On Mon, Feb 04, 2019 at 03:20:05PM -0500, Dennis Zhou wrote: > -unsigned int btrfs_compress_str2level(const char *str) > +unsigned int btrfs_compress_str2level(unsigned int type, const char *str) > { > - if (strncmp(str, "zlib", 4) != 0) > + unsigned int level; > + int ret; > + > + if (!type) > return 0; > > - /* Accepted form: zlib:1 up to zlib:9 and nothing left after the number > */ > - if (str[4] == ':' && '1' <= str[5] && str[5] <= '9' && str[6] == 0) > - return str[5] - '0'; > + if (str[0] == ':') { > + ret = kstrtouint(str + 1, 10, &level);
The docs kstrtouint of say that initial + is also accepted, I'd rather keep the level specification strict, ie. no "zlib:+3" and no garbage after the number. The validation is currently missing but I think we should catch levels out of range during mount/remount. The fallback to default is a safety but wrong specification should be communicated to the user early.