ext4: fold __mpage_da_writepage() into write_cache_pages_da()
Fold the __mpage_da_writepage() function into write_cache_pages_da(). This will give us opportunities to clean up and simplify the resulting code. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o
parent
6fd7a46781
commit
8eb9e5ce21
1 changed files with 91 additions and 115 deletions
204
fs/ext4/inode.c
204
fs/ext4/inode.c
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@ -2437,102 +2437,6 @@ static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
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return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
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}
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/*
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* __mpage_da_writepage - finds extent of pages and blocks
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*
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* @page: page to consider
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* @wbc: not used, we just follow rules
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* @data: context
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*
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* The function finds extents of pages and scan them for all blocks.
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*/
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static int __mpage_da_writepage(struct page *page,
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struct writeback_control *wbc,
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struct mpage_da_data *mpd)
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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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/*
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* Can we merge this page to current extent?
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*/
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if (mpd->next_page != page->index) {
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/*
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* Nope, we can't. So, we map non-allocated blocks
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* and start IO on them
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*/
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if (mpd->next_page != mpd->first_page) {
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mpage_da_map_and_submit(mpd);
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/*
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* skip rest of the page in the page_vec
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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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return MPAGE_DA_EXTENT_TAIL;
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}
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/*
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* Start next extent of pages ...
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*/
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mpd->first_page = page->index;
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/*
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* ... and blocks
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*/
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mpd->b_size = 0;
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mpd->b_state = 0;
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mpd->b_blocknr = 0;
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}
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mpd->next_page = page->index + 1;
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logical = (sector_t) page->index <<
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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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(1 << BH_Dirty) | (1 << BH_Uptodate));
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if (mpd->io_done)
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return MPAGE_DA_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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*/
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head = page_buffers(page);
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bh = head;
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do {
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BUG_ON(buffer_locked(bh));
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/*
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* We need to try to allocate
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* unmapped blocks in the same page.
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* Otherwise we won't make progress
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* with the page in ext4_writepage
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*/
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if (ext4_bh_delay_or_unwritten(NULL, bh)) {
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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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return MPAGE_DA_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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*/
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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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}
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logical++;
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} while ((bh = bh->b_this_page) != head);
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}
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return 0;
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}
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/*
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* This is a special get_blocks_t callback which is used by
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* ext4_da_write_begin(). It will either return mapped block or
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@ -2811,18 +2715,17 @@ static int ext4_da_writepages_trans_blocks(struct inode *inode)
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/*
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* write_cache_pages_da - walk the list of dirty pages of the given
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* address space and call the callback function (which usually writes
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* the pages).
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*
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* This is a forked version of write_cache_pages(). Differences:
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* Range cyclic is ignored.
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* no_nrwrite_index_update is always presumed true
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* address space and accumulate pages that need writing, and call
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* mpage_da_map_and_submit to map the pages and then write them.
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*/
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static int write_cache_pages_da(struct address_space *mapping,
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struct writeback_control *wbc,
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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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@ -2899,16 +2802,89 @@ continue_unlock:
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if (!clear_page_dirty_for_io(page))
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goto continue_unlock;
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ret = __mpage_da_writepage(page, wbc, mpd);
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if (unlikely(ret)) {
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if (ret == AOP_WRITEPAGE_ACTIVATE) {
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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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if (mpd->next_page != page->index) {
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/*
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* Nope, we can't. So, we map
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* non-allocated blocks and start IO
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* on them
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*/
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if (mpd->next_page != mpd->first_page) {
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mpage_da_map_and_submit(mpd);
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/*
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* skip rest of the page in the page_vec
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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 = 0;
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ret = MPAGE_DA_EXTENT_TAIL;
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goto out;
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}
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/*
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* Start next extent of pages and blocks
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*/
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mpd->first_page = page->index;
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mpd->b_size = 0;
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mpd->b_state = 0;
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mpd->b_blocknr = 0;
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}
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mpd->next_page = page->index + 1;
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logical = (sector_t) page->index <<
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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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(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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} else {
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done = 1;
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break;
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/*
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* Page with regular buffer heads, 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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do {
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BUG_ON(buffer_locked(bh));
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/*
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* We need to try to allocate
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* unmapped blocks in the same page.
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* Otherwise we won't make progress
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* with the page in ext4_writepage
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*/
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if (ext4_bh_delay_or_unwritten(NULL, bh)) {
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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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} 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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*/
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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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}
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logical++;
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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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@ -2933,6 +2909,10 @@ continue_unlock:
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cond_resched();
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}
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return ret;
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out:
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pagevec_release(&pvec);
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cond_resched();
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return ret;
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}
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@ -3059,13 +3039,9 @@ retry:
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}
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/*
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* Now call __mpage_da_writepage to find the next
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* Now call write_cache_pages_da() to find the next
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* contiguous region of logical blocks that need
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* blocks to be allocated by ext4. We don't actually
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* submit the blocks for I/O here, even though
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* write_cache_pages thinks it will, and will set the
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* pages as clean for write before calling
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* __mpage_da_writepage().
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* blocks to be allocated by ext4 and submit them.
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*/
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mpd.b_size = 0;
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mpd.b_state = 0;
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