| Message ID | 1373866257-10519-7-git-send-email-anand.jain@oracle.com (mailing list archive) |
|---|---|
| State | Under Review, archived |
| Headers | show |
On Mon, Jul 15, 2013 at 01:30:52PM +0800, Anand Jain wrote: > This patch adds --mapper option to btrfs device scan and > btrfs filesystem show cli, when used will look for btrfs > devs under /dev/mapper and will use the links provided > under the /dev/mapper. > In the long run I want the usage of /dev/mapper path > (along with /proc/partitions) be the default option to > scan for the btrfs devs. (/proc/partitions must be scanned > as well because to include the mapper blacklisted devs.) Well, we want to avoid using own scanning and always consult the blkid cache, so I'd rather stop adding user-visible changes to this command. david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 06/08/2013 01:04, David Sterba wrote: > On Mon, Jul 15, 2013 at 01:30:52PM +0800, Anand Jain wrote: >> This patch adds --mapper option to btrfs device scan and >> btrfs filesystem show cli, when used will look for btrfs >> devs under /dev/mapper and will use the links provided >> under the /dev/mapper. > >> In the long run I want the usage of /dev/mapper path >> (along with /proc/partitions) be the default option to >> scan for the btrfs devs. (/proc/partitions must be scanned >> as well because to include the mapper blacklisted devs.) > > Well, we want to avoid using own scanning and always consult the blkid > cache, so I'd rather stop adding user-visible changes to this command. here is a test prog "t" (attached inline below) using blkid. t picks up both non multipath path and mapper path as below. ---- # ./t Device: /dev/sdb b03095dc-8eb5-40c9-8790-da6977110799 Device: /dev/sdc abc347f2-dfcc-46bf-a4ac-e21fba7ff1a3 Device: /dev/mapper/mpatha b03095dc-8eb5-40c9-8790-da6977110799 Device: /dev/mapper/mpathb abc347f2-dfcc-46bf-a4ac-e21fba7ff1a3 Found 4 ------ However when /etc/multipath.conf defaults { user_friendly_names no } then the mapper paths are not friendly enough to use ------- # ./t Device: /dev/sdb b03095dc-8eb5-40c9-8790-da6977110799 Device: /dev/sdc abc347f2-dfcc-46bf-a4ac-e21fba7ff1a3 Device: /dev/mapper/1ATA VBOX HARDDISK VB96b6139c-83f38bf1 b03095dc-8eb5-40c9-8790-da6977110799 Device: /dev/mapper/1ATA VBOX HARDDISK VBc6ab3781-f63da170 abc347f2-dfcc-46bf-a4ac-e21fba7ff1a3 Found 4 ------ in this case the /dev/dm-<n> would have been better to use. and our own scan does the better job here.. as it reads /proc/partition and gives priority to dm-<n> paths ------ btrfs fi show Label: none uuid: abc347f2-dfcc-46bf-a4ac-e21fba7ff1a3 Total devices 1 FS bytes used 28.00KiB devid 1 size 2.00GiB used 240.75MiB path /dev/dm-1 Label: none uuid: b03095dc-8eb5-40c9-8790-da6977110799 Total devices 1 FS bytes used 28.00KiB devid 1 size 1.98GiB used 238.25MiB path /dev/dm-0 ------- so as of now having our scan is better than blkid. Now for the users who want to use the user friendly name provided by mapper. the newly introduced option --mapper which just looks under /dev/mapper will help. Thanks, Anand ----------------t.c-------------- #include <stdio.h> #include <blkid/blkid.h> #include <stdlib.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include <string.h> main() { char *type; char str[100]; int total = 0; blkid_dev_iterate iter = NULL; blkid_dev dev = NULL; blkid_cache cache = NULL; memset(str, '0', 100); if (blkid_get_cache(&cache, 0) < 0) return -1; blkid_probe_all(cache); iter = blkid_dev_iterate_begin(cache); //blkid_dev_set_search(iter, NULL, NULL); blkid_dev_set_search(iter, "TYPE", "btrfs"); while (blkid_dev_next(iter, &dev) == 0) { dev = blkid_verify(cache, dev); if (!dev) continue; else { total++; printf("Device: %s\t%s\n", blkid_dev_devname(dev), blkid_get_tag_value(cache,"UUID", blkid_dev_devname(dev))); } } blkid_dev_iterate_end(iter); printf("Found %d\n", total); return total; } -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/cmds-device.c b/cmds-device.c index 59edcb9..abf1360 100644 --- a/cmds-device.c +++ b/cmds-device.c @@ -178,7 +178,7 @@ static int cmd_rm_dev(int argc, char **argv) } static const char * const cmd_scan_dev_usage[] = { - "btrfs device scan [<--all-devices>|<device> [<device>...]]", + "btrfs device scan [<--all-devices>|<--mapper>|<device> [<device>...]]", "Scan devices for a btrfs filesystem", NULL }; @@ -195,6 +195,12 @@ static int cmd_scan_dev(int argc, char **argv) where = BTRFS_SCAN_DEV; devstart += 1; + } else if( argc > 1 && !strcmp(argv[1],"--mapper")){ + if (check_argc_max(argc, 2)) + usage(cmd_scan_dev_usage); + + where = BTRFS_SCAN_MAPPER; + devstart += 1; } if(argc<=devstart){ diff --git a/cmds-filesystem.c b/cmds-filesystem.c index 6ef6e6b..0f5a30a 100644 --- a/cmds-filesystem.c +++ b/cmds-filesystem.c @@ -223,7 +223,7 @@ static void print_one_uuid(struct btrfs_fs_devices *fs_devices) } static const char * const cmd_show_usage[] = { - "btrfs filesystem show [--all-devices|<uuid>]", + "btrfs filesystem show [--all-devices|--mapper|<uuid>]", "Show the structure of a filesystem", "If no argument is given, structure of all present filesystems is shown.", NULL @@ -239,9 +239,12 @@ static int cmd_show(int argc, char **argv) int where = BTRFS_SCAN_PROC; int searchstart = 1; - if( argc > 1 && !strcmp(argv[1],"--all-devices")){ + if (argc > 1 && !strcmp(argv[1],"--all-devices")) { where = BTRFS_SCAN_DEV; searchstart += 1; + } else if (argc > 1 && !strcmp(argv[1],"--mapper")) { + where = BTRFS_SCAN_MAPPER; + searchstart += 1; } if (check_argc_max(argc, searchstart + 1)) diff --git a/man/btrfs.8.in b/man/btrfs.8.in index bc94579..eebf87d 100644 --- a/man/btrfs.8.in +++ b/man/btrfs.8.in @@ -31,11 +31,11 @@ btrfs \- control a btrfs filesystem .PP \fBbtrfs\fP \fBfilesystem label\fP\fI <dev> [newlabel]\fP .PP -\fBbtrfs\fP \fBfilesystem show\fP\fI [--all-devices|<uuid>]\fP +\fBbtrfs\fP \fBfilesystem show\fP\fI [--all-devices|--mapper|<uuid>]\fP .PP \fBbtrfs\fP \fBfilesystem balance\fP\fI <path> \fP .PP -\fBbtrfs\fP \fBdevice scan\fP\fI [--all-devices|<device> [<device>...]]\fP +\fBbtrfs\fP \fBdevice scan\fP\fI [--all-devices|--mapper|<device> [<device>...]]\fP .PP \fBbtrfs\fP \fBdevice stats\fP [-z] {\fI<path>\fP|\fI<device>\fP} .PP @@ -273,10 +273,11 @@ following constraints exist for a label: .IP - the maximum allowable length shall be less than 256 chars -\fBfilesystem show\fR [--all-devices|<uuid>]\fR +\fBfilesystem show\fR [--all-devices|--mapper|<uuid>]\fR Show the btrfs filesystem with some additional info. If no \fIUUID\fP is passed, \fBbtrfs\fR show info of all the btrfs filesystem. If \fB--all-devices\fP is passed, all the devices under /dev are scanned; +If \fB--mapper\fP is passed, all the devices under /dev/mapper are scanned; otherwise the devices list is extracted from the /proc/partitions file. .TP @@ -305,10 +306,10 @@ Add device(s) to the filesystem identified by \fI<path>\fR. Remove device(s) from a filesystem identified by \fI<path>\fR. .TP -\fBdevice scan\fR \fI[--all-devices|<device> [<device>...]\fR +\fBdevice scan\fR \fI[--all-devices|--mapper|<device> [<device>...]\fR If one or more devices are passed, these are scanned for a btrfs filesystem. If no devices are passed, \fBbtrfs\fR scans all the block devices listed -in the /proc/partitions file. +If \fB--mapper\fP is passed, all the devices under /dev/mapper are scanned. Finally, if \fB--all-devices\fP is passed, all the devices under /dev are scanned. .TP diff --git a/utils.c b/utils.c index 59010c9..a7f2ca3 100644 --- a/utils.c +++ b/utils.c @@ -1849,6 +1849,9 @@ int scan_for_btrfs(int where, int update_kernel) case BTRFS_SCAN_DEV: ret = btrfs_scan_one_dir("/dev", update_kernel); break; + case BTRFS_SCAN_MAPPER: + ret = btrfs_scan_one_dir("/dev/mapper", update_kernel); + break; } return ret; } diff --git a/utils.h b/utils.h index bdfa76b..a10c51a 100644 --- a/utils.h +++ b/utils.h @@ -24,8 +24,9 @@ #define BTRFS_MKFS_SYSTEM_GROUP_SIZE (4 * 1024 * 1024) -#define BTRFS_SCAN_PROC 1 -#define BTRFS_SCAN_DEV 2 +#define BTRFS_SCAN_PROC 1 +#define BTRFS_SCAN_DEV 2 +#define BTRFS_SCAN_MAPPER 3 int make_btrfs(int fd, const char *device, const char *label, u64 blocks[6], u64 num_bytes, u32 nodesize,
Currently, btrsf fi show and btrfs dev scan uses /proc/partitions (by default) (which gives priority to dm-<x> over sd<y> paths) and with --all-devices it will scan /dev only (where it skips links under /dev/mapper). However using /dev/mapper paths are in common practice with mount, fstab, and lvm, so its better to be consistent with them. This patch adds --mapper option to btrfs device scan and btrfs filesystem show cli, when used will look for btrfs devs under /dev/mapper and will use the links provided under the /dev/mapper. eg: btrfs fi show --mapper Label: none uuid: 0a621111-ad84-4d80-842a-dd9c1c60bf51 Total devices 2 FS bytes used 1.17MB devid 1 size 44.99GB used 2.04GB path /dev/mapper/mpathe devid 2 size 48.23GB used 2.03GB path /dev/mapper/mpathd Label: none uuid: bad9105f-bdc6-4626-9ba7-80bd97aebe19 Total devices 1 FS bytes used 28.00KB devid 1 size 15.00GB used 2.04GB path /dev/mapper/mpathbp1 In the long run I want the usage of /dev/mapper path (along with /proc/partitions) be the default option to scan for the btrfs devs. (/proc/partitions must be scanned as well because to include the mapper blacklisted devs.) Signed-off-by: Anand Jain <anand.jain@oracle.com> --- cmds-device.c | 8 +++++++- cmds-filesystem.c | 7 +++++-- man/btrfs.8.in | 11 ++++++----- utils.c | 3 +++ utils.h | 5 +++-- 5 files changed, 24 insertions(+), 10 deletions(-)