1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
#include <linux/fs.h>
#include <linux/types.h>
#include "ctree.h"
#include "disk-io.h"
#include "btrfs_inode.h"
#include "print-tree.h"
#include "export.h"
#include "compat.h"
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
#define FILEID_BTRFS_WITHOUT_PARENT 0x4d
#define FILEID_BTRFS_WITH_PARENT 0x4e
#define FILEID_BTRFS_WITH_PARENT_ROOT 0x4f
#endif
#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, parent_objectid)/4)
#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, parent_root_objectid)/4)
#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid)/4)
static int btrfs_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
int connectable)
{
struct btrfs_fid *fid = (struct btrfs_fid *)fh;
struct inode *inode = dentry->d_inode;
int len = *max_len;
int type;
if ((len < BTRFS_FID_SIZE_NON_CONNECTABLE) ||
(connectable && len < BTRFS_FID_SIZE_CONNECTABLE))
return 255;
len = BTRFS_FID_SIZE_NON_CONNECTABLE;
type = FILEID_BTRFS_WITHOUT_PARENT;
fid->objectid = BTRFS_I(inode)->location.objectid;
fid->root_objectid = BTRFS_I(inode)->root->objectid;
fid->gen = inode->i_generation;
if (connectable && !S_ISDIR(inode->i_mode)) {
struct inode *parent;
u64 parent_root_id;
spin_lock(&dentry->d_lock);
parent = dentry->d_parent->d_inode;
fid->parent_objectid = BTRFS_I(parent)->location.objectid;
fid->parent_gen = parent->i_generation;
parent_root_id = BTRFS_I(parent)->root->objectid;
spin_unlock(&dentry->d_lock);
if (parent_root_id != fid->root_objectid) {
fid->parent_root_objectid = parent_root_id;
len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
type = FILEID_BTRFS_WITH_PARENT_ROOT;
} else {
len = BTRFS_FID_SIZE_CONNECTABLE;
type = FILEID_BTRFS_WITH_PARENT;
}
}
*max_len = len;
return type;
}
static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
u64 root_objectid, u32 generation)
{
struct btrfs_root *root;
struct inode *inode;
struct dentry *result;
struct btrfs_key key;
key.objectid = root_objectid;
btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
key.offset = (u64)-1;
root = btrfs_read_fs_root_no_name(btrfs_sb(sb)->fs_info, &key);
if (IS_ERR(root))
return ERR_CAST(root);
key.objectid = objectid;
btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
key.offset = 0;
inode = btrfs_iget(sb, &key, root, NULL);
if (IS_ERR(inode))
return (void *)inode;
if (generation != inode->i_generation) {
iput(inode);
return ERR_PTR(-ESTALE);
}
result = d_obtain_alias(inode);
if (!result)
return ERR_PTR(-ENOMEM);
return result;
}
static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
int fh_len, int fh_type)
{
struct btrfs_fid *fid = (struct btrfs_fid *) fh;
u64 objectid, root_objectid;
u32 generation;
if (fh_type == FILEID_BTRFS_WITH_PARENT) {
if (fh_len != BTRFS_FID_SIZE_CONNECTABLE)
return NULL;
root_objectid = fid->root_objectid;
} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
return NULL;
root_objectid = fid->parent_root_objectid;
} else
return NULL;
objectid = fid->parent_objectid;
generation = fid->parent_gen;
return btrfs_get_dentry(sb, objectid, root_objectid, generation);
}
static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
int fh_len, int fh_type)
{
struct btrfs_fid *fid = (struct btrfs_fid *) fh;
u64 objectid, root_objectid;
u32 generation;
if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
(fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
(fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
return NULL;
objectid = fid->objectid;
root_objectid = fid->root_objectid;
generation = fid->gen;
return btrfs_get_dentry(sb, objectid, root_objectid, generation);
}
static struct dentry *btrfs_get_parent(struct dentry *child)
{
struct inode *dir = child->d_inode;
struct inode *inode;
struct dentry *parent;
struct btrfs_root *root = BTRFS_I(dir)->root;
struct btrfs_key key;
struct btrfs_path *path;
struct extent_buffer *leaf;
int slot;
u64 objectid;
int ret;
path = btrfs_alloc_path();
key.objectid = dir->i_ino;
btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
leaf = path->nodes[0];
slot = path->slots[0];
if (ret < 0 || slot == 0) {
btrfs_free_path(path);
goto out;
}
/* btrfs_search_slot() returns the slot where we'd want to insert
an INODE_REF_KEY for parent inode #0xFFFFFFFFFFFFFFFF. The _real_
one, telling us what the parent inode _actually_ is, will be in
the slot _before_ the one that btrfs_search_slot() returns. */
slot--;
btrfs_item_key_to_cpu(leaf, &key, slot);
btrfs_free_path(path);
if (key.objectid != dir->i_ino || key.type != BTRFS_INODE_REF_KEY)
goto out;
objectid = key.offset;
/* If we are already at the root of a subvol, return the real root */
if (objectid == dir->i_ino)
return dget(dir->i_sb->s_root);
/* Build a new key for the inode item */
key.objectid = objectid;
btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
key.offset = 0;
inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
parent = d_obtain_alias(inode);
if (!parent)
parent = ERR_PTR(-ENOMEM);
return parent;
out:
btrfs_free_path(path);
return ERR_PTR(-EINVAL);
}
const struct export_operations btrfs_export_ops = {
.encode_fh = btrfs_encode_fh,
.fh_to_dentry = btrfs_fh_to_dentry,
.fh_to_parent = btrfs_fh_to_parent,
.get_parent = btrfs_get_parent,
};
|
