The generic (naive) implementation of posix_fallocate cannot provide the standard mandated guarantee that overwrites would never fail due to the lack of free space. The fundamental reason is the copy-on-write architecture of ZFS. Other features like compression and deduplication can also increase the size difference between the (pre-)allocated dummy content and the future content. So, until ZFS can properly implement the feature it's better to report that it is unsupported rather than providing an ersatz implementation. Please note that EINVAL is used to report that the underlying file system does not support the operation (POSIX.1-2008). illumos and ZoL seem to do the same. MFC after: 3 weeks Sponsored by: Panzura |
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boot/zfs | ||
compat/opensolaris | ||
contrib/opensolaris | ||
dev |