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/aio.h>
  30
  31 #include <asm/uaccess.h>
  32 #include <asm/system.h>
  33
  34 #include "delegation.h"
  35 #include "internal.h"
  36 #include "iostat.h"
  37 #include "fscache.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_splice_write(struct pipe_inode_info *pipe,
  51                                         struct file *filp, loff_t *ppos,
  52                                         size_t count, unsigned int flags);
  53 static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
  54                                 unsigned long nr_segs, loff_t pos);
  55 static int  nfs_file_flush(struct file *, fl_owner_t id);
  56 static int  nfs_file_fsync(struct file *, struct dentry *dentry, int datasync);
  57 static int nfs_check_flags(int flags);
  58 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
  59 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
  60 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);
  61
  62 static struct vm_operations_struct nfs_file_vm_ops;
  63
  64 const struct file_operations nfs_file_operations = {
  65         .llseek         = nfs_file_llseek,
  66         .read           = do_sync_read,
  67         .write          = do_sync_write,
  68         .aio_read       = nfs_file_read,
  69         .aio_write      = nfs_file_write,
  70         .mmap           = nfs_file_mmap,
  71         .open           = nfs_file_open,
  72         .flush          = nfs_file_flush,
  73         .release        = nfs_file_release,
  74         .fsync          = nfs_file_fsync,
  75         .lock           = nfs_lock,
  76         .flock          = nfs_flock,
  77         .splice_read    = nfs_file_splice_read,
  78         .splice_write   = nfs_file_splice_write,
  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         dprintk("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         res = nfs_open(inode, filp);
 132         return res;
 133 }
 134
 135 static int
 136 nfs_file_release(struct inode *inode, struct file *filp)
 137 {
 138         struct dentry *dentry = filp->f_path.dentry;
 139
 140         dprintk("NFS: release(%s/%s)\n",
 141                         dentry->d_parent->d_name.name,
 142                         dentry->d_name.name);
 143
 144         nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
 145         return nfs_release(inode, filp);
 146 }
 147
 148 /**
 149  * nfs_revalidate_size - Revalidate the file size
 150  * @inode - pointer to inode struct
 151  * @file - pointer to struct file
 152  *
 153  * Revalidates the file length. This is basically a wrapper around
 154  * nfs_revalidate_inode() that takes into account the fact that we may
 155  * have cached writes (in which case we don't care about the server's
 156  * idea of what the file length is), or O_DIRECT (in which case we
 157  * shouldn't trust the cache).
 158  */
 159 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
 160 {
 161         struct nfs_server *server = NFS_SERVER(inode);
 162         struct nfs_inode *nfsi = NFS_I(inode);
 163
 164         if (server->flags & NFS_MOUNT_NOAC)
 165                 goto force_reval;
 166         if (filp->f_flags & O_DIRECT)
 167                 goto force_reval;
 168         if (nfsi->npages != 0)
 169                 return 0;
 170         if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
 171                 return 0;
 172 force_reval:
 173         return __nfs_revalidate_inode(server, inode);
 174 }
 175
 176 static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
 177 {
 178         loff_t loff;
 179
 180         dprintk("NFS: llseek file(%s/%s, %lld, %d)\n",
 181                         filp->f_path.dentry->d_parent->d_name.name,
 182                         filp->f_path.dentry->d_name.name,
 183                         offset, origin);
 184
 185         /* origin == SEEK_END => we must revalidate the cached file length */
 186         if (origin == SEEK_END) {
 187                 struct inode *inode = filp->f_mapping->host;
 188
 189                 int retval = nfs_revalidate_file_size(inode, filp);
 190                 if (retval < 0)
 191                         return (loff_t)retval;
 192
 193                 spin_lock(&inode->i_lock);
 194                 loff = generic_file_llseek_unlocked(filp, offset, origin);
 195                 spin_unlock(&inode->i_lock);
 196         } else
 197                 loff = generic_file_llseek_unlocked(filp, offset, origin);
 198         return loff;
 199 }
 200
 201 /*
 202  * Helper for nfs_file_flush() and nfs_file_fsync()
 203  *
 204  * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
 205  * disk, but it retrieves and clears ctx->error after synching, despite
 206  * the two being set at the same time in nfs_context_set_write_error().
 207  * This is because the former is used to notify the _next_ call to
 208  * nfs_file_write() that a write error occured, and hence cause it to
 209  * fall back to doing a synchronous write.
 210  */
 211 static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
 212 {
 213         int have_error, status;
 214         int ret = 0;
 215
 216         have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 217         status = nfs_wb_all(inode);
 218         have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 219         if (have_error)
 220                 ret = xchg(&ctx->error, 0);
 221         if (!ret)
 222                 ret = status;
 223         return ret;
 224 }
 225
 226 /*
 227  * Flush all dirty pages, and check for write errors.
 228  */
 229 static int
 230 nfs_file_flush(struct file *file, fl_owner_t id)
 231 {
 232         struct nfs_open_context *ctx = nfs_file_open_context(file);
 233         struct dentry   *dentry = file->f_path.dentry;
 234         struct inode    *inode = dentry->d_inode;
 235
 236         dprintk("NFS: flush(%s/%s)\n",
 237                         dentry->d_parent->d_name.name,
 238                         dentry->d_name.name);
 239
 240         if ((file->f_mode & FMODE_WRITE) == 0)
 241                 return 0;
 242         nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
 243
 244         /* Flush writes to the server and return any errors */
 245         return nfs_do_fsync(ctx, inode);
 246 }
 247
 248 static ssize_t
 249 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
 250                 unsigned long nr_segs, loff_t pos)
 251 {
 252         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 253         struct inode * inode = dentry->d_inode;
 254         ssize_t result;
 255         size_t count = iov_length(iov, nr_segs);
 256
 257         if (iocb->ki_filp->f_flags & O_DIRECT)
 258                 return nfs_file_direct_read(iocb, iov, nr_segs, pos);
 259
 260         dprintk("NFS: read(%s/%s, %lu@%lu)\n",
 261                 dentry->d_parent->d_name.name, dentry->d_name.name,
 262                 (unsigned long) count, (unsigned long) pos);
 263
 264         result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
 265         nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
 266         if (!result)
 267                 result = generic_file_aio_read(iocb, iov, nr_segs, pos);
 268         return result;
 269 }
 270
 271 static ssize_t
 272 nfs_file_splice_read(struct file *filp, loff_t *ppos,
 273                      struct pipe_inode_info *pipe, size_t count,
 274                      unsigned int flags)
 275 {
 276         struct dentry *dentry = filp->f_path.dentry;
 277         struct inode *inode = dentry->d_inode;
 278         ssize_t res;
 279
 280         dprintk("NFS: splice_read(%s/%s, %lu@%Lu)\n",
 281                 dentry->d_parent->d_name.name, dentry->d_name.name,
 282                 (unsigned long) count, (unsigned long long) *ppos);
 283
 284         res = nfs_revalidate_mapping(inode, filp->f_mapping);
 285         if (!res)
 286                 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
 287         return res;
 288 }
 289
 290 static int
 291 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
 292 {
 293         struct dentry *dentry = file->f_path.dentry;
 294         struct inode *inode = dentry->d_inode;
 295         int     status;
 296
 297         dprintk("NFS: mmap(%s/%s)\n",
 298                 dentry->d_parent->d_name.name, dentry->d_name.name);
 299
 300         /* Note: generic_file_mmap() returns ENOSYS on nommu systems
 301          *       so we call that before revalidating the mapping
 302          */
 303         status = generic_file_mmap(file, vma);
 304         if (!status) {
 305                 vma->vm_ops = &nfs_file_vm_ops;
 306                 status = nfs_revalidate_mapping(inode, file->f_mapping);
 307         }
 308         return status;
 309 }
 310
 311 /*
 312  * Flush any dirty pages for this process, and check for write errors.
 313  * The return status from this call provides a reliable indication of
 314  * whether any write errors occurred for this process.
 315  */
 316 static int
 317 nfs_file_fsync(struct file *file, struct dentry *dentry, int datasync)
 318 {
 319         struct nfs_open_context *ctx = nfs_file_open_context(file);
 320         struct inode *inode = dentry->d_inode;
 321
 322         dprintk("NFS: fsync file(%s/%s) datasync %d\n",
 323                         dentry->d_parent->d_name.name, dentry->d_name.name,
 324                         datasync);
 325
 326         nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
 327         return nfs_do_fsync(ctx, inode);
 328 }
 329
 330 /*
 331  * This does the "real" work of the write. We must allocate and lock the
 332  * page to be sent back to the generic routine, which then copies the
 333  * data from user space.
 334  *
 335  * If the writer ends up delaying the write, the writer needs to
 336  * increment the page use counts until he is done with the page.
 337  */
 338 static int nfs_write_begin(struct file *file, struct address_space *mapping,
 339                         loff_t pos, unsigned len, unsigned flags,
 340                         struct page **pagep, void **fsdata)
 341 {
 342         int ret;
 343         pgoff_t index;
 344         struct page *page;
 345         index = pos >> PAGE_CACHE_SHIFT;
 346
 347         dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n",
 348                 file->f_path.dentry->d_parent->d_name.name,
 349                 file->f_path.dentry->d_name.name,
 350                 mapping->host->i_ino, len, (long long) pos);
 351
 352         /*
 353          * Prevent starvation issues if someone is doing a consistency
 354          * sync-to-disk
 355          */
 356         ret = wait_on_bit(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
 357                         nfs_wait_bit_killable, TASK_KILLABLE);
 358         if (ret)
 359                 return ret;
 360
 361         page = grab_cache_page_write_begin(mapping, index, flags);
 362         if (!page)
 363                 return -ENOMEM;
 364         *pagep = page;
 365
 366         ret = nfs_flush_incompatible(file, page);
 367         if (ret) {
 368                 unlock_page(page);
 369                 page_cache_release(page);
 370         }
 371         return ret;
 372 }
 373
 374 static int nfs_write_end(struct file *file, struct address_space *mapping,
 375                         loff_t pos, unsigned len, unsigned copied,
 376                         struct page *page, void *fsdata)
 377 {
 378         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 379         int status;
 380
 381         dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n",
 382                 file->f_path.dentry->d_parent->d_name.name,
 383                 file->f_path.dentry->d_name.name,
 384                 mapping->host->i_ino, len, (long long) pos);
 385
 386         /*
 387          * Zero any uninitialised parts of the page, and then mark the page
 388          * as up to date if it turns out that we're extending the file.
 389          */
 390         if (!PageUptodate(page)) {
 391                 unsigned pglen = nfs_page_length(page);
 392                 unsigned end = offset + len;
 393
 394                 if (pglen == 0) {
 395                         zero_user_segments(page, 0, offset,
 396                                         end, PAGE_CACHE_SIZE);
 397                         SetPageUptodate(page);
 398                 } else if (end >= pglen) {
 399                         zero_user_segment(page, end, PAGE_CACHE_SIZE);
 400                         if (offset == 0)
 401                                 SetPageUptodate(page);
 402                 } else
 403                         zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
 404         }
 405
 406         status = nfs_updatepage(file, page, offset, copied);
 407
 408         unlock_page(page);
 409         page_cache_release(page);
 410
 411         if (status < 0)
 412                 return status;
 413         return copied;
 414 }
 415
 416 /*
 417  * Partially or wholly invalidate a page
 418  * - Release the private state associated with a page if undergoing complete
 419  *   page invalidation
 420  * - Called if either PG_private or PG_fscache is set on the page
 421  * - Caller holds page lock
 422  */
 423 static void nfs_invalidate_page(struct page *page, unsigned long offset)
 424 {
 425         dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
 426
 427         if (offset != 0)
 428                 return;
 429         /* Cancel any unstarted writes on this page */
 430         nfs_wb_page_cancel(page->mapping->host, page);
 431
 432         nfs_fscache_invalidate_page(page, page->mapping->host);
 433 }
 434
 435 /*
 436  * Attempt to release the private state associated with a page
 437  * - Called if either PG_private or PG_fscache is set on the page
 438  * - Caller holds page lock
 439  * - Return true (may release page) or false (may not)
 440  */
 441 static int nfs_release_page(struct page *page, gfp_t gfp)
 442 {
 443         dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
 444
 445         /* If PagePrivate() is set, then the page is not freeable */
 446         if (PagePrivate(page))
 447                 return 0;
 448         return nfs_fscache_release_page(page, gfp);
 449 }
 450
 451 /*
 452  * Attempt to clear the private state associated with a page when an error
 453  * occurs that requires the cached contents of an inode to be written back or
 454  * destroyed
 455  * - Called if either PG_private or fscache is set on the page
 456  * - Caller holds page lock
 457  * - Return 0 if successful, -error otherwise
 458  */
 459 static int nfs_launder_page(struct page *page)
 460 {
 461         struct inode *inode = page->mapping->host;
 462         struct nfs_inode *nfsi = NFS_I(inode);
 463
 464         dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
 465                 inode->i_ino, (long long)page_offset(page));
 466
 467         nfs_fscache_wait_on_page_write(nfsi, page);
 468         return nfs_wb_page(inode, page);
 469 }
 470
 471 const struct address_space_operations nfs_file_aops = {
 472         .readpage = nfs_readpage,
 473         .readpages = nfs_readpages,
 474         .set_page_dirty = __set_page_dirty_nobuffers,
 475         .writepage = nfs_writepage,
 476         .writepages = nfs_writepages,
 477         .write_begin = nfs_write_begin,
 478         .write_end = nfs_write_end,
 479         .invalidatepage = nfs_invalidate_page,
 480         .releasepage = nfs_release_page,
 481         .direct_IO = nfs_direct_IO,
 482         .launder_page = nfs_launder_page,
 483 };
 484
 485 /*
 486  * Notification that a PTE pointing to an NFS page is about to be made
 487  * writable, implying that someone is about to modify the page through a
 488  * shared-writable mapping
 489  */
 490 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 491 {
 492         struct page *page = vmf->page;
 493         struct file *filp = vma->vm_file;
 494         struct dentry *dentry = filp->f_path.dentry;
 495         unsigned pagelen;
 496         int ret = -EINVAL;
 497         struct address_space *mapping;
 498
 499         dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n",
 500                 dentry->d_parent->d_name.name, dentry->d_name.name,
 501                 filp->f_mapping->host->i_ino,
 502                 (long long)page_offset(page));
 503
 504         /* make sure the cache has finished storing the page */
 505         nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);
 506
 507         lock_page(page);
 508         mapping = page->mapping;
 509         if (mapping != dentry->d_inode->i_mapping)
 510                 goto out_unlock;
 511
 512         ret = 0;
 513         pagelen = nfs_page_length(page);
 514         if (pagelen == 0)
 515                 goto out_unlock;
 516
 517         ret = nfs_flush_incompatible(filp, page);
 518         if (ret != 0)
 519                 goto out_unlock;
 520
 521         ret = nfs_updatepage(filp, page, 0, pagelen);
 522 out_unlock:
 523         if (!ret)
 524                 return VM_FAULT_LOCKED;
 525         unlock_page(page);
 526         return VM_FAULT_SIGBUS;
 527 }
 528
 529 static struct vm_operations_struct nfs_file_vm_ops = {
 530         .fault = filemap_fault,
 531         .page_mkwrite = nfs_vm_page_mkwrite,
 532 };
 533
 534 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
 535 {
 536         struct nfs_open_context *ctx;
 537
 538         if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
 539                 return 1;
 540         ctx = nfs_file_open_context(filp);
 541         if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
 542                 return 1;
 543         return 0;
 544 }
 545
 546 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
 547                                 unsigned long nr_segs, loff_t pos)
 548 {
 549         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 550         struct inode * inode = dentry->d_inode;
 551         ssize_t result;
 552         size_t count = iov_length(iov, nr_segs);
 553
 554         if (iocb->ki_filp->f_flags & O_DIRECT)
 555                 return nfs_file_direct_write(iocb, iov, nr_segs, pos);
 556
 557         dprintk("NFS: write(%s/%s, %lu@%Ld)\n",
 558                 dentry->d_parent->d_name.name, dentry->d_name.name,
 559                 (unsigned long) count, (long long) pos);
 560
 561         result = -EBUSY;
 562         if (IS_SWAPFILE(inode))
 563                 goto out_swapfile;
 564         /*
 565          * O_APPEND implies that we must revalidate the file length.
 566          */
 567         if (iocb->ki_filp->f_flags & O_APPEND) {
 568                 result = nfs_revalidate_file_size(inode, iocb->ki_filp);
 569                 if (result)
 570                         goto out;
 571         }
 572
 573         result = count;
 574         if (!count)
 575                 goto out;
 576
 577         nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 578         result = generic_file_aio_write(iocb, iov, nr_segs, pos);
 579         /* Return error values for O_SYNC and IS_SYNC() */
 580         if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
 581                 int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
 582                 if (err < 0)
 583                         result = err;
 584         }
 585 out:
 586         return result;
 587
 588 out_swapfile:
 589         printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
 590         goto out;
 591 }
 592
 593 static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
 594                                      struct file *filp, loff_t *ppos,
 595                                      size_t count, unsigned int flags)
 596 {
 597         struct dentry *dentry = filp->f_path.dentry;
 598         struct inode *inode = dentry->d_inode;
 599         ssize_t ret;
 600
 601         dprintk("NFS splice_write(%s/%s, %lu@%llu)\n",
 602                 dentry->d_parent->d_name.name, dentry->d_name.name,
 603                 (unsigned long) count, (unsigned long long) *ppos);
 604
 605         /*
 606          * The combination of splice and an O_APPEND destination is disallowed.
 607          */
 608
 609         nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 610
 611         ret = generic_file_splice_write(pipe, filp, ppos, count, flags);
 612         if (ret >= 0 && nfs_need_sync_write(filp, inode)) {
 613                 int err = nfs_do_fsync(nfs_file_open_context(filp), inode);
 614                 if (err < 0)
 615                         ret = err;
 616         }
 617         return ret;
 618 }
 619
 620 static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
 621 {
 622         struct inode *inode = filp->f_mapping->host;
 623         int status = 0;
 624
 625         /* Try local locking first */
 626         posix_test_lock(filp, fl);
 627         if (fl->fl_type != F_UNLCK) {
 628                 /* found a conflict */
 629                 goto out;
 630         }
 631
 632         if (nfs_have_delegation(inode, FMODE_READ))
 633                 goto out_noconflict;
 634
 635         if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
 636                 goto out_noconflict;
 637
 638         status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 639 out:
 640         return status;
 641 out_noconflict:
 642         fl->fl_type = F_UNLCK;
 643         goto out;
 644 }
 645
 646 static int do_vfs_lock(struct file *file, struct file_lock *fl)
 647 {
 648         int res = 0;
 649         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 650                 case FL_POSIX:
 651                         res = posix_lock_file_wait(file, fl);
 652                         break;
 653                 case FL_FLOCK:
 654                         res = flock_lock_file_wait(file, fl);
 655                         break;
 656                 default:
 657                         BUG();
 658         }
 659         if (res < 0)
 660                 dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
 661                         " - error %d!\n",
 662                                 __func__, res);
 663         return res;
 664 }
 665
 666 static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
 667 {
 668         struct inode *inode = filp->f_mapping->host;
 669         int status;
 670
 671         /*
 672          * Flush all pending writes before doing anything
 673          * with locks..
 674          */
 675         nfs_sync_mapping(filp->f_mapping);
 676
 677         /* NOTE: special case
 678          *      If we're signalled while cleaning up locks on process exit, we
 679          *      still need to complete the unlock.
 680          */
 681         /* Use local locking if mounted with "-onolock" */
 682         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 683                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 684         else
 685                 status = do_vfs_lock(filp, fl);
 686         return status;
 687 }
 688
 689 static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
 690 {
 691         struct inode *inode = filp->f_mapping->host;
 692         int status;
 693
 694         /*
 695          * Flush all pending writes before doing anything
 696          * with locks..
 697          */
 698         status = nfs_sync_mapping(filp->f_mapping);
 699         if (status != 0)
 700                 goto out;
 701
 702         /* Use local locking if mounted with "-onolock" */
 703         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 704                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 705         else
 706                 status = do_vfs_lock(filp, fl);
 707         if (status < 0)
 708                 goto out;
 709         /*
 710          * Make sure we clear the cache whenever we try to get the lock.
 711          * This makes locking act as a cache coherency point.
 712          */
 713         nfs_sync_mapping(filp->f_mapping);
 714         if (!nfs_have_delegation(inode, FMODE_READ))
 715                 nfs_zap_caches(inode);
 716 out:
 717         return status;
 718 }
 719
 720 /*
 721  * Lock a (portion of) a file
 722  */
 723 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
 724 {
 725         struct inode *inode = filp->f_mapping->host;
 726         int ret = -ENOLCK;
 727
 728         dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n",
 729                         filp->f_path.dentry->d_parent->d_name.name,
 730                         filp->f_path.dentry->d_name.name,
 731                         fl->fl_type, fl->fl_flags,
 732                         (long long)fl->fl_start, (long long)fl->fl_end);
 733
 734         nfs_inc_stats(inode, NFSIOS_VFSLOCK);
 735
 736         /* No mandatory locks over NFS */
 737         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 738                 goto out_err;
 739
 740         if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
 741                 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
 742                 if (ret < 0)
 743                         goto out_err;
 744         }
 745
 746         if (IS_GETLK(cmd))
 747                 ret = do_getlk(filp, cmd, fl);
 748         else if (fl->fl_type == F_UNLCK)
 749                 ret = do_unlk(filp, cmd, fl);
 750         else
 751                 ret = do_setlk(filp, cmd, fl);
 752 out_err:
 753         return ret;
 754 }
 755
 756 /*
 757  * Lock a (portion of) a file
 758  */
 759 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
 760 {
 761         dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n",
 762                         filp->f_path.dentry->d_parent->d_name.name,
 763                         filp->f_path.dentry->d_name.name,
 764                         fl->fl_type, fl->fl_flags);
 765
 766         if (!(fl->fl_flags & FL_FLOCK))
 767                 return -ENOLCK;
 768
 769         /* We're simulating flock() locks using posix locks on the server */
 770         fl->fl_owner = (fl_owner_t)filp;
 771         fl->fl_start = 0;
 772         fl->fl_end = OFFSET_MAX;
 773
 774         if (fl->fl_type == F_UNLCK)
 775                 return do_unlk(filp, cmd, fl);
 776         return do_setlk(filp, cmd, fl);
 777 }
 778
 779 /*
 780  * There is no protocol support for leases, so we have no way to implement
 781  * them correctly in the face of opens by other clients.
 782  */
 783 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
 784 {
 785         dprintk("NFS: setlease(%s/%s, arg=%ld)\n",
 786                         file->f_path.dentry->d_parent->d_name.name,
 787                         file->f_path.dentry->d_name.name, arg);
 788
 789         return -EINVAL;
 790 }