[mirror_ubuntu-hirsute-kernel.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);
		clear_bit(BTRFS_INODE_NO_XATTRS, &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, BTRFS_I(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, BTRFS_I(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);
f2f121ab	216	if (!ret) {
3763771c FM	217	set_bit(BTRFS_INODE_COPY_EVERYTHING,
3763771c FM	218	&BTRFS_I(inode)->runtime_flags);
f2f121ab FM	219	clear_bit(BTRFS_INODE_NO_XATTRS, &BTRFS_I(inode)->runtime_flags);
f2f121ab FM	220	}
f34f57a3 YZ	221	return ret;
	222	}
	223
4815053a DS	224	/*
	225	* @value: "" makes the attribute to empty, NULL removes it
	226	*/
e3de9b15	227	int btrfs_setxattr_trans(struct inode inode, const char name,
cac237ae	228	const void *value, size_t size, int flags)
f34f57a3 YZ	229	{
f34f57a3 YZ	230	struct btrfs_root *root = BTRFS_I(inode)->root;
e3de9b15	231	struct btrfs_trans_handle *trans;
f34f57a3 YZ	232	int ret;
f34f57a3 YZ	233
a22285a6 YZ	234	trans = btrfs_start_transaction(root, 2);
	235	if (IS_ERR(trans))
	236	return PTR_ERR(trans);
5103e947	237
2d74fa3e	238	ret = btrfs_setxattr(trans, inode, name, value, size, flags);
f34f57a3 YZ	239	if (ret)
	240	goto out;
	241
0c4d2d95	242	inode_inc_iversion(inode);
c2050a45	243	inode->i_ctime = current_time(inode);
9a56fcd1	244	ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
f34f57a3 YZ	245	BUG_ON(ret);
f34f57a3 YZ	246	out:
3a45bb20	247	btrfs_end_transaction(trans);
5103e947 JB	248	return ret;
	249	}
	250
	251	ssize_t btrfs_listxattr(struct dentry dentry, char buffer, size_t size)
	252	{
daac7ba6	253	struct btrfs_key key;
2b0143b5	254	struct inode *inode = d_inode(dentry);
5103e947 JB	255	struct btrfs_root *root = BTRFS_I(inode)->root;
5103e947 JB	256	struct btrfs_path *path;
daac7ba6	257	int ret = 0;
eaa47d86	258	size_t total_size = 0, size_left = size;
5103e947 JB	259
	260	/*
	261	* ok we want all objects associated with this id.
	262	* NOTE: we set key.offset = 0; because we want to start with the
	263	* first xattr that we find and walk forward
	264	*/
4a0cc7ca	265	key.objectid = btrfs_ino(BTRFS_I(inode));
962a298f	266	key.type = BTRFS_XATTR_ITEM_KEY;
5103e947 JB	267	key.offset = 0;
	268
	269	path = btrfs_alloc_path();
5103e947 JB	270	if (!path)
5103e947 JB	271	return -ENOMEM;
e4058b54	272	path->reada = READA_FORWARD;
5103e947	273
5103e947 JB	274	/* search for our xattrs */
	275	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	276	if (ret < 0)
	277	goto err;
2e6a0035	278
5103e947	279	while (1) {
daac7ba6 FM	280	struct extent_buffer *leaf;
	281	int slot;
	282	struct btrfs_dir_item *di;
	283	struct btrfs_key found_key;
	284	u32 item_size;
	285	u32 cur;
	286
5103e947	287	leaf = path->nodes[0];
5103e947 JB	288	slot = path->slots[0];
	289
	290	/* this is where we start walking through the path */
2e6a0035	291	if (slot >= btrfs_header_nritems(leaf)) {
5103e947 JB	292	/*
	293	* if we've reached the last slot in this leaf we need
	294	* to go to the next leaf and reset everything
	295	*/
2e6a0035 LZ	296	ret = btrfs_next_leaf(root, path);
	297	if (ret < 0)
	298	goto err;
	299	else if (ret > 0)
	300	break;
	301	continue;
5103e947	302	}
5103e947	303
5103e947 JB	304	btrfs_item_key_to_cpu(leaf, &found_key, slot);
	305
	306	/* check to make sure this item is what we want */
	307	if (found_key.objectid != key.objectid)
	308	break;
f1cd1f0b	309	if (found_key.type > BTRFS_XATTR_ITEM_KEY)
5103e947	310	break;
f1cd1f0b	311	if (found_key.type < BTRFS_XATTR_ITEM_KEY)
daac7ba6	312	goto next_item;
5103e947 JB	313
5103e947 JB	314	di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
daac7ba6 FM	315	item_size = btrfs_item_size_nr(leaf, slot);
	316	cur = 0;
	317	while (cur < item_size) {
	318	u16 name_len = btrfs_dir_name_len(leaf, di);
	319	u16 data_len = btrfs_dir_data_len(leaf, di);
	320	u32 this_len = sizeof(*di) + name_len + data_len;
	321	unsigned long name_ptr = (unsigned long)(di + 1);
	322
daac7ba6 FM	323	total_size += name_len + 1;
	324	/*
	325	* We are just looking for how big our buffer needs to
	326	* be.
	327	*/
	328	if (!size)
	329	goto next;
5103e947	330
daac7ba6 FM	331	if (!buffer \|\| (name_len + 1) > size_left) {
	332	ret = -ERANGE;
	333	goto err;
	334	}
5103e947	335
daac7ba6 FM	336	read_extent_buffer(leaf, buffer, name_ptr, name_len);
daac7ba6 FM	337	buffer[name_len] = '\0';
eaa47d86	338
daac7ba6 FM	339	size_left -= name_len + 1;
daac7ba6 FM	340	buffer += name_len + 1;
2e6a0035	341	next:
daac7ba6 FM	342	cur += this_len;
	343	di = (struct btrfs_dir_item )((char )di + this_len);
	344	}
	345	next_item:
2e6a0035	346	path->slots[0]++;
5103e947 JB	347	}
	348	ret = total_size;
	349
	350	err:
5103e947 JB	351	btrfs_free_path(path);
	352
	353	return ret;
	354	}
	355
9172abbc	356	static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
b296821a AV	357	struct dentry unused, struct inode inode,
b296821a AV	358	const char name, void buffer, size_t size)
95819c05	359	{
9172abbc	360	name = xattr_full_name(handler, name);
7852781d	361	return btrfs_getxattr(inode, name, buffer, size);
69a32ac5 CM	362	}
69a32ac5 CM	363
9172abbc	364	static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
59301226 AV	365	struct dentry unused, struct inode inode,
	366	const char name, const void buffer,
	367	size_t size, int flags)
95819c05	368	{
9172abbc	369	name = xattr_full_name(handler, name);
e3de9b15	370	return btrfs_setxattr_trans(inode, name, buffer, size, flags);
9172abbc	371	}
5103e947	372
9172abbc	373	static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
59301226	374	struct dentry unused, struct inode inode,
9172abbc AG	375	const char name, const void value,
	376	size_t size, int flags)
	377	{
f22125e5	378	int ret;
b3f6a4be AJ	379	struct btrfs_trans_handle *trans;
b3f6a4be AJ	380	struct btrfs_root *root = BTRFS_I(inode)->root;
f22125e5	381
9172abbc	382	name = xattr_full_name(handler, name);
f22125e5 AJ	383	ret = btrfs_validate_prop(name, value, size);
	384	if (ret)
	385	return ret;
b3f6a4be AJ	386
	387	trans = btrfs_start_transaction(root, 2);
	388	if (IS_ERR(trans))
	389	return PTR_ERR(trans);
	390
	391	ret = btrfs_set_prop(trans, inode, name, value, size, flags);
	392	if (!ret) {
	393	inode_inc_iversion(inode);
	394	inode->i_ctime = current_time(inode);
9a56fcd1	395	ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
b3f6a4be AJ	396	BUG_ON(ret);
	397	}
	398
	399	btrfs_end_transaction(trans);
	400
	401	return ret;
95819c05	402	}
5103e947	403
9172abbc AG	404	static const struct xattr_handler btrfs_security_xattr_handler = {
	405	.prefix = XATTR_SECURITY_PREFIX,
	406	.get = btrfs_xattr_handler_get,
	407	.set = btrfs_xattr_handler_set,
	408	};
	409
	410	static const struct xattr_handler btrfs_trusted_xattr_handler = {
	411	.prefix = XATTR_TRUSTED_PREFIX,
	412	.get = btrfs_xattr_handler_get,
	413	.set = btrfs_xattr_handler_set,
	414	};
	415
	416	static const struct xattr_handler btrfs_user_xattr_handler = {
	417	.prefix = XATTR_USER_PREFIX,
	418	.get = btrfs_xattr_handler_get,
	419	.set = btrfs_xattr_handler_set,
	420	};
	421
	422	static const struct xattr_handler btrfs_btrfs_xattr_handler = {
	423	.prefix = XATTR_BTRFS_PREFIX,
	424	.get = btrfs_xattr_handler_get,
	425	.set = btrfs_xattr_handler_set_prop,
	426	};
	427
	428	const struct xattr_handler *btrfs_xattr_handlers[] = {
	429	&btrfs_security_xattr_handler,
	430	#ifdef CONFIG_BTRFS_FS_POSIX_ACL
	431	&posix_acl_access_xattr_handler,
	432	&posix_acl_default_xattr_handler,
	433	#endif
	434	&btrfs_trusted_xattr_handler,
	435	&btrfs_user_xattr_handler,
	436	&btrfs_btrfs_xattr_handler,
	437	NULL,
	438	};
	439
48a3b636	440	static int btrfs_initxattrs(struct inode *inode,
419a6f30	441	const struct xattr xattr_array, void fs_private)
0279b4cd	442	{
419a6f30	443	struct btrfs_trans_handle *trans = fs_private;
9d8f13ba	444	const struct xattr *xattr;
827aa18e	445	unsigned int nofs_flag;
0279b4cd	446	char *name;
9d8f13ba	447	int err = 0;
0279b4cd	448
827aa18e FM	449	/*
	450	* We're holding a transaction handle, so use a NOFS memory allocation
	451	* context to avoid deadlock if reclaim happens.
	452	*/
	453	nofs_flag = memalloc_nofs_save();
9d8f13ba MZ	454	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
9d8f13ba MZ	455	name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
39a27ec1	456	strlen(xattr->name) + 1, GFP_KERNEL);
9d8f13ba MZ	457	if (!name) {
	458	err = -ENOMEM;
	459	break;
	460	}
0279b4cd	461	strcpy(name, XATTR_SECURITY_PREFIX);
9d8f13ba	462	strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
04e6863b AJ	463	err = btrfs_setxattr(trans, inode, name, xattr->value,
04e6863b AJ	464	xattr->value_len, 0);
0279b4cd	465	kfree(name);
9d8f13ba MZ	466	if (err < 0)
9d8f13ba MZ	467	break;
0279b4cd	468	}
827aa18e	469	memalloc_nofs_restore(nofs_flag);
0279b4cd JO	470	return err;
0279b4cd JO	471	}
9d8f13ba MZ	472
	473	int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
	474	struct inode inode, struct inode dir,
	475	const struct qstr *qstr)
	476	{
	477	return security_inode_init_security(inode, dir, qstr,
	478	&btrfs_initxattrs, trans);
	479	}