ocfs2: fix snprintf() checking
The snprintf() function returns the number of bytes which would have been
printed if the buffer was large enough. In other words it can return ">=
remain" but this code assumes it returns "== remain".
The run time impact of this bug is not very severe. The next iteration
through the loop would trigger a WARN() when we pass a negative limit to
snprintf(). We would then return success instead of -E2BIG.
The kernel implementation of snprintf() will never return negatives so
there is no need to check and I have deleted that dead code.
Link: https://lkml.kernel.org/r/20210511135350.GV1955@kadam
Fixes: a860f6eb4c6a ("ocfs2: sysfile interfaces for online file check")
Fixes: 74ae4e104dfc ("ocfs2: Create stack glue sysfs files.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
index d50e8b8..16f1bfc 100644
--- a/fs/ocfs2/stackglue.c
+++ b/fs/ocfs2/stackglue.c
@@ -500,11 +500,7 @@ static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
ret = snprintf(buf, remain, "%s\n",
p->sp_name);
- if (ret < 0) {
- total = ret;
- break;
- }
- if (ret == remain) {
+ if (ret >= remain) {
/* snprintf() didn't fit */
total = -E2BIG;
break;
@@ -531,7 +527,7 @@ static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
if (active_stack) {
ret = snprintf(buf, PAGE_SIZE, "%s\n",
active_stack->sp_name);
- if (ret == PAGE_SIZE)
+ if (ret >= PAGE_SIZE)
ret = -E2BIG;
}
spin_unlock(&ocfs2_stack_lock);