491 lines
12 KiB
C
491 lines
12 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 "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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static struct xattr_handler *btrfs_xattr_handler_map[] = {
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[BTRFS_XATTR_INDEX_USER] = &btrfs_xattr_user_handler,
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[BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS] = &btrfs_xattr_acl_access_handler,
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[BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &btrfs_xattr_acl_default_handler,
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[BTRFS_XATTR_INDEX_TRUSTED] = &btrfs_xattr_trusted_handler,
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[BTRFS_XATTR_INDEX_SECURITY] = &btrfs_xattr_security_handler,
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[BTRFS_XATTR_INDEX_SYSTEM] = &btrfs_xattr_system_handler,
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};
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struct xattr_handler *btrfs_xattr_handlers[] = {
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&btrfs_xattr_user_handler,
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&btrfs_xattr_acl_access_handler,
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&btrfs_xattr_acl_default_handler,
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&btrfs_xattr_trusted_handler,
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&btrfs_xattr_security_handler,
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&btrfs_xattr_system_handler,
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NULL,
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};
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/*
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* @param name - the xattr name
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* @return - the xattr_handler for the xattr, NULL if its not found
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*
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* use this with listxattr where we don't already know the type of xattr we
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* have
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*/
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static struct xattr_handler *find_btrfs_xattr_handler(struct extent_buffer *l,
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unsigned long name_ptr,
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u16 name_len)
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{
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struct xattr_handler *handler = NULL;
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int i = 0;
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for (handler = btrfs_xattr_handlers[i]; handler != NULL; i++,
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handler = btrfs_xattr_handlers[i]) {
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u16 prefix_len = strlen(handler->prefix);
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if (name_len < prefix_len)
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continue;
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if (memcmp_extent_buffer(l, handler->prefix, name_ptr,
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prefix_len) == 0)
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break;
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}
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return handler;
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}
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/*
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* @param name_index - the index for the xattr handler
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* @return the xattr_handler if we found it, NULL otherwise
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*
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* use this if we know the type of the xattr already
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*/
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static struct xattr_handler *btrfs_xattr_handler(int name_index)
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{
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struct xattr_handler *handler = NULL;
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if (name_index >= 0 &&
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name_index < ARRAY_SIZE(btrfs_xattr_handler_map))
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handler = btrfs_xattr_handler_map[name_index];
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return handler;
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}
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static inline char *get_name(const char *name, int name_index)
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{
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char *ret = NULL;
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struct xattr_handler *handler = btrfs_xattr_handler(name_index);
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int prefix_len;
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if (!handler)
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return ret;
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prefix_len = strlen(handler->prefix);
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ret = kmalloc(strlen(name) + prefix_len + 1, GFP_KERNEL);
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if (!ret)
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return ret;
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memcpy(ret, handler->prefix, prefix_len);
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memcpy(ret+prefix_len, name, strlen(name));
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ret[prefix_len + strlen(name)] = '\0';
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return ret;
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}
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size_t btrfs_xattr_generic_list(struct inode *inode, char *list,
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size_t list_size, const char *name,
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size_t name_len)
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{
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if (list && (name_len+1) <= list_size) {
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memcpy(list, name, name_len);
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list[name_len] = '\0';
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} else
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return -ERANGE;
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return name_len+1;
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}
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ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
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const char *attr_name, 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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struct xattr_handler *handler = btrfs_xattr_handler(name_index);
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int ret = 0;
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unsigned long data_ptr;
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char *name;
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if (!handler)
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return -EOPNOTSUPP;
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name = get_name(attr_name, name_index);
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if (!name)
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return -ENOMEM;
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path = btrfs_alloc_path();
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if (!path) {
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kfree(name);
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return -ENOMEM;
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}
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mutex_lock(&root->fs_info->fs_mutex);
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/* lookup the xattr by name */
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di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
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strlen(name), 0);
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if (!di || IS_ERR(di)) {
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ret = -ENODATA;
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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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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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mutex_unlock(&root->fs_info->fs_mutex);
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kfree(name);
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btrfs_free_path(path);
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return ret;
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}
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int btrfs_xattr_set(struct inode *inode, int name_index,
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const char *attr_name, const void *value, size_t size,
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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_trans_handle *trans;
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struct btrfs_path *path;
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struct xattr_handler *handler = btrfs_xattr_handler(name_index);
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char *name;
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int ret = 0, mod = 0;
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if (!handler)
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return -EOPNOTSUPP;
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name = get_name(attr_name, name_index);
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if (!name)
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return -ENOMEM;
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path = btrfs_alloc_path();
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if (!path) {
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kfree(name);
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return -ENOMEM;
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}
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mutex_lock(&root->fs_info->fs_mutex);
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trans = btrfs_start_transaction(root, 1);
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btrfs_set_trans_block_group(trans, inode);
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/* first lets see if we already have this xattr */
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di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name,
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strlen(name), -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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}
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/* ok we already have this xattr, lets remove it */
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if (di) {
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/* if we want create only exit */
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if (flags & XATTR_CREATE) {
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ret = -EEXIST;
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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(root, path);
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/* if we don't have a value then we are removing the xattr */
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if (!value) {
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mod = 1;
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goto out;
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}
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} else if (flags & XATTR_REPLACE) {
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/* we couldn't find the attr to replace, so error out */
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ret = -ENODATA;
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goto out;
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}
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/* ok we have to create a completely new xattr */
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ret = btrfs_insert_xattr_item(trans, root, name, strlen(name),
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value, size, inode->i_ino);
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if (ret)
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goto out;
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mod = 1;
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out:
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if (mod) {
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inode->i_ctime = CURRENT_TIME;
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ret = btrfs_update_inode(trans, root, inode);
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}
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btrfs_end_transaction(trans, root);
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mutex_unlock(&root->fs_info->fs_mutex);
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kfree(name);
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btrfs_free_path(path);
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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 btrfs_item *item;
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struct extent_buffer *leaf;
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struct btrfs_dir_item *di;
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struct xattr_handler *handler;
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int ret = 0, slot, advance;
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size_t total_size = 0, size_left = size, written;
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unsigned long name_ptr;
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char *name;
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u32 nritems;
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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 = inode->i_ino;
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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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mutex_lock(&root->fs_info->fs_mutex);
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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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ret = 0;
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advance = 0;
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while (1) {
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leaf = path->nodes[0];
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nritems = btrfs_header_nritems(leaf);
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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 (advance || slot >= nritems) {
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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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if (slot >= nritems-1) {
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ret = btrfs_next_leaf(root, path);
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if (ret)
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break;
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leaf = path->nodes[0];
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nritems = btrfs_header_nritems(leaf);
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slot = path->slots[0];
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} else {
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/*
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* just walking through the slots on this leaf
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*/
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slot++;
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path->slots[0]++;
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}
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}
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advance = 1;
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item = btrfs_item_nr(leaf, slot);
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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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total_size += btrfs_dir_name_len(leaf, di)+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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continue;
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/* find our handler for this xattr */
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name_ptr = (unsigned long)(di + 1);
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handler = find_btrfs_xattr_handler(leaf, name_ptr,
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btrfs_dir_name_len(leaf, di));
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if (!handler) {
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printk(KERN_ERR "btrfs: unsupported xattr found\n");
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continue;
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}
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name = kmalloc(btrfs_dir_name_len(leaf, di), GFP_KERNEL);
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read_extent_buffer(leaf, name, name_ptr,
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btrfs_dir_name_len(leaf, di));
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/* call the list function associated with this xattr */
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written = handler->list(inode, buffer, size_left, name,
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btrfs_dir_name_len(leaf, di));
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kfree(name);
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if (written < 0) {
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ret = -ERANGE;
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break;
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}
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size_left -= written;
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buffer += written;
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}
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ret = total_size;
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err:
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mutex_unlock(&root->fs_info->fs_mutex);
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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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* delete all the xattrs associated with the inode. fs_mutex should be
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* held when we come into here
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*/
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int btrfs_delete_xattrs(struct btrfs_trans_handle *trans,
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struct btrfs_root *root, struct inode *inode)
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{
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struct btrfs_path *path;
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struct btrfs_key key, found_key;
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struct btrfs_item *item;
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struct extent_buffer *leaf;
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int ret;
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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 = -1;
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key.objectid = inode->i_ino;
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btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
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key.offset = (u64)-1;
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while(1) {
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/* look for our next xattr */
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ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
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if (ret < 0)
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goto out;
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BUG_ON(ret == 0);
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if (path->slots[0] == 0)
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break;
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path->slots[0]--;
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leaf = path->nodes[0];
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item = btrfs_item_nr(leaf, path->slots[0]);
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btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
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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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ret = btrfs_del_item(trans, root, path);
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BUG_ON(ret);
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btrfs_release_path(root, path);
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}
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ret = 0;
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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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* Handler functions
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*/
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#define BTRFS_XATTR_SETGET_FUNCS(name, index) \
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static int btrfs_xattr_##name##_get(struct inode *inode, \
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const char *name, void *value, \
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size_t size) \
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{ \
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if (*name == '\0') \
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return -EINVAL; \
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return btrfs_xattr_get(inode, index, name, value, size); \
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} \
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static int btrfs_xattr_##name##_set(struct inode *inode, \
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const char *name, const void *value,\
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size_t size, int flags) \
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{ \
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if (*name == '\0') \
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return -EINVAL; \
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return btrfs_xattr_set(inode, index, name, value, size, flags); \
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}
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BTRFS_XATTR_SETGET_FUNCS(security, BTRFS_XATTR_INDEX_SECURITY);
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BTRFS_XATTR_SETGET_FUNCS(system, BTRFS_XATTR_INDEX_SYSTEM);
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BTRFS_XATTR_SETGET_FUNCS(user, BTRFS_XATTR_INDEX_USER);
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BTRFS_XATTR_SETGET_FUNCS(trusted, BTRFS_XATTR_INDEX_TRUSTED);
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struct xattr_handler btrfs_xattr_security_handler = {
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.prefix = XATTR_SECURITY_PREFIX,
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.list = btrfs_xattr_generic_list,
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.get = btrfs_xattr_security_get,
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.set = btrfs_xattr_security_set,
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};
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struct xattr_handler btrfs_xattr_system_handler = {
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.prefix = XATTR_SYSTEM_PREFIX,
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.list = btrfs_xattr_generic_list,
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.get = btrfs_xattr_system_get,
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.set = btrfs_xattr_system_set,
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};
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struct xattr_handler btrfs_xattr_user_handler = {
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.prefix = XATTR_USER_PREFIX,
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.list = btrfs_xattr_generic_list,
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.get = btrfs_xattr_user_get,
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.set = btrfs_xattr_user_set,
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};
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struct xattr_handler btrfs_xattr_trusted_handler = {
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.prefix = XATTR_TRUSTED_PREFIX,
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.list = btrfs_xattr_generic_list,
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.get = btrfs_xattr_trusted_get,
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.set = btrfs_xattr_trusted_set,
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};
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