From c7d8ee24e397b55ee5f7dd602397d16340c23e25 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 5 Jul 2014 16:28:35 -0400 Subject: [PATCH] ext4: fix unjournalled bg descriptor while initializing inode bitmap 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 Cc: stable@vger.kernel.org --- fs/ext4/ialloc.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index a87455df38bca..0840bf321cdb5 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -874,6 +874,13 @@ 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)) { @@ -910,13 +917,6 @@ 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; -- 2.39.5