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Subject[patch 2/3] fs: buffer don't PageUptodate without page locked
Date
__block_write_full_page is calling SetPageUptodate without the page locked.
This is unusual, but not incorrect, as PG_writeback is still set.

However with the previous patch, this is now a problem: so don't bother
setting the page uptodate in this case (it is weird that the write path
does such a thing anyway). Instead just leave it to the read side to bring
the page uptodate when it notices that all buffers are uptodate.

Signed-off-by: Nick Piggin <npiggin@suse.de>

Index: linux-2.6/fs/buffer.c
===================================================================
--- linux-2.6.orig/fs/buffer.c
+++ linux-2.6/fs/buffer.c
@@ -1679,6 +1679,7 @@ static int __block_write_full_page(struc
*/
BUG_ON(PageWriteback(page));
set_page_writeback(page);
+ unlock_page(page);

do {
struct buffer_head *next = bh->b_this_page;
@@ -1688,7 +1689,6 @@ static int __block_write_full_page(struc
}
bh = next;
} while (bh != head);
- unlock_page(page);

err = 0;
done:
@@ -1698,17 +1698,8 @@ done:
* clean. Someone wrote them back by hand with
* ll_rw_block/submit_bh. A rare case.
*/
- int uptodate = 1;
- do {
- if (!buffer_uptodate(bh)) {
- uptodate = 0;
- break;
- }
- bh = bh->b_this_page;
- } while (bh != head);
- if (uptodate)
- SetPageUptodate(page);
end_page_writeback(page);
+
/*
* The page and buffer_heads can be released at any time from
* here on.
-
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