1 files changed, 378 insertions, 255 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 75cb1cbe4cde..c6b263b5faf1 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -39,6 +39,7 @@
 #include <linux/sched.h>
 #include <linux/kmemleak.h>
 #include <linux/xattr.h>
+#include <linux/hash.h>
 
 #include "delegation.h"
 #include "iostat.h"
@@ -69,26 +70,26 @@ const struct address_space_operations nfs_dir_aops = {
 	.freepage = nfs_readdir_clear_array,
 };
 
-static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir)
+#define NFS_INIT_DTSIZE PAGE_SIZE
+
+static struct nfs_open_dir_context *
+alloc_nfs_open_dir_context(struct inode *dir)
 {
 	struct nfs_inode *nfsi = NFS_I(dir);
 	struct nfs_open_dir_context *ctx;
-	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
 	if (ctx != NULL) {
-		ctx->duped = 0;
 		ctx->attr_gencount = nfsi->attr_gencount;
-		ctx->dir_cookie = 0;
-		ctx->dup_cookie = 0;
-		ctx->page_index = 0;
-		ctx->eof = false;
+		ctx->dtsize = NFS_INIT_DTSIZE;
 		spin_lock(&dir->i_lock);
 		if (list_empty(&nfsi->open_files) &&
 		    (nfsi->cache_validity & NFS_INO_DATA_INVAL_DEFER))
 			nfs_set_cache_invalid(dir,
 					      NFS_INO_INVALID_DATA |
 						      NFS_INO_REVAL_FORCED);
-		list_add(&ctx->list, &nfsi->open_files);
-		clear_bit(NFS_INO_FORCE_READDIR, &nfsi->flags);
+		list_add_tail_rcu(&ctx->list, &nfsi->open_files);
+		memcpy(ctx->verf, nfsi->cookieverf, sizeof(ctx->verf));
 		spin_unlock(&dir->i_lock);
 		return ctx;
 	}
@@ -98,9 +99,9 @@ static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir
 static void put_nfs_open_dir_context(struct inode *dir, struct nfs_open_dir_context *ctx)
 {
 	spin_lock(&dir->i_lock);
-	list_del(&ctx->list);
+	list_del_rcu(&ctx->list);
 	spin_unlock(&dir->i_lock);
-	kfree(ctx);
+	kfree_rcu(ctx, rcu_head);
 }
 
 /*
@@ -142,6 +143,7 @@ struct nfs_cache_array_entry {
 };
 
 struct nfs_cache_array {
+	u64 change_attr;
 	u64 last_cookie;
 	unsigned int size;
 	unsigned char page_full : 1,
@@ -155,11 +157,10 @@ struct nfs_readdir_descriptor {
 	struct page	*page;
 	struct dir_context *ctx;
 	pgoff_t		page_index;
+	pgoff_t		page_index_max;
 	u64		dir_cookie;
 	u64		last_cookie;
-	u64		dup_cookie;
 	loff_t		current_index;
-	loff_t		prev_index;
 
 	__be32		verf[NFS_DIR_VERIFIER_SIZE];
 	unsigned long	dir_verifier;
@@ -167,24 +168,47 @@ struct nfs_readdir_descriptor {
 	unsigned long	gencount;
 	unsigned long	attr_gencount;
 	unsigned int	cache_entry_index;
-	signed char duped;
+	unsigned int	buffer_fills;
+	unsigned int	dtsize;
+	bool clear_cache;
 	bool plus;
 	bool eob;
 	bool eof;
 };
 
-static void nfs_readdir_array_init(struct nfs_cache_array *array)
+static void nfs_set_dtsize(struct nfs_readdir_descriptor *desc, unsigned int sz)
+{
+	struct nfs_server *server = NFS_SERVER(file_inode(desc->file));
+	unsigned int maxsize = server->dtsize;
+
+	if (sz > maxsize)
+		sz = maxsize;
+	if (sz < NFS_MIN_FILE_IO_SIZE)
+		sz = NFS_MIN_FILE_IO_SIZE;
+	desc->dtsize = sz;
+}
+
+static void nfs_shrink_dtsize(struct nfs_readdir_descriptor *desc)
 {
-	memset(array, 0, sizeof(struct nfs_cache_array));
+	nfs_set_dtsize(desc, desc->dtsize >> 1);
 }
 
-static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie)
+static void nfs_grow_dtsize(struct nfs_readdir_descriptor *desc)
+{
+	nfs_set_dtsize(desc, desc->dtsize << 1);
+}
+
+static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie,
+					u64 change_attr)
 {
 	struct nfs_cache_array *array;
 
 	array = kmap_atomic(page);
-	nfs_readdir_array_init(array);
+	array->change_attr = change_attr;
 	array->last_cookie = last_cookie;
+	array->size = 0;
+	array->page_full = 0;
+	array->page_is_eof = 0;
 	array->cookies_are_ordered = 1;
 	kunmap_atomic(array);
 }
@@ -192,25 +216,31 @@ static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie)
 /*
  * we are freeing strings created by nfs_add_to_readdir_array()
  */
-static
-void nfs_readdir_clear_array(struct page *page)
+static void nfs_readdir_clear_array(struct page *page)
 {
 	struct nfs_cache_array *array;
-	int i;
+	unsigned int i;
 
 	array = kmap_atomic(page);
 	for (i = 0; i < array->size; i++)
 		kfree(array->array[i].name);
-	nfs_readdir_array_init(array);
+	array->size = 0;
 	kunmap_atomic(array);
 }
 
+static void nfs_readdir_page_reinit_array(struct page *page, u64 last_cookie,
+					  u64 change_attr)
+{
+	nfs_readdir_clear_array(page);
+	nfs_readdir_page_init_array(page, last_cookie, change_attr);
+}
+
 static struct page *
 nfs_readdir_page_array_alloc(u64 last_cookie, gfp_t gfp_flags)
 {
 	struct page *page = alloc_page(gfp_flags);
 	if (page)
-		nfs_readdir_page_init_array(page, last_cookie);
+		nfs_readdir_page_init_array(page, last_cookie, 0);
 	return page;
 }
 
@@ -222,6 +252,11 @@ static void nfs_readdir_page_array_free(struct page *page)
 	}
 }
 
+static u64 nfs_readdir_array_index_cookie(struct nfs_cache_array *array)
+{
+	return array->size == 0 ? array->last_cookie : array->array[0].cookie;
+}
+
 static void nfs_readdir_array_set_eof(struct nfs_cache_array *array)
 {
 	array->page_is_eof = 1;
@@ -251,36 +286,40 @@ static const char *nfs_readdir_copy_name(const char *name, unsigned int len)
 	return ret;
 }
 
+static size_t nfs_readdir_array_maxentries(void)
+{
+	return (PAGE_SIZE - sizeof(struct nfs_cache_array)) /
+	       sizeof(struct nfs_cache_array_entry);
+}
+
 /*
  * Check that the next array entry lies entirely within the page bounds
  */
 static int nfs_readdir_array_can_expand(struct nfs_cache_array *array)
 {
-	struct nfs_cache_array_entry *cache_entry;
-
 	if (array->page_full)
 		return -ENOSPC;
-	cache_entry = &array->array[array->size + 1];
-	if ((char *)cache_entry - (char *)array > PAGE_SIZE) {
+	if (array->size == nfs_readdir_array_maxentries()) {
 		array->page_full = 1;
 		return -ENOSPC;
 	}
 	return 0;
 }
 
-static
-int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
+static int nfs_readdir_page_array_append(struct page *page,
+					 const struct nfs_entry *entry,
+					 u64 *cookie)
 {
 	struct nfs_cache_array *array;
 	struct nfs_cache_array_entry *cache_entry;
 	const char *name;
-	int ret;
+	int ret = -ENOMEM;
 
 	name = nfs_readdir_copy_name(entry->name, entry->len);
-	if (!name)
-		return -ENOMEM;
 
 	array = kmap_atomic(page);
+	if (!name)
+		goto out;
 	ret = nfs_readdir_array_can_expand(array);
 	if (ret) {
 		kfree(name);
@@ -288,7 +327,7 @@ int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
 	}
 
 	cache_entry = &array->array[array->size];
-	cache_entry->cookie = entry->prev_cookie;
+	cache_entry->cookie = array->last_cookie;
 	cache_entry->ino = entry->ino;
 	cache_entry->d_type = entry->d_type;
 	cache_entry->name_len = entry->len;
@@ -300,23 +339,72 @@ int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
 	if (entry->eof != 0)
 		nfs_readdir_array_set_eof(array);
 out:
+	*cookie = array->last_cookie;
+	kunmap_atomic(array);
+	return ret;
+}
+
+#define NFS_READDIR_COOKIE_MASK (U32_MAX >> 14)
+/*
+ * Hash algorithm allowing content addressible access to sequences
+ * of directory cookies. Content is addressed by the value of the
+ * cookie index of the first readdir entry in a page.
+ *
+ * We select only the first 18 bits to avoid issues with excessive
+ * memory use for the page cache XArray. 18 bits should allow the caching
+ * of 262144 pages of sequences of readdir entries. Since each page holds
+ * 127 readdir entries for a typical 64-bit system, that works out to a
+ * cache of ~ 33 million entries per directory.
+ */
+static pgoff_t nfs_readdir_page_cookie_hash(u64 cookie)
+{
+	if (cookie == 0)
+		return 0;
+	return hash_64(cookie, 18);
+}
+
+static bool nfs_readdir_page_validate(struct page *page, u64 last_cookie,
+				      u64 change_attr)
+{
+	struct nfs_cache_array *array = kmap_atomic(page);
+	int ret = true;
+
+	if (array->change_attr != change_attr)
+		ret = false;
+	if (nfs_readdir_array_index_cookie(array) != last_cookie)
+		ret = false;
 	kunmap_atomic(array);
 	return ret;
 }
 
+static void nfs_readdir_page_unlock_and_put(struct page *page)
+{
+	unlock_page(page);
+	put_page(page);
+}
+
+static void nfs_readdir_page_init_and_validate(struct page *page, u64 cookie,
+					       u64 change_attr)
+{
+	if (PageUptodate(page)) {
+		if (nfs_readdir_page_validate(page, cookie, change_attr))
+			return;
+		nfs_readdir_clear_array(page);
+	}
+	nfs_readdir_page_init_array(page, cookie, change_attr);
+	SetPageUptodate(page);
+}
+
 static struct page *nfs_readdir_page_get_locked(struct address_space *mapping,
-						pgoff_t index, u64 last_cookie)
+						u64 cookie, u64 change_attr)
 {
+	pgoff_t index = nfs_readdir_page_cookie_hash(cookie);
 	struct page *page;
 
 	page = grab_cache_page(mapping, index);
-	if (page && !PageUptodate(page)) {
-		nfs_readdir_page_init_array(page, last_cookie);
-		if (invalidate_inode_pages2_range(mapping, index + 1, -1) < 0)
-			nfs_zap_mapping(mapping->host, mapping);
-		SetPageUptodate(page);
-	}
-
+	if (!page)
+		return NULL;
+	nfs_readdir_page_init_and_validate(page, cookie, change_attr);
 	return page;
 }
 
@@ -351,24 +439,19 @@ static void nfs_readdir_page_set_eof(struct page *page)
 	kunmap_atomic(array);
 }
 
-static void nfs_readdir_page_unlock_and_put(struct page *page)
-{
-	unlock_page(page);
-	put_page(page);
-}
-
 static struct page *nfs_readdir_page_get_next(struct address_space *mapping,
-					      pgoff_t index, u64 cookie)
+					      u64 cookie, u64 change_attr)
 {
+	pgoff_t index = nfs_readdir_page_cookie_hash(cookie);
 	struct page *page;
 
-	page = nfs_readdir_page_get_locked(mapping, index, cookie);
-	if (page) {
-		if (nfs_readdir_page_last_cookie(page) == cookie)
-			return page;
-		nfs_readdir_page_unlock_and_put(page);
-	}
-	return NULL;
+	page = grab_cache_page_nowait(mapping, index);
+	if (!page)
+		return NULL;
+	nfs_readdir_page_init_and_validate(page, cookie, change_attr);
+	if (nfs_readdir_page_last_cookie(page) != cookie)
+		nfs_readdir_page_reinit_array(page, cookie, change_attr);
+	return page;
 }
 
 static inline
@@ -390,6 +473,25 @@ bool nfs_readdir_use_cookie(const struct file *filp)
 	return true;
 }
 
+static void nfs_readdir_seek_next_array(struct nfs_cache_array *array,
+					struct nfs_readdir_descriptor *desc)
+{
+	if (array->page_full) {
+		desc->last_cookie = array->last_cookie;
+		desc->current_index += array->size;
+		desc->cache_entry_index = 0;
+		desc->page_index++;
+	} else
+		desc->last_cookie = nfs_readdir_array_index_cookie(array);
+}
+
+static void nfs_readdir_rewind_search(struct nfs_readdir_descriptor *desc)
+{
+	desc->current_index = 0;
+	desc->last_cookie = 0;
+	desc->page_index = 0;
+}
+
 static int nfs_readdir_search_for_pos(struct nfs_cache_array *array,
 				      struct nfs_readdir_descriptor *desc)
 {
@@ -401,6 +503,7 @@ static int nfs_readdir_search_for_pos(struct nfs_cache_array *array,
 	if (diff >= array->size) {
 		if (array->page_is_eof)
 			goto out_eof;
+		nfs_readdir_seek_next_array(array, desc);
 		return -EAGAIN;
 	}
 
@@ -413,16 +516,6 @@ out_eof:
 	return -EBADCOOKIE;
 }
 
-static bool
-nfs_readdir_inode_mapping_valid(struct nfs_inode *nfsi)
-{
-	if (nfsi->cache_validity & (NFS_INO_INVALID_CHANGE |
-				    NFS_INO_INVALID_DATA))
-		return false;
-	smp_rmb();
-	return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags);
-}
-
 static bool nfs_readdir_array_cookie_in_range(struct nfs_cache_array *array,
 					      u64 cookie)
 {
@@ -439,8 +532,7 @@ static bool nfs_readdir_array_cookie_in_range(struct nfs_cache_array *array,
 static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array,
 					 struct nfs_readdir_descriptor *desc)
 {
-	int i;
-	loff_t new_pos;
+	unsigned int i;
 	int status = -EAGAIN;
 
 	if (!nfs_readdir_array_cookie_in_range(array, desc->dir_cookie))
@@ -448,33 +540,10 @@ static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array,
 
 	for (i = 0; i < array->size; i++) {
 		if (array->array[i].cookie == desc->dir_cookie) {
-			struct nfs_inode *nfsi = NFS_I(file_inode(desc->file));
-
-			new_pos = desc->current_index + i;
-			if (desc->attr_gencount != nfsi->attr_gencount ||
-			    !nfs_readdir_inode_mapping_valid(nfsi)) {
-				desc->duped = 0;
-				desc->attr_gencount = nfsi->attr_gencount;
-			} else if (new_pos < desc->prev_index) {
-				if (desc->duped > 0
-				    && desc->dup_cookie == desc->dir_cookie) {
-					if (printk_ratelimit()) {
-						pr_notice("NFS: directory %pD2 contains a readdir loop."
-								"Please contact your server vendor.  "
-								"The file: %s has duplicate cookie %llu\n",
-								desc->file, array->array[i].name, desc->dir_cookie);
-					}
-					status = -ELOOP;
-					goto out;
-				}
-				desc->dup_cookie = desc->dir_cookie;
-				desc->duped = -1;
-			}
 			if (nfs_readdir_use_cookie(desc->file))
 				desc->ctx->pos = desc->dir_cookie;
 			else
-				desc->ctx->pos = new_pos;
-			desc->prev_index = new_pos;
+				desc->ctx->pos = desc->current_index + i;
 			desc->cache_entry_index = i;
 			return 0;
 		}
@@ -484,8 +553,8 @@ check_eof:
 		status = -EBADCOOKIE;
 		if (desc->dir_cookie == array->last_cookie)
 			desc->eof = true;
-	}
-out:
+	} else
+		nfs_readdir_seek_next_array(array, desc);
 	return status;
 }
 
@@ -501,11 +570,6 @@ static int nfs_readdir_search_array(struct nfs_readdir_descriptor *desc)
 	else
 		status = nfs_readdir_search_for_cookie(array, desc);
 
-	if (status == -EAGAIN) {
-		desc->last_cookie = array->last_cookie;
-		desc->current_index += array->size;
-		desc->page_index++;
-	}
 	kunmap_atomic(array);
 	return status;
 }
@@ -541,7 +605,6 @@ static int nfs_readdir_xdr_filler(struct nfs_readdir_descriptor *desc,
 		/* We requested READDIRPLUS, but the server doesn't grok it */
 		if (error == -ENOTSUPP && desc->plus) {
 			NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
-			clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
 			desc->plus = arg.plus = false;
 			goto again;
 		}
@@ -591,51 +654,68 @@ int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry)
 	return 1;
 }
 
-static
-bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx)
+#define NFS_READDIR_CACHE_USAGE_THRESHOLD (8UL)
+
+static bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx,
+				unsigned int cache_hits,
+				unsigned int cache_misses)
 {
 	if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS))
 		return false;
-	if (test_and_clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags))
-		return true;
-	if (ctx->pos == 0)
+	if (ctx->pos == 0 ||
+	    cache_hits + cache_misses > NFS_READDIR_CACHE_USAGE_THRESHOLD)
 		return true;
 	return false;
 }
 
 /*
- * This function is called by the lookup and getattr code to request the
+ * This function is called by the getattr code to request the
  * use of readdirplus to accelerate any future lookups in the same
  * directory.
  */
-void nfs_advise_use_readdirplus(struct inode *dir)
+void nfs_readdir_record_entry_cache_hit(struct inode *dir)
 {
 	struct nfs_inode *nfsi = NFS_I(dir);
+	struct nfs_open_dir_context *ctx;
 
 	if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
-	    !list_empty(&nfsi->open_files))
-		set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
+	    S_ISDIR(dir->i_mode)) {
+		rcu_read_lock();
+		list_for_each_entry_rcu (ctx, &nfsi->open_files, list)
+			atomic_inc(&ctx->cache_hits);
+		rcu_read_unlock();
+	}
 }
 
 /*
  * This function is mainly for use by nfs_getattr().
  *
  * If this is an 'ls -l', we want to force use of readdirplus.
- * Do this by checking if there is an active file descriptor
- * and calling nfs_advise_use_readdirplus, then forcing a
- * cache flush.
  */
-void nfs_force_use_readdirplus(struct inode *dir)
+void nfs_readdir_record_entry_cache_miss(struct inode *dir)
 {
 	struct nfs_inode *nfsi = NFS_I(dir);
+	struct nfs_open_dir_context *ctx;
 
 	if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
-	    !list_empty(&nfsi->open_files)) {
-		set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
-		set_bit(NFS_INO_FORCE_READDIR, &nfsi->flags);
+	    S_ISDIR(dir->i_mode)) {
+		rcu_read_lock();
+		list_for_each_entry_rcu (ctx, &nfsi->open_files, list)
+			atomic_inc(&ctx->cache_misses);
+		rcu_read_unlock();
 	}
 }
 
+static void nfs_lookup_advise_force_readdirplus(struct inode *dir,
+						unsigned int flags)
+{
+	if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))
+		return;
+	if (flags & (LOOKUP_EXCL | LOOKUP_PARENT | LOOKUP_REVAL))
+		return;
+	nfs_readdir_record_entry_cache_miss(dir);
+}
+
 static
 void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry,
 		unsigned long dir_verifier)
@@ -686,8 +766,12 @@ again:
 			status = nfs_refresh_inode(d_inode(dentry), entry->fattr);
 			if (!status)
 				nfs_setsecurity(d_inode(dentry), entry->fattr);
+			trace_nfs_readdir_lookup_revalidate(d_inode(parent),
+							    dentry, 0, status);
 			goto out;
 		} else {
+			trace_nfs_readdir_lookup_revalidate_failed(
+				d_inode(parent), dentry, 0);
 			d_invalidate(dentry);
 			dput(dentry);
 			dentry = NULL;
@@ -709,22 +793,38 @@ again:
 		dentry = alias;
 	}
 	nfs_set_verifier(dentry, dir_verifier);
+	trace_nfs_readdir_lookup(d_inode(parent), dentry, 0);
 out:
 	dput(dentry);
 }
 
+static int nfs_readdir_entry_decode(struct nfs_readdir_descriptor *desc,
+				    struct nfs_entry *entry,
+				    struct xdr_stream *stream)
+{
+	int ret;
+
+	if (entry->fattr->label)
+		entry->fattr->label->len = NFS4_MAXLABELLEN;
+	ret = xdr_decode(desc, entry, stream);
+	if (ret || !desc->plus)
+		return ret;
+	nfs_prime_dcache(file_dentry(desc->file), entry, desc->dir_verifier);
+	return 0;
+}
+
 /* Perform conversion from xdr to cache array */
 static int nfs_readdir_page_filler(struct nfs_readdir_descriptor *desc,
 				   struct nfs_entry *entry,
-				   struct page **xdr_pages,
-				   unsigned int buflen,
-				   struct page **arrays,
-				   size_t narrays)
+				   struct page **xdr_pages, unsigned int buflen,
+				   struct page **arrays, size_t narrays,
+				   u64 change_attr)
 {
 	struct address_space *mapping = desc->file->f_mapping;
 	struct xdr_stream stream;
 	struct xdr_buf buf;
 	struct page *scratch, *new, *page = *arrays;
+	u64 cookie;
 	int status;
 
 	scratch = alloc_page(GFP_KERNEL);
@@ -735,54 +835,50 @@ static int nfs_readdir_page_filler(struct nfs_readdir_descriptor *desc,
 	xdr_set_scratch_page(&stream, scratch);
 
 	do {
-		if (entry->fattr->label)
-			entry->fattr->label->len = NFS4_MAXLABELLEN;
-
-		status = xdr_decode(desc, entry, &stream);
+		status = nfs_readdir_entry_decode(desc, entry, &stream);
 		if (status != 0)
 			break;
 
-		if (desc->plus)
-			nfs_prime_dcache(file_dentry(desc->file), entry,
-					desc->dir_verifier);
-
-		status = nfs_readdir_add_to_array(entry, page);
+		status = nfs_readdir_page_array_append(page, entry, &cookie);
 		if (status != -ENOSPC)
 			continue;
 
 		if (page->mapping != mapping) {
 			if (!--narrays)
 				break;
-			new = nfs_readdir_page_array_alloc(entry->prev_cookie,
-							   GFP_KERNEL);
+			new = nfs_readdir_page_array_alloc(cookie, GFP_KERNEL);
 			if (!new)
 				break;
 			arrays++;
 			*arrays = page = new;
 		} else {
-			new = nfs_readdir_page_get_next(mapping,
-							page->index + 1,
-							entry->prev_cookie);
+			new = nfs_readdir_page_get_next(mapping, cookie,
+							change_attr);
 			if (!new)
 				break;
 			if (page != *arrays)
 				nfs_readdir_page_unlock_and_put(page);
 			page = new;
 		}
-		status = nfs_readdir_add_to_array(entry, page);
+		desc->page_index_max++;
+		status = nfs_readdir_page_array_append(page, entry, &cookie);
 	} while (!status && !entry->eof);
 
 	switch (status) {
 	case -EBADCOOKIE:
-		if (entry->eof) {
-			nfs_readdir_page_set_eof(page);
-			status = 0;
-		}
-		break;
-	case -ENOSPC:
+		if (!entry->eof)
+			break;
+		nfs_readdir_page_set_eof(page);
+		fallthrough;
 	case -EAGAIN:
 		status = 0;
 		break;
+	case -ENOSPC:
+		status = 0;
+		if (!desc->plus)
+			break;
+		while (!nfs_readdir_entry_decode(desc, entry, &stream))
+			;
 	}
 
 	if (page != *arrays)
@@ -828,12 +924,14 @@ static int nfs_readdir_xdr_to_array(struct nfs_readdir_descriptor *desc,
 				    __be32 *verf_arg, __be32 *verf_res,
 				    struct page **arrays, size_t narrays)
 {
+	u64 change_attr;
 	struct page **pages;
 	struct page *page = *arrays;
 	struct nfs_entry *entry;
 	size_t array_size;
 	struct inode *inode = file_inode(desc->file);
-	size_t dtsize = NFS_SERVER(inode)->dtsize;
+	unsigned int dtsize = desc->dtsize;
+	unsigned int pglen;
 	int status = -ENOMEM;
 
 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
@@ -851,27 +949,21 @@ static int nfs_readdir_xdr_to_array(struct nfs_readdir_descriptor *desc,
 	if (!pages)
 		goto out;
 
-	do {
-		unsigned int pglen;
-		status = nfs_readdir_xdr_filler(desc, verf_arg, entry->cookie,
-						pages, dtsize,
-						verf_res);
-		if (status < 0)
-			break;
-
-		pglen = status;
-		if (pglen == 0) {
-			nfs_readdir_page_set_eof(page);
-			break;
-		}
-
-		verf_arg = verf_res;
+	change_attr = inode_peek_iversion_raw(inode);
+	status = nfs_readdir_xdr_filler(desc, verf_arg, entry->cookie, pages,
+					dtsize, verf_res);
+	if (status < 0)
+		goto free_pages;
 
+	pglen = status;
+	if (pglen != 0)
 		status = nfs_readdir_page_filler(desc, entry, pages, pglen,
-						 arrays, narrays);
-	} while (!status && nfs_readdir_page_needs_filling(page) &&
-		page_mapping(page));
+						 arrays, narrays, change_attr);
+	else
+		nfs_readdir_page_set_eof(page);
+	desc->buffer_fills++;
 
+free_pages:
 	nfs_readdir_free_pages(pages, array_size);
 out:
 	nfs_free_fattr(entry->fattr);
@@ -896,9 +988,17 @@ nfs_readdir_page_unlock_and_put_cached(struct nfs_readdir_descriptor *desc)
 static struct page *
 nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc)
 {
-	return nfs_readdir_page_get_locked(desc->file->f_mapping,
-					   desc->page_index,
-					   desc->last_cookie);
+	struct address_space *mapping = desc->file->f_mapping;
+	u64 change_attr = inode_peek_iversion_raw(mapping->host);
+	u64 cookie = desc->last_cookie;
+	struct page *page;
+
+	page = nfs_readdir_page_get_locked(mapping, cookie, change_attr);
+	if (!page)
+		return NULL;
+	if (desc->clear_cache && !nfs_readdir_page_needs_filling(page))
+		nfs_readdir_page_reinit_array(page, cookie, change_attr);
+	return page;
 }
 
 /*
@@ -916,13 +1016,23 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
 	if (!desc->page)
 		return -ENOMEM;
 	if (nfs_readdir_page_needs_filling(desc->page)) {
+		/* Grow the dtsize if we had to go back for more pages */
+		if (desc->page_index == desc->page_index_max)
+			nfs_grow_dtsize(desc);
+		desc->page_index_max = desc->page_index;
+		trace_nfs_readdir_cache_fill(desc->file, nfsi->cookieverf,
+					     desc->last_cookie,
+					     desc->page->index, desc->dtsize);
 		res = nfs_readdir_xdr_to_array(desc, nfsi->cookieverf, verf,
 					       &desc->page, 1);
 		if (res < 0) {
 			nfs_readdir_page_unlock_and_put_cached(desc);
+			trace_nfs_readdir_cache_fill_done(inode, res);
 			if (res == -EBADCOOKIE || res == -ENOTSYNC) {
 				invalidate_inode_pages2(desc->file->f_mapping);
-				desc->page_index = 0;
+				nfs_readdir_rewind_search(desc);
+				trace_nfs_readdir_invalidate_cache_range(
+					inode, 0, MAX_LFS_FILESIZE);
 				return -EAGAIN;
 			}
 			return res;
@@ -930,9 +1040,16 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
 		/*
 		 * Set the cookie verifier if the page cache was empty
 		 */
-		if (desc->page_index == 0)
+		if (desc->last_cookie == 0 &&
+		    memcmp(nfsi->cookieverf, verf, sizeof(nfsi->cookieverf))) {
 			memcpy(nfsi->cookieverf, verf,
 			       sizeof(nfsi->cookieverf));
+			invalidate_inode_pages2_range(desc->file->f_mapping, 1,
+						      -1);
+			trace_nfs_readdir_invalidate_cache_range(
+				inode, 1, MAX_LFS_FILESIZE);
+		}
+		desc->clear_cache = false;
 	}
 	res = nfs_readdir_search_array(desc);
 	if (res == 0)
@@ -941,34 +1058,12 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
 	return res;
 }
 
-static bool nfs_readdir_dont_search_cache(struct nfs_readdir_descriptor *desc)
-{
-	struct address_space *mapping = desc->file->f_mapping;
-	struct inode *dir = file_inode(desc->file);
-	unsigned int dtsize = NFS_SERVER(dir)->dtsize;
-	loff_t size = i_size_read(dir);
-
-	/*
-	 * Default to uncached readdir if the page cache is empty, and
-	 * we're looking for a non-zero cookie in a large directory.
-	 */
-	return desc->dir_cookie != 0 && mapping->nrpages == 0 && size > dtsize;
-}
-
 /* Search for desc->dir_cookie from the beginning of the page cache */
 static int readdir_search_pagecache(struct nfs_readdir_descriptor *desc)
 {
 	int res;
 
-	if (nfs_readdir_dont_search_cache(desc))
-		return -EBADCOOKIE;
-
 	do {
-		if (desc->page_index == 0) {
-			desc->current_index = 0;
-			desc->prev_index = 0;
-			desc->last_cookie = 0;
-		}
 		res = find_and_lock_cache_page(desc);
 	} while (res == -EAGAIN);
 	return res;
@@ -982,7 +1077,7 @@ static void nfs_do_filldir(struct nfs_readdir_descriptor *desc,
 {
 	struct file	*file = desc->file;
 	struct nfs_cache_array *array;
-	unsigned int i = 0;
+	unsigned int i;
 
 	array = kmap(desc->page);
 	for (i = desc->cache_entry_index; i < array->size; i++) {
@@ -995,16 +1090,17 @@ static void nfs_do_filldir(struct nfs_readdir_descriptor *desc,
 			break;
 		}
 		memcpy(desc->verf, verf, sizeof(desc->verf));
-		if (i < (array->size-1))
-			desc->dir_cookie = array->array[i+1].cookie;
-		else
+		if (i == array->size - 1) {
 			desc->dir_cookie = array->last_cookie;
+			nfs_readdir_seek_next_array(array, desc);
+		} else {
+			desc->dir_cookie = array->array[i + 1].cookie;
+			desc->last_cookie = array->array[0].cookie;
+		}
 		if (nfs_readdir_use_cookie(file))
 			desc->ctx->pos = desc->dir_cookie;
 		else
 			desc->ctx->pos++;
-		if (desc->duped != 0)
-			desc->duped = 1;
 	}
 	if (array->page_is_eof)
 		desc->eof = !desc->eob;
@@ -1046,9 +1142,16 @@ static int uncached_readdir(struct nfs_readdir_descriptor *desc)
 	desc->page_index = 0;
 	desc->cache_entry_index = 0;
 	desc->last_cookie = desc->dir_cookie;
-	desc->duped = 0;
+	desc->page_index_max = 0;
+
+	trace_nfs_readdir_uncached(desc->file, desc->verf, desc->last_cookie,
+				   -1, desc->dtsize);
 
 	status = nfs_readdir_xdr_to_array(desc, desc->verf, verf, arrays, sz);
+	if (status < 0) {
+		trace_nfs_readdir_uncached_done(file_inode(desc->file), status);
+		goto out_free;
+	}
 
 	for (i = 0; !desc->eob && i < sz && arrays[i]; i++) {
 		desc->page = arrays[i];
@@ -1056,15 +1159,44 @@ static int uncached_readdir(struct nfs_readdir_descriptor *desc)
 	}
 	desc->page = NULL;
 
-
+	/*
+	 * Grow the dtsize if we have to go back for more pages,
+	 * or shrink it if we're reading too many.
+	 */
+	if (!desc->eof) {
+		if (!desc->eob)
+			nfs_grow_dtsize(desc);
+		else if (desc->buffer_fills == 1 &&
+			 i < (desc->page_index_max >> 1))
+			nfs_shrink_dtsize(desc);
+	}
+out_free:
 	for (i = 0; i < sz && arrays[i]; i++)
 		nfs_readdir_page_array_free(arrays[i]);
 out:
+	if (!nfs_readdir_use_cookie(desc->file))
+		nfs_readdir_rewind_search(desc);
+	desc->page_index_max = -1;
 	kfree(arrays);
 	dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status);
 	return status;
 }
 
+#define NFS_READDIR_CACHE_MISS_THRESHOLD (16UL)
+
+static bool nfs_readdir_handle_cache_misses(struct inode *inode,
+					    struct nfs_readdir_descriptor *desc,
+					    unsigned int cache_misses,
+					    bool force_clear)
+{
+	if (desc->ctx->pos == 0 || !desc->plus)
+		return false;
+	if (cache_misses <= NFS_READDIR_CACHE_MISS_THRESHOLD && !force_clear)
+		return false;
+	trace_nfs_readdir_force_readdirplus(inode);
+	return true;
+}
+
 /* The file offset position represents the dirent entry number.  A
    last cookie cache takes care of the common case of reading the
    whole directory.
@@ -1076,7 +1208,8 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
 	struct nfs_inode *nfsi = NFS_I(inode);
 	struct nfs_open_dir_context *dir_ctx = file->private_data;
 	struct nfs_readdir_descriptor *desc;
-	pgoff_t page_index;
+	unsigned int cache_hits, cache_misses;
+	bool force_clear;
 	int res;
 
 	dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n",
@@ -1089,11 +1222,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
 	 * to either find the entry with the appropriate number or
 	 * revalidate the cookie.
 	 */
-	if (ctx->pos == 0 || nfs_attribute_cache_expired(inode)) {
-		res = nfs_revalidate_mapping(inode, file->f_mapping);
-		if (res < 0)
-			goto out;
-	}
+	nfs_revalidate_mapping(inode, file->f_mapping);
 
 	res = -ENOMEM;
 	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
@@ -1101,16 +1230,19 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
 		goto out;
 	desc->file = file;
 	desc->ctx = ctx;
-	desc->plus = nfs_use_readdirplus(inode, ctx);
+	desc->page_index_max = -1;
 
 	spin_lock(&file->f_lock);
 	desc->dir_cookie = dir_ctx->dir_cookie;
-	desc->dup_cookie = dir_ctx->dup_cookie;
-	desc->duped = dir_ctx->duped;
-	page_index = dir_ctx->page_index;
+	desc->page_index = dir_ctx->page_index;
+	desc->last_cookie = dir_ctx->last_cookie;
 	desc->attr_gencount = dir_ctx->attr_gencount;
 	desc->eof = dir_ctx->eof;
+	nfs_set_dtsize(desc, dir_ctx->dtsize);
 	memcpy(desc->verf, dir_ctx->verf, sizeof(desc->verf));
+	cache_hits = atomic_xchg(&dir_ctx->cache_hits, 0);
+	cache_misses = atomic_xchg(&dir_ctx->cache_misses, 0);
+	force_clear = dir_ctx->force_clear;
 	spin_unlock(&file->f_lock);
 
 	if (desc->eof) {
@@ -1118,9 +1250,10 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
 		goto out_free;
 	}
 
-	if (test_and_clear_bit(NFS_INO_FORCE_READDIR, &nfsi->flags) &&
-	    list_is_singular(&nfsi->open_files))
-		invalidate_mapping_pages(inode->i_mapping, page_index + 1, -1);
+	desc->plus = nfs_use_readdirplus(inode, ctx, cache_hits, cache_misses);
+	force_clear = nfs_readdir_handle_cache_misses(inode, desc, cache_misses,
+						      force_clear);
+	desc->clear_cache = force_clear;
 
 	do {
 		res = readdir_search_pagecache(desc);
@@ -1139,9 +1272,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
 			break;
 		}
 		if (res == -ETOOSMALL && desc->plus) {
-			clear_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
 			nfs_zap_caches(inode);
-			desc->page_index = 0;
 			desc->plus = false;
 			desc->eof = false;
 			continue;
@@ -1151,15 +1282,18 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
 
 		nfs_do_filldir(desc, nfsi->cookieverf);
 		nfs_readdir_page_unlock_and_put_cached(desc);
+		if (desc->page_index == desc->page_index_max)
+			desc->clear_cache = force_clear;
 	} while (!desc->eob && !desc->eof);
 
 	spin_lock(&file->f_lock);
 	dir_ctx->dir_cookie = desc->dir_cookie;
-	dir_ctx->dup_cookie = desc->dup_cookie;
-	dir_ctx->duped = desc->duped;
+	dir_ctx->last_cookie = desc->last_cookie;
 	dir_ctx->attr_gencount = desc->attr_gencount;
 	dir_ctx->page_index = desc->page_index;
+	dir_ctx->force_clear = force_clear;
 	dir_ctx->eof = desc->eof;
+	dir_ctx->dtsize = desc->dtsize;
 	memcpy(dir_ctx->verf, desc->verf, sizeof(dir_ctx->verf));
 	spin_unlock(&file->f_lock);
 out_free:
@@ -1197,13 +1331,14 @@ static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
 	}
 	if (offset != filp->f_pos) {
 		filp->f_pos = offset;
-		if (nfs_readdir_use_cookie(filp))
-			dir_ctx->dir_cookie = offset;
-		else
+		dir_ctx->page_index = 0;
+		if (!nfs_readdir_use_cookie(filp)) {
 			dir_ctx->dir_cookie = 0;
-		if (offset == 0)
-			memset(dir_ctx->verf, 0, sizeof(dir_ctx->verf));
-		dir_ctx->duped = 0;
+			dir_ctx->last_cookie = 0;
+		} else {
+			dir_ctx->dir_cookie = offset;
+			dir_ctx->last_cookie = offset;
+		}
 		dir_ctx->eof = false;
 	}
 	spin_unlock(&filp->f_lock);
@@ -1419,7 +1554,12 @@ int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags)
 	if (flags & LOOKUP_REVAL)
 		goto out_force;
 out:
-	return (inode->i_nlink == 0) ? -ESTALE : 0;
+	if (inode->i_nlink > 0 ||
+	    (inode->i_nlink == 0 &&
+	     test_bit(NFS_INO_PRESERVE_UNLINKED, &NFS_I(inode)->flags)))
+		return 0;
+	else
+		return -ESTALE;
 out_force:
 	if (flags & LOOKUP_RCU)
 		return -ECHILD;
@@ -1469,9 +1609,7 @@ nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry,
 {
 	switch (error) {
 	case 1:
-		dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is valid\n",
-			__func__, dentry);
-		return 1;
+		break;
 	case 0:
 		/*
 		 * We can't d_drop the root of a disconnected tree:
@@ -1480,13 +1618,10 @@ nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry,
 		 * inodes on unmount and further oopses.
 		 */
 		if (inode && IS_ROOT(dentry))
-			return 1;
-		dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n",
-				__func__, dentry);
-		return 0;
+			error = 1;
+		break;
 	}
-	dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) lookup returned error %d\n",
-				__func__, dentry, error);
+	trace_nfs_lookup_revalidate_exit(dir, dentry, 0, error);
 	return error;
 }
 
@@ -1511,15 +1646,17 @@ nfs_lookup_revalidate_delegated(struct inode *dir, struct dentry *dentry,
 	return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
 }
 
-static int
-nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
-			     struct inode *inode)
+static int nfs_lookup_revalidate_dentry(struct inode *dir,
+					struct dentry *dentry,
+					struct inode *inode, unsigned int flags)
 {
 	struct nfs_fh *fhandle;
 	struct nfs_fattr *fattr;
 	unsigned long dir_verifier;
 	int ret;
 
+	trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
+
 	ret = -ENOMEM;
 	fhandle = nfs_alloc_fhandle();
 	fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode));
@@ -1540,6 +1677,10 @@ nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
 		}
 		goto out;
 	}
+
+	/* Request help from readdirplus */
+	nfs_lookup_advise_force_readdirplus(dir, flags);
+
 	ret = 0;
 	if (nfs_compare_fh(NFS_FH(inode), fhandle))
 		goto out;
@@ -1549,8 +1690,6 @@ nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
 	nfs_setsecurity(inode, fattr);
 	nfs_set_verifier(dentry, dir_verifier);
 
-	/* set a readdirplus hint that we had a cache miss */
-	nfs_force_use_readdirplus(dir);
 	ret = 1;
 out:
 	nfs_free_fattr(fattr);
@@ -1607,7 +1746,6 @@ nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
 				nfs_mark_dir_for_revalidate(dir);
 			goto out_bad;
 		}
-		nfs_advise_use_readdirplus(dir);
 		goto out_valid;
 	}
 
@@ -1617,10 +1755,7 @@ nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
 	if (NFS_STALE(inode))
 		goto out_bad;
 
-	trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
-	error = nfs_lookup_revalidate_dentry(dir, dentry, inode);
-	trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error);
-	return error;
+	return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags);
 out_valid:
 	return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
 out_bad:
@@ -1814,7 +1949,7 @@ struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned in
 		goto out;
 
 	/* Notify readdir to use READDIRPLUS */
-	nfs_force_use_readdirplus(dir);
+	nfs_lookup_advise_force_readdirplus(dir, flags);
 
 no_entry:
 	res = d_splice_alias(inode, dentry);
@@ -1853,16 +1988,6 @@ const struct dentry_operations nfs4_dentry_operations = {
 };
 EXPORT_SYMBOL_GPL(nfs4_dentry_operations);
 
-static fmode_t flags_to_mode(int flags)
-{
-	fmode_t res = (__force fmode_t)flags & FMODE_EXEC;
-	if ((flags & O_ACCMODE) != O_WRONLY)
-		res |= FMODE_READ;
-	if ((flags & O_ACCMODE) != O_RDONLY)
-		res |= FMODE_WRITE;
-	return res;
-}
-
 static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp)
 {
 	return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp);
@@ -2077,7 +2202,7 @@ nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
 reval_dentry:
 	if (flags & LOOKUP_RCU)
 		return -ECHILD;
-	return nfs_lookup_revalidate_dentry(dir, dentry, inode);
+	return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags);
 
 full_reval:
 	return nfs_do_lookup_revalidate(dir, dentry, flags);
@@ -2330,7 +2455,8 @@ int nfs_unlink(struct inode *dir, struct dentry *dentry)
 
 	trace_nfs_unlink_enter(dir, dentry);
 	spin_lock(&dentry->d_lock);
-	if (d_count(dentry) > 1) {
+	if (d_count(dentry) > 1 && !test_bit(NFS_INO_PRESERVE_UNLINKED,
+					     &NFS_I(d_inode(dentry))->flags)) {
 		spin_unlock(&dentry->d_lock);
 		/* Start asynchronous writeout of the inode */
 		write_inode_now(d_inode(dentry), 0);
@@ -2989,11 +3115,8 @@ static int nfs_do_access(struct inode *inode, const struct cred *cred, int mask)
 	/*
 	 * Determine which access bits we want to ask for...
 	 */
-	cache.mask = NFS_ACCESS_READ | NFS_ACCESS_MODIFY | NFS_ACCESS_EXTEND;
-	if (nfs_server_capable(inode, NFS_CAP_XATTR)) {
-		cache.mask |= NFS_ACCESS_XAREAD | NFS_ACCESS_XAWRITE |
-		    NFS_ACCESS_XALIST;
-	}
+	cache.mask = NFS_ACCESS_READ | NFS_ACCESS_MODIFY | NFS_ACCESS_EXTEND |
+		     nfs_access_xattr_mask(NFS_SERVER(inode));
 	if (S_ISDIR(inode->i_mode))
 		cache.mask |= NFS_ACCESS_DELETE | NFS_ACCESS_LOOKUP;
 	else