When creating preallocated large raw files opening them with O_DSYNC
prevents long delays in reading because cache pages can be immediately
reused without writing them on a disk first.
In order to avoid problems trying to chown files that were created by
root on a root-squashing nfs server, fork a new process that setuid's
to the desired uid before creating the file. (It's only done this way
if the pool containing the new volume is of type 'netfs', otherwise
the old method of creating the file followed by chown() is used.)
This changes the semantics of the "create_func" slightly - previously
it was assumed that this function just created the file, then the
caller would chown it to the desired uid. Now, create_func does both
operations.
There are multiple functions that can take on the role of create_func:
createFileDir - previously called mkdir(), now calls virDirCreate().
virStorageBackendCreateRaw - previously called open(),
now calls virFileCreate().
virStorageBackendCreateQemuImg - use virRunWithHook() to setuid/gid.
virStorageBackendCreateQcowCreate - same.
virStorageBackendCreateBlockFrom - preserve old behavior (but attempt
chown when necessary even if not root)
* src/storage/storage_backend.[ch] src/storage/storage_backend_disk.c
src/storage/storage_backend_fs.c src/storage/storage_backend_logical.c
src/storage/storage_driver.c: change the create_func implementations,
also propagate the pool information to be able to detect NETFS ones.
Replace free(virBufferContentAndReset()) with virBufferFreeAndReset().
Update documentation and replace all remaining calls to free() with
calls to VIR_FREE(). Also add missing calls to virBufferFreeAndReset()
and virReportOOMError() in OOM error cases.
When building with --disable-nls, I got a few messages like this:
storage/storage_backend.c: In function 'virStorageBackendCreateQemuImg':
storage/storage_backend.c:571: warning: format not a string literal and no format arguments
Fix these up.
Signed-off-by: Chris Lalancette <clalance@redhat.com>
Rename virStorageVolFormatFileSystem to virStorageFileFormat and
move to src/util/storage_file.[ch]
* src/Makefile.am: add src/util/storage_file.[ch]
* src/conf/storage_conf.[ch]: move enum from here ...
* src/util/storage_file.[ch]: .. to here
* src/libvirt_private.syms: update To/FromString exports
* src/storage/storage_backend.c, src/storage/storage_backend_fs.c,
src/vbox/vbox_tmpl.c: update for above changes
