fs/cifs/file.c

   1 /*
   2  *   fs/cifs/file.c
   3  *
   4  *   vfs operations that deal with files
   5  *
   6  *   Copyright (C) International Business Machines  Corp., 2002,2010
   7  *   Author(s): Steve French (sfrench@us.ibm.com)
   8  *              Jeremy Allison (jra@samba.org)
   9  *
  10  *   This library is free software; you can redistribute it and/or modify
  11  *   it under the terms of the GNU Lesser General Public License as published
  12  *   by the Free Software Foundation; either version 2.1 of the License, or
  13  *   (at your option) any later version.
  14  *
  15  *   This library is distributed in the hope that it will be useful,
  16  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  18  *   the GNU Lesser General Public License for more details.
  19  *
  20  *   You should have received a copy of the GNU Lesser General Public License
  21  *   along with this library; if not, write to the Free Software
  22  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  */
  24 #include <linux/fs.h>
  25 #include <linux/backing-dev.h>
  26 #include <linux/stat.h>
  27 #include <linux/fcntl.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/pagevec.h>
  30 #include <linux/writeback.h>
  31 #include <linux/task_io_accounting_ops.h>
  32 #include <linux/delay.h>
  33 #include <linux/mount.h>
  34 #include <linux/slab.h>
  35 #include <asm/div64.h>
  36 #include "cifsfs.h"
  37 #include "cifspdu.h"
  38 #include "cifsglob.h"
  39 #include "cifsproto.h"
  40 #include "cifs_unicode.h"
  41 #include "cifs_debug.h"
  42 #include "cifs_fs_sb.h"
  43 #include "fscache.h"
  44
  45 static inline int cifs_convert_flags(unsigned int flags)
  46 {
  47         if ((flags & O_ACCMODE) == O_RDONLY)
  48                 return GENERIC_READ;
  49         else if ((flags & O_ACCMODE) == O_WRONLY)
  50                 return GENERIC_WRITE;
  51         else if ((flags & O_ACCMODE) == O_RDWR) {
  52                 /* GENERIC_ALL is too much permission to request
  53                    can cause unnecessary access denied on create */
  54                 /* return GENERIC_ALL; */
  55                 return (GENERIC_READ | GENERIC_WRITE);
  56         }
  57
  58         return (READ_CONTROL | FILE_WRITE_ATTRIBUTES | FILE_READ_ATTRIBUTES |
  59                 FILE_WRITE_EA | FILE_APPEND_DATA | FILE_WRITE_DATA |
  60                 FILE_READ_DATA);
  61 }
  62
  63 static inline fmode_t cifs_posix_convert_flags(unsigned int flags)
  64 {
  65         fmode_t posix_flags = 0;
  66
  67         if ((flags & O_ACCMODE) == O_RDONLY)
  68                 posix_flags = FMODE_READ;
  69         else if ((flags & O_ACCMODE) == O_WRONLY)
  70                 posix_flags = FMODE_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                 posix_flags = FMODE_READ | FMODE_WRITE;
  76         }
  77         /* can not map O_CREAT or O_EXCL or O_TRUNC flags when
  78            reopening a file.  They had their effect on the original open */
  79         if (flags & O_APPEND)
  80                 posix_flags |= (fmode_t)O_APPEND;
  81         if (flags & O_DSYNC)
  82                 posix_flags |= (fmode_t)O_DSYNC;
  83         if (flags & __O_SYNC)
  84                 posix_flags |= (fmode_t)__O_SYNC;
  85         if (flags & O_DIRECTORY)
  86                 posix_flags |= (fmode_t)O_DIRECTORY;
  87         if (flags & O_NOFOLLOW)
  88                 posix_flags |= (fmode_t)O_NOFOLLOW;
  89         if (flags & O_DIRECT)
  90                 posix_flags |= (fmode_t)O_DIRECT;
  91
  92         return posix_flags;
  93 }
  94
  95 static inline int cifs_get_disposition(unsigned int flags)
  96 {
  97         if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
  98                 return FILE_CREATE;
  99         else if ((flags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
 100                 return FILE_OVERWRITE_IF;
 101         else if ((flags & O_CREAT) == O_CREAT)
 102                 return FILE_OPEN_IF;
 103         else if ((flags & O_TRUNC) == O_TRUNC)
 104                 return FILE_OVERWRITE;
 105         else
 106                 return FILE_OPEN;
 107 }
 108
 109 /* all arguments to this function must be checked for validity in caller */
 110 static inline int
 111 cifs_posix_open_inode_helper(struct inode *inode, struct file *file,
 112                              struct cifsInodeInfo *pCifsInode, __u32 oplock,
 113                              u16 netfid)
 114 {
 115
 116         write_lock(&GlobalSMBSeslock);
 117
 118         pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
 119         if (pCifsInode == NULL) {
 120                 write_unlock(&GlobalSMBSeslock);
 121                 return -EINVAL;
 122         }
 123
 124         if (pCifsInode->clientCanCacheRead) {
 125                 /* we have the inode open somewhere else
 126                    no need to discard cache data */
 127                 goto psx_client_can_cache;
 128         }
 129
 130         /* BB FIXME need to fix this check to move it earlier into posix_open
 131            BB  fIX following section BB FIXME */
 132
 133         /* if not oplocked, invalidate inode pages if mtime or file
 134            size changed */
 135 /*      temp = cifs_NTtimeToUnix(le64_to_cpu(buf->LastWriteTime));
 136         if (timespec_equal(&file->f_path.dentry->d_inode->i_mtime, &temp) &&
 137                            (file->f_path.dentry->d_inode->i_size ==
 138                             (loff_t)le64_to_cpu(buf->EndOfFile))) {
 139                 cFYI(1, "inode unchanged on server");
 140         } else {
 141                 if (file->f_path.dentry->d_inode->i_mapping) {
 142                         rc = filemap_write_and_wait(file->f_path.dentry->d_inode->i_mapping);
 143                         if (rc != 0)
 144                                 CIFS_I(file->f_path.dentry->d_inode)->write_behind_rc = rc;
 145                 }
 146                 cFYI(1, "invalidating remote inode since open detected it "
 147                          "changed");
 148                 invalidate_remote_inode(file->f_path.dentry->d_inode);
 149         } */
 150
 151 psx_client_can_cache:
 152         if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 153                 pCifsInode->clientCanCacheAll = true;
 154                 pCifsInode->clientCanCacheRead = true;
 155                 cFYI(1, "Exclusive Oplock granted on inode %p",
 156                          file->f_path.dentry->d_inode);
 157         } else if ((oplock & 0xF) == OPLOCK_READ)
 158                 pCifsInode->clientCanCacheRead = true;
 159
 160         /* will have to change the unlock if we reenable the
 161            filemap_fdatawrite (which does not seem necessary */
 162         write_unlock(&GlobalSMBSeslock);
 163         return 0;
 164 }
 165
 166 /* all arguments to this function must be checked for validity in caller */
 167 static inline int cifs_open_inode_helper(struct inode *inode,
 168         struct cifsTconInfo *pTcon, __u32 oplock, FILE_ALL_INFO *buf,
 169         char *full_path, int xid)
 170 {
 171         struct cifsInodeInfo *pCifsInode = CIFS_I(inode);
 172         struct timespec temp;
 173         int rc;
 174
 175         if (pCifsInode->clientCanCacheRead) {
 176                 /* we have the inode open somewhere else
 177                    no need to discard cache data */
 178                 goto client_can_cache;
 179         }
 180
 181         /* BB need same check in cifs_create too? */
 182         /* if not oplocked, invalidate inode pages if mtime or file
 183            size changed */
 184         temp = cifs_NTtimeToUnix(buf->LastWriteTime);
 185         if (timespec_equal(&inode->i_mtime, &temp) &&
 186                            (inode->i_size ==
 187                             (loff_t)le64_to_cpu(buf->EndOfFile))) {
 188                 cFYI(1, "inode unchanged on server");
 189         } else {
 190                 if (inode->i_mapping) {
 191                         /* BB no need to lock inode until after invalidate
 192                         since namei code should already have it locked? */
 193                         rc = filemap_write_and_wait(inode->i_mapping);
 194                         if (rc != 0)
 195                                 pCifsInode->write_behind_rc = rc;
 196                 }
 197                 cFYI(1, "invalidating remote inode since open detected it "
 198                          "changed");
 199                 invalidate_remote_inode(inode);
 200         }
 201
 202 client_can_cache:
 203         if (pTcon->unix_ext)
 204                 rc = cifs_get_inode_info_unix(&inode, full_path, inode->i_sb,
 205                                               xid);
 206         else
 207                 rc = cifs_get_inode_info(&inode, full_path, buf, inode->i_sb,
 208                                          xid, NULL);
 209
 210         if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 211                 pCifsInode->clientCanCacheAll = true;
 212                 pCifsInode->clientCanCacheRead = true;
 213                 cFYI(1, "Exclusive Oplock granted on inode %p", inode);
 214         } else if ((oplock & 0xF) == OPLOCK_READ)
 215                 pCifsInode->clientCanCacheRead = true;
 216
 217         return rc;
 218 }
 219
 220 int cifs_open(struct inode *inode, struct file *file)
 221 {
 222         int rc = -EACCES;
 223         int xid;
 224         __u32 oplock;
 225         struct cifs_sb_info *cifs_sb;
 226         struct cifsTconInfo *tcon;
 227         struct tcon_link *tlink;
 228         struct cifsFileInfo *pCifsFile = NULL;
 229         struct cifsInodeInfo *pCifsInode;
 230         char *full_path = NULL;
 231         int desiredAccess;
 232         int disposition;
 233         __u16 netfid;
 234         FILE_ALL_INFO *buf = NULL;
 235
 236         xid = GetXid();
 237
 238         cifs_sb = CIFS_SB(inode->i_sb);
 239         tlink = cifs_sb_tlink(cifs_sb);
 240         if (IS_ERR(tlink)) {
 241                 FreeXid(xid);
 242                 return PTR_ERR(tlink);
 243         }
 244         tcon = tlink_tcon(tlink);
 245
 246         pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
 247
 248         full_path = build_path_from_dentry(file->f_path.dentry);
 249         if (full_path == NULL) {
 250                 rc = -ENOMEM;
 251                 goto out;
 252         }
 253
 254         cFYI(1, "inode = 0x%p file flags are 0x%x for %s",
 255                  inode, file->f_flags, full_path);
 256
 257         if (oplockEnabled)
 258                 oplock = REQ_OPLOCK;
 259         else
 260                 oplock = 0;
 261
 262         if (!tcon->broken_posix_open && tcon->unix_ext &&
 263             (tcon->ses->capabilities & CAP_UNIX) &&
 264             (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 265                         le64_to_cpu(tcon->fsUnixInfo.Capability))) {
 266                 int oflags = (int) cifs_posix_convert_flags(file->f_flags);
 267                 oflags |= SMB_O_CREAT;
 268                 /* can not refresh inode info since size could be stale */
 269                 rc = cifs_posix_open(full_path, &inode, inode->i_sb,
 270                                 cifs_sb->mnt_file_mode /* ignored */,
 271                                 oflags, &oplock, &netfid, xid);
 272                 if (rc == 0) {
 273                         cFYI(1, "posix open succeeded");
 274                         /* no need for special case handling of setting mode
 275                            on read only files needed here */
 276
 277                         rc = cifs_posix_open_inode_helper(inode, file,
 278                                         pCifsInode, oplock, netfid);
 279                         if (rc != 0) {
 280                                 CIFSSMBClose(xid, tcon, netfid);
 281                                 goto out;
 282                         }
 283
 284                         pCifsFile = cifs_new_fileinfo(inode, netfid, file,
 285                                                         file->f_path.mnt,
 286                                                         tlink, oflags, oplock);
 287                         if (pCifsFile == NULL) {
 288                                 CIFSSMBClose(xid, tcon, netfid);
 289                                 rc = -ENOMEM;
 290                         }
 291
 292                         cifs_fscache_set_inode_cookie(inode, file);
 293
 294                         goto out;
 295                 } else if ((rc == -EINVAL) || (rc == -EOPNOTSUPP)) {
 296                         if (tcon->ses->serverNOS)
 297                                 cERROR(1, "server %s of type %s returned"
 298                                            " unexpected error on SMB posix open"
 299                                            ", disabling posix open support."
 300                                            " Check if server update available.",
 301                                            tcon->ses->serverName,
 302                                            tcon->ses->serverNOS);
 303                         tcon->broken_posix_open = true;
 304                 } else if ((rc != -EIO) && (rc != -EREMOTE) &&
 305                          (rc != -EOPNOTSUPP)) /* path not found or net err */
 306                         goto out;
 307                 /* else fallthrough to retry open the old way on network i/o
 308                    or DFS errors */
 309         }
 310
 311         desiredAccess = cifs_convert_flags(file->f_flags);
 312
 313 /*********************************************************************
 314  *  open flag mapping table:
 315  *
 316  *      POSIX Flag            CIFS Disposition
 317  *      ----------            ----------------
 318  *      O_CREAT               FILE_OPEN_IF
 319  *      O_CREAT | O_EXCL      FILE_CREATE
 320  *      O_CREAT | O_TRUNC     FILE_OVERWRITE_IF
 321  *      O_TRUNC               FILE_OVERWRITE
 322  *      none of the above     FILE_OPEN
 323  *
 324  *      Note that there is not a direct match between disposition
 325  *      FILE_SUPERSEDE (ie create whether or not file exists although
 326  *      O_CREAT | O_TRUNC is similar but truncates the existing
 327  *      file rather than creating a new file as FILE_SUPERSEDE does
 328  *      (which uses the attributes / metadata passed in on open call)
 329  *?
 330  *?  O_SYNC is a reasonable match to CIFS writethrough flag
 331  *?  and the read write flags match reasonably.  O_LARGEFILE
 332  *?  is irrelevant because largefile support is always used
 333  *?  by this client. Flags O_APPEND, O_DIRECT, O_DIRECTORY,
 334  *       O_FASYNC, O_NOFOLLOW, O_NONBLOCK need further investigation
 335  *********************************************************************/
 336
 337         disposition = cifs_get_disposition(file->f_flags);
 338
 339         /* BB pass O_SYNC flag through on file attributes .. BB */
 340
 341         /* Also refresh inode by passing in file_info buf returned by SMBOpen
 342            and calling get_inode_info with returned buf (at least helps
 343            non-Unix server case) */
 344
 345         /* BB we can not do this if this is the second open of a file
 346            and the first handle has writebehind data, we might be
 347            able to simply do a filemap_fdatawrite/filemap_fdatawait first */
 348         buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
 349         if (!buf) {
 350                 rc = -ENOMEM;
 351                 goto out;
 352         }
 353
 354         if (tcon->ses->capabilities & CAP_NT_SMBS)
 355                 rc = CIFSSMBOpen(xid, tcon, full_path, disposition,
 356                          desiredAccess, CREATE_NOT_DIR, &netfid, &oplock, buf,
 357                          cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
 358                                  & CIFS_MOUNT_MAP_SPECIAL_CHR);
 359         else
 360                 rc = -EIO; /* no NT SMB support fall into legacy open below */
 361
 362         if (rc == -EIO) {
 363                 /* Old server, try legacy style OpenX */
 364                 rc = SMBLegacyOpen(xid, tcon, full_path, disposition,
 365                         desiredAccess, CREATE_NOT_DIR, &netfid, &oplock, buf,
 366                         cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
 367                                 & CIFS_MOUNT_MAP_SPECIAL_CHR);
 368         }
 369         if (rc) {
 370                 cFYI(1, "cifs_open returned 0x%x", rc);
 371                 goto out;
 372         }
 373
 374         rc = cifs_open_inode_helper(inode, tcon, oplock, buf, full_path, xid);
 375         if (rc != 0)
 376                 goto out;
 377
 378         pCifsFile = cifs_new_fileinfo(inode, netfid, file, file->f_path.mnt,
 379                                         tlink, file->f_flags, oplock);
 380         if (pCifsFile == NULL) {
 381                 rc = -ENOMEM;
 382                 goto out;
 383         }
 384
 385         cifs_fscache_set_inode_cookie(inode, file);
 386
 387         if (oplock & CIFS_CREATE_ACTION) {
 388                 /* time to set mode which we can not set earlier due to
 389                    problems creating new read-only files */
 390                 if (tcon->unix_ext) {
 391                         struct cifs_unix_set_info_args args = {
 392                                 .mode   = inode->i_mode,
 393                                 .uid    = NO_CHANGE_64,
 394                                 .gid    = NO_CHANGE_64,
 395                                 .ctime  = NO_CHANGE_64,
 396                                 .atime  = NO_CHANGE_64,
 397                                 .mtime  = NO_CHANGE_64,
 398                                 .device = 0,
 399                         };
 400                         CIFSSMBUnixSetPathInfo(xid, tcon, full_path, &args,
 401                                                cifs_sb->local_nls,
 402                                                cifs_sb->mnt_cifs_flags &
 403                                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 404                 }
 405         }
 406
 407 out:
 408         kfree(buf);
 409         kfree(full_path);
 410         FreeXid(xid);
 411         cifs_put_tlink(tlink);
 412         return rc;
 413 }
 414
 415 /* Try to reacquire byte range locks that were released when session */
 416 /* to server was lost */
 417 static int cifs_relock_file(struct cifsFileInfo *cifsFile)
 418 {
 419         int rc = 0;
 420
 421 /* BB list all locks open on this file and relock */
 422
 423         return rc;
 424 }
 425
 426 static int cifs_reopen_file(struct file *file, bool can_flush)
 427 {
 428         int rc = -EACCES;
 429         int xid;
 430         __u32 oplock;
 431         struct cifs_sb_info *cifs_sb;
 432         struct cifsTconInfo *tcon;
 433         struct cifsFileInfo *pCifsFile;
 434         struct cifsInodeInfo *pCifsInode;
 435         struct inode *inode;
 436         char *full_path = NULL;
 437         int desiredAccess;
 438         int disposition = FILE_OPEN;
 439         __u16 netfid;
 440
 441         if (file->private_data)
 442                 pCifsFile = file->private_data;
 443         else
 444                 return -EBADF;
 445
 446         xid = GetXid();
 447         mutex_lock(&pCifsFile->fh_mutex);
 448         if (!pCifsFile->invalidHandle) {
 449                 mutex_unlock(&pCifsFile->fh_mutex);
 450                 rc = 0;
 451                 FreeXid(xid);
 452                 return rc;
 453         }
 454
 455         if (file->f_path.dentry == NULL) {
 456                 cERROR(1, "no valid name if dentry freed");
 457                 dump_stack();
 458                 rc = -EBADF;
 459                 goto reopen_error_exit;
 460         }
 461
 462         inode = file->f_path.dentry->d_inode;
 463         if (inode == NULL) {
 464                 cERROR(1, "inode not valid");
 465                 dump_stack();
 466                 rc = -EBADF;
 467                 goto reopen_error_exit;
 468         }
 469
 470         cifs_sb = CIFS_SB(inode->i_sb);
 471         tcon = tlink_tcon(pCifsFile->tlink);
 472
 473 /* can not grab rename sem here because various ops, including
 474    those that already have the rename sem can end up causing writepage
 475    to get called and if the server was down that means we end up here,
 476    and we can never tell if the caller already has the rename_sem */
 477         full_path = build_path_from_dentry(file->f_path.dentry);
 478         if (full_path == NULL) {
 479                 rc = -ENOMEM;
 480 reopen_error_exit:
 481                 mutex_unlock(&pCifsFile->fh_mutex);
 482                 FreeXid(xid);
 483                 return rc;
 484         }
 485
 486         cFYI(1, "inode = 0x%p file flags 0x%x for %s",
 487                  inode, file->f_flags, full_path);
 488
 489         if (oplockEnabled)
 490                 oplock = REQ_OPLOCK;
 491         else
 492                 oplock = 0;
 493
 494         if (tcon->unix_ext && (tcon->ses->capabilities & CAP_UNIX) &&
 495             (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 496                         le64_to_cpu(tcon->fsUnixInfo.Capability))) {
 497                 int oflags = (int) cifs_posix_convert_flags(file->f_flags);
 498                 /* can not refresh inode info since size could be stale */
 499                 rc = cifs_posix_open(full_path, NULL, inode->i_sb,
 500                                 cifs_sb->mnt_file_mode /* ignored */,
 501                                 oflags, &oplock, &netfid, xid);
 502                 if (rc == 0) {
 503                         cFYI(1, "posix reopen succeeded");
 504                         goto reopen_success;
 505                 }
 506                 /* fallthrough to retry open the old way on errors, especially
 507                    in the reconnect path it is important to retry hard */
 508         }
 509
 510         desiredAccess = cifs_convert_flags(file->f_flags);
 511
 512         /* Can not refresh inode by passing in file_info buf to be returned
 513            by SMBOpen and then calling get_inode_info with returned buf
 514            since file might have write behind data that needs to be flushed
 515            and server version of file size can be stale. If we knew for sure
 516            that inode was not dirty locally we could do this */
 517
 518         rc = CIFSSMBOpen(xid, tcon, full_path, disposition, desiredAccess,
 519                          CREATE_NOT_DIR, &netfid, &oplock, NULL,
 520                          cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
 521                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
 522         if (rc) {
 523                 mutex_unlock(&pCifsFile->fh_mutex);
 524                 cFYI(1, "cifs_open returned 0x%x", rc);
 525                 cFYI(1, "oplock: %d", oplock);
 526         } else {
 527 reopen_success:
 528                 pCifsFile->netfid = netfid;
 529                 pCifsFile->invalidHandle = false;
 530                 mutex_unlock(&pCifsFile->fh_mutex);
 531                 pCifsInode = CIFS_I(inode);
 532                 if (pCifsInode) {
 533                         if (can_flush) {
 534                                 rc = filemap_write_and_wait(inode->i_mapping);
 535                                 if (rc != 0)
 536                                         CIFS_I(inode)->write_behind_rc = rc;
 537                         /* temporarily disable caching while we
 538                            go to server to get inode info */
 539                                 pCifsInode->clientCanCacheAll = false;
 540                                 pCifsInode->clientCanCacheRead = false;
 541                                 if (tcon->unix_ext)
 542                                         rc = cifs_get_inode_info_unix(&inode,
 543                                                 full_path, inode->i_sb, xid);
 544                                 else
 545                                         rc = cifs_get_inode_info(&inode,
 546                                                 full_path, NULL, inode->i_sb,
 547                                                 xid, NULL);
 548                         } /* else we are writing out data to server already
 549                              and could deadlock if we tried to flush data, and
 550                              since we do not know if we have data that would
 551                              invalidate the current end of file on the server
 552                              we can not go to the server to get the new inod
 553                              info */
 554                         if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
 555                                 pCifsInode->clientCanCacheAll = true;
 556                                 pCifsInode->clientCanCacheRead = true;
 557                                 cFYI(1, "Exclusive Oplock granted on inode %p",
 558                                          file->f_path.dentry->d_inode);
 559                         } else if ((oplock & 0xF) == OPLOCK_READ) {
 560                                 pCifsInode->clientCanCacheRead = true;
 561                                 pCifsInode->clientCanCacheAll = false;
 562                         } else {
 563                                 pCifsInode->clientCanCacheRead = false;
 564                                 pCifsInode->clientCanCacheAll = false;
 565                         }
 566                         cifs_relock_file(pCifsFile);
 567                 }
 568         }
 569         kfree(full_path);
 570         FreeXid(xid);
 571         return rc;
 572 }
 573
 574 int cifs_close(struct inode *inode, struct file *file)
 575 {
 576         int rc = 0;
 577         int xid, timeout;
 578         struct cifs_sb_info *cifs_sb;
 579         struct cifsTconInfo *pTcon;
 580         struct cifsFileInfo *pSMBFile = file->private_data;
 581
 582         xid = GetXid();
 583
 584         cifs_sb = CIFS_SB(inode->i_sb);
 585         pTcon = tlink_tcon(pSMBFile->tlink);
 586         if (pSMBFile) {
 587                 struct cifsLockInfo *li, *tmp;
 588                 write_lock(&GlobalSMBSeslock);
 589                 pSMBFile->closePend = true;
 590                 if (pTcon) {
 591                         /* no sense reconnecting to close a file that is
 592                            already closed */
 593                         if (!pTcon->need_reconnect) {
 594                                 write_unlock(&GlobalSMBSeslock);
 595                                 timeout = 2;
 596                                 while ((atomic_read(&pSMBFile->count) != 1)
 597                                         && (timeout <= 2048)) {
 598                                         /* Give write a better chance to get to
 599                                         server ahead of the close.  We do not
 600                                         want to add a wait_q here as it would
 601                                         increase the memory utilization as
 602                                         the struct would be in each open file,
 603                                         but this should give enough time to
 604                                         clear the socket */
 605                                         cFYI(DBG2, "close delay, write pending");
 606                                         msleep(timeout);
 607                                         timeout *= 4;
 608                                 }
 609                                 if (!pTcon->need_reconnect &&
 610                                     !pSMBFile->invalidHandle)
 611                                         rc = CIFSSMBClose(xid, pTcon,
 612                                                   pSMBFile->netfid);
 613                         } else
 614                                 write_unlock(&GlobalSMBSeslock);
 615                 } else
 616                         write_unlock(&GlobalSMBSeslock);
 617
 618                 /* Delete any outstanding lock records.
 619                    We'll lose them when the file is closed anyway. */
 620                 mutex_lock(&pSMBFile->lock_mutex);
 621                 list_for_each_entry_safe(li, tmp, &pSMBFile->llist, llist) {
 622                         list_del(&li->llist);
 623                         kfree(li);
 624                 }
 625                 mutex_unlock(&pSMBFile->lock_mutex);
 626
 627                 write_lock(&GlobalSMBSeslock);
 628                 list_del(&pSMBFile->flist);
 629                 list_del(&pSMBFile->tlist);
 630                 write_unlock(&GlobalSMBSeslock);
 631                 cifsFileInfo_put(file->private_data);
 632                 file->private_data = NULL;
 633         } else
 634                 rc = -EBADF;
 635
 636         read_lock(&GlobalSMBSeslock);
 637         if (list_empty(&(CIFS_I(inode)->openFileList))) {
 638                 cFYI(1, "closing last open instance for inode %p", inode);
 639                 /* if the file is not open we do not know if we can cache info
 640                    on this inode, much less write behind and read ahead */
 641                 CIFS_I(inode)->clientCanCacheRead = false;
 642                 CIFS_I(inode)->clientCanCacheAll  = false;
 643         }
 644         read_unlock(&GlobalSMBSeslock);
 645         if ((rc == 0) && CIFS_I(inode)->write_behind_rc)
 646                 rc = CIFS_I(inode)->write_behind_rc;
 647         FreeXid(xid);
 648         return rc;
 649 }
 650
 651 int cifs_closedir(struct inode *inode, struct file *file)
 652 {
 653         int rc = 0;
 654         int xid;
 655         struct cifsFileInfo *pCFileStruct = file->private_data;
 656         char *ptmp;
 657
 658         cFYI(1, "Closedir inode = 0x%p", inode);
 659
 660         xid = GetXid();
 661
 662         if (pCFileStruct) {
 663                 struct cifsTconInfo *pTcon = tlink_tcon(pCFileStruct->tlink);
 664
 665                 cFYI(1, "Freeing private data in close dir");
 666                 write_lock(&GlobalSMBSeslock);
 667                 if (!pCFileStruct->srch_inf.endOfSearch &&
 668                     !pCFileStruct->invalidHandle) {
 669                         pCFileStruct->invalidHandle = true;
 670                         write_unlock(&GlobalSMBSeslock);
 671                         rc = CIFSFindClose(xid, pTcon, pCFileStruct->netfid);
 672                         cFYI(1, "Closing uncompleted readdir with rc %d",
 673                                  rc);
 674                         /* not much we can do if it fails anyway, ignore rc */
 675                         rc = 0;
 676                 } else
 677                         write_unlock(&GlobalSMBSeslock);
 678                 ptmp = pCFileStruct->srch_inf.ntwrk_buf_start;
 679                 if (ptmp) {
 680                         cFYI(1, "closedir free smb buf in srch struct");
 681                         pCFileStruct->srch_inf.ntwrk_buf_start = NULL;
 682                         if (pCFileStruct->srch_inf.smallBuf)
 683                                 cifs_small_buf_release(ptmp);
 684                         else
 685                                 cifs_buf_release(ptmp);
 686                 }
 687                 cifs_put_tlink(pCFileStruct->tlink);
 688                 kfree(file->private_data);
 689                 file->private_data = NULL;
 690         }
 691         /* BB can we lock the filestruct while this is going on? */
 692         FreeXid(xid);
 693         return rc;
 694 }
 695
 696 static int store_file_lock(struct cifsFileInfo *fid, __u64 len,
 697                                 __u64 offset, __u8 lockType)
 698 {
 699         struct cifsLockInfo *li =
 700                 kmalloc(sizeof(struct cifsLockInfo), GFP_KERNEL);
 701         if (li == NULL)
 702                 return -ENOMEM;
 703         li->offset = offset;
 704         li->length = len;
 705         li->type = lockType;
 706         mutex_lock(&fid->lock_mutex);
 707         list_add(&li->llist, &fid->llist);
 708         mutex_unlock(&fid->lock_mutex);
 709         return 0;
 710 }
 711
 712 int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
 713 {
 714         int rc, xid;
 715         __u32 numLock = 0;
 716         __u32 numUnlock = 0;
 717         __u64 length;
 718         bool wait_flag = false;
 719         struct cifs_sb_info *cifs_sb;
 720         struct cifsTconInfo *tcon;
 721         __u16 netfid;
 722         __u8 lockType = LOCKING_ANDX_LARGE_FILES;
 723         bool posix_locking = 0;
 724
 725         length = 1 + pfLock->fl_end - pfLock->fl_start;
 726         rc = -EACCES;
 727         xid = GetXid();
 728
 729         cFYI(1, "Lock parm: 0x%x flockflags: "
 730                  "0x%x flocktype: 0x%x start: %lld end: %lld",
 731                 cmd, pfLock->fl_flags, pfLock->fl_type, pfLock->fl_start,
 732                 pfLock->fl_end);
 733
 734         if (pfLock->fl_flags & FL_POSIX)
 735                 cFYI(1, "Posix");
 736         if (pfLock->fl_flags & FL_FLOCK)
 737                 cFYI(1, "Flock");
 738         if (pfLock->fl_flags & FL_SLEEP) {
 739                 cFYI(1, "Blocking lock");
 740                 wait_flag = true;
 741         }
 742         if (pfLock->fl_flags & FL_ACCESS)
 743                 cFYI(1, "Process suspended by mandatory locking - "
 744                          "not implemented yet");
 745         if (pfLock->fl_flags & FL_LEASE)
 746                 cFYI(1, "Lease on file - not implemented yet");
 747         if (pfLock->fl_flags &
 748             (~(FL_POSIX | FL_FLOCK | FL_SLEEP | FL_ACCESS | FL_LEASE)))
 749                 cFYI(1, "Unknown lock flags 0x%x", pfLock->fl_flags);
 750
 751         if (pfLock->fl_type == F_WRLCK) {
 752                 cFYI(1, "F_WRLCK ");
 753                 numLock = 1;
 754         } else if (pfLock->fl_type == F_UNLCK) {
 755                 cFYI(1, "F_UNLCK");
 756                 numUnlock = 1;
 757                 /* Check if unlock includes more than
 758                 one lock range */
 759         } else if (pfLock->fl_type == F_RDLCK) {
 760                 cFYI(1, "F_RDLCK");
 761                 lockType |= LOCKING_ANDX_SHARED_LOCK;
 762                 numLock = 1;
 763         } else if (pfLock->fl_type == F_EXLCK) {
 764                 cFYI(1, "F_EXLCK");
 765                 numLock = 1;
 766         } else if (pfLock->fl_type == F_SHLCK) {
 767                 cFYI(1, "F_SHLCK");
 768                 lockType |= LOCKING_ANDX_SHARED_LOCK;
 769                 numLock = 1;
 770         } else
 771                 cFYI(1, "Unknown type of lock");
 772
 773         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 774         tcon = tlink_tcon(((struct cifsFileInfo *)file->private_data)->tlink);
 775
 776         if (file->private_data == NULL) {
 777                 rc = -EBADF;
 778                 FreeXid(xid);
 779                 return rc;
 780         }
 781         netfid = ((struct cifsFileInfo *)file->private_data)->netfid;
 782
 783         if ((tcon->ses->capabilities & CAP_UNIX) &&
 784             (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
 785             ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
 786                 posix_locking = 1;
 787         /* BB add code here to normalize offset and length to
 788         account for negative length which we can not accept over the
 789         wire */
 790         if (IS_GETLK(cmd)) {
 791                 if (posix_locking) {
 792                         int posix_lock_type;
 793                         if (lockType & LOCKING_ANDX_SHARED_LOCK)
 794                                 posix_lock_type = CIFS_RDLCK;
 795                         else
 796                                 posix_lock_type = CIFS_WRLCK;
 797                         rc = CIFSSMBPosixLock(xid, tcon, netfid, 1 /* get */,
 798                                         length, pfLock,
 799                                         posix_lock_type, wait_flag);
 800                         FreeXid(xid);
 801                         return rc;
 802                 }
 803
 804                 /* BB we could chain these into one lock request BB */
 805                 rc = CIFSSMBLock(xid, tcon, netfid, length, pfLock->fl_start,
 806                                  0, 1, lockType, 0 /* wait flag */ );
 807                 if (rc == 0) {
 808                         rc = CIFSSMBLock(xid, tcon, netfid, length,
 809                                          pfLock->fl_start, 1 /* numUnlock */ ,
 810                                          0 /* numLock */ , lockType,
 811                                          0 /* wait flag */ );
 812                         pfLock->fl_type = F_UNLCK;
 813                         if (rc != 0)
 814                                 cERROR(1, "Error unlocking previously locked "
 815                                            "range %d during test of lock", rc);
 816                         rc = 0;
 817
 818                 } else {
 819                         /* if rc == ERR_SHARING_VIOLATION ? */
 820                         rc = 0;
 821
 822                         if (lockType & LOCKING_ANDX_SHARED_LOCK) {
 823                                 pfLock->fl_type = F_WRLCK;
 824                         } else {
 825                                 rc = CIFSSMBLock(xid, tcon, netfid, length,
 826                                         pfLock->fl_start, 0, 1,
 827                                         lockType | LOCKING_ANDX_SHARED_LOCK,
 828                                         0 /* wait flag */);
 829                                 if (rc == 0) {
 830                                         rc = CIFSSMBLock(xid, tcon, netfid,
 831                                                 length, pfLock->fl_start, 1, 0,
 832                                                 lockType |
 833                                                 LOCKING_ANDX_SHARED_LOCK,
 834                                                 0 /* wait flag */);
 835                                         pfLock->fl_type = F_RDLCK;
 836                                         if (rc != 0)
 837                                                 cERROR(1, "Error unlocking "
 838                                                 "previously locked range %d "
 839                                                 "during test of lock", rc);
 840                                         rc = 0;
 841                                 } else {
 842                                         pfLock->fl_type = F_WRLCK;
 843                                         rc = 0;
 844                                 }
 845                         }
 846                 }
 847
 848                 FreeXid(xid);
 849                 return rc;
 850         }
 851
 852         if (!numLock && !numUnlock) {
 853                 /* if no lock or unlock then nothing
 854                 to do since we do not know what it is */
 855                 FreeXid(xid);
 856                 return -EOPNOTSUPP;
 857         }
 858
 859         if (posix_locking) {
 860                 int posix_lock_type;
 861                 if (lockType & LOCKING_ANDX_SHARED_LOCK)
 862                         posix_lock_type = CIFS_RDLCK;
 863                 else
 864                         posix_lock_type = CIFS_WRLCK;
 865
 866                 if (numUnlock == 1)
 867                         posix_lock_type = CIFS_UNLCK;
 868
 869                 rc = CIFSSMBPosixLock(xid, tcon, netfid, 0 /* set */,
 870                                       length, pfLock,
 871                                       posix_lock_type, wait_flag);
 872         } else {
 873                 struct cifsFileInfo *fid = file->private_data;
 874
 875                 if (numLock) {
 876                         rc = CIFSSMBLock(xid, tcon, netfid, length,
 877                                         pfLock->fl_start,
 878                                         0, numLock, lockType, wait_flag);
 879
 880                         if (rc == 0) {
 881                                 /* For Windows locks we must store them. */
 882                                 rc = store_file_lock(fid, length,
 883                                                 pfLock->fl_start, lockType);
 884                         }
 885                 } else if (numUnlock) {
 886                         /* For each stored lock that this unlock overlaps
 887                            completely, unlock it. */
 888                         int stored_rc = 0;
 889                         struct cifsLockInfo *li, *tmp;
 890
 891                         rc = 0;
 892                         mutex_lock(&fid->lock_mutex);
 893                         list_for_each_entry_safe(li, tmp, &fid->llist, llist) {
 894                                 if (pfLock->fl_start <= li->offset &&
 895                                                 (pfLock->fl_start + length) >=
 896                                                 (li->offset + li->length)) {
 897                                         stored_rc = CIFSSMBLock(xid, tcon,
 898                                                         netfid,
 899                                                         li->length, li->offset,
 900                                                         1, 0, li->type, false);
 901                                         if (stored_rc)
 902                                                 rc = stored_rc;
 903                                         else {
 904                                                 list_del(&li->llist);
 905                                                 kfree(li);
 906                                         }
 907                                 }
 908                         }
 909                         mutex_unlock(&fid->lock_mutex);
 910                 }
 911         }
 912
 913         if (pfLock->fl_flags & FL_POSIX)
 914                 posix_lock_file_wait(file, pfLock);
 915         FreeXid(xid);
 916         return rc;
 917 }
 918
 919 /*
 920  * Set the timeout on write requests past EOF. For some servers (Windows)
 921  * these calls can be very long.
 922  *
 923  * If we're writing >10M past the EOF we give a 180s timeout. Anything less
 924  * than that gets a 45s timeout. Writes not past EOF get 15s timeouts.
 925  * The 10M cutoff is totally arbitrary. A better scheme for this would be
 926  * welcome if someone wants to suggest one.
 927  *
 928  * We may be able to do a better job with this if there were some way to
 929  * declare that a file should be sparse.
 930  */
 931 static int
 932 cifs_write_timeout(struct cifsInodeInfo *cifsi, loff_t offset)
 933 {
 934         if (offset <= cifsi->server_eof)
 935                 return CIFS_STD_OP;
 936         else if (offset > (cifsi->server_eof + (10 * 1024 * 1024)))
 937                 return CIFS_VLONG_OP;
 938         else
 939                 return CIFS_LONG_OP;
 940 }
 941
 942 /* update the file size (if needed) after a write */
 943 static void
 944 cifs_update_eof(struct cifsInodeInfo *cifsi, loff_t offset,
 945                       unsigned int bytes_written)
 946 {
 947         loff_t end_of_write = offset + bytes_written;
 948
 949         if (end_of_write > cifsi->server_eof)
 950                 cifsi->server_eof = end_of_write;
 951 }
 952
 953 ssize_t cifs_user_write(struct file *file, const char __user *write_data,
 954         size_t write_size, loff_t *poffset)
 955 {
 956         int rc = 0;
 957         unsigned int bytes_written = 0;
 958         unsigned int total_written;
 959         struct cifs_sb_info *cifs_sb;
 960         struct cifsTconInfo *pTcon;
 961         int xid, long_op;
 962         struct cifsFileInfo *open_file;
 963         struct cifsInodeInfo *cifsi = CIFS_I(file->f_path.dentry->d_inode);
 964
 965         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 966
 967         /* cFYI(1, " write %d bytes to offset %lld of %s", write_size,
 968            *poffset, file->f_path.dentry->d_name.name); */
 969
 970         if (file->private_data == NULL)
 971                 return -EBADF;
 972
 973         open_file = file->private_data;
 974         pTcon = tlink_tcon(open_file->tlink);
 975
 976         rc = generic_write_checks(file, poffset, &write_size, 0);
 977         if (rc)
 978                 return rc;
 979
 980         xid = GetXid();
 981
 982         long_op = cifs_write_timeout(cifsi, *poffset);
 983         for (total_written = 0; write_size > total_written;
 984              total_written += bytes_written) {
 985                 rc = -EAGAIN;
 986                 while (rc == -EAGAIN) {
 987                         if (file->private_data == NULL) {
 988                                 /* file has been closed on us */
 989                                 FreeXid(xid);
 990                         /* if we have gotten here we have written some data
 991                            and blocked, and the file has been freed on us while
 992                            we blocked so return what we managed to write */
 993                                 return total_written;
 994                         }
 995                         if (open_file->closePend) {
 996                                 FreeXid(xid);
 997                                 if (total_written)
 998                                         return total_written;
 999                                 else
1000                                         return -EBADF;
1001                         }
1002                         if (open_file->invalidHandle) {
1003                                 /* we could deadlock if we called
1004                                    filemap_fdatawait from here so tell
1005                                    reopen_file not to flush data to server
1006                                    now */
1007                                 rc = cifs_reopen_file(file, false);
1008                                 if (rc != 0)
1009                                         break;
1010                         }
1011
1012                         rc = CIFSSMBWrite(xid, pTcon,
1013                                 open_file->netfid,
1014                                 min_t(const int, cifs_sb->wsize,
1015                                       write_size - total_written),
1016                                 *poffset, &bytes_written,
1017                                 NULL, write_data + total_written, long_op);
1018                 }
1019                 if (rc || (bytes_written == 0)) {
1020                         if (total_written)
1021                                 break;
1022                         else {
1023                                 FreeXid(xid);
1024                                 return rc;
1025                         }
1026                 } else {
1027                         cifs_update_eof(cifsi, *poffset, bytes_written);
1028                         *poffset += bytes_written;
1029                 }
1030                 long_op = CIFS_STD_OP; /* subsequent writes fast -
1031                                     15 seconds is plenty */
1032         }
1033
1034         cifs_stats_bytes_written(pTcon, total_written);
1035
1036         /* since the write may have blocked check these pointers again */
1037         if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
1038                 struct inode *inode = file->f_path.dentry->d_inode;
1039 /* Do not update local mtime - server will set its actual value on write
1040  *              inode->i_ctime = inode->i_mtime =
1041  *                      current_fs_time(inode->i_sb);*/
1042                 if (total_written > 0) {
1043                         spin_lock(&inode->i_lock);
1044                         if (*poffset > file->f_path.dentry->d_inode->i_size)
1045                                 i_size_write(file->f_path.dentry->d_inode,
1046                                         *poffset);
1047                         spin_unlock(&inode->i_lock);
1048                 }
1049                 mark_inode_dirty_sync(file->f_path.dentry->d_inode);
1050         }
1051         FreeXid(xid);
1052         return total_written;
1053 }
1054
1055 static ssize_t cifs_write(struct file *file, const char *write_data,
1056                           size_t write_size, loff_t *poffset)
1057 {
1058         int rc = 0;
1059         unsigned int bytes_written = 0;
1060         unsigned int total_written;
1061         struct cifs_sb_info *cifs_sb;
1062         struct cifsTconInfo *pTcon;
1063         int xid, long_op;
1064         struct cifsFileInfo *open_file;
1065         struct cifsInodeInfo *cifsi = CIFS_I(file->f_path.dentry->d_inode);
1066
1067         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1068
1069         cFYI(1, "write %zd bytes to offset %lld of %s", write_size,
1070            *poffset, file->f_path.dentry->d_name.name);
1071
1072         if (file->private_data == NULL)
1073                 return -EBADF;
1074         open_file = file->private_data;
1075         pTcon = tlink_tcon(open_file->tlink);
1076
1077         xid = GetXid();
1078
1079         long_op = cifs_write_timeout(cifsi, *poffset);
1080         for (total_written = 0; write_size > total_written;
1081              total_written += bytes_written) {
1082                 rc = -EAGAIN;
1083                 while (rc == -EAGAIN) {
1084                         if (file->private_data == NULL) {
1085                                 /* file has been closed on us */
1086                                 FreeXid(xid);
1087                         /* if we have gotten here we have written some data
1088                            and blocked, and the file has been freed on us
1089                            while we blocked so return what we managed to
1090                            write */
1091                                 return total_written;
1092                         }
1093                         if (open_file->closePend) {
1094                                 FreeXid(xid);
1095                                 if (total_written)
1096                                         return total_written;
1097                                 else
1098                                         return -EBADF;
1099                         }
1100                         if (open_file->invalidHandle) {
1101                                 /* we could deadlock if we called
1102                                    filemap_fdatawait from here so tell
1103                                    reopen_file not to flush data to
1104                                    server now */
1105                                 rc = cifs_reopen_file(file, false);
1106                                 if (rc != 0)
1107                                         break;
1108                         }
1109                         if (experimEnabled || (pTcon->ses->server &&
1110                                 ((pTcon->ses->server->secMode &
1111                                 (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
1112                                 == 0))) {
1113                                 struct kvec iov[2];
1114                                 unsigned int len;
1115
1116                                 len = min((size_t)cifs_sb->wsize,
1117                                           write_size - total_written);
1118                                 /* iov[0] is reserved for smb header */
1119                                 iov[1].iov_base = (char *)write_data +
1120                                                   total_written;
1121                                 iov[1].iov_len = len;
1122                                 rc = CIFSSMBWrite2(xid, pTcon,
1123                                                 open_file->netfid, len,
1124                                                 *poffset, &bytes_written,
1125                                                 iov, 1, long_op);
1126                         } else
1127                                 rc = CIFSSMBWrite(xid, pTcon,
1128                                          open_file->netfid,
1129                                          min_t(const int, cifs_sb->wsize,
1130                                                write_size - total_written),
1131                                          *poffset, &bytes_written,
1132                                          write_data + total_written,
1133                                          NULL, long_op);
1134                 }
1135                 if (rc || (bytes_written == 0)) {
1136                         if (total_written)
1137                                 break;
1138                         else {
1139                                 FreeXid(xid);
1140                                 return rc;
1141                         }
1142                 } else {
1143                         cifs_update_eof(cifsi, *poffset, bytes_written);
1144                         *poffset += bytes_written;
1145                 }
1146                 long_op = CIFS_STD_OP; /* subsequent writes fast -
1147                                     15 seconds is plenty */
1148         }
1149
1150         cifs_stats_bytes_written(pTcon, total_written);
1151
1152         /* since the write may have blocked check these pointers again */
1153         if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
1154 /*BB We could make this contingent on superblock ATIME flag too */
1155 /*              file->f_path.dentry->d_inode->i_ctime =
1156                 file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
1157                 if (total_written > 0) {
1158                         spin_lock(&file->f_path.dentry->d_inode->i_lock);
1159                         if (*poffset > file->f_path.dentry->d_inode->i_size)
1160                                 i_size_write(file->f_path.dentry->d_inode,
1161                                              *poffset);
1162                         spin_unlock(&file->f_path.dentry->d_inode->i_lock);
1163                 }
1164                 mark_inode_dirty_sync(file->f_path.dentry->d_inode);
1165         }
1166         FreeXid(xid);
1167         return total_written;
1168 }
1169
1170 #ifdef CONFIG_CIFS_EXPERIMENTAL
1171 struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode)
1172 {
1173         struct cifsFileInfo *open_file = NULL;
1174
1175         read_lock(&GlobalSMBSeslock);
1176         /* we could simply get the first_list_entry since write-only entries
1177            are always at the end of the list but since the first entry might
1178            have a close pending, we go through the whole list */
1179         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
1180                 if (open_file->closePend)
1181                         continue;
1182                 if (open_file->pfile && ((open_file->pfile->f_flags & O_RDWR) ||
1183                     (open_file->pfile->f_flags & O_RDONLY))) {
1184                         if (!open_file->invalidHandle) {
1185                                 /* found a good file */
1186                                 /* lock it so it will not be closed on us */
1187                                 cifsFileInfo_get(open_file);
1188                                 read_unlock(&GlobalSMBSeslock);
1189                                 return open_file;
1190                         } /* else might as well continue, and look for
1191                              another, or simply have the caller reopen it
1192                              again rather than trying to fix this handle */
1193                 } else /* write only file */
1194                         break; /* write only files are last so must be done */
1195         }
1196         read_unlock(&GlobalSMBSeslock);
1197         return NULL;
1198 }
1199 #endif
1200
1201 struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode)
1202 {
1203         struct cifsFileInfo *open_file;
1204         bool any_available = false;
1205         int rc;
1206
1207         /* Having a null inode here (because mapping->host was set to zero by
1208         the VFS or MM) should not happen but we had reports of on oops (due to
1209         it being zero) during stress testcases so we need to check for it */
1210
1211         if (cifs_inode == NULL) {
1212                 cERROR(1, "Null inode passed to cifs_writeable_file");
1213                 dump_stack();
1214                 return NULL;
1215         }
1216
1217         read_lock(&GlobalSMBSeslock);
1218 refind_writable:
1219         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
1220                 if (open_file->closePend ||
1221                     (!any_available && open_file->pid != current->tgid))
1222                         continue;
1223
1224                 if (open_file->pfile &&
1225                     ((open_file->pfile->f_flags & O_RDWR) ||
1226                      (open_file->pfile->f_flags & O_WRONLY))) {
1227                         cifsFileInfo_get(open_file);
1228
1229                         if (!open_file->invalidHandle) {
1230                                 /* found a good writable file */
1231                                 read_unlock(&GlobalSMBSeslock);
1232                                 return open_file;
1233                         }
1234
1235                         read_unlock(&GlobalSMBSeslock);
1236                         /* Had to unlock since following call can block */
1237                         rc = cifs_reopen_file(open_file->pfile, false);
1238                         if (!rc) {
1239                                 if (!open_file->closePend)
1240                                         return open_file;
1241                                 else { /* start over in case this was deleted */
1242                                        /* since the list could be modified */
1243                                         read_lock(&GlobalSMBSeslock);
1244                                         cifsFileInfo_put(open_file);
1245                                         goto refind_writable;
1246                                 }
1247                         }
1248
1249                         /* if it fails, try another handle if possible -
1250                         (we can not do this if closePending since
1251                         loop could be modified - in which case we
1252                         have to start at the beginning of the list
1253                         again. Note that it would be bad
1254                         to hold up writepages here (rather than
1255                         in caller) with continuous retries */
1256                         cFYI(1, "wp failed on reopen file");
1257                         read_lock(&GlobalSMBSeslock);
1258                         /* can not use this handle, no write
1259                            pending on this one after all */
1260                         cifsFileInfo_put(open_file);
1261
1262                         if (open_file->closePend) /* list could have changed */
1263                                 goto refind_writable;
1264                         /* else we simply continue to the next entry. Thus
1265                            we do not loop on reopen errors.  If we
1266                            can not reopen the file, for example if we
1267                            reconnected to a server with another client
1268                            racing to delete or lock the file we would not
1269                            make progress if we restarted before the beginning
1270                            of the loop here. */
1271                 }
1272         }
1273         /* couldn't find useable FH with same pid, try any available */
1274         if (!any_available) {
1275                 any_available = true;
1276                 goto refind_writable;
1277         }
1278         read_unlock(&GlobalSMBSeslock);
1279         return NULL;
1280 }
1281
1282 static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
1283 {
1284         struct address_space *mapping = page->mapping;
1285         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
1286         char *write_data;
1287         int rc = -EFAULT;
1288         int bytes_written = 0;
1289         struct cifs_sb_info *cifs_sb;
1290         struct inode *inode;
1291         struct cifsFileInfo *open_file;
1292
1293         if (!mapping || !mapping->host)
1294                 return -EFAULT;
1295
1296         inode = page->mapping->host;
1297         cifs_sb = CIFS_SB(inode->i_sb);
1298
1299         offset += (loff_t)from;
1300         write_data = kmap(page);
1301         write_data += from;
1302
1303         if ((to > PAGE_CACHE_SIZE) || (from > to)) {
1304                 kunmap(page);
1305                 return -EIO;
1306         }
1307
1308         /* racing with truncate? */
1309         if (offset > mapping->host->i_size) {
1310                 kunmap(page);
1311                 return 0; /* don't care */
1312         }
1313
1314         /* check to make sure that we are not extending the file */
1315         if (mapping->host->i_size - offset < (loff_t)to)
1316                 to = (unsigned)(mapping->host->i_size - offset);
1317
1318         open_file = find_writable_file(CIFS_I(mapping->host));
1319         if (open_file) {
1320                 bytes_written = cifs_write(open_file->pfile, write_data,
1321                                            to-from, &offset);
1322                 cifsFileInfo_put(open_file);
1323                 /* Does mm or vfs already set times? */
1324                 inode->i_atime = inode->i_mtime = current_fs_time(inode->i_sb);
1325                 if ((bytes_written > 0) && (offset))
1326                         rc = 0;
1327                 else if (bytes_written < 0)
1328                         rc = bytes_written;
1329         } else {
1330                 cFYI(1, "No writeable filehandles for inode");
1331                 rc = -EIO;
1332         }
1333
1334         kunmap(page);
1335         return rc;
1336 }
1337
1338 static int cifs_writepages(struct address_space *mapping,
1339                            struct writeback_control *wbc)
1340 {
1341         struct backing_dev_info *bdi = mapping->backing_dev_info;
1342         unsigned int bytes_to_write;
1343         unsigned int bytes_written;
1344         struct cifs_sb_info *cifs_sb;
1345         int done = 0;
1346         pgoff_t end;
1347         pgoff_t index;
1348         int range_whole = 0;
1349         struct kvec *iov;
1350         int len;
1351         int n_iov = 0;
1352         pgoff_t next;
1353         int nr_pages;
1354         __u64 offset = 0;
1355         struct cifsFileInfo *open_file;
1356         struct cifsTconInfo *tcon;
1357         struct cifsInodeInfo *cifsi = CIFS_I(mapping->host);
1358         struct page *page;
1359         struct pagevec pvec;
1360         int rc = 0;
1361         int scanned = 0;
1362         int xid, long_op;
1363
1364         /*
1365          * BB: Is this meaningful for a non-block-device file system?
1366          * If it is, we should test it again after we do I/O
1367          */
1368         if (wbc->nonblocking && bdi_write_congested(bdi)) {
1369                 wbc->encountered_congestion = 1;
1370                 return 0;
1371         }
1372
1373         cifs_sb = CIFS_SB(mapping->host->i_sb);
1374
1375         /*
1376          * If wsize is smaller that the page cache size, default to writing
1377          * one page at a time via cifs_writepage
1378          */
1379         if (cifs_sb->wsize < PAGE_CACHE_SIZE)
1380                 return generic_writepages(mapping, wbc);
1381
1382         iov = kmalloc(32 * sizeof(struct kvec), GFP_KERNEL);
1383         if (iov == NULL)
1384                 return generic_writepages(mapping, wbc);
1385
1386         /*
1387          * if there's no open file, then this is likely to fail too,
1388          * but it'll at least handle the return. Maybe it should be
1389          * a BUG() instead?
1390          */
1391         open_file = find_writable_file(CIFS_I(mapping->host));
1392         if (!open_file) {
1393                 kfree(iov);
1394                 return generic_writepages(mapping, wbc);
1395         }
1396
1397         tcon = tlink_tcon(open_file->tlink);
1398         if (!experimEnabled && tcon->ses->server->secMode &
1399                         (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
1400                 cifsFileInfo_put(open_file);
1401                 return generic_writepages(mapping, wbc);
1402         }
1403         cifsFileInfo_put(open_file);
1404
1405         xid = GetXid();
1406
1407         pagevec_init(&pvec, 0);
1408         if (wbc->range_cyclic) {
1409                 index = mapping->writeback_index; /* Start from prev offset */
1410                 end = -1;
1411         } else {
1412                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
1413                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
1414                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
1415                         range_whole = 1;
1416                 scanned = 1;
1417         }
1418 retry:
1419         while (!done && (index <= end) &&
1420                (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
1421                         PAGECACHE_TAG_DIRTY,
1422                         min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1))) {
1423                 int first;
1424                 unsigned int i;
1425
1426                 first = -1;
1427                 next = 0;
1428                 n_iov = 0;
1429                 bytes_to_write = 0;
1430
1431                 for (i = 0; i < nr_pages; i++) {
1432                         page = pvec.pages[i];
1433                         /*
1434                          * At this point we hold neither mapping->tree_lock nor
1435                          * lock on the page itself: the page may be truncated or
1436                          * invalidated (changing page->mapping to NULL), or even
1437                          * swizzled back from swapper_space to tmpfs file
1438                          * mapping
1439                          */
1440
1441                         if (first < 0)
1442                                 lock_page(page);
1443                         else if (!trylock_page(page))
1444                                 break;
1445
1446                         if (unlikely(page->mapping != mapping)) {
1447                                 unlock_page(page);
1448                                 break;
1449                         }
1450
1451                         if (!wbc->range_cyclic && page->index > end) {
1452                                 done = 1;
1453                                 unlock_page(page);
1454                                 break;
1455                         }
1456
1457                         if (next && (page->index != next)) {
1458                                 /* Not next consecutive page */
1459                                 unlock_page(page);
1460                                 break;
1461                         }
1462
1463                         if (wbc->sync_mode != WB_SYNC_NONE)
1464                                 wait_on_page_writeback(page);
1465
1466                         if (PageWriteback(page) ||
1467                                         !clear_page_dirty_for_io(page)) {
1468                                 unlock_page(page);
1469                                 break;
1470                         }
1471
1472                         /*
1473                          * This actually clears the dirty bit in the radix tree.
1474                          * See cifs_writepage() for more commentary.
1475                          */
1476                         set_page_writeback(page);
1477
1478                         if (page_offset(page) >= mapping->host->i_size) {
1479                                 done = 1;
1480                                 unlock_page(page);
1481                                 end_page_writeback(page);
1482                                 break;
1483                         }
1484
1485                         /*
1486                          * BB can we get rid of this?  pages are held by pvec
1487                          */
1488                         page_cache_get(page);
1489
1490                         len = min(mapping->host->i_size - page_offset(page),
1491                                   (loff_t)PAGE_CACHE_SIZE);
1492
1493                         /* reserve iov[0] for the smb header */
1494                         n_iov++;
1495                         iov[n_iov].iov_base = kmap(page);
1496                         iov[n_iov].iov_len = len;
1497                         bytes_to_write += len;
1498
1499                         if (first < 0) {
1500                                 first = i;
1501                                 offset = page_offset(page);
1502                         }
1503                         next = page->index + 1;
1504                         if (bytes_to_write + PAGE_CACHE_SIZE > cifs_sb->wsize)
1505                                 break;
1506                 }
1507                 if (n_iov) {
1508                         open_file = find_writable_file(CIFS_I(mapping->host));
1509                         if (!open_file) {
1510                                 cERROR(1, "No writable handles for inode");
1511                                 rc = -EBADF;
1512                         } else {
1513                                 long_op = cifs_write_timeout(cifsi, offset);
1514                                 rc = CIFSSMBWrite2(xid, tcon, open_file->netfid,
1515                                                    bytes_to_write, offset,
1516                                                    &bytes_written, iov, n_iov,
1517                                                    long_op);
1518                                 cifsFileInfo_put(open_file);
1519                                 cifs_update_eof(cifsi, offset, bytes_written);
1520                         }
1521
1522                         if (rc || bytes_written < bytes_to_write) {
1523                                 cERROR(1, "Write2 ret %d, wrote %d",
1524                                           rc, bytes_written);
1525                                 /* BB what if continued retry is
1526                                    requested via mount flags? */
1527                                 if (rc == -ENOSPC)
1528                                         set_bit(AS_ENOSPC, &mapping->flags);
1529                                 else
1530                                         set_bit(AS_EIO, &mapping->flags);
1531                         } else {
1532                                 cifs_stats_bytes_written(tcon, bytes_written);
1533                         }
1534
1535                         for (i = 0; i < n_iov; i++) {
1536                                 page = pvec.pages[first + i];
1537                                 /* Should we also set page error on
1538                                 success rc but too little data written? */
1539                                 /* BB investigate retry logic on temporary
1540                                 server crash cases and how recovery works
1541                                 when page marked as error */
1542                                 if (rc)
1543                                         SetPageError(page);
1544                                 kunmap(page);
1545                                 unlock_page(page);
1546                                 end_page_writeback(page);
1547                                 page_cache_release(page);
1548                         }
1549                         if ((wbc->nr_to_write -= n_iov) <= 0)
1550                                 done = 1;
1551                         index = next;
1552                 } else
1553                         /* Need to re-find the pages we skipped */
1554                         index = pvec.pages[0]->index + 1;
1555
1556                 pagevec_release(&pvec);
1557         }
1558         if (!scanned && !done) {
1559                 /*
1560                  * We hit the last page and there is more work to be done: wrap
1561                  * back to the start of the file
1562                  */
1563                 scanned = 1;
1564                 index = 0;
1565                 goto retry;
1566         }
1567         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
1568                 mapping->writeback_index = index;
1569
1570         FreeXid(xid);
1571         kfree(iov);
1572         return rc;
1573 }
1574
1575 static int cifs_writepage(struct page *page, struct writeback_control *wbc)
1576 {
1577         int rc = -EFAULT;
1578         int xid;
1579
1580         xid = GetXid();
1581 /* BB add check for wbc flags */
1582         page_cache_get(page);
1583         if (!PageUptodate(page))
1584                 cFYI(1, "ppw - page not up to date");
1585
1586         /*
1587          * Set the "writeback" flag, and clear "dirty" in the radix tree.
1588          *
1589          * A writepage() implementation always needs to do either this,
1590          * or re-dirty the page with "redirty_page_for_writepage()" in
1591          * the case of a failure.
1592          *
1593          * Just unlocking the page will cause the radix tree tag-bits
1594          * to fail to update with the state of the page correctly.
1595          */
1596         set_page_writeback(page);
1597         rc = cifs_partialpagewrite(page, 0, PAGE_CACHE_SIZE);
1598         SetPageUptodate(page); /* BB add check for error and Clearuptodate? */
1599         unlock_page(page);
1600         end_page_writeback(page);
1601         page_cache_release(page);
1602         FreeXid(xid);
1603         return rc;
1604 }
1605
1606 static int cifs_write_end(struct file *file, struct address_space *mapping,
1607                         loff_t pos, unsigned len, unsigned copied,
1608                         struct page *page, void *fsdata)
1609 {
1610         int rc;
1611         struct inode *inode = mapping->host;
1612
1613         cFYI(1, "write_end for page %p from pos %lld with %d bytes",
1614                  page, pos, copied);
1615
1616         if (PageChecked(page)) {
1617                 if (copied == len)
1618                         SetPageUptodate(page);
1619                 ClearPageChecked(page);
1620         } else if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE)
1621                 SetPageUptodate(page);
1622
1623         if (!PageUptodate(page)) {
1624                 char *page_data;
1625                 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
1626                 int xid;
1627
1628                 xid = GetXid();
1629                 /* this is probably better than directly calling
1630                    partialpage_write since in this function the file handle is
1631                    known which we might as well leverage */
1632                 /* BB check if anything else missing out of ppw
1633                    such as updating last write time */
1634                 page_data = kmap(page);
1635                 rc = cifs_write(file, page_data + offset, copied, &pos);
1636                 /* if (rc < 0) should we set writebehind rc? */
1637                 kunmap(page);
1638
1639                 FreeXid(xid);
1640         } else {
1641                 rc = copied;
1642                 pos += copied;
1643                 set_page_dirty(page);
1644         }
1645
1646         if (rc > 0) {
1647                 spin_lock(&inode->i_lock);
1648                 if (pos > inode->i_size)
1649                         i_size_write(inode, pos);
1650                 spin_unlock(&inode->i_lock);
1651         }
1652
1653         unlock_page(page);
1654         page_cache_release(page);
1655
1656         return rc;
1657 }
1658
1659 int cifs_fsync(struct file *file, int datasync)
1660 {
1661         int xid;
1662         int rc = 0;
1663         struct cifsTconInfo *tcon;
1664         struct cifsFileInfo *smbfile = file->private_data;
1665         struct inode *inode = file->f_path.dentry->d_inode;
1666
1667         xid = GetXid();
1668
1669         cFYI(1, "Sync file - name: %s datasync: 0x%x",
1670                 file->f_path.dentry->d_name.name, datasync);
1671
1672         rc = filemap_write_and_wait(inode->i_mapping);
1673         if (rc == 0) {
1674                 rc = CIFS_I(inode)->write_behind_rc;
1675                 CIFS_I(inode)->write_behind_rc = 0;
1676                 tcon = tlink_tcon(smbfile->tlink);
1677                 if (!rc && tcon && smbfile &&
1678                    !(CIFS_SB(inode->i_sb)->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC))
1679                         rc = CIFSSMBFlush(xid, tcon, smbfile->netfid);
1680         }
1681
1682         FreeXid(xid);
1683         return rc;
1684 }
1685
1686 /* static void cifs_sync_page(struct page *page)
1687 {
1688         struct address_space *mapping;
1689         struct inode *inode;
1690         unsigned long index = page->index;
1691         unsigned int rpages = 0;
1692         int rc = 0;
1693
1694         cFYI(1, "sync page %p", page);
1695         mapping = page->mapping;
1696         if (!mapping)
1697                 return 0;
1698         inode = mapping->host;
1699         if (!inode)
1700                 return; */
1701
1702 /*      fill in rpages then
1703         result = cifs_pagein_inode(inode, index, rpages); */ /* BB finish */
1704
1705 /*      cFYI(1, "rpages is %d for sync page of Index %ld", rpages, index);
1706
1707 #if 0
1708         if (rc < 0)
1709                 return rc;
1710         return 0;
1711 #endif
1712 } */
1713
1714 /*
1715  * As file closes, flush all cached write data for this inode checking
1716  * for write behind errors.
1717  */
1718 int cifs_flush(struct file *file, fl_owner_t id)
1719 {
1720         struct inode *inode = file->f_path.dentry->d_inode;
1721         int rc = 0;
1722
1723         /* Rather than do the steps manually:
1724            lock the inode for writing
1725            loop through pages looking for write behind data (dirty pages)
1726            coalesce into contiguous 16K (or smaller) chunks to write to server
1727            send to server (prefer in parallel)
1728            deal with writebehind errors
1729            unlock inode for writing
1730            filemapfdatawrite appears easier for the time being */
1731
1732         rc = filemap_fdatawrite(inode->i_mapping);
1733         /* reset wb rc if we were able to write out dirty pages */
1734         if (!rc) {
1735                 rc = CIFS_I(inode)->write_behind_rc;
1736                 CIFS_I(inode)->write_behind_rc = 0;
1737         }
1738
1739         cFYI(1, "Flush inode %p file %p rc %d", inode, file, rc);
1740
1741         return rc;
1742 }
1743
1744 ssize_t cifs_user_read(struct file *file, char __user *read_data,
1745         size_t read_size, loff_t *poffset)
1746 {
1747         int rc = -EACCES;
1748         unsigned int bytes_read = 0;
1749         unsigned int total_read = 0;
1750         unsigned int current_read_size;
1751         struct cifs_sb_info *cifs_sb;
1752         struct cifsTconInfo *pTcon;
1753         int xid;
1754         struct cifsFileInfo *open_file;
1755         char *smb_read_data;
1756         char __user *current_offset;
1757         struct smb_com_read_rsp *pSMBr;
1758
1759         xid = GetXid();
1760         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1761
1762         if (file->private_data == NULL) {
1763                 rc = -EBADF;
1764                 FreeXid(xid);
1765                 return rc;
1766         }
1767         open_file = file->private_data;
1768         pTcon = tlink_tcon(open_file->tlink);
1769
1770         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
1771                 cFYI(1, "attempting read on write only file instance");
1772
1773         for (total_read = 0, current_offset = read_data;
1774              read_size > total_read;
1775              total_read += bytes_read, current_offset += bytes_read) {
1776                 current_read_size = min_t(const int, read_size - total_read,
1777                                           cifs_sb->rsize);
1778                 rc = -EAGAIN;
1779                 smb_read_data = NULL;
1780                 while (rc == -EAGAIN) {
1781                         int buf_type = CIFS_NO_BUFFER;
1782                         if ((open_file->invalidHandle) &&
1783                             (!open_file->closePend)) {
1784                                 rc = cifs_reopen_file(file, true);
1785                                 if (rc != 0)
1786                                         break;
1787                         }
1788                         rc = CIFSSMBRead(xid, pTcon,
1789                                          open_file->netfid,
1790                                          current_read_size, *poffset,
1791                                          &bytes_read, &smb_read_data,
1792                                          &buf_type);
1793                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
1794                         if (smb_read_data) {
1795                                 if (copy_to_user(current_offset,
1796                                                 smb_read_data +
1797                                                 4 /* RFC1001 length field */ +
1798                                                 le16_to_cpu(pSMBr->DataOffset),
1799                                                 bytes_read))
1800                                         rc = -EFAULT;
1801
1802                                 if (buf_type == CIFS_SMALL_BUFFER)
1803                                         cifs_small_buf_release(smb_read_data);
1804                                 else if (buf_type == CIFS_LARGE_BUFFER)
1805                                         cifs_buf_release(smb_read_data);
1806                                 smb_read_data = NULL;
1807                         }
1808                 }
1809                 if (rc || (bytes_read == 0)) {
1810                         if (total_read) {
1811                                 break;
1812                         } else {
1813                                 FreeXid(xid);
1814                                 return rc;
1815                         }
1816                 } else {
1817                         cifs_stats_bytes_read(pTcon, bytes_read);
1818                         *poffset += bytes_read;
1819                 }
1820         }
1821         FreeXid(xid);
1822         return total_read;
1823 }
1824
1825
1826 static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
1827         loff_t *poffset)
1828 {
1829         int rc = -EACCES;
1830         unsigned int bytes_read = 0;
1831         unsigned int total_read;
1832         unsigned int current_read_size;
1833         struct cifs_sb_info *cifs_sb;
1834         struct cifsTconInfo *pTcon;
1835         int xid;
1836         char *current_offset;
1837         struct cifsFileInfo *open_file;
1838         int buf_type = CIFS_NO_BUFFER;
1839
1840         xid = GetXid();
1841         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1842
1843         if (file->private_data == NULL) {
1844                 rc = -EBADF;
1845                 FreeXid(xid);
1846                 return rc;
1847         }
1848         open_file = file->private_data;
1849         pTcon = tlink_tcon(open_file->tlink);
1850
1851         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
1852                 cFYI(1, "attempting read on write only file instance");
1853
1854         for (total_read = 0, current_offset = read_data;
1855              read_size > total_read;
1856              total_read += bytes_read, current_offset += bytes_read) {
1857                 current_read_size = min_t(const int, read_size - total_read,
1858                                           cifs_sb->rsize);
1859                 /* For windows me and 9x we do not want to request more
1860                 than it negotiated since it will refuse the read then */
1861                 if ((pTcon->ses) &&
1862                         !(pTcon->ses->capabilities & CAP_LARGE_FILES)) {
1863                         current_read_size = min_t(const int, current_read_size,
1864                                         pTcon->ses->server->maxBuf - 128);
1865                 }
1866                 rc = -EAGAIN;
1867                 while (rc == -EAGAIN) {
1868                         if ((open_file->invalidHandle) &&
1869                             (!open_file->closePend)) {
1870                                 rc = cifs_reopen_file(file, true);
1871                                 if (rc != 0)
1872                                         break;
1873                         }
1874                         rc = CIFSSMBRead(xid, pTcon,
1875                                          open_file->netfid,
1876                                          current_read_size, *poffset,
1877                                          &bytes_read, &current_offset,
1878                                          &buf_type);
1879                 }
1880                 if (rc || (bytes_read == 0)) {
1881                         if (total_read) {
1882                                 break;
1883                         } else {
1884                                 FreeXid(xid);
1885                                 return rc;
1886                         }
1887                 } else {
1888                         cifs_stats_bytes_read(pTcon, total_read);
1889                         *poffset += bytes_read;
1890                 }
1891         }
1892         FreeXid(xid);
1893         return total_read;
1894 }
1895
1896 int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
1897 {
1898         int rc, xid;
1899
1900         xid = GetXid();
1901         rc = cifs_revalidate_file(file);
1902         if (rc) {
1903                 cFYI(1, "Validation prior to mmap failed, error=%d", rc);
1904                 FreeXid(xid);
1905                 return rc;
1906         }
1907         rc = generic_file_mmap(file, vma);
1908         FreeXid(xid);
1909         return rc;
1910 }
1911
1912
1913 static void cifs_copy_cache_pages(struct address_space *mapping,
1914         struct list_head *pages, int bytes_read, char *data)
1915 {
1916         struct page *page;
1917         char *target;
1918
1919         while (bytes_read > 0) {
1920                 if (list_empty(pages))
1921                         break;
1922
1923                 page = list_entry(pages->prev, struct page, lru);
1924                 list_del(&page->lru);
1925
1926                 if (add_to_page_cache_lru(page, mapping, page->index,
1927                                       GFP_KERNEL)) {
1928                         page_cache_release(page);
1929                         cFYI(1, "Add page cache failed");
1930                         data += PAGE_CACHE_SIZE;
1931                         bytes_read -= PAGE_CACHE_SIZE;
1932                         continue;
1933                 }
1934                 page_cache_release(page);
1935
1936                 target = kmap_atomic(page, KM_USER0);
1937
1938                 if (PAGE_CACHE_SIZE > bytes_read) {
1939                         memcpy(target, data, bytes_read);
1940                         /* zero the tail end of this partial page */
1941                         memset(target + bytes_read, 0,
1942                                PAGE_CACHE_SIZE - bytes_read);
1943                         bytes_read = 0;
1944                 } else {
1945                         memcpy(target, data, PAGE_CACHE_SIZE);
1946                         bytes_read -= PAGE_CACHE_SIZE;
1947                 }
1948                 kunmap_atomic(target, KM_USER0);
1949
1950                 flush_dcache_page(page);
1951                 SetPageUptodate(page);
1952                 unlock_page(page);
1953                 data += PAGE_CACHE_SIZE;
1954
1955                 /* add page to FS-Cache */
1956                 cifs_readpage_to_fscache(mapping->host, page);
1957         }
1958         return;
1959 }
1960
1961 static int cifs_readpages(struct file *file, struct address_space *mapping,
1962         struct list_head *page_list, unsigned num_pages)
1963 {
1964         int rc = -EACCES;
1965         int xid;
1966         loff_t offset;
1967         struct page *page;
1968         struct cifs_sb_info *cifs_sb;
1969         struct cifsTconInfo *pTcon;
1970         unsigned int bytes_read = 0;
1971         unsigned int read_size, i;
1972         char *smb_read_data = NULL;
1973         struct smb_com_read_rsp *pSMBr;
1974         struct cifsFileInfo *open_file;
1975         int buf_type = CIFS_NO_BUFFER;
1976
1977         xid = GetXid();
1978         if (file->private_data == NULL) {
1979                 rc = -EBADF;
1980                 FreeXid(xid);
1981                 return rc;
1982         }
1983         open_file = file->private_data;
1984         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
1985         pTcon = tlink_tcon(open_file->tlink);
1986
1987         /*
1988          * Reads as many pages as possible from fscache. Returns -ENOBUFS
1989          * immediately if the cookie is negative
1990          */
1991         rc = cifs_readpages_from_fscache(mapping->host, mapping, page_list,
1992                                          &num_pages);
1993         if (rc == 0)
1994                 goto read_complete;
1995
1996         cFYI(DBG2, "rpages: num pages %d", num_pages);
1997         for (i = 0; i < num_pages; ) {
1998                 unsigned contig_pages;
1999                 struct page *tmp_page;
2000                 unsigned long expected_index;
2001
2002                 if (list_empty(page_list))
2003                         break;
2004
2005                 page = list_entry(page_list->prev, struct page, lru);
2006                 offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
2007
2008                 /* count adjacent pages that we will read into */
2009                 contig_pages = 0;
2010                 expected_index =
2011                         list_entry(page_list->prev, struct page, lru)->index;
2012                 list_for_each_entry_reverse(tmp_page, page_list, lru) {
2013                         if (tmp_page->index == expected_index) {
2014                                 contig_pages++;
2015                                 expected_index++;
2016                         } else
2017                                 break;
2018                 }
2019                 if (contig_pages + i >  num_pages)
2020                         contig_pages = num_pages - i;
2021
2022                 /* for reads over a certain size could initiate async
2023                    read ahead */
2024
2025                 read_size = contig_pages * PAGE_CACHE_SIZE;
2026                 /* Read size needs to be in multiples of one page */
2027                 read_size = min_t(const unsigned int, read_size,
2028                                   cifs_sb->rsize & PAGE_CACHE_MASK);
2029                 cFYI(DBG2, "rpages: read size 0x%x  contiguous pages %d",
2030                                 read_size, contig_pages);
2031                 rc = -EAGAIN;
2032                 while (rc == -EAGAIN) {
2033                         if ((open_file->invalidHandle) &&
2034                             (!open_file->closePend)) {
2035                                 rc = cifs_reopen_file(file, true);
2036                                 if (rc != 0)
2037                                         break;
2038                         }
2039
2040                         rc = CIFSSMBRead(xid, pTcon,
2041                                          open_file->netfid,
2042                                          read_size, offset,
2043                                          &bytes_read, &smb_read_data,
2044                                          &buf_type);
2045                         /* BB more RC checks ? */
2046                         if (rc == -EAGAIN) {
2047                                 if (smb_read_data) {
2048                                         if (buf_type == CIFS_SMALL_BUFFER)
2049                                                 cifs_small_buf_release(smb_read_data);
2050                                         else if (buf_type == CIFS_LARGE_BUFFER)
2051                                                 cifs_buf_release(smb_read_data);
2052                                         smb_read_data = NULL;
2053                                 }
2054                         }
2055                 }
2056                 if ((rc < 0) || (smb_read_data == NULL)) {
2057                         cFYI(1, "Read error in readpages: %d", rc);
2058                         break;
2059                 } else if (bytes_read > 0) {
2060                         task_io_account_read(bytes_read);
2061                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
2062                         cifs_copy_cache_pages(mapping, page_list, bytes_read,
2063                                 smb_read_data + 4 /* RFC1001 hdr */ +
2064                                 le16_to_cpu(pSMBr->DataOffset));
2065
2066                         i +=  bytes_read >> PAGE_CACHE_SHIFT;
2067                         cifs_stats_bytes_read(pTcon, bytes_read);
2068                         if ((bytes_read & PAGE_CACHE_MASK) != bytes_read) {
2069                                 i++; /* account for partial page */
2070
2071                                 /* server copy of file can have smaller size
2072                                    than client */
2073                                 /* BB do we need to verify this common case ?
2074                                    this case is ok - if we are at server EOF
2075                                    we will hit it on next read */
2076
2077                                 /* break; */
2078                         }
2079                 } else {
2080                         cFYI(1, "No bytes read (%d) at offset %lld . "
2081                                 "Cleaning remaining pages from readahead list",
2082                                 bytes_read, offset);
2083                         /* BB turn off caching and do new lookup on
2084                            file size at server? */
2085                         break;
2086                 }
2087                 if (smb_read_data) {
2088                         if (buf_type == CIFS_SMALL_BUFFER)
2089                                 cifs_small_buf_release(smb_read_data);
2090                         else if (buf_type == CIFS_LARGE_BUFFER)
2091                                 cifs_buf_release(smb_read_data);
2092                         smb_read_data = NULL;
2093                 }
2094                 bytes_read = 0;
2095         }
2096
2097 /* need to free smb_read_data buf before exit */
2098         if (smb_read_data) {
2099                 if (buf_type == CIFS_SMALL_BUFFER)
2100                         cifs_small_buf_release(smb_read_data);
2101                 else if (buf_type == CIFS_LARGE_BUFFER)
2102                         cifs_buf_release(smb_read_data);
2103                 smb_read_data = NULL;
2104         }
2105
2106 read_complete:
2107         FreeXid(xid);
2108         return rc;
2109 }
2110
2111 static int cifs_readpage_worker(struct file *file, struct page *page,
2112         loff_t *poffset)
2113 {
2114         char *read_data;
2115         int rc;
2116
2117         /* Is the page cached? */
2118         rc = cifs_readpage_from_fscache(file->f_path.dentry->d_inode, page);
2119         if (rc == 0)
2120                 goto read_complete;
2121
2122         page_cache_get(page);
2123         read_data = kmap(page);
2124         /* for reads over a certain size could initiate async read ahead */
2125
2126         rc = cifs_read(file, read_data, PAGE_CACHE_SIZE, poffset);
2127
2128         if (rc < 0)
2129                 goto io_error;
2130         else
2131                 cFYI(1, "Bytes read %d", rc);
2132
2133         file->f_path.dentry->d_inode->i_atime =
2134                 current_fs_time(file->f_path.dentry->d_inode->i_sb);
2135
2136         if (PAGE_CACHE_SIZE > rc)
2137                 memset(read_data + rc, 0, PAGE_CACHE_SIZE - rc);
2138
2139         flush_dcache_page(page);
2140         SetPageUptodate(page);
2141
2142         /* send this page to the cache */
2143         cifs_readpage_to_fscache(file->f_path.dentry->d_inode, page);
2144
2145         rc = 0;
2146
2147 io_error:
2148         kunmap(page);
2149         page_cache_release(page);
2150
2151 read_complete:
2152         return rc;
2153 }
2154
2155 static int cifs_readpage(struct file *file, struct page *page)
2156 {
2157         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
2158         int rc = -EACCES;
2159         int xid;
2160
2161         xid = GetXid();
2162
2163         if (file->private_data == NULL) {
2164                 rc = -EBADF;
2165                 FreeXid(xid);
2166                 return rc;
2167         }
2168
2169         cFYI(1, "readpage %p at offset %d 0x%x\n",
2170                  page, (int)offset, (int)offset);
2171
2172         rc = cifs_readpage_worker(file, page, &offset);
2173
2174         unlock_page(page);
2175
2176         FreeXid(xid);
2177         return rc;
2178 }
2179
2180 static int is_inode_writable(struct cifsInodeInfo *cifs_inode)
2181 {
2182         struct cifsFileInfo *open_file;
2183
2184         read_lock(&GlobalSMBSeslock);
2185         list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
2186                 if (open_file->closePend)
2187                         continue;
2188                 if (open_file->pfile &&
2189                     ((open_file->pfile->f_flags & O_RDWR) ||
2190                      (open_file->pfile->f_flags & O_WRONLY))) {
2191                         read_unlock(&GlobalSMBSeslock);
2192                         return 1;
2193                 }
2194         }
2195         read_unlock(&GlobalSMBSeslock);
2196         return 0;
2197 }
2198
2199 /* We do not want to update the file size from server for inodes
2200    open for write - to avoid races with writepage extending
2201    the file - in the future we could consider allowing
2202    refreshing the inode only on increases in the file size
2203    but this is tricky to do without racing with writebehind
2204    page caching in the current Linux kernel design */
2205 bool is_size_safe_to_change(struct cifsInodeInfo *cifsInode, __u64 end_of_file)
2206 {
2207         if (!cifsInode)
2208                 return true;
2209
2210         if (is_inode_writable(cifsInode)) {
2211                 /* This inode is open for write at least once */
2212                 struct cifs_sb_info *cifs_sb;
2213
2214                 cifs_sb = CIFS_SB(cifsInode->vfs_inode.i_sb);
2215                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO) {
2216                         /* since no page cache to corrupt on directio
2217                         we can change size safely */
2218                         return true;
2219                 }
2220
2221                 if (i_size_read(&cifsInode->vfs_inode) < end_of_file)
2222                         return true;
2223
2224                 return false;
2225         } else
2226                 return true;
2227 }
2228
2229 static int cifs_write_begin(struct file *file, struct address_space *mapping,
2230                         loff_t pos, unsigned len, unsigned flags,
2231                         struct page **pagep, void **fsdata)
2232 {
2233         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
2234         loff_t offset = pos & (PAGE_CACHE_SIZE - 1);
2235         loff_t page_start = pos & PAGE_MASK;
2236         loff_t i_size;
2237         struct page *page;
2238         int rc = 0;
2239
2240         cFYI(1, "write_begin from %lld len %d", (long long)pos, len);
2241
2242         page = grab_cache_page_write_begin(mapping, index, flags);
2243         if (!page) {
2244                 rc = -ENOMEM;
2245                 goto out;
2246         }
2247
2248         if (PageUptodate(page))
2249                 goto out;
2250
2251         /*
2252          * If we write a full page it will be up to date, no need to read from
2253          * the server. If the write is short, we'll end up doing a sync write
2254          * instead.
2255          */
2256         if (len == PAGE_CACHE_SIZE)
2257                 goto out;
2258
2259         /*
2260          * optimize away the read when we have an oplock, and we're not
2261          * expecting to use any of the data we'd be reading in. That
2262          * is, when the page lies beyond the EOF, or straddles the EOF
2263          * and the write will cover all of the existing data.
2264          */
2265         if (CIFS_I(mapping->host)->clientCanCacheRead) {
2266                 i_size = i_size_read(mapping->host);
2267                 if (page_start >= i_size ||
2268                     (offset == 0 && (pos + len) >= i_size)) {
2269                         zero_user_segments(page, 0, offset,
2270                                            offset + len,
2271                                            PAGE_CACHE_SIZE);
2272                         /*
2273                          * PageChecked means that the parts of the page
2274                          * to which we're not writing are considered up
2275                          * to date. Once the data is copied to the
2276                          * page, it can be set uptodate.
2277                          */
2278                         SetPageChecked(page);
2279                         goto out;
2280                 }
2281         }
2282
2283         if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
2284                 /*
2285                  * might as well read a page, it is fast enough. If we get
2286                  * an error, we don't need to return it. cifs_write_end will
2287                  * do a sync write instead since PG_uptodate isn't set.
2288                  */
2289                 cifs_readpage_worker(file, page, &page_start);
2290         } else {
2291                 /* we could try using another file handle if there is one -
2292                    but how would we lock it to prevent close of that handle
2293                    racing with this read? In any case
2294                    this will be written out by write_end so is fine */
2295         }
2296 out:
2297         *pagep = page;
2298         return rc;
2299 }
2300
2301 static int cifs_release_page(struct page *page, gfp_t gfp)
2302 {
2303         if (PagePrivate(page))
2304                 return 0;
2305
2306         return cifs_fscache_release_page(page, gfp);
2307 }
2308
2309 static void cifs_invalidate_page(struct page *page, unsigned long offset)
2310 {
2311         struct cifsInodeInfo *cifsi = CIFS_I(page->mapping->host);
2312
2313         if (offset == 0)
2314                 cifs_fscache_invalidate_page(page, &cifsi->vfs_inode);
2315 }
2316
2317 void cifs_oplock_break(struct work_struct *work)
2318 {
2319         struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
2320                                                   oplock_break);
2321         struct inode *inode = cfile->pInode;
2322         struct cifsInodeInfo *cinode = CIFS_I(inode);
2323         int rc, waitrc = 0;
2324
2325         if (inode && S_ISREG(inode->i_mode)) {
2326                 if (cinode->clientCanCacheRead)
2327                         break_lease(inode, O_RDONLY);
2328                 else
2329                         break_lease(inode, O_WRONLY);
2330                 rc = filemap_fdatawrite(inode->i_mapping);
2331                 if (cinode->clientCanCacheRead == 0) {
2332                         waitrc = filemap_fdatawait(inode->i_mapping);
2333                         invalidate_remote_inode(inode);
2334                 }
2335                 if (!rc)
2336                         rc = waitrc;
2337                 if (rc)
2338                         cinode->write_behind_rc = rc;
2339                 cFYI(1, "Oplock flush inode %p rc %d", inode, rc);
2340         }
2341
2342         /*
2343          * releasing stale oplock after recent reconnect of smb session using
2344          * a now incorrect file handle is not a data integrity issue but do
2345          * not bother sending an oplock release if session to server still is
2346          * disconnected since oplock already released by the server
2347          */
2348         if (!cfile->closePend && !cfile->oplock_break_cancelled) {
2349                 rc = CIFSSMBLock(0, tlink_tcon(cfile->tlink), cfile->netfid, 0,
2350                                  0, 0, 0, LOCKING_ANDX_OPLOCK_RELEASE, false);
2351                 cFYI(1, "Oplock release rc = %d", rc);
2352         }
2353
2354         /*
2355          * We might have kicked in before is_valid_oplock_break()
2356          * finished grabbing reference for us.  Make sure it's done by
2357          * waiting for GlobalSMSSeslock.
2358          */
2359         write_lock(&GlobalSMBSeslock);
2360         write_unlock(&GlobalSMBSeslock);
2361
2362         cifs_oplock_break_put(cfile);
2363 }
2364
2365 void cifs_oplock_break_get(struct cifsFileInfo *cfile)
2366 {
2367         mntget(cfile->mnt);
2368         cifsFileInfo_get(cfile);
2369 }
2370
2371 void cifs_oplock_break_put(struct cifsFileInfo *cfile)
2372 {
2373         mntput(cfile->mnt);
2374         cifsFileInfo_put(cfile);
2375 }
2376
2377 const struct address_space_operations cifs_addr_ops = {
2378         .readpage = cifs_readpage,
2379         .readpages = cifs_readpages,
2380         .writepage = cifs_writepage,
2381         .writepages = cifs_writepages,
2382         .write_begin = cifs_write_begin,
2383         .write_end = cifs_write_end,
2384         .set_page_dirty = __set_page_dirty_nobuffers,
2385         .releasepage = cifs_release_page,
2386         .invalidatepage = cifs_invalidate_page,
2387         /* .sync_page = cifs_sync_page, */
2388         /* .direct_IO = */
2389 };
2390
2391 /*
2392  * cifs_readpages requires the server to support a buffer large enough to
2393  * contain the header plus one complete page of data.  Otherwise, we need
2394  * to leave cifs_readpages out of the address space operations.
2395  */
2396 const struct address_space_operations cifs_addr_ops_smallbuf = {
2397         .readpage = cifs_readpage,
2398         .writepage = cifs_writepage,
2399         .writepages = cifs_writepages,
2400         .write_begin = cifs_write_begin,
2401         .write_end = cifs_write_end,
2402         .set_page_dirty = __set_page_dirty_nobuffers,
2403         .releasepage = cifs_release_page,
2404         .invalidatepage = cifs_invalidate_page,
2405         /* .sync_page = cifs_sync_page, */
2406         /* .direct_IO = */
2407 };