ext4: simple cleanups to write_cache_pages_da()
Eliminate duplicate code, unneeded variables, etc., to make it easier to understand the code. No behavioral changes were made in this patch. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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parent
8eb9e5ce21
commit
4f01b02c8c
115
fs/ext4/inode.c
115
fs/ext4/inode.c
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@ -2723,17 +2723,14 @@ static int write_cache_pages_da(struct address_space *mapping,
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struct mpage_da_data *mpd,
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pgoff_t *done_index)
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{
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struct inode *inode = mpd->inode;
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struct buffer_head *bh, *head;
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sector_t logical;
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int ret = 0;
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int done = 0;
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struct pagevec pvec;
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unsigned nr_pages;
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pgoff_t index;
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pgoff_t end; /* Inclusive */
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long nr_to_write = wbc->nr_to_write;
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int tag;
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struct buffer_head *bh, *head;
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struct inode *inode = mpd->inode;
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struct pagevec pvec;
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unsigned int nr_pages;
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sector_t logical;
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pgoff_t index, end;
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long nr_to_write = wbc->nr_to_write;
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int i, tag, ret = 0;
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pagevec_init(&pvec, 0);
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index = wbc->range_start >> PAGE_CACHE_SHIFT;
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@ -2745,13 +2742,11 @@ static int write_cache_pages_da(struct address_space *mapping,
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tag = PAGECACHE_TAG_DIRTY;
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*done_index = index;
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while (!done && (index <= end)) {
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int i;
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while (index <= end) {
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nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
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min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
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if (nr_pages == 0)
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break;
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return 0;
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for (i = 0; i < nr_pages; i++) {
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struct page *page = pvec.pages[i];
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@ -2763,47 +2758,37 @@ static int write_cache_pages_da(struct address_space *mapping,
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* mapping. However, page->index will not change
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* because we have a reference on the page.
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*/
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if (page->index > end) {
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done = 1;
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break;
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}
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if (page->index > end)
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goto out;
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*done_index = page->index + 1;
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lock_page(page);
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/*
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* Page truncated or invalidated. We can freely skip it
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* then, even for data integrity operations: the page
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* has disappeared concurrently, so there could be no
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* real expectation of this data interity operation
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* even if there is now a new, dirty page at the same
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* pagecache address.
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* If the page is no longer dirty, or its
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* mapping no longer corresponds to inode we
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* are writing (which means it has been
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* truncated or invalidated), or the page is
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* already under writeback and we are not
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* doing a data integrity writeback, skip the page
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*/
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if (unlikely(page->mapping != mapping)) {
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continue_unlock:
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if (!PageDirty(page) ||
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(PageWriteback(page) &&
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(wbc->sync_mode == WB_SYNC_NONE)) ||
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unlikely(page->mapping != mapping)) {
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continue_unlock:
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unlock_page(page);
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continue;
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}
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if (!PageDirty(page)) {
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/* someone wrote it for us */
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goto continue_unlock;
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}
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if (PageWriteback(page)) {
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if (wbc->sync_mode != WB_SYNC_NONE)
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wait_on_page_writeback(page);
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else
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goto continue_unlock;
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}
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if (PageWriteback(page))
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wait_on_page_writeback(page);
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BUG_ON(PageWriteback(page));
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if (!clear_page_dirty_for_io(page))
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goto continue_unlock;
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/* BEGIN __mpage_da_writepage */
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/*
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* Can we merge this page to current extent?
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*/
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@ -2820,8 +2805,7 @@ continue_unlock:
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*/
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redirty_page_for_writepage(wbc, page);
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unlock_page(page);
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ret = MPAGE_DA_EXTENT_TAIL;
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goto out;
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goto ret_extent_tail;
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}
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/*
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@ -2838,15 +2822,15 @@ continue_unlock:
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(PAGE_CACHE_SHIFT - inode->i_blkbits);
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if (!page_has_buffers(page)) {
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mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE,
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mpage_add_bh_to_extent(mpd, logical,
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PAGE_CACHE_SIZE,
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(1 << BH_Dirty) | (1 << BH_Uptodate));
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if (mpd->io_done) {
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ret = MPAGE_DA_EXTENT_TAIL;
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goto out;
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}
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if (mpd->io_done)
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goto ret_extent_tail;
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} else {
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/*
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* Page with regular buffer heads, just add all dirty ones
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* Page with regular buffer heads,
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* just add all dirty ones
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*/
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head = page_buffers(page);
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bh = head;
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@ -2862,18 +2846,19 @@ continue_unlock:
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mpage_add_bh_to_extent(mpd, logical,
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bh->b_size,
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bh->b_state);
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if (mpd->io_done) {
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ret = MPAGE_DA_EXTENT_TAIL;
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goto out;
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}
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if (mpd->io_done)
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goto ret_extent_tail;
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} else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
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/*
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* mapped dirty buffer. We need to update
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* the b_state because we look at
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* b_state in mpage_da_map_blocks. We don't
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* update b_size because if we find an
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* unmapped buffer_head later we need to
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* use the b_state flag of that buffer_head.
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* mapped dirty buffer. We need
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* to update the b_state
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* because we look at b_state
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* in mpage_da_map_blocks. We
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* don't update b_size because
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* if we find an unmapped
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* buffer_head later we need to
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* use the b_state flag of that
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* buffer_head.
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*/
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if (mpd->b_size == 0)
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mpd->b_state = bh->b_state & BH_FLAGS;
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@ -2882,14 +2867,10 @@ continue_unlock:
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} while ((bh = bh->b_this_page) != head);
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}
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ret = 0;
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/* END __mpage_da_writepage */
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if (nr_to_write > 0) {
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nr_to_write--;
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if (nr_to_write == 0 &&
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wbc->sync_mode == WB_SYNC_NONE) {
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wbc->sync_mode == WB_SYNC_NONE)
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/*
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* We stop writing back only if we are
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* not doing integrity sync. In case of
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@ -2900,15 +2881,15 @@ continue_unlock:
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* pages, but have not synced all of the
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* old dirty pages.
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*/
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done = 1;
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break;
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}
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goto out;
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}
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}
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pagevec_release(&pvec);
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cond_resched();
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}
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return ret;
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return 0;
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ret_extent_tail:
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ret = MPAGE_DA_EXTENT_TAIL;
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out:
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pagevec_release(&pvec);
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cond_resched();
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