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Tue, 19 Feb 2019 12:00:31 +0000 (UTC) Subject: Re: [PATCH v2] btrfs: factor our read/write stage off csum_tree_block() into its callers To: Johannes Thumshirn , David Sterba Cc: Linux BTRFS Mailinglist , Qu Wenruo References: <20190219105829.19849-1-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: Tue, 19 Feb 2019 14:00:30 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190219105829.19849-1-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 19.02.19 г. 12:58 ч., Johannes Thumshirn wrote: > Currently csum_tree_block() does two things, first it as it's name > suggests it calculates the checksum for a tree-block. But it also writes > this checksum to disk or reads an extent_buffer from disk and compares the > checksum with the calculated checksum, depending on the verify argument. > > Furthermore one of the two callers passes in '1' for the verify argument, > the other one passes in '0'. > > For clarity and less layering violations, factor out the second stage in > csum_tree_block()'s callers. > > Suggested-by: Nikolay Borisov > Reviewed-by: Qu Wenruo > Reviewed-by: Nikolay Borisov > Signed-off-by: Johannes Thumshirn > > --- > Changes to v1: > - return error from csum_tree_buffer() in csum_dirty_buffer() instead of > EUCLEAN (Nikolay) > --- > fs/btrfs/disk-io.c | 53 +++++++++++++++++++++++++++++------------------------ > 1 file changed, 29 insertions(+), 24 deletions(-) > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 5216e7b3f9ad..56f5fe732be5 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -263,12 +263,9 @@ void btrfs_csum_final(u32 crc, u8 *result) > * compute the csum for a btree block, and either verify it or write it > * into the csum field of the block. > */ > -static int csum_tree_block(struct btrfs_fs_info *fs_info, > - struct extent_buffer *buf, > - int verify) > +static int csum_tree_block(struct extent_buffer *buf, > + u8 *result) > { > - u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); > - char result[BTRFS_CSUM_SIZE]; > unsigned long len; > unsigned long cur_len; > unsigned long offset = BTRFS_CSUM_SIZE; > @@ -300,23 +297,6 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info, > > btrfs_csum_final(crc, result); > > - if (verify) { > - if (memcmp_extent_buffer(buf, result, 0, csum_size)) { > - u32 val; > - u32 found = 0; > - memcpy(&found, result, csum_size); > - > - read_extent_buffer(buf, &val, 0, csum_size); > - btrfs_warn_rl(fs_info, > - "%s checksum verify failed on %llu wanted %X found %X level %d", > - fs_info->sb->s_id, buf->start, > - val, found, btrfs_header_level(buf)); > - return -EUCLEAN; > - } > - } else { > - write_extent_buffer(buf, result, 0, csum_size); > - } > - > return 0; > } > > @@ -533,7 +513,10 @@ static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page) > { > u64 start = page_offset(page); > u64 found_start; > + u8 result[BTRFS_CSUM_SIZE]; > + u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); > struct extent_buffer *eb; > + int ret = 0; > > eb = (struct extent_buffer *)page->private; > if (page != eb->pages[0]) > @@ -552,7 +535,12 @@ static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page) > ASSERT(memcmp_extent_buffer(eb, fs_info->fs_devices->metadata_uuid, > btrfs_header_fsid(), BTRFS_FSID_SIZE) == 0); > > - return csum_tree_block(fs_info, eb, 0); > + ret = csum_tree_block(eb, result); > + if (WARN_ON(ret)) > + return ret; You are not handling the case where csum-tree_block returns a positive number. It should be translated to a negative value. > + > + write_extent_buffer(eb, result, 0, csum_size); > + return ret; > } > > static int check_tree_block_fsid(struct btrfs_fs_info *fs_info, > @@ -595,7 +583,9 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio, > struct extent_buffer *eb; > struct btrfs_root *root = BTRFS_I(page->mapping->host)->root; > struct btrfs_fs_info *fs_info = root->fs_info; > + u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); > int ret = 0; > + char result[BTRFS_CSUM_SIZE]; > int reads_done; > > if (!page->private) > @@ -642,10 +632,25 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio, > btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb), > eb, found_level); > > - ret = csum_tree_block(fs_info, eb, 1); > + ret = csum_tree_block(eb, result); > if (ret) > goto err; > > + if (memcmp_extent_buffer(eb, result, 0, csum_size)) { > + u32 val; > + u32 found = 0; > + > + memcpy(&found, result, csum_size); > + > + read_extent_buffer(eb, &val, 0, csum_size); > + btrfs_warn_rl(fs_info, > + "%s checksum verify failed on %llu wanted %x found %x level %d", > + fs_info->sb->s_id, eb->start, > + val, found, btrfs_header_level(eb)); > + ret = -EUCLEAN; > + goto err; > + } > + > /* > * If this is a leaf block and it is corrupt, set the corrupt bit so > * that we don't try and read the other copies of this block, just >