On Tue, Dec 05, 2017 at 04:52:57PM +0800, Anand Jain wrote:
> This patch adds
> btrfs device ignode <dev>
> so that a device can be ignored/missed during mount if the device is
> already been scanned. Basically, this command will undo the effect
> of the command
> btrfs device scan <dev>
As it logicall belongs to scan, I'd rather make it an option, like
$ btrfs scan --unregister
or
$ btrfs scan --forget
The meaning of 'ignore' in this context is not clear to me, we can
ignore errors on the device.
> This change is compatible with older kernel without the ioctl
> BTRFS_IOC_IGNORE_DEV which is added here. At which it shall
> report 'Inappropriate ioctl for device'. And will report
> 'Operation not permitted' on mounted device.
>
> Signed-off-by: Anand Jain <anand.j...@oracle.com>
> ---
> v1-4: No change.
>
> cmds-device.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> ioctl.h | 2 ++
> 2 files changed, 56 insertions(+)
>
> diff --git a/cmds-device.c b/cmds-device.c
> index f4cdb39f64ac..31b1945d3339 100644
> --- a/cmds-device.c
> +++ b/cmds-device.c
> @@ -329,6 +329,59 @@ out:
> return !!ret;
> }
>
> +static const char * const cmd_device_ignore_usage[] = {
> + "btrfs device ignore [<device>]",
> + "Ignore a device in the btrfs kernel module.",
> + NULL
> +};
> +
> +static int btrfs_ignore_one_device(char *path)
> +{
> + struct btrfs_ioctl_vol_args args;
> + int fd;
> + int ret;
> +
> + fd = open("/dev/btrfs-control", O_RDWR);
> + if (fd < 0)
> + return -errno;
> +
> + memset(&args, 0, sizeof(args));
> + strncpy_null(args.name, path);
> + ret = ioctl(fd, BTRFS_IOC_IGNORE_DEV, &args);
> + if (ret)
> + ret = -errno;
> + close(fd);
> + return ret;
> +}
> +
> +static int cmd_device_ignore(int argc, char **argv)
> +{
> + int ret = 0;
> + char *path;
> +
> + if (check_argc_max(argc - optind, 1))
> + usage(cmd_device_ignore_usage);
> +
> + if (is_block_device(argv[1]) != 1) {
> + error("Not a block device: %s", argv[1]);
> + return -ENOENT;
> + }
> +
> + path = canonicalize_path(argv[1]);
> + if (!path) {
> + error("Could not canonicalize path '%s': %s",
> + argv[1], strerror(errno));
> + return -ENOENT;
> + }
> +
> + ret = btrfs_ignore_one_device(path);
> + if (ret)
> + error("Can't ignore %s: %s", path, strerror(-ret));
> +
> + free(path);
> + return ret;
> +}
> +
> static const char * const cmd_device_ready_usage[] = {
> "btrfs device ready <device>",
> "Check device to see if it has all of its devices in cache for
> mounting",
> @@ -604,6 +657,7 @@ const struct cmd_group device_cmd_group = {
> CMD_ALIAS },
> { "remove", cmd_device_remove, cmd_device_remove_usage, NULL, 0
> },
> { "scan", cmd_device_scan, cmd_device_scan_usage, NULL, 0 },
> + { "ignore", cmd_device_ignore, cmd_device_ignore_usage, NULL, 0
> },
> { "ready", cmd_device_ready, cmd_device_ready_usage, NULL, 0 },
> { "stats", cmd_device_stats, cmd_device_stats_usage, NULL, 0 },
> { "usage", cmd_device_usage,
> diff --git a/ioctl.h b/ioctl.h
> index 709e996f401c..bef8508119aa 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_IGNORE_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
> --
> 2.7.0
>
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