cifs: add warning about change in default cache semantics in 3.7

Add a warning that will be displayed when there is no cache= option
specified. We want to ensure that users are aware of the change in
defaults coming in 3.7.

Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 34186805e639..c49d49438c52 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1244,6 +1244,8 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
         char *string = NULL;
         char *tmp_end, *value;
         char delim;
+        bool cache_specified = false;
+        static bool cache_warned = false;
 
         separator[0] = ',';
         separator[1] = 0;
@@ -1455,6 +1457,7 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
                         vol->seal = 1;
                         break;
                 case Opt_direct:
+                        cache_specified = true;
                         vol->direct_io = true;
                         vol->strict_io = false;
                         cERROR(1, "The \"directio\" option will be removed in "
@@ -1462,6 +1465,7 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
                                   "option.");
                         break;
                 case Opt_strictcache:
+                        cache_specified = true;
                         vol->direct_io = false;
                         vol->strict_io = true;
                         cERROR(1, "The \"strictcache\" option will be removed "
@@ -1888,6 +1892,7 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
                                 goto cifs_parse_mount_err;
                         break;
                 case Opt_cache:
+                        cache_specified = true;
                         string = match_strdup(args);
                         if (string == NULL)
                                 goto out_nomem;
@@ -1938,6 +1943,14 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
                 printk(KERN_NOTICE "CIFS: ignoring forcegid mount option "
                                    "specified with no gid= option.\n");
 
+        /* FIXME: remove this block in 3.7 */
+        if (!cache_specified && !cache_warned) {
+                cache_warned = true;
+                printk(KERN_NOTICE "CIFS: no cache= option specified, using "
+                                   "\"cache=loose\". This default will change "
+                                   "to \"cache=strict\" in 3.7.\n");
+        }
+
         kfree(mountdata_copy);
         return 0;