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[013/158] mm/filemap.c: warn if stale pagecache is left after direct write

Message ID 20191201014947.ru2upF2br%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [001/158] scripts/spelling.txt: add more spellings to spelling.txt | expand

Commit Message

Andrew Morton Dec. 1, 2019, 1:49 a.m. UTC
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Subject: mm/filemap.c: warn if stale pagecache is left after direct write

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>
---

 mm/filemap.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
diff mbox series

Patch

--- a/mm/filemap.c~fs-warn-if-stale-pagecache-is-left-after-direct-write
+++ a/mm/filemap.c
@@ -3241,11 +3241,13 @@  generic_file_direct_write(struct kiocb *
 	 * 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;