fs/netfs/main.c

Source file repositories/reference/linux-study-clean/fs/netfs/main.c

File Facts

System
Linux kernel
Corpus path
fs/netfs/main.c
Extension
.c
Size
4536 bytes
Lines
177
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later
/* Miscellaneous bits for the netfs support library.
 *
 * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/module.h>
#include <linux/export.h>
#include <linux/mempool.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include "internal.h"
#define CREATE_TRACE_POINTS
#include <trace/events/netfs.h>

MODULE_DESCRIPTION("Network fs support");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");

EXPORT_TRACEPOINT_SYMBOL(netfs_sreq);

unsigned netfs_debug;
module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");

static struct kmem_cache *netfs_request_slab;
static struct kmem_cache *netfs_subrequest_slab;
mempool_t netfs_request_pool;
mempool_t netfs_subrequest_pool;

#ifdef CONFIG_PROC_FS
LIST_HEAD(netfs_io_requests);
DEFINE_SPINLOCK(netfs_proc_lock);

static const char *netfs_origins[nr__netfs_io_origin] = {
	[NETFS_READAHEAD]		= "RA",
	[NETFS_READPAGE]		= "RP",
	[NETFS_READ_GAPS]		= "RG",
	[NETFS_READ_SINGLE]		= "R1",
	[NETFS_READ_FOR_WRITE]		= "RW",
	[NETFS_UNBUFFERED_READ]		= "UR",
	[NETFS_DIO_READ]		= "DR",
	[NETFS_WRITEBACK]		= "WB",
	[NETFS_WRITEBACK_SINGLE]	= "W1",
	[NETFS_WRITETHROUGH]		= "WT",
	[NETFS_UNBUFFERED_WRITE]	= "UW",
	[NETFS_DIO_WRITE]		= "DW",
	[NETFS_PGPRIV2_COPY_TO_CACHE]	= "2C",
};

/*
 * Generate a list of I/O requests in /proc/fs/netfs/requests
 */
static int netfs_requests_seq_show(struct seq_file *m, void *v)
{
	struct netfs_io_request *rreq;

	if (v == &netfs_io_requests) {
		seq_puts(m,
			 "REQUEST  OR REF FLAG ERR  OPS COVERAGE\n"
			 "======== == === ==== ==== === =========\n"
			 );
		return 0;
	}

	rreq = list_entry(v, struct netfs_io_request, proc_link);
	seq_printf(m,
		   "%08x %s %3d %4lx %4ld %3d @%04llx %llx/%llx",
		   rreq->debug_id,
		   netfs_origins[rreq->origin],
		   refcount_read(&rreq->ref),
		   rreq->flags,
		   rreq->error,
		   0,
		   rreq->start, rreq->submitted, rreq->len);
	seq_putc(m, '\n');
	return 0;
}

static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos)
	__acquires(rcu)
{
	rcu_read_lock();
	return seq_list_start_head(&netfs_io_requests, *_pos);
}

static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t *_pos)
{
	return seq_list_next(v, &netfs_io_requests, _pos);

Annotation

Implementation Notes