From: Tao Ma <boyu.mt@taobao.com>
Date: Wed, 26 Oct 2011 15:08:39 +0000 (-0400)
Subject: ext4: don't check io->flag when setting EXT4_STATE_DIO_UNWRITTEN inode state
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b3ff05690845911cc40387176f0bc5a7af9ef3ff;p=mv-sheeva.git

ext4: don't check io->flag when setting EXT4_STATE_DIO_UNWRITTEN inode state

When we want to convert the unitialized extent in direct write, we can
either do it in ext4_end_io_nolock(AIO case) or in
ext4_ext_direct_IO(non AIO case) and EXT4_I(inode)->cur_aio_dio is a
guard for ext4_ext_map_blocks to find the right case.  In e9e3bcecf,
we mistakenly change it by:

-			if (io)
+			if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
 				io->flag = EXT4_IO_END_UNWRITTEN;
-			else
+				atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
+			} else
 				ext4_set_inode_state(inode,
 						     EXT4_STATE_DIO_UNWRITTEN);

So now if we map 2 blocks, and the first one set the
EXT_IO_END_UNWRITTEN, the 2nd mapping will set inode state because of
the check for the flag. This is wrong.

Cc: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 797b63b5974..c2ac06cb2d4 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3390,9 +3390,11 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
 		 * that this IO needs to conversion to written when IO is
 		 * completed
 		 */
-		if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
-			io->flag = EXT4_IO_END_UNWRITTEN;
-			atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
+		if (io) {
+			if (!(io->flag & EXT4_IO_END_UNWRITTEN)) {
+				io->flag = EXT4_IO_END_UNWRITTEN;
+				atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
+			}
 		} else
 			ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
 		if (ext4_should_dioread_nolock(inode))
@@ -3946,9 +3948,11 @@ got_allocated_blocks:
 		 * that we need to perform conversion when IO is done.
 		 */
 		if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
-			if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
-				io->flag = EXT4_IO_END_UNWRITTEN;
-				atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
+			if (io) {
+				if (!(io->flag & EXT4_IO_END_UNWRITTEN)) {
+					io->flag = EXT4_IO_END_UNWRITTEN;
+					atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
+				}
 			} else
 				ext4_set_inode_state(inode,
 						     EXT4_STATE_DIO_UNWRITTEN);