On May 09, 2007 21:31 +0530, Amit K. Arora wrote: > 2) For FA_UNALLOCATE mode, should the file system allow unallocation > of normal (non-preallocated) blocks (blocks allocated via > regular write/truncate operations) also (i.e. work as punch()) ? > - Though FA_UNALLOCATE mode is yet to be implemented on ext4, still > we need to finalize on the convention here as a general guideline > to all the filesystems that implement fallocate. I would only allow this on FA_ALLOCATE extents. That means it won't be possible to do this for filesystems that don't understand unwritten extents unless there are blocks allocated beyond EOF. > 3) If above is true, the file size will need to be changed > for "unallocation" when block holding the EOF gets unallocated. > - If we do not "unallocate" normal (non-preallocated) blocks and we > do not change the file size on preallocation, then this is a > non-issue. Not necessarily. That will just make the file sparse. If FA_ALLOCATE does not change the file size, why should FA_UNALLOCATE. > 4) Should we update mtime & ctime on a successfull allocation/ > unallocation ? I would say yes. If glibc does the fallback fallocate via write() the mtime/ctime will be updated, so it makes sense to be consistent for both methods. Also, it just makes sense from the "this file was modified" point of view. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc. - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
