diff options
| -rw-r--r-- | fs/btrfs/volumes.c | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 7c538f65214b..5700ab03e84b 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -532,8 +532,19 @@ static noinline int device_list_add(const char *path, * As of now don't allow update to btrfs_fs_device through * the btrfs dev scan cli, after FS has been mounted. */ - if (fs_devices->opened) + if (fs_devices->opened) { return -EBUSY; + } else { + /* + * That is if the FS is _not_ mounted and if you + * are here, that means there is more than one + * disk with same uuid and devid.We keep the one + * with larger generation number or the last-in if + * generation are equal. + */ + if (found_transid < device->generation) + return -EEXIST; + } name = rcu_string_strdup(path, GFP_NOFS); if (!name) @@ -546,6 +557,15 @@ static noinline int device_list_add(const char *path, } } + /* + * Unmount does not free the btrfs_device struct but would zero + * generation along with most of the other members. So just update + * it back. We need it to pick the disk with largest generation + * (as above). + */ + if (!fs_devices->opened) + device->generation = found_transid; + if (found_transid > fs_devices->latest_trans) { fs_devices->latest_devid = devid; fs_devices->latest_trans = found_transid; |