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 static const struct vm_operations_struct v9fs_mmap_file_vm_ops;
  49
  50 /**
  51  * v9fs_file_open - open a file (or directory)
  52  * @inode: inode to be opened
  53  * @file: file being opened
  54  *
  55  */
  56
  57 int v9fs_file_open(struct inode *inode, struct file *file)
  58 {
  59         int err;
  60         struct v9fs_inode *v9inode;
  61         struct v9fs_session_info *v9ses;
  62         struct p9_fid *fid;
  63         int omode;
  64
  65         p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
  66         v9inode = V9FS_I(inode);
  67         v9ses = v9fs_inode2v9ses(inode);
  68         if (v9fs_proto_dotl(v9ses))
  69                 omode = v9fs_open_to_dotl_flags(file->f_flags);
  70         else
  71                 omode = v9fs_uflags2omode(file->f_flags,
  72                                         v9fs_proto_dotu(v9ses));
  73         fid = file->private_data;
  74         if (!fid) {
  75                 fid = v9fs_fid_clone(file->f_path.dentry);
  76                 if (IS_ERR(fid))
  77                         return PTR_ERR(fid);
  78
  79                 err = p9_client_open(fid, omode);
  80                 if (err < 0) {
  81                         p9_client_clunk(fid);
  82                         return err;
  83                 }
  84                 if ((file->f_flags & O_APPEND) &&
  85                         (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
  86                         generic_file_llseek(file, 0, SEEK_END);
  87         }
  88
  89         file->private_data = fid;
  90         mutex_lock(&v9inode->v_mutex);
  91         if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
  92             !v9inode->writeback_fid &&
  93             ((file->f_flags & O_ACCMODE) != O_RDONLY)) {
  94                 /*
  95                  * clone a fid and add it to writeback_fid
  96                  * we do it during open time instead of
  97                  * page dirty time via write_begin/page_mkwrite
  98                  * because we want write after unlink usecase
  99                  * to work.
 100                  */
 101                 fid = v9fs_writeback_fid(file->f_path.dentry);
 102                 if (IS_ERR(fid)) {
 103                         err = PTR_ERR(fid);
 104                         mutex_unlock(&v9inode->v_mutex);
 105                         goto out_error;
 106                 }
 107                 v9inode->writeback_fid = (void *) fid;
 108         }
 109         mutex_unlock(&v9inode->v_mutex);
 110         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 111                 v9fs_cache_inode_set_cookie(inode, file);
 112         return 0;
 113 out_error:
 114         p9_client_clunk(file->private_data);
 115         file->private_data = NULL;
 116         return err;
 117 }
 118
 119 /**
 120  * v9fs_file_lock - lock a file (or directory)
 121  * @filp: file to be locked
 122  * @cmd: lock command
 123  * @fl: file lock structure
 124  *
 125  * Bugs: this looks like a local only lock, we should extend into 9P
 126  *       by using open exclusive
 127  */
 128
 129 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 130 {
 131         int res = 0;
 132         struct inode *inode = file_inode(filp);
 133
 134         p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 135
 136         /* No mandatory locks */
 137         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 138                 return -ENOLCK;
 139
 140         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 141                 filemap_write_and_wait(inode->i_mapping);
 142                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 143         }
 144
 145         return res;
 146 }
 147
 148 static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
 149 {
 150         struct p9_flock flock;
 151         struct p9_fid *fid;
 152         uint8_t status;
 153         int res = 0;
 154         unsigned char fl_type;
 155
 156         fid = filp->private_data;
 157         BUG_ON(fid == NULL);
 158
 159         if ((fl->fl_flags & FL_POSIX) != FL_POSIX)
 160                 BUG();
 161
 162         res = posix_lock_file_wait(filp, fl);
 163         if (res < 0)
 164                 goto out;
 165
 166         /* convert posix lock to p9 tlock args */
 167         memset(&flock, 0, sizeof(flock));
 168         /* map the lock type */
 169         switch (fl->fl_type) {
 170         case F_RDLCK:
 171                 flock.type = P9_LOCK_TYPE_RDLCK;
 172                 break;
 173         case F_WRLCK:
 174                 flock.type = P9_LOCK_TYPE_WRLCK;
 175                 break;
 176         case F_UNLCK:
 177                 flock.type = P9_LOCK_TYPE_UNLCK;
 178                 break;
 179         }
 180         flock.start = fl->fl_start;
 181         if (fl->fl_end == OFFSET_MAX)
 182                 flock.length = 0;
 183         else
 184                 flock.length = fl->fl_end - fl->fl_start + 1;
 185         flock.proc_id = fl->fl_pid;
 186         flock.client_id = fid->clnt->name;
 187         if (IS_SETLKW(cmd))
 188                 flock.flags = P9_LOCK_FLAGS_BLOCK;
 189
 190         /*
 191          * if its a blocked request and we get P9_LOCK_BLOCKED as the status
 192          * for lock request, keep on trying
 193          */
 194         for (;;) {
 195                 res = p9_client_lock_dotl(fid, &flock, &status);
 196                 if (res < 0)
 197                         break;
 198
 199                 if (status != P9_LOCK_BLOCKED)
 200                         break;
 201                 if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
 202                         break;
 203                 if (schedule_timeout_interruptible(P9_LOCK_TIMEOUT) != 0)
 204                         break;
 205         }
 206
 207         /* map 9p status to VFS status */
 208         switch (status) {
 209         case P9_LOCK_SUCCESS:
 210                 res = 0;
 211                 break;
 212         case P9_LOCK_BLOCKED:
 213                 res = -EAGAIN;
 214                 break;
 215         case P9_LOCK_ERROR:
 216         case P9_LOCK_GRACE:
 217                 res = -ENOLCK;
 218                 break;
 219         default:
 220                 BUG();
 221         }
 222
 223         /*
 224          * incase server returned error for lock request, revert
 225          * it locally
 226          */
 227         if (res < 0 && fl->fl_type != F_UNLCK) {
 228                 fl_type = fl->fl_type;
 229                 fl->fl_type = F_UNLCK;
 230                 res = posix_lock_file_wait(filp, fl);
 231                 fl->fl_type = fl_type;
 232         }
 233 out:
 234         return res;
 235 }
 236
 237 static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
 238 {
 239         struct p9_getlock glock;
 240         struct p9_fid *fid;
 241         int res = 0;
 242
 243         fid = filp->private_data;
 244         BUG_ON(fid == NULL);
 245
 246         posix_test_lock(filp, fl);
 247         /*
 248          * if we have a conflicting lock locally, no need to validate
 249          * with server
 250          */
 251         if (fl->fl_type != F_UNLCK)
 252                 return res;
 253
 254         /* convert posix lock to p9 tgetlock args */
 255         memset(&glock, 0, sizeof(glock));
 256         glock.type  = P9_LOCK_TYPE_UNLCK;
 257         glock.start = fl->fl_start;
 258         if (fl->fl_end == OFFSET_MAX)
 259                 glock.length = 0;
 260         else
 261                 glock.length = fl->fl_end - fl->fl_start + 1;
 262         glock.proc_id = fl->fl_pid;
 263         glock.client_id = fid->clnt->name;
 264
 265         res = p9_client_getlock_dotl(fid, &glock);
 266         if (res < 0)
 267                 return res;
 268         /* map 9p lock type to os lock type */
 269         switch (glock.type) {
 270         case P9_LOCK_TYPE_RDLCK:
 271                 fl->fl_type = F_RDLCK;
 272                 break;
 273         case P9_LOCK_TYPE_WRLCK:
 274                 fl->fl_type = F_WRLCK;
 275                 break;
 276         case P9_LOCK_TYPE_UNLCK:
 277                 fl->fl_type = F_UNLCK;
 278                 break;
 279         }
 280         if (glock.type != P9_LOCK_TYPE_UNLCK) {
 281                 fl->fl_start = glock.start;
 282                 if (glock.length == 0)
 283                         fl->fl_end = OFFSET_MAX;
 284                 else
 285                         fl->fl_end = glock.start + glock.length - 1;
 286                 fl->fl_pid = glock.proc_id;
 287         }
 288         return res;
 289 }
 290
 291 /**
 292  * v9fs_file_lock_dotl - lock a file (or directory)
 293  * @filp: file to be locked
 294  * @cmd: lock command
 295  * @fl: file lock structure
 296  *
 297  */
 298
 299 static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
 300 {
 301         struct inode *inode = file_inode(filp);
 302         int ret = -ENOLCK;
 303
 304         p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n",
 305                  filp, cmd, fl, filp->f_path.dentry->d_name.name);
 306
 307         /* No mandatory locks */
 308         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 309                 goto out_err;
 310
 311         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 312                 filemap_write_and_wait(inode->i_mapping);
 313                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 314         }
 315
 316         if (IS_SETLK(cmd) || IS_SETLKW(cmd))
 317                 ret = v9fs_file_do_lock(filp, cmd, fl);
 318         else if (IS_GETLK(cmd))
 319                 ret = v9fs_file_getlock(filp, fl);
 320         else
 321                 ret = -EINVAL;
 322 out_err:
 323         return ret;
 324 }
 325
 326 /**
 327  * v9fs_file_flock_dotl - lock a file
 328  * @filp: file to be locked
 329  * @cmd: lock command
 330  * @fl: file lock structure
 331  *
 332  */
 333
 334 static int v9fs_file_flock_dotl(struct file *filp, int cmd,
 335         struct file_lock *fl)
 336 {
 337         struct inode *inode = file_inode(filp);
 338         int ret = -ENOLCK;
 339
 340         p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n",
 341                  filp, cmd, fl, filp->f_path.dentry->d_name.name);
 342
 343         /* No mandatory locks */
 344         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 345                 goto out_err;
 346
 347         if (!(fl->fl_flags & FL_FLOCK))
 348                 goto out_err;
 349
 350         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 351                 filemap_write_and_wait(inode->i_mapping);
 352                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 353         }
 354         /* Convert flock to posix lock */
 355         fl->fl_flags |= FL_POSIX;
 356         fl->fl_flags ^= FL_FLOCK;
 357
 358         if (IS_SETLK(cmd) | IS_SETLKW(cmd))
 359                 ret = v9fs_file_do_lock(filp, cmd, fl);
 360         else
 361                 ret = -EINVAL;
 362 out_err:
 363         return ret;
 364 }
 365
 366 /**
 367  * v9fs_fid_readn - read from a fid
 368  * @fid: fid to read
 369  * @data: data buffer to read data into
 370  * @udata: user data buffer to read data into
 371  * @count: size of buffer
 372  * @offset: offset at which to read data
 373  *
 374  */
 375 ssize_t
 376 v9fs_fid_readn(struct p9_fid *fid, char *data, char __user *udata, u32 count,
 377                u64 offset)
 378 {
 379         int n, total, size;
 380
 381         p9_debug(P9_DEBUG_VFS, "fid %d offset %llu count %d\n",
 382                  fid->fid, (long long unsigned)offset, count);
 383         n = 0;
 384         total = 0;
 385         size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
 386         do {
 387                 n = p9_client_read(fid, data, udata, offset, count);
 388                 if (n <= 0)
 389                         break;
 390
 391                 if (data)
 392                         data += n;
 393                 if (udata)
 394                         udata += n;
 395
 396                 offset += n;
 397                 count -= n;
 398                 total += n;
 399         } while (count > 0 && n == size);
 400
 401         if (n < 0)
 402                 total = n;
 403
 404         return total;
 405 }
 406
 407 /**
 408  * v9fs_file_readn - read from a file
 409  * @filp: file pointer to read
 410  * @data: data buffer to read data into
 411  * @udata: user data buffer to read data into
 412  * @count: size of buffer
 413  * @offset: offset at which to read data
 414  *
 415  */
 416 ssize_t
 417 v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
 418                u64 offset)
 419 {
 420         return v9fs_fid_readn(filp->private_data, data, udata, count, offset);
 421 }
 422
 423 /**
 424  * v9fs_file_read - read from a file
 425  * @filp: file pointer to read
 426  * @udata: user data buffer to read data into
 427  * @count: size of buffer
 428  * @offset: offset at which to read data
 429  *
 430  */
 431
 432 static ssize_t
 433 v9fs_file_read(struct file *filp, char __user *udata, size_t count,
 434                loff_t * offset)
 435 {
 436         int ret;
 437         struct p9_fid *fid;
 438         size_t size;
 439
 440         p9_debug(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset);
 441         fid = filp->private_data;
 442
 443         size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
 444         if (count > size)
 445                 ret = v9fs_file_readn(filp, NULL, udata, count, *offset);
 446         else
 447                 ret = p9_client_read(fid, NULL, udata, *offset, count);
 448
 449         if (ret > 0)
 450                 *offset += ret;
 451
 452         return ret;
 453 }
 454
 455 ssize_t
 456 v9fs_file_write_internal(struct inode *inode, struct p9_fid *fid,
 457                          const char __user *data, size_t count,
 458                          loff_t *offset, int invalidate)
 459 {
 460         int n;
 461         loff_t i_size;
 462         size_t total = 0;
 463         loff_t origin = *offset;
 464         unsigned long pg_start, pg_end;
 465
 466         p9_debug(P9_DEBUG_VFS, "data %p count %d offset %x\n",
 467                  data, (int)count, (int)*offset);
 468
 469         do {
 470                 n = p9_client_write(fid, NULL, data+total, origin+total, count);
 471                 if (n <= 0)
 472                         break;
 473                 count -= n;
 474                 total += n;
 475         } while (count > 0);
 476
 477         if (invalidate && (total > 0)) {
 478                 pg_start = origin >> PAGE_CACHE_SHIFT;
 479                 pg_end = (origin + total - 1) >> PAGE_CACHE_SHIFT;
 480                 if (inode->i_mapping && inode->i_mapping->nrpages)
 481                         invalidate_inode_pages2_range(inode->i_mapping,
 482                                                       pg_start, pg_end);
 483                 *offset += total;
 484                 i_size = i_size_read(inode);
 485                 if (*offset > i_size) {
 486                         inode_add_bytes(inode, *offset - i_size);
 487                         i_size_write(inode, *offset);
 488                 }
 489         }
 490         if (n < 0)
 491                 return n;
 492
 493         return total;
 494 }
 495
 496 /**
 497  * v9fs_file_write - write to a file
 498  * @filp: file pointer to write
 499  * @data: data buffer to write data from
 500  * @count: size of buffer
 501  * @offset: offset at which to write data
 502  *
 503  */
 504 static ssize_t
 505 v9fs_file_write(struct file *filp, const char __user * data,
 506                 size_t count, loff_t *offset)
 507 {
 508         ssize_t retval = 0;
 509         loff_t origin = *offset;
 510
 511
 512         retval = generic_write_checks(filp, &origin, &count, 0);
 513         if (retval)
 514                 goto out;
 515
 516         retval = -EINVAL;
 517         if ((ssize_t) count < 0)
 518                 goto out;
 519         retval = 0;
 520         if (!count)
 521                 goto out;
 522
 523         retval = v9fs_file_write_internal(file_inode(filp),
 524                                         filp->private_data,
 525                                         data, count, &origin, 1);
 526         /* update offset on successful write */
 527         if (retval > 0)
 528                 *offset = origin;
 529 out:
 530         return retval;
 531 }
 532
 533
 534 static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
 535                            int datasync)
 536 {
 537         struct p9_fid *fid;
 538         struct inode *inode = filp->f_mapping->host;
 539         struct p9_wstat wstat;
 540         int retval;
 541
 542         retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
 543         if (retval)
 544                 return retval;
 545
 546         mutex_lock(&inode->i_mutex);
 547         p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
 548
 549         fid = filp->private_data;
 550         v9fs_blank_wstat(&wstat);
 551
 552         retval = p9_client_wstat(fid, &wstat);
 553         mutex_unlock(&inode->i_mutex);
 554
 555         return retval;
 556 }
 557
 558 int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
 559                          int datasync)
 560 {
 561         struct p9_fid *fid;
 562         struct inode *inode = filp->f_mapping->host;
 563         int retval;
 564
 565         retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
 566         if (retval)
 567                 return retval;
 568
 569         mutex_lock(&inode->i_mutex);
 570         p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
 571
 572         fid = filp->private_data;
 573
 574         retval = p9_client_fsync(fid, datasync);
 575         mutex_unlock(&inode->i_mutex);
 576
 577         return retval;
 578 }
 579
 580 static int
 581 v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
 582 {
 583         int retval;
 584
 585
 586         retval = generic_file_mmap(filp, vma);
 587         if (!retval)
 588                 vma->vm_ops = &v9fs_file_vm_ops;
 589
 590         return retval;
 591 }
 592
 593 static int
 594 v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma)
 595 {
 596         int retval;
 597         struct inode *inode;
 598         struct v9fs_inode *v9inode;
 599         struct p9_fid *fid;
 600
 601         inode = file_inode(filp);
 602         v9inode = V9FS_I(inode);
 603         mutex_lock(&v9inode->v_mutex);
 604         if (!v9inode->writeback_fid &&
 605             (vma->vm_flags & VM_WRITE)) {
 606                 /*
 607                  * clone a fid and add it to writeback_fid
 608                  * we do it during mmap instead of
 609                  * page dirty time via write_begin/page_mkwrite
 610                  * because we want write after unlink usecase
 611                  * to work.
 612                  */
 613                 fid = v9fs_writeback_fid(filp->f_path.dentry);
 614                 if (IS_ERR(fid)) {
 615                         retval = PTR_ERR(fid);
 616                         mutex_unlock(&v9inode->v_mutex);
 617                         return retval;
 618                 }
 619                 v9inode->writeback_fid = (void *) fid;
 620         }
 621         mutex_unlock(&v9inode->v_mutex);
 622
 623         retval = generic_file_mmap(filp, vma);
 624         if (!retval)
 625                 vma->vm_ops = &v9fs_mmap_file_vm_ops;
 626
 627         return retval;
 628 }
 629
 630 static int
 631 v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 632 {
 633         struct v9fs_inode *v9inode;
 634         struct page *page = vmf->page;
 635         struct file *filp = vma->vm_file;
 636         struct inode *inode = file_inode(filp);
 637
 638
 639         p9_debug(P9_DEBUG_VFS, "page %p fid %lx\n",
 640                  page, (unsigned long)filp->private_data);
 641
 642         /* Update file times before taking page lock */
 643         file_update_time(filp);
 644
 645         v9inode = V9FS_I(inode);
 646         /* make sure the cache has finished storing the page */
 647         v9fs_fscache_wait_on_page_write(inode, page);
 648         BUG_ON(!v9inode->writeback_fid);
 649         lock_page(page);
 650         if (page->mapping != inode->i_mapping)
 651                 goto out_unlock;
 652         wait_for_stable_page(page);
 653
 654         return VM_FAULT_LOCKED;
 655 out_unlock:
 656         unlock_page(page);
 657         return VM_FAULT_NOPAGE;
 658 }
 659
 660 static ssize_t
 661 v9fs_direct_read(struct file *filp, char __user *udata, size_t count,
 662                  loff_t *offsetp)
 663 {
 664         loff_t size, offset;
 665         struct inode *inode;
 666         struct address_space *mapping;
 667
 668         offset = *offsetp;
 669         mapping = filp->f_mapping;
 670         inode = mapping->host;
 671         if (!count)
 672                 return 0;
 673         size = i_size_read(inode);
 674         if (offset < size)
 675                 filemap_write_and_wait_range(mapping, offset,
 676                                              offset + count - 1);
 677
 678         return v9fs_file_read(filp, udata, count, offsetp);
 679 }
 680
 681 /**
 682  * v9fs_cached_file_read - read from a file
 683  * @filp: file pointer to read
 684  * @data: user data buffer to read data into
 685  * @count: size of buffer
 686  * @offset: offset at which to read data
 687  *
 688  */
 689 static ssize_t
 690 v9fs_cached_file_read(struct file *filp, char __user *data, size_t count,
 691                       loff_t *offset)
 692 {
 693         if (filp->f_flags & O_DIRECT)
 694                 return v9fs_direct_read(filp, data, count, offset);
 695         return new_sync_read(filp, data, count, offset);
 696 }
 697
 698 /**
 699  * v9fs_mmap_file_read - read from a file
 700  * @filp: file pointer to read
 701  * @data: user data buffer to read data into
 702  * @count: size of buffer
 703  * @offset: offset at which to read data
 704  *
 705  */
 706 static ssize_t
 707 v9fs_mmap_file_read(struct file *filp, char __user *data, size_t count,
 708                       loff_t *offset)
 709 {
 710         /* TODO: Check if there are dirty pages */
 711         return v9fs_file_read(filp, data, count, offset);
 712 }
 713
 714 static ssize_t
 715 v9fs_direct_write(struct file *filp, const char __user * data,
 716                   size_t count, loff_t *offsetp)
 717 {
 718         loff_t offset;
 719         ssize_t retval;
 720         struct inode *inode;
 721         struct address_space *mapping;
 722
 723         offset = *offsetp;
 724         mapping = filp->f_mapping;
 725         inode = mapping->host;
 726         if (!count)
 727                 return 0;
 728
 729         mutex_lock(&inode->i_mutex);
 730         retval = filemap_write_and_wait_range(mapping, offset,
 731                                               offset + count - 1);
 732         if (retval)
 733                 goto err_out;
 734         /*
 735          * After a write we want buffered reads to be sure to go to disk to get
 736          * the new data.  We invalidate clean cached page from the region we're
 737          * about to write.  We do this *before* the write so that if we fail
 738          * here we fall back to buffered write
 739          */
 740         if (mapping->nrpages) {
 741                 pgoff_t pg_start = offset >> PAGE_CACHE_SHIFT;
 742                 pgoff_t pg_end   = (offset + count - 1) >> PAGE_CACHE_SHIFT;
 743
 744                 retval = invalidate_inode_pages2_range(mapping,
 745                                                         pg_start, pg_end);
 746                 /*
 747                  * If a page can not be invalidated, fall back
 748                  * to buffered write.
 749                  */
 750                 if (retval) {
 751                         if (retval == -EBUSY)
 752                                 goto buff_write;
 753                         goto err_out;
 754                 }
 755         }
 756         retval = v9fs_file_write(filp, data, count, offsetp);
 757 err_out:
 758         mutex_unlock(&inode->i_mutex);
 759         return retval;
 760
 761 buff_write:
 762         mutex_unlock(&inode->i_mutex);
 763         return new_sync_write(filp, data, count, offsetp);
 764 }
 765
 766 /**
 767  * v9fs_cached_file_write - write to a file
 768  * @filp: file pointer to write
 769  * @data: data buffer to write data from
 770  * @count: size of buffer
 771  * @offset: offset at which to write data
 772  *
 773  */
 774 static ssize_t
 775 v9fs_cached_file_write(struct file *filp, const char __user * data,
 776                        size_t count, loff_t *offset)
 777 {
 778
 779         if (filp->f_flags & O_DIRECT)
 780                 return v9fs_direct_write(filp, data, count, offset);
 781         return new_sync_write(filp, data, count, offset);
 782 }
 783
 784
 785 /**
 786  * v9fs_mmap_file_write - write to a file
 787  * @filp: file pointer to write
 788  * @data: data buffer to write data from
 789  * @count: size of buffer
 790  * @offset: offset at which to write data
 791  *
 792  */
 793 static ssize_t
 794 v9fs_mmap_file_write(struct file *filp, const char __user *data,
 795                        size_t count, loff_t *offset)
 796 {
 797         /*
 798          * TODO: invalidate mmaps on filp's inode between
 799          * offset and offset+count
 800          */
 801         return v9fs_file_write(filp, data, count, offset);
 802 }
 803
 804 static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
 805 {
 806         struct inode *inode;
 807
 808         struct writeback_control wbc = {
 809                 .nr_to_write = LONG_MAX,
 810                 .sync_mode = WB_SYNC_ALL,
 811                 .range_start = vma->vm_pgoff * PAGE_SIZE,
 812                  /* absolute end, byte at end included */
 813                 .range_end = vma->vm_pgoff * PAGE_SIZE +
 814                         (vma->vm_end - vma->vm_start - 1),
 815         };
 816
 817
 818         p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);
 819
 820         inode = file_inode(vma->vm_file);
 821
 822         if (!mapping_cap_writeback_dirty(inode->i_mapping))
 823                 wbc.nr_to_write = 0;
 824
 825         might_sleep();
 826         sync_inode(inode, &wbc);
 827 }
 828
 829
 830 static const struct vm_operations_struct v9fs_file_vm_ops = {
 831         .fault = filemap_fault,
 832         .map_pages = filemap_map_pages,
 833         .page_mkwrite = v9fs_vm_page_mkwrite,
 834         .remap_pages = generic_file_remap_pages,
 835 };
 836
 837 static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
 838         .close = v9fs_mmap_vm_close,
 839         .fault = filemap_fault,
 840         .map_pages = filemap_map_pages,
 841         .page_mkwrite = v9fs_vm_page_mkwrite,
 842         .remap_pages = generic_file_remap_pages,
 843 };
 844
 845
 846 const struct file_operations v9fs_cached_file_operations = {
 847         .llseek = generic_file_llseek,
 848         .read = v9fs_cached_file_read,
 849         .write = v9fs_cached_file_write,
 850         .read_iter = generic_file_read_iter,
 851         .write_iter = generic_file_write_iter,
 852         .open = v9fs_file_open,
 853         .release = v9fs_dir_release,
 854         .lock = v9fs_file_lock,
 855         .mmap = v9fs_file_mmap,
 856         .fsync = v9fs_file_fsync,
 857 };
 858
 859 const struct file_operations v9fs_cached_file_operations_dotl = {
 860         .llseek = generic_file_llseek,
 861         .read = v9fs_cached_file_read,
 862         .write = v9fs_cached_file_write,
 863         .read_iter = generic_file_read_iter,
 864         .write_iter = generic_file_write_iter,
 865         .open = v9fs_file_open,
 866         .release = v9fs_dir_release,
 867         .lock = v9fs_file_lock_dotl,
 868         .flock = v9fs_file_flock_dotl,
 869         .mmap = v9fs_file_mmap,
 870         .fsync = v9fs_file_fsync_dotl,
 871 };
 872
 873 const struct file_operations v9fs_file_operations = {
 874         .llseek = generic_file_llseek,
 875         .read = v9fs_file_read,
 876         .write = v9fs_file_write,
 877         .open = v9fs_file_open,
 878         .release = v9fs_dir_release,
 879         .lock = v9fs_file_lock,
 880         .mmap = generic_file_readonly_mmap,
 881         .fsync = v9fs_file_fsync,
 882 };
 883
 884 const struct file_operations v9fs_file_operations_dotl = {
 885         .llseek = generic_file_llseek,
 886         .read = v9fs_file_read,
 887         .write = v9fs_file_write,
 888         .open = v9fs_file_open,
 889         .release = v9fs_dir_release,
 890         .lock = v9fs_file_lock_dotl,
 891         .flock = v9fs_file_flock_dotl,
 892         .mmap = generic_file_readonly_mmap,
 893         .fsync = v9fs_file_fsync_dotl,
 894 };
 895
 896 const struct file_operations v9fs_mmap_file_operations = {
 897         .llseek = generic_file_llseek,
 898         .read = v9fs_mmap_file_read,
 899         .write = v9fs_mmap_file_write,
 900         .open = v9fs_file_open,
 901         .release = v9fs_dir_release,
 902         .lock = v9fs_file_lock,
 903         .mmap = v9fs_mmap_file_mmap,
 904         .fsync = v9fs_file_fsync,
 905 };
 906
 907 const struct file_operations v9fs_mmap_file_operations_dotl = {
 908         .llseek = generic_file_llseek,
 909         .read = v9fs_mmap_file_read,
 910         .write = v9fs_mmap_file_write,
 911         .open = v9fs_file_open,
 912         .release = v9fs_dir_release,
 913         .lock = v9fs_file_lock_dotl,
 914         .flock = v9fs_file_flock_dotl,
 915         .mmap = v9fs_mmap_file_mmap,
 916         .fsync = v9fs_file_fsync_dotl,
 917 };