/*
* Open file cache.
*
* (c) 2015 - Jeff Layton <jeff.layton@primarydata.com>
*/
#include <linux/hash.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/sched.h>
#include <linux/list_lru.h>
#include <linux/fsnotify_backend.h>
#include <linux/fsnotify.h>
#include <linux/seq_file.h>
#include "vfs.h"
#include "nfsd.h"
#include "nfsfh.h"
#include "netns.h"
#include "filecache.h"
#include "trace.h"
#define NFSDDBG_FACILITY NFSDDBG_FH
/* FIXME: dynamically size this for the machine somehow? */
#define NFSD_FILE_HASH_BITS 12
#define NFSD_FILE_HASH_SIZE (1 << NFSD_FILE_HASH_BITS)
#define NFSD_LAUNDRETTE_DELAY (2 * HZ)
#define NFSD_FILE_SHUTDOWN (1)
#define NFSD_FILE_LRU_THRESHOLD (4096UL)
#define NFSD_FILE_LRU_LIMIT (NFSD_FILE_LRU_THRESHOLD << 2)
/* We only care about NFSD_MAY_READ/WRITE for this cache */
#define NFSD_FILE_MAY_MASK (NFSD_MAY_READ|NFSD_MAY_WRITE)
struct nfsd_fcache_bucket {
struct hlist_head nfb_head;
spinlock_t nfb_lock;
unsigned int nfb_count;
unsigned int nfb_maxcount;
};
static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits);
struct nfsd_fcache_disposal {
struct list_head list;
struct work_struct work;
struct net *net;
spinlock_t lock;
struct list_head freeme;
struct rcu_head rcu;
};
static struct workqueue_struct *nfsd_filecache_wq __read_mostly;
static struct kmem_cache *nfsd_file_slab;
static struct kmem_cache *nfsd_file_mark_slab;
static struct nfsd_fcache_bucket *nfsd_file_hashtbl;
static struct list_lru nfsd_file_lru;
static long nfsd_file_lru_flags;
static struct fsnotify_group *nfsd_file_fsnotify_group;
static atomic_long_t nfsd_filecache_count;
static struct delayed_work nfsd_filecache_laundrette;
static DEFINE_SPINLOCK(laundrette_lock);
static LIST_HEAD(laundrettes);
static void nfsd_file_gc(void);
static void
nfsd_file_schedule_laundrette(void)
{
long count = atomic_long_read(&nfsd_filecache_count);
if (count == 0 || test_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags))
return;
queue_delayed_work(system_wq, &nfsd_filecache_laundrette,
NFSD_LAUNDRETTE_DELAY);
}
static void
nfsd_file_slab_free(struct rcu_head *rcu)
{
struct nfsd_file *nf = container_of(rcu, struct nfsd_file, nf_rcu);
put_cred(nf->nf_cred);
kmem_cache_free(nfsd_file_slab, nf);
}
static void
nfsd_file_mark_free(struct fsnotify_mark *mark)
{
struct nfsd_file_mark *nfm = container_of(mark, struct nfsd_file_mark,
nfm_mark);
kmem_cache_free(nfsd_file_mark_slab, nfm);
}
static struct nfsd_file_mark *
nfsd_file_mark_get(struct nfsd_file_mark *nfm)
{
if (!refcount_inc_not_zero(&nfm->nfm_ref))
return NULL;
return nfm;
}
static void
nfsd_file_mark_put(struct nfsd_file_mark *nfm)
{
if (refcount_dec_and_test(&nfm->nfm_ref)) {
fsnotify_destroy_mark(&nfm->nfm_mark, nfsd_file_fsnotify_group);
fsnotify_put_mark(&nfm->nfm_mark);
}
}
static struct nfsd_file_mark *
nfsd_file_mark_find_or_create(struct nfsd_file *nf)
{
int err;
struct fsnotify_mark *mark;
struct nfsd_file_mark *nfm = NULL, *new;
struct inode *inode = nf->nf_inode;
do {
mutex_lock(&nfsd_file_fsnotify_group->mark_mutex);
mark = fsnotify_find_mark(&inode->i_fsnotify_marks,
nfsd_file_fsnotify_group);
if (mark) {
nfm = nfsd_file_mark_get(container_of(mark,
struct nfsd_file_mark,
nfm_mark));
mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex);
if (nfm) {
fsnotify_put_mark(mark);
break;
}
/* Avoid soft lockup race with nfsd_file_mark_put() */
fsnotify_destroy_mark(mark, nfsd_file_fsnotify_group);
fsnotify_put_mark(mark);
} else
mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex);
/* allocate a new nfm */
new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL);
if (!new)
return NULL;
fsnotify_init_mark(&ne