// SPDX-License-Identifier: GPL-2.0 /* * The NFSD open file cache. * * (c) 2015 - Jeff Layton * * An nfsd_file object is a per-file collection of open state that binds * together: * - a struct file * * - a user credential * - a network namespace * - a read-ahead context * - monitoring for writeback errors * * nfsd_file objects are reference-counted. Consumers acquire a new * object via the nfsd_file_acquire API. They manage their interest in * the acquired object, and hence the object's reference count, via * nfsd_file_get and nfsd_file_put. There are two varieties of nfsd_file * object: * * * non-garbage-collected: When a consumer wants to precisely control * the lifetime of a file's open state, it acquires a non-garbage- * collected nfsd_file. The final nfsd_file_put releases the open * state immediately. * * * garbage-collected: When a consumer does not control the lifetime * of open state, it acquires a garbage-collected nfsd_file. The * final nfsd_file_put allows the open state to linger for a period * during which it may be re-used. */ #include #include #include #include #include #include #include #include #include #include #include "vfs.h" #include "nfsd.h" #include "nfsfh.h" #include "netns.h" #include "filecache.h" #include "trace.h" #define NFSD_LAUNDRETTE_DELAY (2 * HZ) #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|NFSD_MAY_LOCALIO) 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_allocations); 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_evictions); struct nfsd_fcache_disposal { spinlock_t lock; struct list_head freeme; }; static struct kmem_cache *nfsd_file_slab; static struct kmem_cache *nfsd_file_mark_slab; static struct list_lru nfsd_file_lru; static unsigned long nfsd_file_flags; static struct fsnotify_group *nfsd_file_fsnotify_group; static struct delayed_work nfsd_filecache_laundrette; static struct rhltable nfsd_file_rhltable ____cacheline_aligned_in_smp; 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 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_rlist), /* * Start with a single page hash table to reduce resizing churn * on light workloads. */ .min_size = 256, .automatic_shrinking = true, }; static void nfsd_file_schedule_laundrette(void) { if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags)) queue_delayed_work(system_unbound_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 inode *inode) { int err; struct fsnotify_mark *mark; struct nfsd_file_mark *nfm = NULL, *new; do { fsnotify_group_lock(nfsd_file_fsnotify_group); mark = fsnotify_find_inode_mark(inode, nfsd_file_fsnotify_group); if (mark) { nfm = nfsd_file_mark_get(container_of(mark, struct nfsd_file_mark, nfm_mark)); fsnotify_group_unlock(nfsd_file_fsnotify_group); 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 { fsnotify_group_unlock(nfsd_file_fsnotify_group); } /* allocate a new nfm */ new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL); if (!new) return NULL; fsnotify_init_mark(&new->nfm_mark, nfsd_file_fsnotify_group); new->nfm_mark.mask = FS_ATTRIB|FS_DELETE_SELF; refcount_set(&new->nfm_ref, 1); err = fsnotify_add_inode_mark(&new->nfm_mark, inode, 0); /* * If the add was successful, then return the object. * Otherwise, we need to put the reference we hold on the * nfm_mark. The fsnotify code will take a reference and put * it on failure, so we can't just free it directly. It's also * not safe to call fsnotify_destroy_mark on it as the * mark->group will be NULL. Thus, we can't let the nfm_ref * counter drive the destruction at this point. */ if (likely(!err)) nfm = new; else fsnotify_put_mark(&new->nfm_mark); } while (unlikely(err == -EEXIST)); return nfm; } static struct nfsd_file * nfsd_file_alloc(struct net *net, struct inode *inode, unsigned char need, bool want_gc) { struct nfsd_file *nf; nf = kmem_cache_alloc(nfsd_file_slab, GFP_KERNEL); if (unlikely(!nf)) return NULL; this_cpu_inc(nfsd_file_allocations); INIT_LIST_HEAD(&nf->nf_lru); INIT_LIST_HEAD(&nf->nf_gc); nf->nf_birthtime = ktime_get(); nf->nf_file = NULL; nf->nf_cred = get_current_cred(); nf->nf_net = net; nf->nf_flags = want_gc ? BIT(NFSD_FILE_HASHED) | BIT(NFSD_FILE_PENDING) | BIT(NFSD_FILE_GC) : BIT(NFSD_FILE_HASHED) | BIT(NFSD_FILE_PENDING); nf->nf_inode = inode; refcount_set(&nf->nf_ref, 1); nf->nf_may = need; nf->nf_mark = NULL; return nf; } /** * nfsd_file_check_write_error - check for writeback errors on a file * @nf: nfsd_file to check for writeback errors * * Check whether a nfsd_file has an unseen error. Reset the write * verifier if so. */ static void nfsd_file_check_write_error(struct nfsd_file *nf) { struct file *file = nf->nf_file; if ((file->f_mode & FMODE_WRITE) && filemap_check_wb_err(file->f_mapping, READ_ONCE(file->f_wb_err))) nfsd_reset_write_verifier(net_generic(nf->nf_net, nfsd_net_id)); } static void nfsd_file_hash_remove(struct nfsd_file *nf) { trace_nfsd_file_unhash(nf); rhltable_remove(&nfsd_file_rhltable, &nf->nf_rlist, 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_hash_remove(nf); return true; } return false; } static void nfsd_file_free(struct nfsd_file *nf) { s64 age = ktime_to_ms(ktime_sub(ktime_get(), nf->nf_birthtime)); trace_nfsd_file_free(nf); this_cpu_inc(nfsd_file_releases); this_cpu_add(nfsd_file_total_age, age); nfsd_file_unhash(nf); if (nf->nf_mark) nfsd_file_mark_put(nf->nf_mark); if (nf->nf_file) { nfsd_file_check_write_error(nf); nfsd_filp_close(nf->nf_file); } /* * 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; call_rcu(&nf->nf_rcu, nfsd_file_slab_free); } static bool nfsd_file_check_writeback(struct nfsd_file *nf) { struct file *file = nf->nf_file; struct address_space *mapping; /* File not open for write? */ if (!(file->f_mode & FMODE_WRITE)) return false; /* * Some filesystems (e.g. NFS) flush all dirty data on close. * On others, there is no need to wait for writeback. */ if (!(file_inode(file)->i_sb->s_export_op->flags & EXPORT_OP_FLUSH_ON_CLOSE)) return false; mapping = file->f_mapping; return mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) || mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK); } static bool nfsd_file_lru_add(struct nfsd_file *nf) { set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags); if (list_lru_add_obj(&nfsd_file_lru, &nf->nf_lru)) { trace_nfsd_file_lru_add(nf); return true; } return false; } static bool nfsd_file_lru_remove(struct nfsd_file *nf) { if (list_lru_del_obj(&nfsd_file_lru, &nf->nf_lru)) { trace_nfsd_file_lru_del(nf); return true; } return false; } struct nfsd_file * nfsd_file_get(struct nfsd_file *nf) { if (nf && refcount_inc_not_zero(&nf->nf_ref)) return nf; return NULL; } /** * nfsd_file_put - put the reference to a nfsd_file * @nf: nfsd_file of which to put the reference * * Put a reference to a nfsd_file. In the non-GC case, we just put the * reference immediately. In the GC case, if the reference would be * the last one, the put it on the LRU instead to be cleaned up later. */ void nfsd_file_put(struct nfsd_file *nf) { might_sleep(); trace_nfsd_file_put(nf); if (test_bit(NFSD_FILE_GC, &nf->nf_flags) && test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { /* * If this is the last reference (nf_ref == 1), then try to * transfer it to the LRU. */ if (refcount_dec_not_one(&nf->nf_ref)) return; /* Try to add it to the LRU. If that fails, decrement. */ if (nfsd_file_lru_add(nf)) { /* If it's still hashed, we're done */ if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { nfsd_file_schedule_laundrette(); return; } /* * We're racing with unhashing, so try to remove it from * the LRU. If removal fails, then someone else already * has our reference. */ if (!nfsd_file_lru_remove(nf)) return; } } if (refcount_dec_and_test(&nf->nf_ref)) nfsd_file_free(nf); } /** * nfsd_file_put_local - put nfsd_file reference and arm nfsd_serv_put in caller * @nf: nfsd_file of which to put the reference * * First save the associated net to return to caller, then put * the reference of the nfsd_file. */ struct net * nfsd_file_put_local(struct nfsd_file *nf) { struct net *net = nf->nf_net; nfsd_file_put(nf); return net; } /** * nfsd_file_file - get the backing file of an nfsd_file * @nf: nfsd_file of which to access the backing file. * * Return backing file for @nf. */ struct file * nfsd_file_file(struct nfsd_file *nf) { return nf->nf_file; } static void nfsd_file_dispose_list(struct list_head *dispose) { struct nfsd_file *nf; while (!list_empty(dispose)) { nf = list_first_entry(dispose, struct nfsd_file, nf_gc); list_del_init(&nf->nf_gc); nfsd_file_free(nf); } } /** * nfsd_file_dispose_list_delayed - move list of dead files to net's freeme list * @dispose: list of nfsd_files to be disposed * * Transfers each file to the "freeme" list for its nfsd_net, to eventually * be disposed of by the per-net garbage collector. */ static void nfsd_file_dispose_list_delayed(struct list_head *dispose) { while(!list_empty(dispose)) { struct nfsd_file *nf = list_first_entry(dispose, struct nfsd_file, nf_gc); struct nfsd_net *nn = net_generic(nf->nf_net, nfsd_net_id); struct nfsd_fcache_disposal *l = nn->fcache_disposal; spin_lock(&l->lock); list_move_tail(&nf->nf_gc, &l->freeme); spin_unlock(&l->lock); svc_wake_up(nn->nfsd_serv); } } /** * nfsd_file_net_dispose - deal with nfsd_files waiting to be disposed. * @nn: nfsd_net in which to find files to be disposed. * * When files held open for nfsv3 are removed from the filecache, whether * due to memory pressure or garbage collection, they are queued to * a per-net-ns queue. This function completes the disposal, either * directly or by waking another nfsd thread to help with the work. */ void nfsd_file_net_dispose(struct nfsd_net *nn) { struct nfsd_fcache_disposal *l = nn->fcache_disposal; if (!list_empty(&l->freeme)) { LIST_HEAD(dispose); int i; spin_lock(&l->lock); for (i = 0; i < 8 && !list_empty(&l->freeme); i++) list_move(l->freeme.next, &dispose); spin_unlock(&l->lock); if (!list_empty(&l->freeme)) /* Wake up another thread to share the work * *before* doing any actual disposing. */ svc_wake_up(nn->nfsd_serv); nfsd_file_dispose_list(&dispose); } } /** * nfsd_file_lru_cb - Examine an entry on the LRU list * @item: LRU entry to examine * @lru: controlling LRU * @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, void *arg) { struct list_head *head = arg; struct nfsd_file *nf = list_entry(item, struct nfsd_file, nf_lru); /* We should only be dealing with GC entries here */ WARN_ON_ONCE(!test_bit(NFSD_FILE_GC, &nf->nf_flags)); /* * Don't throw out files that are still undergoing I/O or * that have uncleared errors pending. */ if (nfsd_file_check_writeback(nf)) { trace_nfsd_file_gc_writeback(nf); return LRU_SKIP; } /* If it was recently added to the list, skip it */ if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags)) { trace_nfsd_file_gc_referenced(nf); return LRU_ROTATE; } /* * Put the reference held on behalf of the LRU. If it wasn't the last * one, then just remove it from the LRU and ignore it. */ if (!refcount_dec_and_test(&nf->nf_ref)) { trace_nfsd_file_gc_in_use(nf); list_lru_isolate(lru, &nf->nf_lru); return LRU_REMOVED; } /* Refcount went to zero. Unhash it and queue it to the dispose list */ nfsd_file_unhash(nf); list_lru_isolate(lru, &nf->nf_lru); list_add(&nf->nf_gc, head); this_cpu_inc(nfsd_file_evictions); trace_nfsd_file_gc_disposed(nf); return LRU_REMOVED; } static void nfsd_file_gc(void) { 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_dispose_list_delayed(&dispose); } static void nfsd_file_gc_worker(struct work_struct *work) { nfsd_file_gc(); if (list_lru_count(&nfsd_file_lru)) nfsd_file_schedule_laundrette(); } static unsigned long nfsd_file_lru_count(struct shrinker *s, struct shrink_control *sc) { return list_lru_count(&nfsd_file_lru); } static unsigned long nfsd_file_lru_scan(struct shrinker *s, struct shrink_control *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_dispose_list_delayed(&dispose); return ret; } static struct shrinker *nfsd_file_shrinker; /** * nfsd_file_cond_queue - conditionally unhash and queue a nfsd_file * @nf: nfsd_file to attempt to queue * @dispose: private list to queue successfully-put objects * * Unhash an nfsd_file, try to get a reference to it, and then put that * reference. If it's the last reference, queue it to the dispose list. */ static void nfsd_file_cond_queue(struct nfsd_file *nf, struct list_head *dispose) __must_hold(RCU) { int decrement = 1; /* If we raced with someone else unhashing, ignore it */ if (!nfsd_file_unhash(nf)) return; /* If we can't get a reference, ignore it */ if (!nfsd_file_get(nf)) return; /* Extra decrement if we remove from the LRU */ if (nfsd_file_lru_remove(nf)) ++decrement; /* If refcount goes to 0, then put on the dispose list */ if (refcount_sub_and_test(decrement, &nf->nf_ref)) { list_add(&nf->nf_gc, dispose); trace_nfsd_file_closing(nf); } } /** * nfsd_file_queue_for_close: try to close out any open nfsd_files for an inode * @inode: inode on which to close out nfsd_files * @dispose: list on which to gather nfsd_files to close out * * An nfsd_file represents a struct file being held open on behalf of nfsd. * An open file however can block other activity (such as leases), or cause * undesirable behavior (e.g. spurious silly-renames when reexporting NFS). * * This function is intended to find open nfsd_files when this sort of * conflicting access occurs and then attempt to close those files out. * * Populates the dispose list with entries that have already had their * refcounts go to zero. The actual free of an nfsd_file can be expensive, * so we leave it up to the caller whether it wants to wait or not. */ static void nfsd_file_queue_for_close(struct inode *inode, struct list_head *dispose) { struct rhlist_head *tmp, *list; struct nfsd_file *nf; rcu_read_lock(); list = rhltable_lookup(&nfsd_file_rhltable, &inode, nfsd_file_rhash_params); rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) { if (!test_bit(NFSD_FILE_GC, &nf->nf_flags)) continue; nfsd_file_cond_queue(nf, dispose); } rcu_read_unlock(); } /** * nfsd_file_close_inode - attempt a delayed close of a nfsd_file * @inode: inode of the file to attempt to remove * * Close out any open nfsd_files that can be reaped for @inode. The * actual freeing is deferred to the dispose_list_delayed infrastructure. * * This is used by the fsnotify callbacks and setlease notifier. */ static void nfsd_file_close_inode(struct inode *inode) { LIST_HEAD(dispose); nfsd_file_queue_for_close(inode, &dispose); nfsd_file_dispose_list_delayed(&dispose); } /** * nfsd_file_close_inode_sync - attempt to forcibly close a nfsd_file * @inode: inode of the file to attempt to remove * * Close out any open nfsd_files that can be reaped for @inode. The * nfsd_files are closed out synchronously. * * This is called from nfsd_rename and nfsd_unlink to avoid silly-renames * when reexporting NFS. */ void nfsd_file_close_inode_sync(struct inode *inode) { struct nfsd_file *nf; LIST_HEAD(dispose); trace_nfsd_file_close(inode); nfsd_file_queue_for_close(inode, &dispose); while (!list_empty(&dispose)) { nf = list_first_entry(&dispose, struct nfsd_file, nf_gc); list_del_init(&nf->nf_gc); nfsd_file_free(nf); } } static int nfsd_file_lease_notifier_call(struct notifier_block *nb, unsigned long arg, void *data) { struct file_lease *fl = data; /* Only close files for F_SETLEASE leases */ if (fl->c.flc_flags & FL_LEASE) nfsd_file_close_inode(file_inode(fl->c.flc_file)); return 0; } static struct notifier_block nfsd_file_lease_notifier = { .notifier_call = nfsd_file_lease_notifier_call, }; static int nfsd_file_fsnotify_handle_event(struct fsnotify_mark *mark, u32 mask, struct inode *inode, struct inode *dir, const struct qstr *name, u32 cookie) { if (WARN_ON_ONCE(!inode)) return 0; trace_nfsd_file_fsnotify_handle_event(inode, mask); /* Should be no marks on non-regular files */ if (!S_ISREG(inode->i_mode)) { WARN_ON_ONCE(1); return 0; } /* don't close files if this was not the last link */ if (mask & FS_ATTRIB) { if (inode->i_nlink) return 0; } nfsd_file_close_inode(inode); return 0; } static const struct fsnotify_ops nfsd_file_fsnotify_ops = { .handle_inode_event = nfsd_file_fsnotify_handle_event, .free_mark = nfsd_file_mark_free, }; int nfsd_file_cache_init(void) { int ret; lockdep_assert_held(&nfsd_mutex); if (test_and_set_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1) return 0; ret = rhltable_init(&nfsd_file_rhltable, &nfsd_file_rhash_params); if (ret) goto out; ret = -ENOMEM; nfsd_file_slab = KMEM_CACHE(nfsd_file, 0); if (!nfsd_file_slab) { pr_err("nfsd: unable to create nfsd_file_slab\n"); goto out_err; } nfsd_file_mark_slab = KMEM_CACHE(nfsd_file_mark, 0); if (!nfsd_file_mark_slab) { pr_err("nfsd: unable to create nfsd_file_mark_slab\n"); goto out_err; } ret = list_lru_init(&nfsd_file_lru); if (ret) { pr_err("nfsd: failed to init nfsd_file_lru: %d\n", ret); goto out_err; } nfsd_file_shrinker = shrinker_alloc(0, "nfsd-filecache"); if (!nfsd_file_shrinker) { ret = -ENOMEM; pr_err("nfsd: failed to allocate nfsd_file_shrinker\n"); goto out_lru; } nfsd_file_shrinker->count_objects = nfsd_file_lru_count; nfsd_file_shrinker->scan_objects = nfsd_file_lru_scan; nfsd_file_shrinker->seeks = 1; shrinker_register(nfsd_file_shrinker); ret = lease_register_notifier(&nfsd_file_lease_notifier); if (ret) { pr_err("nfsd: unable to register lease notifier: %d\n", ret); goto out_shrinker; } nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops, 0); if (IS_ERR(nfsd_file_fsnotify_group)) { pr_err("nfsd: unable to create fsnotify group: %ld\n", PTR_ERR(nfsd_file_fsnotify_group)); ret = PTR_ERR(nfsd_file_fsnotify_group); nfsd_file_fsnotify_group = NULL; goto out_notifier; } INIT_DELAYED_WORK(&nfsd_filecache_laundrette, nfsd_file_gc_worker); out: if (ret) clear_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags); return ret; out_notifier: lease_unregister_notifier(&nfsd_file_lease_notifier); out_shrinker: shrinker_free(nfsd_file_shrinker); out_lru: list_lru_destroy(&nfsd_file_lru); out_err: kmem_cache_destroy(nfsd_file_slab); nfsd_file_slab = NULL; kmem_cache_destroy(nfsd_file_mark_slab); nfsd_file_mark_slab = NULL; rhltable_destroy(&nfsd_file_rhltable); goto out; } /** * __nfsd_file_cache_purge: clean out the cache for shutdown * @net: net-namespace to shut down the cache (may be NULL) * * Walk the nfsd_file cache and close out any that match @net. If @net is NULL, * then close out everything. Called when an nfsd instance is being shut down, * and when the exports table is flushed. */ static void __nfsd_file_cache_purge(struct net *net) { struct rhashtable_iter iter; struct nfsd_file *nf; LIST_HEAD(dispose); rhltable_walk_enter(&nfsd_file_rhltable, &iter); do { rhashtable_walk_start(&iter); nf = rhashtable_walk_next(&iter); while (!IS_ERR_OR_NULL(nf)) { if (!net || nf->nf_net == net) nfsd_file_cond_queue(nf, &dispose); nf = rhashtable_walk_next(&iter); } rhashtable_walk_stop(&iter); } while (nf == ERR_PTR(-EAGAIN)); rhashtable_walk_exit(&iter); nfsd_file_dispose_list(&dispose); } static struct nfsd_fcache_disposal * nfsd_alloc_fcache_disposal(void) { struct nfsd_fcache_disposal *l; l = kmalloc(sizeof(*l), GFP_KERNEL); if (!l) return NULL; spin_lock_init(&l->lock); INIT_LIST_HEAD(&l->freeme); return l; } static void nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l) { nfsd_file_dispose_list(&l->freeme); kfree(l); } static void nfsd_free_fcache_disposal_net(struct net *net) { struct nfsd_net *nn = net_generic(net, nfsd_net_id); struct nfsd_fcache_disposal *l = nn->fcache_disposal; nfsd_free_fcache_disposal(l); } int nfsd_file_cache_start_net(struct net *net) { struct nfsd_net *nn = net_generic(net, nfsd_net_id); nn->fcache_disposal = nfsd_alloc_fcache_disposal(); return nn->fcache_disposal ? 0 : -ENOMEM; } /** * nfsd_file_cache_purge - Remove all cache items associated with @net * @net: target net namespace * */ void nfsd_file_cache_purge(struct net *net) { lockdep_assert_held(&nfsd_mutex); if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1) __nfsd_file_cache_purge(net); } void nfsd_file_cache_shutdown_net(struct net *net) { nfsd_file_cache_purge(net); nfsd_free_fcache_disposal_net(net); } void nfsd_file_cache_shutdown(void) { 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); shrinker_free(nfsd_file_shrinker); /* * make sure all callers of nfsd_file_lru_cb are done before * calling nfsd_file_cache_purge */ cancel_delayed_work_sync(&nfsd_filecache_laundrette); __nfsd_file_cache_purge(NULL); list_lru_destroy(&nfsd_file_lru); rcu_barrier(); fsnotify_put_group(nfsd_file_fsnotify_group); nfsd_file_fsnotify_group = NULL; kmem_cache_destroy(nfsd_file_slab); nfsd_file_slab = NULL; fsnotify_wait_marks_destroyed(); kmem_cache_destroy(nfsd_file_mark_slab); nfsd_file_mark_slab = NULL; rhltable_destroy(&nfsd_file_rhltable); for_each_possible_cpu(i) { per_cpu(nfsd_file_cache_hits, i) = 0; per_cpu(nfsd_file_acquisitions, i) = 0; per_cpu(nfsd_file_allocations, i) = 0; per_cpu(nfsd_file_releases, i) = 0; per_cpu(nfsd_file_total_age, i) = 0; per_cpu(nfsd_file_evictions, i) = 0; } } static struct nfsd_file * nfsd_file_lookup_locked(const struct net *net, const struct cred *cred, struct inode *inode, unsigned char need, bool want_gc) { struct rhlist_head *tmp, *list; struct nfsd_file *nf; list = rhltable_lookup(&nfsd_file_rhltable, &inode, nfsd_file_rhash_params); rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) { if (nf->nf_may != need) continue; if (nf->nf_net != net) continue; if (!nfsd_match_cred(nf->nf_cred, cred)) continue; if (test_bit(NFSD_FILE_GC, &nf->nf_flags) != want_gc) continue; if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0) continue; if (!nfsd_file_get(nf)) continue; return nf; } return NULL; } /** * nfsd_file_is_cached - are there any cached open files for this inode? * @inode: inode to check * * 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) { struct rhlist_head *tmp, *list; struct nfsd_file *nf; bool ret = false; rcu_read_lock(); list = rhltable_lookup(&nfsd_file_rhltable, &inode, nfsd_file_rhash_params); rhl_for_each_entry_rcu(nf, tmp, list, nf_rlist) if (test_bit(NFSD_FILE_GC, &nf->nf_flags)) { ret = true; break; } rcu_read_unlock(); trace_nfsd_file_is_cached(inode, (int)ret); return ret; } static __be32 nfsd_file_do_acquire(struct svc_rqst *rqstp, struct net *net, struct svc_cred *cred, struct auth_domain *client, struct svc_fh *fhp, unsigned int may_flags, struct file *file, struct nfsd_file **pnf, bool want_gc) { unsigned char need = may_flags & NFSD_FILE_MAY_MASK; struct nfsd_file *new, *nf; bool stale_retry = true; bool open_retry = true; struct inode *inode; __be32 status; int ret; retry: if (rqstp) { status = fh_verify(rqstp, fhp, S_IFREG, may_flags|NFSD_MAY_OWNER_OVERRIDE); } else { status = fh_verify_local(net, cred, client, fhp, S_IFREG, may_flags|NFSD_MAY_OWNER_OVERRIDE); } if (status != nfs_ok) return status; inode = d_inode(fhp->fh_dentry); rcu_read_lock(); nf = nfsd_file_lookup_locked(net, current_cred(), inode, need, want_gc); rcu_read_unlock(); if (nf) { /* * If the nf is on the LRU then it holds an extra reference * that must be put if it's removed. It had better not be * the last one however, since we should hold another. */ if (nfsd_file_lru_remove(nf)) refcount_dec(&nf->nf_ref); goto wait_for_construction; } new = nfsd_file_alloc(net, inode, need, want_gc); if (!new) { status = nfserr_jukebox; goto out; } rcu_read_lock(); spin_lock(&inode->i_lock); nf = nfsd_file_lookup_locked(net, current_cred(), inode, need, want_gc); if (unlikely(nf)) { spin_unlock(&inode->i_lock); rcu_read_unlock(); nfsd_file_free(new); goto wait_for_construction; } nf = new; ret = rhltable_insert(&nfsd_file_rhltable, &nf->nf_rlist, nfsd_file_rhash_params); spin_unlock(&inode->i_lock); rcu_read_unlock(); if (likely(ret == 0)) goto open_file; trace_nfsd_file_insert_err(rqstp, inode, may_flags, ret); status = nfserr_jukebox; goto construction_err; 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)) { trace_nfsd_file_cons_err(rqstp, inode, may_flags, nf); if (!open_retry) { status = nfserr_jukebox; goto construction_err; } nfsd_file_put(nf); open_retry = false; fh_put(fhp); goto retry; } this_cpu_inc(nfsd_file_cache_hits); status = nfserrno(nfsd_open_break_lease(file_inode(nf->nf_file), may_flags)); if (status != nfs_ok) { nfsd_file_put(nf); nf = NULL; } out: if (status == nfs_ok) { this_cpu_inc(nfsd_file_acquisitions); nfsd_file_check_write_error(nf); *pnf = nf; } trace_nfsd_file_acquire(rqstp, inode, may_flags, nf, status); return status; open_file: trace_nfsd_file_alloc(nf); nf->nf_mark = nfsd_file_mark_find_or_create(inode); if (nf->nf_mark) { if (file) { get_file(file); nf->nf_file = file; status = nfs_ok; trace_nfsd_file_opened(nf, status); } else { ret = nfsd_open_verified(fhp, may_flags, &nf->nf_file); if (ret == -EOPENSTALE && stale_retry) { stale_retry = false; nfsd_file_unhash(nf); clear_and_wake_up_bit(NFSD_FILE_PENDING, &nf->nf_flags); if (refcount_dec_and_test(&nf->nf_ref)) nfsd_file_free(nf); nf = NULL; fh_put(fhp); goto retry; } status = nfserrno(ret); trace_nfsd_file_open(nf, status); } } 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) nfsd_file_unhash(nf); clear_and_wake_up_bit(NFSD_FILE_PENDING, &nf->nf_flags); if (status == nfs_ok) goto out; construction_err: if (refcount_dec_and_test(&nf->nf_ref)) nfsd_file_free(nf); nf = NULL; goto out; } /** * nfsd_file_acquire_gc - 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 * * The nfsd_file object returned by this API is reference-counted * and garbage-collected. The object is retained for a few * seconds after the final nfsd_file_put() in case the caller * wants to re-use it. * * Return values: * %nfs_ok - @pnf points to an nfsd_file with its reference * count boosted. * * On error, an nfsstat value in network byte order is returned. */ __be32 nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp, unsigned int may_flags, struct nfsd_file **pnf) { return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, NULL, fhp, may_flags, NULL, pnf, true); } /** * 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 * * The nfsd_file_object returned by this API is reference-counted * but not garbage-collected. The object is unhashed after the * final nfsd_file_put(). * * Return values: * %nfs_ok - @pnf points to an nfsd_file with its reference * count boosted. * * On error, an nfsstat value 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, SVC_NET(rqstp), NULL, NULL, fhp, may_flags, NULL, pnf, false); } /** * nfsd_file_acquire_local - Get a struct nfsd_file with an open file for localio * @net: The network namespace in which to perform a lookup * @cred: the user credential with which to validate access * @client: the auth_domain for LOCALIO lookup * @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 * * This file lookup interface provide access to a file given the * filehandle and credential. No connection-based authorisation * is performed and in that way it is quite different to other * file access mediated by nfsd. It allows a kernel module such as the NFS * client to reach across network and filesystem namespaces to access * a file. The security implications of this should be carefully * considered before use. * * The nfsd_file object returned by this API is reference-counted * and garbage-collected. The object is retained for a few * seconds after the final nfsd_file_put() in case the caller * wants to re-use it. * * Return values: * %nfs_ok - @pnf points to an nfsd_file with its reference * count boosted. * * On error, an nfsstat value in network byte order is returned. */ __be32 nfsd_file_acquire_local(struct net *net, struct svc_cred *cred, struct auth_domain *client, struct svc_fh *fhp, unsigned int may_flags, struct nfsd_file **pnf) { /* * Save creds before calling nfsd_file_do_acquire() (which calls * nfsd_setuser). Important because caller (LOCALIO) is from * client context. */ const struct cred *save_cred = get_current_cred(); __be32 beres; beres = nfsd_file_do_acquire(NULL, net, cred, client, fhp, may_flags, NULL, pnf, true); revert_creds(save_cred); return beres; } /** * nfsd_file_acquire_opened - Get a struct nfsd_file using existing open file * @rqstp: the RPC transaction being executed * @fhp: the NFS filehandle of the file just created * @may_flags: NFSD_MAY_ settings for the file * @file: cached, already-open file (may be NULL) * @pnf: OUT: new or found "struct nfsd_file" object * * Acquire a nfsd_file object that is not GC'ed. If one doesn't already exist, * and @file is non-NULL, use it to instantiate a new nfsd_file instead of * opening a new one. * * Return values: * %nfs_ok - @pnf points to an nfsd_file with its reference * count boosted. * * On error, an nfsstat value in network byte order is returned. */ __be32 nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp, unsigned int may_flags, struct file *file, struct nfsd_file **pnf) { return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, NULL, fhp, may_flags, file, 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. */ int nfsd_file_cache_stats_show(struct seq_file *m, void *v) { unsigned long allocations = 0, releases = 0, evictions = 0; unsigned long hits = 0, acquisitions = 0; unsigned int i, count = 0, buckets = 0; unsigned long lru = 0, total_age = 0; /* Serialize with server shutdown */ mutex_lock(&nfsd_mutex); 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_rhltable.ht; 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) { hits += per_cpu(nfsd_file_cache_hits, i); acquisitions += per_cpu(nfsd_file_acquisitions, i); allocations += per_cpu(nfsd_file_allocations, i); releases += per_cpu(nfsd_file_releases, i); total_age += per_cpu(nfsd_file_total_age, i); evictions += per_cpu(nfsd_file_evictions, i); } seq_printf(m, "total inodes: %u\n", count); 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, "allocations: %lu\n", allocations); 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"); return 0; }