[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 dentry *dentry, u32 *fh, int *max_len,
			   int connectable)
{
	struct btrfs_fid *fid = (struct btrfs_fid *)fh;
	struct inode *inode = dentry->d_inode;
	int len = *max_len;
	int type;

	if (connectable && (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 = inode->i_ino;
	fid->root_objectid = BTRFS_I(inode)->root->objectid;
	fid->gen = inode->i_generation;

	if (connectable && !S_ISDIR(inode->i_mode)) {
		struct inode *parent;
		u64 parent_root_id;

		spin_lock(&dentry->d_lock);

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

		spin_unlock(&dentry->d_lock);

		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)->fs_info;
	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 (dir->i_ino == 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 = dir->i_ino;
		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);
	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;

	if (!dir || !inode)
		return -EINVAL;

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

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

	if (inode->i_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 = inode->i_ino;
		key.offset = dir->i_ino;
		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 (inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
			path->slots[0]--;
		} else {
			btrfs_free_path(path);
			return -ENOENT;
		}
	}
	leaf = path->nodes[0];

	if (inode->i_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 BR	15
	16	static 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
5fe0c237 AK	24	if (connectable && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
5fe0c237 AK	25	*max_len = BTRFS_FID_SIZE_CONNECTABLE;
be6e8dc0	26	return 255;
5fe0c237 AK	27	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
	28	*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
	29	return 255;
	30	}
be6e8dc0 BR	31
	32	len = BTRFS_FID_SIZE_NON_CONNECTABLE;
	33	type = FILEID_BTRFS_WITHOUT_PARENT;
	34
76dda93c	35	fid->objectid = inode->i_ino;
be6e8dc0 BR	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
	66	static struct dentry btrfs_get_dentry(struct super_block sb, u64 objectid,
76dda93c YZ	67	u64 root_objectid, u32 generation,
76dda93c YZ	68	int check_generation)
be6e8dc0	69	{
76dda93c	70	struct btrfs_fs_info *fs_info = btrfs_sb(sb)->fs_info;
be6e8dc0 BR	71	struct btrfs_root *root;
be6e8dc0 BR	72	struct inode *inode;
be6e8dc0	73	struct btrfs_key key;
76dda93c YZ	74	int index;
	75	int err = 0;
	76
	77	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
	78	return ERR_PTR(-ESTALE);
be6e8dc0	79
2d4d9fbd DW	80	key.objectid = root_objectid;
	81	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
	82	key.offset = (u64)-1;
	83
76dda93c YZ	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	}
2d4d9fbd	96
be6e8dc0 BR	97	key.objectid = objectid;
	98	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
	99	key.offset = 0;
	100
73f73415	101	inode = btrfs_iget(sb, &key, root, NULL);
76dda93c YZ	102	if (IS_ERR(inode)) {
	103	err = PTR_ERR(inode);
	104	goto fail;
	105	}
	106
	107	srcu_read_unlock(&fs_info->subvol_srcu, index);
be6e8dc0	108
76dda93c	109	if (check_generation && generation != inode->i_generation) {
be6e8dc0 BR	110	iput(inode);
	111	return ERR_PTR(-ESTALE);
	112	}
	113
af53d29a	114	return d_obtain_alias(inode);
76dda93c YZ	115	fail:
	116	srcu_read_unlock(&fs_info->subvol_srcu, index);
	117	return ERR_PTR(err);
be6e8dc0 BR	118	}
	119
	120	static 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
76dda93c	141	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
be6e8dc0 BR	142	}
	143
	144	static 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
76dda93c	163	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
be6e8dc0 BR	164	}
	165
	166	static struct dentry btrfs_get_parent(struct dentry child)
	167	{
	168	struct inode *dir = child->d_inode;
be6e8dc0	169	struct btrfs_root *root = BTRFS_I(dir)->root;
be6e8dc0 BR	170	struct btrfs_path *path;
be6e8dc0 BR	171	struct extent_buffer *leaf;
76dda93c YZ	172	struct btrfs_root_ref *ref;
	173	struct btrfs_key key;
	174	struct btrfs_key found_key;
be6e8dc0 BR	175	int ret;
	176
	177	path = btrfs_alloc_path();
2a29edc6	178	if (!path)
2a29edc6	179	return ERR_PTR(-ENOMEM);
be6e8dc0	180
76dda93c YZ	181	if (dir->i_ino == 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 = dir->i_ino;
	188	key.type = BTRFS_INODE_REF_KEY;
	189	key.offset = (u64)-1;
	190	}
be6e8dc0	191
87acb4ef	192	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
76dda93c YZ	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;
d54a8390	200	}
76dda93c YZ	201
76dda93c YZ	202	path->slots[0]--;
be6e8dc0	203	leaf = path->nodes[0];
76dda93c YZ	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;
be6e8dc0 BR	209	}
be6e8dc0 BR	210
76dda93c YZ	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	}
be6e8dc0 BR	218	btrfs_free_path(path);
be6e8dc0 BR	219
76dda93c YZ	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	}
2d4d9fbd	224
76dda93c	225	key.type = BTRFS_INODE_ITEM_KEY;
be6e8dc0	226	key.offset = 0;
af53d29a	227	return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
76dda93c YZ	228	fail:
	229	btrfs_free_path(path);
	230	return ERR_PTR(ret);
be6e8dc0 BR	231	}
be6e8dc0 BR	232
2ede0daf JB	233	static 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
	248	if (!dir \|\| !inode)
	249	return -EINVAL;
	250
	251	if (!S_ISDIR(dir->i_mode))
	252	return -EINVAL;
	253
	254	path = btrfs_alloc_path();
	255	if (!path)
	256	return -ENOMEM;
	257	path->leave_spinning = 1;
	258
	259	if (inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
	260	key.objectid = BTRFS_I(inode)->root->root_key.objectid;
	261	key.type = BTRFS_ROOT_BACKREF_KEY;
	262	key.offset = (u64)-1;
	263	root = root->fs_info->tree_root;
	264	} else {
	265	key.objectid = inode->i_ino;
	266	key.offset = dir->i_ino;
	267	key.type = BTRFS_INODE_REF_KEY;
	268	}
	269
	270	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	271	if (ret < 0) {
	272	btrfs_free_path(path);
	273	return ret;
	274	} else if (ret > 0) {
	275	if (inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
	276	path->slots[0]--;
	277	} else {
	278	btrfs_free_path(path);
	279	return -ENOENT;
	280	}
	281	}
	282	leaf = path->nodes[0];
	283
	284	if (inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
	285	rref = btrfs_item_ptr(leaf, path->slots[0],
	286	struct btrfs_root_ref);
	287	name_ptr = (unsigned long)(rref + 1);
	288	name_len = btrfs_root_ref_name_len(leaf, rref);
	289	} else {
	290	iref = btrfs_item_ptr(leaf, path->slots[0],
	291	struct btrfs_inode_ref);
	292	name_ptr = (unsigned long)(iref + 1);
	293	name_len = btrfs_inode_ref_name_len(leaf, iref);
	294	}
	295
	296	read_extent_buffer(leaf, name, name_ptr, name_len);
297	btrfs_free_path(path);
298
299	/*
300	* have to add the null termination to make sure that reconnect_path
301	* gets the right len for strlen
302	*/
303	name[name_len] = '\0';
304
305	return 0;
306	}
307
be6e8dc0 BR	308	const struct export_operations btrfs_export_ops = {
	309	.encode_fh = btrfs_encode_fh,
	310	.fh_to_dentry = btrfs_fh_to_dentry,
	311	.fh_to_parent = btrfs_fh_to_parent,
	312	.get_parent = btrfs_get_parent,
2ede0daf	313	.get_name = btrfs_get_name,
be6e8dc0	314	};