From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Tue, 15 Aug 2017 16:12:31 +0000 (+0200)
Subject: Revert "btrfs: simplify"
X-Git-Tag: lxc-2.0.9~98^2~21
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=97788c7295f8602f8c6d847899cae118a439075e;p=thirdparty%2Flxc.git

Revert "btrfs: simplify"

This reverts commit 36c55bf31c67d5048b6dd7f85ac425f3b2e22fd3.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---

diff --git a/src/lxc/bdev/bdev.c b/src/lxc/bdev/bdev.c
index a99a05177..34d8e78d2 100644
--- a/src/lxc/bdev/bdev.c
+++ b/src/lxc/bdev/bdev.c
@@ -406,10 +406,6 @@ struct bdev *bdev_copy(struct lxc_container *c0, const char *cname,
 	}
 	TRACE("Detected \"%s\" storage driver", new->type);
 
-	if (bdevtype && !strcmp(orig->type, "btrfs") &&
-	    !strcmp(new->type, "btrfs"))
-		snap = 1;
-
 	if (new->ops->clone_paths(orig, new, oldname, cname, oldpath, lxcpath,
 				  snap, newsize, c0->lxc_conf) < 0) {
 		ERROR("Failed getting pathnames for clone of \"%s\"", src);
@@ -431,6 +427,36 @@ struct bdev *bdev_copy(struct lxc_container *c0, const char *cname,
 	if (snap)
 		return new;
 
+	/* https://github.com/lxc/lxc/issues/131
+	 * Use btrfs snapshot feature instead of rsync to restore if both orig
+	 * and new are btrfs.
+	 */
+	if (bdevtype && strcmp(orig->type, "btrfs") == 0 &&
+	    strcmp(new->type, "btrfs") == 0 &&
+	    btrfs_same_fs(orig->dest, new->dest) == 0) {
+		struct rsync_data_char arg;
+
+		if (btrfs_destroy(new) < 0) {
+			ERROR("Failed to destroy \"%s\" btrfs subvolume", new->dest);
+			goto err;
+		}
+
+		arg.src = orig->dest;
+		arg.dest = new->dest;
+		if (am_unpriv())
+			ret = userns_exec_1(c0->lxc_conf, btrfs_snapshot_wrapper,
+					  &arg, "btrfs_snapshot_wrapper");
+		else
+			ret = btrfs_snapshot(orig->dest, new->dest);
+		if (ret < 0) {
+			SYSERROR("Failed to create btrfs snapshot \"%s\" of \"%s\"",
+			         new->dest, orig->dest);
+			goto err;
+		}
+		bdev_put(orig);
+		return new;
+	}
+
 	pid = fork();
 	if (pid < 0) {
 		SYSERROR("fork");