From 025ffbf352ced17d32e585adbafe84981745043a Mon Sep 17 00:00:00 2001
From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Date: Thu, 5 May 2011 01:23:57 +0900
Subject: [PATCH] --- yaml --- r: 247928 b: refs/heads/master c:
 cfb0a4bfd8736418cbe5cbc115cabc84b527111e h: refs/heads/master v: v3

---
 [refs]                  |  2 +-
 trunk/fs/nilfs2/super.c | 57 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index feeb1beaf5b7..785033d4f367 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 619205da5b567504310daf829dede1187fa29bbc
+refs/heads/master: cfb0a4bfd8736418cbe5cbc115cabc84b527111e
diff --git a/trunk/fs/nilfs2/super.c b/trunk/fs/nilfs2/super.c
index 062cca065195..eba5b53b1080 100644
--- a/trunk/fs/nilfs2/super.c
+++ b/trunk/fs/nilfs2/super.c
@@ -347,6 +347,63 @@ int nilfs_cleanup_super(struct super_block *sb)
 	return ret;
 }
 
+/**
+ * nilfs_move_2nd_super - relocate secondary super block
+ * @sb: super block instance
+ * @sb2off: new offset of the secondary super block (in bytes)
+ */
+static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
+{
+	struct the_nilfs *nilfs = sb->s_fs_info;
+	struct buffer_head *nsbh;
+	struct nilfs_super_block *nsbp;
+	sector_t blocknr, newblocknr;
+	unsigned long offset;
+	int sb2i = -1;  /* array index of the secondary superblock */
+	int ret = 0;
+
+	/* nilfs->ns_sem must be locked by the caller. */
+	if (nilfs->ns_sbh[1] &&
+	    nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
+		sb2i = 1;
+		blocknr = nilfs->ns_sbh[1]->b_blocknr;
+	} else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
+		sb2i = 0;
+		blocknr = nilfs->ns_sbh[0]->b_blocknr;
+	}
+	if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
+		goto out;  /* super block location is unchanged */
+
+	/* Get new super block buffer */
+	newblocknr = sb2off >> nilfs->ns_blocksize_bits;
+	offset = sb2off & (nilfs->ns_blocksize - 1);
+	nsbh = sb_getblk(sb, newblocknr);
+	if (!nsbh) {
+		printk(KERN_WARNING
+		       "NILFS warning: unable to move secondary superblock "
+		       "to block %llu\n", (unsigned long long)newblocknr);
+		ret = -EIO;
+		goto out;
+	}
+	nsbp = (void *)nsbh->b_data + offset;
+	memset(nsbp, 0, nilfs->ns_blocksize);
+
+	if (sb2i >= 0) {
+		memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
+		brelse(nilfs->ns_sbh[sb2i]);
+		nilfs->ns_sbh[sb2i] = nsbh;
+		nilfs->ns_sbp[sb2i] = nsbp;
+	} else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
+		/* secondary super block will be restored to index 1 */
+		nilfs->ns_sbh[1] = nsbh;
+		nilfs->ns_sbp[1] = nsbp;
+	} else {
+		brelse(nsbh);
+	}
+out:
+	return ret;
+}
+
 static void nilfs_put_super(struct super_block *sb)
 {
 	struct the_nilfs *nilfs = sb->s_fs_info;