Core Dump / panic sleeping thread

[Konstantin Belousov]

On Wed, Mar 20, 2013 at 12:13:05PM +0100, Michael Landin Hostbaek wrote:
> 
> On Mar 20, 2013, at 10:49 AM, Konstantin Belousov <kostikbel at gmail.com> wrote:
> > 
> > I do not like it. As I said in the previous response to Andrey,
> > I think that moving the vnode_pager_setsize() after the unlock is
> > better, since it reduces races with other thread seeing half-done
> > attribute update or making attribute change simultaneously.
> 
> OK - so should I wait for another patch - or? 

I think the following is what I mean. As an additional note, why nfs
client does not trim the buffers when server reported node size change ?

diff --git a/sys/fs/nfsclient/nfs_clport.c b/sys/fs/nfsclient/nfs_clport.c
index a07a67f..4fe2e35 100644
--- a/sys/fs/nfsclient/nfs_clport.c
+++ b/sys/fs/nfsclient/nfs_clport.c
@@ -361,6 +361,8 @@ nfscl_loadattrcache(struct vnode **vpp, struct nfsvattr *nap, void *nvaper,
 	struct nfsnode *np;
 	struct nfsmount *nmp;
 	struct timespec mtime_save;
+	u_quad_t nsize;
+	int setnsize;
 
 	/*
 	 * If v_type == VNON it is a new node, so fill in the v_type,
@@ -418,6 +420,7 @@ nfscl_loadattrcache(struct vnode **vpp, struct nfsvattr *nap, void *nvaper,
 	} else
 		vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
 	np->n_attrstamp = time_second;
+	setnsize = 0;
 	if (vap->va_size != np->n_size) {
 		if (vap->va_type == VREG) {
 			if (dontshrink && vap->va_size < np->n_size) {
@@ -444,10 +447,13 @@ nfscl_loadattrcache(struct vnode **vpp, struct nfsvattr *nap, void *nvaper,
 				np->n_size = vap->va_size;
 				np->n_flag |= NSIZECHANGED;
 			}
-			vnode_pager_setsize(vp, np->n_size);
 		} else {
 			np->n_size = vap->va_size;
 		}
+		if (vap->va_type == VREG || vap->va_type == VDIR) {
+			setnsize = 1;
+			nsize = vap->va_size;
+		}
 	}
 	/*
 	 * The following checks are added to prevent a race between (say)
@@ -480,6 +486,8 @@ nfscl_loadattrcache(struct vnode **vpp, struct nfsvattr *nap, void *nvaper,
 		KDTRACE_NFS_ATTRCACHE_LOAD_DONE(vp, vap, 0);
 #endif
 	NFSUNLOCKNODE(np);
+	if (setnsize)
+		vnode_pager_setsize(vp, nsize);
 	return (0);
 }
 
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