1 // SPDX-License-Identifier: GPL-2.0
4 #include <linux/types.h>
7 #include "btrfs_inode.h"
8 #include "print-tree.h"
11 #define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
13 #define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \
14 parent_root_objectid) / 4)
15 #define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4)
17 static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
20 struct btrfs_fid *fid = (struct btrfs_fid *)fh;
24 if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
25 *max_len = BTRFS_FID_SIZE_CONNECTABLE;
26 return FILEID_INVALID;
27 } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
28 *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
29 return FILEID_INVALID;
32 len = BTRFS_FID_SIZE_NON_CONNECTABLE;
33 type = FILEID_BTRFS_WITHOUT_PARENT;
35 fid->objectid = btrfs_ino(BTRFS_I(inode));
36 fid->root_objectid = BTRFS_I(inode)->root->root_key.objectid;
37 fid->gen = inode->i_generation;
42 fid->parent_objectid = BTRFS_I(parent)->location.objectid;
43 fid->parent_gen = parent->i_generation;
44 parent_root_id = BTRFS_I(parent)->root->root_key.objectid;
46 if (parent_root_id != fid->root_objectid) {
47 fid->parent_root_objectid = parent_root_id;
48 len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
49 type = FILEID_BTRFS_WITH_PARENT_ROOT;
51 len = BTRFS_FID_SIZE_CONNECTABLE;
52 type = FILEID_BTRFS_WITH_PARENT;
60 struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
61 u64 root_objectid, u64 generation,
64 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
65 struct btrfs_root *root;
68 if (objectid < BTRFS_FIRST_FREE_OBJECTID)
69 return ERR_PTR(-ESTALE);
71 root = btrfs_get_fs_root(fs_info, root_objectid, true);
73 return ERR_CAST(root);
75 inode = btrfs_iget(sb, objectid, root);
78 return ERR_CAST(inode);
80 if (check_generation && generation != inode->i_generation) {
82 return ERR_PTR(-ESTALE);
85 return d_obtain_alias(inode);
88 static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
89 int fh_len, int fh_type)
91 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
92 u64 objectid, root_objectid;
95 if (fh_type == FILEID_BTRFS_WITH_PARENT) {
96 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE)
98 root_objectid = fid->root_objectid;
99 } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
100 if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
102 root_objectid = fid->parent_root_objectid;
106 objectid = fid->parent_objectid;
107 generation = fid->parent_gen;
109 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
112 static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
113 int fh_len, int fh_type)
115 struct btrfs_fid *fid = (struct btrfs_fid *) fh;
116 u64 objectid, root_objectid;
119 if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
120 fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
121 (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
122 fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
123 (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
124 fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
127 objectid = fid->objectid;
128 root_objectid = fid->root_objectid;
129 generation = fid->gen;
131 return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
134 struct dentry *btrfs_get_parent(struct dentry *child)
136 struct inode *dir = d_inode(child);
137 struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
138 struct btrfs_root *root = BTRFS_I(dir)->root;
139 struct btrfs_path *path;
140 struct extent_buffer *leaf;
141 struct btrfs_root_ref *ref;
142 struct btrfs_key key;
143 struct btrfs_key found_key;
146 path = btrfs_alloc_path();
148 return ERR_PTR(-ENOMEM);
150 if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) {
151 key.objectid = root->root_key.objectid;
152 key.type = BTRFS_ROOT_BACKREF_KEY;
153 key.offset = (u64)-1;
154 root = fs_info->tree_root;
156 key.objectid = btrfs_ino(BTRFS_I(dir));
157 key.type = BTRFS_INODE_REF_KEY;
158 key.offset = (u64)-1;
161 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
166 * Key with offset of -1 found, there would have to exist an
167 * inode with such number or a root with such id.
173 if (path->slots[0] == 0) {
179 leaf = path->nodes[0];
181 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
182 if (found_key.objectid != key.objectid || found_key.type != key.type) {
187 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
188 ref = btrfs_item_ptr(leaf, path->slots[0],
189 struct btrfs_root_ref);
190 key.objectid = btrfs_root_ref_dirid(leaf, ref);
192 key.objectid = found_key.offset;
194 btrfs_free_path(path);
196 if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
197 return btrfs_get_dentry(fs_info->sb, key.objectid,
198 found_key.offset, 0, 0);
201 return d_obtain_alias(btrfs_iget(fs_info->sb, key.objectid, root));
203 btrfs_free_path(path);
207 static int btrfs_get_name(struct dentry *parent, char *name,
208 struct dentry *child)
210 struct inode *inode = d_inode(child);
211 struct inode *dir = d_inode(parent);
212 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
213 struct btrfs_path *path;
214 struct btrfs_root *root = BTRFS_I(dir)->root;
215 struct btrfs_inode_ref *iref;
216 struct btrfs_root_ref *rref;
217 struct extent_buffer *leaf;
218 unsigned long name_ptr;
219 struct btrfs_key key;
224 if (!S_ISDIR(dir->i_mode))
227 ino = btrfs_ino(BTRFS_I(inode));
229 path = btrfs_alloc_path();
232 path->leave_spinning = 1;
234 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
235 key.objectid = BTRFS_I(inode)->root->root_key.objectid;
236 key.type = BTRFS_ROOT_BACKREF_KEY;
237 key.offset = (u64)-1;
238 root = fs_info->tree_root;
241 key.offset = btrfs_ino(BTRFS_I(dir));
242 key.type = BTRFS_INODE_REF_KEY;
245 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
247 btrfs_free_path(path);
249 } else if (ret > 0) {
250 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
253 btrfs_free_path(path);
257 leaf = path->nodes[0];
259 if (ino == BTRFS_FIRST_FREE_OBJECTID) {
260 rref = btrfs_item_ptr(leaf, path->slots[0],
261 struct btrfs_root_ref);
262 name_ptr = (unsigned long)(rref + 1);
263 name_len = btrfs_root_ref_name_len(leaf, rref);
265 iref = btrfs_item_ptr(leaf, path->slots[0],
266 struct btrfs_inode_ref);
267 name_ptr = (unsigned long)(iref + 1);
268 name_len = btrfs_inode_ref_name_len(leaf, iref);
271 read_extent_buffer(leaf, name, name_ptr, name_len);
272 btrfs_free_path(path);
275 * have to add the null termination to make sure that reconnect_path
276 * gets the right len for strlen
278 name[name_len] = '\0';
283 const struct export_operations btrfs_export_ops = {
284 .encode_fh = btrfs_encode_fh,
285 .fh_to_dentry = btrfs_fh_to_dentry,
286 .fh_to_parent = btrfs_fh_to_parent,
287 .get_parent = btrfs_get_parent,
288 .get_name = btrfs_get_name,