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Wed, 4 Sep 2019 06:53:49 -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 9433FAD20; Wed, 4 Sep 2019 10:53:47 +0000 (UTC) Subject: Re: [PATCH 1/4] btrfs-progs: check/common: Make repair_imode_common() to handle inodes in subvolume trees To: Qu Wenruo , WenRuo Qu , linux-btrfs@vger.kernel.org References: <20190903082407.13927-1-wqu@suse.com> <20190903082407.13927-2-wqu@suse.com> <7cfbd72b-d8e9-695b-0576-d9dda1010228@suse.com> <2bd09938-f462-6e2f-1dbd-a326e0c6f159@gmx.com> 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: Wed, 4 Sep 2019 13:53:45 +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: <2bd09938-f462-6e2f-1dbd-a326e0c6f159@gmx.com> 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 4.09.19 г. 11:30 ч., Qu Wenruo wrote: > > > On 2019/9/4 下午3:37, Nikolay Borisov wrote: >> >> >> On 3.09.19 г. 11:24 ч., Qu Wenruo wrote: >>> Before this patch, repair_imode_common() can only handle two types of >>> inodes: >>> - Free space cache inodes >>> - ROOT DIR inodes >>> >>> For inodes in subvolume trees, the problem is how to determine the >>> correct imode, thus it was not implemented. >>> >>> However there are more reports of incorrect imode in subvolume trees, we >>> need to support such fix. >>> >>> So this patch adds a new function, detect_imode(), to detect (or call it >>> educated guess) imode for inodes in subvolume trees. >>> >>> Signed-off-by: Qu Wenruo >>> --- >>> check/mode-common.c | 96 +++++++++++++++++++++++++++++++++++++++------ >>> 1 file changed, 83 insertions(+), 13 deletions(-) >>> >>> diff --git a/check/mode-common.c b/check/mode-common.c >>> index 195b6efaa7aa..807d7daf98a6 100644 >>> --- a/check/mode-common.c >>> +++ b/check/mode-common.c >>> @@ -836,6 +836,80 @@ int reset_imode(struct btrfs_trans_handle *trans, struct btrfs_root *root, >>> return ret; >>> } >>> >>> +static int detect_imode(struct btrfs_root *root, struct btrfs_path *path, >>> + u32 *imode_ret) >>> +{ >>> + struct btrfs_key key; >>> + struct btrfs_inode_item *iitem; >>> + const u32 priv = 0700; >>> + u64 ino; >>> + u32 imode = S_IFREG; >>> + int ret = 0; >>> + >>> + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); >>> + ino = key.objectid; >>> + iitem = btrfs_item_ptr(path->nodes[0], path->slots[0], >>> + struct btrfs_inode_item); >>> + >>> + /* >>> + * Both CHR and BLK uses rdev, no way to distinguish them, so fall back >>> + * to BLK. >>> + */ >>> + if (btrfs_inode_rdev(path->nodes[0], iitem) != 0) { >>> + imode = S_IFBLK; >>> + goto out; >>> + } >>> + >>> + /* root inode */ >>> + if (ino == BTRFS_FIRST_FREE_OBJECTID) { >>> + imode = S_IFDIR; >>> + goto out; >>> + } >>> + >>> + while (1) { >>> + ret = btrfs_next_item(root, path); >>> + if (ret > 0) { >>> + /* No determining result found, falls back to REG */ >>> + ret = 0; >>> + goto out; >>> + } >>> + if (ret < 0) >>> + goto out; >>> + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); >>> + if (key.objectid != ino) >>> + goto out; >>> + >>> + /* >>> + * We ignore some types to make life easier: >>> + * - INODE_REF >>> + * We need to do a full tree search, which can fail for >>> + * corrupted fs, but not worthy compared to other easier >>> + * to determine types. >>> + * - XATTR >>> + * Both REG and DIR can have xattr, so not useful >>> + */ >>> + switch (key.type) { >>> + case BTRFS_DIR_ITEM_KEY: >>> + case BTRFS_DIR_INDEX_KEY: >>> + imode = S_IFDIR; >>> + goto out; >>> + case BTRFS_EXTENT_DATA_KEY: >>> + /* >>> + * Both REG and LINK could have EXTENT_DATA. >>> + * We just fall back to REG as user can inspect the >>> + * content. >>> + */ >>> + imode = S_IFREG; >>> + goto out; >>> + } >>> + } >>> + >>> +out: >>> + /* Set default value even when something wrong happened */ >>> + *imode_ret = (imode | priv); >>> + return ret; >>> +} >>> + >>> /* >>> * Reset the inode mode of the inode specified by @path. >>> * >>> @@ -852,22 +926,18 @@ int repair_imode_common(struct btrfs_root *root, struct btrfs_path *path) >>> u32 imode; >>> int ret; >>> >>> - if (root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) { >>> - error( >>> - "repair inode mode outside of root tree is not supported yet"); >>> - return -ENOTTY; >>> - } >>> btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); >>> ASSERT(key.type == BTRFS_INODE_ITEM_KEY); >>> - if (key.objectid != BTRFS_ROOT_TREE_DIR_OBJECTID && >>> - !is_fstree(key.objectid)) { >>> - error("unsupported ino %llu", key.objectid); >>> - return -ENOTTY; >>> + if (root->objectid == BTRFS_ROOT_TREE_OBJECTID) { >>> + /* In root tree we only have two possible imode */ >>> + if (key.objectid == BTRFS_ROOT_TREE_OBJECTID) >>> + imode = S_IFDIR | 0755; >>> + else >>> + imode = S_IFREG | 0600; >>> + } else { >>> + detect_imode(root, path, &imode); >>> + /* Ignore error returned, just use the default value returned */ >> >> Is this safe enough though? > > It depends. But I'd say if we failed in detect_imode(), then it doesn't > matter whatever the type we're putting here. > >> What if due to an error a directory is >> corrected to be file? > > If a failure happens, it means btrfs-progs fails to read the next leaf. > Then it really doesn't make much sense whatever the type is. > > But I get your point, indeed we should error out without trying out to > fix the inode. > > I'll change this behavior in next version. IMO the goal of btrfs-progs should be to make a broken filesystem better and not replace one type of breakage with potentially another. In such cases we ought to break out gracefully. > > Thanks, > Qu > >> Let's not forget the context we are oprating here >> - a broken fs so it's possible (if not likely) that any of the search >> functions inside detect_imode could return negative error value. OTOH >> I'd expect the transaction commit to fail if that's the case e.g. faulty >> device. >> >>> } >>> - if (key.objectid == BTRFS_ROOT_TREE_DIR_OBJECTID) >>> - imode = 040755; >>> - else >>> - imode = 0100600; >>> >>> trans = btrfs_start_transaction(root, 1); >>> if (IS_ERR(trans)) { >>> >