Commit 7c159037 authored by Tony Breeds's avatar Tony Breeds Committed by Kevin Wolf

block/raw-posix: use seek_hole ahead of fiemap

try_fiemap() uses FIEMAP_FLAG_SYNC which has a significant performance
impact.

Prefer seek_hole() over fiemap() to avoid this impact where possible.
seek_hole is more widely used and, arguably, has potential to be
optimised in the kernel.
Reported-By: default avatarMichael Steffens <michael_steffens@posteo.de>
Signed-off-by: default avatarTony Breeds <tony@bakeyournoodle.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Max Reitz <mreitz@redhat.com>
Cc: Pádraig Brady <pbrady@redhat.com>
Cc: Eric Blake <eblake@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 38c4d0ae
......@@ -1571,9 +1571,9 @@ static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
start = sector_num * BDRV_SECTOR_SIZE;
ret = try_fiemap(bs, start, &data, &hole, nb_sectors, pnum);
ret = try_seek_hole(bs, start, &data, &hole, pnum);
if (ret < 0) {
ret = try_seek_hole(bs, start, &data, &hole, pnum);
ret = try_fiemap(bs, start, &data, &hole, nb_sectors, pnum);
if (ret < 0) {
/* Assume everything is allocated. */
data = 0;
......
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