Module Name: src
Committed By: hannken
Date: Tue Apr 11 07:46:38 UTC 2017
Modified Files:
src/sys/kern: vfs_mount.c
src/sys/sys: mount.h
Log Message:
Add an iterator over the currently mounted file systems.
Ride 7.99.68
To generate a diff of this commit:
cvs rdiff -u -r1.51 -r1.52 src/sys/kern/vfs_mount.c
cvs rdiff -u -r1.221 -r1.222 src/sys/sys/mount.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/vfs_mount.c
diff -u src/sys/kern/vfs_mount.c:1.51 src/sys/kern/vfs_mount.c:1.52
--- src/sys/kern/vfs_mount.c:1.51 Thu Mar 30 09:13:01 2017
+++ src/sys/kern/vfs_mount.c Tue Apr 11 07:46:37 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_mount.c,v 1.51 2017/03/30 09:13:01 hannken Exp $ */
+/* $NetBSD: vfs_mount.c,v 1.52 2017/04/11 07:46:37 hannken Exp $ */
/*-
* Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.51 2017/03/30 09:13:01 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.52 2017/04/11 07:46:37 hannken Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@@ -94,6 +94,22 @@ __KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,
#include <miscfs/genfs/genfs.h>
#include <miscfs/specfs/specdev.h>
+enum mountlist_type {
+ ME_MOUNT,
+ ME_MARKER
+};
+struct mountlist_entry {
+ TAILQ_ENTRY(mountlist_entry) me_list; /* Mount list. */
+ struct mount *me_mount; /* Actual mount if ME_MOUNT,
+ current mount else. */
+ enum mountlist_type me_type; /* Mount or marker. */
+};
+struct mount_iterator {
+ struct mountlist_entry mi_entry;
+};
+
+static TAILQ_HEAD(mountlist, mountlist_entry) mount_list;
+
static struct vnode *vfs_vnode_iterator_next1(struct vnode_iterator *,
bool (*)(void *, struct vnode *), void *, bool);
@@ -119,6 +135,7 @@ void
vfs_mount_sysinit(void)
{
+ TAILQ_INIT(&mount_list);
TAILQ_INIT(&mountlist);
mutex_init(&mountlist_lock, MUTEX_DEFAULT, IPL_NONE);
mutex_init(&mntvnode_lock, MUTEX_DEFAULT, IPL_NONE);
@@ -769,9 +786,7 @@ mount_domount(struct lwp *l, vnode_t **v
cache_purge(vp);
mp->mnt_iflag &= ~IMNT_WANTRDWR;
- mutex_enter(&mountlist_lock);
- TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
- mutex_exit(&mountlist_lock);
+ mountlist_append(mp);
if ((mp->mnt_flag & (MNT_RDONLY | MNT_ASYNC)) == 0)
vfs_syncer_add_to_worklist(mp);
vp->v_mountedhere = mp;
@@ -931,9 +946,7 @@ dounmount(struct mount *mp, int flags, s
coveredvp->v_mountedhere = NULL;
VOP_UNLOCK(coveredvp);
}
- mutex_enter(&mountlist_lock);
- TAILQ_REMOVE(&mountlist, mp, mnt_list);
- mutex_exit(&mountlist_lock);
+ mountlist_remove(mp);
if (TAILQ_FIRST(&mp->mnt_vnodelist) != NULL)
panic("unmount: dangling vnode");
if (used_syncer)
@@ -1439,10 +1452,156 @@ makefstype(const char *type)
return rv;
}
+static struct mountlist_entry *
+mountlist_alloc(enum mountlist_type type, struct mount *mp)
+{
+ struct mountlist_entry *me;
+
+ me = kmem_zalloc(sizeof(*me), KM_SLEEP);
+ me->me_mount = mp;
+ me->me_type = type;
+
+ return me;
+}
+
+static void
+mountlist_free(struct mountlist_entry *me)
+{
+
+ kmem_free(me, sizeof(*me));
+}
+
+void
+mountlist_iterator_init(mount_iterator_t **mip)
+{
+ struct mountlist_entry *me;
+
+ me = mountlist_alloc(ME_MARKER, NULL);
+ mutex_enter(&mountlist_lock);
+ TAILQ_INSERT_HEAD(&mount_list, me, me_list);
+ mutex_exit(&mountlist_lock);
+ *mip = (mount_iterator_t *)me;
+}
+
+void
+mountlist_iterator_destroy(mount_iterator_t *mi)
+{
+ struct mountlist_entry *marker = &mi->mi_entry;
+
+ if (marker->me_mount != NULL)
+ vfs_unbusy(marker->me_mount, false, NULL);
+
+ mutex_enter(&mountlist_lock);
+ TAILQ_REMOVE(&mount_list, marker, me_list);
+ mutex_exit(&mountlist_lock);
+
+ mountlist_free(marker);
+
+}
+
+/*
+ * Return the next mount or NULL for this iterator.
+ * Mark it busy on success.
+ */
+struct mount *
+mountlist_iterator_next(mount_iterator_t *mi)
+{
+ struct mountlist_entry *me, *marker = &mi->mi_entry;
+ struct mount *mp;
+
+ if (marker->me_mount != NULL) {
+ vfs_unbusy(marker->me_mount, false, NULL);
+ marker->me_mount = NULL;
+ }
+
+ mutex_enter(&mountlist_lock);
+ for (;;) {
+ KASSERT(marker->me_type == ME_MARKER);
+
+ me = TAILQ_NEXT(marker, me_list);
+ if (me == NULL) {
+ /* End of list: keep marker and return. */
+ mutex_exit(&mountlist_lock);
+ return NULL;
+ }
+ TAILQ_REMOVE(&mount_list, marker, me_list);
+ TAILQ_INSERT_AFTER(&mount_list, me, marker, me_list);
+
+ /* Skip other markers. */
+ if (me->me_type != ME_MOUNT)
+ continue;
+
+ /* Take an initial reference for vfs_busy() below. */
+ mp = me->me_mount;
+ KASSERT(mp != NULL);
+ atomic_inc_uint(&mp->mnt_refcnt);
+ mutex_exit(&mountlist_lock);
+
+ /* Try to mark this mount busy and return on success. */
+ if (vfs_busy(mp, NULL) == 0) {
+ vfs_destroy(mp);
+ marker->me_mount = mp;
+ return mp;
+ }
+ vfs_destroy(mp);
+ mutex_enter(&mountlist_lock);
+ }
+}
+
+/*
+ * Attach new mount to the end of the mount list.
+ */
void
mountlist_append(struct mount *mp)
{
+ struct mountlist_entry *me;
+
+ me = mountlist_alloc(ME_MOUNT, mp);
mutex_enter(&mountlist_lock);
+ TAILQ_INSERT_TAIL(&mount_list, me, me_list);
TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
mutex_exit(&mountlist_lock);
}
+
+/*
+ * Remove mount from mount list.
+ */void
+mountlist_remove(struct mount *mp)
+{
+ struct mountlist_entry *me;
+
+ mutex_enter(&mountlist_lock);
+ TAILQ_FOREACH(me, &mount_list, me_list)
+ if (me->me_type == ME_MOUNT && me->me_mount == mp)
+ break;
+ KASSERT(me != NULL);
+ TAILQ_REMOVE(&mount_list, me, me_list);
+ TAILQ_REMOVE(&mountlist, mp, mnt_list);
+ mutex_exit(&mountlist_lock);
+ mountlist_free(me);
+}
+
+/*
+ * Unlocked variant to traverse the mountlist.
+ * To be used from DDB only.
+ */
+struct mount *
+_mountlist_next(struct mount *mp)
+{
+ struct mountlist_entry *me;
+
+ if (mp == NULL) {
+ me = TAILQ_FIRST(&mount_list);
+ } else {
+ TAILQ_FOREACH(me, &mount_list, me_list)
+ if (me->me_type == ME_MOUNT && me->me_mount == mp)
+ break;
+ if (me != NULL)
+ me = TAILQ_NEXT(me, me_list);
+ }
+
+ while (me != NULL && me->me_type != ME_MOUNT)
+ me = TAILQ_NEXT(me, me_list);
+
+ return (me ? me->me_mount : NULL);
+}
Index: src/sys/sys/mount.h
diff -u src/sys/sys/mount.h:1.221 src/sys/sys/mount.h:1.222
--- src/sys/sys/mount.h:1.221 Mon Mar 6 10:10:07 2017
+++ src/sys/sys/mount.h Tue Apr 11 07:46:37 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: mount.h,v 1.221 2017/03/06 10:10:07 hannken Exp $ */
+/* $NetBSD: mount.h,v 1.222 2017/04/11 07:46:37 hannken Exp $ */
/*
* Copyright (c) 1989, 1991, 1993
@@ -494,7 +494,14 @@ void * mount_getspecific(struct mount *,
void mount_setspecific(struct mount *, specificdata_key_t, void *);
int usermount_common_policy(struct mount *, u_long);
+
+typedef struct mount_iterator mount_iterator_t; /* Opaque. */
+void mountlist_iterator_init(mount_iterator_t **);
+void mountlist_iterator_destroy(mount_iterator_t *);
+struct mount *mountlist_iterator_next(mount_iterator_t *);
+struct mount *_mountlist_next(struct mount *);
void mountlist_append(struct mount *);
+void mountlist_remove(struct mount *);
LIST_HEAD(vfs_list_head, vfsops);
extern struct vfs_list_head vfs_list;
