From 951e05a90469e29326715e7e3aefd4680748b4fa Mon Sep 17 00:00:00 2001
From: Nikolay Borisov <nborisov@suse.com>
Date: Tue, 8 Jan 2019 16:53:46 +0200
Subject: [PATCH] btrfs: Remove impossible condition from mergable_maps
We can never have extents marked as EXTENT_MAP_DELALLOC since this
value is only ever used by btrfs_get_extent_fiemap. In this case the
extent map is created by btrfs_get_extent_fiemap and is never really
published, this flag is used to return the corresponding userspace one.
Considering this, it's pointless having a check for EXTENT_MAP_DELALLOC
in mergable_maps. Just remove it.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/extent_map.c | 5 +++--
fs/btrfs/extent_map.h | 1 +
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index a042a193c120..928f729c55ba 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -210,6 +210,9 @@ static int mergable_maps(struct extent_map *prev, struct extent_map *next)
if (!list_empty(&prev->list) || !list_empty(&next->list))
return 0;
+ ASSERT(next->block_start != EXTENT_MAP_DELALLOC &&
+ prev->block_start != EXTENT_MAP_DELALLOC);
+
if (extent_map_end(prev) == next->start &&
prev->flags == next->flags &&
prev->bdev == next->bdev &&
@@ -217,8 +220,6 @@ static int mergable_maps(struct extent_map *prev, struct extent_map *next)
prev->block_start == EXTENT_MAP_HOLE) ||
(next->block_start == EXTENT_MAP_INLINE &&
prev->block_start == EXTENT_MAP_INLINE) ||
- (next->block_start == EXTENT_MAP_DELALLOC &&
- prev->block_start == EXTENT_MAP_DELALLOC) ||
(next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
next->block_start == extent_map_block_end(prev)))) {
return 1;
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index ef05a0121652..473f039fcd7c 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -9,6 +9,7 @@
#define EXTENT_MAP_LAST_BYTE ((u64)-4)
#define EXTENT_MAP_HOLE ((u64)-3)
#define EXTENT_MAP_INLINE ((u64)-2)
+/* used only during fiemap calls */
#define EXTENT_MAP_DELALLOC ((u64)-1)
/* bits for the extent_map::flags field */