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authorTheodore Ts'o <tytso@mit.edu>2014-07-05 22:28:35 +0200
committerTheodore Ts'o <tytso@mit.edu>2014-07-05 22:28:35 +0200
commit61c219f5814277ecb71d64cb30297028d6665979 (patch)
treeaec6f25ce767bcaf3564f83ccfd2a08cde524b9b
parentMerge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kerne... (diff)
downloadlinux-61c219f5814277ecb71d64cb30297028d6665979.tar.xz
linux-61c219f5814277ecb71d64cb30297028d6665979.zip
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 <tytso@mit.edu> Cc: stable@vger.kernel.org
-rw-r--r--fs/ext4/ialloc.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index a87455df38bc..0840bf321cdb 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;