/*===========================================================================*
* is_vnode_locked *
*===========================================================================*/
PUBLIC int is_vnode_locked(struct vnode *vp)
{
/* Find out whether a thread holds a lock on this vnode or is trying to obtain
* a lock. */
ASSERTVP(vp);
return(tll_islocked(&vp->v_lock) || tll_haspendinglock(&vp->v_lock));
}
/*===========================================================================*
* is_vmnt_locked *
*===========================================================================*/
PRIVATE int is_vmnt_locked(struct vmnt *vmp)
{
ASSERTVMP(vmp);
return(tll_islocked(&vmp->m_lock) || tll_haspendinglock(&vmp->m_lock));
}
/*===========================================================================*
* unmount *
*===========================================================================*/
int unmount(
dev_t dev, /* block-special device */
char label[LABEL_MAX] /* buffer to retrieve label, or NULL */
)
{
struct vnode *vp;
struct vmnt *vmp_i = NULL, *vmp = NULL;
int count, locks, r;
/* Find vmnt that is to be unmounted */
for (vmp_i = &vmnt[0]; vmp_i < &vmnt[NR_MNTS]; ++vmp_i) {
if (vmp_i->m_dev == dev) {
if(vmp) panic("device mounted more than once: %d", dev);
vmp = vmp_i;
}
}
/* Did we find the vmnt (i.e., was dev a mounted device)? */
if(!vmp) return(EINVAL);
if ((r = lock_vmnt(vmp, VMNT_EXCL)) != OK) return(r);
/* See if the mounted device is busy. Only 1 vnode using it should be
* open -- the root vnode -- and that inode only 1 time. */
locks = count = 0;
for (vp = &vnode[0]; vp < &vnode[NR_VNODES]; vp++)
if (vp->v_ref_count > 0 && vp->v_dev == dev) {
count += vp->v_ref_count;
if (is_vnode_locked(vp)) locks++;
}
if (count > 1 || locks > 1 || tll_haspendinglock(&vmp->m_lock)) {
unlock_vmnt(vmp);
return(EBUSY); /* can't umount a busy file system */
}
/* Tell FS to drop all inode references for root inode except 1. */
vnode_clean_refs(vmp->m_root_node);
if (vmp->m_mounted_on) {
put_vnode(vmp->m_mounted_on);
vmp->m_mounted_on = NULL;
}
vmp->m_comm.c_max_reqs = 1; /* Force max concurrent reqs to just one, so
* we won't send any messages after the
* unmount request */
/* Tell FS to unmount */
if ((r = req_unmount(vmp->m_fs_e)) != OK) /* Not recoverable. */
printf("VFS: ignoring failed umount attempt FS endpoint: %d (%d)\n",
vmp->m_fs_e, r);
if (is_nonedev(vmp->m_dev)) free_nonedev(vmp->m_dev);
if (label != NULL) strlcpy(label, vmp->m_label, LABEL_MAX);
if (vmp->m_root_node) { /* PFS lacks a root node */
vmp->m_root_node->v_ref_count = 0;
vmp->m_root_node->v_fs_count = 0;
vmp->m_root_node->v_sdev = NO_DEV;
vmp->m_root_node = NULL;
}
mark_vmnt_free(vmp);
unlock_vmnt(vmp);
/* The root FS will handle block I/O requests for this device now. */
lock_bsf();
update_bspec(dev, ROOT_FS_E, 1 /* send new driver endpoint */);
unlock_bsf();
return(OK);
}
