From: Johannes Weiner <hannes@xxxxxxxxxxx> Subject: fs: drop_caches: fix skipping over shadow cache inodes When drop_caches truncates the page cache in an inode it also includes any shadow entries for evicted pages. However, there is a preliminary check on whether the inode has pages: if it has *only* shadow entries, it will skip running truncation on the inode and leave it behind. Fix the check to mapping_empty(), such that it runs truncation on any inode that has cache entries at all. Link: https://lkml.kernel.org/r/20210614211904.14420-2-hannes@xxxxxxxxxxx Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> Reported-by: Roman Gushchin <guro@xxxxxx> Acked-by: Roman Gushchin <guro@xxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/drop_caches.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/drop_caches.c~fs-drop_caches-fix-skipping-over-shadow-cache-inodes +++ a/fs/drop_caches.c @@ -3,6 +3,7 @@ * Implement the manual drop-all-pagecache function */ +#include <linux/pagemap.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/fs.h> @@ -27,7 +28,7 @@ static void drop_pagecache_sb(struct sup * we need to reschedule to avoid softlockups. */ if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) || - (inode->i_mapping->nrpages == 0 && !need_resched())) { + (mapping_empty(inode->i_mapping) && !need_resched())) { spin_unlock(&inode->i_lock); continue; } _
