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>
diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c
index b905ae3..034fcfd 100644
--- a/fs/afs/mntpt.c
+++ b/fs/afs/mntpt.c
@@ -68,13 +68,11 @@
}
ret = -EIO;
- wait_on_page_locked(page);
- buf = kmap(page);
- if (!PageUptodate(page))
- goto out_free;
if (PageError(page))
goto out_free;
+ buf = kmap(page);
+
/* examine the symlink's contents */
size = vnode->status.size;
_debug("symlink to %*.*s", (int) size, (int) size, buf);
@@ -91,8 +89,8 @@
ret = 0;
-out_free:
kunmap(page);
+out_free:
page_cache_release(page);
out:
_leave(" = %d", ret);
@@ -171,8 +169,7 @@
}
ret = -EIO;
- wait_on_page_locked(page);
- if (!PageUptodate(page) || PageError(page))
+ if (PageError(page))
goto error;
buf = kmap(page);