[PATCH] ext3: Fix unmapped buffers in transaction's lists
Fix the problem (BUG 4964) with unmapped buffers in transaction's
t_sync_data list. The problem is we need to call filesystem's own
invalidatepage() from block_write_full_page().
block_write_full_page() must call filesystem's invalidatepage(). Otherwise
following nasty race can happen:
proc 1 proc 2
------ ------
- write some new data to 'offset'
=> bh gets to the transactions data list
- starts truncate
=> i_size set to new size
- mpage_writepages()
- ext3_ordered_writepage() to 'offset'
- block_write_full_page()
- page->index > end_index+1
- block_invalidatepage()
- discard_buffer()
- clear_buffer_mapped()
- commit triggers and finds unmapped buffer - BOOM!
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/truncate.c b/mm/truncate.c
index 60c8764..29c18f6 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -13,18 +13,9 @@
#include <linux/pagemap.h>
#include <linux/pagevec.h>
#include <linux/buffer_head.h> /* grr. try_to_release_page,
- block_invalidatepage */
+ do_invalidatepage */
-static int do_invalidatepage(struct page *page, unsigned long offset)
-{
- int (*invalidatepage)(struct page *, unsigned long);
- invalidatepage = page->mapping->a_ops->invalidatepage;
- if (invalidatepage == NULL)
- invalidatepage = block_invalidatepage;
- return (*invalidatepage)(page, offset);
-}
-
static inline void truncate_partial_page(struct page *page, unsigned partial)
{
memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial);