diff options
Diffstat (limited to 'fs/nfsd/filecache.c')
| -rw-r--r-- | fs/nfsd/filecache.c | 1249 |
1 files changed, 1249 insertions, 0 deletions
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c new file mode 100644 index 0000000000..07bf219f9a --- /dev/null +++ b/fs/nfsd/filecache.c @@ -0,0 +1,1249 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * The NFSD open file cache. + * + * (c) 2015 - Jeff Layton <jeff.layton@primarydata.com> + * + * 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 <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" +#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) + +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_evictions); + +struct nfsd_fcache_disposal { + struct work_struct work; + spinlock_t lock; + struct list_head freeme; +}; + +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 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_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, 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_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)); + 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; + + 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_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); + filp_close(nf->nf_file, NULL); + } + + /* + * 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(&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(&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); +} + +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_lru); + list_del_init(&nf->nf_lru); + 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_lru); + 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_lru, &l->freeme); + spin_unlock(&l->lock); + queue_work(nfsd_filecache_wq, &l->work); + } +} + +/** + * 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, + spinlock_t *lock, void *arg) + __releases(lock) + __acquires(lock) +{ + 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_move(lru, &nf->nf_lru, 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 = { + .scan_objects = nfsd_file_lru_scan, + .count_objects = nfsd_file_lru_count, + .seeks = 1, +}; + +/** + * 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_lru, 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_lru); + list_del_init(&nf->nf_lru); + nfsd_file_free(nf); + } + flush_delayed_fput(); +} + +/** + * nfsd_file_delayed_close - close unused nfsd_files + * @work: dummy + * + * Scrape the freeme list for this nfsd_net, and then dispose of them + * all. + */ +static void +nfsd_file_delayed_close(struct work_struct *work) +{ + LIST_HEAD(head); + struct nfsd_fcache_disposal *l = container_of(work, + struct nfsd_fcache_disposal, work); + + spin_lock(&l->lock); + list_splice_init(&l->freeme, &head); + spin_unlock(&l->lock); + + nfsd_file_dispose_list(&head); +} + +static int +nfsd_file_lease_notifier_call(struct notifier_block *nb, unsigned long arg, + void *data) +{ + struct file_lock *fl = data; + + /* Only close files for F_SETLEASE leases */ + if (fl->fl_flags & FL_LEASE) + nfsd_file_close_inode(file_inode(fl->fl_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) + return ret; + + ret = -ENOMEM; + nfsd_filecache_wq = alloc_workqueue("nfsd_filecache", 0, 0); + if (!nfsd_filecache_wq) + goto out; + + nfsd_file_slab = kmem_cache_create("nfsd_file", + sizeof(struct nfsd_file), 0, 0, NULL); + if (!nfsd_file_slab) { + pr_err("nfsd: unable to create nfsd_file_slab\n"); + goto out_err; + } + + nfsd_file_mark_slab = kmem_cache_create("nfsd_file_mark", + sizeof(struct nfsd_file_mark), 0, 0, NULL); + 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; + } + + 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; + } + + 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, + 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)); + 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: + return ret; +out_notifier: + lease_unregister_notifier(&nfsd_file_lease_notifier); +out_shrinker: + unregister_shrinker(&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; + destroy_workqueue(nfsd_filecache_wq); + nfsd_filecache_wq = 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; + INIT_WORK(&l->work, nfsd_file_delayed_close); + spin_lock_init(&l->lock); + INIT_LIST_HEAD(&l->freeme); + return l; +} + +static void +nfsd_free_fcache_disposal(struct nfsd_fcache_disposal *l) +{ + cancel_work_sync(&l->work); + 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); + unregister_shrinker(&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; + destroy_workqueue(nfsd_filecache_wq); + nfsd_filecache_wq = 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_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 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 net *net = SVC_NET(rqstp); + struct nfsd_file *new, *nf; + bool stale_retry = true; + bool open_retry = true; + struct inode *inode; + __be32 status; + int ret; + +retry: + status = fh_verify(rqstp, 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)) + WARN_ON_ONCE(refcount_dec_and_test(&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_slab_free(&new->nf_rcu); + 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; + + if (ret == -EEXIST) + goto retry; + 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; + } + 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(nf, 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(rqstp, 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, 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, fhp, may_flags, NULL, pnf, false); +} + +/** + * 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, 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 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); + 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, "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; +} |