Btrfs: notreelog mount option

Add a 'notreelog' mount option to disable the tree log (used by fsync,
O_SYNC writes).  This is much slower, but the tree logging produces
inconsistent views into the FS for ceph.

Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 2ceb40b794a8..3baa2c109e55 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -67,7 +67,8 @@ static void btrfs_put_super(struct super_block *sb)
 enum {
         Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
         Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
-        Opt_ssd, Opt_thread_pool, Opt_noacl,  Opt_compress, Opt_err,
+        Opt_ssd, Opt_thread_pool, Opt_noacl,  Opt_compress, Opt_notreelog,
+        Opt_err,
 };
 
 static match_table_t tokens = {
@@ -84,6 +85,7 @@ static match_table_t tokens = {
         {Opt_compress, "compress"},
         {Opt_ssd, "ssd"},
         {Opt_noacl, "noacl"},
+        {Opt_notreelog, "notreelog"},
         {Opt_err, NULL},
 };
 
@@ -223,6 +225,10 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                 case Opt_noacl:
                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
                         break;
+                case Opt_notreelog:
+                        printk(KERN_INFO "btrfs: disabling tree log\n");
+                        btrfs_set_opt(info->mount_opt, NOTREELOG);
+                        break;
                 default:
                         break;
                 }
@@ -412,6 +418,8 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
                 seq_puts(seq, ",compress");
         if (btrfs_test_opt(root, SSD))
                 seq_puts(seq, ",ssd");
+        if (btrfs_test_opt(root, NOTREELOG))
+                seq_puts(seq, ",notreelog");
         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
                 seq_puts(seq, ",noacl");
         return 0;