From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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; _
