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 int ovl_check_append_only(struct inode *inode, int flag)
55 * This test was moot in vfs may_open() because overlay inode does
56 * not have the S_APPEND flag, so re-check on real upper inode
58 if (IS_APPEND(inode)) {
59 if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND))
68 static struct dentry *ovl_d_real(struct dentry *dentry,
69 const struct inode *inode,
70 unsigned int open_flags)
75 if (!d_is_reg(dentry)) {
76 if (!inode || inode == d_inode(dentry))
81 if (d_is_negative(dentry))
85 err = ovl_open_maybe_copy_up(dentry, open_flags);
90 real = ovl_dentry_upper(dentry);
91 if (real && (!inode || inode == d_inode(real))) {
93 err = ovl_check_append_only(d_inode(real), open_flags);
100 real = ovl_dentry_lower(dentry);
104 /* Handle recursion */
105 real = d_real(real, inode, open_flags);
107 if (!inode || inode == d_inode(real))
110 WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry,
111 inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0);
115 static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags)
117 struct ovl_entry *oe = dentry->d_fsdata;
121 for (i = 0; i < oe->numlower; i++) {
122 struct dentry *d = oe->lowerstack[i].dentry;
124 if (d->d_flags & DCACHE_OP_REVALIDATE) {
125 ret = d->d_op->d_revalidate(d, flags);
129 if (!(flags & LOOKUP_RCU))
138 static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags)
140 struct ovl_entry *oe = dentry->d_fsdata;
144 for (i = 0; i < oe->numlower; i++) {
145 struct dentry *d = oe->lowerstack[i].dentry;
147 if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) {
148 ret = d->d_op->d_weak_revalidate(d, flags);
156 static const struct dentry_operations ovl_dentry_operations = {
157 .d_release = ovl_dentry_release,
158 .d_real = ovl_d_real,
161 static const struct dentry_operations ovl_reval_dentry_operations = {
162 .d_release = ovl_dentry_release,
163 .d_real = ovl_d_real,
164 .d_revalidate = ovl_dentry_revalidate,
165 .d_weak_revalidate = ovl_dentry_weak_revalidate,
168 static void ovl_put_super(struct super_block *sb)
170 struct ovl_fs *ufs = sb->s_fs_info;
174 mntput(ufs->upper_mnt);
175 for (i = 0; i < ufs->numlower; i++)
176 mntput(ufs->lower_mnt[i]);
177 kfree(ufs->lower_mnt);
179 kfree(ufs->config.lowerdir);
180 kfree(ufs->config.upperdir);
181 kfree(ufs->config.workdir);
182 put_cred(ufs->creator_cred);
186 static int ovl_sync_fs(struct super_block *sb, int wait)
188 struct ovl_fs *ufs = sb->s_fs_info;
189 struct super_block *upper_sb;
194 upper_sb = ufs->upper_mnt->mnt_sb;
195 if (!upper_sb->s_op->sync_fs)
198 /* real inodes have already been synced by sync_filesystem(ovl_sb) */
199 down_read(&upper_sb->s_umount);
200 ret = upper_sb->s_op->sync_fs(upper_sb, wait);
201 up_read(&upper_sb->s_umount);
207 * @sb: The overlayfs super block
208 * @buf: The struct kstatfs to fill in with stats
210 * Get the filesystem statistics. As writes always target the upper layer
211 * filesystem pass the statfs to the upper filesystem (if it exists)
213 static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
215 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
216 struct dentry *root_dentry = dentry->d_sb->s_root;
220 ovl_path_real(root_dentry, &path);
222 err = vfs_statfs(&path, buf);
224 buf->f_namelen = ofs->namelen;
225 buf->f_type = OVERLAYFS_SUPER_MAGIC;
234 * Prints the mount options for a given superblock.
235 * Returns zero; does not fail.
237 static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
239 struct super_block *sb = dentry->d_sb;
240 struct ovl_fs *ufs = sb->s_fs_info;
242 seq_show_option(m, "lowerdir", ufs->config.lowerdir);
243 if (ufs->config.upperdir) {
244 seq_show_option(m, "upperdir", ufs->config.upperdir);
245 seq_show_option(m, "workdir", ufs->config.workdir);
247 if (ufs->config.default_permissions)
248 seq_puts(m, ",default_permissions");
249 if (ufs->config.redirect_dir != ovl_redirect_dir_def)
250 seq_printf(m, ",redirect_dir=%s",
251 ufs->config.redirect_dir ? "on" : "off");
255 static int ovl_remount(struct super_block *sb, int *flags, char *data)
257 struct ovl_fs *ufs = sb->s_fs_info;
259 if (!(*flags & MS_RDONLY) && (!ufs->upper_mnt || !ufs->workdir))
265 static const struct super_operations ovl_super_operations = {
266 .put_super = ovl_put_super,
267 .sync_fs = ovl_sync_fs,
268 .statfs = ovl_statfs,
269 .show_options = ovl_show_options,
270 .remount_fs = ovl_remount,
271 .drop_inode = generic_delete_inode,
278 OPT_DEFAULT_PERMISSIONS,
280 OPT_REDIRECT_DIR_OFF,
284 static const match_table_t ovl_tokens = {
285 {OPT_LOWERDIR, "lowerdir=%s"},
286 {OPT_UPPERDIR, "upperdir=%s"},
287 {OPT_WORKDIR, "workdir=%s"},
288 {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
289 {OPT_REDIRECT_DIR_ON, "redirect_dir=on"},
290 {OPT_REDIRECT_DIR_OFF, "redirect_dir=off"},
294 static char *ovl_next_opt(char **s)
302 for (p = sbegin; *p; p++) {
307 } else if (*p == ',') {
317 static int ovl_parse_opt(char *opt, struct ovl_config *config)
321 while ((p = ovl_next_opt(&opt)) != NULL) {
323 substring_t args[MAX_OPT_ARGS];
328 token = match_token(p, ovl_tokens, args);
331 kfree(config->upperdir);
332 config->upperdir = match_strdup(&args[0]);
333 if (!config->upperdir)
338 kfree(config->lowerdir);
339 config->lowerdir = match_strdup(&args[0]);
340 if (!config->lowerdir)
345 kfree(config->workdir);
346 config->workdir = match_strdup(&args[0]);
347 if (!config->workdir)
351 case OPT_DEFAULT_PERMISSIONS:
352 config->default_permissions = true;
355 case OPT_REDIRECT_DIR_ON:
356 config->redirect_dir = true;
359 case OPT_REDIRECT_DIR_OFF:
360 config->redirect_dir = false;
364 pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p);
369 /* Workdir is useless in non-upper mount */
370 if (!config->upperdir && config->workdir) {
371 pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
373 kfree(config->workdir);
374 config->workdir = NULL;
380 #define OVL_WORKDIR_NAME "work"
382 static struct dentry *ovl_workdir_create(struct vfsmount *mnt,
383 struct dentry *dentry)
385 struct inode *dir = dentry->d_inode;
388 bool retried = false;
390 err = mnt_want_write(mnt);
394 inode_lock_nested(dir, I_MUTEX_PARENT);
396 work = lookup_one_len(OVL_WORKDIR_NAME, dentry,
397 strlen(OVL_WORKDIR_NAME));
400 struct iattr attr = {
401 .ia_valid = ATTR_MODE,
402 .ia_mode = S_IFDIR | 0,
411 ovl_workdir_cleanup(dir, mnt, work, 0);
416 err = ovl_create_real(dir, work,
417 &(struct cattr){.mode = S_IFDIR | 0},
423 * Try to remove POSIX ACL xattrs from workdir. We are good if:
425 * a) success (there was a POSIX ACL xattr and was removed)
426 * b) -ENODATA (there was no POSIX ACL xattr)
427 * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported)
429 * There are various other error values that could effectively
430 * mean that the xattr doesn't exist (e.g. -ERANGE is returned
431 * if the xattr name is too long), but the set of filesystems
432 * allowed as upper are limited to "normal" ones, where checking
433 * for the above two errors is sufficient.
435 err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_DEFAULT);
436 if (err && err != -ENODATA && err != -EOPNOTSUPP)
439 err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_ACCESS);
440 if (err && err != -ENODATA && err != -EOPNOTSUPP)
443 /* Clear any inherited mode bits */
444 inode_lock(work->d_inode);
445 err = notify_change(work, &attr, NULL);
446 inode_unlock(work->d_inode);
462 static void ovl_unescape(char *s)
475 static int ovl_mount_dir_noesc(const char *name, struct path *path)
480 pr_err("overlayfs: empty lowerdir\n");
483 err = kern_path(name, LOOKUP_FOLLOW, path);
485 pr_err("overlayfs: failed to resolve '%s': %i\n", name, err);
489 if (ovl_dentry_weird(path->dentry)) {
490 pr_err("overlayfs: filesystem on '%s' not supported\n", name);
493 if (!d_is_dir(path->dentry)) {
494 pr_err("overlayfs: '%s' not a directory\n", name);
505 static int ovl_mount_dir(const char *name, struct path *path)
508 char *tmp = kstrdup(name, GFP_KERNEL);
512 err = ovl_mount_dir_noesc(tmp, path);
515 if (ovl_dentry_remote(path->dentry)) {
516 pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n",
526 static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs,
529 struct kstatfs statfs;
530 int err = vfs_statfs(path, &statfs);
533 pr_err("overlayfs: statfs failed on '%s'\n", name);
535 ofs->namelen = max(ofs->namelen, statfs.f_namelen);
540 static int ovl_lower_dir(const char *name, struct path *path,
541 struct ovl_fs *ofs, int *stack_depth, bool *remote)
545 err = ovl_mount_dir_noesc(name, path);
549 err = ovl_check_namelen(path, ofs, name);
553 *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth);
555 if (ovl_dentry_remote(path->dentry))
566 /* Workdir should not be subdir of upperdir and vice versa */
567 static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir)
571 if (workdir != upperdir) {
572 ok = (lock_rename(workdir, upperdir) == NULL);
573 unlock_rename(workdir, upperdir);
578 static unsigned int ovl_split_lowerdirs(char *str)
580 unsigned int ctr = 1;
583 for (s = d = str;; s++, d++) {
586 } else if (*s == ':') {
598 static int __maybe_unused
599 ovl_posix_acl_xattr_get(const struct xattr_handler *handler,
600 struct dentry *dentry, struct inode *inode,
601 const char *name, void *buffer, size_t size)
603 return ovl_xattr_get(dentry, handler->name, buffer, size);
606 static int __maybe_unused
607 ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
608 struct dentry *dentry, struct inode *inode,
609 const char *name, const void *value,
610 size_t size, int flags)
612 struct dentry *workdir = ovl_workdir(dentry);
613 struct inode *realinode = ovl_inode_real(inode, NULL);
614 struct posix_acl *acl = NULL;
617 /* Check that everything is OK before copy-up */
619 acl = posix_acl_from_xattr(&init_user_ns, value, size);
624 if (!IS_POSIXACL(d_inode(workdir)))
625 goto out_acl_release;
626 if (!realinode->i_op->set_acl)
627 goto out_acl_release;
628 if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) {
629 err = acl ? -EACCES : 0;
630 goto out_acl_release;
633 if (!inode_owner_or_capable(inode))
634 goto out_acl_release;
636 posix_acl_release(acl);
639 * Check if sgid bit needs to be cleared (actual setacl operation will
640 * be done with mounter's capabilities and so that won't do it for us).
642 if (unlikely(inode->i_mode & S_ISGID) &&
643 handler->flags == ACL_TYPE_ACCESS &&
644 !in_group_p(inode->i_gid) &&
645 !capable_wrt_inode_uidgid(inode, CAP_FSETID)) {
646 struct iattr iattr = { .ia_valid = ATTR_KILL_SGID };
648 err = ovl_setattr(dentry, &iattr);
653 err = ovl_xattr_set(dentry, handler->name, value, size, flags);
655 ovl_copyattr(ovl_inode_real(inode, NULL), inode);
660 posix_acl_release(acl);
664 static int ovl_own_xattr_get(const struct xattr_handler *handler,
665 struct dentry *dentry, struct inode *inode,
666 const char *name, void *buffer, size_t size)
671 static int ovl_own_xattr_set(const struct xattr_handler *handler,
672 struct dentry *dentry, struct inode *inode,
673 const char *name, const void *value,
674 size_t size, int flags)
679 static int ovl_other_xattr_get(const struct xattr_handler *handler,
680 struct dentry *dentry, struct inode *inode,
681 const char *name, void *buffer, size_t size)
683 return ovl_xattr_get(dentry, name, buffer, size);
686 static int ovl_other_xattr_set(const struct xattr_handler *handler,
687 struct dentry *dentry, struct inode *inode,
688 const char *name, const void *value,
689 size_t size, int flags)
691 return ovl_xattr_set(dentry, name, value, size, flags);
694 static const struct xattr_handler __maybe_unused
695 ovl_posix_acl_access_xattr_handler = {
696 .name = XATTR_NAME_POSIX_ACL_ACCESS,
697 .flags = ACL_TYPE_ACCESS,
698 .get = ovl_posix_acl_xattr_get,
699 .set = ovl_posix_acl_xattr_set,
702 static const struct xattr_handler __maybe_unused
703 ovl_posix_acl_default_xattr_handler = {
704 .name = XATTR_NAME_POSIX_ACL_DEFAULT,
705 .flags = ACL_TYPE_DEFAULT,
706 .get = ovl_posix_acl_xattr_get,
707 .set = ovl_posix_acl_xattr_set,
710 static const struct xattr_handler ovl_own_xattr_handler = {
711 .prefix = OVL_XATTR_PREFIX,
712 .get = ovl_own_xattr_get,
713 .set = ovl_own_xattr_set,
716 static const struct xattr_handler ovl_other_xattr_handler = {
717 .prefix = "", /* catch all */
718 .get = ovl_other_xattr_get,
719 .set = ovl_other_xattr_set,
722 static const struct xattr_handler *ovl_xattr_handlers[] = {
723 #ifdef CONFIG_FS_POSIX_ACL
724 &ovl_posix_acl_access_xattr_handler,
725 &ovl_posix_acl_default_xattr_handler,
727 &ovl_own_xattr_handler,
728 &ovl_other_xattr_handler,
732 static int ovl_fill_super(struct super_block *sb, void *data, int silent)
734 struct path upperpath = { };
735 struct path workpath = { };
736 struct dentry *root_dentry;
737 struct inode *realinode;
738 struct ovl_entry *oe;
740 struct path *stack = NULL;
743 unsigned int numlower;
744 unsigned int stacklen = 0;
751 ufs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL);
755 init_waitqueue_head(&ufs->copyup_wq);
756 ufs->config.redirect_dir = ovl_redirect_dir_def;
757 err = ovl_parse_opt((char *) data, &ufs->config);
759 goto out_free_config;
762 if (!ufs->config.lowerdir) {
764 pr_err("overlayfs: missing 'lowerdir'\n");
765 goto out_free_config;
768 sb->s_stack_depth = 0;
769 sb->s_maxbytes = MAX_LFS_FILESIZE;
770 if (ufs->config.upperdir) {
771 if (!ufs->config.workdir) {
772 pr_err("overlayfs: missing 'workdir'\n");
773 goto out_free_config;
776 err = ovl_mount_dir(ufs->config.upperdir, &upperpath);
778 goto out_free_config;
780 /* Upper fs should not be r/o */
781 if (upperpath.mnt->mnt_sb->s_flags & MS_RDONLY) {
782 pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n");
784 goto out_put_upperpath;
787 err = ovl_check_namelen(&upperpath, ufs, ufs->config.upperdir);
789 goto out_put_upperpath;
791 err = ovl_mount_dir(ufs->config.workdir, &workpath);
793 goto out_put_upperpath;
796 if (upperpath.mnt != workpath.mnt) {
797 pr_err("overlayfs: workdir and upperdir must reside under the same mount\n");
798 goto out_put_workpath;
800 if (!ovl_workdir_ok(workpath.dentry, upperpath.dentry)) {
801 pr_err("overlayfs: workdir and upperdir must be separate subtrees\n");
802 goto out_put_workpath;
804 sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth;
807 lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL);
809 goto out_put_workpath;
812 stacklen = ovl_split_lowerdirs(lowertmp);
813 if (stacklen > OVL_MAX_STACK) {
814 pr_err("overlayfs: too many lower directories, limit is %d\n",
816 goto out_free_lowertmp;
817 } else if (!ufs->config.upperdir && stacklen == 1) {
818 pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
819 goto out_free_lowertmp;
823 stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
825 goto out_free_lowertmp;
829 for (numlower = 0; numlower < stacklen; numlower++) {
830 err = ovl_lower_dir(lower, &stack[numlower], ufs,
831 &sb->s_stack_depth, &remote);
833 goto out_put_lowerpath;
835 lower = strchr(lower, '\0') + 1;
840 if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
841 pr_err("overlayfs: maximum fs stacking depth exceeded\n");
842 goto out_put_lowerpath;
845 if (ufs->config.upperdir) {
846 ufs->upper_mnt = clone_private_mount(&upperpath);
847 err = PTR_ERR(ufs->upper_mnt);
848 if (IS_ERR(ufs->upper_mnt)) {
849 pr_err("overlayfs: failed to clone upperpath\n");
850 goto out_put_lowerpath;
852 /* Don't inherit atime flags */
853 ufs->upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME);
855 sb->s_time_gran = ufs->upper_mnt->mnt_sb->s_time_gran;
857 ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry);
858 err = PTR_ERR(ufs->workdir);
859 if (IS_ERR(ufs->workdir)) {
860 pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n",
861 ufs->config.workdir, OVL_WORKDIR_NAME, -err);
862 sb->s_flags |= MS_RDONLY;
867 * Upper should support d_type, else whiteouts are visible.
868 * Given workdir and upper are on same fs, we can do
869 * iterate_dir() on workdir. This check requires successful
870 * creation of workdir in previous step.
875 err = ovl_check_d_type_supported(&workpath);
877 goto out_put_workdir;
880 * We allowed this configuration and don't want to
881 * break users over kernel upgrade. So warn instead
885 pr_warn("overlayfs: upper fs needs to support d_type.\n");
887 /* Check if upper/work fs supports O_TMPFILE */
888 temp = ovl_do_tmpfile(ufs->workdir, S_IFREG | 0);
889 ufs->tmpfile = !IS_ERR(temp);
893 pr_warn("overlayfs: upper fs does not support tmpfile.\n");
898 ufs->lower_mnt = kcalloc(numlower, sizeof(struct vfsmount *), GFP_KERNEL);
899 if (ufs->lower_mnt == NULL)
900 goto out_put_workdir;
901 for (i = 0; i < numlower; i++) {
902 struct vfsmount *mnt = clone_private_mount(&stack[i]);
906 pr_err("overlayfs: failed to clone lowerpath\n");
907 goto out_put_lower_mnt;
910 * Make lower_mnt R/O. That way fchmod/fchown on lower file
911 * will fail instead of modifying lower fs.
913 mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME;
915 ufs->lower_mnt[ufs->numlower] = mnt;
918 /* Check if all lower layers are on same sb */
920 ufs->same_sb = mnt->mnt_sb;
921 else if (ufs->same_sb != mnt->mnt_sb)
925 /* If the upper fs is nonexistent, we mark overlayfs r/o too */
927 sb->s_flags |= MS_RDONLY;
928 else if (ufs->upper_mnt->mnt_sb != ufs->same_sb)
932 sb->s_d_op = &ovl_reval_dentry_operations;
934 sb->s_d_op = &ovl_dentry_operations;
936 ufs->creator_cred = cred = prepare_creds();
938 goto out_put_lower_mnt;
940 /* Never override disk quota limits or use reserved space */
941 cap_lower(cred->cap_effective, CAP_SYS_RESOURCE);
944 oe = ovl_alloc_entry(numlower);
948 sb->s_magic = OVERLAYFS_SUPER_MAGIC;
949 sb->s_op = &ovl_super_operations;
950 sb->s_xattr = ovl_xattr_handlers;
952 sb->s_flags |= MS_POSIXACL | MS_NOREMOTELOCK;
954 root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0));
958 mntput(upperpath.mnt);
959 for (i = 0; i < numlower; i++)
960 mntput(stack[i].mnt);
964 oe->__upperdentry = upperpath.dentry;
965 for (i = 0; i < numlower; i++) {
966 oe->lowerstack[i].dentry = stack[i].dentry;
967 oe->lowerstack[i].mnt = ufs->lower_mnt[i];
971 root_dentry->d_fsdata = oe;
973 realinode = d_inode(ovl_dentry_real(root_dentry));
974 ovl_inode_init(d_inode(root_dentry), realinode, !!upperpath.dentry);
975 ovl_copyattr(realinode, d_inode(root_dentry));
977 sb->s_root = root_dentry;
984 put_cred(ufs->creator_cred);
986 for (i = 0; i < ufs->numlower; i++)
987 mntput(ufs->lower_mnt[i]);
988 kfree(ufs->lower_mnt);
991 mntput(ufs->upper_mnt);
993 for (i = 0; i < numlower; i++)
1001 path_put(&upperpath);
1003 kfree(ufs->config.lowerdir);
1004 kfree(ufs->config.upperdir);
1005 kfree(ufs->config.workdir);
1011 static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags,
1012 const char *dev_name, void *raw_data)
1014 return mount_nodev(fs_type, flags, raw_data, ovl_fill_super);
1017 static struct file_system_type ovl_fs_type = {
1018 .owner = THIS_MODULE,
1021 .kill_sb = kill_anon_super,
1023 MODULE_ALIAS_FS("overlay");
1025 static int __init ovl_init(void)
1027 return register_filesystem(&ovl_fs_type);
1030 static void __exit ovl_exit(void)
1032 unregister_filesystem(&ovl_fs_type);
1035 module_init(ovl_init);
1036 module_exit(ovl_exit);