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>

1 files changed, 45 insertions, 28 deletions

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 1e12930f8b94..ebeb746c4845 100644
--- 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))