On 28.02.19 г. 8:54 ч., Anand Jain wrote:
> From: Anand Jain <Anand.Jain@xxxxxxxxxx>
>
> 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 <dev> [<dev>..]'
> 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 <anand.jain@xxxxxxxxxx>
> 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] <device>::
> +*dump-tree* [options] <device> [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 <tree_id>::::
> 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 <unistd.h>
> #include <uuid/uuid.h>
> #include <getopt.h>
> +#include <fcntl.h>
>
> #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] <device> [<device> ..]",
> "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 <block_num> print info from the specified block only",
> "-t|--tree <tree_id> print only tree with the given id (string or number)",
> "--follow use with -b, to show all children tree blocks of <block_num>",
> + "--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);
>
