From 2d974619a77f106f3d1341686dea95c0eaad601f Mon Sep 17 00:00:00 2001
From: Qu Wenruo <wqu@suse.com>
Date: Wed, 23 Oct 2019 21:57:26 +0800
Patch-mainline: v5.5-rc1
Git-commit: 2d974619a77f106f3d1341686dea95c0eaad601f
References: bsc#1151910
Subject: [PATCH 1/2] btrfs: volumes: Use more straightforward way to calculate
map length
The old code goes:
offset = logical - em->start;
length = min_t(u64, em->len - offset, length);
Where @length calculation is dependent on offset, it can take reader
several more seconds to find it's just the same code as:
offset = logical - em->start;
length = min_t(u64, em->start + em->len - logical, length);
Use above code to make the length calculate independent from other
variable, thus slightly increase the readability.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/volumes.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index f534a6a5553e..6a0288d17b7d 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5412,7 +5412,7 @@ static int __btrfs_map_block_for_discard(struct btrfs_fs_info *fs_info,
}
offset = logical - em->start;
- length = min_t(u64, em->len - offset, length);
+ length = min_t(u64, em->start + em->len - logical, length);
stripe_len = map->stripe_len;
/*
--
2.24.1