btrfs-progs: device scan: add new option to forget one or all scanned devices

This patch adds option --forget to 'device scan'

  $ btrfs device scan --forget [dev...]

to unregister the given device from kernel module. The device cannot be
part of a mounted filesystem, this will be reported as an error.

If no argument is given it will unregister all stale (device which are
not mounted) from the kernel.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Anand Jain 2019-01-04 13:31:52 +08:00 committed by David Sterba
parent 5c748404b9
commit dff3fb19d7
2 changed files with 61 additions and 13 deletions

View File

@ -254,10 +254,32 @@ static int cmd_device_delete(int argc, char **argv)
return _cmd_device_remove(argc, argv, cmd_device_delete_usage);
}
static int btrfs_forget_devices(char *path)
{
struct btrfs_ioctl_vol_args args;
int ret;
int fd;
fd = open("/dev/btrfs-control", O_RDWR);
if (fd < 0)
return -errno;
memset(&args, 0, sizeof(args));
if (path)
strncpy_null(args.name, path);
ret = ioctl(fd, BTRFS_IOC_FORGET_DEV, &args);
if (ret)
ret = -errno;
close(fd);
return ret;
}
static const char * const cmd_device_scan_usage[] = {
"btrfs device scan [(-d|--all-devices)|<device> [<device>...]]",
"Scan devices for a btrfs filesystem",
"btrfs device scan [(-d|--all-devices)|(-u|--forget)|<device> "\
"[<device>...]]",
"Scan or forget (deregister) devices for a btrfs filesystem",
" -d|--all-devices (deprecated)",
" -u|--forget [<device> ..]",
NULL
};
@ -267,37 +289,53 @@ static int cmd_device_scan(int argc, char **argv)
int devstart;
int all = 0;
int ret = 0;
int forget = 0;
optind = 0;
while (1) {
int c;
static const struct option long_options[] = {
{ "all-devices", no_argument, NULL, 'd'},
{ "forget", no_argument, NULL, 'u'},
{ NULL, 0, NULL, 0}
};
c = getopt_long(argc, argv, "d", long_options, NULL);
c = getopt_long(argc, argv, "du", long_options, NULL);
if (c < 0)
break;
switch (c) {
case 'd':
all = 1;
break;
case 'u':
forget = 1;
break;
default:
usage(cmd_device_scan_usage);
}
}
devstart = optind;
if (all && forget)
usage(cmd_device_scan_usage);
if (all && check_argc_max(argc - optind, 1))
usage(cmd_device_scan_usage);
if (all || argc - optind == 0) {
printf("Scanning for Btrfs filesystems\n");
ret = btrfs_scan_devices();
error_on(ret, "error %d while scanning", ret);
ret = btrfs_register_all_devices();
error_on(ret, "there are %d errors while registering devices", ret);
if (forget) {
ret = btrfs_forget_devices(NULL);
error_on(ret, "'%s', forget failed",
strerror(-ret));
} else {
printf("Scanning for Btrfs filesystems\n");
ret = btrfs_scan_devices();
error_on(ret, "error %d while scanning", ret);
ret = btrfs_register_all_devices();
error_on(ret,
"there are %d errors while registering devices",
ret);
}
goto out;
}
@ -315,11 +353,19 @@ static int cmd_device_scan(int argc, char **argv)
ret = 1;
goto out;
}
printf("Scanning for Btrfs filesystems in '%s'\n", path);
if (btrfs_register_one_device(path) != 0) {
ret = 1;
free(path);
goto out;
if (forget) {
ret = btrfs_forget_devices(path);
if (ret)
error("Can't forget '%s': %s",
path, strerror(-ret));
} else {
printf("Scanning for Btrfs filesystems in '%s'\n",
path);
if (btrfs_register_one_device(path) != 0) {
ret = 1;
free(path);
goto out;
}
}
free(path);
}

View File

@ -814,6 +814,8 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code)
struct btrfs_ioctl_vol_args)
#define BTRFS_IOC_SCAN_DEV _IOW(BTRFS_IOCTL_MAGIC, 4, \
struct btrfs_ioctl_vol_args)
#define BTRFS_IOC_FORGET_DEV _IOW(BTRFS_IOCTL_MAGIC, 5, \
struct btrfs_ioctl_vol_args)
/* trans start and trans end are dangerous, and only for
* use by applications that know how to avoid the
* resulting deadlocks