fs/nfs/file.c

   1 /*
   2  *  linux/fs/nfs/file.c
   3  *
   4  *  Copyright (C) 1992  Rick Sladkey
   5  *
   6  *  Changes Copyright (C) 1994 by Florian La Roche
   7  *   - Do not copy data too often around in the kernel.
   8  *   - In nfs_file_read the return value of kmalloc wasn't checked.
   9  *   - Put in a better version of read look-ahead buffering. Original idea
  10  *     and implementation by Wai S Kok elekokws@ee.nus.sg.
  11  *
  12  *  Expire cache on write to a file by Wai S Kok (Oct 1994).
  13  *
  14  *  Total rewrite of read side for new NFS buffer cache.. Linus.
  15  *
  16  *  nfs regular file handling functions
  17  */
  18
  19 #include <linux/time.h>
  20 #include <linux/kernel.h>
  21 #include <linux/errno.h>
  22 #include <linux/fcntl.h>
  23 #include <linux/stat.h>
  24 #include <linux/nfs_fs.h>
  25 #include <linux/nfs_mount.h>
  26 #include <linux/mm.h>
  27 #include <linux/slab.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/smp_lock.h>
  30 #include <linux/aio.h>
  31
  32 #include <asm/uaccess.h>
  33 #include <asm/system.h>
  34
  35 #include "delegation.h"
  36 #include "internal.h"
  37 #include "iostat.h"
  38
  39 #define NFSDBG_FACILITY         NFSDBG_FILE
  40
  41 static int nfs_file_open(struct inode *, struct file *);
  42 static int nfs_file_release(struct inode *, struct file *);
  43 static loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
  44 static int  nfs_file_mmap(struct file *, struct vm_area_struct *);
  45 static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos,
  46                                         struct pipe_inode_info *pipe,
  47                                         size_t count, unsigned int flags);
  48 static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
  49                                 unsigned long nr_segs, loff_t pos);
  50 static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
  51                                 unsigned long nr_segs, loff_t pos);
  52 static int  nfs_file_flush(struct file *, fl_owner_t id);
  53 static int  nfs_fsync(struct file *, struct dentry *dentry, int datasync);
  54 static int nfs_check_flags(int flags);
  55 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
  56 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
  57 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);
  58
  59 static struct vm_operations_struct nfs_file_vm_ops;
  60
  61 const struct file_operations nfs_file_operations = {
  62         .llseek         = nfs_file_llseek,
  63         .read           = do_sync_read,
  64         .write          = do_sync_write,
  65         .aio_read       = nfs_file_read,
  66         .aio_write      = nfs_file_write,
  67 #ifdef CONFIG_MMU
  68         .mmap           = nfs_file_mmap,
  69 #else
  70         .mmap           = generic_file_mmap,
  71 #endif
  72         .open           = nfs_file_open,
  73         .flush          = nfs_file_flush,
  74         .release        = nfs_file_release,
  75         .fsync          = nfs_fsync,
  76         .lock           = nfs_lock,
  77         .flock          = nfs_flock,
  78         .splice_read    = nfs_file_splice_read,
  79         .check_flags    = nfs_check_flags,
  80         .setlease       = nfs_setlease,
  81 };
  82
  83 const struct inode_operations nfs_file_inode_operations = {
  84         .permission     = nfs_permission,
  85         .getattr        = nfs_getattr,
  86         .setattr        = nfs_setattr,
  87 };
  88
  89 #ifdef CONFIG_NFS_V3
  90 const struct inode_operations nfs3_file_inode_operations = {
  91         .permission     = nfs_permission,
  92         .getattr        = nfs_getattr,
  93         .setattr        = nfs_setattr,
  94         .listxattr      = nfs3_listxattr,
  95         .getxattr       = nfs3_getxattr,
  96         .setxattr       = nfs3_setxattr,
  97         .removexattr    = nfs3_removexattr,
  98 };
  99 #endif  /* CONFIG_NFS_v3 */
 100
 101 /* Hack for future NFS swap support */
 102 #ifndef IS_SWAPFILE
 103 # define IS_SWAPFILE(inode)     (0)
 104 #endif
 105
 106 static int nfs_check_flags(int flags)
 107 {
 108         if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
 109                 return -EINVAL;
 110
 111         return 0;
 112 }
 113
 114 /*
 115  * Open file
 116  */
 117 static int
 118 nfs_file_open(struct inode *inode, struct file *filp)
 119 {
 120         int res;
 121
 122         res = nfs_check_flags(filp->f_flags);
 123         if (res)
 124                 return res;
 125
 126         nfs_inc_stats(inode, NFSIOS_VFSOPEN);
 127         lock_kernel();
 128         res = NFS_PROTO(inode)->file_open(inode, filp);
 129         unlock_kernel();
 130         return res;
 131 }
 132
 133 static int
 134 nfs_file_release(struct inode *inode, struct file *filp)
 135 {
 136         /* Ensure that dirty pages are flushed out with the right creds */
 137         if (filp->f_mode & FMODE_WRITE)
 138                 nfs_wb_all(filp->f_path.dentry->d_inode);
 139         nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
 140         return NFS_PROTO(inode)->file_release(inode, filp);
 141 }
 142
 143 /**
 144  * nfs_revalidate_size - Revalidate the file size
 145  * @inode - pointer to inode struct
 146  * @file - pointer to struct file
 147  *
 148  * Revalidates the file length. This is basically a wrapper around
 149  * nfs_revalidate_inode() that takes into account the fact that we may
 150  * have cached writes (in which case we don't care about the server's
 151  * idea of what the file length is), or O_DIRECT (in which case we
 152  * shouldn't trust the cache).
 153  */
 154 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
 155 {
 156         struct nfs_server *server = NFS_SERVER(inode);
 157         struct nfs_inode *nfsi = NFS_I(inode);
 158
 159         if (server->flags & NFS_MOUNT_NOAC)
 160                 goto force_reval;
 161         if (filp->f_flags & O_DIRECT)
 162                 goto force_reval;
 163         if (nfsi->npages != 0)
 164                 return 0;
 165         if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
 166                 return 0;
 167 force_reval:
 168         return __nfs_revalidate_inode(server, inode);
 169 }
 170
 171 static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
 172 {
 173         loff_t loff;
 174         /* origin == SEEK_END => we must revalidate the cached file length */
 175         if (origin == SEEK_END) {
 176                 struct inode *inode = filp->f_mapping->host;
 177                 int retval = nfs_revalidate_file_size(inode, filp);
 178                 if (retval < 0)
 179                         return (loff_t)retval;
 180         }
 181         lock_kernel();  /* BKL needed? */
 182         loff = generic_file_llseek_unlocked(filp, offset, origin);
 183         unlock_kernel();
 184         return loff;
 185 }
 186
 187 /*
 188  * Helper for nfs_file_flush() and nfs_fsync()
 189  *
 190  * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
 191  * disk, but it retrieves and clears ctx->error after synching, despite
 192  * the two being set at the same time in nfs_context_set_write_error().
 193  * This is because the former is used to notify the _next_ call to
 194  * nfs_file_write() that a write error occured, and hence cause it to
 195  * fall back to doing a synchronous write.
 196  */
 197 static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
 198 {
 199         int have_error, status;
 200         int ret = 0;
 201
 202         have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 203         status = nfs_wb_all(inode);
 204         have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 205         if (have_error)
 206                 ret = xchg(&ctx->error, 0);
 207         if (!ret)
 208                 ret = status;
 209         return ret;
 210 }
 211
 212 /*
 213  * Flush all dirty pages, and check for write errors.
 214  *
 215  */
 216 static int
 217 nfs_file_flush(struct file *file, fl_owner_t id)
 218 {
 219         struct nfs_open_context *ctx = nfs_file_open_context(file);
 220         struct inode    *inode = file->f_path.dentry->d_inode;
 221         int             status;
 222
 223         dfprintk(VFS, "nfs: flush(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
 224
 225         if ((file->f_mode & FMODE_WRITE) == 0)
 226                 return 0;
 227         nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
 228
 229         /* Ensure that data+attribute caches are up to date after close() */
 230         status = nfs_do_fsync(ctx, inode);
 231         if (!status)
 232                 nfs_revalidate_inode(NFS_SERVER(inode), inode);
 233         return status;
 234 }
 235
 236 static ssize_t
 237 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
 238                 unsigned long nr_segs, loff_t pos)
 239 {
 240         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 241         struct inode * inode = dentry->d_inode;
 242         ssize_t result;
 243         size_t count = iov_length(iov, nr_segs);
 244
 245         if (iocb->ki_filp->f_flags & O_DIRECT)
 246                 return nfs_file_direct_read(iocb, iov, nr_segs, pos);
 247
 248         dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
 249                 dentry->d_parent->d_name.name, dentry->d_name.name,
 250                 (unsigned long) count, (unsigned long) pos);
 251
 252         result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
 253         nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
 254         if (!result)
 255                 result = generic_file_aio_read(iocb, iov, nr_segs, pos);
 256         return result;
 257 }
 258
 259 static ssize_t
 260 nfs_file_splice_read(struct file *filp, loff_t *ppos,
 261                      struct pipe_inode_info *pipe, size_t count,
 262                      unsigned int flags)
 263 {
 264         struct dentry *dentry = filp->f_path.dentry;
 265         struct inode *inode = dentry->d_inode;
 266         ssize_t res;
 267
 268         dfprintk(VFS, "nfs: splice_read(%s/%s, %lu@%Lu)\n",
 269                 dentry->d_parent->d_name.name, dentry->d_name.name,
 270                 (unsigned long) count, (unsigned long long) *ppos);
 271
 272         res = nfs_revalidate_mapping(inode, filp->f_mapping);
 273         if (!res)
 274                 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
 275         return res;
 276 }
 277
 278 static int
 279 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
 280 {
 281         struct dentry *dentry = file->f_path.dentry;
 282         struct inode *inode = dentry->d_inode;
 283         int     status;
 284
 285         dfprintk(VFS, "nfs: mmap(%s/%s)\n",
 286                 dentry->d_parent->d_name.name, dentry->d_name.name);
 287
 288         status = nfs_revalidate_mapping(inode, file->f_mapping);
 289         if (!status) {
 290                 vma->vm_ops = &nfs_file_vm_ops;
 291                 vma->vm_flags |= VM_CAN_NONLINEAR;
 292                 file_accessed(file);
 293         }
 294         return status;
 295 }
 296
 297 /*
 298  * Flush any dirty pages for this process, and check for write errors.
 299  * The return status from this call provides a reliable indication of
 300  * whether any write errors occurred for this process.
 301  */
 302 static int
 303 nfs_fsync(struct file *file, struct dentry *dentry, int datasync)
 304 {
 305         struct nfs_open_context *ctx = nfs_file_open_context(file);
 306         struct inode *inode = dentry->d_inode;
 307
 308         dfprintk(VFS, "nfs: fsync(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
 309
 310         nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
 311         return nfs_do_fsync(ctx, inode);
 312 }
 313
 314 /*
 315  * This does the "real" work of the write. We must allocate and lock the
 316  * page to be sent back to the generic routine, which then copies the
 317  * data from user space.
 318  *
 319  * If the writer ends up delaying the write, the writer needs to
 320  * increment the page use counts until he is done with the page.
 321  */
 322 static int nfs_write_begin(struct file *file, struct address_space *mapping,
 323                         loff_t pos, unsigned len, unsigned flags,
 324                         struct page **pagep, void **fsdata)
 325 {
 326         int ret;
 327         pgoff_t index;
 328         struct page *page;
 329         index = pos >> PAGE_CACHE_SHIFT;
 330
 331         page = __grab_cache_page(mapping, index);
 332         if (!page)
 333                 return -ENOMEM;
 334         *pagep = page;
 335
 336         ret = nfs_flush_incompatible(file, page);
 337         if (ret) {
 338                 unlock_page(page);
 339                 page_cache_release(page);
 340         }
 341         return ret;
 342 }
 343
 344 static int nfs_write_end(struct file *file, struct address_space *mapping,
 345                         loff_t pos, unsigned len, unsigned copied,
 346                         struct page *page, void *fsdata)
 347 {
 348         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 349         int status;
 350
 351         lock_kernel();
 352         status = nfs_updatepage(file, page, offset, copied);
 353         unlock_kernel();
 354
 355         unlock_page(page);
 356         page_cache_release(page);
 357
 358         if (status < 0)
 359                 return status;
 360         return copied;
 361 }
 362
 363 static void nfs_invalidate_page(struct page *page, unsigned long offset)
 364 {
 365         if (offset != 0)
 366                 return;
 367         /* Cancel any unstarted writes on this page */
 368         nfs_wb_page_cancel(page->mapping->host, page);
 369 }
 370
 371 static int nfs_release_page(struct page *page, gfp_t gfp)
 372 {
 373         /* If PagePrivate() is set, then the page is not freeable */
 374         return 0;
 375 }
 376
 377 static int nfs_launder_page(struct page *page)
 378 {
 379         return nfs_wb_page(page->mapping->host, page);
 380 }
 381
 382 const struct address_space_operations nfs_file_aops = {
 383         .readpage = nfs_readpage,
 384         .readpages = nfs_readpages,
 385         .set_page_dirty = __set_page_dirty_nobuffers,
 386         .writepage = nfs_writepage,
 387         .writepages = nfs_writepages,
 388         .write_begin = nfs_write_begin,
 389         .write_end = nfs_write_end,
 390         .invalidatepage = nfs_invalidate_page,
 391         .releasepage = nfs_release_page,
 392         .direct_IO = nfs_direct_IO,
 393         .launder_page = nfs_launder_page,
 394 };
 395
 396 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
 397 {
 398         struct file *filp = vma->vm_file;
 399         unsigned pagelen;
 400         int ret = -EINVAL;
 401         struct address_space *mapping;
 402
 403         lock_page(page);
 404         mapping = page->mapping;
 405         if (mapping != vma->vm_file->f_path.dentry->d_inode->i_mapping)
 406                 goto out_unlock;
 407
 408         ret = 0;
 409         pagelen = nfs_page_length(page);
 410         if (pagelen == 0)
 411                 goto out_unlock;
 412
 413         ret = nfs_flush_incompatible(filp, page);
 414         if (ret != 0)
 415                 goto out_unlock;
 416
 417         ret = nfs_updatepage(filp, page, 0, pagelen);
 418         if (ret == 0)
 419                 ret = pagelen;
 420 out_unlock:
 421         unlock_page(page);
 422         return ret;
 423 }
 424
 425 static struct vm_operations_struct nfs_file_vm_ops = {
 426         .fault = filemap_fault,
 427         .page_mkwrite = nfs_vm_page_mkwrite,
 428 };
 429
 430 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
 431 {
 432         struct nfs_open_context *ctx;
 433
 434         if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
 435                 return 1;
 436         ctx = nfs_file_open_context(filp);
 437         if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
 438                 return 1;
 439         return 0;
 440 }
 441
 442 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
 443                                 unsigned long nr_segs, loff_t pos)
 444 {
 445         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 446         struct inode * inode = dentry->d_inode;
 447         ssize_t result;
 448         size_t count = iov_length(iov, nr_segs);
 449
 450         if (iocb->ki_filp->f_flags & O_DIRECT)
 451                 return nfs_file_direct_write(iocb, iov, nr_segs, pos);
 452
 453         dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%Ld)\n",
 454                 dentry->d_parent->d_name.name, dentry->d_name.name,
 455                 inode->i_ino, (unsigned long) count, (long long) pos);
 456
 457         result = -EBUSY;
 458         if (IS_SWAPFILE(inode))
 459                 goto out_swapfile;
 460         /*
 461          * O_APPEND implies that we must revalidate the file length.
 462          */
 463         if (iocb->ki_filp->f_flags & O_APPEND) {
 464                 result = nfs_revalidate_file_size(inode, iocb->ki_filp);
 465                 if (result)
 466                         goto out;
 467         }
 468
 469         result = count;
 470         if (!count)
 471                 goto out;
 472
 473         nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 474         result = generic_file_aio_write(iocb, iov, nr_segs, pos);
 475         /* Return error values for O_SYNC and IS_SYNC() */
 476         if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
 477                 int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
 478                 if (err < 0)
 479                         result = err;
 480         }
 481 out:
 482         return result;
 483
 484 out_swapfile:
 485         printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
 486         goto out;
 487 }
 488
 489 static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
 490 {
 491         struct inode *inode = filp->f_mapping->host;
 492         int status = 0;
 493
 494         lock_kernel();
 495         /* Try local locking first */
 496         posix_test_lock(filp, fl);
 497         if (fl->fl_type != F_UNLCK) {
 498                 /* found a conflict */
 499                 goto out;
 500         }
 501
 502         if (nfs_have_delegation(inode, FMODE_READ))
 503                 goto out_noconflict;
 504
 505         if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
 506                 goto out_noconflict;
 507
 508         status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 509 out:
 510         unlock_kernel();
 511         return status;
 512 out_noconflict:
 513         fl->fl_type = F_UNLCK;
 514         goto out;
 515 }
 516
 517 static int do_vfs_lock(struct file *file, struct file_lock *fl)
 518 {
 519         int res = 0;
 520         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 521                 case FL_POSIX:
 522                         res = posix_lock_file_wait(file, fl);
 523                         break;
 524                 case FL_FLOCK:
 525                         res = flock_lock_file_wait(file, fl);
 526                         break;
 527                 default:
 528                         BUG();
 529         }
 530         if (res < 0)
 531                 dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
 532                         " - error %d!\n",
 533                                 __FUNCTION__, res);
 534         return res;
 535 }
 536
 537 static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
 538 {
 539         struct inode *inode = filp->f_mapping->host;
 540         int status;
 541
 542         /*
 543          * Flush all pending writes before doing anything
 544          * with locks..
 545          */
 546         nfs_sync_mapping(filp->f_mapping);
 547
 548         /* NOTE: special case
 549          *      If we're signalled while cleaning up locks on process exit, we
 550          *      still need to complete the unlock.
 551          */
 552         lock_kernel();
 553         /* Use local locking if mounted with "-onolock" */
 554         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 555                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 556         else
 557                 status = do_vfs_lock(filp, fl);
 558         unlock_kernel();
 559         return status;
 560 }
 561
 562 static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
 563 {
 564         struct inode *inode = filp->f_mapping->host;
 565         int status;
 566
 567         /*
 568          * Flush all pending writes before doing anything
 569          * with locks..
 570          */
 571         status = nfs_sync_mapping(filp->f_mapping);
 572         if (status != 0)
 573                 goto out;
 574
 575         lock_kernel();
 576         /* Use local locking if mounted with "-onolock" */
 577         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 578                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 579         else
 580                 status = do_vfs_lock(filp, fl);
 581         unlock_kernel();
 582         if (status < 0)
 583                 goto out;
 584         /*
 585          * Make sure we clear the cache whenever we try to get the lock.
 586          * This makes locking act as a cache coherency point.
 587          */
 588         nfs_sync_mapping(filp->f_mapping);
 589         nfs_zap_caches(inode);
 590 out:
 591         return status;
 592 }
 593
 594 /*
 595  * Lock a (portion of) a file
 596  */
 597 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
 598 {
 599         struct inode * inode = filp->f_mapping->host;
 600
 601         dprintk("NFS: nfs_lock(f=%s/%ld, t=%x, fl=%x, r=%Ld:%Ld)\n",
 602                         inode->i_sb->s_id, inode->i_ino,
 603                         fl->fl_type, fl->fl_flags,
 604                         (long long)fl->fl_start, (long long)fl->fl_end);
 605         nfs_inc_stats(inode, NFSIOS_VFSLOCK);
 606
 607         /* No mandatory locks over NFS */
 608         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 609                 return -ENOLCK;
 610
 611         if (IS_GETLK(cmd))
 612                 return do_getlk(filp, cmd, fl);
 613         if (fl->fl_type == F_UNLCK)
 614                 return do_unlk(filp, cmd, fl);
 615         return do_setlk(filp, cmd, fl);
 616 }
 617
 618 /*
 619  * Lock a (portion of) a file
 620  */
 621 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
 622 {
 623         dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
 624                         filp->f_path.dentry->d_inode->i_sb->s_id,
 625                         filp->f_path.dentry->d_inode->i_ino,
 626                         fl->fl_type, fl->fl_flags);
 627
 628         /*
 629          * No BSD flocks over NFS allowed.
 630          * Note: we could try to fake a POSIX lock request here by
 631          * using ((u32) filp | 0x80000000) or some such as the pid.
 632          * Not sure whether that would be unique, though, or whether
 633          * that would break in other places.
 634          */
 635         if (!(fl->fl_flags & FL_FLOCK))
 636                 return -ENOLCK;
 637
 638         /* We're simulating flock() locks using posix locks on the server */
 639         fl->fl_owner = (fl_owner_t)filp;
 640         fl->fl_start = 0;
 641         fl->fl_end = OFFSET_MAX;
 642
 643         if (fl->fl_type == F_UNLCK)
 644                 return do_unlk(filp, cmd, fl);
 645         return do_setlk(filp, cmd, fl);
 646 }
 647
 648 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
 649 {
 650         /*
 651          * There is no protocol support for leases, so we have no way
 652          * to implement them correctly in the face of opens by other
 653          * clients.
 654          */
 655         return -EINVAL;
 656 }