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02b69b284c
If a directory has the "trusted.overlay.redirect" xattr, it means that the value of the xattr should be used to find the underlying directory on the next lower layer. The redirect may be relative or absolute. Absolute redirects begin with a slash. A relative redirect means: instead of the current dentry's name use the value of the redirect to find the directory in the next lower layer. Relative redirects must not contain a slash. An absolute redirect means: look up the directory relative to the root of the overlay using the value of the redirect in the next lower layer. Redirects work on lower layers as well. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
222 lines
7.4 KiB
C
222 lines
7.4 KiB
C
/*
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*
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* Copyright (C) 2011 Novell Inc.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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enum ovl_path_type {
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__OVL_PATH_UPPER = (1 << 0),
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__OVL_PATH_MERGE = (1 << 1),
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};
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#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
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#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
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#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
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#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
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#define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect"
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#define OVL_ISUPPER_MASK 1UL
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static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
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{
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int err = vfs_rmdir(dir, dentry);
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pr_debug("rmdir(%pd2) = %i\n", dentry, err);
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return err;
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}
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static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
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{
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int err = vfs_unlink(dir, dentry, NULL);
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pr_debug("unlink(%pd2) = %i\n", dentry, err);
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return err;
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}
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static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
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struct dentry *new_dentry, bool debug)
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{
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int err = vfs_link(old_dentry, dir, new_dentry, NULL);
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if (debug) {
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pr_debug("link(%pd2, %pd2) = %i\n",
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old_dentry, new_dentry, err);
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}
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return err;
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}
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static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
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umode_t mode, bool debug)
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{
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int err = vfs_create(dir, dentry, mode, true);
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if (debug)
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pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
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return err;
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}
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static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
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umode_t mode, bool debug)
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{
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int err = vfs_mkdir(dir, dentry, mode);
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if (debug)
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pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
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return err;
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}
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static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
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umode_t mode, dev_t dev, bool debug)
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{
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int err = vfs_mknod(dir, dentry, mode, dev);
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if (debug) {
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pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n",
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dentry, mode, dev, err);
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}
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return err;
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}
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static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
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const char *oldname, bool debug)
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{
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int err = vfs_symlink(dir, dentry, oldname);
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if (debug)
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pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
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return err;
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}
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static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
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const void *value, size_t size, int flags)
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{
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int err = vfs_setxattr(dentry, name, value, size, flags);
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pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
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dentry, name, (int) size, (char *) value, flags, err);
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return err;
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}
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static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
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{
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int err = vfs_removexattr(dentry, name);
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pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
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return err;
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}
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static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
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struct inode *newdir, struct dentry *newdentry,
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unsigned int flags)
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{
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int err;
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pr_debug("rename(%pd2, %pd2, 0x%x)\n",
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olddentry, newdentry, flags);
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err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
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if (err) {
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pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
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olddentry, newdentry, err);
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}
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return err;
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}
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static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
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{
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int err = vfs_whiteout(dir, dentry);
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pr_debug("whiteout(%pd2) = %i\n", dentry, err);
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return err;
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}
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static inline struct inode *ovl_inode_real(struct inode *inode, bool *is_upper)
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{
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unsigned long x = (unsigned long) READ_ONCE(inode->i_private);
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if (is_upper)
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*is_upper = x & OVL_ISUPPER_MASK;
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return (struct inode *) (x & ~OVL_ISUPPER_MASK);
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}
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/* util.c */
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int ovl_want_write(struct dentry *dentry);
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void ovl_drop_write(struct dentry *dentry);
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struct dentry *ovl_workdir(struct dentry *dentry);
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const struct cred *ovl_override_creds(struct super_block *sb);
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struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
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bool ovl_dentry_remote(struct dentry *dentry);
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bool ovl_dentry_weird(struct dentry *dentry);
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enum ovl_path_type ovl_path_type(struct dentry *dentry);
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void ovl_path_upper(struct dentry *dentry, struct path *path);
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void ovl_path_lower(struct dentry *dentry, struct path *path);
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enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
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struct dentry *ovl_dentry_upper(struct dentry *dentry);
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struct dentry *ovl_dentry_lower(struct dentry *dentry);
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struct dentry *ovl_dentry_real(struct dentry *dentry);
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struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
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void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
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bool ovl_dentry_is_opaque(struct dentry *dentry);
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bool ovl_dentry_is_whiteout(struct dentry *dentry);
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void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque);
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void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
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void ovl_inode_init(struct inode *inode, struct inode *realinode,
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bool is_upper);
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void ovl_inode_update(struct inode *inode, struct inode *upperinode);
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void ovl_dentry_version_inc(struct dentry *dentry);
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u64 ovl_dentry_version_get(struct dentry *dentry);
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bool ovl_is_whiteout(struct dentry *dentry);
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struct file *ovl_path_open(struct path *path, int flags);
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/* namei.c */
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int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
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struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
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bool ovl_lower_positive(struct dentry *dentry);
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/* readdir.c */
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extern const struct file_operations ovl_dir_operations;
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int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
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void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
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void ovl_cache_free(struct list_head *list);
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int ovl_check_d_type_supported(struct path *realpath);
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void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
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struct dentry *dentry, int level);
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/* inode.c */
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int ovl_setattr(struct dentry *dentry, struct iattr *attr);
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int ovl_permission(struct inode *inode, int mask);
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int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
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size_t size, int flags);
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int ovl_xattr_get(struct dentry *dentry, const char *name,
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void *value, size_t size);
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ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
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struct posix_acl *ovl_get_acl(struct inode *inode, int type);
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int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
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int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
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bool ovl_is_private_xattr(const char *name);
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struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
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struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode);
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static inline void ovl_copyattr(struct inode *from, struct inode *to)
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{
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to->i_uid = from->i_uid;
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to->i_gid = from->i_gid;
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to->i_mode = from->i_mode;
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to->i_atime = from->i_atime;
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to->i_mtime = from->i_mtime;
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to->i_ctime = from->i_ctime;
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}
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/* dir.c */
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extern const struct inode_operations ovl_dir_inode_operations;
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struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry);
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int ovl_create_real(struct inode *dir, struct dentry *newdentry,
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struct kstat *stat, const char *link,
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struct dentry *hardlink, bool debug);
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void ovl_cleanup(struct inode *dir, struct dentry *dentry);
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/* copy_up.c */
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int ovl_copy_up(struct dentry *dentry);
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int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
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struct path *lowerpath, struct kstat *stat);
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int ovl_copy_xattr(struct dentry *old, struct dentry *new);
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int ovl_set_attr(struct dentry *upper, struct kstat *stat);
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