fs/fuse/file.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2005  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 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_request(fc);
  26         if (!req)
  27                 return -EINTR;
  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 void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff,
 117                        u64 nodeid, struct inode *inode, int flags, int isdir)
 118 {
 119         struct fuse_req * req = ff->release_req;
 120         struct fuse_release_in *inarg = &req->misc.release_in;
 121
 122         inarg->fh = ff->fh;
 123         inarg->flags = flags;
 124         req->in.h.opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
 125         req->in.h.nodeid = nodeid;
 126         req->inode = inode;
 127         req->in.numargs = 1;
 128         req->in.args[0].size = sizeof(struct fuse_release_in);
 129         req->in.args[0].value = inarg;
 130         request_send_background(fc, req);
 131         kfree(ff);
 132 }
 133
 134 int fuse_release_common(struct inode *inode, struct file *file, int isdir)
 135 {
 136         struct fuse_file *ff = file->private_data;
 137         if (ff) {
 138                 struct fuse_conn *fc = get_fuse_conn(inode);
 139                 u64 nodeid = get_node_id(inode);
 140                 fuse_send_release(fc, ff, nodeid, inode, file->f_flags, isdir);
 141         }
 142
 143         /* Return value is ignored by VFS */
 144         return 0;
 145 }
 146
 147 static int fuse_open(struct inode *inode, struct file *file)
 148 {
 149         return fuse_open_common(inode, file, 0);
 150 }
 151
 152 static int fuse_release(struct inode *inode, struct file *file)
 153 {
 154         return fuse_release_common(inode, file, 0);
 155 }
 156
 157 static int fuse_flush(struct file *file)
 158 {
 159         struct inode *inode = file->f_dentry->d_inode;
 160         struct fuse_conn *fc = get_fuse_conn(inode);
 161         struct fuse_file *ff = file->private_data;
 162         struct fuse_req *req;
 163         struct fuse_flush_in inarg;
 164         int err;
 165
 166         if (is_bad_inode(inode))
 167                 return -EIO;
 168
 169         if (fc->no_flush)
 170                 return 0;
 171
 172         req = fuse_get_request(fc);
 173         if (!req)
 174                 return -EINTR;
 175
 176         memset(&inarg, 0, sizeof(inarg));
 177         inarg.fh = ff->fh;
 178         req->in.h.opcode = FUSE_FLUSH;
 179         req->in.h.nodeid = get_node_id(inode);
 180         req->inode = inode;
 181         req->file = file;
 182         req->in.numargs = 1;
 183         req->in.args[0].size = sizeof(inarg);
 184         req->in.args[0].value = &inarg;
 185         request_send(fc, req);
 186         err = req->out.h.error;
 187         fuse_put_request(fc, req);
 188         if (err == -ENOSYS) {
 189                 fc->no_flush = 1;
 190                 err = 0;
 191         }
 192         return err;
 193 }
 194
 195 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
 196                       int isdir)
 197 {
 198         struct inode *inode = de->d_inode;
 199         struct fuse_conn *fc = get_fuse_conn(inode);
 200         struct fuse_file *ff = file->private_data;
 201         struct fuse_req *req;
 202         struct fuse_fsync_in inarg;
 203         int err;
 204
 205         if (is_bad_inode(inode))
 206                 return -EIO;
 207
 208         if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
 209                 return 0;
 210
 211         req = fuse_get_request(fc);
 212         if (!req)
 213                 return -EINTR;
 214
 215         memset(&inarg, 0, sizeof(inarg));
 216         inarg.fh = ff->fh;
 217         inarg.fsync_flags = datasync ? 1 : 0;
 218         req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
 219         req->in.h.nodeid = get_node_id(inode);
 220         req->inode = inode;
 221         req->file = file;
 222         req->in.numargs = 1;
 223         req->in.args[0].size = sizeof(inarg);
 224         req->in.args[0].value = &inarg;
 225         request_send(fc, req);
 226         err = req->out.h.error;
 227         fuse_put_request(fc, req);
 228         if (err == -ENOSYS) {
 229                 if (isdir)
 230                         fc->no_fsyncdir = 1;
 231                 else
 232                         fc->no_fsync = 1;
 233                 err = 0;
 234         }
 235         return err;
 236 }
 237
 238 static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
 239 {
 240         return fuse_fsync_common(file, de, datasync, 0);
 241 }
 242
 243 size_t fuse_send_read_common(struct fuse_req *req, struct file *file,
 244                              struct inode *inode, loff_t pos, size_t count,
 245                              int isdir)
 246 {
 247         struct fuse_conn *fc = get_fuse_conn(inode);
 248         struct fuse_file *ff = file->private_data;
 249         struct fuse_read_in inarg;
 250
 251         memset(&inarg, 0, sizeof(struct fuse_read_in));
 252         inarg.fh = ff->fh;
 253         inarg.offset = pos;
 254         inarg.size = count;
 255         req->in.h.opcode = isdir ? FUSE_READDIR : FUSE_READ;
 256         req->in.h.nodeid = get_node_id(inode);
 257         req->inode = inode;
 258         req->file = file;
 259         req->in.numargs = 1;
 260         req->in.args[0].size = sizeof(struct fuse_read_in);
 261         req->in.args[0].value = &inarg;
 262         req->out.argpages = 1;
 263         req->out.argvar = 1;
 264         req->out.numargs = 1;
 265         req->out.args[0].size = count;
 266         request_send(fc, req);
 267         return req->out.args[0].size;
 268 }
 269
 270 static inline size_t fuse_send_read(struct fuse_req *req, struct file *file,
 271                                     struct inode *inode, loff_t pos,
 272                                     size_t count)
 273 {
 274         return fuse_send_read_common(req, file, inode, pos, count, 0);
 275 }
 276
 277 static int fuse_readpage(struct file *file, struct page *page)
 278 {
 279         struct inode *inode = page->mapping->host;
 280         struct fuse_conn *fc = get_fuse_conn(inode);
 281         struct fuse_req *req;
 282         int err;
 283
 284         err = -EIO;
 285         if (is_bad_inode(inode))
 286                 goto out;
 287
 288         err = -EINTR;
 289         req = fuse_get_request(fc);
 290         if (!req)
 291                 goto out;
 292
 293         req->out.page_zeroing = 1;
 294         req->num_pages = 1;
 295         req->pages[0] = page;
 296         fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE);
 297         err = req->out.h.error;
 298         fuse_put_request(fc, req);
 299         if (!err)
 300                 SetPageUptodate(page);
 301         fuse_invalidate_attr(inode); /* atime changed */
 302  out:
 303         unlock_page(page);
 304         return err;
 305 }
 306
 307 static int fuse_send_readpages(struct fuse_req *req, struct file *file,
 308                                struct inode *inode)
 309 {
 310         loff_t pos = page_offset(req->pages[0]);
 311         size_t count = req->num_pages << PAGE_CACHE_SHIFT;
 312         unsigned i;
 313         req->out.page_zeroing = 1;
 314         fuse_send_read(req, file, inode, pos, count);
 315         for (i = 0; i < req->num_pages; i++) {
 316                 struct page *page = req->pages[i];
 317                 if (!req->out.h.error)
 318                         SetPageUptodate(page);
 319                 unlock_page(page);
 320         }
 321         return req->out.h.error;
 322 }
 323
 324 struct fuse_readpages_data {
 325         struct fuse_req *req;
 326         struct file *file;
 327         struct inode *inode;
 328 };
 329
 330 static int fuse_readpages_fill(void *_data, struct page *page)
 331 {
 332         struct fuse_readpages_data *data = _data;
 333         struct fuse_req *req = data->req;
 334         struct inode *inode = data->inode;
 335         struct fuse_conn *fc = get_fuse_conn(inode);
 336
 337         if (req->num_pages &&
 338             (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 339              (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
 340              req->pages[req->num_pages - 1]->index + 1 != page->index)) {
 341                 int err = fuse_send_readpages(req, data->file, inode);
 342                 if (err) {
 343                         unlock_page(page);
 344                         return err;
 345                 }
 346                 fuse_reset_request(req);
 347         }
 348         req->pages[req->num_pages] = page;
 349         req->num_pages ++;
 350         return 0;
 351 }
 352
 353 static int fuse_readpages(struct file *file, struct address_space *mapping,
 354                           struct list_head *pages, unsigned nr_pages)
 355 {
 356         struct inode *inode = mapping->host;
 357         struct fuse_conn *fc = get_fuse_conn(inode);
 358         struct fuse_readpages_data data;
 359         int err;
 360
 361         if (is_bad_inode(inode))
 362                 return -EIO;
 363
 364         data.file = file;
 365         data.inode = inode;
 366         data.req = fuse_get_request(fc);
 367         if (!data.req)
 368                 return -EINTR;
 369
 370         err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 371         if (!err && data.req->num_pages)
 372                 err = fuse_send_readpages(data.req, file, inode);
 373         fuse_put_request(fc, data.req);
 374         fuse_invalidate_attr(inode); /* atime changed */
 375         return err;
 376 }
 377
 378 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
 379                               struct inode *inode, loff_t pos, size_t count)
 380 {
 381         struct fuse_conn *fc = get_fuse_conn(inode);
 382         struct fuse_file *ff = file->private_data;
 383         struct fuse_write_in inarg;
 384         struct fuse_write_out outarg;
 385
 386         memset(&inarg, 0, sizeof(struct fuse_write_in));
 387         inarg.fh = ff->fh;
 388         inarg.offset = pos;
 389         inarg.size = count;
 390         req->in.h.opcode = FUSE_WRITE;
 391         req->in.h.nodeid = get_node_id(inode);
 392         req->inode = inode;
 393         req->file = file;
 394         req->in.argpages = 1;
 395         req->in.numargs = 2;
 396         req->in.args[0].size = sizeof(struct fuse_write_in);
 397         req->in.args[0].value = &inarg;
 398         req->in.args[1].size = count;
 399         req->out.numargs = 1;
 400         req->out.args[0].size = sizeof(struct fuse_write_out);
 401         req->out.args[0].value = &outarg;
 402         request_send(fc, req);
 403         return outarg.size;
 404 }
 405
 406 static int fuse_prepare_write(struct file *file, struct page *page,
 407                               unsigned offset, unsigned to)
 408 {
 409         /* No op */
 410         return 0;
 411 }
 412
 413 static int fuse_commit_write(struct file *file, struct page *page,
 414                              unsigned offset, unsigned to)
 415 {
 416         int err;
 417         size_t nres;
 418         unsigned count = to - offset;
 419         struct inode *inode = page->mapping->host;
 420         struct fuse_conn *fc = get_fuse_conn(inode);
 421         loff_t pos = page_offset(page) + offset;
 422         struct fuse_req *req;
 423
 424         if (is_bad_inode(inode))
 425                 return -EIO;
 426
 427         req = fuse_get_request(fc);
 428         if (!req)
 429                 return -EINTR;
 430
 431         req->num_pages = 1;
 432         req->pages[0] = page;
 433         req->page_offset = offset;
 434         nres = fuse_send_write(req, file, inode, pos, count);
 435         err = req->out.h.error;
 436         fuse_put_request(fc, req);
 437         if (!err && nres != count)
 438                 err = -EIO;
 439         if (!err) {
 440                 pos += count;
 441                 if (pos > i_size_read(inode))
 442                         i_size_write(inode, pos);
 443
 444                 if (offset == 0 && to == PAGE_CACHE_SIZE) {
 445                         clear_page_dirty(page);
 446                         SetPageUptodate(page);
 447                 }
 448         }
 449         fuse_invalidate_attr(inode);
 450         return err;
 451 }
 452
 453 static void fuse_release_user_pages(struct fuse_req *req, int write)
 454 {
 455         unsigned i;
 456
 457         for (i = 0; i < req->num_pages; i++) {
 458                 struct page *page = req->pages[i];
 459                 if (write)
 460                         set_page_dirty_lock(page);
 461                 put_page(page);
 462         }
 463 }
 464
 465 static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
 466                                unsigned nbytes, int write)
 467 {
 468         unsigned long user_addr = (unsigned long) buf;
 469         unsigned offset = user_addr & ~PAGE_MASK;
 470         int npages;
 471
 472         /* This doesn't work with nfsd */
 473         if (!current->mm)
 474                 return -EPERM;
 475
 476         nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
 477         npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
 478         npages = min(npages, FUSE_MAX_PAGES_PER_REQ);
 479         down_read(&current->mm->mmap_sem);
 480         npages = get_user_pages(current, current->mm, user_addr, npages, write,
 481                                 0, req->pages, NULL);
 482         up_read(&current->mm->mmap_sem);
 483         if (npages < 0)
 484                 return npages;
 485
 486         req->num_pages = npages;
 487         req->page_offset = offset;
 488         return 0;
 489 }
 490
 491 static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
 492                               size_t count, loff_t *ppos, int write)
 493 {
 494         struct inode *inode = file->f_dentry->d_inode;
 495         struct fuse_conn *fc = get_fuse_conn(inode);
 496         size_t nmax = write ? fc->max_write : fc->max_read;
 497         loff_t pos = *ppos;
 498         ssize_t res = 0;
 499         struct fuse_req *req;
 500
 501         if (is_bad_inode(inode))
 502                 return -EIO;
 503
 504         req = fuse_get_request(fc);
 505         if (!req)
 506                 return -EINTR;
 507
 508         while (count) {
 509                 size_t tmp;
 510                 size_t nres;
 511                 size_t nbytes = min(count, nmax);
 512                 int err = fuse_get_user_pages(req, buf, nbytes, !write);
 513                 if (err) {
 514                         res = err;
 515                         break;
 516                 }
 517                 tmp = (req->num_pages << PAGE_SHIFT) - req->page_offset;
 518                 nbytes = min(nbytes, tmp);
 519                 if (write)
 520                         nres = fuse_send_write(req, file, inode, pos, nbytes);
 521                 else
 522                         nres = fuse_send_read(req, file, inode, pos, nbytes);
 523                 fuse_release_user_pages(req, !write);
 524                 if (req->out.h.error) {
 525                         if (!res)
 526                                 res = req->out.h.error;
 527                         break;
 528                 } else if (nres > nbytes) {
 529                         res = -EIO;
 530                         break;
 531                 }
 532                 count -= nres;
 533                 res += nres;
 534                 pos += nres;
 535                 buf += nres;
 536                 if (nres != nbytes)
 537                         break;
 538                 if (count)
 539                         fuse_reset_request(req);
 540         }
 541         fuse_put_request(fc, req);
 542         if (res > 0) {
 543                 if (write && pos > i_size_read(inode))
 544                         i_size_write(inode, pos);
 545                 *ppos = pos;
 546         }
 547         fuse_invalidate_attr(inode);
 548
 549         return res;
 550 }
 551
 552 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
 553                                      size_t count, loff_t *ppos)
 554 {
 555         return fuse_direct_io(file, buf, count, ppos, 0);
 556 }
 557
 558 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
 559                                  size_t count, loff_t *ppos)
 560 {
 561         struct inode *inode = file->f_dentry->d_inode;
 562         ssize_t res;
 563         /* Don't allow parallel writes to the same file */
 564         down(&inode->i_sem);
 565         res = fuse_direct_io(file, buf, count, ppos, 1);
 566         up(&inode->i_sem);
 567         return res;
 568 }
 569
 570 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
 571 {
 572         if ((vma->vm_flags & VM_SHARED)) {
 573                 if ((vma->vm_flags & VM_WRITE))
 574                         return -ENODEV;
 575                 else
 576                         vma->vm_flags &= ~VM_MAYWRITE;
 577         }
 578         return generic_file_mmap(file, vma);
 579 }
 580
 581 static int fuse_set_page_dirty(struct page *page)
 582 {
 583         printk("fuse_set_page_dirty: should not happen\n");
 584         dump_stack();
 585         return 0;
 586 }
 587
 588 static struct file_operations fuse_file_operations = {
 589         .llseek         = generic_file_llseek,
 590         .read           = generic_file_read,
 591         .write          = generic_file_write,
 592         .mmap           = fuse_file_mmap,
 593         .open           = fuse_open,
 594         .flush          = fuse_flush,
 595         .release        = fuse_release,
 596         .fsync          = fuse_fsync,
 597         .sendfile       = generic_file_sendfile,
 598 };
 599
 600 static struct file_operations fuse_direct_io_file_operations = {
 601         .llseek         = generic_file_llseek,
 602         .read           = fuse_direct_read,
 603         .write          = fuse_direct_write,
 604         .open           = fuse_open,
 605         .flush          = fuse_flush,
 606         .release        = fuse_release,
 607         .fsync          = fuse_fsync,
 608         /* no mmap and sendfile */
 609 };
 610
 611 static struct address_space_operations fuse_file_aops  = {
 612         .readpage       = fuse_readpage,
 613         .prepare_write  = fuse_prepare_write,
 614         .commit_write   = fuse_commit_write,
 615         .readpages      = fuse_readpages,
 616         .set_page_dirty = fuse_set_page_dirty,
 617 };
 618
 619 void fuse_init_file_inode(struct inode *inode)
 620 {
 621         inode->i_fop = &fuse_file_operations;
 622         inode->i_data.a_ops = &fuse_file_aops;
 623 }