On Fri, Oct 15, 2021 at 12:39 AM Gabriel Krisman Bertazi
<krisman@xxxxxxxxxxxxx> wrote:
>
> Error events (FAN_FS_ERROR) against the same file system can be merged
> by simply iterating the error count. The hash is taken from the fsid,
> without considering the FH. This means that only the first error object
> is reported.
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
> ---
> fs/notify/fanotify/fanotify.c | 39 ++++++++++++++++++++++++++++++++---
> fs/notify/fanotify/fanotify.h | 4 +++-
> 2 files changed, 39 insertions(+), 4 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> index 9b970359570a..7032083df62a 100644
> --- a/fs/notify/fanotify/fanotify.c
> +++ b/fs/notify/fanotify/fanotify.c
> @@ -111,6 +111,16 @@ static bool fanotify_name_event_equal(struct fanotify_name_event *fne1,
> return fanotify_info_equal(info1, info2);
> }
>
> +static bool fanotify_error_event_equal(struct fanotify_error_event *fee1,
> + struct fanotify_error_event *fee2)
> +{
> + /* Error events against the same file system are always merged. */
> + if (!fanotify_fsid_equal(&fee1->fsid, &fee2->fsid))
> + return false;
> +
> + return true;
> +}
> +
> static bool fanotify_should_merge(struct fanotify_event *old,
> struct fanotify_event *new)
> {
> @@ -141,6 +151,9 @@ static bool fanotify_should_merge(struct fanotify_event *old,
> case FANOTIFY_EVENT_TYPE_FID_NAME:
> return fanotify_name_event_equal(FANOTIFY_NE(old),
> FANOTIFY_NE(new));
> + case FANOTIFY_EVENT_TYPE_FS_ERROR:
> + return fanotify_error_event_equal(FANOTIFY_EE(old),
> + FANOTIFY_EE(new));
> default:
> WARN_ON_ONCE(1);
> }
> @@ -148,6 +161,22 @@ static bool fanotify_should_merge(struct fanotify_event *old,
> return false;
> }
>
> +static void fanotify_merge_error_event(struct fanotify_error_event *dest,
> + struct fanotify_error_event *origin)
> +{
> + dest->err_count++;
> +}
> +
> +static void fanotify_merge_event(struct fanotify_event *dest,
> + struct fanotify_event *origin)
> +{
> + dest->mask |= origin->mask;
> +
> + if (origin->type == FANOTIFY_EVENT_TYPE_FS_ERROR)
> + fanotify_merge_error_event(FANOTIFY_EE(dest),
> + FANOTIFY_EE(origin));
> +}
> +
> /* Limit event merges to limit CPU overhead per event */
> #define FANOTIFY_MAX_MERGE_EVENTS 128
>
> @@ -175,7 +204,7 @@ static int fanotify_merge(struct fsnotify_group *group,
> if (++i > FANOTIFY_MAX_MERGE_EVENTS)
> break;
> if (fanotify_should_merge(old, new)) {
> - old->mask |= new->mask;
> + fanotify_merge_event(old, new);
> return 1;
> }
> }
> @@ -577,7 +606,8 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *id,
> static struct fanotify_event *fanotify_alloc_error_event(
> struct fsnotify_group *group,
> __kernel_fsid_t *fsid,
> - const void *data, int data_type)
> + const void *data, int data_type,
> + unsigned int *hash)
> {
> struct fs_error_report *report =
> fsnotify_data_error_report(data, data_type);
> @@ -591,6 +621,9 @@ static struct fanotify_event *fanotify_alloc_error_event(
> return NULL;
>
> fee->fae.type = FANOTIFY_EVENT_TYPE_FS_ERROR;
> + fee->err_count = 1;
> +
> + *hash ^= fanotify_hash_fsid(fsid);
>
> return &fee->fae;
> }
Forgot to store fee->fsid?
Thanks,
Amir.
