/* getroot.c: get the root dentry for an NFS mount
 *
 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/init.h>

#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/stats.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/lockd/bind.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/vfs.h>
#include <linux/namei.h>
#include <linux/security.h>

#include <linux/uaccess.h>

#include "internal.h"

#define NFSDBG_FACILITY		NFSDBG_CLIENT

/*
 * Set the superblock root dentry.
 * Note that this function frees the inode in case of error.
 */
static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode)
{
	/* The mntroot acts as the dummy root dentry for this superblock */
	if (sb->s_root == NULL) {
		sb->s_root = d_make_root(inode);
		if (sb->s_root == NULL)
			return -ENOMEM;
		ihold(inode);
		/*
		 * Ensure that this dentry is invisible to d_find_alias().
		 * Otherwise, it may be spliced into the tree by
		 * d_splice_alias if a parent directory from the same
		 * filesystem gets mounted at a later time.
		 * This again causes shrink_dcache_for_umount_subtree() to
		 * Oops, since the test for IS_ROOT() will fail.
		 */
		spin_lock(&d_inode(sb->s_root)->i_lock);
		spin_lock(&sb->s_root->d_lock);
		hlist_del_init(&sb->s_root->d_u.d_alias);
		spin_unlock(&sb->s_root->d_lock);
		spin_unlock(&d_inode(sb->s_root)->i_lock);
	}
	return 0;
}

/*
 * get an NFS2/NFS3 root dentry from the root filehandle
 */
struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh,
			    const char *devname)
{
	struct nfs_server *server = NFS_SB(sb);
	struct nfs_fsinfo fsinfo;
	struct dentry *ret;
	struct inode *inode;
	void *name = kstrdup(devname, GFP_KERNEL);
	int error;

	if (!name)
		return ERR_PTR(-ENOMEM);

	/* get the actual root for this mount */
	fsinfo.fattr = nfs_alloc_fattr();
	if (fsinfo.fattr == NULL) {
		kfree(name);
		return ERR_PTR(-ENOMEM);
	}

	error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
	if (error < 0) {
		dprintk("nfs_get_root: getattr error = %d\n", -error);
		ret = ERR_PTR(error);
		goto out;
	}

	inode = nfs_fhget(sb, mntfh, fsinfo.fattr, NULL);
	if (IS_ERR(inode)) {
		dprintk("nfs_get_root: get root inode failed\n");
		ret = ERR_CAST(inode);
		goto out;
	}

	error = nfs_superblock_set_dummy_root(sb, inode);
	if (error != 0) {
		ret = ERR_PTR(error);
		goto out;
	}

	/* root dentries normally start off anonymous and get spliced in later
	 * if the dentry tree reaches them; however if the dentry already
	 * exists, we'll pick it up at this point and use it as the root
	 */
	ret = d_obtain_root(inode);
	if (IS_ERR(ret)) {
		dprintk("nfs_get_root: get root dentry failed\n");
		goto out;
	}

	security_d_instantiate(ret, inode);
	spin_lock(&ret->d_lock);
	if (IS_ROOT(ret) && !ret->d_fsdata &&
	    !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
		ret->d_fsdata = name;
		name = NULL;
	}
	spin_unlock(&ret->d_lock);
out:
	kfree(name);
	nfs_free_fattr(fsinfo.fattr);
	return ret;
}
option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-27 12:54:16 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-27 12:54:16 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/llc?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>1b1bc42c1692e9b62756323c675a44cb1a1f9dbd</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/llc?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>d514a2d8512fc52c15747841e2368f8f99a50787</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/llc?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>net/llc</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/llc?id=3365135d43f861003555c963b309672d053a2228'>3365135d43f861003555c963b309672d053a2228</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/llc?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd&amp;id2=3365135d43f861003555c963b309672d053a2228'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/llc?id=950eabbd6ddedc1b08350b9169a6a51b130ebaaf'>950eabbd6ddedc1b08350b9169a6a51b130ebaaf</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/llc?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd&amp;id2=950eabbd6ddedc1b08350b9169a6a51b130ebaaf'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net</div><div class='commit-msg'>Pull networking fixes from David Miller:

 1) GTP fixes from Andreas Schultz (missing genl module alias, clear IP
    DF on transmit).

 2) Netfilter needs to reflect the fwmark when sending resets, from Pau
    Espin Pedrol.

 3) nftable dump OOPS fix from Liping Zhang.

 4) Fix erroneous setting of VIRTIO_NET_HDR_F_DATA_VALID on transmit,
    from Rolf Neugebauer.

 5) Fix build error of ipt_CLUSTERIP when procfs is disabled, from Arnd
    Bergmann.

 6) Fix regression in handling of NETIF_F_SG in harmonize_features(),
    from Eric Dumazet.

 7) Fix RTNL deadlock wrt. lwtunnel module loading, from David Ahern.

 8) tcp_fastopen_create_child() needs to setup tp-&gt;max_window, from
    Alexey Kodanev.

 9) Missing kmemdup() failure check in ipv6 segment routing code, from
    Eric Dumazet.

10) Don't execute unix_bind() under the bindlock, otherwise we deadlock
    with splice. From WANG Cong.

11) ip6_tnl_parse_tlv_enc_lim() potentially reallocates the skb buffer,
    therefore callers must reload cached header pointers into that skb.
    Fix from Eric Dumazet.

12) Fix various bugs in legacy IRQ fallback handling in alx driver, from
    Tobias Regnery.

13) Do not allow lwtunnel drivers to be unloaded while they are
    referenced by active instances, from Robert Shearman.

14) Fix truncated PHY LED trigger names, from Geert Uytterhoeven.

15) Fix a few regressions from virtio_net XDP support, from John
    Fastabend and Jakub Kicinski.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (102 commits)
  ISDN: eicon: silence misleading array-bounds warning
  net: phy: micrel: add support for KSZ8795
  gtp: fix cross netns recv on gtp socket
  gtp: clear DF bit on GTP packet tx
  gtp: add genl family modules alias
  tcp: don't annotate mark on control socket from tcp_v6_send_response()
  ravb: unmap descriptors when freeing rings
  virtio_net: reject XDP programs using header adjustment
  virtio_net: use dev_kfree_skb for small buffer XDP receive
  r8152: check rx after napi is enabled
  r8152: re-schedule napi for tx
  r8152: avoid start_xmit to schedule napi when napi is disabled
  r8152: avoid start_xmit to call napi_schedule during autosuspend
  net: dsa: Bring back device detaching in dsa_slave_suspend()
  net: phy: leds: Fix truncated LED trigger names
  net: phy: leds: Break dependency of phy.h on phy_led_triggers.h
  net: phy: leds: Clear phy_num_led_triggers on failure to avoid crash
  net-next: ethernet: mediatek: change the compatible string
  Documentation: devicetree: change the mediatek ethernet compatible string
  bnxt_en: Fix RTNL lock usage on bnxt_get_port_module_status().
  ...
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>Diffstat</a> (limited to 'net/llc')</div><table summary='diffstat' class='diffstat'>