/*===========================================================================*
* put_vnode *
*===========================================================================*/
PUBLIC void put_vnode(struct vnode *vp)
{
/* Decrease vnode's usage counter and decrease inode's usage counter in the
* corresponding FS process. Decreasing the fs_count each time we decrease the
* ref count would lead to poor performance. Instead, only decrease fs_count
* when the ref count hits zero. However, this could lead to fs_count to wrap.
* To prevent this, we drop the counter to 1 when the counter hits 256.
* We maintain fs_count as a sanity check to make sure VFS and the FS are in
* sync.
*/
int r, lock_vp;
ASSERTVP(vp);
/* Lock vnode. It's quite possible this thread already has a lock on this
* vnode. That's no problem, because the reference counter will not decrease
* to zero in that case. However, if the counter does decrease to zero *and*
* is already locked, we have a consistency problem somewhere. */
lock_vp = lock_vnode(vp, VNODE_OPCL);
if (vp->v_ref_count > 1) {
/* Decrease counter */
vp->v_ref_count--;
if (vp->v_fs_count > 256)
vnode_clean_refs(vp);
if (lock_vp != EBUSY) unlock_vnode(vp);
return;
}
/* If we already had a lock, there is a consistency problem */
assert(lock_vp != EBUSY);
tll_upgrade(&vp->v_lock); /* Make sure nobody else accesses this vnode */
/* A vnode that's not in use can't be put back. */
if (vp->v_ref_count <= 0)
panic("put_vnode failed: bad v_ref_count %d\n", vp->v_ref_count);
/* fs_count should indicate that the file is in use. */
if (vp->v_fs_count <= 0)
panic("put_vnode failed: bad v_fs_count %d\n", vp->v_fs_count);
/* Tell FS we don't need this inode to be open anymore. */
r = req_putnode(vp->v_fs_e, vp->v_inode_nr, vp->v_fs_count);
if (r != OK) {
printf("VFS: putnode failed: %d\n", r);
util_stacktrace();
}
/* This inode could've been mapped. If so, tell mapped FS to close it as
* well. If mapped onto same FS, this putnode is not needed. */
if (vp->v_mapfs_e != NONE && vp->v_mapfs_e != vp->v_fs_e)
req_putnode(vp->v_mapfs_e, vp->v_mapinode_nr, vp->v_mapfs_count);
vp->v_fs_count = 0;
vp->v_ref_count = 0;
vp->v_mapfs_count = 0;
unlock_vnode(vp);
}
/*===========================================================================*
* put_vnode *
*===========================================================================*/
PUBLIC void put_vnode(struct vnode *vp)
{
/* Decrease vnode's usage counter and decrease inode's usage counter in the
* corresponding FS process. Decreasing the fs_count each time we decrease the
* ref count would lead to poor performance. Instead, only decrease fs_count
* when the ref count hits zero. However, this could lead to fs_count to wrap.
* To prevent this, we drop the counter to 1 when the counter hits 256.
* We maintain fs_count as a sanity check to make sure VFS and the FS are in
* sync.
*/
ASSERTVP(vp);
if (vp->v_ref_count > 1) {
/* Decrease counter */
vp->v_ref_count--;
if (vp->v_fs_count > 256)
vnode_clean_refs(vp);
return;
}
/* A vnode that's not in use can't be put. */
if (vp->v_ref_count <= 0) {
printf("put_vnode: bad v_ref_count %d\n", vp->v_ref_count);
panic(__FILE__, "put_vnode failed", NO_NUM);
}
/* fs_count should indicate that the file is in use. */
if (vp->v_fs_count <= 0) {
printf("put_vnode: bad v_fs_count %d\n", vp->v_fs_count);
panic(__FILE__, "put_vnode failed", NO_NUM);
}
/* Tell FS we don't need this inode to be open anymore. */
req_putnode(vp->v_fs_e, vp->v_inode_nr, vp->v_fs_count);
/* This inode could've been mapped. If so, tell PFS to close it as well. */
if(vp->v_mapfs_e != 0 && vp->v_mapinode_nr != vp->v_inode_nr &&
vp->v_mapfs_e != vp->v_fs_e) {
req_putnode(vp->v_mapfs_e, vp->v_mapinode_nr, vp->v_mapfs_count);
}
vp->v_fs_count = 0;
vp->v_ref_count = 0;
vp->v_pipe = NO_PIPE;
vp->v_sdev = NO_DEV;
vp->v_mapfs_e = 0;
vp->v_mapinode_nr = 0;
vp->v_mapfs_count = 0;
}
/*===========================================================================*
* vnode_clean_refs *
*===========================================================================*/
void vnode_clean_refs(struct vnode *vp)
{
/* Tell the underlying FS to drop all reference but one. */
if (vp == NIL_VNODE) return;
if (vp->v_fs_count <= 1) return; /* Nothing to do */
/* Drop all references except one */
req_putnode(vp->v_fs_e, vp->v_inode_nr, vp->v_fs_count - 1);
vp->v_fs_count= 1;
}
