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Message-Id: <1287761366-20249-4-git-send-email-tytso@mit.edu>
Date: Fri, 22 Oct 2010 11:29:23 -0400
From: Theodore Ts'o <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: Theodore Ts'o <tytso@....edu>
Subject: [PATCH 3/6] ext4: inline ext4_writepage() into mpage_da_submit_io()
As a prepratory step to switching to bio_submit, inline
ext4_writepage() into mpage_da_submit() and then simplify things a
bit. This makes it clearer what mpage_da_submit needs to do.
Also, move the ClearPageChecked(page) call into
__ext4_journalled_writepage(), as a minor bit of cleanup refactoring.
This also allows us to pull i_size_read() and
ext4_should_journal_data() out of the loop, which should be a very
minor CPU savings.
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
fs/ext4/inode.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 59 insertions(+), 11 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 58b7008..f97fc46 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -60,7 +60,12 @@ static inline int ext4_begin_ordered_truncate(struct inode *inode,
}
static void ext4_invalidatepage(struct page *page, unsigned long offset);
-static int ext4_writepage(struct page *page, struct writeback_control *wbc);
+static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create);
+static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
+static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
+static int __ext4_journalled_writepage(struct page *page, unsigned int len);
+static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
/*
* Test whether an inode is a fast symlink.
@@ -2000,12 +2005,15 @@ static void ext4_da_page_release_reservation(struct page *page,
*/
static int mpage_da_submit_io(struct mpage_da_data *mpd)
{
- long pages_skipped;
struct pagevec pvec;
unsigned long index, end;
int ret = 0, err, nr_pages, i;
struct inode *inode = mpd->inode;
struct address_space *mapping = inode->i_mapping;
+ loff_t size = i_size_read(inode);
+ unsigned int len;
+ struct buffer_head *page_bufs = NULL;
+ int journal_data = ext4_should_journal_data(inode);
BUG_ON(mpd->next_page <= mpd->first_page);
/*
@@ -2023,28 +2031,69 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
if (nr_pages == 0)
break;
for (i = 0; i < nr_pages; i++) {
+ int commit_write = 0;
struct page *page = pvec.pages[i];
index = page->index;
if (index > end)
break;
+
+ if (index == size >> PAGE_CACHE_SHIFT)
+ len = size & ~PAGE_CACHE_MASK;
+ else
+ len = PAGE_CACHE_SIZE;
index++;
BUG_ON(!PageLocked(page));
BUG_ON(PageWriteback(page));
- pages_skipped = mpd->wbc->pages_skipped;
- err = ext4_writepage(page, mpd->wbc);
- if (!err && (pages_skipped == mpd->wbc->pages_skipped))
+ /*
+ * If the page does not have buffers (for
+ * whatever reason), try to create them using
+ * block_prepare_write. If this fails,
+ * redirty the page and move on.
+ */
+ if (!page_has_buffers(page)) {
+ if (block_prepare_write(page, 0, len,
+ noalloc_get_block_write)) {
+ redirty_page:
+ redirty_page_for_writepage(mpd->wbc,
+ page);
+ unlock_page(page);
+ continue;
+ }
+ commit_write = 1;
+ }
+ page_bufs = page_buffers(page);
+ if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
+ ext4_bh_delay_or_unwritten)) {
/*
- * have successfully written the page
- * without skipping the same
+ * We couldn't do block allocation for
+ * some reason.
*/
+ goto redirty_page;
+ }
+
+ if (commit_write)
+ /* mark the buffer_heads as dirty & uptodate */
+ block_commit_write(page, 0, len);
+
+ if (journal_data && PageChecked(page))
+ err = __ext4_journalled_writepage(page, len);
+ else if (buffer_uninit(page_bufs)) {
+ ext4_set_bh_endio(page_bufs, inode);
+ err = block_write_full_page_endio(page,
+ noalloc_get_block_write,
+ mpd->wbc, ext4_end_io_buffer_write);
+ } else
+ err = block_write_full_page(page,
+ noalloc_get_block_write, mpd->wbc);
+
+ if (!err)
mpd->pages_written++;
/*
* In error case, we have to continue because
* remaining pages are still locked
- * XXX: unlock and re-dirty them?
*/
if (ret == 0)
ret = err;
@@ -2624,6 +2673,7 @@ static int __ext4_journalled_writepage(struct page *page,
int ret = 0;
int err;
+ ClearPageChecked(page);
page_bufs = page_buffers(page);
BUG_ON(!page_bufs);
walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
@@ -2746,14 +2796,12 @@ static int ext4_writepage(struct page *page,
/* now mark the buffer_heads as dirty and uptodate */
block_commit_write(page, 0, len);
- if (PageChecked(page) && ext4_should_journal_data(inode)) {
+ if (PageChecked(page) && ext4_should_journal_data(inode))
/*
* It's mmapped pagecache. Add buffers and journal it. There
* doesn't seem much point in redirtying the page here.
*/
- ClearPageChecked(page);
return __ext4_journalled_writepage(page, len);
- }
if (buffer_uninit(page_bufs)) {
ext4_set_bh_endio(page_bufs, inode);
--
1.7.1
--
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