[PATCH] 2.6.11-mm1 ext3 writepages support for writeback mode

[PATCH] 2.6.11-mm1 ext3 writepages support for writeback mode

[Badari Pulavarty]

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Hi Andrew,

Here is the 2.6.11-mm1 patch for adding writepages support
for ext3 writeback mode. Could you include it in -mm tree ?

Thanks,
Badari



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diff -Naurp -X dontdiff linux-2.6.11/fs/ext3/inode.c linux-2.6.11.new/fs/ext3/inode.c
--- linux-2.6.11/fs/ext3/inode.c	2005-03-01 23:38:13.000000000 -0800
+++ linux-2.6.11.new/fs/ext3/inode.c	2005-03-04 15:35:02.304473032 -0800
@@ -858,6 +858,12 @@ get_block:
 	return ret;
 }
 
+static int ext3_writepages_get_block(struct inode *inode, sector_t iblock,
+			struct buffer_head *bh, int create)
+{
+	return ext3_direct_io_get_blocks(inode, iblock, 1, bh, create);
+}
+
 /*
  * `handle' can be NULL if create is zero
  */
@@ -1323,6 +1329,45 @@ out_fail:
 	return ret;
 }
 
+static int 
+ext3_writeback_writepage_helper(struct page *page,
+				struct writeback_control *wbc)
+{
+	return block_write_full_page(page, ext3_get_block, wbc);
+}
+
+static int
+ext3_writeback_writepages(struct address_space *mapping, 
+				struct writeback_control *wbc)
+{
+	struct inode *inode = mapping->host;
+	handle_t *handle = NULL;
+	int err, ret = 0;
+
+	if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
+		return ret;
+
+	handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		return ret;
+	}
+
+        ret = __mpage_writepages(mapping, wbc, ext3_writepages_get_block,
+					ext3_writeback_writepage_helper);
+
+	/*
+	 * Need to reaquire the handle since ext3_writepages_get_block()
+	 * can restart the handle
+	 */
+	handle = journal_current_handle();
+
+	err = ext3_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
 static int ext3_writeback_writepage(struct page *page,
 				struct writeback_control *wbc)
 {
@@ -1554,6 +1599,7 @@ static struct address_space_operations e
 	.readpage	= ext3_readpage,
 	.readpages	= ext3_readpages,
 	.writepage	= ext3_writeback_writepage,
+	.writepages	= ext3_writeback_writepages,
 	.sync_page	= block_sync_page,
 	.prepare_write	= ext3_prepare_write,
 	.commit_write	= ext3_writeback_commit_write,
diff -Naurp -X dontdiff linux-2.6.11/fs/mpage.c linux-2.6.11.new/fs/mpage.c
--- linux-2.6.11/fs/mpage.c	2005-03-04 16:01:06.302709160 -0800
+++ linux-2.6.11.new/fs/mpage.c	2005-03-04 15:58:30.608378296 -0800
@@ -626,6 +626,15 @@ int
 mpage_writepages(struct address_space *mapping,
 		struct writeback_control *wbc, get_block_t get_block)
 {
+	return __mpage_writepages(mapping, wbc, get_block,
+		mapping->a_ops->writepage);
+}
+
+int
+__mpage_writepages(struct address_space *mapping,
+		struct writeback_control *wbc, get_block_t get_block,
+		writepage_t writepage_fn)
+{
 	struct backing_dev_info *bdi = mapping->backing_dev_info;
 	struct bio *bio = NULL;
 	sector_t last_block_in_bio = 0;
@@ -715,7 +724,7 @@ retry:
 			} else {
 				bio = __mpage_writepage(bio, page, get_block,
 						&last_block_in_bio, &ret, wbc,
-						page->mapping->a_ops->writepage);
+						writepage_fn);
 			}
 			if (ret || (--(wbc->nr_to_write) <= 0))
 				done = 1;
@@ -743,6 +752,7 @@ retry:
 	return ret;
 }
 EXPORT_SYMBOL(mpage_writepages);
+EXPORT_SYMBOL(__mpage_writepages);
 
 int mpage_writepage(struct page *page, get_block_t get_block,
 	struct writeback_control *wbc)
diff -Naurp -X dontdiff linux-2.6.11/include/linux/mpage.h linux-2.6.11.new/include/linux/mpage.h
--- linux-2.6.11/include/linux/mpage.h	2005-03-04 16:01:07.654503656 -0800
+++ linux-2.6.11.new/include/linux/mpage.h	2005-03-04 15:35:56.778191768 -0800
@@ -20,6 +20,9 @@ int mpage_writepages(struct address_spac
 		struct writeback_control *wbc, get_block_t get_block);
 int mpage_writepage(struct page *page, get_block_t *get_block,
 		struct writeback_control *wbc);
+int __mpage_writepages(struct address_space *mapping,
+		struct writeback_control *wbc, get_block_t get_block,
+		writepage_t writepage);
 
 static inline int
 generic_writepages(struct address_space *mapping, struct writeback_control *wbc)

Re: [PATCH] 2.6.11-mm1 ext3 writepages support for writeback mode

[Andrew Morton]

Badari Pulavarty <pbadari@us.ibm.com> wrote:
>
> Hi Andrew,
> 
> Here is the 2.6.11-mm1 patch for adding writepages support
> for ext3 writeback mode. Could you include it in -mm tree ?

spose so.  Does it work?

Do you have any benchmarking results handy?

> +static int
> +ext3_writeback_writepages(struct address_space *mapping, 
> +				struct writeback_control *wbc)
> +{
> +	struct inode *inode = mapping->host;
> +	handle_t *handle = NULL;
> +	int err, ret = 0;
> +
> +	if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
> +		return ret;

Can we please add a comment explaining why this is here?  I've already
forgotten why we put it there.

Re: [PATCH] 2.6.11-mm1 ext3 writepages support for writeback mode

[Badari Pulavarty]

On Fri, 2005-03-04 at 15:43, Andrew Morton wrote:
> Badari Pulavarty <pbadari@us.ibm.com> wrote:
> >
> > Hi Andrew,
> > 
> > Here is the 2.6.11-mm1 patch for adding writepages support
> > for ext3 writeback mode. Could you include it in -mm tree ?
> 
> spose so.  Does it work?
> 
> Do you have any benchmarking results handy?

I did few benchmarks earlier which showed 5-7% improvement
on throughput. I will run the numbers again.

> 
> > +static int
> > +ext3_writeback_writepages(struct address_space *mapping, 
> > +				struct writeback_control *wbc)
> > +{
> > +	struct inode *inode = mapping->host;
> > +	handle_t *handle = NULL;
> > +	int err, ret = 0;
> > +
> > +	if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
> > +		return ret;
> 
> Can we please add a comment explaining why this is here?  I've already
> forgotten why we put it there.

This is to avoid not starting the journal when we are trying to
destroy journal inode. I will add comments.

>       journal_destory()
>               iput(journal inode)
>                       do_writepages()
>                               generic_writepages()
>                                       ext3_writeback_writepage()
>                                               journal_start()

 
Thanks,
Badari