ext4: get rid of EXT4_MAP_UNINIT flag

Currently EXT4_MAP_UNINIT is used in dioread_nolock case to mark the
cases where we're using dioread_nolock and we're writing into either
unallocated, or unwritten extent, because we need to make sure that
any DIO write into that inode will wait for the extent conversion.

However EXT4_MAP_UNINIT is not only entirely misleading name but also
unnecessary because we can check for EXT4_MAP_UNWRITTEN in the
dioread_nolock case instead.

This commit removes EXT4_MAP_UNINIT flag.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/ext4.h

@@ -158,7 +158,6 @@ struct ext4_allocation_request {
 #define EXT4_MAP_MAPPED		(1 << BH_Mapped)
 #define EXT4_MAP_UNWRITTEN	(1 << BH_Unwritten)
 #define EXT4_MAP_BOUNDARY	(1 << BH_Boundary)
-#define EXT4_MAP_UNINIT		(1 << BH_Uninit)
 /* Sometimes (in the bigalloc case, from ext4_da_get_block_prep) the caller of
  * ext4_map_blocks wants to know whether or not the underlying cluster has
  * already been accounted for. EXT4_MAP_FROM_CLUSTER conveys to the caller that
@@ -169,7 +168,7 @@ struct ext4_allocation_request {
 #define EXT4_MAP_FROM_CLUSTER	(1 << BH_AllocFromCluster)
 #define EXT4_MAP_FLAGS		(EXT4_MAP_NEW | EXT4_MAP_MAPPED |\
 				 EXT4_MAP_UNWRITTEN | EXT4_MAP_BOUNDARY |\
-				 EXT4_MAP_UNINIT | EXT4_MAP_FROM_CLUSTER)
+				 EXT4_MAP_FROM_CLUSTER)
 
 struct ext4_map_blocks {
 	ext4_fsblk_t m_pblk;
@@ -2784,10 +2783,9 @@ extern int ext4_mmp_csum_verify(struct super_block *sb,
  * See EXT4_MAP_... to see where this is used.
  */
 enum ext4_state_bits {
-	BH_Uninit	/* blocks are allocated but uninitialized on disk */
+	BH_AllocFromCluster	/* allocated blocks were part of already
-	 = BH_JBDPrivateStart,
-	BH_AllocFromCluster,	/* allocated blocks were part of already
 				 * allocated cluster. */
+	= BH_JBDPrivateStart
 };
 
 /*

fs/ext4/extents.c

@@ -4033,8 +4033,6 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
 		else
 			ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
 		map->m_flags |= EXT4_MAP_UNWRITTEN;
-		if (ext4_should_dioread_nolock(inode))
-			map->m_flags |= EXT4_MAP_UNINIT;
 		goto out;
 	}
 	/* IO end_io complete, convert the filled extent to written */
@@ -4479,8 +4477,6 @@ got_allocated_blocks:
 		 */
 		if ((flags & EXT4_GET_BLOCKS_PRE_IO))
 			set_unwritten = 1;
-		if (ext4_should_dioread_nolock(inode))
-			map->m_flags |= EXT4_MAP_UNINIT;
 	}
 
 	err = 0;

fs/ext4/inode.c

@@ -2126,7 +2126,7 @@ static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
 	struct inode *inode = mpd->inode;
 	struct ext4_map_blocks *map = &mpd->map;
 	int get_blocks_flags;
-	int err;
+	int err, dioread_nolock;
 
 	trace_ext4_da_write_pages_extent(inode, map);
 	/*
@@ -2148,7 +2148,8 @@ static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
 	 */
 	get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
 			   EXT4_GET_BLOCKS_METADATA_NOFAIL;
-	if (ext4_should_dioread_nolock(inode))
+	dioread_nolock = ext4_should_dioread_nolock(inode);
+	if (dioread_nolock)
 		get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
 	if (map->m_flags & (1 << BH_Delay))
 		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
@@ -2156,7 +2157,7 @@ static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
 	err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
 	if (err < 0)
 		return err;
-	if (map->m_flags & EXT4_MAP_UNINIT) {
+	if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
 		if (!mpd->io_submit.io_end->handle &&
 		    ext4_handle_valid(handle)) {
 			mpd->io_submit.io_end->handle = handle->h_rsv_handle;

include/trace/events/ext4.h

@@ -51,7 +51,6 @@ struct extent_status;
 	{ EXT4_MAP_MAPPED,	"M" },			\
 	{ EXT4_MAP_UNWRITTEN,	"U" },			\
 	{ EXT4_MAP_BOUNDARY,	"B" },			\
-	{ EXT4_MAP_UNINIT,	"u" },			\
 	{ EXT4_MAP_FROM_CLUSTER, "C" })
 
 #define show_free_flags(flags) __print_flags(flags, "|",	\