fanotify: Support enqueueing of error events

Once an error event is triggered, enqueue it in the notification group,
similarly to what is done for other events.  FAN_FS_ERROR is not
handled specially, since the memory is now handled by a preallocated
mempool.

For now, make the event unhashed.  A future patch implements merging of
this kind of event.

Link: https://lore.kernel.org/r/20211025192746.66445-21-krisman@collabora.com
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 01d68df..1f195c9 100644 (file)
--- 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_ONCE(!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 a577e87..ebef952 100644 (file)
--- 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));
 }