check (and fix) mounted-on current directories

SCCS-vsn: sys/kern/vfs_syscalls.c 8.27

diff --git a/usr/src/sys/kern/vfs_syscalls.c b/usr/src/sys/kern/vfs_syscalls.c
index e2f0ac4..b1dcf00 100644 (file)
--- a/usr/src/sys/kern/vfs_syscalls.c
+++ b/usr/src/sys/kern/vfs_syscalls.c
@@ -9,7 +9,7 @@
  *
  * %sccs.include.redist.c%
  *
  *
  * %sccs.include.redist.c%
  *

- *     @(#)vfs_syscalls.c      8.26 (Berkeley) %G%
+ *     @(#)vfs_syscalls.c      8.27 (Berkeley) %G%

  */
 
 #include <sys/param.h>
  */
 
 #include <sys/param.h>


@@ -197,6 +197,7 @@ update:
        cache_purge(vp);
        if (!error) {
                TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
        cache_purge(vp);
        if (!error) {
                TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);

+               checkdirs(vp);

                VOP_UNLOCK(vp);
                vfs_unlock(mp);
                error = VFS_START(mp, 0, p);
                VOP_UNLOCK(vp);
                vfs_unlock(mp);
                error = VFS_START(mp, 0, p);


@@ -209,6 +210,44 @@ update:
        return (error);
 }
 
        return (error);
 }
 

+/*
+ * Scan all active processes to see if any of them have a current
+ * or root directory onto which the new filesystem has just been
+ * mounted. If so, replace them with the new mount point.
+ */
+checkdirs(olddp)
+       struct vnode *olddp;
+{
+       struct filedesc *fdp;
+       struct vnode *newdp;
+       struct proc *p;
+
+       if (olddp->v_usecount == 1)
+               return;
+       if (VFS_ROOT(olddp->v_mountedhere, &newdp))
+               panic("mount: lost mount");
+       for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
+               fdp = p->p_fd;
+               if (fdp->fd_cdir == olddp) {
+                       vrele(fdp->fd_cdir);
+                       VREF(newdp);
+                       fdp->fd_cdir = newdp;
+                       printf("patch cdir for proc %d\n", p->p_pid);
+               }
+               if (fdp->fd_rdir == olddp) {
+                       vrele(fdp->fd_rdir);
+                       VREF(newdp);
+                       fdp->fd_rdir = newdp;
+               }
+       }
+       if (rootvnode == olddp) {
+               vrele(rootvnode);
+               VREF(newdp);
+               rootvnode = newdp;
+       }
+       vput(newdp);
+}
+

 /*
  * Unmount a file system.
  *
 /*
  * Unmount a file system.
  *


@@ -494,22 +533,36 @@ fchdir(p, uap, retval)
        int *retval;
 {
        register struct filedesc *fdp = p->p_fd;
        int *retval;
 {
        register struct filedesc *fdp = p->p_fd;

-       register struct vnode *vp;
+       struct vnode *vp, *tdp;
+       struct mount *mp;

        struct file *fp;
        int error;
 
        if (error = getvnode(fdp, uap->fd, &fp))
                return (error);
        vp = (struct vnode *)fp->f_data;
        struct file *fp;
        int error;
 
        if (error = getvnode(fdp, uap->fd, &fp))
                return (error);
        vp = (struct vnode *)fp->f_data;

+       VREF(vp);

        VOP_LOCK(vp);
        if (vp->v_type != VDIR)
                error = ENOTDIR;
        else
                error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);
        VOP_LOCK(vp);
        if (vp->v_type != VDIR)
                error = ENOTDIR;
        else
                error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);

+       while (!error && (mp = vp->v_mountedhere) != NULL) {
+               if (mp->mnt_flag & MNT_MLOCK) {
+                       mp->mnt_flag |= MNT_MWAIT;
+                       sleep((caddr_t)mp, PVFS);
+                       continue;
+               }
+               if (error = VFS_ROOT(mp, &tdp))
+                       break;
+               vput(vp);
+               vp = tdp;
+       }

        VOP_UNLOCK(vp);
        VOP_UNLOCK(vp);

-       if (error)
+       if (error) {
+               vrele(vp);

                return (error);
                return (error);

-       VREF(vp);
+       }

        vrele(fdp->fd_cdir);
        fdp->fd_cdir = vp;
        return (0);
        vrele(fdp->fd_cdir);
        fdp->fd_cdir = vp;
        return (0);