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Message-Id: <1287761366-20249-6-git-send-email-tytso@mit.edu>
Date: Fri, 22 Oct 2010 11:29:25 -0400
From: Theodore Ts'o <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: Theodore Ts'o <tytso@....edu>
Subject: [PATCH 5/6] ext4: move mpage_put_bnr_to_bhs()'s functionality to mpage_da_submit_io()
This massively simplifies the ext4_da_writepages() code path by
completely removing mpage_put_bnr_bhs(), which is almost 100 lines of
code iterating over a set of pages using pagevec_lookup(), and folds
that functionality into mpage_da_submit_io()'s existing
pagevec_lookup() loop.
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
fs/ext4/inode.c | 139 +++++++++++++++----------------------------------------
1 files changed, 38 insertions(+), 101 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9fda16c..93668ca 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2003,7 +2003,8 @@ static void ext4_da_page_release_reservation(struct page *page,
*
* As pages are already locked by write_cache_pages(), we can't use it
*/
-static int mpage_da_submit_io(struct mpage_da_data *mpd)
+static int mpage_da_submit_io(struct mpage_da_data *mpd,
+ struct ext4_map_blocks *map)
{
struct pagevec pvec;
unsigned long index, end;
@@ -2014,6 +2015,7 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
unsigned int len, block_start;
struct buffer_head *bh, *page_bufs = NULL;
int journal_data = ext4_should_journal_data(inode);
+ sector_t pblock = 0, cur_logical = 0;
BUG_ON(mpd->next_page <= mpd->first_page);
/*
@@ -2031,7 +2033,7 @@ 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;
+ int commit_write = 0, redirty_page = 0;
struct page *page = pvec.pages[i];
index = page->index;
@@ -2042,6 +2044,12 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
len = size & ~PAGE_CACHE_MASK;
else
len = PAGE_CACHE_SIZE;
+ if (map) {
+ cur_logical = index << (PAGE_CACHE_SHIFT -
+ inode->i_blkbits);
+ pblock = map->m_pblk + (cur_logical -
+ map->m_lblk);
+ }
index++;
BUG_ON(!PageLocked(page));
@@ -2068,13 +2076,34 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
bh = page_bufs = page_buffers(page);
block_start = 0;
do {
- /* redirty page if block allocation undone */
- if (!bh || buffer_delay(bh) ||
- buffer_unwritten(bh))
+ if (!bh)
goto redirty_page;
+ if (map && (cur_logical >= map->m_lblk) &&
+ (cur_logical <= (map->m_lblk +
+ (map->m_len - 1)))) {
+ if (buffer_delay(bh)) {
+ clear_buffer_delay(bh);
+ bh->b_blocknr = pblock;
+ }
+ if (buffer_unwritten(bh) ||
+ buffer_mapped(bh))
+ BUG_ON(bh->b_blocknr != pblock);
+ if (map->m_flags & EXT4_MAP_UNINIT)
+ set_buffer_uninit(bh);
+ clear_buffer_unwritten(bh);
+ }
+
+ /* redirty page if block allocation undone */
+ if (buffer_delay(bh) || buffer_unwritten(bh))
+ redirty_page = 1;
bh = bh->b_this_page;
block_start += bh->b_size;
- } while ((bh != page_bufs) && (block_start < len));
+ cur_logical++;
+ pblock++;
+ } while (bh != page_bufs);
+
+ if (redirty_page)
+ goto redirty_page;
if (commit_write)
/* mark the buffer_heads as dirty & uptodate */
@@ -2105,91 +2134,6 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
return ret;
}
-/*
- * mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers
- *
- * the function goes through all passed space and put actual disk
- * block numbers into buffer heads, dropping BH_Delay and BH_Unwritten
- */
-static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd,
- struct ext4_map_blocks *map)
-{
- struct inode *inode = mpd->inode;
- struct address_space *mapping = inode->i_mapping;
- int blocks = map->m_len;
- sector_t pblock = map->m_pblk, cur_logical;
- struct buffer_head *head, *bh;
- pgoff_t index, end;
- struct pagevec pvec;
- int nr_pages, i;
-
- index = map->m_lblk >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
- end = (map->m_lblk + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
- cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
-
- pagevec_init(&pvec, 0);
-
- while (index <= end) {
- /* XXX: optimize tail */
- nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
- if (nr_pages == 0)
- break;
- for (i = 0; i < nr_pages; i++) {
- struct page *page = pvec.pages[i];
-
- index = page->index;
- if (index > end)
- break;
- index++;
-
- BUG_ON(!PageLocked(page));
- BUG_ON(PageWriteback(page));
- BUG_ON(!page_has_buffers(page));
-
- bh = page_buffers(page);
- head = bh;
-
- /* skip blocks out of the range */
- do {
- if (cur_logical >= map->m_lblk)
- break;
- cur_logical++;
- } while ((bh = bh->b_this_page) != head);
-
- do {
- if (cur_logical > map->m_lblk + (blocks - 1))
- break;
-
- if (buffer_delay(bh) || buffer_unwritten(bh)) {
-
- BUG_ON(bh->b_bdev != inode->i_sb->s_bdev);
-
- if (buffer_delay(bh)) {
- clear_buffer_delay(bh);
- bh->b_blocknr = pblock;
- } else {
- /*
- * unwritten already should have
- * blocknr assigned. Verify that
- */
- clear_buffer_unwritten(bh);
- BUG_ON(bh->b_blocknr != pblock);
- }
-
- } else if (buffer_mapped(bh))
- BUG_ON(bh->b_blocknr != pblock);
-
- if (map->m_flags & EXT4_MAP_UNINIT)
- set_buffer_uninit(bh);
- cur_logical++;
- pblock++;
- } while ((bh = bh->b_this_page) != head);
- }
- pagevec_release(&pvec);
- }
-}
-
-
static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
sector_t logical, long blk_cnt)
{
@@ -2252,7 +2196,7 @@ static void ext4_print_free_blocks(struct inode *inode)
static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
{
int err, blks, get_blocks_flags;
- struct ext4_map_blocks map;
+ struct ext4_map_blocks map, *mapp = NULL;
sector_t next = mpd->b_blocknr;
unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
@@ -2343,6 +2287,7 @@ static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
}
BUG_ON(blks == 0);
+ mapp = ↦
if (map.m_flags & EXT4_MAP_NEW) {
struct block_device *bdev = mpd->inode->i_sb->s_bdev;
int i;
@@ -2351,14 +2296,6 @@ static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
unmap_underlying_metadata(bdev, map.m_pblk + i);
}
- /*
- * If blocks are delayed marked, we need to
- * put actual blocknr and drop delayed bit
- */
- if ((mpd->b_state & (1 << BH_Delay)) ||
- (mpd->b_state & (1 << BH_Unwritten)))
- mpage_put_bnr_to_bhs(mpd, &map);
-
if (ext4_should_order_data(mpd->inode)) {
err = ext4_jbd2_file_inode(handle, mpd->inode);
if (err)
@@ -2379,7 +2316,7 @@ static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
}
submit_io:
- mpage_da_submit_io(mpd);
+ mpage_da_submit_io(mpd, mapp);
mpd->io_done = 1;
}
--
1.7.1
--
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