This file and its contents are supplied under the terms of the
Common Development and Distribution License ("CDDL"), version 1.0.
You may only use this file in accordance with the terms of version
1.0 of the CDDL.

A full copy of the text of the CDDL should have accompanied this
source. A copy of the CDDL is also available via the Internet at
http://www.illumos.org/license/CDDL.


Copyright 2008 Sun Microsystems, Inc. All rights reserved.
Copyright 2016 Nexenta Systems, Inc.

.Dd July 26, 2016 .Dt DEVFS_CLEAN 9F .Os .Sh NAME .Nm devfs_clean .Nd destroy unreferenced devfs nodes and detach devices .Sh SYNOPSIS n sys/fs/dv_node.h .Ft int .Fo devfs_clean .Fa "dev_info_t *dip" .Fa "char *devnm" .Fa "uint_t flags" .Fc .Sh INTERFACE LEVEL .Sy Volatile - private DDI function

p This is a private function that is not part of the stable DDI. It may be removed or changed at any time. .Sh PARAMETERS l -tag -width Ds t Va dip A pointer to the device's .Vt dev_info structure. Clean up is rooted at this device. t Va devnm An optional character string used to restrict the devfs nodes list. t Va flags The following flag is supported: l -tag -width "DV_CLEAN_FORCE" t Sy DV_CLEAN_FORCE force clean of referenced directories, referenced empty directories are marked as stale to facilitate DR

q dynamic reconfiguration .El .El .Sh DESCRIPTION The .Fn devfs_clean function is used to clean up and detach devices from the system. While many device drivers may have one or more minor nodes created with .Xr ddi_create_minor_node 9F , some device drivers may have children devices with different device drivers attached. Each of these entries shows up in the file system of the global zone under

a /devices

o see .Xr devfs 7FS

c . These nodes are referred to as a devfs nodes

q Vt dv_node .

p .Nm devfs caches unreferenced devfs nodes to speed up the performance of .Nm ls , .Nm find , etc. The .Fn devfs_clean function is used to cleanup cached nodes to reclaim memory as well as to facilitate device removal

q devfs nodes reference dev_info nodes, which prevents driver from detaching .

p The .Fn devfs_clean function starts searching the tree rooted at .Va dip . All directories encountered are recursed through. If .Va devnm is not NULL, then it is used to limit the nodes that it searches. It compares the name of the node, ignoring any part of the device's name that corresponds to a minor node. If .Va devnm has been specified, then cleanup stops immediately after a busy devfs node has been encountered.

p Not all nodes may be cleaned up when a driver calls the .Fn devfs_clean function. However, this is a non-fatal situation. Callers should continue trying to offline devices as many holds from userland processes may exist due to device contracts which will be released when the device is offlined.

p If a shell parks in a

a /devices directory, the devfs node will be held, preventing the corresponding device to be detached. This would be a denial of service against DR (dynamic reconfiguration). To prevent this, DR code calls .Fn devfs_clean with the .Sy DV_CLEAN_FORCE flag. .Sh CONTEXT This function may be called in user or kernel context. .Sh RETURN VALUES The .Fn devfs_clean function always succeeds and returns zero. .Sh SEE ALSO .Xr devfs 7FS