BlockDriverState member buffer_alignment is initially 512. The device
model may set them, with bdrv_set_buffer_alignment(). If the device
model gets detached (hot unplug), the device's alignment is left
behind. Only okay because device hot unplug automatically destroys
the BlockDriverState. But that's a questionable feature, best not to
rely on it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Device models should be able to set it without an unclean include of
block_int.h.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Need to ask the device, so this requires new BlockDevOps member
is_tray_open().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
It's a confused mess (see previous commit). No users remain.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
BlockDriverState member removable is a confused mess. It is true when
an ide-cd, scsi-cd or floppy qdev is attached, or when the
BlockDriverState was created with -drive if={floppy,sd} or -drive
if={ide,scsi,xen,none},media=cdrom ("created removable"), except when
an ide-hd, scsi-hd, scsi-generic or virtio-blk qdev is attached.
Three users remain:
1. eject_device(), via bdrv_is_removable() uses it to determine
whether a block device can eject media.
2. bdrv_info() is monitor command "info block". QMP documentation
says "true if the device is removable, false otherwise". From the
monitor user's point of view, the only sensible interpretation of
"is removable" is "can eject media with monitor commands eject and
change".
A block device can eject media unless a device is attached that
doesn't support it. Switch the two users over to new
bdrv_dev_has_removable_media() that returns exactly that.
3. bdrv_getlength() uses to suppress its length cache when media can
change (see commit 46a4e4e6). Media change is either monitor
command change (updates the length cache), monitor command eject
(doesn't update the length cache, easily fixable), or physical
media change (invalidates length cache, not so easily fixable).
I'm refraining from improving anything here, because this series is
long enough already. Instead, I simply switch it over to
bdrv_dev_has_removable_media() as well.
This changes the behavior of the length cache and of monitor commands
eject and change in two cases:
a. drive not created removable, no device attached
The commit makes the drive removable, and defeats the length cache.
Example: -drive if=none
b. drive created removable, but the attached drive is non-removable,
and doesn't call bdrv_set_removable(..., 0) (most devices don't)
The commit makes the drive non-removable, and enables the length
cache.
Example: -drive if=xen,media=cdrom -M xenpv
The other non-removable devices that don't call
bdrv_set_removable() can't currently use a drive created removable,
either because they aren't qdevified, or because they lack a drive
property. Won't stay that way.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Requires new BlockDevOps member is_medium_locked(). Implement for IDE
and SCSI CD-ROMs.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The device model knows best when to accept the guest's eject command.
No need to detour through the block layer.
bdrv_eject() can't fail anymore. Make it void.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Commit 4be9762a changed bdrv_is_inserted() to fail when the tray is
open. Unfortunately, there are two different kinds of users, with
conflicting needs.
1. Device models using bdrv_eject(), currently ide-cd and scsi-cd.
They expect bdrv_is_inserted() to reflect the tray status. Commit
4be9762a makes them happy.
2. Code that wants to know whether a BlockDriverState has media, such
as find_image_format(), bdrv_flush_all(). Commit 4be9762a makes them
unhappy. In particular, it breaks flush on VM stop for media ejected
by the guest.
Revert the change to bdrv_is_inserted(). Check the tray status in the
device models instead.
Note on IDE: Since only ATAPI devices have a tray, and they don't
accept ATA commands since the recent commit "ide: Reject ATA commands
specific to drive kinds", checking in atapi.c suffices.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
savevm and loadvm silently ignore block devices with removable media,
such as floppies and SD cards. Rolling back a VM to a previous
checkpoint will *not* roll back writes to block devices with removable
media.
Moreover, bdrv_is_removable() is a confused mess, and wrong in at
least one case: it considers "-drive if=xen,media=cdrom -M xenpv"
removable. It'll be cleaned up later in this series.
Read-only block devices are also ignored, but that's okay.
Fix by ignoring only read-only block devices and empty block devices.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Change (!bdrv_is_removable(bs) || bdrv_is_inserted(bs)) to just
bdrv_is_inserted(). Rationale:
The value of bdrv_is_removable(bs) matters only when
bdrv_is_inserted(bs) is false.
bdrv_is_inserted(bs) is true when bs is open (bs->drv != NULL) and
not an empty host drive (CD-ROM or floppy).
Therefore, bdrv_is_removable(bs) matters only when:
1. bs is not open
old: may call bdrv_flush(bs), which does nothing
new: won't call
2. bs is an empty host drive
old: may call bdrv_flush(bs), which calls driver method
raw_flush(), which calls fdatasync() or equivalent, which
can't do anything useful while the drive is empty
new: won't call
Result is bs->drv && !bdrv_is_read_only(bs) && bdrv_is_inserted(bs).
bdrv_is_inserted(bs) implies bs->drv. Drop the redundant test.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Multiplexing callbacks complicates matters needlessly.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
For now, this just protects against programming errors like having the
same drive back multiple non-qdev devices, or untimely bdrv_delete().
Later commits will add other interesting uses.
While there, rename BlockDriverState member peer to dev, bdrv_attach()
to bdrv_attach_dev(), bdrv_detach() to bdrv_detach_dev(), and
bdrv_get_attached() to bdrv_get_attached_dev().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Most changes were made using these commands:
git grep -la '__attribute__((packed))'|xargs perl -pi -e 's/__attribute__\(\(packed\)\)/QEMU_PACKED/'
git grep -la '__attribute__ ((packed))'|xargs perl -pi -e 's/__attribute__ \(\(packed\)\)/QEMU_PACKED/'
git grep -la '__attribute__((__packed__))'|xargs perl -pi -e 's/__attribute__\(\(__packed__\)\)/QEMU_PACKED/'
git grep -la '__attribute__ ((__packed__))'|xargs perl -pi -e 's/__attribute__ \(\(__packed__\)\)/QEMU_PACKED/'
git grep -la '__attribute((packed))'|xargs perl -pi -e 's/__attribute\(\(packed\)\)/QEMU_PACKED/'
Whitespace in linux-user/syscall_defs.h was fixed manually
to avoid warnings from scripts/checkpatch.pl.
Manual changes were also applied to hw/pc.c.
I did not fix indentation with tabs in block/vvfat.c.
The patch will show 4 errors with scripts/checkpatch.pl.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Account the total latency for read/write/flush requests. This allows
management tools to average it based on a snapshot of the nr ops
counters and allow checking for SLAs or provide statistics.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Decouple the I/O accounting from bdrv_aio_readv/writev/flush and
make the hardware models call directly into the accounting helpers.
This means:
- we do not count internal requests from image formats in addition
to guest originating I/O
- we do not double count I/O ops if the device model handles it
chunk wise
- we only account I/O once it actuall is done
- can extent I/O accounting to synchronous or coroutine I/O easily
- implement I/O latency tracking easily (see the next patch)
I've conveted the existing device model callers to the new model,
device models that are using synchronous I/O and weren't accounted
before haven't been updated yet. Also scsi hasn't been converted
to the end-to-end accounting as I want to defer that after the pending
scsi layer overhaul.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch adds -drive cache=directsync for O_DIRECT | O_SYNC host file
I/O with no disk write cache presented to the guest.
This mode is useful when guests may not be sending flushes when
appropriate and therefore leave data at risk in case of power failure.
When cache=directsync is used, write operations are only completed to
the guest when data is safely on disk.
This new mode is like cache=writethrough but it bypasses the host page
cache.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch introduces bdrv_parse_cache_flags() which sets open flags
given a cache mode. Previously this was duplicated in blockdev.c and
qemu-img.c.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Fix code format to make checkpatch.pl happy.
Signed-off-by: Robert Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
If we're already in a coroutine, there is no reason to use the synchronous
version of block layer functions when a coroutine one exists. This makes
bdrv_read/write/flush use bdrv_co_* when used inside a coroutine.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The purpose of AsyncContexts was to protect qcow and qcow2 against reentrancy
during an emulated bdrv_read/write (which includes a qemu_aio_wait() call and
can run AIO callbacks of different requests if it weren't for AsyncContexts).
Now both qcow and qcow2 are protected by CoMutexes and AsyncContexts can be
removed.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In order to be able to call bdrv_co_readv/writev for drivers that don't
implement the functions natively, add an emulation that uses the AIO functions
to implement them.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Use the bdrv_co_readv/writev callbacks to implement bdrv_aio_readv/writev and
bdrv_read/write if a driver provides the coroutine version instead of the
synchronous or AIO version.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add new block driver callbacks bdrv_co_readv/writev, which work on a
QEMUIOVector like bdrv_aio_*, but don't need a callback. The function may only
be called inside a coroutine, so a block driver implementing this interface can
yield instead of blocking during I/O.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Commit aea2a33c made bdrv_eject() obey the locked flag. Correct for
medium eject (eject_flag set), incorrect for medium load (eject_flag
clear). See MMC-5 Table 341 "Actions for Lock/Unlock/Eject".
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Callees always return 0, except for FreeBSD's cdrom_eject(), which
returns -ENOTSUP when the device is in a terminally wedged state.
The only caller is bdrv_eject(), and it maps -ENOTSUP to 0 since
commit 4be9762a.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
BlockDriverState members change_cb and change_opaque are initially
null. The device model may set them, with bdrv_set_change_cb(). If
the device model gets detached (hot unplug), they're left dangling.
Only safe because device hot unplug automatically destroys the
BlockDriverState. But that's a questionable feature, best not to rely
on it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qemu-img.c wants to count allocated file size of image. Previously it
counts a single bs->file by 'stat' or Window API. As VMDK introduces
multiple file support, the operation becomes format specific with
platform specific meanwhile.
The functions are moved to block/raw-{posix,win32}.c and qemu-img.c calls
bdrv_get_allocated_file_size to count the bs. And also added VMDK code
to count his own extents.
Signed-off-by: Fam Zheng <famcool@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Block drivers that don't support creating images don't have a size option. Fail
gracefully instead of segfaulting when trying to access the option's value.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Change BDRV_O_NOCACHE to only imply bypassing the host OS file cache,
but no writeback semantics. All existing callers are changed to also
specify BDRV_O_CACHE_WB to give them writeback semantics.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
No users of bdrv_get_type_hint() left. bdrv_set_type_hint() can make
the media removable by side effect. Make that explicit.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
query-block's specification documents response member "type" with
values "hd", "cdrom", "floppy", "unknown".
Its value is unreliable: a block device used as floppy has type
"floppy" if created with if=floppy, but type "hd" if created with
if=none.
That's because with if=none, the type is at best a declaration of
intent: the drive can be connected to any guest device. Its type is
really the guest device's business. Reporting it here is wrong.
No known user of QMP uses "type". It's unlikely that any unknown
users exist, because its value is useless unless you know how the
block device was created. But then you also know the true value.
Fixing the broken value risks breaking (hypothetical!) clients that
somehow rely on the current behavior. Not fixing the value risks
breaking (hypothetical!) clients that rely on the value to be
accurate. Can't entirely avoid hypothetical lossage. Change the
value to be always "unknown".
This makes "info block" always report "type=unknown". Pointless.
Change it to not report the type.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The code changed here is an unused data type name (evt_flush_occurred).
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
The block layer caches the device size to avoid doing lseek(fd, 0,
SEEK_END) every time this value is needed. For removable media the
device size becomes stale if a new medium is inserted. This patch
simply prevents device size caching for removable media.
A smarter solution is to update the cached device size when a new medium
is inserted. Given that there are currently bugs with CD-ROM media
change I do not want to implement that approach until we've gotten
things correct first.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
It can be handy to know when the guest locks/unlocks the CD-ROM tray.
This trace event makes that possible.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
When removing a drive from the host-side via drive_del we currently have
the following path:
drive_del
qemu_aio_flush()
bdrv_close() // zaps bs->drv, which makes any subsequent I/O get
// dropped. Works as designed
drive_uninit()
bdrv_delete() // frees the bs. Since the device is still connected to
// bs, any subsequent I/O is a use-after-free.
The value of bs->drv becomes unpredictable on free. As long as it
remains null, I/O still gets dropped, however it could become non-null
at any point after the free resulting SEGVs or other QEMU state
corruption.
To resolve this issue as simply as possible, we can chose to not
actually delete the BlockDriverState pointer. Since bdrv_close()
handles setting the drv pointer to NULL, we just need to remove the
BlockDriverState from the QLIST that is used to enumerate the block
devices. This is currently handled within bdrv_delete, so move this
into its own function, bdrv_make_anon().
The result is that we can now invoke drive_del, this closes the file
descriptors and sets BlockDriverState->drv to NULL which prevents futher
IO to the device, and since we do not free BlockDriverState, we don't
have to worry about the copy retained in the block devices.
We also don't attempt to remove the qdev property since we are no longer
deleting the BlockDriverState on drives with associated drives. This
also allows for removing Drives with no devices associated either.
Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Ryan Harper <ryanh@us.ibm.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
If the block device has been closed, we no longer have a medium to submit
IO against, check for this before submitting io. This prevents a segfault
further in the code where we dereference elements of the block driver.
Signed-off-by: Ryan Harper <ryanh@us.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add a trace event for bdrv_aio_flush() to complement the existing
bdrv_aio_readv() and bdrv_aio_writev() events.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Other geometry guessing functions already reside in block.c.
Remove some unused or debugging only fields.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Set block device in use during block migration, disallow drive_del and
bdrv_truncate for in use devices.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Certain operations such as drive_del or resize cannot be performed
while external users (eg. block migration) reference the block device.
Add a flag to indicate that.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Extend the change_cb callback with a reason argument, and use it
to tell drivers about size changes.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The backing format should be honored during image creation. For some
reason we currently use the image format to open the backing file. This
fails when the backing file has a different format than the image being
created. Keep the image and backing format drivers completely separate.
Also print the backing filename if there is an error opening the backing
file instead of the image filename.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Acked-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
