From 0d814a2199cf226d6c48fe8523ae146bed820d08 Mon Sep 17 00:00:00 2001 From: Ronnie Sahlberg Date: Tue, 20 Sep 2022 14:32:02 +1000 Subject: [PATCH] cifs: destage dirty pages before re-reading them for cache=none commit bb44c31cdcac107344dd2fcc3bd0504a53575c51 upstream. This is the opposite case of kernel bugzilla 216301. If we mmap a file using cache=none and then proceed to update the mmapped area these updates are not reflected in a later pread() of that part of the file. To fix this we must first destage any dirty pages in the range before we allow the pread() to proceed. Cc: stable@vger.kernel.org Reviewed-by: Paulo Alcantara (SUSE) Reviewed-by: Enzo Matsumiya Signed-off-by: Ronnie Sahlberg Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/cifs/file.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 2ef57bc..ffec3a2 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -4015,6 +4015,15 @@ static ssize_t __cifs_readv( len = ctx->len; } + if (direct) { + rc = filemap_write_and_wait_range(file->f_inode->i_mapping, + offset, offset + len - 1); + if (rc) { + kref_put(&ctx->refcount, cifs_aio_ctx_release); + return -EAGAIN; + } + } + /* grab a lock here due to read response handlers can access ctx */ mutex_lock(&ctx->aio_mutex); -- 2.7.4