On 24.10.2018 07:31, Anand Jain wrote:
> This patch adds cli
> btrfs device forget [dev]
> to remove the given device structure in the kernel if the device
> is unmounted. If no argument is given it shall remove all stale
> (device which are not mounted) from the kernel.
>
> Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
> ---
> cmds-device.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++--------
> ioctl.h | 2 ++
> 2 files changed, 53 insertions(+), 8 deletions(-)
>
> diff --git a/cmds-device.c b/cmds-device.c
> index 2a05f70a76a9..c2a2b7f304b8 100644
> --- a/cmds-device.c
> +++ b/cmds-device.c
> @@ -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
> };
>
> @@ -267,32 +289,45 @@ 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) {
> + if (forget) {
> + ret = btrfs_forget_devices(NULL);
> + error_on(ret, "error %d while running forget", ret);
> + goto out;
> + }
nit: I would prefer to also have an if () {} else {} construct here,
similar to what you do below.
> printf("Scanning for Btrfs filesystems\n");
> ret = btrfs_scan_devices();
> error_on(ret, "error %d while scanning", ret);
> @@ -315,11 +350,19 @@ 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);
> }
> diff --git a/ioctl.h b/ioctl.h
> index 709e996f401c..e27d80e09392 100644
> --- a/ioctl.h
> +++ b/ioctl.h
> @@ -721,6 +721,8 @@ 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
>
