Author: avg
Date: Thu Oct 5 07:16:31 2017
New Revision: 324295
URL: https://svnweb.freebsd.org/changeset/base/324295
Log:
MFC r323578,r323769: dounmount: do not release the mount point's reference
on the covered vnode
As long as mnt_ref is not zero there can be a consumer that might try
to access mnt_vnodecovered. For this reason the covered vnode must not
be freed until mnt_ref goes to zero.
So, move the release of the covered vnode to vfs_mount_destroy.
Modified:
stable/10/sys/cddl/compat/opensolaris/kern/opensolaris_vfs.c
stable/10/sys/kern/vfs_mount.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/cddl/compat/opensolaris/kern/opensolaris_vfs.c
==============================================================================
--- stable/10/sys/cddl/compat/opensolaris/kern/opensolaris_vfs.c Thu Oct
5 07:10:28 2017 (r324294)
+++ stable/10/sys/cddl/compat/opensolaris/kern/opensolaris_vfs.c Thu Oct
5 07:16:31 2017 (r324295)
@@ -209,6 +209,7 @@ mount_snapshot(kthread_t *td, vnode_t **vpp, const cha
vput(vp);
vfs_unbusy(mp);
vfs_freeopts(mp->mnt_optnew);
+ mp->mnt_vnodecovered = NULL;
vfs_mount_destroy(mp);
return (error);
}
Modified: stable/10/sys/kern/vfs_mount.c
==============================================================================
--- stable/10/sys/kern/vfs_mount.c Thu Oct 5 07:10:28 2017
(r324294)
+++ stable/10/sys/kern/vfs_mount.c Thu Oct 5 07:16:31 2017
(r324295)
@@ -521,6 +521,8 @@ vfs_mount_destroy(struct mount *mp)
if (mp->mnt_lockref != 0)
panic("vfs_mount_destroy: nonzero lock refcount");
MNT_IUNLOCK(mp);
+ if (mp->mnt_vnodecovered != NULL)
+ vrele(mp->mnt_vnodecovered);
#ifdef MAC
mac_mount_destroy(mp);
#endif
@@ -818,6 +820,7 @@ vfs_domount_first(
error = VFS_MOUNT(mp);
if (error != 0) {
vfs_unbusy(mp);
+ mp->mnt_vnodecovered = NULL;
vfs_mount_destroy(mp);
VI_LOCK(vp);
vp->v_iflag &= ~VI_MOUNT;
@@ -1379,7 +1382,7 @@ dounmount(struct mount *mp, int flags, struct thread *
EVENTHANDLER_INVOKE(vfs_unmounted, mp, td);
if (coveredvp != NULL) {
coveredvp->v_mountedhere = NULL;
- vput(coveredvp);
+ VOP_UNLOCK(coveredvp, 0);
}
vfs_event_signal(NULL, VQ_UNMOUNT, 0);
if (mp == rootdevmp)
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