drivers/staging/lustre/lustre/llite/llite_mmap.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2011, 2015, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  */
  36
  37 #include <linux/kernel.h>
  38 #include <linux/mm.h>
  39 #include <linux/string.h>
  40 #include <linux/stat.h>
  41 #include <linux/errno.h>
  42 #include <linux/unistd.h>
  43 #include <linux/uaccess.h>
  44
  45 #include <linux/fs.h>
  46 #include <linux/pagemap.h>
  47
  48 #define DEBUG_SUBSYSTEM S_LLITE
  49
  50 #include "../include/lustre_lite.h"
  51 #include "llite_internal.h"
  52 #include "../include/linux/lustre_compat25.h"
  53
  54 static const struct vm_operations_struct ll_file_vm_ops;
  55
  56 void policy_from_vma(ldlm_policy_data_t *policy,
  57                      struct vm_area_struct *vma, unsigned long addr,
  58                      size_t count)
  59 {
  60         policy->l_extent.start = ((addr - vma->vm_start) & CFS_PAGE_MASK) +
  61                                  (vma->vm_pgoff << PAGE_CACHE_SHIFT);
  62         policy->l_extent.end = (policy->l_extent.start + count - 1) |
  63                                ~CFS_PAGE_MASK;
  64 }
  65
  66 struct vm_area_struct *our_vma(struct mm_struct *mm, unsigned long addr,
  67                                size_t count)
  68 {
  69         struct vm_area_struct *vma, *ret = NULL;
  70
  71         /* mmap_sem must have been held by caller. */
  72         LASSERT(!down_write_trylock(&mm->mmap_sem));
  73
  74         for (vma = find_vma(mm, addr);
  75             vma && vma->vm_start < (addr + count); vma = vma->vm_next) {
  76                 if (vma->vm_ops && vma->vm_ops == &ll_file_vm_ops &&
  77                     vma->vm_flags & VM_SHARED) {
  78                         ret = vma;
  79                         break;
  80                 }
  81         }
  82         return ret;
  83 }
  84
  85 /**
  86  * API independent part for page fault initialization.
  87  * \param vma - virtual memory area addressed to page fault
  88  * \param env - corespondent lu_env to processing
  89  * \param nest - nested level
  90  * \param index - page index corespondent to fault.
  91  * \parm ra_flags - vma readahead flags.
  92  *
  93  * \return allocated and initialized env for fault operation.
  94  * \retval EINVAL if env can't allocated
  95  * \return other error codes from cl_io_init.
  96  */
  97 static struct cl_io *
  98 ll_fault_io_init(struct vm_area_struct *vma, struct lu_env **env_ret,
  99                  struct cl_env_nest *nest, pgoff_t index,
 100                  unsigned long *ra_flags)
 101 {
 102         struct file            *file = vma->vm_file;
 103         struct inode           *inode = file_inode(file);
 104         struct cl_io           *io;
 105         struct cl_fault_io     *fio;
 106         struct lu_env          *env;
 107         int                     rc;
 108
 109         *env_ret = NULL;
 110         if (ll_file_nolock(file))
 111                 return ERR_PTR(-EOPNOTSUPP);
 112
 113         /*
 114          * page fault can be called when lustre IO is
 115          * already active for the current thread, e.g., when doing read/write
 116          * against user level buffer mapped from Lustre buffer. To avoid
 117          * stomping on existing context, optionally force an allocation of a new
 118          * one.
 119          */
 120         env = cl_env_nested_get(nest);
 121         if (IS_ERR(env))
 122                 return ERR_PTR(-EINVAL);
 123
 124         *env_ret = env;
 125
 126         io = ccc_env_thread_io(env);
 127         io->ci_obj = ll_i2info(inode)->lli_clob;
 128         LASSERT(io->ci_obj);
 129
 130         fio = &io->u.ci_fault;
 131         fio->ft_index      = index;
 132         fio->ft_executable = vma->vm_flags&VM_EXEC;
 133
 134         /*
 135          * disable VM_SEQ_READ and use VM_RAND_READ to make sure that
 136          * the kernel will not read other pages not covered by ldlm in
 137          * filemap_nopage. we do our readahead in ll_readpage.
 138          */
 139         if (ra_flags)
 140                 *ra_flags = vma->vm_flags & (VM_RAND_READ|VM_SEQ_READ);
 141         vma->vm_flags &= ~VM_SEQ_READ;
 142         vma->vm_flags |= VM_RAND_READ;
 143
 144         CDEBUG(D_MMAP, "vm_flags: %lx (%lu %d)\n", vma->vm_flags,
 145                fio->ft_index, fio->ft_executable);
 146
 147         rc = cl_io_init(env, io, CIT_FAULT, io->ci_obj);
 148         if (rc == 0) {
 149                 struct ccc_io *cio = ccc_env_io(env);
 150                 struct ll_file_data *fd = LUSTRE_FPRIVATE(file);
 151
 152                 LASSERT(cio->cui_cl.cis_io == io);
 153
 154                 /* mmap lock must be MANDATORY it has to cache pages. */
 155                 io->ci_lockreq = CILR_MANDATORY;
 156                 cio->cui_fd = fd;
 157         } else {
 158                 LASSERT(rc < 0);
 159                 cl_io_fini(env, io);
 160                 cl_env_nested_put(nest, env);
 161                 io = ERR_PTR(rc);
 162         }
 163
 164         return io;
 165 }
 166
 167 /* Sharing code of page_mkwrite method for rhel5 and rhel6 */
 168 static int ll_page_mkwrite0(struct vm_area_struct *vma, struct page *vmpage,
 169                             bool *retry)
 170 {
 171         struct lu_env      *env;
 172         struct cl_io        *io;
 173         struct vvp_io      *vio;
 174         struct cl_env_nest       nest;
 175         int                   result;
 176         sigset_t             set;
 177         struct inode         *inode;
 178         struct ll_inode_info     *lli;
 179
 180         io = ll_fault_io_init(vma, &env,  &nest, vmpage->index, NULL);
 181         if (IS_ERR(io)) {
 182                 result = PTR_ERR(io);
 183                 goto out;
 184         }
 185
 186         result = io->ci_result;
 187         if (result < 0)
 188                 goto out_io;
 189
 190         io->u.ci_fault.ft_mkwrite = 1;
 191         io->u.ci_fault.ft_writable = 1;
 192
 193         vio = vvp_env_io(env);
 194         vio->u.fault.ft_vma    = vma;
 195         vio->u.fault.ft_vmpage = vmpage;
 196
 197         set = cfs_block_sigsinv(sigmask(SIGKILL) | sigmask(SIGTERM));
 198
 199         /* we grab lli_trunc_sem to exclude truncate case.
 200          * Otherwise, we could add dirty pages into osc cache
 201          * while truncate is on-going.
 202          */
 203         inode = ccc_object_inode(io->ci_obj);
 204         lli = ll_i2info(inode);
 205         down_read(&lli->lli_trunc_sem);
 206
 207         result = cl_io_loop(env, io);
 208
 209         up_read(&lli->lli_trunc_sem);
 210
 211         cfs_restore_sigs(set);
 212
 213         if (result == 0) {
 214                 struct inode *inode = file_inode(vma->vm_file);
 215                 struct ll_inode_info *lli = ll_i2info(inode);
 216
 217                 lock_page(vmpage);
 218                 if (!vmpage->mapping) {
 219                         unlock_page(vmpage);
 220
 221                         /* page was truncated and lock was cancelled, return
 222                          * ENODATA so that VM_FAULT_NOPAGE will be returned
 223                          * to handle_mm_fault().
 224                          */
 225                         if (result == 0)
 226                                 result = -ENODATA;
 227                 } else if (!PageDirty(vmpage)) {
 228                         /* race, the page has been cleaned by ptlrpcd after
 229                          * it was unlocked, it has to be added into dirty
 230                          * cache again otherwise this soon-to-dirty page won't
 231                          * consume any grants, even worse if this page is being
 232                          * transferred because it will break RPC checksum.
 233                          */
 234                         unlock_page(vmpage);
 235
 236                         CDEBUG(D_MMAP, "Race on page_mkwrite %p/%lu, page has been written out, retry.\n",
 237                                vmpage, vmpage->index);
 238
 239                         *retry = true;
 240                         result = -EAGAIN;
 241                 }
 242
 243                 if (result == 0) {
 244                         spin_lock(&lli->lli_lock);
 245                         lli->lli_flags |= LLIF_DATA_MODIFIED;
 246                         spin_unlock(&lli->lli_lock);
 247                 }
 248         }
 249
 250 out_io:
 251         cl_io_fini(env, io);
 252         cl_env_nested_put(&nest, env);
 253 out:
 254         CDEBUG(D_MMAP, "%s mkwrite with %d\n", current->comm, result);
 255         LASSERT(ergo(result == 0, PageLocked(vmpage)));
 256
 257         return result;
 258 }
 259
 260 static inline int to_fault_error(int result)
 261 {
 262         switch (result) {
 263         case 0:
 264                 result = VM_FAULT_LOCKED;
 265                 break;
 266         case -EFAULT:
 267                 result = VM_FAULT_NOPAGE;
 268                 break;
 269         case -ENOMEM:
 270                 result = VM_FAULT_OOM;
 271                 break;
 272         default:
 273                 result = VM_FAULT_SIGBUS;
 274                 break;
 275         }
 276         return result;
 277 }
 278
 279 /**
 280  * Lustre implementation of a vm_operations_struct::fault() method, called by
 281  * VM to server page fault (both in kernel and user space).
 282  *
 283  * \param vma - is virtual area struct related to page fault
 284  * \param vmf - structure which describe type and address where hit fault
 285  *
 286  * \return allocated and filled _locked_ page for address
 287  * \retval VM_FAULT_ERROR on general error
 288  * \retval NOPAGE_OOM not have memory for allocate new page
 289  */
 290 static int ll_fault0(struct vm_area_struct *vma, struct vm_fault *vmf)
 291 {
 292         struct lu_env      *env;
 293         struct cl_io        *io;
 294         struct vvp_io      *vio = NULL;
 295         struct page          *vmpage;
 296         unsigned long       ra_flags;
 297         struct cl_env_nest       nest;
 298         int                   result;
 299         int                   fault_ret = 0;
 300
 301         io = ll_fault_io_init(vma, &env,  &nest, vmf->pgoff, &ra_flags);
 302         if (IS_ERR(io))
 303                 return to_fault_error(PTR_ERR(io));
 304
 305         result = io->ci_result;
 306         if (result == 0) {
 307                 vio = vvp_env_io(env);
 308                 vio->u.fault.ft_vma       = vma;
 309                 vio->u.fault.ft_vmpage    = NULL;
 310                 vio->u.fault.fault.ft_vmf = vmf;
 311                 vio->u.fault.fault.ft_flags = 0;
 312                 vio->u.fault.fault.ft_flags_valid = false;
 313
 314                 result = cl_io_loop(env, io);
 315
 316                 /* ft_flags are only valid if we reached
 317                  * the call to filemap_fault
 318                  */
 319                 if (vio->u.fault.fault.ft_flags_valid)
 320                         fault_ret = vio->u.fault.fault.ft_flags;
 321
 322                 vmpage = vio->u.fault.ft_vmpage;
 323                 if (result != 0 && vmpage) {
 324                         page_cache_release(vmpage);
 325                         vmf->page = NULL;
 326                 }
 327         }
 328         cl_io_fini(env, io);
 329         cl_env_nested_put(&nest, env);
 330
 331         vma->vm_flags |= ra_flags;
 332         if (result != 0 && !(fault_ret & VM_FAULT_RETRY))
 333                 fault_ret |= to_fault_error(result);
 334
 335         CDEBUG(D_MMAP, "%s fault %d/%d\n",
 336                current->comm, fault_ret, result);
 337         return fault_ret;
 338 }
 339
 340 static int ll_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 341 {
 342         int count = 0;
 343         bool printed = false;
 344         int result;
 345         sigset_t set;
 346
 347         /* Only SIGKILL and SIGTERM are allowed for fault/nopage/mkwrite
 348          * so that it can be killed by admin but not cause segfault by
 349          * other signals.
 350          */
 351         set = cfs_block_sigsinv(sigmask(SIGKILL) | sigmask(SIGTERM));
 352
 353 restart:
 354         result = ll_fault0(vma, vmf);
 355         LASSERT(!(result & VM_FAULT_LOCKED));
 356         if (result == 0) {
 357                 struct page *vmpage = vmf->page;
 358
 359                 /* check if this page has been truncated */
 360                 lock_page(vmpage);
 361                 if (unlikely(!vmpage->mapping)) { /* unlucky */
 362                         unlock_page(vmpage);
 363                         page_cache_release(vmpage);
 364                         vmf->page = NULL;
 365
 366                         if (!printed && ++count > 16) {
 367                                 CWARN("the page is under heavy contention, maybe your app(%s) needs revising :-)\n",
 368                                       current->comm);
 369                                 printed = true;
 370                         }
 371
 372                         goto restart;
 373                 }
 374
 375                 result = VM_FAULT_LOCKED;
 376         }
 377         cfs_restore_sigs(set);
 378         return result;
 379 }
 380
 381 static int ll_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 382 {
 383         int count = 0;
 384         bool printed = false;
 385         bool retry;
 386         int result;
 387
 388         do {
 389                 retry = false;
 390                 result = ll_page_mkwrite0(vma, vmf->page, &retry);
 391
 392                 if (!printed && ++count > 16) {
 393                         CWARN("app(%s): the page %lu of file %lu is under heavy contention.\n",
 394                               current->comm, vmf->pgoff,
 395                               file_inode(vma->vm_file)->i_ino);
 396                         printed = true;
 397                 }
 398         } while (retry);
 399
 400         switch (result) {
 401         case 0:
 402                 LASSERT(PageLocked(vmf->page));
 403                 result = VM_FAULT_LOCKED;
 404                 break;
 405         case -ENODATA:
 406         case -EFAULT:
 407                 result = VM_FAULT_NOPAGE;
 408                 break;
 409         case -ENOMEM:
 410                 result = VM_FAULT_OOM;
 411                 break;
 412         case -EAGAIN:
 413                 result = VM_FAULT_RETRY;
 414                 break;
 415         default:
 416                 result = VM_FAULT_SIGBUS;
 417                 break;
 418         }
 419
 420         return result;
 421 }
 422
 423 /**
 424  *  To avoid cancel the locks covering mmapped region for lock cache pressure,
 425  *  we track the mapped vma count in ccc_object::cob_mmap_cnt.
 426  */
 427 static void ll_vm_open(struct vm_area_struct *vma)
 428 {
 429         struct inode *inode    = file_inode(vma->vm_file);
 430         struct ccc_object *vob = cl_inode2ccc(inode);
 431
 432         LASSERT(vma->vm_file);
 433         LASSERT(atomic_read(&vob->cob_mmap_cnt) >= 0);
 434         atomic_inc(&vob->cob_mmap_cnt);
 435 }
 436
 437 /**
 438  * Dual to ll_vm_open().
 439  */
 440 static void ll_vm_close(struct vm_area_struct *vma)
 441 {
 442         struct inode      *inode = file_inode(vma->vm_file);
 443         struct ccc_object *vob   = cl_inode2ccc(inode);
 444
 445         LASSERT(vma->vm_file);
 446         atomic_dec(&vob->cob_mmap_cnt);
 447         LASSERT(atomic_read(&vob->cob_mmap_cnt) >= 0);
 448 }
 449
 450 /* XXX put nice comment here.  talk about __free_pte -> dirty pages and
 451  * nopage's reference passing to the pte
 452  */
 453 int ll_teardown_mmaps(struct address_space *mapping, __u64 first, __u64 last)
 454 {
 455         int rc = -ENOENT;
 456
 457         LASSERTF(last > first, "last %llu first %llu\n", last, first);
 458         if (mapping_mapped(mapping)) {
 459                 rc = 0;
 460                 unmap_mapping_range(mapping, first + PAGE_CACHE_SIZE - 1,
 461                                     last - first + 1, 0);
 462         }
 463
 464         return rc;
 465 }
 466
 467 static const struct vm_operations_struct ll_file_vm_ops = {
 468         .fault                  = ll_fault,
 469         .page_mkwrite           = ll_page_mkwrite,
 470         .open                   = ll_vm_open,
 471         .close                  = ll_vm_close,
 472 };
 473
 474 int ll_file_mmap(struct file *file, struct vm_area_struct *vma)
 475 {
 476         struct inode *inode = file_inode(file);
 477         int rc;
 478
 479         if (ll_file_nolock(file))
 480                 return -EOPNOTSUPP;
 481
 482         ll_stats_ops_tally(ll_i2sbi(inode), LPROC_LL_MAP, 1);
 483         rc = generic_file_mmap(file, vma);
 484         if (rc == 0) {
 485                 vma->vm_ops = &ll_file_vm_ops;
 486                 vma->vm_ops->open(vma);
 487                 /* update the inode's size and mtime */
 488                 rc = ll_glimpse_size(inode);
 489         }
 490
 491         return rc;
 492 }