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Re: [PATCH v8 2/8] block: consolidate blocksize properties consistency checks



Am 29.05.2020 um 12:56 hat Roman Kagan geschrieben:
> On Fri, May 29, 2020 at 11:53:26AM +0200, Markus Armbruster wrote:
> > Roman Kagan <rvkagan@xxxxxxxxxxxxxx> writes:
> > 
> > > Several block device properties related to blocksize configuration must
> > > be in certain relationship WRT each other: physical block must be no
> > > smaller than logical block; min_io_size, opt_io_size, and
> > > discard_granularity must be a multiple of a logical block.
> > >
> > > To ensure these requirements are met, add corresponding consistency
> > > checks to blkconf_blocksizes, adjusting its signature to communicate
> > > possible error to the caller.  Also remove the now redundant consistency
> > > checks from the specific devices.
> > >
> > > Signed-off-by: Roman Kagan <rvkagan@xxxxxxxxxxxxxx>
> > > Reviewed-by: Eric Blake <eblake@xxxxxxxxxx>
> > > Reviewed-by: Paul Durrant <paul@xxxxxxx>
> > > ---
> > >  include/hw/block/block.h   |  2 +-
> > >  hw/block/block.c           | 30 +++++++++++++++++++++++++++++-
> > >  hw/block/fdc.c             |  5 ++++-
> > >  hw/block/nvme.c            |  5 ++++-
> > >  hw/block/swim.c            |  5 ++++-
> > >  hw/block/virtio-blk.c      |  7 +------
> > >  hw/block/xen-block.c       |  6 +-----
> > >  hw/ide/qdev.c              |  5 ++++-
> > >  hw/scsi/scsi-disk.c        | 12 +++++-------
> > >  hw/usb/dev-storage.c       |  5 ++++-
> > >  tests/qemu-iotests/172.out |  2 +-
> > >  11 files changed, 58 insertions(+), 26 deletions(-)
> > >
> > > diff --git a/include/hw/block/block.h b/include/hw/block/block.h
> > > index d7246f3862..784953a237 100644
> > > --- a/include/hw/block/block.h
> > > +++ b/include/hw/block/block.h
> > > @@ -87,7 +87,7 @@ bool blk_check_size_and_read_all(BlockBackend *blk, 
> > > void *buf, hwaddr size,
> > >  bool blkconf_geometry(BlockConf *conf, int *trans,
> > >                        unsigned cyls_max, unsigned heads_max, unsigned 
> > > secs_max,
> > >                        Error **errp);
> > > -void blkconf_blocksizes(BlockConf *conf);
> > > +bool blkconf_blocksizes(BlockConf *conf, Error **errp);
> > >  bool blkconf_apply_backend_options(BlockConf *conf, bool readonly,
> > >                                     bool resizable, Error **errp);
> > >  
> > > diff --git a/hw/block/block.c b/hw/block/block.c
> > > index bf56c7612b..b22207c921 100644
> > > --- a/hw/block/block.c
> > > +++ b/hw/block/block.c
> > > @@ -61,7 +61,7 @@ bool blk_check_size_and_read_all(BlockBackend *blk, 
> > > void *buf, hwaddr size,
> > >      return true;
> > >  }
> > >  
> > > -void blkconf_blocksizes(BlockConf *conf)
> > > +bool blkconf_blocksizes(BlockConf *conf, Error **errp)
> > >  {
> > >      BlockBackend *blk = conf->blk;
> > >      BlockSizes blocksizes;
> > > @@ -83,6 +83,34 @@ void blkconf_blocksizes(BlockConf *conf)
> > >              conf->logical_block_size = BDRV_SECTOR_SIZE;
> > >          }
> > >      }
> > > +
> > > +    if (conf->logical_block_size > conf->physical_block_size) {
> > > +        error_setg(errp,
> > > +                   "logical_block_size > physical_block_size not 
> > > supported");
> > > +        return false;
> > > +    }
> > 
> > Pardon me if this has been answered already for prior revisions: do we
> > really support physical block sizes that are not a multiple of the
> > logical block size?
> 
> Both physical and logical block sizes are required to be powers of two,
> so the former is certain to be a multiple of the latter.
> 
> > > +
> > > +    if (!QEMU_IS_ALIGNED(conf->min_io_size, conf->logical_block_size)) {
> > > +        error_setg(errp,
> > > +                   "min_io_size must be a multiple of 
> > > logical_block_size");
> > > +        return false;
> > > +    }
> > > +
> > > +    if (!QEMU_IS_ALIGNED(conf->opt_io_size, conf->logical_block_size)) {
> > > +        error_setg(errp,
> > > +                   "opt_io_size must be a multiple of 
> > > logical_block_size");
> > > +        return false;
> > > +    }
> > > +
> > > +    if (conf->discard_granularity != -1 &&
> > > +        !QEMU_IS_ALIGNED(conf->discard_granularity,
> > > +                         conf->logical_block_size)) {
> > > +        error_setg(errp, "discard_granularity must be "
> > > +                   "a multiple of logical_block_size");
> > > +        return false;
> > > +    }
> > > +
> > > +    return true;
> > >  }
> > >  
> > >  bool blkconf_apply_backend_options(BlockConf *conf, bool readonly,
> > > diff --git a/hw/block/fdc.c b/hw/block/fdc.c
> > > index c5fb9d6ece..8eda572ef4 100644
> > > --- a/hw/block/fdc.c
> > > +++ b/hw/block/fdc.c
> > > @@ -554,7 +554,10 @@ static void floppy_drive_realize(DeviceState *qdev, 
> > > Error **errp)
> > >          read_only = !blk_bs(dev->conf.blk) || 
> > > blk_is_read_only(dev->conf.blk);
> > >      }
> > >  
> > > -    blkconf_blocksizes(&dev->conf);
> > > +    if (!blkconf_blocksizes(&dev->conf, errp)) {
> > > +        return;
> > > +    }
> > > +
> > >      if (dev->conf.logical_block_size != 512 ||
> > >          dev->conf.physical_block_size != 512)
> > >      {
> > > diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> > > index 2f3100e56c..672650e162 100644
> > > --- a/hw/block/nvme.c
> > > +++ b/hw/block/nvme.c
> > > @@ -1390,7 +1390,10 @@ static void nvme_realize(PCIDevice *pci_dev, Error 
> > > **errp)
> > >          host_memory_backend_set_mapped(n->pmrdev, true);
> > >      }
> > >  
> > > -    blkconf_blocksizes(&n->conf);
> > > +    if (!blkconf_blocksizes(&n->conf, errp)) {
> > > +        return;
> > > +    }
> > > +
> > >      if (!blkconf_apply_backend_options(&n->conf, 
> > > blk_is_read_only(n->conf.blk),
> > >                                         false, errp)) {
> > >          return;
> > > diff --git a/hw/block/swim.c b/hw/block/swim.c
> > > index 8f124782f4..74f56e8f46 100644
> > > --- a/hw/block/swim.c
> > > +++ b/hw/block/swim.c
> > > @@ -189,7 +189,10 @@ static void swim_drive_realize(DeviceState *qdev, 
> > > Error **errp)
> > >          assert(ret == 0);
> > >      }
> > >  
> > > -    blkconf_blocksizes(&dev->conf);
> > > +    if (!blkconf_blocksizes(&dev->conf, errp)) {
> > > +        return;
> > > +    }
> > > +
> > >      if (dev->conf.logical_block_size != 512 ||
> > >          dev->conf.physical_block_size != 512)
> > >      {
> > > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> > > index 413083e62f..4ffdb130be 100644
> > > --- a/hw/block/virtio-blk.c
> > > +++ b/hw/block/virtio-blk.c
> > > @@ -1162,12 +1162,7 @@ static void virtio_blk_device_realize(DeviceState 
> > > *dev, Error **errp)
> > >          return;
> > >      }
> > >  
> > > -    blkconf_blocksizes(&conf->conf);
> > > -
> > > -    if (conf->conf.logical_block_size >
> > > -        conf->conf.physical_block_size) {
> > > -        error_setg(errp,
> > > -                   "logical_block_size > physical_block_size not 
> > > supported");
> > > +    if (!blkconf_blocksizes(&conf->conf, errp)) {
> > >          return;
> > >      }
> > >  
> > > diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
> > > index 570489d6d9..e17fec50e1 100644
> > > --- a/hw/block/xen-block.c
> > > +++ b/hw/block/xen-block.c
> > > @@ -239,11 +239,7 @@ static void xen_block_realize(XenDevice *xendev, 
> > > Error **errp)
> > >          return;
> > >      }
> > >  
> > > -    blkconf_blocksizes(conf);
> > > -
> > > -    if (conf->logical_block_size > conf->physical_block_size) {
> > > -        error_setg(
> > > -            errp, "logical_block_size > physical_block_size not 
> > > supported");
> > > +    if (!blkconf_blocksizes(conf, errp)) {
> > >          return;
> > >      }
> > >  
> > > diff --git a/hw/ide/qdev.c b/hw/ide/qdev.c
> > > index 06b11583f5..b4821b2403 100644
> > > --- a/hw/ide/qdev.c
> > > +++ b/hw/ide/qdev.c
> > > @@ -187,7 +187,10 @@ static void ide_dev_initfn(IDEDevice *dev, 
> > > IDEDriveKind kind, Error **errp)
> > >          return;
> > >      }
> > >  
> > > -    blkconf_blocksizes(&dev->conf);
> > > +    if (!blkconf_blocksizes(&dev->conf, errp)) {
> > > +        return;
> > > +    }
> > > +
> > >      if (dev->conf.logical_block_size != 512) {
> > >          error_setg(errp, "logical_block_size must be 512 for IDE");
> > >          return;
> > > diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
> > > index 387503e11b..8ce68a9dd6 100644
> > > --- a/hw/scsi/scsi-disk.c
> > > +++ b/hw/scsi/scsi-disk.c
> > > @@ -2346,12 +2346,7 @@ static void scsi_realize(SCSIDevice *dev, Error 
> > > **errp)
> > >          return;
> > >      }
> > >  
> > > -    blkconf_blocksizes(&s->qdev.conf);
> > > -
> > > -    if (s->qdev.conf.logical_block_size >
> > > -        s->qdev.conf.physical_block_size) {
> > > -        error_setg(errp,
> > > -                   "logical_block_size > physical_block_size not 
> > > supported");
> > > +    if (!blkconf_blocksizes(&s->qdev.conf, errp)) {
> > >          return;
> > >      }
> > >  
> > > @@ -2436,7 +2431,9 @@ static void scsi_hd_realize(SCSIDevice *dev, Error 
> > > **errp)
> > >      if (s->qdev.conf.blk) {
> > >          ctx = blk_get_aio_context(s->qdev.conf.blk);
> > >          aio_context_acquire(ctx);
> > > -        blkconf_blocksizes(&s->qdev.conf);
> > > +        if (!blkconf_blocksizes(&s->qdev.conf, errp)) {
> > > +            goto out;
> > > +        }
> > >      }
> > >      s->qdev.blocksize = s->qdev.conf.logical_block_size;
> > >      s->qdev.type = TYPE_DISK;
> > > @@ -2444,6 +2441,7 @@ static void scsi_hd_realize(SCSIDevice *dev, Error 
> > > **errp)
> > >          s->product = g_strdup("QEMU HARDDISK");
> > >      }
> > >      scsi_realize(&s->qdev, errp);
> > > +out:
> > >      if (ctx) {
> > >          aio_context_release(ctx);
> > >      }
> > > diff --git a/hw/usb/dev-storage.c b/hw/usb/dev-storage.c
> > > index 4eba47538d..de461f37bd 100644
> > > --- a/hw/usb/dev-storage.c
> > > +++ b/hw/usb/dev-storage.c
> > > @@ -599,7 +599,10 @@ static void usb_msd_storage_realize(USBDevice *dev, 
> > > Error **errp)
> > >          return;
> > >      }
> > >  
> > > -    blkconf_blocksizes(&s->conf);
> > > +    if (!blkconf_blocksizes(&s->conf, errp)) {
> > > +        return;
> > > +    }
> > > +
> > >      if (!blkconf_apply_backend_options(&s->conf, blk_is_read_only(blk), 
> > > true,
> > >                                         errp)) {
> > >          return;
> > > diff --git a/tests/qemu-iotests/172.out b/tests/qemu-iotests/172.out
> > > index 7abbe82427..59cc70aebb 100644
> > > --- a/tests/qemu-iotests/172.out
> > > +++ b/tests/qemu-iotests/172.out
> > > @@ -1204,7 +1204,7 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 
> > > -device floppy,drive=none0,physica
> > >                  drive-type = "144"
> > >  
> > >  Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device 
> > > floppy,drive=none0,logical_block_size=4096
> > > -QEMU_PROG: -device floppy,drive=none0,logical_block_size=4096: Physical 
> > > and logical block size must be 512 for floppy
> > > +QEMU_PROG: -device floppy,drive=none0,logical_block_size=4096: 
> > > logical_block_size > physical_block_size not supported
> > >  
> > >  Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device 
> > > floppy,drive=none0,physical_block_size=1024
> > >  QEMU_PROG: -device floppy,drive=none0,physical_block_size=1024: Physical 
> > > and logical block size must be 512 for floppy
> > 
> > This no longer exercises floppy_drive_realize()'s check of
> > logical_block_size:
> > 
> >     if (dev->conf.logical_block_size != 512 ||
> >         dev->conf.physical_block_size != 512)
> 
> Right, this check of logical_block_size here becomes redundant now,
> because eariler it's verified to be no less than 512 and no more than
> physical_block_size, which is required to be 512 here.  I thought it
> made no harm to leave it here as it was, and decided not to bother
> replacing it with a comment as to why the condition is known to be true.
> 
> >     {
> >         error_setg(errp, "Physical and logical block size must "
> >                    "be 512 for floppy");
> >         return;
> >     }
> > 
> > Please update the test.
> 
> The test still makes sense, it just triggers another assertion now.  How
> do you suggest to update it?

I guess we could just add another case with physical=logical=4096 so we
test both the original floppy check (with the new case) and your new
check (with the existing case).

But as you explained above, it's kind of redundant and we can't tell
from the result whether the logical or the physical check failed (they
are then both unsuitable for floppy), so maybe adding that case is
rather pointless.

Kevin




 


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