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