fs/ecryptfs/mmap.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  * This is where eCryptfs coordinates the symmetric encryption and
   4  * decryption of the file data as it passes between the lower
   5  * encrypted file and the upper decrypted file.
   6  *
   7  * Copyright (C) 1997-2003 Erez Zadok
   8  * Copyright (C) 2001-2003 Stony Brook University
   9  * Copyright (C) 2004-2007 International Business Machines Corp.
  10  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  25  * 02111-1307, USA.
  26  */
  27
  28 #include <linux/pagemap.h>
  29 #include <linux/writeback.h>
  30 #include <linux/page-flags.h>
  31 #include <linux/mount.h>
  32 #include <linux/file.h>
  33 #include <linux/crypto.h>
  34 #include <linux/scatterlist.h>
  35 #include "ecryptfs_kernel.h"
  36
  37 struct kmem_cache *ecryptfs_lower_page_cache;
  38
  39 /**
  40  * ecryptfs_get1page
  41  *
  42  * Get one page from cache or lower f/s, return error otherwise.
  43  *
  44  * Returns unlocked and up-to-date page (if ok), with increased
  45  * refcnt.
  46  */
  47 static struct page *ecryptfs_get1page(struct file *file, int index)
  48 {
  49         struct page *page;
  50         struct dentry *dentry;
  51         struct inode *inode;
  52         struct address_space *mapping;
  53
  54         dentry = file->f_path.dentry;
  55         inode = dentry->d_inode;
  56         mapping = inode->i_mapping;
  57         page = read_cache_page(mapping, index,
  58                                (filler_t *)mapping->a_ops->readpage,
  59                                (void *)file);
  60         if (IS_ERR(page))
  61                 goto out;
  62         wait_on_page_locked(page);
  63 out:
  64         return page;
  65 }
  66
  67 static
  68 int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros);
  69
  70 /**
  71  * ecryptfs_fill_zeros
  72  * @file: The ecryptfs file
  73  * @new_length: The new length of the data in the underlying file;
  74  *              everything between the prior end of the file and the
  75  *              new end of the file will be filled with zero's.
  76  *              new_length must be greater than  current length
  77  *
  78  * Function for handling lseek-ing past the end of the file.
  79  *
  80  * This function does not support shrinking, only growing a file.
  81  *
  82  * Returns zero on success; non-zero otherwise.
  83  */
  84 int ecryptfs_fill_zeros(struct file *file, loff_t new_length)
  85 {
  86         int rc = 0;
  87         struct dentry *dentry = file->f_path.dentry;
  88         struct inode *inode = dentry->d_inode;
  89         pgoff_t old_end_page_index = 0;
  90         pgoff_t index = old_end_page_index;
  91         int old_end_pos_in_page = -1;
  92         pgoff_t new_end_page_index;
  93         int new_end_pos_in_page;
  94         loff_t cur_length = i_size_read(inode);
  95
  96         if (cur_length != 0) {
  97                 index = old_end_page_index =
  98                     ((cur_length - 1) >> PAGE_CACHE_SHIFT);
  99                 old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK);
 100         }
 101         new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
 102         new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
 103         ecryptfs_printk(KERN_DEBUG, "old_end_page_index = [0x%.16x]; "
 104                         "old_end_pos_in_page = [%d]; "
 105                         "new_end_page_index = [0x%.16x]; "
 106                         "new_end_pos_in_page = [%d]\n",
 107                         old_end_page_index, old_end_pos_in_page,
 108                         new_end_page_index, new_end_pos_in_page);
 109         if (old_end_page_index == new_end_page_index) {
 110                 /* Start and end are in the same page; we just need to
 111                  * set a portion of the existing page to zero's */
 112                 rc = write_zeros(file, index, (old_end_pos_in_page + 1),
 113                                  (new_end_pos_in_page - old_end_pos_in_page));
 114                 if (rc)
 115                         ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
 116                                         "index=[0x%.16x], "
 117                                         "old_end_pos_in_page=[d], "
 118                                         "(PAGE_CACHE_SIZE - new_end_pos_in_page"
 119                                         "=[%d]"
 120                                         ")=[d]) returned [%d]\n", file, index,
 121                                         old_end_pos_in_page,
 122                                         new_end_pos_in_page,
 123                                         (PAGE_CACHE_SIZE - new_end_pos_in_page),
 124                                         rc);
 125                 goto out;
 126         }
 127         /* Fill the remainder of the previous last page with zeros */
 128         rc = write_zeros(file, index, (old_end_pos_in_page + 1),
 129                          ((PAGE_CACHE_SIZE - 1) - old_end_pos_in_page));
 130         if (rc) {
 131                 ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
 132                                 "index=[0x%.16x], old_end_pos_in_page=[d], "
 133                                 "(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) "
 134                                 "returned [%d]\n", file, index,
 135                                 old_end_pos_in_page,
 136                                 (PAGE_CACHE_SIZE - old_end_pos_in_page), rc);
 137                 goto out;
 138         }
 139         index++;
 140         while (index < new_end_page_index) {
 141                 /* Fill all intermediate pages with zeros */
 142                 rc = write_zeros(file, index, 0, PAGE_CACHE_SIZE);
 143                 if (rc) {
 144                         ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
 145                                         "index=[0x%.16x], "
 146                                         "old_end_pos_in_page=[d], "
 147                                         "(PAGE_CACHE_SIZE - new_end_pos_in_page"
 148                                         "=[%d]"
 149                                         ")=[d]) returned [%d]\n", file, index,
 150                                         old_end_pos_in_page,
 151                                         new_end_pos_in_page,
 152                                         (PAGE_CACHE_SIZE - new_end_pos_in_page),
 153                                         rc);
 154                         goto out;
 155                 }
 156                 index++;
 157         }
 158         /* Fill the portion at the beginning of the last new page with
 159          * zero's */
 160         rc = write_zeros(file, index, 0, (new_end_pos_in_page + 1));
 161         if (rc) {
 162                 ecryptfs_printk(KERN_ERR, "write_zeros(file="
 163                                 "[%p], index=[0x%.16x], 0, "
 164                                 "new_end_pos_in_page=[%d]"
 165                                 "returned [%d]\n", file, index,
 166                                 new_end_pos_in_page, rc);
 167                 goto out;
 168         }
 169 out:
 170         return rc;
 171 }
 172
 173 /**
 174  * ecryptfs_writepage
 175  * @page: Page that is locked before this call is made
 176  *
 177  * Returns zero on success; non-zero otherwise
 178  */
 179 static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
 180 {
 181         struct ecryptfs_page_crypt_context ctx;
 182         int rc;
 183
 184         ctx.page = page;
 185         ctx.mode = ECRYPTFS_WRITEPAGE_MODE;
 186         ctx.param.wbc = wbc;
 187         rc = ecryptfs_encrypt_page(&ctx);
 188         if (rc) {
 189                 ecryptfs_printk(KERN_WARNING, "Error encrypting "
 190                                 "page (upper index [0x%.16x])\n", page->index);
 191                 ClearPageUptodate(page);
 192                 goto out;
 193         }
 194         SetPageUptodate(page);
 195         unlock_page(page);
 196 out:
 197         return rc;
 198 }
 199
 200 /**
 201  * Reads the data from the lower file file at index lower_page_index
 202  * and copies that data into page.
 203  *
 204  * @param page  Page to fill
 205  * @param lower_page_index Index of the page in the lower file to get
 206  */
 207 int ecryptfs_do_readpage(struct file *file, struct page *page,
 208                          pgoff_t lower_page_index)
 209 {
 210         int rc;
 211         struct dentry *dentry;
 212         struct file *lower_file;
 213         struct dentry *lower_dentry;
 214         struct inode *inode;
 215         struct inode *lower_inode;
 216         char *page_data;
 217         struct page *lower_page = NULL;
 218         char *lower_page_data;
 219         const struct address_space_operations *lower_a_ops;
 220
 221         dentry = file->f_path.dentry;
 222         lower_file = ecryptfs_file_to_lower(file);
 223         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 224         inode = dentry->d_inode;
 225         lower_inode = ecryptfs_inode_to_lower(inode);
 226         lower_a_ops = lower_inode->i_mapping->a_ops;
 227         lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index,
 228                                      (filler_t *)lower_a_ops->readpage,
 229                                      (void *)lower_file);
 230         if (IS_ERR(lower_page)) {
 231                 rc = PTR_ERR(lower_page);
 232                 lower_page = NULL;
 233                 ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
 234                 goto out;
 235         }
 236         wait_on_page_locked(lower_page);
 237         page_data = (char *)kmap(page);
 238         if (!page_data) {
 239                 rc = -ENOMEM;
 240                 ecryptfs_printk(KERN_ERR, "Error mapping page\n");
 241                 goto out;
 242         }
 243         lower_page_data = (char *)kmap(lower_page);
 244         if (!lower_page_data) {
 245                 rc = -ENOMEM;
 246                 ecryptfs_printk(KERN_ERR, "Error mapping page\n");
 247                 kunmap(page);
 248                 goto out;
 249         }
 250         memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
 251         kunmap(lower_page);
 252         kunmap(page);
 253         rc = 0;
 254 out:
 255         if (likely(lower_page))
 256                 page_cache_release(lower_page);
 257         if (rc == 0)
 258                 SetPageUptodate(page);
 259         else
 260                 ClearPageUptodate(page);
 261         return rc;
 262 }
 263
 264 /**
 265  * ecryptfs_readpage
 266  * @file: This is an ecryptfs file
 267  * @page: ecryptfs associated page to stick the read data into
 268  *
 269  * Read in a page, decrypting if necessary.
 270  *
 271  * Returns zero on success; non-zero on error.
 272  */
 273 static int ecryptfs_readpage(struct file *file, struct page *page)
 274 {
 275         int rc = 0;
 276         struct ecryptfs_crypt_stat *crypt_stat;
 277
 278         BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode));
 279         crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
 280                         ->crypt_stat;
 281         if (!crypt_stat
 282             || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)
 283             || ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) {
 284                 ecryptfs_printk(KERN_DEBUG,
 285                                 "Passing through unencrypted page\n");
 286                 rc = ecryptfs_do_readpage(file, page, page->index);
 287                 if (rc) {
 288                         ecryptfs_printk(KERN_ERR, "Error reading page; rc = "
 289                                         "[%d]\n", rc);
 290                         goto out;
 291                 }
 292         } else {
 293                 rc = ecryptfs_decrypt_page(file, page);
 294                 if (rc) {
 295
 296                         ecryptfs_printk(KERN_ERR, "Error decrypting page; "
 297                                         "rc = [%d]\n", rc);
 298                         goto out;
 299                 }
 300         }
 301         SetPageUptodate(page);
 302 out:
 303         if (rc)
 304                 ClearPageUptodate(page);
 305         ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
 306                         page->index);
 307         unlock_page(page);
 308         return rc;
 309 }
 310
 311 /**
 312  * Called with lower inode mutex held.
 313  */
 314 static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
 315 {
 316         struct inode *inode = page->mapping->host;
 317         int end_byte_in_page;
 318         int rc = 0;
 319         char *page_virt;
 320
 321         if ((i_size_read(inode) / PAGE_CACHE_SIZE) == page->index) {
 322                 end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
 323                 if (to > end_byte_in_page)
 324                         end_byte_in_page = to;
 325                 page_virt = kmap(page);
 326                 if (!page_virt) {
 327                         rc = -ENOMEM;
 328                         ecryptfs_printk(KERN_WARNING,
 329                                         "Could not map page\n");
 330                         goto out;
 331                 }
 332                 memset((page_virt + end_byte_in_page), 0,
 333                        (PAGE_CACHE_SIZE - end_byte_in_page));
 334                 kunmap(page);
 335         }
 336 out:
 337         return rc;
 338 }
 339
 340 static int ecryptfs_prepare_write(struct file *file, struct page *page,
 341                                   unsigned from, unsigned to)
 342 {
 343         int rc = 0;
 344
 345         kmap(page);
 346         if (from == 0 && to == PAGE_CACHE_SIZE)
 347                 goto out;       /* If we are writing a full page, it will be
 348                                    up to date. */
 349         if (!PageUptodate(page))
 350                 rc = ecryptfs_do_readpage(file, page, page->index);
 351 out:
 352         return rc;
 353 }
 354
 355 int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
 356                                      char **lower_virt,
 357                                      struct inode *lower_inode,
 358                                      unsigned long lower_page_index)
 359 {
 360         int rc = 0;
 361
 362         (*lower_page) = grab_cache_page(lower_inode->i_mapping,
 363                                         lower_page_index);
 364         if (!(*lower_page)) {
 365                 ecryptfs_printk(KERN_ERR, "grab_cache_page for "
 366                                 "lower_page_index = [0x%.16x] failed\n",
 367                                 lower_page_index);
 368                 rc = -EINVAL;
 369                 goto out;
 370         }
 371         if (lower_virt)
 372                 (*lower_virt) = kmap((*lower_page));
 373         else
 374                 kmap((*lower_page));
 375 out:
 376         return rc;
 377 }
 378
 379 int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
 380                                               struct inode *lower_inode,
 381                                               struct writeback_control *wbc)
 382 {
 383         int rc = 0;
 384
 385         rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc);
 386         if (rc) {
 387                 ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); "
 388                                 "rc = [%d]\n", rc);
 389                 goto out;
 390         }
 391         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
 392         page_cache_release(lower_page);
 393 out:
 394         return rc;
 395 }
 396
 397 static void ecryptfs_unmap_and_release_lower_page(struct page *lower_page)
 398 {
 399         kunmap(lower_page);
 400         ecryptfs_printk(KERN_DEBUG, "Unlocking lower page with index = "
 401                         "[0x%.16x]\n", lower_page->index);
 402         unlock_page(lower_page);
 403         page_cache_release(lower_page);
 404 }
 405
 406 /**
 407  * ecryptfs_write_inode_size_to_header
 408  *
 409  * Writes the lower file size to the first 8 bytes of the header.
 410  *
 411  * Returns zero on success; non-zero on error.
 412  */
 413 static int ecryptfs_write_inode_size_to_header(struct file *lower_file,
 414                                                struct inode *lower_inode,
 415                                                struct inode *inode)
 416 {
 417         int rc = 0;
 418         struct page *header_page;
 419         char *header_virt;
 420         const struct address_space_operations *lower_a_ops;
 421         u64 file_size;
 422
 423         rc = ecryptfs_grab_and_map_lower_page(&header_page, &header_virt,
 424                                               lower_inode, 0);
 425         if (rc) {
 426                 ecryptfs_printk(KERN_ERR, "grab_cache_page for header page "
 427                                 "failed\n");
 428                 goto out;
 429         }
 430         lower_a_ops = lower_inode->i_mapping->a_ops;
 431         rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8);
 432         file_size = (u64)i_size_read(inode);
 433         ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size);
 434         file_size = cpu_to_be64(file_size);
 435         memcpy(header_virt, &file_size, sizeof(u64));
 436         rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8);
 437         if (rc < 0)
 438                 ecryptfs_printk(KERN_ERR, "Error commiting header page "
 439                                 "write\n");
 440         ecryptfs_unmap_and_release_lower_page(header_page);
 441         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
 442         mark_inode_dirty_sync(inode);
 443 out:
 444         return rc;
 445 }
 446
 447 static int ecryptfs_write_inode_size_to_xattr(struct inode *lower_inode,
 448                                               struct inode *inode,
 449                                               struct dentry *ecryptfs_dentry,
 450                                               int lower_i_mutex_held)
 451 {
 452         ssize_t size;
 453         void *xattr_virt;
 454         struct dentry *lower_dentry;
 455         u64 file_size;
 456         int rc;
 457
 458         xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
 459         if (!xattr_virt) {
 460                 printk(KERN_ERR "Out of memory whilst attempting to write "
 461                        "inode size to xattr\n");
 462                 rc = -ENOMEM;
 463                 goto out;
 464         }
 465         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 466         if (!lower_dentry->d_inode->i_op->getxattr) {
 467                 printk(KERN_WARNING
 468                        "No support for setting xattr in lower filesystem\n");
 469                 rc = -ENOSYS;
 470                 kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
 471                 goto out;
 472         }
 473         if (!lower_i_mutex_held)
 474                 mutex_lock(&lower_dentry->d_inode->i_mutex);
 475         size = lower_dentry->d_inode->i_op->getxattr(lower_dentry,
 476                                                      ECRYPTFS_XATTR_NAME,
 477                                                      xattr_virt,
 478                                                      PAGE_CACHE_SIZE);
 479         if (!lower_i_mutex_held)
 480                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
 481         if (size < 0)
 482                 size = 8;
 483         file_size = (u64)i_size_read(inode);
 484         file_size = cpu_to_be64(file_size);
 485         memcpy(xattr_virt, &file_size, sizeof(u64));
 486         if (!lower_i_mutex_held)
 487                 mutex_lock(&lower_dentry->d_inode->i_mutex);
 488         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry,
 489                                                    ECRYPTFS_XATTR_NAME,
 490                                                    xattr_virt, size, 0);
 491         if (!lower_i_mutex_held)
 492                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
 493         if (rc)
 494                 printk(KERN_ERR "Error whilst attempting to write inode size "
 495                        "to lower file xattr; rc = [%d]\n", rc);
 496         kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
 497 out:
 498         return rc;
 499 }
 500
 501 int
 502 ecryptfs_write_inode_size_to_metadata(struct file *lower_file,
 503                                       struct inode *lower_inode,
 504                                       struct inode *inode,
 505                                       struct dentry *ecryptfs_dentry,
 506                                       int lower_i_mutex_held)
 507 {
 508         struct ecryptfs_crypt_stat *crypt_stat;
 509
 510         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 511         if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 512                 return ecryptfs_write_inode_size_to_xattr(lower_inode, inode,
 513                                                           ecryptfs_dentry,
 514                                                           lower_i_mutex_held);
 515         else
 516                 return ecryptfs_write_inode_size_to_header(lower_file,
 517                                                            lower_inode,
 518                                                            inode);
 519 }
 520
 521 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
 522                             struct file *lower_file,
 523                             unsigned long lower_page_index, int byte_offset,
 524                             int region_bytes)
 525 {
 526         int rc = 0;
 527
 528         rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL, lower_inode,
 529                                               lower_page_index);
 530         if (rc) {
 531                 ecryptfs_printk(KERN_ERR, "Error attempting to grab and map "
 532                                 "lower page with index [0x%.16x]\n",
 533                                 lower_page_index);
 534                 goto out;
 535         }
 536         rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file,
 537                                                           (*lower_page),
 538                                                           byte_offset,
 539                                                           region_bytes);
 540         if (rc) {
 541                 ecryptfs_printk(KERN_ERR, "prepare_write for "
 542                                 "lower_page_index = [0x%.16x] failed; rc = "
 543                                 "[%d]\n", lower_page_index, rc);
 544         }
 545 out:
 546         if (rc && (*lower_page)) {
 547                 ecryptfs_unmap_and_release_lower_page(*lower_page);
 548                 (*lower_page) = NULL;
 549         }
 550         return rc;
 551 }
 552
 553 /**
 554  * ecryptfs_commit_lower_page
 555  *
 556  * Returns zero on success; non-zero on error
 557  */
 558 int
 559 ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
 560                            struct file *lower_file, int byte_offset,
 561                            int region_size)
 562 {
 563         int rc = 0;
 564
 565         rc = lower_inode->i_mapping->a_ops->commit_write(
 566                 lower_file, lower_page, byte_offset, region_size);
 567         if (rc < 0) {
 568                 ecryptfs_printk(KERN_ERR,
 569                                 "Error committing write; rc = [%d]\n", rc);
 570         } else
 571                 rc = 0;
 572         ecryptfs_unmap_and_release_lower_page(lower_page);
 573         return rc;
 574 }
 575
 576 /**
 577  * ecryptfs_copy_page_to_lower
 578  *
 579  * Used for plaintext pass-through; no page index interpolation
 580  * required.
 581  */
 582 int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
 583                                 struct file *lower_file)
 584 {
 585         int rc = 0;
 586         struct page *lower_page;
 587
 588         rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file,
 589                                      page->index, 0, PAGE_CACHE_SIZE);
 590         if (rc) {
 591                 ecryptfs_printk(KERN_ERR, "Error attempting to get page "
 592                                 "at index [0x%.16x]\n", page->index);
 593                 goto out;
 594         }
 595         /* TODO: aops */
 596         memcpy((char *)page_address(lower_page), page_address(page),
 597                PAGE_CACHE_SIZE);
 598         rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file,
 599                                         0, PAGE_CACHE_SIZE);
 600         if (rc)
 601                 ecryptfs_printk(KERN_ERR, "Error attempting to commit page "
 602                                 "at index [0x%.16x]\n", page->index);
 603 out:
 604         return rc;
 605 }
 606
 607 struct kmem_cache *ecryptfs_xattr_cache;
 608
 609 /**
 610  * ecryptfs_commit_write
 611  * @file: The eCryptfs file object
 612  * @page: The eCryptfs page
 613  * @from: Ignored (we rotate the page IV on each write)
 614  * @to: Ignored
 615  *
 616  * This is where we encrypt the data and pass the encrypted data to
 617  * the lower filesystem.  In OpenPGP-compatible mode, we operate on
 618  * entire underlying packets.
 619  */
 620 static int ecryptfs_commit_write(struct file *file, struct page *page,
 621                                  unsigned from, unsigned to)
 622 {
 623         struct ecryptfs_page_crypt_context ctx;
 624         loff_t pos;
 625         struct inode *inode;
 626         struct inode *lower_inode;
 627         struct file *lower_file;
 628         struct ecryptfs_crypt_stat *crypt_stat;
 629         int rc;
 630
 631         inode = page->mapping->host;
 632         lower_inode = ecryptfs_inode_to_lower(inode);
 633         lower_file = ecryptfs_file_to_lower(file);
 634         mutex_lock(&lower_inode->i_mutex);
 635         crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
 636                                 ->crypt_stat;
 637         if (ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) {
 638                 ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
 639                         "crypt_stat at memory location [%p]\n", crypt_stat);
 640                 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
 641         } else
 642                 ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
 643         ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
 644                         "(page w/ index = [0x%.16x], to = [%d])\n", page->index,
 645                         to);
 646         rc = fill_zeros_to_end_of_page(page, to);
 647         if (rc) {
 648                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
 649                                 "zeros in page with index = [0x%.16x]\n",
 650                                 page->index);
 651                 goto out;
 652         }
 653         ctx.page = page;
 654         ctx.mode = ECRYPTFS_PREPARE_COMMIT_MODE;
 655         ctx.param.lower_file = lower_file;
 656         rc = ecryptfs_encrypt_page(&ctx);
 657         if (rc) {
 658                 ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
 659                                 "index [0x%.16x])\n", page->index);
 660                 goto out;
 661         }
 662         inode->i_blocks = lower_inode->i_blocks;
 663         pos = (page->index << PAGE_CACHE_SHIFT) + to;
 664         if (pos > i_size_read(inode)) {
 665                 i_size_write(inode, pos);
 666                 ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
 667                                 "[0x%.16x]\n", i_size_read(inode));
 668         }
 669         rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode,
 670                                                    inode, file->f_dentry,
 671                                                    ECRYPTFS_LOWER_I_MUTEX_HELD);
 672         if (rc)
 673                 printk(KERN_ERR "Error writing inode size to metadata; "
 674                        "rc = [%d]\n", rc);
 675         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
 676         mark_inode_dirty_sync(inode);
 677 out:
 678         kunmap(page); /* mapped in prior call (prepare_write) */
 679         if (rc < 0)
 680                 ClearPageUptodate(page);
 681         else
 682                 SetPageUptodate(page);
 683         mutex_unlock(&lower_inode->i_mutex);
 684         return rc;
 685 }
 686
 687 /**
 688  * write_zeros
 689  * @file: The ecryptfs file
 690  * @index: The index in which we are writing
 691  * @start: The position after the last block of data
 692  * @num_zeros: The number of zeros to write
 693  *
 694  * Write a specified number of zero's to a page.
 695  *
 696  * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE
 697  */
 698 static
 699 int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
 700 {
 701         int rc = 0;
 702         struct page *tmp_page;
 703
 704         tmp_page = ecryptfs_get1page(file, index);
 705         if (IS_ERR(tmp_page)) {
 706                 ecryptfs_printk(KERN_ERR, "Error getting page at index "
 707                                 "[0x%.16x]\n", index);
 708                 rc = PTR_ERR(tmp_page);
 709                 goto out;
 710         }
 711         kmap(tmp_page);
 712         rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros);
 713         if (rc) {
 714                 ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
 715                                 "to remainder of page at index [0x%.16x]\n",
 716                                 index);
 717                 kunmap(tmp_page);
 718                 page_cache_release(tmp_page);
 719                 goto out;
 720         }
 721         memset(((char *)page_address(tmp_page) + start), 0, num_zeros);
 722         rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
 723         if (rc < 0) {
 724                 ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
 725                                 "to remainder of page at index [0x%.16x]\n",
 726                                 index);
 727                 kunmap(tmp_page);
 728                 page_cache_release(tmp_page);
 729                 goto out;
 730         }
 731         rc = 0;
 732         kunmap(tmp_page);
 733         page_cache_release(tmp_page);
 734 out:
 735         return rc;
 736 }
 737
 738 static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
 739 {
 740         int rc = 0;
 741         struct inode *inode;
 742         struct inode *lower_inode;
 743
 744         inode = (struct inode *)mapping->host;
 745         lower_inode = ecryptfs_inode_to_lower(inode);
 746         if (lower_inode->i_mapping->a_ops->bmap)
 747                 rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping,
 748                                                          block);
 749         return rc;
 750 }
 751
 752 static void ecryptfs_sync_page(struct page *page)
 753 {
 754         struct inode *inode;
 755         struct inode *lower_inode;
 756         struct page *lower_page;
 757
 758         inode = page->mapping->host;
 759         lower_inode = ecryptfs_inode_to_lower(inode);
 760         /* NOTE: Recently swapped with grab_cache_page(), since
 761          * sync_page() just makes sure that pending I/O gets done. */
 762         lower_page = find_lock_page(lower_inode->i_mapping, page->index);
 763         if (!lower_page) {
 764                 ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n");
 765                 return;
 766         }
 767         lower_page->mapping->a_ops->sync_page(lower_page);
 768         ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
 769                         lower_page->index);
 770         unlock_page(lower_page);
 771         page_cache_release(lower_page);
 772 }
 773
 774 struct address_space_operations ecryptfs_aops = {
 775         .writepage = ecryptfs_writepage,
 776         .readpage = ecryptfs_readpage,
 777         .prepare_write = ecryptfs_prepare_write,
 778         .commit_write = ecryptfs_commit_write,
 779         .bmap = ecryptfs_bmap,
 780         .sync_page = ecryptfs_sync_page,
 781 };