-/*
- * __mpage_da_writepage - finds extent of pages and blocks
- *
- * @page: page to consider
- * @wbc: not used, we just follow rules
- * @data: context
- *
- * The function finds extents of pages and scan them for all blocks.
- */
-static int __mpage_da_writepage(struct page *page,
- struct writeback_control *wbc,
- struct mpage_da_data *mpd)
-{
- struct inode *inode = mpd->inode;
- struct buffer_head *bh, *head;
- sector_t logical;
-
- /*
- * Can we merge this page to current extent?
- */
- if (mpd->next_page != page->index) {
- /*
- * Nope, we can't. So, we map non-allocated blocks
- * and start IO on them
- */
- if (mpd->next_page != mpd->first_page) {
- mpage_da_map_and_submit(mpd);
- /*
- * skip rest of the page in the page_vec
- */
- redirty_page_for_writepage(wbc, page);
- unlock_page(page);
- return MPAGE_DA_EXTENT_TAIL;
- }
-
- /*
- * Start next extent of pages ...
- */
- mpd->first_page = page->index;
-
- /*
- * ... and blocks
- */
- mpd->b_size = 0;
- mpd->b_state = 0;
- mpd->b_blocknr = 0;
- }
-
- mpd->next_page = page->index + 1;
- logical = (sector_t) page->index <<
- (PAGE_CACHE_SHIFT - inode->i_blkbits);
-
- if (!page_has_buffers(page)) {
- mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE,
- (1 << BH_Dirty) | (1 << BH_Uptodate));
- if (mpd->io_done)
- return MPAGE_DA_EXTENT_TAIL;
- } else {
- /*
- * Page with regular buffer heads, just add all dirty ones
- */
- head = page_buffers(page);
- bh = head;
- do {
- BUG_ON(buffer_locked(bh));
- /*
- * We need to try to allocate
- * unmapped blocks in the same page.
- * Otherwise we won't make progress
- * with the page in ext4_writepage
- */
- if (ext4_bh_delay_or_unwritten(NULL, bh)) {
- mpage_add_bh_to_extent(mpd, logical,
- bh->b_size,
- bh->b_state);
- if (mpd->io_done)
- return MPAGE_DA_EXTENT_TAIL;
- } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
- /*
- * mapped dirty buffer. We need to update
- * the b_state because we look at
- * b_state in mpage_da_map_blocks. We don't
- * update b_size because if we find an
- * unmapped buffer_head later we need to
- * use the b_state flag of that buffer_head.
- */
- if (mpd->b_size == 0)
- mpd->b_state = bh->b_state & BH_FLAGS;
- }
- logical++;
- } while ((bh = bh->b_this_page) != head);
- }
-
- return 0;
-}
-