[linux-2.6-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;
}

static int do_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;

	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(fs_info, 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(fs_info, path,
						  size - old_data_len);
			else if (size < old_data_len)
				btrfs_truncate_item(fs_info, 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(fs_info, 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);
	return ret;
}

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

	if (btrfs_root_readonly(root))
		return -EROFS;

	if (trans)
		return do_setxattr(trans, inode, name, value, size, flags);

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

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

	inode_inc_iversion(inode);
	inode->i_ctime = current_time(inode);
	set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
	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(NULL, 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)
{
	name = xattr_full_name(handler, name);
	return btrfs_set_prop(inode, name, value, size, flags);
}

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_info)
{
	const struct xattr *xattr;
	struct btrfs_trans_handle *trans = fs_info;
	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
f34f57a3 YZ	79	static int do_setxattr(struct btrfs_trans_handle *trans,
	80	struct inode inode, const char name,
	81	const void *value, size_t size, int flags)
5103e947	82	{
5f5bc6b1	83	struct btrfs_dir_item *di = NULL;
5103e947	84	struct btrfs_root *root = BTRFS_I(inode)->root;
2ff7e61e	85	struct btrfs_fs_info *fs_info = root->fs_info;
5103e947	86	struct btrfs_path *path;
f34f57a3 YZ	87	size_t name_len = strlen(name);
	88	int ret = 0;
	89
da17066c	90	if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
f34f57a3	91	return -ENOSPC;
5103e947 JB	92
5103e947 JB	93	path = btrfs_alloc_path();
95819c05	94	if (!path)
5103e947	95	return -ENOMEM;
5f5bc6b1 FM	96	path->skip_release_on_error = 1;
	97
	98	if (!value) {
f85b7379 DS	99	di = btrfs_lookup_xattr(trans, root, path,
f85b7379 DS	100	btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
5f5bc6b1 FM	101	if (!di && (flags & XATTR_REPLACE))
5f5bc6b1 FM	102	ret = -ENODATA;
5cdf83ed FM	103	else if (IS_ERR(di))
5cdf83ed FM	104	ret = PTR_ERR(di);
5f5bc6b1 FM	105	else if (di)
	106	ret = btrfs_delete_one_dir_name(trans, root, path, di);
	107	goto out;
	108	}
5103e947	109
5f5bc6b1 FM	110	/*
	111	* For a replace we can't just do the insert blindly.
	112	* Do a lookup first (read-only btrfs_search_slot), and return if xattr
	113	* doesn't exist. If it exists, fall down below to the insert/replace
	114	* path - we can't race with a concurrent xattr delete, because the VFS
	115	* locks the inode's i_mutex before calling setxattr or removexattr.
	116	*/
fa09200b	117	if (flags & XATTR_REPLACE) {
5955102c	118	ASSERT(inode_is_locked(inode));
f85b7379 DS	119	di = btrfs_lookup_xattr(NULL, root, path,
f85b7379 DS	120	btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
5cdf83ed	121	if (!di)
fa09200b	122	ret = -ENODATA;
5cdf83ed FM	123	else if (IS_ERR(di))
	124	ret = PTR_ERR(di);
	125	if (ret)
5103e947	126	goto out;
b3b4aa74	127	btrfs_release_path(path);
5f5bc6b1 FM	128	di = NULL;
5f5bc6b1 FM	129	}
4815053a	130
4a0cc7ca	131	ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
5f5bc6b1 FM	132	name, name_len, value, size);
5f5bc6b1 FM	133	if (ret == -EOVERFLOW) {
4815053a	134	/*
5f5bc6b1 FM	135	* We have an existing item in a leaf, split_leaf couldn't
	136	* expand it. That item might have or not a dir_item that
	137	* matches our target xattr, so lets check.
4815053a	138	*/
5f5bc6b1 FM	139	ret = 0;
5f5bc6b1 FM	140	btrfs_assert_tree_locked(path->nodes[0]);
2ff7e61e	141	di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
5f5bc6b1 FM	142	if (!di && !(flags & XATTR_REPLACE)) {
5f5bc6b1 FM	143	ret = -ENOSPC;
01e6deb2 LB	144	goto out;
01e6deb2 LB	145	}
5f5bc6b1 FM	146	} else if (ret == -EEXIST) {
5f5bc6b1 FM	147	ret = 0;
2ff7e61e	148	di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
5f5bc6b1 FM	149	ASSERT(di); /* logic error */
	150	} else if (ret) {
	151	goto out;
fa09200b	152	}
5103e947	153
5f5bc6b1	154	if (di && (flags & XATTR_CREATE)) {
ed3ee9f4	155	ret = -EEXIST;
5f5bc6b1 FM	156	goto out;
5f5bc6b1 FM	157	}
ed3ee9f4	158
5f5bc6b1	159	if (di) {
fa09200b	160	/*
5f5bc6b1 FM	161	* We're doing a replace, and it must be atomic, that is, at
	162	* any point in time we have either the old or the new xattr
	163	* value in the tree. We don't want readers (getxattr and
	164	* listxattrs) to miss a value, this is specially important
	165	* for ACLs.
fa09200b	166	*/
5f5bc6b1 FM	167	const int slot = path->slots[0];
	168	struct extent_buffer *leaf = path->nodes[0];
	169	const u16 old_data_len = btrfs_dir_data_len(leaf, di);
	170	const u32 item_size = btrfs_item_size_nr(leaf, slot);
	171	const u32 data_size = sizeof(*di) + name_len + size;
	172	struct btrfs_item *item;
	173	unsigned long data_ptr;
	174	char *ptr;
	175
	176	if (size > old_data_len) {
2ff7e61e	177	if (btrfs_leaf_free_space(fs_info, leaf) <
5f5bc6b1 FM	178	(size - old_data_len)) {
	179	ret = -ENOSPC;
	180	goto out;
	181	}
fa09200b	182	}
33268eaf	183
5f5bc6b1 FM	184	if (old_data_len + name_len + sizeof(*di) == item_size) {
	185	/* No other xattrs packed in the same leaf item. */
	186	if (size > old_data_len)
2ff7e61e	187	btrfs_extend_item(fs_info, path,
5f5bc6b1 FM	188	size - old_data_len);
5f5bc6b1 FM	189	else if (size < old_data_len)
2ff7e61e JM	190	btrfs_truncate_item(fs_info, path,
2ff7e61e JM	191	data_size, 1);
5f5bc6b1 FM	192	} else {
	193	/* There are other xattrs packed in the same item. */
	194	ret = btrfs_delete_one_dir_name(trans, root, path, di);
	195	if (ret)
	196	goto out;
2ff7e61e	197	btrfs_extend_item(fs_info, path, data_size);
5f5bc6b1	198	}
fa09200b	199
5f5bc6b1 FM	200	item = btrfs_item_nr(slot);
	201	ptr = btrfs_item_ptr(leaf, slot, char);
	202	ptr += btrfs_item_size(leaf, item) - data_size;
	203	di = (struct btrfs_dir_item *)ptr;
	204	btrfs_set_dir_data_len(leaf, di, size);
	205	data_ptr = ((unsigned long)(di + 1)) + name_len;
	206	write_extent_buffer(leaf, value, data_ptr, size);
	207	btrfs_mark_buffer_dirty(leaf);
	208	} else {
fa09200b	209	/*
5f5bc6b1 FM	210	* Insert, and we had space for the xattr, so path->slots[0] is
	211	* where our xattr dir_item is and btrfs_insert_xattr_item()
	212	* filled it.
fa09200b	213	*/
5103e947	214	}
f34f57a3 YZ	215	out:
	216	btrfs_free_path(path);
	217	return ret;
	218	}
	219
4815053a DS	220	/*
	221	* @value: "" makes the attribute to empty, NULL removes it
	222	*/
7852781d	223	int btrfs_setxattr(struct btrfs_trans_handle *trans,
f34f57a3 YZ	224	struct inode inode, const char name,
	225	const void *value, size_t size, int flags)
	226	{
	227	struct btrfs_root *root = BTRFS_I(inode)->root;
	228	int ret;
	229
e0d46f5c AG	230	if (btrfs_root_readonly(root))
	231	return -EROFS;
	232
f34f57a3 YZ	233	if (trans)
	234	return do_setxattr(trans, inode, name, value, size, flags);
	235
a22285a6 YZ	236	trans = btrfs_start_transaction(root, 2);
	237	if (IS_ERR(trans))
	238	return PTR_ERR(trans);
5103e947	239
f34f57a3 YZ	240	ret = do_setxattr(trans, inode, name, value, size, flags);
	241	if (ret)
	242	goto out;
	243
0c4d2d95	244	inode_inc_iversion(inode);
c2050a45	245	inode->i_ctime = current_time(inode);
e9976151	246	set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
f34f57a3 YZ	247	ret = btrfs_update_inode(trans, root, inode);
	248	BUG_ON(ret);
	249	out:
3a45bb20	250	btrfs_end_transaction(trans);
5103e947 JB	251	return ret;
	252	}
	253
	254	ssize_t btrfs_listxattr(struct dentry dentry, char buffer, size_t size)
	255	{
daac7ba6	256	struct btrfs_key key;
2b0143b5	257	struct inode *inode = d_inode(dentry);
5103e947 JB	258	struct btrfs_root *root = BTRFS_I(inode)->root;
5103e947 JB	259	struct btrfs_path *path;
daac7ba6	260	int ret = 0;
eaa47d86	261	size_t total_size = 0, size_left = size;
5103e947 JB	262
	263	/*
	264	* ok we want all objects associated with this id.
	265	* NOTE: we set key.offset = 0; because we want to start with the
	266	* first xattr that we find and walk forward
	267	*/
4a0cc7ca	268	key.objectid = btrfs_ino(BTRFS_I(inode));
962a298f	269	key.type = BTRFS_XATTR_ITEM_KEY;
5103e947 JB	270	key.offset = 0;
	271
	272	path = btrfs_alloc_path();
5103e947 JB	273	if (!path)
5103e947 JB	274	return -ENOMEM;
e4058b54	275	path->reada = READA_FORWARD;
5103e947	276
5103e947 JB	277	/* search for our xattrs */
	278	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	279	if (ret < 0)
	280	goto err;
2e6a0035	281
5103e947	282	while (1) {
daac7ba6 FM	283	struct extent_buffer *leaf;
	284	int slot;
	285	struct btrfs_dir_item *di;
	286	struct btrfs_key found_key;
	287	u32 item_size;
	288	u32 cur;
	289
5103e947	290	leaf = path->nodes[0];
5103e947 JB	291	slot = path->slots[0];
	292
	293	/* this is where we start walking through the path */
2e6a0035	294	if (slot >= btrfs_header_nritems(leaf)) {
5103e947 JB	295	/*
	296	* if we've reached the last slot in this leaf we need
	297	* to go to the next leaf and reset everything
	298	*/
2e6a0035 LZ	299	ret = btrfs_next_leaf(root, path);
	300	if (ret < 0)
	301	goto err;
	302	else if (ret > 0)
	303	break;
	304	continue;
5103e947	305	}
5103e947	306
5103e947 JB	307	btrfs_item_key_to_cpu(leaf, &found_key, slot);
	308
	309	/* check to make sure this item is what we want */
	310	if (found_key.objectid != key.objectid)
	311	break;
f1cd1f0b	312	if (found_key.type > BTRFS_XATTR_ITEM_KEY)
5103e947	313	break;
f1cd1f0b	314	if (found_key.type < BTRFS_XATTR_ITEM_KEY)
daac7ba6	315	goto next_item;
5103e947 JB	316
5103e947 JB	317	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
daac7ba6 FM	318	item_size = btrfs_item_size_nr(leaf, slot);
	319	cur = 0;
	320	while (cur < item_size) {
	321	u16 name_len = btrfs_dir_name_len(leaf, di);
	322	u16 data_len = btrfs_dir_data_len(leaf, di);
	323	u32 this_len = sizeof(*di) + name_len + data_len;
	324	unsigned long name_ptr = (unsigned long)(di + 1);
	325
daac7ba6 FM	326	total_size += name_len + 1;
	327	/*
	328	* We are just looking for how big our buffer needs to
	329	* be.
	330	*/
	331	if (!size)
	332	goto next;
5103e947	333
daac7ba6 FM	334	if (!buffer \|\| (name_len + 1) > size_left) {
	335	ret = -ERANGE;
	336	goto err;
	337	}
5103e947	338
daac7ba6 FM	339	read_extent_buffer(leaf, buffer, name_ptr, name_len);
daac7ba6 FM	340	buffer[name_len] = '\0';
eaa47d86	341
daac7ba6 FM	342	size_left -= name_len + 1;
daac7ba6 FM	343	buffer += name_len + 1;
2e6a0035	344	next:
daac7ba6 FM	345	cur += this_len;
	346	di = (struct btrfs_dir_item )((char )di + this_len);
	347	}
	348	next_item:
2e6a0035	349	path->slots[0]++;
5103e947 JB	350	}
	351	ret = total_size;
	352
	353	err:
5103e947 JB	354	btrfs_free_path(path);
	355
	356	return ret;
	357	}
	358
9172abbc	359	static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
b296821a AV	360	struct dentry unused, struct inode inode,
b296821a AV	361	const char name, void buffer, size_t size)
95819c05	362	{
9172abbc	363	name = xattr_full_name(handler, name);
7852781d	364	return btrfs_getxattr(inode, name, buffer, size);
69a32ac5 CM	365	}
69a32ac5 CM	366
9172abbc	367	static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
59301226 AV	368	struct dentry unused, struct inode inode,
	369	const char name, const void buffer,
	370	size_t size, int flags)
95819c05	371	{
9172abbc	372	name = xattr_full_name(handler, name);
7852781d	373	return btrfs_setxattr(NULL, inode, name, buffer, size, flags);
9172abbc	374	}
5103e947	375
9172abbc	376	static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
59301226	377	struct dentry unused, struct inode inode,
9172abbc AG	378	const char name, const void value,
	379	size_t size, int flags)
	380	{
	381	name = xattr_full_name(handler, name);
59301226	382	return btrfs_set_prop(inode, name, value, size, flags);
95819c05	383	}
5103e947	384
9172abbc AG	385	static const struct xattr_handler btrfs_security_xattr_handler = {
	386	.prefix = XATTR_SECURITY_PREFIX,
	387	.get = btrfs_xattr_handler_get,
	388	.set = btrfs_xattr_handler_set,
	389	};
	390
	391	static const struct xattr_handler btrfs_trusted_xattr_handler = {
	392	.prefix = XATTR_TRUSTED_PREFIX,
	393	.get = btrfs_xattr_handler_get,
	394	.set = btrfs_xattr_handler_set,
	395	};
	396
	397	static const struct xattr_handler btrfs_user_xattr_handler = {
	398	.prefix = XATTR_USER_PREFIX,
	399	.get = btrfs_xattr_handler_get,
	400	.set = btrfs_xattr_handler_set,
	401	};
	402
	403	static const struct xattr_handler btrfs_btrfs_xattr_handler = {
	404	.prefix = XATTR_BTRFS_PREFIX,
	405	.get = btrfs_xattr_handler_get,
	406	.set = btrfs_xattr_handler_set_prop,
	407	};
	408
	409	const struct xattr_handler *btrfs_xattr_handlers[] = {
	410	&btrfs_security_xattr_handler,
	411	#ifdef CONFIG_BTRFS_FS_POSIX_ACL
	412	&posix_acl_access_xattr_handler,
	413	&posix_acl_default_xattr_handler,
	414	#endif
	415	&btrfs_trusted_xattr_handler,
	416	&btrfs_user_xattr_handler,
	417	&btrfs_btrfs_xattr_handler,
	418	NULL,
	419	};
	420
48a3b636 ES	421	static int btrfs_initxattrs(struct inode *inode,
48a3b636 ES	422	const struct xattr xattr_array, void fs_info)
0279b4cd	423	{
9d8f13ba MZ	424	const struct xattr *xattr;
9d8f13ba MZ	425	struct btrfs_trans_handle *trans = fs_info;
827aa18e	426	unsigned int nofs_flag;
0279b4cd	427	char *name;
9d8f13ba	428	int err = 0;
0279b4cd	429
827aa18e FM	430	/*
	431	* We're holding a transaction handle, so use a NOFS memory allocation
	432	* context to avoid deadlock if reclaim happens.
	433	*/
	434	nofs_flag = memalloc_nofs_save();
9d8f13ba MZ	435	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
9d8f13ba MZ	436	name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
39a27ec1	437	strlen(xattr->name) + 1, GFP_KERNEL);
9d8f13ba MZ	438	if (!name) {
	439	err = -ENOMEM;
	440	break;
	441	}
0279b4cd	442	strcpy(name, XATTR_SECURITY_PREFIX);
9d8f13ba	443	strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
7852781d DS	444	err = btrfs_setxattr(trans, inode, name, xattr->value,
7852781d DS	445	xattr->value_len, 0);
0279b4cd	446	kfree(name);
9d8f13ba MZ	447	if (err < 0)
9d8f13ba MZ	448	break;
0279b4cd	449	}
827aa18e	450	memalloc_nofs_restore(nofs_flag);
0279b4cd JO	451	return err;
0279b4cd JO	452	}
9d8f13ba MZ	453
	454	int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
	455	struct inode inode, struct inode dir,
	456	const struct qstr *qstr)
	457	{
	458	return security_inode_init_security(inode, dir, qstr,
	459	&btrfs_initxattrs, trans);
	460	}