Btrfs: Add mount -o degraded to allow mounts to continue with missing devices

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

1 files changed, 15 insertions, 10 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 020e5a83e31f..273a5b511f50 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -65,11 +65,13 @@ static void btrfs_put_super (struct super_block * sb)
 }
 
 enum {
-        Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_max_extent,
-        Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd, Opt_err,
+        Opt_degraded, Opt_subvol, Opt_nodatasum, Opt_nodatacow,
+        Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
+        Opt_ssd, Opt_err,
 };
 
 static match_table_t tokens = {
+        {Opt_degraded, "degraded"},
         {Opt_subvol, "subvol=%s"},
         {Opt_nodatasum, "nodatasum"},
         {Opt_nodatacow, "nodatacow"},
@@ -106,9 +108,8 @@ u64 btrfs_parse_size(char *str)
         return res;
 }
 
-static int parse_options (char * options,
-                          struct btrfs_root *root,
-                          char **subvol_name)
+int btrfs_parse_options(char *options, struct btrfs_root *root,
+                        char **subvol_name)
 {
         char * p;
         struct btrfs_fs_info *info = NULL;
@@ -135,6 +136,12 @@ static int parse_options (char * options,
 
                 token = match_token(p, tokens, args);
                 switch (token) {
+                case Opt_degraded:
+                        if (info) {
+                                printk("btrfs: allowing degraded mounts\n");
+                                btrfs_set_opt(info->mount_opt, DEGRADED);
+                        }
+                        break;
                 case Opt_subvol:
                         if (subvol_name) {
                                 *subvol_name = match_strdup(&args[0]);
@@ -234,7 +241,7 @@ static int btrfs_fill_super(struct super_block * sb,
         sb->s_xattr = btrfs_xattr_handlers;
         sb->s_time_gran = 1;
 
-        tree_root = open_ctree(sb, fs_devices);
+        tree_root = open_ctree(sb, fs_devices, (char *)data);
 
         if (IS_ERR(tree_root)) {
                 printk("btrfs: open_ctree failed\n");
@@ -267,8 +274,6 @@ static int btrfs_fill_super(struct super_block * sb,
                 goto fail_close;
         }
 
-        parse_options((char *)data, tree_root, NULL);
-
         /* this does the super kobj at the same time */
         err = btrfs_sysfs_add_super(tree_root->fs_info);
         if (err)
@@ -341,7 +346,7 @@ int btrfs_get_sb_bdev(struct file_system_type *fs_type,
         if (error)
                 return error;
 
-        bdev = fs_devices->lowest_bdev;
+        bdev = fs_devices->latest_bdev;
         btrfs_lock_volumes();
         s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
         btrfs_unlock_volumes();
@@ -411,7 +416,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
         int ret;
         char *subvol_name = NULL;
 
-        parse_options((char *)data, NULL, &subvol_name);
+        btrfs_parse_options((char *)data, NULL, &subvol_name);
         ret = btrfs_get_sb_bdev(fs_type, flags, dev_name, data, mnt,
                         subvol_name ? subvol_name : "default");
         if (subvol_name)