1 files changed, 26 insertions, 9 deletions

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 77f1e5778d1c..0ef8c71bde8e 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -372,10 +372,31 @@ static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 		goto out;
 	}
 	nsbp = (void *)nsbh->b_data + offset;
-	memset(nsbp, 0, nilfs->ns_blocksize);
 
+	lock_buffer(nsbh);
 	if (sb2i >= 0) {
+		/*
+		 * The position of the second superblock only changes by 4KiB,
+		 * which is larger than the maximum superblock data size
+		 * (= 1KiB), so there is no need to use memmove() to allow
+		 * overlap between source and destination.
+		 */
 		memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
+
+		/*
+		 * Zero fill after copy to avoid overwriting in case of move
+		 * within the same block.
+		 */
+		memset(nsbh->b_data, 0, offset);
+		memset((void *)nsbp + nilfs->ns_sbsize, 0,
+		       nsbh->b_size - offset - nilfs->ns_sbsize);
+	} else {
+		memset(nsbh->b_data, 0, nsbh->b_size);
+	}
+	set_buffer_uptodate(nsbh);
+	unlock_buffer(nsbh);
+
+	if (sb2i >= 0) {
 		brelse(nilfs->ns_sbh[sb2i]);
 		nilfs->ns_sbh[sb2i] = nsbh;
 		nilfs->ns_sbp[sb2i] = nsbp;
@@ -1278,14 +1299,11 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 {
 	struct nilfs_super_data sd;
 	struct super_block *s;
-	fmode_t mode = FMODE_READ | FMODE_EXCL;
 	struct dentry *root_dentry;
 	int err, s_new = false;
 
-	if (!(flags & SB_RDONLY))
-		mode |= FMODE_WRITE;
-
-	sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
+	sd.bdev = blkdev_get_by_path(dev_name, sb_open_mode(flags), fs_type,
+				     NULL);
 	if (IS_ERR(sd.bdev))
 		return ERR_CAST(sd.bdev);
 
@@ -1319,7 +1337,6 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 		s_new = true;
 
 		/* New superblock instance created */
-		s->s_mode = mode;
 		snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
 		sb_set_blocksize(s, block_size(sd.bdev));
 
@@ -1357,7 +1374,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 	}
 
 	if (!s_new)
-		blkdev_put(sd.bdev, mode);
+		blkdev_put(sd.bdev, fs_type);
 
 	return root_dentry;
 
@@ -1366,7 +1383,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 
  failed:
 	if (!s_new)
-		blkdev_put(sd.bdev, mode);
+		blkdev_put(sd.bdev, fs_type);
 	return ERR_PTR(err);
 }