f2fs: add NULL pointer check
Commit - fa9150a84c - replaces a call to generic_writepages() in
f2fs_write_data_pages() with write_cache_pages(), with a function pointer
argument pointing to routine: __f2fs_writepage.
-> https://git.kernel.org/linus/fa9150a84ca333f68127097c4fa1eda4b3913a22
This patch adds a NULL pointer check in f2fs_write_data_pages() to avoid
a possible NULL pointer dereference, in case if - mapping->a_ops->writepage -
is NULL.
Signed-off-by: P J P <ppandit@redhat.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 47a2d7c..cf9ff5f 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -559,6 +559,10 @@
int ret;
long excess_nrtw = 0, desired_nrtw;
+ /* deal with chardevs and other special file */
+ if (!mapping->a_ops->writepage)
+ return 0;
+
if (wbc->nr_to_write < MAX_DESIRED_PAGES_WP) {
desired_nrtw = MAX_DESIRED_PAGES_WP;
excess_nrtw = desired_nrtw - wbc->nr_to_write;