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/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index b731b09..0770c4b 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -46,7 +46,6 @@
*/
static struct page *ecryptfs_get1page(struct file *file, int index)
{
- struct page *page;
struct dentry *dentry;
struct inode *inode;
struct address_space *mapping;
@@ -54,14 +53,7 @@
dentry = file->f_path.dentry;
inode = dentry->d_inode;
mapping = inode->i_mapping;
- page = read_cache_page(mapping, index,
- (filler_t *)mapping->a_ops->readpage,
- (void *)file);
- if (IS_ERR(page))
- goto out;
- wait_on_page_locked(page);
-out:
- return page;
+ return read_mapping_page(mapping, index, (void *)file);
}
static
@@ -233,7 +225,6 @@
ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
goto out;
}
- wait_on_page_locked(lower_page);
page_data = kmap_atomic(page, KM_USER0);
lower_page_data = kmap_atomic(lower_page, KM_USER1);
memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);