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// SPDX-License-Identifier: GPL-2.0-only
/*
* This file contians vfs dentry ops for the 9P2000 protocol.
*
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/namei.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
/**
* v9fs_ndentry_is_expired - Check if negative dentry lookup has expired
*
* This should be called to know if a negative dentry should be removed from
* cache.
*
* @dentry: dentry in question
*
*/
static bool v9fs_ndentry_is_expired(struct dentry const *dentry)
{
struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry);
if (v9ses->ndentry_timeout_ms == NDENTRY_TIMEOUT_NEVER)
return false;
return time_before_eq64(v9fs_dentry->expire_time, get_jiffies_64());
}
/**
* v9fs_ndentry_refresh_timeout - Refresh negative dentry lookup cache timeout
*
* This should be called when a look up yields a negative entry.
*
* @dentry: dentry in question
*
*/
void v9fs_ndentry_refresh_timeout(struct dentry *dentry)
{
struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry);
if (v9ses->ndentry_timeout_ms == NDENTRY_TIMEOUT_NEVER)
return;
v9fs_dentry->expire_time = get_jiffies_64() +
msecs_to_jiffies(v9ses->ndentry_timeout_ms);
}
/**
* v9fs_cached_dentry_delete - called when dentry refcount equals 0
* @dentry: dentry in question
*
*/
static int v9fs_cached_dentry_delete(const struct dentry *dentry)
{
p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
dentry, dentry);
if (!d_really_is_negative(dentry))
return 0;
return v9fs_ndentry_is_expired(dentry);
}
static void __v9fs_dentry_fid_remove(struct dentry *dentry)
{
struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry);
struct hlist_node *p, *n;
struct hlist_head head;
p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
dentry, dentry);
spin_lock(&dentry->d_lock);
hlist_move_list(&v9fs_dentry->head, &head);
spin_unlock(&dentry->d_lock);
hlist_for_each_safe(p, n, &head)
p9_fid_put(hlist_entry(p, struct p9_fid, dlist));
}
/**
* v9fs_dentry_fid_remove - Release all dentry's fids
* @dentry: dentry in question
*
*/
void v9fs_dentry_fid_remove(struct dentry *dentry)
{
__v9fs_dentry_fid_remove(dentry);
}
/**
* v9fs_dentry_init - Initialize v9fs dentry data
* @dentry: dentry in question
*
*/
static int v9fs_dentry_init(struct dentry *dentry)
{
struct v9fs_dentry *v9fs_dentry = kzalloc(sizeof(*v9fs_dentry),
GFP_KERNEL);
if (!v9fs_dentry)
return -ENOMEM;
INIT_HLIST_HEAD(&v9fs_dentry->head);
dentry->d_fsdata = (void *)v9fs_dentry;
return 0;
}
/**
* v9fs_dentry_release - called when dentry is going to be freed
* @dentry: dentry that is being released
*
*/
static void v9fs_dentry_release(struct dentry *dentry)
{
struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry);
__v9fs_dentry_fid_remove(dentry);
kfree_rcu(v9fs_dentry, rcu);
}
static int __v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
{
struct p9_fid *fid;
struct inode *inode;
struct v9fs_inode *v9inode;
if (flags & LOOKUP_RCU)
return -ECHILD;
inode = d_inode(dentry);
if (!inode)
return !v9fs_ndentry_is_expired(dentry);
v9inode = V9FS_I(inode);
if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
int retval;
struct v9fs_session_info *v9ses;
fid = v9fs_fid_lookup(dentry);
if (IS_ERR(fid)) {
p9_debug(
P9_DEBUG_VFS,
"v9fs_fid_lookup: dentry = %pd (%p), got error %pe\n",
dentry, dentry, fid);
return PTR_ERR(fid);
}
v9ses = v9fs_inode2v9ses(inode);
if (v9fs_proto_dotl(v9ses))
retval = v9fs_refresh_inode_dotl(fid, inode);
else
retval = v9fs_refresh_inode(fid, inode);
p9_fid_put(fid);
if (retval == -ENOENT) {
p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) invalidated due to ENOENT\n",
dentry, dentry);
return 0;
}
if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) invalidated due to type change\n",
dentry, dentry);
return 0;
}
if (retval < 0) {
p9_debug(P9_DEBUG_VFS,
"refresh inode: dentry = %pd (%p), got error %pe\n",
dentry, dentry, ERR_PTR(retval));
return retval;
}
}
p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) is valid\n", dentry, dentry);
return 1;
}
static int v9fs_lookup_revalidate(struct inode *dir, const struct qstr *name,
struct dentry *dentry, unsigned int flags)
{
return __v9fs_lookup_revalidate(dentry, flags);
}
static bool v9fs_dentry_unalias_trylock(const struct dentry *dentry)
{
struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
return down_write_trylock(&v9ses->rename_sem);
}
static void v9fs_dentry_unalias_unlock(const struct dentry *dentry)
{
struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
up_write(&v9ses->rename_sem);
}
const struct dentry_operations v9fs_cached_dentry_operations = {
.d_revalidate = v9fs_lookup_revalidate,
.d_weak_revalidate = __v9fs_lookup_revalidate,
.d_delete = v9fs_cached_dentry_delete,
.d_init = v9fs_dentry_init,
.d_release = v9fs_dentry_release,
.d_unalias_trylock = v9fs_dentry_unalias_trylock,
.d_unalias_unlock = v9fs_dentry_unalias_unlock,
};
const struct dentry_operations v9fs_dentry_operations = {
.d_init = v9fs_dentry_init,
.d_release = v9fs_dentry_release,
.d_unalias_trylock = v9fs_dentry_unalias_trylock,
.d_unalias_unlock = v9fs_dentry_unalias_unlock,
};
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