From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B25DC43603 for ; Tue, 17 Dec 2019 18:31:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 525CE2072D for ; Tue, 17 Dec 2019 18:31:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727940AbfLQSbp (ORCPT ); Tue, 17 Dec 2019 13:31:45 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:48912 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727005AbfLQSbp (ORCPT ); Tue, 17 Dec 2019 13:31:45 -0500 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1ihHdH-0002ou-80; Tue, 17 Dec 2019 18:31:43 +0000 Date: Tue, 17 Dec 2019 18:31:43 +0000 From: Al Viro To: Miklos Szeredi Cc: linux-fsdevel@vger.kernel.org, David Howells Subject: Re: [PATCH 09/12] fs_parser: "string" with missing value is a "flag" Message-ID: <20191217183143.GC4203@ZenIV.linux.org.uk> References: <20191128155940.17530-1-mszeredi@redhat.com> <20191128155940.17530-10-mszeredi@redhat.com> <20191217173259.GA4203@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191217173259.GA4203@ZenIV.linux.org.uk> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Dec 17, 2019 at 05:32:59PM +0000, Al Viro wrote: > No. This is simply wrong - as it is, there's no difference between > "foo" and "foo=". Passing NULL in the latter case is wrong, but > this is not a good fix. > > This > if (v_size > 0) { > param.string = kmemdup_nul(value, v_size, GFP_KERNEL); > if (!param.string) > return -ENOMEM; > } > should really be > if (value) { > param.string = kmemdup_nul(value, v_size, GFP_KERNEL); > if (!param.string) > return -ENOMEM; > } > and your chunk should be conditional upon value, not v_size. The > same problem exists for rbd.c How about this (completely untested): Pass consistent param->type to fs_parse() As it is, vfs_parse_fs_string() makes "foo" and "foo=" indistinguishable; both get fs_value_is_string for ->type and NULL for ->string. To make it even more unpleasant, that combination is impossible to produce with fsconfig(). Much saner rules would be "foo" => fs_value_is_flag, NULL "foo=" => fs_value_is_string, "" "foo=bar" => fs_value_is_string, "bar" All cases are distinguishable, all results are expressable by fsconfig(), ->has_value checks are much simpler that way (to the point of the field being useless) and quite a few regressions go away (gfs2 has no business accepting -o nodebug=, for example). Partially based upon patches from Miklos. Signed-off-by: Al Viro --- diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 2b184563cd32..9fc686be81ca 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -6433,7 +6433,7 @@ static int rbd_parse_options(char *options, struct rbd_parse_opts_ctx *pctx) if (*key) { struct fs_parameter param = { .key = key, - .type = fs_value_is_string, + .type = fs_value_is_flag, }; char *value = strchr(key, '='); size_t v_len = 0; @@ -6443,14 +6443,11 @@ static int rbd_parse_options(char *options, struct rbd_parse_opts_ctx *pctx) continue; *value++ = 0; v_len = strlen(value); - } - - - if (v_len > 0) { param.string = kmemdup_nul(value, v_len, GFP_KERNEL); if (!param.string) return -ENOMEM; + param.type = fs_value_is_string; } param.size = v_len; diff --git a/fs/fs_context.c b/fs/fs_context.c index 138b5b4d621d..9097421cbba5 100644 --- a/fs/fs_context.c +++ b/fs/fs_context.c @@ -175,14 +175,15 @@ int vfs_parse_fs_string(struct fs_context *fc, const char *key, struct fs_parameter param = { .key = key, - .type = fs_value_is_string, + .type = fs_value_is_flag, .size = v_size, }; - if (v_size > 0) { + if (value) { param.string = kmemdup_nul(value, v_size, GFP_KERNEL); if (!param.string) return -ENOMEM; + param.type = fs_value_is_string; } ret = vfs_parse_fs_param(fc, ¶m); diff --git a/fs/fs_parser.c b/fs/fs_parser.c index d1930adce68d..65842cd2e320 100644 --- a/fs/fs_parser.c +++ b/fs/fs_parser.c @@ -85,7 +85,6 @@ int fs_parse(struct fs_context *fc, const struct fs_parameter_enum *e; int ret = -ENOPARAM, b; - result->has_value = !!param->string; result->negated = false; result->uint_64 = 0; @@ -95,7 +94,7 @@ int fs_parse(struct fs_context *fc, * "xxx" takes the "no"-form negative - but only if there * wasn't an value. */ - if (result->has_value) + if (param->type != fs_value_is_flag) goto unknown_parameter; if (param->key[0] != 'n' || param->key[1] != 'o' || !param->key[2]) goto unknown_parameter; @@ -127,14 +126,13 @@ int fs_parse(struct fs_context *fc, case fs_param_is_u64: case fs_param_is_enum: case fs_param_is_string: - if (param->type != fs_value_is_string) - goto bad_value; - if (!result->has_value) { + if (param->type == fs_value_is_string) + break; + if (param->type == fs_value_is_flag) { if (p->flags & fs_param_v_optional) goto okay; - goto bad_value; } - /* Fall through */ + goto bad_value; default: break; } @@ -144,8 +142,7 @@ int fs_parse(struct fs_context *fc, */ switch (p->type) { case fs_param_is_flag: - if (param->type != fs_value_is_flag && - (param->type != fs_value_is_string || result->has_value)) + if (param->type != fs_value_is_flag) return invalf(fc, "%s: Unexpected value for '%s'", desc->name, param->key); result->boolean = true; @@ -206,9 +203,6 @@ int fs_parse(struct fs_context *fc, case fs_param_is_fd: { switch (param->type) { case fs_value_is_string: - if (!result->has_value) - goto bad_value; - ret = kstrtouint(param->string, 0, &result->uint_32); break; case fs_value_is_file: diff --git a/include/linux/fs_parser.h b/include/linux/fs_parser.h index dee140db6240..45323203128b 100644 --- a/include/linux/fs_parser.h +++ b/include/linux/fs_parser.h @@ -72,7 +72,6 @@ struct fs_parameter_description { */ struct fs_parse_result { bool negated; /* T if param was "noxxx" */ - bool has_value; /* T if value supplied to param */ union { bool boolean; /* For spec_bool */ int int_32; /* For spec_s32/spec_enum */