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., 2002,2007
   7  *   Author(s): Steve French (sfrench@us.ibm.com)
   8  *              Jeremy Allison (jra@samba.org)
   9  *
  10  *   This library is free software; you can redistribute it and/or modify
  11  *   it under the terms of the GNU Lesser General Public License as published
  12  *   by the Free Software Foundation; either version 2.1 of the License, or
  13  *   (at your option) any later version.
  14  *
  15  *   This library is distributed in the hope that it will be useful,
  16  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  18  *   the GNU Lesser General Public License for more details.
  19  *
  20  *   You should have received a copy of the GNU Lesser General Public License
  21  *   along with this library; if not, write to the Free Software
  22  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  */
  24 #include <linux/fs.h>
  25 #include <linux/backing-dev.h>
  26 #include <linux/stat.h>
  27 #include <linux/fcntl.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/pagevec.h>
  30 #include <linux/writeback.h>
  31 #include <linux/task_io_accounting_ops.h>
  32 #include <linux/delay.h>
  33 #include <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         mutex_init(&private_data->lock_mutex);
  51         INIT_LIST_HEAD(&private_data->llist);
  52         private_data->pfile = file; /* needed for writepage */
  53         private_data->pInode = inode;
  54         private_data->invalidHandle = FALSE;
  55         private_data->closePend = FALSE;
  56         /* we have to track num writers to the inode, since writepages
  57         does not tell us which handle the write is for so there can
  58         be a close (overlapping with write) of the filehandle that
  59         cifs_writepages chose to use */
  60         atomic_set(&private_data->wrtPending, 0);
  61
  62         return private_data;
  63 }
  64
  65 static inline int cifs_convert_flags(unsigned int flags)
  66 {
  67         if ((flags & O_ACCMODE) == O_RDONLY)
  68                 return GENERIC_READ;
  69         else if ((flags & O_ACCMODE) == O_WRONLY)
  70                 return GENERIC_WRITE;
  71         else if ((flags & O_ACCMODE) == O_RDWR) {
  72                 /* GENERIC_ALL is too much permission to request
  73                    can cause unnecessary access denied on create */
  74                 /* return GENERIC_ALL; */
  75                 return (GENERIC_READ | GENERIC_WRITE);
  76         }
  77
  78         return 0x20197;
  79 }
  80
  81 static inline int cifs_get_disposition(unsigned int flags)
  82 {
  83         if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
  84                 return FILE_CREATE;
  85         else if ((flags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
  86                 return FILE_OVERWRITE_IF;
  87         else if ((flags & O_CREAT) == O_CREAT)
  88                 return FILE_OPEN_IF;
  89         else if ((flags & O_TRUNC) == O_TRUNC)
  90                 return FILE_OVERWRITE;
  91         else
  92                 return FILE_OPEN;
  93 }
  94
  95 /* all arguments to this function must be checked for validity in caller */
  96 static inline int cifs_open_inode_helper(struct inode *inode, struct file *file,
  97         struct cifsInodeInfo *pCifsInode, struct cifsFileInfo *pCifsFile,
  98         struct cifsTconInfo *pTcon, int *oplock, FILE_ALL_INFO *buf,
  99         char *full_path, int xid)
 100 {
 101         struct timespec temp;
 102         int rc;
 103
 104         /* want handles we can use to read with first
 105            in the list so we do not have to walk the
 106            list to search for one in prepare_write */
 107         if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
 108                 list_add_tail(&pCifsFile->flist,
 109                               &pCifsInode->openFileList);
 110         } else {
 111                 list_add(&pCifsFile->flist,
 112                          &pCifsInode->openFileList);
 113         }
 114         write_unlock(&GlobalSMBSeslock);
 115         if (pCifsInode->clientCanCacheRead) {
 116                 /* we have the inode open somewhere else
 117                    no need to discard cache data */
 118                 goto client_can_cache;
 119         }
 120
 121         /* BB need same check in cifs_create too? */
 122         /* if not oplocked, invalidate inode pages if mtime or file
 123            size changed */
 124         temp = cifs_NTtimeToUnix(le64_to_cpu(buf->LastWriteTime));
 125         if (timespec_equal(&file->f_path.dentry->d_inode->i_mtime, &temp) &&
 126                            (file->f_path.dentry->d_inode->i_size ==
 127                             (loff_t)le64_to_cpu(buf->EndOfFile))) {
 128                 cFYI(1, ("inode unchanged on server"));
 129         } else {
 130                 if (file->f_path.dentry->d_inode->i_mapping) {
 131                 /* BB no need to lock inode until after invalidate
 132                    since namei code should already have it locked? */
 133                         filemap_write_and_wait(file->f_path.dentry->d_inode->i_mapping);
 134                 }
 135                 cFYI(1, ("invalidating remote inode since open detected it "
 136                          "changed"));
 137                 invalidate_remote_inode(file->f_path.dentry->d_inode);
 138         }
 139
 140 client_can_cache:
 141         if (pTcon->unix_ext)
 142                 rc = cifs_get_inode_info_unix(&file->f_path.dentry->d_inode,
 143                         full_path, inode->i_sb, xid);
 144         else
 145                 rc = cifs_get_inode_info(&file->f_path.dentry->d_inode,
 146                         full_path, buf, inode->i_sb, xid);
 147
 148         if ((*oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 149                 pCifsInode->clientCanCacheAll = TRUE;
 150                 pCifsInode->clientCanCacheRead = TRUE;
 151                 cFYI(1, ("Exclusive Oplock granted on inode %p",
 152                          file->f_path.dentry->d_inode));
 153         } else if ((*oplock & 0xF) == OPLOCK_READ)
 154                 pCifsInode->clientCanCacheRead = TRUE;
 155
 156         return rc;
 157 }
 158
 159 int cifs_open(struct inode *inode, struct file *file)
 160 {
 161         int rc = -EACCES;
 162         int xid, oplock;
 163         struct cifs_sb_info *cifs_sb;
 164         struct cifsTconInfo *pTcon;
 165         struct cifsFileInfo *pCifsFile;
 166         struct cifsInodeInfo *pCifsInode;
 167         struct list_head *tmp;
 168         char *full_path = NULL;
 169         int desiredAccess;
 170         int disposition;
 171         __u16 netfid;
 172         FILE_ALL_INFO *buf = NULL;
 173
 174         xid = GetXid();
 175
 176         cifs_sb = CIFS_SB(inode->i_sb);
 177         pTcon = cifs_sb->tcon;
 178
 179         if (file->f_flags & O_CREAT) {
 180                 /* search inode for this file and fill in file->private_data */
 181                 pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
 182                 read_lock(&GlobalSMBSeslock);
 183                 list_for_each(tmp, &pCifsInode->openFileList) {
 184                         pCifsFile = list_entry(tmp, struct cifsFileInfo,
 185                                                flist);
 186                         if ((pCifsFile->pfile == NULL) &&
 187                             (pCifsFile->pid == current->tgid)) {
 188                                 /* mode set in cifs_create */
 189
 190                                 /* needed for writepage */
 191                                 pCifsFile->pfile = file;
 192
 193                                 file->private_data = pCifsFile;
 194                                 break;
 195                         }
 196                 }
 197                 read_unlock(&GlobalSMBSeslock);
 198                 if (file->private_data != NULL) {
 199                         rc = 0;
 200                         FreeXid(xid);
 201                         return rc;
 202                 } else {
 203                         if (file->f_flags & O_EXCL)
 204                                 cERROR(1, ("could not find file instance for "
 205                                            "new file %p", file));
 206                 }
 207         }
 208
 209         full_path = build_path_from_dentry(file->f_path.dentry);
 210         if (full_path == NULL) {
 211                 FreeXid(xid);
 212                 return -ENOMEM;
 213         }
 214
 215         cFYI(1, ("inode = 0x%p file flags are 0x%x for %s",
 216                  inode, file->f_flags, full_path));
 217         desiredAccess = cifs_convert_flags(file->f_flags);
 218
 219 /*********************************************************************
 220  *  open flag mapping table:
 221  *
 222  *      POSIX Flag            CIFS Disposition
 223  *      ----------            ----------------
 224  *      O_CREAT               FILE_OPEN_IF
 225  *      O_CREAT | O_EXCL      FILE_CREATE
 226  *      O_CREAT | O_TRUNC     FILE_OVERWRITE_IF
 227  *      O_TRUNC               FILE_OVERWRITE
 228  *      none of the above     FILE_OPEN
 229  *
 230  *      Note that there is not a direct match between disposition
 231  *      FILE_SUPERSEDE (ie create whether or not file exists although
 232  *      O_CREAT | O_TRUNC is similar but truncates the existing
 233  *      file rather than creating a new file as FILE_SUPERSEDE does
 234  *      (which uses the attributes / metadata passed in on open call)
 235  *?
 236  *?  O_SYNC is a reasonable match to CIFS writethrough flag
 237  *?  and the read write flags match reasonably.  O_LARGEFILE
 238  *?  is irrelevant because largefile support is always used
 239  *?  by this client. Flags O_APPEND, O_DIRECT, O_DIRECTORY,
 240  *       O_FASYNC, O_NOFOLLOW, O_NONBLOCK need further investigation
 241  *********************************************************************/
 242
 243         disposition = cifs_get_disposition(file->f_flags);
 244
 245         if (oplockEnabled)
 246                 oplock = REQ_OPLOCK;
 247         else
 248                 oplock = FALSE;
 249
 250         /* BB pass O_SYNC flag through on file attributes .. BB */
 251
 252         /* Also refresh inode by passing in file_info buf returned by SMBOpen
 253            and calling get_inode_info with returned buf (at least helps
 254            non-Unix server case) */
 255
 256         /* BB we can not do this if this is the second open of a file
 257            and the first handle has writebehind data, we might be
 258            able to simply do a filemap_fdatawrite/filemap_fdatawait first */
 259         buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 260         if (!buf) {
 261                 rc = -ENOMEM;
 262                 goto out;
 263         }
 264
 265         if (cifs_sb->tcon->ses->capabilities & CAP_NT_SMBS)
 266                 rc = CIFSSMBOpen(xid, pTcon, full_path, disposition,
 267                          desiredAccess, CREATE_NOT_DIR, &netfid, &oplock, buf,
 268                          cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
 269                                  & CIFS_MOUNT_MAP_SPECIAL_CHR);
 270         else
 271                 rc = -EIO; /* no NT SMB support fall into legacy open below */
 272
 273         if (rc == -EIO) {
 274                 /* Old server, try legacy style OpenX */
 275                 rc = SMBLegacyOpen(xid, pTcon, full_path, disposition,
 276                         desiredAccess, CREATE_NOT_DIR, &netfid, &oplock, buf,
 277                         cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
 278                                 & CIFS_MOUNT_MAP_SPECIAL_CHR);
 279         }
 280         if (rc) {
 281                 cFYI(1, ("cifs_open returned 0x%x", rc));
 282                 goto out;
 283         }
 284         file->private_data =
 285                 kmalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 286         if (file->private_data == NULL) {
 287                 rc = -ENOMEM;
 288                 goto out;
 289         }
 290         pCifsFile = cifs_init_private(file->private_data, inode, file, netfid);
 291         write_lock(&GlobalSMBSeslock);
 292         list_add(&pCifsFile->tlist, &pTcon->openFileList);
 293
 294         pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
 295         if (pCifsInode) {
 296                 rc = cifs_open_inode_helper(inode, file, pCifsInode,
 297                                             pCifsFile, pTcon,
 298                                             &oplock, buf, full_path, xid);
 299         } else {
 300                 write_unlock(&GlobalSMBSeslock);
 301         }
 302
 303         if (oplock & CIFS_CREATE_ACTION) {
 304                 /* time to set mode which we can not set earlier due to
 305                    problems creating new read-only files */
 306                 if (pTcon->unix_ext) {
 307                         CIFSSMBUnixSetPerms(xid, pTcon, full_path,
 308                                             inode->i_mode,
 309                                             (__u64)-1, (__u64)-1, 0 /* dev */,
 310                                             cifs_sb->local_nls,
 311                                             cifs_sb->mnt_cifs_flags &
 312                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 313                 } else {
 314                         /* BB implement via Windows security descriptors eg
 315                            CIFSSMBWinSetPerms(xid, pTcon, full_path, mode,
 316                                               -1, -1, local_nls);
 317                            in the meantime could set r/o dos attribute when
 318                            perms are eg: mode & 0222 == 0 */
 319                 }
 320         }
 321
 322 out:
 323         kfree(buf);
 324         kfree(full_path);
 325         FreeXid(xid);
 326         return rc;
 327 }
 328
 329 /* Try to reacquire byte range locks that were released when session */
 330 /* to server was lost */
 331 static int cifs_relock_file(struct cifsFileInfo *cifsFile)
 332 {
 333         int rc = 0;
 334
 335 /* BB list all locks open on this file and relock */
 336
 337         return rc;
 338 }
 339
 340 static int cifs_reopen_file(struct file *file, int can_flush)
 341 {
 342         int rc = -EACCES;
 343         int xid, oplock;
 344         struct cifs_sb_info *cifs_sb;
 345         struct cifsTconInfo *pTcon;
 346         struct cifsFileInfo *pCifsFile;
 347         struct cifsInodeInfo *pCifsInode;
 348         struct inode *inode;
 349         char *full_path = NULL;
 350         int desiredAccess;
 351         int disposition = FILE_OPEN;
 352         __u16 netfid;
 353
 354         if (file->private_data) {
 355                 pCifsFile = (struct cifsFileInfo *)file->private_data;
 356         } else
 357                 return -EBADF;
 358
 359         xid = GetXid();
 360         down(&pCifsFile->fh_sem);
 361         if (pCifsFile->invalidHandle == FALSE) {
 362                 up(&pCifsFile->fh_sem);
 363                 FreeXid(xid);
 364                 return 0;
 365         }
 366
 367         if (file->f_path.dentry == NULL) {
 368                 cERROR(1, ("no valid name if dentry freed"));
 369                 dump_stack();
 370                 rc = -EBADF;
 371                 goto reopen_error_exit;
 372         }
 373
 374         inode = file->f_path.dentry->d_inode;
 375         if (inode == NULL) {
 376                 cERROR(1, ("inode not valid"));
 377                 dump_stack();
 378                 rc = -EBADF;
 379                 goto reopen_error_exit;
 380         }
 381
 382         cifs_sb = CIFS_SB(inode->i_sb);
 383         pTcon = cifs_sb->tcon;
 384
 385 /* can not grab rename sem here because various ops, including
 386    those that already have the rename sem can end up causing writepage
 387    to get called and if the server was down that means we end up here,
 388    and we can never tell if the caller already has the rename_sem */
 389         full_path = build_path_from_dentry(file->f_path.dentry);
 390         if (full_path == NULL) {
 391                 rc = -ENOMEM;
 392 reopen_error_exit:
 393                 up(&pCifsFile->fh_sem);
 394                 FreeXid(xid);
 395                 return rc;
 396         }
 397
 398         cFYI(1, ("inode = 0x%p file flags 0x%x for %s",
 399                  inode, file->f_flags, full_path));
 400         desiredAccess = cifs_convert_flags(file->f_flags);
 401
 402         if (oplockEnabled)
 403                 oplock = REQ_OPLOCK;
 404         else
 405                 oplock = FALSE;
 406
 407         /* Can not refresh inode by passing in file_info buf to be returned
 408            by SMBOpen and then calling get_inode_info with returned buf
 409            since file might have write behind data that needs to be flushed
 410            and server version of file size can be stale. If we knew for sure
 411            that inode was not dirty locally we could do this */
 412
 413         rc = CIFSSMBOpen(xid, pTcon, full_path, disposition, desiredAccess,
 414                          CREATE_NOT_DIR, &netfid, &oplock, NULL,
 415                          cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
 416                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 417         if (rc) {
 418                 up(&pCifsFile->fh_sem);
 419                 cFYI(1, ("cifs_open returned 0x%x", rc));
 420                 cFYI(1, ("oplock: %d", oplock));
 421         } else {
 422                 pCifsFile->netfid = netfid;
 423                 pCifsFile->invalidHandle = FALSE;
 424                 up(&pCifsFile->fh_sem);
 425                 pCifsInode = CIFS_I(inode);
 426                 if (pCifsInode) {
 427                         if (can_flush) {
 428                                 filemap_write_and_wait(inode->i_mapping);
 429                         /* temporarily disable caching while we
 430                            go to server to get inode info */
 431                                 pCifsInode->clientCanCacheAll = FALSE;
 432                                 pCifsInode->clientCanCacheRead = FALSE;
 433                                 if (pTcon->unix_ext)
 434                                         rc = cifs_get_inode_info_unix(&inode,
 435                                                 full_path, inode->i_sb, xid);
 436                                 else
 437                                         rc = cifs_get_inode_info(&inode,
 438                                                 full_path, NULL, inode->i_sb,
 439                                                 xid);
 440                         } /* else we are writing out data to server already
 441                              and could deadlock if we tried to flush data, and
 442                              since we do not know if we have data that would
 443                              invalidate the current end of file on the server
 444                              we can not go to the server to get the new inod
 445                              info */
 446                         if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 447                                 pCifsInode->clientCanCacheAll = TRUE;
 448                                 pCifsInode->clientCanCacheRead = TRUE;
 449                                 cFYI(1, ("Exclusive Oplock granted on inode %p",
 450                                          file->f_path.dentry->d_inode));
 451                         } else if ((oplock & 0xF) == OPLOCK_READ) {
 452                                 pCifsInode->clientCanCacheRead = TRUE;
 453                                 pCifsInode->clientCanCacheAll = FALSE;
 454                         } else {
 455                                 pCifsInode->clientCanCacheRead = FALSE;
 456                                 pCifsInode->clientCanCacheAll = FALSE;
 457                         }
 458                         cifs_relock_file(pCifsFile);
 459                 }
 460         }
 461
 462         kfree(full_path);
 463         FreeXid(xid);
 464         return rc;
 465 }
 466
 467 int cifs_close(struct inode *inode, struct file *file)
 468 {
 469         int rc = 0;
 470         int xid, timeout;
 471         struct cifs_sb_info *cifs_sb;
 472         struct cifsTconInfo *pTcon;
 473         struct cifsFileInfo *pSMBFile =
 474                 (struct cifsFileInfo *)file->private_data;
 475
 476         xid = GetXid();
 477
 478         cifs_sb = CIFS_SB(inode->i_sb);
 479         pTcon = cifs_sb->tcon;
 480         if (pSMBFile) {
 481                 struct cifsLockInfo *li, *tmp;
 482
 483                 pSMBFile->closePend = TRUE;
 484                 if (pTcon) {
 485                         /* no sense reconnecting to close a file that is
 486                            already closed */
 487                         if (pTcon->tidStatus != CifsNeedReconnect) {
 488                                 timeout = 2;
 489                                 while ((atomic_read(&pSMBFile->wrtPending) != 0)
 490                                         && (timeout <= 2048)) {
 491                                         /* Give write a better chance to get to
 492                                         server ahead of the close.  We do not
 493                                         want to add a wait_q here as it would
 494                                         increase the memory utilization as
 495                                         the struct would be in each open file,
 496                                         but this should give enough time to
 497                                         clear the socket */
 498 #ifdef CONFIG_CIFS_DEBUG2
 499                                         cFYI(1, ("close delay, write pending"));
 500 #endif /* DEBUG2 */
 501                                         msleep(timeout);
 502                                         timeout *= 4;
 503                                 }
 504                                 if (atomic_read(&pSMBFile->wrtPending))
 505                                         cERROR(1,
 506                                                 ("close with pending writes"));
 507                                 rc = CIFSSMBClose(xid, pTcon,
 508                                                   pSMBFile->netfid);
 509                         }
 510                 }
 511
 512                 /* Delete any outstanding lock records.
 513                    We'll lose them when the file is closed anyway. */
 514                 mutex_lock(&pSMBFile->lock_mutex);
 515                 list_for_each_entry_safe(li, tmp, &pSMBFile->llist, llist) {
 516                         list_del(&li->llist);
 517                         kfree(li);
 518                 }
 519                 mutex_unlock(&pSMBFile->lock_mutex);
 520
 521                 write_lock(&GlobalSMBSeslock);
 522                 list_del(&pSMBFile->flist);
 523                 list_del(&pSMBFile->tlist);
 524                 write_unlock(&GlobalSMBSeslock);
 525                 timeout = 10;
 526                 /* We waited above to give the SMBWrite a chance to issue
 527                    on the wire (so we do not get SMBWrite returning EBADF
 528                    if writepages is racing with close.  Note that writepages
 529                    does not specify a file handle, so it is possible for a file
 530                    to be opened twice, and the application close the "wrong"
 531                    file handle - in these cases we delay long enough to allow
 532                    the SMBWrite to get on the wire before the SMB Close.
 533                    We allow total wait here over 45 seconds, more than
 534                    oplock break time, and more than enough to allow any write
 535                    to complete on the server, or to time out on the client */
 536                 while ((atomic_read(&pSMBFile->wrtPending) != 0)
 537                                 && (timeout <= 50000)) {
 538                         cERROR(1, ("writes pending, delay free of handle"));
 539                         msleep(timeout);
 540                         timeout *= 8;
 541                 }
 542                 kfree(pSMBFile->search_resume_name);
 543                 kfree(file->private_data);
 544                 file->private_data = NULL;
 545         } else
 546                 rc = -EBADF;
 547
 548         read_lock(&GlobalSMBSeslock);
 549         if (list_empty(&(CIFS_I(inode)->openFileList))) {
 550                 cFYI(1, ("closing last open instance for inode %p", inode));
 551                 /* if the file is not open we do not know if we can cache info
 552                    on this inode, much less write behind and read ahead */
 553                 CIFS_I(inode)->clientCanCacheRead = FALSE;
 554                 CIFS_I(inode)->clientCanCacheAll  = FALSE;
 555         }
 556         read_unlock(&GlobalSMBSeslock);
 557         if ((rc == 0) && CIFS_I(inode)->write_behind_rc)
 558                 rc = CIFS_I(inode)->write_behind_rc;
 559         FreeXid(xid);
 560         return rc;
 561 }
 562
 563 int cifs_closedir(struct inode *inode, struct file *file)
 564 {
 565         int rc = 0;
 566         int xid;
 567         struct cifsFileInfo *pCFileStruct =
 568             (struct cifsFileInfo *)file->private_data;
 569         char *ptmp;
 570
 571         cFYI(1, ("Closedir inode = 0x%p", inode));
 572
 573         xid = GetXid();
 574
 575         if (pCFileStruct) {
 576                 struct cifsTconInfo *pTcon;
 577                 struct cifs_sb_info *cifs_sb =
 578                         CIFS_SB(file->f_path.dentry->d_sb);
 579
 580                 pTcon = cifs_sb->tcon;
 581
 582                 cFYI(1, ("Freeing private data in close dir"));
 583                 if ((pCFileStruct->srch_inf.endOfSearch == FALSE) &&
 584                    (pCFileStruct->invalidHandle == FALSE)) {
 585                         pCFileStruct->invalidHandle = TRUE;
 586                         rc = CIFSFindClose(xid, pTcon, pCFileStruct->netfid);
 587                         cFYI(1, ("Closing uncompleted readdir with rc %d",
 588                                  rc));
 589                         /* not much we can do if it fails anyway, ignore rc */
 590                         rc = 0;
 591                 }
 592                 ptmp = pCFileStruct->srch_inf.ntwrk_buf_start;
 593                 if (ptmp) {
 594                         cFYI(1, ("closedir free smb buf in srch struct"));
 595                         pCFileStruct->srch_inf.ntwrk_buf_start = NULL;
 596                         if (pCFileStruct->srch_inf.smallBuf)
 597                                 cifs_small_buf_release(ptmp);
 598                         else
 599                                 cifs_buf_release(ptmp);
 600                 }
 601                 ptmp = pCFileStruct->search_resume_name;
 602                 if (ptmp) {
 603                         cFYI(1, ("closedir free resume name"));
 604                         pCFileStruct->search_resume_name = NULL;
 605                         kfree(ptmp);
 606                 }
 607                 kfree(file->private_data);
 608                 file->private_data = NULL;
 609         }
 610         /* BB can we lock the filestruct while this is going on? */
 611         FreeXid(xid);
 612         return rc;
 613 }
 614
 615 static int store_file_lock(struct cifsFileInfo *fid, __u64 len,
 616                                 __u64 offset, __u8 lockType)
 617 {
 618         struct cifsLockInfo *li =
 619                 kmalloc(sizeof(struct cifsLockInfo), GFP_KERNEL);
 620         if (li == NULL)
 621                 return -ENOMEM;
 622         li->offset = offset;
 623         li->length = len;
 624         li->type = lockType;
 625         mutex_lock(&fid->lock_mutex);
 626         list_add(&li->llist, &fid->llist);
 627         mutex_unlock(&fid->lock_mutex);
 628         return 0;
 629 }
 630
 631 int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
 632 {
 633         int rc, xid;
 634         __u32 numLock = 0;
 635         __u32 numUnlock = 0;
 636         __u64 length;
 637         int wait_flag = FALSE;
 638         struct cifs_sb_info *cifs_sb;
 639         struct cifsTconInfo *pTcon;
 640         __u16 netfid;
 641         __u8 lockType = LOCKING_ANDX_LARGE_FILES;
 642         int posix_locking;
 643
 644         length = 1 + pfLock->fl_end - pfLock->fl_start;
 645         rc = -EACCES;
 646         xid = GetXid();
 647
 648         cFYI(1, ("Lock parm: 0x%x flockflags: "
 649                  "0x%x flocktype: 0x%x start: %lld end: %lld",
 650                 cmd, pfLock->fl_flags, pfLock->fl_type, pfLock->fl_start,
 651                 pfLock->fl_end));
 652
 653         if (pfLock->fl_flags & FL_POSIX)
 654                 cFYI(1, ("Posix"));
 655         if (pfLock->fl_flags & FL_FLOCK)
 656                 cFYI(1, ("Flock"));
 657         if (pfLock->fl_flags & FL_SLEEP) {
 658                 cFYI(1, ("Blocking lock"));
 659                 wait_flag = TRUE;
 660         }
 661         if (pfLock->fl_flags & FL_ACCESS)
 662                 cFYI(1, ("Process suspended by mandatory locking - "
 663                          "not implemented yet"));
 664         if (pfLock->fl_flags & FL_LEASE)
 665                 cFYI(1, ("Lease on file - not implemented yet"));
 666         if (pfLock->fl_flags &
 667             (~(FL_POSIX | FL_FLOCK | FL_SLEEP | FL_ACCESS | FL_LEASE)))
 668                 cFYI(1, ("Unknown lock flags 0x%x", pfLock->fl_flags));
 669
 670         if (pfLock->fl_type == F_WRLCK) {
 671                 cFYI(1, ("F_WRLCK "));
 672                 numLock = 1;
 673         } else if (pfLock->fl_type == F_UNLCK) {
 674                 cFYI(1, ("F_UNLCK"));
 675                 numUnlock = 1;
 676                 /* Check if unlock includes more than
 677                 one lock range */
 678         } else if (pfLock->fl_type == F_RDLCK) {
 679                 cFYI(1, ("F_RDLCK"));
 680                 lockType |= LOCKING_ANDX_SHARED_LOCK;
 681                 numLock = 1;
 682         } else if (pfLock->fl_type == F_EXLCK) {
 683                 cFYI(1, ("F_EXLCK"));
 684                 numLock = 1;
 685         } else if (pfLock->fl_type == F_SHLCK) {
 686                 cFYI(1, ("F_SHLCK"));
 687                 lockType |= LOCKING_ANDX_SHARED_LOCK;
 688                 numLock = 1;
 689         } else
 690                 cFYI(1, ("Unknown type of lock"));
 691
 692         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 693         pTcon = cifs_sb->tcon;
 694
 695         if (file->private_data == NULL) {
 696                 FreeXid(xid);
 697                 return -EBADF;
 698         }
 699         netfid = ((struct cifsFileInfo *)file->private_data)->netfid;
 700
 701         posix_locking = (cifs_sb->tcon->ses->capabilities & CAP_UNIX) &&
 702                         (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(cifs_sb->tcon->fsUnixInfo.Capability));
 703
 704         /* BB add code here to normalize offset and length to
 705         account for negative length which we can not accept over the
 706         wire */
 707         if (IS_GETLK(cmd)) {
 708                 if (posix_locking) {
 709                         int posix_lock_type;
 710                         if (lockType & LOCKING_ANDX_SHARED_LOCK)
 711                                 posix_lock_type = CIFS_RDLCK;
 712                         else
 713                                 posix_lock_type = CIFS_WRLCK;
 714                         rc = CIFSSMBPosixLock(xid, pTcon, netfid, 1 /* get */,
 715                                         length, pfLock,
 716                                         posix_lock_type, wait_flag);
 717                         FreeXid(xid);
 718                         return rc;
 719                 }
 720
 721                 /* BB we could chain these into one lock request BB */
 722                 rc = CIFSSMBLock(xid, pTcon, netfid, length, pfLock->fl_start,
 723                                  0, 1, lockType, 0 /* wait flag */ );
 724                 if (rc == 0) {
 725                         rc = CIFSSMBLock(xid, pTcon, netfid, length,
 726                                          pfLock->fl_start, 1 /* numUnlock */ ,
 727                                          0 /* numLock */ , lockType,
 728                                          0 /* wait flag */ );
 729                         pfLock->fl_type = F_UNLCK;
 730                         if (rc != 0)
 731                                 cERROR(1, ("Error unlocking previously locked "
 732                                            "range %d during test of lock", rc));
 733                         rc = 0;
 734
 735                 } else {
 736                         /* if rc == ERR_SHARING_VIOLATION ? */
 737                         rc = 0; /* do not change lock type to unlock
 738                                    since range in use */
 739                 }
 740
 741                 FreeXid(xid);
 742                 return rc;
 743         }
 744
 745         if (!numLock && !numUnlock) {
 746                 /* if no lock or unlock then nothing
 747                 to do since we do not know what it is */
 748                 FreeXid(xid);
 749                 return -EOPNOTSUPP;
 750         }
 751
 752         if (posix_locking) {
 753                 int posix_lock_type;
 754                 if (lockType & LOCKING_ANDX_SHARED_LOCK)
 755                         posix_lock_type = CIFS_RDLCK;
 756                 else
 757                         posix_lock_type = CIFS_WRLCK;
 758
 759                 if (numUnlock == 1)
 760                         posix_lock_type = CIFS_UNLCK;
 761
 762                 rc = CIFSSMBPosixLock(xid, pTcon, netfid, 0 /* set */,
 763                                       length, pfLock,
 764                                       posix_lock_type, wait_flag);
 765         } else {
 766                 struct cifsFileInfo *fid =
 767                         (struct cifsFileInfo *)file->private_data;
 768
 769                 if (numLock) {
 770                         rc = CIFSSMBLock(xid, pTcon, netfid, length,
 771                                         pfLock->fl_start,
 772                                         0, numLock, lockType, wait_flag);
 773
 774                         if (rc == 0) {
 775                                 /* For Windows locks we must store them. */
 776                                 rc = store_file_lock(fid, length,
 777                                                 pfLock->fl_start, lockType);
 778                         }
 779                 } else if (numUnlock) {
 780                         /* For each stored lock that this unlock overlaps
 781                            completely, unlock it. */
 782                         int stored_rc = 0;
 783                         struct cifsLockInfo *li, *tmp;
 784
 785                         rc = 0;
 786                         mutex_lock(&fid->lock_mutex);
 787                         list_for_each_entry_safe(li, tmp, &fid->llist, llist) {
 788                                 if (pfLock->fl_start <= li->offset &&
 789                                                 (pfLock->fl_start + length) >=
 790                                                 (li->offset + li->length)) {
 791                                         stored_rc = CIFSSMBLock(xid, pTcon,
 792                                                         netfid,
 793                                                         li->length, li->offset,
 794                                                         1, 0, li->type, FALSE);
 795                                         if (stored_rc)
 796                                                 rc = stored_rc;
 797
 798                                         list_del(&li->llist);
 799                                         kfree(li);
 800                                 }
 801                         }
 802                         mutex_unlock(&fid->lock_mutex);
 803                 }
 804         }
 805
 806         if (pfLock->fl_flags & FL_POSIX)
 807                 posix_lock_file_wait(file, pfLock);
 808         FreeXid(xid);
 809         return rc;
 810 }
 811
 812 ssize_t cifs_user_write(struct file *file, const char __user *write_data,
 813         size_t write_size, loff_t *poffset)
 814 {
 815         int rc = 0;
 816         unsigned int bytes_written = 0;
 817         unsigned int total_written;
 818         struct cifs_sb_info *cifs_sb;
 819         struct cifsTconInfo *pTcon;
 820         int xid, long_op;
 821         struct cifsFileInfo *open_file;
 822
 823         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 824
 825         pTcon = cifs_sb->tcon;
 826
 827         /* cFYI(1,
 828            (" write %d bytes to offset %lld of %s", write_size,
 829            *poffset, file->f_path.dentry->d_name.name)); */
 830
 831         if (file->private_data == NULL)
 832                 return -EBADF;
 833         open_file = (struct cifsFileInfo *) file->private_data;
 834
 835         xid = GetXid();
 836
 837         if (*poffset > file->f_path.dentry->d_inode->i_size)
 838                 long_op = 2; /* writes past end of file can take a long time */
 839         else
 840                 long_op = 1;
 841
 842         for (total_written = 0; write_size > total_written;
 843              total_written += bytes_written) {
 844                 rc = -EAGAIN;
 845                 while (rc == -EAGAIN) {
 846                         if (file->private_data == NULL) {
 847                                 /* file has been closed on us */
 848                                 FreeXid(xid);
 849                         /* if we have gotten here we have written some data
 850                            and blocked, and the file has been freed on us while
 851                            we blocked so return what we managed to write */
 852                                 return total_written;
 853                         }
 854                         if (open_file->closePend) {
 855                                 FreeXid(xid);
 856                                 if (total_written)
 857                                         return total_written;
 858                                 else
 859                                         return -EBADF;
 860                         }
 861                         if (open_file->invalidHandle) {
 862                                 /* we could deadlock if we called
 863                                    filemap_fdatawait from here so tell
 864                                    reopen_file not to flush data to server
 865                                    now */
 866                                 rc = cifs_reopen_file(file, FALSE);
 867                                 if (rc != 0)
 868                                         break;
 869                         }
 870
 871                         rc = CIFSSMBWrite(xid, pTcon,
 872                                 open_file->netfid,
 873                                 min_t(const int, cifs_sb->wsize,
 874                                       write_size - total_written),
 875                                 *poffset, &bytes_written,
 876                                 NULL, write_data + total_written, long_op);
 877                 }
 878                 if (rc || (bytes_written == 0)) {
 879                         if (total_written)
 880                                 break;
 881                         else {
 882                                 FreeXid(xid);
 883                                 return rc;
 884                         }
 885                 } else
 886                         *poffset += bytes_written;
 887                 long_op = FALSE; /* subsequent writes fast -
 888                                     15 seconds is plenty */
 889         }
 890
 891         cifs_stats_bytes_written(pTcon, total_written);
 892
 893         /* since the write may have blocked check these pointers again */
 894         if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
 895                 struct inode *inode = file->f_path.dentry->d_inode;
 896 /* Do not update local mtime - server will set its actual value on write
 897  *              inode->i_ctime = inode->i_mtime =
 898  *                      current_fs_time(inode->i_sb);*/
 899                 if (total_written > 0) {
 900                         spin_lock(&inode->i_lock);
 901                         if (*poffset > file->f_path.dentry->d_inode->i_size)
 902                                 i_size_write(file->f_path.dentry->d_inode,
 903                                         *poffset);
 904                         spin_unlock(&inode->i_lock);
 905                 }
 906                 mark_inode_dirty_sync(file->f_path.dentry->d_inode);
 907         }
 908         FreeXid(xid);
 909         return total_written;
 910 }
 911
 912 static ssize_t cifs_write(struct file *file, const char *write_data,
 913         size_t write_size, loff_t *poffset)
 914 {
 915         int rc = 0;
 916         unsigned int bytes_written = 0;
 917         unsigned int total_written;
 918         struct cifs_sb_info *cifs_sb;
 919         struct cifsTconInfo *pTcon;
 920         int xid, long_op;
 921         struct cifsFileInfo *open_file;
 922
 923         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 924
 925         pTcon = cifs_sb->tcon;
 926
 927         cFYI(1, ("write %zd bytes to offset %lld of %s", write_size,
 928            *poffset, file->f_path.dentry->d_name.name));
 929
 930         if (file->private_data == NULL)
 931                 return -EBADF;
 932         open_file = (struct cifsFileInfo *)file->private_data;
 933
 934         xid = GetXid();
 935
 936         if (*poffset > file->f_path.dentry->d_inode->i_size)
 937                 long_op = 2; /* writes past end of file can take a long time */
 938         else
 939                 long_op = 1;
 940
 941         for (total_written = 0; write_size > total_written;
 942              total_written += bytes_written) {
 943                 rc = -EAGAIN;
 944                 while (rc == -EAGAIN) {
 945                         if (file->private_data == NULL) {
 946                                 /* file has been closed on us */
 947                                 FreeXid(xid);
 948                         /* if we have gotten here we have written some data
 949                            and blocked, and the file has been freed on us
 950                            while we blocked so return what we managed to
 951                            write */
 952                                 return total_written;
 953                         }
 954                         if (open_file->closePend) {
 955                                 FreeXid(xid);
 956                                 if (total_written)
 957                                         return total_written;
 958                                 else
 959                                         return -EBADF;
 960                         }
 961                         if (open_file->invalidHandle) {
 962                                 /* we could deadlock if we called
 963                                    filemap_fdatawait from here so tell
 964                                    reopen_file not to flush data to
 965                                    server now */
 966                                 rc = cifs_reopen_file(file, FALSE);
 967                                 if (rc != 0)
 968                                         break;
 969                         }
 970                         if (experimEnabled || (pTcon->ses->server &&
 971                                 ((pTcon->ses->server->secMode &
 972                                 (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
 973                                 == 0))) {
 974                                 struct kvec iov[2];
 975                                 unsigned int len;
 976
 977                                 len = min((size_t)cifs_sb->wsize,
 978                                           write_size - total_written);
 979                                 /* iov[0] is reserved for smb header */
 980                                 iov[1].iov_base = (char *)write_data +
 981                                                   total_written;
 982                                 iov[1].iov_len = len;
 983                                 rc = CIFSSMBWrite2(xid, pTcon,
 984                                                 open_file->netfid, len,
 985                                                 *poffset, &bytes_written,
 986                                                 iov, 1, long_op);
 987                         } else
 988                                 rc = CIFSSMBWrite(xid, pTcon,
 989                                          open_file->netfid,
 990                                          min_t(const int, cifs_sb->wsize,
 991                                                write_size - total_written),
 992                                          *poffset, &bytes_written,
 993                                          write_data + total_written,
 994                                          NULL, long_op);
 995                 }
 996                 if (rc || (bytes_written == 0)) {
 997                         if (total_written)
 998                                 break;
 999                         else {
1000                                 FreeXid(xid);
1001                                 return rc;
1002                         }
1003                 } else
1004                         *poffset += bytes_written;
1005                 long_op = FALSE; /* subsequent writes fast -
1006                                     15 seconds is plenty */
1007         }
1008
1009         cifs_stats_bytes_written(pTcon, total_written);
1010
1011         /* since the write may have blocked check these pointers again */
1012         if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
1013 /*BB We could make this contingent on superblock ATIME flag too */
1014 /*              file->f_path.dentry->d_inode->i_ctime =
1015                 file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
1016                 if (total_written > 0) {
1017                         spin_lock(&file->f_path.dentry->d_inode->i_lock);
1018                         if (*poffset > file->f_path.dentry->d_inode->i_size)
1019                                 i_size_write(file->f_path.dentry->d_inode,
1020                                              *poffset);
1021                         spin_unlock(&file->f_path.dentry->d_inode->i_lock);
1022                 }
1023                 mark_inode_dirty_sync(file->f_path.dentry->d_inode);
1024         }
1025         FreeXid(xid);
1026         return total_written;
1027 }
1028
1029 struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode)
1030 {
1031         struct cifsFileInfo *open_file;
1032         int rc;
1033
1034         /* Having a null inode here (because mapping->host was set to zero by
1035         the VFS or MM) should not happen but we had reports of on oops (due to
1036         it being zero) during stress testcases so we need to check for it */
1037
1038         if (cifs_inode == NULL) {
1039                 cERROR(1, ("Null inode passed to cifs_writeable_file"));
1040                 dump_stack();
1041                 return NULL;
1042         }
1043
1044         read_lock(&GlobalSMBSeslock);
1045         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
1046                 if (open_file->closePend)
1047                         continue;
1048                 if (open_file->pfile &&
1049                     ((open_file->pfile->f_flags & O_RDWR) ||
1050                      (open_file->pfile->f_flags & O_WRONLY))) {
1051                         atomic_inc(&open_file->wrtPending);
1052                         read_unlock(&GlobalSMBSeslock);
1053                         if (open_file->invalidHandle) {
1054                                 rc = cifs_reopen_file(open_file->pfile, FALSE);
1055                                 /* if it fails, try another handle - might be */
1056                                 /* dangerous to hold up writepages with retry */
1057                                 if (rc) {
1058                                         cFYI(1, ("wp failed on reopen file"));
1059                                         read_lock(&GlobalSMBSeslock);
1060                                         /* can not use this handle, no write
1061                                         pending on this one after all */
1062                                         atomic_dec(&open_file->wrtPending);
1063                                         continue;
1064                                 }
1065                         }
1066                         if (open_file->closePend) {
1067                                 read_lock(&GlobalSMBSeslock);
1068                                 atomic_dec(&open_file->wrtPending);
1069                                 continue;
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;
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         iov = kmalloc(32 * sizeof(struct kvec), GFP_KERNEL);
1178         if (iov == NULL)
1179                 return generic_writepages(mapping, wbc);
1180
1181
1182         /*
1183          * BB: Is this meaningful for a non-block-device file system?
1184          * If it is, we should test it again after we do I/O
1185          */
1186         if (wbc->nonblocking && bdi_write_congested(bdi)) {
1187                 wbc->encountered_congestion = 1;
1188                 kfree(iov);
1189                 return 0;
1190         }
1191
1192         xid = GetXid();
1193
1194         pagevec_init(&pvec, 0);
1195         if (wbc->range_cyclic) {
1196                 index = mapping->writeback_index; /* Start from prev offset */
1197                 end = -1;
1198         } else {
1199                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
1200                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
1201                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
1202                         range_whole = 1;
1203                 scanned = 1;
1204         }
1205 retry:
1206         while (!done && (index <= end) &&
1207                (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
1208                         PAGECACHE_TAG_DIRTY,
1209                         min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1))) {
1210                 int first;
1211                 unsigned int i;
1212
1213                 first = -1;
1214                 next = 0;
1215                 n_iov = 0;
1216                 bytes_to_write = 0;
1217
1218                 for (i = 0; i < nr_pages; i++) {
1219                         page = pvec.pages[i];
1220                         /*
1221                          * At this point we hold neither mapping->tree_lock nor
1222                          * lock on the page itself: the page may be truncated or
1223                          * invalidated (changing page->mapping to NULL), or even
1224                          * swizzled back from swapper_space to tmpfs file
1225                          * mapping
1226                          */
1227
1228                         if (first < 0)
1229                                 lock_page(page);
1230                         else if (TestSetPageLocked(page))
1231                                 break;
1232
1233                         if (unlikely(page->mapping != mapping)) {
1234                                 unlock_page(page);
1235                                 break;
1236                         }
1237
1238                         if (!wbc->range_cyclic && page->index > end) {
1239                                 done = 1;
1240                                 unlock_page(page);
1241                                 break;
1242                         }
1243
1244                         if (next && (page->index != next)) {
1245                                 /* Not next consecutive page */
1246                                 unlock_page(page);
1247                                 break;
1248                         }
1249
1250                         if (wbc->sync_mode != WB_SYNC_NONE)
1251                                 wait_on_page_writeback(page);
1252
1253                         if (PageWriteback(page) ||
1254                                         !clear_page_dirty_for_io(page)) {
1255                                 unlock_page(page);
1256                                 break;
1257                         }
1258
1259                         /*
1260                          * This actually clears the dirty bit in the radix tree.
1261                          * See cifs_writepage() for more commentary.
1262                          */
1263                         set_page_writeback(page);
1264
1265                         if (page_offset(page) >= mapping->host->i_size) {
1266                                 done = 1;
1267                                 unlock_page(page);
1268                                 end_page_writeback(page);
1269                                 break;
1270                         }
1271
1272                         /*
1273                          * BB can we get rid of this?  pages are held by pvec
1274                          */
1275                         page_cache_get(page);
1276
1277                         len = min(mapping->host->i_size - page_offset(page),
1278                                   (loff_t)PAGE_CACHE_SIZE);
1279
1280                         /* reserve iov[0] for the smb header */
1281                         n_iov++;
1282                         iov[n_iov].iov_base = kmap(page);
1283                         iov[n_iov].iov_len = len;
1284                         bytes_to_write += len;
1285
1286                         if (first < 0) {
1287                                 first = i;
1288                                 offset = page_offset(page);
1289                         }
1290                         next = page->index + 1;
1291                         if (bytes_to_write + PAGE_CACHE_SIZE > cifs_sb->wsize)
1292                                 break;
1293                 }
1294                 if (n_iov) {
1295                         /* Search for a writable handle every time we call
1296                          * CIFSSMBWrite2.  We can't rely on the last handle
1297                          * we used to still be valid
1298                          */
1299                         open_file = find_writable_file(CIFS_I(mapping->host));
1300                         if (!open_file) {
1301                                 cERROR(1, ("No writable handles for inode"));
1302                                 rc = -EBADF;
1303                         } else {
1304                                 rc = CIFSSMBWrite2(xid, cifs_sb->tcon,
1305                                                    open_file->netfid,
1306                                                    bytes_to_write, offset,
1307                                                    &bytes_written, iov, n_iov,
1308                                                    1);
1309                                 atomic_dec(&open_file->wrtPending);
1310                                 if (rc || bytes_written < bytes_to_write) {
1311                                         cERROR(1, ("Write2 ret %d, wrote %d",
1312                                                   rc, bytes_written));
1313                                         /* BB what if continued retry is
1314                                            requested via mount flags? */
1315                                         set_bit(AS_EIO, &mapping->flags);
1316                                 } else {
1317                                         cifs_stats_bytes_written(cifs_sb->tcon,
1318                                                                  bytes_written);
1319                                 }
1320                         }
1321                         for (i = 0; i < n_iov; i++) {
1322                                 page = pvec.pages[first + i];
1323                                 /* Should we also set page error on
1324                                 success rc but too little data written? */
1325                                 /* BB investigate retry logic on temporary
1326                                 server crash cases and how recovery works
1327                                 when page marked as error */
1328                                 if (rc)
1329                                         SetPageError(page);
1330                                 kunmap(page);
1331                                 unlock_page(page);
1332                                 end_page_writeback(page);
1333                                 page_cache_release(page);
1334                         }
1335                         if ((wbc->nr_to_write -= n_iov) <= 0)
1336                                 done = 1;
1337                         index = next;
1338                 }
1339                 pagevec_release(&pvec);
1340         }
1341         if (!scanned && !done) {
1342                 /*
1343                  * We hit the last page and there is more work to be done: wrap
1344                  * back to the start of the file
1345                  */
1346                 scanned = 1;
1347                 index = 0;
1348                 goto retry;
1349         }
1350         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
1351                 mapping->writeback_index = index;
1352
1353         FreeXid(xid);
1354         kfree(iov);
1355         return rc;
1356 }
1357
1358 static int cifs_writepage(struct page *page, struct writeback_control *wbc)
1359 {
1360         int rc = -EFAULT;
1361         int xid;
1362
1363         xid = GetXid();
1364 /* BB add check for wbc flags */
1365         page_cache_get(page);
1366         if (!PageUptodate(page)) {
1367                 cFYI(1, ("ppw - page not up to date"));
1368         }
1369
1370         /*
1371          * Set the "writeback" flag, and clear "dirty" in the radix tree.
1372          *
1373          * A writepage() implementation always needs to do either this,
1374          * or re-dirty the page with "redirty_page_for_writepage()" in
1375          * the case of a failure.
1376          *
1377          * Just unlocking the page will cause the radix tree tag-bits
1378          * to fail to update with the state of the page correctly.
1379          */
1380         set_page_writeback(page);
1381         rc = cifs_partialpagewrite(page, 0, PAGE_CACHE_SIZE);
1382         SetPageUptodate(page); /* BB add check for error and Clearuptodate? */
1383         unlock_page(page);
1384         end_page_writeback(page);
1385         page_cache_release(page);
1386         FreeXid(xid);
1387         return rc;
1388 }
1389
1390 static int cifs_commit_write(struct file *file, struct page *page,
1391         unsigned offset, unsigned to)
1392 {
1393         int xid;
1394         int rc = 0;
1395         struct inode *inode = page->mapping->host;
1396         loff_t position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
1397         char *page_data;
1398
1399         xid = GetXid();
1400         cFYI(1, ("commit write for page %p up to position %lld for %d",
1401                  page, position, to));
1402         spin_lock(&inode->i_lock);
1403         if (position > inode->i_size) {
1404                 i_size_write(inode, position);
1405         }
1406         spin_unlock(&inode->i_lock);
1407         if (!PageUptodate(page)) {
1408                 position =  ((loff_t)page->index << PAGE_CACHE_SHIFT) + offset;
1409                 /* can not rely on (or let) writepage write this data */
1410                 if (to < offset) {
1411                         cFYI(1, ("Illegal offsets, can not copy from %d to %d",
1412                                 offset, to));
1413                         FreeXid(xid);
1414                         return rc;
1415                 }
1416                 /* this is probably better than directly calling
1417                    partialpage_write since in this function the file handle is
1418                    known which we might as well leverage */
1419                 /* BB check if anything else missing out of ppw
1420                    such as updating last write time */
1421                 page_data = kmap(page);
1422                 rc = cifs_write(file, page_data + offset, to-offset,
1423                                 &position);
1424                 if (rc > 0)
1425                         rc = 0;
1426                 /* else if (rc < 0) should we set writebehind rc? */
1427                 kunmap(page);
1428         } else {
1429                 set_page_dirty(page);
1430         }
1431
1432         FreeXid(xid);
1433         return rc;
1434 }
1435
1436 int cifs_fsync(struct file *file, struct dentry *dentry, int datasync)
1437 {
1438         int xid;
1439         int rc = 0;
1440         struct inode *inode = file->f_path.dentry->d_inode;
1441
1442         xid = GetXid();
1443
1444         cFYI(1, ("Sync file - name: %s datasync: 0x%x",
1445                 dentry->d_name.name, datasync));
1446
1447         rc = filemap_fdatawrite(inode->i_mapping);
1448         if (rc == 0)
1449                 CIFS_I(inode)->write_behind_rc = 0;
1450         FreeXid(xid);
1451         return rc;
1452 }
1453
1454 /* static void cifs_sync_page(struct page *page)
1455 {
1456         struct address_space *mapping;
1457         struct inode *inode;
1458         unsigned long index = page->index;
1459         unsigned int rpages = 0;
1460         int rc = 0;
1461
1462         cFYI(1, ("sync page %p",page));
1463         mapping = page->mapping;
1464         if (!mapping)
1465                 return 0;
1466         inode = mapping->host;
1467         if (!inode)
1468                 return; */
1469
1470 /*      fill in rpages then
1471         result = cifs_pagein_inode(inode, index, rpages); */ /* BB finish */
1472
1473 /*      cFYI(1, ("rpages is %d for sync page of Index %ld", rpages, index));
1474
1475 #if 0
1476         if (rc < 0)
1477                 return rc;
1478         return 0;
1479 #endif
1480 } */
1481
1482 /*
1483  * As file closes, flush all cached write data for this inode checking
1484  * for write behind errors.
1485  */
1486 int cifs_flush(struct file *file, fl_owner_t id)
1487 {
1488         struct inode *inode = file->f_path.dentry->d_inode;
1489         int rc = 0;
1490
1491         /* Rather than do the steps manually:
1492            lock the inode for writing
1493            loop through pages looking for write behind data (dirty pages)
1494            coalesce into contiguous 16K (or smaller) chunks to write to server
1495            send to server (prefer in parallel)
1496            deal with writebehind errors
1497            unlock inode for writing
1498            filemapfdatawrite appears easier for the time being */
1499
1500         rc = filemap_fdatawrite(inode->i_mapping);
1501         if (!rc) /* reset wb rc if we were able to write out dirty pages */
1502                 CIFS_I(inode)->write_behind_rc = 0;
1503
1504         cFYI(1, ("Flush inode %p file %p rc %d", inode, file, rc));
1505
1506         return rc;
1507 }
1508
1509 ssize_t cifs_user_read(struct file *file, char __user *read_data,
1510         size_t read_size, loff_t *poffset)
1511 {
1512         int rc = -EACCES;
1513         unsigned int bytes_read = 0;
1514         unsigned int total_read = 0;
1515         unsigned int current_read_size;
1516         struct cifs_sb_info *cifs_sb;
1517         struct cifsTconInfo *pTcon;
1518         int xid;
1519         struct cifsFileInfo *open_file;
1520         char *smb_read_data;
1521         char __user *current_offset;
1522         struct smb_com_read_rsp *pSMBr;
1523
1524         xid = GetXid();
1525         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1526         pTcon = cifs_sb->tcon;
1527
1528         if (file->private_data == NULL) {
1529                 FreeXid(xid);
1530                 return -EBADF;
1531         }
1532         open_file = (struct cifsFileInfo *)file->private_data;
1533
1534         if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
1535                 cFYI(1, ("attempting read on write only file instance"));
1536         }
1537         for (total_read = 0, current_offset = read_data;
1538              read_size > total_read;
1539              total_read += bytes_read, current_offset += bytes_read) {
1540                 current_read_size = min_t(const int, read_size - total_read,
1541                                           cifs_sb->rsize);
1542                 rc = -EAGAIN;
1543                 smb_read_data = NULL;
1544                 while (rc == -EAGAIN) {
1545                         int buf_type = CIFS_NO_BUFFER;
1546                         if ((open_file->invalidHandle) &&
1547                             (!open_file->closePend)) {
1548                                 rc = cifs_reopen_file(file, TRUE);
1549                                 if (rc != 0)
1550                                         break;
1551                         }
1552                         rc = CIFSSMBRead(xid, pTcon,
1553                                          open_file->netfid,
1554                                          current_read_size, *poffset,
1555                                          &bytes_read, &smb_read_data,
1556                                          &buf_type);
1557                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
1558                         if (smb_read_data) {
1559                                 if (copy_to_user(current_offset,
1560                                                 smb_read_data +
1561                                                 4 /* RFC1001 length field */ +
1562                                                 le16_to_cpu(pSMBr->DataOffset),
1563                                                 bytes_read)) {
1564                                         rc = -EFAULT;
1565                                 }
1566
1567                                 if (buf_type == CIFS_SMALL_BUFFER)
1568                                         cifs_small_buf_release(smb_read_data);
1569                                 else if (buf_type == CIFS_LARGE_BUFFER)
1570                                         cifs_buf_release(smb_read_data);
1571                                 smb_read_data = NULL;
1572                         }
1573                 }
1574                 if (rc || (bytes_read == 0)) {
1575                         if (total_read) {
1576                                 break;
1577                         } else {
1578                                 FreeXid(xid);
1579                                 return rc;
1580                         }
1581                 } else {
1582                         cifs_stats_bytes_read(pTcon, bytes_read);
1583                         *poffset += bytes_read;
1584                 }
1585         }
1586         FreeXid(xid);
1587         return total_read;
1588 }
1589
1590
1591 static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
1592         loff_t *poffset)
1593 {
1594         int rc = -EACCES;
1595         unsigned int bytes_read = 0;
1596         unsigned int total_read;
1597         unsigned int current_read_size;
1598         struct cifs_sb_info *cifs_sb;
1599         struct cifsTconInfo *pTcon;
1600         int xid;
1601         char *current_offset;
1602         struct cifsFileInfo *open_file;
1603         int buf_type = CIFS_NO_BUFFER;
1604
1605         xid = GetXid();
1606         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1607         pTcon = cifs_sb->tcon;
1608
1609         if (file->private_data == NULL) {
1610                 FreeXid(xid);
1611                 return -EBADF;
1612         }
1613         open_file = (struct cifsFileInfo *)file->private_data;
1614
1615         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
1616                 cFYI(1, ("attempting read on write only file instance"));
1617
1618         for (total_read = 0, current_offset = read_data;
1619              read_size > total_read;
1620              total_read += bytes_read, current_offset += bytes_read) {
1621                 current_read_size = min_t(const int, read_size - total_read,
1622                                           cifs_sb->rsize);
1623                 /* For windows me and 9x we do not want to request more
1624                 than it negotiated since it will refuse the read then */
1625                 if ((pTcon->ses) &&
1626                         !(pTcon->ses->capabilities & CAP_LARGE_FILES)) {
1627                         current_read_size = min_t(const int, current_read_size,
1628                                         pTcon->ses->server->maxBuf - 128);
1629                 }
1630                 rc = -EAGAIN;
1631                 while (rc == -EAGAIN) {
1632                         if ((open_file->invalidHandle) &&
1633                             (!open_file->closePend)) {
1634                                 rc = cifs_reopen_file(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 #ifdef CONFIG_CIFS_DEBUG2
1753                 cFYI(1, ("rpages: num pages %d", num_pages));
1754 #endif
1755         for (i = 0; i < num_pages; ) {
1756                 unsigned contig_pages;
1757                 struct page *tmp_page;
1758                 unsigned long expected_index;
1759
1760                 if (list_empty(page_list))
1761                         break;
1762
1763                 page = list_entry(page_list->prev, struct page, lru);
1764                 offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1765
1766                 /* count adjacent pages that we will read into */
1767                 contig_pages = 0;
1768                 expected_index =
1769                         list_entry(page_list->prev, struct page, lru)->index;
1770                 list_for_each_entry_reverse(tmp_page, page_list, lru) {
1771                         if (tmp_page->index == expected_index) {
1772                                 contig_pages++;
1773                                 expected_index++;
1774                         } else
1775                                 break;
1776                 }
1777                 if (contig_pages + i >  num_pages)
1778                         contig_pages = num_pages - i;
1779
1780                 /* for reads over a certain size could initiate async
1781                    read ahead */
1782
1783                 read_size = contig_pages * PAGE_CACHE_SIZE;
1784                 /* Read size needs to be in multiples of one page */
1785                 read_size = min_t(const unsigned int, read_size,
1786                                   cifs_sb->rsize & PAGE_CACHE_MASK);
1787 #ifdef CONFIG_CIFS_DEBUG2
1788                 cFYI(1, ("rpages: read size 0x%x  contiguous pages %d",
1789                                 read_size, contig_pages));
1790 #endif
1791                 rc = -EAGAIN;
1792                 while (rc == -EAGAIN) {
1793                         if ((open_file->invalidHandle) &&
1794                             (!open_file->closePend)) {
1795                                 rc = cifs_reopen_file(file, TRUE);
1796                                 if (rc != 0)
1797                                         break;
1798                         }
1799
1800                         rc = CIFSSMBRead(xid, pTcon,
1801                                          open_file->netfid,
1802                                          read_size, offset,
1803                                          &bytes_read, &smb_read_data,
1804                                          &buf_type);
1805                         /* BB more RC checks ? */
1806                         if (rc == -EAGAIN) {
1807                                 if (smb_read_data) {
1808                                         if (buf_type == CIFS_SMALL_BUFFER)
1809                                                 cifs_small_buf_release(smb_read_data);
1810                                         else if (buf_type == CIFS_LARGE_BUFFER)
1811                                                 cifs_buf_release(smb_read_data);
1812                                         smb_read_data = NULL;
1813                                 }
1814                         }
1815                 }
1816                 if ((rc < 0) || (smb_read_data == NULL)) {
1817                         cFYI(1, ("Read error in readpages: %d", rc));
1818                         break;
1819                 } else if (bytes_read > 0) {
1820                         task_io_account_read(bytes_read);
1821                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
1822                         cifs_copy_cache_pages(mapping, page_list, bytes_read,
1823                                 smb_read_data + 4 /* RFC1001 hdr */ +
1824                                 le16_to_cpu(pSMBr->DataOffset), &lru_pvec);
1825
1826                         i +=  bytes_read >> PAGE_CACHE_SHIFT;
1827                         cifs_stats_bytes_read(pTcon, bytes_read);
1828                         if ((int)(bytes_read & PAGE_CACHE_MASK) != bytes_read) {
1829                                 i++; /* account for partial page */
1830
1831                                 /* server copy of file can have smaller size
1832                                    than client */
1833                                 /* BB do we need to verify this common case ?
1834                                    this case is ok - if we are at server EOF
1835                                    we will hit it on next read */
1836
1837                                 /* break; */
1838                         }
1839                 } else {
1840                         cFYI(1, ("No bytes read (%d) at offset %lld . "
1841                                  "Cleaning remaining pages from readahead list",
1842                                  bytes_read, offset));
1843                         /* BB turn off caching and do new lookup on
1844                            file size at server? */
1845                         break;
1846                 }
1847                 if (smb_read_data) {
1848                         if (buf_type == CIFS_SMALL_BUFFER)
1849                                 cifs_small_buf_release(smb_read_data);
1850                         else if (buf_type == CIFS_LARGE_BUFFER)
1851                                 cifs_buf_release(smb_read_data);
1852                         smb_read_data = NULL;
1853                 }
1854                 bytes_read = 0;
1855         }
1856
1857         pagevec_lru_add(&lru_pvec);
1858
1859 /* need to free smb_read_data buf before exit */
1860         if (smb_read_data) {
1861                 if (buf_type == CIFS_SMALL_BUFFER)
1862                         cifs_small_buf_release(smb_read_data);
1863                 else if (buf_type == CIFS_LARGE_BUFFER)
1864                         cifs_buf_release(smb_read_data);
1865                 smb_read_data = NULL;
1866         }
1867
1868         FreeXid(xid);
1869         return rc;
1870 }
1871
1872 static int cifs_readpage_worker(struct file *file, struct page *page,
1873         loff_t *poffset)
1874 {
1875         char *read_data;
1876         int rc;
1877
1878         page_cache_get(page);
1879         read_data = kmap(page);
1880         /* for reads over a certain size could initiate async read ahead */
1881
1882         rc = cifs_read(file, read_data, PAGE_CACHE_SIZE, poffset);
1883
1884         if (rc < 0)
1885                 goto io_error;
1886         else
1887                 cFYI(1, ("Bytes read %d", rc));
1888
1889         file->f_path.dentry->d_inode->i_atime =
1890                 current_fs_time(file->f_path.dentry->d_inode->i_sb);
1891
1892         if (PAGE_CACHE_SIZE > rc)
1893                 memset(read_data + rc, 0, PAGE_CACHE_SIZE - rc);
1894
1895         flush_dcache_page(page);
1896         SetPageUptodate(page);
1897         rc = 0;
1898
1899 io_error:
1900         kunmap(page);
1901         page_cache_release(page);
1902         return rc;
1903 }
1904
1905 static int cifs_readpage(struct file *file, struct page *page)
1906 {
1907         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1908         int rc = -EACCES;
1909         int xid;
1910
1911         xid = GetXid();
1912
1913         if (file->private_data == NULL) {
1914                 FreeXid(xid);
1915                 return -EBADF;
1916         }
1917
1918         cFYI(1, ("readpage %p at offset %d 0x%x\n",
1919                  page, (int)offset, (int)offset));
1920
1921         rc = cifs_readpage_worker(file, page, &offset);
1922
1923         unlock_page(page);
1924
1925         FreeXid(xid);
1926         return rc;
1927 }
1928
1929 static int is_inode_writable(struct cifsInodeInfo *cifs_inode)
1930 {
1931         struct cifsFileInfo *open_file;
1932
1933         read_lock(&GlobalSMBSeslock);
1934         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
1935                 if (open_file->closePend)
1936                         continue;
1937                 if (open_file->pfile &&
1938                     ((open_file->pfile->f_flags & O_RDWR) ||
1939                      (open_file->pfile->f_flags & O_WRONLY))) {
1940                         read_unlock(&GlobalSMBSeslock);
1941                         return 1;
1942                 }
1943         }
1944         read_unlock(&GlobalSMBSeslock);
1945         return 0;
1946 }
1947
1948 /* We do not want to update the file size from server for inodes
1949    open for write - to avoid races with writepage extending
1950    the file - in the future we could consider allowing
1951    refreshing the inode only on increases in the file size
1952    but this is tricky to do without racing with writebehind
1953    page caching in the current Linux kernel design */
1954 int is_size_safe_to_change(struct cifsInodeInfo *cifsInode, __u64 end_of_file)
1955 {
1956         if (!cifsInode)
1957                 return 1;
1958
1959         if (is_inode_writable(cifsInode)) {
1960                 /* This inode is open for write at least once */
1961                 struct cifs_sb_info *cifs_sb;
1962
1963                 cifs_sb = CIFS_SB(cifsInode->vfs_inode.i_sb);
1964                 if ( cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO ) {
1965                         /* since no page cache to corrupt on directio
1966                         we can change size safely */
1967                         return 1;
1968                 }
1969
1970                 if (i_size_read(&cifsInode->vfs_inode) < end_of_file)
1971                         return 1;
1972
1973                 return 0;
1974         } else
1975                 return 1;
1976 }
1977
1978 static int cifs_prepare_write(struct file *file, struct page *page,
1979         unsigned from, unsigned to)
1980 {
1981         int rc = 0;
1982         loff_t i_size;
1983         loff_t offset;
1984
1985         cFYI(1, ("prepare write for page %p from %d to %d", page, from, to));
1986         if (PageUptodate(page))
1987                 return 0;
1988
1989         /* If we are writing a full page it will be up to date,
1990            no need to read from the server */
1991         if ((to == PAGE_CACHE_SIZE) && (from == 0)) {
1992                 SetPageUptodate(page);
1993                 return 0;
1994         }
1995
1996         offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1997         i_size = i_size_read(page->mapping->host);
1998
1999         if ((offset >= i_size) ||
2000             ((from == 0) && (offset + to) >= i_size)) {
2001                 /*
2002                  * We don't need to read data beyond the end of the file.
2003                  * zero it, and set the page uptodate
2004                  */
2005                 simple_prepare_write(file, page, from, to);
2006                 SetPageUptodate(page);
2007         } else if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
2008                 /* might as well read a page, it is fast enough */
2009                 rc = cifs_readpage_worker(file, page, &offset);
2010         } else {
2011                 /* we could try using another file handle if there is one -
2012                    but how would we lock it to prevent close of that handle
2013                    racing with this read? In any case
2014                    this will be written out by commit_write so is fine */
2015         }
2016
2017         /* we do not need to pass errors back
2018            e.g. if we do not have read access to the file
2019            because cifs_commit_write will do the right thing.  -- shaggy */
2020
2021         return 0;
2022 }
2023
2024 const struct address_space_operations cifs_addr_ops = {
2025         .readpage = cifs_readpage,
2026         .readpages = cifs_readpages,
2027         .writepage = cifs_writepage,
2028         .writepages = cifs_writepages,
2029         .prepare_write = cifs_prepare_write,
2030         .commit_write = cifs_commit_write,
2031         .set_page_dirty = __set_page_dirty_nobuffers,
2032         /* .sync_page = cifs_sync_page, */
2033         /* .direct_IO = */
2034 };
2035
2036 /*
2037  * cifs_readpages requires the server to support a buffer large enough to
2038  * contain the header plus one complete page of data.  Otherwise, we need
2039  * to leave cifs_readpages out of the address space operations.
2040  */
2041 const struct address_space_operations cifs_addr_ops_smallbuf = {
2042         .readpage = cifs_readpage,
2043         .writepage = cifs_writepage,
2044         .writepages = cifs_writepages,
2045         .prepare_write = cifs_prepare_write,
2046         .commit_write = cifs_commit_write,
2047         .set_page_dirty = __set_page_dirty_nobuffers,
2048         /* .sync_page = cifs_sync_page, */
2049         /* .direct_IO = */
2050 };