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214c687b97
Currently build conditionals decide which of two safezero() functions should be built - either the posix_fallocate() or mmap() with a fallback to a slower safewrite() algorithm in order to preallocate space in a raw file. This patch will refactor safezero to utilize static functions for either posix_fallocate or mmap/safewrite. The build conditional still exist, but are only for shorter sections of code. The posix_fallocate path will make use of the ret/errno setting to contain the logic for safezero to decide whether it needs to fallback to other algorithms. A return of -1 with errno not changed will indicate the conditional is not present; otherwise, a return of -1 with errno change indicates the call was made and it failed (no functional difference to current algorithm). The mmap/safewrite option changes only slightly to handle the ftruncate failure for mmap. That is, previously if the ftruncate failed, there was no fallback to the slow safewrite option. Signed-off-by: John Ferlan <jferlan@redhat.com>
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>