cifs: new mount option called retrans

We have several places in the code where we treat the
error -EAGAIN very differently. Some code retry for
arbitrary number of times.

Introducing this new mount option named "retrans", so
that all these handlers of -EAGAIN can retry a fixed
number of times. This applies only to soft mounts.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/client/cifsfs.c

@@ -681,6 +681,8 @@ cifs_show_options(struct seq_file *s, struct dentry *root)
 		seq_printf(s, ",rasize=%u", cifs_sb->ctx->rasize);
 	if (tcon->ses->server->min_offload)
 		seq_printf(s, ",esize=%u", tcon->ses->server->min_offload);
+	if (tcon->ses->server->retrans)
+		seq_printf(s, ",retrans=%u", tcon->ses->server->retrans);
 	seq_printf(s, ",echo_interval=%lu",
 			tcon->ses->server->echo_interval / HZ);
 

fs/smb/client/cifsglob.h

@@ -753,6 +753,7 @@ struct TCP_Server_Info {
 	unsigned int	max_read;
 	unsigned int	max_write;
 	unsigned int	min_offload;
+	unsigned int	retrans;
 	__le16	compress_algorithm;
 	__u16	signing_algorithm;
 	__le16	cipher_type;

fs/smb/client/connect.c

@@ -1574,6 +1574,9 @@ static int match_server(struct TCP_Server_Info *server,
 	if (server->min_offload != ctx->min_offload)
 		return 0;
 
+	if (server->retrans != ctx->retrans)
+		return 0;
+
 	return 1;
 }
 
@@ -1798,6 +1801,7 @@ cifs_get_tcp_session(struct smb3_fs_context *ctx,
 		goto out_err_crypto_release;
 	}
 	tcp_ses->min_offload = ctx->min_offload;
+	tcp_ses->retrans = ctx->retrans;
 	/*
 	 * at this point we are the only ones with the pointer
 	 * to the struct since the kernel thread not created yet

fs/smb/client/fs_context.c

@@ -139,6 +139,7 @@ const struct fs_parameter_spec smb3_fs_parameters[] = {
 	fsparam_u32("dir_mode", Opt_dirmode),
 	fsparam_u32("port", Opt_port),
 	fsparam_u32("min_enc_offload", Opt_min_enc_offload),
+	fsparam_u32("retrans", Opt_retrans),
 	fsparam_u32("esize", Opt_min_enc_offload),
 	fsparam_u32("bsize", Opt_blocksize),
 	fsparam_u32("rasize", Opt_rasize),
@@ -1064,6 +1065,9 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
 	case Opt_min_enc_offload:
 		ctx->min_offload = result.uint_32;
 		break;
+	case Opt_retrans:
+		ctx->retrans = result.uint_32;
+		break;
 	case Opt_blocksize:
 		/*
 		 * inode blocksize realistically should never need to be
@@ -1619,6 +1623,8 @@ int smb3_init_fs_context(struct fs_context *fc)
 	ctx->backupuid_specified = false; /* no backup intent for a user */
 	ctx->backupgid_specified = false; /* no backup intent for a group */
 
+	ctx->retrans = 1;
+
 /*
  *	short int override_uid = -1;
  *	short int override_gid = -1;

fs/smb/client/fs_context.h

@@ -118,6 +118,7 @@ enum cifs_param {
 	Opt_file_mode,
 	Opt_dirmode,
 	Opt_min_enc_offload,
+	Opt_retrans,
 	Opt_blocksize,
 	Opt_rasize,
 	Opt_rsize,
@@ -245,6 +246,7 @@ struct smb3_fs_context {
 	unsigned int rsize;
 	unsigned int wsize;
 	unsigned int min_offload;
+	unsigned int retrans;
 	bool sockopt_tcp_nodelay:1;
 	/* attribute cache timemout for files and directories in jiffies */
 	unsigned long acregmax;