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Subject: [patch 013/158] mm/filemap.c: warn if stale pagecache is left after direct write
Date: Sat, 30 Nov 2019 17:49:47 -0800
Message-ID: <> (raw)

From: Konstantin Khlebnikov <>
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.

Signed-off-by: Konstantin Khlebnikov <>
Reviewed-by: Andrew Morton <>
Reviewed-by: Jan Kara <>
Cc: Jens Axboe <>
Cc: Alexander Viro <>
Signed-off-by: Andrew Morton <>

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

--- 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;

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