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 19 #include "internal.h" 20 #include "iostat.h" 21 #include "fscache.h" 22 23 #define NFSDBG_FACILITY NFSDBG_FSCACHE 24 25 static struct rb_root nfs_fscache_keys = RB_ROOT; 26 static DEFINE_SPINLOCK(nfs_fscache_keys_lock); 27 28 /* 29 * Layout of the key for an NFS server cache object. 30 */ 31 struct nfs_server_key { 32 struct { 33 uint16_t nfsversion; /* NFS protocol version */ 34 uint16_t family; /* address family */ 35 __be16 port; /* IP port */ 36 } hdr; 37 union { 38 struct in_addr ipv4_addr; /* IPv4 address */ 39 struct in6_addr ipv6_addr; /* IPv6 address */ 40 }; 41 } __packed; 42 43 /* 44 * Get the per-client index cookie for an NFS client if the appropriate mount 45 * flag was set 46 * - We always try and get an index cookie for the client, but get filehandle 47 * cookies on a per-superblock basis, depending on the mount flags 48 */ 49 void nfs_fscache_get_client_cookie(struct nfs_client *clp) 50 { 51 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr; 52 const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr; 53 struct nfs_server_key key; 54 uint16_t len = sizeof(key.hdr); 55 56 memset(&key, 0, sizeof(key)); 57 key.hdr.nfsversion = clp->rpc_ops->version; 58 key.hdr.family = clp->cl_addr.ss_family; 59 60 switch (clp->cl_addr.ss_family) { 61 case AF_INET: 62 key.hdr.port = sin->sin_port; 63 key.ipv4_addr = sin->sin_addr; 64 len += sizeof(key.ipv4_addr); 65 break; 66 67 case AF_INET6: 68 key.hdr.port = sin6->sin6_port; 69 key.ipv6_addr = sin6->sin6_addr; 70 len += sizeof(key.ipv6_addr); 71 break; 72 73 default: 74 printk(KERN_WARNING "NFS: Unknown network family '%d'\n", 75 clp->cl_addr.ss_family); 76 clp->fscache = NULL; 77 return; 78 } 79 80 /* create a cache index for looking up filehandles */ 81 clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index, 82 &nfs_fscache_server_index_def, 83 &key, len, 84 NULL, 0, 85 clp, 0, true); 86 dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n", 87 clp, clp->fscache); 88 } 89 90 /* 91 * Dispose of a per-client cookie 92 */ 93 void nfs_fscache_release_client_cookie(struct nfs_client *clp) 94 { 95 dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n", 96 clp, clp->fscache); 97 98 fscache_relinquish_cookie(clp->fscache, NULL, false); 99 clp->fscache = NULL; 100 } 101 102 /* 103 * Get the cache cookie for an NFS superblock. We have to handle 104 * uniquification here because the cache doesn't do it for us. 105 * 106 * The default uniquifier is just an empty string, but it may be overridden 107 * either by the 'fsc=xxx' option to mount, or by inheriting it from the parent 108 * superblock across an automount point of some nature. 109 */ 110 void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int ulen) 111 { 112 struct nfs_fscache_key *key, *xkey; 113 struct nfs_server *nfss = NFS_SB(sb); 114 struct rb_node **p, *parent; 115 int diff; 116 117 nfss->fscache_key = NULL; 118 nfss->fscache = NULL; 119 if (!(nfss->options & NFS_OPTION_FSCACHE)) 120 return; 121 if (!uniq) { 122 uniq = ""; 123 ulen = 1; 124 } 125 126 key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL); 127 if (!key) 128 return; 129 130 key->nfs_client = nfss->nfs_client; 131 key->key.super.s_flags = sb->s_flags & NFS_SB_MASK; 132 key->key.nfs_server.flags = nfss->flags; 133 key->key.nfs_server.rsize = nfss->rsize; 134 key->key.nfs_server.wsize = nfss->wsize; 135 key->key.nfs_server.acregmin = nfss->acregmin; 136 key->key.nfs_server.acregmax = nfss->acregmax; 137 key->key.nfs_server.acdirmin = nfss->acdirmin; 138 key->key.nfs_server.acdirmax = nfss->acdirmax; 139 key->key.nfs_server.fsid = nfss->fsid; 140 key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor; 141 142 key->key.uniq_len = ulen; 143 memcpy(key->key.uniquifier, uniq, ulen); 144 145 spin_lock(&nfs_fscache_keys_lock); 146 p = &nfs_fscache_keys.rb_node; 147 parent = NULL; 148 while (*p) { 149 parent = *p; 150 xkey = rb_entry(parent, struct nfs_fscache_key, node); 151 152 if (key->nfs_client < xkey->nfs_client) 153 goto go_left; 154 if (key->nfs_client > xkey->nfs_client) 155 goto go_right; 156 157 diff = memcmp(&key->key, &xkey->key, sizeof(key->key)); 158 if (diff < 0) 159 goto go_left; 160 if (diff > 0) 161 goto go_right; 162 163 if (key->key.uniq_len == 0) 164 goto non_unique; 165 diff = memcmp(key->key.uniquifier, 166 xkey->key.uniquifier, 167 key->key.uniq_len); 168 if (diff < 0) 169 goto go_left; 170 if (diff > 0) 171 goto go_right; 172 goto non_unique; 173 174 go_left: 175 p = &(*p)->rb_left; 176 continue; 177 go_right: 178 p = &(*p)->rb_right; 179 } 180 181 rb_link_node(&key->node, parent, p); 182 rb_insert_color(&key->node, &nfs_fscache_keys); 183 spin_unlock(&nfs_fscache_keys_lock); 184 nfss->fscache_key = key; 185 186 /* create a cache index for looking up filehandles */ 187 nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache, 188 &nfs_fscache_super_index_def, 189 key, sizeof(*key) + ulen, 190 NULL, 0, 191 nfss, 0, true); 192 dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n", 193 nfss, nfss->fscache); 194 return; 195 196 non_unique: 197 spin_unlock(&nfs_fscache_keys_lock); 198 kfree(key); 199 nfss->fscache_key = NULL; 200 nfss->fscache = NULL; 201 printk(KERN_WARNING "NFS:" 202 " Cache request denied due to non-unique superblock keys\n"); 203 } 204 205 /* 206 * release a per-superblock cookie 207 */ 208 void nfs_fscache_release_super_cookie(struct super_block *sb) 209 { 210 struct nfs_server *nfss = NFS_SB(sb); 211 212 dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n", 213 nfss, nfss->fscache); 214 215 fscache_relinquish_cookie(nfss->fscache, NULL, false); 216 nfss->fscache = NULL; 217 218 if (nfss->fscache_key) { 219 spin_lock(&nfs_fscache_keys_lock); 220 rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys); 221 spin_unlock(&nfs_fscache_keys_lock); 222 kfree(nfss->fscache_key); 223 nfss->fscache_key = NULL; 224 } 225 } 226 227 /* 228 * Initialise the per-inode cache cookie pointer for an NFS inode. 229 */ 230 void nfs_fscache_init_inode(struct inode *inode) 231 { 232 struct nfs_fscache_inode_auxdata auxdata; 233 struct nfs_server *nfss = NFS_SERVER(inode); 234 struct nfs_inode *nfsi = NFS_I(inode); 235 236 nfsi->fscache = NULL; 237 if (!(nfss->fscache && S_ISREG(inode->i_mode))) 238 return; 239 240 memset(&auxdata, 0, sizeof(auxdata)); 241 auxdata.mtime_sec = nfsi->vfs_inode.i_mtime.tv_sec; 242 auxdata.mtime_nsec = nfsi->vfs_inode.i_mtime.tv_nsec; 243 auxdata.ctime_sec = nfsi->vfs_inode.i_ctime.tv_sec; 244 auxdata.ctime_nsec = nfsi->vfs_inode.i_ctime.tv_nsec; 245 246 if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4) 247 auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode); 248 249 nfsi->fscache = fscache_acquire_cookie(NFS_SB(inode->i_sb)->fscache, 250 &nfs_fscache_inode_object_def, 251 nfsi->fh.data, nfsi->fh.size, 252 &auxdata, sizeof(auxdata), 253 nfsi, nfsi->vfs_inode.i_size, false); 254 } 255 256 /* 257 * Release a per-inode cookie. 258 */ 259 void nfs_fscache_clear_inode(struct inode *inode) 260 { 261 struct nfs_fscache_inode_auxdata auxdata; 262 struct nfs_inode *nfsi = NFS_I(inode); 263 struct fscache_cookie *cookie = nfs_i_fscache(inode); 264 265 dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie); 266 267 memset(&auxdata, 0, sizeof(auxdata)); 268 auxdata.mtime_sec = nfsi->vfs_inode.i_mtime.tv_sec; 269 auxdata.mtime_nsec = nfsi->vfs_inode.i_mtime.tv_nsec; 270 auxdata.ctime_sec = nfsi->vfs_inode.i_ctime.tv_sec; 271 auxdata.ctime_nsec = nfsi->vfs_inode.i_ctime.tv_nsec; 272 fscache_relinquish_cookie(cookie, &auxdata, false); 273 nfsi->fscache = NULL; 274 } 275 276 static bool nfs_fscache_can_enable(void *data) 277 { 278 struct inode *inode = data; 279 280 return !inode_is_open_for_write(inode); 281 } 282 283 /* 284 * Enable or disable caching for a file that is being opened as appropriate. 285 * The cookie is allocated when the inode is initialised, but is not enabled at 286 * that time. Enablement is deferred to file-open time to avoid stat() and 287 * access() thrashing the cache. 288 * 289 * For now, with NFS, only regular files that are open read-only will be able 290 * to use the cache. 291 * 292 * We enable the cache for an inode if we open it read-only and it isn't 293 * currently open for writing. We disable the cache if the inode is open 294 * write-only. 295 * 296 * The caller uses the file struct to pin i_writecount on the inode before 297 * calling us when a file is opened for writing, so we can make use of that. 298 * 299 * Note that this may be invoked multiple times in parallel by parallel 300 * nfs_open() functions. 301 */ 302 void nfs_fscache_open_file(struct inode *inode, struct file *filp) 303 { 304 struct nfs_fscache_inode_auxdata auxdata; 305 struct nfs_inode *nfsi = NFS_I(inode); 306 struct fscache_cookie *cookie = nfs_i_fscache(inode); 307 308 if (!fscache_cookie_valid(cookie)) 309 return; 310 311 memset(&auxdata, 0, sizeof(auxdata)); 312 auxdata.mtime_sec = nfsi->vfs_inode.i_mtime.tv_sec; 313 auxdata.mtime_nsec = nfsi->vfs_inode.i_mtime.tv_nsec; 314 auxdata.ctime_sec = nfsi->vfs_inode.i_ctime.tv_sec; 315 auxdata.ctime_nsec = nfsi->vfs_inode.i_ctime.tv_nsec; 316 317 if (inode_is_open_for_write(inode)) { 318 dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi); 319 clear_bit(NFS_INO_FSCACHE, &nfsi->flags); 320 fscache_disable_cookie(cookie, &auxdata, true); 321 fscache_uncache_all_inode_pages(cookie, inode); 322 } else { 323 dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi); 324 fscache_enable_cookie(cookie, &auxdata, nfsi->vfs_inode.i_size, 325 nfs_fscache_can_enable, inode); 326 if (fscache_cookie_enabled(cookie)) 327 set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags); 328 } 329 } 330 EXPORT_SYMBOL_GPL(nfs_fscache_open_file); 331 332 /* 333 * Release the caching state associated with a page, if the page isn't busy 334 * interacting with the cache. 335 * - Returns true (can release page) or false (page busy). 336 */ 337 int nfs_fscache_release_page(struct page *page, gfp_t gfp) 338 { 339 if (PageFsCache(page)) { 340 struct fscache_cookie *cookie = nfs_i_fscache(page->mapping->host); 341 342 BUG_ON(!cookie); 343 dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n", 344 cookie, page, NFS_I(page->mapping->host)); 345 346 if (!fscache_maybe_release_page(cookie, page, gfp)) 347 return 0; 348 349 nfs_inc_fscache_stats(page->mapping->host, 350 NFSIOS_FSCACHE_PAGES_UNCACHED); 351 } 352 353 return 1; 354 } 355 356 /* 357 * Release the caching state associated with a page if undergoing complete page 358 * invalidation. 359 */ 360 void __nfs_fscache_invalidate_page(struct page *page, struct inode *inode) 361 { 362 struct fscache_cookie *cookie = nfs_i_fscache(inode); 363 364 BUG_ON(!cookie); 365 366 dfprintk(FSCACHE, "NFS: fscache invalidatepage (0x%p/0x%p/0x%p)\n", 367 cookie, page, NFS_I(inode)); 368 369 fscache_wait_on_page_write(cookie, page); 370 371 BUG_ON(!PageLocked(page)); 372 fscache_uncache_page(cookie, page); 373 nfs_inc_fscache_stats(page->mapping->host, 374 NFSIOS_FSCACHE_PAGES_UNCACHED); 375 } 376 377 /* 378 * Handle completion of a page being read from the cache. 379 * - Called in process (keventd) context. 380 */ 381 static void nfs_readpage_from_fscache_complete(struct page *page, 382 void *context, 383 int error) 384 { 385 dfprintk(FSCACHE, 386 "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n", 387 page, context, error); 388 389 /* if the read completes with an error, we just unlock the page and let 390 * the VM reissue the readpage */ 391 if (!error) { 392 SetPageUptodate(page); 393 unlock_page(page); 394 } else { 395 error = nfs_readpage_async(context, page->mapping->host, page); 396 if (error) 397 unlock_page(page); 398 } 399 } 400 401 /* 402 * Retrieve a page from fscache 403 */ 404 int __nfs_readpage_from_fscache(struct nfs_open_context *ctx, 405 struct inode *inode, struct page *page) 406 { 407 int ret; 408 409 dfprintk(FSCACHE, 410 "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n", 411 nfs_i_fscache(inode), page, page->index, page->flags, inode); 412 413 ret = fscache_read_or_alloc_page(nfs_i_fscache(inode), 414 page, 415 nfs_readpage_from_fscache_complete, 416 ctx, 417 GFP_KERNEL); 418 419 switch (ret) { 420 case 0: /* read BIO submitted (page in fscache) */ 421 dfprintk(FSCACHE, 422 "NFS: readpage_from_fscache: BIO submitted\n"); 423 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK); 424 return ret; 425 426 case -ENOBUFS: /* inode not in cache */ 427 case -ENODATA: /* page not in cache */ 428 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL); 429 dfprintk(FSCACHE, 430 "NFS: readpage_from_fscache %d\n", ret); 431 return 1; 432 433 default: 434 dfprintk(FSCACHE, "NFS: readpage_from_fscache %d\n", ret); 435 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL); 436 } 437 return ret; 438 } 439 440 /* 441 * Retrieve a set of pages from fscache 442 */ 443 int __nfs_readpages_from_fscache(struct nfs_open_context *ctx, 444 struct inode *inode, 445 struct address_space *mapping, 446 struct list_head *pages, 447 unsigned *nr_pages) 448 { 449 unsigned npages = *nr_pages; 450 int ret; 451 452 dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n", 453 nfs_i_fscache(inode), npages, inode); 454 455 ret = fscache_read_or_alloc_pages(nfs_i_fscache(inode), 456 mapping, pages, nr_pages, 457 nfs_readpage_from_fscache_complete, 458 ctx, 459 mapping_gfp_mask(mapping)); 460 if (*nr_pages < npages) 461 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK, 462 npages); 463 if (*nr_pages > 0) 464 nfs_add_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL, 465 *nr_pages); 466 467 switch (ret) { 468 case 0: /* read submitted to the cache for all pages */ 469 BUG_ON(!list_empty(pages)); 470 BUG_ON(*nr_pages != 0); 471 dfprintk(FSCACHE, 472 "NFS: nfs_getpages_from_fscache: submitted\n"); 473 474 return ret; 475 476 case -ENOBUFS: /* some pages aren't cached and can't be */ 477 case -ENODATA: /* some pages aren't cached */ 478 dfprintk(FSCACHE, 479 "NFS: nfs_getpages_from_fscache: no page: %d\n", ret); 480 return 1; 481 482 default: 483 dfprintk(FSCACHE, 484 "NFS: nfs_getpages_from_fscache: ret %d\n", ret); 485 } 486 487 return ret; 488 } 489 490 /* 491 * Store a newly fetched page in fscache 492 * - PG_fscache must be set on the page 493 */ 494 void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync) 495 { 496 int ret; 497 498 dfprintk(FSCACHE, 499 "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n", 500 nfs_i_fscache(inode), page, page->index, page->flags, sync); 501 502 ret = fscache_write_page(nfs_i_fscache(inode), page, 503 inode->i_size, GFP_KERNEL); 504 dfprintk(FSCACHE, 505 "NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n", 506 page, page->index, page->flags, ret); 507 508 if (ret != 0) { 509 fscache_uncache_page(nfs_i_fscache(inode), page); 510 nfs_inc_fscache_stats(inode, 511 NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL); 512 nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED); 513 } else { 514 nfs_inc_fscache_stats(inode, 515 NFSIOS_FSCACHE_PAGES_WRITTEN_OK); 516 } 517 } 518