From: Anand Jain <anand.jain@oracle.com>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: wqu@suse.com, fdmanana@suse.com, dsterba@suse.com,
linux-btrfs@vger.kernel.org
Subject: [PATCH stable-5.4 3/6] btrfs: volumes: Use more straightforward way to calculate map length
Date: Thu, 8 Oct 2020 18:59:51 +0800 [thread overview]
Message-ID: <b15e98a7c6129f8b5f0a7748061e93865bb944e1.1599750901.git.anand.jain@oracle.com> (raw)
In-Reply-To: <cover.1599750901.git.anand.jain@oracle.com>
From: Qu Wenruo <wqu@suse.com>
commit 2d974619a77f106f3d1341686dea95c0eaad601f upstream.
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>
Signed-off-by: Anand Jain <anand.jain@oracle.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 196ddbcd2936..1dba45d43485 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5712,7 +5712,7 @@ 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;
/*
--
2.25.1
next prev parent reply other threads:[~2020-10-08 11:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 10:59 [PATCH stable-5.4 0/6] backport fixes for xfstests btrfs/199,200,203,204 Anand Jain
2020-10-08 10:59 ` [PATCH stable-5.4 1/6] Btrfs: send, allow clone operations within the same file Anand Jain
2020-10-08 10:59 ` [PATCH stable-5.4 2/6] Btrfs: send, fix emission of invalid " Anand Jain
2020-10-08 10:59 ` Anand Jain [this message]
2020-10-08 10:59 ` [PATCH stable-5.4 4/6] btrfs: Ensure we trim ranges across block group boundary Anand Jain
2020-10-08 10:59 ` [PATCH stable-5.4 5/6] btrfs: fix RWF_NOWAIT write not failling when we need to cow Anand Jain
2020-10-08 10:59 ` [PATCH stable-5.4 6/6] btrfs: allow btrfs_truncate_block() to fallback to nocow for data space reservation Anand Jain
2020-10-09 14:06 ` Greg KH
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