nilfs2: use checkpoint tree for mount check of snapshots

This rewrites nilfs_checkpoint_is_mounted() function so that it
decides whether a checkpoint is mounted by whether the corresponding
root object is found in checkpoint tree.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 11 insertions, 17 deletions

diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index f1d599273d9e..89c78562d0e9 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -954,26 +954,20 @@ struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *nilfs,
 int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno,
                                 int snapshot_mount)
 {
-        struct nilfs_sb_info *sbi;
-        int ret = 0;
+        struct nilfs_root *root;
+        int ret;
 
-        down_read(&nilfs->ns_super_sem);
-        if (cno == 0 || cno > nilfs->ns_cno)
-                goto out_unlock;
+        if (cno < 0 || cno > nilfs->ns_cno)
+                return false;
 
-        list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
-                if (sbi->s_snapshot_cno == cno &&
-                    (!snapshot_mount || nilfs_test_opt(sbi, SNAPSHOT))) {
-                                        /* exclude read-only mounts */
-                        ret++;
-                        break;
-                }
-        }
-        /* for protecting recent checkpoints */
         if (cno >= nilfs_last_cno(nilfs))
-                ret++;
+                return true;    /* protect recent checkpoints */
 
- out_unlock:
-        up_read(&nilfs->ns_super_sem);
+        ret = false;
+        root = nilfs_lookup_root(nilfs, cno);
+        if (root) {
+                ret = true;
+                nilfs_put_root(root);
+        }
         return ret;
 }