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-rw-r--r--fs/btrfs/send.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 1e9caa552235..12363081f53b 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -6593,6 +6593,38 @@ commit_trans:
return btrfs_commit_transaction(trans);
}
+/*
+ * Make sure any existing dellaloc is flushed for any root used by a send
+ * operation so that we do not miss any data and we do not race with writeback
+ * finishing and changing a tree while send is using the tree. This could
+ * happen if a subvolume is in RW mode, has delalloc, is turned to RO mode and
+ * a send operation then uses the subvolume.
+ * After flushing delalloc ensure_commit_roots_uptodate() must be called.
+ */
+static int flush_delalloc_roots(struct send_ctx *sctx)
+{
+ struct btrfs_root *root = sctx->parent_root;
+ int ret;
+ int i;
+
+ if (root) {
+ ret = btrfs_start_delalloc_snapshot(root);
+ if (ret)
+ return ret;
+ btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX);
+ }
+
+ for (i = 0; i < sctx->clone_roots_cnt; i++) {
+ root = sctx->clone_roots[i].root;
+ ret = btrfs_start_delalloc_snapshot(root);
+ if (ret)
+ return ret;
+ btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX);
+ }
+
+ return 0;
+}
+
static void btrfs_root_dec_send_in_progress(struct btrfs_root* root)
{
spin_lock(&root->root_item_lock);
@@ -6817,6 +6849,10 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
NULL);
sort_clone_roots = 1;
+ ret = flush_delalloc_roots(sctx);
+ if (ret)
+ goto out;
+
ret = ensure_commit_roots_uptodate(sctx);
if (ret)
goto out;