f2fs: don't allow negative ->write_io_size_bits

As Dan reported:

"We put an upper bound on ->write_io_size_bits but we don't have a lower
bound."

So let's add lower bound check for ->write_io_size_bits in parse_options().

[We don't allow configuring ->write_io_size_bits to zero, since at least
we need to fill one dummy page for aligned IO.]

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index be8be445c6ed299f0464ea869302e57267818205..230845221c74cf513c9b274e69e39ba7c9a0c953 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -586,7 +586,7 @@ static int parse_options(struct super_block *sb, char *options)
                case Opt_io_size_bits:
                        if (args->from && match_int(args, &arg))
                                return -EINVAL;
-                       if (arg > __ilog2_u32(BIO_MAX_PAGES)) {
+                       if (arg <= 0 || arg > __ilog2_u32(BIO_MAX_PAGES)) {
                                f2fs_msg(sb, KERN_WARNING,
                                        "Not support %d, larger than %d",
                                        1 << arg, BIO_MAX_PAGES);