Commit Graph

670 Commits

Author SHA1 Message Date
Anthony Liguori a9b670b139 Merge remote-tracking branch 'bonzini/scsi-next' into staging
* bonzini/scsi-next:
  virtio-scsi: add backwards-compatibility properties for 1.1 and earlier machines
  iscsi: fix races between task completion and abort
  iscsi: simplify iscsi_schedule_bh
  iscsi: move iscsi_schedule_bh and iscsi_readv_writev_bh_cb
  Revert "iscsi: Fix NULL dereferences / races between task completion and abort"
2012-08-22 13:31:17 -05:00
Anthony Liguori 7b2f89c435 Merge remote-tracking branch 'kwolf/for-anthony' into staging
* kwolf/for-anthony:
  virtio-blk: hide VIRTIO_BLK_F_CONFIG_WCE from old machine types
  Documentation: Warn against qemu-img on active image
  vmdk: Read footer for streamOptimized images
  vmdk: Fix header structure

Conflicts:
	hw/virtio-blk.c
2012-08-22 13:01:05 -05:00
Jim Meyering a7e47d4bfc sheepdog: don't leak socket file descriptor upon connection failure
Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-08-22 10:47:14 -05:00
Paolo Bonzini 1bd075f29e iscsi: fix races between task completion and abort
This patch fixes two main issues with block/iscsi.c:

1) iscsi_task_mgmt_abort_task_async calls iscsi_scsi_task_cancel which
was also directly called in iscsi_aio_cancel

2) a race between task completion and task abortion could happen cause
the scsi_free_scsi_task were done before iscsi_schedule_bh has finished.
To fix this, all the freeing of IscsiTasks and releasing of the AIOCBs
is centralized in iscsi_bh_cb, independent of whether the SCSI command
has completed or was cancelled.

3) iscsi_aio_cancel was not synchronously waiting for the end of the
command.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-20 15:58:47 +02:00
Paolo Bonzini cfb3f5064a iscsi: simplify iscsi_schedule_bh
It is always used with the same callback, remove the argument.  And
its return value is never used, assume allocation succeeds.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-20 15:58:47 +02:00
Paolo Bonzini 27cbd828c6 iscsi: move iscsi_schedule_bh and iscsi_readv_writev_bh_cb
Put these functions at the beginning, to avoid forward references
in the next patches.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-20 15:58:47 +02:00
Paolo Bonzini b209091957 Revert "iscsi: Fix NULL dereferences / races between task completion and abort"
This reverts commit 64e69e8092.  The commit
returned immediately from iscsi_aio_cancel, risking corruption in case the
following happens:

    guest                  qemu                 target
  =========================================================================
    send write 1 -------->
                           send write 1 -------->
    cancel write 1 ------>
                           cancel write 1 ------>
       <------------------ cancellation processed
    send write 2 -------->
                           send write 2 -------->
                               <---------------- completed write 2
       <------------------ completed write 2
                               <---------------- completed write 1
                               <---------------- cancellation not done

Here, the guest would see write 2 superseding write 1, when in fact the
outcome could have been the opposite.  The right behavior is to return
only after the target says whether the cancellation was done or not, and
it will be implemented by the next three patches.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-20 15:50:45 +02:00
Kevin Wolf 65bd155c73 vmdk: Read footer for streamOptimized images
The footer takes precedence over the header when it exists. It contains
the real grain directory offset that is missing in the header. Without
this patch, streamOptimized images with a footer cannot be read.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
2012-08-17 13:27:02 +02:00
Kevin Wolf 7a736bfa4e vmdk: Fix header structure
Commit bb45ded9 swapped gd_offset and rgd_offset. This is wrong.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-17 11:14:19 +02:00
Stefan Priebe 64e69e8092 iscsi: Fix NULL dereferences / races between task completion and abort
Signed-off-by: Stefan Priebe <s.priebe@profihost.ag>
Acked-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-15 13:16:22 +02:00
Corey Bryant 2e1e79dae7 block: Convert close calls to qemu_close
This patch converts all block layer close calls, that correspond
to qemu_open calls, to qemu_close.

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-15 10:48:57 +02:00
Corey Bryant 6165f4d85d block: Convert open calls to qemu_open
This patch converts all block layer open calls to qemu_open.

Note that this adds the O_CLOEXEC flag to the changed open paths
when the O_CLOEXEC macro is defined.

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-15 10:48:57 +02:00
Corey Bryant e174082835 block: Prevent detection of /dev/fdset/ as floppy
Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-15 10:48:57 +02:00
Anthony Liguori 53810bab3a Merge remote-tracking branch 'kwolf/for-anthony' into staging
* kwolf/for-anthony:
  qemu-iotests: skip 039 with ./check -nocache
  block: add BLOCK_O_CHECK for qemu-img check
  qcow2: mark image clean after repair succeeds
  qed: mark image clean after repair succeeds
  blockdev: flip default cache mode from writethrough to writeback
  virtio-blk: disable write cache if not negotiated
  virtio-blk: support VIRTIO_BLK_F_CONFIG_WCE
  qemu-iotests: Save some sed processes
  ahci: Fix sglist memleak in ahci_dma_rw_buf()
  ahci: Fix ahci cdrom read corruptions for reads > 128k
  virtio-blk: fix use-after-free while handling scsi commands
2012-08-11 19:48:50 -05:00
Anthony Liguori 312942619a Merge remote-tracking branch 'bonzini/scsi-next' into staging
* bonzini/scsi-next:
  scsi-disk: add support for the UNMAP command
  scsi-disk: improve out-of-range LBA detection for WRITE SAME
  scsi-disk: more assertions and resets for aiocb
  virtio-scsi: do not compare 32-bit QEMU tags against 64-bit virtio-scsi tags
  iscsi: Pick default initiator-name based on the name of the VM
  iscsi: reorganize code for parse_initiator_name
  iscsi: do not leak initiator_name
2012-08-11 17:11:23 -05:00
Stefan Hajnoczi 058f8f16db block: add BLOCK_O_CHECK for qemu-img check
Image formats with a dirty bit, like qed and qcow2, repair dirty image
files upon open with BDRV_O_RDWR.  Performing automatic repair when
qemu-img check runs is not ideal because the bdrv_open() call repairs
the image before the actual bdrv_check() call from qemu-img.c.

Fix this "double repair" since it leads to confusing output from
qemu-img check.  Tell the block driver that this image is being opened
just for bdrv_check().  This skips automatic repair and qemu-img.c can
invoke it manually with bdrv_check().

Update the golden output for qemu-iotests 039 to reflect the new
qemu-img check output.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-10 10:25:12 +02:00
Stefan Hajnoczi acbe59829e qcow2: mark image clean after repair succeeds
The dirty bit is cleared after image repair succeeds in qcow2_open().
Move this into qcow2_check() so that all callers benefit from this
behavior when fix mode is enabled.

This is necessary so qemu-img check can call .bdrv_check() and mark the
image clean.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-10 10:25:12 +02:00
Stefan Hajnoczi b10170aca0 qed: mark image clean after repair succeeds
The dirty bit is cleared after image repair succeeds in qed_open().
Move this into qed_check() so that all callers benefit from this
behavior when fix=true.

This is necessary so qemu-img check can call .bdrv_check() and mark the
image clean.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-10 10:25:12 +02:00
Ronnie Sahlberg 31459f463a iscsi: Pick default initiator-name based on the name of the VM
This patch updates the iscsi layer to automatically pick a 'unique'
initiator-name based on the name of the vm in case the user has not set
an explicit iqn-name to use.

Create a new function qemu_get_vm_name() that returns the name of the VM,
if specified.

This way we can thus create default names to use as the initiator name
based on the guest session.

If the VM is not named via the '-name' command line argument, the iscsi
initiator-name used wiull simply be

    iqn.2008-11.org.linux-kvm

If a name for the VM was specified with the '-name' option, iscsi will
use a default initiatorname of

    iqn.2008-11.org.linux-kvm:<name>

These names are just the default iscsi initiator name that qemu will
generate/use only when the user has not set an explicit initiator name
via the commandlines or config files.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
2012-08-09 15:04:09 +02:00
Paolo Bonzini f2ef4a6dd9 iscsi: reorganize code for parse_initiator_name
Merge the occurrences of the "iqn.2008-11.org.linux-kvm" string
to avoid duplication.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-08 14:51:59 +02:00
Paolo Bonzini b93c94f7ec iscsi: do not leak initiator_name
The argument of iscsi_create_context is never freed by libiscsi,
which in fact calls strdup on it.  Avoid a leak.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-08-08 14:51:59 +02:00
Stefan Hajnoczi bfe8043e92 qcow2: implement lazy refcounts
Lazy refcounts is a performance optimization for qcow2 that postpones
refcount metadata updates and instead marks the image dirty.  In the
case of crash or power failure the image will be left in a dirty state
and repaired next time it is opened.

Reducing metadata I/O is important for cache=writethrough and
cache=directsync because these modes guarantee that data is on disk
after each write (hence we cannot take advantage of caching updates in
RAM).  Refcount metadata is not needed for guest->file block address
translation and therefore does not need to be on-disk at the time of
write completion - this is the motivation behind the lazy refcount
optimization.

The lazy refcount optimization must be enabled at image creation time:

  qemu-img create -f qcow2 -o compat=1.1,lazy_refcounts=on a.qcow2 10G
  qemu-system-x86_64 -drive if=virtio,file=a.qcow2,cache=writethrough

Update qemu-iotests 031 and 036 since the extension header size changes
when we add feature bit table entries.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-06 22:39:14 +02:00
Stefan Hajnoczi c61d0004bc qcow2: introduce dirty bit
This patch adds an incompatible feature bit to mark images that have not
been closed cleanly.  When a dirty image file is opened a consistency
check and repair is performed.

Update qemu-iotests 031 and 036 since the extension header size changes
when we add feature bit table entries.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-08-06 22:39:14 +02:00
Markus Armbruster 4480e0f924 vvfat: Do not clobber the user's geometry
vvfat creates a virtual VFAT filesystem with a certain logical
geometry that depends on its options.  It sets the "geometry hint" to
this geometry.  It is the only block driver to do this.

The geometry hint is about about *physical* geometry, and used only by
certain hard disk device models.

vvfat's hint is normally invisible for device models, because
bdrv_open() puts a raw format on top of vvfat's fat protocol.  That
raw format is where drive_init() puts the user's geometry (if any),
and where the device model gets it from.

Nobody complained, because the default physical geometry is the same
as vvfat's logical geometry:

    opts        LCHS        def. PCHS
                1024,16,63  same
    :32:        1024,16,63  same
    :16:        1024,16,63  same
    :12:          64,16,63  same

Except when you specify :floppy:

    opts        LCHS        def. PCHS
       :floppy:   80, 2,36  5,16,63
    :32:floppy:   80, 2,36  5,16,63
    :16:floppy:   80, 2,36  5,16,63
    :12:floppy:   80, 2,18  2,16,63

Silly thing to do for use with a hard disk.

However, the "raw" format can be suppressed by adding an
redundant-looking "format=vvfat" to "file=fat:FOO".  Then, vvfat's
hint clobbers the user's geometry, i.e. -drive options cyls, heads,
secs get silently ignored.  Don't do that.

No change without format=vvfat.  With it, the user's hard disk
geometry (-drive options cyls, heads, secs) is now obeyed, and the
default hard disk geometry with :floppy: now matches the one without
format=vvfat.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-17 16:48:30 +02:00
Markus Armbruster f91cbefe2d vvfat: Fix partition table
Unless parameter ":floppy:" is given, vvfat creates a virtual image
with DOS MBR defining a single partition which holds the FAT file
system.  The size of the virtual image depends on the width of the
FAT: 32 MiB (CHS 64, 16, 63) for 12 bit FAT, 504 MiB (CHS 1024, 16,
63) for 16 and 32 bit FAT, leaving (64*16-1)*63 = 64449 and
(1024*16-1)*64 = 1032129 sectors for the partition.

However, it screws up the end of the partition in the MBR:

    FAT width param.  start CHS  end CHS     start LBA  size
        :32:          0,1,1      1023,14,63       63    1032065
        :16:          0,1,1      1023,14,55       63    1032057
        :12:          0,1,1        63,14,55       63      64377

The actual FAT file system nevertheless assumes the partition has
1032129 or 64449 sectors.  Oops.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-17 16:48:30 +02:00
Christoph Hellwig 19db9b9042 sheepdog: do not blindly memset all read buffers
Only buffers that map to unallocated blocks need to be zeroed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-17 16:48:29 +02:00
MORITA Kazutaka cddd4ac7a2 sheepdog: always use coroutine-based network functions
This reduces some code duplication.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-17 16:48:29 +02:00
Anthony Liguori 23797df3d9 Merge remote-tracking branch 'mjt/mjt-iov2' into staging
* mjt/mjt-iov2:
  rewrite iov_send_recv() and move it to iov.c
  cleanup qemu_co_sendv(), qemu_co_recvv() and friends
  export iov_send_recv() and use it in iov_send() and iov_recv()
  rename qemu_sendv to iov_send, change proto and move declarations to iov.h
  change qemu_iovec_to_buf() to match other to,from_buf functions
  consolidate qemu_iovec_copy() and qemu_iovec_concat() and make them consistent
  allow qemu_iovec_from_buffer() to specify offset from which to start copying
  consolidate qemu_iovec_memset{,_skip}() into single function and use existing iov_memset()
  rewrite iov_* functions
  change iov_* function prototypes to be more appropriate
  virtio-serial-bus: use correct lengths in control_out() message

Conflicts:
	tests/Makefile

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-07-09 12:35:06 -05:00
Anthony Liguori 715cc00ce1 Merge remote-tracking branch 'kwolf/for-anthony' into staging
* kwolf/for-anthony: (24 commits)
  block: Factor bdrv_read_unthrottled() out of guess_disk_lchs()
  qtest: Tidy up temporary files properly
  fdc: Drop broken code for user-defined floppy geometry
  fdc_test: introduce test_sense_interrupt
  fdc_test: update media_change test
  fdc: fix interrupt handling
  fdc: rewrite seek and DSKCHG bit handling
  block: introduce bdrv_swap, implement bdrv_append on top of it
  block: copy over job and dirty bitmap fields in bdrv_append
  raw: hook into blkdebug
  blkdebug: optionally tie errors to a specific sector
  blkdebug: store list of active rules
  blkdebug: pass getlength to underlying file
  blkdebug: tiny cleanup
  blkdebug: remove sync i/o events
  sheepdog: traverse pending_list from the first for each time
  sheepdog: split outstanding list into inflight and pending
  sheepdog: make sure we don't free aiocb before sending all requests
  sheepdog: use coroutine based socket functions in coroutine context
  sheepdog: restart I/O when socket becomes ready in do_co_req()
  ...
2012-07-09 10:29:40 -05:00
Paolo Bonzini 5c171afa4c raw: hook into blkdebug
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:02 +02:00
Paolo Bonzini e4780db429 blkdebug: optionally tie errors to a specific sector
This makes blkdebug scripts more powerful, and independent of the
exact sequence of operations performed by streaming.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:02 +02:00
Paolo Bonzini 571cd43e57 blkdebug: store list of active rules
This prepares for the next patch, where some active rules may actually
not trigger depending on input to readv/writev.  Store the active rules
in a SIMPLEQ (so that it can be emptied easily with QSIMPLEQ_INIT), and
fetch the errno/once/immediately arguments from there.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:02 +02:00
Paolo Bonzini e130225587 blkdebug: pass getlength to underlying file
This is required when using blkdebug with raw format.  Unlike qcow2/QED,
raw asks blkdebug for the length of the file, it doesn't get it from
a header.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:02 +02:00
Paolo Bonzini 368e8dd10a blkdebug: tiny cleanup
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:02 +02:00
Paolo Bonzini 820100fd15 blkdebug: remove sync i/o events
These are unused, except (by mistake more or less) in QED.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:02 +02:00
MORITA Kazutaka 7dc1cde05b sheepdog: traverse pending_list from the first for each time
The pending list can be modified in other coroutine context
sd_co_rw_vector, so we need to traverse the list from the first again
after we send the pending request.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:02 +02:00
MORITA Kazutaka c292ee6a67 sheepdog: split outstanding list into inflight and pending
outstanding_list_head is used for both pending and inflight requests.
This patch splits it and improves readability.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:02 +02:00
MORITA Kazutaka 1d732d7d7c sheepdog: make sure we don't free aiocb before sending all requests
This patch increments the pending counter before sending requests, and
make sures that aiocb is not freed while sending them.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:01 +02:00
MORITA Kazutaka b97564f4c5 sheepdog: use coroutine based socket functions in coroutine context
This removes blocking network I/Os in coroutine context.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:01 +02:00
MORITA Kazutaka 2dfcca3b68 sheepdog: restart I/O when socket becomes ready in do_co_req()
Currently, no one reenters the yielded coroutine.  This fixes it.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:01 +02:00
MORITA Kazutaka 1b6ac9985a sheepdog: fix dprintf format strings
This fixes warnings about dprintf format in debug mode.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:01 +02:00
Stefan Hajnoczi 206e6d8551 qcow2: preserve free_byte_offset when qcow2_alloc_bytes() fails
When qcow2_alloc_clusters() error handling code was introduced in commit
5d757b563d, the value of free_byte_offset
was clobbered in the error case.  This patch keeps free_byte_offset at 0
so we will try to allocate clusters again next time this function is
called.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:01 +02:00
Stefan Hajnoczi b35278f754 qcow2: fix #ifdef'd qcow2_check_refcounts() callers
The DEBUG_ALLOC qcow2.h macro enables additional consistency checks
throughout the code.  This makes it easier to spot corruptions that are
introduced during development.  Since consistency check is an expensive
operation the DEBUG_ALLOC macro is used to compile checks out in normal
builds and qcow2_check_refcounts() calls missed the addition of a new
function argument.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-07-09 15:53:01 +02:00
Ronnie Sahlberg 622695a458 ISCSI: force use of sg for SMC and SSC devices
If the device we open is a SMC or SSC device, then force the use of sg. We
dont have any medium changer or tape emulation so only passthrough via
real sg or scsi-generic via iscsi would work anyway.

Forcing sg also makes qemu skip trying to read from the device to guess
the image format by reading from the device (find_image_format()).
SMC devices do not implement READ6/10/12/16 so it is not possible to
read from them (SSC have different CDBs).

With this patch I can successfully manage a SMC device wiht iscsi in
passthrough mode.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
[Added TYPE_TAPE handling - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-07-02 10:18:41 +02:00
Ronnie Sahlberg 983924532f ISCSI: Add SCSI passthrough via scsi-generic to libiscsi
Update iscsi to allow passthrough of SG_IO scsi commands when the iscsi
device is forced to be scsi-generic.

Implement both bdrv_ioctl() and bdrv_aio_ioctl() in the iscsi backend,
emulate the SG_IO ioctl and pass the SCSI commands across to the
iscsi target.

This allows end-to-end passthrough of SCSI all the way from the guest,
to qemu, via scsi-generic, then libiscsi all the way to the iscsi target.

To activate this you need to specify that the iscsi lun should be treated
as a scsi-generic device.

Example:
    -device lsi -device scsi-generic,drive=MyISCSI \
    -drive file=iscsi://10.1.1.125/iqn.ronnie.test/1,if=none,id=MyISCSI

Note, you can currently not boot a qemu guest from a scsi device.

Note,
This only works when the host is linux, since the emulation relies on
definitions of SG_IO from the scsi-generic implementation in the
linux kernel.
It should be fairly easy to re-implement some structures similar enough
for non-linux hosts to do the same style of passthrough via a fake
scsi generic layer and libiscsi if need be.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-07-02 10:18:41 +02:00
Kevin Wolf 94282e7146 raw-posix: Fix build without is_allocated support
Move the declaration of s into the #ifdef sections that actually make
use of it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2012-06-24 01:04:45 +02:00
Stefan Hajnoczi af7b708db2 qcow2: fix autoclear image header update
The autoclear feature bits can be used for qcow2 file format features
that are safe to "drop" by old programs that do not understand the
feature.  Upon opening the image file unknown autoclear feature bits are
cleared and the image file header is rewritten, but this was happening
too early in the code when critical header fields were not yet loaded.

Process autoclear feature bits after all necessary header information
has been loaded.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15 14:03:43 +02:00
Kevin Wolf b7ab0fea37 qcow2: Fix avail_sectors in cluster allocation code
avail_sectors should really be the number of sectors from the start of
the allocation, not from the start of the write request.

We're lucky enough that this mistake didn't cause any real bug.
avail_sectors is only used in the intialiser of QCowL2Meta:

  .nb_available   = MIN(requested_sectors, avail_sectors),

m->nb_available in turn is only used for COW at the end of the
allocation. A COW occurs only if the request wasn't cluster aligned,
which in turn would imply that requested_sectors was less than
avail_sectors (both in the original and in the fixed version). In this
case avail_sectors is ignored and therefore the mistake doesn't cause
any misbehaviour.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15 14:03:43 +02:00
Kevin Wolf cdba7fee1d qcow2: Simplify calculation for COW area at the end
copy_sectors() always uses the sum (cluster_offset + n_start) or
(start_sect + n_start), so if some value is added to both cluster_offset
and start_sect, and subtracted from n_start, it's cancelled out anyway.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15 14:03:43 +02:00
Paolo Bonzini 6af4e9ead4 qcow2: always operate caches in writeback mode
Writethrough does not need special-casing anymore in the qcow2 caches.
The block layer adds flushes after every guest-initiated data write,
and these will also flush the qcow2 caches to the OS.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15 14:03:43 +02:00