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Revision 227823d2074da0c138d2abc0074b2dd281bbf923 authored by Dai Ngo on 23 January 2020, 01:45:39 UTC, committed by Anna Schumaker on 04 February 2020, 15:50:44 UTC 
nfs: optimise readdir cache page invalidation
 
When the directory is large and it's being modified by one client
while another client is doing the 'ls -l' on the same directory then
the cache page invalidation from nfs_force_use_readdirplus causes
the reading client to keep restarting READDIRPLUS from cookie 0
which causes the 'ls -l' to take a very long time to complete,
possibly never completing.

Currently when nfs_force_use_readdirplus is called to switch from
READDIR to READDIRPLUS, it invalidates all the cached pages of the
directory. This cache page invalidation causes the next nfs_readdir
to re-read the directory content from cookie 0.

This patch is to optimise the cache invalidation in
nfs_force_use_readdirplus by only truncating the cached pages from
last page index accessed to the end the file. It also marks the
inode to delay invalidating all the cached page of the directory
until the next initial nfs_readdir of the next 'ls' instance.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Trond Myklebust <trond.myklebust@hammerspace.com>
[Anna - Fix conflicts with Trond's readdir patches]
[Anna - Remove redundant call to nfs_zap_mapping()]
[Anna - Replace d_inode(file_dentry(desc->file)) with file_inode(desc->file)]
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
1 parent 93a6ab7
Raw File
auth_none.c 
// SPDX-License-Identifier: GPL-2.0

#include <linux/ceph/ceph_debug.h>

#include <linux/err.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/slab.h>

#include <linux/ceph/decode.h>
#include <linux/ceph/auth.h>

#include "auth_none.h"

static void reset(struct ceph_auth_client *ac)
{
	struct ceph_auth_none_info *xi = ac->private;

	xi->starting = true;
}

static void destroy(struct ceph_auth_client *ac)
{
	kfree(ac->private);
	ac->private = NULL;
}

static int is_authenticated(struct ceph_auth_client *ac)
{
	struct ceph_auth_none_info *xi = ac->private;

	return !xi->starting;
}

static int should_authenticate(struct ceph_auth_client *ac)
{
	struct ceph_auth_none_info *xi = ac->private;

	return xi->starting;
}

static int ceph_auth_none_build_authorizer(struct ceph_auth_client *ac,
					   struct ceph_none_authorizer *au)
{
	void *p = au->buf;
	void *const end = p + sizeof(au->buf);
	int ret;

	ceph_encode_8_safe(&p, end, 1, e_range);
	ret = ceph_auth_entity_name_encode(ac->name, &p, end);
	if (ret < 0)
		return ret;

	ceph_encode_64_safe(&p, end, ac->global_id, e_range);
	au->buf_len = p - (void *)au->buf;
	dout("%s built authorizer len %d\n", __func__, au->buf_len);
	return 0;

e_range:
	return -ERANGE;
}

static int build_request(struct ceph_auth_client *ac, void *buf, void *end)
{
	return 0;
}

/*
 * the generic auth code decode the global_id, and we carry no actual
 * authenticate state, so nothing happens here.
 */
static int handle_reply(struct ceph_auth_client *ac, int result,
			void *buf, void *end)
{
	struct ceph_auth_none_info *xi = ac->private;

	xi->starting = false;
	return result;
}

static void ceph_auth_none_destroy_authorizer(struct ceph_authorizer *a)
{
	kfree(a);
}

/*
 * build an 'authorizer' with our entity_name and global_id.  it is
 * identical for all services we connect to.
 */
static int ceph_auth_none_create_authorizer(
	struct ceph_auth_client *ac, int peer_type,
	struct ceph_auth_handshake *auth)
{
	struct ceph_none_authorizer *au;
	int ret;

	au = kmalloc(sizeof(*au), GFP_NOFS);
	if (!au)
		return -ENOMEM;

	au->base.destroy = ceph_auth_none_destroy_authorizer;

	ret = ceph_auth_none_build_authorizer(ac, au);
	if (ret) {
		kfree(au);
		return ret;
	}

	auth->authorizer = (struct ceph_authorizer *) au;
	auth->authorizer_buf = au->buf;
	auth->authorizer_buf_len = au->buf_len;
	auth->authorizer_reply_buf = au->reply_buf;
	auth->authorizer_reply_buf_len = sizeof (au->reply_buf);

	return 0;
}

static const struct ceph_auth_client_ops ceph_auth_none_ops = {
	.name = "none",
	.reset = reset,
	.destroy = destroy,
	.is_authenticated = is_authenticated,
	.should_authenticate = should_authenticate,
	.build_request = build_request,
	.handle_reply = handle_reply,
	.create_authorizer = ceph_auth_none_create_authorizer,
};

int ceph_auth_none_init(struct ceph_auth_client *ac)
{
	struct ceph_auth_none_info *xi;

	dout("ceph_auth_none_init %p\n", ac);
	xi = kzalloc(sizeof(*xi), GFP_NOFS);
	if (!xi)
		return -ENOMEM;

	xi->starting = true;

	ac->protocol = CEPH_AUTH_NONE;
	ac->private = xi;
	ac->ops = &ceph_auth_none_ops;
	return 0;
}
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