1// SPDX-License-Identifier: GPL-2.0
  2
  3#include <linux/fs.h>
  4#include <linux/types.h>
  5#include "ctree.h"
  6#include "disk-io.h"
  7#include "btrfs_inode.h"
  8#include "print-tree.h"
  9#include "export.h"
 
 10
 11#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
 12						 parent_objectid) / 4)
 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)
 16
 17static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 18			   struct inode *parent)
 19{
 20	struct btrfs_fid *fid = (struct btrfs_fid *)fh;
 
 21	int len = *max_len;
 22	int type;
 23
 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;
 30	}
 31
 32	len  = BTRFS_FID_SIZE_NON_CONNECTABLE;
 33	type = FILEID_BTRFS_WITHOUT_PARENT;
 34
 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;
 38
 39	if (parent) {
 
 40		u64 parent_root_id;
 41
 
 
 
 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;
 
 
 45
 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;
 50		} else {
 51			len = BTRFS_FID_SIZE_CONNECTABLE;
 52			type = FILEID_BTRFS_WITH_PARENT;
 53		}
 54	}
 55
 56	*max_len = len;
 57	return type;
 58}
 59
 60static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
 61				       u64 root_objectid, u32 generation,
 62				       int check_generation)
 63{
 64	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 65	struct btrfs_root *root;
 66	struct inode *inode;
 67	struct btrfs_key key;
 68	int index;
 69	int err = 0;
 70
 71	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
 72		return ERR_PTR(-ESTALE);
 73
 74	key.objectid = root_objectid;
 75	key.type = BTRFS_ROOT_ITEM_KEY;
 76	key.offset = (u64)-1;
 77
 78	index = srcu_read_lock(&fs_info->subvol_srcu);
 79
 80	root = btrfs_read_fs_root_no_name(fs_info, &key);
 81	if (IS_ERR(root)) {
 82		err = PTR_ERR(root);
 83		goto fail;
 84	}
 85
 
 
 
 
 
 86	key.objectid = objectid;
 87	key.type = BTRFS_INODE_ITEM_KEY;
 88	key.offset = 0;
 89
 90	inode = btrfs_iget(sb, &key, root, NULL);
 91	if (IS_ERR(inode)) {
 92		err = PTR_ERR(inode);
 93		goto fail;
 94	}
 95
 96	srcu_read_unlock(&fs_info->subvol_srcu, index);
 97
 98	if (check_generation && generation != inode->i_generation) {
 99		iput(inode);
100		return ERR_PTR(-ESTALE);
101	}
102
103	return d_obtain_alias(inode);
104fail:
105	srcu_read_unlock(&fs_info->subvol_srcu, index);
106	return ERR_PTR(err);
107}
108
109static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
110					 int fh_len, int fh_type)
111{
112	struct btrfs_fid *fid = (struct btrfs_fid *) fh;
113	u64 objectid, root_objectid;
114	u32 generation;
115
116	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
117		if (fh_len <  BTRFS_FID_SIZE_CONNECTABLE)
118			return NULL;
119		root_objectid = fid->root_objectid;
120	} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
121		if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
122			return NULL;
123		root_objectid = fid->parent_root_objectid;
124	} else
125		return NULL;
126
127	objectid = fid->parent_objectid;
128	generation = fid->parent_gen;
129
130	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
131}
132
133static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
134					 int fh_len, int fh_type)
135{
136	struct btrfs_fid *fid = (struct btrfs_fid *) fh;
137	u64 objectid, root_objectid;
138	u32 generation;
139
140	if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
141	     fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
142	    (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
143	     fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
144	    (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
145	     fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
146		return NULL;
147
148	objectid = fid->objectid;
149	root_objectid = fid->root_objectid;
150	generation = fid->gen;
151
152	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
153}
154
155static struct dentry *btrfs_get_parent(struct dentry *child)
156{
157	struct inode *dir = d_inode(child);
158	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
159	struct btrfs_root *root = BTRFS_I(dir)->root;
160	struct btrfs_path *path;
161	struct extent_buffer *leaf;
162	struct btrfs_root_ref *ref;
163	struct btrfs_key key;
164	struct btrfs_key found_key;
165	int ret;
166
167	path = btrfs_alloc_path();
168	if (!path)
169		return ERR_PTR(-ENOMEM);
170
171	if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) {
172		key.objectid = root->root_key.objectid;
173		key.type = BTRFS_ROOT_BACKREF_KEY;
174		key.offset = (u64)-1;
175		root = fs_info->tree_root;
176	} else {
177		key.objectid = btrfs_ino(BTRFS_I(dir));
178		key.type = BTRFS_INODE_REF_KEY;
179		key.offset = (u64)-1;
180	}
181
182	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
183	if (ret < 0)
184		goto fail;
185
186	BUG_ON(ret == 0); /* Key with offset of -1 found */
187	if (path->slots[0] == 0) {
188		ret = -ENOENT;
189		goto fail;
190	}
191
192	path->slots[0]--;
193	leaf = path->nodes[0];
194
195	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
196	if (found_key.objectid != key.objectid || found_key.type != key.type) {
197		ret = -ENOENT;
198		goto fail;
199	}
200
201	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
202		ref = btrfs_item_ptr(leaf, path->slots[0],
203				     struct btrfs_root_ref);
204		key.objectid = btrfs_root_ref_dirid(leaf, ref);
205	} else {
206		key.objectid = found_key.offset;
207	}
208	btrfs_free_path(path);
209
210	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
211		return btrfs_get_dentry(fs_info->sb, key.objectid,
212					found_key.offset, 0, 0);
213	}
214
215	key.type = BTRFS_INODE_ITEM_KEY;
216	key.offset = 0;
217	return d_obtain_alias(btrfs_iget(fs_info->sb, &key, root, NULL));
218fail:
219	btrfs_free_path(path);
220	return ERR_PTR(ret);
221}
222
223static int btrfs_get_name(struct dentry *parent, char *name,
224			  struct dentry *child)
225{
226	struct inode *inode = d_inode(child);
227	struct inode *dir = d_inode(parent);
228	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
229	struct btrfs_path *path;
230	struct btrfs_root *root = BTRFS_I(dir)->root;
231	struct btrfs_inode_ref *iref;
232	struct btrfs_root_ref *rref;
233	struct extent_buffer *leaf;
234	unsigned long name_ptr;
235	struct btrfs_key key;
236	int name_len;
237	int ret;
238	u64 ino;
239
 
 
 
240	if (!S_ISDIR(dir->i_mode))
241		return -EINVAL;
242
243	ino = btrfs_ino(BTRFS_I(inode));
244
245	path = btrfs_alloc_path();
246	if (!path)
247		return -ENOMEM;
248	path->leave_spinning = 1;
249
250	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
251		key.objectid = BTRFS_I(inode)->root->root_key.objectid;
252		key.type = BTRFS_ROOT_BACKREF_KEY;
253		key.offset = (u64)-1;
254		root = fs_info->tree_root;
255	} else {
256		key.objectid = ino;
257		key.offset = btrfs_ino(BTRFS_I(dir));
258		key.type = BTRFS_INODE_REF_KEY;
259	}
260
261	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
262	if (ret < 0) {
263		btrfs_free_path(path);
264		return ret;
265	} else if (ret > 0) {
266		if (ino == BTRFS_FIRST_FREE_OBJECTID) {
267			path->slots[0]--;
268		} else {
269			btrfs_free_path(path);
270			return -ENOENT;
271		}
272	}
273	leaf = path->nodes[0];
274
275	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
276		rref = btrfs_item_ptr(leaf, path->slots[0],
277				     struct btrfs_root_ref);
278		name_ptr = (unsigned long)(rref + 1);
279		name_len = btrfs_root_ref_name_len(leaf, rref);
280	} else {
281		iref = btrfs_item_ptr(leaf, path->slots[0],
282				      struct btrfs_inode_ref);
283		name_ptr = (unsigned long)(iref + 1);
284		name_len = btrfs_inode_ref_name_len(leaf, iref);
285	}
286
287	read_extent_buffer(leaf, name, name_ptr, name_len);
288	btrfs_free_path(path);
289
290	/*
291	 * have to add the null termination to make sure that reconnect_path
292	 * gets the right len for strlen
293	 */
294	name[name_len] = '\0';
295
296	return 0;
297}
298
299const struct export_operations btrfs_export_ops = {
300	.encode_fh	= btrfs_encode_fh,
301	.fh_to_dentry	= btrfs_fh_to_dentry,
302	.fh_to_parent	= btrfs_fh_to_parent,
303	.get_parent	= btrfs_get_parent,
304	.get_name	= btrfs_get_name,
305};

 
 
  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};