From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josef Bacik Subject: [PATCH] Btrfs: fail to mount if we have problems reading the block groups Date: Fri, 19 Mar 2010 16:49:55 -0400 Message-ID: <20100319204955.GD2314@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: linux-btrfs@vger.kernel.org Return-path: List-ID: We don't actually check the return value of btrfs_read_block_groups, so we can possibly succeed to mount, but then fail to say read the superblock xattr for selinux which will cause the vfs code to deactivate the super. This is a problem because in find_free_extent we just assume that we will find the right space_info for the allocation we want. But if we failed to read the block groups, we won't have setup any space_info's, and we'll hit a NULL pointer deref in find_free_extent. This patch fixes that problem by checking the return value of btrfs_read_block_groups, and failing out properly. I've also added a check in find_free_extent so if for some reason we don't find an appropriate space_info, we just return -ENOSPC. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/disk-io.c | 11 ++++++++--- fs/btrfs/extent-tree.c | 5 ++++- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index dfe7a95..6632e5c 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1921,7 +1921,11 @@ struct btrfs_root *open_ctree(struct super_block *sb, csum_root->track_dirty = 1; - btrfs_read_block_groups(extent_root); + ret = btrfs_read_block_groups(extent_root); + if (ret) { + printk(KERN_ERR "Failed to read block groups: %d\n", ret); + goto fail_block_groups; + } fs_info->generation = generation; fs_info->last_trans_committed = generation; @@ -1931,7 +1935,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root, "btrfs-cleaner"); if (IS_ERR(fs_info->cleaner_kthread)) - goto fail_csum_root; + goto fail_block_groups; fs_info->transaction_kthread = kthread_run(transaction_kthread, tree_root, @@ -2019,7 +2023,8 @@ fail_cleaner: filemap_write_and_wait(fs_info->btree_inode->i_mapping); invalidate_inode_pages2(fs_info->btree_inode->i_mapping); -fail_csum_root: +fail_block_groups: + btrfs_free_block_groups(fs_info); free_extent_buffer(csum_root->node); free_extent_buffer(csum_root->commit_root); fail_dev_root: diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 1860969..ec84862 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4179,6 +4179,10 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans, ins->offset = 0; space_info = __find_space_info(root->fs_info, data); + if (!space_info) { + printk(KERN_ERR "No space info for %d\n", data); + return -ENOSPC; + } if (orig_root->ref_cows || empty_size) allowed_chunk_alloc = 1; @@ -7378,7 +7382,6 @@ static int find_first_block_group(struct btrfs_root *root, } path->slots[0]++; } - ret = -ENOENT; out: return ret; } -- 1.6.6