Summary: when writing to a PUFFS filesystem through page cache, we do not know if backend storage is really available. If it is not, cache flush may get EDQUOT or ENOSPC and the process cannot terminate (it gets stuck in DE state).
Proposed solution: detect that a write may not have backend storage, and if it is the case, try to allocate the backend storage. Detecting is done on two conditions: - if allocated blocks is shorter than size, the file is sparse and we never know if we are writing in a hole or not: in that case, always write-once - if writing beyond EOF Allocating the backend storage is done - through newly introduced PUFFS fallocate operation (unlikely to work on NetBSD as the system call exists but FFS does not support it) - otherwise by reading from the file and rewriting the readen data The latest patch doing this: http://ftp.espci.fr/shadow/manu/puffs-alloc2.patch Opinions? -- Emmanuel Dreyfus http://hcpnet.free.fr/pubz m...@netbsd.org
