nilfs2: split out nilfs_attach_snapshot

This splits the code to attach snapshots into a separate routine for
convenience sake.

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

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 1e12930..ebeb746 100644 (file)
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -783,6 +783,40 @@ static int nilfs_get_root_dentry(struct super_block *sb,
        return ret;
 }
 
+static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
+                                struct dentry **root_dentry)
+{
+       struct the_nilfs *nilfs = NILFS_SB(s)->s_nilfs;
+       struct nilfs_root *root;
+       int ret;
+
+       down_read(&nilfs->ns_segctor_sem);
+       ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
+       up_read(&nilfs->ns_segctor_sem);
+       if (ret < 0) {
+               ret = (ret == -ENOENT) ? -EINVAL : ret;
+               goto out;
+       } else if (!ret) {
+               printk(KERN_ERR "NILFS: The specified checkpoint is "
+                      "not a snapshot (checkpoint number=%llu).\n",
+                      (unsigned long long)cno);
+               ret = -EINVAL;
+               goto out;
+       }
+
+       ret = nilfs_attach_checkpoint(NILFS_SB(s), cno, false, &root);
+       if (ret) {
+               printk(KERN_ERR "NILFS: error loading snapshot "
+                      "(checkpoint number=%llu).\n",
+              (unsigned long long)cno);
+               goto out;
+       }
+       ret = nilfs_get_root_dentry(s, root, root_dentry);
+       nilfs_put_root(root);
+ out:
+       return ret;
+}
+
 /**
  * nilfs_fill_super() - initialize a super block instance
  * @sb: super_block
@@ -800,7 +834,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
        struct nilfs_sb_info *sbi;
        struct nilfs_root *fsroot;
        __u64 cno;
-       int err, curr_mnt;
+       int err;
 
        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
        if (!sbi)
@@ -841,35 +875,17 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
        if (err)
                goto failed_sbi;
 
-       cno = nilfs_last_cno(nilfs);
-       curr_mnt = true;
-
-       if (sb->s_flags & MS_RDONLY) {
-               if (nilfs_test_opt(sbi, SNAPSHOT)) {
-                       down_read(&nilfs->ns_segctor_sem);
-                       err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
-                                                      sbi->s_snapshot_cno);
-                       up_read(&nilfs->ns_segctor_sem);
-                       if (err < 0) {
-                               if (err == -ENOENT)
-                                       err = -EINVAL;
-                               goto failed_sbi;
-                       }
-                       if (!err) {
-                               printk(KERN_ERR
-                                      "NILFS: The specified checkpoint is "
-                                      "not a snapshot "
-                                      "(checkpoint number=%llu).\n",
-                                      (unsigned long long)sbi->s_snapshot_cno);
-                               err = -EINVAL;
-                               goto failed_sbi;
-                       }
-                       cno = sbi->s_snapshot_cno;
-                       curr_mnt = false;
-               }
+       if (nilfs_test_opt(sbi, SNAPSHOT)) {
+               err = nilfs_attach_snapshot(sb, sbi->s_snapshot_cno,
+                                           &sb->s_root);
+               if (err)
+                       goto failed_sbi;
+
+               goto add_to_supers;
        }
 
-       err = nilfs_attach_checkpoint(sbi, cno, curr_mnt, &fsroot);
+       cno = nilfs_last_cno(nilfs);
+       err = nilfs_attach_checkpoint(sbi, cno, true, &fsroot);
        if (err) {
                printk(KERN_ERR "NILFS: error loading a checkpoint"
                       " (checkpoint number=%llu).\n", (unsigned long long)cno);
@@ -894,6 +910,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
                up_write(&nilfs->ns_sem);
        }
 
+ add_to_supers:
        down_write(&nilfs->ns_super_sem);
        list_add(&sbi->s_list, &nilfs->ns_supers);
        if (!nilfs_test_opt(sbi, SNAPSHOT))