| Message ID | 20210614211904.14420-2-hannes@cmpxchg.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/4] mm: remove irqsave/restore locking from contexts with irqs enabled | expand |
On Mon, Jun 14, 2021 at 05:19:02PM -0400, Johannes Weiner wrote: > 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. > > Reported-by: Roman Gushchin <guro@fb.com> > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Roman Gushchin <guro@fb.com> Thanks!
diff --git a/fs/drop_caches.c b/fs/drop_caches.c index f00fcc4a4f72..e619c31b6bd9 100644 --- a/fs/drop_caches.c +++ b/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 super_block *sb, void *unused) * 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; }
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. Reported-by: Roman Gushchin <guro@fb.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> --- fs/drop_caches.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)