On 9/2/22 6:53 PM, Jia Zhu wrote:
> In erofs umount scenario, erofs_fscache_unregister_cookie() is called
> twice in kill_sb() and put_super().
>
> It works for original semantics, cause 'ctx' will be set to NULL in
> put_super() and will not be unregister again in kill_sb().
> However, in shared domain scenario, we use refcount to maintain the
> lifecycle of cookie. Unregister the cookie twice will cause it to be
> released early.
>
> For the above reasons, this patch removes duplicate unregister_cookie
> and move fscache_unregister_* before shotdown_super() to prevent busy
> inode(ctx->inode) when umount.
>
> Signed-off-by: Jia Zhu <zhujia.zj@xxxxxxxxxxxxx>
> ---
> fs/erofs/super.c | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 69de1731f454..667a78f0ee70 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -919,19 +919,20 @@ static void erofs_kill_sb(struct super_block *sb)
> kill_litter_super(sb);
> return;
> }
> - if (erofs_is_fscache_mode(sb))
> - generic_shutdown_super(sb);
> - else
> - kill_block_super(sb);
> -
> sbi = EROFS_SB(sb);
> if (!sbi)
> return;
>
> + if (erofs_is_fscache_mode(sb)) {
> + erofs_fscache_unregister_cookie(&sbi->s_fscache);
> + erofs_fscache_unregister_fs(sb);
> + generic_shutdown_super(sb);
Generally we can't do clean ups before generic_shutdown_super(), since
generic_shutdown_super() may trigger IO, e.g. in sync_filesystem(),
though it's not the case for erofs (read-only).
How about embedding erofs_fscache_unregister_cookie() into
erofs_fscache_unregister_fs(), and thus we can check domain_id in
erofs_fscache_unregister_fs()?
> + } else {
> + kill_block_super(sb);
> + }
> +
> erofs_free_dev_context(sbi->devs);
> fs_put_dax(sbi->dax_dev, NULL);
> - erofs_fscache_unregister_cookie(&sbi->s_fscache);
> - erofs_fscache_unregister_fs(sb);
> kfree(sbi->opt.fsid);
> kfree(sbi->opt.domain_id);
> kfree(sbi);
> @@ -951,7 +952,6 @@ static void erofs_put_super(struct super_block *sb)
> iput(sbi->managed_cache);
> sbi->managed_cache = NULL;
> #endif
> - erofs_fscache_unregister_cookie(&sbi->s_fscache);
> }
>
> struct file_system_type erofs_fs_type = {
--
Thanks,
Jingbo
