Btrfs: Add readahead to the online shrinker, and a mount -o alloc_start= for testing

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

1 files changed, 15 insertions, 1 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 3bbd7f665694..f1b56eb77b1d 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -63,7 +63,8 @@ static void btrfs_put_super (struct super_block * sb)
 }
 
 enum {
-        Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_max_extent, Opt_err,
+        Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_max_extent,
+        Opt_alloc_start, Opt_err,
 };
 
 static match_table_t tokens = {
@@ -71,6 +72,7 @@ static match_table_t tokens = {
         {Opt_nodatasum, "nodatasum"},
         {Opt_nodatacow, "nodatacow"},
         {Opt_max_extent, "max_extent=%s"},
+        {Opt_alloc_start, "alloc_start=%s"},
         {Opt_err, NULL}
 };
 
@@ -162,6 +164,18 @@ static int parse_options (char * options,
                                 }
                         }
                         break;
+                case Opt_alloc_start:
+                        if (info) {
+                                char *num = match_strdup(&args[0]);
+                                if (num) {
+                                        info->alloc_start =
+                                                btrfs_parse_size(num);
+                                        kfree(num);
+                                        printk("btrfs: allocations start at "
+                                               "%Lu\n", info->alloc_start);
+                                }
+                        }
+                        break;
                 default:
                         break;
                 }