fs/nfs/fscache.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* NFS filesystem cache interface
   3  *
   4  * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #include <linux/init.h>
   9 #include <linux/kernel.h>
  10 #include <linux/sched.h>
  11 #include <linux/mm.h>
  12 #include <linux/nfs_fs.h>
  13 #include <linux/nfs_fs_sb.h>
  14 #include <linux/in6.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/slab.h>
  17 #include <linux/iversion.h>
  18 #include <linux/xarray.h>
  19 #include <linux/fscache.h>
  20 #include <linux/netfs.h>
  21
  22 #include "internal.h"
  23 #include "iostat.h"
  24 #include "fscache.h"
  25 #include "nfstrace.h"
  26
  27 #define NFS_MAX_KEY_LEN 1000
  28
  29 static bool nfs_append_int(char *key, int *_len, unsigned long long x)
  30 {
  31         if (*_len > NFS_MAX_KEY_LEN)
  32                 return false;
  33         if (x == 0)
  34                 key[(*_len)++] = ',';
  35         else
  36                 *_len += sprintf(key + *_len, ",%llx", x);
  37         return true;
  38 }
  39
  40 /*
  41  * Get the per-client index cookie for an NFS client if the appropriate mount
  42  * flag was set
  43  * - We always try and get an index cookie for the client, but get filehandle
  44  *   cookies on a per-superblock basis, depending on the mount flags
  45  */
  46 static bool nfs_fscache_get_client_key(struct nfs_client *clp,
  47                                        char *key, int *_len)
  48 {
  49         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
  50         const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
  51
  52         *_len += snprintf(key + *_len, NFS_MAX_KEY_LEN - *_len,
  53                           ",%u.%u,%x",
  54                           clp->rpc_ops->version,
  55                           clp->cl_minorversion,
  56                           clp->cl_addr.ss_family);
  57
  58         switch (clp->cl_addr.ss_family) {
  59         case AF_INET:
  60                 if (!nfs_append_int(key, _len, sin->sin_port) ||
  61                     !nfs_append_int(key, _len, sin->sin_addr.s_addr))
  62                         return false;
  63                 return true;
  64
  65         case AF_INET6:
  66                 if (!nfs_append_int(key, _len, sin6->sin6_port) ||
  67                     !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[0]) ||
  68                     !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[1]) ||
  69                     !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[2]) ||
  70                     !nfs_append_int(key, _len, sin6->sin6_addr.s6_addr32[3]))
  71                         return false;
  72                 return true;
  73
  74         default:
  75                 printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
  76                        clp->cl_addr.ss_family);
  77                 return false;
  78         }
  79 }
  80
  81 /*
  82  * Get the cache cookie for an NFS superblock.
  83  *
  84  * The default uniquifier is just an empty string, but it may be overridden
  85  * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent
  86  * superblock across an automount point of some nature.
  87  */
  88 int nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen)
  89 {
  90         struct fscache_volume *vcookie;
  91         struct nfs_server *nfss = NFS_SB(sb);
  92         unsigned int len = 3;
  93         char *key;
  94
  95         if (uniq) {
  96                 nfss->fscache_uniq = kmemdup_nul(uniq, ulen, GFP_KERNEL);
  97                 if (!nfss->fscache_uniq)
  98                         return -ENOMEM;
  99         }
 100
 101         key = kmalloc(NFS_MAX_KEY_LEN + 24, GFP_KERNEL);
 102         if (!key)
 103                 return -ENOMEM;
 104
 105         memcpy(key, "nfs", 3);
 106         if (!nfs_fscache_get_client_key(nfss->nfs_client, key, &len) ||
 107             !nfs_append_int(key, &len, nfss->fsid.major) ||
 108             !nfs_append_int(key, &len, nfss->fsid.minor) ||
 109             !nfs_append_int(key, &len, sb->s_flags & NFS_SB_MASK) ||
 110             !nfs_append_int(key, &len, nfss->flags) ||
 111             !nfs_append_int(key, &len, nfss->rsize) ||
 112             !nfs_append_int(key, &len, nfss->wsize) ||
 113             !nfs_append_int(key, &len, nfss->acregmin) ||
 114             !nfs_append_int(key, &len, nfss->acregmax) ||
 115             !nfs_append_int(key, &len, nfss->acdirmin) ||
 116             !nfs_append_int(key, &len, nfss->acdirmax) ||
 117             !nfs_append_int(key, &len, nfss->client->cl_auth->au_flavor))
 118                 goto out;
 119
 120         if (ulen > 0) {
 121                 if (ulen > NFS_MAX_KEY_LEN - len)
 122                         goto out;
 123                 key[len++] = ',';
 124                 memcpy(key + len, uniq, ulen);
 125                 len += ulen;
 126         }
 127         key[len] = 0;
 128
 129         /* create a cache index for looking up filehandles */
 130         vcookie = fscache_acquire_volume(key,
 131                                          NULL, /* preferred_cache */
 132                                          NULL, 0 /* coherency_data */);
 133         if (IS_ERR(vcookie)) {
 134                 if (vcookie != ERR_PTR(-EBUSY)) {
 135                         kfree(key);
 136                         return PTR_ERR(vcookie);
 137                 }
 138                 pr_err("NFS: Cache volume key already in use (%s)\n", key);
 139                 vcookie = NULL;
 140         }
 141         nfss->fscache = vcookie;
 142
 143 out:
 144         kfree(key);
 145         return 0;
 146 }
 147
 148 /*
 149  * release a per-superblock cookie
 150  */
 151 void nfs_fscache_release_super_cookie(struct super_block *sb)
 152 {
 153         struct nfs_server *nfss = NFS_SB(sb);
 154
 155         fscache_relinquish_volume(nfss->fscache, NULL, false);
 156         nfss->fscache = NULL;
 157         kfree(nfss->fscache_uniq);
 158 }
 159
 160 /*
 161  * Initialise the per-inode cache cookie pointer for an NFS inode.
 162  */
 163 void nfs_fscache_init_inode(struct inode *inode)
 164 {
 165         struct nfs_fscache_inode_auxdata auxdata;
 166         struct nfs_server *nfss = NFS_SERVER(inode);
 167         struct nfs_inode *nfsi = NFS_I(inode);
 168
 169         netfs_inode(inode)->cache = NULL;
 170         if (!(nfss->fscache && S_ISREG(inode->i_mode)))
 171                 return;
 172
 173         nfs_fscache_update_auxdata(&auxdata, inode);
 174
 175         netfs_inode(inode)->cache = fscache_acquire_cookie(
 176                                                nfss->fscache,
 177                                                0,
 178                                                nfsi->fh.data, /* index_key */
 179                                                nfsi->fh.size,
 180                                                &auxdata,      /* aux_data */
 181                                                sizeof(auxdata),
 182                                                i_size_read(inode));
 183
 184         if (netfs_inode(inode)->cache)
 185                 mapping_set_release_always(inode->i_mapping);
 186 }
 187
 188 /*
 189  * Release a per-inode cookie.
 190  */
 191 void nfs_fscache_clear_inode(struct inode *inode)
 192 {
 193         fscache_relinquish_cookie(netfs_i_cookie(netfs_inode(inode)), false);
 194         netfs_inode(inode)->cache = NULL;
 195 }
 196
 197 /*
 198  * Enable or disable caching for a file that is being opened as appropriate.
 199  * The cookie is allocated when the inode is initialised, but is not enabled at
 200  * that time.  Enablement is deferred to file-open time to avoid stat() and
 201  * access() thrashing the cache.
 202  *
 203  * For now, with NFS, only regular files that are open read-only will be able
 204  * to use the cache.
 205  *
 206  * We enable the cache for an inode if we open it read-only and it isn't
 207  * currently open for writing.  We disable the cache if the inode is open
 208  * write-only.
 209  *
 210  * The caller uses the file struct to pin i_writecount on the inode before
 211  * calling us when a file is opened for writing, so we can make use of that.
 212  *
 213  * Note that this may be invoked multiple times in parallel by parallel
 214  * nfs_open() functions.
 215  */
 216 void nfs_fscache_open_file(struct inode *inode, struct file *filp)
 217 {
 218         struct nfs_fscache_inode_auxdata auxdata;
 219         struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode));
 220         bool open_for_write = inode_is_open_for_write(inode);
 221
 222         if (!fscache_cookie_valid(cookie))
 223                 return;
 224
 225         fscache_use_cookie(cookie, open_for_write);
 226         if (open_for_write) {
 227                 nfs_fscache_update_auxdata(&auxdata, inode);
 228                 fscache_invalidate(cookie, &auxdata, i_size_read(inode),
 229                                    FSCACHE_INVAL_DIO_WRITE);
 230         }
 231 }
 232 EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
 233
 234 void nfs_fscache_release_file(struct inode *inode, struct file *filp)
 235 {
 236         struct nfs_fscache_inode_auxdata auxdata;
 237         struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode));
 238         loff_t i_size = i_size_read(inode);
 239
 240         nfs_fscache_update_auxdata(&auxdata, inode);
 241         fscache_unuse_cookie(cookie, &auxdata, &i_size);
 242 }
 243
 244 int nfs_netfs_read_folio(struct file *file, struct folio *folio)
 245 {
 246         if (!netfs_inode(folio_inode(folio))->cache)
 247                 return -ENOBUFS;
 248
 249         return netfs_read_folio(file, folio);
 250 }
 251
 252 int nfs_netfs_readahead(struct readahead_control *ractl)
 253 {
 254         struct inode *inode = ractl->mapping->host;
 255
 256         if (!netfs_inode(inode)->cache)
 257                 return -ENOBUFS;
 258
 259         netfs_readahead(ractl);
 260         return 0;
 261 }
 262
 263 static atomic_t nfs_netfs_debug_id;
 264 static int nfs_netfs_init_request(struct netfs_io_request *rreq, struct file *file)
 265 {
 266         if (!file) {
 267                 if (WARN_ON_ONCE(rreq->origin != NETFS_PGPRIV2_COPY_TO_CACHE))
 268                         return -EIO;
 269                 return 0;
 270         }
 271
 272         rreq->netfs_priv = get_nfs_open_context(nfs_file_open_context(file));
 273         rreq->debug_id = atomic_inc_return(&nfs_netfs_debug_id);
 274         /* [DEPRECATED] Use PG_private_2 to mark folio being written to the cache. */
 275         __set_bit(NETFS_RREQ_USE_PGPRIV2, &rreq->flags);
 276         rreq->io_streams[0].sreq_max_len = NFS_SB(rreq->inode->i_sb)->rsize;
 277
 278         return 0;
 279 }
 280
 281 static void nfs_netfs_free_request(struct netfs_io_request *rreq)
 282 {
 283         if (rreq->netfs_priv)
 284                 put_nfs_open_context(rreq->netfs_priv);
 285 }
 286
 287 static struct nfs_netfs_io_data *nfs_netfs_alloc(struct netfs_io_subrequest *sreq)
 288 {
 289         struct nfs_netfs_io_data *netfs;
 290
 291         netfs = kzalloc(sizeof(*netfs), GFP_KERNEL_ACCOUNT);
 292         if (!netfs)
 293                 return NULL;
 294         netfs->sreq = sreq;
 295         refcount_set(&netfs->refcount, 1);
 296         return netfs;
 297 }
 298
 299 static void nfs_netfs_issue_read(struct netfs_io_subrequest *sreq)
 300 {
 301         struct nfs_netfs_io_data        *netfs;
 302         struct nfs_pageio_descriptor    pgio;
 303         struct inode *inode = sreq->rreq->inode;
 304         struct nfs_open_context *ctx = sreq->rreq->netfs_priv;
 305         struct page *page;
 306         unsigned long idx;
 307         pgoff_t start, last;
 308         int err;
 309
 310         start = (sreq->start + sreq->transferred) >> PAGE_SHIFT;
 311         last = ((sreq->start + sreq->len - sreq->transferred - 1) >> PAGE_SHIFT);
 312
 313         nfs_pageio_init_read(&pgio, inode, false,
 314                              &nfs_async_read_completion_ops);
 315
 316         netfs = nfs_netfs_alloc(sreq);
 317         if (!netfs)
 318                 return netfs_read_subreq_terminated(sreq, -ENOMEM, false);
 319
 320         pgio.pg_netfs = netfs; /* used in completion */
 321
 322         xa_for_each_range(&sreq->rreq->mapping->i_pages, idx, page, start, last) {
 323                 /* nfs_read_add_folio() may schedule() due to pNFS layout and other RPCs  */
 324                 err = nfs_read_add_folio(&pgio, ctx, page_folio(page));
 325                 if (err < 0) {
 326                         netfs->error = err;
 327                         goto out;
 328                 }
 329         }
 330 out:
 331         nfs_pageio_complete_read(&pgio);
 332         nfs_netfs_put(netfs);
 333 }
 334
 335 void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr)
 336 {
 337         struct nfs_netfs_io_data        *netfs = hdr->netfs;
 338
 339         if (!netfs)
 340                 return;
 341
 342         nfs_netfs_get(netfs);
 343 }
 344
 345 int nfs_netfs_folio_unlock(struct folio *folio)
 346 {
 347         struct inode *inode = folio->mapping->host;
 348
 349         /*
 350          * If fscache is enabled, netfs will unlock pages.
 351          */
 352         if (netfs_inode(inode)->cache)
 353                 return 0;
 354
 355         return 1;
 356 }
 357
 358 void nfs_netfs_read_completion(struct nfs_pgio_header *hdr)
 359 {
 360         struct nfs_netfs_io_data        *netfs = hdr->netfs;
 361         struct netfs_io_subrequest      *sreq;
 362
 363         if (!netfs)
 364                 return;
 365
 366         sreq = netfs->sreq;
 367         if (test_bit(NFS_IOHDR_EOF, &hdr->flags) &&
 368             sreq->rreq->origin != NETFS_DIO_READ)
 369                 __set_bit(NETFS_SREQ_CLEAR_TAIL, &sreq->flags);
 370
 371         if (hdr->error)
 372                 netfs->error = hdr->error;
 373         else
 374                 atomic64_add(hdr->res.count, &netfs->transferred);
 375
 376         nfs_netfs_put(netfs);
 377         hdr->netfs = NULL;
 378 }
 379
 380 const struct netfs_request_ops nfs_netfs_ops = {
 381         .init_request           = nfs_netfs_init_request,
 382         .free_request           = nfs_netfs_free_request,
 383         .issue_read             = nfs_netfs_issue_read,
 384 };