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commit a69d3d78fe39c602c351de7a2e8d65db271fbac0 Author: guohao15 <[email protected]> AuthorDate: Fri May 31 16:30:53 2024 +0800 inotify: add filter of notify options to reduce overload of system Signed-off-by: guohao15 <[email protected]> --- fs/notify/inotify.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 61 insertions(+), 4 deletions(-) diff --git a/fs/notify/inotify.c b/fs/notify/inotify.c index 74585c23b6..d621f42ebd 100644 --- a/fs/notify/inotify.c +++ b/fs/notify/inotify.c @@ -88,10 +88,12 @@ struct inotify_watch_s struct inotify_global_s { - mutex_t lock; /* Enforces global exclusive access */ - int event_cookie; /* Event cookie */ - int watch_cookie; /* Watch cookie */ - struct hsearch_data hash; /* Hash table for watch lists */ + mutex_t lock; /* Enforces global exclusive access */ + int event_cookie; /* Event cookie */ + int watch_cookie; /* Watch cookie */ + uint32_t read_count; /* Number of read events */ + uint32_t write_count; /* Number of write events */ + struct hsearch_data hash; /* Hash table for watch lists */ }; /**************************************************************************** @@ -145,6 +147,49 @@ static struct inotify_global_s g_inotify = * Private Functions ****************************************************************************/ +/**************************************************************************** + * Name: notify_add_count + * + * Description: + * Add the count. + * + ****************************************************************************/ + +static void inotify_add_count(uint32_t mask) +{ + g_inotify.read_count += (mask & IN_ACCESS) ? 1 : 0; + g_inotify.write_count += (mask & IN_MODIFY) ? 1 : 0; +} + +/**************************************************************************** + * Name: inotify_sub_count + * + * Description: + * Reduce the count. + * + ****************************************************************************/ + +static void inotify_sub_count(uint32_t mask) +{ + g_inotify.read_count -= (mask & IN_ACCESS) ? 1 : 0; + g_inotify.write_count -= (mask & IN_MODIFY) ? 1 : 0; +} + +/**************************************************************************** + * Name: notify_check_mask + * + * Description: + * Check if the count is valid. + * + ****************************************************************************/ + +static int notify_check_mask(uint32_t mask) +{ + return (((mask & IN_ACCESS) && g_inotify.read_count == 0) || + ((mask & IN_MODIFY) && g_inotify.write_count == 0)) ? + -EBADF : OK; +} + /**************************************************************************** * Name: inotify_alloc_event * @@ -262,6 +307,7 @@ inotify_remove_watch_no_event(FAR struct inotify_watch_s *watch) list_delete(&watch->d_node); list_delete(&watch->l_node); + inotify_sub_count(watch->mask); kmm_free(watch); if (list_is_empty(&list->watches)) @@ -931,6 +977,14 @@ static inline void notify_queue_filep_event(FAR struct file *filep, return; } + nxmutex_lock(&g_inotify.lock); + ret = notify_check_mask(mask); + nxmutex_unlock(&g_inotify.lock); + if (ret < 0) + { + return; + } + pathbuffer = lib_get_pathbuffer(); if (pathbuffer == NULL) { @@ -1037,6 +1091,7 @@ int inotify_add_watch(int fd, FAR const char *pathname, uint32_t mask) old = inotify_get_watch_from_list(dev, list); if (old != NULL) { + uint32_t tmpmask = old->mask; if (mask & IN_MASK_CREATE) { ret = -EEXIST; @@ -1052,6 +1107,7 @@ int inotify_add_watch(int fd, FAR const char *pathname, uint32_t mask) } ret = old->wd; + inotify_add_count(tmpmask ^ old->mask); } else { @@ -1066,6 +1122,7 @@ int inotify_add_watch(int fd, FAR const char *pathname, uint32_t mask) } ret = watch->wd; + inotify_add_count(mask); } out:
