fs/9p/vfs_file.c

   1 /*
   2  *  linux/fs/9p/vfs_file.c
   3  *
   4  * This file contians vfs file ops for 9P2000.
   5  *
   6  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2
  11  *  as published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to:
  20  *  Free Software Foundation
  21  *  51 Franklin Street, Fifth Floor
  22  *  Boston, MA  02111-1301  USA
  23  *
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/fs.h>
  29 #include <linux/sched.h>
  30 #include <linux/file.h>
  31 #include <linux/stat.h>
  32 #include <linux/string.h>
  33 #include <linux/inet.h>
  34 #include <linux/list.h>
  35 #include <linux/pagemap.h>
  36 #include <linux/utsname.h>
  37 #include <asm/uaccess.h>
  38 #include <linux/idr.h>
  39 #include <net/9p/9p.h>
  40 #include <net/9p/client.h>
  41
  42 #include "v9fs.h"
  43 #include "v9fs_vfs.h"
  44 #include "fid.h"
  45 #include "cache.h"
  46
  47 static const struct vm_operations_struct v9fs_file_vm_ops;
  48
  49 /**
  50  * v9fs_file_open - open a file (or directory)
  51  * @inode: inode to be opened
  52  * @file: file being opened
  53  *
  54  */
  55
  56 int v9fs_file_open(struct inode *inode, struct file *file)
  57 {
  58         int err;
  59         struct v9fs_inode *v9inode;
  60         struct v9fs_session_info *v9ses;
  61         struct p9_fid *fid;
  62         int omode;
  63
  64         P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
  65         v9inode = V9FS_I(inode);
  66         v9ses = v9fs_inode2v9ses(inode);
  67         if (v9fs_proto_dotl(v9ses))
  68                 omode = v9fs_open_to_dotl_flags(file->f_flags);
  69         else
  70                 omode = v9fs_uflags2omode(file->f_flags,
  71                                         v9fs_proto_dotu(v9ses));
  72         fid = file->private_data;
  73         if (!fid) {
  74                 fid = v9fs_fid_clone(file->f_path.dentry);
  75                 if (IS_ERR(fid))
  76                         return PTR_ERR(fid);
  77
  78                 err = p9_client_open(fid, omode);
  79                 if (err < 0) {
  80                         p9_client_clunk(fid);
  81                         return err;
  82                 }
  83                 if (file->f_flags & O_TRUNC) {
  84                         i_size_write(inode, 0);
  85                         inode->i_blocks = 0;
  86                 }
  87                 if ((file->f_flags & O_APPEND) &&
  88                         (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
  89                         generic_file_llseek(file, 0, SEEK_END);
  90         }
  91
  92         file->private_data = fid;
  93         mutex_lock(&v9inode->v_mutex);
  94         if (v9ses->cache && !v9inode->writeback_fid &&
  95             ((file->f_flags & O_ACCMODE) != O_RDONLY)) {
  96                 /*
  97                  * clone a fid and add it to writeback_fid
  98                  * we do it during open time instead of
  99                  * page dirty time via write_begin/page_mkwrite
 100                  * because we want write after unlink usecase
 101                  * to work.
 102                  */
 103                 fid = v9fs_writeback_fid(file->f_path.dentry);
 104                 if (IS_ERR(fid)) {
 105                         err = PTR_ERR(fid);
 106                         mutex_unlock(&v9inode->v_mutex);
 107                         goto out_error;
 108                 }
 109                 v9inode->writeback_fid = (void *) fid;
 110         }
 111         mutex_unlock(&v9inode->v_mutex);
 112 #ifdef CONFIG_9P_FSCACHE
 113         if (v9ses->cache)
 114                 v9fs_cache_inode_set_cookie(inode, file);
 115 #endif
 116         return 0;
 117 out_error:
 118         p9_client_clunk(file->private_data);
 119         file->private_data = NULL;
 120         return err;
 121 }
 122
 123 /**
 124  * v9fs_file_lock - lock a file (or directory)
 125  * @filp: file to be locked
 126  * @cmd: lock command
 127  * @fl: file lock structure
 128  *
 129  * Bugs: this looks like a local only lock, we should extend into 9P
 130  *       by using open exclusive
 131  */
 132
 133 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 134 {
 135         int res = 0;
 136         struct inode *inode = filp->f_path.dentry->d_inode;
 137
 138         P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 139
 140         /* No mandatory locks */
 141         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 142                 return -ENOLCK;
 143
 144         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 145                 filemap_write_and_wait(inode->i_mapping);
 146                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 147         }
 148
 149         return res;
 150 }
 151
 152 static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
 153 {
 154         struct p9_flock flock;
 155         struct p9_fid *fid;
 156         uint8_t status;
 157         int res = 0;
 158         unsigned char fl_type;
 159
 160         fid = filp->private_data;
 161         BUG_ON(fid == NULL);
 162
 163         if ((fl->fl_flags & FL_POSIX) != FL_POSIX)
 164                 BUG();
 165
 166         res = posix_lock_file_wait(filp, fl);
 167         if (res < 0)
 168                 goto out;
 169
 170         /* convert posix lock to p9 tlock args */
 171         memset(&flock, 0, sizeof(flock));
 172         /* map the lock type */
 173         switch (fl->fl_type) {
 174         case F_RDLCK:
 175                 flock.type = P9_LOCK_TYPE_RDLCK;
 176                 break;
 177         case F_WRLCK:
 178                 flock.type = P9_LOCK_TYPE_WRLCK;
 179                 break;
 180         case F_UNLCK:
 181                 flock.type = P9_LOCK_TYPE_UNLCK;
 182                 break;
 183         }
 184         flock.start = fl->fl_start;
 185         if (fl->fl_end == OFFSET_MAX)
 186                 flock.length = 0;
 187         else
 188                 flock.length = fl->fl_end - fl->fl_start + 1;
 189         flock.proc_id = fl->fl_pid;
 190         flock.client_id = utsname()->nodename;
 191         if (IS_SETLKW(cmd))
 192                 flock.flags = P9_LOCK_FLAGS_BLOCK;
 193
 194         /*
 195          * if its a blocked request and we get P9_LOCK_BLOCKED as the status
 196          * for lock request, keep on trying
 197          */
 198         for (;;) {
 199                 res = p9_client_lock_dotl(fid, &flock, &status);
 200                 if (res < 0)
 201                         break;
 202
 203                 if (status != P9_LOCK_BLOCKED)
 204                         break;
 205                 if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
 206                         break;
 207                 schedule_timeout_interruptible(P9_LOCK_TIMEOUT);
 208         }
 209
 210         /* map 9p status to VFS status */
 211         switch (status) {
 212         case P9_LOCK_SUCCESS:
 213                 res = 0;
 214                 break;
 215         case P9_LOCK_BLOCKED:
 216                 res = -EAGAIN;
 217                 break;
 218         case P9_LOCK_ERROR:
 219         case P9_LOCK_GRACE:
 220                 res = -ENOLCK;
 221                 break;
 222         default:
 223                 BUG();
 224         }
 225
 226         /*
 227          * incase server returned error for lock request, revert
 228          * it locally
 229          */
 230         if (res < 0 && fl->fl_type != F_UNLCK) {
 231                 fl_type = fl->fl_type;
 232                 fl->fl_type = F_UNLCK;
 233                 res = posix_lock_file_wait(filp, fl);
 234                 fl->fl_type = fl_type;
 235         }
 236 out:
 237         return res;
 238 }
 239
 240 static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
 241 {
 242         struct p9_getlock glock;
 243         struct p9_fid *fid;
 244         int res = 0;
 245
 246         fid = filp->private_data;
 247         BUG_ON(fid == NULL);
 248
 249         posix_test_lock(filp, fl);
 250         /*
 251          * if we have a conflicting lock locally, no need to validate
 252          * with server
 253          */
 254         if (fl->fl_type != F_UNLCK)
 255                 return res;
 256
 257         /* convert posix lock to p9 tgetlock args */
 258         memset(&glock, 0, sizeof(glock));
 259         glock.type  = P9_LOCK_TYPE_UNLCK;
 260         glock.start = fl->fl_start;
 261         if (fl->fl_end == OFFSET_MAX)
 262                 glock.length = 0;
 263         else
 264                 glock.length = fl->fl_end - fl->fl_start + 1;
 265         glock.proc_id = fl->fl_pid;
 266         glock.client_id = utsname()->nodename;
 267
 268         res = p9_client_getlock_dotl(fid, &glock);
 269         if (res < 0)
 270                 return res;
 271         /* map 9p lock type to os lock type */
 272         switch (glock.type) {
 273         case P9_LOCK_TYPE_RDLCK:
 274                 fl->fl_type = F_RDLCK;
 275                 break;
 276         case P9_LOCK_TYPE_WRLCK:
 277                 fl->fl_type = F_WRLCK;
 278                 break;
 279         case P9_LOCK_TYPE_UNLCK:
 280                 fl->fl_type = F_UNLCK;
 281                 break;
 282         }
 283         if (glock.type != P9_LOCK_TYPE_UNLCK) {
 284                 fl->fl_start = glock.start;
 285                 if (glock.length == 0)
 286                         fl->fl_end = OFFSET_MAX;
 287                 else
 288                         fl->fl_end = glock.start + glock.length - 1;
 289                 fl->fl_pid = glock.proc_id;
 290         }
 291         return res;
 292 }
 293
 294 /**
 295  * v9fs_file_lock_dotl - lock a file (or directory)
 296  * @filp: file to be locked
 297  * @cmd: lock command
 298  * @fl: file lock structure
 299  *
 300  */
 301
 302 static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
 303 {
 304         struct inode *inode = filp->f_path.dentry->d_inode;
 305         int ret = -ENOLCK;
 306
 307         P9_DPRINTK(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n", filp,
 308                                 cmd, fl, filp->f_path.dentry->d_name.name);
 309
 310         /* No mandatory locks */
 311         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 312                 goto out_err;
 313
 314         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 315                 filemap_write_and_wait(inode->i_mapping);
 316                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 317         }
 318
 319         if (IS_SETLK(cmd) || IS_SETLKW(cmd))
 320                 ret = v9fs_file_do_lock(filp, cmd, fl);
 321         else if (IS_GETLK(cmd))
 322                 ret = v9fs_file_getlock(filp, fl);
 323         else
 324                 ret = -EINVAL;
 325 out_err:
 326         return ret;
 327 }
 328
 329 /**
 330  * v9fs_file_flock_dotl - lock a file
 331  * @filp: file to be locked
 332  * @cmd: lock command
 333  * @fl: file lock structure
 334  *
 335  */
 336
 337 static int v9fs_file_flock_dotl(struct file *filp, int cmd,
 338         struct file_lock *fl)
 339 {
 340         struct inode *inode = filp->f_path.dentry->d_inode;
 341         int ret = -ENOLCK;
 342
 343         P9_DPRINTK(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n", filp,
 344                                 cmd, fl, filp->f_path.dentry->d_name.name);
 345
 346         /* No mandatory locks */
 347         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 348                 goto out_err;
 349
 350         if (!(fl->fl_flags & FL_FLOCK))
 351                 goto out_err;
 352
 353         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 354                 filemap_write_and_wait(inode->i_mapping);
 355                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 356         }
 357         /* Convert flock to posix lock */
 358         fl->fl_owner = (fl_owner_t)filp;
 359         fl->fl_start = 0;
 360         fl->fl_end = OFFSET_MAX;
 361         fl->fl_flags |= FL_POSIX;
 362         fl->fl_flags ^= FL_FLOCK;
 363
 364         if (IS_SETLK(cmd) | IS_SETLKW(cmd))
 365                 ret = v9fs_file_do_lock(filp, cmd, fl);
 366         else
 367                 ret = -EINVAL;
 368 out_err:
 369         return ret;
 370 }
 371
 372 /**
 373  * v9fs_fid_readn - read from a fid
 374  * @fid: fid to read
 375  * @data: data buffer to read data into
 376  * @udata: user data buffer to read data into
 377  * @count: size of buffer
 378  * @offset: offset at which to read data
 379  *
 380  */
 381 ssize_t
 382 v9fs_fid_readn(struct p9_fid *fid, char *data, char __user *udata, u32 count,
 383                u64 offset)
 384 {
 385         int n, total, size;
 386
 387         P9_DPRINTK(P9_DEBUG_VFS, "fid %d offset %llu count %d\n", fid->fid,
 388                    (long long unsigned) offset, count);
 389         n = 0;
 390         total = 0;
 391         size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
 392         do {
 393                 n = p9_client_read(fid, data, udata, offset, count);
 394                 if (n <= 0)
 395                         break;
 396
 397                 if (data)
 398                         data += n;
 399                 if (udata)
 400                         udata += n;
 401
 402                 offset += n;
 403                 count -= n;
 404                 total += n;
 405         } while (count > 0 && n == size);
 406
 407         if (n < 0)
 408                 total = n;
 409
 410         return total;
 411 }
 412
 413 /**
 414  * v9fs_file_readn - read from a file
 415  * @filp: file pointer to read
 416  * @data: data buffer to read data into
 417  * @udata: user data buffer to read data into
 418  * @count: size of buffer
 419  * @offset: offset at which to read data
 420  *
 421  */
 422 ssize_t
 423 v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
 424                u64 offset)
 425 {
 426         return v9fs_fid_readn(filp->private_data, data, udata, count, offset);
 427 }
 428
 429 /**
 430  * v9fs_file_read - read from a file
 431  * @filp: file pointer to read
 432  * @udata: user data buffer to read data into
 433  * @count: size of buffer
 434  * @offset: offset at which to read data
 435  *
 436  */
 437
 438 static ssize_t
 439 v9fs_file_read(struct file *filp, char __user *udata, size_t count,
 440                loff_t * offset)
 441 {
 442         int ret;
 443         struct p9_fid *fid;
 444         size_t size;
 445
 446         P9_DPRINTK(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset);
 447         fid = filp->private_data;
 448
 449         size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
 450         if (count > size)
 451                 ret = v9fs_file_readn(filp, NULL, udata, count, *offset);
 452         else
 453                 ret = p9_client_read(fid, NULL, udata, *offset, count);
 454
 455         if (ret > 0)
 456                 *offset += ret;
 457
 458         return ret;
 459 }
 460
 461 ssize_t
 462 v9fs_file_write_internal(struct inode *inode, struct p9_fid *fid,
 463                          const char __user *data, size_t count,
 464                          loff_t *offset, int invalidate)
 465 {
 466         int n;
 467         loff_t i_size;
 468         size_t total = 0;
 469         struct p9_client *clnt;
 470         loff_t origin = *offset;
 471         unsigned long pg_start, pg_end;
 472
 473         P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data,
 474                 (int)count, (int)*offset);
 475
 476         clnt = fid->clnt;
 477         do {
 478                 n = p9_client_write(fid, NULL, data+total, origin+total, count);
 479                 if (n <= 0)
 480                         break;
 481                 count -= n;
 482                 total += n;
 483         } while (count > 0);
 484
 485         if (invalidate && (total > 0)) {
 486                 pg_start = origin >> PAGE_CACHE_SHIFT;
 487                 pg_end = (origin + total - 1) >> PAGE_CACHE_SHIFT;
 488                 if (inode->i_mapping && inode->i_mapping->nrpages)
 489                         invalidate_inode_pages2_range(inode->i_mapping,
 490                                                       pg_start, pg_end);
 491                 *offset += total;
 492                 i_size = i_size_read(inode);
 493                 if (*offset > i_size) {
 494                         inode_add_bytes(inode, *offset - i_size);
 495                         i_size_write(inode, *offset);
 496                 }
 497         }
 498         if (n < 0)
 499                 return n;
 500
 501         return total;
 502 }
 503
 504 /**
 505  * v9fs_file_write - write to a file
 506  * @filp: file pointer to write
 507  * @data: data buffer to write data from
 508  * @count: size of buffer
 509  * @offset: offset at which to write data
 510  *
 511  */
 512 static ssize_t
 513 v9fs_file_write(struct file *filp, const char __user * data,
 514                 size_t count, loff_t *offset)
 515 {
 516         ssize_t retval = 0;
 517         loff_t origin = *offset;
 518
 519
 520         retval = generic_write_checks(filp, &origin, &count, 0);
 521         if (retval)
 522                 goto out;
 523
 524         retval = -EINVAL;
 525         if ((ssize_t) count < 0)
 526                 goto out;
 527         retval = 0;
 528         if (!count)
 529                 goto out;
 530
 531         retval = v9fs_file_write_internal(filp->f_path.dentry->d_inode,
 532                                         filp->private_data,
 533                                         data, count, &origin, 1);
 534         /* update offset on successful write */
 535         if (retval > 0)
 536                 *offset = origin;
 537 out:
 538         return retval;
 539 }
 540
 541
 542 static int v9fs_file_fsync(struct file *filp, int datasync)
 543 {
 544         struct p9_fid *fid;
 545         struct p9_wstat wstat;
 546         int retval;
 547
 548         P9_DPRINTK(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
 549
 550         fid = filp->private_data;
 551         v9fs_blank_wstat(&wstat);
 552
 553         retval = p9_client_wstat(fid, &wstat);
 554         return retval;
 555 }
 556
 557 int v9fs_file_fsync_dotl(struct file *filp, int datasync)
 558 {
 559         struct p9_fid *fid;
 560         int retval;
 561
 562         P9_DPRINTK(P9_DEBUG_VFS, "v9fs_file_fsync_dotl: filp %p datasync %x\n",
 563                         filp, datasync);
 564
 565         fid = filp->private_data;
 566
 567         retval = p9_client_fsync(fid, datasync);
 568         return retval;
 569 }
 570
 571 static int
 572 v9fs_file_mmap(struct file *file, struct vm_area_struct *vma)
 573 {
 574         int retval;
 575
 576         retval = generic_file_mmap(file, vma);
 577         if (!retval)
 578                 vma->vm_ops = &v9fs_file_vm_ops;
 579
 580         return retval;
 581 }
 582
 583 static int
 584 v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 585 {
 586         struct v9fs_inode *v9inode;
 587         struct page *page = vmf->page;
 588         struct file *filp = vma->vm_file;
 589         struct inode *inode = filp->f_path.dentry->d_inode;
 590
 591
 592         P9_DPRINTK(P9_DEBUG_VFS, "page %p fid %lx\n",
 593                    page, (unsigned long)filp->private_data);
 594
 595         v9inode = V9FS_I(inode);
 596         /* make sure the cache has finished storing the page */
 597         v9fs_fscache_wait_on_page_write(inode, page);
 598         BUG_ON(!v9inode->writeback_fid);
 599         lock_page(page);
 600         if (page->mapping != inode->i_mapping)
 601                 goto out_unlock;
 602
 603         return VM_FAULT_LOCKED;
 604 out_unlock:
 605         unlock_page(page);
 606         return VM_FAULT_NOPAGE;
 607 }
 608
 609 static ssize_t
 610 v9fs_direct_read(struct file *filp, char __user *udata, size_t count,
 611                  loff_t *offsetp)
 612 {
 613         loff_t size, offset;
 614         struct inode *inode;
 615         struct address_space *mapping;
 616
 617         offset = *offsetp;
 618         mapping = filp->f_mapping;
 619         inode = mapping->host;
 620         if (!count)
 621                 return 0;
 622         size = i_size_read(inode);
 623         if (offset < size)
 624                 filemap_write_and_wait_range(mapping, offset,
 625                                              offset + count - 1);
 626
 627         return v9fs_file_read(filp, udata, count, offsetp);
 628 }
 629
 630 /**
 631  * v9fs_cached_file_read - read from a file
 632  * @filp: file pointer to read
 633  * @udata: user data buffer to read data into
 634  * @count: size of buffer
 635  * @offset: offset at which to read data
 636  *
 637  */
 638 static ssize_t
 639 v9fs_cached_file_read(struct file *filp, char __user *data, size_t count,
 640                       loff_t *offset)
 641 {
 642         if (filp->f_flags & O_DIRECT)
 643                 return v9fs_direct_read(filp, data, count, offset);
 644         return do_sync_read(filp, data, count, offset);
 645 }
 646
 647 static ssize_t
 648 v9fs_direct_write(struct file *filp, const char __user * data,
 649                   size_t count, loff_t *offsetp)
 650 {
 651         loff_t offset;
 652         ssize_t retval;
 653         struct inode *inode;
 654         struct address_space *mapping;
 655
 656         offset = *offsetp;
 657         mapping = filp->f_mapping;
 658         inode = mapping->host;
 659         if (!count)
 660                 return 0;
 661
 662         mutex_lock(&inode->i_mutex);
 663         retval = filemap_write_and_wait_range(mapping, offset,
 664                                               offset + count - 1);
 665         if (retval)
 666                 goto err_out;
 667         /*
 668          * After a write we want buffered reads to be sure to go to disk to get
 669          * the new data.  We invalidate clean cached page from the region we're
 670          * about to write.  We do this *before* the write so that if we fail
 671          * here we fall back to buffered write
 672          */
 673         if (mapping->nrpages) {
 674                 pgoff_t pg_start = offset >> PAGE_CACHE_SHIFT;
 675                 pgoff_t pg_end   = (offset + count - 1) >> PAGE_CACHE_SHIFT;
 676
 677                 retval = invalidate_inode_pages2_range(mapping,
 678                                                         pg_start, pg_end);
 679                 /*
 680                  * If a page can not be invalidated, fall back
 681                  * to buffered write.
 682                  */
 683                 if (retval) {
 684                         if (retval == -EBUSY)
 685                                 goto buff_write;
 686                         goto err_out;
 687                 }
 688         }
 689         retval = v9fs_file_write(filp, data, count, offsetp);
 690 err_out:
 691         mutex_unlock(&inode->i_mutex);
 692         return retval;
 693
 694 buff_write:
 695         mutex_unlock(&inode->i_mutex);
 696         return do_sync_write(filp, data, count, offsetp);
 697 }
 698
 699 /**
 700  * v9fs_cached_file_write - write to a file
 701  * @filp: file pointer to write
 702  * @data: data buffer to write data from
 703  * @count: size of buffer
 704  * @offset: offset at which to write data
 705  *
 706  */
 707 static ssize_t
 708 v9fs_cached_file_write(struct file *filp, const char __user * data,
 709                        size_t count, loff_t *offset)
 710 {
 711
 712         if (filp->f_flags & O_DIRECT)
 713                 return v9fs_direct_write(filp, data, count, offset);
 714         return do_sync_write(filp, data, count, offset);
 715 }
 716
 717 static const struct vm_operations_struct v9fs_file_vm_ops = {
 718         .fault = filemap_fault,
 719         .page_mkwrite = v9fs_vm_page_mkwrite,
 720 };
 721
 722
 723 const struct file_operations v9fs_cached_file_operations = {
 724         .llseek = generic_file_llseek,
 725         .read = v9fs_cached_file_read,
 726         .write = v9fs_cached_file_write,
 727         .aio_read = generic_file_aio_read,
 728         .aio_write = generic_file_aio_write,
 729         .open = v9fs_file_open,
 730         .release = v9fs_dir_release,
 731         .lock = v9fs_file_lock,
 732         .mmap = v9fs_file_mmap,
 733         .fsync = v9fs_file_fsync,
 734 };
 735
 736 const struct file_operations v9fs_cached_file_operations_dotl = {
 737         .llseek = generic_file_llseek,
 738         .read = v9fs_cached_file_read,
 739         .write = v9fs_cached_file_write,
 740         .aio_read = generic_file_aio_read,
 741         .aio_write = generic_file_aio_write,
 742         .open = v9fs_file_open,
 743         .release = v9fs_dir_release,
 744         .lock = v9fs_file_lock_dotl,
 745         .flock = v9fs_file_flock_dotl,
 746         .mmap = v9fs_file_mmap,
 747         .fsync = v9fs_file_fsync_dotl,
 748 };
 749
 750 const struct file_operations v9fs_file_operations = {
 751         .llseek = generic_file_llseek,
 752         .read = v9fs_file_read,
 753         .write = v9fs_file_write,
 754         .open = v9fs_file_open,
 755         .release = v9fs_dir_release,
 756         .lock = v9fs_file_lock,
 757         .mmap = generic_file_readonly_mmap,
 758         .fsync = v9fs_file_fsync,
 759 };
 760
 761 const struct file_operations v9fs_file_operations_dotl = {
 762         .llseek = generic_file_llseek,
 763         .read = v9fs_file_read,
 764         .write = v9fs_file_write,
 765         .open = v9fs_file_open,
 766         .release = v9fs_dir_release,
 767         .lock = v9fs_file_lock_dotl,
 768         .flock = v9fs_file_flock_dotl,
 769         .mmap = generic_file_readonly_mmap,
 770         .fsync = v9fs_file_fsync_dotl,
 771 };