Anand Jain
2014-Mar-17 11:58 UTC
[PATCH] Btrfs: all super blocks of the replaced disk must be scratched
In a normal scenario when sys-admin replaces a disk, the
expeted is btrfs will release the disk completely.
However the below test case gives a wrong impression that
replaced disk is still is in use.
$ btrfs rep start /dev/sde /dev/sdg4 /btrfs
$ mkfs.btrfs /dev/sde
/dev/sde appears to contain an existing filesystem (btrfs).
Error: Use the -f option to force overwrite.
---
fs/btrfs/volumes.c | 33 +++++++++++++++++++++++++--------
1 file changed, 25 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 3c44800..06717a5 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6286,16 +6286,33 @@ int btrfs_scratch_superblock(struct btrfs_device
*device)
{
struct buffer_head *bh;
struct btrfs_super_block *disk_super;
+ int i;
+ u64 bytenr;
- bh = btrfs_read_dev_super(device->bdev);
- if (!bh)
- return -EINVAL;
- disk_super = (struct btrfs_super_block *)bh->b_data;
+ for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+ bytenr = btrfs_sb_offset(i);
+ if (bytenr + BTRFS_SUPER_INFO_SIZE >+
i_size_read(device->bdev->bd_inode))
+ break;
- memset(&disk_super->magic, 0, sizeof(disk_super->magic));
- set_buffer_dirty(bh);
- sync_dirty_buffer(bh);
- brelse(bh);
+ bh = __bread(device->bdev, bytenr / 4096,
+ BTRFS_SUPER_INFO_SIZE);
+ if (!bh)
+ continue;
+
+ disk_super = (struct btrfs_super_block *)bh->b_data;
+ if (btrfs_super_bytenr(disk_super) != bytenr ||
+ btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
+ brelse(bh);
+ continue;
+ }
+
+ memset(&disk_super->magic, 0, sizeof(disk_super->magic));
+
+ set_buffer_dirty(bh);
+ sync_dirty_buffer(bh);
+ brelse(bh);
+ }
return 0;
}
--
1.8.5.3
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html