Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
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linux
1/*
2 * Copyright (C) 2011 Novell Inc.
3 * Copyright (C) 2016 Red Hat, Inc.
4 *
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.
8 */
9
10#include <linux/fs.h>
11#include <linux/mount.h>
12#include <linux/slab.h>
13#include <linux/xattr.h>
14#include "overlayfs.h"
15#include "ovl_entry.h"
16
17int ovl_want_write(struct dentry *dentry)
18{
19 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
20 return mnt_want_write(ofs->upper_mnt);
21}
22
23void ovl_drop_write(struct dentry *dentry)
24{
25 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
26 mnt_drop_write(ofs->upper_mnt);
27}
28
29struct dentry *ovl_workdir(struct dentry *dentry)
30{
31 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
32 return ofs->workdir;
33}
34
35const struct cred *ovl_override_creds(struct super_block *sb)
36{
37 struct ovl_fs *ofs = sb->s_fs_info;
38
39 return override_creds(ofs->creator_cred);
40}
41
42struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
43{
44 size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
45 struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
46
47 if (oe)
48 oe->numlower = numlower;
49
50 return oe;
51}
52
53bool ovl_dentry_remote(struct dentry *dentry)
54{
55 return dentry->d_flags &
56 (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
57 DCACHE_OP_REAL);
58}
59
60bool ovl_dentry_weird(struct dentry *dentry)
61{
62 return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
63 DCACHE_MANAGE_TRANSIT |
64 DCACHE_OP_HASH |
65 DCACHE_OP_COMPARE);
66}
67
68enum ovl_path_type ovl_path_type(struct dentry *dentry)
69{
70 struct ovl_entry *oe = dentry->d_fsdata;
71 enum ovl_path_type type = 0;
72
73 if (oe->__upperdentry) {
74 type = __OVL_PATH_UPPER;
75
76 /*
77 * Non-dir dentry can hold lower dentry from previous
78 * location.
79 */
80 if (oe->numlower && d_is_dir(dentry))
81 type |= __OVL_PATH_MERGE;
82 } else {
83 if (oe->numlower > 1)
84 type |= __OVL_PATH_MERGE;
85 }
86 return type;
87}
88
89void ovl_path_upper(struct dentry *dentry, struct path *path)
90{
91 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
92 struct ovl_entry *oe = dentry->d_fsdata;
93
94 path->mnt = ofs->upper_mnt;
95 path->dentry = ovl_upperdentry_dereference(oe);
96}
97
98void ovl_path_lower(struct dentry *dentry, struct path *path)
99{
100 struct ovl_entry *oe = dentry->d_fsdata;
101
102 *path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL };
103}
104
105enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
106{
107 enum ovl_path_type type = ovl_path_type(dentry);
108
109 if (!OVL_TYPE_UPPER(type))
110 ovl_path_lower(dentry, path);
111 else
112 ovl_path_upper(dentry, path);
113
114 return type;
115}
116
117struct dentry *ovl_dentry_upper(struct dentry *dentry)
118{
119 struct ovl_entry *oe = dentry->d_fsdata;
120
121 return ovl_upperdentry_dereference(oe);
122}
123
124static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
125{
126 return oe->numlower ? oe->lowerstack[0].dentry : NULL;
127}
128
129struct dentry *ovl_dentry_lower(struct dentry *dentry)
130{
131 struct ovl_entry *oe = dentry->d_fsdata;
132
133 return __ovl_dentry_lower(oe);
134}
135
136struct dentry *ovl_dentry_real(struct dentry *dentry)
137{
138 struct ovl_entry *oe = dentry->d_fsdata;
139 struct dentry *realdentry;
140
141 realdentry = ovl_upperdentry_dereference(oe);
142 if (!realdentry)
143 realdentry = __ovl_dentry_lower(oe);
144
145 return realdentry;
146}
147
148struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
149{
150 struct ovl_entry *oe = dentry->d_fsdata;
151
152 return oe->cache;
153}
154
155void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
156{
157 struct ovl_entry *oe = dentry->d_fsdata;
158
159 oe->cache = cache;
160}
161
162bool ovl_dentry_is_opaque(struct dentry *dentry)
163{
164 struct ovl_entry *oe = dentry->d_fsdata;
165 return oe->opaque;
166}
167
168bool ovl_dentry_is_whiteout(struct dentry *dentry)
169{
170 return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
171}
172
173void ovl_dentry_set_opaque(struct dentry *dentry)
174{
175 struct ovl_entry *oe = dentry->d_fsdata;
176
177 oe->opaque = true;
178}
179
180bool ovl_redirect_dir(struct super_block *sb)
181{
182 struct ovl_fs *ofs = sb->s_fs_info;
183
184 return ofs->config.redirect_dir;
185}
186
187void ovl_clear_redirect_dir(struct super_block *sb)
188{
189 struct ovl_fs *ofs = sb->s_fs_info;
190
191 ofs->config.redirect_dir = false;
192}
193
194const char *ovl_dentry_get_redirect(struct dentry *dentry)
195{
196 struct ovl_entry *oe = dentry->d_fsdata;
197
198 return oe->redirect;
199}
200
201void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
202{
203 struct ovl_entry *oe = dentry->d_fsdata;
204
205 kfree(oe->redirect);
206 oe->redirect = redirect;
207}
208
209void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
210{
211 struct ovl_entry *oe = dentry->d_fsdata;
212
213 WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
214 WARN_ON(oe->__upperdentry);
215 /*
216 * Make sure upperdentry is consistent before making it visible to
217 * ovl_upperdentry_dereference().
218 */
219 smp_wmb();
220 oe->__upperdentry = upperdentry;
221}
222
223void ovl_inode_init(struct inode *inode, struct inode *realinode, bool is_upper)
224{
225 WRITE_ONCE(inode->i_private, (unsigned long) realinode |
226 (is_upper ? OVL_ISUPPER_MASK : 0));
227}
228
229void ovl_inode_update(struct inode *inode, struct inode *upperinode)
230{
231 WARN_ON(!upperinode);
232 WARN_ON(!inode_unhashed(inode));
233 WRITE_ONCE(inode->i_private,
234 (unsigned long) upperinode | OVL_ISUPPER_MASK);
235 if (!S_ISDIR(upperinode->i_mode))
236 __insert_inode_hash(inode, (unsigned long) upperinode);
237}
238
239void ovl_dentry_version_inc(struct dentry *dentry)
240{
241 struct ovl_entry *oe = dentry->d_fsdata;
242
243 WARN_ON(!inode_is_locked(dentry->d_inode));
244 oe->version++;
245}
246
247u64 ovl_dentry_version_get(struct dentry *dentry)
248{
249 struct ovl_entry *oe = dentry->d_fsdata;
250
251 WARN_ON(!inode_is_locked(dentry->d_inode));
252 return oe->version;
253}
254
255bool ovl_is_whiteout(struct dentry *dentry)
256{
257 struct inode *inode = dentry->d_inode;
258
259 return inode && IS_WHITEOUT(inode);
260}
261
262struct file *ovl_path_open(struct path *path, int flags)
263{
264 return dentry_open(path, flags | O_NOATIME, current_cred());
265}