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/namei.c b/fs/namei.c
index 880052c..94b2f60 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2671,19 +2671,9 @@
struct address_space *mapping = dentry->d_inode->i_mapping;
page = read_mapping_page(mapping, 0, NULL);
if (IS_ERR(page))
- goto sync_fail;
- wait_on_page_locked(page);
- if (!PageUptodate(page))
- goto async_fail;
+ return (char*)page;
*ppage = page;
return kmap(page);
-
-async_fail:
- page_cache_release(page);
- return ERR_PTR(-EIO);
-
-sync_fail:
- return (char*)page;
}
int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)