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author | Anand Jain <anand.jain@oracle.com> | 2019-01-04 13:31:54 +0800 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2019-02-25 14:13:30 +0100 |
commit | 228a73abde5c04428678e917b271f8526cfd90ed (patch) | |
tree | 1fb860dafe17f8408eaefc7e232779d8da713c00 /include/uapi | |
parent | 034f784d7cab9af731ccd41b34e5e9625ef47db7 (diff) | |
download | linux-228a73abde5c04428678e917b271f8526cfd90ed.tar.bz2 |
btrfs: introduce new ioctl to unregister a btrfs device
Support for a new command that can be used eg. as a command
$ btrfs device scan --forget [dev]'
(the final name may change though)
to undo the effects of 'btrfs device scan [dev]'. For this purpose
this patch proposes to use ioctl #5 as it was empty and is next to the
SCAN ioctl.
The new ioctl BTRFS_IOC_FORGET_DEV works only on the control device
(/dev/btrfs-control) to unregister one or all devices, devices that are
not mounted.
The argument is struct btrfs_ioctl_vol_args, ::name specifies the device
path. To unregister all device, the path is an empty string.
Again, the devices are removed only if they aren't part of a mounte
filesystem.
This new ioctl provides:
- release of unwanted btrfs_fs_devices and btrfs_devices structures
from memory if the device is not going to be mounted
- ability to mount filesystem in degraded mode, when one devices is
corrupted like in split brain raid1
- running test cases which would require reloading the kernel module
but this is not possible eg. due to mounted filesystem or built-in
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'include/uapi')
-rw-r--r-- | include/uapi/linux/btrfs.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index e0763bc4158e..c195896d478f 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -837,6 +837,8 @@ enum btrfs_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 |