[v7,RESEND,Rebased] btrfs-progs: dump-tree: add noscan option
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Message ID 20190626083017.1833-1-anand.jain@oracle.com
State New
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  • [v7,RESEND,Rebased] btrfs-progs: dump-tree: add noscan option
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Commit Message

Anand Jain June 26, 2019, 8:30 a.m. UTC
From: Anand Jain <Anand.Jain@oracle.com>

The cli 'btrfs inspect dump-tree <dev>' will scan for the partner devices
if any by default.

So as of now you can not inspect each mirrored device independently.

This patch adds noscan option, which when used won't scan the system for
the partner devices, instead it just uses the devices provided in the
argument.

For example:
  btrfs inspect dump-tree --noscan <dev> [<dev>..]

This helps to debug degraded raid1 and raid10.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
v6->v7: rebase on latest btrfs-progs::devel
v5->v6: rebase on latest btrfs-progs::devel
v4->v5: nit: use %m to print error string.
	changelog update.
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
 Documentation/btrfs-inspect-internal.asciidoc |  5 +-
 cmds-inspect-dump-tree.c                      | 53 ++++++++++++++-----
 2 files changed, 45 insertions(+), 13 deletions(-)

Comments

Anand Jain July 2, 2019, 8:09 a.m. UTC | #1
Ping?



On 26/6/19 4:30 PM, Anand Jain wrote:
> From: Anand Jain <Anand.Jain@oracle.com>
> 
> The cli 'btrfs inspect dump-tree <dev>' will scan for the partner devices
> if any by default.
> 
> So as of now you can not inspect each mirrored device independently.
> 
> This patch adds noscan option, which when used won't scan the system for
> the partner devices, instead it just uses the devices provided in the
> argument.
> 
> For example:
>    btrfs inspect dump-tree --noscan <dev> [<dev>..]
> 
> This helps to debug degraded raid1 and raid10.
> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> ---
> v6->v7: rebase on latest btrfs-progs::devel
> v5->v6: rebase on latest btrfs-progs::devel
> v4->v5: nit: use %m to print error string.
> 	changelog update.
> 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
>   Documentation/btrfs-inspect-internal.asciidoc |  5 +-
>   cmds-inspect-dump-tree.c                      | 53 ++++++++++++++-----
>   2 files changed, 45 insertions(+), 13 deletions(-)
> 
> diff --git a/Documentation/btrfs-inspect-internal.asciidoc b/Documentation/btrfs-inspect-internal.asciidoc
> index 210f18c30a40..c9962ab3b548 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
> +--device::::
> +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 1588a0b0774b..8e13b4335a5d 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)
>   }
>   
>   static 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.",
> @@ -201,6 +202,7 @@ static const char * const cmd_inspect_dump_tree_usage[] = {
>   	"                       can be specified multiple times",
>   	"-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
>   };
>   
> @@ -297,7 +299,7 @@ static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
>   	struct btrfs_key found_key;
>   	struct cache_tree block_root;	/* for multiple --block parameters */
>   	char uuidbuf[BTRFS_UUID_UNPARSED_SIZE];
> -	int ret;
> +	int ret = 0;
>   	int slot;
>   	int extent_only = 0;
>   	int device_only = 0;
> @@ -305,6 +307,7 @@ static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
>   	int roots_only = 0;
>   	int root_backups = 0;
>   	int traverse = BTRFS_PRINT_TREE_DEFAULT;
> +	int dev_optind;
>   	unsigned open_ctree_flags;
>   	u64 block_bytenr;
>   	struct btrfs_root *tree_root_scan;
> @@ -323,8 +326,8 @@ static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
>   	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'},
> @@ -336,6 +339,7 @@ static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
>   			{ "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 }
>   		};
>   
> @@ -400,24 +404,49 @@ static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
>   		case GETOPT_VAL_BFS:
>   			traverse = BTRFS_PRINT_TREE_BFS;
>   			break;
> +		case GETOPT_VAL_NOSCAN:
> +			open_ctree_flags |= OPEN_CTREE_NO_DEVICES;
> +			break;
>   		default:
>   			usage_unknown_option(cmd, argv);
>   		}
>   	}
>   
> -	if (check_argc_exact(argc - optind, 1))
> +	if (check_argc_min(argc - optind, 1))
>   		return 1;
>   
> -	ret = check_arg_type(argv[optind]);
> -	if (ret != BTRFS_ARG_BLKDEV && ret != BTRFS_ARG_REG) {
> +	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]);
> +			}
> +		}
> +		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 < 0) {
>   			errno = -ret;
> -			error("invalid argument %s: %m", argv[optind]);
> -		} else {
> -			error("not a block device or regular file: %s",
> -			      argv[optind]);
> +			error("device scan %s: %m", argv[dev_optind]);
> +			return ret;
>   		}
> -		goto out;
> +		dev_optind++;
>   	}
>   
>   	printf("%s\n", PACKAGE_STRING);
>
David Sterba July 3, 2019, 12:53 p.m. UTC | #2
On Wed, Jun 26, 2019 at 01:30:17AM -0700, Anand Jain wrote:
> From: Anand Jain <Anand.Jain@oracle.com>
> 
> The cli 'btrfs inspect dump-tree <dev>' will scan for the partner devices
> if any by default.
> 
> So as of now you can not inspect each mirrored device independently.
> 
> This patch adds noscan option, which when used won't scan the system for
> the partner devices, instead it just uses the devices provided in the
> argument.
> 
> For example:
>   btrfs inspect dump-tree --noscan <dev> [<dev>..]
> 
> This helps to debug degraded raid1 and raid10.
> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>

Added to devel, with some minor tweaks. Sorry for the delay.

> ---
> v6->v7: rebase on latest btrfs-progs::devel
> v5->v6: rebase on latest btrfs-progs::devel
> v4->v5: nit: use %m to print error string.
> 	changelog update.
> 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
>  Documentation/btrfs-inspect-internal.asciidoc |  5 +-
>  cmds-inspect-dump-tree.c                      | 53 ++++++++++++++-----
>  2 files changed, 45 insertions(+), 13 deletions(-)
> 
> diff --git a/Documentation/btrfs-inspect-internal.asciidoc b/Documentation/btrfs-inspect-internal.asciidoc
> index 210f18c30a40..c9962ab3b548 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
> +--device::::

Minor typo, --noscan, fixed.
David Sterba July 3, 2019, 1:02 p.m. UTC | #3
On Wed, Jun 26, 2019 at 01:30:17AM -0700, Anand Jain wrote:
> From: Anand Jain <Anand.Jain@oracle.com>
> 
> The cli 'btrfs inspect dump-tree <dev>' will scan for the partner devices
> if any by default.
> 
> So as of now you can not inspect each mirrored device independently.
> 
> This patch adds noscan option, which when used won't scan the system for
> the partner devices, instead it just uses the devices provided in the
> argument.
> 
> For example:
>   btrfs inspect dump-tree --noscan <dev> [<dev>..]

There were some concerns regarding the option name, I find --noscan
acceptable as the meaning of 'scan' is established, besides that
--device already exists for dump-tree.
David Sterba July 3, 2019, 4:09 p.m. UTC | #4
On Wed, Jun 26, 2019 at 01:30:17AM -0700, Anand Jain wrote:
> From: Anand Jain <Anand.Jain@oracle.com>
> 
> The cli 'btrfs inspect dump-tree <dev>' will scan for the partner devices
> if any by default.
> 
> So as of now you can not inspect each mirrored device independently.
> 
> This patch adds noscan option, which when used won't scan the system for
> the partner devices, instead it just uses the devices provided in the
> argument.
> 
> For example:
>   btrfs inspect dump-tree --noscan <dev> [<dev>..]
> 
> This helps to debug degraded raid1 and raid10.
> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>

This makes misc-test/021-image-multi-devices fail

====== RUN CHECK root_helper mount /dev/loop2 .../btrfs-progs/tests//mnt
====== RUN CHECK md5sum .../btrfs-progs/tests//mnt/foobar
md5sum: .../btrfs-progs/tests//mnt/foobar: Input/output error
failed: md5sum .../btrfs-progs/tests//mnt/foobar
====== RUN CHECK root_helper umount .../btrfs-progs/tests//mnt
====== RUN CHECK root_helper losetup -d /dev/loop2
====== RUN CHECK root_helper losetup -d /dev/loop3

note the md5sum error, that does not happen otherwise
Anand Jain July 3, 2019, 10:16 p.m. UTC | #5
> On 4 Jul 2019, at 12:09 AM, David Sterba <dsterba@suse.cz> wrote:
> 
> On Wed, Jun 26, 2019 at 01:30:17AM -0700, Anand Jain wrote:
>> From: Anand Jain <Anand.Jain@oracle.com>
>> 
>> The cli 'btrfs inspect dump-tree <dev>' will scan for the partner devices
>> if any by default.
>> 
>> So as of now you can not inspect each mirrored device independently.
>> 
>> This patch adds noscan option, which when used won't scan the system for
>> the partner devices, instead it just uses the devices provided in the
>> argument.
>> 
>> For example:
>>  btrfs inspect dump-tree --noscan <dev> [<dev>..]
>> 
>> This helps to debug degraded raid1 and raid10.
>> 
>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> 
> This makes misc-test/021-image-multi-devices fail
> 
> ====== RUN CHECK root_helper mount /dev/loop2 .../btrfs-progs/tests//mnt
> ====== RUN CHECK md5sum .../btrfs-progs/tests//mnt/foobar
> md5sum: .../btrfs-progs/tests//mnt/foobar: Input/output error
> failed: md5sum .../btrfs-progs/tests//mnt/foobar
> ====== RUN CHECK root_helper umount .../btrfs-progs/tests//mnt
> ====== RUN CHECK root_helper losetup -d /dev/loop2
> ====== RUN CHECK root_helper losetup -d /dev/loop3
> 
> note the md5sum error, that does not happen otherwise


I am on devel. It runs fine. Test-misc/021 doesn’t use dump-tree at all.
Its strange that mnt/foobar fails to read in your case.

----
[root@dvm btrfs-progs]# make TEST=021\* test-misc
    [LD]     fssum
    [TEST]   misc-tests.sh
    [TEST/misc]   021-image-multi-devices
[root@dvm btrfs-progs]# 
[root@dvm btrfs-progs]# 
[root@dvm btrfs-progs]# 
[root@dvm btrfs-progs]# gl | head -1
299892f3c43d btrfs-progs: dump-tree: add noscan option
[root@dvm btrfs-progs]# make all
make: Nothing to be done for `all'.
[root@dvm btrfs-progs]# 
------
David Sterba July 3, 2019, 11:39 p.m. UTC | #6
On Thu, Jul 04, 2019 at 06:16:54AM +0800, Anand Jain wrote:
> 
> 
> > On 4 Jul 2019, at 12:09 AM, David Sterba <dsterba@suse.cz> wrote:
> > 
> > On Wed, Jun 26, 2019 at 01:30:17AM -0700, Anand Jain wrote:
> >> From: Anand Jain <Anand.Jain@oracle.com>
> >> 
> >> The cli 'btrfs inspect dump-tree <dev>' will scan for the partner devices
> >> if any by default.
> >> 
> >> So as of now you can not inspect each mirrored device independently.
> >> 
> >> This patch adds noscan option, which when used won't scan the system for
> >> the partner devices, instead it just uses the devices provided in the
> >> argument.
> >> 
> >> For example:
> >>  btrfs inspect dump-tree --noscan <dev> [<dev>..]
> >> 
> >> This helps to debug degraded raid1 and raid10.
> >> 
> >> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> > 
> > This makes misc-test/021-image-multi-devices fail
> > 
> > ====== RUN CHECK root_helper mount /dev/loop2 .../btrfs-progs/tests//mnt
> > ====== RUN CHECK md5sum .../btrfs-progs/tests//mnt/foobar
> > md5sum: .../btrfs-progs/tests//mnt/foobar: Input/output error
> > failed: md5sum .../btrfs-progs/tests//mnt/foobar
> > ====== RUN CHECK root_helper umount .../btrfs-progs/tests//mnt
> > ====== RUN CHECK root_helper losetup -d /dev/loop2
> > ====== RUN CHECK root_helper losetup -d /dev/loop3
> > 
> > note the md5sum error, that does not happen otherwise
> 
> 
> I am on devel. It runs fine. Test-misc/021 doesn’t use dump-tree at all.
> Its strange that mnt/foobar fails to read in your case.

Sorry, I replied to the wrong patch, it's the other one "btrfs-progs:
dump-tree: add noscan option".
Anand Jain July 4, 2019, 1:29 a.m. UTC | #7
> On 4 Jul 2019, at 7:39 AM, David Sterba <dsterba@suse.cz> wrote:
> 
> On Thu, Jul 04, 2019 at 06:16:54AM +0800, Anand Jain wrote:
>> 
>> 
>>> On 4 Jul 2019, at 12:09 AM, David Sterba <dsterba@suse.cz> wrote:
>>> 
>>> On Wed, Jun 26, 2019 at 01:30:17AM -0700, Anand Jain wrote:
>>>> From: Anand Jain <Anand.Jain@oracle.com>
>>>> 
>>>> The cli 'btrfs inspect dump-tree <dev>' will scan for the partner devices
>>>> if any by default.
>>>> 
>>>> So as of now you can not inspect each mirrored device independently.
>>>> 
>>>> This patch adds noscan option, which when used won't scan the system for
>>>> the partner devices, instead it just uses the devices provided in the
>>>> argument.
>>>> 
>>>> For example:
>>>> btrfs inspect dump-tree --noscan <dev> [<dev>..]
>>>> 
>>>> This helps to debug degraded raid1 and raid10.
>>>> 
>>>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
>>> 
>>> This makes misc-test/021-image-multi-devices fail
>>> 
>>> ====== RUN CHECK root_helper mount /dev/loop2 .../btrfs-progs/tests//mnt
>>> ====== RUN CHECK md5sum .../btrfs-progs/tests//mnt/foobar
>>> md5sum: .../btrfs-progs/tests//mnt/foobar: Input/output error
>>> failed: md5sum .../btrfs-progs/tests//mnt/foobar
>>> ====== RUN CHECK root_helper umount .../btrfs-progs/tests//mnt
>>> ====== RUN CHECK root_helper losetup -d /dev/loop2
>>> ====== RUN CHECK root_helper losetup -d /dev/loop3
>>> 
>>> note the md5sum error, that does not happen otherwise
>> 
>> 
>> I am on devel. It runs fine. Test-misc/021 doesn’t use dump-tree at all.
>> Its strange that mnt/foobar fails to read in your case.
> 
> Sorry, I replied to the wrong patch,


> it's the other one "btrfs-progs:
> dump-tree: add noscan option”.

 Typo in the other one? Because "dump-tree: add noscan option” is this.

Patch
diff mbox series

diff --git a/Documentation/btrfs-inspect-internal.asciidoc b/Documentation/btrfs-inspect-internal.asciidoc
index 210f18c30a40..c9962ab3b548 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
+--device::::
+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 1588a0b0774b..8e13b4335a5d 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)
 }
 
 static 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.",
@@ -201,6 +202,7 @@  static const char * const cmd_inspect_dump_tree_usage[] = {
 	"                       can be specified multiple times",
 	"-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
 };
 
@@ -297,7 +299,7 @@  static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
 	struct btrfs_key found_key;
 	struct cache_tree block_root;	/* for multiple --block parameters */
 	char uuidbuf[BTRFS_UUID_UNPARSED_SIZE];
-	int ret;
+	int ret = 0;
 	int slot;
 	int extent_only = 0;
 	int device_only = 0;
@@ -305,6 +307,7 @@  static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
 	int roots_only = 0;
 	int root_backups = 0;
 	int traverse = BTRFS_PRINT_TREE_DEFAULT;
+	int dev_optind;
 	unsigned open_ctree_flags;
 	u64 block_bytenr;
 	struct btrfs_root *tree_root_scan;
@@ -323,8 +326,8 @@  static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
 	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'},
@@ -336,6 +339,7 @@  static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
 			{ "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 }
 		};
 
@@ -400,24 +404,49 @@  static int cmd_inspect_dump_tree(const struct cmd_struct *cmd,
 		case GETOPT_VAL_BFS:
 			traverse = BTRFS_PRINT_TREE_BFS;
 			break;
+		case GETOPT_VAL_NOSCAN:
+			open_ctree_flags |= OPEN_CTREE_NO_DEVICES;
+			break;
 		default:
 			usage_unknown_option(cmd, argv);
 		}
 	}
 
-	if (check_argc_exact(argc - optind, 1))
+	if (check_argc_min(argc - optind, 1))
 		return 1;
 
-	ret = check_arg_type(argv[optind]);
-	if (ret != BTRFS_ARG_BLKDEV && ret != BTRFS_ARG_REG) {
+	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]);
+			}
+		}
+		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 < 0) {
 			errno = -ret;
-			error("invalid argument %s: %m", argv[optind]);
-		} else {
-			error("not a block device or regular file: %s",
-			      argv[optind]);
+			error("device scan %s: %m", argv[dev_optind]);
+			return ret;
 		}
-		goto out;
+		dev_optind++;
 	}
 
 	printf("%s\n", PACKAGE_STRING);