On Thu, Jul 12, 2007 at 12:58:13PM +0530, Suparna Bhattacharya wrote: > On Wed, Jul 11, 2007 at 10:03:12AM +0100, Christoph Hellwig wrote: > > On Tue, Jul 03, 2007 at 05:16:50PM +0530, Amit K. Arora wrote: > > > Well, if you see the modes proposed using above flags : > > > > > > #define FA_ALLOCATE 0 > > > #define FA_DEALLOCATE FA_FL_DEALLOC > > > #define FA_RESV_SPACE FA_FL_KEEP_SIZE > > > #define FA_UNRESV_SPACE (FA_FL_DEALLOC | FA_FL_KEEP_SIZE | FA_FL_DEL_DATA) > > > > > > FA_FL_DEL_DATA is _not_ being used for preallocation. We have two modes > > > for preallocation FA_ALLOCATE and FA_RESV_SPACE, which do not use this > > > flag. Hence prealloction will never delete data. > > > This mode is required only for FA_UNRESV_SPACE, which is a deallocation > > > mode, to support any existing XFS aware applications/usage-scenarios. > > > > Sorry, but this doesn't make any sense. There is no need to put every > > feature in the XFS ioctls in the syscalls. The XFS ioctls will need to > > be supported forever anyway - as I suggested before they really should > > be moved to generic code. > > > > What needs to be supported is what makes sense as an interface. > > A punch a hole interface does make sense, but trying to hack this into > > a preallocation system call is just madness. We're not IRIX or windows > > that fit things into random subcall just because there was some space > > left to squeeze them in. > > > > > > > > FA_FL_NO_MTIME 0x10 /* keep same mtime (default change on size, data change) */ > > > > > > FA_FL_NO_CTIME 0x20 /* keep same ctime (default change on size, data change) */ > > > > > > > > NACK to these aswell. If i_size changes c/mtime need updates, if the size > > > > doesn't chamge they don't. No need to add more flags for this. > > > > > > This requirement was from the point of view of HSM applications. Hope > > > you saw Andreas previous post and are keeping that in mind. > > > > HSMs needs this basically for every system call, which screams for an > > open flag like O_INVISIBLE anyway. Adding this in a generic way is > > a good idea, but hacking bits and pieces that won't fit into the global > > design is completely wrong. > > Why don't we just merge the interface for preallocation (essentially > enough to satisfy posix_fallocate() and the simple XFS requirement for > space reservation without changing file size), which there is clear agreement > on (I hope :)). After all, this was all that we set out to do when we > started. As you suggest, let us just have two modes for the time being: #define FALLOC_ALLOCATE 0x1 #define FALLOC_ALLOCATE_KEEP_SIZE 0x2 As the name suggests, when FALLOC_ALLOCATE_KEEP_SIZE mode is passed it will result in file size not being changed even if the preallocation is beyond EOF. > And leave all the dealloc/punch/hsm type features for separate future patches/ > debates, those really shouldn't hold up the basic fallocate interface. I agree. > I agree with Christoph that we are just diverging too much in trying to > club those decisions here. > > Dave, Andreas, Ted ? > > Regards > Suparna -- Regards, Amit Arora - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
