[SRU][Bionic][PATCH 1/1] UBUNTU: SAUCE: ext4: fix ext4_validate_inode_bitmap: comm stress-ng: Corrupt inode bitmap

[Kamal Mostafa]

From: "Theodore Y. Ts'o" <tytso at mit.edu>

BugLink: http://bugs.launchpad.net/bugs/1780137

Fix regression triggered by the stress-ng[*] "chdir" test, with LKML test
patch.

Regression observed on some arm64 server platforms:

    EXT4-fs error (device sda1): ext4_validate_inode_bitmap:99: comm stress-ng: Corrupt inode bitmap

Reference: https://lkml.org/lkml/2018/7/7/2

Reported-by: dann frazier <dann.frazier at canonical.com>
Tested-by: dann frazier <dann.frazier at canonical.com>
Fixes: 044e6e3d74a3 ext4: don't update checksum of new initialized bitmaps
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/ext4/ialloc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 5559313..b5e2cc2 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -91,6 +91,8 @@ static int ext4_validate_inode_bitmap(struct super_block *sb,
 		return -EFSCORRUPTED;
 
 	ext4_lock_group(sb, block_group);
+	if (buffer_verified(bh))
+		goto verified;
 	blk = ext4_inode_bitmap(sb, desc);
 	if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
 					   EXT4_INODES_PER_GROUP(sb) / 8)) {
@@ -108,6 +110,7 @@ static int ext4_validate_inode_bitmap(struct super_block *sb,
 		return -EFSBADCRC;
 	}
 	set_buffer_verified(bh);
+verified:
 	ext4_unlock_group(sb, block_group);
 	return 0;
 }
-- 
2.7.4