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, 2012, 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 <asm/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 != NULL && 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 != NULL);
 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 != NULL)
 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
 155                  * pages. */
 156                 io->ci_lockreq = CILR_MANDATORY;
 157                 cio->cui_fd = fd;
 158         } else {
 159                 LASSERT(rc < 0);
 160                 cl_io_fini(env, io);
 161                 cl_env_nested_put(nest, env);
 162                 io = ERR_PTR(rc);
 163         }
 164
 165         return io;
 166 }
 167
 168 /* Sharing code of page_mkwrite method for rhel5 and rhel6 */
 169 static int ll_page_mkwrite0(struct vm_area_struct *vma, struct page *vmpage,
 170                             bool *retry)
 171 {
 172         struct lu_env      *env;
 173         struct cl_io        *io;
 174         struct vvp_io      *vio;
 175         struct cl_env_nest       nest;
 176         int                   result;
 177         sigset_t             set;
 178         struct inode         *inode;
 179         struct ll_inode_info     *lli;
 180
 181         LASSERT(vmpage != NULL);
 182
 183         io = ll_fault_io_init(vma, &env,  &nest, vmpage->index, NULL);
 184         if (IS_ERR(io)) {
 185                 result = PTR_ERR(io);
 186                 goto out;
 187         }
 188
 189         result = io->ci_result;
 190         if (result < 0)
 191                 goto out_io;
 192
 193         io->u.ci_fault.ft_mkwrite = 1;
 194         io->u.ci_fault.ft_writable = 1;
 195
 196         vio = vvp_env_io(env);
 197         vio->u.fault.ft_vma    = vma;
 198         vio->u.fault.ft_vmpage = vmpage;
 199
 200         set = cfs_block_sigsinv(sigmask(SIGKILL) | sigmask(SIGTERM));
 201
 202         /* we grab lli_trunc_sem to exclude truncate case.
 203          * Otherwise, we could add dirty pages into osc cache
 204          * while truncate is on-going. */
 205         inode = ccc_object_inode(io->ci_obj);
 206         lli = ll_i2info(inode);
 207         down_read(&lli->lli_trunc_sem);
 208
 209         result = cl_io_loop(env, io);
 210
 211         up_read(&lli->lli_trunc_sem);
 212
 213         cfs_restore_sigs(set);
 214
 215         if (result == 0) {
 216                 struct inode *inode = file_inode(vma->vm_file);
 217                 struct ll_inode_info *lli = ll_i2info(inode);
 218
 219                 lock_page(vmpage);
 220                 if (vmpage->mapping == NULL) {
 221                         unlock_page(vmpage);
 222
 223                         /* page was truncated and lock was cancelled, return
 224                          * ENODATA so that VM_FAULT_NOPAGE will be returned
 225                          * to handle_mm_fault(). */
 226                         if (result == 0)
 227                                 result = -ENODATA;
 228                 } else if (!PageDirty(vmpage)) {
 229                         /* race, the page has been cleaned by ptlrpcd after
 230                          * it was unlocked, it has to be added into dirty
 231                          * cache again otherwise this soon-to-dirty page won't
 232                          * consume any grants, even worse if this page is being
 233                          * transferred because it will break RPC checksum.
 234                          */
 235                         unlock_page(vmpage);
 236
 237                         CDEBUG(D_MMAP, "Race on page_mkwrite %p/%lu, page has been written out, retry.\n",
 238                                vmpage, vmpage->index);
 239
 240                         *retry = true;
 241                         result = -EAGAIN;
 242                 }
 243
 244                 if (result == 0) {
 245                         spin_lock(&lli->lli_lock);
 246                         lli->lli_flags |= LLIF_DATA_MODIFIED;
 247                         spin_unlock(&lli->lli_lock);
 248                 }
 249         }
 250
 251 out_io:
 252         cl_io_fini(env, io);
 253         cl_env_nested_put(&nest, env);
 254 out:
 255         CDEBUG(D_MMAP, "%s mkwrite with %d\n", current->comm, result);
 256         LASSERT(ergo(result == 0, PageLocked(vmpage)));
 257
 258         return result;
 259 }
 260
 261
 262
 263 static inline int to_fault_error(int result)
 264 {
 265         switch (result) {
 266         case 0:
 267                 result = VM_FAULT_LOCKED;
 268                 break;
 269         case -EFAULT:
 270                 result = VM_FAULT_NOPAGE;
 271                 break;
 272         case -ENOMEM:
 273                 result = VM_FAULT_OOM;
 274                 break;
 275         default:
 276                 result = VM_FAULT_SIGBUS;
 277                 break;
 278         }
 279         return result;
 280 }
 281
 282 /**
 283  * Lustre implementation of a vm_operations_struct::fault() method, called by
 284  * VM to server page fault (both in kernel and user space).
 285  *
 286  * \param vma - is virtual area struct related to page fault
 287  * \param vmf - structure which describe type and address where hit fault
 288  *
 289  * \return allocated and filled _locked_ page for address
 290  * \retval VM_FAULT_ERROR on general error
 291  * \retval NOPAGE_OOM not have memory for allocate new page
 292  */
 293 static int ll_fault0(struct vm_area_struct *vma, struct vm_fault *vmf)
 294 {
 295         struct lu_env      *env;
 296         struct cl_io        *io;
 297         struct vvp_io      *vio = NULL;
 298         struct page          *vmpage;
 299         unsigned long       ra_flags;
 300         struct cl_env_nest       nest;
 301         int                   result;
 302         int                   fault_ret = 0;
 303
 304         io = ll_fault_io_init(vma, &env,  &nest, vmf->pgoff, &ra_flags);
 305         if (IS_ERR(io))
 306                 return to_fault_error(PTR_ERR(io));
 307
 308         result = io->ci_result;
 309         if (result == 0) {
 310                 vio = vvp_env_io(env);
 311                 vio->u.fault.ft_vma       = vma;
 312                 vio->u.fault.ft_vmpage    = NULL;
 313                 vio->u.fault.fault.ft_vmf = vmf;
 314                 vio->u.fault.fault.ft_flags = 0;
 315                 vio->u.fault.fault.ft_flags_valid = 0;
 316
 317                 result = cl_io_loop(env, io);
 318
 319                 /* ft_flags are only valid if we reached
 320                  * the call to filemap_fault */
 321                 if (vio->u.fault.fault.ft_flags_valid)
 322                         fault_ret = vio->u.fault.fault.ft_flags;
 323
 324                 vmpage = vio->u.fault.ft_vmpage;
 325                 if (result != 0 && vmpage != NULL) {
 326                         page_cache_release(vmpage);
 327                         vmf->page = NULL;
 328                 }
 329         }
 330         cl_io_fini(env, io);
 331         cl_env_nested_put(&nest, env);
 332
 333         vma->vm_flags |= ra_flags;
 334         if (result != 0 && !(fault_ret & VM_FAULT_RETRY))
 335                 fault_ret |= to_fault_error(result);
 336
 337         CDEBUG(D_MMAP, "%s fault %d/%d\n",
 338                current->comm, fault_ret, result);
 339         return fault_ret;
 340 }
 341
 342 static int ll_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 343 {
 344         int count = 0;
 345         bool printed = false;
 346         int result;
 347         sigset_t set;
 348
 349         /* Only SIGKILL and SIGTERM is allowed for fault/nopage/mkwrite
 350          * so that it can be killed by admin but not cause segfault by
 351          * other signals. */
 352         set = cfs_block_sigsinv(sigmask(SIGKILL) | sigmask(SIGTERM));
 353
 354 restart:
 355         result = ll_fault0(vma, vmf);
 356         LASSERT(!(result & VM_FAULT_LOCKED));
 357         if (result == 0) {
 358                 struct page *vmpage = vmf->page;
 359
 360                 /* check if this page has been truncated */
 361                 lock_page(vmpage);
 362                 if (unlikely(vmpage->mapping == NULL)) { /* unlucky */
 363                         unlock_page(vmpage);
 364                         page_cache_release(vmpage);
 365                         vmf->page = NULL;
 366
 367                         if (!printed && ++count > 16) {
 368                                 CWARN("the page is under heavy contention, maybe your app(%s) needs revising :-)\n",
 369                                       current->comm);
 370                                 printed = true;
 371                         }
 372
 373                         goto restart;
 374                 }
 375
 376                 result = VM_FAULT_LOCKED;
 377         }
 378         cfs_restore_sigs(set);
 379         return result;
 380 }
 381
 382 static int ll_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 383 {
 384         int count = 0;
 385         bool printed = false;
 386         bool retry;
 387         int result;
 388
 389         do {
 390                 retry = false;
 391                 result = ll_page_mkwrite0(vma, vmf->page, &retry);
 392
 393                 if (!printed && ++count > 16) {
 394                         CWARN("app(%s): the page %lu of file %lu is under heavy contention.\n",
 395                               current->comm, vmf->pgoff,
 396                               file_inode(vma->vm_file)->i_ino);
 397                         printed = true;
 398                 }
 399         } while (retry);
 400
 401         switch (result) {
 402         case 0:
 403                 LASSERT(PageLocked(vmf->page));
 404                 result = VM_FAULT_LOCKED;
 405                 break;
 406         case -ENODATA:
 407         case -EFAULT:
 408                 result = VM_FAULT_NOPAGE;
 409                 break;
 410         case -ENOMEM:
 411                 result = VM_FAULT_OOM;
 412                 break;
 413         case -EAGAIN:
 414                 result = VM_FAULT_RETRY;
 415                 break;
 416         default:
 417                 result = VM_FAULT_SIGBUS;
 418                 break;
 419         }
 420
 421         return result;
 422 }
 423
 424 /**
 425  *  To avoid cancel the locks covering mmapped region for lock cache pressure,
 426  *  we track the mapped vma count in ccc_object::cob_mmap_cnt.
 427  */
 428 static void ll_vm_open(struct vm_area_struct *vma)
 429 {
 430         struct inode *inode    = file_inode(vma->vm_file);
 431         struct ccc_object *vob = cl_inode2ccc(inode);
 432
 433         LASSERT(vma->vm_file);
 434         LASSERT(atomic_read(&vob->cob_mmap_cnt) >= 0);
 435         atomic_inc(&vob->cob_mmap_cnt);
 436 }
 437
 438 /**
 439  * Dual to ll_vm_open().
 440  */
 441 static void ll_vm_close(struct vm_area_struct *vma)
 442 {
 443         struct inode      *inode = file_inode(vma->vm_file);
 444         struct ccc_object *vob   = cl_inode2ccc(inode);
 445
 446         LASSERT(vma->vm_file);
 447         atomic_dec(&vob->cob_mmap_cnt);
 448         LASSERT(atomic_read(&vob->cob_mmap_cnt) >= 0);
 449 }
 450
 451 /* XXX put nice comment here.  talk about __free_pte -> dirty pages and
 452  * nopage's reference passing to the pte */
 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 }