1 files changed, 46 insertions, 4 deletions

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 614da0d44d56..68da757615ae 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -85,6 +85,7 @@ struct send_ctx {
         u32 send_max_size;
         u64 total_send_size;
         u64 cmd_send_size[BTRFS_SEND_C_MAX + 1];
+        u64 flags;      /* 'flags' member of btrfs_ioctl_send_args is u64 */
 
         struct vfsmount *mnt;
 
@@ -3709,6 +3710,39 @@ out:
         return ret;
 }
 
+/*
+ * Send an update extent command to user space.
+ */
+static int send_update_extent(struct send_ctx *sctx,
+                              u64 offset, u32 len)
+{
+        int ret = 0;
+        struct fs_path *p;
+
+        p = fs_path_alloc(sctx);
+        if (!p)
+                return -ENOMEM;
+
+        ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT);
+        if (ret < 0)
+                goto out;
+
+        ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+        if (ret < 0)
+                goto out;
+
+        TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+        TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
+        TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len);
+
+        ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+        fs_path_free(sctx, p);
+        return ret;
+}
+
 static int send_write_or_clone(struct send_ctx *sctx,
                                struct btrfs_path *path,
                                struct btrfs_key *key,
@@ -3744,7 +3778,11 @@ static int send_write_or_clone(struct send_ctx *sctx,
                 goto out;
         }
 
-        if (!clone_root) {
+        if (clone_root) {
+                ret = send_clone(sctx, offset, len, clone_root);
+        } else if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) {
+                ret = send_update_extent(sctx, offset, len);
+        } else {
                 while (pos < len) {
                         l = len - pos;
                         if (l > BTRFS_SEND_READ_SIZE)
@@ -3757,10 +3795,7 @@ static int send_write_or_clone(struct send_ctx *sctx,
                         pos += ret;
                 }
                 ret = 0;
-        } else {
-                ret = send_clone(sctx, offset, len, clone_root);
         }
-
 out:
         return ret;
 }
@@ -4560,6 +4595,11 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
                 goto out;
         }
 
+        if (arg->flags & ~BTRFS_SEND_FLAG_NO_FILE_DATA) {
+                ret = -EINVAL;
+                goto out;
+        }
+
         sctx = kzalloc(sizeof(struct send_ctx), GFP_NOFS);
         if (!sctx) {
                 ret = -ENOMEM;
@@ -4571,6 +4611,8 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_)
         INIT_RADIX_TREE(&sctx->name_cache, GFP_NOFS);
         INIT_LIST_HEAD(&sctx->name_cache_list);
 
+        sctx->flags = arg->flags;
+
         sctx->send_filp = fget(arg->send_fd);
         if (IS_ERR(sctx->send_filp)) {
                 ret = PTR_ERR(sctx->send_filp);