ocfs2: lock the metaecc process for xattr bucket

For other metadata in ocfs2, metaecc is checked in ocfs2_read_blocks
with io_mutex held. While for xattr bucket, it is calculated by
the whole buckets. So we have to add a spin_lock to prevent multiple
processes calculating metaecc.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Tested-by: Tristan Ye <tristan.ye@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

fs/ocfs2/ocfs2.h

@@ -341,6 +341,9 @@ struct ocfs2_super
 	struct ocfs2_node_map		osb_recovering_orphan_dirs;
 	unsigned int			*osb_orphan_wipes;
 	wait_queue_head_t		osb_wipe_event;
+
+	/* used to protect metaecc calculation check of xattr. */
+	spinlock_t osb_xattr_lock;
 };
 
 #define OCFS2_SB(sb)	    ((struct ocfs2_super *)(sb)->s_fs_info)

fs/ocfs2/super.c

@@ -1747,6 +1747,7 @@ static int ocfs2_initialize_super(struct super_block *sb,
 	INIT_LIST_HEAD(&osb->blocked_lock_list);
 	osb->blocked_lock_count = 0;
 	spin_lock_init(&osb->osb_lock);
+	spin_lock_init(&osb->osb_xattr_lock);
 	ocfs2_init_inode_steal_slot(osb);
 
 	atomic_set(&osb->alloc_stats.moves, 0);

fs/ocfs2/xattr.c

@@ -274,10 +274,12 @@ static int ocfs2_read_xattr_bucket(struct ocfs2_xattr_bucket *bucket,
 			       bucket->bu_blocks, bucket->bu_bhs, 0,
 			       NULL);
 	if (!rc) {
+		spin_lock(&OCFS2_SB(bucket->bu_inode->i_sb)->osb_xattr_lock);
 		rc = ocfs2_validate_meta_ecc_bhs(bucket->bu_inode->i_sb,
 						 bucket->bu_bhs,
 						 bucket->bu_blocks,
 						 &bucket_xh(bucket)->xh_check);
+		spin_unlock(&OCFS2_SB(bucket->bu_inode->i_sb)->osb_xattr_lock);
 		if (rc)
 			mlog_errno(rc);
 	}
@@ -310,9 +312,11 @@ static void ocfs2_xattr_bucket_journal_dirty(handle_t *handle,
 {
 	int i;
 
+	spin_lock(&OCFS2_SB(bucket->bu_inode->i_sb)->osb_xattr_lock);
 	ocfs2_compute_meta_ecc_bhs(bucket->bu_inode->i_sb,
 				   bucket->bu_bhs, bucket->bu_blocks,
 				   &bucket_xh(bucket)->xh_check);
+	spin_unlock(&OCFS2_SB(bucket->bu_inode->i_sb)->osb_xattr_lock);
 
 	for (i = 0; i < bucket->bu_blocks; i++)
 		ocfs2_journal_dirty(handle, bucket->bu_bhs[i]);