* Re: [PATCH] hostfs: Fix writeback of dirty pages
[not found] <20211105081052.2353801-1-sjoerd@collabora.com>
@ 2021-11-11 13:26 ` Christopher Obbard
0 siblings, 0 replies; only message in thread
From: Christopher Obbard @ 2021-11-11 13:26 UTC (permalink / raw)
To: Sjoerd Simons, linux-um
Cc: Anton Ivanov, Jeff Dike, Richard Weinberger, linux-kernel, stable
Hi Sjoerd,
On 05/11/2021 08:10, Sjoerd Simons wrote:
> Hostfs was not setting up the backing device information, which means it
> uses the noop bdi. The noop bdi does not have the writeback capability
> enabled, which in turns means dirty pages never got written back to
> storage.
>
> In other words programs using mmap to write to files on hostfs never
> actually got their data written out...
>
> Fix this by simply setting up the bdi with default settings as all the
> required code for writeback is already in place.
>
> Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
Cc: stable@vger.kernel.org
Reviewed-by: Christopher Obbard <chris.obbard@collabora.com>
...replying mainly as I wonder if adding the stable tag in a reply will
make the patch appear in stable (obviously once it is in mainline) ? :-)
>
> ---
>
> fs/hostfs/hostfs_kern.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
> index d5c9d886cd9f..ef481c3d9019 100644
> --- a/fs/hostfs/hostfs_kern.c
> +++ b/fs/hostfs/hostfs_kern.c
> @@ -924,6 +924,9 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
> sb->s_op = &hostfs_sbops;
> sb->s_d_op = &simple_dentry_operations;
> sb->s_maxbytes = MAX_LFS_FILESIZE;
> + err = super_setup_bdi(sb);
> + if (err)
> + goto out;
>
> /* NULL is printed as '(null)' by printf(): avoid that. */
> if (req_root == NULL)
>
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2021-11-11 13:26 ` [PATCH] hostfs: Fix writeback of dirty pages Christopher Obbard
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