Jeff Mahoney <jeffm@xxxxxxxx> wrote:
>
> In my experience, the loop is actually outside of
> __find_get_block_slow(), in __getblk_slow(). I've been using xmon to
> interrupt the kernel, and the results vary but are all rooted in the
> for(;;) loop in __getblk_slow. It appears as though grow_buffers is
> finding/creating the page, but then __find_get_block can't locate the
> buffer it needs.
Yes, that'll happen. Because there are still buffers attached to the page
which have the wrong blocksize. Say, if someone is trying to read a 2k
buffer_head which is backed by a page which already has 1k buffer_heads
attached to it.
Does your kernel not have that big printk in __find_get_block_slow()? If
it does, maybe some of the buffers are unmapped. Try:
--- 25/fs/buffer.c~a Tue Feb 22 15:27:35 2005
+++ 25-akpm/fs/buffer.c Tue Feb 22 15:27:41 2005
@@ -456,7 +456,7 @@ __find_get_block_slow(struct block_devic
* file io on the block device and getblk. It gets dealt with
* elsewhere, don't buffer_error if we had some unmapped buffers
*/
- if (all_mapped) {
+ {
printk("__find_get_block_slow() failed. "
"block=%llu, b_blocknr=%llu\n",
(unsigned long long)block, (unsigned long long)bh->b_blocknr);
_
