ocfs2: add necessary check in case sb_getblk() fails

sb_getblk() may return an err, so add a check for bh.

[joseph.qi@huawei.com: also add a check after calling sb_getblk() in ocfs2_create_xattr_block()]
Signed-off-by: Rui Xiang <rui.xiang@huawei.com>
Reviewed-by: Jie Liu <jeff.liu@oracle.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/refcounttree.c

@@ -612,6 +612,11 @@ static int ocfs2_create_refcount_tree(struct inode *inode,
 	}
 
 	new_bh = sb_getblk(inode->i_sb, first_blkno);
+	if (!new_bh) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out_commit;
+	}
 	ocfs2_set_new_buffer_uptodate(&new_tree->rf_ci, new_bh);
 
 	ret = ocfs2_journal_access_rb(handle, &new_tree->rf_ci, new_bh,

fs/ocfs2/xattr.c

@@ -2864,6 +2864,12 @@ static int ocfs2_create_xattr_block(struct inode *inode,
 	}
 
 	new_bh = sb_getblk(inode->i_sb, first_blkno);
+	if (!new_bh) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto end;
+	}
+
 	ocfs2_set_new_buffer_uptodate(INODE_CACHE(inode), new_bh);
 
 	ret = ocfs2_journal_access_xb(ctxt->handle, INODE_CACHE(inode),