They aren't used afterwards nor supposed to be stored by a bdrv_create
handler.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This adds the wr_highest_sector blockstat which implements what is generally
known as the high watermark. It is the highest offset of a sector written to
the respective BlockDriverState since it has been opened.
The query-blockstat QMP command is extended to add this value to the result,
and also to add the statistics of the underlying protocol in a new "parent"
field. Note that to get the "high watermark" of a qcow2 image, you need to look
into the wr_highest_sector field of the parent (which can be a file, a
host_device, ...). The wr_highest_sector of the qcow2 BlockDriverState itself
is the highest offset on the _virtual_ disk that the guest has written to.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The BlockDriver bdrv_getlength function is called from the I/O code path
when checking that the request falls within the device. Unfortunately
this involves an lseek system call in the raw protocol; every read or
write request will incur this lseek cost.
Jan Kiszka <jan.kiszka@siemens.com> identified this issue and its
latency overhead. This patch caches device length in the existing
total_sectors variable so lseek calls can be avoided for fixed size
devices.
Growable devices fall back to the full bdrv_getlength code path because
I have not added logic to detect extending the size of the device in a
write.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
It is safer to set backing_hd to NULL after deleting it so that any use
after deletion is obvious during development. Happy segfaulting!
This patch should be applied after Kevin Wolf's "vmdk: Convert to
bdrv_open" so that vmdk does not segfault on close.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This fixes the problem that qemu-img's use of no_zero_init only considered the
no_zero_init flag of the format driver, but not of the underlying protocols.
Between the raw/file split and this fix, converting to host devices is broken.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Format drivers shouldn't need to bother with things like file names, but rather
just get an open BlockDriverState for the underlying protocol. This patch
introduces this behaviour for bdrv_open implementation. For protocols which
need to access the filename to open their file/device/connection/... a new
callback bdrv_file_open is introduced which doesn't get an underlying file
opened.
For now, also some of the more obscure formats use bdrv_file_open because they
open() the file themselves instead of using the block.c functions. They need to
be fixed in later patches.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
bdrv_open contains quite some code that is only useful for opening images (as
opposed to opening files by a protocol), for example snapshots.
This patch splits the code so that we have bdrv_open_file() for files (uses
protocols), bdrv_open() for images (uses format drivers) and bdrv_open_common()
for the code common for opening both images and files.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We're running into various problems because the "raw" file access, which
is used internally by the various image formats is entangled with the
"raw" image format, which maps the VM view 1:1 to a file system.
This patch renames the raw file backends to the file protocol which
is treated like other protocols (e.g. nbd and http) and adds a new
"raw" image format which is just a wrapper around calls to the underlying
protocol.
The patch is surprisingly simple, besides changing the probing logical
in block.c to only look for image formats when using bdrv_open and
renaming of the old raw protocols to file there's almost nothing in there.
For creating images, a new bdrv_create_file is introduced which guesses the
protocol to use. This allows using qemu-img create -f raw (or just using the
default) for both files and host devices. Converting the other format drivers
to use this function to create their images is left for later patches.
The only issues still open are in the handling of the host devices.
Firstly in current qemu we can specifiy the host* format names
on various command line acceping images, but the new code can't
do that without adding some translation. Second the layering breaks
the no_zero_init flag in the BlockDriver used by qemu-img. I'm not
happy how this is done per-driver instead of per-state so I'll
prepare a separate patch to clean this up.
There's some more cleanup opportunity after this patch, e.g. using
separate lists and registration functions for image formats vs
protocols and maybe even host drivers, but this can be done at a
later stage.
Also there's a check for protocol in bdrv_open for the BDRV_O_SNAPSHOT
case that I don't quite understand, but which I fear won't work as
expected - possibly even before this patch.
Note that this patch requires various recent block patches from Kevin
and me, which should all be in his block queue.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
A new iovec array is allocated when creating a merged write request.
This patch ensures that the iovec array is deleted in addition to its
qiov owner.
Reported-by: Leszek Urbanski <tygrys@moo.pl>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The bdrv_first linked list of BlockDriverStates is currently extern so
that block migration can iterate the list. However, since there is
already a bdrv_iterate() function there is no need to expose bdrv_first.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
BDRV_O_FILE is only used to communicate between bdrv_file_open and bdrv_open.
It affects two things: first bdrv_open only searches for protocols using
find_protocol instead of all image formats and host drivers. We can easily
move that to the caller and pass the found driver to bdrv_open. Second
it is used to not force a read-write open of a snapshot file. But we never
use bdrv_file_open to open snapshots and this behaviour doesn't make sense
to start with.
qemu-io abused the BDRV_O_FILE for it's growable option, switch it to
using bdrv_file_open to make sure we only open files as growable were
we can actually support that.
This patch requires Kevin's "[PATCH] Replace calls of old bdrv_open" to
be applied first.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
What is known today as bdrv_open2 becomes the new bdrv_open. All remaining
callers of the old function are converted to the new one. In some places they
even know the right format, so they should have used bdrv_open2 from the
beginning.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Block drivers can trigger a blkdebug event whenever they reach a place where it
could be useful to inject an error for testing/debugging purposes.
Rules are read from a blkdebug config file and describe which action is taken
when an event is triggered. For now this is only injecting an error (with a few
options) or changing the state (which is an integer). Rules can be declared to
be active only in a specific state; this way later rules can distiguish on
which path we came to trigger their event.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Previously multiwrite_user_cb was never called if a request in the multiwrite
batch failed right away because it did set mcb->error immediately. Make it look
more like a normal callback to fix this.
Reported-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
When two requests of the same multiwrite batch fail, the callback of all
requests in that batch were called twice. This could have any kind of nasty
effects, in my case it lead to use after free and eventually a segfault.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Open backing file read-only where possible
Upgrade backing file to read-write during commit, back to read-only after commit
If upgrade fail, back to read-only. If also fail, "disconnect" the drive.
Signed-off-by: Naphtali Sprei <nsprei@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
It's not needed to check the return of qobject_from_jsonf()
anymore, as an assert() has been added there.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Clean up the current mess about figuring out which flags to pass to the
driver. BDRV_O_FILE, BDRV_O_SNAPSHOT and BDRV_O_NO_BACKING are flags
only used by the block layer internally so filter them out directly.
Previously BDRV_O_NO_BACKING could accidentally be passed to the drivers,
but wasn't ever used.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit introduces the bdrv_mon_event() function, which
should be called by block subsystems (eg. IDE) when a I/O
error occurs, so that an QMP event is emitted.
The following information is currently provided in the event:
- device name
- operation (ie. "read" or "write")
- action taken (eg. "stop")
Event example:
{ "event": "BLOCK_IO_ERROR",
"data": { "device": "ide0-hd1",
"operation": "write",
"action": "stop" },
"timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This will manage dirty counter for each device and will allow to get the
dirty counter from above.
Signed-off-by: Liran Schour <lirans@il.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
If we go over the maximum number of iovecs support by syscall we get
back EINVAL from the kernel which translate to I/O errors for the guest.
Add a MAX_IOV defintion for platforms that don't have it. For now we use
the same 1024 define that's used on Linux and various other platforms,
but until the windows block backend implements some kind of vectored I/O
it doesn't matter.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Win32 suffers from a very big memory leak when dealing with SCSI devices.
Each read/write request allocates memory with qemu_memalign (ie
VirtualAlloc) but frees it with qemu_free (ie free).
Pair all qemu_memalign() calls with qemu_vfree() to prevent such leaks.
Signed-off-by: Herve Poussineau <hpoussin@reactos.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Check the whitelist as early as possible instead of continuing the
setup, and move all the error handling code to the end of the
function.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
If we go over the maximum number of iovecs support by syscall we get
back EINVAL from the kernel which translate to I/O errors for the guest.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Instead of using the field 'readonly' of the BlockDriverState struct for passing the request,
pass the request in the flags parameter to the function.
Signed-off-by: Naphtali Sprei <nsprei@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The backing device is only modified from bdrv_commit. So instead of
flushing it every time bdrv_flush is called for the front-end device
only flush it after we're written data to it in bdrv_commit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Introduce the functions needed to change the backing file of an image. The
function is implemented for qcow2.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
If an image references a backing file that doesn't exist, qemu-img info fails
to open this image. Exactly in this case the info would be valuable, though:
the user might want to find out which file is missing.
This patch introduces a BDRV_O_NO_BACKING flag to ignore the backing file when
opening the image. qemu-img info is the first user and provides info now even
if the backing file is invalid.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
CC block.o
cc1: warnings being treated as errors
block.c: In function 'bdrv_open2':
block.c:400: error: ignoring return value of 'realpath', declared with attribute warn_unused_result
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Each device statistic information is stored in a QDict and
the returned QObject is a QList of all devices.
This commit should not change user output.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Each block device information is stored in a QDict and the
returned QObject is a QList of all devices.
This commit should not change user output.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This switches the dirty bitmap to a true bitmap, reducing its footprint
(specifically in caches). It moreover fixes off-by-one bugs in
set_dirty_bitmap (nb_sectors+1 were marked) and bdrv_get_dirty (limit
check allowed one sector behind end of drive). And is drops redundant
dirty_tracking field from BlockDriverState.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Instead of duplicating the definition of constants or introducing
trivial retrieval functions move the SECTOR constants into the public
block API. This also obsoletes sector_per_block in BlkMigState.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
To support live migration without shared storage we need to be able to trace
writes to disk while migrating. This Patch expose dirty block tracking per
device to be polled from upper layer.
Changes from v4:
- Register dirty tracking for each block device.
- Minor coding style issues.
- Block.c will now manage a dirty bitmap per device once
bdrv_set_dirty_tracking() is called. Bitmap is polled by the upper
layer (block-migration.c).
Signed-off-by: Liran Schour <lirans@il.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
We have code for a quite a few block formats. While I trust that all
of these formats are useful at least for some people in some
circumstances, some of them are of a kind that friends don't let
friends use in production.
This patch provides an optional block format whitelist, default off.
If a whitelist is configured with --block-drv-whitelist, QEMU proper
can use only whitelisted formats. Other programs, like qemu-img, are
not affected.
Drivers for formats off the whitelist still participate in format
probing, to ensure all programs probe exactly the same. Without that,
QEMU proper would be prone to treat images with a format off the
whitelist as raw when the image's format is probed.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This is a slightly revised patch for adding readonly flag to the -drive command.
Even though this patch is "stand-alone", it assumes a previous related patch (in Anthony staging tree), that passes
the readonly attribute of the drive to the guest OS, applied first.
This enables sharing same image between guests, with readonly access.
Implementaion mark the drive as read_only and changes the flags when actually opening the file.
The readonly attribute of a qcow also passed to it's base file.
For ide that cannot pass the readonly attribute to the guest OS, disallow the readonly flag.
Also, return error code from bdrv_truncate for readonly drive.
Signed-off-by: Naphtali Sprei <nsprei@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
bdrv_read/write emulation is used as the perfect example why we need something
like AsyncContexts. So maybe they better start using it.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Problem: Our file sys-queue.h is a copy of the BSD file, but there are
some additions and it's not entirely compatible. Because of that, there have
been conflicts with system headers on BSD systems. Some hacks have been
introduced in the commits 15cc923584,
f40d753718,
96555a96d7 and
3990d09adf but the fixes were fragile.
Solution: Avoid the conflict entirely by renaming the functions and the
file. Revert the previous hacks.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Instead stalling the VCPU while serving a cache flush try to do it
asynchronously. Use our good old helper thread pool to issue an
asynchronous fdatasync for raw-posix. Note that while Linux AIO
implements a fdatasync operation it is not useful for us because
it isn't actually implement in asynchronous fashion.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
