linux-ext4 - Re: [PATCH] ext4: Fix ext4_bmap to flush the data to the disk with delalloc

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Message-ID: <20080619032916.GA7250@skywalker>
Date:	Thu, 19 Jun 2008 08:59:16 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	Mingming <cmm@...ibm.com>
Cc:	tytso@....edu, sandeen@...hat.com, adilger@....com,
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH] ext4: Fix ext4_bmap to flush the data to the disk with
	delalloc

On Wed, Jun 18, 2008 at 03:26:25PM -0700, Mingming wrote:
> 
> On Wed, 2008-06-18 at 23:22 +0530, Aneesh Kumar K.V wrote:
> > With delalloc we don't do block allocation in the write_begin/write_end.
> > So when using bmap we first need to flush data to the disk so that blocks
> > get allocated and then call generic_block_bmap.
> > 
> > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
> > ---
> >  fs/ext4/inode.c |   11 +++++++++++
> >  1 files changed, 11 insertions(+), 0 deletions(-)
> > 
> > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> > index 7035621..cfeb869 100644
> > --- a/fs/ext4/inode.c
> > +++ b/fs/ext4/inode.c
> > @@ -1833,6 +1833,17 @@ sector_t ext4_bmap(struct address_space *mapping, sector_t block)
> >  	journal_t *journal;
> >  	int err;
> > 
> > +	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
> > +			test_opt(inode->i_sb, DELALLOC)) {
> > +		/*
> > +		 * With delalloc we want to sync the file
> > +		 * so that we can make sure we allocate
> > +		 * blocks for file
> > +		 */
> > +		filemap_fdatawrite(mapping);
> > +		filemap_fdatawait(mapping);
> > +	}
> > +
> 
> I would use filemap_write_and_wait(), it is essentially the same as
> above two functions, but with a little extra checking.
> 

Updated patch below

ext4: Fix ext4_bmap to flush the data to the disk with delalloc

From: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>

With delalloc we don't do block allocation in the write_begin/write_end.
So when using bmap we first need to flush data to the disk so that blocks
get allocated and then call generic_block_bmap.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---

 fs/ext4/inode.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)


diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 7035621..f1bd194 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1833,6 +1833,16 @@ sector_t ext4_bmap(struct address_space *mapping, sector_t block)
 	journal_t *journal;
 	int err;
 
+	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
+			test_opt(inode->i_sb, DELALLOC)) {
+		/*
+		 * With delalloc we want to sync the file
+		 * so that we can make sure we allocate
+		 * blocks for file
+		 */
+		filemap_write_and_wait(mapping);
+	}
+
 	if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
 		/*
 		 * This is a REALLY heavyweight approach, but the use of
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