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.
11 #include <linux/namei.h>
12 #include <linux/xattr.h>
13 #include <linux/security.h>
14 #include <linux/mount.h>
15 #include <linux/slab.h>
16 #include <linux/parser.h>
17 #include <linux/module.h>
18 #include <linux/sched.h>
19 #include <linux/statfs.h>
20 #include <linux/seq_file.h>
21 #include "overlayfs.h"
23 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
24 MODULE_DESCRIPTION("Overlay filesystem");
25 MODULE_LICENSE("GPL");
27 #define OVERLAYFS_SUPER_MAGIC 0x794c7630
35 /* private information held for overlayfs's superblock */
37 struct vfsmount
*upper_mnt
;
39 struct vfsmount
**lower_mnt
;
40 struct dentry
*workdir
;
42 /* pathnames of lower and upper dirs, for show_options */
43 struct ovl_config config
;
48 /* private information held for every overlayfs dentry */
50 struct dentry
*__upperdentry
;
51 struct ovl_dir_cache
*cache
;
60 struct path lowerstack
[];
63 #define OVL_MAX_STACK 500
65 static struct dentry
*__ovl_dentry_lower(struct ovl_entry
*oe
)
67 return oe
->numlower
? oe
->lowerstack
[0].dentry
: NULL
;
70 enum ovl_path_type
ovl_path_type(struct dentry
*dentry
)
72 struct ovl_entry
*oe
= dentry
->d_fsdata
;
73 enum ovl_path_type type
= 0;
75 if (oe
->__upperdentry
) {
76 type
= __OVL_PATH_UPPER
;
79 if (S_ISDIR(dentry
->d_inode
->i_mode
))
80 type
|= __OVL_PATH_MERGE
;
81 } else if (!oe
->opaque
) {
82 type
|= __OVL_PATH_PURE
;
86 type
|= __OVL_PATH_MERGE
;
91 static struct dentry
*ovl_upperdentry_dereference(struct ovl_entry
*oe
)
93 return lockless_dereference(oe
->__upperdentry
);
96 void ovl_path_upper(struct dentry
*dentry
, struct path
*path
)
98 struct ovl_fs
*ofs
= dentry
->d_sb
->s_fs_info
;
99 struct ovl_entry
*oe
= dentry
->d_fsdata
;
101 path
->mnt
= ofs
->upper_mnt
;
102 path
->dentry
= ovl_upperdentry_dereference(oe
);
105 enum ovl_path_type
ovl_path_real(struct dentry
*dentry
, struct path
*path
)
107 enum ovl_path_type type
= ovl_path_type(dentry
);
109 if (!OVL_TYPE_UPPER(type
))
110 ovl_path_lower(dentry
, path
);
112 ovl_path_upper(dentry
, path
);
117 struct dentry
*ovl_dentry_upper(struct dentry
*dentry
)
119 struct ovl_entry
*oe
= dentry
->d_fsdata
;
121 return ovl_upperdentry_dereference(oe
);
124 struct dentry
*ovl_dentry_lower(struct dentry
*dentry
)
126 struct ovl_entry
*oe
= dentry
->d_fsdata
;
128 return __ovl_dentry_lower(oe
);
131 struct dentry
*ovl_dentry_real(struct dentry
*dentry
)
133 struct ovl_entry
*oe
= dentry
->d_fsdata
;
134 struct dentry
*realdentry
;
136 realdentry
= ovl_upperdentry_dereference(oe
);
138 realdentry
= __ovl_dentry_lower(oe
);
143 struct dentry
*ovl_entry_real(struct ovl_entry
*oe
, bool *is_upper
)
145 struct dentry
*realdentry
;
147 realdentry
= ovl_upperdentry_dereference(oe
);
151 realdentry
= __ovl_dentry_lower(oe
);
157 struct ovl_dir_cache
*ovl_dir_cache(struct dentry
*dentry
)
159 struct ovl_entry
*oe
= dentry
->d_fsdata
;
164 void ovl_set_dir_cache(struct dentry
*dentry
, struct ovl_dir_cache
*cache
)
166 struct ovl_entry
*oe
= dentry
->d_fsdata
;
171 void ovl_path_lower(struct dentry
*dentry
, struct path
*path
)
173 struct ovl_entry
*oe
= dentry
->d_fsdata
;
175 *path
= oe
->numlower
? oe
->lowerstack
[0] : (struct path
) { NULL
, NULL
};
178 int ovl_want_write(struct dentry
*dentry
)
180 struct ovl_fs
*ofs
= dentry
->d_sb
->s_fs_info
;
181 return mnt_want_write(ofs
->upper_mnt
);
184 void ovl_drop_write(struct dentry
*dentry
)
186 struct ovl_fs
*ofs
= dentry
->d_sb
->s_fs_info
;
187 mnt_drop_write(ofs
->upper_mnt
);
190 struct dentry
*ovl_workdir(struct dentry
*dentry
)
192 struct ovl_fs
*ofs
= dentry
->d_sb
->s_fs_info
;
196 bool ovl_dentry_is_opaque(struct dentry
*dentry
)
198 struct ovl_entry
*oe
= dentry
->d_fsdata
;
202 void ovl_dentry_set_opaque(struct dentry
*dentry
, bool opaque
)
204 struct ovl_entry
*oe
= dentry
->d_fsdata
;
208 void ovl_dentry_update(struct dentry
*dentry
, struct dentry
*upperdentry
)
210 struct ovl_entry
*oe
= dentry
->d_fsdata
;
212 WARN_ON(!mutex_is_locked(&upperdentry
->d_parent
->d_inode
->i_mutex
));
213 WARN_ON(oe
->__upperdentry
);
214 BUG_ON(!upperdentry
->d_inode
);
216 * Make sure upperdentry is consistent before making it visible to
217 * ovl_upperdentry_dereference().
220 oe
->__upperdentry
= upperdentry
;
223 void ovl_dentry_version_inc(struct dentry
*dentry
)
225 struct ovl_entry
*oe
= dentry
->d_fsdata
;
227 WARN_ON(!mutex_is_locked(&dentry
->d_inode
->i_mutex
));
231 u64
ovl_dentry_version_get(struct dentry
*dentry
)
233 struct ovl_entry
*oe
= dentry
->d_fsdata
;
235 WARN_ON(!mutex_is_locked(&dentry
->d_inode
->i_mutex
));
239 bool ovl_is_whiteout(struct dentry
*dentry
)
241 struct inode
*inode
= dentry
->d_inode
;
243 return inode
&& IS_WHITEOUT(inode
);
246 static bool ovl_is_opaquedir(struct dentry
*dentry
)
250 struct inode
*inode
= dentry
->d_inode
;
252 if (!S_ISDIR(inode
->i_mode
) || !inode
->i_op
->getxattr
)
255 res
= inode
->i_op
->getxattr(dentry
, OVL_XATTR_OPAQUE
, &val
, 1);
256 if (res
== 1 && val
== 'y')
262 static void ovl_dentry_release(struct dentry
*dentry
)
264 struct ovl_entry
*oe
= dentry
->d_fsdata
;
269 dput(oe
->__upperdentry
);
270 for (i
= 0; i
< oe
->numlower
; i
++)
271 dput(oe
->lowerstack
[i
].dentry
);
276 static const struct dentry_operations ovl_dentry_operations
= {
277 .d_release
= ovl_dentry_release
,
280 static struct ovl_entry
*ovl_alloc_entry(unsigned int numlower
)
282 size_t size
= offsetof(struct ovl_entry
, lowerstack
[numlower
]);
283 struct ovl_entry
*oe
= kzalloc(size
, GFP_KERNEL
);
286 oe
->numlower
= numlower
;
291 static inline struct dentry
*ovl_lookup_real(struct dentry
*dir
,
294 struct dentry
*dentry
;
296 mutex_lock(&dir
->d_inode
->i_mutex
);
297 dentry
= lookup_one_len(name
->name
, dir
, name
->len
);
298 mutex_unlock(&dir
->d_inode
->i_mutex
);
300 if (IS_ERR(dentry
)) {
301 if (PTR_ERR(dentry
) == -ENOENT
)
303 } else if (!dentry
->d_inode
) {
311 * Returns next layer in stack starting from top.
312 * Returns -1 if this is the last layer.
314 int ovl_path_next(int idx
, struct dentry
*dentry
, struct path
*path
)
316 struct ovl_entry
*oe
= dentry
->d_fsdata
;
320 ovl_path_upper(dentry
, path
);
322 return oe
->numlower
? 1 : -1;
325 BUG_ON(idx
> oe
->numlower
);
326 *path
= oe
->lowerstack
[idx
- 1];
328 return (idx
< oe
->numlower
) ? idx
+ 1 : -1;
331 struct dentry
*ovl_lookup(struct inode
*dir
, struct dentry
*dentry
,
334 struct ovl_entry
*oe
;
335 struct ovl_entry
*poe
= dentry
->d_parent
->d_fsdata
;
336 struct path
*stack
= NULL
;
337 struct dentry
*upperdir
, *upperdentry
= NULL
;
338 unsigned int ctr
= 0;
339 struct inode
*inode
= NULL
;
340 bool upperopaque
= false;
341 struct dentry
*this, *prev
= NULL
;
345 upperdir
= ovl_upperdentry_dereference(poe
);
347 this = ovl_lookup_real(upperdir
, &dentry
->d_name
);
353 if (ovl_is_whiteout(this)) {
357 } else if (poe
->numlower
&& ovl_is_opaquedir(this)) {
361 upperdentry
= prev
= this;
364 if (!upperopaque
&& poe
->numlower
) {
366 stack
= kcalloc(poe
->numlower
, sizeof(struct path
), GFP_KERNEL
);
371 for (i
= 0; !upperopaque
&& i
< poe
->numlower
; i
++) {
373 struct path lowerpath
= poe
->lowerstack
[i
];
375 this = ovl_lookup_real(lowerpath
.dentry
, &dentry
->d_name
);
379 * If it's positive, then treat ENAMETOOLONG as ENOENT.
381 if (err
== -ENAMETOOLONG
&& (upperdentry
|| ctr
))
387 if (ovl_is_whiteout(this)) {
392 * Only makes sense to check opaque dir if this is not the
395 if (i
< poe
->numlower
- 1 && ovl_is_opaquedir(this))
398 if (prev
&& (!S_ISDIR(prev
->d_inode
->i_mode
) ||
399 !S_ISDIR(this->d_inode
->i_mode
))) {
401 * FIXME: check for upper-opaqueness maybe better done
404 if (prev
== upperdentry
)
410 * If this is a non-directory then stop here.
412 if (!S_ISDIR(this->d_inode
->i_mode
))
415 stack
[ctr
].dentry
= this;
416 stack
[ctr
].mnt
= lowerpath
.mnt
;
423 oe
= ovl_alloc_entry(ctr
);
428 if (upperdentry
|| ctr
) {
429 struct dentry
*realdentry
;
431 realdentry
= upperdentry
? upperdentry
: stack
[0].dentry
;
434 inode
= ovl_new_inode(dentry
->d_sb
, realdentry
->d_inode
->i_mode
,
438 ovl_copyattr(realdentry
->d_inode
, inode
);
441 oe
->opaque
= upperopaque
;
442 oe
->__upperdentry
= upperdentry
;
443 memcpy(oe
->lowerstack
, stack
, sizeof(struct path
) * ctr
);
445 dentry
->d_fsdata
= oe
;
446 d_add(dentry
, inode
);
453 for (i
= 0; i
< ctr
; i
++)
454 dput(stack
[i
].dentry
);
462 struct file
*ovl_path_open(struct path
*path
, int flags
)
464 return dentry_open(path
, flags
, current_cred());
467 static void ovl_put_super(struct super_block
*sb
)
469 struct ovl_fs
*ufs
= sb
->s_fs_info
;
473 mntput(ufs
->upper_mnt
);
474 for (i
= 0; i
< ufs
->numlower
; i
++)
475 mntput(ufs
->lower_mnt
[i
]);
477 kfree(ufs
->config
.lowerdir
);
478 kfree(ufs
->config
.upperdir
);
479 kfree(ufs
->config
.workdir
);
485 * @sb: The overlayfs super block
486 * @buf: The struct kstatfs to fill in with stats
488 * Get the filesystem statistics. As writes always target the upper layer
489 * filesystem pass the statfs to the upper filesystem (if it exists)
491 static int ovl_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
493 struct ovl_fs
*ofs
= dentry
->d_sb
->s_fs_info
;
494 struct dentry
*root_dentry
= dentry
->d_sb
->s_root
;
498 ovl_path_real(root_dentry
, &path
);
500 err
= vfs_statfs(&path
, buf
);
502 buf
->f_namelen
= max(buf
->f_namelen
, ofs
->lower_namelen
);
503 buf
->f_type
= OVERLAYFS_SUPER_MAGIC
;
512 * Prints the mount options for a given superblock.
513 * Returns zero; does not fail.
515 static int ovl_show_options(struct seq_file
*m
, struct dentry
*dentry
)
517 struct super_block
*sb
= dentry
->d_sb
;
518 struct ovl_fs
*ufs
= sb
->s_fs_info
;
520 seq_printf(m
, ",lowerdir=%s", ufs
->config
.lowerdir
);
521 if (ufs
->config
.upperdir
) {
522 seq_printf(m
, ",upperdir=%s", ufs
->config
.upperdir
);
523 seq_printf(m
, ",workdir=%s", ufs
->config
.workdir
);
528 static int ovl_remount(struct super_block
*sb
, int *flags
, char *data
)
530 struct ovl_fs
*ufs
= sb
->s_fs_info
;
532 if (!(*flags
& MS_RDONLY
) && (!ufs
->upper_mnt
|| !ufs
->workdir
))
538 static const struct super_operations ovl_super_operations
= {
539 .put_super
= ovl_put_super
,
540 .statfs
= ovl_statfs
,
541 .show_options
= ovl_show_options
,
542 .remount_fs
= ovl_remount
,
552 static const match_table_t ovl_tokens
= {
553 {OPT_LOWERDIR
, "lowerdir=%s"},
554 {OPT_UPPERDIR
, "upperdir=%s"},
555 {OPT_WORKDIR
, "workdir=%s"},
559 static char *ovl_next_opt(char **s
)
567 for (p
= sbegin
; *p
; p
++) {
572 } else if (*p
== ',') {
582 static int ovl_parse_opt(char *opt
, struct ovl_config
*config
)
586 while ((p
= ovl_next_opt(&opt
)) != NULL
) {
588 substring_t args
[MAX_OPT_ARGS
];
593 token
= match_token(p
, ovl_tokens
, args
);
596 kfree(config
->upperdir
);
597 config
->upperdir
= match_strdup(&args
[0]);
598 if (!config
->upperdir
)
603 kfree(config
->lowerdir
);
604 config
->lowerdir
= match_strdup(&args
[0]);
605 if (!config
->lowerdir
)
610 kfree(config
->workdir
);
611 config
->workdir
= match_strdup(&args
[0]);
612 if (!config
->workdir
)
617 pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p
);
622 /* Workdir is useless in non-upper mount */
623 if (!config
->upperdir
&& config
->workdir
) {
624 pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
626 kfree(config
->workdir
);
627 config
->workdir
= NULL
;
633 #define OVL_WORKDIR_NAME "work"
635 static struct dentry
*ovl_workdir_create(struct vfsmount
*mnt
,
636 struct dentry
*dentry
)
638 struct inode
*dir
= dentry
->d_inode
;
641 bool retried
= false;
643 err
= mnt_want_write(mnt
);
647 mutex_lock_nested(&dir
->i_mutex
, I_MUTEX_PARENT
);
649 work
= lookup_one_len(OVL_WORKDIR_NAME
, dentry
,
650 strlen(OVL_WORKDIR_NAME
));
653 struct kstat stat
= {
663 ovl_cleanup(dir
, work
);
668 err
= ovl_create_real(dir
, work
, &stat
, NULL
, NULL
, true);
673 mutex_unlock(&dir
->i_mutex
);
684 static void ovl_unescape(char *s
)
697 static bool ovl_is_allowed_fs_type(struct dentry
*root
)
699 const struct dentry_operations
*dop
= root
->d_op
;
703 * - automount filesystems
704 * - filesystems with revalidate (FIXME for lower layer)
705 * - filesystems with case insensitive names
708 (dop
->d_manage
|| dop
->d_automount
||
709 dop
->d_revalidate
|| dop
->d_weak_revalidate
||
710 dop
->d_compare
|| dop
->d_hash
)) {
716 static int ovl_mount_dir_noesc(const char *name
, struct path
*path
)
721 pr_err("overlayfs: empty lowerdir\n");
724 err
= kern_path(name
, LOOKUP_FOLLOW
, path
);
726 pr_err("overlayfs: failed to resolve '%s': %i\n", name
, err
);
730 if (!ovl_is_allowed_fs_type(path
->dentry
)) {
731 pr_err("overlayfs: filesystem on '%s' not supported\n", name
);
734 if (!S_ISDIR(path
->dentry
->d_inode
->i_mode
)) {
735 pr_err("overlayfs: '%s' not a directory\n", name
);
746 static int ovl_mount_dir(const char *name
, struct path
*path
)
749 char *tmp
= kstrdup(name
, GFP_KERNEL
);
753 err
= ovl_mount_dir_noesc(tmp
, path
);
759 static int ovl_lower_dir(const char *name
, struct path
*path
, long *namelen
,
763 struct kstatfs statfs
;
765 err
= ovl_mount_dir_noesc(name
, path
);
769 err
= vfs_statfs(path
, &statfs
);
771 pr_err("overlayfs: statfs failed on '%s'\n", name
);
774 *namelen
= max(*namelen
, statfs
.f_namelen
);
775 *stack_depth
= max(*stack_depth
, path
->mnt
->mnt_sb
->s_stack_depth
);
785 /* Workdir should not be subdir of upperdir and vice versa */
786 static bool ovl_workdir_ok(struct dentry
*workdir
, struct dentry
*upperdir
)
790 if (workdir
!= upperdir
) {
791 ok
= (lock_rename(workdir
, upperdir
) == NULL
);
792 unlock_rename(workdir
, upperdir
);
797 static unsigned int ovl_split_lowerdirs(char *str
)
799 unsigned int ctr
= 1;
802 for (s
= d
= str
;; s
++, d
++) {
805 } else if (*s
== ':') {
817 static int ovl_fill_super(struct super_block
*sb
, void *data
, int silent
)
819 struct path upperpath
= { NULL
, NULL
};
820 struct path workpath
= { NULL
, NULL
};
821 struct dentry
*root_dentry
;
822 struct ovl_entry
*oe
;
824 struct path
*stack
= NULL
;
827 unsigned int numlower
;
828 unsigned int stacklen
= 0;
833 ufs
= kzalloc(sizeof(struct ovl_fs
), GFP_KERNEL
);
837 err
= ovl_parse_opt((char *) data
, &ufs
->config
);
839 goto out_free_config
;
842 if (!ufs
->config
.lowerdir
) {
843 pr_err("overlayfs: missing 'lowerdir'\n");
844 goto out_free_config
;
847 sb
->s_stack_depth
= 0;
848 if (ufs
->config
.upperdir
) {
849 if (!ufs
->config
.workdir
) {
850 pr_err("overlayfs: missing 'workdir'\n");
851 goto out_free_config
;
854 err
= ovl_mount_dir(ufs
->config
.upperdir
, &upperpath
);
856 goto out_free_config
;
858 /* Upper fs should not be r/o */
859 if (upperpath
.mnt
->mnt_sb
->s_flags
& MS_RDONLY
) {
860 pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n");
862 goto out_put_upperpath
;
865 err
= ovl_mount_dir(ufs
->config
.workdir
, &workpath
);
867 goto out_put_upperpath
;
870 if (upperpath
.mnt
!= workpath
.mnt
) {
871 pr_err("overlayfs: workdir and upperdir must reside under the same mount\n");
872 goto out_put_workpath
;
874 if (!ovl_workdir_ok(workpath
.dentry
, upperpath
.dentry
)) {
875 pr_err("overlayfs: workdir and upperdir must be separate subtrees\n");
876 goto out_put_workpath
;
878 sb
->s_stack_depth
= upperpath
.mnt
->mnt_sb
->s_stack_depth
;
881 lowertmp
= kstrdup(ufs
->config
.lowerdir
, GFP_KERNEL
);
883 goto out_put_workpath
;
886 stacklen
= ovl_split_lowerdirs(lowertmp
);
887 if (stacklen
> OVL_MAX_STACK
) {
888 pr_err("overlayfs: too many lower directries, limit is %d\n",
890 goto out_free_lowertmp
;
891 } else if (!ufs
->config
.upperdir
&& stacklen
== 1) {
892 pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
893 goto out_free_lowertmp
;
896 stack
= kcalloc(stacklen
, sizeof(struct path
), GFP_KERNEL
);
898 goto out_free_lowertmp
;
901 for (numlower
= 0; numlower
< stacklen
; numlower
++) {
902 err
= ovl_lower_dir(lower
, &stack
[numlower
],
903 &ufs
->lower_namelen
, &sb
->s_stack_depth
);
905 goto out_put_lowerpath
;
907 lower
= strchr(lower
, '\0') + 1;
912 if (sb
->s_stack_depth
> FILESYSTEM_MAX_STACK_DEPTH
) {
913 pr_err("overlayfs: maximum fs stacking depth exceeded\n");
914 goto out_put_lowerpath
;
917 if (ufs
->config
.upperdir
) {
918 ufs
->upper_mnt
= clone_private_mount(&upperpath
);
919 err
= PTR_ERR(ufs
->upper_mnt
);
920 if (IS_ERR(ufs
->upper_mnt
)) {
921 pr_err("overlayfs: failed to clone upperpath\n");
922 goto out_put_lowerpath
;
925 ufs
->workdir
= ovl_workdir_create(ufs
->upper_mnt
, workpath
.dentry
);
926 err
= PTR_ERR(ufs
->workdir
);
927 if (IS_ERR(ufs
->workdir
)) {
928 pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n",
929 ufs
->config
.workdir
, OVL_WORKDIR_NAME
, -err
);
930 sb
->s_flags
|= MS_RDONLY
;
936 ufs
->lower_mnt
= kcalloc(numlower
, sizeof(struct vfsmount
*), GFP_KERNEL
);
937 if (ufs
->lower_mnt
== NULL
)
938 goto out_put_workdir
;
939 for (i
= 0; i
< numlower
; i
++) {
940 struct vfsmount
*mnt
= clone_private_mount(&stack
[i
]);
944 pr_err("overlayfs: failed to clone lowerpath\n");
945 goto out_put_lower_mnt
;
948 * Make lower_mnt R/O. That way fchmod/fchown on lower file
949 * will fail instead of modifying lower fs.
951 mnt
->mnt_flags
|= MNT_READONLY
;
953 ufs
->lower_mnt
[ufs
->numlower
] = mnt
;
957 /* If the upper fs is nonexistent, we mark overlayfs r/o too */
959 sb
->s_flags
|= MS_RDONLY
;
961 sb
->s_d_op
= &ovl_dentry_operations
;
964 oe
= ovl_alloc_entry(numlower
);
966 goto out_put_lower_mnt
;
968 root_dentry
= d_make_root(ovl_new_inode(sb
, S_IFDIR
, oe
));
972 mntput(upperpath
.mnt
);
973 for (i
= 0; i
< numlower
; i
++)
974 mntput(stack
[i
].mnt
);
978 oe
->__upperdentry
= upperpath
.dentry
;
979 for (i
= 0; i
< numlower
; i
++) {
980 oe
->lowerstack
[i
].dentry
= stack
[i
].dentry
;
981 oe
->lowerstack
[i
].mnt
= ufs
->lower_mnt
[i
];
984 root_dentry
->d_fsdata
= oe
;
986 sb
->s_magic
= OVERLAYFS_SUPER_MAGIC
;
987 sb
->s_op
= &ovl_super_operations
;
988 sb
->s_root
= root_dentry
;
996 for (i
= 0; i
< ufs
->numlower
; i
++)
997 mntput(ufs
->lower_mnt
[i
]);
998 kfree(ufs
->lower_mnt
);
1001 mntput(ufs
->upper_mnt
);
1003 for (i
= 0; i
< numlower
; i
++)
1004 path_put(&stack
[i
]);
1009 path_put(&workpath
);
1011 path_put(&upperpath
);
1013 kfree(ufs
->config
.lowerdir
);
1014 kfree(ufs
->config
.upperdir
);
1015 kfree(ufs
->config
.workdir
);
1021 static struct dentry
*ovl_mount(struct file_system_type
*fs_type
, int flags
,
1022 const char *dev_name
, void *raw_data
)
1024 return mount_nodev(fs_type
, flags
, raw_data
, ovl_fill_super
);
1027 static struct file_system_type ovl_fs_type
= {
1028 .owner
= THIS_MODULE
,
1031 .kill_sb
= kill_anon_super
,
1033 MODULE_ALIAS_FS("overlay");
1035 static int __init
ovl_init(void)
1037 return register_filesystem(&ovl_fs_type
);
1040 static void __exit
ovl_exit(void)
1042 unregister_filesystem(&ovl_fs_type
);
1045 module_init(ovl_init
);
1046 module_exit(ovl_exit
);