3 * Copyright (C) 2011 Novell 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.
10 #include <uapi/linux/magic.h>
12 #include <linux/namei.h>
13 #include <linux/xattr.h>
14 #include <linux/mount.h>
15 #include <linux/parser.h>
16 #include <linux/module.h>
17 #include <linux/statfs.h>
18 #include <linux/seq_file.h>
19 #include <linux/posix_acl_xattr.h>
20 #include "overlayfs.h"
21 #include "ovl_entry.h"
23 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
24 MODULE_DESCRIPTION("Overlay filesystem");
25 MODULE_LICENSE("GPL");
30 #define OVL_MAX_STACK 500
32 static bool ovl_redirect_dir_def
= IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR
);
33 module_param_named(redirect_dir
, ovl_redirect_dir_def
, bool, 0644);
34 MODULE_PARM_DESC(ovl_redirect_dir_def
,
35 "Default to on or off for the redirect_dir feature");
37 static void ovl_dentry_release(struct dentry
*dentry
)
39 struct ovl_entry
*oe
= dentry
->d_fsdata
;
44 dput(oe
->__upperdentry
);
46 for (i
= 0; i
< oe
->numlower
; i
++)
47 dput(oe
->lowerstack
[i
].dentry
);
52 static struct dentry
*ovl_d_real(struct dentry
*dentry
,
53 const struct inode
*inode
,
54 unsigned int open_flags
)
58 if (!d_is_reg(dentry
)) {
59 if (!inode
|| inode
== d_inode(dentry
))
64 if (d_is_negative(dentry
))
68 int err
= ovl_open_maybe_copy_up(dentry
, open_flags
);
74 real
= ovl_dentry_upper(dentry
);
75 if (real
&& (!inode
|| inode
== d_inode(real
)))
78 real
= ovl_dentry_lower(dentry
);
82 /* Handle recursion */
83 real
= d_real(real
, inode
, open_flags
);
85 if (!inode
|| inode
== d_inode(real
))
88 WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry
,
89 inode
? inode
->i_sb
->s_id
: "NULL", inode
? inode
->i_ino
: 0);
93 static int ovl_dentry_revalidate(struct dentry
*dentry
, unsigned int flags
)
95 struct ovl_entry
*oe
= dentry
->d_fsdata
;
99 for (i
= 0; i
< oe
->numlower
; i
++) {
100 struct dentry
*d
= oe
->lowerstack
[i
].dentry
;
102 if (d
->d_flags
& DCACHE_OP_REVALIDATE
) {
103 ret
= d
->d_op
->d_revalidate(d
, flags
);
107 if (!(flags
& LOOKUP_RCU
))
116 static int ovl_dentry_weak_revalidate(struct dentry
*dentry
, unsigned int flags
)
118 struct ovl_entry
*oe
= dentry
->d_fsdata
;
122 for (i
= 0; i
< oe
->numlower
; i
++) {
123 struct dentry
*d
= oe
->lowerstack
[i
].dentry
;
125 if (d
->d_flags
& DCACHE_OP_WEAK_REVALIDATE
) {
126 ret
= d
->d_op
->d_weak_revalidate(d
, flags
);
134 static const struct dentry_operations ovl_dentry_operations
= {
135 .d_release
= ovl_dentry_release
,
136 .d_real
= ovl_d_real
,
139 static const struct dentry_operations ovl_reval_dentry_operations
= {
140 .d_release
= ovl_dentry_release
,
141 .d_real
= ovl_d_real
,
142 .d_revalidate
= ovl_dentry_revalidate
,
143 .d_weak_revalidate
= ovl_dentry_weak_revalidate
,
146 static void ovl_put_super(struct super_block
*sb
)
148 struct ovl_fs
*ufs
= sb
->s_fs_info
;
152 mntput(ufs
->upper_mnt
);
153 for (i
= 0; i
< ufs
->numlower
; i
++)
154 mntput(ufs
->lower_mnt
[i
]);
155 kfree(ufs
->lower_mnt
);
157 kfree(ufs
->config
.lowerdir
);
158 kfree(ufs
->config
.upperdir
);
159 kfree(ufs
->config
.workdir
);
160 put_cred(ufs
->creator_cred
);
164 static int ovl_sync_fs(struct super_block
*sb
, int wait
)
166 struct ovl_fs
*ufs
= sb
->s_fs_info
;
167 struct super_block
*upper_sb
;
172 upper_sb
= ufs
->upper_mnt
->mnt_sb
;
173 if (!upper_sb
->s_op
->sync_fs
)
176 /* real inodes have already been synced by sync_filesystem(ovl_sb) */
177 down_read(&upper_sb
->s_umount
);
178 ret
= upper_sb
->s_op
->sync_fs(upper_sb
, wait
);
179 up_read(&upper_sb
->s_umount
);
185 * @sb: The overlayfs super block
186 * @buf: The struct kstatfs to fill in with stats
188 * Get the filesystem statistics. As writes always target the upper layer
189 * filesystem pass the statfs to the upper filesystem (if it exists)
191 static int ovl_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
193 struct ovl_fs
*ofs
= dentry
->d_sb
->s_fs_info
;
194 struct dentry
*root_dentry
= dentry
->d_sb
->s_root
;
198 ovl_path_real(root_dentry
, &path
);
200 err
= vfs_statfs(&path
, buf
);
202 buf
->f_namelen
= ofs
->namelen
;
203 buf
->f_type
= OVERLAYFS_SUPER_MAGIC
;
212 * Prints the mount options for a given superblock.
213 * Returns zero; does not fail.
215 static int ovl_show_options(struct seq_file
*m
, struct dentry
*dentry
)
217 struct super_block
*sb
= dentry
->d_sb
;
218 struct ovl_fs
*ufs
= sb
->s_fs_info
;
220 seq_show_option(m
, "lowerdir", ufs
->config
.lowerdir
);
221 if (ufs
->config
.upperdir
) {
222 seq_show_option(m
, "upperdir", ufs
->config
.upperdir
);
223 seq_show_option(m
, "workdir", ufs
->config
.workdir
);
225 if (ufs
->config
.default_permissions
)
226 seq_puts(m
, ",default_permissions");
227 if (ufs
->config
.redirect_dir
!= ovl_redirect_dir_def
)
228 seq_printf(m
, ",redirect_dir=%s",
229 ufs
->config
.redirect_dir
? "on" : "off");
233 static int ovl_remount(struct super_block
*sb
, int *flags
, char *data
)
235 struct ovl_fs
*ufs
= sb
->s_fs_info
;
237 if (!(*flags
& MS_RDONLY
) && (!ufs
->upper_mnt
|| !ufs
->workdir
))
243 static const struct super_operations ovl_super_operations
= {
244 .put_super
= ovl_put_super
,
245 .sync_fs
= ovl_sync_fs
,
246 .statfs
= ovl_statfs
,
247 .show_options
= ovl_show_options
,
248 .remount_fs
= ovl_remount
,
249 .drop_inode
= generic_delete_inode
,
256 OPT_DEFAULT_PERMISSIONS
,
258 OPT_REDIRECT_DIR_OFF
,
262 static const match_table_t ovl_tokens
= {
263 {OPT_LOWERDIR
, "lowerdir=%s"},
264 {OPT_UPPERDIR
, "upperdir=%s"},
265 {OPT_WORKDIR
, "workdir=%s"},
266 {OPT_DEFAULT_PERMISSIONS
, "default_permissions"},
267 {OPT_REDIRECT_DIR_ON
, "redirect_dir=on"},
268 {OPT_REDIRECT_DIR_OFF
, "redirect_dir=off"},
272 static char *ovl_next_opt(char **s
)
280 for (p
= sbegin
; *p
; p
++) {
285 } else if (*p
== ',') {
295 static int ovl_parse_opt(char *opt
, struct ovl_config
*config
)
299 while ((p
= ovl_next_opt(&opt
)) != NULL
) {
301 substring_t args
[MAX_OPT_ARGS
];
306 token
= match_token(p
, ovl_tokens
, args
);
309 kfree(config
->upperdir
);
310 config
->upperdir
= match_strdup(&args
[0]);
311 if (!config
->upperdir
)
316 kfree(config
->lowerdir
);
317 config
->lowerdir
= match_strdup(&args
[0]);
318 if (!config
->lowerdir
)
323 kfree(config
->workdir
);
324 config
->workdir
= match_strdup(&args
[0]);
325 if (!config
->workdir
)
329 case OPT_DEFAULT_PERMISSIONS
:
330 config
->default_permissions
= true;
333 case OPT_REDIRECT_DIR_ON
:
334 config
->redirect_dir
= true;
337 case OPT_REDIRECT_DIR_OFF
:
338 config
->redirect_dir
= false;
342 pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p
);
347 /* Workdir is useless in non-upper mount */
348 if (!config
->upperdir
&& config
->workdir
) {
349 pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
351 kfree(config
->workdir
);
352 config
->workdir
= NULL
;
358 #define OVL_WORKDIR_NAME "work"
360 static struct dentry
*ovl_workdir_create(struct vfsmount
*mnt
,
361 struct dentry
*dentry
)
363 struct inode
*dir
= dentry
->d_inode
;
366 bool retried
= false;
368 err
= mnt_want_write(mnt
);
372 inode_lock_nested(dir
, I_MUTEX_PARENT
);
374 work
= lookup_one_len(OVL_WORKDIR_NAME
, dentry
,
375 strlen(OVL_WORKDIR_NAME
));
378 struct iattr attr
= {
379 .ia_valid
= ATTR_MODE
,
380 .ia_mode
= S_IFDIR
| 0,
389 ovl_workdir_cleanup(dir
, mnt
, work
, 0);
394 err
= ovl_create_real(dir
, work
,
395 &(struct cattr
){.mode
= S_IFDIR
| 0},
401 * Try to remove POSIX ACL xattrs from workdir. We are good if:
403 * a) success (there was a POSIX ACL xattr and was removed)
404 * b) -ENODATA (there was no POSIX ACL xattr)
405 * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported)
407 * There are various other error values that could effectively
408 * mean that the xattr doesn't exist (e.g. -ERANGE is returned
409 * if the xattr name is too long), but the set of filesystems
410 * allowed as upper are limited to "normal" ones, where checking
411 * for the above two errors is sufficient.
413 err
= vfs_removexattr(work
, XATTR_NAME_POSIX_ACL_DEFAULT
);
414 if (err
&& err
!= -ENODATA
&& err
!= -EOPNOTSUPP
)
417 err
= vfs_removexattr(work
, XATTR_NAME_POSIX_ACL_ACCESS
);
418 if (err
&& err
!= -ENODATA
&& err
!= -EOPNOTSUPP
)
421 /* Clear any inherited mode bits */
422 inode_lock(work
->d_inode
);
423 err
= notify_change(work
, &attr
, NULL
);
424 inode_unlock(work
->d_inode
);
440 static void ovl_unescape(char *s
)
453 static int ovl_mount_dir_noesc(const char *name
, struct path
*path
)
458 pr_err("overlayfs: empty lowerdir\n");
461 err
= kern_path(name
, LOOKUP_FOLLOW
, path
);
463 pr_err("overlayfs: failed to resolve '%s': %i\n", name
, err
);
467 if (ovl_dentry_weird(path
->dentry
)) {
468 pr_err("overlayfs: filesystem on '%s' not supported\n", name
);
471 if (!d_is_dir(path
->dentry
)) {
472 pr_err("overlayfs: '%s' not a directory\n", name
);
483 static int ovl_mount_dir(const char *name
, struct path
*path
)
486 char *tmp
= kstrdup(name
, GFP_KERNEL
);
490 err
= ovl_mount_dir_noesc(tmp
, path
);
493 if (ovl_dentry_remote(path
->dentry
)) {
494 pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n",
504 static int ovl_check_namelen(struct path
*path
, struct ovl_fs
*ofs
,
507 struct kstatfs statfs
;
508 int err
= vfs_statfs(path
, &statfs
);
511 pr_err("overlayfs: statfs failed on '%s'\n", name
);
513 ofs
->namelen
= max(ofs
->namelen
, statfs
.f_namelen
);
518 static int ovl_lower_dir(const char *name
, struct path
*path
,
519 struct ovl_fs
*ofs
, int *stack_depth
, bool *remote
)
523 err
= ovl_mount_dir_noesc(name
, path
);
527 err
= ovl_check_namelen(path
, ofs
, name
);
531 *stack_depth
= max(*stack_depth
, path
->mnt
->mnt_sb
->s_stack_depth
);
533 if (ovl_dentry_remote(path
->dentry
))
544 /* Workdir should not be subdir of upperdir and vice versa */
545 static bool ovl_workdir_ok(struct dentry
*workdir
, struct dentry
*upperdir
)
549 if (workdir
!= upperdir
) {
550 ok
= (lock_rename(workdir
, upperdir
) == NULL
);
551 unlock_rename(workdir
, upperdir
);
556 static unsigned int ovl_split_lowerdirs(char *str
)
558 unsigned int ctr
= 1;
561 for (s
= d
= str
;; s
++, d
++) {
564 } else if (*s
== ':') {
576 static int __maybe_unused
577 ovl_posix_acl_xattr_get(const struct xattr_handler
*handler
,
578 struct dentry
*dentry
, struct inode
*inode
,
579 const char *name
, void *buffer
, size_t size
)
581 return ovl_xattr_get(dentry
, handler
->name
, buffer
, size
);
584 static int __maybe_unused
585 ovl_posix_acl_xattr_set(const struct xattr_handler
*handler
,
586 struct dentry
*dentry
, struct inode
*inode
,
587 const char *name
, const void *value
,
588 size_t size
, int flags
)
590 struct dentry
*workdir
= ovl_workdir(dentry
);
591 struct inode
*realinode
= ovl_inode_real(inode
, NULL
);
592 struct posix_acl
*acl
= NULL
;
595 /* Check that everything is OK before copy-up */
597 acl
= posix_acl_from_xattr(&init_user_ns
, value
, size
);
602 if (!IS_POSIXACL(d_inode(workdir
)))
603 goto out_acl_release
;
604 if (!realinode
->i_op
->set_acl
)
605 goto out_acl_release
;
606 if (handler
->flags
== ACL_TYPE_DEFAULT
&& !S_ISDIR(inode
->i_mode
)) {
607 err
= acl
? -EACCES
: 0;
608 goto out_acl_release
;
611 if (!inode_owner_or_capable(inode
))
612 goto out_acl_release
;
614 posix_acl_release(acl
);
617 * Check if sgid bit needs to be cleared (actual setacl operation will
618 * be done with mounter's capabilities and so that won't do it for us).
620 if (unlikely(inode
->i_mode
& S_ISGID
) &&
621 handler
->flags
== ACL_TYPE_ACCESS
&&
622 !in_group_p(inode
->i_gid
) &&
623 !capable_wrt_inode_uidgid(inode
, CAP_FSETID
)) {
624 struct iattr iattr
= { .ia_valid
= ATTR_KILL_SGID
};
626 err
= ovl_setattr(dentry
, &iattr
);
631 err
= ovl_xattr_set(dentry
, handler
->name
, value
, size
, flags
);
633 ovl_copyattr(ovl_inode_real(inode
, NULL
), inode
);
638 posix_acl_release(acl
);
642 static int ovl_own_xattr_get(const struct xattr_handler
*handler
,
643 struct dentry
*dentry
, struct inode
*inode
,
644 const char *name
, void *buffer
, size_t size
)
649 static int ovl_own_xattr_set(const struct xattr_handler
*handler
,
650 struct dentry
*dentry
, struct inode
*inode
,
651 const char *name
, const void *value
,
652 size_t size
, int flags
)
657 static int ovl_other_xattr_get(const struct xattr_handler
*handler
,
658 struct dentry
*dentry
, struct inode
*inode
,
659 const char *name
, void *buffer
, size_t size
)
661 return ovl_xattr_get(dentry
, name
, buffer
, size
);
664 static int ovl_other_xattr_set(const struct xattr_handler
*handler
,
665 struct dentry
*dentry
, struct inode
*inode
,
666 const char *name
, const void *value
,
667 size_t size
, int flags
)
669 return ovl_xattr_set(dentry
, name
, value
, size
, flags
);
672 static const struct xattr_handler __maybe_unused
673 ovl_posix_acl_access_xattr_handler
= {
674 .name
= XATTR_NAME_POSIX_ACL_ACCESS
,
675 .flags
= ACL_TYPE_ACCESS
,
676 .get
= ovl_posix_acl_xattr_get
,
677 .set
= ovl_posix_acl_xattr_set
,
680 static const struct xattr_handler __maybe_unused
681 ovl_posix_acl_default_xattr_handler
= {
682 .name
= XATTR_NAME_POSIX_ACL_DEFAULT
,
683 .flags
= ACL_TYPE_DEFAULT
,
684 .get
= ovl_posix_acl_xattr_get
,
685 .set
= ovl_posix_acl_xattr_set
,
688 static const struct xattr_handler ovl_own_xattr_handler
= {
689 .prefix
= OVL_XATTR_PREFIX
,
690 .get
= ovl_own_xattr_get
,
691 .set
= ovl_own_xattr_set
,
694 static const struct xattr_handler ovl_other_xattr_handler
= {
695 .prefix
= "", /* catch all */
696 .get
= ovl_other_xattr_get
,
697 .set
= ovl_other_xattr_set
,
700 static const struct xattr_handler
*ovl_xattr_handlers
[] = {
701 #ifdef CONFIG_FS_POSIX_ACL
702 &ovl_posix_acl_access_xattr_handler
,
703 &ovl_posix_acl_default_xattr_handler
,
705 &ovl_own_xattr_handler
,
706 &ovl_other_xattr_handler
,
710 static int ovl_fill_super(struct super_block
*sb
, void *data
, int silent
)
712 struct path upperpath
= { NULL
, NULL
};
713 struct path workpath
= { NULL
, NULL
};
714 struct dentry
*root_dentry
;
715 struct inode
*realinode
;
716 struct ovl_entry
*oe
;
718 struct path
*stack
= NULL
;
721 unsigned int numlower
;
722 unsigned int stacklen
= 0;
729 ufs
= kzalloc(sizeof(struct ovl_fs
), GFP_KERNEL
);
733 init_waitqueue_head(&ufs
->copyup_wq
);
734 ufs
->config
.redirect_dir
= ovl_redirect_dir_def
;
735 err
= ovl_parse_opt((char *) data
, &ufs
->config
);
737 goto out_free_config
;
740 if (!ufs
->config
.lowerdir
) {
742 pr_err("overlayfs: missing 'lowerdir'\n");
743 goto out_free_config
;
746 sb
->s_stack_depth
= 0;
747 sb
->s_maxbytes
= MAX_LFS_FILESIZE
;
748 if (ufs
->config
.upperdir
) {
749 if (!ufs
->config
.workdir
) {
750 pr_err("overlayfs: missing 'workdir'\n");
751 goto out_free_config
;
754 err
= ovl_mount_dir(ufs
->config
.upperdir
, &upperpath
);
756 goto out_free_config
;
758 /* Upper fs should not be r/o */
759 if (upperpath
.mnt
->mnt_sb
->s_flags
& MS_RDONLY
) {
760 pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n");
762 goto out_put_upperpath
;
765 err
= ovl_check_namelen(&upperpath
, ufs
, ufs
->config
.upperdir
);
767 goto out_put_upperpath
;
769 err
= ovl_mount_dir(ufs
->config
.workdir
, &workpath
);
771 goto out_put_upperpath
;
774 if (upperpath
.mnt
!= workpath
.mnt
) {
775 pr_err("overlayfs: workdir and upperdir must reside under the same mount\n");
776 goto out_put_workpath
;
778 if (!ovl_workdir_ok(workpath
.dentry
, upperpath
.dentry
)) {
779 pr_err("overlayfs: workdir and upperdir must be separate subtrees\n");
780 goto out_put_workpath
;
782 sb
->s_stack_depth
= upperpath
.mnt
->mnt_sb
->s_stack_depth
;
785 lowertmp
= kstrdup(ufs
->config
.lowerdir
, GFP_KERNEL
);
787 goto out_put_workpath
;
790 stacklen
= ovl_split_lowerdirs(lowertmp
);
791 if (stacklen
> OVL_MAX_STACK
) {
792 pr_err("overlayfs: too many lower directories, limit is %d\n",
794 goto out_free_lowertmp
;
795 } else if (!ufs
->config
.upperdir
&& stacklen
== 1) {
796 pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
797 goto out_free_lowertmp
;
801 stack
= kcalloc(stacklen
, sizeof(struct path
), GFP_KERNEL
);
803 goto out_free_lowertmp
;
807 for (numlower
= 0; numlower
< stacklen
; numlower
++) {
808 err
= ovl_lower_dir(lower
, &stack
[numlower
], ufs
,
809 &sb
->s_stack_depth
, &remote
);
811 goto out_put_lowerpath
;
813 lower
= strchr(lower
, '\0') + 1;
818 if (sb
->s_stack_depth
> FILESYSTEM_MAX_STACK_DEPTH
) {
819 pr_err("overlayfs: maximum fs stacking depth exceeded\n");
820 goto out_put_lowerpath
;
823 if (ufs
->config
.upperdir
) {
824 ufs
->upper_mnt
= clone_private_mount(&upperpath
);
825 err
= PTR_ERR(ufs
->upper_mnt
);
826 if (IS_ERR(ufs
->upper_mnt
)) {
827 pr_err("overlayfs: failed to clone upperpath\n");
828 goto out_put_lowerpath
;
830 /* Don't inherit atime flags */
831 ufs
->upper_mnt
->mnt_flags
&= ~(MNT_NOATIME
| MNT_NODIRATIME
| MNT_RELATIME
);
833 sb
->s_time_gran
= ufs
->upper_mnt
->mnt_sb
->s_time_gran
;
835 ufs
->workdir
= ovl_workdir_create(ufs
->upper_mnt
, workpath
.dentry
);
836 err
= PTR_ERR(ufs
->workdir
);
837 if (IS_ERR(ufs
->workdir
)) {
838 pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n",
839 ufs
->config
.workdir
, OVL_WORKDIR_NAME
, -err
);
840 sb
->s_flags
|= MS_RDONLY
;
845 * Upper should support d_type, else whiteouts are visible.
846 * Given workdir and upper are on same fs, we can do
847 * iterate_dir() on workdir. This check requires successful
848 * creation of workdir in previous step.
853 err
= ovl_check_d_type_supported(&workpath
);
855 goto out_put_workdir
;
858 * We allowed this configuration and don't want to
859 * break users over kernel upgrade. So warn instead
863 pr_warn("overlayfs: upper fs needs to support d_type.\n");
865 /* Check if upper/work fs supports O_TMPFILE */
866 temp
= ovl_do_tmpfile(ufs
->workdir
, S_IFREG
| 0);
867 ufs
->tmpfile
= !IS_ERR(temp
);
871 pr_warn("overlayfs: upper fs does not support tmpfile.\n");
876 ufs
->lower_mnt
= kcalloc(numlower
, sizeof(struct vfsmount
*), GFP_KERNEL
);
877 if (ufs
->lower_mnt
== NULL
)
878 goto out_put_workdir
;
879 for (i
= 0; i
< numlower
; i
++) {
880 struct vfsmount
*mnt
= clone_private_mount(&stack
[i
]);
884 pr_err("overlayfs: failed to clone lowerpath\n");
885 goto out_put_lower_mnt
;
888 * Make lower_mnt R/O. That way fchmod/fchown on lower file
889 * will fail instead of modifying lower fs.
891 mnt
->mnt_flags
|= MNT_READONLY
| MNT_NOATIME
;
893 ufs
->lower_mnt
[ufs
->numlower
] = mnt
;
897 /* If the upper fs is nonexistent, we mark overlayfs r/o too */
899 sb
->s_flags
|= MS_RDONLY
;
902 sb
->s_d_op
= &ovl_reval_dentry_operations
;
904 sb
->s_d_op
= &ovl_dentry_operations
;
906 ufs
->creator_cred
= cred
= prepare_creds();
908 goto out_put_lower_mnt
;
910 /* Never override disk quota limits or use reserved space */
911 cap_lower(cred
->cap_effective
, CAP_SYS_RESOURCE
);
914 oe
= ovl_alloc_entry(numlower
);
918 sb
->s_magic
= OVERLAYFS_SUPER_MAGIC
;
919 sb
->s_op
= &ovl_super_operations
;
920 sb
->s_xattr
= ovl_xattr_handlers
;
922 sb
->s_flags
|= MS_POSIXACL
| MS_NOREMOTELOCK
;
924 root_dentry
= d_make_root(ovl_new_inode(sb
, S_IFDIR
, 0));
928 mntput(upperpath
.mnt
);
929 for (i
= 0; i
< numlower
; i
++)
930 mntput(stack
[i
].mnt
);
934 oe
->__upperdentry
= upperpath
.dentry
;
935 for (i
= 0; i
< numlower
; i
++) {
936 oe
->lowerstack
[i
].dentry
= stack
[i
].dentry
;
937 oe
->lowerstack
[i
].mnt
= ufs
->lower_mnt
[i
];
941 root_dentry
->d_fsdata
= oe
;
943 realinode
= d_inode(ovl_dentry_real(root_dentry
));
944 ovl_inode_init(d_inode(root_dentry
), realinode
, !!upperpath
.dentry
);
945 ovl_copyattr(realinode
, d_inode(root_dentry
));
947 sb
->s_root
= root_dentry
;
954 put_cred(ufs
->creator_cred
);
956 for (i
= 0; i
< ufs
->numlower
; i
++)
957 mntput(ufs
->lower_mnt
[i
]);
958 kfree(ufs
->lower_mnt
);
961 mntput(ufs
->upper_mnt
);
963 for (i
= 0; i
< numlower
; i
++)
971 path_put(&upperpath
);
973 kfree(ufs
->config
.lowerdir
);
974 kfree(ufs
->config
.upperdir
);
975 kfree(ufs
->config
.workdir
);
981 static struct dentry
*ovl_mount(struct file_system_type
*fs_type
, int flags
,
982 const char *dev_name
, void *raw_data
)
984 return mount_nodev(fs_type
, flags
, raw_data
, ovl_fill_super
);
987 static struct file_system_type ovl_fs_type
= {
988 .owner
= THIS_MODULE
,
991 .kill_sb
= kill_anon_super
,
993 MODULE_ALIAS_FS("overlay");
995 static int __init
ovl_init(void)
997 return register_filesystem(&ovl_fs_type
);
1000 static void __exit
ovl_exit(void)
1002 unregister_filesystem(&ovl_fs_type
);
1005 module_init(ovl_init
);
1006 module_exit(ovl_exit
);