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_splice_write(struct pipe_inode_info *pipe,
  52                                         struct file *filp, loff_t *ppos,
  53                                         size_t count, unsigned int flags);
  54 static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
  55                                 unsigned long nr_segs, loff_t pos);
  56 static int  nfs_file_flush(struct file *, fl_owner_t id);
  57 static int  nfs_file_fsync(struct file *, struct dentry *dentry, int datasync);
  58 static int nfs_check_flags(int flags);
  59 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
  60 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
  61 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);
  62
  63 static struct vm_operations_struct nfs_file_vm_ops;
  64
  65 const struct file_operations nfs_file_operations = {
  66         .llseek         = nfs_file_llseek,
  67         .read           = do_sync_read,
  68         .write          = do_sync_write,
  69         .aio_read       = nfs_file_read,
  70         .aio_write      = nfs_file_write,
  71         .mmap           = nfs_file_mmap,
  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         .splice_write   = nfs_file_splice_write,
  80         .check_flags    = nfs_check_flags,
  81         .setlease       = nfs_setlease,
  82 };
  83
  84 const struct inode_operations nfs_file_inode_operations = {
  85         .permission     = nfs_permission,
  86         .getattr        = nfs_getattr,
  87         .setattr        = nfs_setattr,
  88 };
  89
  90 #ifdef CONFIG_NFS_V3
  91 const struct inode_operations nfs3_file_inode_operations = {
  92         .permission     = nfs_permission,
  93         .getattr        = nfs_getattr,
  94         .setattr        = nfs_setattr,
  95         .listxattr      = nfs3_listxattr,
  96         .getxattr       = nfs3_getxattr,
  97         .setxattr       = nfs3_setxattr,
  98         .removexattr    = nfs3_removexattr,
  99 };
 100 #endif  /* CONFIG_NFS_v3 */
 101
 102 /* Hack for future NFS swap support */
 103 #ifndef IS_SWAPFILE
 104 # define IS_SWAPFILE(inode)     (0)
 105 #endif
 106
 107 static int nfs_check_flags(int flags)
 108 {
 109         if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
 110                 return -EINVAL;
 111
 112         return 0;
 113 }
 114
 115 /*
 116  * Open file
 117  */
 118 static int
 119 nfs_file_open(struct inode *inode, struct file *filp)
 120 {
 121         int res;
 122
 123         dprintk("NFS: open file(%s/%s)\n",
 124                         filp->f_path.dentry->d_parent->d_name.name,
 125                         filp->f_path.dentry->d_name.name);
 126
 127         res = nfs_check_flags(filp->f_flags);
 128         if (res)
 129                 return res;
 130
 131         nfs_inc_stats(inode, NFSIOS_VFSOPEN);
 132         res = nfs_open(inode, filp);
 133         return res;
 134 }
 135
 136 static int
 137 nfs_file_release(struct inode *inode, struct file *filp)
 138 {
 139         struct dentry *dentry = filp->f_path.dentry;
 140
 141         dprintk("NFS: release(%s/%s)\n",
 142                         dentry->d_parent->d_name.name,
 143                         dentry->d_name.name);
 144
 145         nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
 146         return nfs_release(inode, filp);
 147 }
 148
 149 /**
 150  * nfs_revalidate_size - Revalidate the file size
 151  * @inode - pointer to inode struct
 152  * @file - pointer to struct file
 153  *
 154  * Revalidates the file length. This is basically a wrapper around
 155  * nfs_revalidate_inode() that takes into account the fact that we may
 156  * have cached writes (in which case we don't care about the server's
 157  * idea of what the file length is), or O_DIRECT (in which case we
 158  * shouldn't trust the cache).
 159  */
 160 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
 161 {
 162         struct nfs_server *server = NFS_SERVER(inode);
 163         struct nfs_inode *nfsi = NFS_I(inode);
 164
 165         if (server->flags & NFS_MOUNT_NOAC)
 166                 goto force_reval;
 167         if (filp->f_flags & O_DIRECT)
 168                 goto force_reval;
 169         if (nfsi->npages != 0)
 170                 return 0;
 171         if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
 172                 return 0;
 173 force_reval:
 174         return __nfs_revalidate_inode(server, inode);
 175 }
 176
 177 static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
 178 {
 179         loff_t loff;
 180
 181         dprintk("NFS: llseek file(%s/%s, %lld, %d)\n",
 182                         filp->f_path.dentry->d_parent->d_name.name,
 183                         filp->f_path.dentry->d_name.name,
 184                         offset, origin);
 185
 186         /* origin == SEEK_END => we must revalidate the cached file length */
 187         if (origin == SEEK_END) {
 188                 struct inode *inode = filp->f_mapping->host;
 189
 190                 int retval = nfs_revalidate_file_size(inode, filp);
 191                 if (retval < 0)
 192                         return (loff_t)retval;
 193
 194                 spin_lock(&inode->i_lock);
 195                 loff = generic_file_llseek_unlocked(filp, offset, origin);
 196                 spin_unlock(&inode->i_lock);
 197         } else
 198                 loff = generic_file_llseek_unlocked(filp, offset, origin);
 199         return loff;
 200 }
 201
 202 /*
 203  * Helper for nfs_file_flush() and nfs_file_fsync()
 204  *
 205  * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
 206  * disk, but it retrieves and clears ctx->error after synching, despite
 207  * the two being set at the same time in nfs_context_set_write_error().
 208  * This is because the former is used to notify the _next_ call to
 209  * nfs_file_write() that a write error occured, and hence cause it to
 210  * fall back to doing a synchronous write.
 211  */
 212 static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
 213 {
 214         int have_error, status;
 215         int ret = 0;
 216
 217         have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 218         status = nfs_wb_all(inode);
 219         have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 220         if (have_error)
 221                 ret = xchg(&ctx->error, 0);
 222         if (!ret)
 223                 ret = status;
 224         return ret;
 225 }
 226
 227 /*
 228  * Flush all dirty pages, and check for write errors.
 229  */
 230 static int
 231 nfs_file_flush(struct file *file, fl_owner_t id)
 232 {
 233         struct nfs_open_context *ctx = nfs_file_open_context(file);
 234         struct dentry   *dentry = file->f_path.dentry;
 235         struct inode    *inode = dentry->d_inode;
 236
 237         dprintk("NFS: flush(%s/%s)\n",
 238                         dentry->d_parent->d_name.name,
 239                         dentry->d_name.name);
 240
 241         if ((file->f_mode & FMODE_WRITE) == 0)
 242                 return 0;
 243         nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
 244
 245         /* Flush writes to the server and return any errors */
 246         return nfs_do_fsync(ctx, inode);
 247 }
 248
 249 static ssize_t
 250 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
 251                 unsigned long nr_segs, loff_t pos)
 252 {
 253         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 254         struct inode * inode = dentry->d_inode;
 255         ssize_t result;
 256         size_t count = iov_length(iov, nr_segs);
 257
 258         if (iocb->ki_filp->f_flags & O_DIRECT)
 259                 return nfs_file_direct_read(iocb, iov, nr_segs, pos);
 260
 261         dprintk("NFS: read(%s/%s, %lu@%lu)\n",
 262                 dentry->d_parent->d_name.name, dentry->d_name.name,
 263                 (unsigned long) count, (unsigned long) pos);
 264
 265         result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
 266         nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
 267         if (!result)
 268                 result = generic_file_aio_read(iocb, iov, nr_segs, pos);
 269         return result;
 270 }
 271
 272 static ssize_t
 273 nfs_file_splice_read(struct file *filp, loff_t *ppos,
 274                      struct pipe_inode_info *pipe, size_t count,
 275                      unsigned int flags)
 276 {
 277         struct dentry *dentry = filp->f_path.dentry;
 278         struct inode *inode = dentry->d_inode;
 279         ssize_t res;
 280
 281         dprintk("NFS: splice_read(%s/%s, %lu@%Lu)\n",
 282                 dentry->d_parent->d_name.name, dentry->d_name.name,
 283                 (unsigned long) count, (unsigned long long) *ppos);
 284
 285         res = nfs_revalidate_mapping(inode, filp->f_mapping);
 286         if (!res)
 287                 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
 288         return res;
 289 }
 290
 291 static int
 292 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
 293 {
 294         struct dentry *dentry = file->f_path.dentry;
 295         struct inode *inode = dentry->d_inode;
 296         int     status;
 297
 298         dprintk("NFS: mmap(%s/%s)\n",
 299                 dentry->d_parent->d_name.name, dentry->d_name.name);
 300
 301         /* Note: generic_file_mmap() returns ENOSYS on nommu systems
 302          *       so we call that before revalidating the mapping
 303          */
 304         status = generic_file_mmap(file, vma);
 305         if (!status) {
 306                 vma->vm_ops = &nfs_file_vm_ops;
 307                 status = nfs_revalidate_mapping(inode, file->f_mapping);
 308         }
 309         return status;
 310 }
 311
 312 /*
 313  * Flush any dirty pages for this process, and check for write errors.
 314  * The return status from this call provides a reliable indication of
 315  * whether any write errors occurred for this process.
 316  */
 317 static int
 318 nfs_file_fsync(struct file *file, struct dentry *dentry, int datasync)
 319 {
 320         struct nfs_open_context *ctx = nfs_file_open_context(file);
 321         struct inode *inode = dentry->d_inode;
 322
 323         dprintk("NFS: fsync file(%s/%s) datasync %d\n",
 324                         dentry->d_parent->d_name.name, dentry->d_name.name,
 325                         datasync);
 326
 327         nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
 328         return nfs_do_fsync(ctx, inode);
 329 }
 330
 331 /*
 332  * This does the "real" work of the write. We must allocate and lock the
 333  * page to be sent back to the generic routine, which then copies the
 334  * data from user space.
 335  *
 336  * If the writer ends up delaying the write, the writer needs to
 337  * increment the page use counts until he is done with the page.
 338  */
 339 static int nfs_write_begin(struct file *file, struct address_space *mapping,
 340                         loff_t pos, unsigned len, unsigned flags,
 341                         struct page **pagep, void **fsdata)
 342 {
 343         int ret;
 344         pgoff_t index;
 345         struct page *page;
 346         index = pos >> PAGE_CACHE_SHIFT;
 347
 348         dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n",
 349                 file->f_path.dentry->d_parent->d_name.name,
 350                 file->f_path.dentry->d_name.name,
 351                 mapping->host->i_ino, len, (long long) pos);
 352
 353         /*
 354          * Prevent starvation issues if someone is doing a consistency
 355          * sync-to-disk
 356          */
 357         ret = wait_on_bit(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
 358                         nfs_wait_bit_killable, TASK_KILLABLE);
 359         if (ret)
 360                 return ret;
 361
 362         page = grab_cache_page_write_begin(mapping, index, flags);
 363         if (!page)
 364                 return -ENOMEM;
 365         *pagep = page;
 366
 367         ret = nfs_flush_incompatible(file, page);
 368         if (ret) {
 369                 unlock_page(page);
 370                 page_cache_release(page);
 371         }
 372         return ret;
 373 }
 374
 375 static int nfs_write_end(struct file *file, struct address_space *mapping,
 376                         loff_t pos, unsigned len, unsigned copied,
 377                         struct page *page, void *fsdata)
 378 {
 379         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 380         int status;
 381
 382         dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n",
 383                 file->f_path.dentry->d_parent->d_name.name,
 384                 file->f_path.dentry->d_name.name,
 385                 mapping->host->i_ino, len, (long long) pos);
 386
 387         /*
 388          * Zero any uninitialised parts of the page, and then mark the page
 389          * as up to date if it turns out that we're extending the file.
 390          */
 391         if (!PageUptodate(page)) {
 392                 unsigned pglen = nfs_page_length(page);
 393                 unsigned end = offset + len;
 394
 395                 if (pglen == 0) {
 396                         zero_user_segments(page, 0, offset,
 397                                         end, PAGE_CACHE_SIZE);
 398                         SetPageUptodate(page);
 399                 } else if (end >= pglen) {
 400                         zero_user_segment(page, end, PAGE_CACHE_SIZE);
 401                         if (offset == 0)
 402                                 SetPageUptodate(page);
 403                 } else
 404                         zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
 405         }
 406
 407         status = nfs_updatepage(file, page, offset, copied);
 408
 409         unlock_page(page);
 410         page_cache_release(page);
 411
 412         if (status < 0)
 413                 return status;
 414         return copied;
 415 }
 416
 417 /*
 418  * Partially or wholly invalidate a page
 419  * - Release the private state associated with a page if undergoing complete
 420  *   page invalidation
 421  * - Called if either PG_private or PG_fscache is set on the page
 422  * - Caller holds page lock
 423  */
 424 static void nfs_invalidate_page(struct page *page, unsigned long offset)
 425 {
 426         dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
 427
 428         if (offset != 0)
 429                 return;
 430         /* Cancel any unstarted writes on this page */
 431         nfs_wb_page_cancel(page->mapping->host, page);
 432
 433         nfs_fscache_invalidate_page(page, page->mapping->host);
 434 }
 435
 436 /*
 437  * Attempt to release the private state associated with a page
 438  * - Called if either PG_private or PG_fscache is set on the page
 439  * - Caller holds page lock
 440  * - Return true (may release page) or false (may not)
 441  */
 442 static int nfs_release_page(struct page *page, gfp_t gfp)
 443 {
 444         dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
 445
 446         /* If PagePrivate() is set, then the page is not freeable */
 447         if (PagePrivate(page))
 448                 return 0;
 449         return nfs_fscache_release_page(page, gfp);
 450 }
 451
 452 /*
 453  * Attempt to clear the private state associated with a page when an error
 454  * occurs that requires the cached contents of an inode to be written back or
 455  * destroyed
 456  * - Called if either PG_private or fscache is set on the page
 457  * - Caller holds page lock
 458  * - Return 0 if successful, -error otherwise
 459  */
 460 static int nfs_launder_page(struct page *page)
 461 {
 462         struct inode *inode = page->mapping->host;
 463         struct nfs_inode *nfsi = NFS_I(inode);
 464
 465         dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
 466                 inode->i_ino, (long long)page_offset(page));
 467
 468         nfs_fscache_wait_on_page_write(nfsi, page);
 469         return nfs_wb_page(inode, page);
 470 }
 471
 472 const struct address_space_operations nfs_file_aops = {
 473         .readpage = nfs_readpage,
 474         .readpages = nfs_readpages,
 475         .set_page_dirty = __set_page_dirty_nobuffers,
 476         .writepage = nfs_writepage,
 477         .writepages = nfs_writepages,
 478         .write_begin = nfs_write_begin,
 479         .write_end = nfs_write_end,
 480         .invalidatepage = nfs_invalidate_page,
 481         .releasepage = nfs_release_page,
 482         .direct_IO = nfs_direct_IO,
 483         .launder_page = nfs_launder_page,
 484 };
 485
 486 /*
 487  * Notification that a PTE pointing to an NFS page is about to be made
 488  * writable, implying that someone is about to modify the page through a
 489  * shared-writable mapping
 490  */
 491 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 492 {
 493         struct page *page = vmf->page;
 494         struct file *filp = vma->vm_file;
 495         struct dentry *dentry = filp->f_path.dentry;
 496         unsigned pagelen;
 497         int ret = -EINVAL;
 498         struct address_space *mapping;
 499
 500         dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n",
 501                 dentry->d_parent->d_name.name, dentry->d_name.name,
 502                 filp->f_mapping->host->i_ino,
 503                 (long long)page_offset(page));
 504
 505         /* make sure the cache has finished storing the page */
 506         nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);
 507
 508         lock_page(page);
 509         mapping = page->mapping;
 510         if (mapping != dentry->d_inode->i_mapping)
 511                 goto out_unlock;
 512
 513         ret = 0;
 514         pagelen = nfs_page_length(page);
 515         if (pagelen == 0)
 516                 goto out_unlock;
 517
 518         ret = nfs_flush_incompatible(filp, page);
 519         if (ret != 0)
 520                 goto out_unlock;
 521
 522         ret = nfs_updatepage(filp, page, 0, pagelen);
 523 out_unlock:
 524         if (!ret)
 525                 return VM_FAULT_LOCKED;
 526         unlock_page(page);
 527         return VM_FAULT_SIGBUS;
 528 }
 529
 530 static struct vm_operations_struct nfs_file_vm_ops = {
 531         .fault = filemap_fault,
 532         .page_mkwrite = nfs_vm_page_mkwrite,
 533 };
 534
 535 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
 536 {
 537         struct nfs_open_context *ctx;
 538
 539         if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
 540                 return 1;
 541         ctx = nfs_file_open_context(filp);
 542         if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
 543                 return 1;
 544         return 0;
 545 }
 546
 547 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
 548                                 unsigned long nr_segs, loff_t pos)
 549 {
 550         struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 551         struct inode * inode = dentry->d_inode;
 552         ssize_t result;
 553         size_t count = iov_length(iov, nr_segs);
 554
 555         if (iocb->ki_filp->f_flags & O_DIRECT)
 556                 return nfs_file_direct_write(iocb, iov, nr_segs, pos);
 557
 558         dprintk("NFS: write(%s/%s, %lu@%Ld)\n",
 559                 dentry->d_parent->d_name.name, dentry->d_name.name,
 560                 (unsigned long) count, (long long) pos);
 561
 562         result = -EBUSY;
 563         if (IS_SWAPFILE(inode))
 564                 goto out_swapfile;
 565         /*
 566          * O_APPEND implies that we must revalidate the file length.
 567          */
 568         if (iocb->ki_filp->f_flags & O_APPEND) {
 569                 result = nfs_revalidate_file_size(inode, iocb->ki_filp);
 570                 if (result)
 571                         goto out;
 572         }
 573
 574         result = count;
 575         if (!count)
 576                 goto out;
 577
 578         nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 579         result = generic_file_aio_write(iocb, iov, nr_segs, pos);
 580         /* Return error values for O_SYNC and IS_SYNC() */
 581         if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
 582                 int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
 583                 if (err < 0)
 584                         result = err;
 585         }
 586 out:
 587         return result;
 588
 589 out_swapfile:
 590         printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
 591         goto out;
 592 }
 593
 594 static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
 595                                      struct file *filp, loff_t *ppos,
 596                                      size_t count, unsigned int flags)
 597 {
 598         struct dentry *dentry = filp->f_path.dentry;
 599         struct inode *inode = dentry->d_inode;
 600         ssize_t ret;
 601
 602         dprintk("NFS splice_write(%s/%s, %lu@%llu)\n",
 603                 dentry->d_parent->d_name.name, dentry->d_name.name,
 604                 (unsigned long) count, (unsigned long long) *ppos);
 605
 606         /*
 607          * The combination of splice and an O_APPEND destination is disallowed.
 608          */
 609
 610         nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 611
 612         ret = generic_file_splice_write(pipe, filp, ppos, count, flags);
 613         if (ret >= 0 && nfs_need_sync_write(filp, inode)) {
 614                 int err = nfs_do_fsync(nfs_file_open_context(filp), inode);
 615                 if (err < 0)
 616                         ret = err;
 617         }
 618         return ret;
 619 }
 620
 621 static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
 622 {
 623         struct inode *inode = filp->f_mapping->host;
 624         int status = 0;
 625
 626         /* Try local locking first */
 627         posix_test_lock(filp, fl);
 628         if (fl->fl_type != F_UNLCK) {
 629                 /* found a conflict */
 630                 goto out;
 631         }
 632
 633         if (nfs_have_delegation(inode, FMODE_READ))
 634                 goto out_noconflict;
 635
 636         if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
 637                 goto out_noconflict;
 638
 639         status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 640 out:
 641         return status;
 642 out_noconflict:
 643         fl->fl_type = F_UNLCK;
 644         goto out;
 645 }
 646
 647 static int do_vfs_lock(struct file *file, struct file_lock *fl)
 648 {
 649         int res = 0;
 650         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 651                 case FL_POSIX:
 652                         res = posix_lock_file_wait(file, fl);
 653                         break;
 654                 case FL_FLOCK:
 655                         res = flock_lock_file_wait(file, fl);
 656                         break;
 657                 default:
 658                         BUG();
 659         }
 660         if (res < 0)
 661                 dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
 662                         " - error %d!\n",
 663                                 __func__, res);
 664         return res;
 665 }
 666
 667 static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
 668 {
 669         struct inode *inode = filp->f_mapping->host;
 670         int status;
 671
 672         /*
 673          * Flush all pending writes before doing anything
 674          * with locks..
 675          */
 676         nfs_sync_mapping(filp->f_mapping);
 677
 678         /* NOTE: special case
 679          *      If we're signalled while cleaning up locks on process exit, we
 680          *      still need to complete the unlock.
 681          */
 682         /* Use local locking if mounted with "-onolock" */
 683         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 684                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 685         else
 686                 status = do_vfs_lock(filp, fl);
 687         return status;
 688 }
 689
 690 static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
 691 {
 692         struct inode *inode = filp->f_mapping->host;
 693         int status;
 694
 695         /*
 696          * Flush all pending writes before doing anything
 697          * with locks..
 698          */
 699         status = nfs_sync_mapping(filp->f_mapping);
 700         if (status != 0)
 701                 goto out;
 702
 703         /* Use local locking if mounted with "-onolock" */
 704         if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
 705                 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 706         else
 707                 status = do_vfs_lock(filp, fl);
 708         if (status < 0)
 709                 goto out;
 710         /*
 711          * Make sure we clear the cache whenever we try to get the lock.
 712          * This makes locking act as a cache coherency point.
 713          */
 714         nfs_sync_mapping(filp->f_mapping);
 715         if (!nfs_have_delegation(inode, FMODE_READ))
 716                 nfs_zap_caches(inode);
 717 out:
 718         return status;
 719 }
 720
 721 /*
 722  * Lock a (portion of) a file
 723  */
 724 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
 725 {
 726         struct inode *inode = filp->f_mapping->host;
 727         int ret = -ENOLCK;
 728
 729         dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n",
 730                         filp->f_path.dentry->d_parent->d_name.name,
 731                         filp->f_path.dentry->d_name.name,
 732                         fl->fl_type, fl->fl_flags,
 733                         (long long)fl->fl_start, (long long)fl->fl_end);
 734
 735         nfs_inc_stats(inode, NFSIOS_VFSLOCK);
 736
 737         /* No mandatory locks over NFS */
 738         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 739                 goto out_err;
 740
 741         if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
 742                 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
 743                 if (ret < 0)
 744                         goto out_err;
 745         }
 746
 747         if (IS_GETLK(cmd))
 748                 ret = do_getlk(filp, cmd, fl);
 749         else if (fl->fl_type == F_UNLCK)
 750                 ret = do_unlk(filp, cmd, fl);
 751         else
 752                 ret = do_setlk(filp, cmd, fl);
 753 out_err:
 754         return ret;
 755 }
 756
 757 /*
 758  * Lock a (portion of) a file
 759  */
 760 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
 761 {
 762         dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n",
 763                         filp->f_path.dentry->d_parent->d_name.name,
 764                         filp->f_path.dentry->d_name.name,
 765                         fl->fl_type, fl->fl_flags);
 766
 767         if (!(fl->fl_flags & FL_FLOCK))
 768                 return -ENOLCK;
 769
 770         /* We're simulating flock() locks using posix locks on the server */
 771         fl->fl_owner = (fl_owner_t)filp;
 772         fl->fl_start = 0;
 773         fl->fl_end = OFFSET_MAX;
 774
 775         if (fl->fl_type == F_UNLCK)
 776                 return do_unlk(filp, cmd, fl);
 777         return do_setlk(filp, cmd, fl);
 778 }
 779
 780 /*
 781  * There is no protocol support for leases, so we have no way to implement
 782  * them correctly in the face of opens by other clients.
 783  */
 784 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
 785 {
 786         dprintk("NFS: setlease(%s/%s, arg=%ld)\n",
 787                         file->f_path.dentry->d_parent->d_name.name,
 788                         file->f_path.dentry->d_name.name, arg);
 789
 790         return -EINVAL;
 791 }