Requests could return success even though they failed when bdrv_aio_readv
returned NULL for a backing file read.
Reported-by: Chunqiang Tang <ctang@us.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch fixes the following bug in QCOW2. For a QCOW2 image that is larger
than its base image, when handling a read request straddling over the end of the
base image, the QCOW2 driver attempts to read beyond the end of the base image
and the request would fail.
This bug was found by Fast Virtual Disk (FVD)'s fully automated testing tool.
The following test triggered the bug.
dd if=/dev/zero of=/var/ramdisk/truth.raw count=0 bs=1 seek=1098561536
dd if=/dev/zero of=/var/ramdisk/zero-500M.raw count=0 bs=1 seek=593099264
./qemu-img create -f qcow2 -ocluster_size=65536,backing_fmt=blksim -b /var/ramdisk/zero-500M.raw /var/ramdisk/test.qcow2 1098561536
./qemu-io --auto --seed=30477694 --truth=/var/ramdisk/truth.raw --format=qcow2 --test=blksim:/var/ramdisk/test.qcow2 --verify_write=true --compare_before=false --compare_after=true --round=100000 --parallel=100 --io_size=10485760 --fail_prob=0 --cancel_prob=0 --instant_qemubh=true
Signed-off-by: Chunqiang Tang <ctang@us.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Error report from cppcheck:
block/vdi.c:122: error: Using sizeof for array given as function argument returns the size of pointer.
block/vdi.c:128: error: Using sizeof for array given as function argument returns the size of pointer.
Fix both by setting the correct size.
The buggy code is only used when QEMU is build without uuid support.
The bug is not critical, so there is no urgent need to apply it to
old versions of QEMU.
Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
For cache=unsafe we also need to set BDRV_O_CACHE_WB, otherwise we have some
strange unsafe writethrough mode.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Variables l2_modified and l2_size are not really used, remove them.
Spotted by GCC 4.6.0:
CC block/qcow2-refcount.o
/src/qemu/block/qcow2-refcount.c: In function 'qcow2_update_snapshot_refcount':
/src/qemu/block/qcow2-refcount.c:708:37: error: variable 'l2_modified' set but not used [-Werror=unused-but-set-variable]
/src/qemu/block/qcow2-refcount.c:708:9: error: variable 'l2_size' set but not used [-Werror=unused-but-set-variable]
CC: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The consistency check on open is necessary in order to fix inconsistent
table offsets left as a result of a crash mid-operation. Images with a
backing file actually flush before updating table offsets and are
therefore guaranteed to be consistent. Do not mark these images dirty.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This adds a bdrv_discard function to qcow2 that frees the discarded clusters.
It does not yet pass the discard on to the underlying file system driver, but
the space can be reused by future writes to the image.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
This patch parses the input filename in sd_create(), and enables us
specifying a target server to create sheepdog images.
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Move size after the two pointers in struct Qcow2Cache to get better
packing of struct elements on 64 bit architectures.
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
QED relies on the underlying filesystem to extend the file and maintain
its size. Check that images are not created on a block device.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2 calls bdrv_flush() after performing COW in order to ensure that the
L2 table change is never written before the copy is safe on disk. Now that the
L2 table is cached, we can wait with flushing until we write out the next L2
table.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This adds some new cache functions to qcow2 which can be used for caching
refcount blocks and L2 tables. When used with cache=writethrough they work
like the old caching code which is spread all over qcow2, so for this case we
have merely a cleanup.
The interesting case is with writeback caching (this includes cache=none) where
data isn't written to disk immediately but only kept in cache initially. This
leads to some form of metadata write batching which avoids the current "write
to refcount block, flush, write to L2 table" pattern for each single request
when a lot of cluster allocations happen. Instead, cache entries are only
written out if its required to maintain the right order. In the pure cluster
allocation case this means that all metadata updates for requests are done in
memory initially and on sync, first the refcount blocks are written to disk,
then fsync, then L2 tables.
This improves performance of scenarios with lots of cluster allocations
noticably (e.g. installation or after taking a snapshot).
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
cpu_to_be64w() is called with an obviously non-aligned pointer. Use
cpu_to_be64wu() instead. It fixes unaligned accesses errors on IA64
hosts.
Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Fix a file descriptor leak, reported by cppcheck:
[/src/qemu/block/vvfat.c:759]: (error) Resource leak: dir
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
In addition this adds missing braces to the function to be consistent
with the coding style.
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
It doesn't really make sense for functions in qcow2.c to be named
qcow_ so convert the names to match correctly.
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch adds support for the qemu-img check command. It also
introduces a dirty bit in the qed header to mark modified images as
needing a check. This bit is cleared when the image file is closed
cleanly.
If an image file is opened and it has the dirty bit set, a consistency
check will run and try to fix corrupted table offsets. These
corruptions may occur if there is power loss while an allocating write
is performed. Once the image is fixed it opens as normal again.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch implements the read/write state machine. Operations are
fully asynchronous and multiple operations may be active at any time.
Allocating writes lock tables to ensure metadata updates do not
interfere with each other. If two allocating writes need to update the
same L2 table they will run sequentially. If two allocating writes need
to update different L2 tables they will run in parallel.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch adds code to look up data cluster offsets in the image via
the L1/L2 tables. The L2 tables are writethrough cached in memory for
performance (each read/write requires a lookup so it is essential to
cache the tables).
With cluster lookup code in place it is possible to implement
bdrv_is_allocated() to query the number of contiguous
allocated/unallocated clusters.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch introduces the qed on-disk layout and implements image
creation. Later patches add read/write and other functionality.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add support to discard blocks in a raw image residing on an XFS filesystem
by calling the XFS_IOC_UNRESVSP64 ioctl to punch holes. Support for other
hole punching mechanisms can be added when they become available.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add a new bdrv_discard method to free blocks in a mapping image, and a new
drive property to set the granularity for these discard. If no discard
granularity support is set discard support is disabled.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
RBD is an block driver for the distributed file system Ceph
(http://ceph.newdream.net/). This driver uses librados (which is part
of the Ceph server) for direct access to the Ceph object store and is
running entirely in userspace (Yehuda also wrote a driver for the
linux kernel, that can be used to access rbd volumes as a block
device).
Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Christian Brunner <chb@muc.de>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
All drivers use bs->file instead of s->hd for quite a while now, so it's time
to remove s->hd.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
When building on a 64 bit host which uses 'long' for int64_t,
GCC emits a warning:
CC block/blkverify.o
/src/qemu/block/blkverify.c: In function `blkverify_verify_readv':
/src/qemu/block/blkverify.c:304: warning: long long int format, long
unsigned int arg (arg 3)
Rework a77cffe7e9 to avoid the warning.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The cache content may be destroyed after a failed read, better not use it any
more.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
This changes bdrv_flush to return 0 on success and -errno in case of failure.
It's a requirement for implementing proper error handle in users of bdrv_flush.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Move timer init functions to a new file, qemu-timer-common.c. Make other
critical timer functions inlined to preserve performance in
qemu-timer.c, also move muldiv64() (used by the inline functions)
to qemu-timer.h.
Adjust block/raw-posix.c and simpletrace.c to use get_clock() directly.
Remove a similar/duplicate definition in qemu-tool.c.
Adjust hw/omap_clk.c to include qemu-timer.h because muldiv64() is used
there.
After this change, tracing can be used also for user code and
simpletrace on Win32.
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Acked-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Adding the gcc format attribute detects a format bug
which is fixed here.
v2:
Don't use type cast. BDRV_SECTOR_SIZE is unsigned long long,
so %lld should be the correct format specifier.
Cc: Blue Swirl <blauwirbel@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In order to backup snapshots, created from QCOW2 iamge, we want to copy snapshots out of QCOW2 disk to a seperate storage.
The following patch adds a new option in "qemu-img": qemu-img convert -f qcow2 -O qcow2 -s snapshot_name src_img bck_img.
Right now, it only supports to copy the full snapshot, delta snapshot is on the way.
Changes from V1: all the comments from Kevin are addressed:
Add read-only checking
Fix coding style
Change the name from bdrv_snapshot_load to bdrv_snapshot_load_tmp
Signed-off-by: Disheng Su <edison@cloud.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Instead of doing lots of magic for setting up initial refcount blocks and stuff
create a minimal (inconsistent) image, open it and initialize the rest with
regular qcow2 functions.
This is a complete rewrite of the image creation function. The old
implementating is #ifdef'd out and will be removed by the next patch (removing
it here would have made the diff unreadable because diff tries to find
similarities when it's really a rewrite)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The L1 table grow operation includes a size calculation that bumps up
the new L1 table size in order to anticipate the size needs of vmstate
data. This helps reduce the number of times that the L1 table has to be
grown when vmstate data is appended.
This size overhead is not necessary during image creation,
bdrv_truncate(), or snapshot goto operations. In fact, existing
qemu-iotests that exercise table growth are no longer able to trigger it
because image creation preallocates an L1 table that is too large after
changes to qcow_create2().
This patch keeps the size calculation but also adds exact growth for
callers that do not want to inflate the L1 table size unnecessarily.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Compiling with GCC 4.6.0 20100925 produced a warning:
/src/qemu/block/qcow2-refcount.c: In function 'update_refcount':
/src/qemu/block/qcow2-refcount.c:552:13: error: variable 'dummy' set but not used [-Werror=unused-but-set-variable]
Fix by adding a dummy cast so that the result is not unused.
Acked-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Fix this compiler warning:
./block/vvfat.c:2285: error: comparison of unsigned expression >= 0 is always true
Cc: Blue Swirl <blauwirbel@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
The blkverify block driver makes investigating image format data
corruption much easier. A raw image initialized with the same contents
as the test image (e.g. qcow2 file) must be provided. The raw image
mirrors read/write operations and is used to verify that data read from
the test image is correct.
See docs/blkverify.txt for more information.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2 used to use bounce buffers for any AIO requests. This does not only imply
unnecessary copying, but also unbounded allocations which should be avoided.
This patch removes bounce buffers from the normal AIO write path. Encrypted
images continue to use a bounce buffer, however with constant size.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2 used to use bounce buffers for any AIO requests. This does not only imply
unnecessary copying, but also unbounded allocations which should be avoided.
This patch removes bounce buffers from the normal AIO read path, and constrains
them to a constant size for encrypted images.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We always have a sync for the refcount update when a new cluster is
allocated. If we move this past the COW, we can save an additional sync.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Note that the flush is omitted intentionally in qcow2_free_clusters. If
anything, we can leak clusters here if we lose the writes.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block/nbd.c: use default port number when none is specified
qemu-nbd.c: use IANA-assigned port number: 10809
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Replace the hardcoded handling of 512 byte alignment with bs->buffer_alignment
to handle larger sector size devices correctly.
Note that we can not rely on it to be initialize in bdrv_open, so deal
with the worst case there.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The qcow file used for write support in vvfat is a temporary file,
so we can use cache=unsafe there. Without this, write support is just
too slow to be of any use.
Signed-off-by: Kevin Wolf <mail@kevin-wolf.de>
Allocation and deallocation of bs->opaque is not in the control of a
block driver. Therefore it should not set bs->opaque to a data structure
used by another bs, or closing the image will lead to a double free.
Signed-off-by: Kevin Wolf <mail@kevin-wolf.de>
vvfat tries to set the readonly flag in its open function, but nowadays
this is overwritted with the readonly=... command line option. Check in
bdrv_write if the vvfat was opened read-only and return an error in this
case.
Without this check, vvfat tries to access the qcow bs, which is NULL
without enabled write support.
Signed-off-by: Kevin Wolf <mail@kevin-wolf.de>
The signedness of enum types depend on the compiler implementation.
Therefore the check for negative values may or may not be meaningful.
Fix by explicitly casting to a signed integer.
Since the values are also checked earlier against event_names
table, this is an internal error. Change the 'if' to 'assert'.
This also avoids a warning with GCC flag -Wtype-limits.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This reverts commit 79368c81bf.
Conflicts:
block.c
I haven't been able to come up with a solution yet for the corruption caused by
unaligned requests from the IDE disk so revert until a solution can be written.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
When a new cluster was allocated, we only need a flush after the write to the
L2 table if it was a COW and we need to decrease the refcounts of the old
clusters.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Allow symbolic links which point to /dev/sgX devices.
Signed-off-by: Bernhard Kohl <bernhard.kohl@nsn.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
On Linux, we have code to detect CD-ROMs using an ioctl. We shouldn't lose
anything but false positives by removing the check for a /dev/cd* path.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch allows to connect Qemu using NBD protocol to an nbd-server
using named exports.
For instance, if on the host "isoserver", in /etc/nbd-server/config, you have:
[generic]
[debian-500-ppc-netinst]
exportname = /ISO/debian-500-powerpc-netinst.iso
[Fedora-10-ppc-netinst]
exportname = /ISO/Fedora-10-ppc-netinst.iso
You can connect to it, using:
qemu -cdrom nbd:isoserver:exportname=debian-500-ppc-netinst
qemu -cdrom nbd:isoserver:exportname=Fedora-10-ppc-netinst
NOTE: you need at least nbd-server 2.9.18
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
"qemu_socket.h" includes all necessary files and
including <netinet/tcp.h> without <netinet/in.h>
could cause errors on some systems.
Signed-off-by: Izumi Tsutsui <tsutsui@ceres.dti.ne.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Assuming that any image on a block device is not properly zero-initialized is
actually wrong: Only raw images have this problem. Any other image format
shouldn't care about it, they initialize everything properly themselves.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
There is no need to have a second set of integral types.
Replace them by the standard types from stdint.h.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
CVE-2008-2004 described a vulnerability in QEMU whereas a malicious user could
trick the block probing code into accessing arbitrary files in a guest. To
mitigate this, we added an explicit format parameter to -drive which disabling
block probing.
Fast forward to today, and the vast majority of users do not use this parameter.
libvirt does not use this by default nor does virt-manager.
Most users want block probing so we should try to make it safer.
This patch adds some logic to the raw device which attempts to detect a write
operation to the beginning of a raw device. If the first 4 bytes happen to
match an image file that has a backing file that we support, it scrubs the
signature to all zeros. If a user specifies an explicit format parameter, this
behavior is disabled.
I contend that while a legitimate guest could write such a signature to the
header, we would behave incorrectly anyway upon the next invocation of QEMU.
This simply changes the incorrect behavior to not involve a security
vulnerability.
I've tested this pretty extensively both in the positive and negative case. I'm
not 100% confident in the block layer's ability to deal with zero sized writes
particularly with respect to the aio functions so some additional eyes would be
appreciated.
Even in the case of a single sector write, we have to make sure to invoked the
completion from a bottom half so just removing the zero sized write is not an
option.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
WIN32 is not only the system which doesn't have TCP_CORK (e.g. OS X).
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Sheepdog is a distributed storage system for QEMU. It provides highly
available block level storage volumes to VMs like Amazon EBS. This
patch adds a qemu block driver for Sheepdog.
Sheepdog features are:
- No node in the cluster is special (no metadata node, no control
node, etc)
- Linear scalability in performance and capacity
- No single point of failure
- Autonomous management (zero configuration)
- Useful volume management support such as snapshot and cloning
- Thin provisioning
- Autonomous load balancing
The more details are available at the project site:
http://www.osrg.net/sheepdog/
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
raw_pread_aligned() retries up to two times if the block device backs
a virtual CD-ROM (a drive with media=cdrom and if=ide, scsi, xen or
none). This makes no sense. Whether retrying reads can correct read
errors can only depend on what we're reading, not on how the result
gets used. We need to check what whether we're reading from a
physical CD-ROM or floppy here.
I doubt retrying is useful even then. Left for another day.
Impact:
* Virtual CD-ROM backed by host_cdrom behaves the same.
* Virtual CD-ROM backed by file or host_device no longer retries.
* A drive backed by host_cdrom now retries even if it's not a virtual
CD-ROM.
* Any drive backed by host_floppy now retries.
While there, clean up gratuitous use of goto.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This distinguishes between harmless leaks and real corruption. Hopefully users
better understand what qemu-img check wants to tell them.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
state = 0 in rules means that the rule is valid for any state. Therefore it's
impossible to have a rule that works only in the initial state. This changes
the initial state from 0 to 1 to make this possible.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Forgetting to free them means that the next instance inherits all rules and
gets its own rules only additionally.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The list head was initialized to point to the wrong list, so all actions ended
up being handled as inject-error even if they were set-state in fact.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
People were wondering why qemu-img check failed after they tried to preallocate
a large qcow2 file and ran out of disk space.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Trying to check them leads to a second error message which is more confusing
than helpful:
Can't get refcount for cluster 0: Invalid argument
ERROR cluster 0 refcount=-22 reference=1
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
With corrupted images, we can easily get an cluster index that exceeds the
array size of the temporary refcount table.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Use bdrv_(p)write_sync to ensure metadata integrity in case of a crash.
While at it, correct the wrong usage of errno.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Use bdrv_pwrite to access the backing device instead of pread, and
convert the driver to implementing the bdrv_open method which gives
it an already opened BlockDriverState for the underlying device.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We don't have an equivalent to mmap in the qemu block API, so read and
write the bitmap directly. At least in the dumb implementation added
in this patch this is a lot less efficient, but it means cow can also
work on windows, and over nbd or curl. And it fixes qemu-iotests testcase
012 which did not work properly due to issues with read-only mmap access.
In addition we can also get rid of the now unused get_mmap_addr function.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Use pread/pwrite instead of lseek + read/write in preparation of using the
qemu block API.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
If writing the L1 table to disk failed, we need to restore its old content in
memory to avoid inconsistencies.
Reported-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This fixes load_refcount_block which completely ignored the return value of
write_refcount_block and always returned -EIO for bdrv_pwrite failure.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Currently it would consider blocks for which get_refcount fails used. However,
it's unlikely that get_refcount would succeed for the next cluster, so it's not
really helpful. Return an error instead.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
get_refcount might need to load a refcount block from disk, so errors may
happen. Return the error code instead of assuming a refcount of 1 and change
the callers to respect error return values.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This changes the vpc block driver (for VHD) to read/write multiple sectors at
once instead of doing a request for each single sector.
Before this, running qemu-iotests for VPC took ages, now it's actually quite
reasonable to run it always (down from ~1 hour to 40 seconds for me).
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Clean up raw-posix.c to be more consistent using BDRV_SECTOR_SIZE
instead of hard coded 512 values.
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
After it is done with updating refcounts in the cache, update_refcount writes
all changed entries to disk. If a refcount block allocation fails, however,
there was no change yet and therefore first_index = last_index = -1. Don't
treat -1 as a normal sector index (resulting in a 512 byte write!) but return
without updating anything in this case.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Refblock allocation code needs to take into consideration that update_refcount
will load a different refcount block into the cache, so it must initialize the
cache for a new refcount block only afterwards. Not doing this means that not
only the refcount in the wrong block is updated, but also that the caller will
work on the wrong block.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
write_refcount_block_entries used to return -EIO for any errors. Change this to
return the real error code.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qcow2_get_cluster_offset() looks up a given virtual disk offset and returns the
offset of the corresponding cluster in the image file. Errors (e.g. L2 table
can't be read) are currenctly indicated by a return value of 0, which is
unfortuately the same as for any unallocated cluster. So in effect we can't
check for errors.
This makes the old return value a by-reference parameter and returns the usual
0/-errno error code.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
l2_allocate has some intermediate states in which the image is inconsistent.
Change the order to write to the L1 table only after the new L2 table has
successfully been initialized.
Also reset the L2 cache in failure case, it's very likely wrong.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
If the L2 table was already updated in cache, but writing it to disk has
failed, we must not continue using the changed version in the cache to stay
consistent with what's on the disk.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
