bdrv_close should leave fields in the same state as bdrv_new.  It is
not up to bdrv_open_common to fix the mess.

Also, backing_format was not being re-initialized.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

path_has_protocol will erroneously return "true" if the colon is part
of a filename.  These names are common with stable device names produced
by udev.  We cannot fully protect against this in case the filename
does not have a path component (e.g. if the current directory is
/dev/disk/by-path), but in the common case there will be a slash before
and path_has_protocol can easily detect that and return false.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

On Windows, all the logic is already in is_windows_drive and
is_windows_drive_prefix.  On POSIX, there is no need to look
out for colons.

The win32 code changes the behaviour in some cases, we could have
something like "d:foo.img". The old code would treat it as relative
path, the new one as absolute. Now the path is absolute, because to
go from c:/program files/blah to d:foo.img you cannot say c:/program
files/blah/d:foo.img.  You have to say d:foo.img.  But you could also
say it's relative because (I think, at least it was like that in DOS
15 years ago) d:foo.img is relative to the current path of drive D.
Considering how path_is_absolute is used by path_combine, I think it's
better to treat it as absolute.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The limitation on not having I/O after cancellation cannot really be
kept.  Even streaming has a very small race window where you could
cancel a job and have it report completion.  If this window is hit,
bdrv_change_backing_file() will yield and possibly cause accesses to
dangling pointers etc.

So, let's just assume that we cannot know exactly what will happen
after the coroutine has set busy to false.  We can set a very lax
condition:

- if we cancel the job, the coroutine won't set it to false again
(and hence will not call co_sleep_ns again).

- block_job_cancel_sync will wait for the coroutine to exit, which
pretty much ensures no race.

Instead, we track the coroutine that executes the job and put very
strict conditions on what to do while it is quiescent (busy = false).
First of all, the coroutine must never set busy = false while the job
has been cancelled.  Second, the coroutine can be reentered arbitrarily
while it is quiescent, so you cannot really do anything but co_sleep_ns at
that time.  This condition is obeyed by the block_job_sleep_ns function.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This function abstracts the pretty complex semantics of the "busy"
member of BlockJob.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

We are reusing bs->file across close/open, which may not cause any
known bugs but is a recipe for trouble.  Prefer bdrv_delete, and
enjoy the new invariant in the implementation of bdrv_delete.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This is another bug caused by not doing a full cleanup of the BDS
across close/open.  This was found with mirroring by Shaolong Hu,
but it can probably be reproduced also with eject or change.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

bdrv_append must also copy open_flags to the top, because the snapshot
has BDRV_O_NO_BACKING set.  This causes interesting results if you
later use drive-reopen (not upstream) to reopen the image, and lose
the backing file in the process.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

QED's opaque data includes a pointer back to the BlockDriverState.
This breaks when bdrv_append shuffles data between bs_new and bs_top.
To avoid this, add a "rebind" function that tells the driver about
the new relationship between the BlockDriverState and its opaque.

The patch also adds rebind to VVFAT for completeness, even though
it is not used with live snapshots.
Reviewed-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Also reuse elsewhere the new constant for sizeof(unsigned long) * 8.

The dirty bitmap is allocated in bits but declared as unsigned long.
Thus, its memory block is accessed beyond its end unless the image
is a multiple of 64 chunks (i.e. a multiple of 64 MB).
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

bdrv_img_create will temporarily open the backing file to probe its size.
However, this could be done with a read-write open if the wrong flags are
passed to bdrv_img_create.  Since there is really no documentation on
what flags can be passed, assume that bdrv_img_create receives the flags
with which the new image will be opened; sanitize them when opening
the backing file.
Reported-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

These are needed to print "info block" output correctly.  QCOW2 does this
because it needs it to write the header, but QED does not, and common code
is the right place to do it.
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This check applies to all drivers, but QED lacks it.
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NZhi Yong Wu <wuzhy@linux.vnet.ibm.com>
[ Iterate until all block devices have processed all requests,
  add comments. - Paolo ]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The current qemu.git introduces failure with preallocation and some
sizes:

qemu-img create -f qcow2 new.img 976563K -o preallocation=metadata
qemu-img: qemu-coroutine-lock.c:111: qemu_co_mutex_unlock: Assertion
`mutex->locked == 1' failed.

And lock needs to work in coroutine context. So to fix this issue, we
need to make bdrv_create adopt coroutine at first.
Signed-off-by: NZhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Allow streaming operations to be started with an initial speed limit.
This eliminates the window of time between starting streaming and
issuing block-job-set-speed.  Users should use the new optional 'speed'
parameter instead so that speed limits are in effect immediately when
the job starts.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Acked-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Acked-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

There are at least two different errors that can occur in
block_job_set_speed(): the job might not support setting speeds or the
value might be invalid.

Use the Error mechanism to report the error where it occurs.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Acked-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

The block job API uses -errno return values internally and we convert
these to Error in the QMP functions.  This is ugly because the Error
should be created at the point where we still have all the relevant
information.  More importantly, it is hard to add new error cases to
this case since we quickly run out of -errno values without losing
information.

Go ahead and use Error directly and don't convert later.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Acked-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

Signed-off-by: NKevin 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: NLiu Yuan <tailai.ly@taobao.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

If an AIO request is in flight that refers to a BlockDriverState that
has been closed and possibly even freed, more or less anything could
happen. I have seen segfaults, -EBADF return values and qcow2 sometimes
actually catches the situation in bdrv_close() and abort()s.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>

This function will clear all BDRV_O_INCOMING flags.
Signed-off-by: NBenoit Canet <benoit.canet@gmail.com>
Reviewed-by: NStefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

A few fixups for bdrv_append():

The new bs (bs_new) passed into bdrv_append() should be anonymous.  Rather
than call bdrv_make_anon() to enforce this, use an assert to catch when a caller
is passing in a bs_new that is not anonymous.

Also, the new top layer should have its backing_format reflect the original
top's format.

And last, after the swap of bs contents, the device_name will have been copied
down. This needs to be cleared to reflect the anonymity of the bs that was
pushed down.
Signed-off-by: NJeff Cody <jcody@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

There is no need to do this in every implementation of set_speed
(even though there is only one right now).
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Streaming can issue I/O while qcow2_close is running.  This causes the
L2 caches to become very confused or, alternatively, could cause a
segfault when the streaming coroutine is reentered after closing its
block device.  The fix is to cancel streaming jobs when closing their
underlying device.

The cancellation must be synchronous, on the other hand qemu_aio_wait
will not restart a coroutine that is sleeping in co_sleep.  So add
a flag saying whether streaming has in-flight I/O.  If the busy flag
is false, the coroutine is quiescent and, when cancelled, will not
issue any new I/O.

This protects streaming against closing, but not against deleting.
We have a reference count protecting us against concurrent deletion,
but I still added an assertion to ensure nothing bad happens.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NZhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Reviewed-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

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

Monitor operations that manipulate image files must not execute while a
background job (like image streaming) is in progress.  This prevents
corruptions from happening when two pieces of code are manipulating the
image file without knowledge of each other.

The monitor "commit" command raises QERR_DEVICE_IN_USE when
bdrv_commit() returns -EBUSY but "commit all" has no error handling.
This is easy to fix, although note that we do not deliver a detailed
error about which device was busy in the "commit all" case.
Suggested-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This is a QAPI/QMP only command to take a snapshot of a group of
devices. This is similar to the blockdev-snapshot-sync command, except
blockdev-group-snapshot-sync accepts a list devices, filenames, and
formats.

It is attempted to keep the snapshot of the group atomic; if the
creation or open of any of the new snapshots fails, then all of
the new snapshots are abandoned, and the name of the snapshot image
that failed is returned.  The failure case should not interrupt
any operations.

Rather than use bdrv_close() along with a subsequent bdrv_open() to
perform the pivot, the original image is never closed and the new
image is placed 'in front' of the original image via manipulation
of the BlockDriverState fields.  Thus, once the new snapshot image
has been successfully created, there are no more failure points
before pivoting to the new snapshot.

This allows the group of disks to remain consistent with each other,
even across snapshot failures.
Signed-off-by: NJeff Cody <jcody@redhat.com>
Acked-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

These were never used.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Floppies must be read at a specific transfer rate, depending of its own format.
Update floppy description table to include required transfer rate.
Signed-off-by: NHervé Poussineau <hpoussin@reactos.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

It's emitted whenever the tray is moved by the guest or by HMP/QMP
commands.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Acked-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Acked-by: NKevin Wolf <kwolf@redhat.com>

They are QMP events, not monitor events. Rename them accordingly.

Also, move bdrv_emit_qmp_error_event() up in the file. A new event will
be added soon and it's good to have them next each other.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Acked-by: NKevin Wolf <kwolf@redhat.com>

Copy-on-Read populates the image file with data read from a backing
image.  In order to avoid bloating the image file when all zeroes are
read we should scan the buffer and perform an optimized zero write
operation.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The ability to zero regions of an image file is a useful primitive for
higher-level features such as image streaming or zero write detection.

Image formats may support an optimized metadata representation instead
of writing zeroes into the image file.  This allows zero writes to be
potentially faster than regular write operations and also preserve
sparseness of the image file.

The .bdrv_co_write_zeroes() interface should be implemented by block
drivers that wish to provide efficient zeroing.

Note that this operation is different from the discard operation, which
may leave the contents of the region indeterminate.  That means
discarded blocks are not guaranteed to contain zeroes and may contain
junk data instead.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Add bdrv_find_backing_image: given a BlockDriverState pointer, and an id,
traverse the backing image chain to locate the id.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Previously copy-on-read could only be enabled for all requests to a
block device.  This means requests coming from the guest as well as
QEMU's internal requests would perform copy-on-read when enabled.

For image streaming we want to support finer-grained behavior than just
populating the image file from its backing image.  Image streaming
supports partial streaming where a common backing image is preserved.
In this case guest requests should not perform copy-on-read because they
would indiscriminately copy data which should be left in a backing image
from the backing chain.

Introduce a per-request flag for copy-on-read so that a block device can
process both regular and copy-on-read requests.  Overlapping reads and
writes still need to be serialized for correctness when copy-on-read is
happening, so add an in-flight reference count to track this.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>