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Mon, 11 Mar 2019 10:11:21 +0000 (UTC) Subject: Re: [PATCH v4] btrfs-progs: dump-tree: add noscan option To: Anand Jain , linux-btrfs@vger.kernel.org References: <1551336865-9954-1-git-send-email-anand.jain@oracle.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: Mon, 11 Mar 2019 12:11:20 +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: <1551336865-9954-1-git-send-email-anand.jain@oracle.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 28.02.19 г. 8:54 ч., Anand Jain wrote: > From: Anand Jain > > There is no way to dump tree from a disk in the degraded mode. > Such as, when you specify a device for the cli 'btrfs inspect > dump-tree /dev/sda' it would invariably scan for its partner devices > to built and print the tree. This approach at times defeats the purpose. define "at times" which are those times? > Suppose in RAID1 if you want to review each mirror separately as of now > there is no way you can do that. So this patch adds an option --noscan > for example: > 'btrfs inspect dump-tree --noscan [..]' > with which it shall not scan for the other devices to report the tree, and > helps debug RAID1s. This example contradicts what the code is doing, with this patch you will call btrfs_scan_one_device for every device passed to the noscan option? > > Signed-off-by: Anand Jain > v3->v4: change the patch title. > collapse scan_args() to its only parent cmd_inspect_dump_tree() > (it was bit confusing). > update the change log. > update usage. > update man page. > v2->v3: make it scalable for more than two disks in noscan mode > v1->v2: rename --degraded to --noscan So what problem is this actually trying to solve? The following succeeds for me with btrfs-progs 4.17.1: root@ubuntu-virtual:~# losetup -f file1.img root@ubuntu-virtual:~# losetup -f file2.img root@ubuntu-virtual:~# mkfs.btrfs -m raid1 /dev/loop1 /dev/loop0 losetup -d /dev/loop1 root@ubuntu-virtual:~# mount /dev/loop0 /media/scratch/ mount: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so. root@ubuntu-virtual:~# btrfs inspect-internal dump-tree /dev/loop0 btrfs-progs v4.17.1 warning, device 1 is missing root tree leaf 30556160 items 10 free space 13173 generation 5 owner ROOT_TREE leaf 30556160 flags 0x1(WRITTEN) backref revision 1 fs uuid 8727408c-b1af-4c14-b63b-51b12bcff933 chunk uuid 5ebde928-324f-42d0-98c6-f953d680fc21 item 0 key (EXTENT_TREE ROOT_ITEM 0) itemoff 15844 itemsize 439 generation 5 root_dirid 0 bytenr 30523392 level 0 refs 1 ................. Your changelog definitely needs rewriting to make it clear what you are trying to do. > --- > Documentation/btrfs-inspect-internal.asciidoc | 5 ++- > cmds-inspect-dump-tree.c | 57 ++++++++++++++++++++------- > 2 files changed, 47 insertions(+), 15 deletions(-) > > diff --git a/Documentation/btrfs-inspect-internal.asciidoc b/Documentation/btrfs-inspect-internal.asciidoc > index 381497d284b8..f9d7f1c58f00 100644 > --- a/Documentation/btrfs-inspect-internal.asciidoc > +++ b/Documentation/btrfs-inspect-internal.asciidoc > @@ -61,7 +61,7 @@ specify which mirror to print, valid values are 0, 1 and 2 and the superblock > must be present on the device with a valid signature, can be used together with > '--force' > > -*dump-tree* [options] :: > +*dump-tree* [options] [device...]:: > (replaces the standalone tool *btrfs-debug-tree*) > + > Dump tree structures from a given device in textual form, expand keys to human > @@ -95,6 +95,9 @@ intermixed in the output > --bfs:::: > use breadth-first search to print trees. the nodes are printed before all > leaves > +--noscan:::: > +do not scan the system for other partner device(s), only use the device(s) > +provided in the argument > -t :::: > print only the tree with the specified ID, where the ID can be numerical or > common name in a flexible human readable form > diff --git a/cmds-inspect-dump-tree.c b/cmds-inspect-dump-tree.c > index ad5345b4f1db..9dd040e5de17 100644 > --- a/cmds-inspect-dump-tree.c > +++ b/cmds-inspect-dump-tree.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > > #include "kerncompat.h" > #include "radix-tree.h" > @@ -185,7 +186,7 @@ static u64 treeid_from_string(const char *str, const char **end) > } > > const char * const cmd_inspect_dump_tree_usage[] = { > - "btrfs inspect-internal dump-tree [options] device", > + "btrfs inspect-internal dump-tree [options] [ ..]", > "Dump tree structures from a given device", > "Dump tree structures from a given device in textual form, expand keys to human", > "readable equivalents where possible.", > @@ -200,6 +201,7 @@ const char * const cmd_inspect_dump_tree_usage[] = { > "-b|--block print info from the specified block only", > "-t|--tree print only tree with the given id (string or number)", > "--follow use with -b, to show all children tree blocks of ", > + "--noscan do not scan for the partner device(s)", > NULL > }; > > @@ -214,7 +216,7 @@ int cmd_inspect_dump_tree(int argc, char **argv) > struct btrfs_disk_key disk_key; > struct btrfs_key found_key; > char uuidbuf[BTRFS_UUID_UNPARSED_SIZE]; > - int ret; > + int ret = 0; > int slot; > int extent_only = 0; > int device_only = 0; > @@ -222,6 +224,7 @@ int cmd_inspect_dump_tree(int argc, char **argv) > int roots_only = 0; > int root_backups = 0; > int traverse = BTRFS_PRINT_TREE_DEFAULT; > + int dev_optind; > unsigned open_ctree_flags; > u64 block_only = 0; > struct btrfs_root *tree_root_scan; > @@ -239,8 +242,8 @@ int cmd_inspect_dump_tree(int argc, char **argv) > optind = 0; > while (1) { > int c; > - enum { GETOPT_VAL_FOLLOW = 256, GETOPT_VAL_DFS, > - GETOPT_VAL_BFS }; > + enum { GETOPT_VAL_FOLLOW = 256, GETOPT_VAL_DFS, GETOPT_VAL_BFS, > + GETOPT_VAL_NOSCAN}; > static const struct option long_options[] = { > { "extents", no_argument, NULL, 'e'}, > { "device", no_argument, NULL, 'd'}, > @@ -252,6 +255,7 @@ int cmd_inspect_dump_tree(int argc, char **argv) > { "follow", no_argument, NULL, GETOPT_VAL_FOLLOW }, > { "bfs", no_argument, NULL, GETOPT_VAL_BFS }, > { "dfs", no_argument, NULL, GETOPT_VAL_DFS }, > + { "noscan", no_argument, NULL, GETOPT_VAL_NOSCAN }, > { NULL, 0, NULL, 0 } > }; > > @@ -313,24 +317,49 @@ int cmd_inspect_dump_tree(int argc, char **argv) > case GETOPT_VAL_BFS: > traverse = BTRFS_PRINT_TREE_BFS; > break; > + case GETOPT_VAL_NOSCAN: > + open_ctree_flags |= OPEN_CTREE_NO_DEVICES; > + break; > default: > usage(cmd_inspect_dump_tree_usage); > } > } > > - if (check_argc_exact(argc - optind, 1)) > + if (check_argc_min(argc - optind, 1)) > usage(cmd_inspect_dump_tree_usage); > > - ret = check_arg_type(argv[optind]); > - if (ret != BTRFS_ARG_BLKDEV && ret != BTRFS_ARG_REG) { > - if (ret < 0) { > - errno = -ret; > - error("invalid argument %s: %m", argv[optind]); > - } else { > - error("not a block device or regular file: %s", > - argv[optind]); > + dev_optind = optind; > + while (dev_optind < argc) { > + int fd; > + struct btrfs_fs_devices *fs_devices; > + u64 num_devices; > + > + ret = check_arg_type(argv[optind]); > + if (ret != BTRFS_ARG_BLKDEV && ret != BTRFS_ARG_REG) { > + if (ret < 0) { > + errno = -ret; > + error("invalid argument %s: %m", argv[dev_optind]); > + } else { > + error("not a block device or regular file: %s", > + argv[dev_optind]); > + } > } > - goto out; > + fd = open(argv[dev_optind], O_RDONLY); > + if (fd < 0) { > + error("cannot open %s: %m", argv[dev_optind]); > + return -EINVAL; > + } > + ret = btrfs_scan_one_device(fd, argv[dev_optind], &fs_devices, > + &num_devices, > + BTRFS_SUPER_INFO_OFFSET, > + SBREAD_DEFAULT); > + close(fd); > + if (ret) { > + error("device scan %s: %s", argv[dev_optind], > + strerror(-ret)); > + return ret; > + } > + dev_optind++; > } > > printf("%s\n", PACKAGE_STRING); >