file.c 7.3 KB

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  1. /*
  2. * file.c
  3. *
  4. * PURPOSE
  5. * File handling routines for the OSTA-UDF(tm) filesystem.
  6. *
  7. * COPYRIGHT
  8. * This file is distributed under the terms of the GNU General Public
  9. * License (GPL). Copies of the GPL can be obtained from:
  10. * ftp://prep.ai.mit.edu/pub/gnu/GPL
  11. * Each contributing author retains all rights to their own work.
  12. *
  13. * (C) 1998-1999 Dave Boynton
  14. * (C) 1998-2004 Ben Fennema
  15. * (C) 1999-2000 Stelias Computing Inc
  16. *
  17. * HISTORY
  18. *
  19. * 10/02/98 dgb Attempt to integrate into udf.o
  20. * 10/07/98 Switched to using generic_readpage, etc., like isofs
  21. * And it works!
  22. * 12/06/98 blf Added udf_file_read. uses generic_file_read for all cases but
  23. * ICBTAG_FLAG_AD_IN_ICB.
  24. * 04/06/99 64 bit file handling on 32 bit systems taken from ext2 file.c
  25. * 05/12/99 Preliminary file write support
  26. */
  27. #include "udfdecl.h"
  28. #include <linux/fs.h>
  29. #include <linux/uaccess.h>
  30. #include <linux/kernel.h>
  31. #include <linux/string.h> /* memset */
  32. #include <linux/capability.h>
  33. #include <linux/errno.h>
  34. #include <linux/pagemap.h>
  35. #include <linux/uio.h>
  36. #include "udf_i.h"
  37. #include "udf_sb.h"
  38. static void __udf_adinicb_readpage(struct page *page)
  39. {
  40. struct inode *inode = page->mapping->host;
  41. char *kaddr;
  42. struct udf_inode_info *iinfo = UDF_I(inode);
  43. loff_t isize = i_size_read(inode);
  44. /*
  45. * We have to be careful here as truncate can change i_size under us.
  46. * So just sample it once and use the same value everywhere.
  47. */
  48. kaddr = kmap_atomic(page);
  49. memcpy(kaddr, iinfo->i_data + iinfo->i_lenEAttr, isize);
  50. memset(kaddr + isize, 0, PAGE_SIZE - isize);
  51. flush_dcache_page(page);
  52. SetPageUptodate(page);
  53. kunmap_atomic(kaddr);
  54. }
  55. static int udf_adinicb_readpage(struct file *file, struct page *page)
  56. {
  57. BUG_ON(!PageLocked(page));
  58. __udf_adinicb_readpage(page);
  59. unlock_page(page);
  60. return 0;
  61. }
  62. static int udf_adinicb_writepage(struct page *page,
  63. struct writeback_control *wbc)
  64. {
  65. struct inode *inode = page->mapping->host;
  66. char *kaddr;
  67. struct udf_inode_info *iinfo = UDF_I(inode);
  68. BUG_ON(!PageLocked(page));
  69. kaddr = kmap_atomic(page);
  70. memcpy(iinfo->i_data + iinfo->i_lenEAttr, kaddr, i_size_read(inode));
  71. SetPageUptodate(page);
  72. kunmap_atomic(kaddr);
  73. mark_inode_dirty(inode);
  74. unlock_page(page);
  75. return 0;
  76. }
  77. static int udf_adinicb_write_begin(struct file *file,
  78. struct address_space *mapping, loff_t pos,
  79. unsigned len, unsigned flags, struct page **pagep,
  80. void **fsdata)
  81. {
  82. struct page *page;
  83. if (WARN_ON_ONCE(pos >= PAGE_SIZE))
  84. return -EIO;
  85. page = grab_cache_page_write_begin(mapping, 0, flags);
  86. if (!page)
  87. return -ENOMEM;
  88. *pagep = page;
  89. if (!PageUptodate(page))
  90. __udf_adinicb_readpage(page);
  91. return 0;
  92. }
  93. static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
  94. {
  95. /* Fallback to buffered I/O. */
  96. return 0;
  97. }
  98. static int udf_adinicb_write_end(struct file *file, struct address_space *mapping,
  99. loff_t pos, unsigned len, unsigned copied,
  100. struct page *page, void *fsdata)
  101. {
  102. struct inode *inode = page->mapping->host;
  103. loff_t last_pos = pos + copied;
  104. if (last_pos > inode->i_size)
  105. i_size_write(inode, last_pos);
  106. set_page_dirty(page);
  107. unlock_page(page);
  108. put_page(page);
  109. return copied;
  110. }
  111. const struct address_space_operations udf_adinicb_aops = {
  112. .readpage = udf_adinicb_readpage,
  113. .writepage = udf_adinicb_writepage,
  114. .write_begin = udf_adinicb_write_begin,
  115. .write_end = udf_adinicb_write_end,
  116. .direct_IO = udf_adinicb_direct_IO,
  117. };
  118. static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
  119. {
  120. ssize_t retval;
  121. struct file *file = iocb->ki_filp;
  122. struct inode *inode = file_inode(file);
  123. struct udf_inode_info *iinfo = UDF_I(inode);
  124. int err;
  125. inode_lock(inode);
  126. retval = generic_write_checks(iocb, from);
  127. if (retval <= 0)
  128. goto out;
  129. down_write(&iinfo->i_data_sem);
  130. if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
  131. loff_t end = iocb->ki_pos + iov_iter_count(from);
  132. if (inode->i_sb->s_blocksize <
  133. (udf_file_entry_alloc_offset(inode) + end)) {
  134. err = udf_expand_file_adinicb(inode);
  135. if (err) {
  136. inode_unlock(inode);
  137. udf_debug("udf_expand_adinicb: err=%d\n", err);
  138. return err;
  139. }
  140. } else {
  141. iinfo->i_lenAlloc = max(end, inode->i_size);
  142. up_write(&iinfo->i_data_sem);
  143. }
  144. } else
  145. up_write(&iinfo->i_data_sem);
  146. retval = __generic_file_write_iter(iocb, from);
  147. out:
  148. inode_unlock(inode);
  149. if (retval > 0) {
  150. mark_inode_dirty(inode);
  151. retval = generic_write_sync(iocb, retval);
  152. }
  153. return retval;
  154. }
  155. long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  156. {
  157. struct inode *inode = file_inode(filp);
  158. long old_block, new_block;
  159. int result;
  160. if (inode_permission(inode, MAY_READ) != 0) {
  161. udf_debug("no permission to access inode %lu\n", inode->i_ino);
  162. return -EPERM;
  163. }
  164. if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) ||
  165. (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) {
  166. udf_debug("invalid argument to udf_ioctl\n");
  167. return -EINVAL;
  168. }
  169. switch (cmd) {
  170. case UDF_GETVOLIDENT:
  171. if (copy_to_user((char __user *)arg,
  172. UDF_SB(inode->i_sb)->s_volume_ident, 32))
  173. return -EFAULT;
  174. return 0;
  175. case UDF_RELOCATE_BLOCKS:
  176. if (!capable(CAP_SYS_ADMIN))
  177. return -EPERM;
  178. if (get_user(old_block, (long __user *)arg))
  179. return -EFAULT;
  180. result = udf_relocate_blocks(inode->i_sb,
  181. old_block, &new_block);
  182. if (result == 0)
  183. result = put_user(new_block, (long __user *)arg);
  184. return result;
  185. case UDF_GETEASIZE:
  186. return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
  187. case UDF_GETEABLOCK:
  188. return copy_to_user((char __user *)arg,
  189. UDF_I(inode)->i_data,
  190. UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
  191. default:
  192. return -ENOIOCTLCMD;
  193. }
  194. return 0;
  195. }
  196. static int udf_release_file(struct inode *inode, struct file *filp)
  197. {
  198. if (filp->f_mode & FMODE_WRITE &&
  199. atomic_read(&inode->i_writecount) == 1) {
  200. /*
  201. * Grab i_mutex to avoid races with writes changing i_size
  202. * while we are running.
  203. */
  204. inode_lock(inode);
  205. down_write(&UDF_I(inode)->i_data_sem);
  206. udf_discard_prealloc(inode);
  207. udf_truncate_tail_extent(inode);
  208. up_write(&UDF_I(inode)->i_data_sem);
  209. inode_unlock(inode);
  210. }
  211. return 0;
  212. }
  213. const struct file_operations udf_file_operations = {
  214. .read_iter = generic_file_read_iter,
  215. .unlocked_ioctl = udf_ioctl,
  216. .open = generic_file_open,
  217. .mmap = generic_file_mmap,
  218. .write_iter = udf_file_write_iter,
  219. .release = udf_release_file,
  220. .fsync = generic_file_fsync,
  221. .splice_read = generic_file_splice_read,
  222. .llseek = generic_file_llseek,
  223. };
  224. static int udf_setattr(struct dentry *dentry, struct iattr *attr)
  225. {
  226. struct inode *inode = d_inode(dentry);
  227. struct super_block *sb = inode->i_sb;
  228. int error;
  229. error = setattr_prepare(dentry, attr);
  230. if (error)
  231. return error;
  232. if ((attr->ia_valid & ATTR_UID) &&
  233. UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET) &&
  234. !uid_eq(attr->ia_uid, UDF_SB(sb)->s_uid))
  235. return -EPERM;
  236. if ((attr->ia_valid & ATTR_GID) &&
  237. UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET) &&
  238. !gid_eq(attr->ia_gid, UDF_SB(sb)->s_gid))
  239. return -EPERM;
  240. if ((attr->ia_valid & ATTR_SIZE) &&
  241. attr->ia_size != i_size_read(inode)) {
  242. error = udf_setsize(inode, attr->ia_size);
  243. if (error)
  244. return error;
  245. }
  246. if (attr->ia_valid & ATTR_MODE)
  247. udf_update_extra_perms(inode, attr->ia_mode);
  248. setattr_copy(inode, attr);
  249. mark_inode_dirty(inode);
  250. return 0;
  251. }
  252. const struct inode_operations udf_file_inode_operations = {
  253. .setattr = udf_setattr,
  254. };