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 #include "fscache.h"
  39
  40 #define NFSDBG_FACILITY         NFSDBG_FILE
  41
  42 static int nfs_file_open(struct inode *, struct file *);
  43 static int nfs_file_release(struct inode *, struct file *);
  44 static loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
  45 static int  nfs_file_mmap(struct file *, struct vm_area_struct *);
  46 static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos,
  47                                         struct pipe_inode_info *pipe,
  48                                         size_t count, unsigned int flags);
  49 static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
  50                                 unsigned long nr_segs, loff_t pos);
  51 static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
  52                                 unsigned long nr_segs, loff_t pos);
  53 static int  nfs_file_flush(struct file *, fl_owner_t id);
  54 static int  nfs_file_fsync(struct file *, struct dentry *dentry, int datasync);
  55 static int nfs_check_flags(int flags);
  56 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
  57 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
  58 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);
  59
  60 static struct vm_operations_struct nfs_file_vm_ops;
  61
  62 const struct file_operations nfs_file_operations = {
  63         .llseek         = nfs_file_llseek,
  64         .read           = do_sync_read,
  65         .write          = do_sync_write,
  66         .aio_read       = nfs_file_read,
  67         .aio_write      = nfs_file_write,
  68         .mmap           = nfs_file_mmap,
  69         .open           = nfs_file_open,
  70         .flush          = nfs_file_flush,
  71         .release        = nfs_file_release,
  72         .fsync          = nfs_file_fsync,
  73         .lock           = nfs_lock,
  74         .flock          = nfs_flock,
  75         .splice_read    = nfs_file_splice_read,
  76         .check_flags    = nfs_check_flags,
  77         .setlease       = nfs_setlease,
  78 };
  79
  80 const struct inode_operations nfs_file_inode_operations = {
  81         .permission     = nfs_permission,
  82         .getattr        = nfs_getattr,
  83         .setattr        = nfs_setattr,
  84 };
  85
  86 #ifdef CONFIG_NFS_V3
  87 const struct inode_operations nfs3_file_inode_operations = {
  88         .permission     = nfs_permission,
  89         .getattr        = nfs_getattr,
  90         .setattr        = nfs_setattr,
  91         .listxattr      = nfs3_listxattr,
  92         .getxattr       = nfs3_getxattr,
  93         .setxattr       = nfs3_setxattr,
  94         .removexattr    = nfs3_removexattr,
  95 };
  96 #endif  /* CONFIG_NFS_v3 */
  97
  98 /* Hack for future NFS swap support */
  99 #ifndef IS_SWAPFILE
 100 # define IS_SWAPFILE(inode)     (0)
 101 #endif
 102
 103 static int nfs_check_flags(int flags)
 104 {
 105         if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
 106                 return -EINVAL;
 107
 108         return 0;
 109 }
 110
 111 /*
 112  * Open file
 113  */
 114 static int
 115 nfs_file_open(struct inode *inode, struct file *filp)
 116 {
 117         int res;
 118
 119         dprintk("NFS: open file(%s/%s)\n",
 120                         filp->f_path.dentry->d_parent->d_name.name,
 121                         filp->f_path.dentry->d_name.name);
 122
 123         res = nfs_check_flags(filp->f_flags);
 124         if (res)
 125                 return res;
 126
 127         nfs_inc_stats(inode, NFSIOS_VFSOPEN);
 128         res = nfs_open(inode, filp);
 129         return res;
 130 }
 131
 132 static int
 133 nfs_file_release(struct inode *inode, struct file *filp)
 134 {
 135         struct dentry *dentry = filp->f_path.dentry;
 136
 137         dprintk("NFS: release(%s/%s)\n",
 138                         dentry->d_parent->d_name.name,
 139                         dentry->d_name.name);
 140
 141         nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
 142         return nfs_release(inode, filp);
 143 }
 144
 145 /**
 146  * nfs_revalidate_size - Revalidate the file size
 147  * @inode - pointer to inode struct
 148  * @file - pointer to struct file
 149  *
 150  * Revalidates the file length. This is basically a wrapper around
 151  * nfs_revalidate_inode() that takes into account the fact that we may
 152  * have cached writes (in which case we don't care about the server's
 153  * idea of what the file length is), or O_DIRECT (in which case we
 154  * shouldn't trust the cache).
 155  */
 156 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
 157 {
 158         struct nfs_server *server = NFS_SERVER(inode);
 159         struct nfs_inode *nfsi = NFS_I(inode);
 160
 161         if (server->flags & NFS_MOUNT_NOAC)
 162                 goto force_reval;
 163         if (filp->f_flags & O_DIRECT)
 164                 goto force_reval;
 165         if (nfsi->npages != 0)
 166                 return 0;
 167         if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
 168                 return 0;
 169 force_reval:
 170         return __nfs_revalidate_inode(server, inode);
 171 }
 172
 173 static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
 174 {
 175         loff_t loff;
 176
 177         dprintk("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
 186                 int retval = nfs_revalidate_file_size(inode, filp);
 187                 if (retval < 0)
 188                         return (loff_t)retval;
 189
 190                 spin_lock(&inode->i_lock);
 191                 loff = generic_file_llseek_unlocked(filp, offset, origin);
 192                 spin_unlock(&inode->i_lock);
 193         } else
 194                 loff = generic_file_llseek_unlocked(filp, offset, origin);
 195         return loff;
 196 }
 197
 198 /*
 199  * Helper for nfs_file_flush() and nfs_file_fsync()
 200  *
 201  * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
 202  * disk, but it retrieves and clears ctx->error after synching, despite
 203  * the two being set at the same time in nfs_context_set_write_error().
 204  * This is because the former is used to notify the _next_ call to
 205  * nfs_file_write() that a write error occured, and hence cause it to
 206  * fall back to doing a synchronous write.
 207  */
 208 static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
 209 {
 210         int have_error, status;
 211         int ret = 0;
 212
 213         have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 214         status = nfs_wb_all(inode);
 215         have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 216         if (have_error)
 217                 ret = xchg(&ctx->error, 0);
 218         if (!ret)
 219                 ret = status;
 220         return ret;
 221 }
 222
 223 /*
 224  * Flush all dirty pages, and check for write errors.
 225  */
 226 static int
 227 nfs_file_flush(struct file *file, fl_owner_t id)
 228 {
 229         struct nfs_open_context *ctx = nfs_file_open_context(file);
 230         struct dentry   *dentry = file->f_path.dentry;
 231         struct inode    *inode = dentry->d_inode;
 232
 233         dprintk("NFS: flush(%s/%s)\n",
 234                         dentry->d_parent->d_name.name,
 235                         dentry->d_name.name);
 236
 237         if ((file->f_mode & FMODE_WRITE) == 0)
 238                 return 0;
 239         nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
 240
 241         /* Flush writes to the server and return any errors */
 242         return nfs_do_fsync(ctx, inode);
 243 }
 244
 245 static ssize_t
 246 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
 247                 unsigned long nr_segs, loff_t pos)
 248 {
 249         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 250         struct inode * inode = dentry->d_inode;
 251         ssize_t result;
 252         size_t count = iov_length(iov, nr_segs);
 253
 254         if (iocb->ki_filp->f_flags & O_DIRECT)
 255                 return nfs_file_direct_read(iocb, iov, nr_segs, pos);
 256
 257         dprintk("NFS: read(%s/%s, %lu@%lu)\n",
 258                 dentry->d_parent->d_name.name, dentry->d_name.name,
 259                 (unsigned long) count, (unsigned long) pos);
 260
 261         result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
 262         nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
 263         if (!result)
 264                 result = generic_file_aio_read(iocb, iov, nr_segs, pos);
 265         return result;
 266 }
 267
 268 static ssize_t
 269 nfs_file_splice_read(struct file *filp, loff_t *ppos,
 270                      struct pipe_inode_info *pipe, size_t count,
 271                      unsigned int flags)
 272 {
 273         struct dentry *dentry = filp->f_path.dentry;
 274         struct inode *inode = dentry->d_inode;
 275         ssize_t res;
 276
 277         dprintk("NFS: splice_read(%s/%s, %lu@%Lu)\n",
 278                 dentry->d_parent->d_name.name, dentry->d_name.name,
 279                 (unsigned long) count, (unsigned long long) *ppos);
 280
 281         res = nfs_revalidate_mapping(inode, filp->f_mapping);
 282         if (!res)
 283                 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
 284         return res;
 285 }
 286
 287 static int
 288 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
 289 {
 290         struct dentry *dentry = file->f_path.dentry;
 291         struct inode *inode = dentry->d_inode;
 292         int     status;
 293
 294         dprintk("NFS: mmap(%s/%s)\n",
 295                 dentry->d_parent->d_name.name, dentry->d_name.name);
 296
 297         /* Note: generic_file_mmap() returns ENOSYS on nommu systems
 298          *       so we call that before revalidating the mapping
 299          */
 300         status = generic_file_mmap(file, vma);
 301         if (!status) {
 302                 vma->vm_ops = &nfs_file_vm_ops;
 303                 status = nfs_revalidate_mapping(inode, file->f_mapping);
 304         }
 305         return status;
 306 }
 307
 308 /*
 309  * Flush any dirty pages for this process, and check for write errors.
 310  * The return status from this call provides a reliable indication of
 311  * whether any write errors occurred for this process.
 312  */
 313 static int
 314 nfs_file_fsync(struct file *file, struct dentry *dentry, int datasync)
 315 {
 316         struct nfs_open_context *ctx = nfs_file_open_context(file);
 317         struct inode *inode = dentry->d_inode;
 318
 319         dprintk("NFS: fsync file(%s/%s) datasync %d\n",
 320                         dentry->d_parent->d_name.name, dentry->d_name.name,
 321                         datasync);
 322
 323         nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
 324         return nfs_do_fsync(ctx, inode);
 325 }
 326
 327 /*
 328  * This does the "real" work of the write. We must allocate and lock the
 329  * page to be sent back to the generic routine, which then copies the
 330  * data from user space.
 331  *
 332  * If the writer ends up delaying the write, the writer needs to
 333  * increment the page use counts until he is done with the page.
 334  */
 335 static int nfs_write_begin(struct file *file, struct address_space *mapping,
 336                         loff_t pos, unsigned len, unsigned flags,
 337                         struct page **pagep, void **fsdata)
 338 {
 339         int ret;
 340         pgoff_t index;
 341         struct page *page;
 342         index = pos >> PAGE_CACHE_SHIFT;
 343
 344         dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n",
 345                 file->f_path.dentry->d_parent->d_name.name,
 346                 file->f_path.dentry->d_name.name,
 347                 mapping->host->i_ino, len, (long long) pos);
 348
 349         /*
 350          * Prevent starvation issues if someone is doing a consistency
 351          * sync-to-disk
 352          */
 353         ret = wait_on_bit(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
 354                         nfs_wait_bit_killable, TASK_KILLABLE);
 355         if (ret)
 356                 return ret;
 357
 358         page = grab_cache_page_write_begin(mapping, index, flags);
 359         if (!page)
 360                 return -ENOMEM;
 361         *pagep = page;
 362
 363         ret = nfs_flush_incompatible(file, page);
 364         if (ret) {
 365                 unlock_page(page);
 366                 page_cache_release(page);
 367         }
 368         return ret;
 369 }
 370
 371 static int nfs_write_end(struct file *file, struct address_space *mapping,
 372                         loff_t pos, unsigned len, unsigned copied,
 373                         struct page *page, void *fsdata)
 374 {
 375         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 376         int status;
 377
 378         dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n",
 379                 file->f_path.dentry->d_parent->d_name.name,
 380                 file->f_path.dentry->d_name.name,
 381                 mapping->host->i_ino, len, (long long) pos);
 382
 383         /*
 384          * Zero any uninitialised parts of the page, and then mark the page
 385          * as up to date if it turns out that we're extending the file.
 386          */
 387         if (!PageUptodate(page)) {
 388                 unsigned pglen = nfs_page_length(page);
 389                 unsigned end = offset + len;
 390
 391                 if (pglen == 0) {
 392                         zero_user_segments(page, 0, offset,
 393                                         end, PAGE_CACHE_SIZE);
 394                         SetPageUptodate(page);
 395                 } else if (end >= pglen) {
 396                         zero_user_segment(page, end, PAGE_CACHE_SIZE);
 397                         if (offset == 0)
 398                                 SetPageUptodate(page);
 399                 } else
 400                         zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
 401         }
 402
 403         status = nfs_updatepage(file, page, offset, copied);
 404
 405         unlock_page(page);
 406         page_cache_release(page);
 407
 408         if (status < 0)
 409                 return status;
 410         return copied;
 411 }
 412
 413 /*
 414  * Partially or wholly invalidate a page
 415  * - Release the private state associated with a page if undergoing complete
 416  *   page invalidation
 417  * - Called if either PG_private or PG_fscache is set on the page
 418  * - Caller holds page lock
 419  */
 420 static void nfs_invalidate_page(struct page *page, unsigned long offset)
 421 {
 422         dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
 423
 424         if (offset != 0)
 425                 return;
 426         /* Cancel any unstarted writes on this page */
 427         nfs_wb_page_cancel(page->mapping->host, page);
 428
 429         nfs_fscache_invalidate_page(page, page->mapping->host);
 430 }
 431
 432 /*
 433  * Attempt to release the private state associated with a page
 434  * - Called if either PG_private or PG_fscache is set on the page
 435  * - Caller holds page lock
 436  * - Return true (may release page) or false (may not)
 437  */
 438 static int nfs_release_page(struct page *page, gfp_t gfp)
 439 {
 440         dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
 441
 442         /* If PagePrivate() is set, then the page is not freeable */
 443         if (PagePrivate(page))
 444                 return 0;
 445         return nfs_fscache_release_page(page, gfp);
 446 }
 447
 448 /*
 449  * Attempt to clear the private state associated with a page when an error
 450  * occurs that requires the cached contents of an inode to be written back or
 451  * destroyed
 452  * - Called if either PG_private or fscache is set on the page
 453  * - Caller holds page lock
 454  * - Return 0 if successful, -error otherwise
 455  */
 456 static int nfs_launder_page(struct page *page)
 457 {
 458         struct inode *inode = page->mapping->host;
 459         struct nfs_inode *nfsi = NFS_I(inode);
 460
 461         dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
 462                 inode->i_ino, (long long)page_offset(page));
 463
 464         nfs_fscache_wait_on_page_write(nfsi, page);
 465         return nfs_wb_page(inode, page);
 466 }
 467
 468 const struct address_space_operations nfs_file_aops = {
 469         .readpage = nfs_readpage,
 470         .readpages = nfs_readpages,
 471         .set_page_dirty = __set_page_dirty_nobuffers,
 472         .writepage = nfs_writepage,
 473         .writepages = nfs_writepages,
 474         .write_begin = nfs_write_begin,
 475         .write_end = nfs_write_end,
 476         .invalidatepage = nfs_invalidate_page,
 477         .releasepage = nfs_release_page,
 478         .direct_IO = nfs_direct_IO,
 479         .launder_page = nfs_launder_page,
 480 };
 481
 482 /*
 483  * Notification that a PTE pointing to an NFS page is about to be made
 484  * writable, implying that someone is about to modify the page through a
 485  * shared-writable mapping
 486  */
 487 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 488 {
 489         struct page *page = vmf->page;
 490         struct file *filp = vma->vm_file;
 491         struct dentry *dentry = filp->f_path.dentry;
 492         unsigned pagelen;
 493         int ret = -EINVAL;
 494         struct address_space *mapping;
 495
 496         dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n",
 497                 dentry->d_parent->d_name.name, dentry->d_name.name,
 498                 filp->f_mapping->host->i_ino,
 499                 (long long)page_offset(page));
 500
 501         /* make sure the cache has finished storing the page */
 502         nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);
 503
 504         lock_page(page);
 505         mapping = page->mapping;
 506         if (mapping != dentry->d_inode->i_mapping)
 507                 goto out_unlock;
 508
 509         ret = 0;
 510         pagelen = nfs_page_length(page);
 511         if (pagelen == 0)
 512                 goto out_unlock;
 513
 514         ret = nfs_flush_incompatible(filp, page);
 515         if (ret != 0)
 516                 goto out_unlock;
 517
 518         ret = nfs_updatepage(filp, page, 0, pagelen);
 519         if (ret == 0)
 520                 ret = pagelen;
 521 out_unlock:
 522         unlock_page(page);
 523         if (ret)
 524                 ret = VM_FAULT_SIGBUS;
 525         return ret;
 526 }
 527
 528 static struct vm_operations_struct nfs_file_vm_ops = {
 529         .fault = filemap_fault,
 530         .page_mkwrite = nfs_vm_page_mkwrite,
 531 };
 532
 533 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
 534 {
 535         struct nfs_open_context *ctx;
 536
 537         if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
 538                 return 1;
 539         ctx = nfs_file_open_context(filp);
 540         if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
 541                 return 1;
 542         return 0;
 543 }
 544
 545 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
 546                                 unsigned long nr_segs, loff_t pos)
 547 {
 548         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 549         struct inode * inode = dentry->d_inode;
 550         ssize_t result;
 551         size_t count = iov_length(iov, nr_segs);
 552
 553         if (iocb->ki_filp->f_flags & O_DIRECT)
 554                 return nfs_file_direct_write(iocb, iov, nr_segs, pos);
 555
 556         dprintk("NFS: write(%s/%s, %lu@%Ld)\n",
 557                 dentry->d_parent->d_name.name, dentry->d_name.name,
 558                 (unsigned long) count, (long long) pos);
 559
 560         result = -EBUSY;
 561         if (IS_SWAPFILE(inode))
 562                 goto out_swapfile;
 563         /*
 564          * O_APPEND implies that we must revalidate the file length.
 565          */
 566         if (iocb->ki_filp->f_flags & O_APPEND) {
 567                 result = nfs_revalidate_file_size(inode, iocb->ki_filp);
 568                 if (result)
 569                         goto out;
 570         }
 571
 572         result = count;
 573         if (!count)
 574                 goto out;
 575
 576         nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 577         result = generic_file_aio_write(iocb, iov, nr_segs, pos);
 578         /* Return error values for O_SYNC and IS_SYNC() */
 579         if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
 580                 int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
 581                 if (err < 0)
 582                         result = err;
 583         }
 584 out:
 585         return result;
 586
 587 out_swapfile:
 588         printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
 589         goto out;
 590 }
 591
 592 static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
 593 {
 594         struct inode *inode = filp->f_mapping->host;
 595         int status = 0;
 596
 597         lock_kernel();
 598         /* Try local locking first */
 599         posix_test_lock(filp, fl);
 600         if (fl->fl_type != F_UNLCK) {
 601                 /* found a conflict */
 602                 goto out;
 603         }
 604
 605         if (nfs_have_delegation(inode, FMODE_READ))
 606                 goto out_noconflict;
 607
 608         if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
 609                 goto out_noconflict;
 610
 611         status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 612 out:
 613         unlock_kernel();
 614         return status;
 615 out_noconflict:
 616         fl->fl_type = F_UNLCK;
 617         goto out;
 618 }
 619
 620 static int do_vfs_lock(struct file *file, struct file_lock *fl)
 621 {
 622         int res = 0;
 623         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 624                 case FL_POSIX:
 625                         res = posix_lock_file_wait(file, fl);
 626                         break;
 627                 case FL_FLOCK:
 628                         res = flock_lock_file_wait(file, fl);
 629                         break;
 630                 default:
 631                         BUG();
 632         }
 633         if (res < 0)
 634                 dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
 635                         " - error %d!\n",
 636                                 __func__, res);
 637         return res;
 638 }
 639
 640 static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
 641 {
 642         struct inode *inode = filp->f_mapping->host;
 643         int status;
 644
 645         /*
 646          * Flush all pending writes before doing anything
 647          * with locks..
 648          */
 649         nfs_sync_mapping(filp->f_mapping);
 650
 651         /* NOTE: special case
 652          *      If we're signalled while cleaning up locks on process exit, we
 653          *      still need to complete the unlock.
 654          */
 655         lock_kernel();
 656         /* Use local locking if mounted with "-onolock" */
 657         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 658                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 659         else
 660                 status = do_vfs_lock(filp, fl);
 661         unlock_kernel();
 662         return status;
 663 }
 664
 665 static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
 666 {
 667         struct inode *inode = filp->f_mapping->host;
 668         int status;
 669
 670         /*
 671          * Flush all pending writes before doing anything
 672          * with locks..
 673          */
 674         status = nfs_sync_mapping(filp->f_mapping);
 675         if (status != 0)
 676                 goto out;
 677
 678         lock_kernel();
 679         /* Use local locking if mounted with "-onolock" */
 680         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 681                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 682         else
 683                 status = do_vfs_lock(filp, fl);
 684         unlock_kernel();
 685         if (status < 0)
 686                 goto out;
 687         /*
 688          * Make sure we clear the cache whenever we try to get the lock.
 689          * This makes locking act as a cache coherency point.
 690          */
 691         nfs_sync_mapping(filp->f_mapping);
 692         if (!nfs_have_delegation(inode, FMODE_READ))
 693                 nfs_zap_caches(inode);
 694 out:
 695         return status;
 696 }
 697
 698 /*
 699  * Lock a (portion of) a file
 700  */
 701 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
 702 {
 703         struct inode *inode = filp->f_mapping->host;
 704         int ret = -ENOLCK;
 705
 706         dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n",
 707                         filp->f_path.dentry->d_parent->d_name.name,
 708                         filp->f_path.dentry->d_name.name,
 709                         fl->fl_type, fl->fl_flags,
 710                         (long long)fl->fl_start, (long long)fl->fl_end);
 711
 712         nfs_inc_stats(inode, NFSIOS_VFSLOCK);
 713
 714         /* No mandatory locks over NFS */
 715         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 716                 goto out_err;
 717
 718         if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
 719                 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
 720                 if (ret < 0)
 721                         goto out_err;
 722         }
 723
 724         if (IS_GETLK(cmd))
 725                 ret = do_getlk(filp, cmd, fl);
 726         else if (fl->fl_type == F_UNLCK)
 727                 ret = do_unlk(filp, cmd, fl);
 728         else
 729                 ret = do_setlk(filp, cmd, fl);
 730 out_err:
 731         return ret;
 732 }
 733
 734 /*
 735  * Lock a (portion of) a file
 736  */
 737 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
 738 {
 739         dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n",
 740                         filp->f_path.dentry->d_parent->d_name.name,
 741                         filp->f_path.dentry->d_name.name,
 742                         fl->fl_type, fl->fl_flags);
 743
 744         if (!(fl->fl_flags & FL_FLOCK))
 745                 return -ENOLCK;
 746
 747         /* We're simulating flock() locks using posix locks on the server */
 748         fl->fl_owner = (fl_owner_t)filp;
 749         fl->fl_start = 0;
 750         fl->fl_end = OFFSET_MAX;
 751
 752         if (fl->fl_type == F_UNLCK)
 753                 return do_unlk(filp, cmd, fl);
 754         return do_setlk(filp, cmd, fl);
 755 }
 756
 757 /*
 758  * There is no protocol support for leases, so we have no way to implement
 759  * them correctly in the face of opens by other clients.
 760  */
 761 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
 762 {
 763         dprintk("NFS: setlease(%s/%s, arg=%ld)\n",
 764                         file->f_path.dentry->d_parent->d_name.name,
 765                         file->f_path.dentry->d_name.name, arg);
 766
 767         return -EINVAL;
 768 }