[PATCH] ext4: fix unjournalled bg descriptor while initializing inode bitmap
From: Theodore Ts'o <tytso@mit.edu>
Date: 2014-07-05 20:28:51
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
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 <tytso@mit.edu> 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 a87455d..0840bf3 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;
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2.0.0