fs/fuse/file.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2006  Miklos Szeredi <miklos@szeredi.hu>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/pagemap.h>
  12 #include <linux/slab.h>
  13 #include <linux/kernel.h>
  14
  15 static const struct file_operations fuse_direct_io_file_operations;
  16
  17 static int fuse_send_open(struct inode *inode, struct file *file, int isdir,
  18                           struct fuse_open_out *outargp)
  19 {
  20         struct fuse_conn *fc = get_fuse_conn(inode);
  21         struct fuse_open_in inarg;
  22         struct fuse_req *req;
  23         int err;
  24
  25         req = fuse_get_req(fc);
  26         if (IS_ERR(req))
  27                 return PTR_ERR(req);
  28
  29         memset(&inarg, 0, sizeof(inarg));
  30         inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
  31         req->in.h.opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
  32         req->in.h.nodeid = get_node_id(inode);
  33         req->inode = inode;
  34         req->in.numargs = 1;
  35         req->in.args[0].size = sizeof(inarg);
  36         req->in.args[0].value = &inarg;
  37         req->out.numargs = 1;
  38         req->out.args[0].size = sizeof(*outargp);
  39         req->out.args[0].value = outargp;
  40         request_send(fc, req);
  41         err = req->out.h.error;
  42         fuse_put_request(fc, req);
  43
  44         return err;
  45 }
  46
  47 struct fuse_file *fuse_file_alloc(void)
  48 {
  49         struct fuse_file *ff;
  50         ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
  51         if (ff) {
  52                 ff->release_req = fuse_request_alloc();
  53                 if (!ff->release_req) {
  54                         kfree(ff);
  55                         ff = NULL;
  56                 }
  57         }
  58         return ff;
  59 }
  60
  61 void fuse_file_free(struct fuse_file *ff)
  62 {
  63         fuse_request_free(ff->release_req);
  64         kfree(ff);
  65 }
  66
  67 void fuse_finish_open(struct inode *inode, struct file *file,
  68                       struct fuse_file *ff, struct fuse_open_out *outarg)
  69 {
  70         if (outarg->open_flags & FOPEN_DIRECT_IO)
  71                 file->f_op = &fuse_direct_io_file_operations;
  72         if (!(outarg->open_flags & FOPEN_KEEP_CACHE))
  73                 invalidate_inode_pages(inode->i_mapping);
  74         ff->fh = outarg->fh;
  75         file->private_data = ff;
  76 }
  77
  78 int fuse_open_common(struct inode *inode, struct file *file, int isdir)
  79 {
  80         struct fuse_open_out outarg;
  81         struct fuse_file *ff;
  82         int err;
  83
  84         /* VFS checks this, but only _after_ ->open() */
  85         if (file->f_flags & O_DIRECT)
  86                 return -EINVAL;
  87
  88         err = generic_file_open(inode, file);
  89         if (err)
  90                 return err;
  91
  92         /* If opening the root node, no lookup has been performed on
  93            it, so the attributes must be refreshed */
  94         if (get_node_id(inode) == FUSE_ROOT_ID) {
  95                 err = fuse_do_getattr(inode);
  96                 if (err)
  97                         return err;
  98         }
  99
 100         ff = fuse_file_alloc();
 101         if (!ff)
 102                 return -ENOMEM;
 103
 104         err = fuse_send_open(inode, file, isdir, &outarg);
 105         if (err)
 106                 fuse_file_free(ff);
 107         else {
 108                 if (isdir)
 109                         outarg.open_flags &= ~FOPEN_DIRECT_IO;
 110                 fuse_finish_open(inode, file, ff, &outarg);
 111         }
 112
 113         return err;
 114 }
 115
 116 /* Special case for failed iget in CREATE */
 117 static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
 118 {
 119         /* If called from end_io_requests(), req has more than one
 120            reference and fuse_reset_request() cannot work */
 121         if (fc->connected) {
 122                 u64 nodeid = req->in.h.nodeid;
 123                 fuse_reset_request(req);
 124                 fuse_send_forget(fc, req, nodeid, 1);
 125         } else
 126                 fuse_put_request(fc, req);
 127 }
 128
 129 void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff,
 130                        u64 nodeid, struct inode *inode, int flags, int isdir)
 131 {
 132         struct fuse_req * req = ff->release_req;
 133         struct fuse_release_in *inarg = &req->misc.release_in;
 134
 135         inarg->fh = ff->fh;
 136         inarg->flags = flags;
 137         req->in.h.opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
 138         req->in.h.nodeid = nodeid;
 139         req->inode = inode;
 140         req->in.numargs = 1;
 141         req->in.args[0].size = sizeof(struct fuse_release_in);
 142         req->in.args[0].value = inarg;
 143         request_send_background(fc, req);
 144         if (!inode)
 145                 req->end = fuse_release_end;
 146         kfree(ff);
 147 }
 148
 149 int fuse_release_common(struct inode *inode, struct file *file, int isdir)
 150 {
 151         struct fuse_file *ff = file->private_data;
 152         if (ff) {
 153                 struct fuse_conn *fc = get_fuse_conn(inode);
 154                 u64 nodeid = get_node_id(inode);
 155                 fuse_send_release(fc, ff, nodeid, inode, file->f_flags, isdir);
 156         }
 157
 158         /* Return value is ignored by VFS */
 159         return 0;
 160 }
 161
 162 static int fuse_open(struct inode *inode, struct file *file)
 163 {
 164         return fuse_open_common(inode, file, 0);
 165 }
 166
 167 static int fuse_release(struct inode *inode, struct file *file)
 168 {
 169         return fuse_release_common(inode, file, 0);
 170 }
 171
 172 static int fuse_flush(struct file *file)
 173 {
 174         struct inode *inode = file->f_dentry->d_inode;
 175         struct fuse_conn *fc = get_fuse_conn(inode);
 176         struct fuse_file *ff = file->private_data;
 177         struct fuse_req *req;
 178         struct fuse_flush_in inarg;
 179         int err;
 180
 181         if (is_bad_inode(inode))
 182                 return -EIO;
 183
 184         if (fc->no_flush)
 185                 return 0;
 186
 187         req = fuse_get_req(fc);
 188         if (IS_ERR(req))
 189                 return PTR_ERR(req);
 190
 191         memset(&inarg, 0, sizeof(inarg));
 192         inarg.fh = ff->fh;
 193         req->in.h.opcode = FUSE_FLUSH;
 194         req->in.h.nodeid = get_node_id(inode);
 195         req->inode = inode;
 196         req->file = file;
 197         req->in.numargs = 1;
 198         req->in.args[0].size = sizeof(inarg);
 199         req->in.args[0].value = &inarg;
 200         request_send(fc, req);
 201         err = req->out.h.error;
 202         fuse_put_request(fc, req);
 203         if (err == -ENOSYS) {
 204                 fc->no_flush = 1;
 205                 err = 0;
 206         }
 207         return err;
 208 }
 209
 210 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
 211                       int isdir)
 212 {
 213         struct inode *inode = de->d_inode;
 214         struct fuse_conn *fc = get_fuse_conn(inode);
 215         struct fuse_file *ff = file->private_data;
 216         struct fuse_req *req;
 217         struct fuse_fsync_in inarg;
 218         int err;
 219
 220         if (is_bad_inode(inode))
 221                 return -EIO;
 222
 223         if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
 224                 return 0;
 225
 226         req = fuse_get_req(fc);
 227         if (IS_ERR(req))
 228                 return PTR_ERR(req);
 229
 230         memset(&inarg, 0, sizeof(inarg));
 231         inarg.fh = ff->fh;
 232         inarg.fsync_flags = datasync ? 1 : 0;
 233         req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
 234         req->in.h.nodeid = get_node_id(inode);
 235         req->inode = inode;
 236         req->file = file;
 237         req->in.numargs = 1;
 238         req->in.args[0].size = sizeof(inarg);
 239         req->in.args[0].value = &inarg;
 240         request_send(fc, req);
 241         err = req->out.h.error;
 242         fuse_put_request(fc, req);
 243         if (err == -ENOSYS) {
 244                 if (isdir)
 245                         fc->no_fsyncdir = 1;
 246                 else
 247                         fc->no_fsync = 1;
 248                 err = 0;
 249         }
 250         return err;
 251 }
 252
 253 static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
 254 {
 255         return fuse_fsync_common(file, de, datasync, 0);
 256 }
 257
 258 void fuse_read_fill(struct fuse_req *req, struct file *file,
 259                     struct inode *inode, loff_t pos, size_t count, int opcode)
 260 {
 261         struct fuse_file *ff = file->private_data;
 262         struct fuse_read_in *inarg = &req->misc.read_in;
 263
 264         inarg->fh = ff->fh;
 265         inarg->offset = pos;
 266         inarg->size = count;
 267         req->in.h.opcode = opcode;
 268         req->in.h.nodeid = get_node_id(inode);
 269         req->inode = inode;
 270         req->file = file;
 271         req->in.numargs = 1;
 272         req->in.args[0].size = sizeof(struct fuse_read_in);
 273         req->in.args[0].value = inarg;
 274         req->out.argpages = 1;
 275         req->out.argvar = 1;
 276         req->out.numargs = 1;
 277         req->out.args[0].size = count;
 278 }
 279
 280 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
 281                              struct inode *inode, loff_t pos, size_t count)
 282 {
 283         struct fuse_conn *fc = get_fuse_conn(inode);
 284         fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
 285         request_send(fc, req);
 286         return req->out.args[0].size;
 287 }
 288
 289 static int fuse_readpage(struct file *file, struct page *page)
 290 {
 291         struct inode *inode = page->mapping->host;
 292         struct fuse_conn *fc = get_fuse_conn(inode);
 293         struct fuse_req *req;
 294         int err;
 295
 296         err = -EIO;
 297         if (is_bad_inode(inode))
 298                 goto out;
 299
 300         req = fuse_get_req(fc);
 301         err = PTR_ERR(req);
 302         if (IS_ERR(req))
 303                 goto out;
 304
 305         req->out.page_zeroing = 1;
 306         req->num_pages = 1;
 307         req->pages[0] = page;
 308         fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE);
 309         err = req->out.h.error;
 310         fuse_put_request(fc, req);
 311         if (!err)
 312                 SetPageUptodate(page);
 313         fuse_invalidate_attr(inode); /* atime changed */
 314  out:
 315         unlock_page(page);
 316         return err;
 317 }
 318
 319 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 320 {
 321         int i;
 322
 323         fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */
 324
 325         for (i = 0; i < req->num_pages; i++) {
 326                 struct page *page = req->pages[i];
 327                 if (!req->out.h.error)
 328                         SetPageUptodate(page);
 329                 else
 330                         SetPageError(page);
 331                 unlock_page(page);
 332         }
 333         fuse_put_request(fc, req);
 334 }
 335
 336 static void fuse_send_readpages(struct fuse_req *req, struct file *file,
 337                                 struct inode *inode)
 338 {
 339         struct fuse_conn *fc = get_fuse_conn(inode);
 340         loff_t pos = page_offset(req->pages[0]);
 341         size_t count = req->num_pages << PAGE_CACHE_SHIFT;
 342         req->out.page_zeroing = 1;
 343         fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
 344         if (fc->async_read) {
 345                 req->end = fuse_readpages_end;
 346                 request_send_background(fc, req);
 347         } else {
 348                 request_send(fc, req);
 349                 fuse_readpages_end(fc, req);
 350         }
 351 }
 352
 353 struct fuse_readpages_data {
 354         struct fuse_req *req;
 355         struct file *file;
 356         struct inode *inode;
 357 };
 358
 359 static int fuse_readpages_fill(void *_data, struct page *page)
 360 {
 361         struct fuse_readpages_data *data = _data;
 362         struct fuse_req *req = data->req;
 363         struct inode *inode = data->inode;
 364         struct fuse_conn *fc = get_fuse_conn(inode);
 365
 366         if (req->num_pages &&
 367             (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 368              (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
 369              req->pages[req->num_pages - 1]->index + 1 != page->index)) {
 370                 fuse_send_readpages(req, data->file, inode);
 371                 data->req = req = fuse_get_req(fc);
 372                 if (IS_ERR(req)) {
 373                         unlock_page(page);
 374                         return PTR_ERR(req);
 375                 }
 376         }
 377         req->pages[req->num_pages] = page;
 378         req->num_pages ++;
 379         return 0;
 380 }
 381
 382 static int fuse_readpages(struct file *file, struct address_space *mapping,
 383                           struct list_head *pages, unsigned nr_pages)
 384 {
 385         struct inode *inode = mapping->host;
 386         struct fuse_conn *fc = get_fuse_conn(inode);
 387         struct fuse_readpages_data data;
 388         int err;
 389
 390         if (is_bad_inode(inode))
 391                 return -EIO;
 392
 393         data.file = file;
 394         data.inode = inode;
 395         data.req = fuse_get_req(fc);
 396         if (IS_ERR(data.req))
 397                 return PTR_ERR(data.req);
 398
 399         err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 400         if (!err) {
 401                 if (data.req->num_pages)
 402                         fuse_send_readpages(data.req, file, inode);
 403                 else
 404                         fuse_put_request(fc, data.req);
 405         }
 406         return err;
 407 }
 408
 409 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
 410                               struct inode *inode, loff_t pos, size_t count)
 411 {
 412         struct fuse_conn *fc = get_fuse_conn(inode);
 413         struct fuse_file *ff = file->private_data;
 414         struct fuse_write_in inarg;
 415         struct fuse_write_out outarg;
 416
 417         memset(&inarg, 0, sizeof(struct fuse_write_in));
 418         inarg.fh = ff->fh;
 419         inarg.offset = pos;
 420         inarg.size = count;
 421         req->in.h.opcode = FUSE_WRITE;
 422         req->in.h.nodeid = get_node_id(inode);
 423         req->inode = inode;
 424         req->file = file;
 425         req->in.argpages = 1;
 426         req->in.numargs = 2;
 427         req->in.args[0].size = sizeof(struct fuse_write_in);
 428         req->in.args[0].value = &inarg;
 429         req->in.args[1].size = count;
 430         req->out.numargs = 1;
 431         req->out.args[0].size = sizeof(struct fuse_write_out);
 432         req->out.args[0].value = &outarg;
 433         request_send(fc, req);
 434         return outarg.size;
 435 }
 436
 437 static int fuse_prepare_write(struct file *file, struct page *page,
 438                               unsigned offset, unsigned to)
 439 {
 440         /* No op */
 441         return 0;
 442 }
 443
 444 static int fuse_commit_write(struct file *file, struct page *page,
 445                              unsigned offset, unsigned to)
 446 {
 447         int err;
 448         size_t nres;
 449         unsigned count = to - offset;
 450         struct inode *inode = page->mapping->host;
 451         struct fuse_conn *fc = get_fuse_conn(inode);
 452         loff_t pos = page_offset(page) + offset;
 453         struct fuse_req *req;
 454
 455         if (is_bad_inode(inode))
 456                 return -EIO;
 457
 458         req = fuse_get_req(fc);
 459         if (IS_ERR(req))
 460                 return PTR_ERR(req);
 461
 462         req->num_pages = 1;
 463         req->pages[0] = page;
 464         req->page_offset = offset;
 465         nres = fuse_send_write(req, file, inode, pos, count);
 466         err = req->out.h.error;
 467         fuse_put_request(fc, req);
 468         if (!err && nres != count)
 469                 err = -EIO;
 470         if (!err) {
 471                 pos += count;
 472                 if (pos > i_size_read(inode))
 473                         i_size_write(inode, pos);
 474
 475                 if (offset == 0 && to == PAGE_CACHE_SIZE) {
 476                         clear_page_dirty(page);
 477                         SetPageUptodate(page);
 478                 }
 479         }
 480         fuse_invalidate_attr(inode);
 481         return err;
 482 }
 483
 484 static void fuse_release_user_pages(struct fuse_req *req, int write)
 485 {
 486         unsigned i;
 487
 488         for (i = 0; i < req->num_pages; i++) {
 489                 struct page *page = req->pages[i];
 490                 if (write)
 491                         set_page_dirty_lock(page);
 492                 put_page(page);
 493         }
 494 }
 495
 496 static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
 497                                unsigned nbytes, int write)
 498 {
 499         unsigned long user_addr = (unsigned long) buf;
 500         unsigned offset = user_addr & ~PAGE_MASK;
 501         int npages;
 502
 503         /* This doesn't work with nfsd */
 504         if (!current->mm)
 505                 return -EPERM;
 506
 507         nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
 508         npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
 509         npages = min(max(npages, 1), FUSE_MAX_PAGES_PER_REQ);
 510         down_read(&current->mm->mmap_sem);
 511         npages = get_user_pages(current, current->mm, user_addr, npages, write,
 512                                 0, req->pages, NULL);
 513         up_read(&current->mm->mmap_sem);
 514         if (npages < 0)
 515                 return npages;
 516
 517         req->num_pages = npages;
 518         req->page_offset = offset;
 519         return 0;
 520 }
 521
 522 static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
 523                               size_t count, loff_t *ppos, int write)
 524 {
 525         struct inode *inode = file->f_dentry->d_inode;
 526         struct fuse_conn *fc = get_fuse_conn(inode);
 527         size_t nmax = write ? fc->max_write : fc->max_read;
 528         loff_t pos = *ppos;
 529         ssize_t res = 0;
 530         struct fuse_req *req;
 531
 532         if (is_bad_inode(inode))
 533                 return -EIO;
 534
 535         req = fuse_get_req(fc);
 536         if (IS_ERR(req))
 537                 return PTR_ERR(req);
 538
 539         while (count) {
 540                 size_t nres;
 541                 size_t nbytes = min(count, nmax);
 542                 int err = fuse_get_user_pages(req, buf, nbytes, !write);
 543                 if (err) {
 544                         res = err;
 545                         break;
 546                 }
 547                 nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
 548                 nbytes = min(count, nbytes);
 549                 if (write)
 550                         nres = fuse_send_write(req, file, inode, pos, nbytes);
 551                 else
 552                         nres = fuse_send_read(req, file, inode, pos, nbytes);
 553                 fuse_release_user_pages(req, !write);
 554                 if (req->out.h.error) {
 555                         if (!res)
 556                                 res = req->out.h.error;
 557                         break;
 558                 } else if (nres > nbytes) {
 559                         res = -EIO;
 560                         break;
 561                 }
 562                 count -= nres;
 563                 res += nres;
 564                 pos += nres;
 565                 buf += nres;
 566                 if (nres != nbytes)
 567                         break;
 568                 if (count) {
 569                         fuse_put_request(fc, req);
 570                         req = fuse_get_req(fc);
 571                         if (IS_ERR(req))
 572                                 break;
 573                 }
 574         }
 575         fuse_put_request(fc, req);
 576         if (res > 0) {
 577                 if (write && pos > i_size_read(inode))
 578                         i_size_write(inode, pos);
 579                 *ppos = pos;
 580         }
 581         fuse_invalidate_attr(inode);
 582
 583         return res;
 584 }
 585
 586 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
 587                                      size_t count, loff_t *ppos)
 588 {
 589         return fuse_direct_io(file, buf, count, ppos, 0);
 590 }
 591
 592 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
 593                                  size_t count, loff_t *ppos)
 594 {
 595         struct inode *inode = file->f_dentry->d_inode;
 596         ssize_t res;
 597         /* Don't allow parallel writes to the same file */
 598         mutex_lock(&inode->i_mutex);
 599         res = fuse_direct_io(file, buf, count, ppos, 1);
 600         mutex_unlock(&inode->i_mutex);
 601         return res;
 602 }
 603
 604 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
 605 {
 606         if ((vma->vm_flags & VM_SHARED)) {
 607                 if ((vma->vm_flags & VM_WRITE))
 608                         return -ENODEV;
 609                 else
 610                         vma->vm_flags &= ~VM_MAYWRITE;
 611         }
 612         return generic_file_mmap(file, vma);
 613 }
 614
 615 static int fuse_set_page_dirty(struct page *page)
 616 {
 617         printk("fuse_set_page_dirty: should not happen\n");
 618         dump_stack();
 619         return 0;
 620 }
 621
 622 static const struct file_operations fuse_file_operations = {
 623         .llseek         = generic_file_llseek,
 624         .read           = generic_file_read,
 625         .write          = generic_file_write,
 626         .mmap           = fuse_file_mmap,
 627         .open           = fuse_open,
 628         .flush          = fuse_flush,
 629         .release        = fuse_release,
 630         .fsync          = fuse_fsync,
 631         .sendfile       = generic_file_sendfile,
 632 };
 633
 634 static const struct file_operations fuse_direct_io_file_operations = {
 635         .llseek         = generic_file_llseek,
 636         .read           = fuse_direct_read,
 637         .write          = fuse_direct_write,
 638         .open           = fuse_open,
 639         .flush          = fuse_flush,
 640         .release        = fuse_release,
 641         .fsync          = fuse_fsync,
 642         /* no mmap and sendfile */
 643 };
 644
 645 static struct address_space_operations fuse_file_aops  = {
 646         .readpage       = fuse_readpage,
 647         .prepare_write  = fuse_prepare_write,
 648         .commit_write   = fuse_commit_write,
 649         .readpages      = fuse_readpages,
 650         .set_page_dirty = fuse_set_page_dirty,
 651 };
 652
 653 void fuse_init_file_inode(struct inode *inode)
 654 {
 655         inode->i_fop = &fuse_file_operations;
 656         inode->i_data.a_ops = &fuse_file_aops;
 657 }