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         .mmap           = nfs_file_mmap,
  68         .open           = nfs_file_open,
  69         .flush          = nfs_file_flush,
  70         .release        = nfs_file_release,
  71         .fsync          = nfs_fsync,
  72         .lock           = nfs_lock,
  73         .flock          = nfs_flock,
  74         .splice_read    = nfs_file_splice_read,
  75         .check_flags    = nfs_check_flags,
  76         .setlease       = nfs_setlease,
  77 };
  78
  79 const struct inode_operations nfs_file_inode_operations = {
  80         .permission     = nfs_permission,
  81         .getattr        = nfs_getattr,
  82         .setattr        = nfs_setattr,
  83 };
  84
  85 #ifdef CONFIG_NFS_V3
  86 const struct inode_operations nfs3_file_inode_operations = {
  87         .permission     = nfs_permission,
  88         .getattr        = nfs_getattr,
  89         .setattr        = nfs_setattr,
  90         .listxattr      = nfs3_listxattr,
  91         .getxattr       = nfs3_getxattr,
  92         .setxattr       = nfs3_setxattr,
  93         .removexattr    = nfs3_removexattr,
  94 };
  95 #endif  /* CONFIG_NFS_v3 */
  96
  97 /* Hack for future NFS swap support */
  98 #ifndef IS_SWAPFILE
  99 # define IS_SWAPFILE(inode)     (0)
 100 #endif
 101
 102 static int nfs_check_flags(int flags)
 103 {
 104         if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
 105                 return -EINVAL;
 106
 107         return 0;
 108 }
 109
 110 /*
 111  * Open file
 112  */
 113 static int
 114 nfs_file_open(struct inode *inode, struct file *filp)
 115 {
 116         int res;
 117
 118         res = nfs_check_flags(filp->f_flags);
 119         if (res)
 120                 return res;
 121
 122         nfs_inc_stats(inode, NFSIOS_VFSOPEN);
 123         lock_kernel();
 124         res = NFS_PROTO(inode)->file_open(inode, filp);
 125         unlock_kernel();
 126         return res;
 127 }
 128
 129 static int
 130 nfs_file_release(struct inode *inode, struct file *filp)
 131 {
 132         /* Ensure that dirty pages are flushed out with the right creds */
 133         if (filp->f_mode & FMODE_WRITE)
 134                 nfs_wb_all(filp->f_path.dentry->d_inode);
 135         nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
 136         return NFS_PROTO(inode)->file_release(inode, filp);
 137 }
 138
 139 /**
 140  * nfs_revalidate_size - Revalidate the file size
 141  * @inode - pointer to inode struct
 142  * @file - pointer to struct file
 143  *
 144  * Revalidates the file length. This is basically a wrapper around
 145  * nfs_revalidate_inode() that takes into account the fact that we may
 146  * have cached writes (in which case we don't care about the server's
 147  * idea of what the file length is), or O_DIRECT (in which case we
 148  * shouldn't trust the cache).
 149  */
 150 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
 151 {
 152         struct nfs_server *server = NFS_SERVER(inode);
 153         struct nfs_inode *nfsi = NFS_I(inode);
 154
 155         if (server->flags & NFS_MOUNT_NOAC)
 156                 goto force_reval;
 157         if (filp->f_flags & O_DIRECT)
 158                 goto force_reval;
 159         if (nfsi->npages != 0)
 160                 return 0;
 161         if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
 162                 return 0;
 163 force_reval:
 164         return __nfs_revalidate_inode(server, inode);
 165 }
 166
 167 static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
 168 {
 169         /* origin == SEEK_END => we must revalidate the cached file length */
 170         if (origin == SEEK_END) {
 171                 struct inode *inode = filp->f_mapping->host;
 172                 int retval = nfs_revalidate_file_size(inode, filp);
 173                 if (retval < 0)
 174                         return (loff_t)retval;
 175         }
 176         return remote_llseek(filp, offset, origin);
 177 }
 178
 179 /*
 180  * Helper for nfs_file_flush() and nfs_fsync()
 181  *
 182  * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
 183  * disk, but it retrieves and clears ctx->error after synching, despite
 184  * the two being set at the same time in nfs_context_set_write_error().
 185  * This is because the former is used to notify the _next_ call to
 186  * nfs_file_write() that a write error occured, and hence cause it to
 187  * fall back to doing a synchronous write.
 188  */
 189 static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
 190 {
 191         int have_error, status;
 192         int ret = 0;
 193
 194         have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 195         status = nfs_wb_all(inode);
 196         have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 197         if (have_error)
 198                 ret = xchg(&ctx->error, 0);
 199         if (!ret)
 200                 ret = status;
 201         return ret;
 202 }
 203
 204 /*
 205  * Flush all dirty pages, and check for write errors.
 206  *
 207  */
 208 static int
 209 nfs_file_flush(struct file *file, fl_owner_t id)
 210 {
 211         struct nfs_open_context *ctx = nfs_file_open_context(file);
 212         struct inode    *inode = file->f_path.dentry->d_inode;
 213         int             status;
 214
 215         dfprintk(VFS, "nfs: flush(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
 216
 217         if ((file->f_mode & FMODE_WRITE) == 0)
 218                 return 0;
 219         nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
 220
 221         /* Ensure that data+attribute caches are up to date after close() */
 222         status = nfs_do_fsync(ctx, inode);
 223         if (!status)
 224                 nfs_revalidate_inode(NFS_SERVER(inode), inode);
 225         return status;
 226 }
 227
 228 static ssize_t
 229 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
 230                 unsigned long nr_segs, loff_t pos)
 231 {
 232         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 233         struct inode * inode = dentry->d_inode;
 234         ssize_t result;
 235         size_t count = iov_length(iov, nr_segs);
 236
 237 #ifdef CONFIG_NFS_DIRECTIO
 238         if (iocb->ki_filp->f_flags & O_DIRECT)
 239                 return nfs_file_direct_read(iocb, iov, nr_segs, pos);
 240 #endif
 241
 242         dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
 243                 dentry->d_parent->d_name.name, dentry->d_name.name,
 244                 (unsigned long) count, (unsigned long) pos);
 245
 246         result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
 247         nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
 248         if (!result)
 249                 result = generic_file_aio_read(iocb, iov, nr_segs, pos);
 250         return result;
 251 }
 252
 253 static ssize_t
 254 nfs_file_splice_read(struct file *filp, loff_t *ppos,
 255                      struct pipe_inode_info *pipe, size_t count,
 256                      unsigned int flags)
 257 {
 258         struct dentry *dentry = filp->f_path.dentry;
 259         struct inode *inode = dentry->d_inode;
 260         ssize_t res;
 261
 262         dfprintk(VFS, "nfs: splice_read(%s/%s, %lu@%Lu)\n",
 263                 dentry->d_parent->d_name.name, dentry->d_name.name,
 264                 (unsigned long) count, (unsigned long long) *ppos);
 265
 266         res = nfs_revalidate_mapping(inode, filp->f_mapping);
 267         if (!res)
 268                 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
 269         return res;
 270 }
 271
 272 static int
 273 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
 274 {
 275         struct dentry *dentry = file->f_path.dentry;
 276         struct inode *inode = dentry->d_inode;
 277         int     status;
 278
 279         dfprintk(VFS, "nfs: mmap(%s/%s)\n",
 280                 dentry->d_parent->d_name.name, dentry->d_name.name);
 281
 282         status = nfs_revalidate_mapping(inode, file->f_mapping);
 283         if (!status) {
 284                 vma->vm_ops = &nfs_file_vm_ops;
 285                 vma->vm_flags |= VM_CAN_NONLINEAR;
 286                 file_accessed(file);
 287         }
 288         return status;
 289 }
 290
 291 /*
 292  * Flush any dirty pages for this process, and check for write errors.
 293  * The return status from this call provides a reliable indication of
 294  * whether any write errors occurred for this process.
 295  */
 296 static int
 297 nfs_fsync(struct file *file, struct dentry *dentry, int datasync)
 298 {
 299         struct nfs_open_context *ctx = nfs_file_open_context(file);
 300         struct inode *inode = dentry->d_inode;
 301
 302         dfprintk(VFS, "nfs: fsync(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
 303
 304         nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
 305         return nfs_do_fsync(ctx, inode);
 306 }
 307
 308 /*
 309  * This does the "real" work of the write. We must allocate and lock the
 310  * page to be sent back to the generic routine, which then copies the
 311  * data from user space.
 312  *
 313  * If the writer ends up delaying the write, the writer needs to
 314  * increment the page use counts until he is done with the page.
 315  */
 316 static int nfs_write_begin(struct file *file, struct address_space *mapping,
 317                         loff_t pos, unsigned len, unsigned flags,
 318                         struct page **pagep, void **fsdata)
 319 {
 320         int ret;
 321         pgoff_t index;
 322         struct page *page;
 323         index = pos >> PAGE_CACHE_SHIFT;
 324
 325         page = __grab_cache_page(mapping, index);
 326         if (!page)
 327                 return -ENOMEM;
 328         *pagep = page;
 329
 330         ret = nfs_flush_incompatible(file, page);
 331         if (ret) {
 332                 unlock_page(page);
 333                 page_cache_release(page);
 334         }
 335         return ret;
 336 }
 337
 338 static int nfs_write_end(struct file *file, struct address_space *mapping,
 339                         loff_t pos, unsigned len, unsigned copied,
 340                         struct page *page, void *fsdata)
 341 {
 342         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 343         int status;
 344
 345         lock_kernel();
 346         status = nfs_updatepage(file, page, offset, copied);
 347         unlock_kernel();
 348
 349         unlock_page(page);
 350         page_cache_release(page);
 351
 352         if (status < 0)
 353                 return status;
 354         return copied;
 355 }
 356
 357 static void nfs_invalidate_page(struct page *page, unsigned long offset)
 358 {
 359         if (offset != 0)
 360                 return;
 361         /* Cancel any unstarted writes on this page */
 362         nfs_wb_page_cancel(page->mapping->host, page);
 363 }
 364
 365 static int nfs_release_page(struct page *page, gfp_t gfp)
 366 {
 367         /* If PagePrivate() is set, then the page is not freeable */
 368         return 0;
 369 }
 370
 371 static int nfs_launder_page(struct page *page)
 372 {
 373         return nfs_wb_page(page->mapping->host, page);
 374 }
 375
 376 const struct address_space_operations nfs_file_aops = {
 377         .readpage = nfs_readpage,
 378         .readpages = nfs_readpages,
 379         .set_page_dirty = __set_page_dirty_nobuffers,
 380         .writepage = nfs_writepage,
 381         .writepages = nfs_writepages,
 382         .write_begin = nfs_write_begin,
 383         .write_end = nfs_write_end,
 384         .invalidatepage = nfs_invalidate_page,
 385         .releasepage = nfs_release_page,
 386 #ifdef CONFIG_NFS_DIRECTIO
 387         .direct_IO = nfs_direct_IO,
 388 #endif
 389         .launder_page = nfs_launder_page,
 390 };
 391
 392 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
 393 {
 394         struct file *filp = vma->vm_file;
 395         unsigned pagelen;
 396         int ret = -EINVAL;
 397         struct address_space *mapping;
 398
 399         lock_page(page);
 400         mapping = page->mapping;
 401         if (mapping != vma->vm_file->f_path.dentry->d_inode->i_mapping)
 402                 goto out_unlock;
 403
 404         ret = 0;
 405         pagelen = nfs_page_length(page);
 406         if (pagelen == 0)
 407                 goto out_unlock;
 408
 409         ret = nfs_flush_incompatible(filp, page);
 410         if (ret != 0)
 411                 goto out_unlock;
 412
 413         ret = nfs_updatepage(filp, page, 0, pagelen);
 414         if (ret == 0)
 415                 ret = pagelen;
 416 out_unlock:
 417         unlock_page(page);
 418         return ret;
 419 }
 420
 421 static struct vm_operations_struct nfs_file_vm_ops = {
 422         .fault = filemap_fault,
 423         .page_mkwrite = nfs_vm_page_mkwrite,
 424 };
 425
 426 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
 427 {
 428         struct nfs_open_context *ctx;
 429
 430         if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
 431                 return 1;
 432         ctx = nfs_file_open_context(filp);
 433         if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
 434                 return 1;
 435         return 0;
 436 }
 437
 438 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
 439                                 unsigned long nr_segs, loff_t pos)
 440 {
 441         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 442         struct inode * inode = dentry->d_inode;
 443         ssize_t result;
 444         size_t count = iov_length(iov, nr_segs);
 445
 446 #ifdef CONFIG_NFS_DIRECTIO
 447         if (iocb->ki_filp->f_flags & O_DIRECT)
 448                 return nfs_file_direct_write(iocb, iov, nr_segs, pos);
 449 #endif
 450
 451         dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%Ld)\n",
 452                 dentry->d_parent->d_name.name, dentry->d_name.name,
 453                 inode->i_ino, (unsigned long) count, (long long) pos);
 454
 455         result = -EBUSY;
 456         if (IS_SWAPFILE(inode))
 457                 goto out_swapfile;
 458         /*
 459          * O_APPEND implies that we must revalidate the file length.
 460          */
 461         if (iocb->ki_filp->f_flags & O_APPEND) {
 462                 result = nfs_revalidate_file_size(inode, iocb->ki_filp);
 463                 if (result)
 464                         goto out;
 465         }
 466
 467         result = count;
 468         if (!count)
 469                 goto out;
 470
 471         nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 472         result = generic_file_aio_write(iocb, iov, nr_segs, pos);
 473         /* Return error values for O_SYNC and IS_SYNC() */
 474         if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
 475                 int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
 476                 if (err < 0)
 477                         result = err;
 478         }
 479 out:
 480         return result;
 481
 482 out_swapfile:
 483         printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
 484         goto out;
 485 }
 486
 487 static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
 488 {
 489         struct inode *inode = filp->f_mapping->host;
 490         int status = 0;
 491
 492         lock_kernel();
 493         /* Try local locking first */
 494         posix_test_lock(filp, fl);
 495         if (fl->fl_type != F_UNLCK) {
 496                 /* found a conflict */
 497                 goto out;
 498         }
 499
 500         if (nfs_have_delegation(inode, FMODE_READ))
 501                 goto out_noconflict;
 502
 503         if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
 504                 goto out_noconflict;
 505
 506         status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 507 out:
 508         unlock_kernel();
 509         return status;
 510 out_noconflict:
 511         fl->fl_type = F_UNLCK;
 512         goto out;
 513 }
 514
 515 static int do_vfs_lock(struct file *file, struct file_lock *fl)
 516 {
 517         int res = 0;
 518         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 519                 case FL_POSIX:
 520                         res = posix_lock_file_wait(file, fl);
 521                         break;
 522                 case FL_FLOCK:
 523                         res = flock_lock_file_wait(file, fl);
 524                         break;
 525                 default:
 526                         BUG();
 527         }
 528         if (res < 0)
 529                 dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
 530                         " - error %d!\n",
 531                                 __FUNCTION__, res);
 532         return res;
 533 }
 534
 535 static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
 536 {
 537         struct inode *inode = filp->f_mapping->host;
 538         int status;
 539
 540         /*
 541          * Flush all pending writes before doing anything
 542          * with locks..
 543          */
 544         nfs_sync_mapping(filp->f_mapping);
 545
 546         /* NOTE: special case
 547          *      If we're signalled while cleaning up locks on process exit, we
 548          *      still need to complete the unlock.
 549          */
 550         lock_kernel();
 551         /* Use local locking if mounted with "-onolock" */
 552         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 553                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 554         else
 555                 status = do_vfs_lock(filp, fl);
 556         unlock_kernel();
 557         return status;
 558 }
 559
 560 static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
 561 {
 562         struct inode *inode = filp->f_mapping->host;
 563         int status;
 564
 565         /*
 566          * Flush all pending writes before doing anything
 567          * with locks..
 568          */
 569         status = nfs_sync_mapping(filp->f_mapping);
 570         if (status != 0)
 571                 goto out;
 572
 573         lock_kernel();
 574         /* Use local locking if mounted with "-onolock" */
 575         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)) {
 576                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 577                 /* If we were signalled we still need to ensure that
 578                  * we clean up any state on the server. We therefore
 579                  * record the lock call as having succeeded in order to
 580                  * ensure that locks_remove_posix() cleans it out when
 581                  * the process exits.
 582                  */
 583                 if (status == -EINTR || status == -ERESTARTSYS)
 584                         do_vfs_lock(filp, fl);
 585         } else
 586                 status = do_vfs_lock(filp, fl);
 587         unlock_kernel();
 588         if (status < 0)
 589                 goto out;
 590         /*
 591          * Make sure we clear the cache whenever we try to get the lock.
 592          * This makes locking act as a cache coherency point.
 593          */
 594         nfs_sync_mapping(filp->f_mapping);
 595         nfs_zap_caches(inode);
 596 out:
 597         return status;
 598 }
 599
 600 /*
 601  * Lock a (portion of) a file
 602  */
 603 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
 604 {
 605         struct inode * inode = filp->f_mapping->host;
 606
 607         dprintk("NFS: nfs_lock(f=%s/%ld, t=%x, fl=%x, r=%Ld:%Ld)\n",
 608                         inode->i_sb->s_id, inode->i_ino,
 609                         fl->fl_type, fl->fl_flags,
 610                         (long long)fl->fl_start, (long long)fl->fl_end);
 611         nfs_inc_stats(inode, NFSIOS_VFSLOCK);
 612
 613         /* No mandatory locks over NFS */
 614         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 615                 return -ENOLCK;
 616
 617         if (IS_GETLK(cmd))
 618                 return do_getlk(filp, cmd, fl);
 619         if (fl->fl_type == F_UNLCK)
 620                 return do_unlk(filp, cmd, fl);
 621         return do_setlk(filp, cmd, fl);
 622 }
 623
 624 /*
 625  * Lock a (portion of) a file
 626  */
 627 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
 628 {
 629         dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
 630                         filp->f_path.dentry->d_inode->i_sb->s_id,
 631                         filp->f_path.dentry->d_inode->i_ino,
 632                         fl->fl_type, fl->fl_flags);
 633
 634         /*
 635          * No BSD flocks over NFS allowed.
 636          * Note: we could try to fake a POSIX lock request here by
 637          * using ((u32) filp | 0x80000000) or some such as the pid.
 638          * Not sure whether that would be unique, though, or whether
 639          * that would break in other places.
 640          */
 641         if (!(fl->fl_flags & FL_FLOCK))
 642                 return -ENOLCK;
 643
 644         /* We're simulating flock() locks using posix locks on the server */
 645         fl->fl_owner = (fl_owner_t)filp;
 646         fl->fl_start = 0;
 647         fl->fl_end = OFFSET_MAX;
 648
 649         if (fl->fl_type == F_UNLCK)
 650                 return do_unlk(filp, cmd, fl);
 651         return do_setlk(filp, cmd, fl);
 652 }
 653
 654 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
 655 {
 656         /*
 657          * There is no protocol support for leases, so we have no way
 658          * to implement them correctly in the face of opens by other
 659          * clients.
 660          */
 661         return -EINVAL;
 662 }