- int retval = 0;
- int index ;
- struct page *page ;
- struct address_space *mapping ;
- unsigned long write_from ;
- unsigned long blocksize = inode->i_sb->s_blocksize ;
-
- if (inode->i_size == 0) {
- REISERFS_I(inode)->i_flags |= i_nopack_mask;
- return 0 ;
- }
- /* ioctl already done */
- if (REISERFS_I(inode)->i_flags & i_nopack_mask) {
- return 0 ;
- }
- reiserfs_write_lock(inode->i_sb);
-
- /* we need to make sure nobody is changing the file size beneath
- ** us
- */
- down(&inode->i_sem) ;
-
- write_from = inode->i_size & (blocksize - 1) ;
- /* if we are on a block boundary, we are already unpacked. */
- if ( write_from == 0) {
+ int retval = 0;
+ int index;
+ struct page *page;
+ struct address_space *mapping;
+ unsigned long write_from;
+ unsigned long blocksize = inode->i_sb->s_blocksize;
+
+ if (inode->i_size == 0) {
+ REISERFS_I(inode)->i_flags |= i_nopack_mask;
+ return 0;
+ }
+ /* ioctl already done */
+ if (REISERFS_I(inode)->i_flags & i_nopack_mask) {
+ return 0;
+ }
+
+ /* we need to make sure nobody is changing the file size beneath
+ ** us
+ */
+ mutex_lock(&inode->i_mutex);
+ reiserfs_write_lock(inode->i_sb);
+
+ write_from = inode->i_size & (blocksize - 1);
+ /* if we are on a block boundary, we are already unpacked. */
+ if (write_from == 0) {
+ REISERFS_I(inode)->i_flags |= i_nopack_mask;
+ goto out;
+ }
+
+ /* we unpack by finding the page with the tail, and calling
+ ** reiserfs_prepare_write on that page. This will force a
+ ** reiserfs_get_block to unpack the tail for us.
+ */
+ index = inode->i_size >> PAGE_CACHE_SHIFT;
+ mapping = inode->i_mapping;
+ page = grab_cache_page(mapping, index);
+ retval = -ENOMEM;
+ if (!page) {
+ goto out;
+ }
+ retval =
+ mapping->a_ops->prepare_write(NULL, page, write_from, write_from);
+ if (retval)
+ goto out_unlock;
+
+ /* conversion can change page contents, must flush */
+ flush_dcache_page(page);
+ retval =
+ mapping->a_ops->commit_write(NULL, page, write_from, write_from);