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-rw-r--r--fs/nfsd/filecache.c1276
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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-14 17:59:35 +0000