From 72fae6308a4e13036c7f1db79a1e4fd3d1a2f8aa Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Date: Sat, 30 Nov 2019 17:49:47 -0800
Subject: [PATCH] mm/filemap.c: warn if stale pagecache is left after direct
write
References: bnc#1155780 (VM/FS functional and performance backports)
Patch-mainline: v5.5-rc1
Git-commit: 9266a14033a81b3096feccd10542c20b3f47fe8e
generic_file_direct_write() tries to invalidate pagecache after O_DIRECT
write. Unlike to similar code in dio_complete() this silently ignores
error returned from invalidate_inode_pages2_range().
According to comment this code here because not all filesystems call
dio_complete() to do proper invalidation after O_DIRECT write. Noticeable
example is a blkdev_direct_IO().
This patch calls dio_warn_stale_pagecache() if invalidation fails.
Link: http://lkml.kernel.org/r/157270038294.4812.2238891109785106069.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/filemap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 00a058197293..15ca014f5581 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3246,11 +3246,13 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
* do not end up with dio_complete() being called, so let's not break
* them by removing it completely.
*
+ * Noticeable example is a blkdev_direct_IO().
+ *
* Skip invalidation for async writes or if mapping has no pages.
*/
- if (written > 0 && mapping->nrpages)
- invalidate_inode_pages2_range(mapping,
- pos >> PAGE_SHIFT, end);
+ if (written > 0 && mapping->nrpages &&
+ invalidate_inode_pages2_range(mapping, pos >> PAGE_SHIFT, end))
+ dio_warn_stale_pagecache(file);
if (written > 0) {
pos += written;