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
 60struct 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
 68	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
 69		return ERR_PTR(-ESTALE);
 70
 71	root = btrfs_get_fs_root(fs_info, root_objectid, true);
 72	if (IS_ERR(root))
 73		return ERR_CAST(root);
 74
 75	inode = btrfs_iget(sb, objectid, root);
 76	btrfs_put_root(root);
 77	if (IS_ERR(inode))
 78		return ERR_CAST(inode);
 79
 80	if (check_generation && generation != inode->i_generation) {
 81		iput(inode);
 82		return ERR_PTR(-ESTALE);
 83	}
 84
 85	return d_obtain_alias(inode);
 86}
 87
 88static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 89					 int fh_len, int fh_type)
 90{
 91	struct btrfs_fid *fid = (struct btrfs_fid *) fh;
 92	u64 objectid, root_objectid;
 93	u32 generation;
 94
 95	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
 96		if (fh_len <  BTRFS_FID_SIZE_CONNECTABLE)
 97			return NULL;
 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)
101			return NULL;
102		root_objectid = fid->parent_root_objectid;
103	} else
104		return NULL;
105
106	objectid = fid->parent_objectid;
107	generation = fid->parent_gen;
108
109	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
110}
111
112static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
113					 int fh_len, int fh_type)
114{
115	struct btrfs_fid *fid = (struct btrfs_fid *) fh;
116	u64 objectid, root_objectid;
117	u32 generation;
118
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))
125		return NULL;
126
127	objectid = fid->objectid;
128	root_objectid = fid->root_objectid;
129	generation = fid->gen;
130
131	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
132}
133
134struct dentry *btrfs_get_parent(struct dentry *child)
135{
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;
144	int ret;
145
146	path = btrfs_alloc_path();
147	if (!path)
148		return ERR_PTR(-ENOMEM);
149
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;
155	} else {
156		key.objectid = btrfs_ino(BTRFS_I(dir));
157		key.type = BTRFS_INODE_REF_KEY;
158		key.offset = (u64)-1;
159	}
160
161	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
162	if (ret < 0)
163		goto fail;
164
165	BUG_ON(ret == 0); /* Key with offset of -1 found */
166	if (path->slots[0] == 0) {
167		ret = -ENOENT;
168		goto fail;
169	}
170
171	path->slots[0]--;
172	leaf = path->nodes[0];
173
174	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
175	if (found_key.objectid != key.objectid || found_key.type != key.type) {
176		ret = -ENOENT;
177		goto fail;
178	}
179
180	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
181		ref = btrfs_item_ptr(leaf, path->slots[0],
182				     struct btrfs_root_ref);
183		key.objectid = btrfs_root_ref_dirid(leaf, ref);
184	} else {
185		key.objectid = found_key.offset;
186	}
187	btrfs_free_path(path);
188
189	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
190		return btrfs_get_dentry(fs_info->sb, key.objectid,
191					found_key.offset, 0, 0);
192	}
193
194	return d_obtain_alias(btrfs_iget(fs_info->sb, key.objectid, root));
195fail:
196	btrfs_free_path(path);
197	return ERR_PTR(ret);
198}
199
200static int btrfs_get_name(struct dentry *parent, char *name,
201			  struct dentry *child)
202{
203	struct inode *inode = d_inode(child);
204	struct inode *dir = d_inode(parent);
205	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
206	struct btrfs_path *path;
207	struct btrfs_root *root = BTRFS_I(dir)->root;
208	struct btrfs_inode_ref *iref;
209	struct btrfs_root_ref *rref;
210	struct extent_buffer *leaf;
211	unsigned long name_ptr;
212	struct btrfs_key key;
213	int name_len;
214	int ret;
215	u64 ino;
216
217	if (!S_ISDIR(dir->i_mode))
218		return -EINVAL;
219
220	ino = btrfs_ino(BTRFS_I(inode));
221
222	path = btrfs_alloc_path();
223	if (!path)
224		return -ENOMEM;
225	path->leave_spinning = 1;
226
227	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
228		key.objectid = BTRFS_I(inode)->root->root_key.objectid;
229		key.type = BTRFS_ROOT_BACKREF_KEY;
230		key.offset = (u64)-1;
231		root = fs_info->tree_root;
232	} else {
233		key.objectid = ino;
234		key.offset = btrfs_ino(BTRFS_I(dir));
235		key.type = BTRFS_INODE_REF_KEY;
236	}
237
238	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
239	if (ret < 0) {
240		btrfs_free_path(path);
241		return ret;
242	} else if (ret > 0) {
243		if (ino == BTRFS_FIRST_FREE_OBJECTID) {
244			path->slots[0]--;
245		} else {
246			btrfs_free_path(path);
247			return -ENOENT;
248		}
249	}
250	leaf = path->nodes[0];
251
252	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
253		rref = btrfs_item_ptr(leaf, path->slots[0],
254				     struct btrfs_root_ref);
255		name_ptr = (unsigned long)(rref + 1);
256		name_len = btrfs_root_ref_name_len(leaf, rref);
257	} else {
258		iref = btrfs_item_ptr(leaf, path->slots[0],
259				      struct btrfs_inode_ref);
260		name_ptr = (unsigned long)(iref + 1);
261		name_len = btrfs_inode_ref_name_len(leaf, iref);
262	}
263
264	read_extent_buffer(leaf, name, name_ptr, name_len);
265	btrfs_free_path(path);
266
267	/*
268	 * have to add the null termination to make sure that reconnect_path
269	 * gets the right len for strlen
270	 */
271	name[name_len] = '\0';
272
273	return 0;
274}
275
276const struct export_operations btrfs_export_ops = {
277	.encode_fh	= btrfs_encode_fh,
278	.fh_to_dentry	= btrfs_fh_to_dentry,
279	.fh_to_parent	= btrfs_fh_to_parent,
280	.get_parent	= btrfs_get_parent,
281	.get_name	= btrfs_get_name,
282};

  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
 60struct 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
 68	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
 69		return ERR_PTR(-ESTALE);
 70
 71	root = btrfs_get_fs_root(fs_info, root_objectid, true);
 72	if (IS_ERR(root))
 73		return ERR_CAST(root);
 74
 75	inode = btrfs_iget(sb, objectid, root);
 76	btrfs_put_root(root);
 77	if (IS_ERR(inode))
 78		return ERR_CAST(inode);
 79
 80	if (check_generation && generation != inode->i_generation) {
 81		iput(inode);
 82		return ERR_PTR(-ESTALE);
 83	}
 84
 85	return d_obtain_alias(inode);
 86}
 87
 88static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 89					 int fh_len, int fh_type)
 90{
 91	struct btrfs_fid *fid = (struct btrfs_fid *) fh;
 92	u64 objectid, root_objectid;
 93	u32 generation;
 94
 95	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
 96		if (fh_len <  BTRFS_FID_SIZE_CONNECTABLE)
 97			return NULL;
 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)
101			return NULL;
102		root_objectid = fid->parent_root_objectid;
103	} else
104		return NULL;
105
106	objectid = fid->parent_objectid;
107	generation = fid->parent_gen;
108
109	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
110}
111
112static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
113					 int fh_len, int fh_type)
114{
115	struct btrfs_fid *fid = (struct btrfs_fid *) fh;
116	u64 objectid, root_objectid;
117	u32 generation;
118
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))
125		return NULL;
126
127	objectid = fid->objectid;
128	root_objectid = fid->root_objectid;
129	generation = fid->gen;
130
131	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
132}
133
134struct dentry *btrfs_get_parent(struct dentry *child)
135{
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;
144	int ret;
145
146	path = btrfs_alloc_path();
147	if (!path)
148		return ERR_PTR(-ENOMEM);
149
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;
155	} else {
156		key.objectid = btrfs_ino(BTRFS_I(dir));
157		key.type = BTRFS_INODE_REF_KEY;
158		key.offset = (u64)-1;
159	}
160
161	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
162	if (ret < 0)
163		goto fail;
164
165	BUG_ON(ret == 0); /* Key with offset of -1 found */
166	if (path->slots[0] == 0) {
167		ret = -ENOENT;
168		goto fail;
169	}
170
171	path->slots[0]--;
172	leaf = path->nodes[0];
173
174	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
175	if (found_key.objectid != key.objectid || found_key.type != key.type) {
176		ret = -ENOENT;
177		goto fail;
178	}
179
180	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
181		ref = btrfs_item_ptr(leaf, path->slots[0],
182				     struct btrfs_root_ref);
183		key.objectid = btrfs_root_ref_dirid(leaf, ref);
184	} else {
185		key.objectid = found_key.offset;
186	}
187	btrfs_free_path(path);
188
189	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
190		return btrfs_get_dentry(fs_info->sb, key.objectid,
191					found_key.offset, 0, 0);
192	}
193
194	return d_obtain_alias(btrfs_iget(fs_info->sb, key.objectid, root));
195fail:
196	btrfs_free_path(path);
197	return ERR_PTR(ret);
198}
199
200static int btrfs_get_name(struct dentry *parent, char *name,
201			  struct dentry *child)
202{
203	struct inode *inode = d_inode(child);
204	struct inode *dir = d_inode(parent);
205	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
206	struct btrfs_path *path;
207	struct btrfs_root *root = BTRFS_I(dir)->root;
208	struct btrfs_inode_ref *iref;
209	struct btrfs_root_ref *rref;
210	struct extent_buffer *leaf;
211	unsigned long name_ptr;
212	struct btrfs_key key;
213	int name_len;
214	int ret;
215	u64 ino;
216
217	if (!S_ISDIR(dir->i_mode))
218		return -EINVAL;
219
220	ino = btrfs_ino(BTRFS_I(inode));
221
222	path = btrfs_alloc_path();
223	if (!path)
224		return -ENOMEM;
 
225
226	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
227		key.objectid = BTRFS_I(inode)->root->root_key.objectid;
228		key.type = BTRFS_ROOT_BACKREF_KEY;
229		key.offset = (u64)-1;
230		root = fs_info->tree_root;
231	} else {
232		key.objectid = ino;
233		key.offset = btrfs_ino(BTRFS_I(dir));
234		key.type = BTRFS_INODE_REF_KEY;
235	}
236
237	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
238	if (ret < 0) {
239		btrfs_free_path(path);
240		return ret;
241	} else if (ret > 0) {
242		if (ino == BTRFS_FIRST_FREE_OBJECTID) {
243			path->slots[0]--;
244		} else {
245			btrfs_free_path(path);
246			return -ENOENT;
247		}
248	}
249	leaf = path->nodes[0];
250
251	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
252		rref = btrfs_item_ptr(leaf, path->slots[0],
253				     struct btrfs_root_ref);
254		name_ptr = (unsigned long)(rref + 1);
255		name_len = btrfs_root_ref_name_len(leaf, rref);
256	} else {
257		iref = btrfs_item_ptr(leaf, path->slots[0],
258				      struct btrfs_inode_ref);
259		name_ptr = (unsigned long)(iref + 1);
260		name_len = btrfs_inode_ref_name_len(leaf, iref);
261	}
262
263	read_extent_buffer(leaf, name, name_ptr, name_len);
264	btrfs_free_path(path);
265
266	/*
267	 * have to add the null termination to make sure that reconnect_path
268	 * gets the right len for strlen
269	 */
270	name[name_len] = '\0';
271
272	return 0;
273}
274
275const struct export_operations btrfs_export_ops = {
276	.encode_fh	= btrfs_encode_fh,
277	.fh_to_dentry	= btrfs_fh_to_dentry,
278	.fh_to_parent	= btrfs_fh_to_parent,
279	.get_parent	= btrfs_get_parent,
280	.get_name	= btrfs_get_name,
281};