From: Theodore Ts'o Subject: [PATCH,RFC 1/7] ext4: fold __mpage_da_writepage() into write_cache_pages_da() Date: Sat, 12 Feb 2011 19:15:51 -0500 Message-ID: <1297556157-21559-2-git-send-email-tytso@mit.edu> References: <1297556157-21559-1-git-send-email-tytso@mit.edu> Cc: Theodore Ts'o To: Ext4 Developers List Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:38173 "EHLO test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753312Ab1BMA5Y (ORCPT ); Sat, 12 Feb 2011 19:57:24 -0500 In-Reply-To: <1297556157-21559-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: 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" --- fs/ext4/inode.c | 206 ++++++++++++++++++++++++------------------------------- 1 files changed, 91 insertions(+), 115 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 9f7f9e4..627729f 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2438,102 +2438,6 @@ static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh) } /* - * __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; -} - -/* * This is a special get_blocks_t callback which is used by * ext4_da_write_begin(). It will either return mapped block or * reserve space for a single block. @@ -2811,18 +2715,17 @@ static int ext4_da_writepages_trans_blocks(struct inode *inode) /* * write_cache_pages_da - walk the list of dirty pages of the given - * address space and call the callback function (which usually writes - * the pages). - * - * This is a forked version of write_cache_pages(). Differences: - * Range cyclic is ignored. - * no_nrwrite_index_update is always presumed true + * address space and accumulate pages that need writing, and call + * mpage_da_map_and_submit to map the pages and then write them. */ static int write_cache_pages_da(struct address_space *mapping, struct writeback_control *wbc, struct mpage_da_data *mpd, pgoff_t *done_index) { + struct inode *inode = mpd->inode; + struct buffer_head *bh, *head; + sector_t logical; int ret = 0; int done = 0; struct pagevec pvec; @@ -2899,17 +2802,90 @@ continue_unlock: if (!clear_page_dirty_for_io(page)) goto continue_unlock; - ret = __mpage_da_writepage(page, wbc, mpd); - if (unlikely(ret)) { - if (ret == AOP_WRITEPAGE_ACTIVATE) { + /* BEGIN __mpage_da_writepage */ + + /* + * 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); - ret = 0; - } else { - done = 1; - break; + ret = MPAGE_DA_EXTENT_TAIL; + goto out; + } + + /* + * Start next extent of pages and blocks + */ + mpd->first_page = page->index; + 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) { + ret = MPAGE_DA_EXTENT_TAIL; + goto out; } + } 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) { + ret = MPAGE_DA_EXTENT_TAIL; + goto out; + } + } 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); } + ret = 0; + + /* END __mpage_da_writepage */ + if (nr_to_write > 0) { nr_to_write--; if (nr_to_write == 0 && @@ -2933,6 +2909,10 @@ continue_unlock: cond_resched(); } return ret; +out: + pagevec_release(&pvec); + cond_resched(); + return ret; } @@ -3059,13 +3039,9 @@ retry: } /* - * Now call __mpage_da_writepage to find the next + * Now call write_cache_pages_da() to find the next * contiguous region of logical blocks that need - * blocks to be allocated by ext4. We don't actually - * submit the blocks for I/O here, even though - * write_cache_pages thinks it will, and will set the - * pages as clean for write before calling - * __mpage_da_writepage(). + * blocks to be allocated by ext4 and submit them. */ mpd.b_size = 0; mpd.b_state = 0; -- 1.7.3.1