From 4dc3dd7aceb3d77d14ee798dbf3afde357e4bdb0 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 5 Jul 2014 16:28:35 -0400 Subject: ext4: fix unjournalled bg descriptor while initializing inode bitmap commit 61c219f5814277ecb71d64cb30297028d6665979 upstream. The first time that we allocate from an uninitialized inode allocation bitmap, if the block allocation bitmap is also uninitalized, we need to get write access to the block group descriptor before we start modifying the block group descriptor flags and updating the free block count, etc. Otherwise, there is the potential of a bad journal checksum (if journal checksums are enabled), and of the file system becoming inconsistent if we crash at exactly the wrong time. Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/ialloc.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'fs/ext4') diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 0ee59a6644e..64bb32f1790 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -851,6 +851,13 @@ got: goto out; } + BUFFER_TRACE(group_desc_bh, "get_write_access"); + err = ext4_journal_get_write_access(handle, group_desc_bh); + if (err) { + ext4_std_error(sb, err); + goto out; + } + /* We may have to initialize the block bitmap if it isn't already */ if (ext4_has_group_desc_csum(sb) && gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { @@ -887,13 +894,6 @@ got: } } - BUFFER_TRACE(group_desc_bh, "get_write_access"); - err = ext4_journal_get_write_access(handle, group_desc_bh); - if (err) { - ext4_std_error(sb, err); - goto out; - } - /* Update the relevant bg descriptor fields */ if (ext4_has_group_desc_csum(sb)) { int free; -- cgit v1.2.3-18-g5258