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         dfprintk(VFS, "NFS: open file(%s/%s)\n",
 123                         filp->f_path.dentry->d_parent->d_name.name,
 124                         filp->f_path.dentry->d_name.name);
 125
 126         res = nfs_check_flags(filp->f_flags);
 127         if (res)
 128                 return res;
 129
 130         nfs_inc_stats(inode, NFSIOS_VFSOPEN);
 131         lock_kernel();
 132         res = NFS_PROTO(inode)->file_open(inode, filp);
 133         unlock_kernel();
 134         return res;
 135 }
 136
 137 static int
 138 nfs_file_release(struct inode *inode, struct file *filp)
 139 {
 140         /* Ensure that dirty pages are flushed out with the right creds */
 141         if (filp->f_mode & FMODE_WRITE)
 142                 nfs_wb_all(filp->f_path.dentry->d_inode);
 143         nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
 144         return NFS_PROTO(inode)->file_release(inode, filp);
 145 }
 146
 147 /**
 148  * nfs_revalidate_size - Revalidate the file size
 149  * @inode - pointer to inode struct
 150  * @file - pointer to struct file
 151  *
 152  * Revalidates the file length. This is basically a wrapper around
 153  * nfs_revalidate_inode() that takes into account the fact that we may
 154  * have cached writes (in which case we don't care about the server's
 155  * idea of what the file length is), or O_DIRECT (in which case we
 156  * shouldn't trust the cache).
 157  */
 158 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
 159 {
 160         struct nfs_server *server = NFS_SERVER(inode);
 161         struct nfs_inode *nfsi = NFS_I(inode);
 162
 163         if (server->flags & NFS_MOUNT_NOAC)
 164                 goto force_reval;
 165         if (filp->f_flags & O_DIRECT)
 166                 goto force_reval;
 167         if (nfsi->npages != 0)
 168                 return 0;
 169         if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
 170                 return 0;
 171 force_reval:
 172         return __nfs_revalidate_inode(server, inode);
 173 }
 174
 175 static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
 176 {
 177         dfprintk(VFS, "NFS: llseek file(%s/%s, %lld, %d)\n",
 178                         filp->f_path.dentry->d_parent->d_name.name,
 179                         filp->f_path.dentry->d_name.name,
 180                         offset, origin);
 181
 182         /* origin == SEEK_END => we must revalidate the cached file length */
 183         if (origin == SEEK_END) {
 184                 struct inode *inode = filp->f_mapping->host;
 185                 int retval = nfs_revalidate_file_size(inode, filp);
 186                 if (retval < 0)
 187                         return (loff_t)retval;
 188         }
 189         return remote_llseek(filp, offset, origin);
 190 }
 191
 192 /*
 193  * Helper for nfs_file_flush() and nfs_file_fsync()
 194  *
 195  * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
 196  * disk, but it retrieves and clears ctx->error after synching, despite
 197  * the two being set at the same time in nfs_context_set_write_error().
 198  * This is because the former is used to notify the _next_ call to
 199  * nfs_file_write() that a write error occured, and hence cause it to
 200  * fall back to doing a synchronous write.
 201  */
 202 static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
 203 {
 204         int have_error, status;
 205         int ret = 0;
 206
 207         have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 208         status = nfs_wb_all(inode);
 209         have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 210         if (have_error)
 211                 ret = xchg(&ctx->error, 0);
 212         if (!ret)
 213                 ret = status;
 214         return ret;
 215 }
 216
 217 /*
 218  * Flush all dirty pages, and check for write errors.
 219  *
 220  */
 221 static int
 222 nfs_file_flush(struct file *file, fl_owner_t id)
 223 {
 224         struct nfs_open_context *ctx = nfs_file_open_context(file);
 225         struct inode    *inode = file->f_path.dentry->d_inode;
 226         int             status;
 227
 228         dfprintk(VFS, "nfs: flush(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
 229
 230         if ((file->f_mode & FMODE_WRITE) == 0)
 231                 return 0;
 232         nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
 233
 234         /* Ensure that data+attribute caches are up to date after close() */
 235         status = nfs_do_fsync(ctx, inode);
 236         if (!status)
 237                 nfs_revalidate_inode(NFS_SERVER(inode), inode);
 238         return status;
 239 }
 240
 241 static ssize_t
 242 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
 243                 unsigned long nr_segs, loff_t pos)
 244 {
 245         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 246         struct inode * inode = dentry->d_inode;
 247         ssize_t result;
 248         size_t count = iov_length(iov, nr_segs);
 249
 250         if (iocb->ki_filp->f_flags & O_DIRECT)
 251                 return nfs_file_direct_read(iocb, iov, nr_segs, pos);
 252
 253         dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
 254                 dentry->d_parent->d_name.name, dentry->d_name.name,
 255                 (unsigned long) count, (unsigned long) pos);
 256
 257         result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
 258         nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
 259         if (!result)
 260                 result = generic_file_aio_read(iocb, iov, nr_segs, pos);
 261         return result;
 262 }
 263
 264 static ssize_t
 265 nfs_file_splice_read(struct file *filp, loff_t *ppos,
 266                      struct pipe_inode_info *pipe, size_t count,
 267                      unsigned int flags)
 268 {
 269         struct dentry *dentry = filp->f_path.dentry;
 270         struct inode *inode = dentry->d_inode;
 271         ssize_t res;
 272
 273         dfprintk(VFS, "nfs: splice_read(%s/%s, %lu@%Lu)\n",
 274                 dentry->d_parent->d_name.name, dentry->d_name.name,
 275                 (unsigned long) count, (unsigned long long) *ppos);
 276
 277         res = nfs_revalidate_mapping(inode, filp->f_mapping);
 278         if (!res)
 279                 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
 280         return res;
 281 }
 282
 283 static int
 284 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
 285 {
 286         struct dentry *dentry = file->f_path.dentry;
 287         struct inode *inode = dentry->d_inode;
 288         int     status;
 289
 290         dfprintk(VFS, "nfs: mmap(%s/%s)\n",
 291                 dentry->d_parent->d_name.name, dentry->d_name.name);
 292
 293         status = nfs_revalidate_mapping(inode, file->f_mapping);
 294         if (!status) {
 295                 vma->vm_ops = &nfs_file_vm_ops;
 296                 vma->vm_flags |= VM_CAN_NONLINEAR;
 297                 file_accessed(file);
 298         }
 299         return status;
 300 }
 301
 302 /*
 303  * Flush any dirty pages for this process, and check for write errors.
 304  * The return status from this call provides a reliable indication of
 305  * whether any write errors occurred for this process.
 306  */
 307 static int
 308 nfs_file_fsync(struct file *file, struct dentry *dentry, int datasync)
 309 {
 310         struct nfs_open_context *ctx = nfs_file_open_context(file);
 311         struct inode *inode = dentry->d_inode;
 312
 313         dfprintk(VFS, "NFS: fsync file(%s/%s) datasync %d\n",
 314                         dentry->d_parent->d_name.name, dentry->d_name.name,
 315                         datasync);
 316
 317         nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
 318         return nfs_do_fsync(ctx, inode);
 319 }
 320
 321 /*
 322  * This does the "real" work of the write. We must allocate and lock the
 323  * page to be sent back to the generic routine, which then copies the
 324  * data from user space.
 325  *
 326  * If the writer ends up delaying the write, the writer needs to
 327  * increment the page use counts until he is done with the page.
 328  */
 329 static int nfs_write_begin(struct file *file, struct address_space *mapping,
 330                         loff_t pos, unsigned len, unsigned flags,
 331                         struct page **pagep, void **fsdata)
 332 {
 333         int ret;
 334         pgoff_t index;
 335         struct page *page;
 336         index = pos >> PAGE_CACHE_SHIFT;
 337
 338         dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n",
 339                 file->f_path.dentry->d_parent->d_name.name,
 340                 file->f_path.dentry->d_name.name,
 341                 mapping->host->i_ino, len, (long long) pos);
 342
 343         page = __grab_cache_page(mapping, index);
 344         if (!page)
 345                 return -ENOMEM;
 346         *pagep = page;
 347
 348         ret = nfs_flush_incompatible(file, page);
 349         if (ret) {
 350                 unlock_page(page);
 351                 page_cache_release(page);
 352         }
 353         return ret;
 354 }
 355
 356 static int nfs_write_end(struct file *file, struct address_space *mapping,
 357                         loff_t pos, unsigned len, unsigned copied,
 358                         struct page *page, void *fsdata)
 359 {
 360         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 361         int status;
 362
 363         dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n",
 364                 file->f_path.dentry->d_parent->d_name.name,
 365                 file->f_path.dentry->d_name.name,
 366                 mapping->host->i_ino, len, (long long) pos);
 367
 368         /*
 369          * Zero any uninitialised parts of the page, and then mark the page
 370          * as up to date if it turns out that we're extending the file.
 371          */
 372         if (!PageUptodate(page)) {
 373                 unsigned pglen = nfs_page_length(page);
 374                 unsigned end = offset + len;
 375
 376                 if (pglen == 0) {
 377                         zero_user_segments(page, 0, offset,
 378                                         end, PAGE_CACHE_SIZE);
 379                         SetPageUptodate(page);
 380                 } else if (end >= pglen) {
 381                         zero_user_segment(page, end, PAGE_CACHE_SIZE);
 382                         if (offset == 0)
 383                                 SetPageUptodate(page);
 384                 } else
 385                         zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
 386         }
 387
 388         lock_kernel();
 389         status = nfs_updatepage(file, page, offset, copied);
 390         unlock_kernel();
 391
 392         unlock_page(page);
 393         page_cache_release(page);
 394
 395         if (status < 0)
 396                 return status;
 397         return copied;
 398 }
 399
 400 static void nfs_invalidate_page(struct page *page, unsigned long offset)
 401 {
 402         dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
 403
 404         if (offset != 0)
 405                 return;
 406         /* Cancel any unstarted writes on this page */
 407         nfs_wb_page_cancel(page->mapping->host, page);
 408 }
 409
 410 static int nfs_release_page(struct page *page, gfp_t gfp)
 411 {
 412         dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
 413
 414         /* If PagePrivate() is set, then the page is not freeable */
 415         return 0;
 416 }
 417
 418 static int nfs_launder_page(struct page *page)
 419 {
 420         struct inode *inode = page->mapping->host;
 421
 422         dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
 423                 inode->i_ino, (long long)page_offset(page));
 424
 425         return nfs_wb_page(inode, page);
 426 }
 427
 428 const struct address_space_operations nfs_file_aops = {
 429         .readpage = nfs_readpage,
 430         .readpages = nfs_readpages,
 431         .set_page_dirty = __set_page_dirty_nobuffers,
 432         .writepage = nfs_writepage,
 433         .writepages = nfs_writepages,
 434         .write_begin = nfs_write_begin,
 435         .write_end = nfs_write_end,
 436         .invalidatepage = nfs_invalidate_page,
 437         .releasepage = nfs_release_page,
 438         .direct_IO = nfs_direct_IO,
 439         .launder_page = nfs_launder_page,
 440 };
 441
 442 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
 443 {
 444         struct file *filp = vma->vm_file;
 445         struct dentry *dentry = filp->f_path.dentry;
 446         unsigned pagelen;
 447         int ret = -EINVAL;
 448         struct address_space *mapping;
 449
 450         dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n",
 451                 dentry->d_parent->d_name.name, dentry->d_name.name,
 452                 filp->f_mapping->host->i_ino,
 453                 (long long)page_offset(page));
 454
 455         lock_page(page);
 456         mapping = page->mapping;
 457         if (mapping != dentry->d_inode->i_mapping)
 458                 goto out_unlock;
 459
 460         ret = 0;
 461         pagelen = nfs_page_length(page);
 462         if (pagelen == 0)
 463                 goto out_unlock;
 464
 465         ret = nfs_flush_incompatible(filp, page);
 466         if (ret != 0)
 467                 goto out_unlock;
 468
 469         ret = nfs_updatepage(filp, page, 0, pagelen);
 470         if (ret == 0)
 471                 ret = pagelen;
 472 out_unlock:
 473         unlock_page(page);
 474         return ret;
 475 }
 476
 477 static struct vm_operations_struct nfs_file_vm_ops = {
 478         .fault = filemap_fault,
 479         .page_mkwrite = nfs_vm_page_mkwrite,
 480 };
 481
 482 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
 483 {
 484         struct nfs_open_context *ctx;
 485
 486         if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
 487                 return 1;
 488         ctx = nfs_file_open_context(filp);
 489         if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
 490                 return 1;
 491         return 0;
 492 }
 493
 494 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
 495                                 unsigned long nr_segs, loff_t pos)
 496 {
 497         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 498         struct inode * inode = dentry->d_inode;
 499         ssize_t result;
 500         size_t count = iov_length(iov, nr_segs);
 501
 502         if (iocb->ki_filp->f_flags & O_DIRECT)
 503                 return nfs_file_direct_write(iocb, iov, nr_segs, pos);
 504
 505         dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%Ld)\n",
 506                 dentry->d_parent->d_name.name, dentry->d_name.name,
 507                 inode->i_ino, (unsigned long) count, (long long) pos);
 508
 509         result = -EBUSY;
 510         if (IS_SWAPFILE(inode))
 511                 goto out_swapfile;
 512         /*
 513          * O_APPEND implies that we must revalidate the file length.
 514          */
 515         if (iocb->ki_filp->f_flags & O_APPEND) {
 516                 result = nfs_revalidate_file_size(inode, iocb->ki_filp);
 517                 if (result)
 518                         goto out;
 519         }
 520
 521         result = count;
 522         if (!count)
 523                 goto out;
 524
 525         nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 526         result = generic_file_aio_write(iocb, iov, nr_segs, pos);
 527         /* Return error values for O_SYNC and IS_SYNC() */
 528         if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
 529                 int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
 530                 if (err < 0)
 531                         result = err;
 532         }
 533 out:
 534         return result;
 535
 536 out_swapfile:
 537         printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
 538         goto out;
 539 }
 540
 541 static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
 542 {
 543         struct inode *inode = filp->f_mapping->host;
 544         int status = 0;
 545
 546         lock_kernel();
 547         /* Try local locking first */
 548         posix_test_lock(filp, fl);
 549         if (fl->fl_type != F_UNLCK) {
 550                 /* found a conflict */
 551                 goto out;
 552         }
 553
 554         if (nfs_have_delegation(inode, FMODE_READ))
 555                 goto out_noconflict;
 556
 557         if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
 558                 goto out_noconflict;
 559
 560         status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 561 out:
 562         unlock_kernel();
 563         return status;
 564 out_noconflict:
 565         fl->fl_type = F_UNLCK;
 566         goto out;
 567 }
 568
 569 static int do_vfs_lock(struct file *file, struct file_lock *fl)
 570 {
 571         int res = 0;
 572         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 573                 case FL_POSIX:
 574                         res = posix_lock_file_wait(file, fl);
 575                         break;
 576                 case FL_FLOCK:
 577                         res = flock_lock_file_wait(file, fl);
 578                         break;
 579                 default:
 580                         BUG();
 581         }
 582         if (res < 0)
 583                 dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
 584                         " - error %d!\n",
 585                                 __func__, res);
 586         return res;
 587 }
 588
 589 static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
 590 {
 591         struct inode *inode = filp->f_mapping->host;
 592         int status;
 593
 594         /*
 595          * Flush all pending writes before doing anything
 596          * with locks..
 597          */
 598         nfs_sync_mapping(filp->f_mapping);
 599
 600         /* NOTE: special case
 601          *      If we're signalled while cleaning up locks on process exit, we
 602          *      still need to complete the unlock.
 603          */
 604         lock_kernel();
 605         /* Use local locking if mounted with "-onolock" */
 606         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 607                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 608         else
 609                 status = do_vfs_lock(filp, fl);
 610         unlock_kernel();
 611         return status;
 612 }
 613
 614 static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
 615 {
 616         struct inode *inode = filp->f_mapping->host;
 617         int status;
 618
 619         /*
 620          * Flush all pending writes before doing anything
 621          * with locks..
 622          */
 623         status = nfs_sync_mapping(filp->f_mapping);
 624         if (status != 0)
 625                 goto out;
 626
 627         lock_kernel();
 628         /* Use local locking if mounted with "-onolock" */
 629         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 630                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 631         else
 632                 status = do_vfs_lock(filp, fl);
 633         unlock_kernel();
 634         if (status < 0)
 635                 goto out;
 636         /*
 637          * Make sure we clear the cache whenever we try to get the lock.
 638          * This makes locking act as a cache coherency point.
 639          */
 640         nfs_sync_mapping(filp->f_mapping);
 641         if (!nfs_have_delegation(inode, FMODE_READ))
 642                 nfs_zap_caches(inode);
 643 out:
 644         return status;
 645 }
 646
 647 /*
 648  * Lock a (portion of) a file
 649  */
 650 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
 651 {
 652         struct inode * inode = filp->f_mapping->host;
 653         int ret = -ENOLCK;
 654
 655         dprintk("NFS: nfs_lock(f=%s/%ld, t=%x, fl=%x, r=%Ld:%Ld)\n",
 656                         inode->i_sb->s_id, inode->i_ino,
 657                         fl->fl_type, fl->fl_flags,
 658                         (long long)fl->fl_start, (long long)fl->fl_end);
 659         nfs_inc_stats(inode, NFSIOS_VFSLOCK);
 660
 661         /* No mandatory locks over NFS */
 662         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 663                 goto out_err;
 664
 665         if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
 666                 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
 667                 if (ret < 0)
 668                         goto out_err;
 669         }
 670
 671         if (IS_GETLK(cmd))
 672                 ret = do_getlk(filp, cmd, fl);
 673         else if (fl->fl_type == F_UNLCK)
 674                 ret = do_unlk(filp, cmd, fl);
 675         else
 676                 ret = do_setlk(filp, cmd, fl);
 677 out_err:
 678         return ret;
 679 }
 680
 681 /*
 682  * Lock a (portion of) a file
 683  */
 684 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
 685 {
 686         dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
 687                         filp->f_path.dentry->d_inode->i_sb->s_id,
 688                         filp->f_path.dentry->d_inode->i_ino,
 689                         fl->fl_type, fl->fl_flags);
 690
 691         /*
 692          * No BSD flocks over NFS allowed.
 693          * Note: we could try to fake a POSIX lock request here by
 694          * using ((u32) filp | 0x80000000) or some such as the pid.
 695          * Not sure whether that would be unique, though, or whether
 696          * that would break in other places.
 697          */
 698         if (!(fl->fl_flags & FL_FLOCK))
 699                 return -ENOLCK;
 700
 701         /* We're simulating flock() locks using posix locks on the server */
 702         fl->fl_owner = (fl_owner_t)filp;
 703         fl->fl_start = 0;
 704         fl->fl_end = OFFSET_MAX;
 705
 706         if (fl->fl_type == F_UNLCK)
 707                 return do_unlk(filp, cmd, fl);
 708         return do_setlk(filp, cmd, fl);
 709 }
 710
 711 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
 712 {
 713         /*
 714          * There is no protocol support for leases, so we have no way
 715          * to implement them correctly in the face of opens by other
 716          * clients.
 717          */
 718         return -EINVAL;
 719 }