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>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e572cf4..f4dfbb7 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1850,6 +1850,14 @@
if (IS_ERR(fs_info->transaction_kthread))
goto fail_cleaner;
+ if (!btrfs_test_opt(tree_root, SSD) &&
+ !btrfs_test_opt(tree_root, NOSSD) &&
+ !fs_info->fs_devices->rotating) {
+ printk(KERN_INFO "Btrfs detected SSD devices, enabling SSD "
+ "mode\n");
+ btrfs_set_opt(fs_info->mount_opt, SSD);
+ }
+
if (btrfs_super_log_root(disk_super) != 0) {
u64 bytenr = btrfs_super_log_root(disk_super);
@@ -1893,6 +1901,7 @@
fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
if (!fs_info->fs_root)
goto fail_trans_kthread;
+
return tree_root;
fail_trans_kthread: