The shutdown interface should all follow the XFS one, which use magic
'X', and ioctl number 125, with a u32 as flags.
For now btrfs doesn't follow the flags, as there is no traditional
journal in btrfs (the log tree is to mostly speed up fsync).
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
fs/btrfs/ioctl.c | 18 ++++++++++++++++++
include/uapi/linux/btrfs.h | 9 +++++++++
2 files changed, 27 insertions(+)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 84a516053a8e..1fd7486af851 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -5213,6 +5213,16 @@ static int btrfs_ioctl_subvol_sync(struct btrfs_fs_info *fs_info, void __user *a
return 0;
}
+static int btrfs_emergency_shutdown(struct btrfs_fs_info *fs_info, u32 flags)
+{
+ if (flags >= BTRFS_SHUTDOWN_FLAGS_LAST)
+ return -EINVAL;
+
+ /* For now, btrfs do not distinguish the different flags. */
+ btrfs_shutdown(fs_info);
+ return 0;
+}
+
long btrfs_ioctl(struct file *file, unsigned int
cmd, unsigned long arg)
{
@@ -5368,6 +5378,14 @@ long btrfs_ioctl(struct file *file, unsigned int
#endif
case BTRFS_IOC_SUBVOL_SYNC_WAIT:
return btrfs_ioctl_subvol_sync(fs_info, argp);
+ case BTRFS_IOC_SHUTDOWN:
+ u32 flags;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ if (get_user(flags, (__u32 __user *)arg))
+ return -EFAULT;
+ return btrfs_emergency_shutdown(fs_info, flags);
}
return -ENOTTY;
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index dd02160015b2..8f6324cf15d9 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -1096,6 +1096,12 @@ enum btrfs_err_code {
BTRFS_ERROR_DEV_RAID1C4_MIN_NOT_MET,
};
+/* Flags for IOC_SHUTDOWN, should match XFS' flags. */
+#define BTRFS_SHUTDOWN_FLAGS_DEFAULT 0x0
+#define BTRFS_SHUTDOWN_FLAGS_LOGFLUSH 0x1
+#define BTRFS_SHUTDOWN_FLAGS_NOLOGFLUSH 0x2
+#define BTRFS_SHUTDOWN_FLAGS_LAST 0x3
+
#define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
struct btrfs_ioctl_vol_args)
#define BTRFS_IOC_DEFRAG _IOW(BTRFS_IOCTL_MAGIC, 2, \
@@ -1217,6 +1223,9 @@ enum btrfs_err_code {
#define BTRFS_IOC_SUBVOL_SYNC_WAIT _IOW(BTRFS_IOCTL_MAGIC, 65, \
struct btrfs_ioctl_subvol_wait)
+/* Shutdown ioctl should follow XFS's interfaces, thus not using btrfs magic. */
+#define BTRFS_IOC_SHUTDOWN _IOR('X', 125, __u32)
+
#ifdef __cplusplus
}
#endif
--
2.49.0
