino = upperinode->i_ino;
437 inode->i_private = upperinode;
438 __insert_inode_hash(inode, (unsigned long) upperinode);
442 static void ovl_dentry_version_inc(struct dentry *dentry, bool impurity)
444 struct inode *inode = d_inode(dentry);
446 WARN_ON(!inode_is_locked(inode));
448 * Version is used by readdir code to keep cache consistent. For merge
449 * dirs all changes need to be noted. For non-merge dirs, cache only
450 * contains impure (ones which have been copied up and have origins)
451 * entries, so only need to note changes to impure entries.
453 if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity)
454 OVL_I(inode)->version++;
457 void ovl_dir_modified(struct dentry *dentry, bool impurity)
459 /* Copy mtime/ctime */
460 ovl_copyattr(d_inode(ovl_dentry_upper(dentry)), d_inode(dentry));
462 ovl_dentry_version_inc(dentry, impurity);
465 u64 ovl_dentry_version_get(struct dentry *dentry)
467 struct inode *inode = d_inode(dentry);
469 WARN_ON(!inode_is_locked(inode));
470 return OVL_I(inode)->version;
473 bool ovl_is_whiteout(struct dentry *dentry)
475 struct inode *inode = dentry->d_inode;
477 return inode && IS_WHITEOUT(inode);
480 struct file *ovl_path_open(struct path *path, int flags)
482 return dentry_open(path, flags | O_NOATIME, current_cred());
485 /* Caller should hold ovl_inode->lock */
486 static bool ovl_already_copied_up_locked(struct dentry *dentry, int flags)
488 bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED;
490 if (ovl_dentry_upper(dentry) &&
491 (ovl_dentry_has_upper_alias(dentry) || disconnected) &&
492 !ovl_dentry_needs_data_copy_up_locked(dentry, flags))
498 bool ovl_already_copied_up(struct dentry *dentry, int flags)
500 bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED;
503 * Check if copy-up has happened as well as for upper alias (in
504 * case of hard links) is there.
506 * Both checks are lockless:
507 * - false negatives: will recheck under oi->lock
509 * + ovl_dentry_upper() uses memory barriers to ensure the
510 * upper dentry is up-to-date
511 * + ovl_dentry_has_upper_alias() relies on locking of
512 * upper parent i_rwsem to prevent reordering copy-up
515 if (ovl_dentry_upper(dentry) &&
516 (ovl_dentry_has_upper_alias(dentry) || disconnected) &&
517 !ovl_dentry_needs_data_copy_up(dentry, flags))
523 int ovl_copy_up_start(struct dentry *dentry, int flags)
525 struct ovl_inode *oi = OVL_I(d_inode(dentry));
528 err = mutex_lock_interruptible(&oi->lock);
529 if (!err && ovl_already_copied_up_locked(dentry, flags)) {
530 err = 1; /* Already copied up */
531 mutex_unlock(&oi->lock);
537 void ovl_copy_up_end(struct dentry *dentry)
539 mutex_unlock(&OVL_I(d_inode(dentry))->lock);
542 bool ovl_check_origin_xattr(struct dentry *dentry)
546 res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0);
548 /* Zero size value means "copied up but origin unknown" */
555 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name)
560 if (!d_is_dir(dentry))
563 res = vfs_getxattr(dentry, name, &val, 1);
564 if (res == 1 && val == 'y')
570 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
571 const char *name, const void *value, size_t size,
575 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
580 err = ovl_do_setxattr(upperdentry, name, value, size, 0);
582 if (err == -EOPNOTSUPP) {
583 pr_warn("overlayfs: cannot set %s xattr on upper\n", name);
591 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
595 if (ovl_test_flag(OVL_IMPURE, d_inode(dentry)))
599 * Do not fail when upper doesn't support xattrs.
600 * Upper inodes won't have origin nor redirect xattr anyway.
602 err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE,
605 ovl_set_flag(OVL_IMPURE, d_inode(dentry));
610 void ovl_set_flag(unsigned long flag, struct inode *inode)
612 set_bit(flag, &OVL_I(inode)->flags);
615 void ovl_clear_flag(unsigned long flag, struct inode *inode)
617 clear_bit(flag, &OVL_I(inode)->flags);
620 bool ovl_test_flag(unsigned long flag, struct inode *inode)
622 return test_bit(flag, &OVL_I(inode)->flags);
626 * Caller must hold a reference to inode to prevent it from being freed while
627 * it is marked inuse.
629 bool ovl_inuse_trylock(struct dentry *dentry)
631 struct inode *inode = d_inode(dentry);
634 spin_lock(&inode->i_lock);
635 if (!(inode->i_state & I_OVL_INUSE)) {
636 inode->i_state |= I_OVL_INUSE;
639 spin_unlock(&inode->i_lock);
644 void ovl_inuse_unlock(struct dentry *dentry)
647 struct inode *inode = d_inode(dentry);
649 spin_lock(&inode->i_lock);
650 WARN_ON(!(inode->i_state & I_OVL_INUSE));
651 inode->i_state &= ~I_OVL_INUSE;
652 spin_unlock(&inode->i_lock);
656 bool ovl_is_inuse(struct dentry *dentry)
658 struct inode *inode = d_inode(dentry);
661 spin_lock(&inode->i_lock);
662 inuse = (inode->i_state & I_OVL_INUSE);
663 spin_unlock(&inode->i_lock);
669 * Does this overlay dentry need to be indexed on copy up?
671 bool ovl_need_index(struct dentry *dentry)
673 struct dentry *lower = ovl_dentry_lower(dentry);
675 if (!lower || !ovl_indexdir(dentry->d_sb))
678 /* Index all files for NFS export and consistency verification */
679 if (ovl_index_all(dentry->d_sb))
682 /* Index only lower hardlinks on copy up */
683 if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1)
689 /* Caller must hold OVL_I(inode)->lock */
690 static void ovl_cleanup_index(struct dentry *dentry)
692 struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
693 struct inode *dir = indexdir->d_inode;
694 struct dentry *lowerdentry = ovl_dentry_lower(dentry);
695 struct dentry *upperdentry = ovl_dentry_upper(dentry);
696 struct dentry *index = NULL;
698 struct qstr name = { };
701 err = ovl_get_index_name(lowerdentry, &name);
705 inode = d_inode(upperdentry);
706 if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) {
707 pr_warn_ratelimited("overlayfs: cleanup linked index (%pd2, ino=%lu, nlink=%u)\n",
708 upperdentry, inode->i_ino, inode->i_nlink);
710 * We either have a bug with persistent union nlink or a lower
711 * hardlink was added while overlay is mounted. Adding a lower
712 * hardlink and then unlinking all overlay hardlinks would drop
713 * overlay nlink to zero before all upper inodes are unlinked.
714 * As a safety measure, when that situation is detected, set
715 * the overlay nlink to the index inode nlink minus one for the
716 * index entry itself.
718 set_nlink(d_inode(dentry), inode->i_nlink - 1);
719 ovl_set_nlink_upper(dentry);
723 inode_lock_nested(dir, I_MUTEX_PARENT);
724 index = lookup_one_len(name.name, indexdir, name.len);
725 err = PTR_ERR(index);
728 } else if (ovl_index_all(dentry->d_sb)) {
729 /* Whiteout orphan index to block future open by handle */
730 err = ovl_cleanup_and_whiteout(indexdir, dir, index);
732 /* Cleanup orphan index entries */
733 err = ovl_cleanup(dir, index);
746 pr_err("overlayfs: cleanup index of '%pd2' failed (%i)\n", dentry, err);
751 * Operations that change overlay inode and upper inode nlink need to be
752 * synchronized with copy up for persistent nlink accounting.
754 int ovl_nlink_start(struct dentry *dentry, bool *locked)
756 struct ovl_inode *oi = OVL_I(d_inode(dentry));
757 const struct cred *old_cred;
760 if (!d_inode(dentry))
764 * With inodes index is enabled, we store the union overlay nlink
765 * in an xattr on the index inode. When whiting out an indexed lower,
766 * we need to decrement the overlay persistent nlink, but before the
767 * first copy up, we have no upper index inode to store the xattr.
769 * As a workaround, before whiteout/rename over an indexed lower,
770 * copy up to create the upper index. Creating the upper index will
771 * initialize the overlay nlink, so it could be dropped if unlink
772 * or rename succeeds.
774 * TODO: implement metadata only index copy up when called with
775 * ovl_copy_up_flags(dentry, O_PATH).
777 if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) {
778 err = ovl_copy_up(dentry);
783 err = mutex_lock_interruptible(&oi->lock);
787 if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, d_inode(dentry)))
790 old_cred = ovl_override_creds(dentry->d_sb);
792 * The overlay inode nlink should be incremented/decremented IFF the
793 * upper operation succeeds, along with nlink change of upper inode.
794 * Therefore, before link/unlink/rename, we store the union nlink
795 * value relative to the upper inode nlink in an upper inode xattr.
797 err = ovl_set_nlink_upper(dentry);
798 revert_creds(old_cred);
802 mutex_unlock(&oi->lock);
809 void ovl_nlink_end(struct dentry *dentry, bool locked)
812 if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) &&
813 d_inode(dentry)->i_nlink == 0) {
814 const struct cred *old_cred;
816 old_cred = ovl_override_creds(dentry->d_sb);
817 ovl_cleanup_index(dentry);
818 revert_creds(old_cred);
821 mutex_unlock(&OVL_I(d_inode(dentry))->lock);
825 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir)
827 /* Workdir should not be the same as upperdir */
828 if (workdir == upperdir)
831 /* Workdir should not be subdir of upperdir and vice versa */
832 if (lock_rename(workdir, upperdir) != NULL)
838 unlock_rename(workdir, upperdir);
840 pr_err("overlayfs: failed to lock workdir+upperdir\n");
844 /* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */
845 int ovl_check_metacopy_xattr(struct dentry *dentry)
849 /* Only regular files can have metacopy xattr */
850 if (!S_ISREG(d_inode(dentry)->i_mode))
853 res = vfs_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0);
855 if (res == -ENODATA || res == -EOPNOTSUPP)
862 pr_warn_ratelimited("overlayfs: failed to get metacopy (%i)\n", res);
866 bool ovl_is_metacopy_dentry(struct dentry *dentry)
868 struct ovl_entry *oe = dentry->d_fsdata;
870 if (!d_is_reg(dentry))
873 if (ovl_dentry_upper(dentry)) {
874 if (!ovl_has_upperdata(d_inode(dentry)))
879 return (oe->numlower > 1);
882 ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
888 res = vfs_getxattr(dentry, name, NULL, 0);
890 if (res == -ENODATA || res == -EOPNOTSUPP)
896 buf = kzalloc(res + padding, GFP_KERNEL);
900 res = vfs_getxattr(dentry, name, buf, res);
909 pr_warn_ratelimited("overlayfs: failed to get xattr %s: err=%zi)\n",
915 char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
918 char *s, *next, *buf = NULL;
920 res = ovl_getxattr(dentry, OVL_XATTR_REDIRECT, &buf, padding + 1);
929 for (s = buf; *s++ == '/'; s = next) {
930 next = strchrnul(s, '/');
935 if (strchr(buf, '/') != NULL)
941 pr_warn_ratelimited("overlayfs: invalid redirect (%s)\n", buf);