Commit Graph

1006 Commits

Author SHA1 Message Date
Alberto Garcia d5a8ee60a0 qmp: fill in the image field in BlockDeviceInfo
The image field in BlockDeviceInfo is supposed to contain an ImageInfo
object. However that is being filled in by bdrv_query_info(), not by
bdrv_block_device_info(), which is where BlockDeviceInfo is actually
created.

Anyone calling bdrv_block_device_info() directly will get a null image
field. As a consequence of this, the HMP command 'info block -n -v'
crashes QEMU.

This patch moves the code that fills in that field from
bdrv_query_info() to bdrv_block_device_info().

Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 1429271563-3765-1-git-send-email-berto@igalia.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28 15:36:09 +02:00
Alberto Garcia 81e5f78a9f block: use bdrv_get_device_or_node_name() in error messages
There are several error messages that identify a BlockDriverState by
its device name. However those errors can be produced in nodes that
don't have a device name associated.

In those cases we should use bdrv_get_device_or_node_name() to fall
back to the node name and produce a more meaningful message. The
messages are also updated to use the more generic term 'node' instead
of 'device'.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 9823a1f0514fdb0692e92868661c38a9e00a12d6.1428485266.git.berto@igalia.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28 15:36:09 +02:00
Alberto Garcia 9b2aa84f87 block: add bdrv_get_device_or_node_name()
This function gets the device name associated with a BlockDriverState,
or its node name if the device name is empty.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 4fa30aa8d61d9052ce266fd5429a59a14e941255.1428485266.git.berto@igalia.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28 15:36:09 +02:00
Paolo Bonzini 0b5a24454f block: avoid unnecessary bottom halves
bdrv_aio_* APIs can use coroutines to achieve asynchronicity.  However,
the coroutine may terminate without having yielded back to the caller
(for example because of something that invokes a nested event loop,
or because the coroutine is doing nothing at all).  In this case,
the bdrv_aio_* API must delay the completion to the next iteration
of the main loop, because bdrv_aio_* will never invoke the callback
before returning.

This can be done with a bottom half, and indeed bdrv_aio_* is always
using one for simplicity.  It is possible to gain some performance
(~3%) by avoiding this in the common case.  A new field in the
BlockAIOCBCoroutine struct is set to true until the first time the
corotine has yielded to its creator, and completion goes through a
new function bdrv_co_complete.  If the flag is false, bdrv_co_complete
invokes the callback immediately.  If it is true, the caller will
notice that the coroutine has completed and schedule the bottom
half itself.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1427524638-28157-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28 15:36:09 +02:00
Fam Zheng 69da3b0b47 block: Pause block jobs in bdrv_drain_all
This is necessary to suppress more IO requests from being generated from
block job coroutines.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 1428069921-2957-3-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28 15:36:09 +02:00
Fam Zheng de50a20a4c block: Switch to host monotonic clock for IO throttling
Currently, throttle timers won't make any progress when VCPU is not
running, which would stall the request queue in utils, qtest, vm
suspending, and live migration, without special handling.

Block jobs are confusingly inconsistent between with and without
throttling: if user sets a bps limit, stops the vm, then start a block
job, the block job will not make any progress; in contrary, if user
unsets the bps limit, or if it's not set, the block job will run
normally.

After this patch, with the host clock, even if the VCPUs are stopped,
the throttle queues will be processed.

This patch also enables potential to add throttle to bdrv_drain_all.
Currently all requests are drained immediately. In other words whenever
it is called, IO throttling goes ineffective (examples: system reset,
migration and many block job operations.). This is a loophole that guest
could exploit. If we use the host clock, we can later just trust the
nested poll. This could be done on top.

Note that for qemu-iotests case 093, which uses qtest, we still keep vm
clock so the script can control the clock stepping in order to be
deterministic.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1427268446-6426-1-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28 15:36:08 +02:00
Stefan Hajnoczi 786a4ea82e Convert (ffs(val) - 1) to ctz32(val)
This commit was generated mechanically by coccinelle from the following
semantic patch:

@@
expression val;
@@
- (ffs(val) - 1)
+ ctz32(val)

The call sites have been audited to ensure the ffs(0) - 1 == -1 case
never occurs (due to input validation, asserts, etc).  Therefore we
don't need to worry about the fact that ctz32(0) == 32.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1427124571-28598-5-git-send-email-stefanha@redhat.com
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28 15:36:08 +02:00
Fam Zheng fc3959e466 block: Fix unaligned zero write
If the zero write is not aligned, bdrv_co_do_pwritev will segfault
because of accessing to the NULL qiov passed in by bdrv_co_write_zeroes.
Fix this by allocating a local qiov in bdrv_co_do_pwritev if the request
is not aligned. (In this case the padding iovs are necessary anyway, so
it doesn't hurt.)

Also add a check at the end of bdrv_co_do_pwritev to clear the zero flag
if padding is involved.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1427160230-4489-2-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-03-27 10:01:12 +00:00
Fam Zheng d51a2427f6 block: Drop bdrv_find
All callers are converted, so drop it.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1425296209-1476-5-git-send-email-famz@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2015-03-16 12:10:30 -04:00
Markus Armbruster a1f688f415 block: Deprecate QCOW/QCOW2 encryption
We've steered users away from QCOW/QCOW2 encryption for a while,
because it's a flawed design (commit 136cd19 Describe flaws in
qcow/qcow2 encryption in the docs).

In addition to flawed crypto, we have comically bad usability, and
plain old bugs.  Let me show you.

= Example images =

I'm going to use a raw image as backing file, and two QCOW2 images,
one encrypted, and one not:

    $ qemu-img create -f raw backing.img 4m
    Formatting 'backing.img', fmt=raw size=4194304
    $ qemu-img create -f qcow2 -o encryption,backing_file=backing.img,backing_fmt=raw geheim.qcow2 4m
    Formatting 'geheim.qcow2', fmt=qcow2 size=4194304 backing_file='backing.img' backing_fmt='raw' encryption=on cluster_size=65536 lazy_refcounts=off
    $ qemu-img create -f qcow2 -o backing_file=backing.img,backing_fmt=raw normal.qcow2 4m
    Formatting 'normal.qcow2', fmt=qcow2 size=4194304 backing_file='backing.img' backing_fmt='raw' encryption=off cluster_size=65536 lazy_refcounts=off

= Usability issues =

== Confusing startup ==

When no image is encrypted, and you don't give -S, QEMU starts the
guest immediately:

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio normal.qcow2
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) info status
    VM status: running

But as soon as there's an encrypted image in play, the guest is *not*
started, with no notification whatsoever:

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio geheim.qcow2
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) info status
    VM status: paused (prelaunch)

If the user figured out that he needs to type "cont" to enter his
keys, the confusion enters the next level: "cont" asks for at most
*one* key.  If more are needed, it then silently does nothing.  The
user has to type "cont" once per encrypted image:

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio -drive if=none,file=geheim.qcow2 -drive if=none,file=geheim.qcow2
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) info status
    VM status: paused (prelaunch)
    (qemu) c
    none0 (geheim.qcow2) is encrypted.
    Password: ******
    (qemu) info status
    VM status: paused (prelaunch)
    (qemu) c
    none1 (geheim.qcow2) is encrypted.
    Password: ******
    (qemu) info status
    VM status: running

== Incorrect passwords not caught ==

All existing encryption schemes give you the GIGO treatment: garbage
password in, garbage data out.  Guests usually refuse to mount
garbage, but other usage is prone to data loss.

== Need to stop the guest to add an encrypted image ==

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) info status
    VM status: running
    (qemu) drive_add "" if=none,file=geheim.qcow2
    Guest must be stopped for opening of encrypted image
    (qemu) stop
    (qemu) drive_add "" if=none,file=geheim.qcow2
    OK

Commit c3adb58 added this restriction.  Before, we could expose images
lacking an encryption key to guests, with potentially catastrophic
results.  See also "Use without key is not always caught".

= Bugs =

== Use without key is not always caught ==

Encrypted images can be in an intermediate state "opened, but no key".
The weird startup behavior and the need to stop the guest are there to
ensure the guest isn't exposed to that state.  But other things still
are!

* drive_backup

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio geheim.qcow2
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) drive_backup -f ide0-hd0 out.img raw
    Formatting 'out.img', fmt=raw size=4194304

  I guess this writes encrypted data to raw image out.img.  Good luck
  with figuring out how to decrypt that again.

* commit

    $ qemu-system-x86_64 -nodefaults -display none -monitor stdio geheim.qcow2
    QEMU 2.2.50 monitor - type 'help' for more information
    (qemu) commit ide0-hd0

  I guess this writes encrypted data into the unencrypted raw backing
  image, effectively destroying it.

== QMP device_add of usb-storage fails when it shouldn't ==

When the image is encrypted, device_add creates the device, defers
actually attaching it to when the key becomes available, then fails.
This is wrong.  device_add must either create the device and succeed,
or do nothing and fail.

    $ qemu-system-x86_64 -nodefaults -display none -usb -qmp stdio -drive if=none,id=foo,file=geheim.qcow2
    {"QMP": {"version": {"qemu": {"micro": 50, "minor": 2, "major": 2}, "package": ""}, "capabilities": []}}
    { "execute": "qmp_capabilities" }
    {"return": {}}
    { "execute": "device_add", "arguments": { "driver": "usb-storage", "id": "bar", "drive": "foo" } }
    {"error": {"class": "DeviceEncrypted", "desc": "'foo' (geheim.qcow2) is encrypted"}}
    {"execute":"device_del","arguments": { "id": "bar" } }
    {"timestamp": {"seconds": 1426003440, "microseconds": 237181}, "event": "DEVICE_DELETED", "data": {"path": "/machine/peripheral/bar/bar.0/legacy[0]"}}
    {"timestamp": {"seconds": 1426003440, "microseconds": 238231}, "event": "DEVICE_DELETED", "data": {"device": "bar", "path": "/machine/peripheral/bar"}}
    {"return": {}}

This stuff is worse than useless, it's a trap for users.

If people become sufficiently interested in encrypted images to
contribute a cryptographically sane implementation for QCOW2 (or
whatever other format), then rewriting the necessary support around it
from scratch will likely be easier and yield better results than
fixing up the existing mess.

Let's deprecate the mess now, drop it after a grace period, and move
on.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-03-16 17:07:25 +01:00
Ekaterina Tumanova 892b7de832 block: add bdrv functions for geometry and blocksize
Add driver functions for geometry and blocksize detection

Signed-off-by: Ekaterina Tumanova <tumanova@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1424087278-49393-2-git-send-email-tumanova@linux.vnet.ibm.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-03-10 14:02:21 +01:00
Markus Armbruster dc523cd348 qemu-img: Suppress unhelpful extra errors in convert, amend
img_convert() and img_amend() use qemu_opts_do_parse(), which reports
errors with qerror_report_err().  Its error messages aren't helpful
here, the caller reports one that actually makes sense.  Reproducer:

    $ qemu-img convert -o backing_format=raw in.img out.img
    qemu-img: Invalid parameter 'backing_format'
    qemu-img: Invalid options for file format 'raw'

To fix, propagate errors through qemu_opts_do_parse().  This lifts the
error reporting into callers.  Drop it from img_convert() and
img_amend(), keep it in qemu_chr_parse_compat(), bdrv_img_create().

Since I'm touching qemu_opts_do_parse() anyway, write a function
comment for it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-02-26 14:51:21 +01:00
Markus Armbruster f43e47dbf6 QemuOpts: Drop qemu_opt_set(), rename qemu_opt_set_err(), fix use
qemu_opt_set() is a wrapper around qemu_opt_set() that reports the
error with qerror_report_err().

Most of its users assume the function can't fail.  Make them use
qemu_opt_set_err() with &error_abort, so that should the assumption
ever break, it'll break noisily.

Just two users remain, in util/qemu-config.c.  Switch them to
qemu_opt_set_err() as well, then rename qemu_opt_set_err() to
qemu_opt_set().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-02-26 14:49:31 +01:00
Markus Armbruster 6be4194b92 block: Suppress unhelpful extra errors in bdrv_img_create()
bdrv_img_create() uses qemu_opt_set(), which reports errors with
qerror_report_err().  Its error messages aren't helpful here, the
caller reports one that actually makes sense.  I don't know how to
trigger the error conditions, though.

Switch to qemu_opt_set_err() to get rid of the unwanted messages.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-02-26 14:48:31 +01:00
Markus Armbruster 39101f2511 QemuOpts: Convert qemu_opt_set_number() to Error, fix its use
Return the Error object instead of reporting it with
qerror_report_err().

Change callers that assume the function can't fail to pass
&error_abort, so that should the assumption ever break, it'll break
noisily.

Turns out all callers outside its unit test assume that.  We could
drop the Error ** argument, but that would make the interface less
regular, so don't.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-02-26 14:47:32 +01:00
Max Reitz b9c649470b block: Keep bdrv_check*_request()'s return value
Do not throw away the value returned by bdrv_check_request() and
bdrv_check_byte_request().

Fix up some coding style issues in the proximity of the affected hunks.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1423162705-32065-17-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-02-16 15:07:19 +00:00
Max Reitz c0191e763b block: Remove "growable" from BDS
Now that request clamping is done in the BlockBackend, the "growable"
field can be removed from the BlockDriverState. All BDSs are now treated
as being "growable" (that is, they are allowed to grow; they are not
necessarily actually able to).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1423162705-32065-16-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-02-16 15:07:19 +00:00
Max Reitz b65a5e12a4 block: Add Error parameter to bdrv_find_protocol()
The argument given to bdrv_find_protocol() is just a file name, which
makes it difficult for the caller to reconstruct what protocol
bdrv_find_protocol() was hoping to find. This patch adds an Error
parameter to that function to solve this issue.

Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1423162705-32065-4-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-02-16 15:07:18 +00:00
Markus Armbruster b1ca639184 block: Eliminate silly QERR_ macros used for encryption keys
The QERR_ macros are leftovers from the days of "rich" error objects.
They're used with error_set() and qerror_report(), and expand into the
first *two* arguments.  This trickiness has become pointless.  Clean
up QERR_DEVICE_ENCRYPTED and QERR_DEVICE_NOT_ENCRYPTED.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1422524221-8566-5-git-send-email-armbru@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2015-02-06 11:46:32 -05:00
Markus Armbruster 4d2855a348 block: New bdrv_add_key(), convert monitor to use it
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1422524221-8566-4-git-send-email-armbru@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2015-02-06 11:46:32 -05:00
Peter Lieven 75af1f34cd block: introduce BDRV_REQUEST_MAX_SECTORS
we check and adjust request sizes at several places with
sometimes inconsistent checks or default values:
 INT_MAX
 INT_MAX >> BDRV_SECTOR_BITS
 UINT_MAX >> BDRV_SECTOR_BITS
 SIZE_MAX >> BDRV_SECTOR_BITS

This patches introdocues a macro for the maximal allowed sectors
per request and uses it at several places.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:22 +01:00
Peter Lieven f4564d53c6 block: add accounting for merged requests
Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Lieven 98764152ad block: change default for discard and write zeroes to INT_MAX
do not trim requests if the driver does not supply a limit
through BlockLimits. For write zeroes we still keep a limit
for the unsupported path to avoid allocating a big bounce buffer.

Suggested-by: Kevin Wolf <kwolf@redhat.com>
Suggested-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Jeff Cody a1a11d10ab block: remove unused variable in bdrv_commit
As Stefan pointed out, the variable 'filename' in bdrv_commit is unused,
despite being maintained in previous patches.

With this patch, get rid of the variable for good.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-01-23 18:17:06 +01:00
Fam Zheng bb00021de0 block: Split BLOCK_OP_TYPE_COMMIT to BLOCK_OP_TYPE_COMMIT_{SOURCE, TARGET}
Like BLOCK_OP_TYPE_BACKUP_SOURCE and BLOCK_OP_TYPE_BACKUP_TARGET,
block-commit involves two asymmetric devices.

This change is not user-visible (yet), because commit only works with
device names.

But once we enable backing reference in blockdev-add, or specifying
node-name in block-commit command, we don't want the user to start two
commit jobs on the same backing chain, which will corrupt things because
of the final bdrv_swap.

Before we have per category blockers, splitting this type is still
better.

[Resolved virtio-blk dataplane conflict by replacing
BLOCK_OP_TYPE_COMMIT with both BLOCK_OP_TYPE_COMMIT_{SOURCE, TARGET}.
They are safe since the block job runs in the same AioContext as the
dataplane IOThread.
--Stefan]

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-01-13 13:43:29 +00:00
Peter Lieven 095e4fa4b5 block: limited request size in write zeroes unsupported path
If bs->bl.max_write_zeroes is large and we end up in the unsupported
path we might allocate a lot of memory for the iovector and/or even
generate an oversized requests.

Fix this by limiting the request by the minimum of the reported
maximum transfer size or 16MB (32768 sectors).

Reported-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Message-id: 1420457389-16332-1-git-send-email-pl@kamp.de
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-01-13 13:43:29 +00:00
Vladimir Sementsov-Ogievskiy c4237dfa63 block: fix spoiling all dirty bitmaps by mirror and migration
Mirror and migration use dirty bitmaps for their purposes, and since
commit [block: per caller dirty bitmap] they use their own bitmaps, not
the global one. But they use old functions bdrv_set_dirty and
bdrv_reset_dirty, which change all dirty bitmaps.

Named dirty bitmaps series by Fam and Snow are affected: mirroring and
migration will spoil all (not related to this mirroring or migration)
named dirty bitmaps.

This patch fixes this by adding bdrv_set_dirty_bitmap and
bdrv_reset_dirty_bitmap, which change concrete bitmap. Also, to prevent
such mistakes in future, old functions bdrv_(set,reset)_dirty are made
static, for internal block usage.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@parallels.com>
CC: John Snow <jsnow@redhat.com>
CC: Fam Zheng <famz@redhat.com>
CC: Denis V. Lunev <den@openvz.org>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1417081246-3593-1-git-send-email-vsementsov@parallels.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2015-01-13 11:47:56 +00:00
Max Reitz 291680186f block: Relative backing file for image creation
Relative backing filenames are always relative to the backed image's
directory; the same applies to image creation. Therefore, if the backing
file has to be opened for determining its size (in case the size has not
been explicitly specified) its filename should be interpreted relative
to the new image's base directory and not relative to qemu's working
directory.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-01-13 11:47:56 +00:00
Max Reitz 9f07429e88 block: JSON filenames and relative backing files
When using a relative backing file name, qemu needs to know the
directory of the top image file. For JSON filenames, such a directory
cannot be easily determined (e.g. how do you determine the directory of
a qcow2 BDS directly on top of a quorum BDS?). Therefore, do not allow
relative filenames for the backing file of BDSs only having a JSON
filename.

Furthermore, BDS::exact_filename should be used whenever possible. If
BDS::filename is not equal to BDS::exact_filename, the former will
always be a JSON object.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-01-13 11:47:56 +00:00
Max Reitz 0a82855a1a block: Get full backing filename from string
Introduce bdrv_get_full_backing_filename_from_filename(), a function
which takes the name of the backed file and a potentially relative
backing filename to produce the full (absolute) backing filename.

Use this function from bdrv_get_full_backing_filename().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-01-13 11:47:56 +00:00
Paolo Bonzini e012b78cf5 block: do not allocate an iovec per read of a growable/zero_after_eof BDS
Most reads do not go past the end of the file, and they can use the
input QEMUIOVector instead of creating one.  This removes the
qemu_iovec_* functions from the profile.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-01-13 11:47:56 +00:00
Fam Zheng 43c5d8f800 block: Don't add trailing space in "Formating..." message
Change the message printing code to output a separator for each option
string before it instead of after, then we don't one more extra ' ' in
the end.

To update qemu-iotests output files, most of the times one would just
copy the *.out.bad to *.out. With this change we will not have the
space disliked by checkpatch.pl.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1418110684-19528-3-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-12-12 16:52:33 +00:00
Max Reitz 5c98415b2a vmdk: Fix error for JSON descriptor file names
If vmdk blindly tries to use path_combine() using bs->file->filename as
the base file name, this will result in a bad error message for JSON
file names when calling bdrv_open(). It is better to only try
bs->file->exact_filename; if that is empty, bs->file->filename will be
useless for path_combine() and an error should be emitted (containing
bs->file->filename because desc_file_path (which is
bs->file->exact_filename) is empty).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1417615043-26174-2-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-12-12 13:14:10 +00:00
Max Reitz c614972408 block: Check create_opts before image creation
If a driver supports image creation, it needs to set the .create_opts
field. We can use that to make sure .create_opts for both drivers
involved is not NULL in bdrv_img_create(), which is important so that
the create_opts pointer in that function is not NULL after the
qemu_opts_append() calls and when going into qemu_opts_create().

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10 10:31:20 +01:00
Max Reitz ef8104378c block: Omit bdrv_find_format for essential drivers
We can always assume raw, file and qcow2 being available; so do not use
bdrv_find_format() to locate their BlockDriver objects but statically
reference the respective objects.

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10 10:31:19 +01:00
Kevin Wolf c5f6e493bb block: Don't probe for unknown backing file format
If a qcow2 image specifies a backing file format that doesn't correspond
to any format driver that qemu knows, we shouldn't fall back to probing,
but simply error out.

Not looking up the backing file driver in bdrv_open_backing_file(), but
just filling in the "driver" option if it isn't there moves us closer to
the goal of having everything in QDict options and gets us the error
handling of bdrv_open(), which correctly refuses unknown drivers.

Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1416935562-7760-4-git-send-email-kwolf@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10 10:31:13 +01:00
Kevin Wolf 38f3ef574b raw: Prohibit dangerous writes for probed images
If the user neglects to specify the image format, QEMU probes the
image to guess it automatically, for convenience.

Relying on format probing is insecure for raw images (CVE-2008-2004).
If the guest writes a suitable header to the device, the next probe
will recognize a format chosen by the guest.  A malicious guest can
abuse this to gain access to host files, e.g. by crafting a QCOW2
header with backing file /etc/shadow.

Commit 1e72d3b (April 2008) provided -drive parameter format to let
users disable probing.  Commit f965509 (March 2009) extended QCOW2 to
optionally store the backing file format, to let users disable backing
file probing.  QED has had a flag to suppress probing since the
beginning (2010), set whenever a raw backing file is assigned.

All of these additions that allow to avoid format probing have to be
specified explicitly. The default still allows the attack.

In order to fix this, commit 79368c8 (July 2010) put probed raw images
in a restricted mode, in which they wouldn't be able to overwrite the
first few bytes of the image so that they would identify as a different
image. If a write to the first sector would write one of the signatures
of another driver, qemu would instead zero out the first four bytes.
This patch was later reverted in commit 8b33d9e (September 2010) because
it didn't get the handling of unaligned qiov members right.

Today's block layer that is based on coroutines and has qiov utility
functions makes it much easier to get this functionality right, so this
patch implements it.

The other differences of this patch to the old one are that it doesn't
silently write something different than the guest requested by zeroing
out some bytes (it fails the request instead) and that it doesn't
maintain a list of signatures in the raw driver (it calls the usual
probe function instead).

Note that this change doesn't introduce new breakage for false positive
cases where the guest legitimately writes data into the first sector
that matches the signatures of an image format (e.g. for nested virt):
These cases were broken before, only the failure mode changes from
corruption after the next restart (when the wrong format is probed) to
failing the problematic write request.

Also note that like in the original patch, the restrictions only apply
if the image format has been guessed by probing. Explicitly specifying a
format allows guests to write anything they like.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1416497234-29880-8-git-send-email-kwolf@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10 10:31:13 +01:00
Kevin Wolf 7cddd3728e block: Read only one sector for format probing
The only image format driver that even potentially accesses anything
after 512 bytes in its bdrv_probe() implementation is VMDK, which reads
a plain-text descriptor file. In practice, the field it's looking for
seems to come first and will be well within the first 512 bytes, too.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1416497234-29880-7-git-send-email-kwolf@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10 10:31:12 +01:00
Markus Armbruster c6684249fd block: Factor bdrv_probe_all() out of find_image_format()
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1416497234-29880-6-git-send-email-kwolf@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10 10:31:12 +01:00
Fam Zheng 20a9e77dfa block: Add bdrv_get_node_name
This returns the node name of a BDS. Remove the TODO comment and expect
the callers to be explicit.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10 10:25:29 +01:00
Fam Zheng 04df765ab4 block: Add bdrv_next_node
Similar to bdrv_next, this traverses through graph_bdrv_states. Will be
useful to enumerate all the named nodes.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10 10:25:29 +01:00
Fam Zheng f3a9cfddae block: Fix max nb_sectors in bdrv_make_zero
In bdrv_rw_co we report -EINVAL for nb_sectors > INT_MAX /
BDRV_SECTOR_SIZE, so a caller shouldn't exceed it.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1415603264-21497-1-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-11-14 09:20:35 +00:00
Peter Maydell 776346cd63 trivial patches for 2014-11-11
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Merge remote-tracking branch 'remotes/mjt/tags/pull-trivial-patches-2014-11-11' into staging

trivial patches for 2014-11-11

# gpg: Signature made Tue 11 Nov 2014 14:38:39 GMT using RSA key ID A4C3D7DB
# gpg: Good signature from "Michael Tokarev <mjt@tls.msk.ru>"
# gpg:                 aka "Michael Tokarev <mjt@corpit.ru>"
# gpg:                 aka "Michael Tokarev <mjt@debian.org>"

* remotes/mjt/tags/pull-trivial-patches-2014-11-11:
  block: Fix comment for bdrv_co_get_block_status
  sysbus: Correct SYSTEM_BUS(obj) defines
  target-i386: cpu: keeping function parameters alignment on new line
  xen-hvm: Remove redundant variable 'xstate'
  coroutine-sigaltstack: Change jmp_buf to sigjmp_buf
  pc-bios: petalogix-s3adsp1800.dtb: Use 'xlnx, xps-ethernetlite-2.00.a' instead of 'xlnx, xps-ethernetlite-2.00.b'
  gdbstub: Add a missing case of signal number translation in gdbstub
  numa: make 'info numa' take into account hotplugged memory
  slirp/smbd: modify/set several parameters in generated smbd.conf
  qemu-doc.texi: fix typos in x509 examples
  icc_bus: fix typo ICC_BRIGDE -> ICC_BRIDGE

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-11-11 14:50:10 +00:00
Fam Zheng 705be728c0 block: Fix comment for bdrv_co_get_block_status
It returns more information than binary, fix the comment.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-11-11 17:36:19 +03:00
Max Reitz e56934bece block: Propagate error in bdrv_img_create()
If the specified backing file could not be opened, do not generate a new
error message which contains the message which has been generated by
bdrv_open(), but just propagate the latter.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-11-06 12:45:47 +01:00
Stefan Hajnoczi 5a7e7a0bad block: let mirror blockjob run in BDS AioContext
The mirror block job must run in the BlockDriverState AioContext so that
it works with dataplane.

Acquire the AioContext in blockdev.c so starting the block job is safe.

Note that to_replace is treated separately from other BlockDriverStates
in that it does not need to be in the same AioContext.  Explicitly
acquire/release to_replace's AioContext when accessing it.

The completion code in block/mirror.c must perform BDS graph
manipulation and bdrv_reopen() from the main loop.  Use
block_job_defer_to_main_loop() to achieve that.

The bdrv_drain_all() call is not allowed outside the main loop since it
could lead to lock ordering problems.  Use bdrv_drain(bs) instead
because we have acquired the AioContext so nothing else can sneak in
I/O.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1413889440-32577-10-git-send-email-stefanha@redhat.com
2014-11-03 11:41:49 +00:00
Stefan Hajnoczi 5b98db0ad3 block: add bdrv_drain()
Now that op blockers are in use, we can ensure that no other sources are
generating I/O on a BlockDriverState.  Therefore it is possible to drain
requests for a single BDS.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1413889440-32577-7-git-send-email-stefanha@redhat.com
2014-11-03 11:41:49 +00:00
Max Reitz 7748543420 block: Add status callback to bdrv_amend_options()
Depending on the changed options and the image format,
bdrv_amend_options() may take a significant amount of time. In these
cases, a way to be informed about the operation's status is desirable.

Since the operation is rather complex and may fundamentally change the
image, implementing it as AIO or a coroutine does not seem feasible. On
the other hand, implementing it as a block job would be significantly
more difficult than a simple callback and would not add benefits other
than progress report to the amending operation, because it should not
actually be run as a block job at all.

A callback may not be very pretty, but it's very easy to implement and
perfectly fits its purpose here.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1414404776-4919-2-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-11-03 11:41:48 +00:00
Peter Maydell 573742a543 block.c: Fix type of IoOperationType variable in send_qmp_error_event()
The local variable 'ac' in send_qmp_error_event() is declared with the
wrong type, which causes clang to complain when it is initialized
and again when it is used:

block.c:3655:20: warning: implicit conversion from enumeration type 'enum IoOperationType' to different enumeration type 'BlockErrorAction' (aka 'enum BlockErrorAction') [-Wenum-conversion]
    ac = is_read ? IO_OPERATION_TYPE_READ : IO_OPERATION_TYPE_WRITE;
       ~           ^~~~~~~~~~~~~~~~~~~~~~
block.c:3655:45: warning: implicit conversion from enumeration type 'enum IoOperationType' to different enumeration type 'BlockErrorAction' (aka 'enum BlockErrorAction') [-Wenum-conversion]
    ac = is_read ? IO_OPERATION_TYPE_READ : IO_OPERATION_TYPE_WRITE;
       ~                                    ^~~~~~~~~~~~~~~~~~~~~~~
block.c:3656:62: warning: implicit conversion from enumeration type 'BlockErrorAction' (aka 'enum BlockErrorAction') to different enumeration type 'IoOperationType' (aka 'enum IoOperationType') [-Wenum-conversion]
    qapi_event_send_block_io_error(bdrv_get_device_name(bs), ac, action,
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                           ^~

Correct the type to IoOperationType, and rename the variable
to 'optype' to match its correct type.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Message-id: 1412969583-21045-1-git-send-email-peter.maydell@linaro.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-11-03 09:48:41 +00:00
Peter Lieven 6c5a42ac34 block: avoid creating oversized writes in multiwrite_merge
Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-11-03 09:48:41 +00:00
Peter Lieven 2647fab57d BlockLimits: introduce max_transfer_length
Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-11-03 09:48:41 +00:00
Max Reitz 59c9a95fd2 block: Respect underlying file's EOF
When falling through to the underlying file in
bdrv_co_get_block_status(), if it returns that the query offset is
beyond the file end (by setting *pnum to 0), return the range to be
zero and do not let the number of sectors for which information could be
obtained be overwritten.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-23 15:34:02 +02:00
Max Reitz 9ebd844805 block: Add qemu_{,try_}blockalign0()
These functions call their non-0-counterparts and then fill the
allocated buffer with 0 (if the allocation has been successful).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-23 15:34:01 +02:00
Markus Armbruster a7f53e26a6 block: Lift device model API into BlockBackend
Move device model attachment / detachment and the BlockDevOps device
model callbacks and their wrappers from BlockDriverState to
BlockBackend.

Wrapper calls in block.c change from

    bdrv_dev_FOO_cb(bs, ...)

to

    if (bs->blk) {
        bdrv_dev_FOO_cb(bs->blk, ...);
    }

No change, because both bdrv_dev_change_media_cb() and
bdrv_dev_resize_cb() do nothing when no device model is attached, and
a device model can be attached only when bs->blk.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20 14:03:50 +02:00
Markus Armbruster 097310b53e block: Rename BlockDriverCompletionFunc to BlockCompletionFunc
I'll use it with block backends shortly, and the name is going to fit
badly there.  It's a block layer thing anyway, not just a block driver
thing.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20 13:41:27 +02:00
Markus Armbruster 7c84b1b831 block: Rename BlockDriverAIOCB* to BlockAIOCB*
I'll use BlockDriverAIOCB with block backends shortly, and the name is
going to fit badly there.  It's a block layer thing anyway, not just a
block driver thing.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20 13:41:27 +02:00
Markus Armbruster 7f06d47eff block: Merge BlockBackend and BlockDriverState name spaces
BlockBackend's name space is separate only to keep the initial patches
simple.  Time to merge the two.

Retain bdrv_find() and bdrv_get_device_name() for now, to keep this
series manageable.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20 13:41:26 +02:00
Markus Armbruster bfb197e0d9 block: Eliminate BlockDriverState member device_name[]
device_name[] can become non-empty only in bdrv_new_root() and
bdrv_move_feature_fields().  The latter is used only to undo damage
done by bdrv_swap().  The former is called only by blk_new_with_bs().
Therefore, when a BlockDriverState's device_name[] is non-empty, then
it's been created with a BlockBackend, and vice versa.  Furthermore,
blk_new_with_bs() keeps the two names equal.

Therefore, device_name[] is redundant.  Eliminate it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20 13:41:26 +02:00
Markus Armbruster fea68bb6e9 block: Eliminate bdrv_iterate(), use bdrv_next()
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20 13:41:26 +02:00
Markus Armbruster 18e46a033d block: Connect BlockBackend and DriveInfo
Make the BlockBackend own the DriveInfo.  Change blockdev_init() to
return the BlockBackend instead of the DriveInfo.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20 13:41:26 +02:00
Markus Armbruster 7e7d56d9e0 block: Connect BlockBackend to BlockDriverState
Convenience function blk_new_with_bs() creates a BlockBackend with its
BlockDriverState.  Callers have to unref both.  The commit after next
will relieve them of the need to unref the BlockDriverState.

Complication: due to the silly way drive_del works, we need a way to
hide a BlockBackend, just like bdrv_make_anon().  To emphasize its
"special" status, give the function a suitably off-putting name:
blk_hide_on_behalf_of_do_drive_del().  Unfortunately, hiding turns the
BlockBackend's name into the empty string.  Can't avoid that without
breaking the blk->bs->device_name equals blk->name invariant.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20 13:41:26 +02:00
Markus Armbruster e4e9986b1c block: Split bdrv_new_root() off bdrv_new()
Creating an anonymous BDS can't fail.  Make that obvious.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20 13:41:26 +02:00
Alexey Kardashevskiy 7ea2d269cb block/migration: Disable cache invalidate for incoming migration
When migrated using libvirt with "--copy-storage-all", at the end of
migration there is race between NBD mirroring task trying to do flush
and migration completion, both end up invalidating cache. Since qcow2
driver does not handle this situation very well, random crashes happen.

This disables the BDRV_O_INCOMING flag for the block device being migrated
once the cache has been invalidated.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

--

fixed parens by hand
Signed-off-by: Juan Quintela <quintela@redhat.com>
2014-10-14 09:35:21 +02:00
Markus Armbruster f5bebbbb28 util: Emancipate id_wellformed() from QemuOpts
IDs have long spread beyond QemuOpts: not everything with an ID
necessarily goes through QemuOpts.  Commit 9aebf3b is about such a
case: block layer names are meant to be well-formed IDs, but some of
them don't go through QemuOpts, and thus weren't checked.  The commit
fixed that the straightforward way: rename the internal QemuOpts
helper id_wellformed() to qemu_opts_id_wellformed() and give it
external linkage.

Instead of using it directly in block.c, the commit adds wrapper
bdrv_is_valid_name(), probably to hide the connection to QemuOpts.

Go one logical step further: emancipate IDs from QemuOpts.  Rename the
function back to id_wellformed(), and put it in another file.  While
there, clean up its value to bool.  Peel off the bdrv_is_valid_name()
wrapper.

[Replaced stray return 0 with return false to match bool returns used
elsewhere in id_wellformed().
--Stefan]

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-10-03 10:30:33 +01:00
Kevin Wolf 9aebf3b892 block: Validate node-name
The device_name of a BlockDriverState is currently checked because it is
always used as a QemuOpts ID and qemu_opts_create() checks whether such
IDs are wellformed.

node-name is supposed to share the same namespace, but it isn't checked
currently. This patch adds explicit checks both for device_name and
node-name so that the same rules will still apply even if QemuOpts won't
be used any more at some point.

qemu-img used to use names with spaces in them, which isn't allowed any
more. Replace them with underscores.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-25 15:24:32 +02:00
Markus Armbruster d224469d87 block: Improve message for device name clashing with node name
Suggested-by: Benoit Canet <benoit.canet@nodalink.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-25 15:24:14 +02:00
Markus Armbruster 3ae59580a0 block: Keep DriveInfo alive until BlockDriverState dies
If the BDS's refcnt > 0, drive_del() destroys the DriveInfo, but not
the BDS.  This can happen in three places:

* Device model destruction during unplug: blockdev_auto_del()

* Xen IDE unplug: pci_piix3_xen_ide_unplug()

* drive_del command when no device model is attached: do_drive_del()

The other callers of drive_del are on error paths where refcnt == 1.

If the user somehow manages to plug in a device model using a BDS that
has gone through drive_del(), the legacy configuration passed in
DriveInfo doesn't reach the device model, and automatic deletion on
unplug doesn't work.  Worse, some device models such as scsi-disk
crash when DriveInfo doesn't exist.

This is theoretical; I didn't research an actual reproducer. The problem
was introduced when we replaced DriveInfo reference counting by BDS
reference counting in commit a94a3fa..fa510eb.

Fix by keeping DriveInfo alive until its BDS dies.

This affects qemu_drive_opts: now you can't reuse the same ID for new
drive options until the BDS dies.  Before, you could, but since the
code always attempts to create a BDS with the same ID next, the
enclosing operation "create a new drive" failed anyway.  Different
error path, same result.

Unfortunately, the fix involves use of blockdev.c stuff from block.c,
which is a layering violation.  Fortunately, my forthcoming
BlockBackend work will get rid of it again.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-25 15:24:14 +02:00
Fam Zheng 8007429a99 block: Rename qemu_aio_release -> qemu_aio_unref
Suggested-by: Benoît Canet <benoit.canet@irqsave.net>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22 11:39:17 +01:00
Fam Zheng ca5fd113b8 block: Drop AIOCBInfo.cancel
Now that all the implementations are converted to asynchronous version
and we can emulate synchronous cancellation with it. Let's drop the
unused member.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22 11:39:16 +01:00
Fam Zheng f600ac1902 block: Drop bdrv_em_aiocb_info.cancel
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22 11:39:00 +01:00
Fam Zheng 3acabd685e block: Drop bdrv_em_co_aiocb_info.cancel
Also drop the now unused ->done pointer.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22 11:38:59 +01:00
Fam Zheng 02c50efe08 block: Add bdrv_aio_cancel_async
This is the async version of bdrv_aio_cancel, which doesn't block the
caller. It guarantees that the cb is called either before returning or
some time later.

bdrv_aio_cancel can base on bdrv_aio_cancel_async, later we can convert
all .io_cancel implementations to .io_cancel_async, and the aio_poll is
the common logic. In the end, .io_cancel can be dropped.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22 11:38:58 +01:00
Fam Zheng f197fe2b2c block: Add refcnt in BlockDriverAIOCB
This will be useful in synchronous cancel emulation with
bdrv_aio_cancel_async.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22 11:38:57 +01:00
Luiz Capitulino 624ff5736e block: extend BLOCK_IO_ERROR with reason string
BLOCK_IO_ERROR events are logged by libvirt, which helps with
post mortem analysis of guests. However, one information that
we miss today is a human readable string describing the cause
of the I/O error.

This commit adds that string it to BLOCK_IO_ERROR. Note that
this string is a debugging aid for humans, meaning that it
should not parsed by applications.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-11 17:14:13 +02:00
Benoît Canet 5366d0c8bc block: Make the block accounting functions operate on BlockAcctStats
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: Benoît Canet <benoit.canet@nodalink.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-10 10:41:29 +02:00
Benoît Canet 5e5a94b605 block: Extract the block accounting code
The plan is to add new accounting metrics (latency, invalid requests, failed
requests, queue depth) and block.c is overpopulated so it will be better to work
in a separate module.

Moreover the long term plan is to have statistics in each of the BDS of the graph
for metrology purpose; this means that the device model statistics must move from
the topmost BDS to the device model.

So we need to decouple the statistic code from BlockDriverState.

This is another argument for the extraction of the code in a separate module.

CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Benoit Canet <benoit@irqsave.net>
CC: Fam Zheng <famz@redhat.com>
CC: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
CC: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Benoît Canet <benoit.canet@nodalink.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-10 10:41:29 +02:00
Benoît Canet 0ddd0ad96a block: Extract the BlockAcctStats structure
Extract the block accounting statistics into a structure so the block device
models can hold them in the future.

CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Eric Blake <eblake@redhat.com>

Signed-off-by: Benoît Canet <benoit.canet@nodalink.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-10 10:41:29 +02:00
Luiz Capitulino c7c2ff0c7e block: extend BLOCK_IO_ERROR event with nospace indicator
Management software, such as RHEV's vdsm, want to be able to allocate
disk space on demand. The basic use case is to start a VM with a small
disk and then the disk is enlarged when QEMU hits a ENOSPC condition.

To this end, the management software has to be notified when QEMU
encounters ENOSPC. The solution implemented by this commit is simple:
it extends the BLOCK_IO_ERROR with a 'nospace' key, which is true
when QEMU is stopped due to ENOSPC.

Note that support for querying this event is already present in
query-block by means of the 'io-status' key. Also, the new 'nospace'
BLOCK_IO_ERROR field shares the same semantics with 'io-status',
which basically means that werror= has to be set to either
'stop' or 'enospc' to enable 'nospace'.

Finally, this commit also updates the 'io-status' key doc in the
schema with a list of supported device models.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-10 10:41:29 +02:00
Liu Yuan 6bb4515849 block: kill tail whitespace in block.c
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-08 11:12:42 +01:00
Stefan Hajnoczi 391827eb10 block: fix overlapping multiwrite requests
When request A is a strict superset of request B:

  AAAAAAAA
    BBBB

multiwrite_merge() merges them as follows:

  AABBBB

The tail of request A should have been included:

  AABBBBAA

This patch fixes data loss but this code path is probably rare.  Since
guests cannot assume ordering between in-flight requests, few
applications submit overlapping write requests.

Reported-by: Slava Pestov <sviatoslav.pestov@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-29 14:09:43 +01:00
Max Reitz 33384421b3 block: Add AIO context notifiers
If a long-running operation on a BDS wants to always remain in the same
AIO context, it somehow needs to keep track of the BDS changing its
context. This adds a function for registering callbacks on a BDS which
are called whenever the BDS is attached or detached from an AIO context.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-29 10:48:45 +01:00
Stefan Hajnoczi ada4240103 block: sort formats alphabetically in bdrv_iterate_format()
Format names are best consumed in alphabetical order.  This makes
human-readable output easy to produce.

bdrv_iterate_format() already has an array of format strings.  Sort them
before invoking the iteration callback.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
2014-08-28 13:42:25 +01:00
Max Reitz 91af701412 block: Add bdrv_refresh_filename()
Some block devices may not have a filename in their BDS; and for some,
there may not even be a normal filename at all. To work around this, add
a function which tries to construct a valid filename for the
BDS.filename field.

If a filename exists or a block driver is able to reconstruct a valid
filename (which is placed in BDS.exact_filename), this can directly be
used.

If no filename can be constructed, we can still construct an options
QDict which is then converted to a JSON object and prefixed with the
"json:" pseudo protocol prefix. The QDict is placed in
BDS.full_open_options.

For most block drivers, this process can be done automatically; those
that need special handling may define a .bdrv_refresh_filename() method
to fill BDS.exact_filename and BDS.full_open_options themselves.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-20 14:31:56 +02:00
Markus Armbruster 5839e53bbc block: Use g_new() & friends where that makes obvious sense
g_new(T, n) is neater than g_malloc(sizeof(T) * n).  It's also safer,
for two reasons.  One, it catches multiplication overflowing size_t.
Two, it returns T * rather than void *, which lets the compiler catch
more type errors.

Patch created with Coccinelle, with two manual changes on top:

* Add const to bdrv_iterate_format() to keep the types straight

* Convert the allocation in bdrv_drop_intermediate(), which Coccinelle
  inexplicably misses

Coccinelle semantic patch:

    @@
    type T;
    @@
    -g_malloc(sizeof(T))
    +g_new(T, 1)
    @@
    type T;
    @@
    -g_try_malloc(sizeof(T))
    +g_try_new(T, 1)
    @@
    type T;
    @@
    -g_malloc0(sizeof(T))
    +g_new0(T, 1)
    @@
    type T;
    @@
    -g_try_malloc0(sizeof(T))
    +g_try_new0(T, 1)
    @@
    type T;
    expression n;
    @@
    -g_malloc(sizeof(T) * (n))
    +g_new(T, n)
    @@
    type T;
    expression n;
    @@
    -g_try_malloc(sizeof(T) * (n))
    +g_try_new(T, n)
    @@
    type T;
    expression n;
    @@
    -g_malloc0(sizeof(T) * (n))
    +g_new0(T, n)
    @@
    type T;
    expression n;
    @@
    -g_try_malloc0(sizeof(T) * (n))
    +g_try_new0(T, n)
    @@
    type T;
    expression p, n;
    @@
    -g_realloc(p, sizeof(T) * (n))
    +g_renew(T, p, n)
    @@
    type T;
    expression p, n;
    @@
    -g_try_realloc(p, sizeof(T) * (n))
    +g_try_renew(T, p, n)

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-20 11:51:28 +02:00
Max Reitz 908bcd540f block: Catch !bs->drv in bdrv_check()
qemu-img check calls bdrv_check() twice if the first run repaired some
inconsistencies. If the first run however again triggered corruption
prevention (on qcow2) due to very bad inconsistencies, bs->drv may be
NULL afterwards. Thus, bdrv_check() should check whether bs->drv is set.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15 15:07:16 +02:00
Kevin Wolf 857d4f46c3 block: Handle failure for potentially large allocations
Some code in the block layer makes potentially huge allocations. Failure
is not completely unexpected there, so avoid aborting qemu and handle
out-of-memory situations gracefully.

This patch addresses bounce buffer allocations in block.c. While at it,
convert bdrv_commit() from plain g_malloc() to qemu_try_blockalign().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15 15:07:15 +02:00
Kevin Wolf 7d2a35cc92 block: Introduce qemu_try_blockalign()
This function returns NULL instead of aborting when an allocation fails.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15 15:07:15 +02:00
Jeff Cody 9a4d5ca607 block: allow bdrv_unref() to be passed NULL pointers
If bdrv_unref() is passed a NULL BDS pointer, it is safe to
exit with no operation.  This will allow cleanup code to blindly
call bdrv_unref() on a BDS that has been initialized to NULL.

Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15 15:07:14 +02:00
Stefan Hajnoczi 2a87151fb2 block: bump coroutine pool size for drives
When a BlockDriverState is associated with a storage controller
DeviceState we expect guest I/O.  Use this opportunity to bump the
coroutine pool size by 64.

This patch ensures that the coroutine pool size scales with the number
of drives attached to the guest.  It should increase coroutine pool
usage (which makes qemu_coroutine_create() fast) without hogging too
much memory when fewer drives are attached.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-08-15 15:07:14 +02:00
Markus Armbruster 52bf1e722d block: Avoid bdrv_get_geometry() where errors should be detected
bdrv_get_geometry() hides errors.  Use bdrv_nb_sectors() or
bdrv_getlength() instead where that's obviously inappropriate.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15 15:07:13 +02:00
Markus Armbruster 75d3d21f9e block: Drop superfluous aligning of bdrv_getlength()'s value
It returns a multiple of the sector size.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15 15:07:13 +02:00
Markus Armbruster 57322b7811 block: Use bdrv_nb_sectors() where sectors, not bytes are wanted
Instead of bdrv_getlength().

Aside: a few of these callers don't handle errors.  I didn't
investigate whether they should.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15 15:07:13 +02:00
Markus Armbruster 30a7f2fc91 block: Use bdrv_nb_sectors() in bdrv_co_get_block_status()
Instead of bdrv_getlength().

Replace variables length, length2 by total_sectors, nb_sectors2.
Bonus: use total_sectors instead of the slightly unclean
bs->total_sectors.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15 15:07:13 +02:00
Markus Armbruster 4049082c4b block: Use bdrv_nb_sectors() in bdrv_aligned_preadv()
Instead of bdrv_getlength().  Eliminate variable len.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15 15:07:13 +02:00
Markus Armbruster d32f7c101b block: Use bdrv_nb_sectors() in bdrv_make_zero()
Instead of bdrv_getlength().

Variable target_size is initially in bytes, then changes meaning to
sectors.  Ugh.  Replace by target_sectors.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15 15:07:13 +02:00
Markus Armbruster 65a9bb25d6 block: New bdrv_nb_sectors()
A call to retrieve the image size converts between bytes and sectors
several times:

* BlockDriver method bdrv_getlength() returns bytes.

* refresh_total_sectors() converts to sectors, rounding up, and stores
  in total_sectors.

* bdrv_getlength() converts total_sectors back to bytes (now rounded
  up to a multiple of the sector size).

* Callers wanting sectors rather bytes convert it right back.
  Example: bdrv_get_geometry().

bdrv_nb_sectors() provides a way to omit the last two conversions.
It's exactly bdrv_getlength() with the conversion to bytes omitted.
It's functionally like bdrv_get_geometry() without its odd error
handling.

Reimplement bdrv_getlength() and bdrv_get_geometry() on top of
bdrv_nb_sectors().

The next patches will convert some users of bdrv_getlength() to
bdrv_nb_sectors().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15 15:07:12 +02:00
Kevin Wolf 3baca89139 block: Add Error argument to bdrv_refresh_limits()
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-18 13:18:43 +01:00
Kevin Wolf 8eb029c26e block: Assert qiov length matches request length
At least raw-posix relies on this because it can allocate bounce buffers
based on the request length, but access it using all of the qiov entries
later.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-07-14 12:03:20 +02:00
Kevin Wolf 33f461e0c5 block: Make qiov match the request size until EOF
If a read request goes across EOF, the block driver sees a shortened
request that stops at EOF (the rest is memsetted in block.c), however
the original qiov was used for this request.

This patch makes the qiov size match the request size, avoiding a
potential buffer overflow in raw-posix.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-07-14 12:03:20 +02:00
Paolo Bonzini b47ec2c456 block: prefer aio_poll to qemu_aio_wait
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-07-09 15:50:11 +02:00
Kevin Wolf 01fb2705bd block: Fix bdrv_is_allocated() return value
bdrv_is_allocated() should return either 0 or 1 in successful cases.
We're lucky that currently, the callers that rely on this (e.g. because
they check for ret == 1) don't seem to break badly. They just might skip
some optimisation or in the case of qemu-io 'map' print separate lines
where a single line would suffice. In theory, a wrong allocation status
could lead to image corruption with certain operations, so let's fix
this quickly.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-07-09 15:50:11 +02:00
Ming Lei 448ad91db4 block: block: introduce APIs for submitting IO as a batch
This patch introduces three APIs so that following
patches can support queuing I/O requests and submitting them
as a batch for improving I/O performance.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-07 11:05:17 +02:00
Jeff Cody 54e2690090 block: extend block-commit to accept a string for the backing file
On some image chains, QEMU may not always be able to resolve the
filenames properly, when updating the backing file of an image
after a block commit.

For instance, certain relative pathnames may fail, or drives may
have been specified originally by file descriptor (e.g. /dev/fd/???),
or a relative protocol pathname may have been used.

In these instances, QEMU may lack the information to be able to make
the correct choice, but the user or management layer most likely does
have that knowledge.

With this extension to the block-commit api, the user is able to change
the backing file of the overlay image as part of the block-commit
operation.

This allows the change to be 'safe', in the sense that if the attempt
to write the overlay image metadata fails, then the block-commit
operation returns failure, without disrupting the guest.

If the commit top is the active layer, then specifying the backing
file string will be treated as an error (there is no overlay image
to modify in that case).

If a backing file string is not specified in the command, the backing
file string to use is determined in the same manner as it was
previously.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01 10:47:01 +02:00
Jeff Cody 5a6684d2b9 block: add helper function to determine if a BDS is in a chain
This is a small helper function, to determine if 'base' is in the
chain of BlockDriverState 'top'.  It returns true if it is in the chain,
and false otherwise.

If either argument is NULL, it will also return false.

Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01 10:47:01 +02:00
Jeff Cody 4caf0fcd45 block: simplify bdrv_find_base() and bdrv_find_overlay()
This simplifies the function bdrv_find_overlay().  With this change,
bdrv_find_base() is just a subset of usage of bdrv_find_overlay(),
so this also takes advantage of that.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01 10:15:34 +02:00
Chen Gang 6b8aeca574 block.c: Don't return success for bdrv_append_temp_snapshot() failure
When failure occurs, 'ret' need be set, or may return 0 to indicate
success. Previously, an error was set in errp, but 0 was returned
anyway. So let bdrv_append_temp_snapshot() return an error code and
use that for the bdrv_open() return value.

Also, error_propagate() need be called only one time within a function.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27 20:00:00 +02:00
Benoît Canet 09158f00e0 block: Add replaces argument to drive-mirror
drive-mirror will bdrv_swap the new BDS named node-name with the one
pointed by replaces when the mirroring is finished.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27 20:00:00 +02:00
Jeff Cody 9c75e168bc block: check for RESIZE blocker in the QMP command, not bdrv_truncate()
If we check for the RESIZE blocker in bdrv_truncate(), that means a
commit will fail if the overlay layer is larger than the base, due to
the backing blocker.

This is a regression in behavior from 2.0; currently, commit will try to
grow the size of the base image to match the overlay size, if the
overlay size is larger.

By moving this into the QMP command qmp_block_resize(), it allows
usage of bdrv_truncate() within block jobs.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27 11:37:35 +02:00
Kevin Wolf 20cca275c6 block: Remove a special case for protocols
The only semantic change is that bs->open_flags gets BDRV_O_PROTOCOL set
now. This isn't useful, but it doesn't hurt either. The code that was
previously skipped by 'goto done' is automatically disabled because
protocol drivers don't support backing files (and if they did, this
would probably be a fix) and can't have snapshot_flags set.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-26 13:51:01 +02:00
Kevin Wolf 8ee79e707a block: Catch backing files assigned to non-COW drivers
Since we parse backing.* options to add a backing file from the command
line when the driver didn't assign one, it has been possible to have a
backing file for e.g. raw images (it just was never accessed).

This is obvious nonsense and should be rejected.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-26 13:51:01 +02:00
Kevin Wolf 76c591b013 block: Remove second bdrv_open() recursion
This recursion was introduced in commit 505d7583 in order to allow
nesting image formats. It only ever takes effect when the user
explicitly specifies a driver name and that driver isn't suitable for
the protocol level.

We can check this earlier in bdrv_open() and if the explicitly
requested driver is a format driver, clear BDRV_O_PROTOCOL so that
another bs->file layer is opened.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-26 13:51:01 +02:00
Kevin Wolf b348f3311c block: Inline bdrv_file_open()
It doesn't do much any more, we can move the code to bdrv_open() now.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-26 13:51:01 +02:00
Kevin Wolf f4788adcb4 block: Use common driver selection code for bdrv_open_file()
This moves the bdrv_open_file() call a bit down so that it can use the
bdrv_open() code that selects the right block driver.

The code between the old and the new call site is either common code
(the error message for an unknown driver has been unified now) or
doesn't run with cleared BDRV_O_PROTOCOL (added an if block in one
place, whereas the right path was already asserted in another place)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-06-26 13:51:01 +02:00
Kevin Wolf 17b005f1d4 block: Always pass driver name through options QDict
The "driver" entry in the options QDict is now only missing if we're
opening an image with format probing.

We also catch cases now where both the drv argument and a "driver"
option is specified, e.g. by specifying -drive format=qcow2,driver=raw

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-26 13:51:01 +02:00
Kevin Wolf 5e5c4f63f4 block: Move json: parsing to bdrv_fill_options()
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-26 13:51:01 +02:00
Kevin Wolf 462f5bcf69 block: Move bdrv_fill_options() call to bdrv_open()
bs->options now contains the modified version of the options.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-26 13:51:01 +02:00
Kevin Wolf f54120ff1a block: Create bdrv_fill_options()
The idea of bdrv_fill_options() is to convert every parameter for
opening images, in particular the filename and flags, to entries in the
options QDict.

This patch starts with moving the filename parsing and driver probing
part from bdrv_file_open() to the new function.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-26 13:51:01 +02:00
Chen Gang 5db97df274 block.c: Remove useless 'buf' variable
'buf' is not used actually, so remove it and related snprintf() statement.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-06-24 20:01:24 +04:00
Wenchao Xia 5a2d2cbd88 qapi event: convert BLOCK_IO_ERROR and BLOCK_JOB_ERROR
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia a5ee7bd454 qapi event: convert DEVICE_TRAY_MOVED
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:12:27 -04:00
Wenchao Xia a589569f2f qapi: adjust existing defines
In order to let event defines use existing types later, instead of
redefine new ones, some old type defines for spice and vnc are changed,
and BlockErrorAction is moved from block.h to qapi schema. Note that
BlockErrorAction is not merged with BlockdevOnError.

At this point, VncInfo is not made a child of VncBasicInfo, because
VncBasicInfo has mandatory fields where VncInfo makes them optional.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:01:25 -04:00
Paolo Bonzini 2bd3bce8ef block: asynchronously stop the VM on I/O errors
With virtio-blk dataplane, I/O errors might occur while QEMU is
not in the main I/O thread.  However, it's invalid to call vm_stop
when we're neither in a VCPU thread nor in the main I/O thread,
even if we were to take the iothread mutex around it.

To avoid this problem, we can raise a request to the main I/O thread,
similar to what QEMU does when vm_stop is called from a CPU thread.
We know that bdrv_error_action is called from an AIO callback, and
the moment at which the callback will fire is not well-defined; it
depends on the moment at which the disk or OS finishes the operation,
which can happen at any time.  Note that QEMU is certainly not in a CPU
thread and we do not need to call cpu_stop_current() like vm_stop() does.

However, we need to ensure that any action taken by management will
result in correct detection of the error _and_ a running VM.  In particular:

- the event must be raised after the iostatus has been set, so that
"info block" will return an iostatus that matches the event.

- the VM must be stopped after the iostatus has been set, so that
"info block" will return an iostatus that matches the runstate.

The ordering between the STOP and BLOCK_IO_ERROR events is preserved;
BLOCK_IO_ERROR is documented to come first.

This makes bdrv_error_action() thread safe (assuming QMP events are,
which is attacked by a separate series).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-23 16:36:13 +08:00
Chunyan Liu c282e1fdf7 cleanup QEMUOptionParameter
Now that all backend drivers are using QemuOpts, remove all
QEMUOptionParameter related codes.

Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: Chunyan Liu <cyliu@suse.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-16 17:23:21 +08:00
Chunyan Liu 83d0521a1e change block layer to support both QemuOpts and QEMUOptionParamter
Change block layer to support both QemuOpts and QEMUOptionParameter.
After this patch, it will change backend drivers one by one. At the end,
QEMUOptionParameter will be removed and only QemuOpts is kept.

Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: Chunyan Liu <cyliu@suse.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-16 17:23:20 +08:00
Stefan Hajnoczi 13af91ebf0 throttle: add throttle_detach/attach_aio_context()
Block I/O throttling uses timers and currently always adds them to the
main loop.  Throttling will break if bdrv_set_aio_context() is used to
move a BlockDriverState to a different AioContext.

This patch adds throttle_detach/attach_aio_context() interfaces so the
throttling timers and uses them to move timers to the new AioContext.
Note that bdrv_set_aio_context() already drains all requests so we're
sure no throttled requests are pending.

The test cases need to be updated since the throttle_init() interface
has changed.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-06-04 09:56:12 +02:00
Stefan Hajnoczi dcd042282d block: add bdrv_set_aio_context()
Up until now all BlockDriverState instances have used the QEMU main loop
for fd handlers, timers, and BHs.  This is not scalable on SMP guests
and hosts so we need to move to a model with multiple event loops on
different host CPUs.

bdrv_set_aio_context() assigns the AioContext event loop to use for a
particular BlockDriverState.  It first detaches the entire
BlockDriverState graph from the current AioContext and then attaches to
the new AioContext.

This function will be used by virtio-blk data-plane to assign a
BlockDriverState to its IOThread AioContext.  Make
bdrv_aio_set_context() public since data-plane should not include
block_int.h.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-04 09:56:11 +02:00
Stefan Hajnoczi 9b536adcbe block: acquire AioContext in bdrv_drain_all()
Modify bdrv_drain_all() to take into account that BlockDriverState
instances may be running in different AioContexts.

This patch changes the implementation of bdrv_drain_all() while
preserving the semantics.  Previously kicking throttled requests and
checking for pending requests were done across all BlockDriverState
instances in sequence.  Now we process each BlockDriverState in turn,
making sure to acquire and release its AioContext.

This prevents race conditions between the thread executing
bdrv_drain_all() and the thread running the AioContext.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-04 09:56:11 +02:00
Stefan Hajnoczi ed78cda3de block: acquire AioContext in bdrv_*_all()
bdrv_close_all(), bdrv_commit_all(), bdrv_flush_all(),
bdrv_invalidate_cache_all(), and bdrv_clear_incoming_migration_all() are
called by main loop code and touch all BlockDriverState instances.

Some BlockDriverState instances may be running in another AioContext.
Make sure to acquire the AioContext before closing the BlockDriverState.

This will protect against race conditions once virtio-blk data-plane is
using the BlockDriverState from another AioContext event loop.

Note that this patch does not convert bdrv_drain_all() yet since that
conversion is non-trivial.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-04 09:56:11 +02:00
Stefan Hajnoczi 2572b37a47 block: use BlockDriverState AioContext
Drop the assumption that we're using the main AioContext.  Convert
qemu_aio_wait() to aio_poll() and qemu_bh_new() to aio_bh_new() so the
BlockDriverState AioContext is used.

Note there is still one qemu_aio_wait() left in bdrv_create() but we do
not have a BlockDriverState there and only main loop code invokes this
function.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-04 09:56:11 +02:00
Markus Armbruster b20e61e0d5 block: Plug memory leak on brv_open_image() error path
Introduced in commit da557a.  Spotted by Coverity.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-05-30 14:26:54 +02:00
Fam Zheng ce782938b8 block: Drop redundant bdrv_refresh_limits
The above bdrv_set_backing_hd already does this.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-28 14:28:46 +02:00
Fam Zheng 826b6ca0b0 block: Add backing_blocker in BlockDriverState
This makes use of op_blocker and blocks all the operations except for
commit target, on each BlockDriverState->backing_hd.

The asserts for op_blocker in bdrv_swap are removed because with this
change, the target of block commit has at least the backing blocker of
its child, so the assertion is not true. Callers should do their check.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-28 14:28:46 +02:00
Fam Zheng 920beae103 block: Use bdrv_set_backing_hd everywhere
We need to handle the coming backing_blocker properly, so don't open
code the assignment, instead, call bdrv_set_backing_hd to change
backing_hd.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-28 14:28:46 +02:00
Fam Zheng 8d24cce1e3 block: Add bdrv_set_backing_hd()
This is the common but non-trivial steps to assign or change the
backing_hd of BDS.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-28 14:28:46 +02:00
Fam Zheng 3718d8ab65 block: Replace in_use with operation blocker
This drops BlockDriverState.in_use with op_blockers:

  - Call bdrv_op_block_all in place of bdrv_set_in_use(bs, 1).

  - Call bdrv_op_unblock_all in place of bdrv_set_in_use(bs, 0).

  - Check bdrv_op_is_blocked() in place of bdrv_in_use(bs).

    The specific types are used, e.g. in place of starting block backup,
    bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP, ...).

    There is one exception in block_job_create, where
    bdrv_op_blocker_is_empty() is used, because we don't know the operation
    type here. This doesn't matter because in a few commits away we will drop
    the check and move it to callers that _do_ know the type.

  - Check bdrv_op_blocker_is_empty() in place of assert(!bs->in_use).

Note: there is only bdrv_op_block_all and bdrv_op_unblock_all callers at
this moment. So although the checks are specific to op types, this
changes can still be seen as identical logic with previously with
in_use. The difference is error message are improved because of blocker
error info.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-28 14:28:46 +02:00
Fam Zheng fbe40ff780 block: Introduce op_blockers to BlockDriverState
BlockDriverState.op_blockers is an array of lists with BLOCK_OP_TYPE_MAX
elements. Each list is a list of blockers of an operation type
(BlockOpType), that marks this BDS as currently blocked for a certain
type of operation with reason errors stored in the list. The rule of
usage is:

 * BDS user who wants to take an operation should check if there's any
   blocker of the type with bdrv_op_is_blocked().

 * BDS user who wants to block certain types of operation, should call
   bdrv_op_block (or bdrv_op_block_all to block all types of operations,
   which is similar to the existing bdrv_set_in_use()).

 * A blocker is only referenced by op_blockers, so the lifecycle is
   managed by caller, and shouldn't be lost until unblock, so typically
   a caller does these:

   - Allocate a blocker with error_setg or similar, call bdrv_op_block()
     to block some operations.
   - Hold the blocker, do his job.
   - Unblock operations that it blocked, with the same reason pointer
     passed to bdrv_op_unblock().
   - Release the blocker with error_free().

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-28 14:28:46 +02:00
Peter Lieven 465bee1da8 block: optimize zero writes with bdrv_write_zeroes
this patch tries to optimize zero write requests
by automatically using bdrv_write_zeroes if it is
supported by the format.

This significantly speeds up file system initialization and
should speed zero write test used to test backend storage
performance.

I ran the following 2 tests on my internal SSD with a
50G QCOW2 container and on an attached iSCSI storage.

a) mkfs.ext4 -E lazy_itable_init=0,lazy_journal_init=0 /dev/vdX

QCOW2         [off]     [on]     [unmap]
-----
runtime:       14secs    1.1secs  1.1secs
filesize:      937M      18M      18M

iSCSI         [off]     [on]     [unmap]
----
runtime:       9.3s      0.9s     0.9s

b) dd if=/dev/zero of=/dev/vdX bs=1M oflag=direct

QCOW2         [off]     [on]     [unmap]
-----
runtime:       246secs   18secs   18secs
filesize:      51G       192K     192K
throughput:    203M/s    2.3G/s   2.3G/s

iSCSI*        [off]     [on]     [unmap]
----
runtime:       8mins     45secs   33secs
throughput:    106M/s    1.2G/s   1.6G/s
allocated:     100%      100%     0%

* The storage was connected via an 1Gbit interface.
  It seems to internally handle writing zeroes
  via WRITESAME16 very fast.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-05-19 13:42:27 +02:00
Max Reitz 4993f7ea7e block: Allow JSON filenames
If the filename given to bdrv_open() is prefixed with "json:", parse the
rest as a JSON object and merge the result into the options QDict. If
there are conflicts, the options QDict takes precedence.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-05-19 11:36:49 +02:00
Kevin Wolf e88ae2264d block: Fix bdrv_is_allocated() for short backing files
bdrv_is_allocated() shouldn't return true for sectors that are
unallocated, but after the end of a short backing file, even though
such sectors are (correctly) marked as containing zeros.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-05-19 11:36:48 +02:00
Kevin Wolf b1e6fc0817 block: Fix open flags with BDRV_O_SNAPSHOT
The immediately visible effect of this patch is that it fixes committing
a temporary snapshot to its backing file. Previously, it would fail with
a "permission denied" error because bdrv_inherited_flags() forced the
backing file to be read-only, ignoring the r/w reopen of bdrv_commit().

The bigger problem this revealed is that the original open flags must
actually only be applied to the temporary snapshot, and the original
image file must be treated as a backing file of the temporary snapshot
and get the right flags for that.

Reported-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-09 20:57:31 +02:00
Kevin Wolf f1f25a2e2e block: Fix open_flags in bdrv_reopen()
Use the same function as bdrv_open() for determining what the right
flags for bs->file are. Without doing this, a reopen means that
bs->file loses BDRV_O_CACHE_WB or BDRV_O_UNMAP if bs doesn't have it as
well.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-30 11:05:00 +02:00
Kevin Wolf 7e3d98dd31 Revert "block: another bdrv_append fix"
This reverts commit 3a389e7926. The commit
was wrong and what it tried to fix just works today without any change.

What the commit tried to fix:

    When creating live snapshots, the new image file is opened with
    BDRV_O_NO_BACKING because the whole backing chain is already opened.
    It is then appended to the chain using bdrv_append(). The result of
    this was that the image had a backing file, but BDRV_O_NO_BACKING
    was still set. This is obviously inconsistent.

    There used to be some places in qemu that closed and image and then
    opened it again, with its old flags (a bdrv_open()/close() sequence
    involves reopening the whole backing file chain, too). In this case
    the BDRV_O_NO_BACKING flag meant that the backing chain wasn't
    reopened and only the top layer was left.

    (Most, but not all of these places are replaced by bdrv_reopen()
    today, which doesn't touch the backing files at all.)

    Other places that looked at bs->open_flags weren't interested in
    BDRV_O_NO_BACKING, so no breakage there.

What it actually did:

    The commit moved the BDRV_O_NO_BACKING away to the backing file.
    Because the bdrv_open()/close() sequences only looked at the flags
    of the top level BlockDriverState and used it for the whole chain,
    the flag didn't hurt there any more. Obviously, it is still
    inconsistent because the backing file may have another backing file,
    but without practical impact.

    At the same time, it swapped all other flags. This is practically
    irrelevant as long as live snapshots only allow opening the new
    layer with the same flags as the old top layer. It still doesn't
    make any sense, and it is a time bomb that explodes as soon as the
    flags can differ.

    bdrv_append_temp_snapshot() is such a case: It adds the new flag
    BDRV_O_TEMPORARY for the temporary snapshot. The swapping of commit
    3a389e79 results in the following nonsensical configuration:

    bs->open_flags:                     BDRV_O_TEMPORARY cleared
    bs->file->open_flags:               BDRV_O_TEMPORARY set
    bs->backing_hd->open_flags:         BDRV_O_TEMPORARY set
    bs->backing_hd->file->open_flags:   BDRV_O_TEMPORARY cleared

    We're still lucky because the format layer ignores the flag and the
    protocol layer happens to get the right value, but sooner or later
    this is bound to go wrong...

What the right fix would have been:

    Simply clear the BDRV_O_NO_BACKING flag when the BlockDriverState is
    appended to an existing backing file chain, because now it does have
    a backing file.

    Commit 4ddc07ca already implemented this silently in bdrv_append(),
    so we don't have to come up with a new fix.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-30 11:05:00 +02:00
Kevin Wolf 8bfea15dda block: Unlink temporary files in raw-posix/win32
Instead of having unlink() calls in the generic block layer, where we
aren't even guarateed to have a file name, move them to those block
drivers that are actually used and that always have a filename. Gets us
rid of some #ifdefs as well.

The patch also converts bs->is_temporary to a new BDRV_O_TEMPORARY open
flag so that it is inherited in the protocol layer and the raw-posix and
raw-win32 drivers can unlink the file.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-30 11:05:00 +02:00
Kevin Wolf 5669b44de5 block: Remove BDRV_O_COPY_ON_READ for bs->file
Copy on Read makes sense on the format level where backing files are
implemented, but it's not required on the protocol level. While it
shouldn't actively break anything to have COR enabled on both layers,
needless serialisation and allocation checks may impact performance.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-30 11:05:00 +02:00
Kevin Wolf 317fc44ef2 block: Create bdrv_backing_flags()
Instead of manipulation flags inline, move the derivation of the flags
of a backing file into a new function next to the existing functions
that derive flags for bs->file and for the block driver open function.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-30 11:05:00 +02:00
Kevin Wolf 0b50cc8853 block: Create bdrv_inherited_flags()
Instead of having bdrv_open_flags() as a function that creates flags for
several unrelated places and then adding open-coded flags on top, create
a new function that derives the flags for bs->file from the flags for bs.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-30 11:05:00 +02:00
Jeff Cody e855e4fb7b block: Ignore duplicate or NULL format_name in bdrv_iterate_format
Some block drivers have multiple BlockDriver instances with identical
format_name fields (e.g. gluster, nbd).

Both qemu-img and qemu will use bdrv_iterate_format() to list the
supported formats when a help option is invoked.  As protocols and
formats may register multiple drivers, redundant listings of formats
occur (e.g., "Supported formats: ... gluster gluster gluster gluster ...
").

Since the list of driver formats will be small, this performs a simple
linear search on format_name, and ignores any duplicates.

The end result change is that the iterator will no longer receive
duplicate string names, nor will it receive NULL pointers.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-04-29 11:58:07 +02:00
Markus Armbruster 0fb6395c0c Use error_is_set() only when necessary (again)
error_is_set(&var) is the same as var != NULL, but it takes
whole-program analysis to figure that out.  Unnecessarily hard for
optimizers, static checkers, and human readers.  Commit 84d18f0 dumbed
it down to obvious, but a few more have crept in since, and
documentation was overlooked.  Dumb these down, too.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-25 18:05:06 +02:00
Benoît Canet 1ba4b6a553 block: Prevent coroutine stack overflow when recursing in bdrv_open_backing_file.
In 1.7.1 qcow2_create2 reopen the file for flushing without the BDRV_O_NO_BACKING
flags.

As a consequence the code would recursively open the whole backing chain.

These three stack arrays would pile up through the recursion and lead to a coroutine
stack overflow.

Convert these array to malloced buffers in order to streamline the coroutine
footprint.

Symptoms where freezes or segfaults on production machines while taking QMP externals
snapshots. The overflow disturbed coroutine switching.

[Resolved conflicts on qemu.git/master since the patch was against v1.7.1
--Stefan]

Signed-off-by: Benoit Canet <benoit.canet@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-25 18:05:05 +02:00
Kevin Wolf f2d953ec31 block: Catch duplicate IDs in bdrv_new()
Since commit f298d071, block devices added with blockdev-add don't have
a QemuOpts around in dinfo->opts. Consequently, we can't rely any more
on QemuOpts catching duplicate IDs for block devices.

This patch adds a new check for duplicate IDs to bdrv_new(), and moves
the existing check that the ID isn't already taken for a node-name there
as well.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-04-22 12:00:28 +02:00
Kevin Wolf 98522f63f4 block: Add errp to bdrv_new()
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: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2014-04-22 12:00:20 +02:00
Kevin Wolf 636ea3708c block: Remove -errno return value from bdrv_assign_node_name
It takes an errp argument. That's enough for error handling.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-04-22 11:57:02 +02:00
Fam Zheng b8afb520e4 block: Handle error of bdrv_getlength in bdrv_create_dirty_bitmap
bdrv_getlength could fail, check the return value before using it.
Return NULL and set errno if it fails. Callers are updated to handle
the error case.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-04-22 11:57:02 +02:00
Kevin Wolf 9ce10c0bdc block: Check bdrv_getlength() return value in bdrv_make_zero()
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-22 11:57:02 +02:00
Kevin Wolf da15ee5134 block: Catch integer overflow in bdrv_rw_co()
Insanely large requests could cause an integer overflow in
bdrv_rw_co() while converting sectors to bytes. This patch catches the
problem and returns an error (if we hadn't overflown the integer here,
bdrv_check_byte_request() would have rejected the request, so we're not
breaking anything that was supposed to work before).

We actually do have a test case that triggers behaviour where we
accidentally let such a request pass, so that it would return success,
but read 0 bytes instead of the requested 4 GB. It fails now like it
should.

If the vdi block driver wants to be able to deal with huge images, it
can't read the whole block bitmap at once into memory like it does
today, but needs to use a metadata cache like qcow2 does.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-04-22 11:57:02 +02:00
Kevin Wolf 1dd3a44753 block: Limit size to INT_MAX in bdrv_check_byte_request()
Commit 8f4754ed intended to protect against integer overflow bugs in
block drivers by making sure that a single request that is passed to
drivers is no longer than INT_MAX bytes.

However, meanwhile there are some callers that don't use that code path
any more but call bdrv_check_byte_request() directy, so let's add a
check there as well.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-22 11:57:02 +02:00
Kevin Wolf 54db38a479 block: Fix nb_sectors check in bdrv_check_byte_request()
nb_sectors is signed, check for negative values.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-22 11:57:02 +02:00
Kevin Wolf f187743acd block: Check bdrv_getlength() return value in bdrv_append_temp_snapshot()
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-04 19:35:52 +02:00
Kevin Wolf b998875dcf block: Fix snapshot=on for protocol parsed from filename
Since commit 9fd3171a, BDRV_O_SNAPSHOT uses an option QDict to specify
the originally requested image as the backing file of the newly created
temporary snapshot. This means that the filename is stored in
"file.filename", which is an option that is not parsed for protocol
names. Therefore things like -drive file=nbd:localhost:10809 were
broken because it looked for a local file with the literal name
'nbd:localhost:10809'.

This patch changes the way BDRV_O_SNAPSHOT works once again. We now open
the originally requested image as normal, and then do a similar
operation as for live snapshots to put the temporary snapshot on top.
This way, both driver specific options and parsed filenames work.

As a nice side effect, this results in code movement to factor
bdrv_append_temp_snapshot() out. This is a good preparation for moving
its call to drive_init() and friends eventually.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-04 19:35:51 +02:00
Kevin Wolf e3fa4bfa72 block: Don't parse 'filename' option
When using the QDict option 'filename', it is supposed to be interpreted
literally. The code did correctly avoid guessing the protocol from any
string before the first colon, but it still called bdrv_parse_filename()
which would, for example, incorrectly remove a 'file:' prefix in the
raw-posix driver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-04-04 17:10:25 +02:00
Kevin Wolf 8f4754ede5 block: Limit request size (CVE-2014-0143)
Limiting the size of a single request to INT_MAX not only fixes a
direct integer overflow in bdrv_check_request() (which would only
trigger bad behaviour with ridiculously huge images, as in close to
2^64 bytes), but can also prevent overflows in all block drivers.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01 15:22:35 +02:00
Kevin Wolf 5a8a30db47 block: Add error handling to bdrv_invalidate_cache()
If it returns an error, the migrated VM will not be started, but qemu
exits with an error message.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-03-19 09:39:41 +01:00
Markus Armbruster c3adb58fe0 blockdev: Refuse to open encrypted image unless paused
Opening an encrypted image takes an additional step: setting the key.
Between open and the key set, the image must not be used.

We have some protection against accidental use in place: you can't
unpause a guest while we're missing keys.  You can, however, hot-plug
block devices lacking keys into a running guest just fine, or insert
media lacking keys.  In the latter case, notifying the guest of the
insert is delayed until the key is set, which may suffice to protect
at least some guests in common usage.

This patch makes the protection apply in more cases, in a rather
heavy-handed way: it doesn't let you open encrypted images unless
we're in a paused state.

It doesn't extend the protection to users other than the guest (block
jobs?).  Use of runstate_check() from block.c is disgusting.  Best I
can do right now.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-14 16:24:42 +01:00
Max Reitz 9562f69cfd block: Unlink temporary file
If the image file cannot be opened and was created as a temporary file,
it should be deleted; thus, in this case, we should jump to the
"unlink_and_fail" label and not just to "fail".

Reported-by: Benoît Canet <benoit@irqsave.net>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-13 14:42:24 +01:00
Benoît Canet b5042a3622 block: Rewrite the snapshot authorization mechanism for block filters.
This patch keep the recursive way of doing things but simplify it by giving
two responsabilities to all block filters implementors.

They will need to do two things:

-Set the is_filter field of their block driver to true.

-Implement the bdrv_recurse_is_first_non_filter method of their block driver like
it is done on the Quorum block driver. (block/quorum.c)

[Paolo Bonzini <pbonzini@redhat.com> pointed out that this patch changes
the semantics of blkverify, which now recurses down both bs->file and
s->test_file.
-- Stefan]

Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-13 14:23:27 +01:00
Max Reitz 938789ea92 block: bs->drv may be NULL in bdrv_debug_resume()
Currently, bdrv_debug_resume() requires every bs->drv in the BDS stack
to be NULL until a bs->drv with an implementation of bdrv_debug_resume()
is found. For a normal function, this would be fine, but this is a
function for debugging purposes and should therefore allow intermediate
BDS not to have a driver (i.e., be "ejected"). Otherwise, it is hard to
debug such situations.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-13 14:23:27 +01:00
Kevin Wolf 3456a8d185 block: Update image size in bdrv_invalidate_cache()
After migration has completed, we call bdrv_invalidate_cache() so that
drivers which cache some data drop their stale copy of the data and
reread it from the image file to get a new version of data that the
source modified while the migration was running.

Reloading metadata from the image file is useless, though, if the size
of the image file stays stale (this is a value that is cached for all
image formats in block.c). Reads from (meta)data after the old EOF
return only zeroes, causing image corruption.

We need to update bs->total_sectors in all layers that could potentially
have changed their size (i.e. backing files are not a concern - if they
are changed, we're in bigger trouble)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-13 14:23:27 +01:00
Kevin Wolf eb909c7f72 block: Fix error path segfault in bdrv_open()
Using an invalid option for a block device that is opened with
BDRV_O_PROTOCOL led to drv = NULL, and when trying to include the driver
name in the error message, qemu dereferenced it:

    $ x86_64-softmmu/qemu-system-x86_64 -drive file=/tmp/test.qcow2,file.foo=bar
    Segmentation fault (core dumped)

With this patch applied, the expected error message is printed:

    $ x86_64-softmmu/qemu-system-x86_64 -drive file=/tmp/test.qcow2,file.foo=bar
    qemu-system-x86_64: -drive file=/tmp/test.qcow2,file.foo=bar: could
    not open disk image /tmp/test.qcow2: Block protocol 'file' doesn't
    support the option 'foo'

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-03-06 17:29:24 +01:00
Max Reitz cd5d031e75 block: Keep "filename" option after parsing
Currently, bdrv_file_open() always removes the "filename" option from
the options QDict after bdrv_parse_filename() has been (successfully)
called. However, for drivers with bdrv_needs_filename, it makes more
sense for bdrv_parse_filename() to overwrite the "filename" option and
for bdrv_file_open() to fetch the filename from there.

Since there currently are no drivers that implement
bdrv_parse_filename() and have bdrv_needs_filename set, this does not
change current behavior.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-03-06 16:18:01 +01:00
Benoît Canet 90ce8a061b block: make bdrv_swap rebuild the bs graph node list field.
Moving only the node_name one field could lead to some inconsitencies where a
node_name was defined on a bs which was not registered in the graph node list.

bdrv_swap between a named node bs and a non named node bs would lead to this.

bdrv_make_anon would then crash because it would try to remove the bs from the
graph node list while it is not in it.

This patch remove named node bses from the graph node list before doing the swap
then insert them back.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-03-06 11:33:10 +01:00
Kevin Wolf 47ea2de2d6 block: Fix bs->request_alignment assertion for bs->sg=1
For sg backends, bs->request_alignment is meaningless and may be 0.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-05 16:58:37 +01:00
Amit Shah 69bef7931e block: use /var/tmp instead of /tmp for -snapshot
If TMPDIR is not specified, the default was to use /tmp for the working
copy of the block devices.  Update this to /var/tmp instead, so systems
using tmp-on-tmpfs don't end up inadvertently using RAM for the block
device.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-02-28 18:59:07 +01:00
Max Reitz f7d9fd8c72 block: Remove bdrv_open_image()'s force_raw option
This option is now unnecessary since specifying BDRV_O_PROTOCOL as flag
will do exactly the same.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21 21:02:22 +01:00
Max Reitz 5acd9d81e1 block: Reuse success path from bdrv_open()
The fail and success paths of bdrv_file_open() may be further shortened
by reusing code already existent in bdrv_open(). This includes
bdrv_file_open() not taking the reference to options which allows the
removal of QDECREF(options) in that function.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21 21:02:22 +01:00
Max Reitz 5469a2a688 block: Handle bs->options in bdrv_open() only
The fail paths of bdrv_file_open() and bdrv_open() naturally exhibit
similarities, thus it is possible to reuse the one from bdrv_open() and
shorten the one in bdrv_file_open() accordingly.

Also, setting bs->options in bdrv_file_open() is not necessary if it is
already done in bdrv_open().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21 21:02:22 +01:00
Max Reitz d4446eae63 block: Remove bdrv_new() from bdrv_file_open()
Change bdrv_file_open() to take a simple pointer to an already existing
BDS instead of an indirect one. The BDS will be created in bdrv_open()
if necessary.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21 21:02:22 +01:00
Max Reitz 5d12aa63c7 block: Reuse reference handling from bdrv_open()
Remove the reference parameter and the related handling code from
bdrv_file_open(), since it exists in bdrv_open() now as well.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21 21:02:22 +01:00
Max Reitz 2e40134bfd block: Make bdrv_file_open() static
Add the bdrv_open() option BDRV_O_PROTOCOL which results in passing the
call to bdrv_file_open(). Additionally, make bdrv_file_open() static and
therefore bdrv_open() the only way to call it.

Consequently, all existing calls to bdrv_file_open() have to be adjusted
to use bdrv_open() with the BDRV_O_PROTOCOL flag instead.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21 21:02:22 +01:00
Max Reitz ddf5636dc9 block: Add reference parameter to bdrv_open()
Allow bdrv_open() to handle references to existing block devices just as
bdrv_file_open() is already capable of.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21 21:02:22 +01:00
Max Reitz f67503e5bd block: Change BDS parameter of bdrv_open() to **
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: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21 21:02:21 +01:00
Kevin Wolf e6dc8a1f83 block: Fix bdrv_is_first_non_filter()
Consider top level BlockDriverStates as well.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Tested-by: Benoit Canet <benoit@irqsave.net>
2014-02-21 21:02:21 +01:00
Peter Maydell 4c0c9bbe78 Merge remote-tracking branch 'remotes/qmp-unstable/queue/qmp' into staging
* remotes/qmp-unstable/queue/qmp:
  monitor: Add object_add class argument completion.
  monitor: Add object_del id argument completion.
  monitor: Add device_add device argument completion.
  monitor: Add device_del id argument completion.
  qmp: expose list of supported character device backends
  Use error_is_set() only when necessary
  QMP: allow JSON dict arguments in qmp-shell
  hmp: migrate command (without -d) now blocks correctly

Conflicts:
	blockdev.c

[PMM: resolved trivial conflict in blockdev.c]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-02-20 12:10:23 +00:00
Markus Armbruster 84d18f065f Use error_is_set() only when necessary
error_is_set(&var) is the same as var != NULL, but it takes
whole-program analysis to figure that out.  Unnecessarily hard for
optimizers, static checkers, and human readers.  Dumb it down to
obvious.

Gets rid of several dozen Coverity false positives.

Note that the obvious form is already used in many places.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-02-17 11:57:23 -05:00
Benoît Canet 0c5e94ee83 block: Open by reference will try device then node_name.
Since we introduced node_name for named bs of the graph modify the opening by
reference to use it as a fallback.

This patch also enforce the separation of the device id and graph node
namespaces.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-02-14 18:05:39 +01:00
Benoît Canet dd67fa5052 block: Relax bdrv_lookup_bs constraints.
The following patch will reuse bdrv_lookup_bs in order to open images by
references so the rules of usage of bdrv_lookup_bs must be relaxed a bit.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-02-14 18:05:39 +01:00
Kevin Wolf e96126ffa5 block: Fix 32 bit truncation in mark_request_serialising()
On 32 bit hosts, size_t is too small for align as the bitmask
~(align - 1) will zero out the higher 32 bits of the offset.

While at it, change the local overlap_bytes variable to unsigned to
match the field in BdrvTrackedRequest.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
2014-02-09 09:12:39 +01:00
Kevin Wolf 5f5bcd80f8 block: Don't call ROUND_UP with negative values
The behaviour of the ROUND_UP macro with negative numbers isn't obvious.
It happens to do the right thing in this please, but better avoid it.

Suggested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
2014-02-09 09:12:39 +01:00
Kevin Wolf af91f9a73c block: bdrv_aligned_pwritev: Assert overlap range
This adds assertions that the request that we actually end up passing to
the block driver (which includes RMW data and has therefore potentially
been rounded to alignment boundaries) is fully covered by the
overlap_{offset,size} fields of the associated BdrvTrackedRequest.

Suggested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
2014-02-09 09:12:39 +01:00
Kevin Wolf 99c4a85ce6 block: Fix memory leaks in bdrv_co_do_pwritev()
The error path for a failure in one of the two bdrv_aligned_preadv()
calls leaked head_buf or tail_buf, respectively. This fixes the memory
leak.

Reported-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
2014-02-09 09:12:39 +01:00
Kevin Wolf 765003db02 block: Fail gracefully with missing filename
This fixes a regression introduced in commit 2a05cbe42 ('block: Allow
block devices without files'):

$ qemu-system-x86_64 -drive driver=file
qemu-system-x86_64: block.c:892: bdrv_open_common: Assertion
`!drv->bdrv_needs_filename || filename != ((void *)0)' failed.

Now the respective check must be performed not only in bdrv_file_open(),
but also in bdrv_open().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-02-09 09:12:38 +01:00
Kevin Wolf d5103588aa block: Switch bdrv_io_limits_intercept() to byte granularity
Request sizes used to be rounded down to the next sector boundary,
allowing to bypass the I/O limit. Now all requests are accounted for
with their exact byte size.

Reported-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-01-24 17:40:28 +01:00
Kevin Wolf 9e1cb96d9a qemu-iotests: Test pwritev RMW logic
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-01-24 17:40:25 +01:00
Kevin Wolf 8407d5d7e2 block: Make bdrv_pwrite() a bdrv_prwv_co() wrapper
Instead of implementing the alignment adjustment here, use the now
existing functionality of bdrv_co_do_pwritev().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-01-24 17:40:03 +01:00
Kevin Wolf a3ef657185 block: Make bdrv_pread() a bdrv_prwv_co() wrapper
Instead of implementing the alignment adjustment here, use the now
existing functionality of bdrv_co_do_preadv().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-01-24 17:40:03 +01:00
Kevin Wolf 775aa8b6e0 block: Change coroutine wrapper to byte granularity
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-01-24 17:40:03 +01:00
Kevin Wolf 28de2dcd88 block: Assert serialisation assumptions in pwritev
If a request calls wait_serialising_requests() and actually has to wait
in this function (i.e. a coroutine yield), other requests can run and
previously read data (like the head or tail buffer) could become
outdated. In this case, we would have to restart from the beginning to
read in the updated data.

However, we're lucky and don't actually need to do that: A request can
only wait in the first call of wait_serialising_requests() because we
mark it as serialising before that call, so any later requests would
wait. So as we don't wait in practice, we don't have to reload the data.

This is an important assumption that may not be broken or data
corruption will happen. Document it with some assertions.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-01-24 17:40:03 +01:00
Kevin Wolf 3b8242e0ea block: Align requests in bdrv_co_do_pwritev()
This patch changes bdrv_co_do_pwritev() to actually be what its name
promises. If requests aren't properly aligned, it performs a RMW.

Requests touching the same block are serialised against the RMW request.
Further optimisation of this is possible by differentiating types of
requests (concurrent reads should actually be okay here).

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf 6460440f34 block: Allow wait_serialising_requests() at any point
We can only have a single wait_serialising_requests() call per request
because otherwise we can run into deadlocks where requests are waiting
for each other. The same is true when wait_serialising_requests() is not
at the very beginning of a request, so that other requests can be issued
between the start of the tracking and wait_serialising_requests().

Fix this by changing wait_serialising_requests() to ignore requests that
are already (directly or indirectly) waiting for the calling request.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf 7327145f63 block: Make overlap range for serialisation dynamic
Copy on Read wants to serialise with all requests touching the same
cluster, so wait_serialising_requests() rounded to cluster boundaries.
Other users like alignment RMW will have different requirements, though
(requests touching the same sector), so make it dynamic.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf 2dbafdc012 block: Generalise and optimise COR serialisation
Change the API so that specific requests can be marked serialising. Only
these requests are checked for overlaps then.

This means that during a Copy on Read operation, not all requests
overlapping other requests are serialised any more, but only those that
actually overlap with the specific COR request.

Also remove COR from function and variable names because this
functionality can be useful in other contexts.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf ec746e10cb block: Make zero-after-EOF work with larger alignment
Odd file sizes could make bdrv_aligned_preadv() shorten the request in
non-aligned ways. Fix it by rounding to the required alignment instead
of 512 bytes.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf 65afd211c7 block: Allow waiting for overlapping requests between begin/end
Previously, it was not possible to use wait_for_overlapping_requests()
between tracked_request_begin()/end() because it would wait for itself.

Ignore the current request in the overlap check and run more of the
bdrv_co_do_preadv/pwritev code with a BdrvTrackedRequest present.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf 793ed47a7a block: Switch BdrvTrackedRequest to byte granularity
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf 6601553e27 block: Introduce bdrv_co_do_pwritev()
This is going to become the bdrv_co_do_preadv() equivalent for writes.
In this patch, however, just a function taking byte offsets is created,
it doesn't align anything yet.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf 244eadef5c block: write: Handle COR dependency after I/O throttling
First waiting for all COR requests to complete and calling the
throttling function afterwards means that the request could be delayed
and we still need to wait for the COR request even if it was issued only
after the throttled write request.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf b404f72036 block: Introduce bdrv_aligned_pwritev()
This separates the part of bdrv_co_do_writev() that needs to happen
before the request is modified to match the backend alignment, and a
part that needs to be executed afterwards and passes the request to the
BlockDriver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf 1b0288ae7f block: Introduce bdrv_co_do_preadv()
Similar to bdrv_pread(), which aligns byte-aligned request to 512 byte
sectors, bdrv_co_do_preadv() takes a byte-aligned request and aligns it
to the alignment specified in bs->request_alignment.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:02 +01:00
Kevin Wolf d0c7f642f5 block: Introduce bdrv_aligned_preadv()
This separates the part of bdrv_co_do_readv() that needs to happen
before the request is modified to match the backend alignment, and a
part that needs to be executed afterwards and passes the request to the
BlockDriver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-01-24 17:40:02 +01:00
Paolo Bonzini c25f53b06e raw: Probe required direct I/O alignment
Add a bs->request_alignment field that contains the required
offset/length alignment for I/O requests and fill it in the raw block
drivers. Use ioctls if possible, else see what alignment it takes for
O_DIRECT to succeed.

While at it, also expose the memory alignment requirements, which may be
(and in practice are) different from the disk alignment requirements.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-01-24 17:40:02 +01:00
Paolo Bonzini 1b7fd72955 block: rename buffer_alignment to guest_block_size
The alignment field is now set to the value that is promised to the
guest, rather than required by the host.  The next patches will make
QEMU aware of the host-provided values, so make this clear.

The alignment is also not about memory buffers, but about the sectors on
the disk, change the documentation of the field.

At this point, the field is set by the device emulation, but completely
ignored by the block layer.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:01 +01:00
Kevin Wolf 339064d506 block: Don't use guest sector size for qemu_blockalign()
bs->buffer_alignment is set by the device emulation and contains the
logical block size of the guest device. This isn't something that the
block layer should know, and even less something to use for determining
the right alignment of buffers to be used for the host.

The new BlockLimits field opt_mem_alignment tells the qemu block layer
the optimal alignment to be used so that no bounce buffer must be used
in the driver.

This patch may change the buffer alignment from 4k to 512 for all
callers that used qemu_blockalign() with the top-level image format
BlockDriverState. The value was never propagated to other levels in the
tree, so in particular raw-posix never required anything else than 512.

While on disks with 4k sectors direct I/O requires a 4k alignment,
memory may still be okay when aligned to 512 byte boundaries. This is
what must have happened in practice, because otherwise this would
already have failed earlier. Therefore I don't expect regressions even
with this intermediate state. Later, raw-posix can implement the hook
and expose a different memory alignment requirement.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-01-24 17:40:01 +01:00
Kevin Wolf 1ff735bdc4 block: Detect unaligned length in bdrv_qiov_is_aligned()
For an O_DIRECT request to succeed, it's not only necessary that all
base addresses in the qiov are aligned, but also that each length in it
is aligned.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-01-24 17:40:01 +01:00
Kevin Wolf 355ef4ac95 block: Update BlockLimits when they might have changed
When reopening with different flags, or when backing files disappear
from the chain, the limits may change. Make sure they get updated in
these cases.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoît Canet <benoit@irqsave.net>
2014-01-24 17:40:01 +01:00
Kevin Wolf 466ad822de block: Inherit opt_transfer_length
When there is a format driver between the backend, it's not guaranteed
that exposing the opt_transfer_length for the format driver results in
the optimal requests (because of fragmentation etc.), but it can't make
things worse, so let's just do it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoît Canet <benoit@irqsave.net>
2014-01-24 17:40:01 +01:00
Kevin Wolf d34682cd4a block: Move initialisation of BlockLimits to bdrv_refresh_limits()
This function separates filling the BlockLimits from bdrv_open(), which
allows it to call it from other operations which may change the limits
(e.g. modifications to the backing file chain or bdrv_reopen)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 17:40:01 +01:00
Kevin Wolf dabfa6cc2e block: Fix bdrv_commit return value
bdrv_commit() could return 0 or 1 on success, depending on whether or
not the last sector was allocated in the overlay and whether the overlay
format had a .bdrv_make_empty callback.

Most callers ignored it, but qemu-img commit would print an error
message while the operation actually succeeded.

Also clean up the handling of I/O errors to return the real error code
instead of -EIO.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-24 16:53:51 +01:00
Jeff Cody 72706ea4cd block: resize backing file image during offline commit, if necessary
Currently, if an image file is logically larger than its backing file,
committing it via 'qemu-img commit' will fail.

For instance, if we have a base image with a virtual size 10G, and a
snapshot image of size 20G, then committing the snapshot offline with
'qemu-img commit' will likely fail.

This will automatically attempt to resize the base image, if the
snapshot image to be committed is larger.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-24 16:12:49 +01:00
Benoît Canet 212a5a8f09 block: Create authorizations mechanism for external snapshot and resize.
Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-24 16:07:08 +01:00
Benoît Canet 12d3ba821d qmp: Allow to change password on named block driver states.
Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Fam Zheng <famz@redhat.com>

There was two candidate ways to implement named node manipulation:

1)
{ 'command': 'block_passwd', 'data': {'*device': 'str',
                                      '*node-name': 'str', 'password': 'str'}
}

2)

{ 'command': 'block_passwd', 'data': {'device': 'str',
                                      '*device-is-node': 'bool',
                                      'password': 'str'} }

Luiz proposed 1 and says 2 was an abuse of the QMP interface and proposed to
rewrite the QMP block interface for 2.0.

Luiz does not like in 1 the fact that 2 fields are optional but one of them must
be specified leading to an abuse of the QMP semantic.

Kevin argumented that 2 what a clear abuse of the device field and would not be
practical when reading fast some log file because the user would read "device"
and think that a device is manipulated when it's in fact a node name.
Documentation of 1 make it pretty clear what to do for the user.

Kevin argued that all bs are node including devices ones so 2 does not make
sense.

Kevin also argued that rewriting the QMP block interface would not make disapear
the current one.

Kevin pushed the argument that making the QAPI generator compatible with the
semantic of the operation would need a rewrite that no one has done yet.

A vote has been done on the list to elect the version to use and 1 won.

For reference the complete thread is:
"[Qemu-devel] [PATCH V4 4/7] qmp: Allow to change password on names block driver
states."

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-24 16:07:08 +01:00
Benoît Canet c13163fba1 qmp: Add QMP query-named-block-nodes to list the named BlockDriverState nodes.
Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-24 16:07:08 +01:00
Benoît Canet 6913c0c2ce block: Allow the user to define "node-name" option both on command line and QMP.
Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-24 16:06:47 +01:00
Benoît Canet dc364f4cdc block: Add bs->node_name to hold the name of a bs node of the bs graph.
Add the minimum of code to prepare for the following patches.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-24 14:33:01 +01:00
Peter Feiner d80ac658f2 block: fix backing file segfault
When a backing file is opened such that (1) a protocol is directly
used as the block driver and (2) the block driver has bdrv_file_open,
bdrv_open_backing_file segfaults. The problem arises because
bdrv_open_common returns without setting bd->backing_hd->file.

To effect (1), you seem to have to use the -F flag in qemu-img. There
are several block drivers that satisfy (2), such as "file" and "nbd".
Here are some concrete examples:

    #!/bin/bash

    echo Test file format
    ./qemu-img create -f file base.file 1m
    ./qemu-img create -f qcow2 -F file -o backing_file=base.file\
        file-overlay.qcow2
    ./qemu-img convert -O raw file-overlay.qcow2 file-convert.raw

    echo Test nbd format
    SOCK=$PWD/nbd.sock
    ./qemu-img create -f raw base.raw 1m
    ./qemu-nbd -t -k $SOCK base.raw &
    trap "kill $!" EXIT
    while ! test -e $SOCK; do sleep 1; done
    ./qemu-img create -f qcow2 -F nbd -o backing_file=nbd:unix:$SOCK\
        nbd-overlay.qcow2
    ./qemu-img convert -O raw nbd-overlay.qcow2 nbd-convert.raw

Without this patch, the two qemu-img convert commands segfault.

This is a regression that was introduced in v1.7 by
dbecebddfa.

Signed-off-by: Peter Feiner <peter@gridcentric.ca>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-22 13:47:52 +01:00
Max Reitz 505d758334 block: Allow recursive "file"s
It should be possible to use a format as a driver for a file which in
turn requires another file, i.e., nesting file formats.

Allowing nested file formats results in e.g. qcow2 BlockDriverStates
never being directly passed to bdrv_open_common() from bdrv_file_open(),
but instead being handed through bdrv_open(). This changes the error
message when trying to give a filename to qcow2, i.e. trying to use it
as a driver for the protocol level. Therefore, change the reference
output of I/O test 051 accordingly.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-22 12:07:18 +01:00
Max Reitz 054963f8f0 block: Use bdrv_open_image() in bdrv_open()
Using bdrv_open_image() instead of bdrv_file_open() directly in
bdrv_open() is easier.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-22 12:07:18 +01:00
Max Reitz da557aac18 block: Add bdrv_open_image()
Add a common function for opening images to be used for block drivers
specified through BlockdevRefs in an option QDict. The difference from
bdrv_file_open() is that this function may invoke bdrv_open() instead,
allowing auto-detection of the driver to be used; and second, it
automatically extracts the BlockdevRef from the option QDict.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-22 12:07:18 +01:00
Max Reitz 2a05cbe426 block: Allow block devices without files
blkdebug and blkverify will, in order to retain compatibility, not
support the field "file" implicitly through bdrv_open(). In order to be
able to use those drivers without giving a filename anyway, it is
necessary to be able to have block devices without files implicitly
opened by bdrv_open(). This is the case, if there was neither a file
name, a reference to an existing block device to use as a file nor
options specific to the file.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-22 12:07:17 +01:00
Max Reitz 2258e3fe20 block: Pass reference to bdrv_file_open()
With that now being possible, bdrv_open() should try to extract a block
device reference from the options and pass it to bdrv_file_open().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-22 12:07:17 +01:00
Max Reitz 72daa72eee block: Allow reference for bdrv_file_open()
Allow specifying a reference to an existing block device (by name) for
bdrv_file_open() instead of a filename and/or options.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-22 12:07:17 +01:00
Peter Lieven 3d94ce60ae block: expect get_block_status errors in bdrv_make_zero
during testing around with 4k LUNs a bad target implementation
triggert an -EIO in iscsi_get_block_status, but it got never caught
resulting in an infinite loop.

CC: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-12-13 14:49:50 +01:00
Stefan Hajnoczi 0b06ef3bdd block: clean up bdrv_drain_all() throttling comments
Since cc0681c454 ("block: Enable the new
throttling code in the block layer.") bdrv_drain_all() no longer spins.
The code used to look as follows:

  do {
      busy = qemu_aio_wait();

      /* FIXME: We do not have timer support here, so this is effectively
       * a busy wait.
       */
      QTAILQ_FOREACH(bs, &bdrv_states, list) {
          while (qemu_co_enter_next(&bs->throttled_reqs)) {
              busy = true;
          }
      }
  } while (busy);

Note that throttle requests are kicked but I/O throttling limits are
still in effect.  The loop spins until the vm_clock time allows the
request to make progress and complete.

The new throttling code introduced bdrv_start_throttled_reqs().  This
function not only kicks throttled requests but also temporarily disables
throttling so requests can run.

The outdated FIXME comment can be removed.  Also drop the busy = true
assignment since we overwrite it immediately afterwards.

Reviewed-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-06 16:53:51 +01:00
Max Reitz 66f6b8143b block: Close backing file early in bdrv_img_create
Leaving the backing file open although it is not needed anymore can
cause problems if it is opened through a block driver which allows
exclusive access only and if the create function of the block driver
used for the top image (the one being created) tries to close and reopen
the image file (which will include opening the backing file a second
time).

In particular, this will happen with a backing file opened through
qemu-nbd and using qcow2 as the top image file format (which reopens the
image to flush it to disk).

In addition, the BlockDriverState in bdrv_img_create() is used for the
backing file only; it should therefore be made local to the respective
block.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-04 11:29:19 +01:00
Paolo Bonzini b8d71c09f3 block: make bdrv_co_do_write_zeroes stricter in producing aligned requests
Right now, bdrv_co_do_write_zeroes will only try to align the
beginning of the request.  However, it is simpler for many
formats to expect the block layer to separate both the head *and*
the tail.  This makes sure that the format's bdrv_co_write_zeroes
function will be called with aligned sector_num and nb_sectors for
the bulk of the request.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini 7ce21016b6 block: handle ENOTSUP from discard in generic code
Similar to write_zeroes, let the generic code receive a ENOTSUP for
discard operations.  Since bdrv_discard has advisory semantics,
we can just swallow the error.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini d5ef94d43d block: add bdrv_aio_write_zeroes
This will be used by the SCSI layer.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini 94d6ff21f4 block: add flags argument to bdrv_co_write_zeroes tracepoint
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini d20d9b7c67 block: add flags to BlockRequest
This lets bdrv_co_do_rw receive flags, so that it can be used for
zero writes.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:48 +01:00
Paolo Bonzini d51e9fe505 block: generalize BlockLimits handling to cover bdrv_aio_discard too
bdrv_co_discard is only covering drivers which have a .bdrv_co_discard()
implementation, but not those with .bdrv_aio_discard(). Not very nice,
and easy to avoid.

Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:48 +01:00
Kevin Wolf c9fbb99d41 block: Use BDRV_O_NO_BACKING where appropriate
If you open an image temporarily just because you want to check its size
or get it flushed, there's no real reason to open the whole backing file
chain.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2013-11-29 17:41:09 +01:00
Kevin Wolf 9fd3171af9 block: Enable BDRV_O_SNAPSHOT with driver-specific options
In the case of snapshot=on, don't rely on the backing file path in the
temporary image any more, but override the backing file with the given
set of options. This way, block drivers that don't use a file name can
be accessed with snapshot=on, for example:

    -drive file.driver=nbd,file.host=localhost,snapshot=on

Which becomes internally something like:

    file.filename=/tmp/vl.AWQZCu,backing.file.driver=nbd,backing.file.host=localhost

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29 13:40:37 +01:00
Fam Zheng 4cc70e9337 blkdebug: add "remove_break" command
This adds "remove_break" command which is the reverse of blkdebug
command "break": it removes all breakpoints with given tag and resumes
all the requests.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-29 13:40:37 +01:00
Fam Zheng 21b5683508 qapi: Change BlockDirtyInfo to list
We have multiple dirty bitmaps in BDS now, switch QAPI to allow query
it (BlockInfo.dirty_bitmaps), and also drop old BlockInfo.dirty.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29 13:40:36 +01:00
Fam Zheng e4654d2d94 block: per caller dirty bitmap
Previously a BlockDriverState has only one dirty bitmap, so only one
caller (e.g. a block job) can keep track of writing. This changes the
dirty bitmap to a list and creates a BdrvDirtyBitmap for each caller, the
lifecycle is managed with these new functions:

    bdrv_create_dirty_bitmap
    bdrv_release_dirty_bitmap

Where BdrvDirtyBitmap is a linked list wrapper structure of HBitmap.

In place of bdrv_set_dirty_tracking, a BdrvDirtyBitmap pointer argument
is added to these functions, since each caller has its own dirty bitmap:

    bdrv_get_dirty
    bdrv_dirty_iter_init
    bdrv_get_dirty_count

bdrv_set_dirty and bdrv_reset_dirty prototypes are unchanged but will
internally walk the list of all dirty bitmaps and set them one by one.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29 13:40:33 +01:00
Peter Lieven c3d8688470 block/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocks
this patch does 2 things:
a) only do additional call outs if BDRV_BLOCK_ZERO is not already set.
b) use the newly introduced bdrv_unallocated_blocks_are_zero()
   to return the zero state of an unallocated block. the used callout
   to bdrv_has_zero_init() is only valid right after bdrv_create.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:52 +01:00
Peter Lieven d75cbb5e68 block: introduce bdrv_make_zero
this patch adds a call to completely zero out a block device.
the operation is sped up by checking the block status and
only writing zeroes to the device if they currently do not
return zeroes. optionally the zero writing can be sped up
by setting the flag BDRV_REQ_MAY_UNMAP to emulate the zero
write by unmapping if the driver supports it.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:52 +01:00
Peter Lieven 6f14da5247 block: honour BlockLimits in bdrv_co_discard
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:51 +01:00
Peter Lieven c31cb70728 block: honour BlockLimits in bdrv_co_do_write_zeroes
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:51 +01:00
Peter Lieven 4ce786914b block: add wrappers for logical block provisioning information
This adds 2 wrappers to read the unallocated_blocks_are_zero and
can_write_zeroes_with_unmap info from the BDI. The wrappers are
required to check for the existence of a backing_hd and
if the devices are opened with the correct flags.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:51 +01:00
Peter Lieven d32f35cbc5 block: introduce BDRV_REQ_MAY_UNMAP request flag
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:51 +01:00
Peter Lieven aa7bfbfff7 block: add flags to bdrv_*_write_zeroes
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:51 +01:00