Merge branch 'for-3.10' of git://linux-nfs.org/~bfields/linux

Pull nfsd changes from J Bruce Fields:
 "Highlights include:

   - Some more DRC cleanup and performance work from Jeff Layton

   - A gss-proxy upcall from Simo Sorce: currently krb5 mounts to the
     server using credentials from Active Directory often fail due to
     limitations of the svcgssd upcall interface.  This replacement
     lifts those limitations.  The existing upcall is still supported
     for backwards compatibility.

   - More NFSv4.1 support: at this point, if a user with a current
     client who upgrades from 4.0 to 4.1 should see no regressions.  In
     theory we do everything a 4.1 server is required to do.  Patches
     for a couple minor exceptions are ready for 3.11, and with those
     and some more testing I'd like to turn 4.1 on by default in 3.11."

Fix up semantic conflict as per Stephen Rothwell and linux-next:

Commit 030d794bf498 ("SUNRPC: Use gssproxy upcall for server RPCGSS
authentication") adds two new users of "PDE(inode)->data", but we're
supposed to use "PDE_DATA(inode)" instead since commit d9dda78bad87
("procfs: new helper - PDE_DATA(inode)").

The old PDE() macro is no longer available since commit c30480b92cf4
("proc: Make the PROC_I() and PDE() macros internal to procfs")

* 'for-3.10' of git://linux-nfs.org/~bfields/linux: (60 commits)
  NFSD: SECINFO doesn't handle unsupported pseudoflavors correctly
  NFSD: Simplify GSS flavor encoding in nfsd4_do_encode_secinfo()
  nfsd: make symbol nfsd_reply_cache_shrinker static
  svcauth_gss: fix error return code in rsc_parse()
  nfsd4: don't remap EISDIR errors in rename
  svcrpc: fix gss-proxy to respect user namespaces
  SUNRPC: gssp_procedures[] can be static
  SUNRPC: define {create,destroy}_use_gss_proxy_proc_entry in !PROC case
  nfsd4: better error return to indicate SSV non-support
  nfsd: fix EXDEV checking in rename
  SUNRPC: Use gssproxy upcall for server RPCGSS authentication.
  SUNRPC: Add RPC based upcall mechanism for RPCGSS auth
  SUNRPC: conditionally return endtime from import_sec_context
  SUNRPC: allow disabling idle timeout
  SUNRPC: attempt AF_LOCAL connect on setup
  nfsd: Decode and send 64bit time values
  nfsd4: put_client_renew_locked can be static
  nfsd4: remove unused macro
  nfsd4: remove some useless code
  nfsd4: implement SEQ4_STATUS_RECALLABLE_STATE_REVOKED
  ...

1 files changed, 146 insertions, 51 deletions

diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index ca05f6dc3544..e76244edd748 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -11,6 +11,8 @@
 #include <linux/slab.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"
@@ -18,30 +20,49 @@
 
 #define NFSDDBG_FACILITY	NFSDDBG_REPCACHE
 
-#define HASHSIZE		64
+/*
+ * 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
 
 static struct hlist_head *	cache_hash;
 static struct list_head 	lru_head;
 static struct kmem_cache	*drc_slab;
-static unsigned int		num_drc_entries;
+
+/* max number of entries allowed in the cache */
 static unsigned int		max_drc_entries;
 
+/* number of significant bits in the hash value */
+static unsigned int		maskbits;
+
 /*
- * Calculate the hash index from an XID.
+ * Stats and other tracking of on the duplicate reply cache. All of these and
+ * the "rc" fields in nfsdstats are protected by the cache_lock
  */
-static inline u32 request_hash(u32 xid)
-{
-	u32 h = xid;
-	h ^= (xid >> 24);
-	return h & (HASHSIZE-1);
-}
+
+/* total number of entries */
+static unsigned int		num_drc_entries;
+
+/* cache misses due only to checksum comparison failures */
+static unsigned int		payload_misses;
+
+/* amount of memory (in bytes) currently consumed by the DRC */
+static unsigned int		drc_mem_usage;
+
+/* longest hash chain seen */
+static unsigned int		longest_chain;
+
+/* size of cache when we saw the longest hash chain */
+static unsigned int		longest_chain_cachesize;
 
 static int	nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *vec);
 static void	cache_cleaner_func(struct work_struct *unused);
 static int 	nfsd_reply_cache_shrink(struct shrinker *shrink,
 					struct shrink_control *sc);
 
-struct shrinker nfsd_reply_cache_shrinker = {
+static struct shrinker nfsd_reply_cache_shrinker = {
 	.shrink	= nfsd_reply_cache_shrink,
 	.seeks	= 1,
 };
@@ -82,6 +103,16 @@ nfsd_cache_size_limit(void)
 	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 svc_cacherep *
 nfsd_reply_cache_alloc(void)
 {
@@ -100,12 +131,15 @@ nfsd_reply_cache_alloc(void)
 static void
 nfsd_reply_cache_free_locked(struct svc_cacherep *rp)
 {
-	if (rp->c_type == RC_REPLBUFF)
+	if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base) {
+		drc_mem_usage -= rp->c_replvec.iov_len;
 		kfree(rp->c_replvec.iov_base);
+	}
 	if (!hlist_unhashed(&rp->c_hash))
 		hlist_del(&rp->c_hash);
 	list_del(&rp->c_lru);
 	--num_drc_entries;
+	drc_mem_usage -= sizeof(*rp);
 	kmem_cache_free(drc_slab, rp);
 }
 
@@ -119,9 +153,13 @@ nfsd_reply_cache_free(struct svc_cacherep *rp)
 
 int nfsd_reply_cache_init(void)
 {
+	unsigned int hashsize;
+
 	INIT_LIST_HEAD(&lru_head);
 	max_drc_entries = nfsd_cache_size_limit();
 	num_drc_entries = 0;
+	hashsize = nfsd_hashsize(max_drc_entries);
+	maskbits = ilog2(hashsize);
 
 	register_shrinker(&nfsd_reply_cache_shrinker);
 	drc_slab = kmem_cache_create("nfsd_drc", sizeof(struct svc_cacherep),
@@ -129,7 +167,7 @@ int nfsd_reply_cache_init(void)
 	if (!drc_slab)
 		goto out_nomem;
 
-	cache_hash = kcalloc(HASHSIZE, sizeof(struct hlist_head), GFP_KERNEL);
+	cache_hash = kcalloc(hashsize, sizeof(struct hlist_head), GFP_KERNEL);
 	if (!cache_hash)
 		goto out_nomem;
 
@@ -180,7 +218,7 @@ static void
 hash_refile(struct svc_cacherep *rp)
 {
 	hlist_del_init(&rp->c_hash);
-	hlist_add_head(&rp->c_hash, cache_hash + request_hash(rp->c_xid));
+	hlist_add_head(&rp->c_hash, cache_hash + hash_32(rp->c_xid, maskbits));
 }
 
 static inline bool
@@ -273,6 +311,26 @@ nfsd_cache_csum(struct svc_rqst *rqstp)
 	return csum;
 }
 
+static bool
+nfsd_cache_match(struct svc_rqst *rqstp, __wsum csum, struct svc_cacherep *rp)
+{
+	/* Check RPC header info first */
+	if (rqstp->rq_xid != rp->c_xid || rqstp->rq_proc != rp->c_proc ||
+	    rqstp->rq_prot != rp->c_prot || rqstp->rq_vers != rp->c_vers ||
+	    rqstp->rq_arg.len != rp->c_len ||
+	    !rpc_cmp_addr(svc_addr(rqstp), (struct sockaddr *)&rp->c_addr) ||
+	    rpc_get_port(svc_addr(rqstp)) != rpc_get_port((struct sockaddr *)&rp->c_addr))
+		return false;
+
+	/* compare checksum of NFS data */
+	if (csum != rp->c_csum) {
+		++payload_misses;
+		return false;
+	}
+
+	return true;
+}
+
 /*
  * Search the request hash for an entry that matches the given rqstp.
  * Must be called with cache_lock held. Returns the found entry or
@@ -281,23 +339,30 @@ nfsd_cache_csum(struct svc_rqst *rqstp)
 static struct svc_cacherep *
 nfsd_cache_search(struct svc_rqst *rqstp, __wsum csum)
 {
-	struct svc_cacherep	*rp;
+	struct svc_cacherep	*rp, *ret = NULL;
 	struct hlist_head 	*rh;
-	__be32			xid = rqstp->rq_xid;
-	u32			proto =  rqstp->rq_prot,
-				vers = rqstp->rq_vers,
-				proc = rqstp->rq_proc;
+	unsigned int		entries = 0;
 
-	rh = &cache_hash[request_hash(xid)];
+	rh = &cache_hash[hash_32(rqstp->rq_xid, maskbits)];
 	hlist_for_each_entry(rp, rh, c_hash) {
-		if (xid == rp->c_xid && proc == rp->c_proc &&
-		    proto == rp->c_prot && vers == rp->c_vers &&
-		    rqstp->rq_arg.len == rp->c_len && csum == rp->c_csum &&
-		    rpc_cmp_addr(svc_addr(rqstp), (struct sockaddr *)&rp->c_addr) &&
-		    rpc_get_port(svc_addr(rqstp)) == rpc_get_port((struct sockaddr *)&rp->c_addr))
-			return rp;
+		++entries;
+		if (nfsd_cache_match(rqstp, csum, rp)) {
+			ret = rp;
+			break;
+		}
 	}
-	return NULL;
+
+	/* tally hash chain length stats */
+	if (entries > longest_chain) {
+		longest_chain = entries;
+		longest_chain_cachesize = num_drc_entries;
+	} else if (entries == longest_chain) {
+		/* prefer to keep the smallest cachesize possible here */
+		longest_chain_cachesize = min(longest_chain_cachesize,
+						num_drc_entries);
+	}
+
+	return ret;
 }
 
 /*
@@ -318,55 +383,55 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
 	__wsum			csum;
 	unsigned long		age;
 	int type = rqstp->rq_cachetype;
-	int rtn;
+	int rtn = RC_DOIT;
 
 	rqstp->rq_cacherep = NULL;
 	if (type == RC_NOCACHE) {
 		nfsdstats.rcnocache++;
-		return RC_DOIT;
+		return rtn;
 	}
 
 	csum = nfsd_cache_csum(rqstp);
 
+	/*
+	 * Since the common case is a cache miss followed by an insert,
+	 * preallocate an entry. First, try to reuse the first entry on the LRU
+	 * if it works, then go ahead and prune the LRU list.
+	 */
 	spin_lock(&cache_lock);
-	rtn = RC_DOIT;
-
-	rp = nfsd_cache_search(rqstp, csum);
-	if (rp)
-		goto found_entry;
-
-	/* Try to use the first entry on the LRU */
 	if (!list_empty(&lru_head)) {
 		rp = list_first_entry(&lru_head, struct svc_cacherep, c_lru);
 		if (nfsd_cache_entry_expired(rp) ||
 		    num_drc_entries >= max_drc_entries) {
 			lru_put_end(rp);
 			prune_cache_entries();
-			goto setup_entry;
+			goto search_cache;
 		}
 	}
 
-	/* Drop the lock and allocate a new entry */
+	/* No expired ones available, allocate a new one. */
 	spin_unlock(&cache_lock);
 	rp = nfsd_reply_cache_alloc();
-	if (!rp) {
-		dprintk("nfsd: unable to allocate DRC entry!\n");
-		return RC_DOIT;
-	}
 	spin_lock(&cache_lock);
-	++num_drc_entries;
+	if (likely(rp)) {
+		++num_drc_entries;
+		drc_mem_usage += sizeof(*rp);
+	}
 
-	/*
-	 * Must search again just in case someone inserted one
-	 * after we dropped the lock above.
-	 */
+search_cache:
 	found = nfsd_cache_search(rqstp, csum);
 	if (found) {
-		nfsd_reply_cache_free_locked(rp);
+		if (likely(rp))
+			nfsd_reply_cache_free_locked(rp);
 		rp = found;
 		goto found_entry;
 	}
 
+	if (!rp) {
+		dprintk("nfsd: unable to allocate DRC entry!\n");
+		goto out;
+	}
+
 	/*
 	 * We're keeping the one we just allocated. Are we now over the
 	 * limit? Prune one off the tip of the LRU in trade for the one we
@@ -376,7 +441,6 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
 		nfsd_reply_cache_free_locked(list_first_entry(&lru_head,
 						struct svc_cacherep, c_lru));
 
-setup_entry:
 	nfsdstats.rcmisses++;
 	rqstp->rq_cacherep = rp;
 	rp->c_state = RC_INPROG;
@@ -394,6 +458,7 @@ setup_entry:
 
 	/* release any buffer */
 	if (rp->c_type == RC_REPLBUFF) {
+		drc_mem_usage -= rp->c_replvec.iov_len;
 		kfree(rp->c_replvec.iov_base);
 		rp->c_replvec.iov_base = NULL;
 	}
@@ -462,6 +527,7 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
 	struct svc_cacherep *rp = rqstp->rq_cacherep;
 	struct kvec	*resv = &rqstp->rq_res.head[0], *cachv;
 	int		len;
+	size_t		bufsize = 0;
 
 	if (!rp)
 		return;
@@ -483,19 +549,21 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
 		break;
 	case RC_REPLBUFF:
 		cachv = &rp->c_replvec;
-		cachv->iov_base = kmalloc(len << 2, GFP_KERNEL);
+		bufsize = len << 2;
+		cachv->iov_base = kmalloc(bufsize, GFP_KERNEL);
 		if (!cachv->iov_base) {
 			nfsd_reply_cache_free(rp);
 			return;
 		}
-		cachv->iov_len = len << 2;
-		memcpy(cachv->iov_base, statp, len << 2);
+		cachv->iov_len = bufsize;
+		memcpy(cachv->iov_base, statp, bufsize);
 		break;
 	case RC_NOCACHE:
 		nfsd_reply_cache_free(rp);
 		return;
 	}
 	spin_lock(&cache_lock);
+	drc_mem_usage += bufsize;
 	lru_put_end(rp);
 	rp->c_secure = rqstp->rq_secure;
 	rp->c_type = cachetype;
@@ -523,3 +591,30 @@ nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *data)
 	vec->iov_len += data->iov_len;
 	return 1;
 }
+
+/*
+ * 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.
+ */
+static int nfsd_reply_cache_stats_show(struct seq_file *m, void *v)
+{
+	spin_lock(&cache_lock);
+	seq_printf(m, "max entries:           %u\n", max_drc_entries);
+	seq_printf(m, "num entries:           %u\n", num_drc_entries);
+	seq_printf(m, "hash buckets:          %u\n", 1 << maskbits);
+	seq_printf(m, "mem usage:             %u\n", drc_mem_usage);
+	seq_printf(m, "cache hits:            %u\n", nfsdstats.rchits);
+	seq_printf(m, "cache misses:          %u\n", nfsdstats.rcmisses);
+	seq_printf(m, "not cached:            %u\n", nfsdstats.rcnocache);
+	seq_printf(m, "payload misses:        %u\n", payload_misses);
+	seq_printf(m, "longest chain len:     %u\n", longest_chain);
+	seq_printf(m, "cachesize at longest:  %u\n", longest_chain_cachesize);
+	spin_unlock(&cache_lock);
+	return 0;
+}
+
+int nfsd_reply_cache_stats_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, nfsd_reply_cache_stats_show, NULL);
+}