[linux-block.git] / fs / afs / dynroot.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* AFS dynamic root handling
 *
 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/dns_resolver.h>
#include "internal.h"

static atomic_t afs_autocell_ino;

/*
 * iget5() comparator for inode created by autocell operations
 *
 * These pseudo inodes don't match anything.
 */
static int afs_iget5_pseudo_test(struct inode *inode, void *opaque)
{
	return 0;
}

/*
 * iget5() inode initialiser
 */
static int afs_iget5_pseudo_set(struct inode *inode, void *opaque)
{
	struct afs_super_info *as = AFS_FS_S(inode->i_sb);
	struct afs_vnode *vnode = AFS_FS_I(inode);
	struct afs_fid *fid = opaque;

	vnode->volume		= as->volume;
	vnode->fid		= *fid;
	inode->i_ino		= fid->vnode;
	inode->i_generation	= fid->unique;
	return 0;
}

/*
 * Create an inode for a dynamic root directory or an autocell dynamic
 * automount dir.
 */
struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
{
	struct afs_super_info *as = AFS_FS_S(sb);
	struct afs_vnode *vnode;
	struct inode *inode;
	struct afs_fid fid = {};

	_enter("");

	if (as->volume)
		fid.vid = as->volume->vid;
	if (root) {
		fid.vnode = 1;
		fid.unique = 1;
	} else {
		fid.vnode = atomic_inc_return(&afs_autocell_ino);
		fid.unique = 0;
	}

	inode = iget5_locked(sb, fid.vnode,
			     afs_iget5_pseudo_test, afs_iget5_pseudo_set, &fid);
	if (!inode) {
		_leave(" = -ENOMEM");
		return ERR_PTR(-ENOMEM);
	}

	_debug("GOT INODE %p { ino=%lu, vl=%llx, vn=%llx, u=%x }",
	       inode, inode->i_ino, fid.vid, fid.vnode, fid.unique);

	vnode = AFS_FS_I(inode);

	/* there shouldn't be an existing inode */
	BUG_ON(!(inode->i_state & I_NEW));

	netfs_inode_init(&vnode->netfs, NULL);
	inode->i_size		= 0;
	inode->i_mode		= S_IFDIR | S_IRUGO | S_IXUGO;
	if (root) {
		inode->i_op	= &afs_dynroot_inode_operations;
		inode->i_fop	= &simple_dir_operations;
	} else {
		inode->i_op	= &afs_autocell_inode_operations;
	}
	set_nlink(inode, 2);
	inode->i_uid		= GLOBAL_ROOT_UID;
	inode->i_gid		= GLOBAL_ROOT_GID;
	simple_inode_init_ts(inode);
	inode->i_blocks		= 0;
	inode->i_generation	= 0;

	set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
	if (!root) {
		set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
		inode->i_flags |= S_AUTOMOUNT;
	}

	inode->i_flags |= S_NOATIME;
	unlock_new_inode(inode);
	_leave(" = %p", inode);
	return inode;
}

/*
 * Probe to see if a cell may exist.  This prevents positive dentries from
 * being created unnecessarily.
 */
static int afs_probe_cell_name(struct dentry *dentry)
{
	struct afs_cell *cell;
	struct afs_net *net = afs_d2net(dentry);
	const char *name = dentry->d_name.name;
	size_t len = dentry->d_name.len;
	char *result = NULL;
	int ret;

	/* Names prefixed with a dot are R/W mounts. */
	if (name[0] == '.') {
		if (len == 1)
			return -EINVAL;
		name++;
		len--;
	}

	cell = afs_find_cell(net, name, len, afs_cell_trace_use_probe);
	if (!IS_ERR(cell)) {
		afs_unuse_cell(net, cell, afs_cell_trace_unuse_probe);
		return 0;
	}

	ret = dns_query(net->net, "afsdb", name, len, "srv=1",
			&result, NULL, false);
	if (ret == -ENODATA || ret == -ENOKEY || ret == 0)
		ret = -ENOENT;
	if (ret > 0 && ret >= sizeof(struct dns_server_list_v1_header)) {
		struct dns_server_list_v1_header *v1 = (void *)result;

		if (v1->hdr.zero == 0 &&
		    v1->hdr.content == DNS_PAYLOAD_IS_SERVER_LIST &&
		    v1->hdr.version == 1 &&
		    (v1->status != DNS_LOOKUP_GOOD &&
		     v1->status != DNS_LOOKUP_GOOD_WITH_BAD))
			return -ENOENT;

	}

	kfree(result);
	return ret;
}

/*
 * Try to auto mount the mountpoint with pseudo directory, if the autocell
 * operation is setted.
 */
struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir)
{
	struct afs_vnode *vnode = AFS_FS_I(dir);
	struct inode *inode;
	int ret = -ENOENT;

	_enter("%p{%pd}, {%llx:%llu}",
	       dentry, dentry, vnode->fid.vid, vnode->fid.vnode);

	if (!test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
		goto out;

	ret = afs_probe_cell_name(dentry);
	if (ret < 0)
		goto out;

	inode = afs_iget_pseudo_dir(dir->i_sb, false);
	if (IS_ERR(inode)) {
		ret = PTR_ERR(inode);
		goto out;
	}

	_leave("= %p", inode);
	return inode;

out:
	_leave("= %d", ret);
	return ret == -ENOENT ? NULL : ERR_PTR(ret);
}

/*
 * Look up @cell in a dynroot directory.  This is a substitution for the
 * local cell name for the net namespace.
 */
static struct dentry *afs_lookup_atcell(struct dentry *dentry)
{
	struct afs_cell *cell;
	struct afs_net *net = afs_d2net(dentry);
	struct dentry *ret;
	char *name;
	int len;

	if (!net->ws_cell)
		return ERR_PTR(-ENOENT);

	ret = ERR_PTR(-ENOMEM);
	name = kmalloc(AFS_MAXCELLNAME + 1, GFP_KERNEL);
	if (!name)
		goto out_p;

	down_read(&net->cells_lock);
	cell = net->ws_cell;
	if (cell) {
		len = cell->name_len;
		memcpy(name, cell->name, len + 1);
	}
	up_read(&net->cells_lock);

	ret = ERR_PTR(-ENOENT);
	if (!cell)
		goto out_n;

	ret = lookup_one_len(name, dentry->d_parent, len);

	/* We don't want to d_add() the @cell dentry here as we don't want to
	 * the cached dentry to hide changes to the local cell name.
	 */

out_n:
	kfree(name);
out_p:
	return ret;
}

/*
 * Look up an entry in a dynroot directory.
 */
static struct dentry *afs_dynroot_lookup(struct inode *dir, struct dentry *dentry,
					 unsigned int flags)
{
	_enter("%pd", dentry);

	ASSERTCMP(d_inode(dentry), ==, NULL);

	if (flags & LOOKUP_CREATE)
		return ERR_PTR(-EOPNOTSUPP);

	if (dentry->d_name.len >= AFSNAMEMAX) {
		_leave(" = -ENAMETOOLONG");
		return ERR_PTR(-ENAMETOOLONG);
	}

	if (dentry->d_name.len == 5 &&
	    memcmp(dentry->d_name.name, "@cell", 5) == 0)
		return afs_lookup_atcell(dentry);

	return d_splice_alias(afs_try_auto_mntpt(dentry, dir), dentry);
}

const struct inode_operations afs_dynroot_inode_operations = {
	.lookup		= afs_dynroot_lookup,
};

/*
 * Dirs in the dynamic root don't need revalidation.
 */
static int afs_dynroot_d_revalidate(struct dentry *dentry, unsigned int flags)
{
	return 1;
}

const struct dentry_operations afs_dynroot_dentry_operations = {
	.d_revalidate	= afs_dynroot_d_revalidate,
	.d_delete	= always_delete_dentry,
	.d_release	= afs_d_release,
	.d_automount	= afs_d_automount,
};

/*
 * Create a manually added cell mount directory.
 * - The caller must hold net->proc_cells_lock
 */
int afs_dynroot_mkdir(struct afs_net *net, struct afs_cell *cell)
{
	struct super_block *sb = net->dynroot_sb;
	struct dentry *root, *subdir;
	int ret;

	if (!sb || atomic_read(&sb->s_active) == 0)
		return 0;

	/* Let the ->lookup op do the creation */
	root = sb->s_root;
	inode_lock(root->d_inode);
	subdir = lookup_one_len(cell->name, root, cell->name_len);
	if (IS_ERR(subdir)) {
		ret = PTR_ERR(subdir);
		goto unlock;
	}

	/* Note that we're retaining an extra ref on the dentry */
	subdir->d_fsdata = (void *)1UL;
	ret = 0;
unlock:
	inode_unlock(root->d_inode);
	return ret;
}

/*
 * Remove a manually added cell mount directory.
 * - The caller must hold net->proc_cells_lock
 */
void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell)
{
	struct super_block *sb = net->dynroot_sb;
	struct dentry *root, *subdir;

	if (!sb || atomic_read(&sb->s_active) == 0)
		return;

	root = sb->s_root;
	inode_lock(root->d_inode);

	/* Don't want to trigger a lookup call, which will re-add the cell */
	subdir = try_lookup_one_len(cell->name, root, cell->name_len);
	if (IS_ERR_OR_NULL(subdir)) {
		_debug("lookup %ld", PTR_ERR(subdir));
		goto no_dentry;
	}

	_debug("rmdir %pd %u", subdir, d_count(subdir));

	if (subdir->d_fsdata) {
		_debug("unpin %u", d_count(subdir));
		subdir->d_fsdata = NULL;
		dput(subdir);
	}
	dput(subdir);
no_dentry:
	inode_unlock(root->d_inode);
	_leave("");
}

/*
 * Populate a newly created dynamic root with cell names.
 */
int afs_dynroot_populate(struct super_block *sb)
{
	struct afs_cell *cell;
	struct afs_net *net = afs_sb2net(sb);
	int ret;

	mutex_lock(&net->proc_cells_lock);

	net->dynroot_sb = sb;
	hlist_for_each_entry(cell, &net->proc_cells, proc_link) {
		ret = afs_dynroot_mkdir(net, cell);
		if (ret < 0)
			goto error;
	}

	ret = 0;
out:
	mutex_unlock(&net->proc_cells_lock);
	return ret;

error:
	net->dynroot_sb = NULL;
	goto out;
}

/*
 * When a dynamic root that's in the process of being destroyed, depopulate it
 * of pinned directories.
 */
void afs_dynroot_depopulate(struct super_block *sb)
{
	struct afs_net *net = afs_sb2net(sb);
	struct dentry *root = sb->s_root, *subdir;

	/* Prevent more subdirs from being created */
	mutex_lock(&net->proc_cells_lock);
	if (net->dynroot_sb == sb)
		net->dynroot_sb = NULL;
	mutex_unlock(&net->proc_cells_lock);

	if (root) {
		struct hlist_node *n;
		inode_lock(root->d_inode);

		/* Remove all the pins for dirs created for manually added cells */
		hlist_for_each_entry_safe(subdir, n, &root->d_children, d_sib) {
			if (subdir->d_fsdata) {
				subdir->d_fsdata = NULL;
				dput(subdir);
			}
		}

		inode_unlock(root->d_inode);
	}
}
Commit	Line	Data
b4d0d230	1	// SPDX-License-Identifier: GPL-2.0-or-later
0da0b7fd	2	/* AFS dynamic root handling
66c7e1d3 DH	3	*
	4	* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
66c7e1d3 DH	6	*/
	7
	8	#include <linux/fs.h>
	9	#include <linux/namei.h>
	10	#include <linux/dns_resolver.h>
	11	#include "internal.h"
	12
e49c7b2f DH	13	static atomic_t afs_autocell_ino;
	14
	15	/*
	16	* iget5() comparator for inode created by autocell operations
	17	*
	18	* These pseudo inodes don't match anything.
	19	*/
	20	static int afs_iget5_pseudo_test(struct inode inode, void opaque)
	21	{
	22	return 0;
	23	}
	24
	25	/*
	26	* iget5() inode initialiser
	27	*/
	28	static int afs_iget5_pseudo_set(struct inode inode, void opaque)
	29	{
	30	struct afs_super_info *as = AFS_FS_S(inode->i_sb);
	31	struct afs_vnode *vnode = AFS_FS_I(inode);
	32	struct afs_fid *fid = opaque;
	33
	34	vnode->volume = as->volume;
	35	vnode->fid = *fid;
	36	inode->i_ino = fid->vnode;
	37	inode->i_generation = fid->unique;
	38	return 0;
	39	}
	40
	41	/*
	42	* Create an inode for a dynamic root directory or an autocell dynamic
	43	* automount dir.
	44	*/
	45	struct inode afs_iget_pseudo_dir(struct super_block sb, bool root)
	46	{
	47	struct afs_super_info *as = AFS_FS_S(sb);
	48	struct afs_vnode *vnode;
	49	struct inode *inode;
	50	struct afs_fid fid = {};
	51
	52	_enter("");
	53
	54	if (as->volume)
	55	fid.vid = as->volume->vid;
	56	if (root) {
	57	fid.vnode = 1;
	58	fid.unique = 1;
	59	} else {
	60	fid.vnode = atomic_inc_return(&afs_autocell_ino);
	61	fid.unique = 0;
	62	}
	63
	64	inode = iget5_locked(sb, fid.vnode,
	65	afs_iget5_pseudo_test, afs_iget5_pseudo_set, &fid);
	66	if (!inode) {
	67	_leave(" = -ENOMEM");
	68	return ERR_PTR(-ENOMEM);
	69	}
	70
	71	_debug("GOT INODE %p { ino=%lu, vl=%llx, vn=%llx, u=%x }",
	72	inode, inode->i_ino, fid.vid, fid.vnode, fid.unique);
	73
	74	vnode = AFS_FS_I(inode);
	75
	76	/* there shouldn't be an existing inode */
77	BUG_ON(!(inode->i_state & I_NEW));
78
e81fb419	79	netfs_inode_init(&vnode->netfs, NULL);
e49c7b2f DH	80	inode->i_size = 0;
	81	inode->i_mode = S_IFDIR \| S_IRUGO \| S_IXUGO;
	82	if (root) {
	83	inode->i_op = &afs_dynroot_inode_operations;
	84	inode->i_fop = &simple_dir_operations;
	85	} else {
	86	inode->i_op = &afs_autocell_inode_operations;
	87	}
	88	set_nlink(inode, 2);
	89	inode->i_uid = GLOBAL_ROOT_UID;
	90	inode->i_gid = GLOBAL_ROOT_GID;
562ce1f7	91	simple_inode_init_ts(inode);
e49c7b2f DH	92	inode->i_blocks = 0;
	93	inode->i_generation = 0;
	94
	95	set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
	96	if (!root) {
	97	set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
	98	inode->i_flags \|= S_AUTOMOUNT;
	99	}
	100
	101	inode->i_flags \|= S_NOATIME;
	102	unlock_new_inode(inode);
	103	_leave(" = %p", inode);
	104	return inode;
	105	}
	106
66c7e1d3 DH	107	/*
	108	* Probe to see if a cell may exist. This prevents positive dentries from
	109	* being created unnecessarily.
	110	*/
	111	static int afs_probe_cell_name(struct dentry *dentry)
	112	{
	113	struct afs_cell *cell;
a58946c1	114	struct afs_net *net = afs_d2net(dentry);
66c7e1d3 DH	115	const char *name = dentry->d_name.name;
66c7e1d3 DH	116	size_t len = dentry->d_name.len;
74cef687	117	char *result = NULL;
66c7e1d3 DH	118	int ret;
	119
	120	/* Names prefixed with a dot are R/W mounts. */
	121	if (name[0] == '.') {
	122	if (len == 1)
	123	return -EINVAL;
	124	name++;
	125	len--;
	126	}
	127
dca54a7b	128	cell = afs_find_cell(net, name, len, afs_cell_trace_use_probe);
66c7e1d3	129	if (!IS_ERR(cell)) {
dca54a7b	130	afs_unuse_cell(net, cell, afs_cell_trace_unuse_probe);
66c7e1d3 DH	131	return 0;
	132	}
	133
a58946c1	134	ret = dns_query(net->net, "afsdb", name, len, "srv=1",
74cef687 DH	135	&result, NULL, false);
74cef687 DH	136	if (ret == -ENODATA \|\| ret == -ENOKEY \|\| ret == 0)
2a4ca1b4	137	ret = -ENOENT;
74cef687 DH	138	if (ret > 0 && ret >= sizeof(struct dns_server_list_v1_header)) {
	139	struct dns_server_list_v1_header v1 = (void )result;
	140
	141	if (v1->hdr.zero == 0 &&
	142	v1->hdr.content == DNS_PAYLOAD_IS_SERVER_LIST &&
	143	v1->hdr.version == 1 &&
	144	(v1->status != DNS_LOOKUP_GOOD &&
	145	v1->status != DNS_LOOKUP_GOOD_WITH_BAD))
	146	return -ENOENT;
	147
	148	}
	149
	150	kfree(result);
66c7e1d3 DH	151	return ret;
	152	}
	153
	154	/*
	155	* Try to auto mount the mountpoint with pseudo directory, if the autocell
	156	* operation is setted.
	157	*/
	158	struct inode afs_try_auto_mntpt(struct dentry dentry, struct inode *dir)
	159	{
	160	struct afs_vnode *vnode = AFS_FS_I(dir);
	161	struct inode *inode;
	162	int ret = -ENOENT;
	163
3b6492df	164	_enter("%p{%pd}, {%llx:%llu}",
66c7e1d3 DH	165	dentry, dentry, vnode->fid.vid, vnode->fid.vnode);
	166
	167	if (!test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
	168	goto out;
	169
	170	ret = afs_probe_cell_name(dentry);
	171	if (ret < 0)
	172	goto out;
	173
	174	inode = afs_iget_pseudo_dir(dir->i_sb, false);
	175	if (IS_ERR(inode)) {
	176	ret = PTR_ERR(inode);
	177	goto out;
	178	}
	179
	180	_leave("= %p", inode);
	181	return inode;
	182
	183	out:
	184	_leave("= %d", ret);
1401a0fc	185	return ret == -ENOENT ? NULL : ERR_PTR(ret);
66c7e1d3 DH	186	}
	187
	188	/*
	189	* Look up @cell in a dynroot directory. This is a substitution for the
	190	* local cell name for the net namespace.
	191	*/
	192	static struct dentry afs_lookup_atcell(struct dentry dentry)
	193	{
	194	struct afs_cell *cell;
	195	struct afs_net *net = afs_d2net(dentry);
	196	struct dentry *ret;
66c7e1d3 DH	197	char *name;
	198	int len;
	199
	200	if (!net->ws_cell)
	201	return ERR_PTR(-ENOENT);
	202
	203	ret = ERR_PTR(-ENOMEM);
	204	name = kmalloc(AFS_MAXCELLNAME + 1, GFP_KERNEL);
	205	if (!name)
	206	goto out_p;
	207
92e3cc91 DH	208	down_read(&net->cells_lock);
	209	cell = net->ws_cell;
	210	if (cell) {
	211	len = cell->name_len;
	212	memcpy(name, cell->name, len + 1);
	213	}
	214	up_read(&net->cells_lock);
66c7e1d3 DH	215
	216	ret = ERR_PTR(-ENOENT);
	217	if (!cell)
	218	goto out_n;
	219
	220	ret = lookup_one_len(name, dentry->d_parent, len);
	221
	222	/* We don't want to d_add() the @cell dentry here as we don't want to
	223	* the cached dentry to hide changes to the local cell name.
	224	*/
	225
	226	out_n:
	227	kfree(name);
	228	out_p:
	229	return ret;
	230	}
	231
	232	/*
	233	* Look up an entry in a dynroot directory.
	234	*/
	235	static struct dentry afs_dynroot_lookup(struct inode dir, struct dentry *dentry,
	236	unsigned int flags)
	237	{
66c7e1d3 DH	238	_enter("%pd", dentry);
	239
	240	ASSERTCMP(d_inode(dentry), ==, NULL);
	241
1da4bd9f DH	242	if (flags & LOOKUP_CREATE)
	243	return ERR_PTR(-EOPNOTSUPP);
	244
66c7e1d3 DH	245	if (dentry->d_name.len >= AFSNAMEMAX) {
	246	_leave(" = -ENAMETOOLONG");
	247	return ERR_PTR(-ENAMETOOLONG);
	248	}
	249
	250	if (dentry->d_name.len == 5 &&
	251	memcmp(dentry->d_name.name, "@cell", 5) == 0)
	252	return afs_lookup_atcell(dentry);
	253
1401a0fc	254	return d_splice_alias(afs_try_auto_mntpt(dentry, dir), dentry);
66c7e1d3 DH	255	}
	256
	257	const struct inode_operations afs_dynroot_inode_operations = {
	258	.lookup = afs_dynroot_lookup,
	259	};
	260
	261	/*
	262	* Dirs in the dynamic root don't need revalidation.
	263	*/
	264	static int afs_dynroot_d_revalidate(struct dentry *dentry, unsigned int flags)
	265	{
	266	return 1;
	267	}
	268
66c7e1d3 DH	269	const struct dentry_operations afs_dynroot_dentry_operations = {
66c7e1d3 DH	270	.d_revalidate = afs_dynroot_d_revalidate,
71f8b55b	271	.d_delete = always_delete_dentry,
66c7e1d3 DH	272	.d_release = afs_d_release,
	273	.d_automount = afs_d_automount,
	274	};
0da0b7fd DH	275
	276	/*
	277	* Create a manually added cell mount directory.
	278	* - The caller must hold net->proc_cells_lock
	279	*/
	280	int afs_dynroot_mkdir(struct afs_net net, struct afs_cell cell)
	281	{
	282	struct super_block *sb = net->dynroot_sb;
	283	struct dentry root, subdir;
	284	int ret;
	285
	286	if (!sb \|\| atomic_read(&sb->s_active) == 0)
	287	return 0;
	288
	289	/* Let the ->lookup op do the creation */
	290	root = sb->s_root;
	291	inode_lock(root->d_inode);
	292	subdir = lookup_one_len(cell->name, root, cell->name_len);
	293	if (IS_ERR(subdir)) {
	294	ret = PTR_ERR(subdir);
	295	goto unlock;
	296	}
	297
	298	/* Note that we're retaining an extra ref on the dentry */
	299	subdir->d_fsdata = (void *)1UL;
	300	ret = 0;
	301	unlock:
	302	inode_unlock(root->d_inode);
	303	return ret;
	304	}
	305
	306	/*
	307	* Remove a manually added cell mount directory.
	308	* - The caller must hold net->proc_cells_lock
	309	*/
	310	void afs_dynroot_rmdir(struct afs_net net, struct afs_cell cell)
	311	{
	312	struct super_block *sb = net->dynroot_sb;
	313	struct dentry root, subdir;
	314
	315	if (!sb \|\| atomic_read(&sb->s_active) == 0)
	316	return;
	317
	318	root = sb->s_root;
	319	inode_lock(root->d_inode);
	320
	321	/* Don't want to trigger a lookup call, which will re-add the cell */
	322	subdir = try_lookup_one_len(cell->name, root, cell->name_len);
	323	if (IS_ERR_OR_NULL(subdir)) {
	324	_debug("lookup %ld", PTR_ERR(subdir));
	325	goto no_dentry;
	326	}
	327
	328	_debug("rmdir %pd %u", subdir, d_count(subdir));
	329
	330	if (subdir->d_fsdata) {
	331	_debug("unpin %u", d_count(subdir));
	332	subdir->d_fsdata = NULL;
	333	dput(subdir);
	334	}
	335	dput(subdir);
	336	no_dentry:
	337	inode_unlock(root->d_inode);
	338	_leave("");
339	}
340
341	/*
342	* Populate a newly created dynamic root with cell names.
343	*/
344	int afs_dynroot_populate(struct super_block *sb)
345	{
346	struct afs_cell *cell;
347	struct afs_net *net = afs_sb2net(sb);
348	int ret;
349
3b05e528	350	mutex_lock(&net->proc_cells_lock);
0da0b7fd DH	351
0da0b7fd DH	352	net->dynroot_sb = sb;
6b3944e4	353	hlist_for_each_entry(cell, &net->proc_cells, proc_link) {
0da0b7fd DH	354	ret = afs_dynroot_mkdir(net, cell);
	355	if (ret < 0)
	356	goto error;
	357	}
	358
	359	ret = 0;
	360	out:
	361	mutex_unlock(&net->proc_cells_lock);
	362	return ret;
	363
	364	error:
	365	net->dynroot_sb = NULL;
	366	goto out;
	367	}
	368
	369	/*
	370	* When a dynamic root that's in the process of being destroyed, depopulate it
	371	* of pinned directories.
	372	*/
	373	void afs_dynroot_depopulate(struct super_block *sb)
	374	{
	375	struct afs_net *net = afs_sb2net(sb);
da549bdd	376	struct dentry root = sb->s_root, subdir;
0da0b7fd DH	377
	378	/* Prevent more subdirs from being created */
	379	mutex_lock(&net->proc_cells_lock);
	380	if (net->dynroot_sb == sb)
	381	net->dynroot_sb = NULL;
	382	mutex_unlock(&net->proc_cells_lock);
	383
5e0b17b0	384	if (root) {
da549bdd	385	struct hlist_node *n;
5e0b17b0 DH	386	inode_lock(root->d_inode);
	387
	388	/* Remove all the pins for dirs created for manually added cells */
da549bdd	389	hlist_for_each_entry_safe(subdir, n, &root->d_children, d_sib) {
5e0b17b0 DH	390	if (subdir->d_fsdata) {
	391	subdir->d_fsdata = NULL;
	392	dput(subdir);
	393	}
0da0b7fd	394	}
0da0b7fd	395
5e0b17b0 DH	396	inode_unlock(root->d_inode);
5e0b17b0 DH	397	}
0da0b7fd	398	}