Commit 9266a140 authored Nov 30, 2019 by Konstantin Khlebnikov Committed by Linus Torvalds Dec 01, 2019

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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent a92853b6

mm/filemap.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -3241,11 +3241,13 @@ 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;

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