[Qemu-devel] "block: use aio_bh_schedule_oneshot" breaks ibm-vscsi

[Alexey Kardashevskiy <aik@ozlabs.ru>]

Hi,

I just discovered that fffb6e12233002c26c0ee9ff92fa87927cd779f2 broke
ibm-vscsi, the guest booting stops (I waited for a minute) at:

[    0.809286] ibmvscsi 71000001: SRP_VERSION: 16.a
[    0.809766] ibmvscsi 71000001: Maximum ID: 64 Maximum LUN: 32 Maximum Channel: 3
[    0.810059] scsi host0: IBM POWER Virtual SCSI Adapter 1.5.9
[    0.810634] ibmvscsi 71000001: partner initialization complete
[    0.810999] ibmvscsi 71000001: host srp version: 16.a, host partition qemu (0), OS 2, max io 2097152
[    0.811507] ibmvscsi 71000001: sent SRP login
[    0.811705] ibmvscsi 71000001: SRP_LOGIN succeeded
[    0.824062] scsi 0:0:0:0: Direct-Access     QEMU     QEMU HARDDISK    2.5+ PQ: 0 ANSI: 5
[    1.018526] sd 0:0:0:0: Attached scsi generic sg0 type 0
[    1.019352] sd 0:0:0:0: [sda] 67108864 512-byte logical blocks: (34.4 GB/32.0 GiB)
[    1.020274] sd 0:0:0:0: [sda] Write Protect is off
[    1.020667] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[    1.023390]  sda: sda1 sda2 sda3
[    1.025819] sd 0:0:0:0: [sda] Attached SCSI disk


When I switch to virtio-vscsi, I get a bit further:

Begin: Loading essential drivers ... done.
Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done.
Begin: Running /scripts/local-premount ... done.
Begin: Will now check root file system ... fsck from util-linux 2.27.1
[/sbin/fsck.ext4 (1) -- /dev/sda2] fsck.ext4 -a -C0 /dev/sda2
fsck.ext4: Read-only file system while trying to open /dev/sda2
Disk write-protected; use the -n option to do a read-only
check of the device.
fsck exited with status code 8
done.
Warning: File system check failed but did not detect errors

and then I get login prompt.


With reverted fffb6e12233002c26c0ee9ff92fa87927cd779f2, virtio-vscsi behaves
the same (so I assume fffb6e122 does not affect it) and ibm-vscsi behaves nicely:

Begin: Loading essential drivers ... done.
Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done.
Begin: Running /scripts/local-premount ... done.
Begin: Will now check root file system ... fsck from util-linux 2.27.1
[/sbin/fsck.ext4 (1) -- /dev/sda2] fsck.ext4 -a -C0 /dev/sda2
/dev/sda2: clean, 66846/2011296 files, 574929/8034048 blocks
done.
[    0.996954] EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: (null)
done.

and then I get login prompt.


fffb6e12233002c26c0ee9ff92fa87927cd779f2 is:
===
block: use aio_bh_schedule_oneshot

This simplifies bottom half handlers by removing calls to qemu_bh_delete and
thus removing the need to stash the bottom half pointer in the opaque
datum.
===

Any clues what is wrong? Thanks.


---
Alexey