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.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2016, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  */
  31
  32 #include <linux/errno.h>
  33 #include <linux/delay.h>
  34 #include <linux/kernel.h>
  35 #include <linux/mm.h>
  36
  37 #define DEBUG_SUBSYSTEM S_LLITE
  38
  39 #include "llite_internal.h"
  40 #include <lustre_compat.h>
  41
  42 static const struct vm_operations_struct ll_file_vm_ops;
  43
  44 void policy_from_vma(union ldlm_policy_data *policy, struct vm_area_struct *vma,
  45                      unsigned long addr, size_t count)
  46 {
  47         policy->l_extent.start = ((addr - vma->vm_start) & PAGE_MASK) +
  48                                  (vma->vm_pgoff << PAGE_SHIFT);
  49         policy->l_extent.end = (policy->l_extent.start + count - 1) |
  50                                ~PAGE_MASK;
  51 }
  52
  53 struct vm_area_struct *our_vma(struct mm_struct *mm, unsigned long addr,
  54                                size_t count)
  55 {
  56         struct vm_area_struct *vma, *ret = NULL;
  57         ENTRY;
  58
  59         /* mmap_lock must have been held by caller. */
  60         LASSERT(!mmap_write_trylock(mm));
  61
  62         for (vma = find_vma(mm, addr);
  63              vma != NULL && vma->vm_start < (addr + count);
  64              vma = vma->vm_next) {
  65                 if (vma->vm_ops && vma->vm_ops == &ll_file_vm_ops &&
  66                     vma->vm_flags & VM_SHARED) {
  67                         ret = vma;
  68                         break;
  69                 }
  70         }
  71         RETURN(ret);
  72 }
  73
  74 /**
  75  * API independent part for page fault initialization.
  76  * \param env - corespondent lu_env to processing
  77  * \param vma - virtual memory area addressed to page fault
  78  * \param index - page index corespondent to fault.
  79  *
  80  * \return error codes from cl_io_init.
  81  */
  82 static struct cl_io *
  83 ll_fault_io_init(struct lu_env *env, struct vm_area_struct *vma, pgoff_t index)
  84 {
  85         struct file            *file = vma->vm_file;
  86         struct inode           *inode = file_inode(file);
  87         struct cl_io           *io;
  88         struct cl_fault_io     *fio;
  89         int                     rc;
  90         ENTRY;
  91
  92         if (ll_file_nolock(file))
  93                 RETURN(ERR_PTR(-EOPNOTSUPP));
  94
  95 restart:
  96         io = vvp_env_thread_io(env);
  97         io->ci_obj = ll_i2info(inode)->lli_clob;
  98         LASSERT(io->ci_obj != NULL);
  99
 100         fio = &io->u.ci_fault;
 101         fio->ft_index = index;
 102         fio->ft_executable = vma->vm_flags & VM_EXEC;
 103
 104         CDEBUG(D_MMAP,
 105                DFID": vma=%p start=%#lx end=%#lx vm_flags=%#lx idx=%lu\n",
 106                PFID(&ll_i2info(inode)->lli_fid), vma, vma->vm_start,
 107                vma->vm_end, vma->vm_flags, fio->ft_index);
 108
 109         if (vma->vm_flags & VM_SEQ_READ)
 110                 io->ci_seq_read = 1;
 111         else if (vma->vm_flags & VM_RAND_READ)
 112                 io->ci_rand_read = 1;
 113
 114         if (vma->vm_flags & VM_WRITE)
 115                 fio->ft_writable = 1;
 116
 117         rc = cl_io_init(env, io, CIT_FAULT, io->ci_obj);
 118         if (rc == 0) {
 119                 struct vvp_io *vio = vvp_env_io(env);
 120                 struct ll_file_data *fd = file->private_data;
 121
 122                 LASSERT(vio->vui_cl.cis_io == io);
 123
 124                 /* mmap lock must be MANDATORY it has to cache
 125                  * pages. */
 126                 io->ci_lockreq = CILR_MANDATORY;
 127                 vio->vui_fd = fd;
 128         } else {
 129                 cl_io_fini(env, io);
 130                 if (io->ci_need_restart)
 131                         goto restart;
 132
 133                 io = ERR_PTR(rc);
 134         }
 135
 136         RETURN(io);
 137 }
 138
 139 /* Sharing code of page_mkwrite method for rhel5 and rhel6 */
 140 static int ll_page_mkwrite0(struct vm_area_struct *vma, struct page *vmpage,
 141                             bool *retry)
 142 {
 143         struct lu_env           *env;
 144         struct cl_io            *io;
 145         struct vvp_io           *vio;
 146         int                      result;
 147         __u16                    refcheck;
 148         sigset_t old, new;
 149         struct inode             *inode = NULL;
 150         struct ll_inode_info     *lli;
 151         ENTRY;
 152
 153         LASSERT(vmpage != NULL);
 154         env = cl_env_get(&refcheck);
 155         if (IS_ERR(env))
 156                 RETURN(PTR_ERR(env));
 157
 158         io = ll_fault_io_init(env, vma, vmpage->index);
 159         if (IS_ERR(io))
 160                 GOTO(out, result = PTR_ERR(io));
 161
 162         result = io->ci_result;
 163         if (result < 0)
 164                 GOTO(out_io, result);
 165
 166         io->u.ci_fault.ft_mkwrite = 1;
 167         io->u.ci_fault.ft_writable = 1;
 168
 169         vio = vvp_env_io(env);
 170         vio->u.fault.ft_vma    = vma;
 171         vio->u.fault.ft_vmpage = vmpage;
 172
 173         siginitsetinv(&new, sigmask(SIGKILL) | sigmask(SIGTERM));
 174         sigprocmask(SIG_BLOCK, &new, &old);
 175
 176         inode = vvp_object_inode(io->ci_obj);
 177         lli = ll_i2info(inode);
 178
 179         result = cl_io_loop(env, io);
 180
 181         sigprocmask(SIG_SETMASK, &old, NULL);
 182
 183         if (result == 0) {
 184                 lock_page(vmpage);
 185                 if (vmpage->mapping == NULL) {
 186                         unlock_page(vmpage);
 187
 188                         /* page was truncated and lock was cancelled, return
 189                          * ENODATA so that VM_FAULT_NOPAGE will be returned
 190                          * to handle_mm_fault(). */
 191                         if (result == 0)
 192                                 result = -ENODATA;
 193                 } else if (!PageDirty(vmpage)) {
 194                         /* race, the page has been cleaned by ptlrpcd after
 195                          * it was unlocked, it has to be added into dirty
 196                          * cache again otherwise this soon-to-dirty page won't
 197                          * consume any grants, even worse if this page is being
 198                          * transferred because it will break RPC checksum.
 199                          */
 200                         unlock_page(vmpage);
 201
 202                         CDEBUG(D_MMAP, "Race on page_mkwrite %p/%lu, page has "
 203                                "been written out, retry.\n",
 204                                vmpage, vmpage->index);
 205
 206                         *retry = true;
 207                         result = -EAGAIN;
 208                 }
 209
 210                 if (result == 0)
 211                         set_bit(LLIF_DATA_MODIFIED, &lli->lli_flags);
 212         }
 213         EXIT;
 214
 215 out_io:
 216         cl_io_fini(env, io);
 217 out:
 218         cl_env_put(env, &refcheck);
 219         CDEBUG(D_MMAP, "%s mkwrite with %d\n", current->comm, result);
 220         LASSERT(ergo(result == 0, PageLocked(vmpage)));
 221
 222         /* if page has been unmapped, presumably due to lock reclaim for
 223          * concurrent usage, add some delay before retrying to prevent
 224          * entering live-lock situation with competitors
 225          */
 226         if (result == -ENODATA && inode != NULL) {
 227                 CDEBUG(D_MMAP, "delaying new page-fault for inode %p to "
 228                                "prevent live-lock\n", inode);
 229                 msleep(10);
 230         }
 231
 232         return result;
 233 }
 234
 235 static inline int to_fault_error(int result)
 236 {
 237         switch(result) {
 238         case 0:
 239                 result = VM_FAULT_LOCKED;
 240                 break;
 241         case -ENOMEM:
 242                 result = VM_FAULT_OOM;
 243                 break;
 244         default:
 245                 result = VM_FAULT_SIGBUS;
 246                 break;
 247         }
 248         return result;
 249 }
 250
 251 /**
 252  * Lustre implementation of a vm_operations_struct::fault() method, called by
 253  * VM to server page fault (both in kernel and user space).
 254  *
 255  * \param vma - is virtiual area struct related to page fault
 256  * \param vmf - structure which describe type and address where hit fault
 257  *
 258  * \return allocated and filled _locked_ page for address
 259  * \retval VM_FAULT_ERROR on general error
 260  * \retval NOPAGE_OOM not have memory for allocate new page
 261  */
 262 static vm_fault_t ll_fault0(struct vm_area_struct *vma, struct vm_fault *vmf)
 263 {
 264         struct lu_env           *env;
 265         struct cl_io            *io;
 266         struct vvp_io           *vio = NULL;
 267         struct page             *vmpage;
 268         int                      result = 0;
 269         int                      fault_ret = 0;
 270         __u16                    refcheck;
 271         ENTRY;
 272
 273         env = cl_env_get(&refcheck);
 274         if (IS_ERR(env))
 275                 RETURN(PTR_ERR(env));
 276
 277         if (ll_sbi_has_fast_read(ll_i2sbi(file_inode(vma->vm_file)))) {
 278                 /* do fast fault */
 279                 bool has_retry = vmf->flags & FAULT_FLAG_RETRY_NOWAIT;
 280
 281                 /* To avoid loops, instruct downstream to not drop mmap_sem */
 282                 vmf->flags |= FAULT_FLAG_RETRY_NOWAIT;
 283                 ll_cl_add(vma->vm_file, env, NULL, LCC_MMAP);
 284                 fault_ret = ll_filemap_fault(vma, vmf);
 285                 ll_cl_remove(vma->vm_file, env);
 286                 if (!has_retry)
 287                         vmf->flags &= ~FAULT_FLAG_RETRY_NOWAIT;
 288
 289                 /* - If there is no error, then the page was found in cache and
 290                  *   uptodate;
 291                  * - If VM_FAULT_RETRY is set, the page existed but failed to
 292                  *   lock. We will try slow path to avoid loops.
 293                  * - Otherwise, it should try normal fault under DLM lock. */
 294                 if (!(fault_ret & VM_FAULT_RETRY) &&
 295                     !(fault_ret & VM_FAULT_ERROR))
 296                         GOTO(out, result = 0);
 297
 298                 fault_ret = 0;
 299         }
 300
 301         io = ll_fault_io_init(env, vma, vmf->pgoff);
 302         if (IS_ERR(io))
 303                 GOTO(out, result = 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.ft_vmf = vmf;
 311                 vio->u.fault.ft_flags = 0;
 312                 vio->u.fault.ft_flags_valid = 0;
 313
 314                 /* May call ll_readpage() */
 315                 ll_cl_add(vma->vm_file, env, io, LCC_MMAP);
 316
 317                 result = cl_io_loop(env, io);
 318
 319                 ll_cl_remove(vma->vm_file, env);
 320
 321                 /* ft_flags are only valid if we reached
 322                  * the call to filemap_fault */
 323                 if (vio->u.fault.ft_flags_valid)
 324                         fault_ret = vio->u.fault.ft_flags;
 325
 326                 vmpage = vio->u.fault.ft_vmpage;
 327                 if (result != 0 && vmpage != NULL) {
 328                         put_page(vmpage);
 329                         vmf->page = NULL;
 330                 }
 331         }
 332         cl_io_fini(env, io);
 333
 334 out:
 335         cl_env_put(env, &refcheck);
 336         if (result != 0 && !(fault_ret & VM_FAULT_RETRY))
 337                 fault_ret |= to_fault_error(result);
 338
 339         CDEBUG(D_MMAP, "%s fault %d/%d\n", current->comm, fault_ret, result);
 340         RETURN(fault_ret);
 341 }
 342
 343 #ifdef HAVE_VM_OPS_USE_VM_FAULT_ONLY
 344 static vm_fault_t ll_fault(struct vm_fault *vmf)
 345 {
 346         struct vm_area_struct *vma = vmf->vma;
 347 #else
 348 static vm_fault_t ll_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 349 {
 350 #endif
 351         int count = 0;
 352         bool printed = false;
 353         bool cached;
 354         vm_fault_t result;
 355         ktime_t kstart = ktime_get();
 356         sigset_t old, new;
 357
 358         result = pcc_fault(vma, vmf, &cached);
 359         if (cached)
 360                 goto out;
 361
 362         CDEBUG(D_MMAP, DFID": vma=%p start=%#lx end=%#lx vm_flags=%#lx\n",
 363                PFID(&ll_i2info(file_inode(vma->vm_file))->lli_fid),
 364                vma, vma->vm_start, vma->vm_end, vma->vm_flags);
 365
 366         /* Only SIGKILL and SIGTERM is allowed for fault/nopage/mkwrite
 367          * so that it can be killed by admin but not cause segfault by
 368          * other signals.
 369          */
 370         siginitsetinv(&new, sigmask(SIGKILL) | sigmask(SIGTERM));
 371         sigprocmask(SIG_BLOCK, &new, &old);
 372
 373         /* make sure offset is not a negative number */
 374         if (vmf->pgoff > (MAX_LFS_FILESIZE >> PAGE_SHIFT))
 375                 return VM_FAULT_SIGBUS;
 376
 377 restart:
 378         result = ll_fault0(vma, vmf);
 379         if (vmf->page &&
 380             !(result & (VM_FAULT_RETRY | VM_FAULT_ERROR | VM_FAULT_LOCKED))) {
 381                 struct page *vmpage = vmf->page;
 382
 383                 /* check if this page has been truncated */
 384                 lock_page(vmpage);
 385                 if (unlikely(vmpage->mapping == NULL)) { /* unlucky */
 386                         unlock_page(vmpage);
 387                         put_page(vmpage);
 388                         vmf->page = NULL;
 389
 390                         if (!printed && ++count > 16) {
 391                                 CWARN("the page is under heavy contention, maybe your app(%s) needs revising :-)\n",
 392                                       current->comm);
 393                                 printed = true;
 394                         }
 395
 396                         goto restart;
 397                 }
 398
 399                 result |= VM_FAULT_LOCKED;
 400         }
 401         sigprocmask(SIG_SETMASK, &old, NULL);
 402
 403 out:
 404         if (vmf->page && result == VM_FAULT_LOCKED) {
 405                 ll_rw_stats_tally(ll_i2sbi(file_inode(vma->vm_file)),
 406                                   current->pid, vma->vm_file->private_data,
 407                                   cl_offset(NULL, vmf->page->index), PAGE_SIZE,
 408                                   READ);
 409                 ll_stats_ops_tally(ll_i2sbi(file_inode(vma->vm_file)),
 410                                    LPROC_LL_FAULT,
 411                                    ktime_us_delta(ktime_get(), kstart));
 412         }
 413
 414         return result;
 415 }
 416
 417 #ifdef HAVE_VM_OPS_USE_VM_FAULT_ONLY
 418 static vm_fault_t ll_page_mkwrite(struct vm_fault *vmf)
 419 {
 420         struct vm_area_struct *vma = vmf->vma;
 421 #else
 422 static vm_fault_t ll_page_mkwrite(struct vm_area_struct *vma,
 423                                   struct vm_fault *vmf)
 424 {
 425 #endif
 426         int count = 0;
 427         bool printed = false;
 428         bool retry;
 429         bool cached;
 430         ktime_t kstart = ktime_get();
 431         vm_fault_t result;
 432
 433         result = pcc_page_mkwrite(vma, vmf, &cached);
 434         if (cached)
 435                 goto out;
 436
 437         file_update_time(vma->vm_file);
 438         do {
 439                 retry = false;
 440                 result = ll_page_mkwrite0(vma, vmf->page, &retry);
 441
 442                 if (!printed && ++count > 16) {
 443                         const struct dentry *de = file_dentry(vma->vm_file);
 444
 445                         CWARN("app(%s): the page %lu of file "DFID" is under heavy contention\n",
 446                               current->comm, vmf->pgoff,
 447                               PFID(ll_inode2fid(de->d_inode)));
 448                         printed = true;
 449                 }
 450         } while (retry);
 451
 452         switch (result) {
 453         case 0:
 454                 LASSERT(PageLocked(vmf->page));
 455                 result = VM_FAULT_LOCKED;
 456                 break;
 457         case -ENODATA:
 458         case -EFAULT:
 459                 result = VM_FAULT_NOPAGE;
 460                 break;
 461         case -ENOMEM:
 462                 result = VM_FAULT_OOM;
 463                 break;
 464         case -EAGAIN:
 465                 result = VM_FAULT_RETRY;
 466                 break;
 467         default:
 468                 result = VM_FAULT_SIGBUS;
 469                 break;
 470         }
 471
 472 out:
 473         if (result == VM_FAULT_LOCKED) {
 474                 ll_rw_stats_tally(ll_i2sbi(file_inode(vma->vm_file)),
 475                                   current->pid, vma->vm_file->private_data,
 476                                   cl_offset(NULL, vmf->page->index), PAGE_SIZE,
 477                                   WRITE);
 478                 ll_stats_ops_tally(ll_i2sbi(file_inode(vma->vm_file)),
 479                                    LPROC_LL_MKWRITE,
 480                                    ktime_us_delta(ktime_get(), kstart));
 481         }
 482
 483         return result;
 484 }
 485
 486 /**
 487  *  To avoid cancel the locks covering mmapped region for lock cache pressure,
 488  *  we track the mapped vma count in vvp_object::vob_mmap_cnt.
 489  */
 490 static void ll_vm_open(struct vm_area_struct * vma)
 491 {
 492         struct inode *inode    = file_inode(vma->vm_file);
 493         struct vvp_object *vob = cl_inode2vvp(inode);
 494
 495         ENTRY;
 496         LASSERT(atomic_read(&vob->vob_mmap_cnt) >= 0);
 497         atomic_inc(&vob->vob_mmap_cnt);
 498         pcc_vm_open(vma);
 499         EXIT;
 500 }
 501
 502 /**
 503  * Dual to ll_vm_open().
 504  */
 505 static void ll_vm_close(struct vm_area_struct *vma)
 506 {
 507         struct inode      *inode = file_inode(vma->vm_file);
 508         struct vvp_object *vob   = cl_inode2vvp(inode);
 509
 510         ENTRY;
 511         atomic_dec(&vob->vob_mmap_cnt);
 512         LASSERT(atomic_read(&vob->vob_mmap_cnt) >= 0);
 513         pcc_vm_close(vma);
 514         EXIT;
 515 }
 516
 517 static const struct vm_operations_struct ll_file_vm_ops = {
 518         .fault                  = ll_fault,
 519         .page_mkwrite           = ll_page_mkwrite,
 520         .open                   = ll_vm_open,
 521         .close                  = ll_vm_close,
 522 };
 523
 524 int ll_file_mmap(struct file *file, struct vm_area_struct * vma)
 525 {
 526         struct inode *inode = file_inode(file);
 527         ktime_t kstart = ktime_get();
 528         bool cached;
 529         int rc;
 530
 531         ENTRY;
 532         CDEBUG(D_VFSTRACE | D_MMAP,
 533                "VFS_Op: fid="DFID" vma=%p start=%#lx end=%#lx vm_flags=%#lx\n",
 534                PFID(&ll_i2info(inode)->lli_fid),
 535                vma, vma->vm_start, vma->vm_end, vma->vm_flags);
 536
 537         if (ll_file_nolock(file))
 538                 RETURN(-EOPNOTSUPP);
 539
 540         rc = pcc_file_mmap(file, vma, &cached);
 541         if (cached && rc != 0)
 542                 RETURN(rc);
 543
 544         rc = generic_file_mmap(file, vma);
 545         if (rc == 0) {
 546                 vma->vm_ops = &ll_file_vm_ops;
 547                 vma->vm_ops->open(vma);
 548                 /* update the inode's size and mtime */
 549                 if (!cached)
 550                         rc = ll_glimpse_size(inode);
 551         }
 552
 553         if (!rc)
 554                 ll_stats_ops_tally(ll_i2sbi(inode), LPROC_LL_MMAP,
 555                                    ktime_us_delta(ktime_get(), kstart));
 556
 557         RETURN(rc);
 558 }