git: 6ddf41faa6f5 - main - swapon: extend the region where the swap vnode is locked

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=6ddf41faa6f54738db9b3f313086974b6403d680

commit 6ddf41faa6f54738db9b3f313086974b6403d680
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2021-11-24 03:06:02 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2021-11-25 19:34:44 +0000

    swapon: extend the region where the swap vnode is locked
    
    to cover VOP_GETATTR() call in sys_swapon().  Move locking from inside
    swapongeom() and swaponvp() into sys_swapon().
    
    Reported by and tested by:      peterj
    Reviewed by:    markj
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D33119
---
 sys/vm/swap_pager.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index 1a44d699bc05..880e2a1894df 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -2366,8 +2366,8 @@ sys_swapon(struct thread *td, struct swapon_args *uap)
 		goto done;
 	}
 
-	NDINIT(&nd, LOOKUP, ISOPEN | FOLLOW | AUDITVNODE1, UIO_USERSPACE,
-	    uap->name, td);
+	NDINIT(&nd, LOOKUP, ISOPEN | FOLLOW | LOCKLEAF | AUDITVNODE1,
+	    UIO_USERSPACE, uap->name, td);
 	error = namei(&nd);
 	if (error)
 		goto done;
@@ -2387,8 +2387,10 @@ sys_swapon(struct thread *td, struct swapon_args *uap)
 		error = swaponvp(td, vp, attr.va_size / DEV_BSIZE);
 	}
 
-	if (error)
-		vrele(vp);
+	if (error != 0)
+		vput(vp);
+	else
+		VOP_UNLOCK(vp);
 done:
 	sx_xunlock(&swdev_syscall_lock);
 	return (error);
@@ -3012,7 +3014,7 @@ swapongeom(struct vnode *vp)
 {
 	int error;
 
-	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+	ASSERT_VOP_ELOCKED(vp, "swapongeom");
 	if (vp->v_type != VCHR || VN_IS_DOOMED(vp)) {
 		error = ENOENT;
 	} else {
@@ -3020,7 +3022,6 @@ swapongeom(struct vnode *vp)
 		error = swapongeom_locked(vp->v_rdev, vp);
 		g_topology_unlock();
 	}
-	VOP_UNLOCK(vp);
 	return (error);
 }
 
@@ -3071,6 +3072,7 @@ swaponvp(struct thread *td, struct vnode *vp, u_long nblks)
 	struct swdevt *sp;
 	int error;
 
+	ASSERT_VOP_ELOCKED(vp, "swaponvp");
 	if (nblks == 0)
 		return (ENXIO);
 	mtx_lock(&sw_dev_mtx);
@@ -3082,14 +3084,12 @@ swaponvp(struct thread *td, struct vnode *vp, u_long nblks)
 	}
 	mtx_unlock(&sw_dev_mtx);
 
-	(void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 #ifdef MAC
 	error = mac_system_check_swapon(td->td_ucred, vp);
 	if (error == 0)
 #endif
 		error = VOP_OPEN(vp, FREAD | FWRITE, td->td_ucred, td, NULL);
-	(void) VOP_UNLOCK(vp);
-	if (error)
+	if (error != 0)
 		return (error);
 
 	swaponsomething(vp, vp, nblks, swapdev_strategy, swapdev_close,