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linux-stable/fs/9p/v9fs.c
David Howells bc899ee1c8 netfs: Add a netfs inode context 
Add a netfs_i_context struct that should be included in the network
filesystem's own inode struct wrapper, directly after the VFS's inode
struct, e.g.:

	struct my_inode {
		struct {
			/* These must be contiguous */
			struct inode		vfs_inode;
			struct netfs_i_context	netfs_ctx;
		};
	};

The netfs_i_context struct so far contains a single field for the network
filesystem to use - the cache cookie:

	struct netfs_i_context {
		...
		struct fscache_cookie	*cache;
	};

Three functions are provided to help with this:

 (1) void netfs_i_context_init(struct inode *inode,
			       const struct netfs_request_ops *ops);

     Initialise the netfs context and set the operations.

 (2) struct netfs_i_context *netfs_i_context(struct inode *inode);

     Find the netfs context from the VFS inode.

 (3) struct inode *netfs_inode(struct netfs_i_context *ctx);

     Find the VFS inode from the netfs context.

Changes
=======
ver #4)
 - Fix netfs_is_cache_enabled() to check cookie->cache_priv to see if a
   cache is present[3].
 - Fix netfs_skip_folio_read() to zero out all of the page, not just some
   of it[3].

ver #3)
 - Split out the bit to move ceph cap-getting on readahead into
   ceph_init_request()[1].
 - Stick in a comment to the netfs inode structs indicating the contiguity
   requirements[2].

ver #2)
 - Adjust documentation to match.
 - Use "#if IS_ENABLED()" in netfs_i_cookie(), not "#ifdef".
 - Move the cap check from ceph_readahead() to ceph_init_request() to be
   called from netfslib.
 - Remove ceph_readahead() and use  netfs_readahead() directly instead.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com

Link: https://lore.kernel.org/r/8af0d47f17d89c06bbf602496dd845f2b0bf25b3.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/beaf4f6a6c2575ed489adb14b257253c868f9a5c.camel@kernel.org/ [2]
Link: https://lore.kernel.org/r/3536452.1647421585@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/164622984545.3564931.15691742939278418580.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/164678213320.1200972.16807551936267647470.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692909854.2099075.9535537286264248057.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/306388.1647595110@warthog.procyon.org.uk/ # v4
2022-03-18 09:29:05 +00:00

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// 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/idr.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_LOOSE || 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->vfs_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");
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