count_cow_clusters() tries to reuse existing functions, and all it
achieves is to make things much more complicated than they really are:
Everything needs COW, unless it's a normal cluster with refcount 1.
This patch implements the obvious way of doing this, and by using
qcow2_get_cluster_type() it gets rid of all flag magic.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Zero clusters will add another cluster type. Refactor the open-coded
cluster type detection into a switch of QCOW2_CLUSTER_* options so that
the detection is in a single place. This makes it easier to add new
cluster types.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This changes the still existing places that assume that the only flags
are QCOW_OFLAG_COPIED and QCOW_OFLAG_COMPRESSED to properly mask out
reserved bits.
It does not convert bdrv_check yet.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2_alloc_compressed_cluster_offset() already fails if the copied flag
is set, because qcow2_write_compressed() doesn't perform COW as it would
have to do to allow this.
However, what we really want to check here is whether the cluster is
allocated or not. With internal snapshots the copied flag may not be set
on allocated clusters. Check the cluster offset instead.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Until now, count_contiguous_clusters() has an argument that allowed to
specify flags that should be ignored in the comparison, i.e. that are
allowed to change between contiguous clusters.
This patch changes the function so that it ignores all flags by default
now and you need to pass the flags on which it should stop.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
With this change, reading from a qcow2 image ignores all reserved bits
that are set in an L1 or L2 table entry.
Now get_cluster_offset() assigns *cluster_offset only the offset without
any other flags. The cluster type is not longer encoded in the offset,
but a positive return value in case of success.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This allows that different snapshots of an image can have different
sizes, which is a requirement for enabling image resizing even with
images that have internal snapshots.
We don't do the actual support for it now, but make sure that the
additional field is present and not completely ignored in all version 3
images. When trying to load a snapshot of different size, it returns
an error.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This updates the qcow2 specification to cover version 3. It contains the
following changes:
- Added compatible/incompatible/auto-clear feature bits plus an optional
feature name table to allow useful error messages even if an older
version doesn't know some feature at all.
- Configurable refcount width. If you don't want to use internal
snapshots, make refcounts one bit and save cache space and I/O.
- Zero cluster flags. This allows discard even with a backing file that
doesn't contain zeros. It is also useful for copy-on-read/image
streaming, as you'll want to keep sparseness without accessing the
remote image for an unallocated cluster all the time.
- Fixed internal snapshot metadata to use 64 bit VM state size. You
can't save a snapshot of a VM with >= 4 GB RAM today.
- Extended internal snapshot metadata to contain the disk size, so that
resizing images that have snapshots can be allowed in the future.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Refcount block allocation and refcount table growth rely on
s->free_cluster_index pointing to somewhere after the current
allocation. Change qcow2_alloc_cluster_at() to fulfill this
assumption.
Without this change it could happen that a newly allocated refcount
block and the allocated data block point to the same area in the image
file, causing data corruption in the long run.
This fixes a bug that became first visible after commit 250196f1.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The new autotests in tests/ generate a number of files, both
executable and source, which are not caught by the existing .gitignore
files. This patch adds a new .gitignore in tests/ which covers these.
[Changed 'rtc-test' to '*-test' so future tests do not need to be added
to .gitignore on a case-by-case basis. Stefan]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
This was reported by https://bugs.launchpad.net/qemu/+bug/984476.
I also changed the case for 'error'.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Eric Bénard <eric@eukrea.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
val is an uint64_t, therefore %d was not correct.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
It is invalid to return a value from a function
returning void.
[C99 6.8.6.4 says "A return statement with an expression shall not
appear in a function whose return type is void" but gcc 4.6.3 with QEMU
compile flags does not complain. It's still worth fixing this. Stefan]
Signed-off-by: Amos Kong <akong@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
`hostname -s` may output an errror:
hostname: Name or service not known
This causes all tests to fail for `make check-block`.
Suppress such error messages, letting the tests succeed.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The 'qemu-img convert -h' advertise that the default cache mode is
'writeback', while in fact it is 'unsafe'.
This patch 1) fix the help manual and 2) let bdrv_close() call bdrv_flush()
2) is needed because some backend storage doesn't have a self-flush
mechanism(for e.g., sheepdog), so we need to call bdrv_flush() to make
sure the image is really writen to the storage instead of hanging around
writeback cache forever.
Signed-off-by: Liu Yuan <tailai.ly@taobao.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
When linux-specific commands (including guest-fsfreeze-*) were consolidated
under defined(__linux__), we forgot to account for the case where
defined(__linux__) && !defined(FIFREEZE). As a result stubs are no longer
being generated on linux hosts that don't have FIFREEZE support. Fix
this.
Tested-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
The do...while loop can never loop, because select will just not return
0 when invoked with infinite timeout.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The definition of when qemu_aio_flush should loop is much simpler
than it looks. It just has to call qemu_aio_wait until it makes
no progress and all flush callbacks return false. qemu_aio_wait
is the logical place to tell the caller about this.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Right now, nbd_wr_sync will hang if no data at all is available on the
socket and the other side is not going to provide any. Relax this by
making it loop only for writes or partial reads. This fixes a race
where one thread is executing qemu_aio_wait() and another is executing
main_loop_wait(). Then, the select() call in main_loop_wait() can return
stale data and call the "readable" callback with no data in the socket.
Reported-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In the next patch we need to look at the return code of nbd_wr_sync.
To avoid percolating the socket_error() ugliness all around, let's
handle errors by returning negative errno values.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
GCC (pedantically, but correctly) considers that a negative ssize_t may
become positive when casted to int. This may cause uninitialized variable
warnings when a function returns such a negative ssize_t and is inlined.
Propagate ssize_t return types to avoid this.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
posix_aio_read already calls qemu_aio_process_queue, and dually
qemu_aio_process_queue is always followed by a select loop that calls
posix_aio_read.
No races are possible, so there is no need for a separate process_queue
callback.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
QED uses vm_clock timers so that images are not touched during and after
migration. This however does not apply to qemu-io and qemu-img.
Treat vm_clock as a synonym for rt_clock there, and enable it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This will let timers run during aio_read and aio_write commands,
though not during synchronous commands.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
[Actually, we should report it only if discard_granularity is nonzero.
Older SBC drafts assigned 0 to thin provisioning and 1 to thick
(resource-provisioned, they call it). Newer drafts assign respectively
1 and 2 - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This was added in SBC r26 in place of the reserved bits that were
present up to that version.
It is the same as WRITE_SAME_16 as far as QEMU is concerned.
Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In the next patch we want to reenter the coroutine from
block_job_cancel_sync and cancel the timer.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Someone forgot something in commit 29c1a730... Documenting the right
return value is not enough, you also need to actually return it in the
code.
This bug sometimes causes error return values even when everything has
succeeded: The new offset of the refcount block is truncated to 32 bits
and interpreted as signed. At least with small cluster sizes it's easy
to get a negative return value this way.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
If do_alloc_cluster_offset() fails, the error handling code tried to
remove the request from the in-flight queue, to which it wasn't added
yet, resulting in a NULL pointer dereference.
m->nb_clusters really only becomes != 0 when the request is in the list.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The IDE PIO write sector code path uses bdrv_write() and hence can make
the guest unresponsive while the I/O request is in progress. This patch
converts ide_sector_write() to use bdrv_aio_writev() by using the
BUSY_STAT bit to tell the guest that the request is in progress.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Tested-by: Richard Davies <richard@arachsys.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The IDE PIO interface currently uses bdrv_read() to perform reads
synchronously. Synchronous I/O in the vcpu thread is bad because it
prevents the guest from executing code - it makes the guest
unresponsive.
This patch converts IDE PIO to use bdrv_aio_readv(). We simply need to
use the BUSY_STAT status so the guest knows to wait while we are busy.
The only external user of ide_sector_read() is restart behavior on I/O
errors and it is not affected by this change. We still need to restart
I/O in the same way.
Migration is also unaffected if I understand the code correctly. We
continue to use the same transfer function and the BUSY_STAT status
should never be migrated since we flush I/O before migrating device
state.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Tested-by: Richard Davies <richard@arachsys.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
