[GitHub/mt8127/android_kernel_alcatel_ttab.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 ((len < BTRFS_FID_SIZE_NON_CONNECTABLE) ||
	    (connectable && len < BTRFS_FID_SIZE_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 (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 (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);
	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 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
	24	if ((len < BTRFS_FID_SIZE_NON_CONNECTABLE) \|\|
	25	(connectable && len < BTRFS_FID_SIZE_CONNECTABLE))
	26	return 255;
	27
	28	len = BTRFS_FID_SIZE_NON_CONNECTABLE;
	29	type = FILEID_BTRFS_WITHOUT_PARENT;
	30
33345d01	31	fid->objectid = btrfs_ino(inode);
be6e8dc0 BR	32	fid->root_objectid = BTRFS_I(inode)->root->objectid;
	33	fid->gen = inode->i_generation;
	34
	35	if (connectable && !S_ISDIR(inode->i_mode)) {
	36	struct inode *parent;
	37	u64 parent_root_id;
	38
	39	spin_lock(&dentry->d_lock);
	40
	41	parent = dentry->d_parent->d_inode;
	42	fid->parent_objectid = BTRFS_I(parent)->location.objectid;
	43	fid->parent_gen = parent->i_generation;
	44	parent_root_id = BTRFS_I(parent)->root->objectid;
	45
	46	spin_unlock(&dentry->d_lock);
	47
	48	if (parent_root_id != fid->root_objectid) {
	49	fid->parent_root_objectid = parent_root_id;
	50	len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;
	51	type = FILEID_BTRFS_WITH_PARENT_ROOT;
	52	} else {
	53	len = BTRFS_FID_SIZE_CONNECTABLE;
	54	type = FILEID_BTRFS_WITH_PARENT;
	55	}
	56	}
	57
	58	*max_len = len;
	59	return type;
	60	}
	61
	62	static struct dentry btrfs_get_dentry(struct super_block sb, u64 objectid,
76dda93c YZ	63	u64 root_objectid, u32 generation,
76dda93c YZ	64	int check_generation)
be6e8dc0	65	{
76dda93c	66	struct btrfs_fs_info *fs_info = btrfs_sb(sb)->fs_info;
be6e8dc0 BR	67	struct btrfs_root *root;
be6e8dc0 BR	68	struct inode *inode;
be6e8dc0	69	struct btrfs_key key;
76dda93c YZ	70	int index;
	71	int err = 0;
	72
	73	if (objectid < BTRFS_FIRST_FREE_OBJECTID)
	74	return ERR_PTR(-ESTALE);
be6e8dc0	75
2d4d9fbd DW	76	key.objectid = root_objectid;
	77	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
	78	key.offset = (u64)-1;
	79
76dda93c YZ	80	index = srcu_read_lock(&fs_info->subvol_srcu);
	81
	82	root = btrfs_read_fs_root_no_name(fs_info, &key);
	83	if (IS_ERR(root)) {
	84	err = PTR_ERR(root);
	85	goto fail;
	86	}
	87
	88	if (btrfs_root_refs(&root->root_item) == 0) {
	89	err = -ENOENT;
	90	goto fail;
	91	}
2d4d9fbd	92
be6e8dc0 BR	93	key.objectid = objectid;
	94	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
	95	key.offset = 0;
	96
73f73415	97	inode = btrfs_iget(sb, &key, root, NULL);
76dda93c YZ	98	if (IS_ERR(inode)) {
	99	err = PTR_ERR(inode);
	100	goto fail;
	101	}
	102
	103	srcu_read_unlock(&fs_info->subvol_srcu, index);
be6e8dc0	104
76dda93c	105	if (check_generation && generation != inode->i_generation) {
be6e8dc0 BR	106	iput(inode);
	107	return ERR_PTR(-ESTALE);
	108	}
	109
af53d29a	110	return d_obtain_alias(inode);
76dda93c YZ	111	fail:
	112	srcu_read_unlock(&fs_info->subvol_srcu, index);
	113	return ERR_PTR(err);
be6e8dc0 BR	114	}
	115
	116	static struct dentry btrfs_fh_to_parent(struct super_block sb, struct fid *fh,
	117	int fh_len, int fh_type)
	118	{
	119	struct btrfs_fid fid = (struct btrfs_fid ) fh;
	120	u64 objectid, root_objectid;
	121	u32 generation;
	122
	123	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
	124	if (fh_len != BTRFS_FID_SIZE_CONNECTABLE)
	125	return NULL;
	126	root_objectid = fid->root_objectid;
	127	} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {
	128	if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)
	129	return NULL;
	130	root_objectid = fid->parent_root_objectid;
	131	} else
	132	return NULL;
	133
	134	objectid = fid->parent_objectid;
	135	generation = fid->parent_gen;
	136
76dda93c	137	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
be6e8dc0 BR	138	}
	139
	140	static struct dentry btrfs_fh_to_dentry(struct super_block sb, struct fid *fh,
	141	int fh_len, int fh_type)
	142	{
	143	struct btrfs_fid fid = (struct btrfs_fid ) fh;
	144	u64 objectid, root_objectid;
	145	u32 generation;
	146
	147	if ((fh_type != FILEID_BTRFS_WITH_PARENT \|\|
	148	fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&
	149	(fh_type != FILEID_BTRFS_WITH_PARENT_ROOT \|\|
	150	fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&
	151	(fh_type != FILEID_BTRFS_WITHOUT_PARENT \|\|
	152	fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))
	153	return NULL;
	154
	155	objectid = fid->objectid;
	156	root_objectid = fid->root_objectid;
	157	generation = fid->gen;
	158
76dda93c	159	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);
be6e8dc0 BR	160	}
	161
	162	static struct dentry btrfs_get_parent(struct dentry child)
	163	{
	164	struct inode *dir = child->d_inode;
be6e8dc0	165	struct btrfs_root *root = BTRFS_I(dir)->root;
be6e8dc0 BR	166	struct btrfs_path *path;
be6e8dc0 BR	167	struct extent_buffer *leaf;
76dda93c YZ	168	struct btrfs_root_ref *ref;
	169	struct btrfs_key key;
	170	struct btrfs_key found_key;
be6e8dc0 BR	171	int ret;
	172
	173	path = btrfs_alloc_path();
2a29edc6	174	if (!path)
2a29edc6	175	return ERR_PTR(-ENOMEM);
be6e8dc0	176
33345d01	177	if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {
76dda93c YZ	178	key.objectid = root->root_key.objectid;
	179	key.type = BTRFS_ROOT_BACKREF_KEY;
	180	key.offset = (u64)-1;
	181	root = root->fs_info->tree_root;
	182	} else {
33345d01	183	key.objectid = btrfs_ino(dir);
76dda93c YZ	184	key.type = BTRFS_INODE_REF_KEY;
	185	key.offset = (u64)-1;
	186	}
be6e8dc0	187
87acb4ef	188	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
76dda93c YZ	189	if (ret < 0)
	190	goto fail;
	191
	192	BUG_ON(ret == 0);
	193	if (path->slots[0] == 0) {
	194	ret = -ENOENT;
	195	goto fail;
d54a8390	196	}
76dda93c YZ	197
76dda93c YZ	198	path->slots[0]--;
be6e8dc0	199	leaf = path->nodes[0];
76dda93c YZ	200
	201	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
	202	if (found_key.objectid != key.objectid \|\| found_key.type != key.type) {
	203	ret = -ENOENT;
	204	goto fail;
be6e8dc0 BR	205	}
be6e8dc0 BR	206
76dda93c YZ	207	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
	208	ref = btrfs_item_ptr(leaf, path->slots[0],
	209	struct btrfs_root_ref);
	210	key.objectid = btrfs_root_ref_dirid(leaf, ref);
	211	} else {
	212	key.objectid = found_key.offset;
	213	}
be6e8dc0 BR	214	btrfs_free_path(path);
be6e8dc0 BR	215
76dda93c YZ	216	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {
	217	return btrfs_get_dentry(root->fs_info->sb, key.objectid,
	218	found_key.offset, 0, 0);
	219	}
2d4d9fbd	220
76dda93c	221	key.type = BTRFS_INODE_ITEM_KEY;
be6e8dc0	222	key.offset = 0;
af53d29a	223	return d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
76dda93c YZ	224	fail:
	225	btrfs_free_path(path);
	226	return ERR_PTR(ret);
be6e8dc0 BR	227	}
be6e8dc0 BR	228
2ede0daf JB	229	static int btrfs_get_name(struct dentry parent, char name,
	230	struct dentry *child)
	231	{
	232	struct inode *inode = child->d_inode;
	233	struct inode *dir = parent->d_inode;
	234	struct btrfs_path *path;
	235	struct btrfs_root *root = BTRFS_I(dir)->root;
	236	struct btrfs_inode_ref *iref;
	237	struct btrfs_root_ref *rref;
	238	struct extent_buffer *leaf;
	239	unsigned long name_ptr;
	240	struct btrfs_key key;
	241	int name_len;
	242	int ret;
33345d01	243	u64 ino;
2ede0daf JB	244
	245	if (!dir \|\| !inode)
	246	return -EINVAL;
	247
	248	if (!S_ISDIR(dir->i_mode))
	249	return -EINVAL;
	250
33345d01 LZ	251	ino = btrfs_ino(inode);
33345d01 LZ	252
2ede0daf JB	253	path = btrfs_alloc_path();
	254	if (!path)
	255	return -ENOMEM;
	256	path->leave_spinning = 1;
	257
33345d01	258	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
2ede0daf JB	259	key.objectid = BTRFS_I(inode)->root->root_key.objectid;
	260	key.type = BTRFS_ROOT_BACKREF_KEY;
	261	key.offset = (u64)-1;
	262	root = root->fs_info->tree_root;
	263	} else {
33345d01 LZ	264	key.objectid = ino;
33345d01 LZ	265	key.offset = btrfs_ino(dir);
2ede0daf JB	266	key.type = BTRFS_INODE_REF_KEY;
	267	}
	268
	269	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	270	if (ret < 0) {
	271	btrfs_free_path(path);
	272	return ret;
	273	} else if (ret > 0) {
33345d01	274	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
2ede0daf JB	275	path->slots[0]--;
	276	} else {
	277	btrfs_free_path(path);
	278	return -ENOENT;
	279	}
	280	}
	281	leaf = path->nodes[0];
	282
33345d01 LZ	283	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
33345d01 LZ	284	rref = btrfs_item_ptr(leaf, path->slots[0],
2ede0daf	285	struct btrfs_root_ref);
33345d01 LZ	286	name_ptr = (unsigned long)(rref + 1);
33345d01 LZ	287	name_len = btrfs_root_ref_name_len(leaf, rref);
2ede0daf JB	288	} else {
	289	iref = btrfs_item_ptr(leaf, path->slots[0],
	290	struct btrfs_inode_ref);
	291	name_ptr = (unsigned long)(iref + 1);
	292	name_len = btrfs_inode_ref_name_len(leaf, iref);
	293	}
	294
	295	read_extent_buffer(leaf, name, name_ptr, name_len);
	296	btrfs_free_path(path);
	297
	298	/*
	299	* have to add the null termination to make sure that reconnect_path
	300	* gets the right len for strlen
	301	*/
	302	name[name_len] = '\0';
	303
	304	return 0;
	305	}
	306
be6e8dc0 BR	307	const struct export_operations btrfs_export_ops = {
	308	.encode_fh = btrfs_encode_fh,
	309	.fh_to_dentry = btrfs_fh_to_dentry,
	310	.fh_to_parent = btrfs_fh_to_parent,
	311	.get_parent = btrfs_get_parent,
2ede0daf	312	.get_name = btrfs_get_name,
be6e8dc0	313	};