mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 21:54:06 +08:00
0c4d2d95d0
We've been keeping around the inode sequence number in hopes that somebody would use it, but nobody uses it and people actually use i_version which serves the same purpose, so use i_version where we used the incore inode's sequence number and that way the sequence is updated properly across the board, and not just in file write. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
431 lines
11 KiB
C
431 lines
11 KiB
C
/*
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* Copyright (C) 2007 Red Hat. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/rwsem.h>
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#include <linux/xattr.h>
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#include <linux/security.h>
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#include "ctree.h"
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#include "btrfs_inode.h"
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#include "transaction.h"
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#include "xattr.h"
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#include "disk-io.h"
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ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct btrfs_dir_item *di;
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struct btrfs_root *root = BTRFS_I(inode)->root;
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struct btrfs_path *path;
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struct extent_buffer *leaf;
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int ret = 0;
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unsigned long data_ptr;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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/* lookup the xattr by name */
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di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(inode), name,
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strlen(name), 0);
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if (!di) {
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ret = -ENODATA;
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goto out;
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} else if (IS_ERR(di)) {
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ret = PTR_ERR(di);
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goto out;
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}
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leaf = path->nodes[0];
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/* if size is 0, that means we want the size of the attr */
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if (!size) {
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ret = btrfs_dir_data_len(leaf, di);
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goto out;
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}
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/* now get the data out of our dir_item */
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if (btrfs_dir_data_len(leaf, di) > size) {
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ret = -ERANGE;
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goto out;
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}
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/*
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* The way things are packed into the leaf is like this
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* |struct btrfs_dir_item|name|data|
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* where name is the xattr name, so security.foo, and data is the
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* content of the xattr. data_ptr points to the location in memory
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* where the data starts in the in memory leaf
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*/
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data_ptr = (unsigned long)((char *)(di + 1) +
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btrfs_dir_name_len(leaf, di));
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read_extent_buffer(leaf, buffer, data_ptr,
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btrfs_dir_data_len(leaf, di));
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ret = btrfs_dir_data_len(leaf, di);
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out:
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btrfs_free_path(path);
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return ret;
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}
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static int do_setxattr(struct btrfs_trans_handle *trans,
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struct inode *inode, const char *name,
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const void *value, size_t size, int flags)
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{
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struct btrfs_dir_item *di;
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struct btrfs_root *root = BTRFS_I(inode)->root;
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struct btrfs_path *path;
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size_t name_len = strlen(name);
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int ret = 0;
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if (name_len + size > BTRFS_MAX_XATTR_SIZE(root))
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return -ENOSPC;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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if (flags & XATTR_REPLACE) {
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di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name,
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name_len, -1);
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if (IS_ERR(di)) {
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ret = PTR_ERR(di);
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goto out;
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} else if (!di) {
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ret = -ENODATA;
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goto out;
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}
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ret = btrfs_delete_one_dir_name(trans, root, path, di);
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if (ret)
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goto out;
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btrfs_release_path(path);
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/*
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* remove the attribute
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*/
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if (!value)
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goto out;
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}
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again:
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ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode),
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name, name_len, value, size);
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/*
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* If we're setting an xattr to a new value but the new value is say
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* exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
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* back from split_leaf. This is because it thinks we'll be extending
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* the existing item size, but we're asking for enough space to add the
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* item itself. So if we get EOVERFLOW just set ret to EEXIST and let
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* the rest of the function figure it out.
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*/
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if (ret == -EOVERFLOW)
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ret = -EEXIST;
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if (ret == -EEXIST) {
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if (flags & XATTR_CREATE)
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goto out;
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/*
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* We can't use the path we already have since we won't have the
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* proper locking for a delete, so release the path and
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* re-lookup to delete the thing.
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*/
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btrfs_release_path(path);
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di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode),
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name, name_len, -1);
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if (IS_ERR(di)) {
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ret = PTR_ERR(di);
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goto out;
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} else if (!di) {
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/* Shouldn't happen but just in case... */
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btrfs_release_path(path);
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goto again;
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}
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ret = btrfs_delete_one_dir_name(trans, root, path, di);
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if (ret)
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goto out;
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/*
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* We have a value to set, so go back and try to insert it now.
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*/
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if (value) {
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btrfs_release_path(path);
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goto again;
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}
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}
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out:
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btrfs_free_path(path);
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return ret;
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}
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/*
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* @value: "" makes the attribute to empty, NULL removes it
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*/
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int __btrfs_setxattr(struct btrfs_trans_handle *trans,
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struct inode *inode, const char *name,
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const void *value, size_t size, int flags)
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{
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struct btrfs_root *root = BTRFS_I(inode)->root;
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int ret;
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if (trans)
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return do_setxattr(trans, inode, name, value, size, flags);
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trans = btrfs_start_transaction(root, 2);
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if (IS_ERR(trans))
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return PTR_ERR(trans);
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ret = do_setxattr(trans, inode, name, value, size, flags);
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if (ret)
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goto out;
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inode_inc_iversion(inode);
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inode->i_ctime = CURRENT_TIME;
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ret = btrfs_update_inode(trans, root, inode);
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BUG_ON(ret);
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out:
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btrfs_end_transaction(trans, root);
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return ret;
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}
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ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
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{
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struct btrfs_key key, found_key;
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struct inode *inode = dentry->d_inode;
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struct btrfs_root *root = BTRFS_I(inode)->root;
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struct btrfs_path *path;
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struct extent_buffer *leaf;
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struct btrfs_dir_item *di;
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int ret = 0, slot;
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size_t total_size = 0, size_left = size;
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unsigned long name_ptr;
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size_t name_len;
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/*
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* ok we want all objects associated with this id.
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* NOTE: we set key.offset = 0; because we want to start with the
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* first xattr that we find and walk forward
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*/
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key.objectid = btrfs_ino(inode);
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btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
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key.offset = 0;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->reada = 2;
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/* search for our xattrs */
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ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
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if (ret < 0)
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goto err;
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while (1) {
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leaf = path->nodes[0];
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slot = path->slots[0];
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/* this is where we start walking through the path */
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if (slot >= btrfs_header_nritems(leaf)) {
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/*
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* if we've reached the last slot in this leaf we need
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* to go to the next leaf and reset everything
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*/
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ret = btrfs_next_leaf(root, path);
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if (ret < 0)
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goto err;
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else if (ret > 0)
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break;
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continue;
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}
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btrfs_item_key_to_cpu(leaf, &found_key, slot);
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/* check to make sure this item is what we want */
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if (found_key.objectid != key.objectid)
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break;
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if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
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break;
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di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
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if (verify_dir_item(root, leaf, di))
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continue;
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name_len = btrfs_dir_name_len(leaf, di);
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total_size += name_len + 1;
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/* we are just looking for how big our buffer needs to be */
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if (!size)
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goto next;
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if (!buffer || (name_len + 1) > size_left) {
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ret = -ERANGE;
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goto err;
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}
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name_ptr = (unsigned long)(di + 1);
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read_extent_buffer(leaf, buffer, name_ptr, name_len);
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buffer[name_len] = '\0';
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size_left -= name_len + 1;
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buffer += name_len + 1;
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next:
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path->slots[0]++;
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}
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ret = total_size;
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err:
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btrfs_free_path(path);
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return ret;
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}
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/*
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* List of handlers for synthetic system.* attributes. All real ondisk
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* attributes are handled directly.
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*/
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const struct xattr_handler *btrfs_xattr_handlers[] = {
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#ifdef CONFIG_BTRFS_FS_POSIX_ACL
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&btrfs_xattr_acl_access_handler,
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&btrfs_xattr_acl_default_handler,
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#endif
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NULL,
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};
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/*
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* Check if the attribute is in a supported namespace.
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*
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* This applied after the check for the synthetic attributes in the system
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* namespace.
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*/
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static bool btrfs_is_valid_xattr(const char *name)
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{
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return !strncmp(name, XATTR_SECURITY_PREFIX,
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XATTR_SECURITY_PREFIX_LEN) ||
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!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
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!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
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!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
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}
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ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
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void *buffer, size_t size)
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{
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/*
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* If this is a request for a synthetic attribute in the system.*
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* namespace use the generic infrastructure to resolve a handler
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* for it via sb->s_xattr.
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*/
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if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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return generic_getxattr(dentry, name, buffer, size);
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if (!btrfs_is_valid_xattr(name))
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return -EOPNOTSUPP;
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return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
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}
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int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
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size_t size, int flags)
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{
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struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
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/*
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* The permission on security.* and system.* is not checked
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* in permission().
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*/
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if (btrfs_root_readonly(root))
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return -EROFS;
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/*
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* If this is a request for a synthetic attribute in the system.*
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* namespace use the generic infrastructure to resolve a handler
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* for it via sb->s_xattr.
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*/
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if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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return generic_setxattr(dentry, name, value, size, flags);
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if (!btrfs_is_valid_xattr(name))
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return -EOPNOTSUPP;
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if (size == 0)
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value = ""; /* empty EA, do not remove */
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return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size,
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flags);
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}
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int btrfs_removexattr(struct dentry *dentry, const char *name)
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{
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struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
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/*
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* The permission on security.* and system.* is not checked
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* in permission().
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*/
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if (btrfs_root_readonly(root))
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return -EROFS;
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/*
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* If this is a request for a synthetic attribute in the system.*
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* namespace use the generic infrastructure to resolve a handler
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* for it via sb->s_xattr.
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*/
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if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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return generic_removexattr(dentry, name);
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if (!btrfs_is_valid_xattr(name))
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return -EOPNOTSUPP;
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return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0,
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XATTR_REPLACE);
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}
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int btrfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
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void *fs_info)
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{
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const struct xattr *xattr;
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struct btrfs_trans_handle *trans = fs_info;
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char *name;
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int err = 0;
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for (xattr = xattr_array; xattr->name != NULL; xattr++) {
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name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
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strlen(xattr->name) + 1, GFP_NOFS);
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if (!name) {
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err = -ENOMEM;
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break;
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}
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strcpy(name, XATTR_SECURITY_PREFIX);
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strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
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err = __btrfs_setxattr(trans, inode, name,
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xattr->value, xattr->value_len, 0);
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kfree(name);
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if (err < 0)
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break;
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}
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return err;
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}
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int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
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struct inode *inode, struct inode *dir,
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const struct qstr *qstr)
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{
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return security_inode_init_security(inode, dir, qstr,
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&btrfs_initxattrs, trans);
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}
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