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