mm: make read_cache_page synchronous

Ensure pages are uptodate after returning from read_cache_page, which allows
us to cut out most of the filesystem-internal PageUptodate calls.

I didn't have a great look down the call chains, but this appears to fixes 7
possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in
ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in
block2mtd.  All depending on whether the filler is async and/or can return
with a !uptodate page.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 4 deletions

diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 2cac56210e2b..bf6e58214538 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -410,11 +410,7 @@ static struct page *reiserfs_get_page(struct inode *dir, unsigned long n)
         mapping_set_gfp_mask(mapping, GFP_NOFS);
         page = read_mapping_page(mapping, n, NULL);
         if (!IS_ERR(page)) {
-                wait_on_page_locked(page);
                 kmap(page);
-                if (!PageUptodate(page))
-                        goto fail;
-
                 if (PageError(page))
                         goto fail;
         }