The last week, one of our customer got the corrupted messages in the ldiskfs, then OSS remounted that OST with readonly.
Here is when we got the error messages. the situation is very similar to LU-501, but don't know this is exactly same problem. Please check on this log files.
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.472484] LDISKFS-fs error (device dm-5): ldiskfs_mb_check_ondisk_bitmap: on-disk bitmap for group 23828corrupted: 4190 blocks free in bitmap, 4189 - in gd
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.472677]
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.472727] Aborting journal on device dm-5-8.
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.473961] LDISKFS-fs (dm-5): Remounting filesystem read-only
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.510914] LDISKFS-fs error (device dm-5): ldiskfs_mb_check_ondisk_bitmap: on-disk bitmap for group 23828corrupted: 4190 blocks free in bitmap, 4189 - in gd
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.511103]
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.513219] LDISKFS-fs error (device dm-5): ldiskfs_mb_check_ondisk_bitmap: on-disk bitmap for group 23828corrupted: 4190 blocks free in bitmap, 4189 - in gd
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.513396]
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.515388] LDISKFS-fs error (device dm-5): ldiskfs_mb_check_ondisk_bitmap: on-disk bitmap for group 23828corrupted: 4190 blocks free in bitmap, 4189 - in gd
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.515562]
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.517502] LDISKFS-fs error (device dm-5): ldiskfs_mb_check_ondisk_bitmap: on-disk bitmap for group 23828corrupted: 4190 blocks free in bitmap, 4189 - in gd
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.518511]
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.520586] LDISKFS-fs error (device dm-5): ldiskfs_mb_check_ondisk_bitmap: on-disk bitmap for group 23828corrupted: 4190 blocks free in bitmap, 4189 - in gd
Jan 19 18:25:46 lustre-oss-0-0 kernel: [8145936.520753]