blob: ba5c3fd5ab8c89e3057aa612f1bd929c1589b2b3 [file] [log] [blame]
Balaji Raobe6e8dc2008-07-21 02:01:56 +05301#include <linux/fs.h>
2#include <linux/types.h>
3#include "ctree.h"
4#include "disk-io.h"
5#include "btrfs_inode.h"
6#include "print-tree.h"
7#include "export.h"
8#include "compat.h"
9
Chris Masond3977122009-01-05 21:25:51 -050010#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
11 parent_objectid) / 4)
12#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \
13 parent_root_objectid) / 4)
14#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4)
Balaji Raobe6e8dc2008-07-21 02:01:56 +053015
16static int btrfs_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
17 int connectable)
18{
19 struct btrfs_fid *fid = (struct btrfs_fid *)fh;
20 struct inode *inode = dentry->d_inode;
21 int len = *max_len;
22 int type;
23
24 if ((len < BTRFS_FID_SIZE_NON_CONNECTABLE) ||
25 (connectable && len < BTRFS_FID_SIZE_CONNECTABLE))
26 return 255;
27
28 len = BTRFS_FID_SIZE_NON_CONNECTABLE;
29 type = FILEID_BTRFS_WITHOUT_PARENT;
30
Yan, Zheng76dda932009-09-21 16:00:26 -040031 fid->objectid = inode->i_ino;
Balaji Raobe6e8dc2008-07-21 02:01:56 +053032 fid->root_objectid = BTRFS_I(inode)->root->objectid;
33 fid->gen = inode->i_generation;
34
35 if (connectable && !S_ISDIR(inode->i_mode)) {
36 struct inode *parent;
37 u64 parent_root_id;
38
39 spin_lock(&dentry->d_lock);
40
41 parent = dentry->d_parent->d_inode;
42 fid->parent_objectid = BTRFS_I(parent)->location.objectid;
43 fid->parent_gen = parent->i_generation;
44 parent_root_id = BTRFS_I(parent)->root->objectid;
45
46 spin_unlock(&dentry->d_lock);
47
48 if (parent_root_id != fid->root_objectid) {
49 fid->parent_root_objectid = parent_root_id;
50 len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
51 type = FILEID_BTRFS_WITH_PARENT_ROOT;
52 } else {
53 len = BTRFS_FID_SIZE_CONNECTABLE;
54 type = FILEID_BTRFS_WITH_PARENT;
55 }
56 }
57
58 *max_len = len;
59 return type;
60}
61
62static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
Yan, Zheng76dda932009-09-21 16:00:26 -040063 u64 root_objectid, u32 generation,
64 int check_generation)
Balaji Raobe6e8dc2008-07-21 02:01:56 +053065{
Yan, Zheng76dda932009-09-21 16:00:26 -040066 struct btrfs_fs_info *fs_info = btrfs_sb(sb)->fs_info;
Balaji Raobe6e8dc2008-07-21 02:01:56 +053067 struct btrfs_root *root;
Yan, Zheng76dda932009-09-21 16:00:26 -040068 struct dentry *dentry;
Balaji Raobe6e8dc2008-07-21 02:01:56 +053069 struct inode *inode;
Balaji Raobe6e8dc2008-07-21 02:01:56 +053070 struct btrfs_key key;
Yan, Zheng76dda932009-09-21 16:00:26 -040071 int index;
72 int err = 0;
73
74 if (objectid < BTRFS_FIRST_FREE_OBJECTID)
75 return ERR_PTR(-ESTALE);
Balaji Raobe6e8dc2008-07-21 02:01:56 +053076
David Woodhouse2d4d9fbd2008-08-19 22:20:17 +010077 key.objectid = root_objectid;
78 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
79 key.offset = (u64)-1;
80
Yan, Zheng76dda932009-09-21 16:00:26 -040081 index = srcu_read_lock(&fs_info->subvol_srcu);
82
83 root = btrfs_read_fs_root_no_name(fs_info, &key);
84 if (IS_ERR(root)) {
85 err = PTR_ERR(root);
86 goto fail;
87 }
88
89 if (btrfs_root_refs(&root->root_item) == 0) {
90 err = -ENOENT;
91 goto fail;
92 }
David Woodhouse2d4d9fbd2008-08-19 22:20:17 +010093
Balaji Raobe6e8dc2008-07-21 02:01:56 +053094 key.objectid = objectid;
95 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
96 key.offset = 0;
97
Yan Zheng5d4f98a2009-06-10 10:45:14 -040098 inode = btrfs_iget(sb, &key, root);
Yan, Zheng76dda932009-09-21 16:00:26 -040099 if (IS_ERR(inode)) {
100 err = PTR_ERR(inode);
101 goto fail;
102 }
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530103
Yan, Zheng76dda932009-09-21 16:00:26 -0400104 srcu_read_unlock(&fs_info->subvol_srcu, index);
105
106 if (check_generation && generation != inode->i_generation) {
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530107 iput(inode);
108 return ERR_PTR(-ESTALE);
109 }
110
Yan, Zheng76dda932009-09-21 16:00:26 -0400111 dentry = d_obtain_alias(inode);
112 if (!IS_ERR(dentry))
113 dentry->d_op = &btrfs_dentry_operations;
114 return dentry;
115fail:
116 srcu_read_unlock(&fs_info->subvol_srcu, index);
117 return ERR_PTR(err);
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530118}
119
120static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
121 int fh_len, int fh_type)
122{
123 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
124 u64 objectid, root_objectid;
125 u32 generation;
126
127 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
128 if (fh_len != BTRFS_FID_SIZE_CONNECTABLE)
129 return NULL;
130 root_objectid = fid->root_objectid;
131 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
132 if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
133 return NULL;
134 root_objectid = fid->parent_root_objectid;
135 } else
136 return NULL;
137
138 objectid = fid->parent_objectid;
139 generation = fid->parent_gen;
140
Yan, Zheng76dda932009-09-21 16:00:26 -0400141 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530142}
143
144static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
145 int fh_len, int fh_type)
146{
147 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
148 u64 objectid, root_objectid;
149 u32 generation;
150
151 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
152 fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
153 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
154 fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
155 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
156 fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
157 return NULL;
158
159 objectid = fid->objectid;
160 root_objectid = fid->root_objectid;
161 generation = fid->gen;
162
Yan, Zheng76dda932009-09-21 16:00:26 -0400163 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530164}
165
166static struct dentry *btrfs_get_parent(struct dentry *child)
167{
168 struct inode *dir = child->d_inode;
Yan, Zheng76dda932009-09-21 16:00:26 -0400169 static struct dentry *dentry;
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530170 struct btrfs_root *root = BTRFS_I(dir)->root;
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530171 struct btrfs_path *path;
172 struct extent_buffer *leaf;
Yan, Zheng76dda932009-09-21 16:00:26 -0400173 struct btrfs_root_ref *ref;
174 struct btrfs_key key;
175 struct btrfs_key found_key;
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530176 int ret;
177
178 path = btrfs_alloc_path();
179
Yan, Zheng76dda932009-09-21 16:00:26 -0400180 if (dir->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
181 key.objectid = root->root_key.objectid;
182 key.type = BTRFS_ROOT_BACKREF_KEY;
183 key.offset = (u64)-1;
184 root = root->fs_info->tree_root;
185 } else {
186 key.objectid = dir->i_ino;
187 key.type = BTRFS_INODE_REF_KEY;
188 key.offset = (u64)-1;
189 }
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530190
David Woodhouse87acb4e2008-08-18 22:50:22 +0100191 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
Yan, Zheng76dda932009-09-21 16:00:26 -0400192 if (ret < 0)
193 goto fail;
194
195 BUG_ON(ret == 0);
196 if (path->slots[0] == 0) {
197 ret = -ENOENT;
198 goto fail;
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530199 }
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530200
Yan, Zheng76dda932009-09-21 16:00:26 -0400201 path->slots[0]--;
202 leaf = path->nodes[0];
203
204 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
205 if (found_key.objectid != key.objectid || found_key.type != key.type) {
206 ret = -ENOENT;
207 goto fail;
208 }
209
210 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
211 ref = btrfs_item_ptr(leaf, path->slots[0],
212 struct btrfs_root_ref);
213 key.objectid = btrfs_root_ref_dirid(leaf, ref);
214 } else {
215 key.objectid = found_key.offset;
216 }
David Woodhouse87acb4e2008-08-18 22:50:22 +0100217 btrfs_free_path(path);
218
Yan, Zheng76dda932009-09-21 16:00:26 -0400219 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
220 return btrfs_get_dentry(root->fs_info->sb, key.objectid,
221 found_key.offset, 0, 0);
222 }
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530223
Yan, Zheng76dda932009-09-21 16:00:26 -0400224 key.type = BTRFS_INODE_ITEM_KEY;
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530225 key.offset = 0;
Yan, Zheng76dda932009-09-21 16:00:26 -0400226 dentry = d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root));
227 if (!IS_ERR(dentry))
228 dentry->d_op = &btrfs_dentry_operations;
229 return dentry;
230fail:
231 btrfs_free_path(path);
232 return ERR_PTR(ret);
Balaji Raobe6e8dc2008-07-21 02:01:56 +0530233}
234
235const struct export_operations btrfs_export_ops = {
236 .encode_fh = btrfs_encode_fh,
237 .fh_to_dentry = btrfs_fh_to_dentry,
238 .fh_to_parent = btrfs_fh_to_parent,
239 .get_parent = btrfs_get_parent,
240};