linux/fs/9p/v9fs.c
Eric Van Hensbergen 344504e912
fs/9p: Expand setup of writeback cache to all levels
If cache is enabled, make sure we are putting the right things
in place (mainly impacts mmap).  This also sets us up for more
cache levels.

Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
2023-02-23 22:39:36 +00:00

735 lines
16 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* This file contains functions assisting in mapping VFS to 9P2000
*
* Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/parser.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "cache.h"
static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
static LIST_HEAD(v9fs_sessionlist);
struct kmem_cache *v9fs_inode_cache;
/*
* Option Parsing (code inspired by NFS code)
* NOTE: each transport will parse its own options
*/
enum {
/* Options that take integer arguments */
Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
/* String options */
Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
/* Options that take no arguments */
Opt_nodevmap,
/* Cache options */
Opt_cache_loose, Opt_fscache, Opt_mmap,
/* Access options */
Opt_access, Opt_posixacl,
/* Lock timeout option */
Opt_locktimeout,
/* Error token */
Opt_err
};
static const match_table_t tokens = {
{Opt_debug, "debug=%x"},
{Opt_dfltuid, "dfltuid=%u"},
{Opt_dfltgid, "dfltgid=%u"},
{Opt_afid, "afid=%u"},
{Opt_uname, "uname=%s"},
{Opt_remotename, "aname=%s"},
{Opt_nodevmap, "nodevmap"},
{Opt_cache, "cache=%s"},
{Opt_cache_loose, "loose"},
{Opt_fscache, "fscache"},
{Opt_mmap, "mmap"},
{Opt_cachetag, "cachetag=%s"},
{Opt_access, "access=%s"},
{Opt_posixacl, "posixacl"},
{Opt_locktimeout, "locktimeout=%u"},
{Opt_err, NULL}
};
static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
[CACHE_NONE] = "none",
[CACHE_MMAP] = "mmap",
[CACHE_LOOSE] = "loose",
[CACHE_FSCACHE] = "fscache",
};
/* Interpret mount options for cache mode */
static int get_cache_mode(char *s)
{
int version = -EINVAL;
if (!strcmp(s, "loose")) {
version = CACHE_LOOSE;
p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
} else if (!strcmp(s, "fscache")) {
version = CACHE_FSCACHE;
p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
} else if (!strcmp(s, "mmap")) {
version = CACHE_MMAP;
p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
} else if (!strcmp(s, "none")) {
version = CACHE_NONE;
p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
} else
pr_info("Unknown Cache mode %s\n", s);
return version;
}
/*
* Display the mount options in /proc/mounts.
*/
int v9fs_show_options(struct seq_file *m, struct dentry *root)
{
struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
if (v9ses->debug)
seq_printf(m, ",debug=%x", v9ses->debug);
if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
seq_printf(m, ",dfltuid=%u",
from_kuid_munged(&init_user_ns, v9ses->dfltuid));
if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
seq_printf(m, ",dfltgid=%u",
from_kgid_munged(&init_user_ns, v9ses->dfltgid));
if (v9ses->afid != ~0)
seq_printf(m, ",afid=%u", v9ses->afid);
if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
seq_printf(m, ",uname=%s", v9ses->uname);
if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
seq_printf(m, ",aname=%s", v9ses->aname);
if (v9ses->nodev)
seq_puts(m, ",nodevmap");
if (v9ses->cache)
seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
#ifdef CONFIG_9P_FSCACHE
if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
seq_printf(m, ",cachetag=%s", v9ses->cachetag);
#endif
switch (v9ses->flags & V9FS_ACCESS_MASK) {
case V9FS_ACCESS_USER:
seq_puts(m, ",access=user");
break;
case V9FS_ACCESS_ANY:
seq_puts(m, ",access=any");
break;
case V9FS_ACCESS_CLIENT:
seq_puts(m, ",access=client");
break;
case V9FS_ACCESS_SINGLE:
seq_printf(m, ",access=%u",
from_kuid_munged(&init_user_ns, v9ses->uid));
break;
}
if (v9ses->flags & V9FS_POSIX_ACL)
seq_puts(m, ",posixacl");
return p9_show_client_options(m, v9ses->clnt);
}
/**
* v9fs_parse_options - parse mount options into session structure
* @v9ses: existing v9fs session information
* @opts: The mount option string
*
* Return 0 upon success, -ERRNO upon failure.
*/
static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
{
char *options, *tmp_options;
substring_t args[MAX_OPT_ARGS];
char *p;
int option = 0;
char *s;
int ret = 0;
/* setup defaults */
v9ses->afid = ~0;
v9ses->debug = 0;
v9ses->cache = CACHE_NONE;
#ifdef CONFIG_9P_FSCACHE
v9ses->cachetag = NULL;
#endif
v9ses->session_lock_timeout = P9_LOCK_TIMEOUT;
if (!opts)
return 0;
tmp_options = kstrdup(opts, GFP_KERNEL);
if (!tmp_options) {
ret = -ENOMEM;
goto fail_option_alloc;
}
options = tmp_options;
while ((p = strsep(&options, ",")) != NULL) {
int token, r;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_debug:
r = match_int(&args[0], &option);
if (r < 0) {
p9_debug(P9_DEBUG_ERROR,
"integer field, but no integer?\n");
ret = r;
} else {
v9ses->debug = option;
#ifdef CONFIG_NET_9P_DEBUG
p9_debug_level = option;
#endif
}
break;
case Opt_dfltuid:
r = match_int(&args[0], &option);
if (r < 0) {
p9_debug(P9_DEBUG_ERROR,
"integer field, but no integer?\n");
ret = r;
continue;
}
v9ses->dfltuid = make_kuid(current_user_ns(), option);
if (!uid_valid(v9ses->dfltuid)) {
p9_debug(P9_DEBUG_ERROR,
"uid field, but not a uid?\n");
ret = -EINVAL;
}
break;
case Opt_dfltgid:
r = match_int(&args[0], &option);
if (r < 0) {
p9_debug(P9_DEBUG_ERROR,
"integer field, but no integer?\n");
ret = r;
continue;
}
v9ses->dfltgid = make_kgid(current_user_ns(), option);
if (!gid_valid(v9ses->dfltgid)) {
p9_debug(P9_DEBUG_ERROR,
"gid field, but not a gid?\n");
ret = -EINVAL;
}
break;
case Opt_afid:
r = match_int(&args[0], &option);
if (r < 0) {
p9_debug(P9_DEBUG_ERROR,
"integer field, but no integer?\n");
ret = r;
} else {
v9ses->afid = option;
}
break;
case Opt_uname:
kfree(v9ses->uname);
v9ses->uname = match_strdup(&args[0]);
if (!v9ses->uname) {
ret = -ENOMEM;
goto free_and_return;
}
break;
case Opt_remotename:
kfree(v9ses->aname);
v9ses->aname = match_strdup(&args[0]);
if (!v9ses->aname) {
ret = -ENOMEM;
goto free_and_return;
}
break;
case Opt_nodevmap:
v9ses->nodev = 1;
break;
case Opt_cache_loose:
v9ses->cache = CACHE_LOOSE;
break;
case Opt_fscache:
v9ses->cache = CACHE_FSCACHE;
break;
case Opt_mmap:
v9ses->cache = CACHE_MMAP;
break;
case Opt_cachetag:
#ifdef CONFIG_9P_FSCACHE
kfree(v9ses->cachetag);
v9ses->cachetag = match_strdup(&args[0]);
if (!v9ses->cachetag) {
ret = -ENOMEM;
goto free_and_return;
}
#endif
break;
case Opt_cache:
s = match_strdup(&args[0]);
if (!s) {
ret = -ENOMEM;
p9_debug(P9_DEBUG_ERROR,
"problem allocating copy of cache arg\n");
goto free_and_return;
}
r = get_cache_mode(s);
if (r < 0)
ret = r;
else
v9ses->cache = r;
kfree(s);
break;
case Opt_access:
s = match_strdup(&args[0]);
if (!s) {
ret = -ENOMEM;
p9_debug(P9_DEBUG_ERROR,
"problem allocating copy of access arg\n");
goto free_and_return;
}
v9ses->flags &= ~V9FS_ACCESS_MASK;
if (strcmp(s, "user") == 0)
v9ses->flags |= V9FS_ACCESS_USER;
else if (strcmp(s, "any") == 0)
v9ses->flags |= V9FS_ACCESS_ANY;
else if (strcmp(s, "client") == 0) {
v9ses->flags |= V9FS_ACCESS_CLIENT;
} else {
uid_t uid;
v9ses->flags |= V9FS_ACCESS_SINGLE;
r = kstrtouint(s, 10, &uid);
if (r) {
ret = r;
pr_info("Unknown access argument %s: %d\n",
s, r);
kfree(s);
continue;
}
v9ses->uid = make_kuid(current_user_ns(), uid);
if (!uid_valid(v9ses->uid)) {
ret = -EINVAL;
pr_info("Unknown uid %s\n", s);
}
}
kfree(s);
break;
case Opt_posixacl:
#ifdef CONFIG_9P_FS_POSIX_ACL
v9ses->flags |= V9FS_POSIX_ACL;
#else
p9_debug(P9_DEBUG_ERROR,
"Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
#endif
break;
case Opt_locktimeout:
r = match_int(&args[0], &option);
if (r < 0) {
p9_debug(P9_DEBUG_ERROR,
"integer field, but no integer?\n");
ret = r;
continue;
}
if (option < 1) {
p9_debug(P9_DEBUG_ERROR,
"locktimeout must be a greater than zero integer.\n");
ret = -EINVAL;
continue;
}
v9ses->session_lock_timeout = (long)option * HZ;
break;
default:
continue;
}
}
free_and_return:
kfree(tmp_options);
fail_option_alloc:
return ret;
}
/**
* v9fs_session_init - initialize session
* @v9ses: session information structure
* @dev_name: device being mounted
* @data: options
*
*/
struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
const char *dev_name, char *data)
{
struct p9_fid *fid;
int rc = -ENOMEM;
v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
if (!v9ses->uname)
goto err_names;
v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
if (!v9ses->aname)
goto err_names;
init_rwsem(&v9ses->rename_sem);
v9ses->uid = INVALID_UID;
v9ses->dfltuid = V9FS_DEFUID;
v9ses->dfltgid = V9FS_DEFGID;
v9ses->clnt = p9_client_create(dev_name, data);
if (IS_ERR(v9ses->clnt)) {
rc = PTR_ERR(v9ses->clnt);
p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
goto err_names;
}
v9ses->flags = V9FS_ACCESS_USER;
if (p9_is_proto_dotl(v9ses->clnt)) {
v9ses->flags = V9FS_ACCESS_CLIENT;
v9ses->flags |= V9FS_PROTO_2000L;
} else if (p9_is_proto_dotu(v9ses->clnt)) {
v9ses->flags |= V9FS_PROTO_2000U;
}
rc = v9fs_parse_options(v9ses, data);
if (rc < 0)
goto err_clnt;
v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
if (!v9fs_proto_dotl(v9ses) &&
((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
/*
* We support ACCESS_CLIENT only for dotl.
* Fall back to ACCESS_USER
*/
v9ses->flags &= ~V9FS_ACCESS_MASK;
v9ses->flags |= V9FS_ACCESS_USER;
}
/*FIXME !! */
/* for legacy mode, fall back to V9FS_ACCESS_ANY */
if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
v9ses->flags &= ~V9FS_ACCESS_MASK;
v9ses->flags |= V9FS_ACCESS_ANY;
v9ses->uid = INVALID_UID;
}
if (!v9fs_proto_dotl(v9ses) ||
!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
/*
* We support ACL checks on clinet only if the protocol is
* 9P2000.L and access is V9FS_ACCESS_CLIENT.
*/
v9ses->flags &= ~V9FS_ACL_MASK;
}
fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
v9ses->aname);
if (IS_ERR(fid)) {
rc = PTR_ERR(fid);
p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
goto err_clnt;
}
if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
fid->uid = v9ses->uid;
else
fid->uid = INVALID_UID;
#ifdef CONFIG_9P_FSCACHE
/* register the session for caching */
if (v9ses->cache == CACHE_FSCACHE) {
rc = v9fs_cache_session_get_cookie(v9ses, dev_name);
if (rc < 0)
goto err_clnt;
}
#endif
spin_lock(&v9fs_sessionlist_lock);
list_add(&v9ses->slist, &v9fs_sessionlist);
spin_unlock(&v9fs_sessionlist_lock);
return fid;
err_clnt:
#ifdef CONFIG_9P_FSCACHE
kfree(v9ses->cachetag);
#endif
p9_client_destroy(v9ses->clnt);
err_names:
kfree(v9ses->uname);
kfree(v9ses->aname);
return ERR_PTR(rc);
}
/**
* v9fs_session_close - shutdown a session
* @v9ses: session information structure
*
*/
void v9fs_session_close(struct v9fs_session_info *v9ses)
{
if (v9ses->clnt) {
p9_client_destroy(v9ses->clnt);
v9ses->clnt = NULL;
}
#ifdef CONFIG_9P_FSCACHE
fscache_relinquish_volume(v9fs_session_cache(v9ses), NULL, false);
kfree(v9ses->cachetag);
#endif
kfree(v9ses->uname);
kfree(v9ses->aname);
spin_lock(&v9fs_sessionlist_lock);
list_del(&v9ses->slist);
spin_unlock(&v9fs_sessionlist_lock);
}
/**
* v9fs_session_cancel - terminate a session
* @v9ses: session to terminate
*
* mark transport as disconnected and cancel all pending requests.
*/
void v9fs_session_cancel(struct v9fs_session_info *v9ses)
{
p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
p9_client_disconnect(v9ses->clnt);
}
/**
* v9fs_session_begin_cancel - Begin terminate of a session
* @v9ses: session to terminate
*
* After this call we don't allow any request other than clunk.
*/
void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
{
p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
p9_client_begin_disconnect(v9ses->clnt);
}
extern int v9fs_error_init(void);
static struct kobject *v9fs_kobj;
#ifdef CONFIG_9P_FSCACHE
/*
* List caches associated with a session
*/
static ssize_t caches_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
ssize_t n = 0, count = 0, limit = PAGE_SIZE;
struct v9fs_session_info *v9ses;
spin_lock(&v9fs_sessionlist_lock);
list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
if (v9ses->cachetag) {
n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
if (n < 0) {
count = n;
break;
}
count += n;
limit -= n;
}
}
spin_unlock(&v9fs_sessionlist_lock);
return count;
}
static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
#endif /* CONFIG_9P_FSCACHE */
static struct attribute *v9fs_attrs[] = {
#ifdef CONFIG_9P_FSCACHE
&v9fs_attr_cache.attr,
#endif
NULL,
};
static const struct attribute_group v9fs_attr_group = {
.attrs = v9fs_attrs,
};
/**
* v9fs_sysfs_init - Initialize the v9fs sysfs interface
*
*/
static int __init v9fs_sysfs_init(void)
{
v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
if (!v9fs_kobj)
return -ENOMEM;
if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
kobject_put(v9fs_kobj);
return -ENOMEM;
}
return 0;
}
/**
* v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
*
*/
static void v9fs_sysfs_cleanup(void)
{
sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
kobject_put(v9fs_kobj);
}
static void v9fs_inode_init_once(void *foo)
{
struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
memset(&v9inode->qid, 0, sizeof(v9inode->qid));
inode_init_once(&v9inode->netfs.inode);
}
/**
* v9fs_init_inode_cache - initialize a cache for 9P
* Returns 0 on success.
*/
static int v9fs_init_inode_cache(void)
{
v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
sizeof(struct v9fs_inode),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD|SLAB_ACCOUNT),
v9fs_inode_init_once);
if (!v9fs_inode_cache)
return -ENOMEM;
return 0;
}
/**
* v9fs_destroy_inode_cache - destroy the cache of 9P inode
*
*/
static void v9fs_destroy_inode_cache(void)
{
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(v9fs_inode_cache);
}
static int v9fs_cache_register(void)
{
int ret;
ret = v9fs_init_inode_cache();
if (ret < 0)
return ret;
return ret;
}
static void v9fs_cache_unregister(void)
{
v9fs_destroy_inode_cache();
}
/**
* init_v9fs - Initialize module
*
*/
static int __init init_v9fs(void)
{
int err;
pr_info("Installing v9fs 9p2000 file system support\n");
/* TODO: Setup list of registered trasnport modules */
err = v9fs_cache_register();
if (err < 0) {
pr_err("Failed to register v9fs for caching\n");
return err;
}
err = v9fs_sysfs_init();
if (err < 0) {
pr_err("Failed to register with sysfs\n");
goto out_cache;
}
err = register_filesystem(&v9fs_fs_type);
if (err < 0) {
pr_err("Failed to register filesystem\n");
goto out_sysfs_cleanup;
}
return 0;
out_sysfs_cleanup:
v9fs_sysfs_cleanup();
out_cache:
v9fs_cache_unregister();
return err;
}
/**
* exit_v9fs - shutdown module
*
*/
static void __exit exit_v9fs(void)
{
v9fs_sysfs_cleanup();
v9fs_cache_unregister();
unregister_filesystem(&v9fs_fs_type);
}
module_init(init_v9fs)
module_exit(exit_v9fs)
MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
MODULE_LICENSE("GPL");