linux-ext4 - Re: BUG with delayed allocation

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Date:	Thu, 20 Mar 2008 00:02:55 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	Mingming Cao <cmm@...ibm.com>, ext4 <linux-ext4@...r.kernel.org>
Subject: Re: BUG with delayed allocation

On Wed, Mar 19, 2008 at 09:42:13AM -0500, Eric Sandeen wrote:
> Aneesh Kumar K.V wrote:
> > Hi,
> > 
> > Eric actually observed it yesterday. I am able to reproduce it locally.
> > With delayed allocation we are observing wrong value of i_size.
> > 
> > kenrel: 2.6.25-rc5 +
> > With all the patches in the patch queue
> 
> ...
> 
> I also see this with only:
> 
> patches/delalloc-vfs.patch
> patches/delalloc-ext4.patch
> 
> applied.

This one seems to work for me. Need to think a bit more about parallel
truncate.

-aneesh

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 79930df..b74426d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1488,6 +1488,43 @@ out:
 
 	return ret;
 }
+static int ext4_da_writepage(struct page *page,
+				struct writeback_control *wbc)
+{
+	struct inode *inode = page->mapping->host;
+	handle_t *handle = NULL;
+	int ret = 0;
+	int err;
+
+	if (ext4_journal_current_handle())
+		goto out_fail;
+
+	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out_fail;
+	}
+
+	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
+		ret = nobh_writepage(page, ext4_get_block, wbc);
+	else
+		ret = block_write_full_page(page, ext4_get_block, wbc);
+
+	if (!ret && inode->i_size > EXT4_I(inode)->i_disksize) {
+		EXT4_I(inode)->i_disksize = inode->i_size;
+		ext4_mark_inode_dirty(handle, inode);
+	}
+
+	err = ext4_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+
+out_fail:
+	redirty_page_for_writepage(wbc, page);
+	unlock_page(page);
+	return ret;
+}
 
 static int ext4_da_writepages(struct address_space *mapping,
 				struct writeback_control *wbc)
@@ -2015,7 +2052,7 @@ static const struct address_space_operations ext4_journalled_aops = {
 static const struct address_space_operations ext4_da_aops = {
 	.readpage	= ext4_readpage,
 	.readpages	= ext4_readpages,
-	.writepage	= ext4_writeback_writepage,
+	.writepage	= ext4_da_writepage,
 	.writepages	= ext4_da_writepages,
 	.sync_page	= block_sync_page,
 	.write_begin	= ext4_da_write_begin,
--
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