[Devel] [PATCH 1/2] fuse kio: Do not try to populate fuse_inode::private on second open

[Pavel Butsykin]

On 11.10.2018 18:00, Kirill Tkhai wrote:
> Introduce flag to mark files served by userspace.
> It helps kio to understand it's not needed to send
> a request to userspace, when private is NULL.
> Introducing some special value to encode inodes,
> served in userspace, (for example ~0UL), does not
> look better, since it makes !fi->private checks
> more difficult (also we have a lot free bits
> in inode flags).
> 
> Synchronization is "caller owns inode->i_mutex".
> 
> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>

Reviewed-by: Pavel Butsykin <pbutsykin at virtuozzo.com>

> ---
>   fs/fuse/fuse_i.h                   |    3 +++
>   fs/fuse/kio/pcs/pcs_fuse_kdirect.c |   11 +++++++++--
>   2 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
> index 69dfd0c318fe..d7dd571c08f6 100644
> --- a/fs/fuse/fuse_i.h
> +++ b/fs/fuse/fuse_i.h
> @@ -147,6 +147,9 @@ enum {
>   	FUSE_I_SIZE_UNSTABLE,
>   	/** i_mtime has been updated locally; a flush to userspace needed */
>   	FUSE_I_MTIME_UPDATED,
> +
> +	/** kdirect open try has already made */
> +	FUSE_I_KIO_OPEN_TRY_MADE,
>   };
>   
>   struct fuse_conn;
> diff --git a/fs/fuse/kio/pcs/pcs_fuse_kdirect.c b/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
> index 14bed318d139..f221001519c3 100644
> --- a/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
> +++ b/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
> @@ -359,7 +359,7 @@ int kpcs_file_open(struct fuse_conn *fc, struct file *file, struct inode *inode)
>   	struct fuse_inode *fi = get_fuse_inode(inode);
>   	struct pcs_dentry_info *di = fi->private;
>   	struct pcs_mds_fileinfo info;
> -	int ret;
> +	int ret = 0;
>   
>   	if (!S_ISREG(inode->i_mode))
>   		return 0;
> @@ -378,7 +378,14 @@ int kpcs_file_open(struct fuse_conn *fc, struct file *file, struct inode *inode)
>   		spin_unlock(&di->lock);
>   		return 0;
>   	}
> -	return kpcs_do_file_open(fc, file, inode);
> +
> +	if (!test_bit(FUSE_I_KIO_OPEN_TRY_MADE, &fi->state)) {
> +		ret = kpcs_do_file_open(fc, file, inode);
> +		if (!ret)
> +			set_bit(FUSE_I_KIO_OPEN_TRY_MADE, &fi->state);
> +	}
> +
> +	return ret;
>   }
>   
>   void kpcs_inode_release(struct fuse_inode *fi)
>