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-rw-r--r--fs/nfsd/nfscache.c705
1 files changed, 705 insertions, 0 deletions
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
new file mode 100644
index 0000000000..6cd36af2f9
--- /dev/null
+++ b/fs/nfsd/nfscache.c
@@ -0,0 +1,705 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Request reply cache. This is currently a global cache, but this may
+ * change in the future and be a per-client cache.
+ *
+ * This code is heavily inspired by the 44BSD implementation, although
+ * it does things a bit differently.
+ *
+ * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/sunrpc/svc_xprt.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/sunrpc/addr.h>
+#include <linux/highmem.h>
+#include <linux/log2.h>
+#include <linux/hash.h>
+#include <net/checksum.h>
+
+#include "nfsd.h"
+#include "cache.h"
+#include "trace.h"
+
+/*
+ * We use this value to determine the number of hash buckets from the max
+ * cache size, the idea being that when the cache is at its maximum number
+ * of entries, then this should be the average number of entries per bucket.
+ */
+#define TARGET_BUCKET_SIZE 64
+
+struct nfsd_drc_bucket {
+ struct rb_root rb_head;
+ struct list_head lru_head;
+ spinlock_t cache_lock;
+};
+
+static struct kmem_cache *drc_slab;
+
+static int nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *vec);
+static unsigned long nfsd_reply_cache_count(struct shrinker *shrink,
+ struct shrink_control *sc);
+static unsigned long nfsd_reply_cache_scan(struct shrinker *shrink,
+ struct shrink_control *sc);
+
+/*
+ * Put a cap on the size of the DRC based on the amount of available
+ * low memory in the machine.
+ *
+ * 64MB: 8192
+ * 128MB: 11585
+ * 256MB: 16384
+ * 512MB: 23170
+ * 1GB: 32768
+ * 2GB: 46340
+ * 4GB: 65536
+ * 8GB: 92681
+ * 16GB: 131072
+ *
+ * ...with a hard cap of 256k entries. In the worst case, each entry will be
+ * ~1k, so the above numbers should give a rough max of the amount of memory
+ * used in k.
+ *
+ * XXX: these limits are per-container, so memory used will increase
+ * linearly with number of containers. Maybe that's OK.
+ */
+static unsigned int
+nfsd_cache_size_limit(void)
+{
+ unsigned int limit;
+ unsigned long low_pages = totalram_pages() - totalhigh_pages();
+
+ limit = (16 * int_sqrt(low_pages)) << (PAGE_SHIFT-10);
+ return min_t(unsigned int, limit, 256*1024);
+}
+
+/*
+ * Compute the number of hash buckets we need. Divide the max cachesize by
+ * the "target" max bucket size, and round up to next power of two.
+ */
+static unsigned int
+nfsd_hashsize(unsigned int limit)
+{
+ return roundup_pow_of_two(limit / TARGET_BUCKET_SIZE);
+}
+
+static struct nfsd_cacherep *
+nfsd_cacherep_alloc(struct svc_rqst *rqstp, __wsum csum,
+ struct nfsd_net *nn)
+{
+ struct nfsd_cacherep *rp;
+
+ rp = kmem_cache_alloc(drc_slab, GFP_KERNEL);
+ if (rp) {
+ rp->c_state = RC_UNUSED;
+ rp->c_type = RC_NOCACHE;
+ RB_CLEAR_NODE(&rp->c_node);
+ INIT_LIST_HEAD(&rp->c_lru);
+
+ memset(&rp->c_key, 0, sizeof(rp->c_key));
+ rp->c_key.k_xid = rqstp->rq_xid;
+ rp->c_key.k_proc = rqstp->rq_proc;
+ rpc_copy_addr((struct sockaddr *)&rp->c_key.k_addr, svc_addr(rqstp));
+ rpc_set_port((struct sockaddr *)&rp->c_key.k_addr, rpc_get_port(svc_addr(rqstp)));
+ rp->c_key.k_prot = rqstp->rq_prot;
+ rp->c_key.k_vers = rqstp->rq_vers;
+ rp->c_key.k_len = rqstp->rq_arg.len;
+ rp->c_key.k_csum = csum;
+ }
+ return rp;
+}
+
+static void nfsd_cacherep_free(struct nfsd_cacherep *rp)
+{
+ if (rp->c_type == RC_REPLBUFF)
+ kfree(rp->c_replvec.iov_base);
+ kmem_cache_free(drc_slab, rp);
+}
+
+static unsigned long
+nfsd_cacherep_dispose(struct list_head *dispose)
+{
+ struct nfsd_cacherep *rp;
+ unsigned long freed = 0;
+
+ while (!list_empty(dispose)) {
+ rp = list_first_entry(dispose, struct nfsd_cacherep, c_lru);
+ list_del(&rp->c_lru);
+ nfsd_cacherep_free(rp);
+ freed++;
+ }
+ return freed;
+}
+
+static void
+nfsd_cacherep_unlink_locked(struct nfsd_net *nn, struct nfsd_drc_bucket *b,
+ struct nfsd_cacherep *rp)
+{
+ if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base)
+ nfsd_stats_drc_mem_usage_sub(nn, rp->c_replvec.iov_len);
+ if (rp->c_state != RC_UNUSED) {
+ rb_erase(&rp->c_node, &b->rb_head);
+ list_del(&rp->c_lru);
+ atomic_dec(&nn->num_drc_entries);
+ nfsd_stats_drc_mem_usage_sub(nn, sizeof(*rp));
+ }
+}
+
+static void
+nfsd_reply_cache_free_locked(struct nfsd_drc_bucket *b, struct nfsd_cacherep *rp,
+ struct nfsd_net *nn)
+{
+ nfsd_cacherep_unlink_locked(nn, b, rp);
+ nfsd_cacherep_free(rp);
+}
+
+static void
+nfsd_reply_cache_free(struct nfsd_drc_bucket *b, struct nfsd_cacherep *rp,
+ struct nfsd_net *nn)
+{
+ spin_lock(&b->cache_lock);
+ nfsd_cacherep_unlink_locked(nn, b, rp);
+ spin_unlock(&b->cache_lock);
+ nfsd_cacherep_free(rp);
+}
+
+int nfsd_drc_slab_create(void)
+{
+ drc_slab = kmem_cache_create("nfsd_drc",
+ sizeof(struct nfsd_cacherep), 0, 0, NULL);
+ return drc_slab ? 0: -ENOMEM;
+}
+
+void nfsd_drc_slab_free(void)
+{
+ kmem_cache_destroy(drc_slab);
+}
+
+/**
+ * nfsd_net_reply_cache_init - per net namespace reply cache set-up
+ * @nn: nfsd_net being initialized
+ *
+ * Returns zero on succes; otherwise a negative errno is returned.
+ */
+int nfsd_net_reply_cache_init(struct nfsd_net *nn)
+{
+ return nfsd_percpu_counters_init(nn->counter, NFSD_NET_COUNTERS_NUM);
+}
+
+/**
+ * nfsd_net_reply_cache_destroy - per net namespace reply cache tear-down
+ * @nn: nfsd_net being freed
+ *
+ */
+void nfsd_net_reply_cache_destroy(struct nfsd_net *nn)
+{
+ nfsd_percpu_counters_destroy(nn->counter, NFSD_NET_COUNTERS_NUM);
+}
+
+int nfsd_reply_cache_init(struct nfsd_net *nn)
+{
+ unsigned int hashsize;
+ unsigned int i;
+ int status = 0;
+
+ nn->max_drc_entries = nfsd_cache_size_limit();
+ atomic_set(&nn->num_drc_entries, 0);
+ hashsize = nfsd_hashsize(nn->max_drc_entries);
+ nn->maskbits = ilog2(hashsize);
+
+ nn->nfsd_reply_cache_shrinker.scan_objects = nfsd_reply_cache_scan;
+ nn->nfsd_reply_cache_shrinker.count_objects = nfsd_reply_cache_count;
+ nn->nfsd_reply_cache_shrinker.seeks = 1;
+ status = register_shrinker(&nn->nfsd_reply_cache_shrinker,
+ "nfsd-reply:%s", nn->nfsd_name);
+ if (status)
+ return status;
+
+ nn->drc_hashtbl = kvzalloc(array_size(hashsize,
+ sizeof(*nn->drc_hashtbl)), GFP_KERNEL);
+ if (!nn->drc_hashtbl)
+ goto out_shrinker;
+
+ for (i = 0; i < hashsize; i++) {
+ INIT_LIST_HEAD(&nn->drc_hashtbl[i].lru_head);
+ spin_lock_init(&nn->drc_hashtbl[i].cache_lock);
+ }
+ nn->drc_hashsize = hashsize;
+
+ return 0;
+out_shrinker:
+ unregister_shrinker(&nn->nfsd_reply_cache_shrinker);
+ printk(KERN_ERR "nfsd: failed to allocate reply cache\n");
+ return -ENOMEM;
+}
+
+void nfsd_reply_cache_shutdown(struct nfsd_net *nn)
+{
+ struct nfsd_cacherep *rp;
+ unsigned int i;
+
+ unregister_shrinker(&nn->nfsd_reply_cache_shrinker);
+
+ for (i = 0; i < nn->drc_hashsize; i++) {
+ struct list_head *head = &nn->drc_hashtbl[i].lru_head;
+ while (!list_empty(head)) {
+ rp = list_first_entry(head, struct nfsd_cacherep, c_lru);
+ nfsd_reply_cache_free_locked(&nn->drc_hashtbl[i],
+ rp, nn);
+ }
+ }
+
+ kvfree(nn->drc_hashtbl);
+ nn->drc_hashtbl = NULL;
+ nn->drc_hashsize = 0;
+
+}
+
+/*
+ * Move cache entry to end of LRU list, and queue the cleaner to run if it's
+ * not already scheduled.
+ */
+static void
+lru_put_end(struct nfsd_drc_bucket *b, struct nfsd_cacherep *rp)
+{
+ rp->c_timestamp = jiffies;
+ list_move_tail(&rp->c_lru, &b->lru_head);
+}
+
+static noinline struct nfsd_drc_bucket *
+nfsd_cache_bucket_find(__be32 xid, struct nfsd_net *nn)
+{
+ unsigned int hash = hash_32((__force u32)xid, nn->maskbits);
+
+ return &nn->drc_hashtbl[hash];
+}
+
+/*
+ * Remove and return no more than @max expired entries in bucket @b.
+ * If @max is zero, do not limit the number of removed entries.
+ */
+static void
+nfsd_prune_bucket_locked(struct nfsd_net *nn, struct nfsd_drc_bucket *b,
+ unsigned int max, struct list_head *dispose)
+{
+ unsigned long expiry = jiffies - RC_EXPIRE;
+ struct nfsd_cacherep *rp, *tmp;
+ unsigned int freed = 0;
+
+ lockdep_assert_held(&b->cache_lock);
+
+ /* The bucket LRU is ordered oldest-first. */
+ list_for_each_entry_safe(rp, tmp, &b->lru_head, c_lru) {
+ /*
+ * Don't free entries attached to calls that are still
+ * in-progress, but do keep scanning the list.
+ */
+ if (rp->c_state == RC_INPROG)
+ continue;
+
+ if (atomic_read(&nn->num_drc_entries) <= nn->max_drc_entries &&
+ time_before(expiry, rp->c_timestamp))
+ break;
+
+ nfsd_cacherep_unlink_locked(nn, b, rp);
+ list_add(&rp->c_lru, dispose);
+
+ if (max && ++freed > max)
+ break;
+ }
+}
+
+/**
+ * nfsd_reply_cache_count - count_objects method for the DRC shrinker
+ * @shrink: our registered shrinker context
+ * @sc: garbage collection parameters
+ *
+ * Returns the total number of entries in the duplicate reply cache. To
+ * keep things simple and quick, this is not the number of expired entries
+ * in the cache (ie, the number that would be removed by a call to
+ * nfsd_reply_cache_scan).
+ */
+static unsigned long
+nfsd_reply_cache_count(struct shrinker *shrink, struct shrink_control *sc)
+{
+ struct nfsd_net *nn = container_of(shrink,
+ struct nfsd_net, nfsd_reply_cache_shrinker);
+
+ return atomic_read(&nn->num_drc_entries);
+}
+
+/**
+ * nfsd_reply_cache_scan - scan_objects method for the DRC shrinker
+ * @shrink: our registered shrinker context
+ * @sc: garbage collection parameters
+ *
+ * Free expired entries on each bucket's LRU list until we've released
+ * nr_to_scan freed objects. Nothing will be released if the cache
+ * has not exceeded it's max_drc_entries limit.
+ *
+ * Returns the number of entries released by this call.
+ */
+static unsigned long
+nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
+{
+ struct nfsd_net *nn = container_of(shrink,
+ struct nfsd_net, nfsd_reply_cache_shrinker);
+ unsigned long freed = 0;
+ LIST_HEAD(dispose);
+ unsigned int i;
+
+ for (i = 0; i < nn->drc_hashsize; i++) {
+ struct nfsd_drc_bucket *b = &nn->drc_hashtbl[i];
+
+ if (list_empty(&b->lru_head))
+ continue;
+
+ spin_lock(&b->cache_lock);
+ nfsd_prune_bucket_locked(nn, b, 0, &dispose);
+ spin_unlock(&b->cache_lock);
+
+ freed += nfsd_cacherep_dispose(&dispose);
+ if (freed > sc->nr_to_scan)
+ break;
+ }
+
+ trace_nfsd_drc_gc(nn, freed);
+ return freed;
+}
+
+/**
+ * nfsd_cache_csum - Checksum incoming NFS Call arguments
+ * @buf: buffer containing a whole RPC Call message
+ * @start: starting byte of the NFS Call header
+ * @remaining: size of the NFS Call header, in bytes
+ *
+ * Compute a weak checksum of the leading bytes of an NFS procedure
+ * call header to help verify that a retransmitted Call matches an
+ * entry in the duplicate reply cache.
+ *
+ * To avoid assumptions about how the RPC message is laid out in
+ * @buf and what else it might contain (eg, a GSS MIC suffix), the
+ * caller passes us the exact location and length of the NFS Call
+ * header.
+ *
+ * Returns a 32-bit checksum value, as defined in RFC 793.
+ */
+static __wsum nfsd_cache_csum(struct xdr_buf *buf, unsigned int start,
+ unsigned int remaining)
+{
+ unsigned int base, len;
+ struct xdr_buf subbuf;
+ __wsum csum = 0;
+ void *p;
+ int idx;
+
+ if (remaining > RC_CSUMLEN)
+ remaining = RC_CSUMLEN;
+ if (xdr_buf_subsegment(buf, &subbuf, start, remaining))
+ return csum;
+
+ /* rq_arg.head first */
+ if (subbuf.head[0].iov_len) {
+ len = min_t(unsigned int, subbuf.head[0].iov_len, remaining);
+ csum = csum_partial(subbuf.head[0].iov_base, len, csum);
+ remaining -= len;
+ }
+
+ /* Continue into page array */
+ idx = subbuf.page_base / PAGE_SIZE;
+ base = subbuf.page_base & ~PAGE_MASK;
+ while (remaining) {
+ p = page_address(subbuf.pages[idx]) + base;
+ len = min_t(unsigned int, PAGE_SIZE - base, remaining);
+ csum = csum_partial(p, len, csum);
+ remaining -= len;
+ base = 0;
+ ++idx;
+ }
+ return csum;
+}
+
+static int
+nfsd_cache_key_cmp(const struct nfsd_cacherep *key,
+ const struct nfsd_cacherep *rp, struct nfsd_net *nn)
+{
+ if (key->c_key.k_xid == rp->c_key.k_xid &&
+ key->c_key.k_csum != rp->c_key.k_csum) {
+ nfsd_stats_payload_misses_inc(nn);
+ trace_nfsd_drc_mismatch(nn, key, rp);
+ }
+
+ return memcmp(&key->c_key, &rp->c_key, sizeof(key->c_key));
+}
+
+/*
+ * Search the request hash for an entry that matches the given rqstp.
+ * Must be called with cache_lock held. Returns the found entry or
+ * inserts an empty key on failure.
+ */
+static struct nfsd_cacherep *
+nfsd_cache_insert(struct nfsd_drc_bucket *b, struct nfsd_cacherep *key,
+ struct nfsd_net *nn)
+{
+ struct nfsd_cacherep *rp, *ret = key;
+ struct rb_node **p = &b->rb_head.rb_node,
+ *parent = NULL;
+ unsigned int entries = 0;
+ int cmp;
+
+ while (*p != NULL) {
+ ++entries;
+ parent = *p;
+ rp = rb_entry(parent, struct nfsd_cacherep, c_node);
+
+ cmp = nfsd_cache_key_cmp(key, rp, nn);
+ if (cmp < 0)
+ p = &parent->rb_left;
+ else if (cmp > 0)
+ p = &parent->rb_right;
+ else {
+ ret = rp;
+ goto out;
+ }
+ }
+ rb_link_node(&key->c_node, parent, p);
+ rb_insert_color(&key->c_node, &b->rb_head);
+out:
+ /* tally hash chain length stats */
+ if (entries > nn->longest_chain) {
+ nn->longest_chain = entries;
+ nn->longest_chain_cachesize = atomic_read(&nn->num_drc_entries);
+ } else if (entries == nn->longest_chain) {
+ /* prefer to keep the smallest cachesize possible here */
+ nn->longest_chain_cachesize = min_t(unsigned int,
+ nn->longest_chain_cachesize,
+ atomic_read(&nn->num_drc_entries));
+ }
+
+ lru_put_end(b, ret);
+ return ret;
+}
+
+/**
+ * nfsd_cache_lookup - Find an entry in the duplicate reply cache
+ * @rqstp: Incoming Call to find
+ * @start: starting byte in @rqstp->rq_arg of the NFS Call header
+ * @len: size of the NFS Call header, in bytes
+ * @cacherep: OUT: DRC entry for this request
+ *
+ * Try to find an entry matching the current call in the cache. When none
+ * is found, we try to grab the oldest expired entry off the LRU list. If
+ * a suitable one isn't there, then drop the cache_lock and allocate a
+ * new one, then search again in case one got inserted while this thread
+ * didn't hold the lock.
+ *
+ * Return values:
+ * %RC_DOIT: Process the request normally
+ * %RC_REPLY: Reply from cache
+ * %RC_DROPIT: Do not process the request further
+ */
+int nfsd_cache_lookup(struct svc_rqst *rqstp, unsigned int start,
+ unsigned int len, struct nfsd_cacherep **cacherep)
+{
+ struct nfsd_net *nn;
+ struct nfsd_cacherep *rp, *found;
+ __wsum csum;
+ struct nfsd_drc_bucket *b;
+ int type = rqstp->rq_cachetype;
+ unsigned long freed;
+ LIST_HEAD(dispose);
+ int rtn = RC_DOIT;
+
+ if (type == RC_NOCACHE) {
+ nfsd_stats_rc_nocache_inc();
+ goto out;
+ }
+
+ csum = nfsd_cache_csum(&rqstp->rq_arg, start, len);
+
+ /*
+ * Since the common case is a cache miss followed by an insert,
+ * preallocate an entry.
+ */
+ nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+ rp = nfsd_cacherep_alloc(rqstp, csum, nn);
+ if (!rp)
+ goto out;
+
+ b = nfsd_cache_bucket_find(rqstp->rq_xid, nn);
+ spin_lock(&b->cache_lock);
+ found = nfsd_cache_insert(b, rp, nn);
+ if (found != rp)
+ goto found_entry;
+ *cacherep = rp;
+ rp->c_state = RC_INPROG;
+ nfsd_prune_bucket_locked(nn, b, 3, &dispose);
+ spin_unlock(&b->cache_lock);
+
+ freed = nfsd_cacherep_dispose(&dispose);
+ trace_nfsd_drc_gc(nn, freed);
+
+ nfsd_stats_rc_misses_inc();
+ atomic_inc(&nn->num_drc_entries);
+ nfsd_stats_drc_mem_usage_add(nn, sizeof(*rp));
+ goto out;
+
+found_entry:
+ /* We found a matching entry which is either in progress or done. */
+ nfsd_reply_cache_free_locked(NULL, rp, nn);
+ nfsd_stats_rc_hits_inc();
+ rtn = RC_DROPIT;
+ rp = found;
+
+ /* Request being processed */
+ if (rp->c_state == RC_INPROG)
+ goto out_trace;
+
+ /* From the hall of fame of impractical attacks:
+ * Is this a user who tries to snoop on the cache? */
+ rtn = RC_DOIT;
+ if (!test_bit(RQ_SECURE, &rqstp->rq_flags) && rp->c_secure)
+ goto out_trace;
+
+ /* Compose RPC reply header */
+ switch (rp->c_type) {
+ case RC_NOCACHE:
+ break;
+ case RC_REPLSTAT:
+ xdr_stream_encode_be32(&rqstp->rq_res_stream, rp->c_replstat);
+ rtn = RC_REPLY;
+ break;
+ case RC_REPLBUFF:
+ if (!nfsd_cache_append(rqstp, &rp->c_replvec))
+ goto out_unlock; /* should not happen */
+ rtn = RC_REPLY;
+ break;
+ default:
+ WARN_ONCE(1, "nfsd: bad repcache type %d\n", rp->c_type);
+ }
+
+out_trace:
+ trace_nfsd_drc_found(nn, rqstp, rtn);
+out_unlock:
+ spin_unlock(&b->cache_lock);
+out:
+ return rtn;
+}
+
+/**
+ * nfsd_cache_update - Update an entry in the duplicate reply cache.
+ * @rqstp: svc_rqst with a finished Reply
+ * @rp: IN: DRC entry for this request
+ * @cachetype: which cache to update
+ * @statp: pointer to Reply's NFS status code, or NULL
+ *
+ * This is called from nfsd_dispatch when the procedure has been
+ * executed and the complete reply is in rqstp->rq_res.
+ *
+ * We're copying around data here rather than swapping buffers because
+ * the toplevel loop requires max-sized buffers, which would be a waste
+ * of memory for a cache with a max reply size of 100 bytes (diropokres).
+ *
+ * If we should start to use different types of cache entries tailored
+ * specifically for attrstat and fh's, we may save even more space.
+ *
+ * Also note that a cachetype of RC_NOCACHE can legally be passed when
+ * nfsd failed to encode a reply that otherwise would have been cached.
+ * In this case, nfsd_cache_update is called with statp == NULL.
+ */
+void nfsd_cache_update(struct svc_rqst *rqstp, struct nfsd_cacherep *rp,
+ int cachetype, __be32 *statp)
+{
+ struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+ struct kvec *resv = &rqstp->rq_res.head[0], *cachv;
+ struct nfsd_drc_bucket *b;
+ int len;
+ size_t bufsize = 0;
+
+ if (!rp)
+ return;
+
+ b = nfsd_cache_bucket_find(rp->c_key.k_xid, nn);
+
+ len = resv->iov_len - ((char*)statp - (char*)resv->iov_base);
+ len >>= 2;
+
+ /* Don't cache excessive amounts of data and XDR failures */
+ if (!statp || len > (256 >> 2)) {
+ nfsd_reply_cache_free(b, rp, nn);
+ return;
+ }
+
+ switch (cachetype) {
+ case RC_REPLSTAT:
+ if (len != 1)
+ printk("nfsd: RC_REPLSTAT/reply len %d!\n",len);
+ rp->c_replstat = *statp;
+ break;
+ case RC_REPLBUFF:
+ cachv = &rp->c_replvec;
+ bufsize = len << 2;
+ cachv->iov_base = kmalloc(bufsize, GFP_KERNEL);
+ if (!cachv->iov_base) {
+ nfsd_reply_cache_free(b, rp, nn);
+ return;
+ }
+ cachv->iov_len = bufsize;
+ memcpy(cachv->iov_base, statp, bufsize);
+ break;
+ case RC_NOCACHE:
+ nfsd_reply_cache_free(b, rp, nn);
+ return;
+ }
+ spin_lock(&b->cache_lock);
+ nfsd_stats_drc_mem_usage_add(nn, bufsize);
+ lru_put_end(b, rp);
+ rp->c_secure = test_bit(RQ_SECURE, &rqstp->rq_flags);
+ rp->c_type = cachetype;
+ rp->c_state = RC_DONE;
+ spin_unlock(&b->cache_lock);
+ return;
+}
+
+static int
+nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *data)
+{
+ __be32 *p;
+
+ p = xdr_reserve_space(&rqstp->rq_res_stream, data->iov_len);
+ if (unlikely(!p))
+ return false;
+ memcpy(p, data->iov_base, data->iov_len);
+ xdr_commit_encode(&rqstp->rq_res_stream);
+ return true;
+}
+
+/*
+ * 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_reply_cache_stats_show(struct seq_file *m, void *v)
+{
+ struct nfsd_net *nn = net_generic(file_inode(m->file)->i_sb->s_fs_info,
+ nfsd_net_id);
+
+ seq_printf(m, "max entries: %u\n", nn->max_drc_entries);
+ seq_printf(m, "num entries: %u\n",
+ atomic_read(&nn->num_drc_entries));
+ seq_printf(m, "hash buckets: %u\n", 1 << nn->maskbits);
+ seq_printf(m, "mem usage: %lld\n",
+ percpu_counter_sum_positive(&nn->counter[NFSD_NET_DRC_MEM_USAGE]));
+ seq_printf(m, "cache hits: %lld\n",
+ percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_RC_HITS]));
+ seq_printf(m, "cache misses: %lld\n",
+ percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_RC_MISSES]));
+ seq_printf(m, "not cached: %lld\n",
+ percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_RC_NOCACHE]));
+ seq_printf(m, "payload misses: %lld\n",
+ percpu_counter_sum_positive(&nn->counter[NFSD_NET_PAYLOAD_MISSES]));
+ seq_printf(m, "longest chain len: %u\n", nn->longest_chain);
+ seq_printf(m, "cachesize at longest: %u\n", nn->longest_chain_cachesize);
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-28 18:09:24 +0000