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/mempool.h>
  11 #include <linux/proc_fs.h>
  12 #include <linux/seq_file.h>
  13 #include "internal.h"
  14 #define CREATE_TRACE_POINTS
  15 #include <trace/events/netfs.h>
  16
  17 MODULE_DESCRIPTION("Network fs support");
  18 MODULE_AUTHOR("Red Hat, Inc.");
  19 MODULE_LICENSE("GPL");
  20
  21 EXPORT_TRACEPOINT_SYMBOL(netfs_sreq);
  22
  23 unsigned netfs_debug;
  24 module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
  25 MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");
  26
  27 static struct kmem_cache *netfs_request_slab;
  28 static struct kmem_cache *netfs_subrequest_slab;
  29 mempool_t netfs_request_pool;
  30 mempool_t netfs_subrequest_pool;
  31
  32 #ifdef CONFIG_PROC_FS
  33 LIST_HEAD(netfs_io_requests);
  34 DEFINE_SPINLOCK(netfs_proc_lock);
  35
  36 static const char *netfs_origins[nr__netfs_io_origin] = {
  37         [NETFS_READAHEAD]               = "RA",
  38         [NETFS_READPAGE]                = "RP",
  39         [NETFS_READ_GAPS]               = "RG",
  40         [NETFS_READ_FOR_WRITE]          = "RW",
  41         [NETFS_DIO_READ]                = "DR",
  42         [NETFS_WRITEBACK]               = "WB",
  43         [NETFS_WRITETHROUGH]            = "WT",
  44         [NETFS_UNBUFFERED_WRITE]        = "UW",
  45         [NETFS_DIO_WRITE]               = "DW",
  46         [NETFS_PGPRIV2_COPY_TO_CACHE]   = "2C",
  47 };
  48
  49 /*
  50  * Generate a list of I/O requests in /proc/fs/netfs/requests
  51  */
  52 static int netfs_requests_seq_show(struct seq_file *m, void *v)
  53 {
  54         struct netfs_io_request *rreq;
  55
  56         if (v == &netfs_io_requests) {
  57                 seq_puts(m,
  58                          "REQUEST  OR REF FL ERR  OPS COVERAGE\n"
  59                          "======== == === == ==== === =========\n"
  60                          );
  61                 return 0;
  62         }
  63
  64         rreq = list_entry(v, struct netfs_io_request, proc_link);
  65         seq_printf(m,
  66                    "%08x %s %3d %2lx %4ld %3d @%04llx %llx/%llx",
  67                    rreq->debug_id,
  68                    netfs_origins[rreq->origin],
  69                    refcount_read(&rreq->ref),
  70                    rreq->flags,
  71                    rreq->error,
  72                    atomic_read(&rreq->nr_outstanding),
  73                    rreq->start, rreq->submitted, rreq->len);
  74         seq_putc(m, '\n');
  75         return 0;
  76 }
  77
  78 static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos)
  79         __acquires(rcu)
  80 {
  81         rcu_read_lock();
  82         return seq_list_start_head(&netfs_io_requests, *_pos);
  83 }
  84
  85 static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t *_pos)
  86 {
  87         return seq_list_next(v, &netfs_io_requests, _pos);
  88 }
  89
  90 static void netfs_requests_seq_stop(struct seq_file *m, void *v)
  91         __releases(rcu)
  92 {
  93         rcu_read_unlock();
  94 }
  95
  96 static const struct seq_operations netfs_requests_seq_ops = {
  97         .start  = netfs_requests_seq_start,
  98         .next   = netfs_requests_seq_next,
  99         .stop   = netfs_requests_seq_stop,
 100         .show   = netfs_requests_seq_show,
 101 };
 102 #endif /* CONFIG_PROC_FS */
 103
 104 static int __init netfs_init(void)
 105 {
 106         int ret = -ENOMEM;
 107
 108         netfs_request_slab = kmem_cache_create("netfs_request",
 109                                                sizeof(struct netfs_io_request), 0,
 110                                                SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
 111                                                NULL);
 112         if (!netfs_request_slab)
 113                 goto error_req;
 114
 115         if (mempool_init_slab_pool(&netfs_request_pool, 100, netfs_request_slab) < 0)
 116                 goto error_reqpool;
 117
 118         netfs_subrequest_slab = kmem_cache_create("netfs_subrequest",
 119                                                   sizeof(struct netfs_io_subrequest), 0,
 120                                                   SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
 121                                                   NULL);
 122         if (!netfs_subrequest_slab)
 123                 goto error_subreq;
 124
 125         if (mempool_init_slab_pool(&netfs_subrequest_pool, 100, netfs_subrequest_slab) < 0)
 126                 goto error_subreqpool;
 127
 128         if (!proc_mkdir("fs/netfs", NULL))
 129                 goto error_proc;
 130         if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL,
 131                              &netfs_requests_seq_ops))
 132                 goto error_procfile;
 133 #ifdef CONFIG_FSCACHE_STATS
 134         if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
 135                                 netfs_stats_show))
 136                 goto error_procfile;
 137 #endif
 138
 139         ret = fscache_init();
 140         if (ret < 0)
 141                 goto error_fscache;
 142         return 0;
 143
 144 error_fscache:
 145 error_procfile:
 146         remove_proc_subtree("fs/netfs", NULL);
 147 error_proc:
 148         mempool_exit(&netfs_subrequest_pool);
 149 error_subreqpool:
 150         kmem_cache_destroy(netfs_subrequest_slab);
 151 error_subreq:
 152         mempool_exit(&netfs_request_pool);
 153 error_reqpool:
 154         kmem_cache_destroy(netfs_request_slab);
 155 error_req:
 156         return ret;
 157 }
 158 fs_initcall(netfs_init);
 159
 160 static void __exit netfs_exit(void)
 161 {
 162         fscache_exit();
 163         remove_proc_subtree("fs/netfs", NULL);
 164         mempool_exit(&netfs_subrequest_pool);
 165         kmem_cache_destroy(netfs_subrequest_slab);
 166         mempool_exit(&netfs_request_pool);
 167         kmem_cache_destroy(netfs_request_slab);
 168 }
 169 module_exit(netfs_exit);