[PATCH v4 qemu-server 09/11] blockdev: change aio on target if io_uring is not default.

Alexandre Derumier alexandre.derumier at groupe-cyllene.com
Tue Mar 11 11:29:03 CET 2025


This was a limitation of drive-mirror, blockdev mirror is able
to reopen image with a different aio.

Do the change when generating the blockdev_format

Signed-off-by: Alexandre Derumier <alexandre.derumier at groupe-cyllene.com>
---
 PVE/QemuServer.pm       |  4 ----
 PVE/QemuServer/Drive.pm | 30 +++---------------------------
 2 files changed, 3 insertions(+), 31 deletions(-)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 63b8f332..d6aa5730 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -7735,8 +7735,6 @@ sub qemu_drive_mirror {
     my $dst_drive = dclone($drive);
     $dst_drive->{file} = $dst_volid;
     $dst_drive->{zeroinit} = 1 if $is_zero_initialized;
-    #improve: if target storage don't support aio uring,change it to default native
-    #and remove clone_disk_check_io_uring()
 
     #add new block device
     my $target_file_blockdev = generate_file_blockdev($storecfg, $dst_drive);
@@ -8109,8 +8107,6 @@ sub clone_disk {
 	    $dst_format = 'raw';
 	    $size = PVE::QemuServer::Drive::TPMSTATE_DISK_SIZE;
 	} else {
-	    clone_disk_check_io_uring($drive, $storecfg, $src_storeid, $storeid, $use_drive_mirror);
-
 	    $size = PVE::Storage::volume_size_info($storecfg, $drive->{file}, 10);
 	}
 	$newvolid = PVE::Storage::vdisk_alloc(
diff --git a/PVE/QemuServer/Drive.pm b/PVE/QemuServer/Drive.pm
index 9fe679dd..5b281616 100644
--- a/PVE/QemuServer/Drive.pm
+++ b/PVE/QemuServer/Drive.pm
@@ -1032,33 +1032,6 @@ my sub drive_uses_cache_direct {
     return $cache_direct;
 }
 
-# Check for bug #4525: drive-mirror will open the target drive with the same aio setting as the
-# source, but some storages have problems with io_uring, sometimes even leading to crashes.
-sub clone_disk_check_io_uring {
-    my ($src_drive, $storecfg, $src_storeid, $dst_storeid, $use_drive_mirror) = @_;
-
-    return if !$use_drive_mirror;
-
-    # Don't complain when not changing storage.
-    # Assume if it works for the source, it'll work for the target too.
-    return if $src_storeid eq $dst_storeid;
-
-    my $src_scfg = PVE::Storage::storage_config($storecfg, $src_storeid);
-    my $dst_scfg = PVE::Storage::storage_config($storecfg, $dst_storeid);
-
-    my $cache_direct = drive_uses_cache_direct($src_drive);
-
-    my $src_uses_io_uring;
-    if ($src_drive->{aio}) {
-	$src_uses_io_uring = $src_drive->{aio} eq 'io_uring';
-    } else {
-	$src_uses_io_uring = storage_allows_io_uring_default($src_scfg, $cache_direct);
-    }
-
-    die "target storage is known to cause issues with aio=io_uring (used by current drive)\n"
-	if $src_uses_io_uring && !storage_allows_io_uring_default($dst_scfg, $cache_direct);
-}
-
 sub generate_blockdev_drive_aio {
     my ($drive, $scfg) = @_;
 
@@ -1077,6 +1050,9 @@ sub generate_blockdev_drive_aio {
 		$aio = "threads";
 	    }
 	}
+    } elsif ($drive->{aio} eq 'io_uring' && !storage_allows_io_uring_default($scfg, $cache_direct)) {
+	#change aio if io_uring is not supported by storage
+	$aio = $cache_direct ? 'native' : 'threads';
     }
     return $aio;
 }
-- 
2.39.5




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