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| author | Darrick J. Wong <darrick.wong@oracle.com> | 2014-10-14 10:35:49 +0400 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-11-13 21:02:36 +0300 |
| commit | 9154dd792c9820b25d51e67e6e8e7ae277b64250 (patch) | |
| tree | b7462909abe9316118b56c684d4a4470f557a3b1 /fs/ext4 | |
| parent | c8137a7d271bc709697ecac2dfc88d6a226f2124 (diff) | |
| download | linux-9154dd792c9820b25d51e67e6e8e7ae277b64250.tar.xz | |
ext4: check s_chksum_driver when looking for bg csum presence
commit 813d32f91333e4c33d5a19b67167c4bae42dae75 upstream.
Convert the ext4_has_group_desc_csum predicate to look for a checksum
driver instead of the metadata_csum flag and change the bg checksum
calculation function to look for GDT_CSUM before taking the crc16
path.
Without this patch, if we mount with ^uninit_bg,^metadata_csum and
later metadata_csum gets turned on by accident, the block group
checksum functions will incorrectly assume that checksumming is
enabled (metadata_csum) but that crc16 should be used
(!s_chksum_driver). This is totally wrong, so fix the predicate
and the checksum formula selection.
(Granted, if the metadata_csum feature bit gets enabled on a live FS
then something underhanded is going on, but we could at least avoid
writing garbage into the on-disk fields.)
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/ext4.h | 4 | ||||
| -rw-r--r-- | fs/ext4/super.c | 4 |
2 files changed, 6 insertions, 2 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index bd5f351ef10b..29c4e30bf4ca 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2324,8 +2324,8 @@ extern int ext4_register_li_request(struct super_block *sb, static inline int ext4_has_group_desc_csum(struct super_block *sb) { return EXT4_HAS_RO_COMPAT_FEATURE(sb, - EXT4_FEATURE_RO_COMPAT_GDT_CSUM | - EXT4_FEATURE_RO_COMPAT_METADATA_CSUM); + EXT4_FEATURE_RO_COMPAT_GDT_CSUM) || + (EXT4_SB(sb)->s_chksum_driver != NULL); } static inline int ext4_has_metadata_csum(struct super_block *sb) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 4ddd6cf12f63..64a94388bc8d 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2000,6 +2000,10 @@ static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group, } /* old crc16 code */ + if (!(sbi->s_es->s_feature_ro_compat & + cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM))) + return 0; + offset = offsetof(struct ext4_group_desc, bg_checksum); crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid)); |