8.1-STABLE: zfs and sendfile: problem still exists

[Andriy Gapon]

on 30/10/2010 13:12 Artemiev Igor said the following:
> On Sat, Oct 30, 2010 at 12:52:54PM +0300, Andriy Gapon wrote:
> 
>> Heh, next try.
> 
> Got a panic, "vm_page_unwire: invalid wire count: 0"

Oh, thank you for testing - forgot another piece (VM_ALLOC_WIRE for vm_page_alloc):

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@
@@ -474,9 +475,23 @@
 			 */
 			KASSERT(off == 0,
 			    ("unexpected offset in mappedread for sendfile"));
-			if (vm_page_sleep_if_busy(m, FALSE, "zfsmrb"))
+			if (m != NULL && vm_page_sleep_if_busy(m, FALSE, "zfsmrb"))
 				goto again;
-			vm_page_busy(m);
+			if (m == NULL) {
+				m = vm_page_alloc(obj, OFF_TO_IDX(start),
+				    VM_ALLOC_NOBUSY | VM_ALLOC_WIRE | VM_ALLOC_NORMAL);
+				if (m == NULL) {
+					VM_OBJECT_UNLOCK(obj);
+					VM_WAIT;
+					VM_OBJECT_LOCK(obj);
+					goto again;
+				}
+			} else {
+				vm_page_lock_queues();
+				vm_page_wire(m);
+				vm_page_unlock_queues();
+			}
+			vm_page_io_start(m);
 			VM_OBJECT_UNLOCK(obj);
 			if (dirbytes > 0) {
 				error = dmu_read_uio(os, zp->z_id, uio,
@@ -494,7 +509,10 @@
 			VM_OBJECT_LOCK(obj);
 			if (error == 0)
 				m->valid = VM_PAGE_BITS_ALL;
-			vm_page_wakeup(m);
+			vm_page_io_finish(m);
+			vm_page_lock_queues();
+			vm_page_unwire(m, 0);
+			vm_page_unlock_queues();
 			if (error == 0) {
 				uio->uio_resid -= bytes;
 				uio->uio_offset += bytes;


-- 
Andriy Gapon