file.c 7.6 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_read_folio(struct file *file, struct folio *folio)
  56. {
  57. BUG_ON(!folio_test_locked(folio));
  58. __udf_adinicb_readpage(&folio->page);
  59. folio_unlock(folio);
  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, 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);
  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. .dirty_folio = block_dirty_folio,
  113. .invalidate_folio = block_invalidate_folio,
  114. .read_folio = udf_adinicb_read_folio,
  115. .writepage = udf_adinicb_writepage,
  116. .write_begin = udf_adinicb_write_begin,
  117. .write_end = udf_adinicb_write_end,
  118. .direct_IO = udf_adinicb_direct_IO,
  119. };
  120. static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
  121. {
  122. ssize_t retval;
  123. struct file *file = iocb->ki_filp;
  124. struct inode *inode = file_inode(file);
  125. struct udf_inode_info *iinfo = UDF_I(inode);
  126. int err;
  127. inode_lock(inode);
  128. retval = generic_write_checks(iocb, from);
  129. if (retval <= 0)
  130. goto out;
  131. down_write(&iinfo->i_data_sem);
  132. if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB &&
  133. inode->i_sb->s_blocksize < (udf_file_entry_alloc_offset(inode) +
  134. iocb->ki_pos + iov_iter_count(from))) {
  135. err = udf_expand_file_adinicb(inode);
  136. if (err) {
  137. inode_unlock(inode);
  138. udf_debug("udf_expand_adinicb: err=%d\n", err);
  139. return err;
  140. }
  141. } else
  142. up_write(&iinfo->i_data_sem);
  143. retval = __generic_file_write_iter(iocb, from);
  144. out:
  145. down_write(&iinfo->i_data_sem);
  146. if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB && retval > 0)
  147. iinfo->i_lenAlloc = inode->i_size;
  148. up_write(&iinfo->i_data_sem);
  149. inode_unlock(inode);
  150. if (retval > 0) {
  151. mark_inode_dirty(inode);
  152. retval = generic_write_sync(iocb, retval);
  153. }
  154. return retval;
  155. }
  156. long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  157. {
  158. struct inode *inode = file_inode(filp);
  159. long old_block, new_block;
  160. int result;
  161. if (file_permission(filp, MAY_READ) != 0) {
  162. udf_debug("no permission to access inode %lu\n", inode->i_ino);
  163. return -EPERM;
  164. }
  165. if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) ||
  166. (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) {
  167. udf_debug("invalid argument to udf_ioctl\n");
  168. return -EINVAL;
  169. }
  170. switch (cmd) {
  171. case UDF_GETVOLIDENT:
  172. if (copy_to_user((char __user *)arg,
  173. UDF_SB(inode->i_sb)->s_volume_ident, 32))
  174. return -EFAULT;
  175. return 0;
  176. case UDF_RELOCATE_BLOCKS:
  177. if (!capable(CAP_SYS_ADMIN))
  178. return -EPERM;
  179. if (get_user(old_block, (long __user *)arg))
  180. return -EFAULT;
  181. result = udf_relocate_blocks(inode->i_sb,
  182. old_block, &new_block);
  183. if (result == 0)
  184. result = put_user(new_block, (long __user *)arg);
  185. return result;
  186. case UDF_GETEASIZE:
  187. return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
  188. case UDF_GETEABLOCK:
  189. return copy_to_user((char __user *)arg,
  190. UDF_I(inode)->i_data,
  191. UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
  192. default:
  193. return -ENOIOCTLCMD;
  194. }
  195. return 0;
  196. }
  197. static int udf_release_file(struct inode *inode, struct file *filp)
  198. {
  199. if (filp->f_mode & FMODE_WRITE &&
  200. atomic_read(&inode->i_writecount) == 1) {
  201. /*
  202. * Grab i_mutex to avoid races with writes changing i_size
  203. * while we are running.
  204. */
  205. inode_lock(inode);
  206. down_write(&UDF_I(inode)->i_data_sem);
  207. udf_discard_prealloc(inode);
  208. udf_truncate_tail_extent(inode);
  209. up_write(&UDF_I(inode)->i_data_sem);
  210. inode_unlock(inode);
  211. }
  212. return 0;
  213. }
  214. const struct file_operations udf_file_operations = {
  215. .read_iter = generic_file_read_iter,
  216. .unlocked_ioctl = udf_ioctl,
  217. .open = generic_file_open,
  218. .mmap = generic_file_mmap,
  219. .write_iter = udf_file_write_iter,
  220. .release = udf_release_file,
  221. .fsync = generic_file_fsync,
  222. .splice_read = generic_file_splice_read,
  223. .splice_write = iter_file_splice_write,
  224. .llseek = generic_file_llseek,
  225. };
  226. static int udf_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
  227. struct iattr *attr)
  228. {
  229. struct inode *inode = d_inode(dentry);
  230. struct super_block *sb = inode->i_sb;
  231. int error;
  232. error = setattr_prepare(&init_user_ns, dentry, attr);
  233. if (error)
  234. return error;
  235. if ((attr->ia_valid & ATTR_UID) &&
  236. UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET) &&
  237. !uid_eq(attr->ia_uid, UDF_SB(sb)->s_uid))
  238. return -EPERM;
  239. if ((attr->ia_valid & ATTR_GID) &&
  240. UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET) &&
  241. !gid_eq(attr->ia_gid, UDF_SB(sb)->s_gid))
  242. return -EPERM;
  243. if ((attr->ia_valid & ATTR_SIZE) &&
  244. attr->ia_size != i_size_read(inode)) {
  245. error = udf_setsize(inode, attr->ia_size);
  246. if (error)
  247. return error;
  248. }
  249. if (attr->ia_valid & ATTR_MODE)
  250. udf_update_extra_perms(inode, attr->ia_mode);
  251. setattr_copy(&init_user_ns, inode, attr);
  252. mark_inode_dirty(inode);
  253. return 0;
  254. }
  255. const struct inode_operations udf_file_inode_operations = {
  256. .setattr = udf_setattr,
  257. };