[linux-block.git] / fs / btrfs / xattr.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2007 Red Hat.  All rights reserved.
 */

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/rwsem.h>
#include <linux/xattr.h>
#include <linux/security.h>
#include <linux/posix_acl_xattr.h>
#include <linux/iversion.h>
#include <linux/sched/mm.h>
#include "ctree.h"
#include "btrfs_inode.h"
#include "transaction.h"
#include "xattr.h"
#include "disk-io.h"
#include "props.h"
#include "locking.h"

int btrfs_getxattr(struct inode *inode, const char *name,
				void *buffer, size_t size)
{
	struct btrfs_dir_item *di;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_path *path;
	struct extent_buffer *leaf;
	int ret = 0;
	unsigned long data_ptr;

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

	/* lookup the xattr by name */
	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
			name, strlen(name), 0);
	if (!di) {
		ret = -ENODATA;
		goto out;
	} else if (IS_ERR(di)) {
		ret = PTR_ERR(di);
		goto out;
	}

	leaf = path->nodes[0];
	/* if size is 0, that means we want the size of the attr */
	if (!size) {
		ret = btrfs_dir_data_len(leaf, di);
		goto out;
	}

	/* now get the data out of our dir_item */
	if (btrfs_dir_data_len(leaf, di) > size) {
		ret = -ERANGE;
		goto out;
	}

	/*
	 * The way things are packed into the leaf is like this
	 * |struct btrfs_dir_item|name|data|
	 * where name is the xattr name, so security.foo, and data is the
	 * content of the xattr.  data_ptr points to the location in memory
	 * where the data starts in the in memory leaf
	 */
	data_ptr = (unsigned long)((char *)(di + 1) +
				   btrfs_dir_name_len(leaf, di));
	read_extent_buffer(leaf, buffer, data_ptr,
			   btrfs_dir_data_len(leaf, di));
	ret = btrfs_dir_data_len(leaf, di);

out:
	btrfs_free_path(path);
	return ret;
}

int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode,
		   const char *name, const void *value, size_t size, int flags)
{
	struct btrfs_dir_item *di = NULL;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct btrfs_path *path;
	size_t name_len = strlen(name);
	int ret = 0;

	ASSERT(trans);

	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
		return -ENOSPC;

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

	if (!value) {
		di = btrfs_lookup_xattr(trans, root, path,
				btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
		if (!di && (flags & XATTR_REPLACE))
			ret = -ENODATA;
		else if (IS_ERR(di))
			ret = PTR_ERR(di);
		else if (di)
			ret = btrfs_delete_one_dir_name(trans, root, path, di);
		goto out;
	}

	/*
	 * For a replace we can't just do the insert blindly.
	 * Do a lookup first (read-only btrfs_search_slot), and return if xattr
	 * doesn't exist. If it exists, fall down below to the insert/replace
	 * path - we can't race with a concurrent xattr delete, because the VFS
	 * locks the inode's i_mutex before calling setxattr or removexattr.
	 */
	if (flags & XATTR_REPLACE) {
		ASSERT(inode_is_locked(inode));
		di = btrfs_lookup_xattr(NULL, root, path,
				btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
		if (!di)
			ret = -ENODATA;
		else if (IS_ERR(di))
			ret = PTR_ERR(di);
		if (ret)
			goto out;
		btrfs_release_path(path);
		di = NULL;
	}

	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
				      name, name_len, value, size);
	if (ret == -EOVERFLOW) {
		/*
		 * We have an existing item in a leaf, split_leaf couldn't
		 * expand it. That item might have or not a dir_item that
		 * matches our target xattr, so lets check.
		 */
		ret = 0;
		btrfs_assert_tree_locked(path->nodes[0]);
		di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
		if (!di && !(flags & XATTR_REPLACE)) {
			ret = -ENOSPC;
			goto out;
		}
	} else if (ret == -EEXIST) {
		ret = 0;
		di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
		ASSERT(di); /* logic error */
	} else if (ret) {
		goto out;
	}

	if (di && (flags & XATTR_CREATE)) {
		ret = -EEXIST;
		goto out;
	}

	if (di) {
		/*
		 * We're doing a replace, and it must be atomic, that is, at
		 * any point in time we have either the old or the new xattr
		 * value in the tree. We don't want readers (getxattr and
		 * listxattrs) to miss a value, this is specially important
		 * for ACLs.
		 */
		const int slot = path->slots[0];
		struct extent_buffer *leaf = path->nodes[0];
		const u16 old_data_len = btrfs_dir_data_len(leaf, di);
		const u32 item_size = btrfs_item_size_nr(leaf, slot);
		const u32 data_size = sizeof(*di) + name_len + size;
		struct btrfs_item *item;
		unsigned long data_ptr;
		char *ptr;

		if (size > old_data_len) {
			if (btrfs_leaf_free_space(leaf) <
			    (size - old_data_len)) {
				ret = -ENOSPC;
				goto out;
			}
		}

		if (old_data_len + name_len + sizeof(*di) == item_size) {
			/* No other xattrs packed in the same leaf item. */
			if (size > old_data_len)
				btrfs_extend_item(path, size - old_data_len);
			else if (size < old_data_len)
				btrfs_truncate_item(path, data_size, 1);
		} else {
			/* There are other xattrs packed in the same item. */
			ret = btrfs_delete_one_dir_name(trans, root, path, di);
			if (ret)
				goto out;
			btrfs_extend_item(path, data_size);
		}

		item = btrfs_item_nr(slot);
		ptr = btrfs_item_ptr(leaf, slot, char);
		ptr += btrfs_item_size(leaf, item) - data_size;
		di = (struct btrfs_dir_item *)ptr;
		btrfs_set_dir_data_len(leaf, di, size);
		data_ptr = ((unsigned long)(di + 1)) + name_len;
		write_extent_buffer(leaf, value, data_ptr, size);
		btrfs_mark_buffer_dirty(leaf);
	} else {
		/*
		 * Insert, and we had space for the xattr, so path->slots[0] is
		 * where our xattr dir_item is and btrfs_insert_xattr_item()
		 * filled it.
		 */
	}
out:
	btrfs_free_path(path);
	if (!ret)
		set_bit(BTRFS_INODE_COPY_EVERYTHING,
			&BTRFS_I(inode)->runtime_flags);
	return ret;
}

/*
 * @value: "" makes the attribute to empty, NULL removes it
 */
int btrfs_setxattr_trans(struct inode *inode, const char *name,
			 const void *value, size_t size, int flags)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_trans_handle *trans;
	int ret;

	trans = btrfs_start_transaction(root, 2);
	if (IS_ERR(trans))
		return PTR_ERR(trans);

	ret = btrfs_setxattr(trans, inode, name, value, size, flags);
	if (ret)
		goto out;

	inode_inc_iversion(inode);
	inode->i_ctime = current_time(inode);
	ret = btrfs_update_inode(trans, root, inode);
	BUG_ON(ret);
out:
	btrfs_end_transaction(trans);
	return ret;
}

ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
	struct btrfs_key key;
	struct inode *inode = d_inode(dentry);
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_path *path;
	int ret = 0;
	size_t total_size = 0, size_left = size;

	/*
	 * ok we want all objects associated with this id.
	 * NOTE: we set key.offset = 0; because we want to start with the
	 * first xattr that we find and walk forward
	 */
	key.objectid = btrfs_ino(BTRFS_I(inode));
	key.type = BTRFS_XATTR_ITEM_KEY;
	key.offset = 0;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	path->reada = READA_FORWARD;

	/* search for our xattrs */
	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		goto err;

	while (1) {
		struct extent_buffer *leaf;
		int slot;
		struct btrfs_dir_item *di;
		struct btrfs_key found_key;
		u32 item_size;
		u32 cur;

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

		/* this is where we start walking through the path */
		if (slot >= btrfs_header_nritems(leaf)) {
			/*
			 * if we've reached the last slot in this leaf we need
			 * to go to the next leaf and reset everything
			 */
			ret = btrfs_next_leaf(root, path);
			if (ret < 0)
				goto err;
			else if (ret > 0)
				break;
			continue;
		}

		btrfs_item_key_to_cpu(leaf, &found_key, slot);

		/* check to make sure this item is what we want */
		if (found_key.objectid != key.objectid)
			break;
		if (found_key.type > BTRFS_XATTR_ITEM_KEY)
			break;
		if (found_key.type < BTRFS_XATTR_ITEM_KEY)
			goto next_item;

		di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
		item_size = btrfs_item_size_nr(leaf, slot);
		cur = 0;
		while (cur < item_size) {
			u16 name_len = btrfs_dir_name_len(leaf, di);
			u16 data_len = btrfs_dir_data_len(leaf, di);
			u32 this_len = sizeof(*di) + name_len + data_len;
			unsigned long name_ptr = (unsigned long)(di + 1);

			total_size += name_len + 1;
			/*
			 * We are just looking for how big our buffer needs to
			 * be.
			 */
			if (!size)
				goto next;

			if (!buffer || (name_len + 1) > size_left) {
				ret = -ERANGE;
				goto err;
			}

			read_extent_buffer(leaf, buffer, name_ptr, name_len);
			buffer[name_len] = '\0';

			size_left -= name_len + 1;
			buffer += name_len + 1;
next:
			cur += this_len;
			di = (struct btrfs_dir_item *)((char *)di + this_len);
		}
next_item:
		path->slots[0]++;
	}
	ret = total_size;

err:
	btrfs_free_path(path);

	return ret;
}

static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
				   struct dentry *unused, struct inode *inode,
				   const char *name, void *buffer, size_t size)
{
	name = xattr_full_name(handler, name);
	return btrfs_getxattr(inode, name, buffer, size);
}

static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
				   struct dentry *unused, struct inode *inode,
				   const char *name, const void *buffer,
				   size_t size, int flags)
{
	name = xattr_full_name(handler, name);
	return btrfs_setxattr_trans(inode, name, buffer, size, flags);
}

static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
					struct dentry *unused, struct inode *inode,
					const char *name, const void *value,
					size_t size, int flags)
{
	int ret;
	struct btrfs_trans_handle *trans;
	struct btrfs_root *root = BTRFS_I(inode)->root;

	name = xattr_full_name(handler, name);
	ret = btrfs_validate_prop(name, value, size);
	if (ret)
		return ret;

	trans = btrfs_start_transaction(root, 2);
	if (IS_ERR(trans))
		return PTR_ERR(trans);

	ret = btrfs_set_prop(trans, inode, name, value, size, flags);
	if (!ret) {
		inode_inc_iversion(inode);
		inode->i_ctime = current_time(inode);
		ret = btrfs_update_inode(trans, root, inode);
		BUG_ON(ret);
	}

	btrfs_end_transaction(trans);

	return ret;
}

static const struct xattr_handler btrfs_security_xattr_handler = {
	.prefix = XATTR_SECURITY_PREFIX,
	.get = btrfs_xattr_handler_get,
	.set = btrfs_xattr_handler_set,
};

static const struct xattr_handler btrfs_trusted_xattr_handler = {
	.prefix = XATTR_TRUSTED_PREFIX,
	.get = btrfs_xattr_handler_get,
	.set = btrfs_xattr_handler_set,
};

static const struct xattr_handler btrfs_user_xattr_handler = {
	.prefix = XATTR_USER_PREFIX,
	.get = btrfs_xattr_handler_get,
	.set = btrfs_xattr_handler_set,
};

static const struct xattr_handler btrfs_btrfs_xattr_handler = {
	.prefix = XATTR_BTRFS_PREFIX,
	.get = btrfs_xattr_handler_get,
	.set = btrfs_xattr_handler_set_prop,
};

const struct xattr_handler *btrfs_xattr_handlers[] = {
	&btrfs_security_xattr_handler,
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
	&posix_acl_access_xattr_handler,
	&posix_acl_default_xattr_handler,
#endif
	&btrfs_trusted_xattr_handler,
	&btrfs_user_xattr_handler,
	&btrfs_btrfs_xattr_handler,
	NULL,
};

static int btrfs_initxattrs(struct inode *inode,
			    const struct xattr *xattr_array, void *fs_private)
{
	struct btrfs_trans_handle *trans = fs_private;
	const struct xattr *xattr;
	unsigned int nofs_flag;
	char *name;
	int err = 0;

	/*
	 * We're holding a transaction handle, so use a NOFS memory allocation
	 * context to avoid deadlock if reclaim happens.
	 */
	nofs_flag = memalloc_nofs_save();
	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
		name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
			       strlen(xattr->name) + 1, GFP_KERNEL);
		if (!name) {
			err = -ENOMEM;
			break;
		}
		strcpy(name, XATTR_SECURITY_PREFIX);
		strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
		err = btrfs_setxattr(trans, inode, name, xattr->value,
				     xattr->value_len, 0);
		kfree(name);
		if (err < 0)
			break;
	}
	memalloc_nofs_restore(nofs_flag);
	return err;
}

int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
			      struct inode *inode, struct inode *dir,
			      const struct qstr *qstr)
{
	return security_inode_init_security(inode, dir, qstr,
					    &btrfs_initxattrs, trans);
}
Commit	Line	Data
c1d7c514	1	// SPDX-License-Identifier: GPL-2.0
5103e947 JB	2	/*
5103e947 JB	3	* Copyright (C) 2007 Red Hat. All rights reserved.
5103e947 JB	4	*/
	5
	6	#include <linux/init.h>
	7	#include <linux/fs.h>
	8	#include <linux/slab.h>
	9	#include <linux/rwsem.h>
	10	#include <linux/xattr.h>
0279b4cd	11	#include <linux/security.h>
996a710d	12	#include <linux/posix_acl_xattr.h>
ae5e165d	13	#include <linux/iversion.h>
827aa18e	14	#include <linux/sched/mm.h>
5103e947 JB	15	#include "ctree.h"
	16	#include "btrfs_inode.h"
	17	#include "transaction.h"
	18	#include "xattr.h"
	19	#include "disk-io.h"
63541927	20	#include "props.h"
5f5bc6b1	21	#include "locking.h"
33268eaf	22
bcadd705	23	int btrfs_getxattr(struct inode inode, const char name,
95819c05	24	void *buffer, size_t size)
5103e947 JB	25	{
	26	struct btrfs_dir_item *di;
	27	struct btrfs_root *root = BTRFS_I(inode)->root;
	28	struct btrfs_path *path;
	29	struct extent_buffer *leaf;
5103e947 JB	30	int ret = 0;
5103e947 JB	31	unsigned long data_ptr;
5103e947 JB	32
5103e947 JB	33	path = btrfs_alloc_path();
95819c05	34	if (!path)
5103e947	35	return -ENOMEM;
5103e947	36
5103e947	37	/* lookup the xattr by name */
f85b7379 DS	38	di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
f85b7379 DS	39	name, strlen(name), 0);
07060404	40	if (!di) {
5103e947 JB	41	ret = -ENODATA;
5103e947 JB	42	goto out;
07060404 JB	43	} else if (IS_ERR(di)) {
	44	ret = PTR_ERR(di);
	45	goto out;
5103e947 JB	46	}
	47
	48	leaf = path->nodes[0];
	49	/* if size is 0, that means we want the size of the attr */
	50	if (!size) {
	51	ret = btrfs_dir_data_len(leaf, di);
	52	goto out;
	53	}
	54
	55	/* now get the data out of our dir_item */
	56	if (btrfs_dir_data_len(leaf, di) > size) {
	57	ret = -ERANGE;
	58	goto out;
	59	}
07060404 JB	60
	61	/*
	62	* The way things are packed into the leaf is like this
	63	* \|struct btrfs_dir_item\|name\|data\|
	64	* where name is the xattr name, so security.foo, and data is the
	65	* content of the xattr. data_ptr points to the location in memory
	66	* where the data starts in the in memory leaf
	67	*/
5103e947 JB	68	data_ptr = (unsigned long)((char *)(di + 1) +
	69	btrfs_dir_name_len(leaf, di));
	70	read_extent_buffer(leaf, buffer, data_ptr,
3acd7ee8	71	btrfs_dir_data_len(leaf, di));
5103e947 JB	72	ret = btrfs_dir_data_len(leaf, di);
	73
	74	out:
5103e947 JB	75	btrfs_free_path(path);
	76	return ret;
	77	}
	78
3e125a74 AJ	79	int btrfs_setxattr(struct btrfs_trans_handle trans, struct inode inode,
3e125a74 AJ	80	const char name, const void value, size_t size, int flags)
5103e947	81	{
5f5bc6b1	82	struct btrfs_dir_item *di = NULL;
5103e947	83	struct btrfs_root *root = BTRFS_I(inode)->root;
2ff7e61e	84	struct btrfs_fs_info *fs_info = root->fs_info;
5103e947	85	struct btrfs_path *path;
f34f57a3 YZ	86	size_t name_len = strlen(name);
	87	int ret = 0;
	88
04e6863b AJ	89	ASSERT(trans);
04e6863b AJ	90
da17066c	91	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
f34f57a3	92	return -ENOSPC;
5103e947 JB	93
5103e947 JB	94	path = btrfs_alloc_path();
95819c05	95	if (!path)
5103e947	96	return -ENOMEM;
5f5bc6b1 FM	97	path->skip_release_on_error = 1;
	98
	99	if (!value) {
f85b7379 DS	100	di = btrfs_lookup_xattr(trans, root, path,
f85b7379 DS	101	btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
5f5bc6b1 FM	102	if (!di && (flags & XATTR_REPLACE))
5f5bc6b1 FM	103	ret = -ENODATA;
5cdf83ed FM	104	else if (IS_ERR(di))
5cdf83ed FM	105	ret = PTR_ERR(di);
5f5bc6b1 FM	106	else if (di)
	107	ret = btrfs_delete_one_dir_name(trans, root, path, di);
	108	goto out;
	109	}
5103e947	110
5f5bc6b1 FM	111	/*
	112	* For a replace we can't just do the insert blindly.
	113	* Do a lookup first (read-only btrfs_search_slot), and return if xattr
	114	* doesn't exist. If it exists, fall down below to the insert/replace
	115	* path - we can't race with a concurrent xattr delete, because the VFS
	116	* locks the inode's i_mutex before calling setxattr or removexattr.
	117	*/
fa09200b	118	if (flags & XATTR_REPLACE) {
5955102c	119	ASSERT(inode_is_locked(inode));
f85b7379 DS	120	di = btrfs_lookup_xattr(NULL, root, path,
f85b7379 DS	121	btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
5cdf83ed	122	if (!di)
fa09200b	123	ret = -ENODATA;
5cdf83ed FM	124	else if (IS_ERR(di))
	125	ret = PTR_ERR(di);
	126	if (ret)
5103e947	127	goto out;
b3b4aa74	128	btrfs_release_path(path);
5f5bc6b1 FM	129	di = NULL;
5f5bc6b1 FM	130	}
4815053a	131
4a0cc7ca	132	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
5f5bc6b1 FM	133	name, name_len, value, size);
5f5bc6b1 FM	134	if (ret == -EOVERFLOW) {
4815053a	135	/*
5f5bc6b1 FM	136	* We have an existing item in a leaf, split_leaf couldn't
	137	* expand it. That item might have or not a dir_item that
	138	* matches our target xattr, so lets check.
4815053a	139	*/
5f5bc6b1 FM	140	ret = 0;
5f5bc6b1 FM	141	btrfs_assert_tree_locked(path->nodes[0]);
2ff7e61e	142	di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
5f5bc6b1 FM	143	if (!di && !(flags & XATTR_REPLACE)) {
5f5bc6b1 FM	144	ret = -ENOSPC;
01e6deb2 LB	145	goto out;
01e6deb2 LB	146	}
5f5bc6b1 FM	147	} else if (ret == -EEXIST) {
5f5bc6b1 FM	148	ret = 0;
2ff7e61e	149	di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
5f5bc6b1 FM	150	ASSERT(di); /* logic error */
	151	} else if (ret) {
	152	goto out;
fa09200b	153	}
5103e947	154
5f5bc6b1	155	if (di && (flags & XATTR_CREATE)) {
ed3ee9f4	156	ret = -EEXIST;
5f5bc6b1 FM	157	goto out;
5f5bc6b1 FM	158	}
ed3ee9f4	159
5f5bc6b1	160	if (di) {
fa09200b	161	/*
5f5bc6b1 FM	162	* We're doing a replace, and it must be atomic, that is, at
	163	* any point in time we have either the old or the new xattr
	164	* value in the tree. We don't want readers (getxattr and
	165	* listxattrs) to miss a value, this is specially important
	166	* for ACLs.
fa09200b	167	*/
5f5bc6b1 FM	168	const int slot = path->slots[0];
	169	struct extent_buffer *leaf = path->nodes[0];
	170	const u16 old_data_len = btrfs_dir_data_len(leaf, di);
	171	const u32 item_size = btrfs_item_size_nr(leaf, slot);
	172	const u32 data_size = sizeof(*di) + name_len + size;
	173	struct btrfs_item *item;
	174	unsigned long data_ptr;
	175	char *ptr;
	176
	177	if (size > old_data_len) {
e902baac	178	if (btrfs_leaf_free_space(leaf) <
5f5bc6b1 FM	179	(size - old_data_len)) {
	180	ret = -ENOSPC;
	181	goto out;
	182	}
fa09200b	183	}
33268eaf	184
5f5bc6b1 FM	185	if (old_data_len + name_len + sizeof(*di) == item_size) {
	186	/* No other xattrs packed in the same leaf item. */
	187	if (size > old_data_len)
c71dd880	188	btrfs_extend_item(path, size - old_data_len);
5f5bc6b1	189	else if (size < old_data_len)
78ac4f9e	190	btrfs_truncate_item(path, data_size, 1);
5f5bc6b1 FM	191	} else {
	192	/* There are other xattrs packed in the same item. */
	193	ret = btrfs_delete_one_dir_name(trans, root, path, di);
	194	if (ret)
	195	goto out;
c71dd880	196	btrfs_extend_item(path, data_size);
5f5bc6b1	197	}
fa09200b	198
5f5bc6b1 FM	199	item = btrfs_item_nr(slot);
	200	ptr = btrfs_item_ptr(leaf, slot, char);
	201	ptr += btrfs_item_size(leaf, item) - data_size;
	202	di = (struct btrfs_dir_item *)ptr;
	203	btrfs_set_dir_data_len(leaf, di, size);
	204	data_ptr = ((unsigned long)(di + 1)) + name_len;
	205	write_extent_buffer(leaf, value, data_ptr, size);
	206	btrfs_mark_buffer_dirty(leaf);
	207	} else {
fa09200b	208	/*
5f5bc6b1 FM	209	* Insert, and we had space for the xattr, so path->slots[0] is
	210	* where our xattr dir_item is and btrfs_insert_xattr_item()
	211	* filled it.
fa09200b	212	*/
5103e947	213	}
f34f57a3 YZ	214	out:
f34f57a3 YZ	215	btrfs_free_path(path);
3763771c FM	216	if (!ret)
	217	set_bit(BTRFS_INODE_COPY_EVERYTHING,
	218	&BTRFS_I(inode)->runtime_flags);
f34f57a3 YZ	219	return ret;
	220	}
	221
4815053a DS	222	/*
	223	* @value: "" makes the attribute to empty, NULL removes it
	224	*/
e3de9b15	225	int btrfs_setxattr_trans(struct inode inode, const char name,
cac237ae	226	const void *value, size_t size, int flags)
f34f57a3 YZ	227	{
f34f57a3 YZ	228	struct btrfs_root *root = BTRFS_I(inode)->root;
e3de9b15	229	struct btrfs_trans_handle *trans;
f34f57a3 YZ	230	int ret;
f34f57a3 YZ	231
a22285a6 YZ	232	trans = btrfs_start_transaction(root, 2);
	233	if (IS_ERR(trans))
	234	return PTR_ERR(trans);
5103e947	235
2d74fa3e	236	ret = btrfs_setxattr(trans, inode, name, value, size, flags);
f34f57a3 YZ	237	if (ret)
	238	goto out;
	239
0c4d2d95	240	inode_inc_iversion(inode);
c2050a45	241	inode->i_ctime = current_time(inode);
f34f57a3 YZ	242	ret = btrfs_update_inode(trans, root, inode);
	243	BUG_ON(ret);
	244	out:
3a45bb20	245	btrfs_end_transaction(trans);
5103e947 JB	246	return ret;
	247	}
	248
	249	ssize_t btrfs_listxattr(struct dentry dentry, char buffer, size_t size)
	250	{
daac7ba6	251	struct btrfs_key key;
2b0143b5	252	struct inode *inode = d_inode(dentry);
5103e947 JB	253	struct btrfs_root *root = BTRFS_I(inode)->root;
5103e947 JB	254	struct btrfs_path *path;
daac7ba6	255	int ret = 0;
eaa47d86	256	size_t total_size = 0, size_left = size;
5103e947 JB	257
	258	/*
	259	* ok we want all objects associated with this id.
	260	* NOTE: we set key.offset = 0; because we want to start with the
	261	* first xattr that we find and walk forward
	262	*/
4a0cc7ca	263	key.objectid = btrfs_ino(BTRFS_I(inode));
962a298f	264	key.type = BTRFS_XATTR_ITEM_KEY;
5103e947 JB	265	key.offset = 0;
	266
	267	path = btrfs_alloc_path();
5103e947 JB	268	if (!path)
5103e947 JB	269	return -ENOMEM;
e4058b54	270	path->reada = READA_FORWARD;
5103e947	271
5103e947 JB	272	/* search for our xattrs */
	273	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	274	if (ret < 0)
	275	goto err;
2e6a0035	276
5103e947	277	while (1) {
daac7ba6 FM	278	struct extent_buffer *leaf;
	279	int slot;
	280	struct btrfs_dir_item *di;
	281	struct btrfs_key found_key;
	282	u32 item_size;
	283	u32 cur;
	284
5103e947	285	leaf = path->nodes[0];
5103e947 JB	286	slot = path->slots[0];
	287
	288	/* this is where we start walking through the path */
2e6a0035	289	if (slot >= btrfs_header_nritems(leaf)) {
5103e947 JB	290	/*
	291	* if we've reached the last slot in this leaf we need
	292	* to go to the next leaf and reset everything
	293	*/
2e6a0035 LZ	294	ret = btrfs_next_leaf(root, path);
	295	if (ret < 0)
	296	goto err;
	297	else if (ret > 0)
	298	break;
	299	continue;
5103e947	300	}
5103e947	301
5103e947 JB	302	btrfs_item_key_to_cpu(leaf, &found_key, slot);
	303
	304	/* check to make sure this item is what we want */
	305	if (found_key.objectid != key.objectid)
	306	break;
f1cd1f0b	307	if (found_key.type > BTRFS_XATTR_ITEM_KEY)
5103e947	308	break;
f1cd1f0b	309	if (found_key.type < BTRFS_XATTR_ITEM_KEY)
daac7ba6	310	goto next_item;
5103e947 JB	311
5103e947 JB	312	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
daac7ba6 FM	313	item_size = btrfs_item_size_nr(leaf, slot);
	314	cur = 0;
	315	while (cur < item_size) {
	316	u16 name_len = btrfs_dir_name_len(leaf, di);
	317	u16 data_len = btrfs_dir_data_len(leaf, di);
	318	u32 this_len = sizeof(*di) + name_len + data_len;
	319	unsigned long name_ptr = (unsigned long)(di + 1);
	320
daac7ba6 FM	321	total_size += name_len + 1;
	322	/*
	323	* We are just looking for how big our buffer needs to
	324	* be.
	325	*/
	326	if (!size)
	327	goto next;
5103e947	328
daac7ba6 FM	329	if (!buffer \|\| (name_len + 1) > size_left) {
	330	ret = -ERANGE;
	331	goto err;
	332	}
5103e947	333
daac7ba6 FM	334	read_extent_buffer(leaf, buffer, name_ptr, name_len);
daac7ba6 FM	335	buffer[name_len] = '\0';
eaa47d86	336
daac7ba6 FM	337	size_left -= name_len + 1;
daac7ba6 FM	338	buffer += name_len + 1;
2e6a0035	339	next:
daac7ba6 FM	340	cur += this_len;
	341	di = (struct btrfs_dir_item )((char )di + this_len);
	342	}
	343	next_item:
2e6a0035	344	path->slots[0]++;
5103e947 JB	345	}
	346	ret = total_size;
	347
	348	err:
5103e947 JB	349	btrfs_free_path(path);
	350
	351	return ret;
	352	}
	353
9172abbc	354	static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
b296821a AV	355	struct dentry unused, struct inode inode,
b296821a AV	356	const char name, void buffer, size_t size)
95819c05	357	{
9172abbc	358	name = xattr_full_name(handler, name);
7852781d	359	return btrfs_getxattr(inode, name, buffer, size);
69a32ac5 CM	360	}
69a32ac5 CM	361
9172abbc	362	static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
59301226 AV	363	struct dentry unused, struct inode inode,
	364	const char name, const void buffer,
	365	size_t size, int flags)
95819c05	366	{
9172abbc	367	name = xattr_full_name(handler, name);
e3de9b15	368	return btrfs_setxattr_trans(inode, name, buffer, size, flags);
9172abbc	369	}
5103e947	370
9172abbc	371	static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
59301226	372	struct dentry unused, struct inode inode,
9172abbc AG	373	const char name, const void value,
	374	size_t size, int flags)
	375	{
f22125e5	376	int ret;
b3f6a4be AJ	377	struct btrfs_trans_handle *trans;
b3f6a4be AJ	378	struct btrfs_root *root = BTRFS_I(inode)->root;
f22125e5	379
9172abbc	380	name = xattr_full_name(handler, name);
f22125e5 AJ	381	ret = btrfs_validate_prop(name, value, size);
	382	if (ret)
	383	return ret;
b3f6a4be AJ	384
	385	trans = btrfs_start_transaction(root, 2);
	386	if (IS_ERR(trans))
	387	return PTR_ERR(trans);
	388
	389	ret = btrfs_set_prop(trans, inode, name, value, size, flags);
	390	if (!ret) {
	391	inode_inc_iversion(inode);
	392	inode->i_ctime = current_time(inode);
b3f6a4be AJ	393	ret = btrfs_update_inode(trans, root, inode);
	394	BUG_ON(ret);
	395	}
	396
	397	btrfs_end_transaction(trans);
	398
	399	return ret;
95819c05	400	}
5103e947	401
9172abbc AG	402	static const struct xattr_handler btrfs_security_xattr_handler = {
	403	.prefix = XATTR_SECURITY_PREFIX,
	404	.get = btrfs_xattr_handler_get,
	405	.set = btrfs_xattr_handler_set,
	406	};
	407
	408	static const struct xattr_handler btrfs_trusted_xattr_handler = {
	409	.prefix = XATTR_TRUSTED_PREFIX,
	410	.get = btrfs_xattr_handler_get,
	411	.set = btrfs_xattr_handler_set,
	412	};
	413
	414	static const struct xattr_handler btrfs_user_xattr_handler = {
	415	.prefix = XATTR_USER_PREFIX,
	416	.get = btrfs_xattr_handler_get,
	417	.set = btrfs_xattr_handler_set,
	418	};
	419
	420	static const struct xattr_handler btrfs_btrfs_xattr_handler = {
	421	.prefix = XATTR_BTRFS_PREFIX,
	422	.get = btrfs_xattr_handler_get,
	423	.set = btrfs_xattr_handler_set_prop,
	424	};
	425
	426	const struct xattr_handler *btrfs_xattr_handlers[] = {
	427	&btrfs_security_xattr_handler,
	428	#ifdef CONFIG_BTRFS_FS_POSIX_ACL
	429	&posix_acl_access_xattr_handler,
	430	&posix_acl_default_xattr_handler,
	431	#endif
	432	&btrfs_trusted_xattr_handler,
	433	&btrfs_user_xattr_handler,
	434	&btrfs_btrfs_xattr_handler,
	435	NULL,
	436	};
	437
48a3b636	438	static int btrfs_initxattrs(struct inode *inode,
419a6f30	439	const struct xattr xattr_array, void fs_private)
0279b4cd	440	{
419a6f30	441	struct btrfs_trans_handle *trans = fs_private;
9d8f13ba	442	const struct xattr *xattr;
827aa18e	443	unsigned int nofs_flag;
0279b4cd	444	char *name;
9d8f13ba	445	int err = 0;
0279b4cd	446
827aa18e FM	447	/*
	448	* We're holding a transaction handle, so use a NOFS memory allocation
	449	* context to avoid deadlock if reclaim happens.
	450	*/
	451	nofs_flag = memalloc_nofs_save();
9d8f13ba MZ	452	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
9d8f13ba MZ	453	name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
39a27ec1	454	strlen(xattr->name) + 1, GFP_KERNEL);
9d8f13ba MZ	455	if (!name) {
	456	err = -ENOMEM;
	457	break;
	458	}
0279b4cd	459	strcpy(name, XATTR_SECURITY_PREFIX);
9d8f13ba	460	strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
04e6863b AJ	461	err = btrfs_setxattr(trans, inode, name, xattr->value,
04e6863b AJ	462	xattr->value_len, 0);
0279b4cd	463	kfree(name);
9d8f13ba MZ	464	if (err < 0)
9d8f13ba MZ	465	break;
0279b4cd	466	}
827aa18e	467	memalloc_nofs_restore(nofs_flag);
0279b4cd JO	468	return err;
0279b4cd JO	469	}
9d8f13ba MZ	470
	471	int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
	472	struct inode inode, struct inode dir,
	473	const struct qstr *qstr)
	474	{
	475	return security_inode_init_security(inode, dir, qstr,
	476	&btrfs_initxattrs, trans);
	477	}