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., 2002,2003
   7  *   Author(s): Steve French (sfrench@us.ibm.com)
   8  *
   9  *   This library is free software; you can redistribute it and/or modify
  10  *   it under the terms of the GNU Lesser General Public License as published
  11  *   by the Free Software Foundation; either version 2.1 of the License, or
  12  *   (at your option) any later version.
  13  *
  14  *   This library is distributed in the hope that it will be useful,
  15  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  17  *   the GNU Lesser General Public License for more details.
  18  *
  19  *   You should have received a copy of the GNU Lesser General Public License
  20  *   along with this library; if not, write to the Free Software
  21  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22  */
  23 #include <linux/fs.h>
  24 #include <linux/backing-dev.h>
  25 #include <linux/stat.h>
  26 #include <linux/fcntl.h>
  27 #include <linux/mpage.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/pagevec.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/writeback.h>
  32 #include <linux/delay.h>
  33 #include <asm/div64.h>
  34 #include "cifsfs.h"
  35 #include "cifspdu.h"
  36 #include "cifsglob.h"
  37 #include "cifsproto.h"
  38 #include "cifs_unicode.h"
  39 #include "cifs_debug.h"
  40 #include "cifs_fs_sb.h"
  41
  42 static inline struct cifsFileInfo *cifs_init_private(
  43         struct cifsFileInfo *private_data, struct inode *inode,
  44         struct file *file, __u16 netfid)
  45 {
  46         memset(private_data, 0, sizeof(struct cifsFileInfo));
  47         private_data->netfid = netfid;
  48         private_data->pid = current->tgid;
  49         init_MUTEX(&private_data->fh_sem);
  50         private_data->pfile = file; /* needed for writepage */
  51         private_data->pInode = inode;
  52         private_data->invalidHandle = FALSE;
  53         private_data->closePend = FALSE;
  54         /* we have to track num writers to the inode, since writepages
  55         does not tell us which handle the write is for so there can
  56         be a close (overlapping with write) of the filehandle that
  57         cifs_writepages chose to use */
  58         atomic_set(&private_data->wrtPending,0);
  59
  60         return private_data;
  61 }
  62
  63 static inline int cifs_convert_flags(unsigned int flags)
  64 {
  65         if ((flags & O_ACCMODE) == O_RDONLY)
  66                 return GENERIC_READ;
  67         else if ((flags & O_ACCMODE) == O_WRONLY)
  68                 return GENERIC_WRITE;
  69         else if ((flags & O_ACCMODE) == O_RDWR) {
  70                 /* GENERIC_ALL is too much permission to request
  71                    can cause unnecessary access denied on create */
  72                 /* return GENERIC_ALL; */
  73                 return (GENERIC_READ | GENERIC_WRITE);
  74         }
  75
  76         return 0x20197;
  77 }
  78
  79 static inline int cifs_get_disposition(unsigned int flags)
  80 {
  81         if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
  82                 return FILE_CREATE;
  83         else if ((flags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
  84                 return FILE_OVERWRITE_IF;
  85         else if ((flags & O_CREAT) == O_CREAT)
  86                 return FILE_OPEN_IF;
  87         else
  88                 return FILE_OPEN;
  89 }
  90
  91 /* all arguments to this function must be checked for validity in caller */
  92 static inline int cifs_open_inode_helper(struct inode *inode, struct file *file,
  93         struct cifsInodeInfo *pCifsInode, struct cifsFileInfo *pCifsFile,
  94         struct cifsTconInfo *pTcon, int *oplock, FILE_ALL_INFO *buf,
  95         char *full_path, int xid)
  96 {
  97         struct timespec temp;
  98         int rc;
  99
 100         /* want handles we can use to read with first
 101            in the list so we do not have to walk the
 102            list to search for one in prepare_write */
 103         if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
 104                 list_add_tail(&pCifsFile->flist,
 105                               &pCifsInode->openFileList);
 106         } else {
 107                 list_add(&pCifsFile->flist,
 108                          &pCifsInode->openFileList);
 109         }
 110         write_unlock(&GlobalSMBSeslock);
 111         write_unlock(&file->f_owner.lock);
 112         if (pCifsInode->clientCanCacheRead) {
 113                 /* we have the inode open somewhere else
 114                    no need to discard cache data */
 115                 goto client_can_cache;
 116         }
 117
 118         /* BB need same check in cifs_create too? */
 119         /* if not oplocked, invalidate inode pages if mtime or file
 120            size changed */
 121         temp = cifs_NTtimeToUnix(le64_to_cpu(buf->LastWriteTime));
 122         if (timespec_equal(&file->f_dentry->d_inode->i_mtime, &temp) &&
 123                            (file->f_dentry->d_inode->i_size ==
 124                             (loff_t)le64_to_cpu(buf->EndOfFile))) {
 125                 cFYI(1, ("inode unchanged on server"));
 126         } else {
 127                 if (file->f_dentry->d_inode->i_mapping) {
 128                 /* BB no need to lock inode until after invalidate
 129                    since namei code should already have it locked? */
 130                         filemap_write_and_wait(file->f_dentry->d_inode->i_mapping);
 131                 }
 132                 cFYI(1, ("invalidating remote inode since open detected it "
 133                          "changed"));
 134                 invalidate_remote_inode(file->f_dentry->d_inode);
 135         }
 136
 137 client_can_cache:
 138         if (pTcon->ses->capabilities & CAP_UNIX)
 139                 rc = cifs_get_inode_info_unix(&file->f_dentry->d_inode,
 140                         full_path, inode->i_sb, xid);
 141         else
 142                 rc = cifs_get_inode_info(&file->f_dentry->d_inode,
 143                         full_path, buf, inode->i_sb, xid);
 144
 145         if ((*oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 146                 pCifsInode->clientCanCacheAll = TRUE;
 147                 pCifsInode->clientCanCacheRead = TRUE;
 148                 cFYI(1, ("Exclusive Oplock granted on inode %p",
 149                          file->f_dentry->d_inode));
 150         } else if ((*oplock & 0xF) == OPLOCK_READ)
 151                 pCifsInode->clientCanCacheRead = TRUE;
 152
 153         return rc;
 154 }
 155
 156 int cifs_open(struct inode *inode, struct file *file)
 157 {
 158         int rc = -EACCES;
 159         int xid, oplock;
 160         struct cifs_sb_info *cifs_sb;
 161         struct cifsTconInfo *pTcon;
 162         struct cifsFileInfo *pCifsFile;
 163         struct cifsInodeInfo *pCifsInode;
 164         struct list_head *tmp;
 165         char *full_path = NULL;
 166         int desiredAccess;
 167         int disposition;
 168         __u16 netfid;
 169         FILE_ALL_INFO *buf = NULL;
 170
 171         xid = GetXid();
 172
 173         cifs_sb = CIFS_SB(inode->i_sb);
 174         pTcon = cifs_sb->tcon;
 175
 176         if (file->f_flags & O_CREAT) {
 177                 /* search inode for this file and fill in file->private_data */
 178                 pCifsInode = CIFS_I(file->f_dentry->d_inode);
 179                 read_lock(&GlobalSMBSeslock);
 180                 list_for_each(tmp, &pCifsInode->openFileList) {
 181                         pCifsFile = list_entry(tmp, struct cifsFileInfo,
 182                                                flist);
 183                         if ((pCifsFile->pfile == NULL) &&
 184                             (pCifsFile->pid == current->tgid)) {
 185                                 /* mode set in cifs_create */
 186
 187                                 /* needed for writepage */
 188                                 pCifsFile->pfile = file;
 189
 190                                 file->private_data = pCifsFile;
 191                                 break;
 192                         }
 193                 }
 194                 read_unlock(&GlobalSMBSeslock);
 195                 if (file->private_data != NULL) {
 196                         rc = 0;
 197                         FreeXid(xid);
 198                         return rc;
 199                 } else {
 200                         if (file->f_flags & O_EXCL)
 201                                 cERROR(1, ("could not find file instance for "
 202                                            "new file %p ", file));
 203                 }
 204         }
 205
 206         full_path = build_path_from_dentry(file->f_dentry);
 207         if (full_path == NULL) {
 208                 FreeXid(xid);
 209                 return -ENOMEM;
 210         }
 211
 212         cFYI(1, (" inode = 0x%p file flags are 0x%x for %s",
 213                  inode, file->f_flags, full_path));
 214         desiredAccess = cifs_convert_flags(file->f_flags);
 215
 216 /*********************************************************************
 217  *  open flag mapping table:
 218  *
 219  *      POSIX Flag            CIFS Disposition
 220  *      ----------            ----------------
 221  *      O_CREAT               FILE_OPEN_IF
 222  *      O_CREAT | O_EXCL      FILE_CREATE
 223  *      O_CREAT | O_TRUNC     FILE_OVERWRITE_IF
 224  *      O_TRUNC               FILE_OVERWRITE
 225  *      none of the above     FILE_OPEN
 226  *
 227  *      Note that there is not a direct match between disposition
 228  *      FILE_SUPERSEDE (ie create whether or not file exists although
 229  *      O_CREAT | O_TRUNC is similar but truncates the existing
 230  *      file rather than creating a new file as FILE_SUPERSEDE does
 231  *      (which uses the attributes / metadata passed in on open call)
 232  *?
 233  *?  O_SYNC is a reasonable match to CIFS writethrough flag
 234  *?  and the read write flags match reasonably.  O_LARGEFILE
 235  *?  is irrelevant because largefile support is always used
 236  *?  by this client. Flags O_APPEND, O_DIRECT, O_DIRECTORY,
 237  *       O_FASYNC, O_NOFOLLOW, O_NONBLOCK need further investigation
 238  *********************************************************************/
 239
 240         disposition = cifs_get_disposition(file->f_flags);
 241
 242         if (oplockEnabled)
 243                 oplock = REQ_OPLOCK;
 244         else
 245                 oplock = FALSE;
 246
 247         /* BB pass O_SYNC flag through on file attributes .. BB */
 248
 249         /* Also refresh inode by passing in file_info buf returned by SMBOpen
 250            and calling get_inode_info with returned buf (at least helps
 251            non-Unix server case) */
 252
 253         /* BB we can not do this if this is the second open of a file
 254            and the first handle has writebehind data, we might be
 255            able to simply do a filemap_fdatawrite/filemap_fdatawait first */
 256         buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 257         if (!buf) {
 258                 rc = -ENOMEM;
 259                 goto out;
 260         }
 261         rc = CIFSSMBOpen(xid, pTcon, full_path, disposition, desiredAccess,
 262                          CREATE_NOT_DIR, &netfid, &oplock, buf,
 263                          cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
 264                                  & CIFS_MOUNT_MAP_SPECIAL_CHR);
 265         if (rc == -EIO) {
 266                 /* Old server, try legacy style OpenX */
 267                 rc = SMBLegacyOpen(xid, pTcon, full_path, disposition,
 268                         desiredAccess, CREATE_NOT_DIR, &netfid, &oplock, buf,
 269                         cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
 270                                 & CIFS_MOUNT_MAP_SPECIAL_CHR);
 271         }
 272         if (rc) {
 273                 cFYI(1, ("cifs_open returned 0x%x ", rc));
 274                 goto out;
 275         }
 276         file->private_data =
 277                 kmalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 278         if (file->private_data == NULL) {
 279                 rc = -ENOMEM;
 280                 goto out;
 281         }
 282         pCifsFile = cifs_init_private(file->private_data, inode, file, netfid);
 283         write_lock(&file->f_owner.lock);
 284         write_lock(&GlobalSMBSeslock);
 285         list_add(&pCifsFile->tlist, &pTcon->openFileList);
 286
 287         pCifsInode = CIFS_I(file->f_dentry->d_inode);
 288         if (pCifsInode) {
 289                 rc = cifs_open_inode_helper(inode, file, pCifsInode,
 290                                             pCifsFile, pTcon,
 291                                             &oplock, buf, full_path, xid);
 292         } else {
 293                 write_unlock(&GlobalSMBSeslock);
 294                 write_unlock(&file->f_owner.lock);
 295         }
 296
 297         if (oplock & CIFS_CREATE_ACTION) {
 298                 /* time to set mode which we can not set earlier due to
 299                    problems creating new read-only files */
 300                 if (cifs_sb->tcon->ses->capabilities & CAP_UNIX) {
 301                         CIFSSMBUnixSetPerms(xid, pTcon, full_path,
 302                                             inode->i_mode,
 303                                             (__u64)-1, (__u64)-1, 0 /* dev */,
 304                                             cifs_sb->local_nls,
 305                                             cifs_sb->mnt_cifs_flags &
 306                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 307                 } else {
 308                         /* BB implement via Windows security descriptors eg
 309                            CIFSSMBWinSetPerms(xid, pTcon, full_path, mode,
 310                                               -1, -1, local_nls);
 311                            in the meantime could set r/o dos attribute when
 312                            perms are eg: mode & 0222 == 0 */
 313                 }
 314         }
 315
 316 out:
 317         kfree(buf);
 318         kfree(full_path);
 319         FreeXid(xid);
 320         return rc;
 321 }
 322
 323 /* Try to reaquire byte range locks that were released when session */
 324 /* to server was lost */
 325 static int cifs_relock_file(struct cifsFileInfo *cifsFile)
 326 {
 327         int rc = 0;
 328
 329 /* BB list all locks open on this file and relock */
 330
 331         return rc;
 332 }
 333
 334 static int cifs_reopen_file(struct inode *inode, struct file *file,
 335         int can_flush)
 336 {
 337         int rc = -EACCES;
 338         int xid, oplock;
 339         struct cifs_sb_info *cifs_sb;
 340         struct cifsTconInfo *pTcon;
 341         struct cifsFileInfo *pCifsFile;
 342         struct cifsInodeInfo *pCifsInode;
 343         char *full_path = NULL;
 344         int desiredAccess;
 345         int disposition = FILE_OPEN;
 346         __u16 netfid;
 347
 348         if (inode == NULL)
 349                 return -EBADF;
 350         if (file->private_data) {
 351                 pCifsFile = (struct cifsFileInfo *)file->private_data;
 352         } else
 353                 return -EBADF;
 354
 355         xid = GetXid();
 356         down(&pCifsFile->fh_sem);
 357         if (pCifsFile->invalidHandle == FALSE) {
 358                 up(&pCifsFile->fh_sem);
 359                 FreeXid(xid);
 360                 return 0;
 361         }
 362
 363         if (file->f_dentry == NULL) {
 364                 up(&pCifsFile->fh_sem);
 365                 cFYI(1, ("failed file reopen, no valid name if dentry freed"));
 366                 FreeXid(xid);
 367                 return -EBADF;
 368         }
 369         cifs_sb = CIFS_SB(inode->i_sb);
 370         pTcon = cifs_sb->tcon;
 371 /* can not grab rename sem here because various ops, including
 372    those that already have the rename sem can end up causing writepage
 373    to get called and if the server was down that means we end up here,
 374    and we can never tell if the caller already has the rename_sem */
 375         full_path = build_path_from_dentry(file->f_dentry);
 376         if (full_path == NULL) {
 377                 up(&pCifsFile->fh_sem);
 378                 FreeXid(xid);
 379                 return -ENOMEM;
 380         }
 381
 382         cFYI(1, (" inode = 0x%p file flags are 0x%x for %s",
 383                  inode, file->f_flags,full_path));
 384         desiredAccess = cifs_convert_flags(file->f_flags);
 385
 386         if (oplockEnabled)
 387                 oplock = REQ_OPLOCK;
 388         else
 389                 oplock = FALSE;
 390
 391         /* Can not refresh inode by passing in file_info buf to be returned
 392            by SMBOpen and then calling get_inode_info with returned buf
 393            since file might have write behind data that needs to be flushed
 394            and server version of file size can be stale. If we knew for sure
 395            that inode was not dirty locally we could do this */
 396
 397 /*      buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 398         if (buf == 0) {
 399                 up(&pCifsFile->fh_sem);
 400                 kfree(full_path);
 401                 FreeXid(xid);
 402                 return -ENOMEM;
 403         } */
 404         rc = CIFSSMBOpen(xid, pTcon, full_path, disposition, desiredAccess,
 405                          CREATE_NOT_DIR, &netfid, &oplock, NULL,
 406                          cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
 407                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 408         if (rc) {
 409                 up(&pCifsFile->fh_sem);
 410                 cFYI(1, ("cifs_open returned 0x%x ", rc));
 411                 cFYI(1, ("oplock: %d ", oplock));
 412         } else {
 413                 pCifsFile->netfid = netfid;
 414                 pCifsFile->invalidHandle = FALSE;
 415                 up(&pCifsFile->fh_sem);
 416                 pCifsInode = CIFS_I(inode);
 417                 if (pCifsInode) {
 418                         if (can_flush) {
 419                                 filemap_write_and_wait(inode->i_mapping);
 420                         /* temporarily disable caching while we
 421                            go to server to get inode info */
 422                                 pCifsInode->clientCanCacheAll = FALSE;
 423                                 pCifsInode->clientCanCacheRead = FALSE;
 424                                 if (pTcon->ses->capabilities & CAP_UNIX)
 425                                         rc = cifs_get_inode_info_unix(&inode,
 426                                                 full_path, inode->i_sb, xid);
 427                                 else
 428                                         rc = cifs_get_inode_info(&inode,
 429                                                 full_path, NULL, inode->i_sb,
 430                                                 xid);
 431                         } /* else we are writing out data to server already
 432                              and could deadlock if we tried to flush data, and
 433                              since we do not know if we have data that would
 434                              invalidate the current end of file on the server
 435                              we can not go to the server to get the new inod
 436                              info */
 437                         if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 438                                 pCifsInode->clientCanCacheAll = TRUE;
 439                                 pCifsInode->clientCanCacheRead = TRUE;
 440                                 cFYI(1, ("Exclusive Oplock granted on inode %p",
 441                                          file->f_dentry->d_inode));
 442                         } else if ((oplock & 0xF) == OPLOCK_READ) {
 443                                 pCifsInode->clientCanCacheRead = TRUE;
 444                                 pCifsInode->clientCanCacheAll = FALSE;
 445                         } else {
 446                                 pCifsInode->clientCanCacheRead = FALSE;
 447                                 pCifsInode->clientCanCacheAll = FALSE;
 448                         }
 449                         cifs_relock_file(pCifsFile);
 450                 }
 451         }
 452
 453         kfree(full_path);
 454         FreeXid(xid);
 455         return rc;
 456 }
 457
 458 int cifs_close(struct inode *inode, struct file *file)
 459 {
 460         int rc = 0;
 461         int xid;
 462         struct cifs_sb_info *cifs_sb;
 463         struct cifsTconInfo *pTcon;
 464         struct cifsFileInfo *pSMBFile =
 465                 (struct cifsFileInfo *)file->private_data;
 466
 467         xid = GetXid();
 468
 469         cifs_sb = CIFS_SB(inode->i_sb);
 470         pTcon = cifs_sb->tcon;
 471         if (pSMBFile) {
 472                 pSMBFile->closePend = TRUE;
 473                 write_lock(&file->f_owner.lock);
 474                 if (pTcon) {
 475                         /* no sense reconnecting to close a file that is
 476                            already closed */
 477                         if (pTcon->tidStatus != CifsNeedReconnect) {
 478                                 int timeout = 2;
 479                                 while((atomic_read(&pSMBFile->wrtPending) != 0)
 480                                          && (timeout < 1000) ) {
 481                                         /* Give write a better chance to get to
 482                                         server ahead of the close.  We do not
 483                                         want to add a wait_q here as it would
 484                                         increase the memory utilization as
 485                                         the struct would be in each open file,
 486                                         but this should give enough time to
 487                                         clear the socket */
 488                                         write_unlock(&file->f_owner.lock);
 489                                         cERROR(1,("close with pending writes"));
 490                                         msleep(timeout);
 491                                         write_lock(&file->f_owner.lock);
 492                                         timeout *= 4;
 493                                 }
 494                                 write_unlock(&file->f_owner.lock);
 495                                 rc = CIFSSMBClose(xid, pTcon,
 496                                                   pSMBFile->netfid);
 497                                 write_lock(&file->f_owner.lock);
 498                         }
 499                 }
 500                 write_lock(&GlobalSMBSeslock);
 501                 list_del(&pSMBFile->flist);
 502                 list_del(&pSMBFile->tlist);
 503                 write_unlock(&GlobalSMBSeslock);
 504                 write_unlock(&file->f_owner.lock);
 505                 kfree(pSMBFile->search_resume_name);
 506                 kfree(file->private_data);
 507                 file->private_data = NULL;
 508         } else
 509                 rc = -EBADF;
 510
 511         if (list_empty(&(CIFS_I(inode)->openFileList))) {
 512                 cFYI(1, ("closing last open instance for inode %p", inode));
 513                 /* if the file is not open we do not know if we can cache info
 514                    on this inode, much less write behind and read ahead */
 515                 CIFS_I(inode)->clientCanCacheRead = FALSE;
 516                 CIFS_I(inode)->clientCanCacheAll  = FALSE;
 517         }
 518         if ((rc ==0) && CIFS_I(inode)->write_behind_rc)
 519                 rc = CIFS_I(inode)->write_behind_rc;
 520         FreeXid(xid);
 521         return rc;
 522 }
 523
 524 int cifs_closedir(struct inode *inode, struct file *file)
 525 {
 526         int rc = 0;
 527         int xid;
 528         struct cifsFileInfo *pCFileStruct =
 529             (struct cifsFileInfo *)file->private_data;
 530         char *ptmp;
 531
 532         cFYI(1, ("Closedir inode = 0x%p with ", inode));
 533
 534         xid = GetXid();
 535
 536         if (pCFileStruct) {
 537                 struct cifsTconInfo *pTcon;
 538                 struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_dentry->d_sb);
 539
 540                 pTcon = cifs_sb->tcon;
 541
 542                 cFYI(1, ("Freeing private data in close dir"));
 543                 if ((pCFileStruct->srch_inf.endOfSearch == FALSE) &&
 544                    (pCFileStruct->invalidHandle == FALSE)) {
 545                         pCFileStruct->invalidHandle = TRUE;
 546                         rc = CIFSFindClose(xid, pTcon, pCFileStruct->netfid);
 547                         cFYI(1, ("Closing uncompleted readdir with rc %d",
 548                                  rc));
 549                         /* not much we can do if it fails anyway, ignore rc */
 550                         rc = 0;
 551                 }
 552                 ptmp = pCFileStruct->srch_inf.ntwrk_buf_start;
 553                 if (ptmp) {
 554                         cFYI(1, ("closedir free smb buf in srch struct"));
 555                         pCFileStruct->srch_inf.ntwrk_buf_start = NULL;
 556                         if(pCFileStruct->srch_inf.smallBuf)
 557                                 cifs_small_buf_release(ptmp);
 558                         else
 559                                 cifs_buf_release(ptmp);
 560                 }
 561                 ptmp = pCFileStruct->search_resume_name;
 562                 if (ptmp) {
 563                         cFYI(1, ("closedir free resume name"));
 564                         pCFileStruct->search_resume_name = NULL;
 565                         kfree(ptmp);
 566                 }
 567                 kfree(file->private_data);
 568                 file->private_data = NULL;
 569         }
 570         /* BB can we lock the filestruct while this is going on? */
 571         FreeXid(xid);
 572         return rc;
 573 }
 574
 575 int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
 576 {
 577         int rc, xid;
 578         __u32 numLock = 0;
 579         __u32 numUnlock = 0;
 580         __u64 length;
 581         int wait_flag = FALSE;
 582         struct cifs_sb_info *cifs_sb;
 583         struct cifsTconInfo *pTcon;
 584         __u16 netfid;
 585         __u8 lockType = LOCKING_ANDX_LARGE_FILES;
 586
 587         length = 1 + pfLock->fl_end - pfLock->fl_start;
 588         rc = -EACCES;
 589         xid = GetXid();
 590
 591         cFYI(1, ("Lock parm: 0x%x flockflags: "
 592                  "0x%x flocktype: 0x%x start: %lld end: %lld",
 593                 cmd, pfLock->fl_flags, pfLock->fl_type, pfLock->fl_start,
 594                 pfLock->fl_end));
 595
 596         if (pfLock->fl_flags & FL_POSIX)
 597                 cFYI(1, ("Posix"));
 598         if (pfLock->fl_flags & FL_FLOCK)
 599                 cFYI(1, ("Flock"));
 600         if (pfLock->fl_flags & FL_SLEEP) {
 601                 cFYI(1, ("Blocking lock"));
 602                 wait_flag = TRUE;
 603         }
 604         if (pfLock->fl_flags & FL_ACCESS)
 605                 cFYI(1, ("Process suspended by mandatory locking - "
 606                          "not implemented yet "));
 607         if (pfLock->fl_flags & FL_LEASE)
 608                 cFYI(1, ("Lease on file - not implemented yet"));
 609         if (pfLock->fl_flags &
 610             (~(FL_POSIX | FL_FLOCK | FL_SLEEP | FL_ACCESS | FL_LEASE)))
 611                 cFYI(1, ("Unknown lock flags 0x%x", pfLock->fl_flags));
 612
 613         if (pfLock->fl_type == F_WRLCK) {
 614                 cFYI(1, ("F_WRLCK "));
 615                 numLock = 1;
 616         } else if (pfLock->fl_type == F_UNLCK) {
 617                 cFYI(1, ("F_UNLCK"));
 618                 numUnlock = 1;
 619                 /* Check if unlock includes more than
 620                 one lock range */
 621         } else if (pfLock->fl_type == F_RDLCK) {
 622                 cFYI(1, ("F_RDLCK"));
 623                 lockType |= LOCKING_ANDX_SHARED_LOCK;
 624                 numLock = 1;
 625         } else if (pfLock->fl_type == F_EXLCK) {
 626                 cFYI(1, ("F_EXLCK"));
 627                 numLock = 1;
 628         } else if (pfLock->fl_type == F_SHLCK) {
 629                 cFYI(1, ("F_SHLCK"));
 630                 lockType |= LOCKING_ANDX_SHARED_LOCK;
 631                 numLock = 1;
 632         } else
 633                 cFYI(1, ("Unknown type of lock"));
 634
 635         cifs_sb = CIFS_SB(file->f_dentry->d_sb);
 636         pTcon = cifs_sb->tcon;
 637
 638         if (file->private_data == NULL) {
 639                 FreeXid(xid);
 640                 return -EBADF;
 641         }
 642         netfid = ((struct cifsFileInfo *)file->private_data)->netfid;
 643
 644
 645         /* BB add code here to normalize offset and length to
 646         account for negative length which we can not accept over the
 647         wire */
 648         if (IS_GETLK(cmd)) {
 649                 if(experimEnabled &&
 650                    (cifs_sb->tcon->ses->capabilities & CAP_UNIX) &&
 651                    (CIFS_UNIX_FCNTL_CAP &
 652                         le64_to_cpu(cifs_sb->tcon->fsUnixInfo.Capability))) {
 653                         int posix_lock_type;
 654                         if(lockType & LOCKING_ANDX_SHARED_LOCK)
 655                                 posix_lock_type = CIFS_RDLCK;
 656                         else
 657                                 posix_lock_type = CIFS_WRLCK;
 658                         rc = CIFSSMBPosixLock(xid, pTcon, netfid, 1 /* get */,
 659                                         length, pfLock->fl_start,
 660                                         posix_lock_type, wait_flag);
 661                         FreeXid(xid);
 662                         return rc;
 663                 }
 664
 665                 /* BB we could chain these into one lock request BB */
 666                 rc = CIFSSMBLock(xid, pTcon, netfid, length, pfLock->fl_start,
 667                                  0, 1, lockType, 0 /* wait flag */ );
 668                 if (rc == 0) {
 669                         rc = CIFSSMBLock(xid, pTcon, netfid, length,
 670                                          pfLock->fl_start, 1 /* numUnlock */ ,
 671                                          0 /* numLock */ , lockType,
 672                                          0 /* wait flag */ );
 673                         pfLock->fl_type = F_UNLCK;
 674                         if (rc != 0)
 675                                 cERROR(1, ("Error unlocking previously locked "
 676                                            "range %d during test of lock", rc));
 677                         rc = 0;
 678
 679                 } else {
 680                         /* if rc == ERR_SHARING_VIOLATION ? */
 681                         rc = 0; /* do not change lock type to unlock
 682                                    since range in use */
 683                 }
 684
 685                 FreeXid(xid);
 686                 return rc;
 687         }
 688         if (experimEnabled &&
 689                 (cifs_sb->tcon->ses->capabilities & CAP_UNIX) &&
 690                 (CIFS_UNIX_FCNTL_CAP &
 691                          le64_to_cpu(cifs_sb->tcon->fsUnixInfo.Capability))) {
 692                 int posix_lock_type;
 693                 if(lockType & LOCKING_ANDX_SHARED_LOCK)
 694                         posix_lock_type = CIFS_RDLCK;
 695                 else
 696                         posix_lock_type = CIFS_WRLCK;
 697
 698                 if(numUnlock == 1)
 699                         posix_lock_type = CIFS_UNLCK;
 700                 else if(numLock == 0) {
 701                         /* if no lock or unlock then nothing
 702                         to do since we do not know what it is */
 703                         FreeXid(xid);
 704                         return -EOPNOTSUPP;
 705                 }
 706                 rc = CIFSSMBPosixLock(xid, pTcon, netfid, 0 /* set */,
 707                                       length, pfLock->fl_start,
 708                                       posix_lock_type, wait_flag);
 709         } else
 710                 rc = CIFSSMBLock(xid, pTcon, netfid, length, pfLock->fl_start,
 711                                 numUnlock, numLock, lockType, wait_flag);
 712         if (pfLock->fl_flags & FL_POSIX)
 713                 posix_lock_file_wait(file, pfLock);
 714         FreeXid(xid);
 715         return rc;
 716 }
 717
 718 ssize_t cifs_user_write(struct file *file, const char __user *write_data,
 719         size_t write_size, loff_t *poffset)
 720 {
 721         int rc = 0;
 722         unsigned int bytes_written = 0;
 723         unsigned int total_written;
 724         struct cifs_sb_info *cifs_sb;
 725         struct cifsTconInfo *pTcon;
 726         int xid, long_op;
 727         struct cifsFileInfo *open_file;
 728
 729         if (file->f_dentry == NULL)
 730                 return -EBADF;
 731
 732         cifs_sb = CIFS_SB(file->f_dentry->d_sb);
 733         if (cifs_sb == NULL)
 734                 return -EBADF;
 735
 736         pTcon = cifs_sb->tcon;
 737
 738         /* cFYI(1,
 739            (" write %d bytes to offset %lld of %s", write_size,
 740            *poffset, file->f_dentry->d_name.name)); */
 741
 742         if (file->private_data == NULL)
 743                 return -EBADF;
 744         else
 745                 open_file = (struct cifsFileInfo *) file->private_data;
 746
 747         xid = GetXid();
 748         if (file->f_dentry->d_inode == NULL) {
 749                 FreeXid(xid);
 750                 return -EBADF;
 751         }
 752
 753         if (*poffset > file->f_dentry->d_inode->i_size)
 754                 long_op = 2; /* writes past end of file can take a long time */
 755         else
 756                 long_op = 1;
 757
 758         for (total_written = 0; write_size > total_written;
 759              total_written += bytes_written) {
 760                 rc = -EAGAIN;
 761                 while (rc == -EAGAIN) {
 762                         if (file->private_data == NULL) {
 763                                 /* file has been closed on us */
 764                                 FreeXid(xid);
 765                         /* if we have gotten here we have written some data
 766                            and blocked, and the file has been freed on us while
 767                            we blocked so return what we managed to write */
 768                                 return total_written;
 769                         }
 770                         if (open_file->closePend) {
 771                                 FreeXid(xid);
 772                                 if (total_written)
 773                                         return total_written;
 774                                 else
 775                                         return -EBADF;
 776                         }
 777                         if (open_file->invalidHandle) {
 778                                 if ((file->f_dentry == NULL) ||
 779                                     (file->f_dentry->d_inode == NULL)) {
 780                                         FreeXid(xid);
 781                                         return total_written;
 782                                 }
 783                                 /* we could deadlock if we called
 784                                    filemap_fdatawait from here so tell
 785                                    reopen_file not to flush data to server
 786                                    now */
 787                                 rc = cifs_reopen_file(file->f_dentry->d_inode,
 788                                         file, FALSE);
 789                                 if (rc != 0)
 790                                         break;
 791                         }
 792
 793                         rc = CIFSSMBWrite(xid, pTcon,
 794                                 open_file->netfid,
 795                                 min_t(const int, cifs_sb->wsize,
 796                                       write_size - total_written),
 797                                 *poffset, &bytes_written,
 798                                 NULL, write_data + total_written, long_op);
 799                 }
 800                 if (rc || (bytes_written == 0)) {
 801                         if (total_written)
 802                                 break;
 803                         else {
 804                                 FreeXid(xid);
 805                                 return rc;
 806                         }
 807                 } else
 808                         *poffset += bytes_written;
 809                 long_op = FALSE; /* subsequent writes fast -
 810                                     15 seconds is plenty */
 811         }
 812
 813         cifs_stats_bytes_written(pTcon, total_written);
 814
 815         /* since the write may have blocked check these pointers again */
 816         if (file->f_dentry) {
 817                 if (file->f_dentry->d_inode) {
 818                         struct inode *inode = file->f_dentry->d_inode;
 819                         inode->i_ctime = inode->i_mtime =
 820                                 current_fs_time(inode->i_sb);
 821                         if (total_written > 0) {
 822                                 if (*poffset > file->f_dentry->d_inode->i_size)
 823                                         i_size_write(file->f_dentry->d_inode,
 824                                         *poffset);
 825                         }
 826                         mark_inode_dirty_sync(file->f_dentry->d_inode);
 827                 }
 828         }
 829         FreeXid(xid);
 830         return total_written;
 831 }
 832
 833 static ssize_t cifs_write(struct file *file, const char *write_data,
 834         size_t write_size, loff_t *poffset)
 835 {
 836         int rc = 0;
 837         unsigned int bytes_written = 0;
 838         unsigned int total_written;
 839         struct cifs_sb_info *cifs_sb;
 840         struct cifsTconInfo *pTcon;
 841         int xid, long_op;
 842         struct cifsFileInfo *open_file;
 843
 844         if (file->f_dentry == NULL)
 845                 return -EBADF;
 846
 847         cifs_sb = CIFS_SB(file->f_dentry->d_sb);
 848         if (cifs_sb == NULL)
 849                 return -EBADF;
 850
 851         pTcon = cifs_sb->tcon;
 852
 853         cFYI(1,("write %zd bytes to offset %lld of %s", write_size,
 854            *poffset, file->f_dentry->d_name.name));
 855
 856         if (file->private_data == NULL)
 857                 return -EBADF;
 858         else
 859                 open_file = (struct cifsFileInfo *)file->private_data;
 860
 861         xid = GetXid();
 862         if (file->f_dentry->d_inode == NULL) {
 863                 FreeXid(xid);
 864                 return -EBADF;
 865         }
 866
 867         if (*poffset > file->f_dentry->d_inode->i_size)
 868                 long_op = 2; /* writes past end of file can take a long time */
 869         else
 870                 long_op = 1;
 871
 872         for (total_written = 0; write_size > total_written;
 873              total_written += bytes_written) {
 874                 rc = -EAGAIN;
 875                 while (rc == -EAGAIN) {
 876                         if (file->private_data == NULL) {
 877                                 /* file has been closed on us */
 878                                 FreeXid(xid);
 879                         /* if we have gotten here we have written some data
 880                            and blocked, and the file has been freed on us
 881                            while we blocked so return what we managed to
 882                            write */
 883                                 return total_written;
 884                         }
 885                         if (open_file->closePend) {
 886                                 FreeXid(xid);
 887                                 if (total_written)
 888                                         return total_written;
 889                                 else
 890                                         return -EBADF;
 891                         }
 892                         if (open_file->invalidHandle) {
 893                                 if ((file->f_dentry == NULL) ||
 894                                    (file->f_dentry->d_inode == NULL)) {
 895                                         FreeXid(xid);
 896                                         return total_written;
 897                                 }
 898                                 /* we could deadlock if we called
 899                                    filemap_fdatawait from here so tell
 900                                    reopen_file not to flush data to
 901                                    server now */
 902                                 rc = cifs_reopen_file(file->f_dentry->d_inode,
 903                                         file, FALSE);
 904                                 if (rc != 0)
 905                                         break;
 906                         }
 907                         /* BB FIXME We can not sign across two buffers yet */
 908                         if((pTcon->ses->server->secMode &
 909                          (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) == 0) {
 910                                 struct kvec iov[2];
 911                                 unsigned int len;
 912
 913                                 len = min((size_t)cifs_sb->wsize,
 914                                           write_size - total_written);
 915                                 /* iov[0] is reserved for smb header */
 916                                 iov[1].iov_base = (char *)write_data +
 917                                                   total_written;
 918                                 iov[1].iov_len = len;
 919                                 rc = CIFSSMBWrite2(xid, pTcon,
 920                                                 open_file->netfid, len,
 921                                                 *poffset, &bytes_written,
 922                                                 iov, 1, long_op);
 923                         } else
 924                         /* BB FIXME fixup indentation of line below */
 925                         rc = CIFSSMBWrite(xid, pTcon,
 926                                  open_file->netfid,
 927                                  min_t(const int, cifs_sb->wsize,
 928                                        write_size - total_written),
 929                                  *poffset, &bytes_written,
 930                                  write_data + total_written, NULL, long_op);
 931                 }
 932                 if (rc || (bytes_written == 0)) {
 933                         if (total_written)
 934                                 break;
 935                         else {
 936                                 FreeXid(xid);
 937                                 return rc;
 938                         }
 939                 } else
 940                         *poffset += bytes_written;
 941                 long_op = FALSE; /* subsequent writes fast -
 942                                     15 seconds is plenty */
 943         }
 944
 945         cifs_stats_bytes_written(pTcon, total_written);
 946
 947         /* since the write may have blocked check these pointers again */
 948         if (file->f_dentry) {
 949                 if (file->f_dentry->d_inode) {
 950                         file->f_dentry->d_inode->i_ctime =
 951                         file->f_dentry->d_inode->i_mtime = CURRENT_TIME;
 952                         if (total_written > 0) {
 953                                 if (*poffset > file->f_dentry->d_inode->i_size)
 954                                         i_size_write(file->f_dentry->d_inode,
 955                                                      *poffset);
 956                         }
 957                         mark_inode_dirty_sync(file->f_dentry->d_inode);
 958                 }
 959         }
 960         FreeXid(xid);
 961         return total_written;
 962 }
 963
 964 struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode)
 965 {
 966         struct cifsFileInfo *open_file;
 967         int rc;
 968
 969         read_lock(&GlobalSMBSeslock);
 970         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
 971                 if (open_file->closePend)
 972                         continue;
 973                 if (open_file->pfile &&
 974                     ((open_file->pfile->f_flags & O_RDWR) ||
 975                      (open_file->pfile->f_flags & O_WRONLY))) {
 976                         atomic_inc(&open_file->wrtPending);
 977                         read_unlock(&GlobalSMBSeslock);
 978                         if((open_file->invalidHandle) &&
 979                            (!open_file->closePend) /* BB fixme -since the second clause can not be true remove it BB */) {
 980                                 rc = cifs_reopen_file(&cifs_inode->vfs_inode,
 981                                                       open_file->pfile, FALSE);
 982                                 /* if it fails, try another handle - might be */
 983                                 /* dangerous to hold up writepages with retry */
 984                                 if(rc) {
 985                                         cFYI(1,("failed on reopen file in wp"));
 986                                         read_lock(&GlobalSMBSeslock);
 987                                         /* can not use this handle, no write
 988                                         pending on this one after all */
 989                                         atomic_dec
 990                                              (&open_file->wrtPending);
 991                                         continue;
 992                                 }
 993                         }
 994                         return open_file;
 995                 }
 996         }
 997         read_unlock(&GlobalSMBSeslock);
 998         return NULL;
 999 }
1000
1001 static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
1002 {
1003         struct address_space *mapping = page->mapping;
1004         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1005         char *write_data;
1006         int rc = -EFAULT;
1007         int bytes_written = 0;
1008         struct cifs_sb_info *cifs_sb;
1009         struct cifsTconInfo *pTcon;
1010         struct inode *inode;
1011         struct cifsFileInfo *open_file;
1012
1013         if (!mapping || !mapping->host)
1014                 return -EFAULT;
1015
1016         inode = page->mapping->host;
1017         cifs_sb = CIFS_SB(inode->i_sb);
1018         pTcon = cifs_sb->tcon;
1019
1020         offset += (loff_t)from;
1021         write_data = kmap(page);
1022         write_data += from;
1023
1024         if ((to > PAGE_CACHE_SIZE) || (from > to)) {
1025                 kunmap(page);
1026                 return -EIO;
1027         }
1028
1029         /* racing with truncate? */
1030         if (offset > mapping->host->i_size) {
1031                 kunmap(page);
1032                 return 0; /* don't care */
1033         }
1034
1035         /* check to make sure that we are not extending the file */
1036         if (mapping->host->i_size - offset < (loff_t)to)
1037                 to = (unsigned)(mapping->host->i_size - offset);
1038
1039         open_file = find_writable_file(CIFS_I(mapping->host));
1040         if (open_file) {
1041                 bytes_written = cifs_write(open_file->pfile, write_data,
1042                                            to-from, &offset);
1043                 atomic_dec(&open_file->wrtPending);
1044                 /* Does mm or vfs already set times? */
1045                 inode->i_atime = inode->i_mtime = current_fs_time(inode->i_sb);
1046                 if ((bytes_written > 0) && (offset)) {
1047                         rc = 0;
1048                 } else if (bytes_written < 0) {
1049                         if (rc != -EBADF)
1050                                 rc = bytes_written;
1051                 }
1052         } else {
1053                 cFYI(1, ("No writeable filehandles for inode"));
1054                 rc = -EIO;
1055         }
1056
1057         kunmap(page);
1058         return rc;
1059 }
1060
1061 static int cifs_writepages(struct address_space *mapping,
1062                            struct writeback_control *wbc)
1063 {
1064         struct backing_dev_info *bdi = mapping->backing_dev_info;
1065         unsigned int bytes_to_write;
1066         unsigned int bytes_written;
1067         struct cifs_sb_info *cifs_sb;
1068         int done = 0;
1069         pgoff_t end = -1;
1070         pgoff_t index;
1071         int is_range = 0;
1072         struct kvec iov[32];
1073         int len;
1074         int n_iov = 0;
1075         pgoff_t next;
1076         int nr_pages;
1077         __u64 offset = 0;
1078         struct cifsFileInfo *open_file;
1079         struct page *page;
1080         struct pagevec pvec;
1081         int rc = 0;
1082         int scanned = 0;
1083         int xid;
1084
1085         cifs_sb = CIFS_SB(mapping->host->i_sb);
1086
1087         /*
1088          * If wsize is smaller that the page cache size, default to writing
1089          * one page at a time via cifs_writepage
1090          */
1091         if (cifs_sb->wsize < PAGE_CACHE_SIZE)
1092                 return generic_writepages(mapping, wbc);
1093
1094         /* BB FIXME we do not have code to sign across multiple buffers yet,
1095            so go to older writepage style write which we can sign if needed */
1096         if((cifs_sb->tcon->ses) && (cifs_sb->tcon->ses->server))
1097                 if(cifs_sb->tcon->ses->server->secMode &
1098                           (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
1099                         return generic_writepages(mapping, wbc);
1100
1101         /*
1102          * BB: Is this meaningful for a non-block-device file system?
1103          * If it is, we should test it again after we do I/O
1104          */
1105         if (wbc->nonblocking && bdi_write_congested(bdi)) {
1106                 wbc->encountered_congestion = 1;
1107                 return 0;
1108         }
1109
1110         xid = GetXid();
1111
1112         pagevec_init(&pvec, 0);
1113         if (wbc->sync_mode == WB_SYNC_NONE)
1114                 index = mapping->writeback_index; /* Start from prev offset */
1115         else {
1116                 index = 0;
1117                 scanned = 1;
1118         }
1119         if (wbc->start || wbc->end) {
1120                 index = wbc->start >> PAGE_CACHE_SHIFT;
1121                 end = wbc->end >> PAGE_CACHE_SHIFT;
1122                 is_range = 1;
1123                 scanned = 1;
1124         }
1125 retry:
1126         while (!done && (index <= end) &&
1127                (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
1128                         PAGECACHE_TAG_DIRTY,
1129                         min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1))) {
1130                 int first;
1131                 unsigned int i;
1132
1133                 first = -1;
1134                 next = 0;
1135                 n_iov = 0;
1136                 bytes_to_write = 0;
1137
1138                 for (i = 0; i < nr_pages; i++) {
1139                         page = pvec.pages[i];
1140                         /*
1141                          * At this point we hold neither mapping->tree_lock nor
1142                          * lock on the page itself: the page may be truncated or
1143                          * invalidated (changing page->mapping to NULL), or even
1144                          * swizzled back from swapper_space to tmpfs file
1145                          * mapping
1146                          */
1147
1148                         if (first < 0)
1149                                 lock_page(page);
1150                         else if (TestSetPageLocked(page))
1151                                 break;
1152
1153                         if (unlikely(page->mapping != mapping)) {
1154                                 unlock_page(page);
1155                                 break;
1156                         }
1157
1158                         if (unlikely(is_range) && (page->index > end)) {
1159                                 done = 1;
1160                                 unlock_page(page);
1161                                 break;
1162                         }
1163
1164                         if (next && (page->index != next)) {
1165                                 /* Not next consecutive page */
1166                                 unlock_page(page);
1167                                 break;
1168                         }
1169
1170                         if (wbc->sync_mode != WB_SYNC_NONE)
1171                                 wait_on_page_writeback(page);
1172
1173                         if (PageWriteback(page) ||
1174                                         !test_clear_page_dirty(page)) {
1175                                 unlock_page(page);
1176                                 break;
1177                         }
1178
1179                         if (page_offset(page) >= mapping->host->i_size) {
1180                                 done = 1;
1181                                 unlock_page(page);
1182                                 break;
1183                         }
1184
1185                         /*
1186                          * BB can we get rid of this?  pages are held by pvec
1187                          */
1188                         page_cache_get(page);
1189
1190                         len = min(mapping->host->i_size - page_offset(page),
1191                                   (loff_t)PAGE_CACHE_SIZE);
1192
1193                         /* reserve iov[0] for the smb header */
1194                         n_iov++;
1195                         iov[n_iov].iov_base = kmap(page);
1196                         iov[n_iov].iov_len = len;
1197                         bytes_to_write += len;
1198
1199                         if (first < 0) {
1200                                 first = i;
1201                                 offset = page_offset(page);
1202                         }
1203                         next = page->index + 1;
1204                         if (bytes_to_write + PAGE_CACHE_SIZE > cifs_sb->wsize)
1205                                 break;
1206                 }
1207                 if (n_iov) {
1208                         /* Search for a writable handle every time we call
1209                          * CIFSSMBWrite2.  We can't rely on the last handle
1210                          * we used to still be valid
1211                          */
1212                         open_file = find_writable_file(CIFS_I(mapping->host));
1213                         if (!open_file) {
1214                                 cERROR(1, ("No writable handles for inode"));
1215                                 rc = -EBADF;
1216                         } else {
1217                                 rc = CIFSSMBWrite2(xid, cifs_sb->tcon,
1218                                                    open_file->netfid,
1219                                                    bytes_to_write, offset,
1220                                                    &bytes_written, iov, n_iov,
1221                                                    1);
1222                                 atomic_dec(&open_file->wrtPending);
1223                                 if (rc || bytes_written < bytes_to_write) {
1224                                         cERROR(1,("Write2 ret %d, written = %d",
1225                                                   rc, bytes_written));
1226                                         /* BB what if continued retry is
1227                                            requested via mount flags? */
1228                                         set_bit(AS_EIO, &mapping->flags);
1229                                 } else {
1230                                         cifs_stats_bytes_written(cifs_sb->tcon,
1231                                                                  bytes_written);
1232                                 }
1233                         }
1234                         for (i = 0; i < n_iov; i++) {
1235                                 page = pvec.pages[first + i];
1236                                 /* Should we also set page error on
1237                                 success rc but too little data written? */
1238                                 /* BB investigate retry logic on temporary
1239                                 server crash cases and how recovery works
1240                                 when page marked as error */
1241                                 if(rc)
1242                                         SetPageError(page);
1243                                 kunmap(page);
1244                                 unlock_page(page);
1245                                 page_cache_release(page);
1246                         }
1247                         if ((wbc->nr_to_write -= n_iov) <= 0)
1248                                 done = 1;
1249                         index = next;
1250                 }
1251                 pagevec_release(&pvec);
1252         }
1253         if (!scanned && !done) {
1254                 /*
1255                  * We hit the last page and there is more work to be done: wrap
1256                  * back to the start of the file
1257                  */
1258                 scanned = 1;
1259                 index = 0;
1260                 goto retry;
1261         }
1262         if (!is_range)
1263                 mapping->writeback_index = index;
1264
1265         FreeXid(xid);
1266
1267         return rc;
1268 }
1269
1270 static int cifs_writepage(struct page* page, struct writeback_control *wbc)
1271 {
1272         int rc = -EFAULT;
1273         int xid;
1274
1275         xid = GetXid();
1276 /* BB add check for wbc flags */
1277         page_cache_get(page);
1278         if (!PageUptodate(page)) {
1279                 cFYI(1, ("ppw - page not up to date"));
1280         }
1281
1282         rc = cifs_partialpagewrite(page, 0, PAGE_CACHE_SIZE);
1283         SetPageUptodate(page); /* BB add check for error and Clearuptodate? */
1284         unlock_page(page);
1285         page_cache_release(page);
1286         FreeXid(xid);
1287         return rc;
1288 }
1289
1290 static int cifs_commit_write(struct file *file, struct page *page,
1291         unsigned offset, unsigned to)
1292 {
1293         int xid;
1294         int rc = 0;
1295         struct inode *inode = page->mapping->host;
1296         loff_t position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
1297         char *page_data;
1298
1299         xid = GetXid();
1300         cFYI(1, ("commit write for page %p up to position %lld for %d",
1301                  page, position, to));
1302         if (position > inode->i_size) {
1303                 i_size_write(inode, position);
1304                 /* if (file->private_data == NULL) {
1305                         rc = -EBADF;
1306                 } else {
1307                         open_file = (struct cifsFileInfo *)file->private_data;
1308                         cifs_sb = CIFS_SB(inode->i_sb);
1309                         rc = -EAGAIN;
1310                         while (rc == -EAGAIN) {
1311                                 if ((open_file->invalidHandle) &&
1312                                     (!open_file->closePend)) {
1313                                         rc = cifs_reopen_file(
1314                                                 file->f_dentry->d_inode, file);
1315                                         if (rc != 0)
1316                                                 break;
1317                                 }
1318                                 if (!open_file->closePend) {
1319                                         rc = CIFSSMBSetFileSize(xid,
1320                                                 cifs_sb->tcon, position,
1321                                                 open_file->netfid,
1322                                                 open_file->pid, FALSE);
1323                                 } else {
1324                                         rc = -EBADF;
1325                                         break;
1326                                 }
1327                         }
1328                         cFYI(1, (" SetEOF (commit write) rc = %d", rc));
1329                 } */
1330         }
1331         if (!PageUptodate(page)) {
1332                 position =  ((loff_t)page->index << PAGE_CACHE_SHIFT) + offset;
1333                 /* can not rely on (or let) writepage write this data */
1334                 if (to < offset) {
1335                         cFYI(1, ("Illegal offsets, can not copy from %d to %d",
1336                                 offset, to));
1337                         FreeXid(xid);
1338                         return rc;
1339                 }
1340                 /* this is probably better than directly calling
1341                    partialpage_write since in this function the file handle is
1342                    known which we might as well leverage */
1343                 /* BB check if anything else missing out of ppw
1344                    such as updating last write time */
1345                 page_data = kmap(page);
1346                 rc = cifs_write(file, page_data + offset, to-offset,
1347                                 &position);
1348                 if (rc > 0)
1349                         rc = 0;
1350                 /* else if (rc < 0) should we set writebehind rc? */
1351                 kunmap(page);
1352         } else {
1353                 set_page_dirty(page);
1354         }
1355
1356         FreeXid(xid);
1357         return rc;
1358 }
1359
1360 int cifs_fsync(struct file *file, struct dentry *dentry, int datasync)
1361 {
1362         int xid;
1363         int rc = 0;
1364         struct inode *inode = file->f_dentry->d_inode;
1365
1366         xid = GetXid();
1367
1368         cFYI(1, ("Sync file - name: %s datasync: 0x%x ",
1369                 dentry->d_name.name, datasync));
1370
1371         rc = filemap_fdatawrite(inode->i_mapping);
1372         if (rc == 0)
1373                 CIFS_I(inode)->write_behind_rc = 0;
1374         FreeXid(xid);
1375         return rc;
1376 }
1377
1378 /* static void cifs_sync_page(struct page *page)
1379 {
1380         struct address_space *mapping;
1381         struct inode *inode;
1382         unsigned long index = page->index;
1383         unsigned int rpages = 0;
1384         int rc = 0;
1385
1386         cFYI(1, ("sync page %p",page));
1387         mapping = page->mapping;
1388         if (!mapping)
1389                 return 0;
1390         inode = mapping->host;
1391         if (!inode)
1392                 return; */
1393
1394 /*      fill in rpages then
1395         result = cifs_pagein_inode(inode, index, rpages); */ /* BB finish */
1396
1397 /*      cFYI(1, ("rpages is %d for sync page of Index %ld ", rpages, index));
1398
1399 #if 0
1400         if (rc < 0)
1401                 return rc;
1402         return 0;
1403 #endif
1404 } */
1405
1406 /*
1407  * As file closes, flush all cached write data for this inode checking
1408  * for write behind errors.
1409  */
1410 int cifs_flush(struct file *file)
1411 {
1412         struct inode * inode = file->f_dentry->d_inode;
1413         int rc = 0;
1414
1415         /* Rather than do the steps manually:
1416            lock the inode for writing
1417            loop through pages looking for write behind data (dirty pages)
1418            coalesce into contiguous 16K (or smaller) chunks to write to server
1419            send to server (prefer in parallel)
1420            deal with writebehind errors
1421            unlock inode for writing
1422            filemapfdatawrite appears easier for the time being */
1423
1424         rc = filemap_fdatawrite(inode->i_mapping);
1425         if (!rc) /* reset wb rc if we were able to write out dirty pages */
1426                 CIFS_I(inode)->write_behind_rc = 0;
1427
1428         cFYI(1, ("Flush inode %p file %p rc %d",inode,file,rc));
1429
1430         return rc;
1431 }
1432
1433 ssize_t cifs_user_read(struct file *file, char __user *read_data,
1434         size_t read_size, loff_t *poffset)
1435 {
1436         int rc = -EACCES;
1437         unsigned int bytes_read = 0;
1438         unsigned int total_read = 0;
1439         unsigned int current_read_size;
1440         struct cifs_sb_info *cifs_sb;
1441         struct cifsTconInfo *pTcon;
1442         int xid;
1443         struct cifsFileInfo *open_file;
1444         char *smb_read_data;
1445         char __user *current_offset;
1446         struct smb_com_read_rsp *pSMBr;
1447
1448         xid = GetXid();
1449         cifs_sb = CIFS_SB(file->f_dentry->d_sb);
1450         pTcon = cifs_sb->tcon;
1451
1452         if (file->private_data == NULL) {
1453                 FreeXid(xid);
1454                 return -EBADF;
1455         }
1456         open_file = (struct cifsFileInfo *)file->private_data;
1457
1458         if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
1459                 cFYI(1, ("attempting read on write only file instance"));
1460         }
1461         for (total_read = 0, current_offset = read_data;
1462              read_size > total_read;
1463              total_read += bytes_read, current_offset += bytes_read) {
1464                 current_read_size = min_t(const int, read_size - total_read,
1465                                           cifs_sb->rsize);
1466                 rc = -EAGAIN;
1467                 smb_read_data = NULL;
1468                 while (rc == -EAGAIN) {
1469                         int buf_type = CIFS_NO_BUFFER;
1470                         if ((open_file->invalidHandle) &&
1471                             (!open_file->closePend)) {
1472                                 rc = cifs_reopen_file(file->f_dentry->d_inode,
1473                                         file, TRUE);
1474                                 if (rc != 0)
1475                                         break;
1476                         }
1477                         rc = CIFSSMBRead(xid, pTcon,
1478                                          open_file->netfid,
1479                                          current_read_size, *poffset,
1480                                          &bytes_read, &smb_read_data,
1481                                          &buf_type);
1482                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
1483                         if (smb_read_data) {
1484                                 if (copy_to_user(current_offset,
1485                                                 smb_read_data +
1486                                                 4 /* RFC1001 length field */ +
1487                                                 le16_to_cpu(pSMBr->DataOffset),
1488                                                 bytes_read)) {
1489                                         rc = -EFAULT;
1490                                 }
1491
1492                                 if(buf_type == CIFS_SMALL_BUFFER)
1493                                         cifs_small_buf_release(smb_read_data);
1494                                 else if(buf_type == CIFS_LARGE_BUFFER)
1495                                         cifs_buf_release(smb_read_data);
1496                                 smb_read_data = NULL;
1497                         }
1498                 }
1499                 if (rc || (bytes_read == 0)) {
1500                         if (total_read) {
1501                                 break;
1502                         } else {
1503                                 FreeXid(xid);
1504                                 return rc;
1505                         }
1506                 } else {
1507                         cifs_stats_bytes_read(pTcon, bytes_read);
1508                         *poffset += bytes_read;
1509                 }
1510         }
1511         FreeXid(xid);
1512         return total_read;
1513 }
1514
1515
1516 static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
1517         loff_t *poffset)
1518 {
1519         int rc = -EACCES;
1520         unsigned int bytes_read = 0;
1521         unsigned int total_read;
1522         unsigned int current_read_size;
1523         struct cifs_sb_info *cifs_sb;
1524         struct cifsTconInfo *pTcon;
1525         int xid;
1526         char *current_offset;
1527         struct cifsFileInfo *open_file;
1528         int buf_type = CIFS_NO_BUFFER;
1529
1530         xid = GetXid();
1531         cifs_sb = CIFS_SB(file->f_dentry->d_sb);
1532         pTcon = cifs_sb->tcon;
1533
1534         if (file->private_data == NULL) {
1535                 FreeXid(xid);
1536                 return -EBADF;
1537         }
1538         open_file = (struct cifsFileInfo *)file->private_data;
1539
1540         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
1541                 cFYI(1, ("attempting read on write only file instance"));
1542
1543         for (total_read = 0, current_offset = read_data;
1544              read_size > total_read;
1545              total_read += bytes_read, current_offset += bytes_read) {
1546                 current_read_size = min_t(const int, read_size - total_read,
1547                                           cifs_sb->rsize);
1548                 /* For windows me and 9x we do not want to request more
1549                 than it negotiated since it will refuse the read then */
1550                 if((pTcon->ses) &&
1551                         !(pTcon->ses->capabilities & CAP_LARGE_FILES)) {
1552                         current_read_size = min_t(const int, current_read_size,
1553                                         pTcon->ses->server->maxBuf - 128);
1554                 }
1555                 rc = -EAGAIN;
1556                 while (rc == -EAGAIN) {
1557                         if ((open_file->invalidHandle) &&
1558                             (!open_file->closePend)) {
1559                                 rc = cifs_reopen_file(file->f_dentry->d_inode,
1560                                         file, TRUE);
1561                                 if (rc != 0)
1562                                         break;
1563                         }
1564                         rc = CIFSSMBRead(xid, pTcon,
1565                                          open_file->netfid,
1566                                          current_read_size, *poffset,
1567                                          &bytes_read, &current_offset,
1568                                          &buf_type);
1569                 }
1570                 if (rc || (bytes_read == 0)) {
1571                         if (total_read) {
1572                                 break;
1573                         } else {
1574                                 FreeXid(xid);
1575                                 return rc;
1576                         }
1577                 } else {
1578                         cifs_stats_bytes_read(pTcon, total_read);
1579                         *poffset += bytes_read;
1580                 }
1581         }
1582         FreeXid(xid);
1583         return total_read;
1584 }
1585
1586 int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
1587 {
1588         struct dentry *dentry = file->f_dentry;
1589         int rc, xid;
1590
1591         xid = GetXid();
1592         rc = cifs_revalidate(dentry);
1593         if (rc) {
1594                 cFYI(1, ("Validation prior to mmap failed, error=%d", rc));
1595                 FreeXid(xid);
1596                 return rc;
1597         }
1598         rc = generic_file_mmap(file, vma);
1599         FreeXid(xid);
1600         return rc;
1601 }
1602
1603
1604 static void cifs_copy_cache_pages(struct address_space *mapping,
1605         struct list_head *pages, int bytes_read, char *data,
1606         struct pagevec *plru_pvec)
1607 {
1608         struct page *page;
1609         char *target;
1610
1611         while (bytes_read > 0) {
1612                 if (list_empty(pages))
1613                         break;
1614
1615                 page = list_entry(pages->prev, struct page, lru);
1616                 list_del(&page->lru);
1617
1618                 if (add_to_page_cache(page, mapping, page->index,
1619                                       GFP_KERNEL)) {
1620                         page_cache_release(page);
1621                         cFYI(1, ("Add page cache failed"));
1622                         data += PAGE_CACHE_SIZE;
1623                         bytes_read -= PAGE_CACHE_SIZE;
1624                         continue;
1625                 }
1626
1627                 target = kmap_atomic(page,KM_USER0);
1628
1629                 if (PAGE_CACHE_SIZE > bytes_read) {
1630                         memcpy(target, data, bytes_read);
1631                         /* zero the tail end of this partial page */
1632                         memset(target + bytes_read, 0,
1633                                PAGE_CACHE_SIZE - bytes_read);
1634                         bytes_read = 0;
1635                 } else {
1636                         memcpy(target, data, PAGE_CACHE_SIZE);
1637                         bytes_read -= PAGE_CACHE_SIZE;
1638                 }
1639                 kunmap_atomic(target, KM_USER0);
1640
1641                 flush_dcache_page(page);
1642                 SetPageUptodate(page);
1643                 unlock_page(page);
1644                 if (!pagevec_add(plru_pvec, page))
1645                         __pagevec_lru_add(plru_pvec);
1646                 data += PAGE_CACHE_SIZE;
1647         }
1648         return;
1649 }
1650
1651 static int cifs_readpages(struct file *file, struct address_space *mapping,
1652         struct list_head *page_list, unsigned num_pages)
1653 {
1654         int rc = -EACCES;
1655         int xid;
1656         loff_t offset;
1657         struct page *page;
1658         struct cifs_sb_info *cifs_sb;
1659         struct cifsTconInfo *pTcon;
1660         int bytes_read = 0;
1661         unsigned int read_size,i;
1662         char *smb_read_data = NULL;
1663         struct smb_com_read_rsp *pSMBr;
1664         struct pagevec lru_pvec;
1665         struct cifsFileInfo *open_file;
1666         int buf_type = CIFS_NO_BUFFER;
1667
1668         xid = GetXid();
1669         if (file->private_data == NULL) {
1670                 FreeXid(xid);
1671                 return -EBADF;
1672         }
1673         open_file = (struct cifsFileInfo *)file->private_data;
1674         cifs_sb = CIFS_SB(file->f_dentry->d_sb);
1675         pTcon = cifs_sb->tcon;
1676
1677         pagevec_init(&lru_pvec, 0);
1678
1679         for (i = 0; i < num_pages; ) {
1680                 unsigned contig_pages;
1681                 struct page *tmp_page;
1682                 unsigned long expected_index;
1683
1684                 if (list_empty(page_list))
1685                         break;
1686
1687                 page = list_entry(page_list->prev, struct page, lru);
1688                 offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1689
1690                 /* count adjacent pages that we will read into */
1691                 contig_pages = 0;
1692                 expected_index =
1693                         list_entry(page_list->prev, struct page, lru)->index;
1694                 list_for_each_entry_reverse(tmp_page,page_list,lru) {
1695                         if (tmp_page->index == expected_index) {
1696                                 contig_pages++;
1697                                 expected_index++;
1698                         } else
1699                                 break;
1700                 }
1701                 if (contig_pages + i >  num_pages)
1702                         contig_pages = num_pages - i;
1703
1704                 /* for reads over a certain size could initiate async
1705                    read ahead */
1706
1707                 read_size = contig_pages * PAGE_CACHE_SIZE;
1708                 /* Read size needs to be in multiples of one page */
1709                 read_size = min_t(const unsigned int, read_size,
1710                                   cifs_sb->rsize & PAGE_CACHE_MASK);
1711
1712                 rc = -EAGAIN;
1713                 while (rc == -EAGAIN) {
1714                         if ((open_file->invalidHandle) &&
1715                             (!open_file->closePend)) {
1716                                 rc = cifs_reopen_file(file->f_dentry->d_inode,
1717                                         file, TRUE);
1718                                 if (rc != 0)
1719                                         break;
1720                         }
1721
1722                         rc = CIFSSMBRead(xid, pTcon,
1723                                          open_file->netfid,
1724                                          read_size, offset,
1725                                          &bytes_read, &smb_read_data,
1726                                          &buf_type);
1727                         /* BB more RC checks ? */
1728                         if (rc== -EAGAIN) {
1729                                 if (smb_read_data) {
1730                                         if(buf_type == CIFS_SMALL_BUFFER)
1731                                                 cifs_small_buf_release(smb_read_data);
1732                                         else if(buf_type == CIFS_LARGE_BUFFER)
1733                                                 cifs_buf_release(smb_read_data);
1734                                         smb_read_data = NULL;
1735                                 }
1736                         }
1737                 }
1738                 if ((rc < 0) || (smb_read_data == NULL)) {
1739                         cFYI(1, ("Read error in readpages: %d", rc));
1740                         /* clean up remaing pages off list */
1741                         while (!list_empty(page_list) && (i < num_pages)) {
1742                                 page = list_entry(page_list->prev, struct page,
1743                                                   lru);
1744                                 list_del(&page->lru);
1745                                 page_cache_release(page);
1746                         }
1747                         break;
1748                 } else if (bytes_read > 0) {
1749                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
1750                         cifs_copy_cache_pages(mapping, page_list, bytes_read,
1751                                 smb_read_data + 4 /* RFC1001 hdr */ +
1752                                 le16_to_cpu(pSMBr->DataOffset), &lru_pvec);
1753
1754                         i +=  bytes_read >> PAGE_CACHE_SHIFT;
1755                         cifs_stats_bytes_read(pTcon, bytes_read);
1756                         if ((int)(bytes_read & PAGE_CACHE_MASK) != bytes_read) {
1757                                 i++; /* account for partial page */
1758
1759                                 /* server copy of file can have smaller size
1760                                    than client */
1761                                 /* BB do we need to verify this common case ?
1762                                    this case is ok - if we are at server EOF
1763                                    we will hit it on next read */
1764
1765                         /* while (!list_empty(page_list) && (i < num_pages)) {
1766                                         page = list_entry(page_list->prev,
1767                                                           struct page, list);
1768                                         list_del(&page->list);
1769                                         page_cache_release(page);
1770                                 }
1771                                 break; */
1772                         }
1773                 } else {
1774                         cFYI(1, ("No bytes read (%d) at offset %lld . "
1775                                  "Cleaning remaining pages from readahead list",
1776                                  bytes_read, offset));
1777                         /* BB turn off caching and do new lookup on
1778                            file size at server? */
1779                         while (!list_empty(page_list) && (i < num_pages)) {
1780                                 page = list_entry(page_list->prev, struct page,
1781                                                   lru);
1782                                 list_del(&page->lru);
1783
1784                                 /* BB removeme - replace with zero of page? */
1785                                 page_cache_release(page);
1786                         }
1787                         break;
1788                 }
1789                 if (smb_read_data) {
1790                         if(buf_type == CIFS_SMALL_BUFFER)
1791                                 cifs_small_buf_release(smb_read_data);
1792                         else if(buf_type == CIFS_LARGE_BUFFER)
1793                                 cifs_buf_release(smb_read_data);
1794                         smb_read_data = NULL;
1795                 }
1796                 bytes_read = 0;
1797         }
1798
1799         pagevec_lru_add(&lru_pvec);
1800
1801 /* need to free smb_read_data buf before exit */
1802         if (smb_read_data) {
1803                 if(buf_type == CIFS_SMALL_BUFFER)
1804                         cifs_small_buf_release(smb_read_data);
1805                 else if(buf_type == CIFS_LARGE_BUFFER)
1806                         cifs_buf_release(smb_read_data);
1807                 smb_read_data = NULL;
1808         }
1809
1810         FreeXid(xid);
1811         return rc;
1812 }
1813
1814 static int cifs_readpage_worker(struct file *file, struct page *page,
1815         loff_t *poffset)
1816 {
1817         char *read_data;
1818         int rc;
1819
1820         page_cache_get(page);
1821         read_data = kmap(page);
1822         /* for reads over a certain size could initiate async read ahead */
1823
1824         rc = cifs_read(file, read_data, PAGE_CACHE_SIZE, poffset);
1825
1826         if (rc < 0)
1827                 goto io_error;
1828         else
1829                 cFYI(1, ("Bytes read %d ",rc));
1830
1831         file->f_dentry->d_inode->i_atime =
1832                 current_fs_time(file->f_dentry->d_inode->i_sb);
1833
1834         if (PAGE_CACHE_SIZE > rc)
1835                 memset(read_data + rc, 0, PAGE_CACHE_SIZE - rc);
1836
1837         flush_dcache_page(page);
1838         SetPageUptodate(page);
1839         rc = 0;
1840
1841 io_error:
1842         kunmap(page);
1843         page_cache_release(page);
1844         return rc;
1845 }
1846
1847 static int cifs_readpage(struct file *file, struct page *page)
1848 {
1849         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1850         int rc = -EACCES;
1851         int xid;
1852
1853         xid = GetXid();
1854
1855         if (file->private_data == NULL) {
1856                 FreeXid(xid);
1857                 return -EBADF;
1858         }
1859
1860         cFYI(1, ("readpage %p at offset %d 0x%x\n",
1861                  page, (int)offset, (int)offset));
1862
1863         rc = cifs_readpage_worker(file, page, &offset);
1864
1865         unlock_page(page);
1866
1867         FreeXid(xid);
1868         return rc;
1869 }
1870
1871 /* We do not want to update the file size from server for inodes
1872    open for write - to avoid races with writepage extending
1873    the file - in the future we could consider allowing
1874    refreshing the inode only on increases in the file size
1875    but this is tricky to do without racing with writebehind
1876    page caching in the current Linux kernel design */
1877 int is_size_safe_to_change(struct cifsInodeInfo *cifsInode)
1878 {
1879         struct cifsFileInfo *open_file = NULL;
1880
1881         if (cifsInode)
1882                 open_file =  find_writable_file(cifsInode);
1883
1884         if(open_file) {
1885                 struct cifs_sb_info *cifs_sb;
1886
1887                 /* there is not actually a write pending so let
1888                 this handle go free and allow it to
1889                 be closable if needed */
1890                 atomic_dec(&open_file->wrtPending);
1891
1892                 cifs_sb = CIFS_SB(cifsInode->vfs_inode.i_sb);
1893                 if ( cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO ) {
1894                         /* since no page cache to corrupt on directio
1895                         we can change size safely */
1896                         return 1;
1897                 }
1898
1899                 return 0;
1900         } else
1901                 return 1;
1902 }
1903
1904 static int cifs_prepare_write(struct file *file, struct page *page,
1905         unsigned from, unsigned to)
1906 {
1907         int rc = 0;
1908         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1909         cFYI(1, ("prepare write for page %p from %d to %d",page,from,to));
1910         if (!PageUptodate(page)) {
1911         /*      if (to - from != PAGE_CACHE_SIZE) {
1912                         void *kaddr = kmap_atomic(page, KM_USER0);
1913                         memset(kaddr, 0, from);
1914                         memset(kaddr + to, 0, PAGE_CACHE_SIZE - to);
1915                         flush_dcache_page(page);
1916                         kunmap_atomic(kaddr, KM_USER0);
1917                 } */
1918                 /* If we are writing a full page it will be up to date,
1919                    no need to read from the server */
1920                 if ((to == PAGE_CACHE_SIZE) && (from == 0))
1921                         SetPageUptodate(page);
1922
1923                 /* might as well read a page, it is fast enough */
1924                 if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
1925                         rc = cifs_readpage_worker(file, page, &offset);
1926                 } else {
1927                 /* should we try using another file handle if there is one -
1928                    how would we lock it to prevent close of that handle
1929                    racing with this read?
1930                    In any case this will be written out by commit_write */
1931                 }
1932         }
1933
1934         /* BB should we pass any errors back?
1935            e.g. if we do not have read access to the file */
1936         return 0;
1937 }
1938
1939 struct address_space_operations cifs_addr_ops = {
1940         .readpage = cifs_readpage,
1941         .readpages = cifs_readpages,
1942         .writepage = cifs_writepage,
1943         .writepages = cifs_writepages,
1944         .prepare_write = cifs_prepare_write,
1945         .commit_write = cifs_commit_write,
1946         .set_page_dirty = __set_page_dirty_nobuffers,
1947         /* .sync_page = cifs_sync_page, */
1948         /* .direct_IO = */
1949 };