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

Aneesh Kumar K.V
2008-06-19T03:29:25Z

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@linux.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@linux.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@linux.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