This is the next step for decoupling block accounting functions from
BlockDriverState.
In a future commit the BlockAcctStats structure will be moved from
BlockDriverState to the device models structures.

Note that bdrv_get_stats was introduced so device models can retrieve the
BlockAcctStats structure of a BlockDriverState without being aware of it's
layout.
This function should go away when BlockAcctStats will be embedded in the device
models structures.

CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Keith Busch <keith.busch@intel.com>
CC: Anthony Liguori <aliguori@amazon.com>
CC: "Michael S. Tsirkin" <mst@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Peter Maydell <peter.maydell@linaro.org>
CC: Michael Tokarev <mjt@tls.msk.ru>
CC: John Snow <jsnow@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Alexander Graf <agraf@suse.de>
CC: Max Reitz <mreitz@redhat.com>
Signed-off-by: NBenoît Canet <benoit.canet@nodalink.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The middle term goal is to move the BlockAcctStats structure in the device models.
(Capturing I/O accounting statistics in the device models is good for billing)
This patch make a small step in this direction by removing a reference to BDRV.

CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Keith Busch <keith.busch@intel.com>
CC: Anthony Liguori <aliguori@amazon.com>
CC: "Michael S. Tsirkin" <mst@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: John Snow <jsnow@redhat.com>
CC: Richard Henderson <rth@twiddle.net>
CC: Markus Armbruster <armbru@redhat.com>
CC: Alexander Graf <agraf@suse.de>i
Signed-off-by: NBenoît Canet <benoit.canet@nodalink.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The Error object was leaked after failed bdrv_new(). While there,
streamline control flow a bit.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Implement discard support for xen_disk. It makes use of the existing
discard code in qemu.

The discard support is enabled unconditionally. The tool stack may
provide a property "discard-enable" in the backend node to optionally
disable discard support.  This is helpful in case the backing file was
intentionally created non-sparse to avoid fragmentation.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

This patch adds an errp parameter to bdrv_new() and updates all its
callers. The next patches will make use of this in order to check for
duplicate IDs. Most of the callers know that their ID is fine, so they
can simply assert that there is no error.

Behaviour doesn't change with this patch yet as bdrv_new() doesn't
actually assign errors to errp.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Allow bdrv_open() to handle references to existing block devices just as
bdrv_file_open() is already capable of.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Make bdrv_open() take a pointer to a BDS pointer, similarly to
bdrv_file_open(). If a pointer to a NULL pointer is given, bdrv_open()
will create a new BDS with an empty name; if the BDS pointer is not
NULL, that existing BDS will be reused (in the same way as bdrv_open()
already did).
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

bdrv_acct_done was called unconditional. But in case the ioreq has no
segments there is no matching bdrv_acct_start call. This could lead to
bogus accounting values.

Found by code inspection.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

IF_NONE allows read-only, which makes forbidding it in this place
for other types pretty much pointless.

Instead, make sure that all devices for which the check would have
errored out check in their init function that they don't get a read-only
BlockDriverState. This catches even cases where IF_NONE and -device is
used.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Commit 4472beae modified the semantics of ioreq_{un,}map so that they are
idempotent if called when they're not needed (ie., twice in a row). However,
it neglected to handle the case where batch mapping is not being used (the
default), and one of the grants fails to map. In this case, ioreq_unmap will
be called to unwind and unmap any mappings already performed, but ioreq_unmap
simply returns due to the aforementioned change (the ioreq has not already
been marked as mapped).

The frontend user can therefore force xen_disk to leak grant mappings, a
per-domain limited resource.

Fix by marking the ioreq as mapped before calling ioreq_unmap in this
situation.
Signed-off-by: NMatthew Daley <mattjd@gmail.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Add an Error ** parameter to bdrv_open, bdrv_file_open and associated
functions to allow more specific error messages.
Signed-off-by: NMax Reitz <mreitz@redhat.com>

We call bdrv_attach_dev when initializing whether or not bs is created
locally, so call bdrv_detach_dev and let the refcnt handle the
lifecycle.
Signed-off-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Manage BlockDriverState lifecycle with refcnt, so bdrv_delete() is no
longer public and should be called by bdrv_unref() if refcnt is
decreased to 0.

This is an identical change because effectively, there's no multiple
reference of BDS now: no caller of bdrv_ref() yet, only bdrv_new() sets
bs->refcnt to 1, so all bdrv_unref() now actually delete the BDS.
Signed-off-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Support backend option "direct-io-safe".  This is documented as
follows in the Xen backend specification:

 * direct-io-safe
 *      Values:         0/1 (boolean)
 *      Default Value:  0
 *
 *      The underlying storage is not affected by the direct IO memory
 *      lifetime bug.  See:
 *        http://lists.xen.org/archives/html/xen-devel/2012-12/msg01154.html
 *
 *      Therefore this option gives the backend permission to use
 *      O_DIRECT, notwithstanding that bug.
 *
 *      That is, if this option is enabled, use of O_DIRECT is safe,
 *      in circumstances where we would normally have avoided it as a
 *      workaround for that bug.  This option is not relevant for all
 *      backends, and even not necessarily supported for those for
 *      which it is relevant.  A backend which knows that it is not
 *      affected by the bug can ignore this option.
 *
 *      This option doesn't require a backend to use O_DIRECT, so it
 *      should not be used to try to control the caching behaviour.

Also, BDRV_O_NATIVE_AIO is ignored if BDRV_O_NOCACHE, so clarify the
default flags passed to the qemu block layer.

The original proposal for a "cache" backend option has been dropped
because it was believed too wide, especially considering that at the
moment the backend doesn't have a way to tell the toolstack that it is
capable of supporting it.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NIan Jackson <Ian.Jackson@eu.citrix.com>

We may want to include a driver in the whitelist for read only tasks
such as diagnosing or exporting guest data (with libguestfs as a good
example). This patch introduces a readonly whitelist option, and for
backward compatibility, the old configure option --block-drv-whitelist
is now an alias to rw whitelist.

Drivers in readonly list is only permitted to open file readonly, and
returns -ENOTSUP for RW opening.

E.g. To include vmdk readonly, and others read+write:
    ./configure --target-list=x86_64-softmmu \
                --block-drv-rw-whitelist=qcow2,raw,file,qed \
                --block-drv-ro-whitelist=vmdk
Signed-off-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Many headers are used only in a single directory.  These can be
kept in hw/.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This patch tackles all files that are compiled once, moving
them to subdirectories of hw/.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Many of these should be cleaned up with proper qdev-/QOM-ification.
Right now there are many catch-all headers in include/hw/ARCH depending
on cpu.h, and this makes it necessary to compile these files per-target.
However, fixing this does not belong in these patches.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The current xen backend driver implementation uses int64_t variables
to store the size of the corresponding backend disk/file. It also uses
an int64_t variable to store the block size of that image. When writing
the number of sectors (file_size/block_size) to xenstore, however, it
passes these values as 32 bit signed integers. This will cause an
overflow for any disk of 1 TiB or more.

This patch changes the xen backend driver to use a 64 bit integer write
xenstore function.
Signed-off-by: NFelipe Franciosi <felipe@paradoxo.org>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Due to what is almost certainly a kernel bug, writes with O_DIRECT may
continue to reference the page after the write has been marked as
completed, particularly in the case of TCP retransmit. In other
scenarios, this "merely" risks data corruption on the write, but with
Xen pages from domU are only transiently mapped into dom0's memory,
resulting in kernel panics when they are subsequently accessed.

This brings PV devices in line with emulated devices.  Removing
O_DIRECT is safe as barrier operations are now correctly passed
through.

See:
   http://lists.xen.org/archives/html/xen-devel/2012-12/msg01154.html
for more details.
Signed-off-by: NAlex Bligh <alex@alex.org.uk>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

This commit delays the point at which bdrv_new (and hence blk_open
on the underlying device) is called from blk_init to blk_connect.
This ensures that in an inbound live migrate, the block device is
not opened until it has been closed at the other end. This is in
preparation for supporting devices with open/close consistency
without using O_DIRECT. This commit does NOT itself change O_DIRECT
semantics.
Signed-off-by: NAlex Bligh <alex@alex.org.uk>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

It doesn't do anything yet except storing the options QDict in the
BlockDriverState.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Done with this script:

cd hw
for i in `find . -name '*.h' | sed 's/^..//'`; do
  echo '\,^#.*include.*["<]'$i'[">], s,'$i',hw/&,'
done | sed -i -f - `find . -type f`

This is so that paths remain valid as files are moved.

Instead, files in hw/dataplane are referenced with the relative path.
We know they are not going to move to include/, and they are the only
include files that are in subdirectories _and_ move.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

This protocol extension reuses the same set of grant pages for all
transactions between the front/back drivers, avoiding expensive tlb
flushes, grant table lock contention and switches between userspace
and kernel space. The full description of the protocol can be found in
the public blkif.h header.

http://xenbits.xen.org/gitweb/?p=xen.git;a=blob_plain;f=xen/include/public/io/blkif.h

Speed improvement with 15 guests performing I/O is ~450%.
Signed-off-by: NRoger Pau Monné <roger.pau@citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

On ioreq_release the full ioreq was memset to 0, loosing all the data
and memory allocations inside the QEMUIOVector, which leads to a
memory leak. Create a new function to specifically reset ioreq.
Reported-by: NMaik Wessler <maik.wessler@yahoo.com>
Signed-off-by: NRoger Pau Monné <roger.pau@citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Touching char/char.h basically causes the whole of QEMU to
be rebuilt.  Avoid this, it is usually unnecessary.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Because xs.h will be remove in future release of Xen, this patch removes the
extra includes of this headers.

Also, it removes the extra includes of xenctrl.h and xen/io/xenbus.h as there
already are in xen_common.h.
Signed-off-by: NAnthony PERARD <anthony.perard@citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

First offender is xen_config_dev_blk()'s use of disk->bdrv->filename.
Get the filename from disk->opts instead.  Same result, except for
snapshots: there, we now get the filename specified by the user
instead of the name of the temporary image created by bdrv_open().
Should be an improvement.

Second offender is blk_init()'s use of blkdev->bs->drv->format_name.
Simply use the appropriate interface to get the format name.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Legacy (non-pvops) gntdev drivers may require this to be done when the
number of grants intended to be used simultaneously exceeds a certain
driver specific default limit.
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

While for the "normal" case (called from blk_send_response_all())
decrementing requests_finished is correct, doing so in the parse error
case is wrong; requests_inflight needs to be decremented instead.
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>

Use bdrv_aio_flush instead of bdrv_flush.

Make sure to call bdrv_aio_writev/readv after the presync bdrv_aio_flush is fully
completed and make sure to call the postsync bdrv_aio_flush after
bdrv_aio_writev/readv is fully completed.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

This patch removes a dead option.

The same can be achieved removing BDRV_O_NOCACHE and BDRV_O_CACHE_WB
from the flags passed to bdrv_open.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

We need to detach the blkdev from the BlockDriverState before calling
bdrv_delete.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

If ioreq->postsync call bdrv_flush when the AIO operation is actually
completed.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

All files under GPLv2 will get GPLv2+ changes starting tomorrow.
event_notifier.c and exec-obsolete.h were only ever touched by Red Hat
employees and can be relicensed now.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>