ext4: Drop EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE flag

commit 1296cc85 upstream (as of v2.6.33-rc6)

We should update reserve space if it is delalloc buffer
and that is indicated by EXT4_GET_BLOCKS_DELALLOC_RESERVE flag.
So use EXT4_GET_BLOCKS_DELALLOC_RESERVE in place of
EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE

[ Stable note: This fixes a corruption cuased by the following
  reproduction case:

  rm -f $TEST_FN
  touch $TEST_FN
  fallocate -n -o 656712 -l 858907 $TEST_FN
  dd if=/dev/zero of=$TEST_FN conv=notrunc bs=1 seek=1011020 count=36983
  sync
  dd if=/dev/zero of=$TEST_FN conv=notrunc bs=1 seek=332121 count=24005
  dd if=/dev/zero of=$TEST_FN conv=notrunc bs=1 seek=1040179 count=93319

  If the filesystem is then unmounted and e2fsck run forced, the
  i_blocks field for the file $TEST_FN will be found to be incorrect. ]
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

fs/ext4/ext4.h

@@ -361,14 +361,11 @@ struct ext4_new_group_data {
 	   so set the magic i_delalloc_reserve_flag after taking the 
 	   inode allocation semaphore for */
 #define EXT4_GET_BLOCKS_DELALLOC_RESERVE	0x0004
-	/* Call ext4_da_update_reserve_space() after successfully 
-	   allocating the blocks */
-#define EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE	0x0008
 	/* caller is from the direct IO path, request to creation of an
 	unitialized extents if not allocated, split the uninitialized
 	extent if blocks has been preallocated already*/
-#define EXT4_GET_BLOCKS_DIO			0x0010
-#define EXT4_GET_BLOCKS_CONVERT			0x0020
+#define EXT4_GET_BLOCKS_DIO			0x0008
+#define EXT4_GET_BLOCKS_CONVERT			0x0010
 #define EXT4_GET_BLOCKS_DIO_CREATE_EXT		(EXT4_GET_BLOCKS_DIO|\
 					 EXT4_GET_BLOCKS_CREATE_UNINIT_EXT)
 	/* Convert extent to initialized after direct IO complete */

fs/ext4/extents.c

@@ -3148,7 +3148,7 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
 	 * But fallocate would have already updated quota and block
 	 * count for this offset. So cancel these reservation
 	 */
-	if (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE)
+	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
 		ext4_da_update_reserve_space(inode, allocated, 0);
 
 map_out:
@@ -3394,7 +3394,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
 	 * Update reserved blocks/metadata blocks after successful
 	 * block allocation which had been deferred till now.
 	 */
-	if (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE)
+	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
 		ext4_da_update_reserve_space(inode, allocated, 1);
 
 	/*

fs/ext4/inode.c

@@ -1358,7 +1358,7 @@ int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
 		 * reserve space here.
 		 */
 		if ((retval > 0) &&
-			(flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE))
+			(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
 			ext4_da_update_reserve_space(inode, retval, 1);
 	}
 	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
@@ -2261,10 +2261,10 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
 	 * variables are updated after the blocks have been allocated.
 	 */
 	new.b_state = 0;
-	get_blocks_flags = (EXT4_GET_BLOCKS_CREATE |
-			    EXT4_GET_BLOCKS_DELALLOC_RESERVE);
+	get_blocks_flags = EXT4_GET_BLOCKS_CREATE;
 	if (mpd->b_state & (1 << BH_Delay))
-		get_blocks_flags |= EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE;
+		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
+
 	blks = ext4_get_blocks(handle, mpd->inode, next, max_blocks,
 			       &new, get_blocks_flags);
 	if (blks < 0) {