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 for (i
= 0; i
< oe
->numlower
; i
++)
45 dput(oe
->lowerstack
[i
].dentry
);
50 static int ovl_check_append_only(struct inode
*inode
, int flag
)
53 * This test was moot in vfs may_open() because overlay inode does
54 * not have the S_APPEND flag, so re-check on real upper inode
56 if (IS_APPEND(inode
)) {
57 if ((flag
& O_ACCMODE
) != O_RDONLY
&& !(flag
& O_APPEND
))
66 static struct dentry
*ovl_d_real(struct dentry
*dentry
,
67 const struct inode
*inode
,
68 unsigned int open_flags
)
73 if (!d_is_reg(dentry
)) {
74 if (!inode
|| inode
== d_inode(dentry
))
79 if (d_is_negative(dentry
))
83 err
= ovl_open_maybe_copy_up(dentry
, open_flags
);
88 real
= ovl_dentry_upper(dentry
);
89 if (real
&& (!inode
|| inode
== d_inode(real
))) {
91 err
= ovl_check_append_only(d_inode(real
), open_flags
);
98 real
= ovl_dentry_lower(dentry
);
102 /* Handle recursion */
103 real
= d_real(real
, inode
, open_flags
);
105 if (!inode
|| inode
== d_inode(real
))
108 WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry
,
109 inode
? inode
->i_sb
->s_id
: "NULL", inode
? inode
->i_ino
: 0);
113 static int ovl_dentry_revalidate(struct dentry
*dentry
, unsigned int flags
)
115 struct ovl_entry
*oe
= dentry
->d_fsdata
;
119 for (i
= 0; i
< oe
->numlower
; i
++) {
120 struct dentry
*d
= oe
->lowerstack
[i
].dentry
;
122 if (d
->d_flags
& DCACHE_OP_REVALIDATE
) {
123 ret
= d
->d_op
->d_revalidate(d
, flags
);
127 if (!(flags
& LOOKUP_RCU
))
136 static int ovl_dentry_weak_revalidate(struct dentry
*dentry
, unsigned int flags
)
138 struct ovl_entry
*oe
= dentry
->d_fsdata
;
142 for (i
= 0; i
< oe
->numlower
; i
++) {
143 struct dentry
*d
= oe
->lowerstack
[i
].dentry
;
145 if (d
->d_flags
& DCACHE_OP_WEAK_REVALIDATE
) {
146 ret
= d
->d_op
->d_weak_revalidate(d
, flags
);
154 static const struct dentry_operations ovl_dentry_operations
= {
155 .d_release
= ovl_dentry_release
,
156 .d_real
= ovl_d_real
,
159 static const struct dentry_operations ovl_reval_dentry_operations
= {
160 .d_release
= ovl_dentry_release
,
161 .d_real
= ovl_d_real
,
162 .d_revalidate
= ovl_dentry_revalidate
,
163 .d_weak_revalidate
= ovl_dentry_weak_revalidate
,
166 static struct kmem_cache
*ovl_inode_cachep
;
168 static struct inode
*ovl_alloc_inode(struct super_block
*sb
)
170 struct ovl_inode
*oi
= kmem_cache_alloc(ovl_inode_cachep
, GFP_KERNEL
);
173 oi
->__upperdentry
= NULL
;
176 return &oi
->vfs_inode
;
179 static void ovl_i_callback(struct rcu_head
*head
)
181 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
183 kmem_cache_free(ovl_inode_cachep
, OVL_I(inode
));
186 static void ovl_destroy_inode(struct inode
*inode
)
188 struct ovl_inode
*oi
= OVL_I(inode
);
190 dput(oi
->__upperdentry
);
193 call_rcu(&inode
->i_rcu
, ovl_i_callback
);
196 static void ovl_put_super(struct super_block
*sb
)
198 struct ovl_fs
*ufs
= sb
->s_fs_info
;
202 mntput(ufs
->upper_mnt
);
203 for (i
= 0; i
< ufs
->numlower
; i
++)
204 mntput(ufs
->lower_mnt
[i
]);
205 kfree(ufs
->lower_mnt
);
207 kfree(ufs
->config
.lowerdir
);
208 kfree(ufs
->config
.upperdir
);
209 kfree(ufs
->config
.workdir
);
210 put_cred(ufs
->creator_cred
);
214 static int ovl_sync_fs(struct super_block
*sb
, int wait
)
216 struct ovl_fs
*ufs
= sb
->s_fs_info
;
217 struct super_block
*upper_sb
;
222 upper_sb
= ufs
->upper_mnt
->mnt_sb
;
223 if (!upper_sb
->s_op
->sync_fs
)
226 /* real inodes have already been synced by sync_filesystem(ovl_sb) */
227 down_read(&upper_sb
->s_umount
);
228 ret
= upper_sb
->s_op
->sync_fs(upper_sb
, wait
);
229 up_read(&upper_sb
->s_umount
);
235 * @sb: The overlayfs super block
236 * @buf: The struct kstatfs to fill in with stats
238 * Get the filesystem statistics. As writes always target the upper layer
239 * filesystem pass the statfs to the upper filesystem (if it exists)
241 static int ovl_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
243 struct ovl_fs
*ofs
= dentry
->d_sb
->s_fs_info
;
244 struct dentry
*root_dentry
= dentry
->d_sb
->s_root
;
248 ovl_path_real(root_dentry
, &path
);
250 err
= vfs_statfs(&path
, buf
);
252 buf
->f_namelen
= ofs
->namelen
;
253 buf
->f_type
= OVERLAYFS_SUPER_MAGIC
;
262 * Prints the mount options for a given superblock.
263 * Returns zero; does not fail.
265 static int ovl_show_options(struct seq_file
*m
, struct dentry
*dentry
)
267 struct super_block
*sb
= dentry
->d_sb
;
268 struct ovl_fs
*ufs
= sb
->s_fs_info
;
270 seq_show_option(m
, "lowerdir", ufs
->config
.lowerdir
);
271 if (ufs
->config
.upperdir
) {
272 seq_show_option(m
, "upperdir", ufs
->config
.upperdir
);
273 seq_show_option(m
, "workdir", ufs
->config
.workdir
);
275 if (ufs
->config
.default_permissions
)
276 seq_puts(m
, ",default_permissions");
277 if (ufs
->config
.redirect_dir
!= ovl_redirect_dir_def
)
278 seq_printf(m
, ",redirect_dir=%s",
279 ufs
->config
.redirect_dir
? "on" : "off");
283 static int ovl_remount(struct super_block
*sb
, int *flags
, char *data
)
285 struct ovl_fs
*ufs
= sb
->s_fs_info
;
287 if (!(*flags
& MS_RDONLY
) && (!ufs
->upper_mnt
|| !ufs
->workdir
))
293 static const struct super_operations ovl_super_operations
= {
294 .alloc_inode
= ovl_alloc_inode
,
295 .destroy_inode
= ovl_destroy_inode
,
296 .drop_inode
= generic_delete_inode
,
297 .put_super
= ovl_put_super
,
298 .sync_fs
= ovl_sync_fs
,
299 .statfs
= ovl_statfs
,
300 .show_options
= ovl_show_options
,
301 .remount_fs
= ovl_remount
,
308 OPT_DEFAULT_PERMISSIONS
,
310 OPT_REDIRECT_DIR_OFF
,
314 static const match_table_t ovl_tokens
= {
315 {OPT_LOWERDIR
, "lowerdir=%s"},
316 {OPT_UPPERDIR
, "upperdir=%s"},
317 {OPT_WORKDIR
, "workdir=%s"},
318 {OPT_DEFAULT_PERMISSIONS
, "default_permissions"},
319 {OPT_REDIRECT_DIR_ON
, "redirect_dir=on"},
320 {OPT_REDIRECT_DIR_OFF
, "redirect_dir=off"},
324 static char *ovl_next_opt(char **s
)
332 for (p
= sbegin
; *p
; p
++) {
337 } else if (*p
== ',') {
347 static int ovl_parse_opt(char *opt
, struct ovl_config
*config
)
351 while ((p
= ovl_next_opt(&opt
)) != NULL
) {
353 substring_t args
[MAX_OPT_ARGS
];
358 token
= match_token(p
, ovl_tokens
, args
);
361 kfree(config
->upperdir
);
362 config
->upperdir
= match_strdup(&args
[0]);
363 if (!config
->upperdir
)
368 kfree(config
->lowerdir
);
369 config
->lowerdir
= match_strdup(&args
[0]);
370 if (!config
->lowerdir
)
375 kfree(config
->workdir
);
376 config
->workdir
= match_strdup(&args
[0]);
377 if (!config
->workdir
)
381 case OPT_DEFAULT_PERMISSIONS
:
382 config
->default_permissions
= true;
385 case OPT_REDIRECT_DIR_ON
:
386 config
->redirect_dir
= true;
389 case OPT_REDIRECT_DIR_OFF
:
390 config
->redirect_dir
= false;
394 pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p
);
399 /* Workdir is useless in non-upper mount */
400 if (!config
->upperdir
&& config
->workdir
) {
401 pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
403 kfree(config
->workdir
);
404 config
->workdir
= NULL
;
410 #define OVL_WORKDIR_NAME "work"
412 static struct dentry
*ovl_workdir_create(struct vfsmount
*mnt
,
413 struct dentry
*dentry
)
415 struct inode
*dir
= dentry
->d_inode
;
418 bool retried
= false;
420 err
= mnt_want_write(mnt
);
424 inode_lock_nested(dir
, I_MUTEX_PARENT
);
426 work
= lookup_one_len(OVL_WORKDIR_NAME
, dentry
,
427 strlen(OVL_WORKDIR_NAME
));
430 struct iattr attr
= {
431 .ia_valid
= ATTR_MODE
,
432 .ia_mode
= S_IFDIR
| 0,
441 ovl_workdir_cleanup(dir
, mnt
, work
, 0);
446 err
= ovl_create_real(dir
, work
,
447 &(struct cattr
){.mode
= S_IFDIR
| 0},
453 * Try to remove POSIX ACL xattrs from workdir. We are good if:
455 * a) success (there was a POSIX ACL xattr and was removed)
456 * b) -ENODATA (there was no POSIX ACL xattr)
457 * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported)
459 * There are various other error values that could effectively
460 * mean that the xattr doesn't exist (e.g. -ERANGE is returned
461 * if the xattr name is too long), but the set of filesystems
462 * allowed as upper are limited to "normal" ones, where checking
463 * for the above two errors is sufficient.
465 err
= vfs_removexattr(work
, XATTR_NAME_POSIX_ACL_DEFAULT
);
466 if (err
&& err
!= -ENODATA
&& err
!= -EOPNOTSUPP
)
469 err
= vfs_removexattr(work
, XATTR_NAME_POSIX_ACL_ACCESS
);
470 if (err
&& err
!= -ENODATA
&& err
!= -EOPNOTSUPP
)
473 /* Clear any inherited mode bits */
474 inode_lock(work
->d_inode
);
475 err
= notify_change(work
, &attr
, NULL
);
476 inode_unlock(work
->d_inode
);
492 static void ovl_unescape(char *s
)
505 static int ovl_mount_dir_noesc(const char *name
, struct path
*path
)
510 pr_err("overlayfs: empty lowerdir\n");
513 err
= kern_path(name
, LOOKUP_FOLLOW
, path
);
515 pr_err("overlayfs: failed to resolve '%s': %i\n", name
, err
);
519 if (ovl_dentry_weird(path
->dentry
)) {
520 pr_err("overlayfs: filesystem on '%s' not supported\n", name
);
523 if (!d_is_dir(path
->dentry
)) {
524 pr_err("overlayfs: '%s' not a directory\n", name
);
535 static int ovl_mount_dir(const char *name
, struct path
*path
)
538 char *tmp
= kstrdup(name
, GFP_KERNEL
);
542 err
= ovl_mount_dir_noesc(tmp
, path
);
545 if (ovl_dentry_remote(path
->dentry
)) {
546 pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n",
556 static int ovl_check_namelen(struct path
*path
, struct ovl_fs
*ofs
,
559 struct kstatfs statfs
;
560 int err
= vfs_statfs(path
, &statfs
);
563 pr_err("overlayfs: statfs failed on '%s'\n", name
);
565 ofs
->namelen
= max(ofs
->namelen
, statfs
.f_namelen
);
570 static int ovl_lower_dir(const char *name
, struct path
*path
,
571 struct ovl_fs
*ofs
, int *stack_depth
, bool *remote
)
575 err
= ovl_mount_dir_noesc(name
, path
);
579 err
= ovl_check_namelen(path
, ofs
, name
);
583 *stack_depth
= max(*stack_depth
, path
->mnt
->mnt_sb
->s_stack_depth
);
585 if (ovl_dentry_remote(path
->dentry
))
596 /* Workdir should not be subdir of upperdir and vice versa */
597 static bool ovl_workdir_ok(struct dentry
*workdir
, struct dentry
*upperdir
)
601 if (workdir
!= upperdir
) {
602 ok
= (lock_rename(workdir
, upperdir
) == NULL
);
603 unlock_rename(workdir
, upperdir
);
608 static unsigned int ovl_split_lowerdirs(char *str
)
610 unsigned int ctr
= 1;
613 for (s
= d
= str
;; s
++, d
++) {
616 } else if (*s
== ':') {
628 static int __maybe_unused
629 ovl_posix_acl_xattr_get(const struct xattr_handler
*handler
,
630 struct dentry
*dentry
, struct inode
*inode
,
631 const char *name
, void *buffer
, size_t size
)
633 return ovl_xattr_get(dentry
, handler
->name
, buffer
, size
);
636 static int __maybe_unused
637 ovl_posix_acl_xattr_set(const struct xattr_handler
*handler
,
638 struct dentry
*dentry
, struct inode
*inode
,
639 const char *name
, const void *value
,
640 size_t size
, int flags
)
642 struct dentry
*workdir
= ovl_workdir(dentry
);
643 struct inode
*realinode
= ovl_inode_real(inode
);
644 struct posix_acl
*acl
= NULL
;
647 /* Check that everything is OK before copy-up */
649 acl
= posix_acl_from_xattr(&init_user_ns
, value
, size
);
654 if (!IS_POSIXACL(d_inode(workdir
)))
655 goto out_acl_release
;
656 if (!realinode
->i_op
->set_acl
)
657 goto out_acl_release
;
658 if (handler
->flags
== ACL_TYPE_DEFAULT
&& !S_ISDIR(inode
->i_mode
)) {
659 err
= acl
? -EACCES
: 0;
660 goto out_acl_release
;
663 if (!inode_owner_or_capable(inode
))
664 goto out_acl_release
;
666 posix_acl_release(acl
);
669 * Check if sgid bit needs to be cleared (actual setacl operation will
670 * be done with mounter's capabilities and so that won't do it for us).
672 if (unlikely(inode
->i_mode
& S_ISGID
) &&
673 handler
->flags
== ACL_TYPE_ACCESS
&&
674 !in_group_p(inode
->i_gid
) &&
675 !capable_wrt_inode_uidgid(inode
, CAP_FSETID
)) {
676 struct iattr iattr
= { .ia_valid
= ATTR_KILL_SGID
};
678 err
= ovl_setattr(dentry
, &iattr
);
683 err
= ovl_xattr_set(dentry
, handler
->name
, value
, size
, flags
);
685 ovl_copyattr(ovl_inode_real(inode
), inode
);
690 posix_acl_release(acl
);
694 static int ovl_own_xattr_get(const struct xattr_handler
*handler
,
695 struct dentry
*dentry
, struct inode
*inode
,
696 const char *name
, void *buffer
, size_t size
)
701 static int ovl_own_xattr_set(const struct xattr_handler
*handler
,
702 struct dentry
*dentry
, struct inode
*inode
,
703 const char *name
, const void *value
,
704 size_t size
, int flags
)
709 static int ovl_other_xattr_get(const struct xattr_handler
*handler
,
710 struct dentry
*dentry
, struct inode
*inode
,
711 const char *name
, void *buffer
, size_t size
)
713 return ovl_xattr_get(dentry
, name
, buffer
, size
);
716 static int ovl_other_xattr_set(const struct xattr_handler
*handler
,
717 struct dentry
*dentry
, struct inode
*inode
,
718 const char *name
, const void *value
,
719 size_t size
, int flags
)
721 return ovl_xattr_set(dentry
, name
, value
, size
, flags
);
724 static const struct xattr_handler __maybe_unused
725 ovl_posix_acl_access_xattr_handler
= {
726 .name
= XATTR_NAME_POSIX_ACL_ACCESS
,
727 .flags
= ACL_TYPE_ACCESS
,
728 .get
= ovl_posix_acl_xattr_get
,
729 .set
= ovl_posix_acl_xattr_set
,
732 static const struct xattr_handler __maybe_unused
733 ovl_posix_acl_default_xattr_handler
= {
734 .name
= XATTR_NAME_POSIX_ACL_DEFAULT
,
735 .flags
= ACL_TYPE_DEFAULT
,
736 .get
= ovl_posix_acl_xattr_get
,
737 .set
= ovl_posix_acl_xattr_set
,
740 static const struct xattr_handler ovl_own_xattr_handler
= {
741 .prefix
= OVL_XATTR_PREFIX
,
742 .get
= ovl_own_xattr_get
,
743 .set
= ovl_own_xattr_set
,
746 static const struct xattr_handler ovl_other_xattr_handler
= {
747 .prefix
= "", /* catch all */
748 .get
= ovl_other_xattr_get
,
749 .set
= ovl_other_xattr_set
,
752 static const struct xattr_handler
*ovl_xattr_handlers
[] = {
753 #ifdef CONFIG_FS_POSIX_ACL
754 &ovl_posix_acl_access_xattr_handler
,
755 &ovl_posix_acl_default_xattr_handler
,
757 &ovl_own_xattr_handler
,
758 &ovl_other_xattr_handler
,
762 static int ovl_fill_super(struct super_block
*sb
, void *data
, int silent
)
764 struct path upperpath
= { };
765 struct path workpath
= { };
766 struct dentry
*root_dentry
;
767 struct ovl_entry
*oe
;
769 struct path
*stack
= NULL
;
772 unsigned int numlower
;
773 unsigned int stacklen
= 0;
780 ufs
= kzalloc(sizeof(struct ovl_fs
), GFP_KERNEL
);
784 init_waitqueue_head(&ufs
->copyup_wq
);
785 ufs
->config
.redirect_dir
= ovl_redirect_dir_def
;
786 err
= ovl_parse_opt((char *) data
, &ufs
->config
);
788 goto out_free_config
;
791 if (!ufs
->config
.lowerdir
) {
793 pr_err("overlayfs: missing 'lowerdir'\n");
794 goto out_free_config
;
797 sb
->s_stack_depth
= 0;
798 sb
->s_maxbytes
= MAX_LFS_FILESIZE
;
799 if (ufs
->config
.upperdir
) {
800 if (!ufs
->config
.workdir
) {
801 pr_err("overlayfs: missing 'workdir'\n");
802 goto out_free_config
;
805 err
= ovl_mount_dir(ufs
->config
.upperdir
, &upperpath
);
807 goto out_free_config
;
809 /* Upper fs should not be r/o */
810 if (upperpath
.mnt
->mnt_sb
->s_flags
& MS_RDONLY
) {
811 pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n");
813 goto out_put_upperpath
;
816 err
= ovl_check_namelen(&upperpath
, ufs
, ufs
->config
.upperdir
);
818 goto out_put_upperpath
;
820 err
= ovl_mount_dir(ufs
->config
.workdir
, &workpath
);
822 goto out_put_upperpath
;
825 if (upperpath
.mnt
!= workpath
.mnt
) {
826 pr_err("overlayfs: workdir and upperdir must reside under the same mount\n");
827 goto out_put_workpath
;
829 if (!ovl_workdir_ok(workpath
.dentry
, upperpath
.dentry
)) {
830 pr_err("overlayfs: workdir and upperdir must be separate subtrees\n");
831 goto out_put_workpath
;
833 sb
->s_stack_depth
= upperpath
.mnt
->mnt_sb
->s_stack_depth
;
836 lowertmp
= kstrdup(ufs
->config
.lowerdir
, GFP_KERNEL
);
838 goto out_put_workpath
;
841 stacklen
= ovl_split_lowerdirs(lowertmp
);
842 if (stacklen
> OVL_MAX_STACK
) {
843 pr_err("overlayfs: too many lower directories, limit is %d\n",
845 goto out_free_lowertmp
;
846 } else if (!ufs
->config
.upperdir
&& stacklen
== 1) {
847 pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
848 goto out_free_lowertmp
;
852 stack
= kcalloc(stacklen
, sizeof(struct path
), GFP_KERNEL
);
854 goto out_free_lowertmp
;
858 for (numlower
= 0; numlower
< stacklen
; numlower
++) {
859 err
= ovl_lower_dir(lower
, &stack
[numlower
], ufs
,
860 &sb
->s_stack_depth
, &remote
);
862 goto out_put_lowerpath
;
864 lower
= strchr(lower
, '\0') + 1;
869 if (sb
->s_stack_depth
> FILESYSTEM_MAX_STACK_DEPTH
) {
870 pr_err("overlayfs: maximum fs stacking depth exceeded\n");
871 goto out_put_lowerpath
;
874 if (ufs
->config
.upperdir
) {
875 ufs
->upper_mnt
= clone_private_mount(&upperpath
);
876 err
= PTR_ERR(ufs
->upper_mnt
);
877 if (IS_ERR(ufs
->upper_mnt
)) {
878 pr_err("overlayfs: failed to clone upperpath\n");
879 goto out_put_lowerpath
;
881 /* Don't inherit atime flags */
882 ufs
->upper_mnt
->mnt_flags
&= ~(MNT_NOATIME
| MNT_NODIRATIME
| MNT_RELATIME
);
884 sb
->s_time_gran
= ufs
->upper_mnt
->mnt_sb
->s_time_gran
;
886 ufs
->workdir
= ovl_workdir_create(ufs
->upper_mnt
, workpath
.dentry
);
887 err
= PTR_ERR(ufs
->workdir
);
888 if (IS_ERR(ufs
->workdir
)) {
889 pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n",
890 ufs
->config
.workdir
, OVL_WORKDIR_NAME
, -err
);
891 sb
->s_flags
|= MS_RDONLY
;
896 * Upper should support d_type, else whiteouts are visible.
897 * Given workdir and upper are on same fs, we can do
898 * iterate_dir() on workdir. This check requires successful
899 * creation of workdir in previous step.
904 err
= ovl_check_d_type_supported(&workpath
);
906 goto out_put_workdir
;
909 * We allowed this configuration and don't want to
910 * break users over kernel upgrade. So warn instead
914 pr_warn("overlayfs: upper fs needs to support d_type.\n");
916 /* Check if upper/work fs supports O_TMPFILE */
917 temp
= ovl_do_tmpfile(ufs
->workdir
, S_IFREG
| 0);
918 ufs
->tmpfile
= !IS_ERR(temp
);
922 pr_warn("overlayfs: upper fs does not support tmpfile.\n");
925 * Check if upper/work fs supports trusted.overlay.*
928 err
= ovl_do_setxattr(ufs
->workdir
, OVL_XATTR_OPAQUE
,
932 pr_warn("overlayfs: upper fs does not support xattr.\n");
934 vfs_removexattr(ufs
->workdir
, OVL_XATTR_OPAQUE
);
940 ufs
->lower_mnt
= kcalloc(numlower
, sizeof(struct vfsmount
*), GFP_KERNEL
);
941 if (ufs
->lower_mnt
== NULL
)
942 goto out_put_workdir
;
943 for (i
= 0; i
< numlower
; i
++) {
944 struct vfsmount
*mnt
= clone_private_mount(&stack
[i
]);
948 pr_err("overlayfs: failed to clone lowerpath\n");
949 goto out_put_lower_mnt
;
952 * Make lower_mnt R/O. That way fchmod/fchown on lower file
953 * will fail instead of modifying lower fs.
955 mnt
->mnt_flags
|= MNT_READONLY
| MNT_NOATIME
;
957 ufs
->lower_mnt
[ufs
->numlower
] = mnt
;
960 /* Check if all lower layers are on same sb */
962 ufs
->same_sb
= mnt
->mnt_sb
;
963 else if (ufs
->same_sb
!= mnt
->mnt_sb
)
967 /* If the upper fs is nonexistent, we mark overlayfs r/o too */
969 sb
->s_flags
|= MS_RDONLY
;
970 else if (ufs
->upper_mnt
->mnt_sb
!= ufs
->same_sb
)
974 sb
->s_d_op
= &ovl_reval_dentry_operations
;
976 sb
->s_d_op
= &ovl_dentry_operations
;
978 ufs
->creator_cred
= cred
= prepare_creds();
980 goto out_put_lower_mnt
;
982 /* Never override disk quota limits or use reserved space */
983 cap_lower(cred
->cap_effective
, CAP_SYS_RESOURCE
);
986 oe
= ovl_alloc_entry(numlower
);
990 sb
->s_magic
= OVERLAYFS_SUPER_MAGIC
;
991 sb
->s_op
= &ovl_super_operations
;
992 sb
->s_xattr
= ovl_xattr_handlers
;
994 sb
->s_flags
|= MS_POSIXACL
| MS_NOREMOTELOCK
;
996 root_dentry
= d_make_root(ovl_new_inode(sb
, S_IFDIR
, 0));
1000 mntput(upperpath
.mnt
);
1001 for (i
= 0; i
< numlower
; i
++)
1002 mntput(stack
[i
].mnt
);
1003 path_put(&workpath
);
1006 if (upperpath
.dentry
) {
1007 oe
->impure
= ovl_is_impuredir(upperpath
.dentry
);
1009 for (i
= 0; i
< numlower
; i
++) {
1010 oe
->lowerstack
[i
].dentry
= stack
[i
].dentry
;
1011 oe
->lowerstack
[i
].mnt
= ufs
->lower_mnt
[i
];
1015 root_dentry
->d_fsdata
= oe
;
1017 ovl_inode_init(d_inode(root_dentry
), upperpath
.dentry
,
1018 ovl_dentry_lower(root_dentry
));
1020 sb
->s_root
= root_dentry
;
1027 put_cred(ufs
->creator_cred
);
1029 for (i
= 0; i
< ufs
->numlower
; i
++)
1030 mntput(ufs
->lower_mnt
[i
]);
1031 kfree(ufs
->lower_mnt
);
1034 mntput(ufs
->upper_mnt
);
1036 for (i
= 0; i
< numlower
; i
++)
1037 path_put(&stack
[i
]);
1042 path_put(&workpath
);
1044 path_put(&upperpath
);
1046 kfree(ufs
->config
.lowerdir
);
1047 kfree(ufs
->config
.upperdir
);
1048 kfree(ufs
->config
.workdir
);
1054 static struct dentry
*ovl_mount(struct file_system_type
*fs_type
, int flags
,
1055 const char *dev_name
, void *raw_data
)
1057 return mount_nodev(fs_type
, flags
, raw_data
, ovl_fill_super
);
1060 static struct file_system_type ovl_fs_type
= {
1061 .owner
= THIS_MODULE
,
1064 .kill_sb
= kill_anon_super
,
1066 MODULE_ALIAS_FS("overlay");
1068 static void ovl_inode_init_once(void *foo
)
1070 struct ovl_inode
*oi
= foo
;
1072 inode_init_once(&oi
->vfs_inode
);
1075 static int __init
ovl_init(void)
1079 ovl_inode_cachep
= kmem_cache_create("ovl_inode",
1080 sizeof(struct ovl_inode
), 0,
1081 (SLAB_RECLAIM_ACCOUNT
|
1082 SLAB_MEM_SPREAD
|SLAB_ACCOUNT
),
1083 ovl_inode_init_once
);
1084 if (ovl_inode_cachep
== NULL
)
1087 err
= register_filesystem(&ovl_fs_type
);
1089 kmem_cache_destroy(ovl_inode_cachep
);
1094 static void __exit
ovl_exit(void)
1096 unregister_filesystem(&ovl_fs_type
);
1099 * Make sure all delayed rcu free inodes are flushed before we
1103 kmem_cache_destroy(ovl_inode_cachep
);
1107 module_init(ovl_init
);
1108 module_exit(ovl_exit
);