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

Eric Sandeen
2008-06-18T18:23:41Z

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);
> + }

This seems fine.

I wonder, does it make any sense at all to only do the flushing if the
block we wish to map is actually in a delalloc state at the moment?

-Eric

> +
> if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
> /*
> * This is a REALLY heavyweight approach, but the use of