[mirror_ubuntu-bionic-kernel.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 255;
	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
		*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
		return 255;
	}

	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;
	}

	if (btrfs_root_refs(&root->root_item) == 0) {
		err = -ENOENT;
		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;
be6e8dc0	25	return 255;
5fe0c237 AK	26	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
	27	*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
	28	return 255;
	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
	85	if (btrfs_root_refs(&root->root_item) == 0) {
	86	err = -ENOENT;
	87	goto fail;
	88	}
2d4d9fbd	89
be6e8dc0 BR	90	key.objectid = objectid;
	91	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
	92	key.offset = 0;
	93
73f73415	94	inode = btrfs_iget(sb, &key, root, NULL);
76dda93c YZ	95	if (IS_ERR(inode)) {
	96	err = PTR_ERR(inode);
	97	goto fail;
	98	}
	99
	100	srcu_read_unlock(&fs_info->subvol_srcu, index);
be6e8dc0	101
76dda93c	102	if (check_generation && generation != inode->i_generation) {
be6e8dc0 BR	103	iput(inode);
	104	return ERR_PTR(-ESTALE);
	105	}
	106
af53d29a	107	return d_obtain_alias(inode);
76dda93c YZ	108	fail:
	109	srcu_read_unlock(&fs_info->subvol_srcu, index);
	110	return ERR_PTR(err);
be6e8dc0 BR	111	}
	112
	113	static 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
76dda93c	134	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
be6e8dc0 BR	135	}
	136
	137	static 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
76dda93c	156	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
be6e8dc0 BR	157	}
	158
	159	static struct dentry btrfs_get_parent(struct dentry child)
	160	{
	161	struct inode *dir = child->d_inode;
be6e8dc0	162	struct btrfs_root *root = BTRFS_I(dir)->root;
be6e8dc0 BR	163	struct btrfs_path *path;
be6e8dc0 BR	164	struct extent_buffer *leaf;
76dda93c YZ	165	struct btrfs_root_ref *ref;
	166	struct btrfs_key key;
	167	struct btrfs_key found_key;
be6e8dc0 BR	168	int ret;
	169
	170	path = btrfs_alloc_path();
2a29edc6	171	if (!path)
2a29edc6	172	return ERR_PTR(-ENOMEM);
be6e8dc0	173
33345d01	174	if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
76dda93c YZ	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 {
33345d01	180	key.objectid = btrfs_ino(dir);
76dda93c YZ	181	key.type = BTRFS_INODE_REF_KEY;
	182	key.offset = (u64)-1;
	183	}
be6e8dc0	184
87acb4ef	185	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
76dda93c YZ	186	if (ret < 0)
	187	goto fail;
	188
79787eaa	189	BUG_ON(ret == 0); /* Key with offset of -1 found */
76dda93c YZ	190	if (path->slots[0] == 0) {
	191	ret = -ENOENT;
	192	goto fail;
d54a8390	193	}
76dda93c YZ	194
76dda93c YZ	195	path->slots[0]--;
be6e8dc0	196	leaf = path->nodes[0];
76dda93c YZ	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;
be6e8dc0 BR	202	}
be6e8dc0 BR	203
76dda93c YZ	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	}
be6e8dc0 BR	211	btrfs_free_path(path);
be6e8dc0 BR	212
76dda93c YZ	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	}
2d4d9fbd	217
76dda93c	218	key.type = BTRFS_INODE_ITEM_KEY;
be6e8dc0	219	key.offset = 0;
af53d29a	220	return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
76dda93c YZ	221	fail:
	222	btrfs_free_path(path);
	223	return ERR_PTR(ret);
be6e8dc0 BR	224	}
be6e8dc0 BR	225
2ede0daf JB	226	static 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;
33345d01	240	u64 ino;
2ede0daf JB	241
	242	if (!dir \|\| !inode)
	243	return -EINVAL;
	244
	245	if (!S_ISDIR(dir->i_mode))
	246	return -EINVAL;
	247
33345d01 LZ	248	ino = btrfs_ino(inode);
33345d01 LZ	249
2ede0daf JB	250	path = btrfs_alloc_path();
	251	if (!path)
	252	return -ENOMEM;
	253	path->leave_spinning = 1;
	254
33345d01	255	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
2ede0daf JB	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 {
33345d01 LZ	261	key.objectid = ino;
33345d01 LZ	262	key.offset = btrfs_ino(dir);
2ede0daf JB	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) {
33345d01	271	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
2ede0daf JB	272	path->slots[0]--;
	273	} else {
	274	btrfs_free_path(path);
	275	return -ENOENT;
	276	}
	277	}
	278	leaf = path->nodes[0];
	279
33345d01 LZ	280	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
33345d01 LZ	281	rref = btrfs_item_ptr(leaf, path->slots[0],
2ede0daf	282	struct btrfs_root_ref);
33345d01 LZ	283	name_ptr = (unsigned long)(rref + 1);
33345d01 LZ	284	name_len = btrfs_root_ref_name_len(leaf, rref);
2ede0daf JB	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
be6e8dc0 BR	304	const 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,
2ede0daf	309	.get_name = btrfs_get_name,
be6e8dc0	310	};