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fsnotify: Don't insert unmergeable events in hashtable

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Some events, like the overflow event, are not mergeable, so they are not
hashed.  But, when failing inside fsnotify_add_event for lack of space,
fsnotify_add_event() still calls the insert hook, which adds the
overflow event to the merge list.  Add a check to prevent any kind of
unmergeable event to be inserted in the hashtable.

Fixes: 94e00d28a680 ("fsnotify: use hash table for faster events merge")
Link: https://lore.kernel.org/r/20211025192746.66445-5-krisman@collabora.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Gabriel Krisman Bertazi 2021-10-25 16:27:19 -03:00 committed by Jan Kara
parent dabe729ddd
commit cc53b55f69
1 changed files with 4 additions and 2 deletions
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6
fs/notify/fanotify/fanotify.c
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@ -702,6 +702,9 @@ static void fanotify_insert_event(struct fsnotify_group *group,
assert_spin_locked(&group->notification_lock);
if (!fanotify_is_hashed_event(event->mask))
return;
pr_debug("%s: group=%p event=%p bucket=%u\n", __func__,
group, event, bucket);
@ -779,8 +782,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
fsn_event = &event->fse;
ret = fsnotify_add_event(group, fsn_event, fanotify_merge,
fanotify_is_hashed_event(mask) ?
fanotify_insert_event : NULL);
fanotify_insert_event);
if (ret) {
/* Permission events shouldn't be merged */
BUG_ON(ret == 1 && mask & FANOTIFY_PERM_EVENTS);