Btrfs: check total number of devices when removing missing

If you have a disk failure in RAID1 and then add a new disk to the
array, and then try to remove the missing volume, it will fail.  The
reason is the sanity check only looks at the total number of rw devices,
which is just 2 because we have 2 good disks and 1 bad one.  Instead
check the total number of devices in the array to make sure we can
actually remove the device.  Tested this with a failed disk setup and
with this test we can now run

btrfs-vol -r missing /mount/point

and it works fine.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 5eb7459e3782f8871d4b6c6e4286aa4671f410c6..41ecbb2347f2d3171f7645782ab4e5a39621c84d 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1135,7 +1135,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                root->fs_info->avail_metadata_alloc_bits;
 
        if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
-           root->fs_info->fs_devices->rw_devices <= 4) {
+           root->fs_info->fs_devices->num_devices <= 4) {
                printk(KERN_ERR "btrfs: unable to go below four devices "
                       "on raid10\n");
                ret = -EINVAL;
@@ -1143,7 +1143,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
        }
 
        if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
-           root->fs_info->fs_devices->rw_devices <= 2) {
+           root->fs_info->fs_devices->num_devices <= 2) {
                printk(KERN_ERR "btrfs: unable to go below two "
                       "devices on raid1\n");
                ret = -EINVAL;