From 1f71ebedb3f8ce9108978168759c8551d873a912 Mon Sep 17 00:00:00 2001 From: Sukadev Bhattiprolu Date: Thu, 14 May 2009 19:38:24 -0700 Subject: [PATCH] devpts: correctly set default options devpts_get_sb() calls memset(0) to clear mount options and calls parse_mount_options() if user specified any mount options. The memset(0) is bogus since the 'mode' and 'ptmxmode' options are non-zero by default. parse_mount_options() restores options to default anyway and can properly deal with NULL mount options. So in devpts_get_sb() remove memset(0) and call parse_mount_options() even for NULL mount options. Bug reported by Eric Paris: http://lkml.org/lkml/2009/5/7/448. Signed-off-by: Sukadev Bhattiprolu Tested-by: Marc Dionne Reported-by: Eric Paris Cc: Christoph Hellwig Cc: Alan Cox Acked-by: Serge Hallyn Cc: Al Viro Cc: "Rafael J. Wysocki" Reviewed-by: "H. Peter Anvin" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/devpts/inode.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c index 21165cf934ff..c68edb969441 100644 --- a/fs/devpts/inode.c +++ b/fs/devpts/inode.c @@ -90,6 +90,15 @@ static inline struct super_block *pts_sb_from_inode(struct inode *inode) #define PARSE_MOUNT 0 #define PARSE_REMOUNT 1 +/* + * parse_mount_options(): + * Set @opts to mount options specified in @data. If an option is not + * specified in @data, set it to its default value. The exception is + * 'newinstance' option which can only be set/cleared on a mount (i.e. + * cannot be changed during remount). + * + * Note: @data may be NULL (in which case all options are set to default). + */ static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts) { char *p; @@ -355,12 +364,9 @@ static int devpts_get_sb(struct file_system_type *fs_type, struct pts_mount_opts opts; struct super_block *s; - memset(&opts, 0, sizeof(opts)); - if (data) { - error = parse_mount_options(data, PARSE_MOUNT, &opts); - if (error) - return error; - } + error = parse_mount_options(data, PARSE_MOUNT, &opts); + if (error) + return error; if (opts.newinstance) s = sget(fs_type, NULL, set_anon_super, NULL); -- 2.39.5