From a2dc52b5d1d8cc280b3e795abf1c80ac8c49f30c Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Tue, 12 May 2009 13:51:29 -0400
Subject: [PATCH] ext4: Add BUG_ON debugging checks to
noalloc_get_block_write()
Enforce that noalloc_get_block_write() is only called to map one block
at a time, and that it always is successful in finding a mapping for
given an inode's logical block block number if it is called with
create == 1.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
fs/ext4/inode.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index fd5f27a9b81bb..e6113c3a126f8 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2433,11 +2433,14 @@ static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
int ret = 0;
unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
+ BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
+
/*
* we don't want to do block allocation in writepage
* so call get_block_wrap with create = 0
*/
ret = ext4_get_blocks(NULL, inode, iblock, max_blocks, bh_result, 0);
+ BUG_ON(create && ret == 0);
if (ret > 0) {
bh_result->b_size = (ret << inode->i_blkbits);
ret = 0;
--
2.30.2