Btrfs: add mount option to force UUID tree checking

This should never be needed, but since all functions are there
to check and rebuild the UUID tree, a mount option is added that
allows to force this check and rebuild procedure.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

3 files changed, 10 insertions, 2 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 8c954766db93..0ef9d866952f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1998,6 +1998,7 @@ struct btrfs_ioctl_defrag_range_args {
 #define BTRFS_MOUNT_CHECK_INTEGRITY     (1 << 20)
 #define BTRFS_MOUNT_CHECK_INTEGRITY_INCLUDING_EXTENT_DATA (1 << 21)
 #define BTRFS_MOUNT_PANIC_ON_FATAL_ERROR        (1 << 22)
+#define BTRFS_MOUNT_RESCAN_UUID_TREE    (1 << 23)
 
 #define BTRFS_DEFAULT_COMMIT_INTERVAL   (30)
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e7ef82ad0d26..00914a62abec 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2929,7 +2929,8 @@ retry_root_backup:
                         close_ctree(tree_root);
                         return ret;
                 }
-        } else if (check_uuid_tree) {
+        } else if (check_uuid_tree ||
+                   btrfs_test_opt(tree_root, RESCAN_UUID_TREE)) {
                 pr_info("btrfs: checking UUID tree\n");
                 ret = btrfs_check_uuid_tree(fs_info);
                 if (ret) {
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 1bd0bb523660..57090b4284fe 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -321,7 +321,7 @@ enum {
         Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
         Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
         Opt_check_integrity, Opt_check_integrity_including_extent_data,
-        Opt_check_integrity_print_mask, Opt_fatal_errors,
+        Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
         Opt_commit_interval,
         Opt_err,
 };
@@ -362,6 +362,7 @@ static match_table_t tokens = {
         {Opt_check_integrity, "check_int"},
         {Opt_check_integrity_including_extent_data, "check_int_data"},
         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
+        {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
         {Opt_fatal_errors, "fatal_errors=%s"},
         {Opt_commit_interval, "commit=%d"},
         {Opt_err, NULL},
@@ -572,6 +573,9 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                 case Opt_space_cache:
                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
                         break;
+                case Opt_rescan_uuid_tree:
+                        btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
+                        break;
                 case Opt_no_space_cache:
                         printk(KERN_INFO "btrfs: disabling disk space caching\n");
                         btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
@@ -979,6 +983,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
                 seq_puts(seq, ",space_cache");
         else
                 seq_puts(seq, ",nospace_cache");
+        if (btrfs_test_opt(root, RESCAN_UUID_TREE))
+                seq_puts(seq, ",rescan_uuid_tree");
         if (btrfs_test_opt(root, CLEAR_CACHE))
                 seq_puts(seq, ",clear_cache");
         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))