linux-kernel - [PATCH AUTOSEL 5.17 20/21] Adjust cifssb maximum read size

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Message-Id: <20220328194157.1585642-20-sashal@kernel.org>
Date:   Mon, 28 Mar 2022 15:41:55 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Rohith Surabattula <rohiths@...rosoft.com>,
        Paulo Alcantara <pc@....nz>,
        Steve French <stfrench@...rosoft.com>,
        Sasha Levin <sashal@...nel.org>, sfrench@...ba.org,
        linux-cifs@...r.kernel.org, samba-technical@...ts.samba.org
Subject: [PATCH AUTOSEL 5.17 20/21] Adjust cifssb maximum read size

From: Rohith Surabattula <rohiths@...rosoft.com>

[ Upstream commit 06a466565d54a1a42168f9033a062a3f5c40e73b ]

When session gets reconnected during mount then read size in super block fs context
gets set to zero and after negotiate, rsize is not modified which results in
incorrect read with requested bytes as zero. Fixes intermittent failure
of xfstest generic/240

Note that stable requires a different version of this patch which will be
sent to the stable mailing list.

Signed-off-by: Rohith Surabattula <rohiths@...rosoft.com>
Acked-by: Paulo Alcantara (SUSE) <pc@....nz>
Signed-off-by: Steve French <stfrench@...rosoft.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/cifs/cifsfs.c |  3 +++
 fs/cifs/file.c   | 10 ++++++++++
 2 files changed, 13 insertions(+)

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 082c21478686..f89bb6e154f1 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -210,6 +210,9 @@ cifs_read_super(struct super_block *sb)
 	if (rc)
 		goto out_no_root;
 	/* tune readahead according to rsize if readahead size not set on mount */
+	if (cifs_sb->ctx->rsize == 0)
+		cifs_sb->ctx->rsize =
+			tcon->ses->server->ops->negotiate_rsize(tcon, cifs_sb->ctx);
 	if (cifs_sb->ctx->rasize)
 		sb->s_bdi->ra_pages = cifs_sb->ctx->rasize / PAGE_SIZE;
 	else
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index e7af802dcfa6..a2723f7cb5e9 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3740,6 +3740,11 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
 				break;
 		}
 
+		if (cifs_sb->ctx->rsize == 0)
+			cifs_sb->ctx->rsize =
+				server->ops->negotiate_rsize(tlink_tcon(open_file->tlink),
+							     cifs_sb->ctx);
+
 		rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->rsize,
 						   &rsize, credits);
 		if (rc)
@@ -4474,6 +4479,11 @@ static void cifs_readahead(struct readahead_control *ractl)
 			}
 		}
 
+		if (cifs_sb->ctx->rsize == 0)
+			cifs_sb->ctx->rsize =
+				server->ops->negotiate_rsize(tlink_tcon(open_file->tlink),
+							     cifs_sb->ctx);
+
 		rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->rsize,
 						   &rsize, credits);
 		if (rc)
-- 
2.34.1