fs/cifs/file.c

   1 /*
   2  *   fs/cifs/file.c
   3  *
   4  *   vfs operations that deal with files
   5  *
   6  *   Copyright (C) International Business Machines  Corp., 2002,2010
   7  *   Author(s): Steve French (sfrench@us.ibm.com)
   8  *              Jeremy Allison (jra@samba.org)
   9  *
  10  *   This library is free software; you can redistribute it and/or modify
  11  *   it under the terms of the GNU Lesser General Public License as published
  12  *   by the Free Software Foundation; either version 2.1 of the License, or
  13  *   (at your option) any later version.
  14  *
  15  *   This library is distributed in the hope that it will be useful,
  16  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  18  *   the GNU Lesser General Public License for more details.
  19  *
  20  *   You should have received a copy of the GNU Lesser General Public License
  21  *   along with this library; if not, write to the Free Software
  22  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  */
  24 #include <linux/fs.h>
  25 #include <linux/backing-dev.h>
  26 #include <linux/stat.h>
  27 #include <linux/fcntl.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/pagevec.h>
  30 #include <linux/writeback.h>
  31 #include <linux/task_io_accounting_ops.h>
  32 #include <linux/delay.h>
  33 #include <linux/mount.h>
  34 #include <linux/slab.h>
  35 #include <linux/swap.h>
  36 #include <asm/div64.h>
  37 #include "cifsfs.h"
  38 #include "cifspdu.h"
  39 #include "cifsglob.h"
  40 #include "cifsproto.h"
  41 #include "cifs_unicode.h"
  42 #include "cifs_debug.h"
  43 #include "cifs_fs_sb.h"
  44 #include "fscache.h"
  45
  46
  47 static inline int cifs_convert_flags(unsigned int flags)
  48 {
  49         if ((flags & O_ACCMODE) == O_RDONLY)
  50                 return GENERIC_READ;
  51         else if ((flags & O_ACCMODE) == O_WRONLY)
  52                 return GENERIC_WRITE;
  53         else if ((flags & O_ACCMODE) == O_RDWR) {
  54                 /* GENERIC_ALL is too much permission to request
  55                    can cause unnecessary access denied on create */
  56                 /* return GENERIC_ALL; */
  57                 return (GENERIC_READ | GENERIC_WRITE);
  58         }
  59
  60         return (READ_CONTROL | FILE_WRITE_ATTRIBUTES | FILE_READ_ATTRIBUTES |
  61                 FILE_WRITE_EA | FILE_APPEND_DATA | FILE_WRITE_DATA |
  62                 FILE_READ_DATA);
  63 }
  64
  65 static u32 cifs_posix_convert_flags(unsigned int flags)
  66 {
  67         u32 posix_flags = 0;
  68
  69         if ((flags & O_ACCMODE) == O_RDONLY)
  70                 posix_flags = SMB_O_RDONLY;
  71         else if ((flags & O_ACCMODE) == O_WRONLY)
  72                 posix_flags = SMB_O_WRONLY;
  73         else if ((flags & O_ACCMODE) == O_RDWR)
  74                 posix_flags = SMB_O_RDWR;
  75
  76         if (flags & O_CREAT) {
  77                 posix_flags |= SMB_O_CREAT;
  78                 if (flags & O_EXCL)
  79                         posix_flags |= SMB_O_EXCL;
  80         } else if (flags & O_EXCL)
  81                 cifs_dbg(FYI, "Application %s pid %d has incorrectly set O_EXCL flag but not O_CREAT on file open. Ignoring O_EXCL\n",
  82                          current->comm, current->tgid);
  83
  84         if (flags & O_TRUNC)
  85                 posix_flags |= SMB_O_TRUNC;
  86         /* be safe and imply O_SYNC for O_DSYNC */
  87         if (flags & O_DSYNC)
  88                 posix_flags |= SMB_O_SYNC;
  89         if (flags & O_DIRECTORY)
  90                 posix_flags |= SMB_O_DIRECTORY;
  91         if (flags & O_NOFOLLOW)
  92                 posix_flags |= SMB_O_NOFOLLOW;
  93         if (flags & O_DIRECT)
  94                 posix_flags |= SMB_O_DIRECT;
  95
  96         return posix_flags;
  97 }
  98
  99 static inline int cifs_get_disposition(unsigned int flags)
 100 {
 101         if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
 102                 return FILE_CREATE;
 103         else if ((flags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
 104                 return FILE_OVERWRITE_IF;
 105         else if ((flags & O_CREAT) == O_CREAT)
 106                 return FILE_OPEN_IF;
 107         else if ((flags & O_TRUNC) == O_TRUNC)
 108                 return FILE_OVERWRITE;
 109         else
 110                 return FILE_OPEN;
 111 }
 112
 113 int cifs_posix_open(char *full_path, struct inode **pinode,
 114                         struct super_block *sb, int mode, unsigned int f_flags,
 115                         __u32 *poplock, __u16 *pnetfid, unsigned int xid)
 116 {
 117         int rc;
 118         FILE_UNIX_BASIC_INFO *presp_data;
 119         __u32 posix_flags = 0;
 120         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 121         struct cifs_fattr fattr;
 122         struct tcon_link *tlink;
 123         struct cifs_tcon *tcon;
 124
 125         cifs_dbg(FYI, "posix open %s\n", full_path);
 126
 127         presp_data = kzalloc(sizeof(FILE_UNIX_BASIC_INFO), GFP_KERNEL);
 128         if (presp_data == NULL)
 129                 return -ENOMEM;
 130
 131         tlink = cifs_sb_tlink(cifs_sb);
 132         if (IS_ERR(tlink)) {
 133                 rc = PTR_ERR(tlink);
 134                 goto posix_open_ret;
 135         }
 136
 137         tcon = tlink_tcon(tlink);
 138         mode &= ~current_umask();
 139
 140         posix_flags = cifs_posix_convert_flags(f_flags);
 141         rc = CIFSPOSIXCreate(xid, tcon, posix_flags, mode, pnetfid, presp_data,
 142                              poplock, full_path, cifs_sb->local_nls,
 143                              cifs_remap(cifs_sb));
 144         cifs_put_tlink(tlink);
 145
 146         if (rc)
 147                 goto posix_open_ret;
 148
 149         if (presp_data->Type == cpu_to_le32(-1))
 150                 goto posix_open_ret; /* open ok, caller does qpathinfo */
 151
 152         if (!pinode)
 153                 goto posix_open_ret; /* caller does not need info */
 154
 155         cifs_unix_basic_to_fattr(&fattr, presp_data, cifs_sb);
 156
 157         /* get new inode and set it up */
 158         if (*pinode == NULL) {
 159                 cifs_fill_uniqueid(sb, &fattr);
 160                 *pinode = cifs_iget(sb, &fattr);
 161                 if (!*pinode) {
 162                         rc = -ENOMEM;
 163                         goto posix_open_ret;
 164                 }
 165         } else {
 166                 cifs_fattr_to_inode(*pinode, &fattr);
 167         }
 168
 169 posix_open_ret:
 170         kfree(presp_data);
 171         return rc;
 172 }
 173
 174 static int
 175 cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
 176              struct cifs_tcon *tcon, unsigned int f_flags, __u32 *oplock,
 177              struct cifs_fid *fid, unsigned int xid)
 178 {
 179         int rc;
 180         int desired_access;
 181         int disposition;
 182         int create_options = CREATE_NOT_DIR;
 183         FILE_ALL_INFO *buf;
 184         struct TCP_Server_Info *server = tcon->ses->server;
 185         struct cifs_open_parms oparms;
 186
 187         if (!server->ops->open)
 188                 return -ENOSYS;
 189
 190         desired_access = cifs_convert_flags(f_flags);
 191
 192 /*********************************************************************
 193  *  open flag mapping table:
 194  *
 195  *      POSIX Flag            CIFS Disposition
 196  *      ----------            ----------------
 197  *      O_CREAT               FILE_OPEN_IF
 198  *      O_CREAT | O_EXCL      FILE_CREATE
 199  *      O_CREAT | O_TRUNC     FILE_OVERWRITE_IF
 200  *      O_TRUNC               FILE_OVERWRITE
 201  *      none of the above     FILE_OPEN
 202  *
 203  *      Note that there is not a direct match between disposition
 204  *      FILE_SUPERSEDE (ie create whether or not file exists although
 205  *      O_CREAT | O_TRUNC is similar but truncates the existing
 206  *      file rather than creating a new file as FILE_SUPERSEDE does
 207  *      (which uses the attributes / metadata passed in on open call)
 208  *?
 209  *?  O_SYNC is a reasonable match to CIFS writethrough flag
 210  *?  and the read write flags match reasonably.  O_LARGEFILE
 211  *?  is irrelevant because largefile support is always used
 212  *?  by this client. Flags O_APPEND, O_DIRECT, O_DIRECTORY,
 213  *       O_FASYNC, O_NOFOLLOW, O_NONBLOCK need further investigation
 214  *********************************************************************/
 215
 216         disposition = cifs_get_disposition(f_flags);
 217
 218         /* BB pass O_SYNC flag through on file attributes .. BB */
 219
 220         buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 221         if (!buf)
 222                 return -ENOMEM;
 223
 224         if (backup_cred(cifs_sb))
 225                 create_options |= CREATE_OPEN_BACKUP_INTENT;
 226
 227         /* O_SYNC also has bit for O_DSYNC so following check picks up either */
 228         if (f_flags & O_SYNC)
 229                 create_options |= CREATE_WRITE_THROUGH;
 230
 231         if (f_flags & O_DIRECT)
 232                 create_options |= CREATE_NO_BUFFER;
 233
 234         oparms.tcon = tcon;
 235         oparms.cifs_sb = cifs_sb;
 236         oparms.desired_access = desired_access;
 237         oparms.create_options = create_options;
 238         oparms.disposition = disposition;
 239         oparms.path = full_path;
 240         oparms.fid = fid;
 241         oparms.reconnect = false;
 242
 243         rc = server->ops->open(xid, &oparms, oplock, buf);
 244
 245         if (rc)
 246                 goto out;
 247
 248         if (tcon->unix_ext)
 249                 rc = cifs_get_inode_info_unix(&inode, full_path, inode->i_sb,
 250                                               xid);
 251         else
 252                 rc = cifs_get_inode_info(&inode, full_path, buf, inode->i_sb,
 253                                          xid, fid);
 254
 255 out:
 256         kfree(buf);
 257         return rc;
 258 }
 259
 260 static bool
 261 cifs_has_mand_locks(struct cifsInodeInfo *cinode)
 262 {
 263         struct cifs_fid_locks *cur;
 264         bool has_locks = false;
 265
 266         down_read(&cinode->lock_sem);
 267         list_for_each_entry(cur, &cinode->llist, llist) {
 268                 if (!list_empty(&cur->locks)) {
 269                         has_locks = true;
 270                         break;
 271                 }
 272         }
 273         up_read(&cinode->lock_sem);
 274         return has_locks;
 275 }
 276
 277 struct cifsFileInfo *
 278 cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
 279                   struct tcon_link *tlink, __u32 oplock)
 280 {
 281         struct dentry *dentry = file_dentry(file);
 282         struct inode *inode = d_inode(dentry);
 283         struct cifsInodeInfo *cinode = CIFS_I(inode);
 284         struct cifsFileInfo *cfile;
 285         struct cifs_fid_locks *fdlocks;
 286         struct cifs_tcon *tcon = tlink_tcon(tlink);
 287         struct TCP_Server_Info *server = tcon->ses->server;
 288
 289         cfile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 290         if (cfile == NULL)
 291                 return cfile;
 292
 293         fdlocks = kzalloc(sizeof(struct cifs_fid_locks), GFP_KERNEL);
 294         if (!fdlocks) {
 295                 kfree(cfile);
 296                 return NULL;
 297         }
 298
 299         INIT_LIST_HEAD(&fdlocks->locks);
 300         fdlocks->cfile = cfile;
 301         cfile->llist = fdlocks;
 302         down_write(&cinode->lock_sem);
 303         list_add(&fdlocks->llist, &cinode->llist);
 304         up_write(&cinode->lock_sem);
 305
 306         cfile->count = 1;
 307         cfile->pid = current->tgid;
 308         cfile->uid = current_fsuid();
 309         cfile->dentry = dget(dentry);
 310         cfile->f_flags = file->f_flags;
 311         cfile->invalidHandle = false;
 312         cfile->tlink = cifs_get_tlink(tlink);
 313         INIT_WORK(&cfile->oplock_break, cifs_oplock_break);
 314         mutex_init(&cfile->fh_mutex);
 315         spin_lock_init(&cfile->file_info_lock);
 316
 317         cifs_sb_active(inode->i_sb);
 318
 319         /*
 320          * If the server returned a read oplock and we have mandatory brlocks,
 321          * set oplock level to None.
 322          */
 323         if (server->ops->is_read_op(oplock) && cifs_has_mand_locks(cinode)) {
 324                 cifs_dbg(FYI, "Reset oplock val from read to None due to mand locks\n");
 325                 oplock = 0;
 326         }
 327
 328         spin_lock(&tcon->open_file_lock);
 329         if (fid->pending_open->oplock != CIFS_OPLOCK_NO_CHANGE && oplock)
 330                 oplock = fid->pending_open->oplock;
 331         list_del(&fid->pending_open->olist);
 332
 333         fid->purge_cache = false;
 334         server->ops->set_fid(cfile, fid, oplock);
 335
 336         list_add(&cfile->tlist, &tcon->openFileList);
 337
 338         /* if readable file instance put first in list*/
 339         if (file->f_mode & FMODE_READ)
 340                 list_add(&cfile->flist, &cinode->openFileList);
 341         else
 342                 list_add_tail(&cfile->flist, &cinode->openFileList);
 343         spin_unlock(&tcon->open_file_lock);
 344
 345         if (fid->purge_cache)
 346                 cifs_zap_mapping(inode);
 347
 348         file->private_data = cfile;
 349         return cfile;
 350 }
 351
 352 struct cifsFileInfo *
 353 cifsFileInfo_get(struct cifsFileInfo *cifs_file)
 354 {
 355         spin_lock(&cifs_file->file_info_lock);
 356         cifsFileInfo_get_locked(cifs_file);
 357         spin_unlock(&cifs_file->file_info_lock);
 358         return cifs_file;
 359 }
 360
 361 /*
 362  * Release a reference on the file private data. This may involve closing
 363  * the filehandle out on the server. Must be called without holding
 364  * tcon->open_file_lock and cifs_file->file_info_lock.
 365  */
 366 void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
 367 {
 368         struct inode *inode = d_inode(cifs_file->dentry);
 369         struct cifs_tcon *tcon = tlink_tcon(cifs_file->tlink);
 370         struct TCP_Server_Info *server = tcon->ses->server;
 371         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 372         struct super_block *sb = inode->i_sb;
 373         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 374         struct cifsLockInfo *li, *tmp;
 375         struct cifs_fid fid;
 376         struct cifs_pending_open open;
 377         bool oplock_break_cancelled;
 378
 379         spin_lock(&tcon->open_file_lock);
 380
 381         spin_lock(&cifs_file->file_info_lock);
 382         if (--cifs_file->count > 0) {
 383                 spin_unlock(&cifs_file->file_info_lock);
 384                 spin_unlock(&tcon->open_file_lock);
 385                 return;
 386         }
 387         spin_unlock(&cifs_file->file_info_lock);
 388
 389         if (server->ops->get_lease_key)
 390                 server->ops->get_lease_key(inode, &fid);
 391
 392         /* store open in pending opens to make sure we don't miss lease break */
 393         cifs_add_pending_open_locked(&fid, cifs_file->tlink, &open);
 394
 395         /* remove it from the lists */
 396         list_del(&cifs_file->flist);
 397         list_del(&cifs_file->tlist);
 398
 399         if (list_empty(&cifsi->openFileList)) {
 400                 cifs_dbg(FYI, "closing last open instance for inode %p\n",
 401                          d_inode(cifs_file->dentry));
 402                 /*
 403                  * In strict cache mode we need invalidate mapping on the last
 404                  * close  because it may cause a error when we open this file
 405                  * again and get at least level II oplock.
 406                  */
 407                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO)
 408                         set_bit(CIFS_INO_INVALID_MAPPING, &cifsi->flags);
 409                 cifs_set_oplock_level(cifsi, 0);
 410         }
 411
 412         spin_unlock(&tcon->open_file_lock);
 413
 414         oplock_break_cancelled = cancel_work_sync(&cifs_file->oplock_break);
 415
 416         if (!tcon->need_reconnect && !cifs_file->invalidHandle) {
 417                 struct TCP_Server_Info *server = tcon->ses->server;
 418                 unsigned int xid;
 419
 420                 xid = get_xid();
 421                 if (server->ops->close)
 422                         server->ops->close(xid, tcon, &cifs_file->fid);
 423                 _free_xid(xid);
 424         }
 425
 426         if (oplock_break_cancelled)
 427                 cifs_done_oplock_break(cifsi);
 428
 429         cifs_del_pending_open(&open);
 430
 431         /*
 432          * Delete any outstanding lock records. We'll lose them when the file
 433          * is closed anyway.
 434          */
 435         down_write(&cifsi->lock_sem);
 436         list_for_each_entry_safe(li, tmp, &cifs_file->llist->locks, llist) {
 437                 list_del(&li->llist);
 438                 cifs_del_lock_waiters(li);
 439                 kfree(li);
 440         }
 441         list_del(&cifs_file->llist->llist);
 442         kfree(cifs_file->llist);
 443         up_write(&cifsi->lock_sem);
 444
 445         cifs_put_tlink(cifs_file->tlink);
 446         dput(cifs_file->dentry);
 447         cifs_sb_deactive(sb);
 448         kfree(cifs_file);
 449 }
 450
 451 int cifs_open(struct inode *inode, struct file *file)
 452
 453 {
 454         int rc = -EACCES;
 455         unsigned int xid;
 456         __u32 oplock;
 457         struct cifs_sb_info *cifs_sb;
 458         struct TCP_Server_Info *server;
 459         struct cifs_tcon *tcon;
 460         struct tcon_link *tlink;
 461         struct cifsFileInfo *cfile = NULL;
 462         char *full_path = NULL;
 463         bool posix_open_ok = false;
 464         struct cifs_fid fid;
 465         struct cifs_pending_open open;
 466
 467         xid = get_xid();
 468
 469         cifs_sb = CIFS_SB(inode->i_sb);
 470         tlink = cifs_sb_tlink(cifs_sb);
 471         if (IS_ERR(tlink)) {
 472                 free_xid(xid);
 473                 return PTR_ERR(tlink);
 474         }
 475         tcon = tlink_tcon(tlink);
 476         server = tcon->ses->server;
 477
 478         full_path = build_path_from_dentry(file_dentry(file));
 479         if (full_path == NULL) {
 480                 rc = -ENOMEM;
 481                 goto out;
 482         }
 483
 484         cifs_dbg(FYI, "inode = 0x%p file flags are 0x%x for %s\n",
 485                  inode, file->f_flags, full_path);
 486
 487         if (file->f_flags & O_DIRECT &&
 488             cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) {
 489                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
 490                         file->f_op = &cifs_file_direct_nobrl_ops;
 491                 else
 492                         file->f_op = &cifs_file_direct_ops;
 493         }
 494
 495         if (server->oplocks)
 496                 oplock = REQ_OPLOCK;
 497         else
 498                 oplock = 0;
 499
 500         if (!tcon->broken_posix_open && tcon->unix_ext &&
 501             cap_unix(tcon->ses) && (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 502                                 le64_to_cpu(tcon->fsUnixInfo.Capability))) {
 503                 /* can not refresh inode info since size could be stale */
 504                 rc = cifs_posix_open(full_path, &inode, inode->i_sb,
 505                                 cifs_sb->mnt_file_mode /* ignored */,
 506                                 file->f_flags, &oplock, &fid.netfid, xid);
 507                 if (rc == 0) {
 508                         cifs_dbg(FYI, "posix open succeeded\n");
 509                         posix_open_ok = true;
 510                 } else if ((rc == -EINVAL) || (rc == -EOPNOTSUPP)) {
 511                         if (tcon->ses->serverNOS)
 512                                 cifs_dbg(VFS, "server %s of type %s returned unexpected error on SMB posix open, disabling posix open support. Check if server update available.\n",
 513                                          tcon->ses->serverName,
 514                                          tcon->ses->serverNOS);
 515                         tcon->broken_posix_open = true;
 516                 } else if ((rc != -EIO) && (rc != -EREMOTE) &&
 517                          (rc != -EOPNOTSUPP)) /* path not found or net err */
 518                         goto out;
 519                 /*
 520                  * Else fallthrough to retry open the old way on network i/o
 521                  * or DFS errors.
 522                  */
 523         }
 524
 525         if (server->ops->get_lease_key)
 526                 server->ops->get_lease_key(inode, &fid);
 527
 528         cifs_add_pending_open(&fid, tlink, &open);
 529
 530         if (!posix_open_ok) {
 531                 if (server->ops->get_lease_key)
 532                         server->ops->get_lease_key(inode, &fid);
 533
 534                 rc = cifs_nt_open(full_path, inode, cifs_sb, tcon,
 535                                   file->f_flags, &oplock, &fid, xid);
 536                 if (rc) {
 537                         cifs_del_pending_open(&open);
 538                         goto out;
 539                 }
 540         }
 541
 542         cfile = cifs_new_fileinfo(&fid, file, tlink, oplock);
 543         if (cfile == NULL) {
 544                 if (server->ops->close)
 545                         server->ops->close(xid, tcon, &fid);
 546                 cifs_del_pending_open(&open);
 547                 rc = -ENOMEM;
 548                 goto out;
 549         }
 550
 551         cifs_fscache_set_inode_cookie(inode, file);
 552
 553         if ((oplock & CIFS_CREATE_ACTION) && !posix_open_ok && tcon->unix_ext) {
 554                 /*
 555                  * Time to set mode which we can not set earlier due to
 556                  * problems creating new read-only files.
 557                  */
 558                 struct cifs_unix_set_info_args args = {
 559                         .mode   = inode->i_mode,
 560                         .uid    = INVALID_UID, /* no change */
 561                         .gid    = INVALID_GID, /* no change */
 562                         .ctime  = NO_CHANGE_64,
 563                         .atime  = NO_CHANGE_64,
 564                         .mtime  = NO_CHANGE_64,
 565                         .device = 0,
 566                 };
 567                 CIFSSMBUnixSetFileInfo(xid, tcon, &args, fid.netfid,
 568                                        cfile->pid);
 569         }
 570
 571 out:
 572         kfree(full_path);
 573         free_xid(xid);
 574         cifs_put_tlink(tlink);
 575         return rc;
 576 }
 577
 578 static int cifs_push_posix_locks(struct cifsFileInfo *cfile);
 579
 580 /*
 581  * Try to reacquire byte range locks that were released when session
 582  * to server was lost.
 583  */
 584 static int
 585 cifs_relock_file(struct cifsFileInfo *cfile)
 586 {
 587         struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->dentry->d_sb);
 588         struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
 589         struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
 590         int rc = 0;
 591
 592         down_read_nested(&cinode->lock_sem, SINGLE_DEPTH_NESTING);
 593         if (cinode->can_cache_brlcks) {
 594                 /* can cache locks - no need to relock */
 595                 up_read(&cinode->lock_sem);
 596                 return rc;
 597         }
 598
 599         if (cap_unix(tcon->ses) &&
 600             (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
 601             ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
 602                 rc = cifs_push_posix_locks(cfile);
 603         else
 604                 rc = tcon->ses->server->ops->push_mand_locks(cfile);
 605
 606         up_read(&cinode->lock_sem);
 607         return rc;
 608 }
 609
 610 static int
 611 cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 612 {
 613         int rc = -EACCES;
 614         unsigned int xid;
 615         __u32 oplock;
 616         struct cifs_sb_info *cifs_sb;
 617         struct cifs_tcon *tcon;
 618         struct TCP_Server_Info *server;
 619         struct cifsInodeInfo *cinode;
 620         struct inode *inode;
 621         char *full_path = NULL;
 622         int desired_access;
 623         int disposition = FILE_OPEN;
 624         int create_options = CREATE_NOT_DIR;
 625         struct cifs_open_parms oparms;
 626
 627         xid = get_xid();
 628         mutex_lock(&cfile->fh_mutex);
 629         if (!cfile->invalidHandle) {
 630                 mutex_unlock(&cfile->fh_mutex);
 631                 rc = 0;
 632                 free_xid(xid);
 633                 return rc;
 634         }
 635
 636         inode = d_inode(cfile->dentry);
 637         cifs_sb = CIFS_SB(inode->i_sb);
 638         tcon = tlink_tcon(cfile->tlink);
 639         server = tcon->ses->server;
 640
 641         /*
 642          * Can not grab rename sem here because various ops, including those
 643          * that already have the rename sem can end up causing writepage to get
 644          * called and if the server was down that means we end up here, and we
 645          * can never tell if the caller already has the rename_sem.
 646          */
 647         full_path = build_path_from_dentry(cfile->dentry);
 648         if (full_path == NULL) {
 649                 rc = -ENOMEM;
 650                 mutex_unlock(&cfile->fh_mutex);
 651                 free_xid(xid);
 652                 return rc;
 653         }
 654
 655         cifs_dbg(FYI, "inode = 0x%p file flags 0x%x for %s\n",
 656                  inode, cfile->f_flags, full_path);
 657
 658         if (tcon->ses->server->oplocks)
 659                 oplock = REQ_OPLOCK;
 660         else
 661                 oplock = 0;
 662
 663         if (tcon->unix_ext && cap_unix(tcon->ses) &&
 664             (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 665                                 le64_to_cpu(tcon->fsUnixInfo.Capability))) {
 666                 /*
 667                  * O_CREAT, O_EXCL and O_TRUNC already had their effect on the
 668                  * original open. Must mask them off for a reopen.
 669                  */
 670                 unsigned int oflags = cfile->f_flags &
 671                                                 ~(O_CREAT | O_EXCL | O_TRUNC);
 672
 673                 rc = cifs_posix_open(full_path, NULL, inode->i_sb,
 674                                      cifs_sb->mnt_file_mode /* ignored */,
 675                                      oflags, &oplock, &cfile->fid.netfid, xid);
 676                 if (rc == 0) {
 677                         cifs_dbg(FYI, "posix reopen succeeded\n");
 678                         oparms.reconnect = true;
 679                         goto reopen_success;
 680                 }
 681                 /*
 682                  * fallthrough to retry open the old way on errors, especially
 683                  * in the reconnect path it is important to retry hard
 684                  */
 685         }
 686
 687         desired_access = cifs_convert_flags(cfile->f_flags);
 688
 689         if (backup_cred(cifs_sb))
 690                 create_options |= CREATE_OPEN_BACKUP_INTENT;
 691
 692         if (server->ops->get_lease_key)
 693                 server->ops->get_lease_key(inode, &cfile->fid);
 694
 695         oparms.tcon = tcon;
 696         oparms.cifs_sb = cifs_sb;
 697         oparms.desired_access = desired_access;
 698         oparms.create_options = create_options;
 699         oparms.disposition = disposition;
 700         oparms.path = full_path;
 701         oparms.fid = &cfile->fid;
 702         oparms.reconnect = true;
 703
 704         /*
 705          * Can not refresh inode by passing in file_info buf to be returned by
 706          * ops->open and then calling get_inode_info with returned buf since
 707          * file might have write behind data that needs to be flushed and server
 708          * version of file size can be stale. If we knew for sure that inode was
 709          * not dirty locally we could do this.
 710          */
 711         rc = server->ops->open(xid, &oparms, &oplock, NULL);
 712         if (rc == -ENOENT && oparms.reconnect == false) {
 713                 /* durable handle timeout is expired - open the file again */
 714                 rc = server->ops->open(xid, &oparms, &oplock, NULL);
 715                 /* indicate that we need to relock the file */
 716                 oparms.reconnect = true;
 717         }
 718
 719         if (rc) {
 720                 mutex_unlock(&cfile->fh_mutex);
 721                 cifs_dbg(FYI, "cifs_reopen returned 0x%x\n", rc);
 722                 cifs_dbg(FYI, "oplock: %d\n", oplock);
 723                 goto reopen_error_exit;
 724         }
 725
 726 reopen_success:
 727         cfile->invalidHandle = false;
 728         mutex_unlock(&cfile->fh_mutex);
 729         cinode = CIFS_I(inode);
 730
 731         if (can_flush) {
 732                 rc = filemap_write_and_wait(inode->i_mapping);
 733                 mapping_set_error(inode->i_mapping, rc);
 734
 735                 if (tcon->unix_ext)
 736                         rc = cifs_get_inode_info_unix(&inode, full_path,
 737                                                       inode->i_sb, xid);
 738                 else
 739                         rc = cifs_get_inode_info(&inode, full_path, NULL,
 740                                                  inode->i_sb, xid, NULL);
 741         }
 742         /*
 743          * Else we are writing out data to server already and could deadlock if
 744          * we tried to flush data, and since we do not know if we have data that
 745          * would invalidate the current end of file on the server we can not go
 746          * to the server to get the new inode info.
 747          */
 748
 749         /*
 750          * If the server returned a read oplock and we have mandatory brlocks,
 751          * set oplock level to None.
 752          */
 753         if (server->ops->is_read_op(oplock) && cifs_has_mand_locks(cinode)) {
 754                 cifs_dbg(FYI, "Reset oplock val from read to None due to mand locks\n");
 755                 oplock = 0;
 756         }
 757
 758         server->ops->set_fid(cfile, &cfile->fid, oplock);
 759         if (oparms.reconnect)
 760                 cifs_relock_file(cfile);
 761
 762 reopen_error_exit:
 763         kfree(full_path);
 764         free_xid(xid);
 765         return rc;
 766 }
 767
 768 int cifs_close(struct inode *inode, struct file *file)
 769 {
 770         if (file->private_data != NULL) {
 771                 cifsFileInfo_put(file->private_data);
 772                 file->private_data = NULL;
 773         }
 774
 775         /* return code from the ->release op is always ignored */
 776         return 0;
 777 }
 778
 779 void
 780 cifs_reopen_persistent_handles(struct cifs_tcon *tcon)
 781 {
 782         struct cifsFileInfo *open_file;
 783         struct list_head *tmp;
 784         struct list_head *tmp1;
 785         struct list_head tmp_list;
 786
 787         if (!tcon->use_persistent || !tcon->need_reopen_files)
 788                 return;
 789
 790         tcon->need_reopen_files = false;
 791
 792         cifs_dbg(FYI, "Reopen persistent handles");
 793         INIT_LIST_HEAD(&tmp_list);
 794
 795         /* list all files open on tree connection, reopen resilient handles  */
 796         spin_lock(&tcon->open_file_lock);
 797         list_for_each(tmp, &tcon->openFileList) {
 798                 open_file = list_entry(tmp, struct cifsFileInfo, tlist);
 799                 if (!open_file->invalidHandle)
 800                         continue;
 801                 cifsFileInfo_get(open_file);
 802                 list_add_tail(&open_file->rlist, &tmp_list);
 803         }
 804         spin_unlock(&tcon->open_file_lock);
 805
 806         list_for_each_safe(tmp, tmp1, &tmp_list) {
 807                 open_file = list_entry(tmp, struct cifsFileInfo, rlist);
 808                 if (cifs_reopen_file(open_file, false /* do not flush */))
 809                         tcon->need_reopen_files = true;
 810                 list_del_init(&open_file->rlist);
 811                 cifsFileInfo_put(open_file);
 812         }
 813 }
 814
 815 int cifs_closedir(struct inode *inode, struct file *file)
 816 {
 817         int rc = 0;
 818         unsigned int xid;
 819         struct cifsFileInfo *cfile = file->private_data;
 820         struct cifs_tcon *tcon;
 821         struct TCP_Server_Info *server;
 822         char *buf;
 823
 824         cifs_dbg(FYI, "Closedir inode = 0x%p\n", inode);
 825
 826         if (cfile == NULL)
 827                 return rc;
 828
 829         xid = get_xid();
 830         tcon = tlink_tcon(cfile->tlink);
 831         server = tcon->ses->server;
 832
 833         cifs_dbg(FYI, "Freeing private data in close dir\n");
 834         spin_lock(&cfile->file_info_lock);
 835         if (server->ops->dir_needs_close(cfile)) {
 836                 cfile->invalidHandle = true;
 837                 spin_unlock(&cfile->file_info_lock);
 838                 if (server->ops->close_dir)
 839                         rc = server->ops->close_dir(xid, tcon, &cfile->fid);
 840                 else
 841                         rc = -ENOSYS;
 842                 cifs_dbg(FYI, "Closing uncompleted readdir with rc %d\n", rc);
 843                 /* not much we can do if it fails anyway, ignore rc */
 844                 rc = 0;
 845         } else
 846                 spin_unlock(&cfile->file_info_lock);
 847
 848         buf = cfile->srch_inf.ntwrk_buf_start;
 849         if (buf) {
 850                 cifs_dbg(FYI, "closedir free smb buf in srch struct\n");
 851                 cfile->srch_inf.ntwrk_buf_start = NULL;
 852                 if (cfile->srch_inf.smallBuf)
 853                         cifs_small_buf_release(buf);
 854                 else
 855                         cifs_buf_release(buf);
 856         }
 857
 858         cifs_put_tlink(cfile->tlink);
 859         kfree(file->private_data);
 860         file->private_data = NULL;
 861         /* BB can we lock the filestruct while this is going on? */
 862         free_xid(xid);
 863         return rc;
 864 }
 865
 866 static struct cifsLockInfo *
 867 cifs_lock_init(__u64 offset, __u64 length, __u8 type)
 868 {
 869         struct cifsLockInfo *lock =
 870                 kmalloc(sizeof(struct cifsLockInfo), GFP_KERNEL);
 871         if (!lock)
 872                 return lock;
 873         lock->offset = offset;
 874         lock->length = length;
 875         lock->type = type;
 876         lock->pid = current->tgid;
 877         INIT_LIST_HEAD(&lock->blist);
 878         init_waitqueue_head(&lock->block_q);
 879         return lock;
 880 }
 881
 882 void
 883 cifs_del_lock_waiters(struct cifsLockInfo *lock)
 884 {
 885         struct cifsLockInfo *li, *tmp;
 886         list_for_each_entry_safe(li, tmp, &lock->blist, blist) {
 887                 list_del_init(&li->blist);
 888                 wake_up(&li->block_q);
 889         }
 890 }
 891
 892 #define CIFS_LOCK_OP    0
 893 #define CIFS_READ_OP    1
 894 #define CIFS_WRITE_OP   2
 895
 896 /* @rw_check : 0 - no op, 1 - read, 2 - write */
 897 static bool
 898 cifs_find_fid_lock_conflict(struct cifs_fid_locks *fdlocks, __u64 offset,
 899                             __u64 length, __u8 type, struct cifsFileInfo *cfile,
 900                             struct cifsLockInfo **conf_lock, int rw_check)
 901 {
 902         struct cifsLockInfo *li;
 903         struct cifsFileInfo *cur_cfile = fdlocks->cfile;
 904         struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
 905
 906         list_for_each_entry(li, &fdlocks->locks, llist) {
 907                 if (offset + length <= li->offset ||
 908                     offset >= li->offset + li->length)
 909                         continue;
 910                 if (rw_check != CIFS_LOCK_OP && current->tgid == li->pid &&
 911                     server->ops->compare_fids(cfile, cur_cfile)) {
 912                         /* shared lock prevents write op through the same fid */
 913                         if (!(li->type & server->vals->shared_lock_type) ||
 914                             rw_check != CIFS_WRITE_OP)
 915                                 continue;
 916                 }
 917                 if ((type & server->vals->shared_lock_type) &&
 918                     ((server->ops->compare_fids(cfile, cur_cfile) &&
 919                      current->tgid == li->pid) || type == li->type))
 920                         continue;
 921                 if (conf_lock)
 922                         *conf_lock = li;
 923                 return true;
 924         }
 925         return false;
 926 }
 927
 928 bool
 929 cifs_find_lock_conflict(struct cifsFileInfo *cfile, __u64 offset, __u64 length,
 930                         __u8 type, struct cifsLockInfo **conf_lock,
 931                         int rw_check)
 932 {
 933         bool rc = false;
 934         struct cifs_fid_locks *cur;
 935         struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
 936
 937         list_for_each_entry(cur, &cinode->llist, llist) {
 938                 rc = cifs_find_fid_lock_conflict(cur, offset, length, type,
 939                                                  cfile, conf_lock, rw_check);
 940                 if (rc)
 941                         break;
 942         }
 943
 944         return rc;
 945 }
 946
 947 /*
 948  * Check if there is another lock that prevents us to set the lock (mandatory
 949  * style). If such a lock exists, update the flock structure with its
 950  * properties. Otherwise, set the flock type to F_UNLCK if we can cache brlocks
 951  * or leave it the same if we can't. Returns 0 if we don't need to request to
 952  * the server or 1 otherwise.
 953  */
 954 static int
 955 cifs_lock_test(struct cifsFileInfo *cfile, __u64 offset, __u64 length,
 956                __u8 type, struct file_lock *flock)
 957 {
 958         int rc = 0;
 959         struct cifsLockInfo *conf_lock;
 960         struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
 961         struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
 962         bool exist;
 963
 964         down_read(&cinode->lock_sem);
 965
 966         exist = cifs_find_lock_conflict(cfile, offset, length, type,
 967                                         &conf_lock, CIFS_LOCK_OP);
 968         if (exist) {
 969                 flock->fl_start = conf_lock->offset;
 970                 flock->fl_end = conf_lock->offset + conf_lock->length - 1;
 971                 flock->fl_pid = conf_lock->pid;
 972                 if (conf_lock->type & server->vals->shared_lock_type)
 973                         flock->fl_type = F_RDLCK;
 974                 else
 975                         flock->fl_type = F_WRLCK;
 976         } else if (!cinode->can_cache_brlcks)
 977                 rc = 1;
 978         else
 979                 flock->fl_type = F_UNLCK;
 980
 981         up_read(&cinode->lock_sem);
 982         return rc;
 983 }
 984
 985 static void
 986 cifs_lock_add(struct cifsFileInfo *cfile, struct cifsLockInfo *lock)
 987 {
 988         struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
 989         down_write(&cinode->lock_sem);
 990         list_add_tail(&lock->llist, &cfile->llist->locks);
 991         up_write(&cinode->lock_sem);
 992 }
 993
 994 /*
 995  * Set the byte-range lock (mandatory style). Returns:
 996  * 1) 0, if we set the lock and don't need to request to the server;
 997  * 2) 1, if no locks prevent us but we need to request to the server;
 998  * 3) -EACCESS, if there is a lock that prevents us and wait is false.
 999  */
1000 static int
1001 cifs_lock_add_if(struct cifsFileInfo *cfile, struct cifsLockInfo *lock,
1002                  bool wait)
1003 {
1004         struct cifsLockInfo *conf_lock;
1005         struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
1006         bool exist;
1007         int rc = 0;
1008
1009 try_again:
1010         exist = false;
1011         down_write(&cinode->lock_sem);
1012
1013         exist = cifs_find_lock_conflict(cfile, lock->offset, lock->length,
1014                                         lock->type, &conf_lock, CIFS_LOCK_OP);
1015         if (!exist && cinode->can_cache_brlcks) {
1016                 list_add_tail(&lock->llist, &cfile->llist->locks);
1017                 up_write(&cinode->lock_sem);
1018                 return rc;
1019         }
1020
1021         if (!exist)
1022                 rc = 1;
1023         else if (!wait)
1024                 rc = -EACCES;
1025         else {
1026                 list_add_tail(&lock->blist, &conf_lock->blist);
1027                 up_write(&cinode->lock_sem);
1028                 rc = wait_event_interruptible(lock->block_q,
1029                                         (lock->blist.prev == &lock->blist) &&
1030                                         (lock->blist.next == &lock->blist));
1031                 if (!rc)
1032                         goto try_again;
1033                 down_write(&cinode->lock_sem);
1034                 list_del_init(&lock->blist);
1035         }
1036
1037         up_write(&cinode->lock_sem);
1038         return rc;
1039 }
1040
1041 /*
1042  * Check if there is another lock that prevents us to set the lock (posix
1043  * style). If such a lock exists, update the flock structure with its
1044  * properties. Otherwise, set the flock type to F_UNLCK if we can cache brlocks
1045  * or leave it the same if we can't. Returns 0 if we don't need to request to
1046  * the server or 1 otherwise.
1047  */
1048 static int
1049 cifs_posix_lock_test(struct file *file, struct file_lock *flock)
1050 {
1051         int rc = 0;
1052         struct cifsInodeInfo *cinode = CIFS_I(file_inode(file));
1053         unsigned char saved_type = flock->fl_type;
1054
1055         if ((flock->fl_flags & FL_POSIX) == 0)
1056                 return 1;
1057
1058         down_read(&cinode->lock_sem);
1059         posix_test_lock(file, flock);
1060
1061         if (flock->fl_type == F_UNLCK && !cinode->can_cache_brlcks) {
1062                 flock->fl_type = saved_type;
1063                 rc = 1;
1064         }
1065
1066         up_read(&cinode->lock_sem);
1067         return rc;
1068 }
1069
1070 /*
1071  * Set the byte-range lock (posix style). Returns:
1072  * 1) 0, if we set the lock and don't need to request to the server;
1073  * 2) 1, if we need to request to the server;
1074  * 3) <0, if the error occurs while setting the lock.
1075  */
1076 static int
1077 cifs_posix_lock_set(struct file *file, struct file_lock *flock)
1078 {
1079         struct cifsInodeInfo *cinode = CIFS_I(file_inode(file));
1080         int rc = 1;
1081
1082         if ((flock->fl_flags & FL_POSIX) == 0)
1083                 return rc;
1084
1085 try_again:
1086         down_write(&cinode->lock_sem);
1087         if (!cinode->can_cache_brlcks) {
1088                 up_write(&cinode->lock_sem);
1089                 return rc;
1090         }
1091
1092         rc = posix_lock_file(file, flock, NULL);
1093         up_write(&cinode->lock_sem);
1094         if (rc == FILE_LOCK_DEFERRED) {
1095                 rc = wait_event_interruptible(flock->fl_wait, !flock->fl_next);
1096                 if (!rc)
1097                         goto try_again;
1098                 posix_unblock_lock(flock);
1099         }
1100         return rc;
1101 }
1102
1103 int
1104 cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
1105 {
1106         unsigned int xid;
1107         int rc = 0, stored_rc;
1108         struct cifsLockInfo *li, *tmp;
1109         struct cifs_tcon *tcon;
1110         unsigned int num, max_num, max_buf;
1111         LOCKING_ANDX_RANGE *buf, *cur;
1112         static const int types[] = {
1113                 LOCKING_ANDX_LARGE_FILES,
1114                 LOCKING_ANDX_SHARED_LOCK | LOCKING_ANDX_LARGE_FILES
1115         };
1116         int i;
1117
1118         xid = get_xid();
1119         tcon = tlink_tcon(cfile->tlink);
1120
1121         /*
1122          * Accessing maxBuf is racy with cifs_reconnect - need to store value
1123          * and check it for zero before using.
1124          */
1125         max_buf = tcon->ses->server->maxBuf;
1126         if (!max_buf) {
1127                 free_xid(xid);
1128                 return -EINVAL;
1129         }
1130
1131         max_num = (max_buf - sizeof(struct smb_hdr)) /
1132                                                 sizeof(LOCKING_ANDX_RANGE);
1133         buf = kcalloc(max_num, sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
1134         if (!buf) {
1135                 free_xid(xid);
1136                 return -ENOMEM;
1137         }
1138
1139         for (i = 0; i < 2; i++) {
1140                 cur = buf;
1141                 num = 0;
1142                 list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
1143                         if (li->type != types[i])
1144                                 continue;
1145                         cur->Pid = cpu_to_le16(li->pid);
1146                         cur->LengthLow = cpu_to_le32((u32)li->length);
1147                         cur->LengthHigh = cpu_to_le32((u32)(li->length>>32));
1148                         cur->OffsetLow = cpu_to_le32((u32)li->offset);
1149                         cur->OffsetHigh = cpu_to_le32((u32)(li->offset>>32));
1150                         if (++num == max_num) {
1151                                 stored_rc = cifs_lockv(xid, tcon,
1152                                                        cfile->fid.netfid,
1153                                                        (__u8)li->type, 0, num,
1154                                                        buf);
1155                                 if (stored_rc)
1156                                         rc = stored_rc;
1157                                 cur = buf;
1158                                 num = 0;
1159                         } else
1160                                 cur++;
1161                 }
1162
1163                 if (num) {
1164                         stored_rc = cifs_lockv(xid, tcon, cfile->fid.netfid,
1165                                                (__u8)types[i], 0, num, buf);
1166                         if (stored_rc)
1167                                 rc = stored_rc;
1168                 }
1169         }
1170
1171         kfree(buf);
1172         free_xid(xid);
1173         return rc;
1174 }
1175
1176 static __u32
1177 hash_lockowner(fl_owner_t owner)
1178 {
1179         return cifs_lock_secret ^ hash32_ptr((const void *)owner);
1180 }
1181
1182 struct lock_to_push {
1183         struct list_head llist;
1184         __u64 offset;
1185         __u64 length;
1186         __u32 pid;
1187         __u16 netfid;
1188         __u8 type;
1189 };
1190
1191 static int
1192 cifs_push_posix_locks(struct cifsFileInfo *cfile)
1193 {
1194         struct inode *inode = d_inode(cfile->dentry);
1195         struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
1196         struct file_lock *flock;
1197         struct file_lock_context *flctx = inode->i_flctx;
1198         unsigned int count = 0, i;
1199         int rc = 0, xid, type;
1200         struct list_head locks_to_send, *el;
1201         struct lock_to_push *lck, *tmp;
1202         __u64 length;
1203
1204         xid = get_xid();
1205
1206         if (!flctx)
1207                 goto out;
1208
1209         spin_lock(&flctx->flc_lock);
1210         list_for_each(el, &flctx->flc_posix) {
1211                 count++;
1212         }
1213         spin_unlock(&flctx->flc_lock);
1214
1215         INIT_LIST_HEAD(&locks_to_send);
1216
1217         /*
1218          * Allocating count locks is enough because no FL_POSIX locks can be
1219          * added to the list while we are holding cinode->lock_sem that
1220          * protects locking operations of this inode.
1221          */
1222         for (i = 0; i < count; i++) {
1223                 lck = kmalloc(sizeof(struct lock_to_push), GFP_KERNEL);
1224                 if (!lck) {
1225                         rc = -ENOMEM;
1226                         goto err_out;
1227                 }
1228                 list_add_tail(&lck->llist, &locks_to_send);
1229         }
1230
1231         el = locks_to_send.next;
1232         spin_lock(&flctx->flc_lock);
1233         list_for_each_entry(flock, &flctx->flc_posix, fl_list) {
1234                 if (el == &locks_to_send) {
1235                         /*
1236                          * The list ended. We don't have enough allocated
1237                          * structures - something is really wrong.
1238                          */
1239                         cifs_dbg(VFS, "Can't push all brlocks!\n");
1240                         break;
1241                 }
1242                 length = 1 + flock->fl_end - flock->fl_start;
1243                 if (flock->fl_type == F_RDLCK || flock->fl_type == F_SHLCK)
1244                         type = CIFS_RDLCK;
1245                 else
1246                         type = CIFS_WRLCK;
1247                 lck = list_entry(el, struct lock_to_push, llist);
1248                 lck->pid = hash_lockowner(flock->fl_owner);
1249                 lck->netfid = cfile->fid.netfid;
1250                 lck->length = length;
1251                 lck->type = type;
1252                 lck->offset = flock->fl_start;
1253         }
1254         spin_unlock(&flctx->flc_lock);
1255
1256         list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
1257                 int stored_rc;
1258
1259                 stored_rc = CIFSSMBPosixLock(xid, tcon, lck->netfid, lck->pid,
1260                                              lck->offset, lck->length, NULL,
1261                                              lck->type, 0);
1262                 if (stored_rc)
1263                         rc = stored_rc;
1264                 list_del(&lck->llist);
1265                 kfree(lck);
1266         }
1267
1268 out:
1269         free_xid(xid);
1270         return rc;
1271 err_out:
1272         list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
1273                 list_del(&lck->llist);
1274                 kfree(lck);
1275         }
1276         goto out;
1277 }
1278
1279 static int
1280 cifs_push_locks(struct cifsFileInfo *cfile)
1281 {
1282         struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->dentry->d_sb);
1283         struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
1284         struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
1285         int rc = 0;
1286
1287         /* we are going to update can_cache_brlcks here - need a write access */
1288         down_write(&cinode->lock_sem);
1289         if (!cinode->can_cache_brlcks) {
1290                 up_write(&cinode->lock_sem);
1291                 return rc;
1292         }
1293
1294         if (cap_unix(tcon->ses) &&
1295             (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
1296             ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
1297                 rc = cifs_push_posix_locks(cfile);
1298         else
1299                 rc = tcon->ses->server->ops->push_mand_locks(cfile);
1300
1301         cinode->can_cache_brlcks = false;
1302         up_write(&cinode->lock_sem);
1303         return rc;
1304 }
1305
1306 static void
1307 cifs_read_flock(struct file_lock *flock, __u32 *type, int *lock, int *unlock,
1308                 bool *wait_flag, struct TCP_Server_Info *server)
1309 {
1310         if (flock->fl_flags & FL_POSIX)
1311                 cifs_dbg(FYI, "Posix\n");
1312         if (flock->fl_flags & FL_FLOCK)
1313                 cifs_dbg(FYI, "Flock\n");
1314         if (flock->fl_flags & FL_SLEEP) {
1315                 cifs_dbg(FYI, "Blocking lock\n");
1316                 *wait_flag = true;
1317         }
1318         if (flock->fl_flags & FL_ACCESS)
1319                 cifs_dbg(FYI, "Process suspended by mandatory locking - not implemented yet\n");
1320         if (flock->fl_flags & FL_LEASE)
1321                 cifs_dbg(FYI, "Lease on file - not implemented yet\n");
1322         if (flock->fl_flags &
1323             (~(FL_POSIX | FL_FLOCK | FL_SLEEP |
1324                FL_ACCESS | FL_LEASE | FL_CLOSE)))
1325                 cifs_dbg(FYI, "Unknown lock flags 0x%x\n", flock->fl_flags);
1326
1327         *type = server->vals->large_lock_type;
1328         if (flock->fl_type == F_WRLCK) {
1329                 cifs_dbg(FYI, "F_WRLCK\n");
1330                 *type |= server->vals->exclusive_lock_type;
1331                 *lock = 1;
1332         } else if (flock->fl_type == F_UNLCK) {
1333                 cifs_dbg(FYI, "F_UNLCK\n");
1334                 *type |= server->vals->unlock_lock_type;
1335                 *unlock = 1;
1336                 /* Check if unlock includes more than one lock range */
1337         } else if (flock->fl_type == F_RDLCK) {
1338                 cifs_dbg(FYI, "F_RDLCK\n");
1339                 *type |= server->vals->shared_lock_type;
1340                 *lock = 1;
1341         } else if (flock->fl_type == F_EXLCK) {
1342                 cifs_dbg(FYI, "F_EXLCK\n");
1343                 *type |= server->vals->exclusive_lock_type;
1344                 *lock = 1;
1345         } else if (flock->fl_type == F_SHLCK) {
1346                 cifs_dbg(FYI, "F_SHLCK\n");
1347                 *type |= server->vals->shared_lock_type;
1348                 *lock = 1;
1349         } else
1350                 cifs_dbg(FYI, "Unknown type of lock\n");
1351 }
1352
1353 static int
1354 cifs_getlk(struct file *file, struct file_lock *flock, __u32 type,
1355            bool wait_flag, bool posix_lck, unsigned int xid)
1356 {
1357         int rc = 0;
1358         __u64 length = 1 + flock->fl_end - flock->fl_start;
1359         struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
1360         struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
1361         struct TCP_Server_Info *server = tcon->ses->server;
1362         __u16 netfid = cfile->fid.netfid;
1363
1364         if (posix_lck) {
1365                 int posix_lock_type;
1366
1367                 rc = cifs_posix_lock_test(file, flock);
1368                 if (!rc)
1369                         return rc;
1370
1371                 if (type & server->vals->shared_lock_type)
1372                         posix_lock_type = CIFS_RDLCK;
1373                 else
1374                         posix_lock_type = CIFS_WRLCK;
1375                 rc = CIFSSMBPosixLock(xid, tcon, netfid,
1376                                       hash_lockowner(flock->fl_owner),
1377                                       flock->fl_start, length, flock,
1378                                       posix_lock_type, wait_flag);
1379                 return rc;
1380         }
1381
1382         rc = cifs_lock_test(cfile, flock->fl_start, length, type, flock);
1383         if (!rc)
1384                 return rc;
1385
1386         /* BB we could chain these into one lock request BB */
1387         rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length, type,
1388                                     1, 0, false);
1389         if (rc == 0) {
1390                 rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length,
1391                                             type, 0, 1, false);
1392                 flock->fl_type = F_UNLCK;
1393                 if (rc != 0)
1394                         cifs_dbg(VFS, "Error unlocking previously locked range %d during test of lock\n",
1395                                  rc);
1396                 return 0;
1397         }
1398
1399         if (type & server->vals->shared_lock_type) {
1400                 flock->fl_type = F_WRLCK;
1401                 return 0;
1402         }
1403
1404         type &= ~server->vals->exclusive_lock_type;
1405
1406         rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length,
1407                                     type | server->vals->shared_lock_type,
1408                                     1, 0, false);
1409         if (rc == 0) {
1410                 rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length,
1411                         type | server->vals->shared_lock_type, 0, 1, false);
1412                 flock->fl_type = F_RDLCK;
1413                 if (rc != 0)
1414                         cifs_dbg(VFS, "Error unlocking previously locked range %d during test of lock\n",
1415                                  rc);
1416         } else
1417                 flock->fl_type = F_WRLCK;
1418
1419         return 0;
1420 }
1421
1422 void
1423 cifs_move_llist(struct list_head *source, struct list_head *dest)
1424 {
1425         struct list_head *li, *tmp;
1426         list_for_each_safe(li, tmp, source)
1427                 list_move(li, dest);
1428 }
1429
1430 void
1431 cifs_free_llist(struct list_head *llist)
1432 {
1433         struct cifsLockInfo *li, *tmp;
1434         list_for_each_entry_safe(li, tmp, llist, llist) {
1435                 cifs_del_lock_waiters(li);
1436                 list_del(&li->llist);
1437                 kfree(li);
1438         }
1439 }
1440
1441 int
1442 cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
1443                   unsigned int xid)
1444 {
1445         int rc = 0, stored_rc;
1446         static const int types[] = {
1447                 LOCKING_ANDX_LARGE_FILES,
1448                 LOCKING_ANDX_SHARED_LOCK | LOCKING_ANDX_LARGE_FILES
1449         };
1450         unsigned int i;
1451         unsigned int max_num, num, max_buf;
1452         LOCKING_ANDX_RANGE *buf, *cur;
1453         struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
1454         struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
1455         struct cifsLockInfo *li, *tmp;
1456         __u64 length = 1 + flock->fl_end - flock->fl_start;
1457         struct list_head tmp_llist;
1458
1459         INIT_LIST_HEAD(&tmp_llist);
1460
1461         /*
1462          * Accessing maxBuf is racy with cifs_reconnect - need to store value
1463          * and check it for zero before using.
1464          */
1465         max_buf = tcon->ses->server->maxBuf;
1466         if (!max_buf)
1467                 return -EINVAL;
1468
1469         max_num = (max_buf - sizeof(struct smb_hdr)) /
1470                                                 sizeof(LOCKING_ANDX_RANGE);
1471         buf = kcalloc(max_num, sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
1472         if (!buf)
1473                 return -ENOMEM;
1474
1475         down_write(&cinode->lock_sem);
1476         for (i = 0; i < 2; i++) {
1477                 cur = buf;
1478                 num = 0;
1479                 list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
1480                         if (flock->fl_start > li->offset ||
1481                             (flock->fl_start + length) <
1482                             (li->offset + li->length))
1483                                 continue;
1484                         if (current->tgid != li->pid)
1485                                 continue;
1486                         if (types[i] != li->type)
1487                                 continue;
1488                         if (cinode->can_cache_brlcks) {
1489                                 /*
1490                                  * We can cache brlock requests - simply remove
1491                                  * a lock from the file's list.
1492                                  */
1493                                 list_del(&li->llist);
1494                                 cifs_del_lock_waiters(li);
1495                                 kfree(li);
1496                                 continue;
1497                         }
1498                         cur->Pid = cpu_to_le16(li->pid);
1499                         cur->LengthLow = cpu_to_le32((u32)li->length);
1500                         cur->LengthHigh = cpu_to_le32((u32)(li->length>>32));
1501                         cur->OffsetLow = cpu_to_le32((u32)li->offset);
1502                         cur->OffsetHigh = cpu_to_le32((u32)(li->offset>>32));
1503                         /*
1504                          * We need to save a lock here to let us add it again to
1505                          * the file's list if the unlock range request fails on
1506                          * the server.
1507                          */
1508                         list_move(&li->llist, &tmp_llist);
1509                         if (++num == max_num) {
1510                                 stored_rc = cifs_lockv(xid, tcon,
1511                                                        cfile->fid.netfid,
1512                                                        li->type, num, 0, buf);
1513                                 if (stored_rc) {
1514                                         /*
1515                                          * We failed on the unlock range
1516                                          * request - add all locks from the tmp
1517                                          * list to the head of the file's list.
1518                                          */
1519                                         cifs_move_llist(&tmp_llist,
1520                                                         &cfile->llist->locks);
1521                                         rc = stored_rc;
1522                                 } else
1523                                         /*
1524                                          * The unlock range request succeed -
1525                                          * free the tmp list.
1526                                          */
1527                                         cifs_free_llist(&tmp_llist);
1528                                 cur = buf;
1529                                 num = 0;
1530                         } else
1531                                 cur++;
1532                 }
1533                 if (num) {
1534                         stored_rc = cifs_lockv(xid, tcon, cfile->fid.netfid,
1535                                                types[i], num, 0, buf);
1536                         if (stored_rc) {
1537                                 cifs_move_llist(&tmp_llist,
1538                                                 &cfile->llist->locks);
1539                                 rc = stored_rc;
1540                         } else
1541                                 cifs_free_llist(&tmp_llist);
1542                 }
1543         }
1544
1545         up_write(&cinode->lock_sem);
1546         kfree(buf);
1547         return rc;
1548 }
1549
1550 static int
1551 cifs_setlk(struct file *file, struct file_lock *flock, __u32 type,
1552            bool wait_flag, bool posix_lck, int lock, int unlock,
1553            unsigned int xid)
1554 {
1555         int rc = 0;
1556         __u64 length = 1 + flock->fl_end - flock->fl_start;
1557         struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
1558         struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
1559         struct TCP_Server_Info *server = tcon->ses->server;
1560         struct inode *inode = d_inode(cfile->dentry);
1561
1562         if (posix_lck) {
1563                 int posix_lock_type;
1564
1565                 rc = cifs_posix_lock_set(file, flock);
1566                 if (!rc || rc < 0)
1567                         return rc;
1568
1569                 if (type & server->vals->shared_lock_type)
1570                         posix_lock_type = CIFS_RDLCK;
1571                 else
1572                         posix_lock_type = CIFS_WRLCK;
1573
1574                 if (unlock == 1)
1575                         posix_lock_type = CIFS_UNLCK;
1576
1577                 rc = CIFSSMBPosixLock(xid, tcon, cfile->fid.netfid,
1578                                       hash_lockowner(flock->fl_owner),
1579                                       flock->fl_start, length,
1580                                       NULL, posix_lock_type, wait_flag);
1581                 goto out;
1582         }
1583
1584         if (lock) {
1585                 struct cifsLockInfo *lock;
1586
1587                 lock = cifs_lock_init(flock->fl_start, length, type);
1588                 if (!lock)
1589                         return -ENOMEM;
1590
1591                 rc = cifs_lock_add_if(cfile, lock, wait_flag);
1592                 if (rc < 0) {
1593                         kfree(lock);
1594                         return rc;
1595                 }
1596                 if (!rc)
1597                         goto out;
1598
1599                 /*
1600                  * Windows 7 server can delay breaking lease from read to None
1601                  * if we set a byte-range lock on a file - break it explicitly
1602                  * before sending the lock to the server to be sure the next
1603                  * read won't conflict with non-overlapted locks due to
1604                  * pagereading.
1605                  */
1606                 if (!CIFS_CACHE_WRITE(CIFS_I(inode)) &&
1607                                         CIFS_CACHE_READ(CIFS_I(inode))) {
1608                         cifs_zap_mapping(inode);
1609                         cifs_dbg(FYI, "Set no oplock for inode=%p due to mand locks\n",
1610                                  inode);
1611                         CIFS_I(inode)->oplock = 0;
1612                 }
1613
1614                 rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length,
1615                                             type, 1, 0, wait_flag);
1616                 if (rc) {
1617                         kfree(lock);
1618                         return rc;
1619                 }
1620
1621                 cifs_lock_add(cfile, lock);
1622         } else if (unlock)
1623                 rc = server->ops->mand_unlock_range(cfile, flock, xid);
1624
1625 out:
1626         if (flock->fl_flags & FL_POSIX && !rc)
1627                 rc = locks_lock_file_wait(file, flock);
1628         return rc;
1629 }
1630
1631 int cifs_lock(struct file *file, int cmd, struct file_lock *flock)
1632 {
1633         int rc, xid;
1634         int lock = 0, unlock = 0;
1635         bool wait_flag = false;
1636         bool posix_lck = false;
1637         struct cifs_sb_info *cifs_sb;
1638         struct cifs_tcon *tcon;
1639         struct cifsInodeInfo *cinode;
1640         struct cifsFileInfo *cfile;
1641         __u16 netfid;
1642         __u32 type;
1643
1644         rc = -EACCES;
1645         xid = get_xid();
1646
1647         cifs_dbg(FYI, "Lock parm: 0x%x flockflags: 0x%x flocktype: 0x%x start: %lld end: %lld\n",
1648                  cmd, flock->fl_flags, flock->fl_type,
1649                  flock->fl_start, flock->fl_end);
1650
1651         cfile = (struct cifsFileInfo *)file->private_data;
1652         tcon = tlink_tcon(cfile->tlink);
1653
1654         cifs_read_flock(flock, &type, &lock, &unlock, &wait_flag,
1655                         tcon->ses->server);
1656
1657         cifs_sb = CIFS_FILE_SB(file);
1658         netfid = cfile->fid.netfid;
1659         cinode = CIFS_I(file_inode(file));
1660
1661         if (cap_unix(tcon->ses) &&
1662             (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
1663             ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
1664                 posix_lck = true;
1665         /*
1666          * BB add code here to normalize offset and length to account for
1667          * negative length which we can not accept over the wire.
1668          */
1669         if (IS_GETLK(cmd)) {
1670                 rc = cifs_getlk(file, flock, type, wait_flag, posix_lck, xid);
1671                 free_xid(xid);
1672                 return rc;
1673         }
1674
1675         if (!lock && !unlock) {
1676                 /*
1677                  * if no lock or unlock then nothing to do since we do not
1678                  * know what it is
1679                  */
1680                 free_xid(xid);
1681                 return -EOPNOTSUPP;
1682         }
1683
1684         rc = cifs_setlk(file, flock, type, wait_flag, posix_lck, lock, unlock,
1685                         xid);
1686         free_xid(xid);
1687         return rc;
1688 }
1689
1690 /*
1691  * update the file size (if needed) after a write. Should be called with
1692  * the inode->i_lock held
1693  */
1694 void
1695 cifs_update_eof(struct cifsInodeInfo *cifsi, loff_t offset,
1696                       unsigned int bytes_written)
1697 {
1698         loff_t end_of_write = offset + bytes_written;
1699
1700         if (end_of_write > cifsi->server_eof)
1701                 cifsi->server_eof = end_of_write;
1702 }
1703
1704 static ssize_t
1705 cifs_write(struct cifsFileInfo *open_file, __u32 pid, const char *write_data,
1706            size_t write_size, loff_t *offset)
1707 {
1708         int rc = 0;
1709         unsigned int bytes_written = 0;
1710         unsigned int total_written;
1711         struct cifs_sb_info *cifs_sb;
1712         struct cifs_tcon *tcon;
1713         struct TCP_Server_Info *server;
1714         unsigned int xid;
1715         struct dentry *dentry = open_file->dentry;
1716         struct cifsInodeInfo *cifsi = CIFS_I(d_inode(dentry));
1717         struct cifs_io_parms io_parms;
1718
1719         cifs_sb = CIFS_SB(dentry->d_sb);
1720
1721         cifs_dbg(FYI, "write %zd bytes to offset %lld of %pd\n",
1722                  write_size, *offset, dentry);
1723
1724         tcon = tlink_tcon(open_file->tlink);
1725         server = tcon->ses->server;
1726
1727         if (!server->ops->sync_write)
1728                 return -ENOSYS;
1729
1730         xid = get_xid();
1731
1732         for (total_written = 0; write_size > total_written;
1733              total_written += bytes_written) {
1734                 rc = -EAGAIN;
1735                 while (rc == -EAGAIN) {
1736                         struct kvec iov[2];
1737                         unsigned int len;
1738
1739                         if (open_file->invalidHandle) {
1740                                 /* we could deadlock if we called
1741                                    filemap_fdatawait from here so tell
1742                                    reopen_file not to flush data to
1743                                    server now */
1744                                 rc = cifs_reopen_file(open_file, false);
1745                                 if (rc != 0)
1746                                         break;
1747                         }
1748
1749                         len = min(server->ops->wp_retry_size(d_inode(dentry)),
1750                                   (unsigned int)write_size - total_written);
1751                         /* iov[0] is reserved for smb header */
1752                         iov[1].iov_base = (char *)write_data + total_written;
1753                         iov[1].iov_len = len;
1754                         io_parms.pid = pid;
1755                         io_parms.tcon = tcon;
1756                         io_parms.offset = *offset;
1757                         io_parms.length = len;
1758                         rc = server->ops->sync_write(xid, &open_file->fid,
1759                                         &io_parms, &bytes_written, iov, 1);
1760                 }
1761                 if (rc || (bytes_written == 0)) {
1762                         if (total_written)
1763                                 break;
1764                         else {
1765                                 free_xid(xid);
1766                                 return rc;
1767                         }
1768                 } else {
1769                         spin_lock(&d_inode(dentry)->i_lock);
1770                         cifs_update_eof(cifsi, *offset, bytes_written);
1771                         spin_unlock(&d_inode(dentry)->i_lock);
1772                         *offset += bytes_written;
1773                 }
1774         }
1775
1776         cifs_stats_bytes_written(tcon, total_written);
1777
1778         if (total_written > 0) {
1779                 spin_lock(&d_inode(dentry)->i_lock);
1780                 if (*offset > d_inode(dentry)->i_size)
1781                         i_size_write(d_inode(dentry), *offset);
1782                 spin_unlock(&d_inode(dentry)->i_lock);
1783         }
1784         mark_inode_dirty_sync(d_inode(dentry));
1785         free_xid(xid);
1786         return total_written;
1787 }
1788
1789 struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode,
1790                                         bool fsuid_only)
1791 {
1792         struct cifsFileInfo *open_file = NULL;
1793         struct cifs_sb_info *cifs_sb = CIFS_SB(cifs_inode->vfs_inode.i_sb);
1794         struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
1795
1796         /* only filter by fsuid on multiuser mounts */
1797         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
1798                 fsuid_only = false;
1799
1800         spin_lock(&tcon->open_file_lock);
1801         /* we could simply get the first_list_entry since write-only entries
1802            are always at the end of the list but since the first entry might
1803            have a close pending, we go through the whole list */
1804         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
1805                 if (fsuid_only && !uid_eq(open_file->uid, current_fsuid()))
1806                         continue;
1807                 if (OPEN_FMODE(open_file->f_flags) & FMODE_READ) {
1808                         if (!open_file->invalidHandle) {
1809                                 /* found a good file */
1810                                 /* lock it so it will not be closed on us */
1811                                 cifsFileInfo_get(open_file);
1812                                 spin_unlock(&tcon->open_file_lock);
1813                                 return open_file;
1814                         } /* else might as well continue, and look for
1815                              another, or simply have the caller reopen it
1816                              again rather than trying to fix this handle */
1817                 } else /* write only file */
1818                         break; /* write only files are last so must be done */
1819         }
1820         spin_unlock(&tcon->open_file_lock);
1821         return NULL;
1822 }
1823
1824 struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode,
1825                                         bool fsuid_only)
1826 {
1827         struct cifsFileInfo *open_file, *inv_file = NULL;
1828         struct cifs_sb_info *cifs_sb;
1829         struct cifs_tcon *tcon;
1830         bool any_available = false;
1831         int rc;
1832         unsigned int refind = 0;
1833
1834         /* Having a null inode here (because mapping->host was set to zero by
1835         the VFS or MM) should not happen but we had reports of on oops (due to
1836         it being zero) during stress testcases so we need to check for it */
1837
1838         if (cifs_inode == NULL) {
1839                 cifs_dbg(VFS, "Null inode passed to cifs_writeable_file\n");
1840                 dump_stack();
1841                 return NULL;
1842         }
1843
1844         cifs_sb = CIFS_SB(cifs_inode->vfs_inode.i_sb);
1845         tcon = cifs_sb_master_tcon(cifs_sb);
1846
1847         /* only filter by fsuid on multiuser mounts */
1848         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
1849                 fsuid_only = false;
1850
1851         spin_lock(&tcon->open_file_lock);
1852 refind_writable:
1853         if (refind > MAX_REOPEN_ATT) {
1854                 spin_unlock(&tcon->open_file_lock);
1855                 return NULL;
1856         }
1857         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
1858                 if (!any_available && open_file->pid != current->tgid)
1859                         continue;
1860                 if (fsuid_only && !uid_eq(open_file->uid, current_fsuid()))
1861                         continue;
1862                 if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
1863                         if (!open_file->invalidHandle) {
1864                                 /* found a good writable file */
1865                                 cifsFileInfo_get(open_file);
1866                                 spin_unlock(&tcon->open_file_lock);
1867                                 return open_file;
1868                         } else {
1869                                 if (!inv_file)
1870                                         inv_file = open_file;
1871                         }
1872                 }
1873         }
1874         /* couldn't find useable FH with same pid, try any available */
1875         if (!any_available) {
1876                 any_available = true;
1877                 goto refind_writable;
1878         }
1879
1880         if (inv_file) {
1881                 any_available = false;
1882                 cifsFileInfo_get(inv_file);
1883         }
1884
1885         spin_unlock(&tcon->open_file_lock);
1886
1887         if (inv_file) {
1888                 rc = cifs_reopen_file(inv_file, false);
1889                 if (!rc)
1890                         return inv_file;
1891                 else {
1892                         spin_lock(&tcon->open_file_lock);
1893                         list_move_tail(&inv_file->flist,
1894                                         &cifs_inode->openFileList);
1895                         spin_unlock(&tcon->open_file_lock);
1896                         cifsFileInfo_put(inv_file);
1897                         ++refind;
1898                         inv_file = NULL;
1899                         spin_lock(&tcon->open_file_lock);
1900                         goto refind_writable;
1901                 }
1902         }
1903
1904         return NULL;
1905 }
1906
1907 static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
1908 {
1909         struct address_space *mapping = page->mapping;
1910         loff_t offset = (loff_t)page->index << PAGE_SHIFT;
1911         char *write_data;
1912         int rc = -EFAULT;
1913         int bytes_written = 0;
1914         struct inode *inode;
1915         struct cifsFileInfo *open_file;
1916
1917         if (!mapping || !mapping->host)
1918                 return -EFAULT;
1919
1920         inode = page->mapping->host;
1921
1922         offset += (loff_t)from;
1923         write_data = kmap(page);
1924         write_data += from;
1925
1926         if ((to > PAGE_SIZE) || (from > to)) {
1927                 kunmap(page);
1928                 return -EIO;
1929         }
1930
1931         /* racing with truncate? */
1932         if (offset > mapping->host->i_size) {
1933                 kunmap(page);
1934                 return 0; /* don't care */
1935         }
1936
1937         /* check to make sure that we are not extending the file */
1938         if (mapping->host->i_size - offset < (loff_t)to)
1939                 to = (unsigned)(mapping->host->i_size - offset);
1940
1941         open_file = find_writable_file(CIFS_I(mapping->host), false);
1942         if (open_file) {
1943                 bytes_written = cifs_write(open_file, open_file->pid,
1944                                            write_data, to - from, &offset);
1945                 cifsFileInfo_put(open_file);
1946                 /* Does mm or vfs already set times? */
1947                 inode->i_atime = inode->i_mtime = current_time(inode);
1948                 if ((bytes_written > 0) && (offset))
1949                         rc = 0;
1950                 else if (bytes_written < 0)
1951                         rc = bytes_written;
1952         } else {
1953                 cifs_dbg(FYI, "No writeable filehandles for inode\n");
1954                 rc = -EIO;
1955         }
1956
1957         kunmap(page);
1958         return rc;
1959 }
1960
1961 static struct cifs_writedata *
1962 wdata_alloc_and_fillpages(pgoff_t tofind, struct address_space *mapping,
1963                           pgoff_t end, pgoff_t *index,
1964                           unsigned int *found_pages)
1965 {
1966         struct cifs_writedata *wdata;
1967
1968         wdata = cifs_writedata_alloc((unsigned int)tofind,
1969                                      cifs_writev_complete);
1970         if (!wdata)
1971                 return NULL;
1972
1973         *found_pages = find_get_pages_range_tag(mapping, index, end,
1974                                 PAGECACHE_TAG_DIRTY, tofind, wdata->pages);
1975         return wdata;
1976 }
1977
1978 static unsigned int
1979 wdata_prepare_pages(struct cifs_writedata *wdata, unsigned int found_pages,
1980                     struct address_space *mapping,
1981                     struct writeback_control *wbc,
1982                     pgoff_t end, pgoff_t *index, pgoff_t *next, bool *done)
1983 {
1984         unsigned int nr_pages = 0, i;
1985         struct page *page;
1986
1987         for (i = 0; i < found_pages; i++) {
1988                 page = wdata->pages[i];
1989                 /*
1990                  * At this point we hold neither mapping->tree_lock nor
1991                  * lock on the page itself: the page may be truncated or
1992                  * invalidated (changing page->mapping to NULL), or even
1993                  * swizzled back from swapper_space to tmpfs file
1994                  * mapping
1995                  */
1996
1997                 if (nr_pages == 0)
1998                         lock_page(page);
1999                 else if (!trylock_page(page))
2000                         break;
2001
2002                 if (unlikely(page->mapping != mapping)) {
2003                         unlock_page(page);
2004                         break;
2005                 }
2006
2007                 if (!wbc->range_cyclic && page->index > end) {
2008                         *done = true;
2009                         unlock_page(page);
2010                         break;
2011                 }
2012
2013                 if (*next && (page->index != *next)) {
2014                         /* Not next consecutive page */
2015                         unlock_page(page);
2016                         break;
2017                 }
2018
2019                 if (wbc->sync_mode != WB_SYNC_NONE)
2020                         wait_on_page_writeback(page);
2021
2022                 if (PageWriteback(page) ||
2023                                 !clear_page_dirty_for_io(page)) {
2024                         unlock_page(page);
2025                         break;
2026                 }
2027
2028                 /*
2029                  * This actually clears the dirty bit in the radix tree.
2030                  * See cifs_writepage() for more commentary.
2031                  */
2032                 set_page_writeback(page);
2033                 if (page_offset(page) >= i_size_read(mapping->host)) {
2034                         *done = true;
2035                         unlock_page(page);
2036                         end_page_writeback(page);
2037                         break;
2038                 }
2039
2040                 wdata->pages[i] = page;
2041                 *next = page->index + 1;
2042                 ++nr_pages;
2043         }
2044
2045         /* reset index to refind any pages skipped */
2046         if (nr_pages == 0)
2047                 *index = wdata->pages[0]->index + 1;
2048
2049         /* put any pages we aren't going to use */
2050         for (i = nr_pages; i < found_pages; i++) {
2051                 put_page(wdata->pages[i]);
2052                 wdata->pages[i] = NULL;
2053         }
2054
2055         return nr_pages;
2056 }
2057
2058 static int
2059 wdata_send_pages(struct cifs_writedata *wdata, unsigned int nr_pages,
2060                  struct address_space *mapping, struct writeback_control *wbc)
2061 {
2062         int rc = 0;
2063         struct TCP_Server_Info *server;
2064         unsigned int i;
2065
2066         wdata->sync_mode = wbc->sync_mode;
2067         wdata->nr_pages = nr_pages;
2068         wdata->offset = page_offset(wdata->pages[0]);
2069         wdata->pagesz = PAGE_SIZE;
2070         wdata->tailsz = min(i_size_read(mapping->host) -
2071                         page_offset(wdata->pages[nr_pages - 1]),
2072                         (loff_t)PAGE_SIZE);
2073         wdata->bytes = ((nr_pages - 1) * PAGE_SIZE) + wdata->tailsz;
2074
2075         if (wdata->cfile != NULL)
2076                 cifsFileInfo_put(wdata->cfile);
2077         wdata->cfile = find_writable_file(CIFS_I(mapping->host), false);
2078         if (!wdata->cfile) {
2079                 cifs_dbg(VFS, "No writable handles for inode\n");
2080                 rc = -EBADF;
2081         } else {
2082                 wdata->pid = wdata->cfile->pid;
2083                 server = tlink_tcon(wdata->cfile->tlink)->ses->server;
2084                 rc = server->ops->async_writev(wdata, cifs_writedata_release);
2085         }
2086
2087         for (i = 0; i < nr_pages; ++i)
2088                 unlock_page(wdata->pages[i]);
2089
2090         return rc;
2091 }
2092
2093 static int cifs_writepages(struct address_space *mapping,
2094                            struct writeback_control *wbc)
2095 {
2096         struct cifs_sb_info *cifs_sb = CIFS_SB(mapping->host->i_sb);
2097         struct TCP_Server_Info *server;
2098         bool done = false, scanned = false, range_whole = false;
2099         pgoff_t end, index;
2100         struct cifs_writedata *wdata;
2101         int rc = 0;
2102
2103         /*
2104          * If wsize is smaller than the page cache size, default to writing
2105          * one page at a time via cifs_writepage
2106          */
2107         if (cifs_sb->wsize < PAGE_SIZE)
2108                 return generic_writepages(mapping, wbc);
2109
2110         if (wbc->range_cyclic) {
2111                 index = mapping->writeback_index; /* Start from prev offset */
2112                 end = -1;
2113         } else {
2114                 index = wbc->range_start >> PAGE_SHIFT;
2115                 end = wbc->range_end >> PAGE_SHIFT;
2116                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2117                         range_whole = true;
2118                 scanned = true;
2119         }
2120         server = cifs_sb_master_tcon(cifs_sb)->ses->server;
2121 retry:
2122         while (!done && index <= end) {
2123                 unsigned int i, nr_pages, found_pages, wsize, credits;
2124                 pgoff_t next = 0, tofind, saved_index = index;
2125
2126                 rc = server->ops->wait_mtu_credits(server, cifs_sb->wsize,
2127                                                    &wsize, &credits);
2128                 if (rc)
2129                         break;
2130
2131                 tofind = min((wsize / PAGE_SIZE) - 1, end - index) + 1;
2132
2133                 wdata = wdata_alloc_and_fillpages(tofind, mapping, end, &index,
2134                                                   &found_pages);
2135                 if (!wdata) {
2136                         rc = -ENOMEM;
2137                         add_credits_and_wake_if(server, credits, 0);
2138                         break;
2139                 }
2140
2141                 if (found_pages == 0) {
2142                         kref_put(&wdata->refcount, cifs_writedata_release);
2143                         add_credits_and_wake_if(server, credits, 0);
2144                         break;
2145                 }
2146
2147                 nr_pages = wdata_prepare_pages(wdata, found_pages, mapping, wbc,
2148                                                end, &index, &next, &done);
2149
2150                 /* nothing to write? */
2151                 if (nr_pages == 0) {
2152                         kref_put(&wdata->refcount, cifs_writedata_release);
2153                         add_credits_and_wake_if(server, credits, 0);
2154                         continue;
2155                 }
2156
2157                 wdata->credits = credits;
2158
2159                 rc = wdata_send_pages(wdata, nr_pages, mapping, wbc);
2160
2161                 /* send failure -- clean up the mess */
2162                 if (rc != 0) {
2163                         add_credits_and_wake_if(server, wdata->credits, 0);
2164                         for (i = 0; i < nr_pages; ++i) {
2165                                 if (rc == -EAGAIN)
2166                                         redirty_page_for_writepage(wbc,
2167                                                            wdata->pages[i]);
2168                                 else
2169                                         SetPageError(wdata->pages[i]);
2170                                 end_page_writeback(wdata->pages[i]);
2171                                 put_page(wdata->pages[i]);
2172                         }
2173                         if (rc != -EAGAIN)
2174                                 mapping_set_error(mapping, rc);
2175                 }
2176                 kref_put(&wdata->refcount, cifs_writedata_release);
2177
2178                 if (wbc->sync_mode == WB_SYNC_ALL && rc == -EAGAIN) {
2179                         index = saved_index;
2180                         continue;
2181                 }
2182
2183                 wbc->nr_to_write -= nr_pages;
2184                 if (wbc->nr_to_write <= 0)
2185                         done = true;
2186
2187                 index = next;
2188         }
2189
2190         if (!scanned && !done) {
2191                 /*
2192                  * We hit the last page and there is more work to be done: wrap
2193                  * back to the start of the file
2194                  */
2195                 scanned = true;
2196                 index = 0;
2197                 goto retry;
2198         }
2199
2200         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2201                 mapping->writeback_index = index;
2202
2203         return rc;
2204 }
2205
2206 static int
2207 cifs_writepage_locked(struct page *page, struct writeback_control *wbc)
2208 {
2209         int rc;
2210         unsigned int xid;
2211
2212         xid = get_xid();
2213 /* BB add check for wbc flags */
2214         get_page(page);
2215         if (!PageUptodate(page))
2216                 cifs_dbg(FYI, "ppw - page not up to date\n");
2217
2218         /*
2219          * Set the "writeback" flag, and clear "dirty" in the radix tree.
2220          *
2221          * A writepage() implementation always needs to do either this,
2222          * or re-dirty the page with "redirty_page_for_writepage()" in
2223          * the case of a failure.
2224          *
2225          * Just unlocking the page will cause the radix tree tag-bits
2226          * to fail to update with the state of the page correctly.
2227          */
2228         set_page_writeback(page);
2229 retry_write:
2230         rc = cifs_partialpagewrite(page, 0, PAGE_SIZE);
2231         if (rc == -EAGAIN) {
2232                 if (wbc->sync_mode == WB_SYNC_ALL)
2233                         goto retry_write;
2234                 redirty_page_for_writepage(wbc, page);
2235         } else if (rc != 0) {
2236                 SetPageError(page);
2237                 mapping_set_error(page->mapping, rc);
2238         } else {
2239                 SetPageUptodate(page);
2240         }
2241         end_page_writeback(page);
2242         put_page(page);
2243         free_xid(xid);
2244         return rc;
2245 }
2246
2247 static int cifs_writepage(struct page *page, struct writeback_control *wbc)
2248 {
2249         int rc = cifs_writepage_locked(page, wbc);
2250         unlock_page(page);
2251         return rc;
2252 }
2253
2254 static int cifs_write_end(struct file *file, struct address_space *mapping,
2255                         loff_t pos, unsigned len, unsigned copied,
2256                         struct page *page, void *fsdata)
2257 {
2258         int rc;
2259         struct inode *inode = mapping->host;
2260         struct cifsFileInfo *cfile = file->private_data;
2261         struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->dentry->d_sb);
2262         __u32 pid;
2263
2264         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
2265                 pid = cfile->pid;
2266         else
2267                 pid = current->tgid;
2268
2269         cifs_dbg(FYI, "write_end for page %p from pos %lld with %d bytes\n",
2270                  page, pos, copied);
2271
2272         if (PageChecked(page)) {
2273                 if (copied == len)
2274                         SetPageUptodate(page);
2275                 ClearPageChecked(page);
2276         } else if (!PageUptodate(page) && copied == PAGE_SIZE)
2277                 SetPageUptodate(page);
2278
2279         if (!PageUptodate(page)) {
2280                 char *page_data;
2281                 unsigned offset = pos & (PAGE_SIZE - 1);
2282                 unsigned int xid;
2283
2284                 xid = get_xid();
2285                 /* this is probably better than directly calling
2286                    partialpage_write since in this function the file handle is
2287                    known which we might as well leverage */
2288                 /* BB check if anything else missing out of ppw
2289                    such as updating last write time */
2290                 page_data = kmap(page);
2291                 rc = cifs_write(cfile, pid, page_data + offset, copied, &pos);
2292                 /* if (rc < 0) should we set writebehind rc? */
2293                 kunmap(page);
2294
2295                 free_xid(xid);
2296         } else {
2297                 rc = copied;
2298                 pos += copied;
2299                 set_page_dirty(page);
2300         }
2301
2302         if (rc > 0) {
2303                 spin_lock(&inode->i_lock);
2304                 if (pos > inode->i_size)
2305                         i_size_write(inode, pos);
2306                 spin_unlock(&inode->i_lock);
2307         }
2308
2309         unlock_page(page);
2310         put_page(page);
2311
2312         return rc;
2313 }
2314
2315 int cifs_strict_fsync(struct file *file, loff_t start, loff_t end,
2316                       int datasync)
2317 {
2318         unsigned int xid;
2319         int rc = 0;
2320         struct cifs_tcon *tcon;
2321         struct TCP_Server_Info *server;
2322         struct cifsFileInfo *smbfile = file->private_data;
2323         struct inode *inode = file_inode(file);
2324         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
2325
2326         rc = file_write_and_wait_range(file, start, end);
2327         if (rc)
2328                 return rc;
2329         inode_lock(inode);
2330
2331         xid = get_xid();
2332
2333         cifs_dbg(FYI, "Sync file - name: %pD datasync: 0x%x\n",
2334                  file, datasync);
2335
2336         if (!CIFS_CACHE_READ(CIFS_I(inode))) {
2337                 rc = cifs_zap_mapping(inode);
2338                 if (rc) {
2339                         cifs_dbg(FYI, "rc: %d during invalidate phase\n", rc);
2340                         rc = 0; /* don't care about it in fsync */
2341                 }
2342         }
2343
2344         tcon = tlink_tcon(smbfile->tlink);
2345         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC)) {
2346                 server = tcon->ses->server;
2347                 if (server->ops->flush)
2348                         rc = server->ops->flush(xid, tcon, &smbfile->fid);
2349                 else
2350                         rc = -ENOSYS;
2351         }
2352
2353         free_xid(xid);
2354         inode_unlock(inode);
2355         return rc;
2356 }
2357
2358 int cifs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
2359 {
2360         unsigned int xid;
2361         int rc = 0;
2362         struct cifs_tcon *tcon;
2363         struct TCP_Server_Info *server;
2364         struct cifsFileInfo *smbfile = file->private_data;
2365         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
2366         struct inode *inode = file->f_mapping->host;
2367
2368         rc = file_write_and_wait_range(file, start, end);
2369         if (rc)
2370                 return rc;
2371         inode_lock(inode);
2372
2373         xid = get_xid();
2374
2375         cifs_dbg(FYI, "Sync file - name: %pD datasync: 0x%x\n",
2376                  file, datasync);
2377
2378         tcon = tlink_tcon(smbfile->tlink);
2379         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC)) {
2380                 server = tcon->ses->server;
2381                 if (server->ops->flush)
2382                         rc = server->ops->flush(xid, tcon, &smbfile->fid);
2383                 else
2384                         rc = -ENOSYS;
2385         }
2386
2387         free_xid(xid);
2388         inode_unlock(inode);
2389         return rc;
2390 }
2391
2392 /*
2393  * As file closes, flush all cached write data for this inode checking
2394  * for write behind errors.
2395  */
2396 int cifs_flush(struct file *file, fl_owner_t id)
2397 {
2398         struct inode *inode = file_inode(file);
2399         int rc = 0;
2400
2401         if (file->f_mode & FMODE_WRITE)
2402                 rc = filemap_write_and_wait(inode->i_mapping);
2403
2404         cifs_dbg(FYI, "Flush inode %p file %p rc %d\n", inode, file, rc);
2405
2406         return rc;
2407 }
2408
2409 static int
2410 cifs_write_allocate_pages(struct page **pages, unsigned long num_pages)
2411 {
2412         int rc = 0;
2413         unsigned long i;
2414
2415         for (i = 0; i < num_pages; i++) {
2416                 pages[i] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
2417                 if (!pages[i]) {
2418                         /*
2419                          * save number of pages we have already allocated and
2420                          * return with ENOMEM error
2421                          */
2422                         num_pages = i;
2423                         rc = -ENOMEM;
2424                         break;
2425                 }
2426         }
2427
2428         if (rc) {
2429                 for (i = 0; i < num_pages; i++)
2430                         put_page(pages[i]);
2431         }
2432         return rc;
2433 }
2434
2435 static inline
2436 size_t get_numpages(const size_t wsize, const size_t len, size_t *cur_len)
2437 {
2438         size_t num_pages;
2439         size_t clen;
2440
2441         clen = min_t(const size_t, len, wsize);
2442         num_pages = DIV_ROUND_UP(clen, PAGE_SIZE);
2443
2444         if (cur_len)
2445                 *cur_len = clen;
2446
2447         return num_pages;
2448 }
2449
2450 static void
2451 cifs_uncached_writedata_release(struct kref *refcount)
2452 {
2453         int i;
2454         struct cifs_writedata *wdata = container_of(refcount,
2455                                         struct cifs_writedata, refcount);
2456
2457         kref_put(&wdata->ctx->refcount, cifs_aio_ctx_release);
2458         for (i = 0; i < wdata->nr_pages; i++)
2459                 put_page(wdata->pages[i]);
2460         cifs_writedata_release(refcount);
2461 }
2462
2463 static void collect_uncached_write_data(struct cifs_aio_ctx *ctx);
2464
2465 static void
2466 cifs_uncached_writev_complete(struct work_struct *work)
2467 {
2468         struct cifs_writedata *wdata = container_of(work,
2469                                         struct cifs_writedata, work);
2470         struct inode *inode = d_inode(wdata->cfile->dentry);
2471         struct cifsInodeInfo *cifsi = CIFS_I(inode);
2472
2473         spin_lock(&inode->i_lock);
2474         cifs_update_eof(cifsi, wdata->offset, wdata->bytes);
2475         if (cifsi->server_eof > inode->i_size)
2476                 i_size_write(inode, cifsi->server_eof);
2477         spin_unlock(&inode->i_lock);
2478
2479         complete(&wdata->done);
2480         collect_uncached_write_data(wdata->ctx);
2481         /* the below call can possibly free the last ref to aio ctx */
2482         kref_put(&wdata->refcount, cifs_uncached_writedata_release);
2483 }
2484
2485 static int
2486 wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from,
2487                       size_t *len, unsigned long *num_pages)
2488 {
2489         size_t save_len, copied, bytes, cur_len = *len;
2490         unsigned long i, nr_pages = *num_pages;
2491
2492         save_len = cur_len;
2493         for (i = 0; i < nr_pages; i++) {
2494                 bytes = min_t(const size_t, cur_len, PAGE_SIZE);
2495                 copied = copy_page_from_iter(wdata->pages[i], 0, bytes, from);
2496                 cur_len -= copied;
2497                 /*
2498                  * If we didn't copy as much as we expected, then that
2499                  * may mean we trod into an unmapped area. Stop copying
2500                  * at that point. On the next pass through the big
2501                  * loop, we'll likely end up getting a zero-length
2502                  * write and bailing out of it.
2503                  */
2504                 if (copied < bytes)
2505                         break;
2506         }
2507         cur_len = save_len - cur_len;
2508         *len = cur_len;
2509
2510         /*
2511          * If we have no data to send, then that probably means that
2512          * the copy above failed altogether. That's most likely because
2513          * the address in the iovec was bogus. Return -EFAULT and let
2514          * the caller free anything we allocated and bail out.
2515          */
2516         if (!cur_len)
2517                 return -EFAULT;
2518
2519         /*
2520          * i + 1 now represents the number of pages we actually used in
2521          * the copy phase above.
2522          */
2523         *num_pages = i + 1;
2524         return 0;
2525 }
2526
2527 static int
2528 cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
2529                      struct cifsFileInfo *open_file,
2530                      struct cifs_sb_info *cifs_sb, struct list_head *wdata_list,
2531                      struct cifs_aio_ctx *ctx)
2532 {
2533         int rc = 0;
2534         size_t cur_len;
2535         unsigned long nr_pages, num_pages, i;
2536         struct cifs_writedata *wdata;
2537         struct iov_iter saved_from = *from;
2538         loff_t saved_offset = offset;
2539         pid_t pid;
2540         struct TCP_Server_Info *server;
2541
2542         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
2543                 pid = open_file->pid;
2544         else
2545                 pid = current->tgid;
2546
2547         server = tlink_tcon(open_file->tlink)->ses->server;
2548
2549         do {
2550                 unsigned int wsize, credits;
2551
2552                 rc = server->ops->wait_mtu_credits(server, cifs_sb->wsize,
2553                                                    &wsize, &credits);
2554                 if (rc)
2555                         break;
2556
2557                 nr_pages = get_numpages(wsize, len, &cur_len);
2558                 wdata = cifs_writedata_alloc(nr_pages,
2559                                              cifs_uncached_writev_complete);
2560                 if (!wdata) {
2561                         rc = -ENOMEM;
2562                         add_credits_and_wake_if(server, credits, 0);
2563                         break;
2564                 }
2565
2566                 rc = cifs_write_allocate_pages(wdata->pages, nr_pages);
2567                 if (rc) {
2568                         kfree(wdata);
2569                         add_credits_and_wake_if(server, credits, 0);
2570                         break;
2571                 }
2572
2573                 num_pages = nr_pages;
2574                 rc = wdata_fill_from_iovec(wdata, from, &cur_len, &num_pages);
2575                 if (rc) {
2576                         for (i = 0; i < nr_pages; i++)
2577                                 put_page(wdata->pages[i]);
2578                         kfree(wdata);
2579                         add_credits_and_wake_if(server, credits, 0);
2580                         break;
2581                 }
2582
2583                 /*
2584                  * Bring nr_pages down to the number of pages we actually used,
2585                  * and free any pages that we didn't use.
2586                  */
2587                 for ( ; nr_pages > num_pages; nr_pages--)
2588                         put_page(wdata->pages[nr_pages - 1]);
2589
2590                 wdata->sync_mode = WB_SYNC_ALL;
2591                 wdata->nr_pages = nr_pages;
2592                 wdata->offset = (__u64)offset;
2593                 wdata->cfile = cifsFileInfo_get(open_file);
2594                 wdata->pid = pid;
2595                 wdata->bytes = cur_len;
2596                 wdata->pagesz = PAGE_SIZE;
2597                 wdata->tailsz = cur_len - ((nr_pages - 1) * PAGE_SIZE);
2598                 wdata->credits = credits;
2599                 wdata->ctx = ctx;
2600                 kref_get(&ctx->refcount);
2601
2602                 if (!wdata->cfile->invalidHandle ||
2603                     !(rc = cifs_reopen_file(wdata->cfile, false)))
2604                         rc = server->ops->async_writev(wdata,
2605                                         cifs_uncached_writedata_release);
2606                 if (rc) {
2607                         add_credits_and_wake_if(server, wdata->credits, 0);
2608                         kref_put(&wdata->refcount,
2609                                  cifs_uncached_writedata_release);
2610                         if (rc == -EAGAIN) {
2611                                 *from = saved_from;
2612                                 iov_iter_advance(from, offset - saved_offset);
2613                                 continue;
2614                         }
2615                         break;
2616                 }
2617
2618                 list_add_tail(&wdata->list, wdata_list);
2619                 offset += cur_len;
2620                 len -= cur_len;
2621         } while (len > 0);
2622
2623         return rc;
2624 }
2625
2626 static void collect_uncached_write_data(struct cifs_aio_ctx *ctx)
2627 {
2628         struct cifs_writedata *wdata, *tmp;
2629         struct cifs_tcon *tcon;
2630         struct cifs_sb_info *cifs_sb;
2631         struct dentry *dentry = ctx->cfile->dentry;
2632         unsigned int i;
2633         int rc;
2634
2635         tcon = tlink_tcon(ctx->cfile->tlink);
2636         cifs_sb = CIFS_SB(dentry->d_sb);
2637
2638         mutex_lock(&ctx->aio_mutex);
2639
2640         if (list_empty(&ctx->list)) {
2641                 mutex_unlock(&ctx->aio_mutex);
2642                 return;
2643         }
2644
2645         rc = ctx->rc;
2646         /*
2647          * Wait for and collect replies for any successful sends in order of
2648          * increasing offset. Once an error is hit, then return without waiting
2649          * for any more replies.
2650          */
2651 restart_loop:
2652         list_for_each_entry_safe(wdata, tmp, &ctx->list, list) {
2653                 if (!rc) {
2654                         if (!try_wait_for_completion(&wdata->done)) {
2655                                 mutex_unlock(&ctx->aio_mutex);
2656                                 return;
2657                         }
2658
2659                         if (wdata->result)
2660                                 rc = wdata->result;
2661                         else
2662                                 ctx->total_len += wdata->bytes;
2663
2664                         /* resend call if it's a retryable error */
2665                         if (rc == -EAGAIN) {
2666                                 struct list_head tmp_list;
2667                                 struct iov_iter tmp_from = ctx->iter;
2668
2669                                 INIT_LIST_HEAD(&tmp_list);
2670                                 list_del_init(&wdata->list);
2671
2672                                 iov_iter_advance(&tmp_from,
2673                                                  wdata->offset - ctx->pos);
2674
2675                                 rc = cifs_write_from_iter(wdata->offset,
2676                                                 wdata->bytes, &tmp_from,
2677                                                 ctx->cfile, cifs_sb, &tmp_list,
2678                                                 ctx);
2679
2680                                 list_splice(&tmp_list, &ctx->list);
2681
2682                                 kref_put(&wdata->refcount,
2683                                          cifs_uncached_writedata_release);
2684                                 goto restart_loop;
2685                         }
2686                 }
2687                 list_del_init(&wdata->list);
2688                 kref_put(&wdata->refcount, cifs_uncached_writedata_release);
2689         }
2690
2691         for (i = 0; i < ctx->npages; i++)
2692                 put_page(ctx->bv[i].bv_page);
2693
2694         cifs_stats_bytes_written(tcon, ctx->total_len);
2695         set_bit(CIFS_INO_INVALID_MAPPING, &CIFS_I(dentry->d_inode)->flags);
2696
2697         ctx->rc = (rc == 0) ? ctx->total_len : rc;
2698
2699         mutex_unlock(&ctx->aio_mutex);
2700
2701         if (ctx->iocb && ctx->iocb->ki_complete)
2702                 ctx->iocb->ki_complete(ctx->iocb, ctx->rc, 0);
2703         else
2704                 complete(&ctx->done);
2705 }
2706
2707 ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
2708 {
2709         struct file *file = iocb->ki_filp;
2710         ssize_t total_written = 0;
2711         struct cifsFileInfo *cfile;
2712         struct cifs_tcon *tcon;
2713         struct cifs_sb_info *cifs_sb;
2714         struct cifs_aio_ctx *ctx;
2715         struct iov_iter saved_from = *from;
2716         int rc;
2717
2718         /*
2719          * BB - optimize the way when signing is disabled. We can drop this
2720          * extra memory-to-memory copying and use iovec buffers for constructing
2721          * write request.
2722          */
2723
2724         rc = generic_write_checks(iocb, from);
2725         if (rc <= 0)
2726                 return rc;
2727
2728         cifs_sb = CIFS_FILE_SB(file);
2729         cfile = file->private_data;
2730         tcon = tlink_tcon(cfile->tlink);
2731
2732         if (!tcon->ses->server->ops->async_writev)
2733                 return -ENOSYS;
2734
2735         ctx = cifs_aio_ctx_alloc();
2736         if (!ctx)
2737                 return -ENOMEM;
2738
2739         ctx->cfile = cifsFileInfo_get(cfile);
2740
2741         if (!is_sync_kiocb(iocb))
2742                 ctx->iocb = iocb;
2743
2744         ctx->pos = iocb->ki_pos;
2745
2746         rc = setup_aio_ctx_iter(ctx, from, WRITE);
2747         if (rc) {
2748                 kref_put(&ctx->refcount, cifs_aio_ctx_release);
2749                 return rc;
2750         }
2751
2752         /* grab a lock here due to read response handlers can access ctx */
2753         mutex_lock(&ctx->aio_mutex);
2754
2755         rc = cifs_write_from_iter(iocb->ki_pos, ctx->len, &saved_from,
2756                                   cfile, cifs_sb, &ctx->list, ctx);
2757
2758         /*
2759          * If at least one write was successfully sent, then discard any rc
2760          * value from the later writes. If the other write succeeds, then
2761          * we'll end up returning whatever was written. If it fails, then
2762          * we'll get a new rc value from that.
2763          */
2764         if (!list_empty(&ctx->list))
2765                 rc = 0;
2766
2767         mutex_unlock(&ctx->aio_mutex);
2768
2769         if (rc) {
2770                 kref_put(&ctx->refcount, cifs_aio_ctx_release);
2771                 return rc;
2772         }
2773
2774         if (!is_sync_kiocb(iocb)) {
2775                 kref_put(&ctx->refcount, cifs_aio_ctx_release);
2776                 return -EIOCBQUEUED;
2777         }
2778
2779         rc = wait_for_completion_killable(&ctx->done);
2780         if (rc) {
2781                 mutex_lock(&ctx->aio_mutex);
2782                 ctx->rc = rc = -EINTR;
2783                 total_written = ctx->total_len;
2784                 mutex_unlock(&ctx->aio_mutex);
2785         } else {
2786                 rc = ctx->rc;
2787                 total_written = ctx->total_len;
2788         }
2789
2790         kref_put(&ctx->refcount, cifs_aio_ctx_release);
2791
2792         if (unlikely(!total_written))
2793                 return rc;
2794
2795         iocb->ki_pos += total_written;
2796         return total_written;
2797 }
2798
2799 static ssize_t
2800 cifs_writev(struct kiocb *iocb, struct iov_iter *from)
2801 {
2802         struct file *file = iocb->ki_filp;
2803         struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
2804         struct inode *inode = file->f_mapping->host;
2805         struct cifsInodeInfo *cinode = CIFS_I(inode);
2806         struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
2807         ssize_t rc;
2808
2809         inode_lock(inode);
2810         /*
2811          * We need to hold the sem to be sure nobody modifies lock list
2812          * with a brlock that prevents writing.
2813          */
2814         down_read(&cinode->lock_sem);
2815
2816         rc = generic_write_checks(iocb, from);
2817         if (rc <= 0)
2818                 goto out;
2819
2820         if (!cifs_find_lock_conflict(cfile, iocb->ki_pos, iov_iter_count(from),
2821                                      server->vals->exclusive_lock_type, NULL,
2822                                      CIFS_WRITE_OP))
2823                 rc = __generic_file_write_iter(iocb, from);
2824         else
2825                 rc = -EACCES;
2826 out:
2827         up_read(&cinode->lock_sem);
2828         inode_unlock(inode);
2829
2830         if (rc > 0)
2831                 rc = generic_write_sync(iocb, rc);
2832         return rc;
2833 }
2834
2835 ssize_t
2836 cifs_strict_writev(struct kiocb *iocb, struct iov_iter *from)
2837 {
2838         struct inode *inode = file_inode(iocb->ki_filp);
2839         struct cifsInodeInfo *cinode = CIFS_I(inode);
2840         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
2841         struct cifsFileInfo *cfile = (struct cifsFileInfo *)
2842                                                 iocb->ki_filp->private_data;
2843         struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
2844         ssize_t written;
2845
2846         written = cifs_get_writer(cinode);
2847         if (written)
2848                 return written;
2849
2850         if (CIFS_CACHE_WRITE(cinode)) {
2851                 if (cap_unix(tcon->ses) &&
2852                 (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability))
2853                   && ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0)) {
2854                         written = generic_file_write_iter(iocb, from);
2855                         goto out;
2856                 }
2857                 written = cifs_writev(iocb, from);
2858                 goto out;
2859         }
2860         /*
2861          * For non-oplocked files in strict cache mode we need to write the data
2862          * to the server exactly from the pos to pos+len-1 rather than flush all
2863          * affected pages because it may cause a error with mandatory locks on
2864          * these pages but not on the region from pos to ppos+len-1.
2865          */
2866         written = cifs_user_writev(iocb, from);
2867         if (written > 0 && CIFS_CACHE_READ(cinode)) {
2868                 /*
2869                  * Windows 7 server can delay breaking level2 oplock if a write
2870                  * request comes - break it on the client to prevent reading
2871                  * an old data.
2872                  */
2873                 cifs_zap_mapping(inode);
2874                 cifs_dbg(FYI, "Set no oplock for inode=%p after a write operation\n",
2875                          inode);
2876                 cinode->oplock = 0;
2877         }
2878 out:
2879         cifs_put_writer(cinode);
2880         return written;
2881 }
2882
2883 static struct cifs_readdata *
2884 cifs_readdata_alloc(unsigned int nr_pages, work_func_t complete)
2885 {
2886         struct cifs_readdata *rdata;
2887
2888         rdata = kzalloc(sizeof(*rdata) + (sizeof(struct page *) * nr_pages),
2889                         GFP_KERNEL);
2890         if (rdata != NULL) {
2891                 kref_init(&rdata->refcount);
2892                 INIT_LIST_HEAD(&rdata->list);
2893                 init_completion(&rdata->done);
2894                 INIT_WORK(&rdata->work, complete);
2895         }
2896
2897         return rdata;
2898 }
2899
2900 void
2901 cifs_readdata_release(struct kref *refcount)
2902 {
2903         struct cifs_readdata *rdata = container_of(refcount,
2904                                         struct cifs_readdata, refcount);
2905
2906         if (rdata->cfile)
2907                 cifsFileInfo_put(rdata->cfile);
2908
2909         kfree(rdata);
2910 }
2911
2912 static int
2913 cifs_read_allocate_pages(struct cifs_readdata *rdata, unsigned int nr_pages)
2914 {
2915         int rc = 0;
2916         struct page *page;
2917         unsigned int i;
2918
2919         for (i = 0; i < nr_pages; i++) {
2920                 page = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
2921                 if (!page) {
2922                         rc = -ENOMEM;
2923                         break;
2924                 }
2925                 rdata->pages[i] = page;
2926         }
2927
2928         if (rc) {
2929                 for (i = 0; i < nr_pages; i++) {
2930                         put_page(rdata->pages[i]);
2931                         rdata->pages[i] = NULL;
2932                 }
2933         }
2934         return rc;
2935 }
2936
2937 static void
2938 cifs_uncached_readdata_release(struct kref *refcount)
2939 {
2940         struct cifs_readdata *rdata = container_of(refcount,
2941                                         struct cifs_readdata, refcount);
2942         unsigned int i;
2943
2944         kref_put(&rdata->ctx->refcount, cifs_aio_ctx_release);
2945         for (i = 0; i < rdata->nr_pages; i++) {
2946                 put_page(rdata->pages[i]);
2947                 rdata->pages[i] = NULL;
2948         }
2949         cifs_readdata_release(refcount);
2950 }
2951
2952 /**
2953  * cifs_readdata_to_iov - copy data from pages in response to an iovec
2954  * @rdata:      the readdata response with list of pages holding data
2955  * @iter:       destination for our data
2956  *
2957  * This function copies data from a list of pages in a readdata response into
2958  * an array of iovecs. It will first calculate where the data should go
2959  * based on the info in the readdata and then copy the data into that spot.
2960  */
2961 static int
2962 cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter)
2963 {
2964         size_t remaining = rdata->got_bytes;
2965         unsigned int i;
2966
2967         for (i = 0; i < rdata->nr_pages; i++) {
2968                 struct page *page = rdata->pages[i];
2969                 size_t copy = min_t(size_t, remaining, PAGE_SIZE);
2970                 size_t written;
2971
2972                 if (unlikely(iter->type & ITER_PIPE)) {
2973                         void *addr = kmap_atomic(page);
2974
2975                         written = copy_to_iter(addr, copy, iter);
2976                         kunmap_atomic(addr);
2977                 } else
2978                         written = copy_page_to_iter(page, 0, copy, iter);
2979                 remaining -= written;
2980                 if (written < copy && iov_iter_count(iter) > 0)
2981                         break;
2982         }
2983         return remaining ? -EFAULT : 0;
2984 }
2985
2986 static void collect_uncached_read_data(struct cifs_aio_ctx *ctx);
2987
2988 static void
2989 cifs_uncached_readv_complete(struct work_struct *work)
2990 {
2991         struct cifs_readdata *rdata = container_of(work,
2992                                                 struct cifs_readdata, work);
2993
2994         complete(&rdata->done);
2995         collect_uncached_read_data(rdata->ctx);
2996         /* the below call can possibly free the last ref to aio ctx */
2997         kref_put(&rdata->refcount, cifs_uncached_readdata_release);
2998 }
2999
3000 static int
3001 uncached_fill_pages(struct TCP_Server_Info *server,
3002                     struct cifs_readdata *rdata, struct iov_iter *iter,
3003                     unsigned int len)
3004 {
3005         int result = 0;
3006         unsigned int i;
3007         unsigned int nr_pages = rdata->nr_pages;
3008
3009         rdata->got_bytes = 0;
3010         rdata->tailsz = PAGE_SIZE;
3011         for (i = 0; i < nr_pages; i++) {
3012                 struct page *page = rdata->pages[i];
3013                 size_t n;
3014
3015                 if (len <= 0) {
3016                         /* no need to hold page hostage */
3017                         rdata->pages[i] = NULL;
3018                         rdata->nr_pages--;
3019                         put_page(page);
3020                         continue;
3021                 }
3022                 n = len;
3023                 if (len >= PAGE_SIZE) {
3024                         /* enough data to fill the page */
3025                         n = PAGE_SIZE;
3026                         len -= n;
3027                 } else {
3028                         zero_user(page, len, PAGE_SIZE - len);
3029                         rdata->tailsz = len;
3030                         len = 0;
3031                 }
3032                 if (iter)
3033                         result = copy_page_from_iter(page, 0, n, iter);
3034                 else
3035                         result = cifs_read_page_from_socket(server, page, n);
3036                 if (result < 0)
3037                         break;
3038
3039                 rdata->got_bytes += result;
3040         }
3041
3042         return rdata->got_bytes > 0 && result != -ECONNABORTED ?
3043                                                 rdata->got_bytes : result;
3044 }
3045
3046 static int
3047 cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
3048                               struct cifs_readdata *rdata, unsigned int len)
3049 {
3050         return uncached_fill_pages(server, rdata, NULL, len);
3051 }
3052
3053 static int
3054 cifs_uncached_copy_into_pages(struct TCP_Server_Info *server,
3055                               struct cifs_readdata *rdata,
3056                               struct iov_iter *iter)
3057 {
3058         return uncached_fill_pages(server, rdata, iter, iter->count);
3059 }
3060
3061 static int
3062 cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
3063                      struct cifs_sb_info *cifs_sb, struct list_head *rdata_list,
3064                      struct cifs_aio_ctx *ctx)
3065 {
3066         struct cifs_readdata *rdata;
3067         unsigned int npages, rsize, credits;
3068         size_t cur_len;
3069         int rc;
3070         pid_t pid;
3071         struct TCP_Server_Info *server;
3072
3073         server = tlink_tcon(open_file->tlink)->ses->server;
3074
3075         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
3076                 pid = open_file->pid;
3077         else
3078                 pid = current->tgid;
3079
3080         do {
3081                 rc = server->ops->wait_mtu_credits(server, cifs_sb->rsize,
3082                                                    &rsize, &credits);
3083                 if (rc)
3084                         break;
3085
3086                 cur_len = min_t(const size_t, len, rsize);
3087                 npages = DIV_ROUND_UP(cur_len, PAGE_SIZE);
3088
3089                 /* allocate a readdata struct */
3090                 rdata = cifs_readdata_alloc(npages,
3091                                             cifs_uncached_readv_complete);
3092                 if (!rdata) {
3093                         add_credits_and_wake_if(server, credits, 0);
3094                         rc = -ENOMEM;
3095                         break;
3096                 }
3097
3098                 rc = cifs_read_allocate_pages(rdata, npages);
3099                 if (rc)
3100                         goto error;
3101
3102                 rdata->cfile = cifsFileInfo_get(open_file);
3103                 rdata->nr_pages = npages;
3104                 rdata->offset = offset;
3105                 rdata->bytes = cur_len;
3106                 rdata->pid = pid;
3107                 rdata->pagesz = PAGE_SIZE;
3108                 rdata->read_into_pages = cifs_uncached_read_into_pages;
3109                 rdata->copy_into_pages = cifs_uncached_copy_into_pages;
3110                 rdata->credits = credits;
3111                 rdata->ctx = ctx;
3112                 kref_get(&ctx->refcount);
3113
3114                 if (!rdata->cfile->invalidHandle ||
3115                     !(rc = cifs_reopen_file(rdata->cfile, true)))
3116                         rc = server->ops->async_readv(rdata);
3117 error:
3118                 if (rc) {
3119                         add_credits_and_wake_if(server, rdata->credits, 0);
3120                         kref_put(&rdata->refcount,
3121                                  cifs_uncached_readdata_release);
3122                         if (rc == -EAGAIN)
3123                                 continue;
3124                         break;
3125                 }
3126
3127                 list_add_tail(&rdata->list, rdata_list);
3128                 offset += cur_len;
3129                 len -= cur_len;
3130         } while (len > 0);
3131
3132         return rc;
3133 }
3134
3135 static void
3136 collect_uncached_read_data(struct cifs_aio_ctx *ctx)
3137 {
3138         struct cifs_readdata *rdata, *tmp;
3139         struct iov_iter *to = &ctx->iter;
3140         struct cifs_sb_info *cifs_sb;
3141         struct cifs_tcon *tcon;
3142         unsigned int i;
3143         int rc;
3144
3145         tcon = tlink_tcon(ctx->cfile->tlink);
3146         cifs_sb = CIFS_SB(ctx->cfile->dentry->d_sb);
3147
3148         mutex_lock(&ctx->aio_mutex);
3149
3150         if (list_empty(&ctx->list)) {
3151                 mutex_unlock(&ctx->aio_mutex);
3152                 return;
3153         }
3154
3155         rc = ctx->rc;
3156         /* the loop below should proceed in the order of increasing offsets */
3157 again:
3158         list_for_each_entry_safe(rdata, tmp, &ctx->list, list) {
3159                 if (!rc) {
3160                         if (!try_wait_for_completion(&rdata->done)) {
3161                                 mutex_unlock(&ctx->aio_mutex);
3162                                 return;
3163                         }
3164
3165                         if (rdata->result == -EAGAIN) {
3166                                 /* resend call if it's a retryable error */
3167                                 struct list_head tmp_list;
3168                                 unsigned int got_bytes = rdata->got_bytes;
3169
3170                                 list_del_init(&rdata->list);
3171                                 INIT_LIST_HEAD(&tmp_list);
3172
3173                                 /*
3174                                  * Got a part of data and then reconnect has
3175                                  * happened -- fill the buffer and continue
3176                                  * reading.
3177                                  */
3178                                 if (got_bytes && got_bytes < rdata->bytes) {
3179                                         rc = cifs_readdata_to_iov(rdata, to);
3180                                         if (rc) {
3181                                                 kref_put(&rdata->refcount,
3182                                                 cifs_uncached_readdata_release);
3183                                                 continue;
3184                                         }
3185                                 }
3186
3187                                 rc = cifs_send_async_read(
3188                                                 rdata->offset + got_bytes,
3189                                                 rdata->bytes - got_bytes,
3190                                                 rdata->cfile, cifs_sb,
3191                                                 &tmp_list, ctx);
3192
3193                                 list_splice(&tmp_list, &ctx->list);
3194
3195                                 kref_put(&rdata->refcount,
3196                                          cifs_uncached_readdata_release);
3197                                 goto again;
3198                         } else if (rdata->result)
3199                                 rc = rdata->result;
3200                         else
3201                                 rc = cifs_readdata_to_iov(rdata, to);
3202
3203                         /* if there was a short read -- discard anything left */
3204                         if (rdata->got_bytes && rdata->got_bytes < rdata->bytes)
3205                                 rc = -ENODATA;
3206                 }
3207                 list_del_init(&rdata->list);
3208                 kref_put(&rdata->refcount, cifs_uncached_readdata_release);
3209         }
3210
3211         for (i = 0; i < ctx->npages; i++) {
3212                 if (ctx->should_dirty)
3213                         set_page_dirty(ctx->bv[i].bv_page);
3214                 put_page(ctx->bv[i].bv_page);
3215         }
3216
3217         ctx->total_len = ctx->len - iov_iter_count(to);
3218
3219         cifs_stats_bytes_read(tcon, ctx->total_len);
3220
3221         /* mask nodata case */
3222         if (rc == -ENODATA)
3223                 rc = 0;
3224
3225         ctx->rc = (rc == 0) ? ctx->total_len : rc;
3226
3227         mutex_unlock(&ctx->aio_mutex);
3228
3229         if (ctx->iocb && ctx->iocb->ki_complete)
3230                 ctx->iocb->ki_complete(ctx->iocb, ctx->rc, 0);
3231         else
3232                 complete(&ctx->done);
3233 }
3234
3235 ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to)
3236 {
3237         struct file *file = iocb->ki_filp;
3238         ssize_t rc;
3239         size_t len;
3240         ssize_t total_read = 0;
3241         loff_t offset = iocb->ki_pos;
3242         struct cifs_sb_info *cifs_sb;
3243         struct cifs_tcon *tcon;
3244         struct cifsFileInfo *cfile;
3245         struct cifs_aio_ctx *ctx;
3246
3247         len = iov_iter_count(to);
3248         if (!len)
3249                 return 0;
3250
3251         cifs_sb = CIFS_FILE_SB(file);
3252         cfile = file->private_data;
3253         tcon = tlink_tcon(cfile->tlink);
3254
3255         if (!tcon->ses->server->ops->async_readv)
3256                 return -ENOSYS;
3257
3258         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
3259                 cifs_dbg(FYI, "attempting read on write only file instance\n");
3260
3261         ctx = cifs_aio_ctx_alloc();
3262         if (!ctx)
3263                 return -ENOMEM;
3264
3265         ctx->cfile = cifsFileInfo_get(cfile);
3266
3267         if (!is_sync_kiocb(iocb))
3268                 ctx->iocb = iocb;
3269
3270         if (to->type == ITER_IOVEC)
3271                 ctx->should_dirty = true;
3272
3273         rc = setup_aio_ctx_iter(ctx, to, READ);
3274         if (rc) {
3275                 kref_put(&ctx->refcount, cifs_aio_ctx_release);
3276                 return rc;
3277         }
3278
3279         len = ctx->len;
3280
3281         /* grab a lock here due to read response handlers can access ctx */
3282         mutex_lock(&ctx->aio_mutex);
3283
3284         rc = cifs_send_async_read(offset, len, cfile, cifs_sb, &ctx->list, ctx);
3285
3286         /* if at least one read request send succeeded, then reset rc */
3287         if (!list_empty(&ctx->list))
3288                 rc = 0;
3289
3290         mutex_unlock(&ctx->aio_mutex);
3291
3292         if (rc) {
3293                 kref_put(&ctx->refcount, cifs_aio_ctx_release);
3294                 return rc;
3295         }
3296
3297         if (!is_sync_kiocb(iocb)) {
3298                 kref_put(&ctx->refcount, cifs_aio_ctx_release);
3299                 return -EIOCBQUEUED;
3300         }
3301
3302         rc = wait_for_completion_killable(&ctx->done);
3303         if (rc) {
3304                 mutex_lock(&ctx->aio_mutex);
3305                 ctx->rc = rc = -EINTR;
3306                 total_read = ctx->total_len;
3307                 mutex_unlock(&ctx->aio_mutex);
3308         } else {
3309                 rc = ctx->rc;
3310                 total_read = ctx->total_len;
3311         }
3312
3313         kref_put(&ctx->refcount, cifs_aio_ctx_release);
3314
3315         if (total_read) {
3316                 iocb->ki_pos += total_read;
3317                 return total_read;
3318         }
3319         return rc;
3320 }
3321
3322 ssize_t
3323 cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to)
3324 {
3325         struct inode *inode = file_inode(iocb->ki_filp);
3326         struct cifsInodeInfo *cinode = CIFS_I(inode);
3327         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
3328         struct cifsFileInfo *cfile = (struct cifsFileInfo *)
3329                                                 iocb->ki_filp->private_data;
3330         struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
3331         int rc = -EACCES;
3332
3333         /*
3334          * In strict cache mode we need to read from the server all the time
3335          * if we don't have level II oplock because the server can delay mtime
3336          * change - so we can't make a decision about inode invalidating.
3337          * And we can also fail with pagereading if there are mandatory locks
3338          * on pages affected by this read but not on the region from pos to
3339          * pos+len-1.
3340          */
3341         if (!CIFS_CACHE_READ(cinode))
3342                 return cifs_user_readv(iocb, to);
3343
3344         if (cap_unix(tcon->ses) &&
3345             (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
3346             ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
3347                 return generic_file_read_iter(iocb, to);
3348
3349         /*
3350          * We need to hold the sem to be sure nobody modifies lock list
3351          * with a brlock that prevents reading.
3352          */
3353         down_read(&cinode->lock_sem);
3354         if (!cifs_find_lock_conflict(cfile, iocb->ki_pos, iov_iter_count(to),
3355                                      tcon->ses->server->vals->shared_lock_type,
3356                                      NULL, CIFS_READ_OP))
3357                 rc = generic_file_read_iter(iocb, to);
3358         up_read(&cinode->lock_sem);
3359         return rc;
3360 }
3361
3362 static ssize_t
3363 cifs_read(struct file *file, char *read_data, size_t read_size, loff_t *offset)
3364 {
3365         int rc = -EACCES;
3366         unsigned int bytes_read = 0;
3367         unsigned int total_read;
3368         unsigned int current_read_size;
3369         unsigned int rsize;
3370         struct cifs_sb_info *cifs_sb;
3371         struct cifs_tcon *tcon;
3372         struct TCP_Server_Info *server;
3373         unsigned int xid;
3374         char *cur_offset;
3375         struct cifsFileInfo *open_file;
3376         struct cifs_io_parms io_parms;
3377         int buf_type = CIFS_NO_BUFFER;
3378         __u32 pid;
3379
3380         xid = get_xid();
3381         cifs_sb = CIFS_FILE_SB(file);
3382
3383         /* FIXME: set up handlers for larger reads and/or convert to async */
3384         rsize = min_t(unsigned int, cifs_sb->rsize, CIFSMaxBufSize);
3385
3386         if (file->private_data == NULL) {
3387                 rc = -EBADF;
3388                 free_xid(xid);
3389                 return rc;
3390         }
3391         open_file = file->private_data;
3392         tcon = tlink_tcon(open_file->tlink);
3393         server = tcon->ses->server;
3394
3395         if (!server->ops->sync_read) {
3396                 free_xid(xid);
3397                 return -ENOSYS;
3398         }
3399
3400         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
3401                 pid = open_file->pid;
3402         else
3403                 pid = current->tgid;
3404
3405         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
3406                 cifs_dbg(FYI, "attempting read on write only file instance\n");
3407
3408         for (total_read = 0, cur_offset = read_data; read_size > total_read;
3409              total_read += bytes_read, cur_offset += bytes_read) {
3410                 do {
3411                         current_read_size = min_t(uint, read_size - total_read,
3412                                                   rsize);
3413                         /*
3414                          * For windows me and 9x we do not want to request more
3415                          * than it negotiated since it will refuse the read
3416                          * then.
3417                          */
3418                         if ((tcon->ses) && !(tcon->ses->capabilities &
3419                                 tcon->ses->server->vals->cap_large_files)) {
3420                                 current_read_size = min_t(uint,
3421                                         current_read_size, CIFSMaxBufSize);
3422                         }
3423                         if (open_file->invalidHandle) {
3424                                 rc = cifs_reopen_file(open_file, true);
3425                                 if (rc != 0)
3426                                         break;
3427                         }
3428                         io_parms.pid = pid;
3429                         io_parms.tcon = tcon;
3430                         io_parms.offset = *offset;
3431                         io_parms.length = current_read_size;
3432                         rc = server->ops->sync_read(xid, &open_file->fid, &io_parms,
3433                                                     &bytes_read, &cur_offset,
3434                                                     &buf_type);
3435                 } while (rc == -EAGAIN);
3436
3437                 if (rc || (bytes_read == 0)) {
3438                         if (total_read) {
3439                                 break;
3440                         } else {
3441                                 free_xid(xid);
3442                                 return rc;
3443                         }
3444                 } else {
3445                         cifs_stats_bytes_read(tcon, total_read);
3446                         *offset += bytes_read;
3447                 }
3448         }
3449         free_xid(xid);
3450         return total_read;
3451 }
3452
3453 /*
3454  * If the page is mmap'ed into a process' page tables, then we need to make
3455  * sure that it doesn't change while being written back.
3456  */
3457 static int
3458 cifs_page_mkwrite(struct vm_fault *vmf)
3459 {
3460         struct page *page = vmf->page;
3461
3462         lock_page(page);
3463         return VM_FAULT_LOCKED;
3464 }
3465
3466 static const struct vm_operations_struct cifs_file_vm_ops = {
3467         .fault = filemap_fault,
3468         .map_pages = filemap_map_pages,
3469         .page_mkwrite = cifs_page_mkwrite,
3470 };
3471
3472 int cifs_file_strict_mmap(struct file *file, struct vm_area_struct *vma)
3473 {
3474         int rc, xid;
3475         struct inode *inode = file_inode(file);
3476
3477         xid = get_xid();
3478
3479         if (!CIFS_CACHE_READ(CIFS_I(inode))) {
3480                 rc = cifs_zap_mapping(inode);
3481                 if (rc)
3482                         return rc;
3483         }
3484
3485         rc = generic_file_mmap(file, vma);
3486         if (rc == 0)
3487                 vma->vm_ops = &cifs_file_vm_ops;
3488         free_xid(xid);
3489         return rc;
3490 }
3491
3492 int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
3493 {
3494         int rc, xid;
3495
3496         xid = get_xid();
3497         rc = cifs_revalidate_file(file);
3498         if (rc) {
3499                 cifs_dbg(FYI, "Validation prior to mmap failed, error=%d\n",
3500                          rc);
3501                 free_xid(xid);
3502                 return rc;
3503         }
3504         rc = generic_file_mmap(file, vma);
3505         if (rc == 0)
3506                 vma->vm_ops = &cifs_file_vm_ops;
3507         free_xid(xid);
3508         return rc;
3509 }
3510
3511 static void
3512 cifs_readv_complete(struct work_struct *work)
3513 {
3514         unsigned int i, got_bytes;
3515         struct cifs_readdata *rdata = container_of(work,
3516                                                 struct cifs_readdata, work);
3517
3518         got_bytes = rdata->got_bytes;
3519         for (i = 0; i < rdata->nr_pages; i++) {
3520                 struct page *page = rdata->pages[i];
3521
3522                 lru_cache_add_file(page);
3523
3524                 if (rdata->result == 0 ||
3525                     (rdata->result == -EAGAIN && got_bytes)) {
3526                         flush_dcache_page(page);
3527                         SetPageUptodate(page);
3528                 }
3529
3530                 unlock_page(page);
3531
3532                 if (rdata->result == 0 ||
3533                     (rdata->result == -EAGAIN && got_bytes))
3534                         cifs_readpage_to_fscache(rdata->mapping->host, page);
3535
3536                 got_bytes -= min_t(unsigned int, PAGE_SIZE, got_bytes);
3537
3538                 put_page(page);
3539                 rdata->pages[i] = NULL;
3540         }
3541         kref_put(&rdata->refcount, cifs_readdata_release);
3542 }
3543
3544 static int
3545 readpages_fill_pages(struct TCP_Server_Info *server,
3546                      struct cifs_readdata *rdata, struct iov_iter *iter,
3547                      unsigned int len)
3548 {
3549         int result = 0;
3550         unsigned int i;
3551         u64 eof;
3552         pgoff_t eof_index;
3553         unsigned int nr_pages = rdata->nr_pages;
3554
3555         /* determine the eof that the server (probably) has */
3556         eof = CIFS_I(rdata->mapping->host)->server_eof;
3557         eof_index = eof ? (eof - 1) >> PAGE_SHIFT : 0;
3558         cifs_dbg(FYI, "eof=%llu eof_index=%lu\n", eof, eof_index);
3559
3560         rdata->got_bytes = 0;
3561         rdata->tailsz = PAGE_SIZE;
3562         for (i = 0; i < nr_pages; i++) {
3563                 struct page *page = rdata->pages[i];
3564                 size_t n = PAGE_SIZE;
3565
3566                 if (len >= PAGE_SIZE) {
3567                         len -= PAGE_SIZE;
3568                 } else if (len > 0) {
3569                         /* enough for partial page, fill and zero the rest */
3570                         zero_user(page, len, PAGE_SIZE - len);
3571                         n = rdata->tailsz = len;
3572                         len = 0;
3573                 } else if (page->index > eof_index) {
3574                         /*
3575                          * The VFS will not try to do readahead past the
3576                          * i_size, but it's possible that we have outstanding
3577                          * writes with gaps in the middle and the i_size hasn't
3578                          * caught up yet. Populate those with zeroed out pages
3579                          * to prevent the VFS from repeatedly attempting to
3580                          * fill them until the writes are flushed.
3581                          */
3582                         zero_user(page, 0, PAGE_SIZE);
3583                         lru_cache_add_file(page);
3584                         flush_dcache_page(page);
3585                         SetPageUptodate(page);
3586                         unlock_page(page);
3587                         put_page(page);
3588                         rdata->pages[i] = NULL;
3589                         rdata->nr_pages--;
3590                         continue;
3591                 } else {
3592                         /* no need to hold page hostage */
3593                         lru_cache_add_file(page);
3594                         unlock_page(page);
3595                         put_page(page);
3596                         rdata->pages[i] = NULL;
3597                         rdata->nr_pages--;
3598                         continue;
3599                 }
3600
3601                 if (iter)
3602                         result = copy_page_from_iter(page, 0, n, iter);
3603                 else
3604                         result = cifs_read_page_from_socket(server, page, n);
3605                 if (result < 0)
3606                         break;
3607
3608                 rdata->got_bytes += result;
3609         }
3610
3611         return rdata->got_bytes > 0 && result != -ECONNABORTED ?
3612                                                 rdata->got_bytes : result;
3613 }
3614
3615 static int
3616 cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
3617                                struct cifs_readdata *rdata, unsigned int len)
3618 {
3619         return readpages_fill_pages(server, rdata, NULL, len);
3620 }
3621
3622 static int
3623 cifs_readpages_copy_into_pages(struct TCP_Server_Info *server,
3624                                struct cifs_readdata *rdata,
3625                                struct iov_iter *iter)
3626 {
3627         return readpages_fill_pages(server, rdata, iter, iter->count);
3628 }
3629
3630 static int
3631 readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
3632                     unsigned int rsize, struct list_head *tmplist,
3633                     unsigned int *nr_pages, loff_t *offset, unsigned int *bytes)
3634 {
3635         struct page *page, *tpage;
3636         unsigned int expected_index;
3637         int rc;
3638         gfp_t gfp = readahead_gfp_mask(mapping);
3639
3640         INIT_LIST_HEAD(tmplist);
3641
3642         page = list_entry(page_list->prev, struct page, lru);
3643
3644         /*
3645          * Lock the page and put it in the cache. Since no one else
3646          * should have access to this page, we're safe to simply set
3647          * PG_locked without checking it first.
3648          */
3649         __SetPageLocked(page);
3650         rc = add_to_page_cache_locked(page, mapping,
3651                                       page->index, gfp);
3652
3653         /* give up if we can't stick it in the cache */
3654         if (rc) {
3655                 __ClearPageLocked(page);
3656                 return rc;
3657         }
3658
3659         /* move first page to the tmplist */
3660         *offset = (loff_t)page->index << PAGE_SHIFT;
3661         *bytes = PAGE_SIZE;
3662         *nr_pages = 1;
3663         list_move_tail(&page->lru, tmplist);
3664
3665         /* now try and add more pages onto the request */
3666         expected_index = page->index + 1;
3667         list_for_each_entry_safe_reverse(page, tpage, page_list, lru) {
3668                 /* discontinuity ? */
3669                 if (page->index != expected_index)
3670                         break;
3671
3672                 /* would this page push the read over the rsize? */
3673                 if (*bytes + PAGE_SIZE > rsize)
3674                         break;
3675
3676                 __SetPageLocked(page);
3677                 if (add_to_page_cache_locked(page, mapping, page->index, gfp)) {
3678                         __ClearPageLocked(page);
3679                         break;
3680                 }
3681                 list_move_tail(&page->lru, tmplist);
3682                 (*bytes) += PAGE_SIZE;
3683                 expected_index++;
3684                 (*nr_pages)++;
3685         }
3686         return rc;
3687 }
3688
3689 static int cifs_readpages(struct file *file, struct address_space *mapping,
3690         struct list_head *page_list, unsigned num_pages)
3691 {
3692         int rc;
3693         struct list_head tmplist;
3694         struct cifsFileInfo *open_file = file->private_data;
3695         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
3696         struct TCP_Server_Info *server;
3697         pid_t pid;
3698
3699         /*
3700          * Reads as many pages as possible from fscache. Returns -ENOBUFS
3701          * immediately if the cookie is negative
3702          *
3703          * After this point, every page in the list might have PG_fscache set,
3704          * so we will need to clean that up off of every page we don't use.
3705          */
3706         rc = cifs_readpages_from_fscache(mapping->host, mapping, page_list,
3707                                          &num_pages);
3708         if (rc == 0)
3709                 return rc;
3710
3711         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
3712                 pid = open_file->pid;
3713         else
3714                 pid = current->tgid;
3715
3716         rc = 0;
3717         server = tlink_tcon(open_file->tlink)->ses->server;
3718
3719         cifs_dbg(FYI, "%s: file=%p mapping=%p num_pages=%u\n",
3720                  __func__, file, mapping, num_pages);
3721
3722         /*
3723          * Start with the page at end of list and move it to private
3724          * list. Do the same with any following pages until we hit
3725          * the rsize limit, hit an index discontinuity, or run out of
3726          * pages. Issue the async read and then start the loop again
3727          * until the list is empty.
3728          *
3729          * Note that list order is important. The page_list is in
3730          * the order of declining indexes. When we put the pages in
3731          * the rdata->pages, then we want them in increasing order.
3732          */
3733         while (!list_empty(page_list)) {
3734                 unsigned int i, nr_pages, bytes, rsize;
3735                 loff_t offset;
3736                 struct page *page, *tpage;
3737                 struct cifs_readdata *rdata;
3738                 unsigned credits;
3739
3740                 rc = server->ops->wait_mtu_credits(server, cifs_sb->rsize,
3741                                                    &rsize, &credits);
3742                 if (rc)
3743                         break;
3744
3745                 /*
3746                  * Give up immediately if rsize is too small to read an entire
3747                  * page. The VFS will fall back to readpage. We should never
3748                  * reach this point however since we set ra_pages to 0 when the
3749                  * rsize is smaller than a cache page.
3750                  */
3751                 if (unlikely(rsize < PAGE_SIZE)) {
3752                         add_credits_and_wake_if(server, credits, 0);
3753                         return 0;
3754                 }
3755
3756                 rc = readpages_get_pages(mapping, page_list, rsize, &tmplist,
3757                                          &nr_pages, &offset, &bytes);
3758                 if (rc) {
3759                         add_credits_and_wake_if(server, credits, 0);
3760                         break;
3761                 }
3762
3763                 rdata = cifs_readdata_alloc(nr_pages, cifs_readv_complete);
3764                 if (!rdata) {
3765                         /* best to give up if we're out of mem */
3766                         list_for_each_entry_safe(page, tpage, &tmplist, lru) {
3767                                 list_del(&page->lru);
3768                                 lru_cache_add_file(page);
3769                                 unlock_page(page);
3770                                 put_page(page);
3771                         }
3772                         rc = -ENOMEM;
3773                         add_credits_and_wake_if(server, credits, 0);
3774                         break;
3775                 }
3776
3777                 rdata->cfile = cifsFileInfo_get(open_file);
3778                 rdata->mapping = mapping;
3779                 rdata->offset = offset;
3780                 rdata->bytes = bytes;
3781                 rdata->pid = pid;
3782                 rdata->pagesz = PAGE_SIZE;
3783                 rdata->read_into_pages = cifs_readpages_read_into_pages;
3784                 rdata->copy_into_pages = cifs_readpages_copy_into_pages;
3785                 rdata->credits = credits;
3786
3787                 list_for_each_entry_safe(page, tpage, &tmplist, lru) {
3788                         list_del(&page->lru);
3789                         rdata->pages[rdata->nr_pages++] = page;
3790                 }
3791
3792                 if (!rdata->cfile->invalidHandle ||
3793                     !(rc = cifs_reopen_file(rdata->cfile, true)))
3794                         rc = server->ops->async_readv(rdata);
3795                 if (rc) {
3796                         add_credits_and_wake_if(server, rdata->credits, 0);
3797                         for (i = 0; i < rdata->nr_pages; i++) {
3798                                 page = rdata->pages[i];
3799                                 lru_cache_add_file(page);
3800                                 unlock_page(page);
3801                                 put_page(page);
3802                         }
3803                         /* Fallback to the readpage in error/reconnect cases */
3804                         kref_put(&rdata->refcount, cifs_readdata_release);
3805                         break;
3806                 }
3807
3808                 kref_put(&rdata->refcount, cifs_readdata_release);
3809         }
3810
3811         /* Any pages that have been shown to fscache but didn't get added to
3812          * the pagecache must be uncached before they get returned to the
3813          * allocator.
3814          */
3815         cifs_fscache_readpages_cancel(mapping->host, page_list);
3816         return rc;
3817 }
3818
3819 /*
3820  * cifs_readpage_worker must be called with the page pinned
3821  */
3822 static int cifs_readpage_worker(struct file *file, struct page *page,
3823         loff_t *poffset)
3824 {
3825         char *read_data;
3826         int rc;
3827
3828         /* Is the page cached? */
3829         rc = cifs_readpage_from_fscache(file_inode(file), page);
3830         if (rc == 0)
3831                 goto read_complete;
3832
3833         read_data = kmap(page);
3834         /* for reads over a certain size could initiate async read ahead */
3835
3836         rc = cifs_read(file, read_data, PAGE_SIZE, poffset);
3837
3838         if (rc < 0)
3839                 goto io_error;
3840         else
3841                 cifs_dbg(FYI, "Bytes read %d\n", rc);
3842
3843         file_inode(file)->i_atime =
3844                 current_time(file_inode(file));
3845
3846         if (PAGE_SIZE > rc)
3847                 memset(read_data + rc, 0, PAGE_SIZE - rc);
3848
3849         flush_dcache_page(page);
3850         SetPageUptodate(page);
3851
3852         /* send this page to the cache */
3853         cifs_readpage_to_fscache(file_inode(file), page);
3854
3855         rc = 0;
3856
3857 io_error:
3858         kunmap(page);
3859         unlock_page(page);
3860
3861 read_complete:
3862         return rc;
3863 }
3864
3865 static int cifs_readpage(struct file *file, struct page *page)
3866 {
3867         loff_t offset = (loff_t)page->index << PAGE_SHIFT;
3868         int rc = -EACCES;
3869         unsigned int xid;
3870
3871         xid = get_xid();
3872
3873         if (file->private_data == NULL) {
3874                 rc = -EBADF;
3875                 free_xid(xid);
3876                 return rc;
3877         }
3878
3879         cifs_dbg(FYI, "readpage %p at offset %d 0x%x\n",
3880                  page, (int)offset, (int)offset);
3881
3882         rc = cifs_readpage_worker(file, page, &offset);
3883
3884         free_xid(xid);
3885         return rc;
3886 }
3887
3888 static int is_inode_writable(struct cifsInodeInfo *cifs_inode)
3889 {
3890         struct cifsFileInfo *open_file;
3891         struct cifs_tcon *tcon =
3892                 cifs_sb_master_tcon(CIFS_SB(cifs_inode->vfs_inode.i_sb));
3893
3894         spin_lock(&tcon->open_file_lock);
3895         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
3896                 if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
3897                         spin_unlock(&tcon->open_file_lock);
3898                         return 1;
3899                 }
3900         }
3901         spin_unlock(&tcon->open_file_lock);
3902         return 0;
3903 }
3904
3905 /* We do not want to update the file size from server for inodes
3906    open for write - to avoid races with writepage extending
3907    the file - in the future we could consider allowing
3908    refreshing the inode only on increases in the file size
3909    but this is tricky to do without racing with writebehind
3910    page caching in the current Linux kernel design */
3911 bool is_size_safe_to_change(struct cifsInodeInfo *cifsInode, __u64 end_of_file)
3912 {
3913         if (!cifsInode)
3914                 return true;
3915
3916         if (is_inode_writable(cifsInode)) {
3917                 /* This inode is open for write at least once */
3918                 struct cifs_sb_info *cifs_sb;
3919
3920                 cifs_sb = CIFS_SB(cifsInode->vfs_inode.i_sb);
3921                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO) {
3922                         /* since no page cache to corrupt on directio
3923                         we can change size safely */
3924                         return true;
3925                 }
3926
3927                 if (i_size_read(&cifsInode->vfs_inode) < end_of_file)
3928                         return true;
3929
3930                 return false;
3931         } else
3932                 return true;
3933 }
3934
3935 static int cifs_write_begin(struct file *file, struct address_space *mapping,
3936                         loff_t pos, unsigned len, unsigned flags,
3937                         struct page **pagep, void **fsdata)
3938 {
3939         int oncethru = 0;
3940         pgoff_t index = pos >> PAGE_SHIFT;
3941         loff_t offset = pos & (PAGE_SIZE - 1);
3942         loff_t page_start = pos & PAGE_MASK;
3943         loff_t i_size;
3944         struct page *page;
3945         int rc = 0;
3946
3947         cifs_dbg(FYI, "write_begin from %lld len %d\n", (long long)pos, len);
3948
3949 start:
3950         page = grab_cache_page_write_begin(mapping, index, flags);
3951         if (!page) {
3952                 rc = -ENOMEM;
3953                 goto out;
3954         }
3955
3956         if (PageUptodate(page))
3957                 goto out;
3958
3959         /*
3960          * If we write a full page it will be up to date, no need to read from
3961          * the server. If the write is short, we'll end up doing a sync write
3962          * instead.
3963          */
3964         if (len == PAGE_SIZE)
3965                 goto out;
3966
3967         /*
3968          * optimize away the read when we have an oplock, and we're not
3969          * expecting to use any of the data we'd be reading in. That
3970          * is, when the page lies beyond the EOF, or straddles the EOF
3971          * and the write will cover all of the existing data.
3972          */
3973         if (CIFS_CACHE_READ(CIFS_I(mapping->host))) {
3974                 i_size = i_size_read(mapping->host);
3975                 if (page_start >= i_size ||
3976                     (offset == 0 && (pos + len) >= i_size)) {
3977                         zero_user_segments(page, 0, offset,
3978                                            offset + len,
3979                                            PAGE_SIZE);
3980                         /*
3981                          * PageChecked means that the parts of the page
3982                          * to which we're not writing are considered up
3983                          * to date. Once the data is copied to the
3984                          * page, it can be set uptodate.
3985                          */
3986                         SetPageChecked(page);
3987                         goto out;
3988                 }
3989         }
3990
3991         if ((file->f_flags & O_ACCMODE) != O_WRONLY && !oncethru) {
3992                 /*
3993                  * might as well read a page, it is fast enough. If we get
3994                  * an error, we don't need to return it. cifs_write_end will
3995                  * do a sync write instead since PG_uptodate isn't set.
3996                  */
3997                 cifs_readpage_worker(file, page, &page_start);
3998                 put_page(page);
3999                 oncethru = 1;
4000                 goto start;
4001         } else {
4002                 /* we could try using another file handle if there is one -
4003                    but how would we lock it to prevent close of that handle
4004                    racing with this read? In any case
4005                    this will be written out by write_end so is fine */
4006         }
4007 out:
4008         *pagep = page;
4009         return rc;
4010 }
4011
4012 static int cifs_release_page(struct page *page, gfp_t gfp)
4013 {
4014         if (PagePrivate(page))
4015                 return 0;
4016
4017         return cifs_fscache_release_page(page, gfp);
4018 }
4019
4020 static void cifs_invalidate_page(struct page *page, unsigned int offset,
4021                                  unsigned int length)
4022 {
4023         struct cifsInodeInfo *cifsi = CIFS_I(page->mapping->host);
4024
4025         if (offset == 0 && length == PAGE_SIZE)
4026                 cifs_fscache_invalidate_page(page, &cifsi->vfs_inode);
4027 }
4028
4029 static int cifs_launder_page(struct page *page)
4030 {
4031         int rc = 0;
4032         loff_t range_start = page_offset(page);
4033         loff_t range_end = range_start + (loff_t)(PAGE_SIZE - 1);
4034         struct writeback_control wbc = {
4035                 .sync_mode = WB_SYNC_ALL,
4036                 .nr_to_write = 0,
4037                 .range_start = range_start,
4038                 .range_end = range_end,
4039         };
4040
4041         cifs_dbg(FYI, "Launder page: %p\n", page);
4042
4043         if (clear_page_dirty_for_io(page))
4044                 rc = cifs_writepage_locked(page, &wbc);
4045
4046         cifs_fscache_invalidate_page(page, page->mapping->host);
4047         return rc;
4048 }
4049
4050 void cifs_oplock_break(struct work_struct *work)
4051 {
4052         struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
4053                                                   oplock_break);
4054         struct inode *inode = d_inode(cfile->dentry);
4055         struct cifsInodeInfo *cinode = CIFS_I(inode);
4056         struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
4057         struct TCP_Server_Info *server = tcon->ses->server;
4058         int rc = 0;
4059
4060         wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS,
4061                         TASK_UNINTERRUPTIBLE);
4062
4063         server->ops->downgrade_oplock(server, cinode,
4064                 test_bit(CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2, &cinode->flags));
4065
4066         if (!CIFS_CACHE_WRITE(cinode) && CIFS_CACHE_READ(cinode) &&
4067                                                 cifs_has_mand_locks(cinode)) {
4068                 cifs_dbg(FYI, "Reset oplock to None for inode=%p due to mand locks\n",
4069                          inode);
4070                 cinode->oplock = 0;
4071         }
4072
4073         if (inode && S_ISREG(inode->i_mode)) {
4074                 if (CIFS_CACHE_READ(cinode))
4075                         break_lease(inode, O_RDONLY);
4076                 else
4077                         break_lease(inode, O_WRONLY);
4078                 rc = filemap_fdatawrite(inode->i_mapping);
4079                 if (!CIFS_CACHE_READ(cinode)) {
4080                         rc = filemap_fdatawait(inode->i_mapping);
4081                         mapping_set_error(inode->i_mapping, rc);
4082                         cifs_zap_mapping(inode);
4083                 }
4084                 cifs_dbg(FYI, "Oplock flush inode %p rc %d\n", inode, rc);
4085         }
4086
4087         rc = cifs_push_locks(cfile);
4088         if (rc)
4089                 cifs_dbg(VFS, "Push locks rc = %d\n", rc);
4090
4091         /*
4092          * releasing stale oplock after recent reconnect of smb session using
4093          * a now incorrect file handle is not a data integrity issue but do
4094          * not bother sending an oplock release if session to server still is
4095          * disconnected since oplock already released by the server
4096          */
4097         if (!cfile->oplock_break_cancelled) {
4098                 rc = tcon->ses->server->ops->oplock_response(tcon, &cfile->fid,
4099                                                              cinode);
4100                 cifs_dbg(FYI, "Oplock release rc = %d\n", rc);
4101         }
4102         cifs_done_oplock_break(cinode);
4103 }
4104
4105 /*
4106  * The presence of cifs_direct_io() in the address space ops vector
4107  * allowes open() O_DIRECT flags which would have failed otherwise.
4108  *
4109  * In the non-cached mode (mount with cache=none), we shunt off direct read and write requests
4110  * so this method should never be called.
4111  *
4112  * Direct IO is not yet supported in the cached mode.
4113  */
4114 static ssize_t
4115 cifs_direct_io(struct kiocb *iocb, struct iov_iter *iter)
4116 {
4117         /*
4118          * FIXME
4119          * Eventually need to support direct IO for non forcedirectio mounts
4120          */
4121         return -EINVAL;
4122 }
4123
4124
4125 const struct address_space_operations cifs_addr_ops = {
4126         .readpage = cifs_readpage,
4127         .readpages = cifs_readpages,
4128         .writepage = cifs_writepage,
4129         .writepages = cifs_writepages,
4130         .write_begin = cifs_write_begin,
4131         .write_end = cifs_write_end,
4132         .set_page_dirty = __set_page_dirty_nobuffers,
4133         .releasepage = cifs_release_page,
4134         .direct_IO = cifs_direct_io,
4135         .invalidatepage = cifs_invalidate_page,
4136         .launder_page = cifs_launder_page,
4137 };
4138
4139 /*
4140  * cifs_readpages requires the server to support a buffer large enough to
4141  * contain the header plus one complete page of data.  Otherwise, we need
4142  * to leave cifs_readpages out of the address space operations.
4143  */
4144 const struct address_space_operations cifs_addr_ops_smallbuf = {
4145         .readpage = cifs_readpage,
4146         .writepage = cifs_writepage,
4147         .writepages = cifs_writepages,
4148         .write_begin = cifs_write_begin,
4149         .write_end = cifs_write_end,
4150         .set_page_dirty = __set_page_dirty_nobuffers,
4151         .releasepage = cifs_release_page,
4152         .invalidatepage = cifs_invalidate_page,
4153         .launder_page = cifs_launder_page,
4154 };