btrfs: cleanup calculation of lockend in lock_and_cleanup_extent_if_need()

We're just doing rounding up to sectorsize to calculate the lockend.
There is no need to do the unnecessary length calculation, just direct
round_up() is enough.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 4507c3d..de14ed4 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1477,9 +1477,7 @@ lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
        int ret = 0;
 
        start_pos = round_down(pos, fs_info->sectorsize);
-       last_pos = start_pos
-               + round_up(pos + write_bytes - start_pos,
-                          fs_info->sectorsize) - 1;
+       last_pos = round_up(pos + write_bytes, fs_info->sectorsize) - 1;
 
        if (start_pos < inode->vfs_inode.i_size) {
                struct btrfs_ordered_extent *ordered;