Since FAN_FS_ERROR memory must be pre-allocated, limit a single group
from watching too many file systems at once. The current scheme
guarantees 1 slot per filesystem, so limit the number of marks with
FAN_FS_ERROR per group.
Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
---
fs/notify/fanotify/fanotify_user.c | 10 ++++++++++
include/linux/fsnotify_backend.h | 1 +
2 files changed, 11 insertions(+)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index f1cf863d6f9f..5324890500fc 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -959,6 +959,10 @@ static int fanotify_remove_mark(struct fsnotify_group *group,
removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags,
umask, &destroy_mark);
+
+ if (removed & FAN_FS_ERROR)
+ group->fanotify_data.error_event_marks--;
+
if (removed & fsnotify_conn_mask(fsn_mark->connector))
fsnotify_recalc_mask(fsn_mark->connector);
if (destroy_mark)
@@ -1057,6 +1061,9 @@ static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
static int fanotify_group_init_error_pool(struct fsnotify_group *group)
{
+ if (group->fanotify_data.error_event_marks >= FANOTIFY_DEFAULT_FEE_POOL)
+ return -ENOMEM;
+
if (mempool_initialized(&group->fanotify_data.error_events_pool))
return 0;
@@ -1098,6 +1105,9 @@ static int fanotify_add_mark(struct fsnotify_group *group,
if (added & ~fsnotify_conn_mask(fsn_mark->connector))
fsnotify_recalc_mask(fsn_mark->connector);
+ if (!(flags & FAN_MARK_IGNORED_MASK) && (mask & FAN_FS_ERROR))
+ group->fanotify_data.error_event_marks++;
+
out:
mutex_unlock(&group->mark_mutex);
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 9941c06b8c8a..96e1d31394ce 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -247,6 +247,7 @@ struct fsnotify_group {
int f_flags; /* event_f_flags from fanotify_init() */
struct ucounts *ucounts;
mempool_t error_events_pool;
+ unsigned int error_event_marks;
} fanotify_data;
#endif /* CONFIG_FANOTIFY */
};
--
2.33.0
