NFS: Allow the mount option retrans=0

We should allow retrans=0 as just meaning that every timeout is a major
timeout, and that there is no increment in the timeout value.

For instance, this means that we would allow TCP users to specify a
flat timeout value of 60s, by specifying "timeo=600,retrans=0" in their
mount option string.

Siged-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 17 insertions, 2 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 18d446e1a82b..d39601381adf 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -923,6 +923,8 @@ static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (data) {
+		data->timeo		= NFS_UNSPEC_TIMEO;
+		data->retrans		= NFS_UNSPEC_RETRANS;
 		data->acregmin		= NFS_DEF_ACREGMIN;
 		data->acregmax		= NFS_DEF_ACREGMAX;
 		data->acdirmin		= NFS_DEF_ACDIRMIN;
@@ -1189,6 +1191,19 @@ static int nfs_get_option_ul(substring_t args[], unsigned long *option)
 	return rc;
 }
 
+static int nfs_get_option_ul_bound(substring_t args[], unsigned long *option,
+		unsigned long l_bound, unsigned long u_bound)
+{
+	int ret;
+
+	ret = nfs_get_option_ul(args, option);
+	if (ret != 0)
+		return ret;
+	if (*option < l_bound || *option > u_bound)
+		return -ERANGE;
+	return 0;
+}
+
 /*
  * Error-check and convert a string of mount options from user space into
  * a data structure.  The whole mount string is processed; bad options are
@@ -1352,12 +1367,12 @@ static int nfs_parse_mount_options(char *raw,
 			mnt->bsize = option;
 			break;
 		case Opt_timeo:
-			if (nfs_get_option_ul(args, &option) || option == 0)
+			if (nfs_get_option_ul_bound(args, &option, 1, INT_MAX))
 				goto out_invalid_value;
 			mnt->timeo = option;
 			break;
 		case Opt_retrans:
-			if (nfs_get_option_ul(args, &option) || option == 0)
+			if (nfs_get_option_ul_bound(args, &option, 0, INT_MAX))
 				goto out_invalid_value;
 			mnt->retrans = option;
 			break;