mount options: fix devpts

Add a .show_options super operation to devpts.

Small cleanup: when parsing the "mode" option, mask with S_IALLUGO
instead of ~S_IFMT.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 3 deletions

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 06ef9a255c76..f120e1207874 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -20,9 +20,12 @@
 #include <linux/devpts_fs.h>
 #include <linux/parser.h>
 #include <linux/fsnotify.h>
+#include <linux/seq_file.h>
 
 #define DEVPTS_SUPER_MAGIC 0x1cd1
 
+#define DEVPTS_DEFAULT_MODE 0600
+
 static struct vfsmount *devpts_mnt;
 static struct dentry *devpts_root;
 
@@ -32,7 +35,7 @@ static struct {
         uid_t   uid;
         gid_t   gid;
         umode_t mode;
-} config = {.mode = 0600};
+} config = {.mode = DEVPTS_DEFAULT_MODE};
 
 enum {
         Opt_uid, Opt_gid, Opt_mode,
@@ -54,7 +57,7 @@ static int devpts_remount(struct super_block *sb, int *flags, char *data)
         config.setgid  = 0;
         config.uid     = 0;
         config.gid     = 0;
-        config.mode    = 0600;
+        config.mode    = DEVPTS_DEFAULT_MODE;
 
         while ((p = strsep(&data, ",")) != NULL) {
                 substring_t args[MAX_OPT_ARGS];
@@ -81,7 +84,7 @@ static int devpts_remount(struct super_block *sb, int *flags, char *data)
                 case Opt_mode:
                         if (match_octal(&args[0], &option))
                                 return -EINVAL;
-                        config.mode = option & ~S_IFMT;
+                        config.mode = option & S_IALLUGO;
                         break;
                 default:
                         printk(KERN_ERR "devpts: called with bogus options\n");
@@ -92,9 +95,21 @@ static int devpts_remount(struct super_block *sb, int *flags, char *data)
         return 0;
 }
 
+static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs)
+{
+        if (config.setuid)
+                seq_printf(seq, ",uid=%u", config.uid);
+        if (config.setgid)
+                seq_printf(seq, ",gid=%u", config.gid);
+        seq_printf(seq, ",mode=%03o", config.mode);
+
+        return 0;
+}
+
 static const struct super_operations devpts_sops = {
         .statfs         = simple_statfs,
         .remount_fs     = devpts_remount,
+        .show_options   = devpts_show_options,
 };
 
 static int