* Christoph Hellwig: > The glibc implementation in sysdeps/posix/posix_fallocate.c, which is > also by sysdeps/unix/sysv/linux/posix_fallocate.c as a fallback if the > fallocate syscall returns EOPNOTSUPP is implemented by doing single > byte writes at intervals of min(f.f_bsize, 4096). > How can we get rid of this glibc fallback that turns the implementations > non-conformant and increases write amplication for no good reason? When does the kernel return EOPNOTSUPP these days? We do not even do fallback for EPERM/ENOSYS, those that might be encountered in containers. Last time I looked at this I concluded that it does not make sense to push this write loop from glibc to the applications. That's what would happen if we had a new version of posix_fallocate that didn't do those writes. We also updated the manual: Storage Allocation <https://sourceware.org/glibc/manual/latest/html_node/Storage-Allocation.html> As mentioned, if an application doesn't want fallback behavior, it can call fallocate directly. Thanks, Florian
