diff options
Diffstat (limited to 'fs/nfsd/filecache.c')
| -rw-r--r-- | fs/nfsd/filecache.c | 950 |
1 files changed, 542 insertions, 408 deletions
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index fdf89fcf1a0c..ec3fceb92236 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -7,11 +7,13 @@ #include <linux/hash.h> #include <linux/slab.h> #include <linux/file.h> +#include <linux/pagemap.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 <linux/rhashtable.h> #include "vfs.h" #include "nfsd.h" @@ -20,59 +22,170 @@ #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) +#define NFSD_FILE_CACHE_UP (0) /* 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); +static DEFINE_PER_CPU(unsigned long, nfsd_file_acquisitions); +static DEFINE_PER_CPU(unsigned long, nfsd_file_releases); +static DEFINE_PER_CPU(unsigned long, nfsd_file_total_age); +static DEFINE_PER_CPU(unsigned long, nfsd_file_pages_flushed); +static DEFINE_PER_CPU(unsigned long, nfsd_file_evictions); 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 unsigned long nfsd_file_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 struct rhashtable nfsd_file_rhash_tbl + ____cacheline_aligned_in_smp; + +enum nfsd_file_lookup_type { + NFSD_FILE_KEY_INODE, + NFSD_FILE_KEY_FULL, +}; + +struct nfsd_file_lookup_key { + struct inode *inode; + struct net *net; + const struct cred *cred; + unsigned char need; + enum nfsd_file_lookup_type type; +}; + +/* + * The returned hash value is based solely on the address of an in-code + * inode, a pointer to a slab-allocated object. The entropy in such a + * pointer is concentrated in its middle bits. + */ +static u32 nfsd_file_inode_hash(const struct inode *inode, u32 seed) +{ + unsigned long ptr = (unsigned long)inode; + u32 k; + + k = ptr >> L1_CACHE_SHIFT; + k &= 0x00ffffff; + return jhash2(&k, 1, seed); +} + +/** + * nfsd_file_key_hashfn - Compute the hash value of a lookup key + * @data: key on which to compute the hash value + * @len: rhash table's key_len parameter (unused) + * @seed: rhash table's random seed of the day + * + * Return value: + * Computed 32-bit hash value + */ +static u32 nfsd_file_key_hashfn(const void *data, u32 len, u32 seed) +{ + const struct nfsd_file_lookup_key *key = data; + + return nfsd_file_inode_hash(key->inode, seed); +} + +/** + * nfsd_file_obj_hashfn - Compute the hash value of an nfsd_file + * @data: object on which to compute the hash value + * @len: rhash table's key_len parameter (unused) + * @seed: rhash table's random seed of the day + * + * Return value: + * Computed 32-bit hash value + */ +static u32 nfsd_file_obj_hashfn(const void *data, u32 len, u32 seed) +{ + const struct nfsd_file *nf = data; + + return nfsd_file_inode_hash(nf->nf_inode, seed); +} + +static bool +nfsd_match_cred(const struct cred *c1, const struct cred *c2) +{ + int i; + + if (!uid_eq(c1->fsuid, c2->fsuid)) + return false; + if (!gid_eq(c1->fsgid, c2->fsgid)) + return false; + if (c1->group_info == NULL || c2->group_info == NULL) + return c1->group_info == c2->group_info; + if (c1->group_info->ngroups != c2->group_info->ngroups) + return false; + for (i = 0; i < c1->group_info->ngroups; i++) { + if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i])) + return false; + } + return true; +} -static void nfsd_file_gc(void); +/** + * nfsd_file_obj_cmpfn - Match a cache item against search criteria + * @arg: search criteria + * @ptr: cache item to check + * + * Return values: + * %0 - Item matches search criteria + * %1 - Item does not match search criteria + */ +static int nfsd_file_obj_cmpfn(struct rhashtable_compare_arg *arg, + const void *ptr) +{ + const struct nfsd_file_lookup_key *key = arg->key; + const struct nfsd_file *nf = ptr; + + switch (key->type) { + case NFSD_FILE_KEY_INODE: + if (nf->nf_inode != key->inode) + return 1; + break; + case NFSD_FILE_KEY_FULL: + if (nf->nf_inode != key->inode) + return 1; + if (nf->nf_may != key->need) + return 1; + if (nf->nf_net != key->net) + return 1; + if (!nfsd_match_cred(nf->nf_cred, key->cred)) + return 1; + if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0) + return 1; + break; + } + return 0; +} + +static const struct rhashtable_params nfsd_file_rhash_params = { + .key_len = sizeof_field(struct nfsd_file, nf_inode), + .key_offset = offsetof(struct nfsd_file, nf_inode), + .head_offset = offsetof(struct nfsd_file, nf_rhash), + .hashfn = nfsd_file_key_hashfn, + .obj_hashfn = nfsd_file_obj_hashfn, + .obj_cmpfn = nfsd_file_obj_cmpfn, + /* Reduce resizing churn on light workloads */ + .min_size = 512, /* buckets */ + .automatic_shrinking = true, +}; 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)) + if ((atomic_read(&nfsd_file_rhash_tbl.nelems) == 0) || + test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 0) return; queue_delayed_work(system_wq, &nfsd_filecache_laundrette, @@ -115,22 +228,21 @@ nfsd_file_mark_put(struct nfsd_file_mark *nfm) } static struct nfsd_file_mark * -nfsd_file_mark_find_or_create(struct nfsd_file *nf) +nfsd_file_mark_find_or_create(struct nfsd_file *nf, struct inode *inode) { 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); + fsnotify_group_lock(nfsd_file_fsnotify_group); mark = fsnotify_find_mark(&inode->i_fsnotify_marks, - nfsd_file_fsnotify_group); + 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); + fsnotify_group_unlock(nfsd_file_fsnotify_group); if (nfm) { fsnotify_put_mark(mark); break; @@ -138,8 +250,9 @@ nfsd_file_mark_find_or_create(struct nfsd_file *nf) /* 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); + } else { + fsnotify_group_unlock(nfsd_file_fsnotify_group); + } /* allocate a new nfm */ new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL); @@ -170,32 +283,25 @@ nfsd_file_mark_find_or_create(struct nfsd_file *nf) } static struct nfsd_file * -nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval, - struct net *net) +nfsd_file_alloc(struct nfsd_file_lookup_key *key, unsigned int may) { struct nfsd_file *nf; nf = kmem_cache_alloc(nfsd_file_slab, GFP_KERNEL); if (nf) { - INIT_HLIST_NODE(&nf->nf_node); INIT_LIST_HEAD(&nf->nf_lru); + nf->nf_birthtime = ktime_get(); nf->nf_file = NULL; nf->nf_cred = get_current_cred(); - nf->nf_net = net; + nf->nf_net = key->net; nf->nf_flags = 0; - nf->nf_inode = inode; - nf->nf_hashval = hashval; - refcount_set(&nf->nf_ref, 1); - nf->nf_may = may & NFSD_FILE_MAY_MASK; - if (may & NFSD_MAY_NOT_BREAK_LEASE) { - if (may & NFSD_MAY_WRITE) - __set_bit(NFSD_FILE_BREAK_WRITE, &nf->nf_flags); - if (may & NFSD_MAY_READ) - __set_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags); - } + __set_bit(NFSD_FILE_HASHED, &nf->nf_flags); + __set_bit(NFSD_FILE_PENDING, &nf->nf_flags); + nf->nf_inode = key->inode; + /* nf_ref is pre-incremented for hash table */ + refcount_set(&nf->nf_ref, 2); + nf->nf_may = key->need; nf->nf_mark = NULL; - init_rwsem(&nf->nf_rwsem); - trace_nfsd_file_alloc(nf); } return nf; } @@ -203,8 +309,12 @@ nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval, static bool nfsd_file_free(struct nfsd_file *nf) { + s64 age = ktime_to_ms(ktime_sub(ktime_get(), nf->nf_birthtime)); bool flush = false; + this_cpu_inc(nfsd_file_releases); + this_cpu_add(nfsd_file_total_age, age); + trace_nfsd_file_put_final(nf); if (nf->nf_mark) nfsd_file_mark_put(nf->nf_mark); @@ -214,6 +324,14 @@ nfsd_file_free(struct nfsd_file *nf) fput(nf->nf_file); flush = true; } + + /* + * If this item is still linked via nf_lru, that's a bug. + * WARN and leak it to preserve system stability. + */ + if (WARN_ON_ONCE(!list_empty(&nf->nf_lru))) + return flush; + call_rcu(&nf->nf_rcu, nfsd_file_slab_free); return flush; } @@ -242,48 +360,60 @@ nfsd_file_check_write_error(struct nfsd_file *nf) } static void -nfsd_file_do_unhash(struct nfsd_file *nf) +nfsd_file_flush(struct nfsd_file *nf) +{ + struct file *file = nf->nf_file; + + if (!file || !(file->f_mode & FMODE_WRITE)) + return; + this_cpu_add(nfsd_file_pages_flushed, file->f_mapping->nrpages); + if (vfs_fsync(file, 1) != 0) + nfsd_reset_write_verifier(net_generic(nf->nf_net, nfsd_net_id)); +} + +static void nfsd_file_lru_add(struct nfsd_file *nf) { - lockdep_assert_held(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock); + set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags); + if (list_lru_add(&nfsd_file_lru, &nf->nf_lru)) + trace_nfsd_file_lru_add(nf); +} +static void nfsd_file_lru_remove(struct nfsd_file *nf) +{ + if (list_lru_del(&nfsd_file_lru, &nf->nf_lru)) + trace_nfsd_file_lru_del(nf); +} + +static void +nfsd_file_hash_remove(struct nfsd_file *nf) +{ trace_nfsd_file_unhash(nf); if (nfsd_file_check_write_error(nf)) - nfsd_reset_boot_verifier(net_generic(nf->nf_net, nfsd_net_id)); - --nfsd_file_hashtbl[nf->nf_hashval].nfb_count; - hlist_del_rcu(&nf->nf_node); - atomic_long_dec(&nfsd_filecache_count); + nfsd_reset_write_verifier(net_generic(nf->nf_net, nfsd_net_id)); + rhashtable_remove_fast(&nfsd_file_rhash_tbl, &nf->nf_rhash, + nfsd_file_rhash_params); } static bool nfsd_file_unhash(struct nfsd_file *nf) { if (test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { - nfsd_file_do_unhash(nf); - if (!list_empty(&nf->nf_lru)) - list_lru_del(&nfsd_file_lru, &nf->nf_lru); + nfsd_file_hash_remove(nf); return true; } return false; } -/* - * Return true if the file was unhashed. - */ -static bool -nfsd_file_unhash_and_release_locked(struct nfsd_file *nf, struct list_head *dispose) +static void +nfsd_file_unhash_and_dispose(struct nfsd_file *nf, struct list_head *dispose) { - lockdep_assert_held(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock); - - trace_nfsd_file_unhash_and_release_locked(nf); - if (!nfsd_file_unhash(nf)) - return false; - /* keep final reference for nfsd_file_lru_dispose */ - if (refcount_dec_not_one(&nf->nf_ref)) - return true; - - list_add(&nf->nf_lru, dispose); - return true; + trace_nfsd_file_unhash_and_dispose(nf); + if (nfsd_file_unhash(nf)) { + /* caller must call nfsd_file_dispose_list() later */ + nfsd_file_lru_remove(nf); + list_add(&nf->nf_lru, dispose); + } } static void @@ -293,6 +423,7 @@ nfsd_file_put_noref(struct nfsd_file *nf) if (refcount_dec_and_test(&nf->nf_ref)) { WARN_ON(test_bit(NFSD_FILE_HASHED, &nf->nf_flags)); + nfsd_file_lru_remove(nf); nfsd_file_free(nf); } } @@ -300,21 +431,35 @@ nfsd_file_put_noref(struct nfsd_file *nf) void nfsd_file_put(struct nfsd_file *nf) { - bool is_hashed; + might_sleep(); - set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags); - if (refcount_read(&nf->nf_ref) > 2 || !nf->nf_file) { + nfsd_file_lru_add(nf); + if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0) { + nfsd_file_flush(nf); + nfsd_file_put_noref(nf); + } else if (nf->nf_file) { nfsd_file_put_noref(nf); - return; - } - - filemap_flush(nf->nf_file->f_mapping); - is_hashed = test_bit(NFSD_FILE_HASHED, &nf->nf_flags) != 0; - nfsd_file_put_noref(nf); - if (is_hashed) nfsd_file_schedule_laundrette(); - if (atomic_long_read(&nfsd_filecache_count) >= NFSD_FILE_LRU_LIMIT) - nfsd_file_gc(); + } else + nfsd_file_put_noref(nf); +} + +/** + * nfsd_file_close - Close an nfsd_file + * @nf: nfsd_file to close + * + * If this is the final reference for @nf, free it immediately. + * This reflects an on-the-wire CLOSE or DELEGRETURN into the + * VFS and exported filesystem. + */ +void nfsd_file_close(struct nfsd_file *nf) +{ + nfsd_file_put(nf); + if (refcount_dec_if_one(&nf->nf_ref)) { + nfsd_file_unhash(nf); + nfsd_file_lru_remove(nf); + nfsd_file_free(nf); + } } struct nfsd_file * @@ -332,7 +477,8 @@ nfsd_file_dispose_list(struct list_head *dispose) while(!list_empty(dispose)) { nf = list_first_entry(dispose, struct nfsd_file, nf_lru); - list_del(&nf->nf_lru); + list_del_init(&nf->nf_lru); + nfsd_file_flush(nf); nfsd_file_put_noref(nf); } } @@ -345,7 +491,8 @@ nfsd_file_dispose_list_sync(struct list_head *dispose) while(!list_empty(dispose)) { nf = list_first_entry(dispose, struct nfsd_file, nf_lru); - list_del(&nf->nf_lru); + list_del_init(&nf->nf_lru); + nfsd_file_flush(nf); if (!refcount_dec_and_test(&nf->nf_ref)) continue; if (nfsd_file_free(nf)) @@ -367,19 +514,13 @@ nfsd_file_list_remove_disposal(struct list_head *dst, static void nfsd_file_list_add_disposal(struct list_head *files, struct net *net) { - struct nfsd_fcache_disposal *l; + struct nfsd_net *nn = net_generic(net, nfsd_net_id); + struct nfsd_fcache_disposal *l = nn->fcache_disposal; - rcu_read_lock(); - list_for_each_entry_rcu(l, &laundrettes, list) { - if (l->net == net) { - spin_lock(&l->lock); - list_splice_tail_init(files, &l->freeme); - spin_unlock(&l->lock); - queue_work(nfsd_filecache_wq, &l->work); - break; - } - } - rcu_read_unlock(); + spin_lock(&l->lock); + list_splice_tail_init(files, &l->freeme); + spin_unlock(&l->lock); + queue_work(nfsd_filecache_wq, &l->work); } static void @@ -407,8 +548,17 @@ nfsd_file_dispose_list_delayed(struct list_head *dispose) } } -/* - * Note this can deadlock with nfsd_file_cache_purge. +/** + * nfsd_file_lru_cb - Examine an entry on the LRU list + * @item: LRU entry to examine + * @lru: controlling LRU + * @lock: LRU list lock (unused) + * @arg: dispose list + * + * Return values: + * %LRU_REMOVED: @item was removed from the LRU + * %LRU_ROTATE: @item is to be moved to the LRU tail + * %LRU_SKIP: @item cannot be evicted */ static enum lru_status nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru, @@ -429,55 +579,65 @@ nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru, * counter. Here we check the counter and then test and clear the flag. * That order is deliberate to ensure that we can do this locklessly. */ - if (refcount_read(&nf->nf_ref) > 1) - goto out_skip; + if (refcount_read(&nf->nf_ref) > 1) { + list_lru_isolate(lru, &nf->nf_lru); + trace_nfsd_file_gc_in_use(nf); + return LRU_REMOVED; + } /* * Don't throw out files that are still undergoing I/O or * that have uncleared errors pending. */ - if (nfsd_file_check_writeback(nf)) - goto out_skip; + if (nfsd_file_check_writeback(nf)) { + trace_nfsd_file_gc_writeback(nf); + return LRU_SKIP; + } - if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags)) - goto out_skip; + if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags)) { + trace_nfsd_file_gc_referenced(nf); + return LRU_ROTATE; + } - if (!test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) - goto out_skip; + if (!test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { + trace_nfsd_file_gc_hashed(nf); + return LRU_SKIP; + } list_lru_isolate_move(lru, &nf->nf_lru, head); + this_cpu_inc(nfsd_file_evictions); + trace_nfsd_file_gc_disposed(nf); return LRU_REMOVED; -out_skip: - return LRU_SKIP; } -static unsigned long -nfsd_file_lru_walk_list(struct shrink_control *sc) +/* + * Unhash items on @dispose immediately, then queue them on the + * disposal workqueue to finish releasing them in the background. + * + * cel: Note that between the time list_lru_shrink_walk runs and + * now, these items are in the hash table but marked unhashed. + * Why release these outside of lru_cb ? There's no lock ordering + * problem since lru_cb currently takes no lock. + */ +static void nfsd_file_gc_dispose_list(struct list_head *dispose) { - LIST_HEAD(head); struct nfsd_file *nf; - unsigned long ret; - if (sc) - ret = list_lru_shrink_walk(&nfsd_file_lru, sc, - nfsd_file_lru_cb, &head); - else - ret = list_lru_walk(&nfsd_file_lru, - nfsd_file_lru_cb, - &head, LONG_MAX); - list_for_each_entry(nf, &head, nf_lru) { - spin_lock(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock); - nfsd_file_do_unhash(nf); - spin_unlock(&nfsd_file_hashtbl[nf->nf_hashval].nfb_lock); - } - nfsd_file_dispose_list_delayed(&head); - return ret; + list_for_each_entry(nf, dispose, nf_lru) + nfsd_file_hash_remove(nf); + nfsd_file_dispose_list_delayed(dispose); } static void nfsd_file_gc(void) { - nfsd_file_lru_walk_list(NULL); + LIST_HEAD(dispose); + unsigned long ret; + + ret = list_lru_walk(&nfsd_file_lru, nfsd_file_lru_cb, + &dispose, list_lru_count(&nfsd_file_lru)); + trace_nfsd_file_gc_removed(ret, list_lru_count(&nfsd_file_lru)); + nfsd_file_gc_dispose_list(&dispose); } static void @@ -496,7 +656,14 @@ nfsd_file_lru_count(struct shrinker *s, struct shrink_control *sc) static unsigned long nfsd_file_lru_scan(struct shrinker *s, struct shrink_control *sc) { - return nfsd_file_lru_walk_list(sc); + LIST_HEAD(dispose); + unsigned long ret; + + ret = list_lru_shrink_walk(&nfsd_file_lru, sc, + nfsd_file_lru_cb, &dispose); + trace_nfsd_file_shrinker_removed(ret, list_lru_count(&nfsd_file_lru)); + nfsd_file_gc_dispose_list(&dispose); + return ret; } static struct shrinker nfsd_file_shrinker = { @@ -505,39 +672,47 @@ static struct shrinker nfsd_file_shrinker = { .seeks = 1, }; -static void -__nfsd_file_close_inode(struct inode *inode, unsigned int hashval, - struct list_head *dispose) +/* + * Find all cache items across all net namespaces that match @inode and + * move them to @dispose. The lookup is atomic wrt nfsd_file_acquire(). + */ +static unsigned int +__nfsd_file_close_inode(struct inode *inode, struct list_head *dispose) { - struct nfsd_file *nf; - struct hlist_node *tmp; + struct nfsd_file_lookup_key key = { + .type = NFSD_FILE_KEY_INODE, + .inode = inode, + }; + unsigned int count = 0; + struct nfsd_file *nf; - spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock); - hlist_for_each_entry_safe(nf, tmp, &nfsd_file_hashtbl[hashval].nfb_head, nf_node) { - if (inode == nf->nf_inode) - nfsd_file_unhash_and_release_locked(nf, dispose); - } - spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock); + rcu_read_lock(); + do { + nf = rhashtable_lookup(&nfsd_file_rhash_tbl, &key, + nfsd_file_rhash_params); + if (!nf) + break; + nfsd_file_unhash_and_dispose(nf, dispose); + count++; + } while (1); + rcu_read_unlock(); + return count; } /** * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file * @inode: inode of the file to attempt to remove * - * Walk the whole hash bucket, looking for any files that correspond to "inode". - * If any do, then unhash them and put the hashtable reference to them and - * destroy any that had their last reference put. Also ensure that any of the - * fputs also have their final __fput done as well. + * Unhash and put, then flush and fput all cache items associated with @inode. */ void nfsd_file_close_inode_sync(struct inode *inode) { - unsigned int hashval = (unsigned int)hash_long(inode->i_ino, - NFSD_FILE_HASH_BITS); LIST_HEAD(dispose); + unsigned int count; - __nfsd_file_close_inode(inode, hashval, &dispose); - trace_nfsd_file_close_inode_sync(inode, hashval, !list_empty(&dispose)); + count = __nfsd_file_close_inode(inode, &dispose); + trace_nfsd_file_close_inode_sync(inode, count); nfsd_file_dispose_list_sync(&dispose); } @@ -545,19 +720,16 @@ nfsd_file_close_inode_sync(struct inode *inode) * nfsd_file_close_inode - attempt a delayed close of a nfsd_file * @inode: inode of the file to attempt to remove * - * Walk the whole hash bucket, looking for any files that correspond to "inode". - * If any do, then unhash them and put the hashtable reference to them and - * destroy any that had their last reference put. + * Unhash and put all cache item associated with @inode. */ static void nfsd_file_close_inode(struct inode *inode) { - unsigned int hashval = (unsigned int)hash_long(inode->i_ino, - NFSD_FILE_HASH_BITS); LIST_HEAD(dispose); + unsigned int count; - __nfsd_file_close_inode(inode, hashval, &dispose); - trace_nfsd_file_close_inode(inode, hashval, !list_empty(&dispose)); + count = __nfsd_file_close_inode(inode, &dispose); + trace_nfsd_file_close_inode(inode, count); nfsd_file_dispose_list_delayed(&dispose); } @@ -567,8 +739,6 @@ nfsd_file_close_inode(struct inode *inode) * * Walk the LRU list and close any entries that have not been used since * the last scan. - * - * Note this can deadlock with nfsd_file_cache_purge. */ static void nfsd_file_delayed_close(struct work_struct *work) @@ -632,25 +802,21 @@ static const struct fsnotify_ops nfsd_file_fsnotify_ops = { int nfsd_file_cache_init(void) { - int ret = -ENOMEM; - unsigned int i; + int ret; - clear_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags); - - if (nfsd_file_hashtbl) + lockdep_assert_held(&nfsd_mutex); + if (test_and_set_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1) return 0; + ret = rhashtable_init(&nfsd_file_rhash_tbl, &nfsd_file_rhash_params); + if (ret) + return ret; + + ret = -ENOMEM; nfsd_filecache_wq = alloc_workqueue("nfsd_filecache", 0, 0); if (!nfsd_filecache_wq) goto out; - nfsd_file_hashtbl = kcalloc(NFSD_FILE_HASH_SIZE, - sizeof(*nfsd_file_hashtbl), GFP_KERNEL); - if (!nfsd_file_hashtbl) { - pr_err("nfsd: unable to allocate nfsd_file_hashtbl\n"); - goto out_err; - } - nfsd_file_slab = kmem_cache_create("nfsd_file", sizeof(struct nfsd_file), 0, 0, NULL); if (!nfsd_file_slab) { @@ -672,7 +838,7 @@ nfsd_file_cache_init(void) goto out_err; } - ret = register_shrinker(&nfsd_file_shrinker); + ret = register_shrinker(&nfsd_file_shrinker, "nfsd-filecache"); if (ret) { pr_err("nfsd: failed to register nfsd_file_shrinker: %d\n", ret); goto out_lru; @@ -684,7 +850,8 @@ nfsd_file_cache_init(void) goto out_shrinker; } - nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops); + nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops, + FSNOTIFY_GROUP_NOFS); if (IS_ERR(nfsd_file_fsnotify_group)) { pr_err("nfsd: unable to create fsnotify group: %ld\n", PTR_ERR(nfsd_file_fsnotify_group)); @@ -693,11 +860,6 @@ nfsd_file_cache_init(void) goto out_notifier; } - for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) { - INIT_HLIST_HEAD(&nfsd_file_hashtbl[i].nfb_head); - spin_lock_init(&nfsd_file_hashtbl[i].nfb_lock); - } - INIT_DELAYED_WORK(&nfsd_filecache_laundrette, nfsd_file_gc_worker); out: return ret; @@ -712,50 +874,39 @@ out_err: nfsd_file_slab = NULL; kmem_cache_destroy(nfsd_file_mark_slab); nfsd_file_mark_slab = NULL; - kfree(nfsd_file_hashtbl); - nfsd_file_hashtbl = NULL; destroy_workqueue(nfsd_filecache_wq); nfsd_filecache_wq = NULL; + rhashtable_destroy(&nfsd_file_rhash_tbl); goto out; } -/* - * Note this can deadlock with nfsd_file_lru_cb. - */ -void -nfsd_file_cache_purge(struct net *net) +static void +__nfsd_file_cache_purge(struct net *net) { - unsigned int i; - struct nfsd_file *nf; - struct hlist_node *next; + struct rhashtable_iter iter; + struct nfsd_file *nf; LIST_HEAD(dispose); - bool del; - if (!nfsd_file_hashtbl) - return; + rhashtable_walk_enter(&nfsd_file_rhash_tbl, &iter); + do { + rhashtable_walk_start(&iter); - for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) { - struct nfsd_fcache_bucket *nfb = &nfsd_file_hashtbl[i]; + nf = rhashtable_walk_next(&iter); + while (!IS_ERR_OR_NULL(nf)) { + if (!net || nf->nf_net == net) + nfsd_file_unhash_and_dispose(nf, &dispose); + nf = rhashtable_walk_next(&iter); + } - spin_lock(&nfb->nfb_lock); - hlist_for_each_entry_safe(nf, next, &nfb->nfb_head, nf_node) { - if (net && nf->nf_net != net) - continue; - del = nfsd_file_unhash_and_release_locked(nf, &dispose); + rhashtable_walk_stop(&iter); + } while (nf == ERR_PTR(-EAGAIN)); + rhashtable_walk_exit(&iter); - /* - * Deadlock detected! Something marked this entry as - * unhased, but hasn't removed it from the hash list. - */ - WARN_ON_ONCE(!del); - } - spin_unlock(&nfb->nfb_lock); - nfsd_file_dispose_list(&dispose); - } + nfsd_file_dispose_list(&dispose); } static struct nfsd_fcache_disposal * -nfsd_alloc_fcache_disposal(struct net *net) +nfsd_alloc_fcache_disposal(void) { struct nfsd_fcache_disposal *l; @@ -763,7 +914,6 @@ nfsd_alloc_fcache_disposal(struct net *net) if (!l) return NULL; INIT_WORK(&l->work, nfsd_file_delayed_close); - l->net = net; spin_lock_init(&l->lock); INIT_LIST_HEAD(&l->freeme); return l; @@ -772,61 +922,40 @@ nfsd_alloc_fcache_disposal(struct net *net) static void nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l) { - rcu_assign_pointer(l->net, NULL); cancel_work_sync(&l->work); nfsd_file_dispose_list(&l->freeme); - kfree_rcu(l, rcu); -} - -static void -nfsd_add_fcache_disposal(struct nfsd_fcache_disposal *l) -{ - spin_lock(&laundrette_lock); - list_add_tail_rcu(&l->list, &laundrettes); - spin_unlock(&laundrette_lock); + kfree(l); } static void -nfsd_del_fcache_disposal(struct nfsd_fcache_disposal *l) -{ - spin_lock(&laundrette_lock); - list_del_rcu(&l->list); - spin_unlock(&laundrette_lock); -} - -static int -nfsd_alloc_fcache_disposal_net(struct net *net) +nfsd_free_fcache_disposal_net(struct net *net) { - struct nfsd_fcache_disposal *l; + struct nfsd_net *nn = net_generic(net, nfsd_net_id); + struct nfsd_fcache_disposal *l = nn->fcache_disposal; - l = nfsd_alloc_fcache_disposal(net); - if (!l) - return -ENOMEM; - nfsd_add_fcache_disposal(l); - return 0; + nfsd_free_fcache_disposal(l); } -static void -nfsd_free_fcache_disposal_net(struct net *net) +int +nfsd_file_cache_start_net(struct net *net) { - struct nfsd_fcache_disposal *l; + struct nfsd_net *nn = net_generic(net, nfsd_net_id); - rcu_read_lock(); - list_for_each_entry_rcu(l, &laundrettes, list) { - if (l->net != net) - continue; - nfsd_del_fcache_disposal(l); - rcu_read_unlock(); - nfsd_free_fcache_disposal(l); - return; - } - rcu_read_unlock(); + nn->fcache_disposal = nfsd_alloc_fcache_disposal(); + return nn->fcache_disposal ? 0 : -ENOMEM; } -int -nfsd_file_cache_start_net(struct net *net) +/** + * nfsd_file_cache_purge - Remove all cache items associated with @net + * @net: target net namespace + * + */ +void +nfsd_file_cache_purge(struct net *net) { - return nfsd_alloc_fcache_disposal_net(net); + lockdep_assert_held(&nfsd_mutex); + if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1) + __nfsd_file_cache_purge(net); } void @@ -839,7 +968,11 @@ nfsd_file_cache_shutdown_net(struct net *net) void nfsd_file_cache_shutdown(void) { - set_bit(NFSD_FILE_SHUTDOWN, &nfsd_file_lru_flags); + int i; + + lockdep_assert_held(&nfsd_mutex); + if (test_and_clear_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 0) + return; lease_unregister_notifier(&nfsd_file_lease_notifier); unregister_shrinker(&nfsd_file_shrinker); @@ -848,7 +981,7 @@ nfsd_file_cache_shutdown(void) * calling nfsd_file_cache_purge */ cancel_delayed_work_sync(&nfsd_filecache_laundrette); - nfsd_file_cache_purge(NULL); + __nfsd_file_cache_purge(NULL); list_lru_destroy(&nfsd_file_lru); rcu_barrier(); fsnotify_put_group(nfsd_file_fsnotify_group); @@ -858,240 +991,241 @@ nfsd_file_cache_shutdown(void) fsnotify_wait_marks_destroyed(); kmem_cache_destroy(nfsd_file_mark_slab); nfsd_file_mark_slab = NULL; - kfree(nfsd_file_hashtbl); - nfsd_file_hashtbl = NULL; destroy_workqueue(nfsd_filecache_wq); nfsd_filecache_wq = NULL; -} - -static bool -nfsd_match_cred(const struct cred *c1, const struct cred *c2) -{ - int i; - - if (!uid_eq(c1->fsuid, c2->fsuid)) - return false; - if (!gid_eq(c1->fsgid, c2->fsgid)) - return false; - if (c1->group_info == NULL || c2->group_info == NULL) - return c1->group_info == c2->group_info; - if (c1->group_info->ngroups != c2->group_info->ngroups) - return false; - for (i = 0; i < c1->group_info->ngroups; i++) { - if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i])) - return false; - } - return true; -} - -static struct nfsd_file * -nfsd_file_find_locked(struct inode *inode, unsigned int may_flags, - unsigned int hashval, struct net *net) -{ - struct nfsd_file *nf; - unsigned char need = may_flags & NFSD_FILE_MAY_MASK; - - hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head, - nf_node, lockdep_is_held(&nfsd_file_hashtbl[hashval].nfb_lock)) { - if (nf->nf_may != need) - continue; - if (nf->nf_inode != inode) - continue; - if (nf->nf_net != net) - continue; - if (!nfsd_match_cred(nf->nf_cred, current_cred())) - continue; - if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) - continue; - if (nfsd_file_get(nf) != NULL) - return nf; + rhashtable_destroy(&nfsd_file_rhash_tbl); + + for_each_possible_cpu(i) { + per_cpu(nfsd_file_cache_hits, i) = 0; + per_cpu(nfsd_file_acquisitions, i) = 0; + per_cpu(nfsd_file_releases, i) = 0; + per_cpu(nfsd_file_total_age, i) = 0; + per_cpu(nfsd_file_pages_flushed, i) = 0; + per_cpu(nfsd_file_evictions, i) = 0; } - return NULL; } /** - * nfsd_file_is_cached - are there any cached open files for this fh? - * @inode: inode of the file to check + * nfsd_file_is_cached - are there any cached open files for this inode? + * @inode: inode to check * - * Scan the hashtable for open files that match this fh. Returns true if there - * are any, and false if not. + * The lookup matches inodes in all net namespaces and is atomic wrt + * nfsd_file_acquire(). + * + * Return values: + * %true: filecache contains at least one file matching this inode + * %false: filecache contains no files matching this inode */ bool nfsd_file_is_cached(struct inode *inode) { - bool ret = false; - struct nfsd_file *nf; - unsigned int hashval; - - hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS); - - rcu_read_lock(); - hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head, - nf_node) { - if (inode == nf->nf_inode) { - ret = true; - break; - } - } - rcu_read_unlock(); - trace_nfsd_file_is_cached(inode, hashval, (int)ret); + struct nfsd_file_lookup_key key = { + .type = NFSD_FILE_KEY_INODE, + .inode = inode, + }; + bool ret = false; + + if (rhashtable_lookup_fast(&nfsd_file_rhash_tbl, &key, + nfsd_file_rhash_params) != NULL) + ret = true; + trace_nfsd_file_is_cached(inode, (int)ret); return ret; } -__be32 -nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, - unsigned int may_flags, struct nfsd_file **pnf) +static __be32 +nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, + unsigned int may_flags, struct nfsd_file **pnf, bool open) { - __be32 status; - struct net *net = SVC_NET(rqstp); - struct nfsd_file *nf, *new; - struct inode *inode; - unsigned int hashval; - bool retry = true; - - /* FIXME: skip this if fh_dentry is already set? */ + struct nfsd_file_lookup_key key = { + .type = NFSD_FILE_KEY_FULL, + .need = may_flags & NFSD_FILE_MAY_MASK, + .net = SVC_NET(rqstp), + }; + bool open_retry = true; + struct nfsd_file *nf; + __be32 status; + int ret; + status = fh_verify(rqstp, fhp, S_IFREG, may_flags|NFSD_MAY_OWNER_OVERRIDE); if (status != nfs_ok) return status; + key.inode = d_inode(fhp->fh_dentry); + key.cred = get_current_cred(); - inode = d_inode(fhp->fh_dentry); - hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS); retry: rcu_read_lock(); - nf = nfsd_file_find_locked(inode, may_flags, hashval, net); + nf = rhashtable_lookup(&nfsd_file_rhash_tbl, &key, + nfsd_file_rhash_params); + if (nf) + nf = nfsd_file_get(nf); rcu_read_unlock(); if (nf) goto wait_for_construction; - new = nfsd_file_alloc(inode, may_flags, hashval, net); - if (!new) { - trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags, - NULL, nfserr_jukebox); - return nfserr_jukebox; + nf = nfsd_file_alloc(&key, may_flags); + if (!nf) { + status = nfserr_jukebox; + goto out_status; } - spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock); - nf = nfsd_file_find_locked(inode, may_flags, hashval, net); - if (nf == NULL) + ret = rhashtable_lookup_insert_key(&nfsd_file_rhash_tbl, + &key, &nf->nf_rhash, + nfsd_file_rhash_params); + if (likely(ret == 0)) goto open_file; - spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock); - nfsd_file_slab_free(&new->nf_rcu); + + nfsd_file_slab_free(&nf->nf_rcu); + nf = NULL; + if (ret == -EEXIST) + goto retry; + trace_nfsd_file_insert_err(rqstp, key.inode, may_flags, ret); + status = nfserr_jukebox; + goto out_status; wait_for_construction: wait_on_bit(&nf->nf_flags, NFSD_FILE_PENDING, TASK_UNINTERRUPTIBLE); /* Did construction of this file fail? */ if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { - if (!retry) { + trace_nfsd_file_cons_err(rqstp, key.inode, may_flags, nf); + if (!open_retry) { status = nfserr_jukebox; goto out; } - retry = false; + open_retry = false; nfsd_file_put_noref(nf); goto retry; } + nfsd_file_lru_remove(nf); this_cpu_inc(nfsd_file_cache_hits); - if (!(may_flags & NFSD_MAY_NOT_BREAK_LEASE)) { - bool write = (may_flags & NFSD_MAY_WRITE); - - if (test_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags) || - (test_bit(NFSD_FILE_BREAK_WRITE, &nf->nf_flags) && write)) { - status = nfserrno(nfsd_open_break_lease( - file_inode(nf->nf_file), may_flags)); - if (status == nfs_ok) { - clear_bit(NFSD_FILE_BREAK_READ, &nf->nf_flags); - if (write) - clear_bit(NFSD_FILE_BREAK_WRITE, - &nf->nf_flags); - } - } - } + status = nfserrno(nfsd_open_break_lease(file_inode(nf->nf_file), may_flags)); out: if (status == nfs_ok) { + if (open) + this_cpu_inc(nfsd_file_acquisitions); *pnf = nf; } else { nfsd_file_put(nf); nf = NULL; } - trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags, nf, status); +out_status: + put_cred(key.cred); + if (open) + trace_nfsd_file_acquire(rqstp, key.inode, may_flags, nf, status); return status; + open_file: - nf = new; - /* Take reference for the hashtable */ - refcount_inc(&nf->nf_ref); - __set_bit(NFSD_FILE_HASHED, &nf->nf_flags); - __set_bit(NFSD_FILE_PENDING, &nf->nf_flags); - list_lru_add(&nfsd_file_lru, &nf->nf_lru); - hlist_add_head_rcu(&nf->nf_node, &nfsd_file_hashtbl[hashval].nfb_head); - ++nfsd_file_hashtbl[hashval].nfb_count; - nfsd_file_hashtbl[hashval].nfb_maxcount = max(nfsd_file_hashtbl[hashval].nfb_maxcount, - nfsd_file_hashtbl[hashval].nfb_count); - spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock); - if (atomic_long_inc_return(&nfsd_filecache_count) >= NFSD_FILE_LRU_THRESHOLD) - nfsd_file_gc(); - - nf->nf_mark = nfsd_file_mark_find_or_create(nf); - if (nf->nf_mark) - status = nfsd_open_verified(rqstp, fhp, S_IFREG, - may_flags, &nf->nf_file); - else + trace_nfsd_file_alloc(nf); + nf->nf_mark = nfsd_file_mark_find_or_create(nf, key.inode); + if (nf->nf_mark) { + if (open) { + status = nfsd_open_verified(rqstp, fhp, may_flags, + &nf->nf_file); + trace_nfsd_file_open(nf, status); + } else + status = nfs_ok; + } else status = nfserr_jukebox; /* * If construction failed, or we raced with a call to unlink() * then unhash. */ - if (status != nfs_ok || inode->i_nlink == 0) { - bool do_free; - spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock); - do_free = nfsd_file_unhash(nf); - spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock); - if (do_free) + if (status != nfs_ok || key.inode->i_nlink == 0) + if (nfsd_file_unhash(nf)) nfsd_file_put_noref(nf); - } clear_bit_unlock(NFSD_FILE_PENDING, &nf->nf_flags); smp_mb__after_atomic(); wake_up_bit(&nf->nf_flags, NFSD_FILE_PENDING); goto out; } +/** + * nfsd_file_acquire - Get a struct nfsd_file with an open file + * @rqstp: the RPC transaction being executed + * @fhp: the NFS filehandle of the file to be opened + * @may_flags: NFSD_MAY_ settings for the file + * @pnf: OUT: new or found "struct nfsd_file" object + * + * Returns nfs_ok and sets @pnf on success; otherwise an nfsstat in + * network byte order is returned. + */ +__be32 +nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, + unsigned int may_flags, struct nfsd_file **pnf) +{ + return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, true); +} + +/** + * nfsd_file_create - Get a struct nfsd_file, do not open + * @rqstp: the RPC transaction being executed + * @fhp: the NFS filehandle of the file just created + * @may_flags: NFSD_MAY_ settings for the file + * @pnf: OUT: new or found "struct nfsd_file" object + * + * Returns nfs_ok and sets @pnf on success; otherwise an nfsstat in + * network byte order is returned. + */ +__be32 +nfsd_file_create(struct svc_rqst *rqstp, struct svc_fh *fhp, + unsigned int may_flags, struct nfsd_file **pnf) +{ + return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, false); +} + /* * Note that fields may be added, removed or reordered in the future. Programs * scraping this file for info should test the labels to ensure they're * getting the correct field. */ -static int nfsd_file_cache_stats_show(struct seq_file *m, void *v) +int nfsd_file_cache_stats_show(struct seq_file *m, void *v) { - unsigned int i, count = 0, longest = 0; - unsigned long hits = 0; + unsigned long releases = 0, pages_flushed = 0, evictions = 0; + unsigned long hits = 0, acquisitions = 0; + unsigned int i, count = 0, buckets = 0; + unsigned long lru = 0, total_age = 0; - /* - * No need for spinlocks here since we're not terribly interested in - * accuracy. We do take the nfsd_mutex simply to ensure that we - * don't end up racing with server shutdown - */ + /* Serialize with server shutdown */ mutex_lock(&nfsd_mutex); - if (nfsd_file_hashtbl) { - for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) { - count += nfsd_file_hashtbl[i].nfb_count; - longest = max(longest, nfsd_file_hashtbl[i].nfb_count); - } + if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1) { + struct bucket_table *tbl; + struct rhashtable *ht; + + lru = list_lru_count(&nfsd_file_lru); + + rcu_read_lock(); + ht = &nfsd_file_rhash_tbl; + count = atomic_read(&ht->nelems); + tbl = rht_dereference_rcu(ht->tbl, ht); + buckets = tbl->size; + rcu_read_unlock(); } mutex_unlock(&nfsd_mutex); - for_each_possible_cpu(i) + for_each_possible_cpu(i) { hits += per_cpu(nfsd_file_cache_hits, i); + acquisitions += per_cpu(nfsd_file_acquisitions, i); + releases += per_cpu(nfsd_file_releases, i); + total_age += per_cpu(nfsd_file_total_age, i); + evictions += per_cpu(nfsd_file_evictions, i); + pages_flushed += per_cpu(nfsd_file_pages_flushed, i); + } seq_printf(m, "total entries: %u\n", count); - seq_printf(m, "longest chain: %u\n", longest); + seq_printf(m, "hash buckets: %u\n", buckets); + seq_printf(m, "lru entries: %lu\n", lru); seq_printf(m, "cache hits: %lu\n", hits); + seq_printf(m, "acquisitions: %lu\n", acquisitions); + seq_printf(m, "releases: %lu\n", releases); + seq_printf(m, "evictions: %lu\n", evictions); + if (releases) + seq_printf(m, "mean age (ms): %ld\n", total_age / releases); + else + seq_printf(m, "mean age (ms): -\n"); + seq_printf(m, "pages flushed: %lu\n", pages_flushed); return 0; } - -int nfsd_file_cache_stats_open(struct inode *inode, struct file *file) -{ - return single_open(file, nfsd_file_cache_stats_show, NULL); -} |