fs/netfs/main.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Miscellaneous bits for the netfs support library.
   3  *
   4  * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/export.h>
  10 #include <linux/proc_fs.h>
  11 #include <linux/seq_file.h>
  12 #include "internal.h"
  13 #define CREATE_TRACE_POINTS
  14 #include <trace/events/netfs.h>
  15
  16 MODULE_DESCRIPTION("Network fs support");
  17 MODULE_AUTHOR("Red Hat, Inc.");
  18 MODULE_LICENSE("GPL");
  19
  20 EXPORT_TRACEPOINT_SYMBOL(netfs_sreq);
  21
  22 unsigned netfs_debug;
  23 module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
  24 MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");
  25
  26 #ifdef CONFIG_PROC_FS
  27 LIST_HEAD(netfs_io_requests);
  28 DEFINE_SPINLOCK(netfs_proc_lock);
  29
  30 static const char *netfs_origins[nr__netfs_io_origin] = {
  31         [NETFS_READAHEAD]               = "RA",
  32         [NETFS_READPAGE]                = "RP",
  33         [NETFS_READ_FOR_WRITE]          = "RW",
  34         [NETFS_WRITEBACK]               = "WB",
  35         [NETFS_WRITETHROUGH]            = "WT",
  36         [NETFS_LAUNDER_WRITE]           = "LW",
  37         [NETFS_UNBUFFERED_WRITE]        = "UW",
  38         [NETFS_DIO_READ]                = "DR",
  39         [NETFS_DIO_WRITE]               = "DW",
  40 };
  41
  42 /*
  43  * Generate a list of I/O requests in /proc/fs/netfs/requests
  44  */
  45 static int netfs_requests_seq_show(struct seq_file *m, void *v)
  46 {
  47         struct netfs_io_request *rreq;
  48
  49         if (v == &netfs_io_requests) {
  50                 seq_puts(m,
  51                          "REQUEST  OR REF FL ERR  OPS COVERAGE\n"
  52                          "======== == === == ==== === =========\n"
  53                          );
  54                 return 0;
  55         }
  56
  57         rreq = list_entry(v, struct netfs_io_request, proc_link);
  58         seq_printf(m,
  59                    "%08x %s %3d %2lx %4d %3d @%04llx %zx/%zx",
  60                    rreq->debug_id,
  61                    netfs_origins[rreq->origin],
  62                    refcount_read(&rreq->ref),
  63                    rreq->flags,
  64                    rreq->error,
  65                    atomic_read(&rreq->nr_outstanding),
  66                    rreq->start, rreq->submitted, rreq->len);
  67         seq_putc(m, '\n');
  68         return 0;
  69 }
  70
  71 static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos)
  72         __acquires(rcu)
  73 {
  74         rcu_read_lock();
  75         return seq_list_start_head(&netfs_io_requests, *_pos);
  76 }
  77
  78 static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t *_pos)
  79 {
  80         return seq_list_next(v, &netfs_io_requests, _pos);
  81 }
  82
  83 static void netfs_requests_seq_stop(struct seq_file *m, void *v)
  84         __releases(rcu)
  85 {
  86         rcu_read_unlock();
  87 }
  88
  89 static const struct seq_operations netfs_requests_seq_ops = {
  90         .start  = netfs_requests_seq_start,
  91         .next   = netfs_requests_seq_next,
  92         .stop   = netfs_requests_seq_stop,
  93         .show   = netfs_requests_seq_show,
  94 };
  95 #endif /* CONFIG_PROC_FS */
  96
  97 static int __init netfs_init(void)
  98 {
  99         int ret = -ENOMEM;
 100
 101         if (!proc_mkdir("fs/netfs", NULL))
 102                 goto error;
 103         if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL,
 104                              &netfs_requests_seq_ops))
 105                 goto error_proc;
 106 #ifdef CONFIG_FSCACHE_STATS
 107         if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
 108                                 netfs_stats_show))
 109                 goto error_proc;
 110 #endif
 111
 112         ret = fscache_init();
 113         if (ret < 0)
 114                 goto error_proc;
 115         return 0;
 116
 117 error_proc:
 118         remove_proc_entry("fs/netfs", NULL);
 119 error:
 120         return ret;
 121 }
 122 fs_initcall(netfs_init);
 123
 124 static void __exit netfs_exit(void)
 125 {
 126         fscache_exit();
 127         remove_proc_entry("fs/netfs", NULL);
 128 }
 129 module_exit(netfs_exit);