Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1276 insertions, 0 deletions

diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
new file mode 100644
index 000000000..5cb8cce15
--- /dev/null
+++ b/fs/nfsd/filecache.c
@@ -0,0 +1,1276 @@
+/*
+ * Open file cache.
+ *
+ * (c) 2015 - Jeff Layton <jeff.layton@primarydata.com>
+ */
+
+#include <linux/hash.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/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 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;
+	bool				gc;
+	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;
+}
+
+/**
+ * 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_GC, &nf->nf_flags) != key->gc)
+			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)
+{
+	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,
+			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 nfsd_file_lookup_key *key, unsigned int may)
+{
+	struct nfsd_file *nf;
+
+	nf = kmem_cache_alloc(nfsd_file_slab, GFP_KERNEL);
+	if (nf) {
+		INIT_LIST_HEAD(&nf->nf_lru);
+		nf->nf_birthtime = ktime_get();
+		nf->nf_file = NULL;
+		nf->nf_cred = get_current_cred();
+		nf->nf_net = key->net;
+		nf->nf_flags = 0;
+		__set_bit(NFSD_FILE_HASHED, &nf->nf_flags);
+		__set_bit(NFSD_FILE_PENDING, &nf->nf_flags);
+		if (key->gc)
+			__set_bit(NFSD_FILE_GC, &nf->nf_flags);
+		nf->nf_inode = key->inode;
+		refcount_set(&nf->nf_ref, 1);
+		nf->nf_may = key->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);
+	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_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) {
+		get_file(nf->nf_file);
+		filp_close(nf->nf_file, NULL);
+		nfsd_file_check_write_error(nf);
+		fput(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;
+
+	if (!file || !(file->f_mode & FMODE_WRITE))
+		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 (likely(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);
+	}
+}
+
+static void
+nfsd_file_list_remove_disposal(struct list_head *dst,
+		struct nfsd_fcache_disposal *l)
+{
+	spin_lock(&l->lock);
+	list_splice_init(&l->freeme, dst);
+	spin_unlock(&l->lock);
+}
+
+static void
+nfsd_file_list_add_disposal(struct list_head *files, struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct nfsd_fcache_disposal *l = nn->fcache_disposal;
+
+	spin_lock(&l->lock);
+	list_splice_tail_init(files, &l->freeme);
+	spin_unlock(&l->lock);
+	queue_work(nfsd_filecache_wq, &l->work);
+}
+
+static void
+nfsd_file_list_add_pernet(struct list_head *dst, struct list_head *src,
+		struct net *net)
+{
+	struct nfsd_file *nf, *tmp;
+
+	list_for_each_entry_safe(nf, tmp, src, nf_lru) {
+		if (nf->nf_net == net)
+			list_move_tail(&nf->nf_lru, dst);
+	}
+}
+
+static void
+nfsd_file_dispose_list_delayed(struct list_head *dispose)
+{
+	LIST_HEAD(list);
+	struct nfsd_file *nf;
+
+	while(!list_empty(dispose)) {
+		nf = list_first_entry(dispose, struct nfsd_file, nf_lru);
+		nfsd_file_list_add_pernet(&list, dispose, nf->nf_net);
+		nfsd_file_list_add_disposal(&list, nf->nf_net);
+	}
+}
+
+/**
+ * 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();
+	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 nfsd_file_lookup_key key = {
+		.type	= NFSD_FILE_KEY_INODE,
+		.inode	= inode,
+	};
+	struct nfsd_file *nf;
+
+	rcu_read_lock();
+	do {
+		nf = rhashtable_lookup(&nfsd_file_rhash_tbl, &key,
+				       nfsd_file_rhash_params);
+		if (!nf)
+			break;
+		nfsd_file_cond_queue(nf, dispose);
+	} while (1);
+	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
+ *
+ * Walk the LRU list and destroy any entries that have not been used since
+ * the last scan.
+ */
+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);
+
+	nfsd_file_list_remove_disposal(&head, l);
+	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 = 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_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;
+	rhashtable_destroy(&nfsd_file_rhash_tbl);
+	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.
+ */
+static void
+__nfsd_file_cache_purge(struct net *net)
+{
+	struct rhashtable_iter iter;
+	struct nfsd_file *nf;
+	LIST_HEAD(dispose);
+
+	rhashtable_walk_enter(&nfsd_file_rhash_tbl, &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;
+	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_evictions, i) = 0;
+	}
+}
+
+/**
+ * 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 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;
+}
+
+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)
+{
+	struct nfsd_file_lookup_key key = {
+		.type	= NFSD_FILE_KEY_FULL,
+		.need	= may_flags & NFSD_FILE_MAY_MASK,
+		.net	= SVC_NET(rqstp),
+		.gc	= want_gc,
+	};
+	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();
+
+retry:
+	rcu_read_lock();
+	nf = rhashtable_lookup(&nfsd_file_rhash_tbl, &key,
+			       nfsd_file_rhash_params);
+	if (nf)
+		nf = nfsd_file_get(nf);
+	rcu_read_unlock();
+
+	if (nf) {
+		if (nfsd_file_lru_remove(nf))
+			WARN_ON_ONCE(refcount_dec_and_test(&nf->nf_ref));
+		goto wait_for_construction;
+	}
+
+	nf = nfsd_file_alloc(&key, may_flags);
+	if (!nf) {
+		status = nfserr_jukebox;
+		goto out_status;
+	}
+
+	ret = rhashtable_lookup_insert_key(&nfsd_file_rhash_tbl,
+					   &key, &nf->nf_rhash,
+					   nfsd_file_rhash_params);
+	if (likely(ret == 0))
+		goto open_file;
+
+	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)) {
+		trace_nfsd_file_cons_err(rqstp, key.inode, may_flags, nf);
+		if (!open_retry) {
+			status = nfserr_jukebox;
+			goto out;
+		}
+		open_retry = false;
+		if (refcount_dec_and_test(&nf->nf_ref))
+			nfsd_file_free(nf);
+		goto retry;
+	}
+
+	this_cpu_inc(nfsd_file_cache_hits);
+
+	status = nfserrno(nfsd_open_break_lease(file_inode(nf->nf_file), may_flags));
+out:
+	if (status == nfs_ok) {
+		this_cpu_inc(nfsd_file_acquisitions);
+		nfsd_file_check_write_error(nf);
+		*pnf = nf;
+	} else {
+		if (refcount_dec_and_test(&nf->nf_ref))
+			nfsd_file_free(nf);
+		nf = NULL;
+	}
+
+out_status:
+	put_cred(key.cred);
+	trace_nfsd_file_acquire(rqstp, key.inode, may_flags, nf, status);
+	return status;
+
+open_file:
+	trace_nfsd_file_alloc(nf);
+	nf->nf_mark = nfsd_file_mark_find_or_create(nf, key.inode);
+	if (nf->nf_mark) {
+		if (file) {
+			get_file(file);
+			nf->nf_file = file;
+			status = nfs_ok;
+			trace_nfsd_file_opened(nf, status);
+		} else {
+			status = nfsd_open_verified(rqstp, fhp, may_flags,
+						    &nf->nf_file);
+			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 && key.inode->i_nlink == 0)
+		status = nfserr_jukebox;
+	if (status != nfs_ok)
+		nfsd_file_unhash(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_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.
+ *
+ * Returns nfs_ok and sets @pnf on success; otherwise an nfsstat 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().
+ *
+ * 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, 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.
+ *
+ * Returns nfs_ok and sets @pnf on success; otherwise an nfsstat 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_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) {
+		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 entries: %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;
+}