Re: [PATCH 05/11] cachefiles: Trace active-mark failure

[Jeff Layton <jlayton@kernel.org>]

On Tue, 2022-01-18 at 13:54 +0000, David Howells wrote:
> Add a tracepoint to log failure to apply an active mark to a file in
> addition to tracing successfully setting and unsetting the mark.
> 
> Also include the backing file inode number in the message logged to dmesg.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: linux-cachefs@redhat.com
> ---
> 
>  fs/cachefiles/namei.c             |    4 +++-
>  include/trace/events/cachefiles.h |   21 +++++++++++++++++++++
>  2 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
> index 52c9f0864a87..f256c8aff7bb 100644
> --- a/fs/cachefiles/namei.c
> +++ b/fs/cachefiles/namei.c
> @@ -25,7 +25,9 @@ static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object,
>  		trace_cachefiles_mark_active(object, inode);
>  		can_use = true;
>  	} else {
> -		pr_notice("cachefiles: Inode already in use: %pd\n", dentry);
> +		trace_cachefiles_mark_failed(object, inode);
> +		pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
> +			  dentry, inode->i_ino);
>  	}
>  
>  	return can_use;
> diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h
> index 093c4acb7a3a..c6f5aa74db89 100644
> --- a/include/trace/events/cachefiles.h
> +++ b/include/trace/events/cachefiles.h
> @@ -573,6 +573,27 @@ TRACE_EVENT(cachefiles_mark_active,
>  		      __entry->obj, __entry->inode)
>  	    );
>  
> +TRACE_EVENT(cachefiles_mark_failed,
> +	    TP_PROTO(struct cachefiles_object *obj,
> +		     struct inode *inode),
> +
> +	    TP_ARGS(obj, inode),
> +
> +	    /* Note that obj may be NULL */
> +	    TP_STRUCT__entry(
> +		    __field(unsigned int,		obj		)
> +		    __field(ino_t,			inode		)
> +			     ),
> +
> +	    TP_fast_assign(
> +		    __entry->obj	= obj ? obj->debug_id : 0;
> +		    __entry->inode	= inode->i_ino;
> +			   ),
> +
> +	    TP_printk("o=%08x B=%lx",
> +		      __entry->obj, __entry->inode)
> +	    );
> +
>  TRACE_EVENT(cachefiles_mark_inactive,
>  	    TP_PROTO(struct cachefiles_object *obj,
>  		     struct inode *inode),
> 
> 

Reviewed-by: Jeff Layton <jlayton@kernel.org>