If we are flushing the caches for our image files we only care about the
data (including the metadata required for accessing it) but not things
like timestamp updates. So try to use fdatasync instead of fsync to
implement the flush operations.
Unfortunately many operating systems still do not support fdatasync,
so we add a qemu_fdatasync wrapper that uses fdatasync if available
as per the _POSIX_SYNCHRONIZED_IO feature macro or fsync otherwise.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
One performance problem of qcow2 during the initial image growth are
sequential writes that are not cluster aligned. In this case, when a first
requests requires to allocate a new cluster but writes only to the first
couple of sectors in that cluster, the rest of the cluster is zeroed - just
to be overwritten by the following second request that fills up the cluster.
Let's try to merge sequential write requests to the same cluster, so we can
avoid to write the zero padding to the disk in the first place.
As a nice side effect, also other formats take advantage of dealing with less
and larger requests.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Fix missing strnlen (a GNU extension) problems by using qemu_strnlen
used for user emulators also for system emulators.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Problem: It is impossible to feed filenames with the character colon because
qemu interprets such names as a protocol. For example filename scsi:0, is
interpreted as a protocol by name "scsi".
This patch allows user to espace colon characters. For example the above
filename can now be expressed either as 'scsi\:0' or as file:scsi:0
anything following the "file:" tag is interpreted verbatin. However if "file:"
tag is omitted then any colon characters in the string must be escaped using
backslash.
Here are couple of examples:
scsi\:0\:abc is a local file scsi:0:abc
http\://myweb is a local file by name http://myweb
file:scsi:0:abc is a local file scsi:0:abc
file:http://myweb is a local file by name http://myweb
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Include assert.h from qemu-common.h and remove other direct uses.
cpu-all.h still need to include it because of the dyngen-exec.h hacks
Signed-off-by: Paul Brook <paul@codesourcery.com>
Allow to initialize a QEMUIOVector from an externally allocated iovec.
qiov->nalloc is initialized to -1 to indicate external storage for qiov->iov
and all functions dealing with memory management assert on the iovec beeing
an internally managed first.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6902 c046a42c-6fe2-441c-8c8c-71466251a162
Add a helper to zero out an existing iovec. Removes the need to deallocate
and reallocate it.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6523 c046a42c-6fe2-441c-8c8c-71466251a162
In general, it is not possible to predict the size of of an I/O vector since
a contiguous guest region may map to a disconiguous host region. Add some
helpers to manage I/O vector growth.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6396 c046a42c-6fe2-441c-8c8c-71466251a162
Fix compiler warning on OSX, reported by Andreas Faerber.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5982 c046a42c-6fe2-441c-8c8c-71466251a162
As suggested by Laurent Desnogues.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5872 c046a42c-6fe2-441c-8c8c-71466251a162
This is needed for virtio. The implementation is originally from
Marcelo Tosatti.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5868 c046a42c-6fe2-441c-8c8c-71466251a162
when compiling on NetBSD:
warning: array subscript has type 'char'
Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5727 c046a42c-6fe2-441c-8c8c-71466251a162
The use of strncat and strndup was correct, pstrcpy and pstrdup wasn't.
I'll try to restore building on non-gnu OSes in a later commit.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5651 c046a42c-6fe2-441c-8c8c-71466251a162
Remove QEMU_TOOL. Replace with QEMU_IMG and NEED_CPU_H.
Avoid linking qemu-img against whole system emulatior.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3578 c046a42c-6fe2-441c-8c8c-71466251a162
Christoph Hellwig