On Tue, Oct 09, 2012 at 05:59:06PM -0700, Chuck Silvers wrote:
>
> if so, then the reason for the 64k writes would be this block of code in
> ffs_write():
>
> if (!async && oldoff >> 16 != uio->uio_offset >> 16) {
> mutex_enter(vp->v_interlock);
> error = VOP_PUTPAGES(vp, (oldoff >> 16) << 16,
> (uio->uio_offset >> 16) << 16,
> PGO_CLEANIT | PGO_JOURNALLOCKED | PGO_LAZY);
> if (error)
> break;
> }
Upon reflection, I do not understand how this works.
Consider a write() of 131072 starting at file offset 0.
oldoff >> 16 will be 0; uio->uio_offset will be 131072, unless
this is the source of my misunderstanding, after the call to ubc_uiomove().
Otherwise, I don't see how uio->uio_offset gets updated at all.
Now, we VOP_PUTPAGES(vp, 0, (131072 >> 16) << 16)) which is of course
VOP_PUTPAGES(vp, 0, 131072). So why does this only push out 64K?
Thor
