2 files changed, 52 insertions, 3 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index e54b5e50c927..9a71fec86152 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -55,6 +55,7 @@
 #include "backref.h"
 #include "rcu-string.h"
 #include "send.h"
+#include "dev-replace.h"
 
 /* Mask out flags that are inappropriate for the given type of inode. */
 static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
@@ -3171,6 +3172,51 @@ static long btrfs_ioctl_get_dev_stats(struct btrfs_root *root,
         return ret;
 }
 
+static long btrfs_ioctl_dev_replace(struct btrfs_root *root, void __user *arg)
+{
+        struct btrfs_ioctl_dev_replace_args *p;
+        int ret;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        p = memdup_user(arg, sizeof(*p));
+        if (IS_ERR(p))
+                return PTR_ERR(p);
+
+        switch (p->cmd) {
+        case BTRFS_IOCTL_DEV_REPLACE_CMD_START:
+                if (atomic_xchg(
+                        &root->fs_info->mutually_exclusive_operation_running,
+                        1)) {
+                        pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");
+                        ret = -EINPROGRESS;
+                } else {
+                        ret = btrfs_dev_replace_start(root, p);
+                        atomic_set(
+                         &root->fs_info->mutually_exclusive_operation_running,
+                         0);
+                }
+                break;
+        case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
+                btrfs_dev_replace_status(root->fs_info, p);
+                ret = 0;
+                break;
+        case BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL:
+                ret = btrfs_dev_replace_cancel(root->fs_info, p);
+                break;
+        default:
+                ret = -EINVAL;
+                break;
+        }
+
+        if (copy_to_user(arg, p, sizeof(*p)))
+                ret = -EFAULT;
+
+        kfree(p);
+        return ret;
+}
+
 static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
 {
         int ret = 0;
@@ -3826,6 +3872,8 @@ long btrfs_ioctl(struct file *file, unsigned int
                 return btrfs_ioctl_qgroup_create(root, argp);
         case BTRFS_IOC_QGROUP_LIMIT:
                 return btrfs_ioctl_qgroup_limit(root, argp);
+        case BTRFS_IOC_DEV_REPLACE:
+                return btrfs_ioctl_dev_replace(root, argp);
         }
 
         return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 62006ba02719..dabca9cc8c2e 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -30,6 +30,8 @@ struct btrfs_ioctl_vol_args {
         char name[BTRFS_PATH_NAME_MAX + 1];
 };
 
+#define BTRFS_DEVICE_PATH_NAME_MAX 1024
+
 #define BTRFS_SUBVOL_CREATE_ASYNC       (1ULL << 0)
 #define BTRFS_SUBVOL_RDONLY             (1ULL << 1)
 #define BTRFS_SUBVOL_QGROUP_INHERIT     (1ULL << 2)
@@ -127,10 +129,10 @@ struct btrfs_ioctl_scrub_args {
 #define BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID     1
 struct btrfs_ioctl_dev_replace_start_params {
         __u64 srcdevid; /* in, if 0, use srcdev_name instead */
-        __u8 srcdev_name[BTRFS_PATH_NAME_MAX + 1];      /* in */
-        __u8 tgtdev_name[BTRFS_PATH_NAME_MAX + 1];      /* in */
         __u64 cont_reading_from_srcdev_mode;    /* in, see #define
                                                  * above */
+        __u8 srcdev_name[BTRFS_DEVICE_PATH_NAME_MAX + 1];       /* in */
+        __u8 tgtdev_name[BTRFS_DEVICE_PATH_NAME_MAX + 1];       /* in */
 };
 
 #define BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED     0
@@ -165,7 +167,6 @@ struct btrfs_ioctl_dev_replace_args {
         __u64 spare[64];
 };
 
-#define BTRFS_DEVICE_PATH_NAME_MAX 1024
 struct btrfs_ioctl_dev_info_args {
         __u64 devid;                            /* in/out */
         __u8 uuid[BTRFS_UUID_SIZE];             /* in/out */