Commit 1f71ebed authored May 14, 2009 by Sukadev Bhattiprolu Committed by Linus Torvalds May 15, 2009

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 <sukadev@us.ibm.com>
Tested-by: Marc Dionne <marc.c.dionne@gmail.com>
Reported-by: Eric Paris <eparis@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Reviewed-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>

parent bd67ce0f

fs/devpts/inode.c

+12 −6

Original line number	Diff line number	Diff line
		@@ -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;
		}

		if (opts.newinstance)
		s = sget(fs_type, NULL, set_anon_super, NULL);

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