/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2005 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
*/
#include "fuse_i.h"
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/gfp.h>
#include <linux/sched.h>
#include <linux/namei.h>
/*
* FUSE caches dentries and attributes with separate timeout. The
* time in jiffies until the dentry/attributes are valid is stored in
* dentry->d_time and fuse_inode->i_time respectively.
*/
/*
* Calculate the time in jiffies until a dentry/attributes are valid
*/
static unsigned long time_to_jiffies(unsigned long sec, unsigned long nsec)
{
struct timespec ts = {sec, nsec};
return jiffies + timespec_to_jiffies(&ts);
}
/*
* Set dentry and possibly attribute timeouts from the lookup/mk*
* replies
*/
static void fuse_change_timeout(struct dentry *entry, struct fuse_entry_out *o)
{
entry->d_time = time_to_jiffies(o->entry_valid, o->entry_valid_nsec);
if (entry->d_inode)
get_fuse_inode(entry->d_inode)->i_time =
time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
}
/*
* Mark the attributes as stale, so that at the next call to
* ->getattr() they will be fetched from userspace
*/
void fuse_invalidate_attr(struct inode *inode)
{
get_fuse_inode(inode)->i_time = jiffies - 1;
}
/*
* Just mark the entry as stale, so that a next attempt to look it up
* will result in a new lookup call to userspace
*
* This is called when a dentry is about to become negative and the
* timeout is unknown (unlink, rmdir, rename and in some cases
* lookup)
*/
static void fuse_invalidate_entry_cache(struct dentry *entry)
{
entry->d_time = jiffies - 1;
}
/*
* Same as fuse_invalidate_entry_cache(), but also try to remove the
* dentry from the hash
*/
static void fuse_invalidate_entry(struct dentry *entry)
{
d_invalidate(entry);
fuse_invalidate_entry_cache(entry);
}
static void fuse_lookup_init(struct fuse_req *req, struct inode *dir,
struct dentry *entry,
struct fuse_entry_out *outarg)
{
req->in.h.opcode = FUSE_LOOKUP;
req->in.h.nodeid = get_node_id(dir);
req->inode = dir;
req->in.numargs = 1;
req->in.args[0].size = entry->d_name.len + 1;
req->in.args[0].value = entry->d_name.name;
req->out.numargs = 1;
req->out.args[0].size = sizeof(struct fuse_entry_out);
req->out.args[0].value = outarg;
}
/*
* Check whether the dentry is still valid
*
* If the entry validity timeout has expired and the dentry is
* positive, try to redo the lookup. If the lookup results in a
* different inode, then let the VFS invalidate the dentry and redo
* the lookup once more. If the lookup results in the same inode,
* then refresh the attributes, timeouts and mark the dentry valid.
*/
static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
{
struct inode *inode = entry->d_inode;
if (inode && is_bad_inode(inode))
return 0;
else if (time_after(jiffies, entry->d_time)) {
int err;
struct fuse_entry_out