git: db5655124ca4 - main - vfs_mount.c: Free exports structures in vfs_destroy_mount()

The branch main has been updated by rmacklem:

URL: https://cgit.FreeBSD.org/src/commit/?id=db5655124ca4047ac397b9421ca4a08868a49ae9

commit db5655124ca4047ac397b9421ca4a08868a49ae9
Author:     Rick Macklem <rmacklem@FreeBSD.org>
AuthorDate: 2023-02-04 22:45:23 +0000
Commit:     Rick Macklem <rmacklem@FreeBSD.org>
CommitDate: 2023-02-04 22:45:23 +0000

    vfs_mount.c: Free exports structures in vfs_destroy_mount()
    
    During testing of exporting file systems in jails, I
    noticed that the export structures on a mount
    were not being free'd when the mount is dismounted.
    
    This bug appears to have been in the system for a
    very long time.  It would have resulted in a slow memory
    leak when exported file systems were dismounted.
    
    Prior to r362158, freeing the structures during dismount
    would not have been safe, since VFS_CHECKEXP() returned
    a pointer into an export structure, which might still have been
    used by the NFS server for an in-progress RPC when the file system
    is dismounted.  r362158 fixed this, so it should now be safe
    to free the structures in vfs_mount_destroy(), which is what
    this patch does.
    
    Reviewed by:    kib
    MFC after:      1 month
    Differential Revision:  https://reviews.freebsd.org/D38385
---
 sys/kern/vfs_export.c | 7 ++++---
 sys/kern/vfs_mount.c  | 4 ++++
 sys/sys/mount.h       | 1 +
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/sys/kern/vfs_export.c b/sys/kern/vfs_export.c
index 024011de4c89..cab37ce205ad 100644
--- a/sys/kern/vfs_export.c
+++ b/sys/kern/vfs_export.c
@@ -70,7 +70,6 @@ static MALLOC_DEFINE(M_NETADDR, "export_host", "Export host address structure");
 static struct radix_node_head *vfs_create_addrlist_af(
 		    struct radix_node_head **prnh, int off);
 #endif
-static void	vfs_free_addrlist(struct netexport *nep);
 static int	vfs_free_netcred(struct radix_node *rn, void *w);
 static void	vfs_free_addrlist_af(struct radix_node_head **prnh);
 static int	vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
@@ -274,7 +273,7 @@ vfs_free_addrlist_af(struct radix_node_head **prnh)
 /*
  * Free the net address hash lists that are hanging off the mount points.
  */
-static void
+void
 vfs_free_addrlist(struct netexport *nep)
 {
 	struct ucred *cred;
@@ -285,8 +284,10 @@ vfs_free_addrlist(struct netexport *nep)
 		vfs_free_addrlist_af(&nep->ne6);
 
 	cred = nep->ne_defexported.netc_anon;
-	if (cred != NULL)
+	if (cred != NULL) {
 		crfree(cred);
+		nep->ne_defexported.netc_anon = NULL;
+	}
 
 }
 
diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
index 67a72f095786..430bafc8502f 100644
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -761,6 +761,10 @@ vfs_mount_destroy(struct mount *mp)
 #endif
 	if (mp->mnt_opt != NULL)
 		vfs_freeopts(mp->mnt_opt);
+	if (mp->mnt_export != NULL) {
+		vfs_free_addrlist(mp->mnt_export);
+		free(mp->mnt_export, M_MOUNT);
+	}
 	crfree(mp->mnt_cred);
 	uma_zfree(mount_zone, mp);
 }
diff --git a/sys/sys/mount.h b/sys/sys/mount.h
index 4bfc77b7f1a1..5f02f261b8f4 100644
--- a/sys/sys/mount.h
+++ b/sys/sys/mount.h
@@ -1017,6 +1017,7 @@ void	vfs_periodic(struct mount *, int);
 int	vfs_busy(struct mount *, int);
 int	vfs_export			 /* process mount export info */
 	    (struct mount *, struct export_args *);
+void	vfs_free_addrlist(struct netexport *);
 void	vfs_allocate_syncvnode(struct mount *);
 void	vfs_deallocate_syncvnode(struct mount *);
 int	vfs_donmount(struct thread *td, uint64_t fsflags,