New buffers against uptodate pages are simply be marked uptodate, while the
buffer_new bit remains set. This causes error-case code to zero out parts
of those buffers because it thinks they contain stale data: wrong, they
are actually uptodate so this is a data loss situation.
Fix this by actually clearning buffer_new and marking the buffer dirty. It
makes sense to always clear buffer_new before setting a buffer uptodate.
Cc: Linux Memory Management <linux-mm@xxxxxxxxx>
Cc: Linux Filesystems <linux-fsdevel@xxxxxxxxxxxxxxx>
Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
fs/buffer.c | 2 ++
1 file changed, 2 insertions(+)
Index: linux-2.6/fs/buffer.c
===================================================================
--- linux-2.6.orig/fs/buffer.c
+++ linux-2.6/fs/buffer.c
@@ -1816,7 +1816,9 @@ static int __block_prepare_write(struct
unmap_underlying_metadata(bh->b_bdev,
bh->b_blocknr);
if (PageUptodate(page)) {
+ clear_buffer_new(bh);
set_buffer_uptodate(bh);
+ mark_buffer_dirty(bh);
continue;
}
if (block_end > to || block_start < from) {
--
-
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