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 <asm/div64.h>
  36 #include "cifsfs.h"
  37 #include "cifspdu.h"
  38 #include "cifsglob.h"
  39 #include "cifsproto.h"
  40 #include "cifs_unicode.h"
  41 #include "cifs_debug.h"
  42 #include "cifs_fs_sb.h"
  43 #include "fscache.h"
  44
  45 static inline int cifs_convert_flags(unsigned int flags)
  46 {
  47         if ((flags & O_ACCMODE) == O_RDONLY)
  48                 return GENERIC_READ;
  49         else if ((flags & O_ACCMODE) == O_WRONLY)
  50                 return GENERIC_WRITE;
  51         else if ((flags & O_ACCMODE) == O_RDWR) {
  52                 /* GENERIC_ALL is too much permission to request
  53                    can cause unnecessary access denied on create */
  54                 /* return GENERIC_ALL; */
  55                 return (GENERIC_READ | GENERIC_WRITE);
  56         }
  57
  58         return (READ_CONTROL | FILE_WRITE_ATTRIBUTES | FILE_READ_ATTRIBUTES |
  59                 FILE_WRITE_EA | FILE_APPEND_DATA | FILE_WRITE_DATA |
  60                 FILE_READ_DATA);
  61 }
  62
  63 static u32 cifs_posix_convert_flags(unsigned int flags)
  64 {
  65         u32 posix_flags = 0;
  66
  67         if ((flags & O_ACCMODE) == O_RDONLY)
  68                 posix_flags = SMB_O_RDONLY;
  69         else if ((flags & O_ACCMODE) == O_WRONLY)
  70                 posix_flags = SMB_O_WRONLY;
  71         else if ((flags & O_ACCMODE) == O_RDWR)
  72                 posix_flags = SMB_O_RDWR;
  73
  74         if (flags & O_CREAT)
  75                 posix_flags |= SMB_O_CREAT;
  76         if (flags & O_EXCL)
  77                 posix_flags |= SMB_O_EXCL;
  78         if (flags & O_TRUNC)
  79                 posix_flags |= SMB_O_TRUNC;
  80         /* be safe and imply O_SYNC for O_DSYNC */
  81         if (flags & O_DSYNC)
  82                 posix_flags |= SMB_O_SYNC;
  83         if (flags & O_DIRECTORY)
  84                 posix_flags |= SMB_O_DIRECTORY;
  85         if (flags & O_NOFOLLOW)
  86                 posix_flags |= SMB_O_NOFOLLOW;
  87         if (flags & O_DIRECT)
  88                 posix_flags |= SMB_O_DIRECT;
  89
  90         return posix_flags;
  91 }
  92
  93 static inline int cifs_get_disposition(unsigned int flags)
  94 {
  95         if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
  96                 return FILE_CREATE;
  97         else if ((flags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
  98                 return FILE_OVERWRITE_IF;
  99         else if ((flags & O_CREAT) == O_CREAT)
 100                 return FILE_OPEN_IF;
 101         else if ((flags & O_TRUNC) == O_TRUNC)
 102                 return FILE_OVERWRITE;
 103         else
 104                 return FILE_OPEN;
 105 }
 106
 107 int cifs_posix_open(char *full_path, struct inode **pinode,
 108                         struct super_block *sb, int mode, unsigned int f_flags,
 109                         __u32 *poplock, __u16 *pnetfid, int xid)
 110 {
 111         int rc;
 112         FILE_UNIX_BASIC_INFO *presp_data;
 113         __u32 posix_flags = 0;
 114         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 115         struct cifs_fattr fattr;
 116         struct tcon_link *tlink;
 117         struct cifsTconInfo *tcon;
 118
 119         cFYI(1, "posix open %s", full_path);
 120
 121         presp_data = kzalloc(sizeof(FILE_UNIX_BASIC_INFO), GFP_KERNEL);
 122         if (presp_data == NULL)
 123                 return -ENOMEM;
 124
 125         tlink = cifs_sb_tlink(cifs_sb);
 126         if (IS_ERR(tlink)) {
 127                 rc = PTR_ERR(tlink);
 128                 goto posix_open_ret;
 129         }
 130
 131         tcon = tlink_tcon(tlink);
 132         mode &= ~current_umask();
 133
 134         posix_flags = cifs_posix_convert_flags(f_flags);
 135         rc = CIFSPOSIXCreate(xid, tcon, posix_flags, mode, pnetfid, presp_data,
 136                              poplock, full_path, cifs_sb->local_nls,
 137                              cifs_sb->mnt_cifs_flags &
 138                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
 139         cifs_put_tlink(tlink);
 140
 141         if (rc)
 142                 goto posix_open_ret;
 143
 144         if (presp_data->Type == cpu_to_le32(-1))
 145                 goto posix_open_ret; /* open ok, caller does qpathinfo */
 146
 147         if (!pinode)
 148                 goto posix_open_ret; /* caller does not need info */
 149
 150         cifs_unix_basic_to_fattr(&fattr, presp_data, cifs_sb);
 151
 152         /* get new inode and set it up */
 153         if (*pinode == NULL) {
 154                 cifs_fill_uniqueid(sb, &fattr);
 155                 *pinode = cifs_iget(sb, &fattr);
 156                 if (!*pinode) {
 157                         rc = -ENOMEM;
 158                         goto posix_open_ret;
 159                 }
 160         } else {
 161                 cifs_fattr_to_inode(*pinode, &fattr);
 162         }
 163
 164 posix_open_ret:
 165         kfree(presp_data);
 166         return rc;
 167 }
 168
 169 static int
 170 cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
 171              struct cifsTconInfo *tcon, unsigned int f_flags, __u32 *poplock,
 172              __u16 *pnetfid, int xid)
 173 {
 174         int rc;
 175         int desiredAccess;
 176         int disposition;
 177         FILE_ALL_INFO *buf;
 178
 179         desiredAccess = cifs_convert_flags(f_flags);
 180
 181 /*********************************************************************
 182  *  open flag mapping table:
 183  *
 184  *      POSIX Flag            CIFS Disposition
 185  *      ----------            ----------------
 186  *      O_CREAT               FILE_OPEN_IF
 187  *      O_CREAT | O_EXCL      FILE_CREATE
 188  *      O_CREAT | O_TRUNC     FILE_OVERWRITE_IF
 189  *      O_TRUNC               FILE_OVERWRITE
 190  *      none of the above     FILE_OPEN
 191  *
 192  *      Note that there is not a direct match between disposition
 193  *      FILE_SUPERSEDE (ie create whether or not file exists although
 194  *      O_CREAT | O_TRUNC is similar but truncates the existing
 195  *      file rather than creating a new file as FILE_SUPERSEDE does
 196  *      (which uses the attributes / metadata passed in on open call)
 197  *?
 198  *?  O_SYNC is a reasonable match to CIFS writethrough flag
 199  *?  and the read write flags match reasonably.  O_LARGEFILE
 200  *?  is irrelevant because largefile support is always used
 201  *?  by this client. Flags O_APPEND, O_DIRECT, O_DIRECTORY,
 202  *       O_FASYNC, O_NOFOLLOW, O_NONBLOCK need further investigation
 203  *********************************************************************/
 204
 205         disposition = cifs_get_disposition(f_flags);
 206
 207         /* BB pass O_SYNC flag through on file attributes .. BB */
 208
 209         buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 210         if (!buf)
 211                 return -ENOMEM;
 212
 213         if (tcon->ses->capabilities & CAP_NT_SMBS)
 214                 rc = CIFSSMBOpen(xid, tcon, full_path, disposition,
 215                          desiredAccess, CREATE_NOT_DIR, pnetfid, poplock, buf,
 216                          cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
 217                                  & CIFS_MOUNT_MAP_SPECIAL_CHR);
 218         else
 219                 rc = SMBLegacyOpen(xid, tcon, full_path, disposition,
 220                         desiredAccess, CREATE_NOT_DIR, pnetfid, poplock, buf,
 221                         cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
 222                                 & CIFS_MOUNT_MAP_SPECIAL_CHR);
 223
 224         if (rc)
 225                 goto out;
 226
 227         if (tcon->unix_ext)
 228                 rc = cifs_get_inode_info_unix(&inode, full_path, inode->i_sb,
 229                                               xid);
 230         else
 231                 rc = cifs_get_inode_info(&inode, full_path, buf, inode->i_sb,
 232                                          xid, pnetfid);
 233
 234 out:
 235         kfree(buf);
 236         return rc;
 237 }
 238
 239 struct cifsFileInfo *
 240 cifs_new_fileinfo(__u16 fileHandle, struct file *file,
 241                   struct tcon_link *tlink, __u32 oplock)
 242 {
 243         struct dentry *dentry = file->f_path.dentry;
 244         struct inode *inode = dentry->d_inode;
 245         struct cifsInodeInfo *pCifsInode = CIFS_I(inode);
 246         struct cifsFileInfo *pCifsFile;
 247
 248         pCifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 249         if (pCifsFile == NULL)
 250                 return pCifsFile;
 251
 252         pCifsFile->count = 1;
 253         pCifsFile->netfid = fileHandle;
 254         pCifsFile->pid = current->tgid;
 255         pCifsFile->uid = current_fsuid();
 256         pCifsFile->dentry = dget(dentry);
 257         pCifsFile->f_flags = file->f_flags;
 258         pCifsFile->invalidHandle = false;
 259         pCifsFile->tlink = cifs_get_tlink(tlink);
 260         mutex_init(&pCifsFile->fh_mutex);
 261         mutex_init(&pCifsFile->lock_mutex);
 262         INIT_LIST_HEAD(&pCifsFile->llist);
 263         INIT_WORK(&pCifsFile->oplock_break, cifs_oplock_break);
 264
 265         spin_lock(&cifs_file_list_lock);
 266         list_add(&pCifsFile->tlist, &(tlink_tcon(tlink)->openFileList));
 267         /* if readable file instance put first in list*/
 268         if (file->f_mode & FMODE_READ)
 269                 list_add(&pCifsFile->flist, &pCifsInode->openFileList);
 270         else
 271                 list_add_tail(&pCifsFile->flist, &pCifsInode->openFileList);
 272         spin_unlock(&cifs_file_list_lock);
 273
 274         cifs_set_oplock_level(pCifsInode, oplock);
 275
 276         file->private_data = pCifsFile;
 277         return pCifsFile;
 278 }
 279
 280 /*
 281  * Release a reference on the file private data. This may involve closing
 282  * the filehandle out on the server. Must be called without holding
 283  * cifs_file_list_lock.
 284  */
 285 void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
 286 {
 287         struct inode *inode = cifs_file->dentry->d_inode;
 288         struct cifsTconInfo *tcon = tlink_tcon(cifs_file->tlink);
 289         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 290         struct cifsLockInfo *li, *tmp;
 291
 292         spin_lock(&cifs_file_list_lock);
 293         if (--cifs_file->count > 0) {
 294                 spin_unlock(&cifs_file_list_lock);
 295                 return;
 296         }
 297
 298         /* remove it from the lists */
 299         list_del(&cifs_file->flist);
 300         list_del(&cifs_file->tlist);
 301
 302         if (list_empty(&cifsi->openFileList)) {
 303                 cFYI(1, "closing last open instance for inode %p",
 304                         cifs_file->dentry->d_inode);
 305                 cifs_set_oplock_level(cifsi, 0);
 306         }
 307         spin_unlock(&cifs_file_list_lock);
 308
 309         if (!tcon->need_reconnect && !cifs_file->invalidHandle) {
 310                 int xid, rc;
 311
 312                 xid = GetXid();
 313                 rc = CIFSSMBClose(xid, tcon, cifs_file->netfid);
 314                 FreeXid(xid);
 315         }
 316
 317         /* Delete any outstanding lock records. We'll lose them when the file
 318          * is closed anyway.
 319          */
 320         mutex_lock(&cifs_file->lock_mutex);
 321         list_for_each_entry_safe(li, tmp, &cifs_file->llist, llist) {
 322                 list_del(&li->llist);
 323                 kfree(li);
 324         }
 325         mutex_unlock(&cifs_file->lock_mutex);
 326
 327         cifs_put_tlink(cifs_file->tlink);
 328         dput(cifs_file->dentry);
 329         kfree(cifs_file);
 330 }
 331
 332 int cifs_open(struct inode *inode, struct file *file)
 333 {
 334         int rc = -EACCES;
 335         int xid;
 336         __u32 oplock;
 337         struct cifs_sb_info *cifs_sb;
 338         struct cifsTconInfo *tcon;
 339         struct tcon_link *tlink;
 340         struct cifsFileInfo *pCifsFile = NULL;
 341         struct cifsInodeInfo *pCifsInode;
 342         char *full_path = NULL;
 343         bool posix_open_ok = false;
 344         __u16 netfid;
 345
 346         xid = GetXid();
 347
 348         cifs_sb = CIFS_SB(inode->i_sb);
 349         tlink = cifs_sb_tlink(cifs_sb);
 350         if (IS_ERR(tlink)) {
 351                 FreeXid(xid);
 352                 return PTR_ERR(tlink);
 353         }
 354         tcon = tlink_tcon(tlink);
 355
 356         pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
 357
 358         full_path = build_path_from_dentry(file->f_path.dentry);
 359         if (full_path == NULL) {
 360                 rc = -ENOMEM;
 361                 goto out;
 362         }
 363
 364         cFYI(1, "inode = 0x%p file flags are 0x%x for %s",
 365                  inode, file->f_flags, full_path);
 366
 367         if (oplockEnabled)
 368                 oplock = REQ_OPLOCK;
 369         else
 370                 oplock = 0;
 371
 372         if (!tcon->broken_posix_open && tcon->unix_ext &&
 373             (tcon->ses->capabilities & CAP_UNIX) &&
 374             (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 375                         le64_to_cpu(tcon->fsUnixInfo.Capability))) {
 376                 /* can not refresh inode info since size could be stale */
 377                 rc = cifs_posix_open(full_path, &inode, inode->i_sb,
 378                                 cifs_sb->mnt_file_mode /* ignored */,
 379                                 file->f_flags, &oplock, &netfid, xid);
 380                 if (rc == 0) {
 381                         cFYI(1, "posix open succeeded");
 382                         posix_open_ok = true;
 383                 } else if ((rc == -EINVAL) || (rc == -EOPNOTSUPP)) {
 384                         if (tcon->ses->serverNOS)
 385                                 cERROR(1, "server %s of type %s returned"
 386                                            " unexpected error on SMB posix open"
 387                                            ", disabling posix open support."
 388                                            " Check if server update available.",
 389                                            tcon->ses->serverName,
 390                                            tcon->ses->serverNOS);
 391                         tcon->broken_posix_open = true;
 392                 } else if ((rc != -EIO) && (rc != -EREMOTE) &&
 393                          (rc != -EOPNOTSUPP)) /* path not found or net err */
 394                         goto out;
 395                 /* else fallthrough to retry open the old way on network i/o
 396                    or DFS errors */
 397         }
 398
 399         if (!posix_open_ok) {
 400                 rc = cifs_nt_open(full_path, inode, cifs_sb, tcon,
 401                                   file->f_flags, &oplock, &netfid, xid);
 402                 if (rc)
 403                         goto out;
 404         }
 405
 406         pCifsFile = cifs_new_fileinfo(netfid, file, tlink, oplock);
 407         if (pCifsFile == NULL) {
 408                 CIFSSMBClose(xid, tcon, netfid);
 409                 rc = -ENOMEM;
 410                 goto out;
 411         }
 412
 413         cifs_fscache_set_inode_cookie(inode, file);
 414
 415         if ((oplock & CIFS_CREATE_ACTION) && !posix_open_ok && tcon->unix_ext) {
 416                 /* time to set mode which we can not set earlier due to
 417                    problems creating new read-only files */
 418                 struct cifs_unix_set_info_args args = {
 419                         .mode   = inode->i_mode,
 420                         .uid    = NO_CHANGE_64,
 421                         .gid    = NO_CHANGE_64,
 422                         .ctime  = NO_CHANGE_64,
 423                         .atime  = NO_CHANGE_64,
 424                         .mtime  = NO_CHANGE_64,
 425                         .device = 0,
 426                 };
 427                 CIFSSMBUnixSetFileInfo(xid, tcon, &args, netfid,
 428                                         pCifsFile->pid);
 429         }
 430
 431 out:
 432         kfree(full_path);
 433         FreeXid(xid);
 434         cifs_put_tlink(tlink);
 435         return rc;
 436 }
 437
 438 /* Try to reacquire byte range locks that were released when session */
 439 /* to server was lost */
 440 static int cifs_relock_file(struct cifsFileInfo *cifsFile)
 441 {
 442         int rc = 0;
 443
 444 /* BB list all locks open on this file and relock */
 445
 446         return rc;
 447 }
 448
 449 static int cifs_reopen_file(struct cifsFileInfo *pCifsFile, bool can_flush)
 450 {
 451         int rc = -EACCES;
 452         int xid;
 453         __u32 oplock;
 454         struct cifs_sb_info *cifs_sb;
 455         struct cifsTconInfo *tcon;
 456         struct cifsInodeInfo *pCifsInode;
 457         struct inode *inode;
 458         char *full_path = NULL;
 459         int desiredAccess;
 460         int disposition = FILE_OPEN;
 461         __u16 netfid;
 462
 463         xid = GetXid();
 464         mutex_lock(&pCifsFile->fh_mutex);
 465         if (!pCifsFile->invalidHandle) {
 466                 mutex_unlock(&pCifsFile->fh_mutex);
 467                 rc = 0;
 468                 FreeXid(xid);
 469                 return rc;
 470         }
 471
 472         inode = pCifsFile->dentry->d_inode;
 473         cifs_sb = CIFS_SB(inode->i_sb);
 474         tcon = tlink_tcon(pCifsFile->tlink);
 475
 476 /* can not grab rename sem here because various ops, including
 477    those that already have the rename sem can end up causing writepage
 478    to get called and if the server was down that means we end up here,
 479    and we can never tell if the caller already has the rename_sem */
 480         full_path = build_path_from_dentry(pCifsFile->dentry);
 481         if (full_path == NULL) {
 482                 rc = -ENOMEM;
 483                 mutex_unlock(&pCifsFile->fh_mutex);
 484                 FreeXid(xid);
 485                 return rc;
 486         }
 487
 488         cFYI(1, "inode = 0x%p file flags 0x%x for %s",
 489                  inode, pCifsFile->f_flags, full_path);
 490
 491         if (oplockEnabled)
 492                 oplock = REQ_OPLOCK;
 493         else
 494                 oplock = 0;
 495
 496         if (tcon->unix_ext && (tcon->ses->capabilities & CAP_UNIX) &&
 497             (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 498                         le64_to_cpu(tcon->fsUnixInfo.Capability))) {
 499
 500                 /*
 501                  * O_CREAT, O_EXCL and O_TRUNC already had their effect on the
 502                  * original open. Must mask them off for a reopen.
 503                  */
 504                 unsigned int oflags = pCifsFile->f_flags &
 505                                                 ~(O_CREAT | O_EXCL | O_TRUNC);
 506
 507                 rc = cifs_posix_open(full_path, NULL, inode->i_sb,
 508                                 cifs_sb->mnt_file_mode /* ignored */,
 509                                 oflags, &oplock, &netfid, xid);
 510                 if (rc == 0) {
 511                         cFYI(1, "posix reopen succeeded");
 512                         goto reopen_success;
 513                 }
 514                 /* fallthrough to retry open the old way on errors, especially
 515                    in the reconnect path it is important to retry hard */
 516         }
 517
 518         desiredAccess = cifs_convert_flags(pCifsFile->f_flags);
 519
 520         /* Can not refresh inode by passing in file_info buf to be returned
 521            by SMBOpen and then calling get_inode_info with returned buf
 522            since file might have write behind data that needs to be flushed
 523            and server version of file size can be stale. If we knew for sure
 524            that inode was not dirty locally we could do this */
 525
 526         rc = CIFSSMBOpen(xid, tcon, full_path, disposition, desiredAccess,
 527                          CREATE_NOT_DIR, &netfid, &oplock, NULL,
 528                          cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
 529                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 530         if (rc) {
 531                 mutex_unlock(&pCifsFile->fh_mutex);
 532                 cFYI(1, "cifs_open returned 0x%x", rc);
 533                 cFYI(1, "oplock: %d", oplock);
 534                 goto reopen_error_exit;
 535         }
 536
 537 reopen_success:
 538         pCifsFile->netfid = netfid;
 539         pCifsFile->invalidHandle = false;
 540         mutex_unlock(&pCifsFile->fh_mutex);
 541         pCifsInode = CIFS_I(inode);
 542
 543         if (can_flush) {
 544                 rc = filemap_write_and_wait(inode->i_mapping);
 545                 mapping_set_error(inode->i_mapping, rc);
 546
 547                 if (tcon->unix_ext)
 548                         rc = cifs_get_inode_info_unix(&inode,
 549                                 full_path, inode->i_sb, xid);
 550                 else
 551                         rc = cifs_get_inode_info(&inode,
 552                                 full_path, NULL, inode->i_sb,
 553                                 xid, NULL);
 554         } /* else we are writing out data to server already
 555              and could deadlock if we tried to flush data, and
 556              since we do not know if we have data that would
 557              invalidate the current end of file on the server
 558              we can not go to the server to get the new inod
 559              info */
 560
 561         cifs_set_oplock_level(pCifsInode, oplock);
 562
 563         cifs_relock_file(pCifsFile);
 564
 565 reopen_error_exit:
 566         kfree(full_path);
 567         FreeXid(xid);
 568         return rc;
 569 }
 570
 571 int cifs_close(struct inode *inode, struct file *file)
 572 {
 573         cifsFileInfo_put(file->private_data);
 574         file->private_data = NULL;
 575
 576         /* return code from the ->release op is always ignored */
 577         return 0;
 578 }
 579
 580 int cifs_closedir(struct inode *inode, struct file *file)
 581 {
 582         int rc = 0;
 583         int xid;
 584         struct cifsFileInfo *pCFileStruct = file->private_data;
 585         char *ptmp;
 586
 587         cFYI(1, "Closedir inode = 0x%p", inode);
 588
 589         xid = GetXid();
 590
 591         if (pCFileStruct) {
 592                 struct cifsTconInfo *pTcon = tlink_tcon(pCFileStruct->tlink);
 593
 594                 cFYI(1, "Freeing private data in close dir");
 595                 spin_lock(&cifs_file_list_lock);
 596                 if (!pCFileStruct->srch_inf.endOfSearch &&
 597                     !pCFileStruct->invalidHandle) {
 598                         pCFileStruct->invalidHandle = true;
 599                         spin_unlock(&cifs_file_list_lock);
 600                         rc = CIFSFindClose(xid, pTcon, pCFileStruct->netfid);
 601                         cFYI(1, "Closing uncompleted readdir with rc %d",
 602                                  rc);
 603                         /* not much we can do if it fails anyway, ignore rc */
 604                         rc = 0;
 605                 } else
 606                         spin_unlock(&cifs_file_list_lock);
 607                 ptmp = pCFileStruct->srch_inf.ntwrk_buf_start;
 608                 if (ptmp) {
 609                         cFYI(1, "closedir free smb buf in srch struct");
 610                         pCFileStruct->srch_inf.ntwrk_buf_start = NULL;
 611                         if (pCFileStruct->srch_inf.smallBuf)
 612                                 cifs_small_buf_release(ptmp);
 613                         else
 614                                 cifs_buf_release(ptmp);
 615                 }
 616                 cifs_put_tlink(pCFileStruct->tlink);
 617                 kfree(file->private_data);
 618                 file->private_data = NULL;
 619         }
 620         /* BB can we lock the filestruct while this is going on? */
 621         FreeXid(xid);
 622         return rc;
 623 }
 624
 625 static int store_file_lock(struct cifsFileInfo *fid, __u64 len,
 626                                 __u64 offset, __u8 lockType)
 627 {
 628         struct cifsLockInfo *li =
 629                 kmalloc(sizeof(struct cifsLockInfo), GFP_KERNEL);
 630         if (li == NULL)
 631                 return -ENOMEM;
 632         li->offset = offset;
 633         li->length = len;
 634         li->type = lockType;
 635         mutex_lock(&fid->lock_mutex);
 636         list_add(&li->llist, &fid->llist);
 637         mutex_unlock(&fid->lock_mutex);
 638         return 0;
 639 }
 640
 641 int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
 642 {
 643         int rc, xid;
 644         __u32 numLock = 0;
 645         __u32 numUnlock = 0;
 646         __u64 length;
 647         bool wait_flag = false;
 648         struct cifs_sb_info *cifs_sb;
 649         struct cifsTconInfo *tcon;
 650         __u16 netfid;
 651         __u8 lockType = LOCKING_ANDX_LARGE_FILES;
 652         bool posix_locking = 0;
 653
 654         length = 1 + pfLock->fl_end - pfLock->fl_start;
 655         rc = -EACCES;
 656         xid = GetXid();
 657
 658         cFYI(1, "Lock parm: 0x%x flockflags: "
 659                  "0x%x flocktype: 0x%x start: %lld end: %lld",
 660                 cmd, pfLock->fl_flags, pfLock->fl_type, pfLock->fl_start,
 661                 pfLock->fl_end);
 662
 663         if (pfLock->fl_flags & FL_POSIX)
 664                 cFYI(1, "Posix");
 665         if (pfLock->fl_flags & FL_FLOCK)
 666                 cFYI(1, "Flock");
 667         if (pfLock->fl_flags & FL_SLEEP) {
 668                 cFYI(1, "Blocking lock");
 669                 wait_flag = true;
 670         }
 671         if (pfLock->fl_flags & FL_ACCESS)
 672                 cFYI(1, "Process suspended by mandatory locking - "
 673                          "not implemented yet");
 674         if (pfLock->fl_flags & FL_LEASE)
 675                 cFYI(1, "Lease on file - not implemented yet");
 676         if (pfLock->fl_flags &
 677             (~(FL_POSIX | FL_FLOCK | FL_SLEEP | FL_ACCESS | FL_LEASE)))
 678                 cFYI(1, "Unknown lock flags 0x%x", pfLock->fl_flags);
 679
 680         if (pfLock->fl_type == F_WRLCK) {
 681                 cFYI(1, "F_WRLCK ");
 682                 numLock = 1;
 683         } else if (pfLock->fl_type == F_UNLCK) {
 684                 cFYI(1, "F_UNLCK");
 685                 numUnlock = 1;
 686                 /* Check if unlock includes more than
 687                 one lock range */
 688         } else if (pfLock->fl_type == F_RDLCK) {
 689                 cFYI(1, "F_RDLCK");
 690                 lockType |= LOCKING_ANDX_SHARED_LOCK;
 691                 numLock = 1;
 692         } else if (pfLock->fl_type == F_EXLCK) {
 693                 cFYI(1, "F_EXLCK");
 694                 numLock = 1;
 695         } else if (pfLock->fl_type == F_SHLCK) {
 696                 cFYI(1, "F_SHLCK");
 697                 lockType |= LOCKING_ANDX_SHARED_LOCK;
 698                 numLock = 1;
 699         } else
 700                 cFYI(1, "Unknown type of lock");
 701
 702         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 703         tcon = tlink_tcon(((struct cifsFileInfo *)file->private_data)->tlink);
 704         netfid = ((struct cifsFileInfo *)file->private_data)->netfid;
 705
 706         if ((tcon->ses->capabilities & CAP_UNIX) &&
 707             (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
 708             ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
 709                 posix_locking = 1;
 710         /* BB add code here to normalize offset and length to
 711         account for negative length which we can not accept over the
 712         wire */
 713         if (IS_GETLK(cmd)) {
 714                 if (posix_locking) {
 715                         int posix_lock_type;
 716                         if (lockType & LOCKING_ANDX_SHARED_LOCK)
 717                                 posix_lock_type = CIFS_RDLCK;
 718                         else
 719                                 posix_lock_type = CIFS_WRLCK;
 720                         rc = CIFSSMBPosixLock(xid, tcon, netfid, 1 /* get */,
 721                                         length, pfLock,
 722                                         posix_lock_type, wait_flag);
 723                         FreeXid(xid);
 724                         return rc;
 725                 }
 726
 727                 /* BB we could chain these into one lock request BB */
 728                 rc = CIFSSMBLock(xid, tcon, netfid, length, pfLock->fl_start,
 729                                  0, 1, lockType, 0 /* wait flag */ );
 730                 if (rc == 0) {
 731                         rc = CIFSSMBLock(xid, tcon, netfid, length,
 732                                          pfLock->fl_start, 1 /* numUnlock */ ,
 733                                          0 /* numLock */ , lockType,
 734                                          0 /* wait flag */ );
 735                         pfLock->fl_type = F_UNLCK;
 736                         if (rc != 0)
 737                                 cERROR(1, "Error unlocking previously locked "
 738                                            "range %d during test of lock", rc);
 739                         rc = 0;
 740
 741                 } else {
 742                         /* if rc == ERR_SHARING_VIOLATION ? */
 743                         rc = 0;
 744
 745                         if (lockType & LOCKING_ANDX_SHARED_LOCK) {
 746                                 pfLock->fl_type = F_WRLCK;
 747                         } else {
 748                                 rc = CIFSSMBLock(xid, tcon, netfid, length,
 749                                         pfLock->fl_start, 0, 1,
 750                                         lockType | LOCKING_ANDX_SHARED_LOCK,
 751                                         0 /* wait flag */);
 752                                 if (rc == 0) {
 753                                         rc = CIFSSMBLock(xid, tcon, netfid,
 754                                                 length, pfLock->fl_start, 1, 0,
 755                                                 lockType |
 756                                                 LOCKING_ANDX_SHARED_LOCK,
 757                                                 0 /* wait flag */);
 758                                         pfLock->fl_type = F_RDLCK;
 759                                         if (rc != 0)
 760                                                 cERROR(1, "Error unlocking "
 761                                                 "previously locked range %d "
 762                                                 "during test of lock", rc);
 763                                         rc = 0;
 764                                 } else {
 765                                         pfLock->fl_type = F_WRLCK;
 766                                         rc = 0;
 767                                 }
 768                         }
 769                 }
 770
 771                 FreeXid(xid);
 772                 return rc;
 773         }
 774
 775         if (!numLock && !numUnlock) {
 776                 /* if no lock or unlock then nothing
 777                 to do since we do not know what it is */
 778                 FreeXid(xid);
 779                 return -EOPNOTSUPP;
 780         }
 781
 782         if (posix_locking) {
 783                 int posix_lock_type;
 784                 if (lockType & LOCKING_ANDX_SHARED_LOCK)
 785                         posix_lock_type = CIFS_RDLCK;
 786                 else
 787                         posix_lock_type = CIFS_WRLCK;
 788
 789                 if (numUnlock == 1)
 790                         posix_lock_type = CIFS_UNLCK;
 791
 792                 rc = CIFSSMBPosixLock(xid, tcon, netfid, 0 /* set */,
 793                                       length, pfLock,
 794                                       posix_lock_type, wait_flag);
 795         } else {
 796                 struct cifsFileInfo *fid = file->private_data;
 797
 798                 if (numLock) {
 799                         rc = CIFSSMBLock(xid, tcon, netfid, length,
 800                                         pfLock->fl_start,
 801                                         0, numLock, lockType, wait_flag);
 802
 803                         if (rc == 0) {
 804                                 /* For Windows locks we must store them. */
 805                                 rc = store_file_lock(fid, length,
 806                                                 pfLock->fl_start, lockType);
 807                         }
 808                 } else if (numUnlock) {
 809                         /* For each stored lock that this unlock overlaps
 810                            completely, unlock it. */
 811                         int stored_rc = 0;
 812                         struct cifsLockInfo *li, *tmp;
 813
 814                         rc = 0;
 815                         mutex_lock(&fid->lock_mutex);
 816                         list_for_each_entry_safe(li, tmp, &fid->llist, llist) {
 817                                 if (pfLock->fl_start <= li->offset &&
 818                                                 (pfLock->fl_start + length) >=
 819                                                 (li->offset + li->length)) {
 820                                         stored_rc = CIFSSMBLock(xid, tcon,
 821                                                         netfid,
 822                                                         li->length, li->offset,
 823                                                         1, 0, li->type, false);
 824                                         if (stored_rc)
 825                                                 rc = stored_rc;
 826                                         else {
 827                                                 list_del(&li->llist);
 828                                                 kfree(li);
 829                                         }
 830                                 }
 831                         }
 832                         mutex_unlock(&fid->lock_mutex);
 833                 }
 834         }
 835
 836         if (pfLock->fl_flags & FL_POSIX)
 837                 posix_lock_file_wait(file, pfLock);
 838         FreeXid(xid);
 839         return rc;
 840 }
 841
 842 /*
 843  * Set the timeout on write requests past EOF. For some servers (Windows)
 844  * these calls can be very long.
 845  *
 846  * If we're writing >10M past the EOF we give a 180s timeout. Anything less
 847  * than that gets a 45s timeout. Writes not past EOF get 15s timeouts.
 848  * The 10M cutoff is totally arbitrary. A better scheme for this would be
 849  * welcome if someone wants to suggest one.
 850  *
 851  * We may be able to do a better job with this if there were some way to
 852  * declare that a file should be sparse.
 853  */
 854 static int
 855 cifs_write_timeout(struct cifsInodeInfo *cifsi, loff_t offset)
 856 {
 857         if (offset <= cifsi->server_eof)
 858                 return CIFS_STD_OP;
 859         else if (offset > (cifsi->server_eof + (10 * 1024 * 1024)))
 860                 return CIFS_VLONG_OP;
 861         else
 862                 return CIFS_LONG_OP;
 863 }
 864
 865 /* update the file size (if needed) after a write */
 866 static void
 867 cifs_update_eof(struct cifsInodeInfo *cifsi, loff_t offset,
 868                       unsigned int bytes_written)
 869 {
 870         loff_t end_of_write = offset + bytes_written;
 871
 872         if (end_of_write > cifsi->server_eof)
 873                 cifsi->server_eof = end_of_write;
 874 }
 875
 876 ssize_t cifs_user_write(struct file *file, const char __user *write_data,
 877         size_t write_size, loff_t *poffset)
 878 {
 879         struct inode *inode = file->f_path.dentry->d_inode;
 880         int rc = 0;
 881         unsigned int bytes_written = 0;
 882         unsigned int total_written;
 883         struct cifs_sb_info *cifs_sb;
 884         struct cifsTconInfo *pTcon;
 885         int xid, long_op;
 886         struct cifsFileInfo *open_file;
 887         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 888
 889         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 890
 891         /* cFYI(1, " write %d bytes to offset %lld of %s", write_size,
 892            *poffset, file->f_path.dentry->d_name.name); */
 893
 894         if (file->private_data == NULL)
 895                 return -EBADF;
 896
 897         open_file = file->private_data;
 898         pTcon = tlink_tcon(open_file->tlink);
 899
 900         rc = generic_write_checks(file, poffset, &write_size, 0);
 901         if (rc)
 902                 return rc;
 903
 904         xid = GetXid();
 905
 906         long_op = cifs_write_timeout(cifsi, *poffset);
 907         for (total_written = 0; write_size > total_written;
 908              total_written += bytes_written) {
 909                 rc = -EAGAIN;
 910                 while (rc == -EAGAIN) {
 911                         if (file->private_data == NULL) {
 912                                 /* file has been closed on us */
 913                                 FreeXid(xid);
 914                         /* if we have gotten here we have written some data
 915                            and blocked, and the file has been freed on us while
 916                            we blocked so return what we managed to write */
 917                                 return total_written;
 918                         }
 919                         if (open_file->invalidHandle) {
 920                                 /* we could deadlock if we called
 921                                    filemap_fdatawait from here so tell
 922                                    reopen_file not to flush data to server
 923                                    now */
 924                                 rc = cifs_reopen_file(open_file, false);
 925                                 if (rc != 0)
 926                                         break;
 927                         }
 928
 929                         rc = CIFSSMBWrite(xid, pTcon,
 930                                 open_file->netfid,
 931                                 min_t(const int, cifs_sb->wsize,
 932                                       write_size - total_written),
 933                                 *poffset, &bytes_written,
 934                                 NULL, write_data + total_written, long_op);
 935                 }
 936                 if (rc || (bytes_written == 0)) {
 937                         if (total_written)
 938                                 break;
 939                         else {
 940                                 FreeXid(xid);
 941                                 return rc;
 942                         }
 943                 } else {
 944                         cifs_update_eof(cifsi, *poffset, bytes_written);
 945                         *poffset += bytes_written;
 946                 }
 947                 long_op = CIFS_STD_OP; /* subsequent writes fast -
 948                                     15 seconds is plenty */
 949         }
 950
 951         cifs_stats_bytes_written(pTcon, total_written);
 952
 953 /* Do not update local mtime - server will set its actual value on write
 954  *      inode->i_ctime = inode->i_mtime =
 955  *              current_fs_time(inode->i_sb);*/
 956         if (total_written > 0) {
 957                 spin_lock(&inode->i_lock);
 958                 if (*poffset > inode->i_size)
 959                         i_size_write(inode, *poffset);
 960                 spin_unlock(&inode->i_lock);
 961         }
 962         mark_inode_dirty_sync(inode);
 963
 964         FreeXid(xid);
 965         return total_written;
 966 }
 967
 968 static ssize_t cifs_write(struct cifsFileInfo *open_file,
 969                           const char *write_data, size_t write_size,
 970                           loff_t *poffset)
 971 {
 972         int rc = 0;
 973         unsigned int bytes_written = 0;
 974         unsigned int total_written;
 975         struct cifs_sb_info *cifs_sb;
 976         struct cifsTconInfo *pTcon;
 977         int xid, long_op;
 978         struct dentry *dentry = open_file->dentry;
 979         struct cifsInodeInfo *cifsi = CIFS_I(dentry->d_inode);
 980
 981         cifs_sb = CIFS_SB(dentry->d_sb);
 982
 983         cFYI(1, "write %zd bytes to offset %lld of %s", write_size,
 984            *poffset, dentry->d_name.name);
 985
 986         pTcon = tlink_tcon(open_file->tlink);
 987
 988         xid = GetXid();
 989
 990         long_op = cifs_write_timeout(cifsi, *poffset);
 991         for (total_written = 0; write_size > total_written;
 992              total_written += bytes_written) {
 993                 rc = -EAGAIN;
 994                 while (rc == -EAGAIN) {
 995                         if (open_file->invalidHandle) {
 996                                 /* we could deadlock if we called
 997                                    filemap_fdatawait from here so tell
 998                                    reopen_file not to flush data to
 999                                    server now */
1000                                 rc = cifs_reopen_file(open_file, false);
1001                                 if (rc != 0)
1002                                         break;
1003                         }
1004                         if (experimEnabled || (pTcon->ses->server &&
1005                                 ((pTcon->ses->server->secMode &
1006                                 (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
1007                                 == 0))) {
1008                                 struct kvec iov[2];
1009                                 unsigned int len;
1010
1011                                 len = min((size_t)cifs_sb->wsize,
1012                                           write_size - total_written);
1013                                 /* iov[0] is reserved for smb header */
1014                                 iov[1].iov_base = (char *)write_data +
1015                                                   total_written;
1016                                 iov[1].iov_len = len;
1017                                 rc = CIFSSMBWrite2(xid, pTcon,
1018                                                 open_file->netfid, len,
1019                                                 *poffset, &bytes_written,
1020                                                 iov, 1, long_op);
1021                         } else
1022                                 rc = CIFSSMBWrite(xid, pTcon,
1023                                          open_file->netfid,
1024                                          min_t(const int, cifs_sb->wsize,
1025                                                write_size - total_written),
1026                                          *poffset, &bytes_written,
1027                                          write_data + total_written,
1028                                          NULL, long_op);
1029                 }
1030                 if (rc || (bytes_written == 0)) {
1031                         if (total_written)
1032                                 break;
1033                         else {
1034                                 FreeXid(xid);
1035                                 return rc;
1036                         }
1037                 } else {
1038                         cifs_update_eof(cifsi, *poffset, bytes_written);
1039                         *poffset += bytes_written;
1040                 }
1041                 long_op = CIFS_STD_OP; /* subsequent writes fast -
1042                                     15 seconds is plenty */
1043         }
1044
1045         cifs_stats_bytes_written(pTcon, total_written);
1046
1047         if (total_written > 0) {
1048                 spin_lock(&dentry->d_inode->i_lock);
1049                 if (*poffset > dentry->d_inode->i_size)
1050                         i_size_write(dentry->d_inode, *poffset);
1051                 spin_unlock(&dentry->d_inode->i_lock);
1052         }
1053         mark_inode_dirty_sync(dentry->d_inode);
1054         FreeXid(xid);
1055         return total_written;
1056 }
1057
1058 struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode,
1059                                         bool fsuid_only)
1060 {
1061         struct cifsFileInfo *open_file = NULL;
1062         struct cifs_sb_info *cifs_sb = CIFS_SB(cifs_inode->vfs_inode.i_sb);
1063
1064         /* only filter by fsuid on multiuser mounts */
1065         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
1066                 fsuid_only = false;
1067
1068         spin_lock(&cifs_file_list_lock);
1069         /* we could simply get the first_list_entry since write-only entries
1070            are always at the end of the list but since the first entry might
1071            have a close pending, we go through the whole list */
1072         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
1073                 if (fsuid_only && open_file->uid != current_fsuid())
1074                         continue;
1075                 if (OPEN_FMODE(open_file->f_flags) & FMODE_READ) {
1076                         if (!open_file->invalidHandle) {
1077                                 /* found a good file */
1078                                 /* lock it so it will not be closed on us */
1079                                 cifsFileInfo_get(open_file);
1080                                 spin_unlock(&cifs_file_list_lock);
1081                                 return open_file;
1082                         } /* else might as well continue, and look for
1083                              another, or simply have the caller reopen it
1084                              again rather than trying to fix this handle */
1085                 } else /* write only file */
1086                         break; /* write only files are last so must be done */
1087         }
1088         spin_unlock(&cifs_file_list_lock);
1089         return NULL;
1090 }
1091
1092 struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode,
1093                                         bool fsuid_only)
1094 {
1095         struct cifsFileInfo *open_file;
1096         struct cifs_sb_info *cifs_sb;
1097         bool any_available = false;
1098         int rc;
1099
1100         /* Having a null inode here (because mapping->host was set to zero by
1101         the VFS or MM) should not happen but we had reports of on oops (due to
1102         it being zero) during stress testcases so we need to check for it */
1103
1104         if (cifs_inode == NULL) {
1105                 cERROR(1, "Null inode passed to cifs_writeable_file");
1106                 dump_stack();
1107                 return NULL;
1108         }
1109
1110         cifs_sb = CIFS_SB(cifs_inode->vfs_inode.i_sb);
1111
1112         /* only filter by fsuid on multiuser mounts */
1113         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
1114                 fsuid_only = false;
1115
1116         spin_lock(&cifs_file_list_lock);
1117 refind_writable:
1118         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
1119                 if (!any_available && open_file->pid != current->tgid)
1120                         continue;
1121                 if (fsuid_only && open_file->uid != current_fsuid())
1122                         continue;
1123                 if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
1124                         cifsFileInfo_get(open_file);
1125
1126                         if (!open_file->invalidHandle) {
1127                                 /* found a good writable file */
1128                                 spin_unlock(&cifs_file_list_lock);
1129                                 return open_file;
1130                         }
1131
1132                         spin_unlock(&cifs_file_list_lock);
1133
1134                         /* Had to unlock since following call can block */
1135                         rc = cifs_reopen_file(open_file, false);
1136                         if (!rc)
1137                                 return open_file;
1138
1139                         /* if it fails, try another handle if possible */
1140                         cFYI(1, "wp failed on reopen file");
1141                         cifsFileInfo_put(open_file);
1142
1143                         spin_lock(&cifs_file_list_lock);
1144
1145                         /* else we simply continue to the next entry. Thus
1146                            we do not loop on reopen errors.  If we
1147                            can not reopen the file, for example if we
1148                            reconnected to a server with another client
1149                            racing to delete or lock the file we would not
1150                            make progress if we restarted before the beginning
1151                            of the loop here. */
1152                 }
1153         }
1154         /* couldn't find useable FH with same pid, try any available */
1155         if (!any_available) {
1156                 any_available = true;
1157                 goto refind_writable;
1158         }
1159         spin_unlock(&cifs_file_list_lock);
1160         return NULL;
1161 }
1162
1163 static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
1164 {
1165         struct address_space *mapping = page->mapping;
1166         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1167         char *write_data;
1168         int rc = -EFAULT;
1169         int bytes_written = 0;
1170         struct cifs_sb_info *cifs_sb;
1171         struct inode *inode;
1172         struct cifsFileInfo *open_file;
1173
1174         if (!mapping || !mapping->host)
1175                 return -EFAULT;
1176
1177         inode = page->mapping->host;
1178         cifs_sb = CIFS_SB(inode->i_sb);
1179
1180         offset += (loff_t)from;
1181         write_data = kmap(page);
1182         write_data += from;
1183
1184         if ((to > PAGE_CACHE_SIZE) || (from > to)) {
1185                 kunmap(page);
1186                 return -EIO;
1187         }
1188
1189         /* racing with truncate? */
1190         if (offset > mapping->host->i_size) {
1191                 kunmap(page);
1192                 return 0; /* don't care */
1193         }
1194
1195         /* check to make sure that we are not extending the file */
1196         if (mapping->host->i_size - offset < (loff_t)to)
1197                 to = (unsigned)(mapping->host->i_size - offset);
1198
1199         open_file = find_writable_file(CIFS_I(mapping->host), false);
1200         if (open_file) {
1201                 bytes_written = cifs_write(open_file, write_data,
1202                                            to - from, &offset);
1203                 cifsFileInfo_put(open_file);
1204                 /* Does mm or vfs already set times? */
1205                 inode->i_atime = inode->i_mtime = current_fs_time(inode->i_sb);
1206                 if ((bytes_written > 0) && (offset))
1207                         rc = 0;
1208                 else if (bytes_written < 0)
1209                         rc = bytes_written;
1210         } else {
1211                 cFYI(1, "No writeable filehandles for inode");
1212                 rc = -EIO;
1213         }
1214
1215         kunmap(page);
1216         return rc;
1217 }
1218
1219 static int cifs_writepages(struct address_space *mapping,
1220                            struct writeback_control *wbc)
1221 {
1222         unsigned int bytes_to_write;
1223         unsigned int bytes_written;
1224         struct cifs_sb_info *cifs_sb;
1225         int done = 0;
1226         pgoff_t end;
1227         pgoff_t index;
1228         int range_whole = 0;
1229         struct kvec *iov;
1230         int len;
1231         int n_iov = 0;
1232         pgoff_t next;
1233         int nr_pages;
1234         __u64 offset = 0;
1235         struct cifsFileInfo *open_file;
1236         struct cifsTconInfo *tcon;
1237         struct cifsInodeInfo *cifsi = CIFS_I(mapping->host);
1238         struct page *page;
1239         struct pagevec pvec;
1240         int rc = 0;
1241         int scanned = 0;
1242         int xid, long_op;
1243
1244         cifs_sb = CIFS_SB(mapping->host->i_sb);
1245
1246         /*
1247          * If wsize is smaller that the page cache size, default to writing
1248          * one page at a time via cifs_writepage
1249          */
1250         if (cifs_sb->wsize < PAGE_CACHE_SIZE)
1251                 return generic_writepages(mapping, wbc);
1252
1253         iov = kmalloc(32 * sizeof(struct kvec), GFP_KERNEL);
1254         if (iov == NULL)
1255                 return generic_writepages(mapping, wbc);
1256
1257         /*
1258          * if there's no open file, then this is likely to fail too,
1259          * but it'll at least handle the return. Maybe it should be
1260          * a BUG() instead?
1261          */
1262         open_file = find_writable_file(CIFS_I(mapping->host), false);
1263         if (!open_file) {
1264                 kfree(iov);
1265                 return generic_writepages(mapping, wbc);
1266         }
1267
1268         tcon = tlink_tcon(open_file->tlink);
1269         if (!experimEnabled && tcon->ses->server->secMode &
1270                         (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
1271                 cifsFileInfo_put(open_file);
1272                 kfree(iov);
1273                 return generic_writepages(mapping, wbc);
1274         }
1275         cifsFileInfo_put(open_file);
1276
1277         xid = GetXid();
1278
1279         pagevec_init(&pvec, 0);
1280         if (wbc->range_cyclic) {
1281                 index = mapping->writeback_index; /* Start from prev offset */
1282                 end = -1;
1283         } else {
1284                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
1285                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
1286                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
1287                         range_whole = 1;
1288                 scanned = 1;
1289         }
1290 retry:
1291         while (!done && (index <= end) &&
1292                (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
1293                         PAGECACHE_TAG_DIRTY,
1294                         min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1))) {
1295                 int first;
1296                 unsigned int i;
1297
1298                 first = -1;
1299                 next = 0;
1300                 n_iov = 0;
1301                 bytes_to_write = 0;
1302
1303                 for (i = 0; i < nr_pages; i++) {
1304                         page = pvec.pages[i];
1305                         /*
1306                          * At this point we hold neither mapping->tree_lock nor
1307                          * lock on the page itself: the page may be truncated or
1308                          * invalidated (changing page->mapping to NULL), or even
1309                          * swizzled back from swapper_space to tmpfs file
1310                          * mapping
1311                          */
1312
1313                         if (first < 0)
1314                                 lock_page(page);
1315                         else if (!trylock_page(page))
1316                                 break;
1317
1318                         if (unlikely(page->mapping != mapping)) {
1319                                 unlock_page(page);
1320                                 break;
1321                         }
1322
1323                         if (!wbc->range_cyclic && page->index > end) {
1324                                 done = 1;
1325                                 unlock_page(page);
1326                                 break;
1327                         }
1328
1329                         if (next && (page->index != next)) {
1330                                 /* Not next consecutive page */
1331                                 unlock_page(page);
1332                                 break;
1333                         }
1334
1335                         if (wbc->sync_mode != WB_SYNC_NONE)
1336                                 wait_on_page_writeback(page);
1337
1338                         if (PageWriteback(page) ||
1339                                         !clear_page_dirty_for_io(page)) {
1340                                 unlock_page(page);
1341                                 break;
1342                         }
1343
1344                         /*
1345                          * This actually clears the dirty bit in the radix tree.
1346                          * See cifs_writepage() for more commentary.
1347                          */
1348                         set_page_writeback(page);
1349
1350                         if (page_offset(page) >= mapping->host->i_size) {
1351                                 done = 1;
1352                                 unlock_page(page);
1353                                 end_page_writeback(page);
1354                                 break;
1355                         }
1356
1357                         /*
1358                          * BB can we get rid of this?  pages are held by pvec
1359                          */
1360                         page_cache_get(page);
1361
1362                         len = min(mapping->host->i_size - page_offset(page),
1363                                   (loff_t)PAGE_CACHE_SIZE);
1364
1365                         /* reserve iov[0] for the smb header */
1366                         n_iov++;
1367                         iov[n_iov].iov_base = kmap(page);
1368                         iov[n_iov].iov_len = len;
1369                         bytes_to_write += len;
1370
1371                         if (first < 0) {
1372                                 first = i;
1373                                 offset = page_offset(page);
1374                         }
1375                         next = page->index + 1;
1376                         if (bytes_to_write + PAGE_CACHE_SIZE > cifs_sb->wsize)
1377                                 break;
1378                 }
1379                 if (n_iov) {
1380                         open_file = find_writable_file(CIFS_I(mapping->host),
1381                                                         false);
1382                         if (!open_file) {
1383                                 cERROR(1, "No writable handles for inode");
1384                                 rc = -EBADF;
1385                         } else {
1386                                 long_op = cifs_write_timeout(cifsi, offset);
1387                                 rc = CIFSSMBWrite2(xid, tcon, open_file->netfid,
1388                                                    bytes_to_write, offset,
1389                                                    &bytes_written, iov, n_iov,
1390                                                    long_op);
1391                                 cifsFileInfo_put(open_file);
1392                                 cifs_update_eof(cifsi, offset, bytes_written);
1393                         }
1394
1395                         if (rc || bytes_written < bytes_to_write) {
1396                                 cERROR(1, "Write2 ret %d, wrote %d",
1397                                           rc, bytes_written);
1398                                 mapping_set_error(mapping, rc);
1399                         } else {
1400                                 cifs_stats_bytes_written(tcon, bytes_written);
1401                         }
1402
1403                         for (i = 0; i < n_iov; i++) {
1404                                 page = pvec.pages[first + i];
1405                                 /* Should we also set page error on
1406                                 success rc but too little data written? */
1407                                 /* BB investigate retry logic on temporary
1408                                 server crash cases and how recovery works
1409                                 when page marked as error */
1410                                 if (rc)
1411                                         SetPageError(page);
1412                                 kunmap(page);
1413                                 unlock_page(page);
1414                                 end_page_writeback(page);
1415                                 page_cache_release(page);
1416                         }
1417                         if ((wbc->nr_to_write -= n_iov) <= 0)
1418                                 done = 1;
1419                         index = next;
1420                 } else
1421                         /* Need to re-find the pages we skipped */
1422                         index = pvec.pages[0]->index + 1;
1423
1424                 pagevec_release(&pvec);
1425         }
1426         if (!scanned && !done) {
1427                 /*
1428                  * We hit the last page and there is more work to be done: wrap
1429                  * back to the start of the file
1430                  */
1431                 scanned = 1;
1432                 index = 0;
1433                 goto retry;
1434         }
1435         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
1436                 mapping->writeback_index = index;
1437
1438         FreeXid(xid);
1439         kfree(iov);
1440         return rc;
1441 }
1442
1443 static int cifs_writepage(struct page *page, struct writeback_control *wbc)
1444 {
1445         int rc = -EFAULT;
1446         int xid;
1447
1448         xid = GetXid();
1449 /* BB add check for wbc flags */
1450         page_cache_get(page);
1451         if (!PageUptodate(page))
1452                 cFYI(1, "ppw - page not up to date");
1453
1454         /*
1455          * Set the "writeback" flag, and clear "dirty" in the radix tree.
1456          *
1457          * A writepage() implementation always needs to do either this,
1458          * or re-dirty the page with "redirty_page_for_writepage()" in
1459          * the case of a failure.
1460          *
1461          * Just unlocking the page will cause the radix tree tag-bits
1462          * to fail to update with the state of the page correctly.
1463          */
1464         set_page_writeback(page);
1465         rc = cifs_partialpagewrite(page, 0, PAGE_CACHE_SIZE);
1466         SetPageUptodate(page); /* BB add check for error and Clearuptodate? */
1467         unlock_page(page);
1468         end_page_writeback(page);
1469         page_cache_release(page);
1470         FreeXid(xid);
1471         return rc;
1472 }
1473
1474 static int cifs_write_end(struct file *file, struct address_space *mapping,
1475                         loff_t pos, unsigned len, unsigned copied,
1476                         struct page *page, void *fsdata)
1477 {
1478         int rc;
1479         struct inode *inode = mapping->host;
1480
1481         cFYI(1, "write_end for page %p from pos %lld with %d bytes",
1482                  page, pos, copied);
1483
1484         if (PageChecked(page)) {
1485                 if (copied == len)
1486                         SetPageUptodate(page);
1487                 ClearPageChecked(page);
1488         } else if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE)
1489                 SetPageUptodate(page);
1490
1491         if (!PageUptodate(page)) {
1492                 char *page_data;
1493                 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
1494                 int xid;
1495
1496                 xid = GetXid();
1497                 /* this is probably better than directly calling
1498                    partialpage_write since in this function the file handle is
1499                    known which we might as well leverage */
1500                 /* BB check if anything else missing out of ppw
1501                    such as updating last write time */
1502                 page_data = kmap(page);
1503                 rc = cifs_write(file->private_data, page_data + offset,
1504                                 copied, &pos);
1505                 /* if (rc < 0) should we set writebehind rc? */
1506                 kunmap(page);
1507
1508                 FreeXid(xid);
1509         } else {
1510                 rc = copied;
1511                 pos += copied;
1512                 set_page_dirty(page);
1513         }
1514
1515         if (rc > 0) {
1516                 spin_lock(&inode->i_lock);
1517                 if (pos > inode->i_size)
1518                         i_size_write(inode, pos);
1519                 spin_unlock(&inode->i_lock);
1520         }
1521
1522         unlock_page(page);
1523         page_cache_release(page);
1524
1525         return rc;
1526 }
1527
1528 int cifs_fsync(struct file *file, int datasync)
1529 {
1530         int xid;
1531         int rc = 0;
1532         struct cifsTconInfo *tcon;
1533         struct cifsFileInfo *smbfile = file->private_data;
1534         struct inode *inode = file->f_path.dentry->d_inode;
1535
1536         xid = GetXid();
1537
1538         cFYI(1, "Sync file - name: %s datasync: 0x%x",
1539                 file->f_path.dentry->d_name.name, datasync);
1540
1541         rc = filemap_write_and_wait(inode->i_mapping);
1542         if (rc == 0) {
1543                 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
1544
1545                 tcon = tlink_tcon(smbfile->tlink);
1546                 if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC))
1547                         rc = CIFSSMBFlush(xid, tcon, smbfile->netfid);
1548         }
1549
1550         FreeXid(xid);
1551         return rc;
1552 }
1553
1554 /* static void cifs_sync_page(struct page *page)
1555 {
1556         struct address_space *mapping;
1557         struct inode *inode;
1558         unsigned long index = page->index;
1559         unsigned int rpages = 0;
1560         int rc = 0;
1561
1562         cFYI(1, "sync page %p", page);
1563         mapping = page->mapping;
1564         if (!mapping)
1565                 return 0;
1566         inode = mapping->host;
1567         if (!inode)
1568                 return; */
1569
1570 /*      fill in rpages then
1571         result = cifs_pagein_inode(inode, index, rpages); */ /* BB finish */
1572
1573 /*      cFYI(1, "rpages is %d for sync page of Index %ld", rpages, index);
1574
1575 #if 0
1576         if (rc < 0)
1577                 return rc;
1578         return 0;
1579 #endif
1580 } */
1581
1582 /*
1583  * As file closes, flush all cached write data for this inode checking
1584  * for write behind errors.
1585  */
1586 int cifs_flush(struct file *file, fl_owner_t id)
1587 {
1588         struct inode *inode = file->f_path.dentry->d_inode;
1589         int rc = 0;
1590
1591         if (file->f_mode & FMODE_WRITE)
1592                 rc = filemap_write_and_wait(inode->i_mapping);
1593
1594         cFYI(1, "Flush inode %p file %p rc %d", inode, file, rc);
1595
1596         return rc;
1597 }
1598
1599 ssize_t cifs_user_read(struct file *file, char __user *read_data,
1600         size_t read_size, loff_t *poffset)
1601 {
1602         int rc = -EACCES;
1603         unsigned int bytes_read = 0;
1604         unsigned int total_read = 0;
1605         unsigned int current_read_size;
1606         struct cifs_sb_info *cifs_sb;
1607         struct cifsTconInfo *pTcon;
1608         int xid;
1609         struct cifsFileInfo *open_file;
1610         char *smb_read_data;
1611         char __user *current_offset;
1612         struct smb_com_read_rsp *pSMBr;
1613
1614         xid = GetXid();
1615         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1616
1617         if (file->private_data == NULL) {
1618                 rc = -EBADF;
1619                 FreeXid(xid);
1620                 return rc;
1621         }
1622         open_file = file->private_data;
1623         pTcon = tlink_tcon(open_file->tlink);
1624
1625         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
1626                 cFYI(1, "attempting read on write only file instance");
1627
1628         for (total_read = 0, current_offset = read_data;
1629              read_size > total_read;
1630              total_read += bytes_read, current_offset += bytes_read) {
1631                 current_read_size = min_t(const int, read_size - total_read,
1632                                           cifs_sb->rsize);
1633                 rc = -EAGAIN;
1634                 smb_read_data = NULL;
1635                 while (rc == -EAGAIN) {
1636                         int buf_type = CIFS_NO_BUFFER;
1637                         if (open_file->invalidHandle) {
1638                                 rc = cifs_reopen_file(open_file, true);
1639                                 if (rc != 0)
1640                                         break;
1641                         }
1642                         rc = CIFSSMBRead(xid, pTcon,
1643                                          open_file->netfid,
1644                                          current_read_size, *poffset,
1645                                          &bytes_read, &smb_read_data,
1646                                          &buf_type);
1647                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
1648                         if (smb_read_data) {
1649                                 if (copy_to_user(current_offset,
1650                                                 smb_read_data +
1651                                                 4 /* RFC1001 length field */ +
1652                                                 le16_to_cpu(pSMBr->DataOffset),
1653                                                 bytes_read))
1654                                         rc = -EFAULT;
1655
1656                                 if (buf_type == CIFS_SMALL_BUFFER)
1657                                         cifs_small_buf_release(smb_read_data);
1658                                 else if (buf_type == CIFS_LARGE_BUFFER)
1659                                         cifs_buf_release(smb_read_data);
1660                                 smb_read_data = NULL;
1661                         }
1662                 }
1663                 if (rc || (bytes_read == 0)) {
1664                         if (total_read) {
1665                                 break;
1666                         } else {
1667                                 FreeXid(xid);
1668                                 return rc;
1669                         }
1670                 } else {
1671                         cifs_stats_bytes_read(pTcon, bytes_read);
1672                         *poffset += bytes_read;
1673                 }
1674         }
1675         FreeXid(xid);
1676         return total_read;
1677 }
1678
1679
1680 static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
1681         loff_t *poffset)
1682 {
1683         int rc = -EACCES;
1684         unsigned int bytes_read = 0;
1685         unsigned int total_read;
1686         unsigned int current_read_size;
1687         struct cifs_sb_info *cifs_sb;
1688         struct cifsTconInfo *pTcon;
1689         int xid;
1690         char *current_offset;
1691         struct cifsFileInfo *open_file;
1692         int buf_type = CIFS_NO_BUFFER;
1693
1694         xid = GetXid();
1695         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1696
1697         if (file->private_data == NULL) {
1698                 rc = -EBADF;
1699                 FreeXid(xid);
1700                 return rc;
1701         }
1702         open_file = file->private_data;
1703         pTcon = tlink_tcon(open_file->tlink);
1704
1705         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
1706                 cFYI(1, "attempting read on write only file instance");
1707
1708         for (total_read = 0, current_offset = read_data;
1709              read_size > total_read;
1710              total_read += bytes_read, current_offset += bytes_read) {
1711                 current_read_size = min_t(const int, read_size - total_read,
1712                                           cifs_sb->rsize);
1713                 /* For windows me and 9x we do not want to request more
1714                 than it negotiated since it will refuse the read then */
1715                 if ((pTcon->ses) &&
1716                         !(pTcon->ses->capabilities & CAP_LARGE_FILES)) {
1717                         current_read_size = min_t(const int, current_read_size,
1718                                         pTcon->ses->server->maxBuf - 128);
1719                 }
1720                 rc = -EAGAIN;
1721                 while (rc == -EAGAIN) {
1722                         if (open_file->invalidHandle) {
1723                                 rc = cifs_reopen_file(open_file, true);
1724                                 if (rc != 0)
1725                                         break;
1726                         }
1727                         rc = CIFSSMBRead(xid, pTcon,
1728                                          open_file->netfid,
1729                                          current_read_size, *poffset,
1730                                          &bytes_read, &current_offset,
1731                                          &buf_type);
1732                 }
1733                 if (rc || (bytes_read == 0)) {
1734                         if (total_read) {
1735                                 break;
1736                         } else {
1737                                 FreeXid(xid);
1738                                 return rc;
1739                         }
1740                 } else {
1741                         cifs_stats_bytes_read(pTcon, total_read);
1742                         *poffset += bytes_read;
1743                 }
1744         }
1745         FreeXid(xid);
1746         return total_read;
1747 }
1748
1749 int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
1750 {
1751         int rc, xid;
1752
1753         xid = GetXid();
1754         rc = cifs_revalidate_file(file);
1755         if (rc) {
1756                 cFYI(1, "Validation prior to mmap failed, error=%d", rc);
1757                 FreeXid(xid);
1758                 return rc;
1759         }
1760         rc = generic_file_mmap(file, vma);
1761         FreeXid(xid);
1762         return rc;
1763 }
1764
1765
1766 static void cifs_copy_cache_pages(struct address_space *mapping,
1767         struct list_head *pages, int bytes_read, char *data)
1768 {
1769         struct page *page;
1770         char *target;
1771
1772         while (bytes_read > 0) {
1773                 if (list_empty(pages))
1774                         break;
1775
1776                 page = list_entry(pages->prev, struct page, lru);
1777                 list_del(&page->lru);
1778
1779                 if (add_to_page_cache_lru(page, mapping, page->index,
1780                                       GFP_KERNEL)) {
1781                         page_cache_release(page);
1782                         cFYI(1, "Add page cache failed");
1783                         data += PAGE_CACHE_SIZE;
1784                         bytes_read -= PAGE_CACHE_SIZE;
1785                         continue;
1786                 }
1787                 page_cache_release(page);
1788
1789                 target = kmap_atomic(page, KM_USER0);
1790
1791                 if (PAGE_CACHE_SIZE > bytes_read) {
1792                         memcpy(target, data, bytes_read);
1793                         /* zero the tail end of this partial page */
1794                         memset(target + bytes_read, 0,
1795                                PAGE_CACHE_SIZE - bytes_read);
1796                         bytes_read = 0;
1797                 } else {
1798                         memcpy(target, data, PAGE_CACHE_SIZE);
1799                         bytes_read -= PAGE_CACHE_SIZE;
1800                 }
1801                 kunmap_atomic(target, KM_USER0);
1802
1803                 flush_dcache_page(page);
1804                 SetPageUptodate(page);
1805                 unlock_page(page);
1806                 data += PAGE_CACHE_SIZE;
1807
1808                 /* add page to FS-Cache */
1809                 cifs_readpage_to_fscache(mapping->host, page);
1810         }
1811         return;
1812 }
1813
1814 static int cifs_readpages(struct file *file, struct address_space *mapping,
1815         struct list_head *page_list, unsigned num_pages)
1816 {
1817         int rc = -EACCES;
1818         int xid;
1819         loff_t offset;
1820         struct page *page;
1821         struct cifs_sb_info *cifs_sb;
1822         struct cifsTconInfo *pTcon;
1823         unsigned int bytes_read = 0;
1824         unsigned int read_size, i;
1825         char *smb_read_data = NULL;
1826         struct smb_com_read_rsp *pSMBr;
1827         struct cifsFileInfo *open_file;
1828         int buf_type = CIFS_NO_BUFFER;
1829
1830         xid = GetXid();
1831         if (file->private_data == NULL) {
1832                 rc = -EBADF;
1833                 FreeXid(xid);
1834                 return rc;
1835         }
1836         open_file = file->private_data;
1837         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1838         pTcon = tlink_tcon(open_file->tlink);
1839
1840         /*
1841          * Reads as many pages as possible from fscache. Returns -ENOBUFS
1842          * immediately if the cookie is negative
1843          */
1844         rc = cifs_readpages_from_fscache(mapping->host, mapping, page_list,
1845                                          &num_pages);
1846         if (rc == 0)
1847                 goto read_complete;
1848
1849         cFYI(DBG2, "rpages: num pages %d", num_pages);
1850         for (i = 0; i < num_pages; ) {
1851                 unsigned contig_pages;
1852                 struct page *tmp_page;
1853                 unsigned long expected_index;
1854
1855                 if (list_empty(page_list))
1856                         break;
1857
1858                 page = list_entry(page_list->prev, struct page, lru);
1859                 offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1860
1861                 /* count adjacent pages that we will read into */
1862                 contig_pages = 0;
1863                 expected_index =
1864                         list_entry(page_list->prev, struct page, lru)->index;
1865                 list_for_each_entry_reverse(tmp_page, page_list, lru) {
1866                         if (tmp_page->index == expected_index) {
1867                                 contig_pages++;
1868                                 expected_index++;
1869                         } else
1870                                 break;
1871                 }
1872                 if (contig_pages + i >  num_pages)
1873                         contig_pages = num_pages - i;
1874
1875                 /* for reads over a certain size could initiate async
1876                    read ahead */
1877
1878                 read_size = contig_pages * PAGE_CACHE_SIZE;
1879                 /* Read size needs to be in multiples of one page */
1880                 read_size = min_t(const unsigned int, read_size,
1881                                   cifs_sb->rsize & PAGE_CACHE_MASK);
1882                 cFYI(DBG2, "rpages: read size 0x%x  contiguous pages %d",
1883                                 read_size, contig_pages);
1884                 rc = -EAGAIN;
1885                 while (rc == -EAGAIN) {
1886                         if (open_file->invalidHandle) {
1887                                 rc = cifs_reopen_file(open_file, true);
1888                                 if (rc != 0)
1889                                         break;
1890                         }
1891
1892                         rc = CIFSSMBRead(xid, pTcon,
1893                                          open_file->netfid,
1894                                          read_size, offset,
1895                                          &bytes_read, &smb_read_data,
1896                                          &buf_type);
1897                         /* BB more RC checks ? */
1898                         if (rc == -EAGAIN) {
1899                                 if (smb_read_data) {
1900                                         if (buf_type == CIFS_SMALL_BUFFER)
1901                                                 cifs_small_buf_release(smb_read_data);
1902                                         else if (buf_type == CIFS_LARGE_BUFFER)
1903                                                 cifs_buf_release(smb_read_data);
1904                                         smb_read_data = NULL;
1905                                 }
1906                         }
1907                 }
1908                 if ((rc < 0) || (smb_read_data == NULL)) {
1909                         cFYI(1, "Read error in readpages: %d", rc);
1910                         break;
1911                 } else if (bytes_read > 0) {
1912                         task_io_account_read(bytes_read);
1913                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
1914                         cifs_copy_cache_pages(mapping, page_list, bytes_read,
1915                                 smb_read_data + 4 /* RFC1001 hdr */ +
1916                                 le16_to_cpu(pSMBr->DataOffset));
1917
1918                         i +=  bytes_read >> PAGE_CACHE_SHIFT;
1919                         cifs_stats_bytes_read(pTcon, bytes_read);
1920                         if ((bytes_read & PAGE_CACHE_MASK) != bytes_read) {
1921                                 i++; /* account for partial page */
1922
1923                                 /* server copy of file can have smaller size
1924                                    than client */
1925                                 /* BB do we need to verify this common case ?
1926                                    this case is ok - if we are at server EOF
1927                                    we will hit it on next read */
1928
1929                                 /* break; */
1930                         }
1931                 } else {
1932                         cFYI(1, "No bytes read (%d) at offset %lld . "
1933                                 "Cleaning remaining pages from readahead list",
1934                                 bytes_read, offset);
1935                         /* BB turn off caching and do new lookup on
1936                            file size at server? */
1937                         break;
1938                 }
1939                 if (smb_read_data) {
1940                         if (buf_type == CIFS_SMALL_BUFFER)
1941                                 cifs_small_buf_release(smb_read_data);
1942                         else if (buf_type == CIFS_LARGE_BUFFER)
1943                                 cifs_buf_release(smb_read_data);
1944                         smb_read_data = NULL;
1945                 }
1946                 bytes_read = 0;
1947         }
1948
1949 /* need to free smb_read_data buf before exit */
1950         if (smb_read_data) {
1951                 if (buf_type == CIFS_SMALL_BUFFER)
1952                         cifs_small_buf_release(smb_read_data);
1953                 else if (buf_type == CIFS_LARGE_BUFFER)
1954                         cifs_buf_release(smb_read_data);
1955                 smb_read_data = NULL;
1956         }
1957
1958 read_complete:
1959         FreeXid(xid);
1960         return rc;
1961 }
1962
1963 static int cifs_readpage_worker(struct file *file, struct page *page,
1964         loff_t *poffset)
1965 {
1966         char *read_data;
1967         int rc;
1968
1969         /* Is the page cached? */
1970         rc = cifs_readpage_from_fscache(file->f_path.dentry->d_inode, page);
1971         if (rc == 0)
1972                 goto read_complete;
1973
1974         page_cache_get(page);
1975         read_data = kmap(page);
1976         /* for reads over a certain size could initiate async read ahead */
1977
1978         rc = cifs_read(file, read_data, PAGE_CACHE_SIZE, poffset);
1979
1980         if (rc < 0)
1981                 goto io_error;
1982         else
1983                 cFYI(1, "Bytes read %d", rc);
1984
1985         file->f_path.dentry->d_inode->i_atime =
1986                 current_fs_time(file->f_path.dentry->d_inode->i_sb);
1987
1988         if (PAGE_CACHE_SIZE > rc)
1989                 memset(read_data + rc, 0, PAGE_CACHE_SIZE - rc);
1990
1991         flush_dcache_page(page);
1992         SetPageUptodate(page);
1993
1994         /* send this page to the cache */
1995         cifs_readpage_to_fscache(file->f_path.dentry->d_inode, page);
1996
1997         rc = 0;
1998
1999 io_error:
2000         kunmap(page);
2001         page_cache_release(page);
2002
2003 read_complete:
2004         return rc;
2005 }
2006
2007 static int cifs_readpage(struct file *file, struct page *page)
2008 {
2009         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
2010         int rc = -EACCES;
2011         int xid;
2012
2013         xid = GetXid();
2014
2015         if (file->private_data == NULL) {
2016                 rc = -EBADF;
2017                 FreeXid(xid);
2018                 return rc;
2019         }
2020
2021         cFYI(1, "readpage %p at offset %d 0x%x\n",
2022                  page, (int)offset, (int)offset);
2023
2024         rc = cifs_readpage_worker(file, page, &offset);
2025
2026         unlock_page(page);
2027
2028         FreeXid(xid);
2029         return rc;
2030 }
2031
2032 static int is_inode_writable(struct cifsInodeInfo *cifs_inode)
2033 {
2034         struct cifsFileInfo *open_file;
2035
2036         spin_lock(&cifs_file_list_lock);
2037         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
2038                 if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
2039                         spin_unlock(&cifs_file_list_lock);
2040                         return 1;
2041                 }
2042         }
2043         spin_unlock(&cifs_file_list_lock);
2044         return 0;
2045 }
2046
2047 /* We do not want to update the file size from server for inodes
2048    open for write - to avoid races with writepage extending
2049    the file - in the future we could consider allowing
2050    refreshing the inode only on increases in the file size
2051    but this is tricky to do without racing with writebehind
2052    page caching in the current Linux kernel design */
2053 bool is_size_safe_to_change(struct cifsInodeInfo *cifsInode, __u64 end_of_file)
2054 {
2055         if (!cifsInode)
2056                 return true;
2057
2058         if (is_inode_writable(cifsInode)) {
2059                 /* This inode is open for write at least once */
2060                 struct cifs_sb_info *cifs_sb;
2061
2062                 cifs_sb = CIFS_SB(cifsInode->vfs_inode.i_sb);
2063                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO) {
2064                         /* since no page cache to corrupt on directio
2065                         we can change size safely */
2066                         return true;
2067                 }
2068
2069                 if (i_size_read(&cifsInode->vfs_inode) < end_of_file)
2070                         return true;
2071
2072                 return false;
2073         } else
2074                 return true;
2075 }
2076
2077 static int cifs_write_begin(struct file *file, struct address_space *mapping,
2078                         loff_t pos, unsigned len, unsigned flags,
2079                         struct page **pagep, void **fsdata)
2080 {
2081         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
2082         loff_t offset = pos & (PAGE_CACHE_SIZE - 1);
2083         loff_t page_start = pos & PAGE_MASK;
2084         loff_t i_size;
2085         struct page *page;
2086         int rc = 0;
2087
2088         cFYI(1, "write_begin from %lld len %d", (long long)pos, len);
2089
2090         page = grab_cache_page_write_begin(mapping, index, flags);
2091         if (!page) {
2092                 rc = -ENOMEM;
2093                 goto out;
2094         }
2095
2096         if (PageUptodate(page))
2097                 goto out;
2098
2099         /*
2100          * If we write a full page it will be up to date, no need to read from
2101          * the server. If the write is short, we'll end up doing a sync write
2102          * instead.
2103          */
2104         if (len == PAGE_CACHE_SIZE)
2105                 goto out;
2106
2107         /*
2108          * optimize away the read when we have an oplock, and we're not
2109          * expecting to use any of the data we'd be reading in. That
2110          * is, when the page lies beyond the EOF, or straddles the EOF
2111          * and the write will cover all of the existing data.
2112          */
2113         if (CIFS_I(mapping->host)->clientCanCacheRead) {
2114                 i_size = i_size_read(mapping->host);
2115                 if (page_start >= i_size ||
2116                     (offset == 0 && (pos + len) >= i_size)) {
2117                         zero_user_segments(page, 0, offset,
2118                                            offset + len,
2119                                            PAGE_CACHE_SIZE);
2120                         /*
2121                          * PageChecked means that the parts of the page
2122                          * to which we're not writing are considered up
2123                          * to date. Once the data is copied to the
2124                          * page, it can be set uptodate.
2125                          */
2126                         SetPageChecked(page);
2127                         goto out;
2128                 }
2129         }
2130
2131         if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
2132                 /*
2133                  * might as well read a page, it is fast enough. If we get
2134                  * an error, we don't need to return it. cifs_write_end will
2135                  * do a sync write instead since PG_uptodate isn't set.
2136                  */
2137                 cifs_readpage_worker(file, page, &page_start);
2138         } else {
2139                 /* we could try using another file handle if there is one -
2140                    but how would we lock it to prevent close of that handle
2141                    racing with this read? In any case
2142                    this will be written out by write_end so is fine */
2143         }
2144 out:
2145         *pagep = page;
2146         return rc;
2147 }
2148
2149 static int cifs_release_page(struct page *page, gfp_t gfp)
2150 {
2151         if (PagePrivate(page))
2152                 return 0;
2153
2154         return cifs_fscache_release_page(page, gfp);
2155 }
2156
2157 static void cifs_invalidate_page(struct page *page, unsigned long offset)
2158 {
2159         struct cifsInodeInfo *cifsi = CIFS_I(page->mapping->host);
2160
2161         if (offset == 0)
2162                 cifs_fscache_invalidate_page(page, &cifsi->vfs_inode);
2163 }
2164
2165 void cifs_oplock_break(struct work_struct *work)
2166 {
2167         struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
2168                                                   oplock_break);
2169         struct inode *inode = cfile->dentry->d_inode;
2170         struct cifsInodeInfo *cinode = CIFS_I(inode);
2171         int rc = 0;
2172
2173         if (inode && S_ISREG(inode->i_mode)) {
2174                 if (cinode->clientCanCacheRead)
2175                         break_lease(inode, O_RDONLY);
2176                 else
2177                         break_lease(inode, O_WRONLY);
2178                 rc = filemap_fdatawrite(inode->i_mapping);
2179                 if (cinode->clientCanCacheRead == 0) {
2180                         rc = filemap_fdatawait(inode->i_mapping);
2181                         mapping_set_error(inode->i_mapping, rc);
2182                         invalidate_remote_inode(inode);
2183                 }
2184                 cFYI(1, "Oplock flush inode %p rc %d", inode, rc);
2185         }
2186
2187         /*
2188          * releasing stale oplock after recent reconnect of smb session using
2189          * a now incorrect file handle is not a data integrity issue but do
2190          * not bother sending an oplock release if session to server still is
2191          * disconnected since oplock already released by the server
2192          */
2193         if (!cfile->oplock_break_cancelled) {
2194                 rc = CIFSSMBLock(0, tlink_tcon(cfile->tlink), cfile->netfid, 0,
2195                                  0, 0, 0, LOCKING_ANDX_OPLOCK_RELEASE, false);
2196                 cFYI(1, "Oplock release rc = %d", rc);
2197         }
2198
2199         /*
2200          * We might have kicked in before is_valid_oplock_break()
2201          * finished grabbing reference for us.  Make sure it's done by
2202          * waiting for cifs_file_list_lock.
2203          */
2204         spin_lock(&cifs_file_list_lock);
2205         spin_unlock(&cifs_file_list_lock);
2206
2207         cifs_oplock_break_put(cfile);
2208 }
2209
2210 /* must be called while holding cifs_file_list_lock */
2211 void cifs_oplock_break_get(struct cifsFileInfo *cfile)
2212 {
2213         cifs_sb_active(cfile->dentry->d_sb);
2214         cifsFileInfo_get(cfile);
2215 }
2216
2217 void cifs_oplock_break_put(struct cifsFileInfo *cfile)
2218 {
2219         struct super_block *sb = cfile->dentry->d_sb;
2220
2221         cifsFileInfo_put(cfile);
2222         cifs_sb_deactive(sb);
2223 }
2224
2225 const struct address_space_operations cifs_addr_ops = {
2226         .readpage = cifs_readpage,
2227         .readpages = cifs_readpages,
2228         .writepage = cifs_writepage,
2229         .writepages = cifs_writepages,
2230         .write_begin = cifs_write_begin,
2231         .write_end = cifs_write_end,
2232         .set_page_dirty = __set_page_dirty_nobuffers,
2233         .releasepage = cifs_release_page,
2234         .invalidatepage = cifs_invalidate_page,
2235         /* .sync_page = cifs_sync_page, */
2236         /* .direct_IO = */
2237 };
2238
2239 /*
2240  * cifs_readpages requires the server to support a buffer large enough to
2241  * contain the header plus one complete page of data.  Otherwise, we need
2242  * to leave cifs_readpages out of the address space operations.
2243  */
2244 const struct address_space_operations cifs_addr_ops_smallbuf = {
2245         .readpage = cifs_readpage,
2246         .writepage = cifs_writepage,
2247         .writepages = cifs_writepages,
2248         .write_begin = cifs_write_begin,
2249         .write_end = cifs_write_end,
2250         .set_page_dirty = __set_page_dirty_nobuffers,
2251         .releasepage = cifs_release_page,
2252         .invalidatepage = cifs_invalidate_page,
2253         /* .sync_page = cifs_sync_page, */
2254         /* .direct_IO = */
2255 };