linux-ext4 - Re: [PATCH v7 20/28] fanotify: Support enqueueing of error events

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Date:   Fri, 15 Oct 2021 14:34:40 +0200
From:   Jan Kara <jack@...e.cz>
To:     Gabriel Krisman Bertazi <krisman@...labora.com>
Cc:     jack@...e.com, amir73il@...il.com, djwong@...nel.org,
        tytso@....edu, dhowells@...hat.com, khazhy@...gle.com,
        linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org,
        linux-api@...r.kernel.org, repnop@...gle.com, kernel@...labora.com
Subject: Re: [PATCH v7 20/28] fanotify: Support enqueueing of error events

On Thu 14-10-21 18:36:38, Gabriel Krisman Bertazi wrote:
> Once an error event is triggered, collect the data from the fs error
> report and enqueue it in the notification group, similarly to what is
> done for other events.  FAN_FS_ERROR is no longer handled specially,
> since the memory is now handled by a preallocated mempool.
> 
> For now, make the event unhashed.  A future patch implements merging for
> these kinds of events.
> 
> Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza


> ---
>  fs/notify/fanotify/fanotify.c | 35 +++++++++++++++++++++++++++++++++++
>  fs/notify/fanotify/fanotify.h |  6 ++++++
>  2 files changed, 41 insertions(+)
> 
> diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> index 01d68dfc74aa..9b970359570a 100644
> --- a/fs/notify/fanotify/fanotify.c
> +++ b/fs/notify/fanotify/fanotify.c
> @@ -574,6 +574,27 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *id,
>  	return &fne->fae;
>  }
>  
> +static struct fanotify_event *fanotify_alloc_error_event(
> +						struct fsnotify_group *group,
> +						__kernel_fsid_t *fsid,
> +						const void *data, int data_type)
> +{
> +	struct fs_error_report *report =
> +			fsnotify_data_error_report(data, data_type);
> +	struct fanotify_error_event *fee;
> +
> +	if (WARN_ON(!report))
> +		return NULL;
> +
> +	fee = mempool_alloc(&group->fanotify_data.error_events_pool, GFP_NOFS);
> +	if (!fee)
> +		return NULL;
> +
> +	fee->fae.type = FANOTIFY_EVENT_TYPE_FS_ERROR;
> +
> +	return &fee->fae;
> +}
> +
>  static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
>  						   u32 mask, const void *data,
>  						   int data_type, struct inode *dir,
> @@ -641,6 +662,9 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
>  
>  	if (fanotify_is_perm_event(mask)) {
>  		event = fanotify_alloc_perm_event(path, gfp);
> +	} else if (fanotify_is_error_event(mask)) {
> +		event = fanotify_alloc_error_event(group, fsid, data,
> +						   data_type);
>  	} else if (name_event && (file_name || child)) {
>  		event = fanotify_alloc_name_event(id, fsid, file_name, child,
>  						  &hash, gfp);
> @@ -850,6 +874,14 @@ static void fanotify_free_name_event(struct fanotify_event *event)
>  	kfree(FANOTIFY_NE(event));
>  }
>  
> +static void fanotify_free_error_event(struct fsnotify_group *group,
> +				      struct fanotify_event *event)
> +{
> +	struct fanotify_error_event *fee = FANOTIFY_EE(event);
> +
> +	mempool_free(fee, &group->fanotify_data.error_events_pool);
> +}
> +
>  static void fanotify_free_event(struct fsnotify_group *group,
>  				struct fsnotify_event *fsn_event)
>  {
> @@ -873,6 +905,9 @@ static void fanotify_free_event(struct fsnotify_group *group,
>  	case FANOTIFY_EVENT_TYPE_OVERFLOW:
>  		kfree(event);
>  		break;
> +	case FANOTIFY_EVENT_TYPE_FS_ERROR:
> +		fanotify_free_error_event(group, event);
> +		break;
>  	default:
>  		WARN_ON_ONCE(1);
>  	}
> diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
> index a577e87fac2b..ebef952481fa 100644
> --- a/fs/notify/fanotify/fanotify.h
> +++ b/fs/notify/fanotify/fanotify.h
> @@ -298,6 +298,11 @@ static inline struct fanotify_event *FANOTIFY_E(struct fsnotify_event *fse)
>  	return container_of(fse, struct fanotify_event, fse);
>  }
>  
> +static inline bool fanotify_is_error_event(u32 mask)
> +{
> +	return mask & FAN_FS_ERROR;
> +}
> +
>  static inline bool fanotify_event_has_path(struct fanotify_event *event)
>  {
>  	return event->type == FANOTIFY_EVENT_TYPE_PATH ||
> @@ -327,6 +332,7 @@ static inline struct path *fanotify_event_path(struct fanotify_event *event)
>  static inline bool fanotify_is_hashed_event(u32 mask)
>  {
>  	return !(fanotify_is_perm_event(mask) ||
> +		 fanotify_is_error_event(mask) ||
>  		 fsnotify_is_overflow_event(mask));
>  }
>  
> -- 
> 2.33.0
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR