2 * Copyright (C) 2011 Novell Inc.
3 * Copyright (C) 2016 Red Hat, 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/mount.h>
12 #include <linux/slab.h>
13 #include <linux/cred.h>
14 #include <linux/xattr.h>
15 #include "overlayfs.h"
16 #include "ovl_entry.h"
18 int ovl_want_write(struct dentry *dentry)
20 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
21 return mnt_want_write(ofs->upper_mnt);
24 void ovl_drop_write(struct dentry *dentry)
26 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
27 mnt_drop_write(ofs->upper_mnt);
30 struct dentry *ovl_workdir(struct dentry *dentry)
32 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
36 const struct cred *ovl_override_creds(struct super_block *sb)
38 struct ovl_fs *ofs = sb->s_fs_info;
40 return override_creds(ofs->creator_cred);
43 struct super_block *ovl_same_sb(struct super_block *sb)
45 struct ovl_fs *ofs = sb->s_fs_info;
50 struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
52 size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
53 struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
56 oe->numlower = numlower;
61 bool ovl_dentry_remote(struct dentry *dentry)
63 return dentry->d_flags &
64 (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
68 bool ovl_dentry_weird(struct dentry *dentry)
70 return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
71 DCACHE_MANAGE_TRANSIT |
76 enum ovl_path_type ovl_path_type(struct dentry *dentry)
78 struct ovl_entry *oe = dentry->d_fsdata;
79 enum ovl_path_type type = 0;
81 if (oe->__upperdentry) {
82 type = __OVL_PATH_UPPER;
85 * Non-dir dentry can hold lower dentry of its copy up origin.
88 type |= __OVL_PATH_ORIGIN;
90 type |= __OVL_PATH_MERGE;
94 type |= __OVL_PATH_MERGE;
99 void ovl_path_upper(struct dentry *dentry, struct path *path)
101 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
102 struct ovl_entry *oe = dentry->d_fsdata;
104 path->mnt = ofs->upper_mnt;
105 path->dentry = ovl_upperdentry_dereference(oe);
108 void ovl_path_lower(struct dentry *dentry, struct path *path)
110 struct ovl_entry *oe = dentry->d_fsdata;
112 *path = oe->numlower ? oe->lowerstack[0] : (struct path) { };
115 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
117 enum ovl_path_type type = ovl_path_type(dentry);
119 if (!OVL_TYPE_UPPER(type))
120 ovl_path_lower(dentry, path);
122 ovl_path_upper(dentry, path);
127 struct dentry *ovl_dentry_upper(struct dentry *dentry)
129 struct ovl_entry *oe = dentry->d_fsdata;
131 return ovl_upperdentry_dereference(oe);
134 static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
136 return oe->numlower ? oe->lowerstack[0].dentry : NULL;
139 struct dentry *ovl_dentry_lower(struct dentry *dentry)
141 struct ovl_entry *oe = dentry->d_fsdata;
143 return __ovl_dentry_lower(oe);
146 struct dentry *ovl_dentry_real(struct dentry *dentry)
148 struct ovl_entry *oe = dentry->d_fsdata;
149 struct dentry *realdentry;
151 realdentry = ovl_upperdentry_dereference(oe);
153 realdentry = __ovl_dentry_lower(oe);
158 struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
160 struct ovl_entry *oe = dentry->d_fsdata;
165 void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
167 struct ovl_entry *oe = dentry->d_fsdata;
172 bool ovl_dentry_is_opaque(struct dentry *dentry)
174 struct ovl_entry *oe = dentry->d_fsdata;
178 bool ovl_dentry_is_whiteout(struct dentry *dentry)
180 return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
183 void ovl_dentry_set_opaque(struct dentry *dentry)
185 struct ovl_entry *oe = dentry->d_fsdata;
190 bool ovl_redirect_dir(struct super_block *sb)
192 struct ovl_fs *ofs = sb->s_fs_info;
194 return ofs->config.redirect_dir && !ofs->noxattr;
197 const char *ovl_dentry_get_redirect(struct dentry *dentry)
199 struct ovl_entry *oe = dentry->d_fsdata;
204 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
206 struct ovl_entry *oe = dentry->d_fsdata;
209 oe->redirect = redirect;
212 void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
214 struct ovl_entry *oe = dentry->d_fsdata;
216 WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
217 WARN_ON(oe->__upperdentry);
219 * Make sure upperdentry is consistent before making it visible to
220 * ovl_upperdentry_dereference().
223 oe->__upperdentry = upperdentry;
226 void ovl_inode_init(struct inode *inode, struct inode *realinode, bool is_upper)
228 WRITE_ONCE(inode->i_private, (unsigned long) realinode |
229 (is_upper ? OVL_ISUPPER_MASK : 0));
232 void ovl_inode_update(struct inode *inode, struct inode *upperinode)
234 WARN_ON(!upperinode);
235 WARN_ON(!inode_unhashed(inode));
236 WRITE_ONCE(inode->i_private,
237 (unsigned long) upperinode | OVL_ISUPPER_MASK);
238 if (!S_ISDIR(upperinode->i_mode))
239 __insert_inode_hash(inode, (unsigned long) upperinode);
242 void ovl_dentry_version_inc(struct dentry *dentry)
244 struct ovl_entry *oe = dentry->d_fsdata;
246 WARN_ON(!inode_is_locked(dentry->d_inode));
250 u64 ovl_dentry_version_get(struct dentry *dentry)
252 struct ovl_entry *oe = dentry->d_fsdata;
254 WARN_ON(!inode_is_locked(dentry->d_inode));
258 bool ovl_is_whiteout(struct dentry *dentry)
260 struct inode *inode = dentry->d_inode;
262 return inode && IS_WHITEOUT(inode);
265 struct file *ovl_path_open(struct path *path, int flags)
267 return dentry_open(path, flags | O_NOATIME, current_cred());
270 int ovl_copy_up_start(struct dentry *dentry)
272 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
273 struct ovl_entry *oe = dentry->d_fsdata;
276 spin_lock(&ofs->copyup_wq.lock);
277 err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying);
279 if (oe->__upperdentry)
280 err = 1; /* Already copied up */
284 spin_unlock(&ofs->copyup_wq.lock);
289 void ovl_copy_up_end(struct dentry *dentry)
291 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
292 struct ovl_entry *oe = dentry->d_fsdata;
294 spin_lock(&ofs->copyup_wq.lock);
296 wake_up_locked(&ofs->copyup_wq);
297 spin_unlock(&ofs->copyup_wq.lock);
300 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
301 const char *name, const void *value, size_t size,
305 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
310 err = ovl_do_setxattr(upperdentry, name, value, size, 0);
312 if (err == -EOPNOTSUPP) {
313 pr_warn("overlayfs: cannot set %s xattr on upper\n", name);