On Tue, Mar 06, 2007 at 10:46:56AM -0600, Eric Sandeen wrote:

Ulrich Drepper wrote:

quoted

Christoph Hellwig wrote:

quoted

fallocate with the whence argument and flags is already quite complicated,
I'd rather have another call for placement decisions, that would
be called on an fd to do placement decissions for any further allocations
(prealloc, write, etc)

Yes, posix_fallocate shouldn't be made more complicated.  But I don't
understand why requesting linear layout of the blocks should be an
option.  It's always an advantage if the blocks requested this way are
linear on disk.  So, the kernel should always do its best to make this
happen, without needing an additional option.

Agreed on both points.  The hints would be for things like start block,
or speculative EOF preallocation, not contiguity, which I think should
always be the goal.

ISTR having had this discussion before ;)

About guided preallocation for defrag:

http://marc.info/?t=116247859500001&r=1&w=2

e.g.: The sorts of policies we need for effective use of
preallocation:

http://marc.info/?l=linux-fsdevel&m=116184475308164&w=2
http://marc.info/?l=linux-fsdevel&m=116278169519095&w=2

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group