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>

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index a042a193c12085b63e7b1437e97e4d388f14b36b..928f729c55baf61b02e7a4fb612eaebffbdc2d50 100644 (file)
--- 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 ef05a0121652e8f54d9e29d21445e2dd1cdb936e..473f039fcd7c783f222a1be18e19c5b62b0e9271 100644 (file)
--- 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 */