[linux.git] / fs / btrfs / export.c

// SPDX-License-Identifier: GPL-2.0

#include <linux/fs.h>
#include <linux/types.h>
#include "ctree.h"
#include "disk-io.h"
#include "btrfs_inode.h"
#include "print-tree.h"
#include "export.h"

#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
						 parent_objectid) / 4)
#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \
					     parent_root_objectid) / 4)
#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4)

static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
			   struct inode *parent)
{
	struct btrfs_fid *fid = (struct btrfs_fid *)fh;
	int len = *max_len;
	int type;

	if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
		*max_len = BTRFS_FID_SIZE_CONNECTABLE;
		return FILEID_INVALID;
	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
		*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
		return FILEID_INVALID;
	}

	len  = BTRFS_FID_SIZE_NON_CONNECTABLE;
	type = FILEID_BTRFS_WITHOUT_PARENT;

	fid->objectid = btrfs_ino(BTRFS_I(inode));
	fid->root_objectid = BTRFS_I(inode)->root->root_key.objectid;
	fid->gen = inode->i_generation;

	if (parent) {
		u64 parent_root_id;

		fid->parent_objectid = BTRFS_I(parent)->location.objectid;
		fid->parent_gen = parent->i_generation;
		parent_root_id = BTRFS_I(parent)->root->root_key.objectid;

		if (parent_root_id != fid->root_objectid) {
			fid->parent_root_objectid = parent_root_id;
			len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
			type = FILEID_BTRFS_WITH_PARENT_ROOT;
		} else {
			len = BTRFS_FID_SIZE_CONNECTABLE;
			type = FILEID_BTRFS_WITH_PARENT;
		}
	}

	*max_len = len;
	return type;
}

struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
				u64 root_objectid, u32 generation,
				int check_generation)
{
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	struct btrfs_root *root;
	struct inode *inode;

	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
		return ERR_PTR(-ESTALE);

	root = btrfs_get_fs_root(fs_info, root_objectid, true);
	if (IS_ERR(root))
		return ERR_CAST(root);

	inode = btrfs_iget(sb, objectid, root);
	btrfs_put_root(root);
	if (IS_ERR(inode))
		return ERR_CAST(inode);

	if (check_generation && generation != inode->i_generation) {
		iput(inode);
		return ERR_PTR(-ESTALE);
	}

	return d_obtain_alias(inode);
}

static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,
					 int fh_len, int fh_type)
{
	struct btrfs_fid *fid = (struct btrfs_fid *) fh;
	u64 objectid, root_objectid;
	u32 generation;

	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
		if (fh_len <  BTRFS_FID_SIZE_CONNECTABLE)
			return NULL;
		root_objectid = fid->root_objectid;
	} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
		if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
			return NULL;
		root_objectid = fid->parent_root_objectid;
	} else
		return NULL;

	objectid = fid->parent_objectid;
	generation = fid->parent_gen;

	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
}

static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
					 int fh_len, int fh_type)
{
	struct btrfs_fid *fid = (struct btrfs_fid *) fh;
	u64 objectid, root_objectid;
	u32 generation;

	if ((fh_type != FILEID_BTRFS_WITH_PARENT ||
	     fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
	    (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||
	     fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
	    (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||
	     fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
		return NULL;

	objectid = fid->objectid;
	root_objectid = fid->root_objectid;
	generation = fid->gen;

	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
}

struct dentry *btrfs_get_parent(struct dentry *child)
{
	struct inode *dir = d_inode(child);
	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
	struct btrfs_root *root = BTRFS_I(dir)->root;
	struct btrfs_path *path;
	struct extent_buffer *leaf;
	struct btrfs_root_ref *ref;
	struct btrfs_key key;
	struct btrfs_key found_key;
	int ret;

	path = btrfs_alloc_path();
	if (!path)
		return ERR_PTR(-ENOMEM);

	if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) {
		key.objectid = root->root_key.objectid;
		key.type = BTRFS_ROOT_BACKREF_KEY;
		key.offset = (u64)-1;
		root = fs_info->tree_root;
	} else {
		key.objectid = btrfs_ino(BTRFS_I(dir));
		key.type = BTRFS_INODE_REF_KEY;
		key.offset = (u64)-1;
	}

	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		goto fail;

	BUG_ON(ret == 0); /* Key with offset of -1 found */
	if (path->slots[0] == 0) {
		ret = -ENOENT;
		goto fail;
	}

	path->slots[0]--;
	leaf = path->nodes[0];

	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
	if (found_key.objectid != key.objectid || found_key.type != key.type) {
		ret = -ENOENT;
		goto fail;
	}

	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
		ref = btrfs_item_ptr(leaf, path->slots[0],
				     struct btrfs_root_ref);
		key.objectid = btrfs_root_ref_dirid(leaf, ref);
	} else {
		key.objectid = found_key.offset;
	}
	btrfs_free_path(path);

	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
		return btrfs_get_dentry(fs_info->sb, key.objectid,
					found_key.offset, 0, 0);
	}

	return d_obtain_alias(btrfs_iget(fs_info->sb, key.objectid, root));
fail:
	btrfs_free_path(path);
	return ERR_PTR(ret);
}

static int btrfs_get_name(struct dentry *parent, char *name,
			  struct dentry *child)
{
	struct inode *inode = d_inode(child);
	struct inode *dir = d_inode(parent);
	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
	struct btrfs_path *path;
	struct btrfs_root *root = BTRFS_I(dir)->root;
	struct btrfs_inode_ref *iref;
	struct btrfs_root_ref *rref;
	struct extent_buffer *leaf;
	unsigned long name_ptr;
	struct btrfs_key key;
	int name_len;
	int ret;
	u64 ino;

	if (!S_ISDIR(dir->i_mode))
		return -EINVAL;

	ino = btrfs_ino(BTRFS_I(inode));

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	path->leave_spinning = 1;

	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
		key.objectid = BTRFS_I(inode)->root->root_key.objectid;
		key.type = BTRFS_ROOT_BACKREF_KEY;
		key.offset = (u64)-1;
		root = fs_info->tree_root;
	} else {
		key.objectid = ino;
		key.offset = btrfs_ino(BTRFS_I(dir));
		key.type = BTRFS_INODE_REF_KEY;
	}

	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0) {
		btrfs_free_path(path);
		return ret;
	} else if (ret > 0) {
		if (ino == BTRFS_FIRST_FREE_OBJECTID) {
			path->slots[0]--;
		} else {
			btrfs_free_path(path);
			return -ENOENT;
		}
	}
	leaf = path->nodes[0];

	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
		rref = btrfs_item_ptr(leaf, path->slots[0],
				     struct btrfs_root_ref);
		name_ptr = (unsigned long)(rref + 1);
		name_len = btrfs_root_ref_name_len(leaf, rref);
	} else {
		iref = btrfs_item_ptr(leaf, path->slots[0],
				      struct btrfs_inode_ref);
		name_ptr = (unsigned long)(iref + 1);
		name_len = btrfs_inode_ref_name_len(leaf, iref);
	}

	read_extent_buffer(leaf, name, name_ptr, name_len);
	btrfs_free_path(path);

	/*
	 * have to add the null termination to make sure that reconnect_path
	 * gets the right len for strlen
	 */
	name[name_len] = '\0';

	return 0;
}

const struct export_operations btrfs_export_ops = {
	.encode_fh	= btrfs_encode_fh,
	.fh_to_dentry	= btrfs_fh_to_dentry,
	.fh_to_parent	= btrfs_fh_to_parent,
	.get_parent	= btrfs_get_parent,
	.get_name	= btrfs_get_name,
};
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
c1d7c514	2
be6e8dc0 BR	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"
be6e8dc0	10
d397712b CM	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)
be6e8dc0	16
b0b0382b AV	17	static int btrfs_encode_fh(struct inode inode, u32 fh, int *max_len,
b0b0382b AV	18	struct inode *parent)
be6e8dc0 BR	19	{
be6e8dc0 BR	20	struct btrfs_fid fid = (struct btrfs_fid )fh;
be6e8dc0 BR	21	int len = *max_len;
	22	int type;
	23
b0b0382b	24	if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
5fe0c237	25	*max_len = BTRFS_FID_SIZE_CONNECTABLE;
94e07a75	26	return FILEID_INVALID;
5fe0c237 AK	27	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
5fe0c237 AK	28	*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
94e07a75	29	return FILEID_INVALID;
5fe0c237	30	}
be6e8dc0 BR	31
	32	len = BTRFS_FID_SIZE_NON_CONNECTABLE;
	33	type = FILEID_BTRFS_WITHOUT_PARENT;
	34
4a0cc7ca	35	fid->objectid = btrfs_ino(BTRFS_I(inode));
4fd786e6	36	fid->root_objectid = BTRFS_I(inode)->root->root_key.objectid;
be6e8dc0 BR	37	fid->gen = inode->i_generation;
be6e8dc0 BR	38
b0b0382b	39	if (parent) {
be6e8dc0 BR	40	u64 parent_root_id;
be6e8dc0 BR	41
be6e8dc0 BR	42	fid->parent_objectid = BTRFS_I(parent)->location.objectid;
be6e8dc0 BR	43	fid->parent_gen = parent->i_generation;
4fd786e6	44	parent_root_id = BTRFS_I(parent)->root->root_key.objectid;
be6e8dc0	45
be6e8dc0 BR	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
c0c907a4 MPS	60	struct dentry btrfs_get_dentry(struct super_block sb, u64 objectid,
	61	u64 root_objectid, u32 generation,
	62	int check_generation)
be6e8dc0	63	{
815745cf	64	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
be6e8dc0 BR	65	struct btrfs_root *root;
be6e8dc0 BR	66	struct inode *inode;
76dda93c YZ	67
	68	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
	69	return ERR_PTR(-ESTALE);
be6e8dc0	70
56e9357a	71	root = btrfs_get_fs_root(fs_info, root_objectid, true);
c75e8394 JB	72	if (IS_ERR(root))
c75e8394 JB	73	return ERR_CAST(root);
76dda93c	74
0202e83f	75	inode = btrfs_iget(sb, objectid, root);
00246528	76	btrfs_put_root(root);
c75e8394 JB	77	if (IS_ERR(inode))
c75e8394 JB	78	return ERR_CAST(inode);
be6e8dc0	79
76dda93c	80	if (check_generation && generation != inode->i_generation) {
be6e8dc0 BR	81	iput(inode);
	82	return ERR_PTR(-ESTALE);
	83	}
	84
af53d29a	85	return d_obtain_alias(inode);
be6e8dc0 BR	86	}
	87
	88	static 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) {
7d35199e	96	if (fh_len < BTRFS_FID_SIZE_CONNECTABLE)
be6e8dc0 BR	97	return NULL;
	98	root_objectid = fid->root_objectid;
	99	} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
7d35199e	100	if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)
be6e8dc0 BR	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
76dda93c	109	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
be6e8dc0 BR	110	}
	111
	112	static 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 \|\|
7d35199e	120	fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&
be6e8dc0	121	(fh_type != FILEID_BTRFS_WITH_PARENT_ROOT \|\|
7d35199e	122	fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
be6e8dc0	123	(fh_type != FILEID_BTRFS_WITHOUT_PARENT \|\|
7d35199e	124	fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))
be6e8dc0 BR	125	return NULL;
	126
	127	objectid = fid->objectid;
	128	root_objectid = fid->root_objectid;
	129	generation = fid->gen;
	130
76dda93c	131	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
be6e8dc0 BR	132	}
be6e8dc0 BR	133
c0c907a4	134	struct dentry btrfs_get_parent(struct dentry child)
be6e8dc0	135	{
2b0143b5	136	struct inode *dir = d_inode(child);
0b246afa	137	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
be6e8dc0	138	struct btrfs_root *root = BTRFS_I(dir)->root;
be6e8dc0 BR	139	struct btrfs_path *path;
be6e8dc0 BR	140	struct extent_buffer *leaf;
76dda93c YZ	141	struct btrfs_root_ref *ref;
	142	struct btrfs_key key;
	143	struct btrfs_key found_key;
be6e8dc0 BR	144	int ret;
	145
	146	path = btrfs_alloc_path();
2a29edc6	147	if (!path)
2a29edc6	148	return ERR_PTR(-ENOMEM);
be6e8dc0	149
4a0cc7ca	150	if (btrfs_ino(BTRFS_I(dir)) == BTRFS_FIRST_FREE_OBJECTID) {
76dda93c YZ	151	key.objectid = root->root_key.objectid;
	152	key.type = BTRFS_ROOT_BACKREF_KEY;
	153	key.offset = (u64)-1;
0b246afa	154	root = fs_info->tree_root;
76dda93c	155	} else {
4a0cc7ca	156	key.objectid = btrfs_ino(BTRFS_I(dir));
76dda93c YZ	157	key.type = BTRFS_INODE_REF_KEY;
	158	key.offset = (u64)-1;
	159	}
be6e8dc0	160
87acb4ef	161	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
76dda93c YZ	162	if (ret < 0)
	163	goto fail;
	164
79787eaa	165	BUG_ON(ret == 0); /* Key with offset of -1 found */
76dda93c YZ	166	if (path->slots[0] == 0) {
	167	ret = -ENOENT;
	168	goto fail;
d54a8390	169	}
76dda93c YZ	170
76dda93c YZ	171	path->slots[0]--;
be6e8dc0	172	leaf = path->nodes[0];
76dda93c YZ	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;
be6e8dc0 BR	178	}
be6e8dc0 BR	179
76dda93c YZ	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	}
be6e8dc0 BR	187	btrfs_free_path(path);
be6e8dc0 BR	188
76dda93c	189	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
0b246afa	190	return btrfs_get_dentry(fs_info->sb, key.objectid,
76dda93c YZ	191	found_key.offset, 0, 0);
76dda93c YZ	192	}
2d4d9fbd	193
0202e83f	194	return d_obtain_alias(btrfs_iget(fs_info->sb, key.objectid, root));
76dda93c YZ	195	fail:
	196	btrfs_free_path(path);
	197	return ERR_PTR(ret);
be6e8dc0 BR	198	}
be6e8dc0 BR	199
2ede0daf JB	200	static int btrfs_get_name(struct dentry parent, char name,
	201	struct dentry *child)
	202	{
2b0143b5 DH	203	struct inode *inode = d_inode(child);
2b0143b5 DH	204	struct inode *dir = d_inode(parent);
0b246afa	205	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2ede0daf JB	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;
33345d01	215	u64 ino;
2ede0daf	216
2ede0daf JB	217	if (!S_ISDIR(dir->i_mode))
	218	return -EINVAL;
	219
4a0cc7ca	220	ino = btrfs_ino(BTRFS_I(inode));
33345d01	221
2ede0daf JB	222	path = btrfs_alloc_path();
	223	if (!path)
	224	return -ENOMEM;
	225	path->leave_spinning = 1;
	226
33345d01	227	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
2ede0daf JB	228	key.objectid = BTRFS_I(inode)->root->root_key.objectid;
	229	key.type = BTRFS_ROOT_BACKREF_KEY;
	230	key.offset = (u64)-1;
0b246afa	231	root = fs_info->tree_root;
2ede0daf	232	} else {
33345d01	233	key.objectid = ino;
4a0cc7ca	234	key.offset = btrfs_ino(BTRFS_I(dir));
2ede0daf JB	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) {
33345d01	243	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
2ede0daf JB	244	path->slots[0]--;
	245	} else {
	246	btrfs_free_path(path);
	247	return -ENOENT;
	248	}
	249	}
	250	leaf = path->nodes[0];
	251
33345d01 LZ	252	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
33345d01 LZ	253	rref = btrfs_item_ptr(leaf, path->slots[0],
2ede0daf	254	struct btrfs_root_ref);
33345d01 LZ	255	name_ptr = (unsigned long)(rref + 1);
33345d01 LZ	256	name_len = btrfs_root_ref_name_len(leaf, rref);
2ede0daf JB	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
be6e8dc0 BR	276	const 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,
2ede0daf	281	.get_name = btrfs_get_name,
be6e8dc0	282	};