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Mon, 7 Oct 2019 11:36:19 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 66477AC19; Mon, 7 Oct 2019 15:36:16 +0000 (UTC) Subject: Re: [PATCH 3/4] btrfs: sysfs: export supported checksums To: Johannes Thumshirn , David Sterba Cc: Linux BTRFS Mailinglist References: <20191007091104.18095-1-jthumshirn@suse.de> <20191007091104.18095-4-jthumshirn@suse.de> From: Nikolay Borisov Openpgp: preference=signencrypt Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= mQINBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/nSSP8YgfwoOqwrP+JR4pIqRK0AWWeWCSwmZ T7g+RbfPFlmQp+EwFWOtABXlKC54zgSf+uulGwx5JAUFVUIRBmnHOYi/lUiE0yhpnb1KCA7f u/W+DkwGerXqhhe9TvQoGwgCKNfzFPZoM+gZrm+kWv03QLUCr210n4cwaCPJ0Nr9Z3c582xc bCUVbsjt7BN0CFa2BByulrx5xD9sDAYIqfLCcZetAqsTRGxM7LD0kh5WlKzOeAXj5r8DOrU2 GdZS33uKZI/kZJZVytSmZpswDsKhnGzRN1BANGP8sC+WD4eRXajOmNh2HL4P+meO1TlM3GLl EQd2shHFY0qjEo7wxKZI1RyZZ5AgJnSmehrPCyuIyVY210CbMaIKHUIsTqRgY5GaNME24w7h TyyVCy2qAM8fLJ4Vw5bycM/u5xfWm7gyTb9V1TkZ3o1MTrEsrcqFiRrBY94Rs0oQkZvunqia c+NprYSaOG1Cta14o94eMH271Kka/reEwSZkC7T+o9hZ4zi2CcLcY0DXj0qdId7vUKSJjEep c++s8ncFekh1MPhkOgNj8pk17OAESanmDwksmzh1j12lgA5lTFPrJeRNu6/isC2zyZhTwMWs k3LkcTa8ZXxh0RfWAqgx/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABtCNOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuY29tPokCOAQTAQIAIgUCWIo48QIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQcb6CRuU/KFc0eg/9GLD3wTQz9iZHMFbjiqTCitD7B6dTLV1C ddZVlC8Hm/TophPts1bWZORAmYIihHHI1EIF19+bfIr46pvfTu0yFrJDLOADMDH+Ufzsfy2v HSqqWV/nOSWGXzh8bgg/ncLwrIdEwBQBN9SDS6aqsglagvwFD91UCg/TshLlRxD5BOnuzfzI Leyx2c6YmH7Oa1R4MX9Jo79SaKwdHt2yRN3SochVtxCyafDlZsE/efp21pMiaK1HoCOZTBp5 VzrIP85GATh18pN7YR9CuPxxN0V6IzT7IlhS4Jgj0NXh6vi1DlmKspr+FOevu4RVXqqcNTSS E2rycB2v6cttH21UUdu/0FtMBKh+rv8+yD49FxMYnTi1jwVzr208vDdRU2v7Ij/TxYt/v4O8 V+jNRKy5Fevca/1xroQBICXsNoFLr10X5IjmhAhqIH8Atpz/89ItS3+HWuE4BHB6RRLM0gy8 T7rN6ja+KegOGikp/VTwBlszhvfLhyoyjXI44Tf3oLSFM+8+qG3B7MNBHOt60CQlMkq0fGXd mm4xENl/SSeHsiomdveeq7cNGpHi6i6ntZK33XJLwvyf00PD7tip/GUj0Dic/ZUsoPSTF/mG EpuQiUZs8X2xjK/AS/l3wa4Kz2tlcOKSKpIpna7V1+CMNkNzaCOlbv7QwprAerKYywPCoOSC 7P25Ag0EWIoHPgEQAMiUqvRBZNvPvki34O/dcTodvLSyOmK/MMBDrzN8Cnk302XfnGlW/YAQ csMWISKKSpStc6tmD+2Y0z9WjyRqFr3EGfH1RXSv9Z1vmfPzU42jsdZn667UxrRcVQXUgoKg QYx055Q2FdUeaZSaivoIBD9WtJq/66UPXRRr4H/+Y5FaUZx+gWNGmBT6a0S/GQnHb9g3nonD jmDKGw+YO4P6aEMxyy3k9PstaoiyBXnzQASzdOi39BgWQuZfIQjN0aW+Dm8kOAfT5i/yk59h VV6v3NLHBjHVw9kHli3jwvsizIX9X2W8tb1SefaVxqvqO1132AO8V9CbE1DcVT8fzICvGi42 FoV/k0QOGwq+LmLf0t04Q0csEl+h69ZcqeBSQcIMm/Ir+NorfCr6HjrB6lW7giBkQl6hhomn l1mtDP6MTdbyYzEiBFcwQD4terc7S/8ELRRybWQHQp7sxQM/Lnuhs77MgY/e6c5AVWnMKd/z MKm4ru7A8+8gdHeydrRQSWDaVbfy3Hup0Ia76J9FaolnjB8YLUOJPdhI2vbvNCQ2ipxw3Y3c KhVIpGYqwdvFIiz0Fej7wnJICIrpJs/+XLQHyqcmERn3s/iWwBpeogrx2Lf8AGezqnv9woq7 OSoWlwXDJiUdaqPEB/HmGfqoRRN20jx+OOvuaBMPAPb+aKJyle8zABEBAAGJAh8EGAECAAkF AliKBz4CGwwACgkQcb6CRuU/KFdacg/+M3V3Ti9JYZEiIyVhqs+yHb6NMI1R0kkAmzsGQ1jU zSQUz9AVMR6T7v2fIETTT/f5Oout0+Hi9cY8uLpk8CWno9V9eR/B7Ifs2pAA8lh2nW43FFwp IDiSuDbH6oTLmiGCB206IvSuaQCp1fed8U6yuqGFcnf0ZpJm/sILG2ECdFK9RYnMIaeqlNQm iZicBY2lmlYFBEaMXHoy+K7nbOuizPWdUKoKHq+tmZ3iA+qL5s6Qlm4trH28/fPpFuOmgP8P K+7LpYLNSl1oQUr+WlqilPAuLcCo5Vdl7M7VFLMq4xxY/dY99aZx0ZJQYFx0w/6UkbDdFLzN upT7NIN68lZRucImffiWyN7CjH23X3Tni8bS9ubo7OON68NbPz1YIaYaHmnVQCjDyDXkQoKC R82Vf9mf5slj0Vlpf+/Wpsv/TH8X32ajva37oEQTkWNMsDxyw3aPSps6MaMafcN7k60y2Wk/ TCiLsRHFfMHFY6/lq/c0ZdOsGjgpIK0G0z6et9YU6MaPuKwNY4kBdjPNBwHreucrQVUdqRRm RcxmGC6ohvpqVGfhT48ZPZKZEWM+tZky0mO7bhZYxMXyVjBn4EoNTsXy1et9Y1dU3HVJ8fod 5UqrNrzIQFbdeM0/JqSLrtlTcXKJ7cYFa9ZM2AP7UIN9n1UWxq+OPY9YMOewVfYtL8M= Message-ID: Date: Mon, 7 Oct 2019 18:36:14 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20191007091104.18095-4-jthumshirn@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 7.10.19 г. 12:11 ч., Johannes Thumshirn wrote: > From: David Sterba > > Export supported checksum algorithms via sysfs. > > Co-developed-by: David Sterba > Signed-off-by: Johannes Thumshirn > --- > fs/btrfs/ctree.c | 5 +++++ > fs/btrfs/ctree.h | 2 ++ > fs/btrfs/sysfs.c | 33 +++++++++++++++++++++++++++++++++ > 3 files changed, 40 insertions(+) > > diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c > index b66509ee62eb..5debd74dc61c 100644 > --- a/fs/btrfs/ctree.c > +++ b/fs/btrfs/ctree.c > @@ -53,6 +53,11 @@ const char *btrfs_super_csum_name(u16 csum_type) > return btrfs_csums[csum_type].name; > } > > +size_t btrfs_get_num_csums(void) > +{ > + return ARRAY_SIZE(btrfs_csums); > +} nit: This function is used only once and the ARRAY_SIZE() macro is descriptive enough, why not just remove it and opencoude the call to array_size > + > struct btrfs_path *btrfs_alloc_path(void) > { > return kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS); > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index d17e79a40930..0180554f6970 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -2165,6 +2165,8 @@ BTRFS_SETGET_STACK_FUNCS(super_uuid_tree_generation, struct btrfs_super_block, > > int btrfs_super_csum_size(const struct btrfs_super_block *s); > const char *btrfs_super_csum_name(u16 csum_type); > +size_t btrfs_get_num_csums(void); > + > > /* > * The leaf data grows from end-to-front in the node. > diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c > index f6d3c80f2e28..aeebbdfe1a98 100644 > --- a/fs/btrfs/sysfs.c > +++ b/fs/btrfs/sysfs.c > @@ -246,6 +246,28 @@ static umode_t btrfs_feature_visible(struct kobject *kobj, > return mode; > } > > +static ssize_t btrfs_supported_checksums_show(struct kobject *kobj, > + struct kobj_attribute *a, > + char *buf) > +{ > + ssize_t ret = 0; > + int i; > + > + for (i = 0; i < btrfs_get_num_csums(); i++) { > + /* > + * This "trick" only works as long as 'enum btrfs_csum_type' has > + * no holes in it > + */ > + ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s", > + (i == 0 ? "" : ", "), > + btrfs_super_csum_name(i)); > + > + } > + > + ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n"); > + return ret; > +} > + > BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF); > BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL); > BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS); > @@ -259,6 +281,14 @@ BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES); > BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID); > BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE); > > +static struct btrfs_feature_attr btrfs_attr_features_checksums_name = { > + .kobj_attr = __INIT_KOBJ_ATTR(supported_checksums, S_IRUGO, > + btrfs_supported_checksums_show, > + NULL), > + .feature_set = FEAT_INCOMPAT, > + .feature_bit = 0, > +}; > + > static struct attribute *btrfs_supported_feature_attrs[] = { > BTRFS_FEAT_ATTR_PTR(mixed_backref), > BTRFS_FEAT_ATTR_PTR(default_subvol), > @@ -272,6 +302,9 @@ static struct attribute *btrfs_supported_feature_attrs[] = { > BTRFS_FEAT_ATTR_PTR(no_holes), > BTRFS_FEAT_ATTR_PTR(metadata_uuid), > BTRFS_FEAT_ATTR_PTR(free_space_tree), > + > + &btrfs_attr_features_checksums_name.kobj_attr.attr, > + > NULL > }; > >