From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Tue, 18 Jan 2022 12:16:57 +1000
Subject: [PATCH] cifs: serialize all mount attempts
Git-commit: 5455b9ecaf231ec5c6b0cd5c6076eb64c9dbc9aa
References: bsc#1193629
Patch-mainline: v5.17-rc1
RHBZ: 2008434
Some servers, such as Windows2016 have a very low number of concurrent mounts that
they allow from each client.
This can be a problem if you have a more than a handful (==3 in this case)
of cifs entries in your fstab and cause a number of the mounts there to randomly fail.
Add a global mutex and use it to serialize all mount attempts.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
fs/cifs/fs_context.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
index e3ed25dc6f3f..7ec35f3f0a5f 100644
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -37,6 +37,8 @@
#include "rfc1002pdu.h"
#include "fs_context.h"
+static DEFINE_MUTEX(cifs_mount_mutex);
+
static const match_table_t cifs_smb_version_tokens = {
{ Smb_1, SMB1_VERSION_STRING },
{ Smb_20, SMB20_VERSION_STRING},
@@ -707,10 +709,14 @@ static int smb3_get_tree_common(struct fs_context *fc)
static int smb3_get_tree(struct fs_context *fc)
{
int err = smb3_fs_context_validate(fc);
+ int ret;
if (err)
return err;
- return smb3_get_tree_common(fc);
+ mutex_lock(&cifs_mount_mutex);
+ ret = smb3_get_tree_common(fc);
+ mutex_unlock(&cifs_mount_mutex);
+ return ret;
}
static void smb3_fs_context_free(struct fs_context *fc)
--
2.36.1