linux/fs/netfs/main.c
David Howells 16af134ca4 netfs: Extend the netfs_io_*request structs to handle writes
Modify the netfs_io_request struct to act as a point around which writes
can be coordinated.  It represents and pins a range of pages that need
writing and a list of regions of dirty data in that range of pages.

If RMW is required, the original data can be downloaded into the bounce
buffer, decrypted if necessary, the modifications made, then the modified
data can be reencrypted/recompressed and sent back to the server.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
2023-12-28 09:45:19 +00:00

123 lines
2.8 KiB
C

// 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/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");
unsigned netfs_debug;
module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");
#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_FOR_WRITE] = "RW",
[NETFS_WRITEBACK] = "WB",
};
/*
* 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 FL ERR OPS COVERAGE\n"
"======== == === == ==== === =========\n"
);
return 0;
}
rreq = list_entry(v, struct netfs_io_request, proc_link);
seq_printf(m,
"%08x %s %3d %2lx %4d %3d @%04llx %zx/%zx",
rreq->debug_id,
netfs_origins[rreq->origin],
refcount_read(&rreq->ref),
rreq->flags,
rreq->error,
atomic_read(&rreq->nr_outstanding),
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);
}
static void netfs_requests_seq_stop(struct seq_file *m, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
static const struct seq_operations netfs_requests_seq_ops = {
.start = netfs_requests_seq_start,
.next = netfs_requests_seq_next,
.stop = netfs_requests_seq_stop,
.show = netfs_requests_seq_show,
};
#endif /* CONFIG_PROC_FS */
static int __init netfs_init(void)
{
int ret = -ENOMEM;
if (!proc_mkdir("fs/netfs", NULL))
goto error;
if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL,
&netfs_requests_seq_ops))
goto error_proc;
#ifdef CONFIG_FSCACHE_STATS
if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
netfs_stats_show))
goto error_proc;
#endif
ret = fscache_init();
if (ret < 0)
goto error_proc;
return 0;
error_proc:
remove_proc_entry("fs/netfs", NULL);
error:
return ret;
}
fs_initcall(netfs_init);
static void __exit netfs_exit(void)
{
fscache_exit();
remove_proc_entry("fs/netfs", NULL);
}
module_exit(netfs_exit);