md: override md superblock recovery_offset for journal device

Journal device stores data in a log structure. We need record the log
start. Here we override md superblock recovery_offset for this purpose.
This field of a journal device is meaningless otherwise.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
This commit is contained in:
Shaohua Li 2015-08-13 14:31:56 -07:00 committed by NeilBrown
parent bac624f3f8
commit 3069aa8def
3 changed files with 17 additions and 2 deletions

View file

@ -258,7 +258,10 @@ struct mdp_superblock_1 {
__le64 data_offset; /* sector start of data, often 0 */
__le64 data_size; /* sectors in this device that can be used for data */
__le64 super_offset; /* sector start of this superblock */
__le64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */
union {
__le64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */
__le64 journal_tail;/* journal tail of journal device (from data_offset) */
};
__le32 dev_number; /* permanent identifier of this device - not role in raid */
__le32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */
__u8 device_uuid[16]; /* user-space setable, ignored by kernel */