Commit bb44c31c authored Sep 20, 2022 by Ronnie Sahlberg Committed by Steve French Sep 25, 2022

cifs: destage dirty pages before re-reading them for cache=none



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) <pc@cjr.nz>
Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

parent 09a1f9a1

fs/cifs/file.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -4271,6 +4271,15 @@ 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);