8.1-STABLE: zfs and sendfile: problem still exists

[Andriy Gapon]

on 30/10/2010 11:16 Andriy Gapon said the following:
> Or maybe something like the following?
> It looks a little bit cleaner to me, but still is not perfect, as I have not
> handled unnecessary busy-ing of the pages where something more lightweight could
> have sufficed (e.g. wiring and shared busying).

Note: I have only compile tested the patch.

> Index: sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
> ===================================================================
> --- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	(revision 214318)
> +++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	(working copy)
> @@ -67,6 +67,7 @@
>  #include <sys/sf_buf.h>
>  #include <sys/sched.h>
>  #include <sys/acl.h>
> +#include <vm/vm_pageout.h>
> 
>  /*
>   * Programming rules.
> @@ -464,7 +465,7 @@
>  				uiomove_fromphys(&m, off, bytes, uio);
>  			VM_OBJECT_LOCK(obj);
>  			vm_page_wakeup(m);
> -		} else if (m != NULL && uio->uio_segflg == UIO_NOCOPY) {
> +		} else if (uio->uio_segflg == UIO_NOCOPY) {
>  			/*
>  			 * The code below is here to make sendfile(2) work
>  			 * correctly with ZFS. As pointed out by ups@
> @@ -476,6 +477,16 @@
>  			    ("unexpected offset in mappedread for sendfile"));
>  			if (vm_page_sleep_if_busy(m, FALSE, "zfsmrb"))
>  				goto again;
> +			if (m == NULL) {
> +				m = vm_page_alloc(obj, OFF_TO_IDX(start),
> +					    VM_ALLOC_NOBUSY | VM_ALLOC_SYSTEM);
> +				if (m == NULL) {
> +					VM_OBJECT_UNLOCK(obj);
> +					VM_WAIT;
> +					VM_OBJECT_LOCK(obj);
> +					goto again;
> +				}
> +			}
>  			vm_page_busy(m);
>  			VM_OBJECT_UNLOCK(obj);
>  			if (dirbytes > 0) {
> 
> 


-- 
Andriy Gapon