isofs: Do not return EACCES for unknown filesystems

When isofs_mount() is called to mount a device read-write, it returns
EACCES even before it checks that the device actually contains an isofs
filesystem. This may confuse mount(8) which then tries to mount all
subsequent filesystem types in read-only mode.

Fix the problem by returning EACCES only once we verify that the device
indeed contains an iso9660 filesystem.

CC: stable@vger.kernel.org
Fixes: 17b7f7cf58
Reported-by: Kent Overstreet <kent.overstreet@gmail.com>
Reported-by: Karel Zak <kzak@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2016-10-04 13:44:06 +02:00
parent 1573d2caf7
commit a2ed0b391d

View File

@ -687,6 +687,11 @@ static int isofs_fill_super(struct super_block *s, void *data, int silent)
pri_bh = NULL;
root_found:
/* We don't support read-write mounts */
if (!(s->s_flags & MS_RDONLY)) {
error = -EACCES;
goto out_freebh;
}
if (joliet_level && (pri == NULL || !opt.rock)) {
/* This is the case of Joliet with the norock mount flag.
@ -1501,9 +1506,6 @@ struct inode *__isofs_iget(struct super_block *sb,
static struct dentry *isofs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
/* We don't support read-write mounts */
if (!(flags & MS_RDONLY))
return ERR_PTR(-EACCES);
return mount_bdev(fs_type, flags, dev_name, data, isofs_fill_super);
}