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, 2 insertions, 16 deletions

diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 7659cc192995..1c08fefe487a 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -2532,14 +2532,7 @@ int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
                 page = read_mapping_page(mapping, idx, NULL);
                 if (IS_ERR(page)) {
                         ntfs_error(vol->sb, "Failed to read first partial "
-                                        "page (sync error, index 0x%lx).", idx);
-                        return PTR_ERR(page);
-                }
-                wait_on_page_locked(page);
-                if (unlikely(!PageUptodate(page))) {
-                        ntfs_error(vol->sb, "Failed to read first partial page "
-                                        "(async error, index 0x%lx).", idx);
-                        page_cache_release(page);
+                                        "page (error, index 0x%lx).", idx);
                         return PTR_ERR(page);
                 }
                 /*
@@ -2602,14 +2595,7 @@ int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
                 page = read_mapping_page(mapping, idx, NULL);
                 if (IS_ERR(page)) {
                         ntfs_error(vol->sb, "Failed to read last partial page "
-                                        "(sync error, index 0x%lx).", idx);
-                        return PTR_ERR(page);
-                }
-                wait_on_page_locked(page);
-                if (unlikely(!PageUptodate(page))) {
-                        ntfs_error(vol->sb, "Failed to read last partial page "
-                                        "(async error, index 0x%lx).", idx);
-                        page_cache_release(page);
+                                        "(error, index 0x%lx).", idx);
                         return PTR_ERR(page);
                 }
                 kaddr = kmap_atomic(page, KM_USER0);