1#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
 10#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)
 15
 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 (connectable && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
 25		*max_len = BTRFS_FID_SIZE_CONNECTABLE;
 26		return 255;
 27	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
 28		*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
 29		return 255;
 30	}
 31
 32	len  = BTRFS_FID_SIZE_NON_CONNECTABLE;
 33	type = FILEID_BTRFS_WITHOUT_PARENT;
 34
 35	fid->objectid = btrfs_ino(inode);
 36	fid->root_objectid = BTRFS_I(inode)->root->objectid;
 37	fid->gen = inode->i_generation;
 38
 39	if (connectable && !S_ISDIR(inode->i_mode)) {
 40		struct inode *parent;
 41		u64 parent_root_id;
 42
 43		spin_lock(&dentry->d_lock);
 44
 45		parent = dentry->d_parent->d_inode;
 46		fid->parent_objectid = BTRFS_I(parent)->location.objectid;
 47		fid->parent_gen = parent->i_generation;
 48		parent_root_id = BTRFS_I(parent)->root->objectid;
 49
 50		spin_unlock(&dentry->d_lock);
 51
 52		if (parent_root_id != fid->root_objectid) {
 53			fid->parent_root_objectid = parent_root_id;
 54			len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
 55			type = FILEID_BTRFS_WITH_PARENT_ROOT;
 56		} else {
 57			len = BTRFS_FID_SIZE_CONNECTABLE;
 58			type = FILEID_BTRFS_WITH_PARENT;
 59		}
 60	}
 61
 62	*max_len = len;
 63	return type;
 64}
 65
 66static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
 67				       u64 root_objectid, u32 generation,
 68				       int check_generation)
 69{
 70	struct btrfs_fs_info *fs_info = btrfs_sb(sb)->fs_info;
 71	struct btrfs_root *root;
 72	struct inode *inode;
 73	struct btrfs_key key;
 74	int index;
 75	int err = 0;
 76
 77	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
 78		return ERR_PTR(-ESTALE);
 79
 80	key.objectid = root_objectid;
 81	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 82	key.offset = (u64)-1;
 83
 84	index = srcu_read_lock(&fs_info->subvol_srcu);
 85
 86	root = btrfs_read_fs_root_no_name(fs_info, &key);
 87	if (IS_ERR(root)) {
 88		err = PTR_ERR(root);
 89		goto fail;
 90	}
 91
 92	if (btrfs_root_refs(&root->root_item) == 0) {
 93		err = -ENOENT;
 94		goto fail;
 95	}
 96
 97	key.objectid = objectid;
 98	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
 99	key.offset = 0;
100
101	inode = btrfs_iget(sb, &key, root, NULL);
102	if (IS_ERR(inode)) {
103		err = PTR_ERR(inode);
104		goto fail;
105	}
106
107	srcu_read_unlock(&fs_info->subvol_srcu, index);
108
109	if (check_generation && generation != inode->i_generation) {
110		iput(inode);
111		return ERR_PTR(-ESTALE);
112	}
113
114	return d_obtain_alias(inode);
115fail:
116	srcu_read_unlock(&fs_info->subvol_srcu, index);
117	return ERR_PTR(err);
118}
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
141	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
142}
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
163	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
164}
165
166static struct dentry *btrfs_get_parent(struct dentry *child)
167{
168	struct inode *dir = child->d_inode;
169	struct btrfs_root *root = BTRFS_I(dir)->root;
170	struct btrfs_path *path;
171	struct extent_buffer *leaf;
172	struct btrfs_root_ref *ref;
173	struct btrfs_key key;
174	struct btrfs_key found_key;
175	int ret;
176
177	path = btrfs_alloc_path();
178	if (!path)
179		return ERR_PTR(-ENOMEM);
180
181	if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
182		key.objectid = root->root_key.objectid;
183		key.type = BTRFS_ROOT_BACKREF_KEY;
184		key.offset = (u64)-1;
185		root = root->fs_info->tree_root;
186	} else {
187		key.objectid = btrfs_ino(dir);
188		key.type = BTRFS_INODE_REF_KEY;
189		key.offset = (u64)-1;
190	}
191
192	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
193	if (ret < 0)
194		goto fail;
195
196	BUG_ON(ret == 0);
197	if (path->slots[0] == 0) {
198		ret = -ENOENT;
199		goto fail;
200	}
201
202	path->slots[0]--;
203	leaf = path->nodes[0];
204
205	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
206	if (found_key.objectid != key.objectid || found_key.type != key.type) {
207		ret = -ENOENT;
208		goto fail;
209	}
210
211	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
212		ref = btrfs_item_ptr(leaf, path->slots[0],
213				     struct btrfs_root_ref);
214		key.objectid = btrfs_root_ref_dirid(leaf, ref);
215	} else {
216		key.objectid = found_key.offset;
217	}
218	btrfs_free_path(path);
219
220	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
221		return btrfs_get_dentry(root->fs_info->sb, key.objectid,
222					found_key.offset, 0, 0);
223	}
224
225	key.type = BTRFS_INODE_ITEM_KEY;
226	key.offset = 0;
227	return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
228fail:
229	btrfs_free_path(path);
230	return ERR_PTR(ret);
231}
232
233static int btrfs_get_name(struct dentry *parent, char *name,
234			  struct dentry *child)
235{
236	struct inode *inode = child->d_inode;
237	struct inode *dir = parent->d_inode;
238	struct btrfs_path *path;
239	struct btrfs_root *root = BTRFS_I(dir)->root;
240	struct btrfs_inode_ref *iref;
241	struct btrfs_root_ref *rref;
242	struct extent_buffer *leaf;
243	unsigned long name_ptr;
244	struct btrfs_key key;
245	int name_len;
246	int ret;
247	u64 ino;
248
249	if (!dir || !inode)
250		return -EINVAL;
251
252	if (!S_ISDIR(dir->i_mode))
253		return -EINVAL;
254
255	ino = btrfs_ino(inode);
256
257	path = btrfs_alloc_path();
258	if (!path)
259		return -ENOMEM;
260	path->leave_spinning = 1;
261
262	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
263		key.objectid = BTRFS_I(inode)->root->root_key.objectid;
264		key.type = BTRFS_ROOT_BACKREF_KEY;
265		key.offset = (u64)-1;
266		root = root->fs_info->tree_root;
267	} else {
268		key.objectid = ino;
269		key.offset = btrfs_ino(dir);
270		key.type = BTRFS_INODE_REF_KEY;
271	}
272
273	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
274	if (ret < 0) {
275		btrfs_free_path(path);
276		return ret;
277	} else if (ret > 0) {
278		if (ino == BTRFS_FIRST_FREE_OBJECTID) {
279			path->slots[0]--;
280		} else {
281			btrfs_free_path(path);
282			return -ENOENT;
283		}
284	}
285	leaf = path->nodes[0];
286
287	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
288		rref = btrfs_item_ptr(leaf, path->slots[0],
289				     struct btrfs_root_ref);
290		name_ptr = (unsigned long)(rref + 1);
291		name_len = btrfs_root_ref_name_len(leaf, rref);
292	} else {
293		iref = btrfs_item_ptr(leaf, path->slots[0],
294				      struct btrfs_inode_ref);
295		name_ptr = (unsigned long)(iref + 1);
296		name_len = btrfs_inode_ref_name_len(leaf, iref);
297	}
298
299	read_extent_buffer(leaf, name, name_ptr, name_len);
300	btrfs_free_path(path);
301
302	/*
303	 * have to add the null termination to make sure that reconnect_path
304	 * gets the right len for strlen
305	 */
306	name[name_len] = '\0';
307
308	return 0;
309}
310
311const struct export_operations btrfs_export_ops = {
312	.encode_fh	= btrfs_encode_fh,
313	.fh_to_dentry	= btrfs_fh_to_dentry,
314	.fh_to_parent	= btrfs_fh_to_parent,
315	.get_parent	= btrfs_get_parent,
316	.get_name	= btrfs_get_name,
317};

  1#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
 10#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)
 15
 16static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 17			   struct inode *parent)
 18{
 19	struct btrfs_fid *fid = (struct btrfs_fid *)fh;
 
 20	int len = *max_len;
 21	int type;
 22
 23	if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
 24		*max_len = BTRFS_FID_SIZE_CONNECTABLE;
 25		return 255;
 26	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
 27		*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
 28		return 255;
 29	}
 30
 31	len  = BTRFS_FID_SIZE_NON_CONNECTABLE;
 32	type = FILEID_BTRFS_WITHOUT_PARENT;
 33
 34	fid->objectid = btrfs_ino(inode);
 35	fid->root_objectid = BTRFS_I(inode)->root->objectid;
 36	fid->gen = inode->i_generation;
 37
 38	if (parent) {
 
 39		u64 parent_root_id;
 40
 
 
 
 41		fid->parent_objectid = BTRFS_I(parent)->location.objectid;
 42		fid->parent_gen = parent->i_generation;
 43		parent_root_id = BTRFS_I(parent)->root->objectid;
 44
 
 
 45		if (parent_root_id != fid->root_objectid) {
 46			fid->parent_root_objectid = parent_root_id;
 47			len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
 48			type = FILEID_BTRFS_WITH_PARENT_ROOT;
 49		} else {
 50			len = BTRFS_FID_SIZE_CONNECTABLE;
 51			type = FILEID_BTRFS_WITH_PARENT;
 52		}
 53	}
 54
 55	*max_len = len;
 56	return type;
 57}
 58
 59static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
 60				       u64 root_objectid, u32 generation,
 61				       int check_generation)
 62{
 63	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 64	struct btrfs_root *root;
 65	struct inode *inode;
 66	struct btrfs_key key;
 67	int index;
 68	int err = 0;
 69
 70	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
 71		return ERR_PTR(-ESTALE);
 72
 73	key.objectid = root_objectid;
 74	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 75	key.offset = (u64)-1;
 76
 77	index = srcu_read_lock(&fs_info->subvol_srcu);
 78
 79	root = btrfs_read_fs_root_no_name(fs_info, &key);
 80	if (IS_ERR(root)) {
 81		err = PTR_ERR(root);
 82		goto fail;
 83	}
 84
 85	if (btrfs_root_refs(&root->root_item) == 0) {
 86		err = -ENOENT;
 87		goto fail;
 88	}
 89
 90	key.objectid = objectid;
 91	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
 92	key.offset = 0;
 93
 94	inode = btrfs_iget(sb, &key, root, NULL);
 95	if (IS_ERR(inode)) {
 96		err = PTR_ERR(inode);
 97		goto fail;
 98	}
 99
100	srcu_read_unlock(&fs_info->subvol_srcu, index);
101
102	if (check_generation && generation != inode->i_generation) {
103		iput(inode);
104		return ERR_PTR(-ESTALE);
105	}
106
107	return d_obtain_alias(inode);
108fail:
109	srcu_read_unlock(&fs_info->subvol_srcu, index);
110	return ERR_PTR(err);
111}
112
113static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
114					 int fh_len, int fh_type)
115{
116	struct btrfs_fid *fid = (struct btrfs_fid *) fh;
117	u64 objectid, root_objectid;
118	u32 generation;
119
120	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
121		if (fh_len !=  BTRFS_FID_SIZE_CONNECTABLE)
122			return NULL;
123		root_objectid = fid->root_objectid;
124	} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
125		if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
126			return NULL;
127		root_objectid = fid->parent_root_objectid;
128	} else
129		return NULL;
130
131	objectid = fid->parent_objectid;
132	generation = fid->parent_gen;
133
134	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
135}
136
137static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
138					 int fh_len, int fh_type)
139{
140	struct btrfs_fid *fid = (struct btrfs_fid *) fh;
141	u64 objectid, root_objectid;
142	u32 generation;
143
144	if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
145	     fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
146	    (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
147	     fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
148	    (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
149	     fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
150		return NULL;
151
152	objectid = fid->objectid;
153	root_objectid = fid->root_objectid;
154	generation = fid->gen;
155
156	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
157}
158
159static struct dentry *btrfs_get_parent(struct dentry *child)
160{
161	struct inode *dir = child->d_inode;
162	struct btrfs_root *root = BTRFS_I(dir)->root;
163	struct btrfs_path *path;
164	struct extent_buffer *leaf;
165	struct btrfs_root_ref *ref;
166	struct btrfs_key key;
167	struct btrfs_key found_key;
168	int ret;
169
170	path = btrfs_alloc_path();
171	if (!path)
172		return ERR_PTR(-ENOMEM);
173
174	if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
175		key.objectid = root->root_key.objectid;
176		key.type = BTRFS_ROOT_BACKREF_KEY;
177		key.offset = (u64)-1;
178		root = root->fs_info->tree_root;
179	} else {
180		key.objectid = btrfs_ino(dir);
181		key.type = BTRFS_INODE_REF_KEY;
182		key.offset = (u64)-1;
183	}
184
185	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
186	if (ret < 0)
187		goto fail;
188
189	BUG_ON(ret == 0); /* Key with offset of -1 found */
190	if (path->slots[0] == 0) {
191		ret = -ENOENT;
192		goto fail;
193	}
194
195	path->slots[0]--;
196	leaf = path->nodes[0];
197
198	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
199	if (found_key.objectid != key.objectid || found_key.type != key.type) {
200		ret = -ENOENT;
201		goto fail;
202	}
203
204	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
205		ref = btrfs_item_ptr(leaf, path->slots[0],
206				     struct btrfs_root_ref);
207		key.objectid = btrfs_root_ref_dirid(leaf, ref);
208	} else {
209		key.objectid = found_key.offset;
210	}
211	btrfs_free_path(path);
212
213	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
214		return btrfs_get_dentry(root->fs_info->sb, key.objectid,
215					found_key.offset, 0, 0);
216	}
217
218	key.type = BTRFS_INODE_ITEM_KEY;
219	key.offset = 0;
220	return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
221fail:
222	btrfs_free_path(path);
223	return ERR_PTR(ret);
224}
225
226static int btrfs_get_name(struct dentry *parent, char *name,
227			  struct dentry *child)
228{
229	struct inode *inode = child->d_inode;
230	struct inode *dir = parent->d_inode;
231	struct btrfs_path *path;
232	struct btrfs_root *root = BTRFS_I(dir)->root;
233	struct btrfs_inode_ref *iref;
234	struct btrfs_root_ref *rref;
235	struct extent_buffer *leaf;
236	unsigned long name_ptr;
237	struct btrfs_key key;
238	int name_len;
239	int ret;
240	u64 ino;
241
242	if (!dir || !inode)
243		return -EINVAL;
244
245	if (!S_ISDIR(dir->i_mode))
246		return -EINVAL;
247
248	ino = btrfs_ino(inode);
249
250	path = btrfs_alloc_path();
251	if (!path)
252		return -ENOMEM;
253	path->leave_spinning = 1;
254
255	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
256		key.objectid = BTRFS_I(inode)->root->root_key.objectid;
257		key.type = BTRFS_ROOT_BACKREF_KEY;
258		key.offset = (u64)-1;
259		root = root->fs_info->tree_root;
260	} else {
261		key.objectid = ino;
262		key.offset = btrfs_ino(dir);
263		key.type = BTRFS_INODE_REF_KEY;
264	}
265
266	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
267	if (ret < 0) {
268		btrfs_free_path(path);
269		return ret;
270	} else if (ret > 0) {
271		if (ino == BTRFS_FIRST_FREE_OBJECTID) {
272			path->slots[0]--;
273		} else {
274			btrfs_free_path(path);
275			return -ENOENT;
276		}
277	}
278	leaf = path->nodes[0];
279
280	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
281		rref = btrfs_item_ptr(leaf, path->slots[0],
282				     struct btrfs_root_ref);
283		name_ptr = (unsigned long)(rref + 1);
284		name_len = btrfs_root_ref_name_len(leaf, rref);
285	} else {
286		iref = btrfs_item_ptr(leaf, path->slots[0],
287				      struct btrfs_inode_ref);
288		name_ptr = (unsigned long)(iref + 1);
289		name_len = btrfs_inode_ref_name_len(leaf, iref);
290	}
291
292	read_extent_buffer(leaf, name, name_ptr, name_len);
293	btrfs_free_path(path);
294
295	/*
296	 * have to add the null termination to make sure that reconnect_path
297	 * gets the right len for strlen
298	 */
299	name[name_len] = '\0';
300
301	return 0;
302}
303
304const struct export_operations btrfs_export_ops = {
305	.encode_fh	= btrfs_encode_fh,
306	.fh_to_dentry	= btrfs_fh_to_dentry,
307	.fh_to_parent	= btrfs_fh_to_parent,
308	.get_parent	= btrfs_get_parent,
309	.get_name	= btrfs_get_name,
310};