Btrfs: autodetect SSD devices

During mount, btrfs will check the queue nonrot flag
for all the devices found in the FS.  If they are all
non-rotating, SSD mode is enabled by default.

If the FS was mounted with -o nossd, the non-rotating
flag is ignored.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 27d5f37b845f..3f4a5932eac9 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -605,6 +605,9 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
                 device->in_fs_metadata = 0;
                 device->mode = flags;
 
+                if (!blk_queue_nonrot(bdev_get_queue(bdev)))
+                        fs_devices->rotating = 1;
+
                 fs_devices->open_devices++;
                 if (device->writeable) {
                         fs_devices->rw_devices++;
@@ -1473,6 +1476,9 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         root->fs_info->fs_devices->rw_devices++;
         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
 
+        if (!blk_queue_nonrot(bdev_get_queue(bdev)))
+                root->fs_info->fs_devices->rotating = 1;
+
         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
         btrfs_set_super_total_bytes(&root->fs_info->super_copy,
                                     total_bytes + device->total_bytes);