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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>
This commit is contained in:
Nikolay Borisov 2019-01-08 16:53:46 +02:00 committed by David Sterba
parent d00c2d9c76
commit 951e05a904
2 changed files with 4 additions and 2 deletions
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5
fs/btrfs/extent_map.c
View File

@ -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;

1
fs/btrfs/extent_map.h
View File

@ -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 */