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/*
Caching file system proxy
Copyright (C) 2004 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
*/
#define FUSE_USE_VERSION 22
#include "cache.h"
#include <stdio.h>
#include <errno.h>
#include <glib.h>
#include <pthread.h>
#define CACHE_TIMEOUT 20
#define MAX_CACHE_SIZE 10000
#define CACHE_CLEAN_INTERVAL 60
struct node_attr {
struct stat stat;
time_t stat_valid;
time_t valid;
};
struct fuse_cache_dirhandle {
const char *path;
fuse_dirh_t h;
fuse_dirfil_t filler;
};
static struct fuse_cache_operations *next_oper;
static GHashTable *cache;
static pthread_mutex_t cache_lock;
static time_t last_cleaned;
static int cache_clean_entry(void *_key, struct node_attr *node, time_t *now)
{
(void) _key;
if (*now > node->valid)
return TRUE;
else
return FALSE;
}
static void cache_clean(void)
{
time_t now = time(NULL);
if (g_hash_table_size(cache) > MAX_CACHE_SIZE ||
now > last_cleaned + CACHE_CLEAN_INTERVAL) {
g_hash_table_foreach_remove(cache, (GHRFunc) cache_clean_entry, &now);
last_cleaned = now;
}
}
static struct node_attr *cache_lookup(const char *path)
{
return (struct node_attr *) g_hash_table_lookup(cache, path);
}
static void cache_remove(const char *path)
{
pthread_mutex_lock(&cache_lock);
g_hash_table_remove(cache, path);
pthread_mutex_unlock(&cache_lock);
}
static void cache_invalidate(const char *path)
{
cache_remove(path);
}
static void cache_do_rename(const char *from, const char *to)
{
cache_remove(from);
cache_remove(to);
}
static struct node_attr *cache_get(const char *path)
{
struct node_attr *node = cache_lookup(path);
if (node == NULL) {
char *pathcopy = g_strdup(path);
node = g_new0(struct node_attr, 1);
g_hash_table_insert(cache, pathcopy, node);
}
return node;
}
static void cache_add_attr(const char *path, const struct stat *stbuf)
{
struct node_attr *node;
time_t now;
pthread_mutex_lock(&cache_lock);
node = cache_get(path);
now = time(NULL);
node->stat = *stbuf;
node->stat_valid = time(NULL) + CACHE_TIMEOUT;
if (node->stat_valid > node->valid)
node->valid = node->stat_valid;
cache_clean();
pthread_mutex_unlock(&cache_lock);
}
static int cache_getattr(const char *path, struct stat *stbuf)
{
struct node_attr *node;
int err;
pthread_mutex_lock(&cache_lock);
node = cache_lookup(path);
if (node != NULL) {
time_t now = time(NULL);
if (node->valid - now >= 0) {
*stbuf = node->stat;
pthread_mutex_unlock(&cache_lock);
return 0;
}
}
pthread_mutex_unlock(&cache_lock);
err = next_oper->oper.getattr(path, stbuf);
if (!err)
cache_add_attr(path, stbuf);
return err;
}
static int cache_dirfill(fuse_cache_dirh_t ch, const char *name,
const struct stat *stbuf)
{
int err = ch->filler(ch->h, name, 0, 0);
if (!err) {
char *fullpath = g_strdup_printf("%s/%s",
!ch->path[1] ? "" : ch->path, name);
cache_add_attr(fullpath, stbuf);
g_free(fullpath);
}
return err;
}
static int cache_getdir(const char *path, fuse_dirh_t h, fuse_dirfil_t filler)
{
struct fuse_cache_dirhandle ch;
ch.path = path;
ch.h = h;
ch.filler = filler;
return next_oper->cache_getdir(path, &ch, cache_dirfill);
}
static int cache_unlink(const char *path)
{
int err = next_oper->oper.unlink(path);
if (!err)
cache_remove(path);
return err;
}
static int cache_rmdir(const char *path)
{
int err = next_oper->oper.rmdir(path);
if (!err)
cache_remove(path);
return err;
}
static int cache_rename(const char *from, const char *to)
{
int err = next_oper->oper.rename(from, to);
if (!err)
cache_do_rename(from, to);
return err;
}
static int cache_chmod(const char *path, mode_t mode)
{
int err = next_oper->oper.chmod(path, mode);
if (!err)
cache_invalidate(path);
return err;
}
static int cache_chown(const char *path, uid_t uid, gid_t gid)
{
int err = next_oper->oper.chown(path, uid, gid);
if (!err)
cache_invalidate(path);
return err;
}
static int cache_truncate(const char *path, off_t size)
{
int err = next_oper->oper.truncate(path, size);
if (!err)
cache_invalidate(path);
return err;
}
static int cache_utime(const char *path, struct utimbuf *buf)
{
int err = next_oper->oper.utime(path, buf);
if (!err)
cache_invalidate(path);
return err;
}
struct fuse_operations *cache_init(struct fuse_cache_operations *oper)
{
static struct fuse_operations cache_oper;
next_oper = oper;
cache_oper.getattr = oper->oper.getattr ? cache_getattr : NULL;
cache_oper.readlink = oper->oper.readlink;
cache_oper.getdir = oper->cache_getdir ? cache_getdir : oper->oper.getdir;
cache_oper.mknod = oper->oper.mknod;
cache_oper.mkdir = oper->oper.mkdir;
cache_oper.symlink = oper->oper.symlink;
cache_oper.unlink = oper->oper.unlink ? cache_unlink : NULL;
cache_oper.rmdir = oper->oper.rmdir ? cache_rmdir : NULL;
cache_oper.rename = oper->oper.rename ? cache_rename : NULL;
cache_oper.link = oper->oper.link;
cache_oper.chmod = oper->oper.chmod ? cache_chmod : NULL;
cache_oper.chown = oper->oper.chown ? cache_chown : NULL;
cache_oper.truncate = oper->oper.truncate ? cache_truncate : NULL;
cache_oper.utime = oper->oper.utime ? cache_utime : NULL;
cache_oper.open = oper->oper.open;
cache_oper.read = oper->oper.read;
cache_oper.write = oper->oper.write;
cache_oper.statfs = oper->oper.statfs;
cache_oper.release = oper->oper.release;
cache_oper.fsync = oper->oper.fsync;
cache_oper.setxattr = oper->oper.setxattr;
cache_oper.getxattr = oper->oper.getxattr;
cache_oper.listxattr = oper->oper.listxattr;
cache_oper.removexattr = oper->oper.removexattr;
pthread_mutex_init(&cache_lock, NULL);
cache = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, g_free);
if (cache == NULL) {
fprintf(stderr, "failed to create cache\n");
return NULL;
}
return &cache_oper;
}
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