From: Badari Pulavarty <pbadari@us.ibm.com>
Here is the fix for dio_new_bio() BUG() with fsx tests. The problem is, I
changed dio_pages_in_io calculation to be exactly the number of pages we
needed to map the user-buffer to do the IO. But with fine-grain alignment
(non fs-blocksize), we may need 2 more pages (ZERO_PAGE) to zero out first
and last block if needed.
Here is the bug info.
http://bugme.osdl.org/show_bug.cgi?id=3447
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/fs/direct-io.c | 10 +++++++++-
1 files changed, 9 insertions(+), 1 deletion(-)
diff -puN fs/direct-io.c~dio-fine-alignment-and-pages-in-io fs/direct-io.c
--- 25/fs/direct-io.c~dio-fine-alignment-and-pages-in-io 2004-09-23 18:12:22.020145480 -0700
+++ 25-akpm/fs/direct-io.c 2004-09-23 18:12:22.024144872 -0700
@@ -958,7 +958,15 @@ direct_io_worker(int rw, struct kiocb *i
dio->bio_list = NULL;
dio->waiter = NULL;
- dio->pages_in_io = 0;
+ /*
+ * In case of non-aligned buffers, we may need 2 more
+ * pages since we need to zero out first and last block.
+ */
+ if (unlikely(dio->blkfactor))
+ dio->pages_in_io = 2;
+ else
+ dio->pages_in_io = 0;
+
for (seg = 0; seg < nr_segs; seg++) {
user_addr = (unsigned long)iov[seg].iov_base;
dio->pages_in_io +=
_