On Tue, Jun 26, 2007 at 11:42:50AM -0400, Andreas Dilger wrote: > On Jun 26, 2007 16:15 +0530, Amit K. Arora wrote: > > On Mon, Jun 25, 2007 at 03:52:39PM -0600, Andreas Dilger wrote: > > > In XFS one of the (many) ALLOC modes is to zero existing data on allocate. > > > For ext4 all this would mean is calling ext4_ext_mark_uninitialized() on > > > each extent. For some workloads this would be much faster than truncate > > > and reallocate of all the blocks in a file. > > > > In ext4, we already mark each extent having preallocated blocks as > > uninitialized. This is done as part of following code (which is part of > > patch 5/7) in ext4_ext_get_blocks() : > > What I meant is that with XFS_IOC_ALLOCSP the previously-written data > is ZEROED OUT, unlike with fallocate() which leaves previously-written > data alone and only allocates in holes. > > In order to specify this for allocation, FA_FL_DEL_DATA would need to make > sense for allocations (as well as the deallocation). This is farily easy > to do - just mark all of the existing extents as unallocated, and their > data disappears. Ok, agreed. Will add the FA_ZERO_SPACE mode too. Thanks! -- Regards, Amit Arora - 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
