Re: [PATCH 2/2] ext4: Fix mmap data corruption when blocksize < pagesize

Jan Kara
2014-09-24T08:45:26Z

On Tue 23-09-14 17:03:23, Jan Kara wrote:
> Use block_create_hole() when hole is being created in a file so that
> ->page_mkwrite() will get called for the partial tail page if it is
> mmaped (see the first patch in the series for details).
Just out of curiosity I did a change similar to this one for ext4 to XFS
and indeed it fixed generic/030 test failures for XFS with blocksize 1k.

Honza

PS: I forgot to CC xfs list in the original posting. You can find the VFS
patch e.g. at http://www.spinics.net/lists/linux-mm/msg78976.html

> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
> fs/ext4/inode.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 3aa26e9117c4..fdcb007c2c9e 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4536,8 +4536,12 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
> ext4_orphan_del(NULL, inode);
> goto err_out;
> }
> - } else
> + } else {
> + loff_t old_size = inode->i_size;
> +
> i_size_write(inode, attr->ia_size);
> + block_create_hole(inode, old_size, inode->i_size);
> + }
>
> /*
> * Blocks are going to be removed from the inode. Wait
> --
> 1.8.1.4
>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR