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Btrfs: check size of inode backref before adding hardlink

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For every hardlink in btrfs, there is a corresponding inode back
reference. All inode back references for hardlinks in a given
directory are stored in single b-tree item. The size of b-tree item
is limited by the size of b-tree leaf, so we can only create limited
number of hardlinks to a given file in a directory.

The original code lacks of the check, it oops if the number of
hardlinks goes over the limit. This patch fixes the issue by adding
check to btrfs_link and btrfs_rename.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Yan, Zheng 2009-09-24 09:17:31 -04:00 committed by Chris Mason
parent 11ef160fda
commit a571952143
3 changed files with 37 additions and 24 deletions
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6
fs/btrfs/ctree.c
View File

@ -2853,6 +2853,12 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
int split;
int num_doubles = 0;
l = path->nodes[0];
slot = path->slots[0];
if (extend && data_size + btrfs_item_size_nr(l, slot) +
sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root))
return -EOVERFLOW;
/* first try to make some room by pushing left and right */
if (data_size && ins_key->type != BTRFS_DIR_ITEM_KEY) {
wret = push_leaf_right(trans, root, path, data_size, 0);

2
fs/btrfs/inode-item.c
View File

@ -149,6 +149,8 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
ptr = (unsigned long)(ref + 1);
ret = 0;
} else if (ret < 0) {
if (ret == -EOVERFLOW)
ret = -EMLINK;
goto out;
} else {
ref = btrfs_item_ptr(path->nodes[0], path->slots[0],

53
fs/btrfs/inode.c
View File

@ -4133,18 +4133,16 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
err = btrfs_add_nondir(trans, dentry, inode, 1, index);
if (err)
drop_inode = 1;
btrfs_update_inode_block_group(trans, dir);
err = btrfs_update_inode(trans, root, inode);
if (err)
if (err) {
drop_inode = 1;
} else {
btrfs_update_inode_block_group(trans, dir);
err = btrfs_update_inode(trans, root, inode);
BUG_ON(err);
btrfs_log_new_name(trans, inode, NULL, dentry->d_parent);
}
nr = trans->blocks_used;
btrfs_log_new_name(trans, inode, NULL, dentry->d_parent);
btrfs_end_transaction_throttle(trans, root);
fail:
if (drop_inode) {
@ -5087,23 +5085,26 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
down_read(&root->fs_info->subvol_sem);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, new_dir);
if (dest != root)
btrfs_record_root_in_trans(trans, dest);
/*
* make sure the inode gets flushed if it is replacing
* something.
*/
if (new_inode && new_inode->i_size &&
old_inode && S_ISREG(old_inode->i_mode)) {
btrfs_add_ordered_operation(trans, root, old_inode);
}
ret = btrfs_set_inode_index(new_dir, &index);
if (ret)
goto out_fail;
if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
if (unlikely(old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
/* force full log commit if subvolume involved. */
root->fs_info->last_trans_log_full_commit = trans->transid;
} else {
ret = btrfs_insert_inode_ref(trans, dest,
new_dentry->d_name.name,
new_dentry->d_name.len,
old_inode->i_ino,
new_dir->i_ino, index);
if (ret)
goto out_fail;
/*
* this is an ugly little race, but the rename is required
* to make sure that if we crash, the inode is either at the
@ -5113,8 +5114,14 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
*/
btrfs_pin_log_trans(root);
}
btrfs_set_trans_block_group(trans, new_dir);
/*
* make sure the inode gets flushed if it is replacing
* something.
*/
if (new_inode && new_inode->i_size &&
old_inode && S_ISREG(old_inode->i_mode)) {
btrfs_add_ordered_operation(trans, root, old_inode);
}
old_dir->i_ctime = old_dir->i_mtime = ctime;
new_dir->i_ctime = new_dir->i_mtime = ctime;
@ -5159,12 +5166,10 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
BUG_ON(ret);
}
}
ret = btrfs_set_inode_index(new_dir, &index);
BUG_ON(ret);
ret = btrfs_add_link(trans, new_dir, old_inode,
new_dentry->d_name.name,
new_dentry->d_name.len, 1, index);
new_dentry->d_name.len, 0, index);
BUG_ON(ret);
if (old_inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) {
@ -5172,7 +5177,7 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
new_dentry->d_parent);
btrfs_end_log_trans(root);
}
out_fail:
btrfs_end_transaction_throttle(trans, root);
if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)