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_debug(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_debug(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                 if (schedule_timeout_interruptible(P9_LOCK_TIMEOUT) != 0)
 208                         break;
 209         }
 210
 211         /* map 9p status to VFS status */
 212         switch (status) {
 213         case P9_LOCK_SUCCESS:
 214                 res = 0;
 215                 break;
 216         case P9_LOCK_BLOCKED:
 217                 res = -EAGAIN;
 218                 break;
 219         case P9_LOCK_ERROR:
 220         case P9_LOCK_GRACE:
 221                 res = -ENOLCK;
 222                 break;
 223         default:
 224                 BUG();
 225         }
 226
 227         /*
 228          * incase server returned error for lock request, revert
 229          * it locally
 230          */
 231         if (res < 0 && fl->fl_type != F_UNLCK) {
 232                 fl_type = fl->fl_type;
 233                 fl->fl_type = F_UNLCK;
 234                 res = posix_lock_file_wait(filp, fl);
 235                 fl->fl_type = fl_type;
 236         }
 237 out:
 238         return res;
 239 }
 240
 241 static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
 242 {
 243         struct p9_getlock glock;
 244         struct p9_fid *fid;
 245         int res = 0;
 246
 247         fid = filp->private_data;
 248         BUG_ON(fid == NULL);
 249
 250         posix_test_lock(filp, fl);
 251         /*
 252          * if we have a conflicting lock locally, no need to validate
 253          * with server
 254          */
 255         if (fl->fl_type != F_UNLCK)
 256                 return res;
 257
 258         /* convert posix lock to p9 tgetlock args */
 259         memset(&glock, 0, sizeof(glock));
 260         glock.type  = P9_LOCK_TYPE_UNLCK;
 261         glock.start = fl->fl_start;
 262         if (fl->fl_end == OFFSET_MAX)
 263                 glock.length = 0;
 264         else
 265                 glock.length = fl->fl_end - fl->fl_start + 1;
 266         glock.proc_id = fl->fl_pid;
 267         glock.client_id = utsname()->nodename;
 268
 269         res = p9_client_getlock_dotl(fid, &glock);
 270         if (res < 0)
 271                 return res;
 272         /* map 9p lock type to os lock type */
 273         switch (glock.type) {
 274         case P9_LOCK_TYPE_RDLCK:
 275                 fl->fl_type = F_RDLCK;
 276                 break;
 277         case P9_LOCK_TYPE_WRLCK:
 278                 fl->fl_type = F_WRLCK;
 279                 break;
 280         case P9_LOCK_TYPE_UNLCK:
 281                 fl->fl_type = F_UNLCK;
 282                 break;
 283         }
 284         if (glock.type != P9_LOCK_TYPE_UNLCK) {
 285                 fl->fl_start = glock.start;
 286                 if (glock.length == 0)
 287                         fl->fl_end = OFFSET_MAX;
 288                 else
 289                         fl->fl_end = glock.start + glock.length - 1;
 290                 fl->fl_pid = glock.proc_id;
 291         }
 292         return res;
 293 }
 294
 295 /**
 296  * v9fs_file_lock_dotl - lock a file (or directory)
 297  * @filp: file to be locked
 298  * @cmd: lock command
 299  * @fl: file lock structure
 300  *
 301  */
 302
 303 static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
 304 {
 305         struct inode *inode = filp->f_path.dentry->d_inode;
 306         int ret = -ENOLCK;
 307
 308         p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n",
 309                  filp, cmd, fl, filp->f_path.dentry->d_name.name);
 310
 311         /* No mandatory locks */
 312         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 313                 goto out_err;
 314
 315         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 316                 filemap_write_and_wait(inode->i_mapping);
 317                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 318         }
 319
 320         if (IS_SETLK(cmd) || IS_SETLKW(cmd))
 321                 ret = v9fs_file_do_lock(filp, cmd, fl);
 322         else if (IS_GETLK(cmd))
 323                 ret = v9fs_file_getlock(filp, fl);
 324         else
 325                 ret = -EINVAL;
 326 out_err:
 327         return ret;
 328 }
 329
 330 /**
 331  * v9fs_file_flock_dotl - lock a file
 332  * @filp: file to be locked
 333  * @cmd: lock command
 334  * @fl: file lock structure
 335  *
 336  */
 337
 338 static int v9fs_file_flock_dotl(struct file *filp, int cmd,
 339         struct file_lock *fl)
 340 {
 341         struct inode *inode = filp->f_path.dentry->d_inode;
 342         int ret = -ENOLCK;
 343
 344         p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n",
 345                  filp, cmd, fl, filp->f_path.dentry->d_name.name);
 346
 347         /* No mandatory locks */
 348         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 349                 goto out_err;
 350
 351         if (!(fl->fl_flags & FL_FLOCK))
 352                 goto out_err;
 353
 354         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 355                 filemap_write_and_wait(inode->i_mapping);
 356                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 357         }
 358         /* Convert flock to posix lock */
 359         fl->fl_owner = (fl_owner_t)filp;
 360         fl->fl_start = 0;
 361         fl->fl_end = OFFSET_MAX;
 362         fl->fl_flags |= FL_POSIX;
 363         fl->fl_flags ^= FL_FLOCK;
 364
 365         if (IS_SETLK(cmd) | IS_SETLKW(cmd))
 366                 ret = v9fs_file_do_lock(filp, cmd, fl);
 367         else
 368                 ret = -EINVAL;
 369 out_err:
 370         return ret;
 371 }
 372
 373 /**
 374  * v9fs_fid_readn - read from a fid
 375  * @fid: fid to read
 376  * @data: data buffer to read data into
 377  * @udata: user data buffer to read data into
 378  * @count: size of buffer
 379  * @offset: offset at which to read data
 380  *
 381  */
 382 ssize_t
 383 v9fs_fid_readn(struct p9_fid *fid, char *data, char __user *udata, u32 count,
 384                u64 offset)
 385 {
 386         int n, total, size;
 387
 388         p9_debug(P9_DEBUG_VFS, "fid %d offset %llu count %d\n",
 389                  fid->fid, (long long unsigned)offset, count);
 390         n = 0;
 391         total = 0;
 392         size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
 393         do {
 394                 n = p9_client_read(fid, data, udata, offset, count);
 395                 if (n <= 0)
 396                         break;
 397
 398                 if (data)
 399                         data += n;
 400                 if (udata)
 401                         udata += n;
 402
 403                 offset += n;
 404                 count -= n;
 405                 total += n;
 406         } while (count > 0 && n == size);
 407
 408         if (n < 0)
 409                 total = n;
 410
 411         return total;
 412 }
 413
 414 /**
 415  * v9fs_file_readn - read from a file
 416  * @filp: file pointer to read
 417  * @data: data buffer to read data into
 418  * @udata: user data buffer to read data into
 419  * @count: size of buffer
 420  * @offset: offset at which to read data
 421  *
 422  */
 423 ssize_t
 424 v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
 425                u64 offset)
 426 {
 427         return v9fs_fid_readn(filp->private_data, data, udata, count, offset);
 428 }
 429
 430 /**
 431  * v9fs_file_read - read from a file
 432  * @filp: file pointer to read
 433  * @udata: user data buffer to read data into
 434  * @count: size of buffer
 435  * @offset: offset at which to read data
 436  *
 437  */
 438
 439 static ssize_t
 440 v9fs_file_read(struct file *filp, char __user *udata, size_t count,
 441                loff_t * offset)
 442 {
 443         int ret;
 444         struct p9_fid *fid;
 445         size_t size;
 446
 447         p9_debug(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset);
 448         fid = filp->private_data;
 449
 450         size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
 451         if (count > size)
 452                 ret = v9fs_file_readn(filp, NULL, udata, count, *offset);
 453         else
 454                 ret = p9_client_read(fid, NULL, udata, *offset, count);
 455
 456         if (ret > 0)
 457                 *offset += ret;
 458
 459         return ret;
 460 }
 461
 462 ssize_t
 463 v9fs_file_write_internal(struct inode *inode, struct p9_fid *fid,
 464                          const char __user *data, size_t count,
 465                          loff_t *offset, int invalidate)
 466 {
 467         int n;
 468         loff_t i_size;
 469         size_t total = 0;
 470         struct p9_client *clnt;
 471         loff_t origin = *offset;
 472         unsigned long pg_start, pg_end;
 473
 474         p9_debug(P9_DEBUG_VFS, "data %p count %d offset %x\n",
 475                  data, (int)count, (int)*offset);
 476
 477         clnt = fid->clnt;
 478         do {
 479                 n = p9_client_write(fid, NULL, data+total, origin+total, count);
 480                 if (n <= 0)
 481                         break;
 482                 count -= n;
 483                 total += n;
 484         } while (count > 0);
 485
 486         if (invalidate && (total > 0)) {
 487                 pg_start = origin >> PAGE_CACHE_SHIFT;
 488                 pg_end = (origin + total - 1) >> PAGE_CACHE_SHIFT;
 489                 if (inode->i_mapping && inode->i_mapping->nrpages)
 490                         invalidate_inode_pages2_range(inode->i_mapping,
 491                                                       pg_start, pg_end);
 492                 *offset += total;
 493                 i_size = i_size_read(inode);
 494                 if (*offset > i_size) {
 495                         inode_add_bytes(inode, *offset - i_size);
 496                         i_size_write(inode, *offset);
 497                 }
 498         }
 499         if (n < 0)
 500                 return n;
 501
 502         return total;
 503 }
 504
 505 /**
 506  * v9fs_file_write - write to a file
 507  * @filp: file pointer to write
 508  * @data: data buffer to write data from
 509  * @count: size of buffer
 510  * @offset: offset at which to write data
 511  *
 512  */
 513 static ssize_t
 514 v9fs_file_write(struct file *filp, const char __user * data,
 515                 size_t count, loff_t *offset)
 516 {
 517         ssize_t retval = 0;
 518         loff_t origin = *offset;
 519
 520
 521         retval = generic_write_checks(filp, &origin, &count, 0);
 522         if (retval)
 523                 goto out;
 524
 525         retval = -EINVAL;
 526         if ((ssize_t) count < 0)
 527                 goto out;
 528         retval = 0;
 529         if (!count)
 530                 goto out;
 531
 532         retval = v9fs_file_write_internal(filp->f_path.dentry->d_inode,
 533                                         filp->private_data,
 534                                         data, count, &origin, 1);
 535         /* update offset on successful write */
 536         if (retval > 0)
 537                 *offset = origin;
 538 out:
 539         return retval;
 540 }
 541
 542
 543 static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
 544                            int datasync)
 545 {
 546         struct p9_fid *fid;
 547         struct inode *inode = filp->f_mapping->host;
 548         struct p9_wstat wstat;
 549         int retval;
 550
 551         retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
 552         if (retval)
 553                 return retval;
 554
 555         mutex_lock(&inode->i_mutex);
 556         p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
 557
 558         fid = filp->private_data;
 559         v9fs_blank_wstat(&wstat);
 560
 561         retval = p9_client_wstat(fid, &wstat);
 562         mutex_unlock(&inode->i_mutex);
 563
 564         return retval;
 565 }
 566
 567 int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
 568                          int datasync)
 569 {
 570         struct p9_fid *fid;
 571         struct inode *inode = filp->f_mapping->host;
 572         int retval;
 573
 574         retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
 575         if (retval)
 576                 return retval;
 577
 578         mutex_lock(&inode->i_mutex);
 579         p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
 580
 581         fid = filp->private_data;
 582
 583         retval = p9_client_fsync(fid, datasync);
 584         mutex_unlock(&inode->i_mutex);
 585
 586         return retval;
 587 }
 588
 589 static int
 590 v9fs_file_mmap(struct file *file, struct vm_area_struct *vma)
 591 {
 592         int retval;
 593
 594         retval = generic_file_mmap(file, vma);
 595         if (!retval)
 596                 vma->vm_ops = &v9fs_file_vm_ops;
 597
 598         return retval;
 599 }
 600
 601 static int
 602 v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 603 {
 604         struct v9fs_inode *v9inode;
 605         struct page *page = vmf->page;
 606         struct file *filp = vma->vm_file;
 607         struct inode *inode = filp->f_path.dentry->d_inode;
 608
 609
 610         p9_debug(P9_DEBUG_VFS, "page %p fid %lx\n",
 611                  page, (unsigned long)filp->private_data);
 612
 613         /* Update file times before taking page lock */
 614         file_update_time(filp);
 615
 616         v9inode = V9FS_I(inode);
 617         /* make sure the cache has finished storing the page */
 618         v9fs_fscache_wait_on_page_write(inode, page);
 619         BUG_ON(!v9inode->writeback_fid);
 620         lock_page(page);
 621         if (page->mapping != inode->i_mapping)
 622                 goto out_unlock;
 623
 624         return VM_FAULT_LOCKED;
 625 out_unlock:
 626         unlock_page(page);
 627         return VM_FAULT_NOPAGE;
 628 }
 629
 630 static ssize_t
 631 v9fs_direct_read(struct file *filp, char __user *udata, size_t count,
 632                  loff_t *offsetp)
 633 {
 634         loff_t size, offset;
 635         struct inode *inode;
 636         struct address_space *mapping;
 637
 638         offset = *offsetp;
 639         mapping = filp->f_mapping;
 640         inode = mapping->host;
 641         if (!count)
 642                 return 0;
 643         size = i_size_read(inode);
 644         if (offset < size)
 645                 filemap_write_and_wait_range(mapping, offset,
 646                                              offset + count - 1);
 647
 648         return v9fs_file_read(filp, udata, count, offsetp);
 649 }
 650
 651 /**
 652  * v9fs_cached_file_read - read from a file
 653  * @filp: file pointer to read
 654  * @udata: user data buffer to read data into
 655  * @count: size of buffer
 656  * @offset: offset at which to read data
 657  *
 658  */
 659 static ssize_t
 660 v9fs_cached_file_read(struct file *filp, char __user *data, size_t count,
 661                       loff_t *offset)
 662 {
 663         if (filp->f_flags & O_DIRECT)
 664                 return v9fs_direct_read(filp, data, count, offset);
 665         return do_sync_read(filp, data, count, offset);
 666 }
 667
 668 static ssize_t
 669 v9fs_direct_write(struct file *filp, const char __user * data,
 670                   size_t count, loff_t *offsetp)
 671 {
 672         loff_t offset;
 673         ssize_t retval;
 674         struct inode *inode;
 675         struct address_space *mapping;
 676
 677         offset = *offsetp;
 678         mapping = filp->f_mapping;
 679         inode = mapping->host;
 680         if (!count)
 681                 return 0;
 682
 683         mutex_lock(&inode->i_mutex);
 684         retval = filemap_write_and_wait_range(mapping, offset,
 685                                               offset + count - 1);
 686         if (retval)
 687                 goto err_out;
 688         /*
 689          * After a write we want buffered reads to be sure to go to disk to get
 690          * the new data.  We invalidate clean cached page from the region we're
 691          * about to write.  We do this *before* the write so that if we fail
 692          * here we fall back to buffered write
 693          */
 694         if (mapping->nrpages) {
 695                 pgoff_t pg_start = offset >> PAGE_CACHE_SHIFT;
 696                 pgoff_t pg_end   = (offset + count - 1) >> PAGE_CACHE_SHIFT;
 697
 698                 retval = invalidate_inode_pages2_range(mapping,
 699                                                         pg_start, pg_end);
 700                 /*
 701                  * If a page can not be invalidated, fall back
 702                  * to buffered write.
 703                  */
 704                 if (retval) {
 705                         if (retval == -EBUSY)
 706                                 goto buff_write;
 707                         goto err_out;
 708                 }
 709         }
 710         retval = v9fs_file_write(filp, data, count, offsetp);
 711 err_out:
 712         mutex_unlock(&inode->i_mutex);
 713         return retval;
 714
 715 buff_write:
 716         mutex_unlock(&inode->i_mutex);
 717         return do_sync_write(filp, data, count, offsetp);
 718 }
 719
 720 /**
 721  * v9fs_cached_file_write - write to a file
 722  * @filp: file pointer to write
 723  * @data: data buffer to write data from
 724  * @count: size of buffer
 725  * @offset: offset at which to write data
 726  *
 727  */
 728 static ssize_t
 729 v9fs_cached_file_write(struct file *filp, const char __user * data,
 730                        size_t count, loff_t *offset)
 731 {
 732
 733         if (filp->f_flags & O_DIRECT)
 734                 return v9fs_direct_write(filp, data, count, offset);
 735         return do_sync_write(filp, data, count, offset);
 736 }
 737
 738 static const struct vm_operations_struct v9fs_file_vm_ops = {
 739         .fault = filemap_fault,
 740         .page_mkwrite = v9fs_vm_page_mkwrite,
 741 };
 742
 743
 744 const struct file_operations v9fs_cached_file_operations = {
 745         .llseek = generic_file_llseek,
 746         .read = v9fs_cached_file_read,
 747         .write = v9fs_cached_file_write,
 748         .aio_read = generic_file_aio_read,
 749         .aio_write = generic_file_aio_write,
 750         .open = v9fs_file_open,
 751         .release = v9fs_dir_release,
 752         .lock = v9fs_file_lock,
 753         .mmap = v9fs_file_mmap,
 754         .fsync = v9fs_file_fsync,
 755 };
 756
 757 const struct file_operations v9fs_cached_file_operations_dotl = {
 758         .llseek = generic_file_llseek,
 759         .read = v9fs_cached_file_read,
 760         .write = v9fs_cached_file_write,
 761         .aio_read = generic_file_aio_read,
 762         .aio_write = generic_file_aio_write,
 763         .open = v9fs_file_open,
 764         .release = v9fs_dir_release,
 765         .lock = v9fs_file_lock_dotl,
 766         .flock = v9fs_file_flock_dotl,
 767         .mmap = v9fs_file_mmap,
 768         .fsync = v9fs_file_fsync_dotl,
 769 };
 770
 771 const struct file_operations v9fs_file_operations = {
 772         .llseek = generic_file_llseek,
 773         .read = v9fs_file_read,
 774         .write = v9fs_file_write,
 775         .open = v9fs_file_open,
 776         .release = v9fs_dir_release,
 777         .lock = v9fs_file_lock,
 778         .mmap = generic_file_readonly_mmap,
 779         .fsync = v9fs_file_fsync,
 780 };
 781
 782 const struct file_operations v9fs_file_operations_dotl = {
 783         .llseek = generic_file_llseek,
 784         .read = v9fs_file_read,
 785         .write = v9fs_file_write,
 786         .open = v9fs_file_open,
 787         .release = v9fs_dir_release,
 788         .lock = v9fs_file_lock_dotl,
 789         .flock = v9fs_file_flock_dotl,
 790         .mmap = generic_file_readonly_mmap,
 791         .fsync = v9fs_file_fsync_dotl,
 792 };