Dario Faggioli
38f7ac0eef
- [JIRA] (SLE-20965) Make QEMU guests more failsafe when resizing
SCSI passthrough disks
* Patches added:
scsi-generic-replace-logical-block-count.patch
OBS-URL: https://build.opensuse.org/request/show/941797
OBS-URL: https://build.opensuse.org/package/show/Virtualization/qemu?expand=0&rev=682
104 lines
3.7 KiB
Diff
104 lines
3.7 KiB
Diff
From: Lin Ma <lma@suse.com>
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Date: Sat, 20 Nov 2021 18:05:57 +0800
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Subject: scsi-generic: replace logical block count of response of READ
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CAPACITY
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Git-commit: 0000000000000000000000000000000000000000
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References: [SUSE-JIRA] (SLE-20965)
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While using SCSI passthrough, Following scenario makes qemu doesn't
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realized the capacity change of remote scsi target:
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1. online resize the scsi target.
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2. issue 'rescan-scsi-bus.sh -s ...' in host.
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3. issue 'rescan-scsi-bus.sh -s ...' in vm.
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In above scenario I used to experienced errors while accessing the
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additional disk space in vm. I think the reasonable operations should
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be:
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1. online resize the scsi target.
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2. issue 'rescan-scsi-bus.sh -s ...' in host.
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3. issue 'block_resize' via qmp to notify qemu.
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4. issue 'rescan-scsi-bus.sh -s ...' in vm.
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The errors disappear once I notify qemu by block_resize via qmp.
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So this patch replaces the number of logical blocks of READ CAPACITY
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response from scsi target by qemu's bs->total_sectors. If the user in
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vm wants to access the additional disk space, The administrator of
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host must notify qemu once resizeing the scsi target.
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Bonus is that domblkinfo of libvirt can reflect the consistent capacity
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information between host and vm in case of missing block_resize in qemu.
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E.g:
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...
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<disk type='block' device='lun'>
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<driver name='qemu' type='raw'/>
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<source dev='/dev/sdc' index='1'/>
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<backingStore/>
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<target dev='sda' bus='scsi'/>
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<alias name='scsi0-0-0-0'/>
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<address type='drive' controller='0' bus='0' target='0' unit='0'/>
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</disk>
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...
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Before:
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1. online resize the scsi target.
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2. host:~ # rescan-scsi-bus.sh -s /dev/sdc
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3. guest:~ # rescan-scsi-bus.sh -s /dev/sda
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4 host:~ # virsh domblkinfo --domain $DOMAIN --human --device sda
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Capacity: 4.000 GiB
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Allocation: 0.000 B
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Physical: 8.000 GiB
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5. guest:~ # lsblk /dev/sda
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NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
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sda 8:0 0 8G 0 disk
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└─sda1 8:1 0 2G 0 part
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After:
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1. online resize the scsi target.
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2. host:~ # rescan-scsi-bus.sh -s /dev/sdc
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3. guest:~ # rescan-scsi-bus.sh -s /dev/sda
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4 host:~ # virsh domblkinfo --domain $DOMAIN --human --device sda
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Capacity: 4.000 GiB
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Allocation: 0.000 B
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Physical: 8.000 GiB
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5. guest:~ # lsblk /dev/sda
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NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
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sda 8:0 0 4G 0 disk
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└─sda1 8:1 0 2G 0 part
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Signed-off-by: Lin Ma <lma@suse.com>
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---
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hw/scsi/scsi-generic.c | 10 ++++++++--
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1 file changed, 8 insertions(+), 2 deletions(-)
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diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
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index 0306ccc7b1e4827a67aaed926f93..343b51c2c0ab5dc7fb792aeb6458 100644
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--- a/hw/scsi/scsi-generic.c
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+++ b/hw/scsi/scsi-generic.c
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@@ -315,11 +315,17 @@ static void scsi_read_complete(void * opaque, int ret)
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if (r->req.cmd.buf[0] == READ_CAPACITY_10 &&
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(ldl_be_p(&r->buf[0]) != 0xffffffffU || s->max_lba == 0)) {
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s->blocksize = ldl_be_p(&r->buf[4]);
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- s->max_lba = ldl_be_p(&r->buf[0]) & 0xffffffffULL;
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+ BlockBackend *blk = s->conf.blk;
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+ BlockDriverState *bs = blk_bs(blk);
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+ s->max_lba = bs->total_sectors - 1;
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+ stl_be_p(&r->buf[0], s->max_lba);
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} else if (r->req.cmd.buf[0] == SERVICE_ACTION_IN_16 &&
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(r->req.cmd.buf[1] & 31) == SAI_READ_CAPACITY_16) {
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s->blocksize = ldl_be_p(&r->buf[8]);
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- s->max_lba = ldq_be_p(&r->buf[0]);
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+ BlockBackend *blk = s->conf.blk;
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+ BlockDriverState *bs = blk_bs(blk);
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+ s->max_lba = bs->total_sectors - 1;
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+ stq_be_p(&r->buf[0], s->max_lba);
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}
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blk_set_guest_block_size(s->conf.blk, s->blocksize);
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