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_file_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_file_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         /* origin == SEEK_END => we must revalidate the cached file length */
 174         if (origin == SEEK_END) {
 175                 struct inode *inode = filp->f_mapping->host;
 176                 int retval = nfs_revalidate_file_size(inode, filp);
 177                 if (retval < 0)
 178                         return (loff_t)retval;
 179         }
 180         return remote_llseek(filp, offset, origin);
 181 }
 182
 183 /*
 184  * Helper for nfs_file_flush() and nfs_file_fsync()
 185  *
 186  * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
 187  * disk, but it retrieves and clears ctx->error after synching, despite
 188  * the two being set at the same time in nfs_context_set_write_error().
 189  * This is because the former is used to notify the _next_ call to
 190  * nfs_file_write() that a write error occured, and hence cause it to
 191  * fall back to doing a synchronous write.
 192  */
 193 static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
 194 {
 195         int have_error, status;
 196         int ret = 0;
 197
 198         have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 199         status = nfs_wb_all(inode);
 200         have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 201         if (have_error)
 202                 ret = xchg(&ctx->error, 0);
 203         if (!ret)
 204                 ret = status;
 205         return ret;
 206 }
 207
 208 /*
 209  * Flush all dirty pages, and check for write errors.
 210  *
 211  */
 212 static int
 213 nfs_file_flush(struct file *file, fl_owner_t id)
 214 {
 215         struct nfs_open_context *ctx = nfs_file_open_context(file);
 216         struct inode    *inode = file->f_path.dentry->d_inode;
 217         int             status;
 218
 219         dfprintk(VFS, "nfs: flush(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
 220
 221         if ((file->f_mode & FMODE_WRITE) == 0)
 222                 return 0;
 223         nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
 224
 225         /* Ensure that data+attribute caches are up to date after close() */
 226         status = nfs_do_fsync(ctx, inode);
 227         if (!status)
 228                 nfs_revalidate_inode(NFS_SERVER(inode), inode);
 229         return status;
 230 }
 231
 232 static ssize_t
 233 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
 234                 unsigned long nr_segs, loff_t pos)
 235 {
 236         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 237         struct inode * inode = dentry->d_inode;
 238         ssize_t result;
 239         size_t count = iov_length(iov, nr_segs);
 240
 241         if (iocb->ki_filp->f_flags & O_DIRECT)
 242                 return nfs_file_direct_read(iocb, iov, nr_segs, pos);
 243
 244         dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
 245                 dentry->d_parent->d_name.name, dentry->d_name.name,
 246                 (unsigned long) count, (unsigned long) pos);
 247
 248         result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
 249         nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
 250         if (!result)
 251                 result = generic_file_aio_read(iocb, iov, nr_segs, pos);
 252         return result;
 253 }
 254
 255 static ssize_t
 256 nfs_file_splice_read(struct file *filp, loff_t *ppos,
 257                      struct pipe_inode_info *pipe, size_t count,
 258                      unsigned int flags)
 259 {
 260         struct dentry *dentry = filp->f_path.dentry;
 261         struct inode *inode = dentry->d_inode;
 262         ssize_t res;
 263
 264         dfprintk(VFS, "nfs: splice_read(%s/%s, %lu@%Lu)\n",
 265                 dentry->d_parent->d_name.name, dentry->d_name.name,
 266                 (unsigned long) count, (unsigned long long) *ppos);
 267
 268         res = nfs_revalidate_mapping(inode, filp->f_mapping);
 269         if (!res)
 270                 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
 271         return res;
 272 }
 273
 274 static int
 275 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
 276 {
 277         struct dentry *dentry = file->f_path.dentry;
 278         struct inode *inode = dentry->d_inode;
 279         int     status;
 280
 281         dfprintk(VFS, "nfs: mmap(%s/%s)\n",
 282                 dentry->d_parent->d_name.name, dentry->d_name.name);
 283
 284         status = nfs_revalidate_mapping(inode, file->f_mapping);
 285         if (!status) {
 286                 vma->vm_ops = &nfs_file_vm_ops;
 287                 vma->vm_flags |= VM_CAN_NONLINEAR;
 288                 file_accessed(file);
 289         }
 290         return status;
 291 }
 292
 293 /*
 294  * Flush any dirty pages for this process, and check for write errors.
 295  * The return status from this call provides a reliable indication of
 296  * whether any write errors occurred for this process.
 297  */
 298 static int
 299 nfs_file_fsync(struct file *file, struct dentry *dentry, int datasync)
 300 {
 301         struct nfs_open_context *ctx = nfs_file_open_context(file);
 302         struct inode *inode = dentry->d_inode;
 303
 304         dfprintk(VFS, "NFS: fsync file(%s/%s) datasync %d\n",
 305                         dentry->d_parent->d_name.name, dentry->d_name.name,
 306                         datasync);
 307
 308         nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
 309         return nfs_do_fsync(ctx, inode);
 310 }
 311
 312 /*
 313  * This does the "real" work of the write. We must allocate and lock the
 314  * page to be sent back to the generic routine, which then copies the
 315  * data from user space.
 316  *
 317  * If the writer ends up delaying the write, the writer needs to
 318  * increment the page use counts until he is done with the page.
 319  */
 320 static int nfs_write_begin(struct file *file, struct address_space *mapping,
 321                         loff_t pos, unsigned len, unsigned flags,
 322                         struct page **pagep, void **fsdata)
 323 {
 324         int ret;
 325         pgoff_t index;
 326         struct page *page;
 327         index = pos >> PAGE_CACHE_SHIFT;
 328
 329         page = __grab_cache_page(mapping, index);
 330         if (!page)
 331                 return -ENOMEM;
 332         *pagep = page;
 333
 334         ret = nfs_flush_incompatible(file, page);
 335         if (ret) {
 336                 unlock_page(page);
 337                 page_cache_release(page);
 338         }
 339         return ret;
 340 }
 341
 342 static int nfs_write_end(struct file *file, struct address_space *mapping,
 343                         loff_t pos, unsigned len, unsigned copied,
 344                         struct page *page, void *fsdata)
 345 {
 346         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 347         int status;
 348
 349         /*
 350          * Zero any uninitialised parts of the page, and then mark the page
 351          * as up to date if it turns out that we're extending the file.
 352          */
 353         if (!PageUptodate(page)) {
 354                 unsigned pglen = nfs_page_length(page);
 355                 unsigned end = offset + len;
 356
 357                 if (pglen == 0) {
 358                         zero_user_segments(page, 0, offset,
 359                                         end, PAGE_CACHE_SIZE);
 360                         SetPageUptodate(page);
 361                 } else if (end >= pglen) {
 362                         zero_user_segment(page, end, PAGE_CACHE_SIZE);
 363                         if (offset == 0)
 364                                 SetPageUptodate(page);
 365                 } else
 366                         zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
 367         }
 368
 369         lock_kernel();
 370         status = nfs_updatepage(file, page, offset, copied);
 371         unlock_kernel();
 372
 373         unlock_page(page);
 374         page_cache_release(page);
 375
 376         if (status < 0)
 377                 return status;
 378         return copied;
 379 }
 380
 381 static void nfs_invalidate_page(struct page *page, unsigned long offset)
 382 {
 383         if (offset != 0)
 384                 return;
 385         /* Cancel any unstarted writes on this page */
 386         nfs_wb_page_cancel(page->mapping->host, page);
 387 }
 388
 389 static int nfs_release_page(struct page *page, gfp_t gfp)
 390 {
 391         /* If PagePrivate() is set, then the page is not freeable */
 392         return 0;
 393 }
 394
 395 static int nfs_launder_page(struct page *page)
 396 {
 397         return nfs_wb_page(page->mapping->host, page);
 398 }
 399
 400 const struct address_space_operations nfs_file_aops = {
 401         .readpage = nfs_readpage,
 402         .readpages = nfs_readpages,
 403         .set_page_dirty = __set_page_dirty_nobuffers,
 404         .writepage = nfs_writepage,
 405         .writepages = nfs_writepages,
 406         .write_begin = nfs_write_begin,
 407         .write_end = nfs_write_end,
 408         .invalidatepage = nfs_invalidate_page,
 409         .releasepage = nfs_release_page,
 410         .direct_IO = nfs_direct_IO,
 411         .launder_page = nfs_launder_page,
 412 };
 413
 414 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
 415 {
 416         struct file *filp = vma->vm_file;
 417         unsigned pagelen;
 418         int ret = -EINVAL;
 419         struct address_space *mapping;
 420
 421         lock_page(page);
 422         mapping = page->mapping;
 423         if (mapping != vma->vm_file->f_path.dentry->d_inode->i_mapping)
 424                 goto out_unlock;
 425
 426         ret = 0;
 427         pagelen = nfs_page_length(page);
 428         if (pagelen == 0)
 429                 goto out_unlock;
 430
 431         ret = nfs_flush_incompatible(filp, page);
 432         if (ret != 0)
 433                 goto out_unlock;
 434
 435         ret = nfs_updatepage(filp, page, 0, pagelen);
 436         if (ret == 0)
 437                 ret = pagelen;
 438 out_unlock:
 439         unlock_page(page);
 440         return ret;
 441 }
 442
 443 static struct vm_operations_struct nfs_file_vm_ops = {
 444         .fault = filemap_fault,
 445         .page_mkwrite = nfs_vm_page_mkwrite,
 446 };
 447
 448 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
 449 {
 450         struct nfs_open_context *ctx;
 451
 452         if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
 453                 return 1;
 454         ctx = nfs_file_open_context(filp);
 455         if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
 456                 return 1;
 457         return 0;
 458 }
 459
 460 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
 461                                 unsigned long nr_segs, loff_t pos)
 462 {
 463         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 464         struct inode * inode = dentry->d_inode;
 465         ssize_t result;
 466         size_t count = iov_length(iov, nr_segs);
 467
 468         if (iocb->ki_filp->f_flags & O_DIRECT)
 469                 return nfs_file_direct_write(iocb, iov, nr_segs, pos);
 470
 471         dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%Ld)\n",
 472                 dentry->d_parent->d_name.name, dentry->d_name.name,
 473                 inode->i_ino, (unsigned long) count, (long long) pos);
 474
 475         result = -EBUSY;
 476         if (IS_SWAPFILE(inode))
 477                 goto out_swapfile;
 478         /*
 479          * O_APPEND implies that we must revalidate the file length.
 480          */
 481         if (iocb->ki_filp->f_flags & O_APPEND) {
 482                 result = nfs_revalidate_file_size(inode, iocb->ki_filp);
 483                 if (result)
 484                         goto out;
 485         }
 486
 487         result = count;
 488         if (!count)
 489                 goto out;
 490
 491         nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 492         result = generic_file_aio_write(iocb, iov, nr_segs, pos);
 493         /* Return error values for O_SYNC and IS_SYNC() */
 494         if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
 495                 int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
 496                 if (err < 0)
 497                         result = err;
 498         }
 499 out:
 500         return result;
 501
 502 out_swapfile:
 503         printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
 504         goto out;
 505 }
 506
 507 static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
 508 {
 509         struct inode *inode = filp->f_mapping->host;
 510         int status = 0;
 511
 512         lock_kernel();
 513         /* Try local locking first */
 514         posix_test_lock(filp, fl);
 515         if (fl->fl_type != F_UNLCK) {
 516                 /* found a conflict */
 517                 goto out;
 518         }
 519
 520         if (nfs_have_delegation(inode, FMODE_READ))
 521                 goto out_noconflict;
 522
 523         if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
 524                 goto out_noconflict;
 525
 526         status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 527 out:
 528         unlock_kernel();
 529         return status;
 530 out_noconflict:
 531         fl->fl_type = F_UNLCK;
 532         goto out;
 533 }
 534
 535 static int do_vfs_lock(struct file *file, struct file_lock *fl)
 536 {
 537         int res = 0;
 538         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 539                 case FL_POSIX:
 540                         res = posix_lock_file_wait(file, fl);
 541                         break;
 542                 case FL_FLOCK:
 543                         res = flock_lock_file_wait(file, fl);
 544                         break;
 545                 default:
 546                         BUG();
 547         }
 548         if (res < 0)
 549                 dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
 550                         " - error %d!\n",
 551                                 __func__, res);
 552         return res;
 553 }
 554
 555 static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
 556 {
 557         struct inode *inode = filp->f_mapping->host;
 558         int status;
 559
 560         /*
 561          * Flush all pending writes before doing anything
 562          * with locks..
 563          */
 564         nfs_sync_mapping(filp->f_mapping);
 565
 566         /* NOTE: special case
 567          *      If we're signalled while cleaning up locks on process exit, we
 568          *      still need to complete the unlock.
 569          */
 570         lock_kernel();
 571         /* Use local locking if mounted with "-onolock" */
 572         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 573                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 574         else
 575                 status = do_vfs_lock(filp, fl);
 576         unlock_kernel();
 577         return status;
 578 }
 579
 580 static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
 581 {
 582         struct inode *inode = filp->f_mapping->host;
 583         int status;
 584
 585         /*
 586          * Flush all pending writes before doing anything
 587          * with locks..
 588          */
 589         status = nfs_sync_mapping(filp->f_mapping);
 590         if (status != 0)
 591                 goto out;
 592
 593         lock_kernel();
 594         /* Use local locking if mounted with "-onolock" */
 595         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 596                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 597         else
 598                 status = do_vfs_lock(filp, fl);
 599         unlock_kernel();
 600         if (status < 0)
 601                 goto out;
 602         /*
 603          * Make sure we clear the cache whenever we try to get the lock.
 604          * This makes locking act as a cache coherency point.
 605          */
 606         nfs_sync_mapping(filp->f_mapping);
 607         if (!nfs_have_delegation(inode, FMODE_READ))
 608                 nfs_zap_caches(inode);
 609 out:
 610         return status;
 611 }
 612
 613 /*
 614  * Lock a (portion of) a file
 615  */
 616 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
 617 {
 618         struct inode * inode = filp->f_mapping->host;
 619         int ret = -ENOLCK;
 620
 621         dprintk("NFS: nfs_lock(f=%s/%ld, t=%x, fl=%x, r=%Ld:%Ld)\n",
 622                         inode->i_sb->s_id, inode->i_ino,
 623                         fl->fl_type, fl->fl_flags,
 624                         (long long)fl->fl_start, (long long)fl->fl_end);
 625         nfs_inc_stats(inode, NFSIOS_VFSLOCK);
 626
 627         /* No mandatory locks over NFS */
 628         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 629                 goto out_err;
 630
 631         if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
 632                 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
 633                 if (ret < 0)
 634                         goto out_err;
 635         }
 636
 637         if (IS_GETLK(cmd))
 638                 ret = do_getlk(filp, cmd, fl);
 639         else if (fl->fl_type == F_UNLCK)
 640                 ret = do_unlk(filp, cmd, fl);
 641         else
 642                 ret = do_setlk(filp, cmd, fl);
 643 out_err:
 644         return ret;
 645 }
 646
 647 /*
 648  * Lock a (portion of) a file
 649  */
 650 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
 651 {
 652         dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
 653                         filp->f_path.dentry->d_inode->i_sb->s_id,
 654                         filp->f_path.dentry->d_inode->i_ino,
 655                         fl->fl_type, fl->fl_flags);
 656
 657         /*
 658          * No BSD flocks over NFS allowed.
 659          * Note: we could try to fake a POSIX lock request here by
 660          * using ((u32) filp | 0x80000000) or some such as the pid.
 661          * Not sure whether that would be unique, though, or whether
 662          * that would break in other places.
 663          */
 664         if (!(fl->fl_flags & FL_FLOCK))
 665                 return -ENOLCK;
 666
 667         /* We're simulating flock() locks using posix locks on the server */
 668         fl->fl_owner = (fl_owner_t)filp;
 669         fl->fl_start = 0;
 670         fl->fl_end = OFFSET_MAX;
 671
 672         if (fl->fl_type == F_UNLCK)
 673                 return do_unlk(filp, cmd, fl);
 674         return do_setlk(filp, cmd, fl);
 675 }
 676
 677 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
 678 {
 679         /*
 680          * There is no protocol support for leases, so we have no way
 681          * to implement them correctly in the face of opens by other
 682          * clients.
 683          */
 684         return -EINVAL;
 685 }