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

#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"
#include "compat.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(inode);
	fid->root_objectid = BTRFS_I(inode)->root->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->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;
}

static 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;
	struct btrfs_key key;
	int index;
	int err = 0;

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

	key.objectid = root_objectid;
	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
	key.offset = (u64)-1;

	index = srcu_read_lock(&fs_info->subvol_srcu);

	root = btrfs_read_fs_root_no_name(fs_info, &key);
	if (IS_ERR(root)) {
		err = PTR_ERR(root);
		goto fail;
	}

	key.objectid = objectid;
	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
	key.offset = 0;

	inode = btrfs_iget(sb, &key, root, NULL);
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto fail;
	}

	srcu_read_unlock(&fs_info->subvol_srcu, index);

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

	return d_obtain_alias(inode);
fail:
	srcu_read_unlock(&fs_info->subvol_srcu, index);
	return ERR_PTR(err);
}

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);
}

static struct dentry *btrfs_get_parent(struct dentry *child)
{
	struct inode *dir = child->d_inode;
	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(dir) == BTRFS_FIRST_FREE_OBJECTID) {
		key.objectid = root->root_key.objectid;
		key.type = BTRFS_ROOT_BACKREF_KEY;
		key.offset = (u64)-1;
		root = root->fs_info->tree_root;
	} else {
		key.objectid = btrfs_ino(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(root->fs_info->sb, key.objectid,
					found_key.offset, 0, 0);
	}

	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;
	return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
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 = child->d_inode;
	struct inode *dir = parent->d_inode;
	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 (!dir || !inode)
		return -EINVAL;

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

	ino = btrfs_ino(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 = root->fs_info->tree_root;
	} else {
		key.objectid = ino;
		key.offset = btrfs_ino(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
be6e8dc0 BR	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
d397712b CM	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)
be6e8dc0	15
b0b0382b AV	16	static int btrfs_encode_fh(struct inode inode, u32 fh, int *max_len,
b0b0382b AV	17	struct inode *parent)
be6e8dc0 BR	18	{
be6e8dc0 BR	19	struct btrfs_fid fid = (struct btrfs_fid )fh;
be6e8dc0 BR	20	int len = *max_len;
	21	int type;
	22
b0b0382b	23	if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
5fe0c237	24	*max_len = BTRFS_FID_SIZE_CONNECTABLE;
94e07a75	25	return FILEID_INVALID;
5fe0c237 AK	26	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
5fe0c237 AK	27	*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
94e07a75	28	return FILEID_INVALID;
5fe0c237	29	}
be6e8dc0 BR	30
	31	len = BTRFS_FID_SIZE_NON_CONNECTABLE;
	32	type = FILEID_BTRFS_WITHOUT_PARENT;
	33
33345d01	34	fid->objectid = btrfs_ino(inode);
be6e8dc0 BR	35	fid->root_objectid = BTRFS_I(inode)->root->objectid;
	36	fid->gen = inode->i_generation;
	37
b0b0382b	38	if (parent) {
be6e8dc0 BR	39	u64 parent_root_id;
be6e8dc0 BR	40
be6e8dc0 BR	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
be6e8dc0 BR	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
	59	static struct dentry btrfs_get_dentry(struct super_block sb, u64 objectid,
76dda93c YZ	60	u64 root_objectid, u32 generation,
76dda93c YZ	61	int check_generation)
be6e8dc0	62	{
815745cf	63	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
be6e8dc0 BR	64	struct btrfs_root *root;
be6e8dc0 BR	65	struct inode *inode;
be6e8dc0	66	struct btrfs_key key;
76dda93c YZ	67	int index;
	68	int err = 0;
	69
	70	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
	71	return ERR_PTR(-ESTALE);
be6e8dc0	72
2d4d9fbd DW	73	key.objectid = root_objectid;
	74	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
	75	key.offset = (u64)-1;
	76
76dda93c YZ	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
be6e8dc0 BR	85	key.objectid = objectid;
	86	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
	87	key.offset = 0;
	88
73f73415	89	inode = btrfs_iget(sb, &key, root, NULL);
76dda93c YZ	90	if (IS_ERR(inode)) {
	91	err = PTR_ERR(inode);
	92	goto fail;
	93	}
	94
	95	srcu_read_unlock(&fs_info->subvol_srcu, index);
be6e8dc0	96
76dda93c	97	if (check_generation && generation != inode->i_generation) {
be6e8dc0 BR	98	iput(inode);
	99	return ERR_PTR(-ESTALE);
	100	}
	101
af53d29a	102	return d_obtain_alias(inode);
76dda93c YZ	103	fail:
	104	srcu_read_unlock(&fs_info->subvol_srcu, index);
	105	return ERR_PTR(err);
be6e8dc0 BR	106	}
	107
	108	static struct dentry btrfs_fh_to_parent(struct super_block sb, struct fid *fh,
	109	int fh_len, int fh_type)
	110	{
	111	struct btrfs_fid fid = (struct btrfs_fid ) fh;
	112	u64 objectid, root_objectid;
	113	u32 generation;
	114
	115	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
	116	if (fh_len != BTRFS_FID_SIZE_CONNECTABLE)
	117	return NULL;
	118	root_objectid = fid->root_objectid;
	119	} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
	120	if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
	121	return NULL;
	122	root_objectid = fid->parent_root_objectid;
	123	} else
	124	return NULL;
	125
	126	objectid = fid->parent_objectid;
	127	generation = fid->parent_gen;
	128
76dda93c	129	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
be6e8dc0 BR	130	}
	131
	132	static struct dentry btrfs_fh_to_dentry(struct super_block sb, struct fid *fh,
	133	int fh_len, int fh_type)
	134	{
	135	struct btrfs_fid fid = (struct btrfs_fid ) fh;
	136	u64 objectid, root_objectid;
	137	u32 generation;
	138
	139	if ((fh_type != FILEID_BTRFS_WITH_PARENT \|\|
	140	fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
	141	(fh_type != FILEID_BTRFS_WITH_PARENT_ROOT \|\|
	142	fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
	143	(fh_type != FILEID_BTRFS_WITHOUT_PARENT \|\|
	144	fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
	145	return NULL;
	146
	147	objectid = fid->objectid;
	148	root_objectid = fid->root_objectid;
	149	generation = fid->gen;
	150
76dda93c	151	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
be6e8dc0 BR	152	}
	153
	154	static struct dentry btrfs_get_parent(struct dentry child)
	155	{
	156	struct inode *dir = child->d_inode;
be6e8dc0	157	struct btrfs_root *root = BTRFS_I(dir)->root;
be6e8dc0 BR	158	struct btrfs_path *path;
be6e8dc0 BR	159	struct extent_buffer *leaf;
76dda93c YZ	160	struct btrfs_root_ref *ref;
	161	struct btrfs_key key;
	162	struct btrfs_key found_key;
be6e8dc0 BR	163	int ret;
	164
	165	path = btrfs_alloc_path();
2a29edc6	166	if (!path)
2a29edc6	167	return ERR_PTR(-ENOMEM);
be6e8dc0	168
33345d01	169	if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
76dda93c YZ	170	key.objectid = root->root_key.objectid;
	171	key.type = BTRFS_ROOT_BACKREF_KEY;
	172	key.offset = (u64)-1;
	173	root = root->fs_info->tree_root;
	174	} else {
33345d01	175	key.objectid = btrfs_ino(dir);
76dda93c YZ	176	key.type = BTRFS_INODE_REF_KEY;
	177	key.offset = (u64)-1;
	178	}
be6e8dc0	179
87acb4ef	180	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
76dda93c YZ	181	if (ret < 0)
	182	goto fail;
	183
79787eaa	184	BUG_ON(ret == 0); /* Key with offset of -1 found */
76dda93c YZ	185	if (path->slots[0] == 0) {
	186	ret = -ENOENT;
	187	goto fail;
d54a8390	188	}
76dda93c YZ	189
76dda93c YZ	190	path->slots[0]--;
be6e8dc0	191	leaf = path->nodes[0];
76dda93c YZ	192
	193	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
	194	if (found_key.objectid != key.objectid \|\| found_key.type != key.type) {
	195	ret = -ENOENT;
	196	goto fail;
be6e8dc0 BR	197	}
be6e8dc0 BR	198
76dda93c YZ	199	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
	200	ref = btrfs_item_ptr(leaf, path->slots[0],
	201	struct btrfs_root_ref);
	202	key.objectid = btrfs_root_ref_dirid(leaf, ref);
	203	} else {
	204	key.objectid = found_key.offset;
	205	}
be6e8dc0 BR	206	btrfs_free_path(path);
be6e8dc0 BR	207
76dda93c YZ	208	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
	209	return btrfs_get_dentry(root->fs_info->sb, key.objectid,
	210	found_key.offset, 0, 0);
	211	}
2d4d9fbd	212
76dda93c	213	key.type = BTRFS_INODE_ITEM_KEY;
be6e8dc0	214	key.offset = 0;
af53d29a	215	return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
76dda93c YZ	216	fail:
	217	btrfs_free_path(path);
	218	return ERR_PTR(ret);
be6e8dc0 BR	219	}
be6e8dc0 BR	220
2ede0daf JB	221	static int btrfs_get_name(struct dentry parent, char name,
	222	struct dentry *child)
	223	{
	224	struct inode *inode = child->d_inode;
	225	struct inode *dir = parent->d_inode;
	226	struct btrfs_path *path;
	227	struct btrfs_root *root = BTRFS_I(dir)->root;
	228	struct btrfs_inode_ref *iref;
	229	struct btrfs_root_ref *rref;
	230	struct extent_buffer *leaf;
	231	unsigned long name_ptr;
	232	struct btrfs_key key;
	233	int name_len;
	234	int ret;
33345d01	235	u64 ino;
2ede0daf JB	236
	237	if (!dir \|\| !inode)
	238	return -EINVAL;
	239
	240	if (!S_ISDIR(dir->i_mode))
	241	return -EINVAL;
	242
33345d01 LZ	243	ino = btrfs_ino(inode);
33345d01 LZ	244
2ede0daf JB	245	path = btrfs_alloc_path();
	246	if (!path)
	247	return -ENOMEM;
	248	path->leave_spinning = 1;
	249
33345d01	250	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
2ede0daf JB	251	key.objectid = BTRFS_I(inode)->root->root_key.objectid;
	252	key.type = BTRFS_ROOT_BACKREF_KEY;
	253	key.offset = (u64)-1;
	254	root = root->fs_info->tree_root;
	255	} else {
33345d01 LZ	256	key.objectid = ino;
33345d01 LZ	257	key.offset = btrfs_ino(dir);
2ede0daf JB	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) {
33345d01	266	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
2ede0daf JB	267	path->slots[0]--;
	268	} else {
	269	btrfs_free_path(path);
	270	return -ENOENT;
	271	}
	272	}
	273	leaf = path->nodes[0];
	274
33345d01 LZ	275	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
33345d01 LZ	276	rref = btrfs_item_ptr(leaf, path->slots[0],
2ede0daf	277	struct btrfs_root_ref);
33345d01 LZ	278	name_ptr = (unsigned long)(rref + 1);
33345d01 LZ	279	name_len = btrfs_root_ref_name_len(leaf, rref);
2ede0daf JB	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
be6e8dc0 BR	299	const 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,
2ede0daf	304	.get_name = btrfs_get_name,
be6e8dc0	305	};