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  *              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/smp_lock.h>
  31 #include <linux/writeback.h>
  32 #include <linux/task_io_accounting_ops.h>
  33 #include <linux/delay.h>
  34 #include <asm/div64.h>
  35 #include "cifsfs.h"
  36 #include "cifspdu.h"
  37 #include "cifsglob.h"
  38 #include "cifsproto.h"
  39 #include "cifs_unicode.h"
  40 #include "cifs_debug.h"
  41 #include "cifs_fs_sb.h"
  42
  43 static inline struct cifsFileInfo *cifs_init_private(
  44         struct cifsFileInfo *private_data, struct inode *inode,
  45         struct file *file, __u16 netfid)
  46 {
  47         memset(private_data, 0, sizeof(struct cifsFileInfo));
  48         private_data->netfid = netfid;
  49         private_data->pid = current->tgid;
  50         init_MUTEX(&private_data->fh_sem);
  51         init_MUTEX(&private_data->lock_sem);
  52         INIT_LIST_HEAD(&private_data->llist);
  53         private_data->pfile = file; /* needed for writepage */
  54         private_data->pInode = inode;
  55         private_data->invalidHandle = FALSE;
  56         private_data->closePend = FALSE;
  57         /* we have to track num writers to the inode, since writepages
  58         does not tell us which handle the write is for so there can
  59         be a close (overlapping with write) of the filehandle that
  60         cifs_writepages chose to use */
  61         atomic_set(&private_data->wrtPending,0);
  62
  63         return private_data;
  64 }
  65
  66 static inline int cifs_convert_flags(unsigned int flags)
  67 {
  68         if ((flags & O_ACCMODE) == O_RDONLY)
  69                 return GENERIC_READ;
  70         else if ((flags & O_ACCMODE) == O_WRONLY)
  71                 return GENERIC_WRITE;
  72         else if ((flags & O_ACCMODE) == O_RDWR) {
  73                 /* GENERIC_ALL is too much permission to request
  74                    can cause unnecessary access denied on create */
  75                 /* return GENERIC_ALL; */
  76                 return (GENERIC_READ | GENERIC_WRITE);
  77         }
  78
  79         return 0x20197;
  80 }
  81
  82 static inline int cifs_get_disposition(unsigned int flags)
  83 {
  84         if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
  85                 return FILE_CREATE;
  86         else if ((flags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
  87                 return FILE_OVERWRITE_IF;
  88         else if ((flags & O_CREAT) == O_CREAT)
  89                 return FILE_OPEN_IF;
  90         else if ((flags & O_TRUNC) == O_TRUNC)
  91                 return FILE_OVERWRITE;
  92         else
  93                 return FILE_OPEN;
  94 }
  95
  96 /* all arguments to this function must be checked for validity in caller */
  97 static inline int cifs_open_inode_helper(struct inode *inode, struct file *file,
  98         struct cifsInodeInfo *pCifsInode, struct cifsFileInfo *pCifsFile,
  99         struct cifsTconInfo *pTcon, int *oplock, FILE_ALL_INFO *buf,
 100         char *full_path, int xid)
 101 {
 102         struct timespec temp;
 103         int rc;
 104
 105         /* want handles we can use to read with first
 106            in the list so we do not have to walk the
 107            list to search for one in prepare_write */
 108         if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
 109                 list_add_tail(&pCifsFile->flist,
 110                               &pCifsInode->openFileList);
 111         } else {
 112                 list_add(&pCifsFile->flist,
 113                          &pCifsInode->openFileList);
 114         }
 115         write_unlock(&GlobalSMBSeslock);
 116         if (pCifsInode->clientCanCacheRead) {
 117                 /* we have the inode open somewhere else
 118                    no need to discard cache data */
 119                 goto client_can_cache;
 120         }
 121
 122         /* BB need same check in cifs_create too? */
 123         /* if not oplocked, invalidate inode pages if mtime or file
 124            size changed */
 125         temp = cifs_NTtimeToUnix(le64_to_cpu(buf->LastWriteTime));
 126         if (timespec_equal(&file->f_path.dentry->d_inode->i_mtime, &temp) &&
 127                            (file->f_path.dentry->d_inode->i_size ==
 128                             (loff_t)le64_to_cpu(buf->EndOfFile))) {
 129                 cFYI(1, ("inode unchanged on server"));
 130         } else {
 131                 if (file->f_path.dentry->d_inode->i_mapping) {
 132                 /* BB no need to lock inode until after invalidate
 133                    since namei code should already have it locked? */
 134                         filemap_write_and_wait(file->f_path.dentry->d_inode->i_mapping);
 135                 }
 136                 cFYI(1, ("invalidating remote inode since open detected it "
 137                          "changed"));
 138                 invalidate_remote_inode(file->f_path.dentry->d_inode);
 139         }
 140
 141 client_can_cache:
 142         if (pTcon->ses->capabilities & CAP_UNIX)
 143                 rc = cifs_get_inode_info_unix(&file->f_path.dentry->d_inode,
 144                         full_path, inode->i_sb, xid);
 145         else
 146                 rc = cifs_get_inode_info(&file->f_path.dentry->d_inode,
 147                         full_path, buf, inode->i_sb, xid);
 148
 149         if ((*oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 150                 pCifsInode->clientCanCacheAll = TRUE;
 151                 pCifsInode->clientCanCacheRead = TRUE;
 152                 cFYI(1, ("Exclusive Oplock granted on inode %p",
 153                          file->f_path.dentry->d_inode));
 154         } else if ((*oplock & 0xF) == OPLOCK_READ)
 155                 pCifsInode->clientCanCacheRead = TRUE;
 156
 157         return rc;
 158 }
 159
 160 int cifs_open(struct inode *inode, struct file *file)
 161 {
 162         int rc = -EACCES;
 163         int xid, oplock;
 164         struct cifs_sb_info *cifs_sb;
 165         struct cifsTconInfo *pTcon;
 166         struct cifsFileInfo *pCifsFile;
 167         struct cifsInodeInfo *pCifsInode;
 168         struct list_head *tmp;
 169         char *full_path = NULL;
 170         int desiredAccess;
 171         int disposition;
 172         __u16 netfid;
 173         FILE_ALL_INFO *buf = NULL;
 174
 175         xid = GetXid();
 176
 177         cifs_sb = CIFS_SB(inode->i_sb);
 178         pTcon = cifs_sb->tcon;
 179
 180         if (file->f_flags & O_CREAT) {
 181                 /* search inode for this file and fill in file->private_data */
 182                 pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
 183                 read_lock(&GlobalSMBSeslock);
 184                 list_for_each(tmp, &pCifsInode->openFileList) {
 185                         pCifsFile = list_entry(tmp, struct cifsFileInfo,
 186                                                flist);
 187                         if ((pCifsFile->pfile == NULL) &&
 188                             (pCifsFile->pid == current->tgid)) {
 189                                 /* mode set in cifs_create */
 190
 191                                 /* needed for writepage */
 192                                 pCifsFile->pfile = file;
 193
 194                                 file->private_data = pCifsFile;
 195                                 break;
 196                         }
 197                 }
 198                 read_unlock(&GlobalSMBSeslock);
 199                 if (file->private_data != NULL) {
 200                         rc = 0;
 201                         FreeXid(xid);
 202                         return rc;
 203                 } else {
 204                         if (file->f_flags & O_EXCL)
 205                                 cERROR(1, ("could not find file instance for "
 206                                            "new file %p", file));
 207                 }
 208         }
 209
 210         full_path = build_path_from_dentry(file->f_path.dentry);
 211         if (full_path == NULL) {
 212                 FreeXid(xid);
 213                 return -ENOMEM;
 214         }
 215
 216         cFYI(1, (" inode = 0x%p file flags are 0x%x for %s",
 217                  inode, file->f_flags, full_path));
 218         desiredAccess = cifs_convert_flags(file->f_flags);
 219
 220 /*********************************************************************
 221  *  open flag mapping table:
 222  *
 223  *      POSIX Flag            CIFS Disposition
 224  *      ----------            ----------------
 225  *      O_CREAT               FILE_OPEN_IF
 226  *      O_CREAT | O_EXCL      FILE_CREATE
 227  *      O_CREAT | O_TRUNC     FILE_OVERWRITE_IF
 228  *      O_TRUNC               FILE_OVERWRITE
 229  *      none of the above     FILE_OPEN
 230  *
 231  *      Note that there is not a direct match between disposition
 232  *      FILE_SUPERSEDE (ie create whether or not file exists although
 233  *      O_CREAT | O_TRUNC is similar but truncates the existing
 234  *      file rather than creating a new file as FILE_SUPERSEDE does
 235  *      (which uses the attributes / metadata passed in on open call)
 236  *?
 237  *?  O_SYNC is a reasonable match to CIFS writethrough flag
 238  *?  and the read write flags match reasonably.  O_LARGEFILE
 239  *?  is irrelevant because largefile support is always used
 240  *?  by this client. Flags O_APPEND, O_DIRECT, O_DIRECTORY,
 241  *       O_FASYNC, O_NOFOLLOW, O_NONBLOCK need further investigation
 242  *********************************************************************/
 243
 244         disposition = cifs_get_disposition(file->f_flags);
 245
 246         if (oplockEnabled)
 247                 oplock = REQ_OPLOCK;
 248         else
 249                 oplock = FALSE;
 250
 251         /* BB pass O_SYNC flag through on file attributes .. BB */
 252
 253         /* Also refresh inode by passing in file_info buf returned by SMBOpen
 254            and calling get_inode_info with returned buf (at least helps
 255            non-Unix server case) */
 256
 257         /* BB we can not do this if this is the second open of a file
 258            and the first handle has writebehind data, we might be
 259            able to simply do a filemap_fdatawrite/filemap_fdatawait first */
 260         buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 261         if (!buf) {
 262                 rc = -ENOMEM;
 263                 goto out;
 264         }
 265
 266         if (cifs_sb->tcon->ses->capabilities & CAP_NT_SMBS)
 267                 rc = CIFSSMBOpen(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         else
 272                 rc = -EIO; /* no NT SMB support fall into legacy open below */
 273
 274         if (rc == -EIO) {
 275                 /* Old server, try legacy style OpenX */
 276                 rc = SMBLegacyOpen(xid, pTcon, full_path, disposition,
 277                         desiredAccess, CREATE_NOT_DIR, &netfid, &oplock, buf,
 278                         cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
 279                                 & CIFS_MOUNT_MAP_SPECIAL_CHR);
 280         }
 281         if (rc) {
 282                 cFYI(1, ("cifs_open returned 0x%x", rc));
 283                 goto out;
 284         }
 285         file->private_data =
 286                 kmalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 287         if (file->private_data == NULL) {
 288                 rc = -ENOMEM;
 289                 goto out;
 290         }
 291         pCifsFile = cifs_init_private(file->private_data, inode, file, netfid);
 292         write_lock(&GlobalSMBSeslock);
 293         list_add(&pCifsFile->tlist, &pTcon->openFileList);
 294
 295         pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
 296         if (pCifsInode) {
 297                 rc = cifs_open_inode_helper(inode, file, pCifsInode,
 298                                             pCifsFile, pTcon,
 299                                             &oplock, buf, full_path, xid);
 300         } else {
 301                 write_unlock(&GlobalSMBSeslock);
 302         }
 303
 304         if (oplock & CIFS_CREATE_ACTION) {
 305                 /* time to set mode which we can not set earlier due to
 306                    problems creating new read-only files */
 307                 if (cifs_sb->tcon->ses->capabilities & CAP_UNIX) {
 308                         CIFSSMBUnixSetPerms(xid, pTcon, full_path,
 309                                             inode->i_mode,
 310                                             (__u64)-1, (__u64)-1, 0 /* dev */,
 311                                             cifs_sb->local_nls,
 312                                             cifs_sb->mnt_cifs_flags &
 313                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 314                 } else {
 315                         /* BB implement via Windows security descriptors eg
 316                            CIFSSMBWinSetPerms(xid, pTcon, full_path, mode,
 317                                               -1, -1, local_nls);
 318                            in the meantime could set r/o dos attribute when
 319                            perms are eg: mode & 0222 == 0 */
 320                 }
 321         }
 322
 323 out:
 324         kfree(buf);
 325         kfree(full_path);
 326         FreeXid(xid);
 327         return rc;
 328 }
 329
 330 /* Try to reacquire byte range locks that were released when session */
 331 /* to server was lost */
 332 static int cifs_relock_file(struct cifsFileInfo *cifsFile)
 333 {
 334         int rc = 0;
 335
 336 /* BB list all locks open on this file and relock */
 337
 338         return rc;
 339 }
 340
 341 static int cifs_reopen_file(struct inode *inode, struct file *file,
 342         int can_flush)
 343 {
 344         int rc = -EACCES;
 345         int xid, oplock;
 346         struct cifs_sb_info *cifs_sb;
 347         struct cifsTconInfo *pTcon;
 348         struct cifsFileInfo *pCifsFile;
 349         struct cifsInodeInfo *pCifsInode;
 350         char *full_path = NULL;
 351         int desiredAccess;
 352         int disposition = FILE_OPEN;
 353         __u16 netfid;
 354
 355         if (inode == NULL)
 356                 return -EBADF;
 357         if (file->private_data) {
 358                 pCifsFile = (struct cifsFileInfo *)file->private_data;
 359         } else
 360                 return -EBADF;
 361
 362         xid = GetXid();
 363         down(&pCifsFile->fh_sem);
 364         if (pCifsFile->invalidHandle == FALSE) {
 365                 up(&pCifsFile->fh_sem);
 366                 FreeXid(xid);
 367                 return 0;
 368         }
 369
 370         if (file->f_path.dentry == NULL) {
 371                 up(&pCifsFile->fh_sem);
 372                 cFYI(1, ("failed file reopen, no valid name if dentry freed"));
 373                 FreeXid(xid);
 374                 return -EBADF;
 375         }
 376         cifs_sb = CIFS_SB(inode->i_sb);
 377         pTcon = cifs_sb->tcon;
 378 /* can not grab rename sem here because various ops, including
 379    those that already have the rename sem can end up causing writepage
 380    to get called and if the server was down that means we end up here,
 381    and we can never tell if the caller already has the rename_sem */
 382         full_path = build_path_from_dentry(file->f_path.dentry);
 383         if (full_path == NULL) {
 384                 up(&pCifsFile->fh_sem);
 385                 FreeXid(xid);
 386                 return -ENOMEM;
 387         }
 388
 389         cFYI(1, (" inode = 0x%p file flags are 0x%x for %s",
 390                  inode, file->f_flags,full_path));
 391         desiredAccess = cifs_convert_flags(file->f_flags);
 392
 393         if (oplockEnabled)
 394                 oplock = REQ_OPLOCK;
 395         else
 396                 oplock = FALSE;
 397
 398         /* Can not refresh inode by passing in file_info buf to be returned
 399            by SMBOpen and then calling get_inode_info with returned buf
 400            since file might have write behind data that needs to be flushed
 401            and server version of file size can be stale. If we knew for sure
 402            that inode was not dirty locally we could do this */
 403
 404 /*      buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 405         if (buf == 0) {
 406                 up(&pCifsFile->fh_sem);
 407                 kfree(full_path);
 408                 FreeXid(xid);
 409                 return -ENOMEM;
 410         } */
 411         rc = CIFSSMBOpen(xid, pTcon, full_path, disposition, desiredAccess,
 412                          CREATE_NOT_DIR, &netfid, &oplock, NULL,
 413                          cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
 414                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 415         if (rc) {
 416                 up(&pCifsFile->fh_sem);
 417                 cFYI(1, ("cifs_open returned 0x%x", rc));
 418                 cFYI(1, ("oplock: %d", oplock));
 419         } else {
 420                 pCifsFile->netfid = netfid;
 421                 pCifsFile->invalidHandle = FALSE;
 422                 up(&pCifsFile->fh_sem);
 423                 pCifsInode = CIFS_I(inode);
 424                 if (pCifsInode) {
 425                         if (can_flush) {
 426                                 filemap_write_and_wait(inode->i_mapping);
 427                         /* temporarily disable caching while we
 428                            go to server to get inode info */
 429                                 pCifsInode->clientCanCacheAll = FALSE;
 430                                 pCifsInode->clientCanCacheRead = FALSE;
 431                                 if (pTcon->ses->capabilities & CAP_UNIX)
 432                                         rc = cifs_get_inode_info_unix(&inode,
 433                                                 full_path, inode->i_sb, xid);
 434                                 else
 435                                         rc = cifs_get_inode_info(&inode,
 436                                                 full_path, NULL, inode->i_sb,
 437                                                 xid);
 438                         } /* else we are writing out data to server already
 439                              and could deadlock if we tried to flush data, and
 440                              since we do not know if we have data that would
 441                              invalidate the current end of file on the server
 442                              we can not go to the server to get the new inod
 443                              info */
 444                         if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 445                                 pCifsInode->clientCanCacheAll = TRUE;
 446                                 pCifsInode->clientCanCacheRead = TRUE;
 447                                 cFYI(1, ("Exclusive Oplock granted on inode %p",
 448                                          file->f_path.dentry->d_inode));
 449                         } else if ((oplock & 0xF) == OPLOCK_READ) {
 450                                 pCifsInode->clientCanCacheRead = TRUE;
 451                                 pCifsInode->clientCanCacheAll = FALSE;
 452                         } else {
 453                                 pCifsInode->clientCanCacheRead = FALSE;
 454                                 pCifsInode->clientCanCacheAll = FALSE;
 455                         }
 456                         cifs_relock_file(pCifsFile);
 457                 }
 458         }
 459
 460         kfree(full_path);
 461         FreeXid(xid);
 462         return rc;
 463 }
 464
 465 int cifs_close(struct inode *inode, struct file *file)
 466 {
 467         int rc = 0;
 468         int xid;
 469         struct cifs_sb_info *cifs_sb;
 470         struct cifsTconInfo *pTcon;
 471         struct cifsFileInfo *pSMBFile =
 472                 (struct cifsFileInfo *)file->private_data;
 473
 474         xid = GetXid();
 475
 476         cifs_sb = CIFS_SB(inode->i_sb);
 477         pTcon = cifs_sb->tcon;
 478         if (pSMBFile) {
 479                 struct cifsLockInfo *li, *tmp;
 480
 481                 pSMBFile->closePend = TRUE;
 482                 if (pTcon) {
 483                         /* no sense reconnecting to close a file that is
 484                            already closed */
 485                         if (pTcon->tidStatus != CifsNeedReconnect) {
 486                                 int timeout = 2;
 487                                 while((atomic_read(&pSMBFile->wrtPending) != 0)
 488                                          && (timeout < 1000) ) {
 489                                         /* Give write a better chance to get to
 490                                         server ahead of the close.  We do not
 491                                         want to add a wait_q here as it would
 492                                         increase the memory utilization as
 493                                         the struct would be in each open file,
 494                                         but this should give enough time to
 495                                         clear the socket */
 496 #ifdef CONFIG_CIFS_DEBUG2
 497                                         cFYI(1,("close delay, write pending"));
 498 #endif /* DEBUG2 */
 499                                         msleep(timeout);
 500                                         timeout *= 4;
 501                                 }
 502                                 if(atomic_read(&pSMBFile->wrtPending))
 503                                         cERROR(1,("close with pending writes"));
 504                                 rc = CIFSSMBClose(xid, pTcon,
 505                                                   pSMBFile->netfid);
 506                         }
 507                 }
 508
 509                 /* Delete any outstanding lock records.
 510                    We'll lose them when the file is closed anyway. */
 511                 down(&pSMBFile->lock_sem);
 512                 list_for_each_entry_safe(li, tmp, &pSMBFile->llist, llist) {
 513                         list_del(&li->llist);
 514                         kfree(li);
 515                 }
 516                 up(&pSMBFile->lock_sem);
 517
 518                 write_lock(&GlobalSMBSeslock);
 519                 list_del(&pSMBFile->flist);
 520                 list_del(&pSMBFile->tlist);
 521                 write_unlock(&GlobalSMBSeslock);
 522                 kfree(pSMBFile->search_resume_name);
 523                 kfree(file->private_data);
 524                 file->private_data = NULL;
 525         } else
 526                 rc = -EBADF;
 527
 528         if (list_empty(&(CIFS_I(inode)->openFileList))) {
 529                 cFYI(1, ("closing last open instance for inode %p", inode));
 530                 /* if the file is not open we do not know if we can cache info
 531                    on this inode, much less write behind and read ahead */
 532                 CIFS_I(inode)->clientCanCacheRead = FALSE;
 533                 CIFS_I(inode)->clientCanCacheAll  = FALSE;
 534         }
 535         if ((rc ==0) && CIFS_I(inode)->write_behind_rc)
 536                 rc = CIFS_I(inode)->write_behind_rc;
 537         FreeXid(xid);
 538         return rc;
 539 }
 540
 541 int cifs_closedir(struct inode *inode, struct file *file)
 542 {
 543         int rc = 0;
 544         int xid;
 545         struct cifsFileInfo *pCFileStruct =
 546             (struct cifsFileInfo *)file->private_data;
 547         char *ptmp;
 548
 549         cFYI(1, ("Closedir inode = 0x%p", inode));
 550
 551         xid = GetXid();
 552
 553         if (pCFileStruct) {
 554                 struct cifsTconInfo *pTcon;
 555                 struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 556
 557                 pTcon = cifs_sb->tcon;
 558
 559                 cFYI(1, ("Freeing private data in close dir"));
 560                 if ((pCFileStruct->srch_inf.endOfSearch == FALSE) &&
 561                    (pCFileStruct->invalidHandle == FALSE)) {
 562                         pCFileStruct->invalidHandle = TRUE;
 563                         rc = CIFSFindClose(xid, pTcon, pCFileStruct->netfid);
 564                         cFYI(1, ("Closing uncompleted readdir with rc %d",
 565                                  rc));
 566                         /* not much we can do if it fails anyway, ignore rc */
 567                         rc = 0;
 568                 }
 569                 ptmp = pCFileStruct->srch_inf.ntwrk_buf_start;
 570                 if (ptmp) {
 571                         cFYI(1, ("closedir free smb buf in srch struct"));
 572                         pCFileStruct->srch_inf.ntwrk_buf_start = NULL;
 573                         if(pCFileStruct->srch_inf.smallBuf)
 574                                 cifs_small_buf_release(ptmp);
 575                         else
 576                                 cifs_buf_release(ptmp);
 577                 }
 578                 ptmp = pCFileStruct->search_resume_name;
 579                 if (ptmp) {
 580                         cFYI(1, ("closedir free resume name"));
 581                         pCFileStruct->search_resume_name = NULL;
 582                         kfree(ptmp);
 583                 }
 584                 kfree(file->private_data);
 585                 file->private_data = NULL;
 586         }
 587         /* BB can we lock the filestruct while this is going on? */
 588         FreeXid(xid);
 589         return rc;
 590 }
 591
 592 static int store_file_lock(struct cifsFileInfo *fid, __u64 len,
 593                                 __u64 offset, __u8 lockType)
 594 {
 595         struct cifsLockInfo *li = kmalloc(sizeof(struct cifsLockInfo), GFP_KERNEL);
 596         if (li == NULL)
 597                 return -ENOMEM;
 598         li->offset = offset;
 599         li->length = len;
 600         li->type = lockType;
 601         down(&fid->lock_sem);
 602         list_add(&li->llist, &fid->llist);
 603         up(&fid->lock_sem);
 604         return 0;
 605 }
 606
 607 int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
 608 {
 609         int rc, xid;
 610         __u32 numLock = 0;
 611         __u32 numUnlock = 0;
 612         __u64 length;
 613         int wait_flag = FALSE;
 614         struct cifs_sb_info *cifs_sb;
 615         struct cifsTconInfo *pTcon;
 616         __u16 netfid;
 617         __u8 lockType = LOCKING_ANDX_LARGE_FILES;
 618         int posix_locking;
 619
 620         length = 1 + pfLock->fl_end - pfLock->fl_start;
 621         rc = -EACCES;
 622         xid = GetXid();
 623
 624         cFYI(1, ("Lock parm: 0x%x flockflags: "
 625                  "0x%x flocktype: 0x%x start: %lld end: %lld",
 626                 cmd, pfLock->fl_flags, pfLock->fl_type, pfLock->fl_start,
 627                 pfLock->fl_end));
 628
 629         if (pfLock->fl_flags & FL_POSIX)
 630                 cFYI(1, ("Posix"));
 631         if (pfLock->fl_flags & FL_FLOCK)
 632                 cFYI(1, ("Flock"));
 633         if (pfLock->fl_flags & FL_SLEEP) {
 634                 cFYI(1, ("Blocking lock"));
 635                 wait_flag = TRUE;
 636         }
 637         if (pfLock->fl_flags & FL_ACCESS)
 638                 cFYI(1, ("Process suspended by mandatory locking - "
 639                          "not implemented yet"));
 640         if (pfLock->fl_flags & FL_LEASE)
 641                 cFYI(1, ("Lease on file - not implemented yet"));
 642         if (pfLock->fl_flags &
 643             (~(FL_POSIX | FL_FLOCK | FL_SLEEP | FL_ACCESS | FL_LEASE)))
 644                 cFYI(1, ("Unknown lock flags 0x%x", pfLock->fl_flags));
 645
 646         if (pfLock->fl_type == F_WRLCK) {
 647                 cFYI(1, ("F_WRLCK "));
 648                 numLock = 1;
 649         } else if (pfLock->fl_type == F_UNLCK) {
 650                 cFYI(1, ("F_UNLCK"));
 651                 numUnlock = 1;
 652                 /* Check if unlock includes more than
 653                 one lock range */
 654         } else if (pfLock->fl_type == F_RDLCK) {
 655                 cFYI(1, ("F_RDLCK"));
 656                 lockType |= LOCKING_ANDX_SHARED_LOCK;
 657                 numLock = 1;
 658         } else if (pfLock->fl_type == F_EXLCK) {
 659                 cFYI(1, ("F_EXLCK"));
 660                 numLock = 1;
 661         } else if (pfLock->fl_type == F_SHLCK) {
 662                 cFYI(1, ("F_SHLCK"));
 663                 lockType |= LOCKING_ANDX_SHARED_LOCK;
 664                 numLock = 1;
 665         } else
 666                 cFYI(1, ("Unknown type of lock"));
 667
 668         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 669         pTcon = cifs_sb->tcon;
 670
 671         if (file->private_data == NULL) {
 672                 FreeXid(xid);
 673                 return -EBADF;
 674         }
 675         netfid = ((struct cifsFileInfo *)file->private_data)->netfid;
 676
 677         posix_locking = (cifs_sb->tcon->ses->capabilities & CAP_UNIX) &&
 678                         (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(cifs_sb->tcon->fsUnixInfo.Capability));
 679
 680         /* BB add code here to normalize offset and length to
 681         account for negative length which we can not accept over the
 682         wire */
 683         if (IS_GETLK(cmd)) {
 684                 if(posix_locking) {
 685                         int posix_lock_type;
 686                         if(lockType & LOCKING_ANDX_SHARED_LOCK)
 687                                 posix_lock_type = CIFS_RDLCK;
 688                         else
 689                                 posix_lock_type = CIFS_WRLCK;
 690                         rc = CIFSSMBPosixLock(xid, pTcon, netfid, 1 /* get */,
 691                                         length, pfLock,
 692                                         posix_lock_type, wait_flag);
 693                         FreeXid(xid);
 694                         return rc;
 695                 }
 696
 697                 /* BB we could chain these into one lock request BB */
 698                 rc = CIFSSMBLock(xid, pTcon, netfid, length, pfLock->fl_start,
 699                                  0, 1, lockType, 0 /* wait flag */ );
 700                 if (rc == 0) {
 701                         rc = CIFSSMBLock(xid, pTcon, netfid, length,
 702                                          pfLock->fl_start, 1 /* numUnlock */ ,
 703                                          0 /* numLock */ , lockType,
 704                                          0 /* wait flag */ );
 705                         pfLock->fl_type = F_UNLCK;
 706                         if (rc != 0)
 707                                 cERROR(1, ("Error unlocking previously locked "
 708                                            "range %d during test of lock", rc));
 709                         rc = 0;
 710
 711                 } else {
 712                         /* if rc == ERR_SHARING_VIOLATION ? */
 713                         rc = 0; /* do not change lock type to unlock
 714                                    since range in use */
 715                 }
 716
 717                 FreeXid(xid);
 718                 return rc;
 719         }
 720
 721         if (!numLock && !numUnlock) {
 722                 /* if no lock or unlock then nothing
 723                 to do since we do not know what it is */
 724                 FreeXid(xid);
 725                 return -EOPNOTSUPP;
 726         }
 727
 728         if (posix_locking) {
 729                 int posix_lock_type;
 730                 if(lockType & LOCKING_ANDX_SHARED_LOCK)
 731                         posix_lock_type = CIFS_RDLCK;
 732                 else
 733                         posix_lock_type = CIFS_WRLCK;
 734
 735                 if(numUnlock == 1)
 736                         posix_lock_type = CIFS_UNLCK;
 737
 738                 rc = CIFSSMBPosixLock(xid, pTcon, netfid, 0 /* set */,
 739                                       length, pfLock,
 740                                       posix_lock_type, wait_flag);
 741         } else {
 742                 struct cifsFileInfo *fid = (struct cifsFileInfo *)file->private_data;
 743
 744                 if (numLock) {
 745                         rc = CIFSSMBLock(xid, pTcon, netfid, length, pfLock->fl_start,
 746                                         0, numLock, lockType, wait_flag);
 747
 748                         if (rc == 0) {
 749                                 /* For Windows locks we must store them. */
 750                                 rc = store_file_lock(fid, length,
 751                                                 pfLock->fl_start, lockType);
 752                         }
 753                 } else if (numUnlock) {
 754                         /* For each stored lock that this unlock overlaps
 755                            completely, unlock it. */
 756                         int stored_rc = 0;
 757                         struct cifsLockInfo *li, *tmp;
 758
 759                         rc = 0;
 760                         down(&fid->lock_sem);
 761                         list_for_each_entry_safe(li, tmp, &fid->llist, llist) {
 762                                 if (pfLock->fl_start <= li->offset &&
 763                                                 length >= li->length) {
 764                                         stored_rc = CIFSSMBLock(xid, pTcon, netfid,
 765                                                         li->length, li->offset,
 766                                                         1, 0, li->type, FALSE);
 767                                         if (stored_rc)
 768                                                 rc = stored_rc;
 769
 770                                         list_del(&li->llist);
 771                                         kfree(li);
 772                                 }
 773                         }
 774                         up(&fid->lock_sem);
 775                 }
 776         }
 777
 778         if (pfLock->fl_flags & FL_POSIX)
 779                 posix_lock_file_wait(file, pfLock);
 780         FreeXid(xid);
 781         return rc;
 782 }
 783
 784 ssize_t cifs_user_write(struct file *file, const char __user *write_data,
 785         size_t write_size, loff_t *poffset)
 786 {
 787         int rc = 0;
 788         unsigned int bytes_written = 0;
 789         unsigned int total_written;
 790         struct cifs_sb_info *cifs_sb;
 791         struct cifsTconInfo *pTcon;
 792         int xid, long_op;
 793         struct cifsFileInfo *open_file;
 794
 795         if (file->f_path.dentry == NULL)
 796                 return -EBADF;
 797
 798         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 799         if (cifs_sb == NULL)
 800                 return -EBADF;
 801
 802         pTcon = cifs_sb->tcon;
 803
 804         /* cFYI(1,
 805            (" write %d bytes to offset %lld of %s", write_size,
 806            *poffset, file->f_path.dentry->d_name.name)); */
 807
 808         if (file->private_data == NULL)
 809                 return -EBADF;
 810         else
 811                 open_file = (struct cifsFileInfo *) file->private_data;
 812
 813         xid = GetXid();
 814         if (file->f_path.dentry->d_inode == NULL) {
 815                 FreeXid(xid);
 816                 return -EBADF;
 817         }
 818
 819         if (*poffset > file->f_path.dentry->d_inode->i_size)
 820                 long_op = 2; /* writes past end of file can take a long time */
 821         else
 822                 long_op = 1;
 823
 824         for (total_written = 0; write_size > total_written;
 825              total_written += bytes_written) {
 826                 rc = -EAGAIN;
 827                 while (rc == -EAGAIN) {
 828                         if (file->private_data == NULL) {
 829                                 /* file has been closed on us */
 830                                 FreeXid(xid);
 831                         /* if we have gotten here we have written some data
 832                            and blocked, and the file has been freed on us while
 833                            we blocked so return what we managed to write */
 834                                 return total_written;
 835                         }
 836                         if (open_file->closePend) {
 837                                 FreeXid(xid);
 838                                 if (total_written)
 839                                         return total_written;
 840                                 else
 841                                         return -EBADF;
 842                         }
 843                         if (open_file->invalidHandle) {
 844                                 if ((file->f_path.dentry == NULL) ||
 845                                     (file->f_path.dentry->d_inode == NULL)) {
 846                                         FreeXid(xid);
 847                                         return total_written;
 848                                 }
 849                                 /* we could deadlock if we called
 850                                    filemap_fdatawait from here so tell
 851                                    reopen_file not to flush data to server
 852                                    now */
 853                                 rc = cifs_reopen_file(file->f_path.dentry->d_inode,
 854                                         file, FALSE);
 855                                 if (rc != 0)
 856                                         break;
 857                         }
 858
 859                         rc = CIFSSMBWrite(xid, pTcon,
 860                                 open_file->netfid,
 861                                 min_t(const int, cifs_sb->wsize,
 862                                       write_size - total_written),
 863                                 *poffset, &bytes_written,
 864                                 NULL, write_data + total_written, long_op);
 865                 }
 866                 if (rc || (bytes_written == 0)) {
 867                         if (total_written)
 868                                 break;
 869                         else {
 870                                 FreeXid(xid);
 871                                 return rc;
 872                         }
 873                 } else
 874                         *poffset += bytes_written;
 875                 long_op = FALSE; /* subsequent writes fast -
 876                                     15 seconds is plenty */
 877         }
 878
 879         cifs_stats_bytes_written(pTcon, total_written);
 880
 881         /* since the write may have blocked check these pointers again */
 882         if (file->f_path.dentry) {
 883                 if (file->f_path.dentry->d_inode) {
 884                         struct inode *inode = file->f_path.dentry->d_inode;
 885                         inode->i_ctime = inode->i_mtime =
 886                                 current_fs_time(inode->i_sb);
 887                         if (total_written > 0) {
 888                                 if (*poffset > file->f_path.dentry->d_inode->i_size)
 889                                         i_size_write(file->f_path.dentry->d_inode,
 890                                         *poffset);
 891                         }
 892                         mark_inode_dirty_sync(file->f_path.dentry->d_inode);
 893                 }
 894         }
 895         FreeXid(xid);
 896         return total_written;
 897 }
 898
 899 static ssize_t cifs_write(struct file *file, const char *write_data,
 900         size_t write_size, loff_t *poffset)
 901 {
 902         int rc = 0;
 903         unsigned int bytes_written = 0;
 904         unsigned int total_written;
 905         struct cifs_sb_info *cifs_sb;
 906         struct cifsTconInfo *pTcon;
 907         int xid, long_op;
 908         struct cifsFileInfo *open_file;
 909
 910         if (file->f_path.dentry == NULL)
 911                 return -EBADF;
 912
 913         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 914         if (cifs_sb == NULL)
 915                 return -EBADF;
 916
 917         pTcon = cifs_sb->tcon;
 918
 919         cFYI(1,("write %zd bytes to offset %lld of %s", write_size,
 920            *poffset, file->f_path.dentry->d_name.name));
 921
 922         if (file->private_data == NULL)
 923                 return -EBADF;
 924         else
 925                 open_file = (struct cifsFileInfo *)file->private_data;
 926
 927         xid = GetXid();
 928         if (file->f_path.dentry->d_inode == NULL) {
 929                 FreeXid(xid);
 930                 return -EBADF;
 931         }
 932
 933         if (*poffset > file->f_path.dentry->d_inode->i_size)
 934                 long_op = 2; /* writes past end of file can take a long time */
 935         else
 936                 long_op = 1;
 937
 938         for (total_written = 0; write_size > total_written;
 939              total_written += bytes_written) {
 940                 rc = -EAGAIN;
 941                 while (rc == -EAGAIN) {
 942                         if (file->private_data == NULL) {
 943                                 /* file has been closed on us */
 944                                 FreeXid(xid);
 945                         /* if we have gotten here we have written some data
 946                            and blocked, and the file has been freed on us
 947                            while we blocked so return what we managed to
 948                            write */
 949                                 return total_written;
 950                         }
 951                         if (open_file->closePend) {
 952                                 FreeXid(xid);
 953                                 if (total_written)
 954                                         return total_written;
 955                                 else
 956                                         return -EBADF;
 957                         }
 958                         if (open_file->invalidHandle) {
 959                                 if ((file->f_path.dentry == NULL) ||
 960                                    (file->f_path.dentry->d_inode == NULL)) {
 961                                         FreeXid(xid);
 962                                         return total_written;
 963                                 }
 964                                 /* we could deadlock if we called
 965                                    filemap_fdatawait from here so tell
 966                                    reopen_file not to flush data to
 967                                    server now */
 968                                 rc = cifs_reopen_file(file->f_path.dentry->d_inode,
 969                                         file, FALSE);
 970                                 if (rc != 0)
 971                                         break;
 972                         }
 973                         if(experimEnabled || (pTcon->ses->server &&
 974                                 ((pTcon->ses->server->secMode &
 975                                 (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
 976                                 == 0))) {
 977                                 struct kvec iov[2];
 978                                 unsigned int len;
 979
 980                                 len = min((size_t)cifs_sb->wsize,
 981                                           write_size - total_written);
 982                                 /* iov[0] is reserved for smb header */
 983                                 iov[1].iov_base = (char *)write_data +
 984                                                   total_written;
 985                                 iov[1].iov_len = len;
 986                                 rc = CIFSSMBWrite2(xid, pTcon,
 987                                                 open_file->netfid, len,
 988                                                 *poffset, &bytes_written,
 989                                                 iov, 1, long_op);
 990                         } else
 991                                 rc = CIFSSMBWrite(xid, pTcon,
 992                                          open_file->netfid,
 993                                          min_t(const int, cifs_sb->wsize,
 994                                                write_size - total_written),
 995                                          *poffset, &bytes_written,
 996                                          write_data + total_written,
 997                                          NULL, long_op);
 998                 }
 999                 if (rc || (bytes_written == 0)) {
1000                         if (total_written)
1001                                 break;
1002                         else {
1003                                 FreeXid(xid);
1004                                 return rc;
1005                         }
1006                 } else
1007                         *poffset += bytes_written;
1008                 long_op = FALSE; /* subsequent writes fast -
1009                                     15 seconds is plenty */
1010         }
1011
1012         cifs_stats_bytes_written(pTcon, total_written);
1013
1014         /* since the write may have blocked check these pointers again */
1015         if (file->f_path.dentry) {
1016                 if (file->f_path.dentry->d_inode) {
1017                         file->f_path.dentry->d_inode->i_ctime =
1018                         file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;
1019                         if (total_written > 0) {
1020                                 if (*poffset > file->f_path.dentry->d_inode->i_size)
1021                                         i_size_write(file->f_path.dentry->d_inode,
1022                                                      *poffset);
1023                         }
1024                         mark_inode_dirty_sync(file->f_path.dentry->d_inode);
1025                 }
1026         }
1027         FreeXid(xid);
1028         return total_written;
1029 }
1030
1031 struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode)
1032 {
1033         struct cifsFileInfo *open_file;
1034         int rc;
1035
1036         /* Having a null inode here (because mapping->host was set to zero by
1037         the VFS or MM) should not happen but we had reports of on oops (due to
1038         it being zero) during stress testcases so we need to check for it */
1039
1040         if(cifs_inode == NULL) {
1041                 cERROR(1,("Null inode passed to cifs_writeable_file"));
1042                 dump_stack();
1043                 return NULL;
1044         }
1045
1046         read_lock(&GlobalSMBSeslock);
1047         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
1048                 if (open_file->closePend)
1049                         continue;
1050                 if (open_file->pfile &&
1051                     ((open_file->pfile->f_flags & O_RDWR) ||
1052                      (open_file->pfile->f_flags & O_WRONLY))) {
1053                         atomic_inc(&open_file->wrtPending);
1054                         read_unlock(&GlobalSMBSeslock);
1055                         if((open_file->invalidHandle) &&
1056                            (!open_file->closePend) /* BB fixme -since the second clause can not be true remove it BB */) {
1057                                 rc = cifs_reopen_file(&cifs_inode->vfs_inode,
1058                                                       open_file->pfile, FALSE);
1059                                 /* if it fails, try another handle - might be */
1060                                 /* dangerous to hold up writepages with retry */
1061                                 if(rc) {
1062                                         cFYI(1,("failed on reopen file in wp"));
1063                                         read_lock(&GlobalSMBSeslock);
1064                                         /* can not use this handle, no write
1065                                         pending on this one after all */
1066                                         atomic_dec
1067                                              (&open_file->wrtPending);
1068                                         continue;
1069                                 }
1070                         }
1071                         return open_file;
1072                 }
1073         }
1074         read_unlock(&GlobalSMBSeslock);
1075         return NULL;
1076 }
1077
1078 static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
1079 {
1080         struct address_space *mapping = page->mapping;
1081         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1082         char *write_data;
1083         int rc = -EFAULT;
1084         int bytes_written = 0;
1085         struct cifs_sb_info *cifs_sb;
1086         struct cifsTconInfo *pTcon;
1087         struct inode *inode;
1088         struct cifsFileInfo *open_file;
1089
1090         if (!mapping || !mapping->host)
1091                 return -EFAULT;
1092
1093         inode = page->mapping->host;
1094         cifs_sb = CIFS_SB(inode->i_sb);
1095         pTcon = cifs_sb->tcon;
1096
1097         offset += (loff_t)from;
1098         write_data = kmap(page);
1099         write_data += from;
1100
1101         if ((to > PAGE_CACHE_SIZE) || (from > to)) {
1102                 kunmap(page);
1103                 return -EIO;
1104         }
1105
1106         /* racing with truncate? */
1107         if (offset > mapping->host->i_size) {
1108                 kunmap(page);
1109                 return 0; /* don't care */
1110         }
1111
1112         /* check to make sure that we are not extending the file */
1113         if (mapping->host->i_size - offset < (loff_t)to)
1114                 to = (unsigned)(mapping->host->i_size - offset);
1115
1116         open_file = find_writable_file(CIFS_I(mapping->host));
1117         if (open_file) {
1118                 bytes_written = cifs_write(open_file->pfile, write_data,
1119                                            to-from, &offset);
1120                 atomic_dec(&open_file->wrtPending);
1121                 /* Does mm or vfs already set times? */
1122                 inode->i_atime = inode->i_mtime = current_fs_time(inode->i_sb);
1123                 if ((bytes_written > 0) && (offset)) {
1124                         rc = 0;
1125                 } else if (bytes_written < 0) {
1126                         if (rc != -EBADF)
1127                                 rc = bytes_written;
1128                 }
1129         } else {
1130                 cFYI(1, ("No writeable filehandles for inode"));
1131                 rc = -EIO;
1132         }
1133
1134         kunmap(page);
1135         return rc;
1136 }
1137
1138 static int cifs_writepages(struct address_space *mapping,
1139                            struct writeback_control *wbc)
1140 {
1141         struct backing_dev_info *bdi = mapping->backing_dev_info;
1142         unsigned int bytes_to_write;
1143         unsigned int bytes_written;
1144         struct cifs_sb_info *cifs_sb;
1145         int done = 0;
1146         pgoff_t end;
1147         pgoff_t index;
1148         int range_whole = 0;
1149         struct kvec iov[32];
1150         int len;
1151         int n_iov = 0;
1152         pgoff_t next;
1153         int nr_pages;
1154         __u64 offset = 0;
1155         struct cifsFileInfo *open_file;
1156         struct page *page;
1157         struct pagevec pvec;
1158         int rc = 0;
1159         int scanned = 0;
1160         int xid;
1161
1162         cifs_sb = CIFS_SB(mapping->host->i_sb);
1163
1164         /*
1165          * If wsize is smaller that the page cache size, default to writing
1166          * one page at a time via cifs_writepage
1167          */
1168         if (cifs_sb->wsize < PAGE_CACHE_SIZE)
1169                 return generic_writepages(mapping, wbc);
1170
1171         if((cifs_sb->tcon->ses) && (cifs_sb->tcon->ses->server))
1172                 if(cifs_sb->tcon->ses->server->secMode &
1173                           (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
1174                         if(!experimEnabled)
1175                                 return generic_writepages(mapping, wbc);
1176
1177         /*
1178          * BB: Is this meaningful for a non-block-device file system?
1179          * If it is, we should test it again after we do I/O
1180          */
1181         if (wbc->nonblocking && bdi_write_congested(bdi)) {
1182                 wbc->encountered_congestion = 1;
1183                 return 0;
1184         }
1185
1186         xid = GetXid();
1187
1188         pagevec_init(&pvec, 0);
1189         if (wbc->range_cyclic) {
1190                 index = mapping->writeback_index; /* Start from prev offset */
1191                 end = -1;
1192         } else {
1193                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
1194                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
1195                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
1196                         range_whole = 1;
1197                 scanned = 1;
1198         }
1199 retry:
1200         while (!done && (index <= end) &&
1201                (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
1202                         PAGECACHE_TAG_DIRTY,
1203                         min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1))) {
1204                 int first;
1205                 unsigned int i;
1206
1207                 first = -1;
1208                 next = 0;
1209                 n_iov = 0;
1210                 bytes_to_write = 0;
1211
1212                 for (i = 0; i < nr_pages; i++) {
1213                         page = pvec.pages[i];
1214                         /*
1215                          * At this point we hold neither mapping->tree_lock nor
1216                          * lock on the page itself: the page may be truncated or
1217                          * invalidated (changing page->mapping to NULL), or even
1218                          * swizzled back from swapper_space to tmpfs file
1219                          * mapping
1220                          */
1221
1222                         if (first < 0)
1223                                 lock_page(page);
1224                         else if (TestSetPageLocked(page))
1225                                 break;
1226
1227                         if (unlikely(page->mapping != mapping)) {
1228                                 unlock_page(page);
1229                                 break;
1230                         }
1231
1232                         if (!wbc->range_cyclic && page->index > end) {
1233                                 done = 1;
1234                                 unlock_page(page);
1235                                 break;
1236                         }
1237
1238                         if (next && (page->index != next)) {
1239                                 /* Not next consecutive page */
1240                                 unlock_page(page);
1241                                 break;
1242                         }
1243
1244                         if (wbc->sync_mode != WB_SYNC_NONE)
1245                                 wait_on_page_writeback(page);
1246
1247                         if (PageWriteback(page) ||
1248                                         !test_clear_page_dirty(page)) {
1249                                 unlock_page(page);
1250                                 break;
1251                         }
1252
1253                         if (page_offset(page) >= mapping->host->i_size) {
1254                                 done = 1;
1255                                 unlock_page(page);
1256                                 break;
1257                         }
1258
1259                         /*
1260                          * BB can we get rid of this?  pages are held by pvec
1261                          */
1262                         page_cache_get(page);
1263
1264                         len = min(mapping->host->i_size - page_offset(page),
1265                                   (loff_t)PAGE_CACHE_SIZE);
1266
1267                         /* reserve iov[0] for the smb header */
1268                         n_iov++;
1269                         iov[n_iov].iov_base = kmap(page);
1270                         iov[n_iov].iov_len = len;
1271                         bytes_to_write += len;
1272
1273                         if (first < 0) {
1274                                 first = i;
1275                                 offset = page_offset(page);
1276                         }
1277                         next = page->index + 1;
1278                         if (bytes_to_write + PAGE_CACHE_SIZE > cifs_sb->wsize)
1279                                 break;
1280                 }
1281                 if (n_iov) {
1282                         /* Search for a writable handle every time we call
1283                          * CIFSSMBWrite2.  We can't rely on the last handle
1284                          * we used to still be valid
1285                          */
1286                         open_file = find_writable_file(CIFS_I(mapping->host));
1287                         if (!open_file) {
1288                                 cERROR(1, ("No writable handles for inode"));
1289                                 rc = -EBADF;
1290                         } else {
1291                                 rc = CIFSSMBWrite2(xid, cifs_sb->tcon,
1292                                                    open_file->netfid,
1293                                                    bytes_to_write, offset,
1294                                                    &bytes_written, iov, n_iov,
1295                                                    1);
1296                                 atomic_dec(&open_file->wrtPending);
1297                                 if (rc || bytes_written < bytes_to_write) {
1298                                         cERROR(1,("Write2 ret %d, written = %d",
1299                                                   rc, bytes_written));
1300                                         /* BB what if continued retry is
1301                                            requested via mount flags? */
1302                                         set_bit(AS_EIO, &mapping->flags);
1303                                 } else {
1304                                         cifs_stats_bytes_written(cifs_sb->tcon,
1305                                                                  bytes_written);
1306                                 }
1307                         }
1308                         for (i = 0; i < n_iov; i++) {
1309                                 page = pvec.pages[first + i];
1310                                 /* Should we also set page error on
1311                                 success rc but too little data written? */
1312                                 /* BB investigate retry logic on temporary
1313                                 server crash cases and how recovery works
1314                                 when page marked as error */
1315                                 if(rc)
1316                                         SetPageError(page);
1317                                 kunmap(page);
1318                                 unlock_page(page);
1319                                 page_cache_release(page);
1320                         }
1321                         if ((wbc->nr_to_write -= n_iov) <= 0)
1322                                 done = 1;
1323                         index = next;
1324                 }
1325                 pagevec_release(&pvec);
1326         }
1327         if (!scanned && !done) {
1328                 /*
1329                  * We hit the last page and there is more work to be done: wrap
1330                  * back to the start of the file
1331                  */
1332                 scanned = 1;
1333                 index = 0;
1334                 goto retry;
1335         }
1336         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
1337                 mapping->writeback_index = index;
1338
1339         FreeXid(xid);
1340
1341         return rc;
1342 }
1343
1344 static int cifs_writepage(struct page* page, struct writeback_control *wbc)
1345 {
1346         int rc = -EFAULT;
1347         int xid;
1348
1349         xid = GetXid();
1350 /* BB add check for wbc flags */
1351         page_cache_get(page);
1352         if (!PageUptodate(page)) {
1353                 cFYI(1, ("ppw - page not up to date"));
1354         }
1355
1356         rc = cifs_partialpagewrite(page, 0, PAGE_CACHE_SIZE);
1357         SetPageUptodate(page); /* BB add check for error and Clearuptodate? */
1358         unlock_page(page);
1359         page_cache_release(page);
1360         FreeXid(xid);
1361         return rc;
1362 }
1363
1364 static int cifs_commit_write(struct file *file, struct page *page,
1365         unsigned offset, unsigned to)
1366 {
1367         int xid;
1368         int rc = 0;
1369         struct inode *inode = page->mapping->host;
1370         loff_t position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
1371         char *page_data;
1372
1373         xid = GetXid();
1374         cFYI(1, ("commit write for page %p up to position %lld for %d",
1375                  page, position, to));
1376         if (position > inode->i_size) {
1377                 i_size_write(inode, position);
1378                 /* if (file->private_data == NULL) {
1379                         rc = -EBADF;
1380                 } else {
1381                         open_file = (struct cifsFileInfo *)file->private_data;
1382                         cifs_sb = CIFS_SB(inode->i_sb);
1383                         rc = -EAGAIN;
1384                         while (rc == -EAGAIN) {
1385                                 if ((open_file->invalidHandle) &&
1386                                     (!open_file->closePend)) {
1387                                         rc = cifs_reopen_file(
1388                                                 file->f_path.dentry->d_inode, file);
1389                                         if (rc != 0)
1390                                                 break;
1391                                 }
1392                                 if (!open_file->closePend) {
1393                                         rc = CIFSSMBSetFileSize(xid,
1394                                                 cifs_sb->tcon, position,
1395                                                 open_file->netfid,
1396                                                 open_file->pid, FALSE);
1397                                 } else {
1398                                         rc = -EBADF;
1399                                         break;
1400                                 }
1401                         }
1402                         cFYI(1, (" SetEOF (commit write) rc = %d", rc));
1403                 } */
1404         }
1405         if (!PageUptodate(page)) {
1406                 position =  ((loff_t)page->index << PAGE_CACHE_SHIFT) + offset;
1407                 /* can not rely on (or let) writepage write this data */
1408                 if (to < offset) {
1409                         cFYI(1, ("Illegal offsets, can not copy from %d to %d",
1410                                 offset, to));
1411                         FreeXid(xid);
1412                         return rc;
1413                 }
1414                 /* this is probably better than directly calling
1415                    partialpage_write since in this function the file handle is
1416                    known which we might as well leverage */
1417                 /* BB check if anything else missing out of ppw
1418                    such as updating last write time */
1419                 page_data = kmap(page);
1420                 rc = cifs_write(file, page_data + offset, to-offset,
1421                                 &position);
1422                 if (rc > 0)
1423                         rc = 0;
1424                 /* else if (rc < 0) should we set writebehind rc? */
1425                 kunmap(page);
1426         } else {
1427                 set_page_dirty(page);
1428         }
1429
1430         FreeXid(xid);
1431         return rc;
1432 }
1433
1434 int cifs_fsync(struct file *file, struct dentry *dentry, int datasync)
1435 {
1436         int xid;
1437         int rc = 0;
1438         struct inode *inode = file->f_path.dentry->d_inode;
1439
1440         xid = GetXid();
1441
1442         cFYI(1, ("Sync file - name: %s datasync: 0x%x",
1443                 dentry->d_name.name, datasync));
1444
1445         rc = filemap_fdatawrite(inode->i_mapping);
1446         if (rc == 0)
1447                 CIFS_I(inode)->write_behind_rc = 0;
1448         FreeXid(xid);
1449         return rc;
1450 }
1451
1452 /* static void cifs_sync_page(struct page *page)
1453 {
1454         struct address_space *mapping;
1455         struct inode *inode;
1456         unsigned long index = page->index;
1457         unsigned int rpages = 0;
1458         int rc = 0;
1459
1460         cFYI(1, ("sync page %p",page));
1461         mapping = page->mapping;
1462         if (!mapping)
1463                 return 0;
1464         inode = mapping->host;
1465         if (!inode)
1466                 return; */
1467
1468 /*      fill in rpages then
1469         result = cifs_pagein_inode(inode, index, rpages); */ /* BB finish */
1470
1471 /*      cFYI(1, ("rpages is %d for sync page of Index %ld", rpages, index));
1472
1473 #if 0
1474         if (rc < 0)
1475                 return rc;
1476         return 0;
1477 #endif
1478 } */
1479
1480 /*
1481  * As file closes, flush all cached write data for this inode checking
1482  * for write behind errors.
1483  */
1484 int cifs_flush(struct file *file, fl_owner_t id)
1485 {
1486         struct inode * inode = file->f_path.dentry->d_inode;
1487         int rc = 0;
1488
1489         /* Rather than do the steps manually:
1490            lock the inode for writing
1491            loop through pages looking for write behind data (dirty pages)
1492            coalesce into contiguous 16K (or smaller) chunks to write to server
1493            send to server (prefer in parallel)
1494            deal with writebehind errors
1495            unlock inode for writing
1496            filemapfdatawrite appears easier for the time being */
1497
1498         rc = filemap_fdatawrite(inode->i_mapping);
1499         if (!rc) /* reset wb rc if we were able to write out dirty pages */
1500                 CIFS_I(inode)->write_behind_rc = 0;
1501
1502         cFYI(1, ("Flush inode %p file %p rc %d",inode,file,rc));
1503
1504         return rc;
1505 }
1506
1507 ssize_t cifs_user_read(struct file *file, char __user *read_data,
1508         size_t read_size, loff_t *poffset)
1509 {
1510         int rc = -EACCES;
1511         unsigned int bytes_read = 0;
1512         unsigned int total_read = 0;
1513         unsigned int current_read_size;
1514         struct cifs_sb_info *cifs_sb;
1515         struct cifsTconInfo *pTcon;
1516         int xid;
1517         struct cifsFileInfo *open_file;
1518         char *smb_read_data;
1519         char __user *current_offset;
1520         struct smb_com_read_rsp *pSMBr;
1521
1522         xid = GetXid();
1523         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1524         pTcon = cifs_sb->tcon;
1525
1526         if (file->private_data == NULL) {
1527                 FreeXid(xid);
1528                 return -EBADF;
1529         }
1530         open_file = (struct cifsFileInfo *)file->private_data;
1531
1532         if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
1533                 cFYI(1, ("attempting read on write only file instance"));
1534         }
1535         for (total_read = 0, current_offset = read_data;
1536              read_size > total_read;
1537              total_read += bytes_read, current_offset += bytes_read) {
1538                 current_read_size = min_t(const int, read_size - total_read,
1539                                           cifs_sb->rsize);
1540                 rc = -EAGAIN;
1541                 smb_read_data = NULL;
1542                 while (rc == -EAGAIN) {
1543                         int buf_type = CIFS_NO_BUFFER;
1544                         if ((open_file->invalidHandle) &&
1545                             (!open_file->closePend)) {
1546                                 rc = cifs_reopen_file(file->f_path.dentry->d_inode,
1547                                         file, TRUE);
1548                                 if (rc != 0)
1549                                         break;
1550                         }
1551                         rc = CIFSSMBRead(xid, pTcon,
1552                                          open_file->netfid,
1553                                          current_read_size, *poffset,
1554                                          &bytes_read, &smb_read_data,
1555                                          &buf_type);
1556                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
1557                         if (smb_read_data) {
1558                                 if (copy_to_user(current_offset,
1559                                                 smb_read_data +
1560                                                 4 /* RFC1001 length field */ +
1561                                                 le16_to_cpu(pSMBr->DataOffset),
1562                                                 bytes_read)) {
1563                                         rc = -EFAULT;
1564                                 }
1565
1566                                 if(buf_type == CIFS_SMALL_BUFFER)
1567                                         cifs_small_buf_release(smb_read_data);
1568                                 else if(buf_type == CIFS_LARGE_BUFFER)
1569                                         cifs_buf_release(smb_read_data);
1570                                 smb_read_data = NULL;
1571                         }
1572                 }
1573                 if (rc || (bytes_read == 0)) {
1574                         if (total_read) {
1575                                 break;
1576                         } else {
1577                                 FreeXid(xid);
1578                                 return rc;
1579                         }
1580                 } else {
1581                         cifs_stats_bytes_read(pTcon, bytes_read);
1582                         *poffset += bytes_read;
1583                 }
1584         }
1585         FreeXid(xid);
1586         return total_read;
1587 }
1588
1589
1590 static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
1591         loff_t *poffset)
1592 {
1593         int rc = -EACCES;
1594         unsigned int bytes_read = 0;
1595         unsigned int total_read;
1596         unsigned int current_read_size;
1597         struct cifs_sb_info *cifs_sb;
1598         struct cifsTconInfo *pTcon;
1599         int xid;
1600         char *current_offset;
1601         struct cifsFileInfo *open_file;
1602         int buf_type = CIFS_NO_BUFFER;
1603
1604         xid = GetXid();
1605         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1606         pTcon = cifs_sb->tcon;
1607
1608         if (file->private_data == NULL) {
1609                 FreeXid(xid);
1610                 return -EBADF;
1611         }
1612         open_file = (struct cifsFileInfo *)file->private_data;
1613
1614         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
1615                 cFYI(1, ("attempting read on write only file instance"));
1616
1617         for (total_read = 0, current_offset = read_data;
1618              read_size > total_read;
1619              total_read += bytes_read, current_offset += bytes_read) {
1620                 current_read_size = min_t(const int, read_size - total_read,
1621                                           cifs_sb->rsize);
1622                 /* For windows me and 9x we do not want to request more
1623                 than it negotiated since it will refuse the read then */
1624                 if((pTcon->ses) &&
1625                         !(pTcon->ses->capabilities & CAP_LARGE_FILES)) {
1626                         current_read_size = min_t(const int, current_read_size,
1627                                         pTcon->ses->server->maxBuf - 128);
1628                 }
1629                 rc = -EAGAIN;
1630                 while (rc == -EAGAIN) {
1631                         if ((open_file->invalidHandle) &&
1632                             (!open_file->closePend)) {
1633                                 rc = cifs_reopen_file(file->f_path.dentry->d_inode,
1634                                         file, TRUE);
1635                                 if (rc != 0)
1636                                         break;
1637                         }
1638                         rc = CIFSSMBRead(xid, pTcon,
1639                                          open_file->netfid,
1640                                          current_read_size, *poffset,
1641                                          &bytes_read, &current_offset,
1642                                          &buf_type);
1643                 }
1644                 if (rc || (bytes_read == 0)) {
1645                         if (total_read) {
1646                                 break;
1647                         } else {
1648                                 FreeXid(xid);
1649                                 return rc;
1650                         }
1651                 } else {
1652                         cifs_stats_bytes_read(pTcon, total_read);
1653                         *poffset += bytes_read;
1654                 }
1655         }
1656         FreeXid(xid);
1657         return total_read;
1658 }
1659
1660 int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
1661 {
1662         struct dentry *dentry = file->f_path.dentry;
1663         int rc, xid;
1664
1665         xid = GetXid();
1666         rc = cifs_revalidate(dentry);
1667         if (rc) {
1668                 cFYI(1, ("Validation prior to mmap failed, error=%d", rc));
1669                 FreeXid(xid);
1670                 return rc;
1671         }
1672         rc = generic_file_mmap(file, vma);
1673         FreeXid(xid);
1674         return rc;
1675 }
1676
1677
1678 static void cifs_copy_cache_pages(struct address_space *mapping,
1679         struct list_head *pages, int bytes_read, char *data,
1680         struct pagevec *plru_pvec)
1681 {
1682         struct page *page;
1683         char *target;
1684
1685         while (bytes_read > 0) {
1686                 if (list_empty(pages))
1687                         break;
1688
1689                 page = list_entry(pages->prev, struct page, lru);
1690                 list_del(&page->lru);
1691
1692                 if (add_to_page_cache(page, mapping, page->index,
1693                                       GFP_KERNEL)) {
1694                         page_cache_release(page);
1695                         cFYI(1, ("Add page cache failed"));
1696                         data += PAGE_CACHE_SIZE;
1697                         bytes_read -= PAGE_CACHE_SIZE;
1698                         continue;
1699                 }
1700
1701                 target = kmap_atomic(page,KM_USER0);
1702
1703                 if (PAGE_CACHE_SIZE > bytes_read) {
1704                         memcpy(target, data, bytes_read);
1705                         /* zero the tail end of this partial page */
1706                         memset(target + bytes_read, 0,
1707                                PAGE_CACHE_SIZE - bytes_read);
1708                         bytes_read = 0;
1709                 } else {
1710                         memcpy(target, data, PAGE_CACHE_SIZE);
1711                         bytes_read -= PAGE_CACHE_SIZE;
1712                 }
1713                 kunmap_atomic(target, KM_USER0);
1714
1715                 flush_dcache_page(page);
1716                 SetPageUptodate(page);
1717                 unlock_page(page);
1718                 if (!pagevec_add(plru_pvec, page))
1719                         __pagevec_lru_add(plru_pvec);
1720                 data += PAGE_CACHE_SIZE;
1721         }
1722         return;
1723 }
1724
1725 static int cifs_readpages(struct file *file, struct address_space *mapping,
1726         struct list_head *page_list, unsigned num_pages)
1727 {
1728         int rc = -EACCES;
1729         int xid;
1730         loff_t offset;
1731         struct page *page;
1732         struct cifs_sb_info *cifs_sb;
1733         struct cifsTconInfo *pTcon;
1734         int bytes_read = 0;
1735         unsigned int read_size,i;
1736         char *smb_read_data = NULL;
1737         struct smb_com_read_rsp *pSMBr;
1738         struct pagevec lru_pvec;
1739         struct cifsFileInfo *open_file;
1740         int buf_type = CIFS_NO_BUFFER;
1741
1742         xid = GetXid();
1743         if (file->private_data == NULL) {
1744                 FreeXid(xid);
1745                 return -EBADF;
1746         }
1747         open_file = (struct cifsFileInfo *)file->private_data;
1748         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1749         pTcon = cifs_sb->tcon;
1750
1751         pagevec_init(&lru_pvec, 0);
1752
1753         for (i = 0; i < num_pages; ) {
1754                 unsigned contig_pages;
1755                 struct page *tmp_page;
1756                 unsigned long expected_index;
1757
1758                 if (list_empty(page_list))
1759                         break;
1760
1761                 page = list_entry(page_list->prev, struct page, lru);
1762                 offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1763
1764                 /* count adjacent pages that we will read into */
1765                 contig_pages = 0;
1766                 expected_index =
1767                         list_entry(page_list->prev, struct page, lru)->index;
1768                 list_for_each_entry_reverse(tmp_page,page_list,lru) {
1769                         if (tmp_page->index == expected_index) {
1770                                 contig_pages++;
1771                                 expected_index++;
1772                         } else
1773                                 break;
1774                 }
1775                 if (contig_pages + i >  num_pages)
1776                         contig_pages = num_pages - i;
1777
1778                 /* for reads over a certain size could initiate async
1779                    read ahead */
1780
1781                 read_size = contig_pages * PAGE_CACHE_SIZE;
1782                 /* Read size needs to be in multiples of one page */
1783                 read_size = min_t(const unsigned int, read_size,
1784                                   cifs_sb->rsize & PAGE_CACHE_MASK);
1785
1786                 rc = -EAGAIN;
1787                 while (rc == -EAGAIN) {
1788                         if ((open_file->invalidHandle) &&
1789                             (!open_file->closePend)) {
1790                                 rc = cifs_reopen_file(file->f_path.dentry->d_inode,
1791                                         file, TRUE);
1792                                 if (rc != 0)
1793                                         break;
1794                         }
1795
1796                         rc = CIFSSMBRead(xid, pTcon,
1797                                          open_file->netfid,
1798                                          read_size, offset,
1799                                          &bytes_read, &smb_read_data,
1800                                          &buf_type);
1801                         /* BB more RC checks ? */
1802                         if (rc== -EAGAIN) {
1803                                 if (smb_read_data) {
1804                                         if(buf_type == CIFS_SMALL_BUFFER)
1805                                                 cifs_small_buf_release(smb_read_data);
1806                                         else if(buf_type == CIFS_LARGE_BUFFER)
1807                                                 cifs_buf_release(smb_read_data);
1808                                         smb_read_data = NULL;
1809                                 }
1810                         }
1811                 }
1812                 if ((rc < 0) || (smb_read_data == NULL)) {
1813                         cFYI(1, ("Read error in readpages: %d", rc));
1814                         break;
1815                 } else if (bytes_read > 0) {
1816                         task_io_account_read(bytes_read);
1817                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
1818                         cifs_copy_cache_pages(mapping, page_list, bytes_read,
1819                                 smb_read_data + 4 /* RFC1001 hdr */ +
1820                                 le16_to_cpu(pSMBr->DataOffset), &lru_pvec);
1821
1822                         i +=  bytes_read >> PAGE_CACHE_SHIFT;
1823                         cifs_stats_bytes_read(pTcon, bytes_read);
1824                         if ((int)(bytes_read & PAGE_CACHE_MASK) != bytes_read) {
1825                                 i++; /* account for partial page */
1826
1827                                 /* server copy of file can have smaller size
1828                                    than client */
1829                                 /* BB do we need to verify this common case ?
1830                                    this case is ok - if we are at server EOF
1831                                    we will hit it on next read */
1832
1833                                 /* break; */
1834                         }
1835                 } else {
1836                         cFYI(1, ("No bytes read (%d) at offset %lld . "
1837                                  "Cleaning remaining pages from readahead list",
1838                                  bytes_read, offset));
1839                         /* BB turn off caching and do new lookup on
1840                            file size at server? */
1841                         break;
1842                 }
1843                 if (smb_read_data) {
1844                         if(buf_type == CIFS_SMALL_BUFFER)
1845                                 cifs_small_buf_release(smb_read_data);
1846                         else if(buf_type == CIFS_LARGE_BUFFER)
1847                                 cifs_buf_release(smb_read_data);
1848                         smb_read_data = NULL;
1849                 }
1850                 bytes_read = 0;
1851         }
1852
1853         pagevec_lru_add(&lru_pvec);
1854
1855 /* need to free smb_read_data buf before exit */
1856         if (smb_read_data) {
1857                 if(buf_type == CIFS_SMALL_BUFFER)
1858                         cifs_small_buf_release(smb_read_data);
1859                 else if(buf_type == CIFS_LARGE_BUFFER)
1860                         cifs_buf_release(smb_read_data);
1861                 smb_read_data = NULL;
1862         }
1863
1864         FreeXid(xid);
1865         return rc;
1866 }
1867
1868 static int cifs_readpage_worker(struct file *file, struct page *page,
1869         loff_t *poffset)
1870 {
1871         char *read_data;
1872         int rc;
1873
1874         page_cache_get(page);
1875         read_data = kmap(page);
1876         /* for reads over a certain size could initiate async read ahead */
1877
1878         rc = cifs_read(file, read_data, PAGE_CACHE_SIZE, poffset);
1879
1880         if (rc < 0)
1881                 goto io_error;
1882         else
1883                 cFYI(1, ("Bytes read %d",rc));
1884
1885         file->f_path.dentry->d_inode->i_atime =
1886                 current_fs_time(file->f_path.dentry->d_inode->i_sb);
1887
1888         if (PAGE_CACHE_SIZE > rc)
1889                 memset(read_data + rc, 0, PAGE_CACHE_SIZE - rc);
1890
1891         flush_dcache_page(page);
1892         SetPageUptodate(page);
1893         rc = 0;
1894
1895 io_error:
1896         kunmap(page);
1897         page_cache_release(page);
1898         return rc;
1899 }
1900
1901 static int cifs_readpage(struct file *file, struct page *page)
1902 {
1903         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1904         int rc = -EACCES;
1905         int xid;
1906
1907         xid = GetXid();
1908
1909         if (file->private_data == NULL) {
1910                 FreeXid(xid);
1911                 return -EBADF;
1912         }
1913
1914         cFYI(1, ("readpage %p at offset %d 0x%x\n",
1915                  page, (int)offset, (int)offset));
1916
1917         rc = cifs_readpage_worker(file, page, &offset);
1918
1919         unlock_page(page);
1920
1921         FreeXid(xid);
1922         return rc;
1923 }
1924
1925 /* We do not want to update the file size from server for inodes
1926    open for write - to avoid races with writepage extending
1927    the file - in the future we could consider allowing
1928    refreshing the inode only on increases in the file size
1929    but this is tricky to do without racing with writebehind
1930    page caching in the current Linux kernel design */
1931 int is_size_safe_to_change(struct cifsInodeInfo *cifsInode)
1932 {
1933         struct cifsFileInfo *open_file = NULL;
1934
1935         if (cifsInode)
1936                 open_file =  find_writable_file(cifsInode);
1937
1938         if(open_file) {
1939                 struct cifs_sb_info *cifs_sb;
1940
1941                 /* there is not actually a write pending so let
1942                 this handle go free and allow it to
1943                 be closable if needed */
1944                 atomic_dec(&open_file->wrtPending);
1945
1946                 cifs_sb = CIFS_SB(cifsInode->vfs_inode.i_sb);
1947                 if ( cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO ) {
1948                         /* since no page cache to corrupt on directio
1949                         we can change size safely */
1950                         return 1;
1951                 }
1952
1953                 return 0;
1954         } else
1955                 return 1;
1956 }
1957
1958 static int cifs_prepare_write(struct file *file, struct page *page,
1959         unsigned from, unsigned to)
1960 {
1961         int rc = 0;
1962         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1963         cFYI(1, ("prepare write for page %p from %d to %d",page,from,to));
1964         if (!PageUptodate(page)) {
1965         /*      if (to - from != PAGE_CACHE_SIZE) {
1966                         void *kaddr = kmap_atomic(page, KM_USER0);
1967                         memset(kaddr, 0, from);
1968                         memset(kaddr + to, 0, PAGE_CACHE_SIZE - to);
1969                         flush_dcache_page(page);
1970                         kunmap_atomic(kaddr, KM_USER0);
1971                 } */
1972                 /* If we are writing a full page it will be up to date,
1973                    no need to read from the server */
1974                 if ((to == PAGE_CACHE_SIZE) && (from == 0))
1975                         SetPageUptodate(page);
1976
1977                 /* might as well read a page, it is fast enough */
1978                 if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
1979                         rc = cifs_readpage_worker(file, page, &offset);
1980                 } else {
1981                 /* should we try using another file handle if there is one -
1982                    how would we lock it to prevent close of that handle
1983                    racing with this read?
1984                    In any case this will be written out by commit_write */
1985                 }
1986         }
1987
1988         /* BB should we pass any errors back?
1989            e.g. if we do not have read access to the file */
1990         return 0;
1991 }
1992
1993 const struct address_space_operations cifs_addr_ops = {
1994         .readpage = cifs_readpage,
1995         .readpages = cifs_readpages,
1996         .writepage = cifs_writepage,
1997         .writepages = cifs_writepages,
1998         .prepare_write = cifs_prepare_write,
1999         .commit_write = cifs_commit_write,
2000         .set_page_dirty = __set_page_dirty_nobuffers,
2001         /* .sync_page = cifs_sync_page, */
2002         /* .direct_IO = */
2003 };
2004
2005 /*
2006  * cifs_readpages requires the server to support a buffer large enough to
2007  * contain the header plus one complete page of data.  Otherwise, we need
2008  * to leave cifs_readpages out of the address space operations.
2009  */
2010 const struct address_space_operations cifs_addr_ops_smallbuf = {
2011         .readpage = cifs_readpage,
2012         .writepage = cifs_writepage,
2013         .writepages = cifs_writepages,
2014         .prepare_write = cifs_prepare_write,
2015         .commit_write = cifs_commit_write,
2016         .set_page_dirty = __set_page_dirty_nobuffers,
2017         /* .sync_page = cifs_sync_page, */
2018         /* .direct_IO = */
2019 };