[PATCH v2] btrfs-progs: receive: cannot find clone source subvol when receiving in reverse direction

[Arsenii Skvortsov <ettavolt@gmail.com>]

process_clone only searches the received_uuid, but could exist in an earlier
uuid that isn't the received_uuid.  Mirror what process_snapshot does and search
both the received_uuid and if that fails look up by normal uuid.

Fixes: https://github.com/kdave/btrfs-progs/issues/606

Signed-off-by: Arsenii Skvortsov <ettavolt@gmail.com>
---
 cmds/receive.c                               | 28 +++---
 tests/misc-tests/058-reverse-receive/test.sh | 98 ++++++++++++++++++++
 2 files changed, 115 insertions(+), 11 deletions(-)
 create mode 100755 tests/misc-tests/058-reverse-receive/test.sh

diff --git a/cmds/receive.c b/cmds/receive.c
index d16dc0a..763c2af 100644
--- a/cmds/receive.c
+++ b/cmds/receive.c
@@ -222,6 +222,19 @@ out:
 	return ret;
 }
 
+static struct subvol_info *search_source_subvol(struct subvol_uuid_search *s,
+			const u8 *subvol_uuid, u64 transid)
+{
+	struct subvol_info *found;
+	found = subvol_uuid_search(s, 0, subvol_uuid, transid, NULL,
+			subvol_search_by_received_uuid);
+	if (IS_ERR_OR_NULL(found)) {
+		found = subvol_uuid_search(s, 0, subvol_uuid, transid, NULL,
+				subvol_search_by_uuid);
+	}
+	return found;
+}
+
 static int process_snapshot(const char *path, const u8 *uuid, u64 ctransid,
 			    const u8 *parent_uuid, u64 parent_ctransid,
 			    void *user)
@@ -284,14 +297,8 @@ static int process_snapshot(const char *path, const u8 *uuid, u64 ctransid,
 	memset(&args_v2, 0, sizeof(args_v2));
 	strncpy_null(args_v2.name, path);
 
-	parent_subvol = subvol_uuid_search(rctx->mnt_fd, 0, parent_uuid,
-					   parent_ctransid, NULL,
-					   subvol_search_by_received_uuid);
-	if (IS_ERR_OR_NULL(parent_subvol)) {
-		parent_subvol = subvol_uuid_search(rctx->mnt_fd, 0, parent_uuid,
-						   parent_ctransid, NULL,
-						   subvol_search_by_uuid);
-	}
+	parent_subvol = search_source_subvol(rctx->mnt_fd, parent_uuid,
+			parent_ctransid);
 	if (IS_ERR_OR_NULL(parent_subvol)) {
 		if (!parent_subvol)
 			ret = -ENOENT;
@@ -746,9 +753,8 @@ static int process_clone(const char *path, u64 offset, u64 len,
 		   BTRFS_UUID_SIZE) == 0) {
 		subvol_path = rctx->cur_subvol_path;
 	} else {
-		si = subvol_uuid_search(rctx->mnt_fd, 0, clone_uuid, clone_ctransid,
-					NULL,
-					subvol_search_by_received_uuid);
+		si = search_source_subvol(rctx->mnt_fd, clone_uuid,
+				clone_ctransid);
 		if (IS_ERR_OR_NULL(si)) {
 			char uuid_str[BTRFS_UUID_UNPARSED_SIZE];
 
diff --git a/tests/misc-tests/058-reverse-receive/test.sh b/tests/misc-tests/058-reverse-receive/test.sh
new file mode 100755
index 0000000..6eff560
--- /dev/null
+++ b/tests/misc-tests/058-reverse-receive/test.sh
@@ -0,0 +1,98 @@
+#!/bin/bash
+#
+# Receive in reverse direction must not throw an error if it can find an earlier "sent" parent.
+# In general, shows a backup+sync setup between two (or more) PCs with an external drive.
+
+source "$TEST_TOP/common"
+
+check_prereq mkfs.btrfs
+check_prereq btrfs
+check_global_prereq dd
+
+declare -a roots
+i_pc1=1
+# An external drive used to backup and carry profile.
+i_ext=2
+i_pc2=3
+roots[$i_pc1]="$TEST_MNT/pc1"
+roots[$i_ext]="$TEST_MNT/external"
+roots[$i_pc2]="$TEST_MNT/pc2"
+
+setup_root_helper
+mkdir -p ${roots[@]}
+setup_loopdevs 3
+prepare_loopdevs
+for i in `seq 3`; do
+	TEST_DEV=${loopdevs[$i]}
+    TEST_MNT="${roots[$i]}"
+    run_check_mkfs_test_dev
+    run_check_mount_test_dev
+    run_check $SUDO_HELPER mkdir -p "$TEST_MNT/.snapshots"
+done
+
+run_check_update_file()
+{
+    run_check $SUDO_HELPER cp --reflink ${roots[$1]}/profile/$2 ${roots[$1]}/profile/staging
+    run_check $SUDO_HELPER dd if=/dev/urandom conv=notrunc bs=4K count=4 oseek=$3 "of=${roots[$1]}/profile/staging"
+    run_check $SUDO_HELPER mv ${roots[$1]}/profile/staging ${roots[$1]}/profile/$2
+}
+run_check_copy_snapshot_with_diff()
+{
+    _mktemp_local send.data
+    run_check $SUDO_HELPER "$TOP/btrfs" send -f send.data -p "${roots[$1]}/.snapshots/$2" "${roots[$1]}/.snapshots/$3"
+    run_check $SUDO_HELPER "$TOP/btrfs" receive -f send.data "${roots[$4]}/.snapshots"
+}
+run_check_backup_profile()
+{
+    run_check $SUDO_HELPER "$TOP/btrfs" subvolume snapshot -r "${roots[$1]}/profile" "${roots[$1]}/.snapshots/$3"
+    run_check_copy_snapshot_with_diff $1 $2 $3 $i_ext
+    # Don't keep old snapshot in pc
+    run_check $SUDO_HELPER "$TOP/btrfs" subvolume delete "${roots[$1]}/.snapshots/$2"
+}
+run_check_restore_profile()
+{
+    run_check $SUDO_HELPER "$TOP/btrfs" subvolume snapshot "${roots[$1]}/.snapshots/$2" "${roots[$1]}/profile"
+}
+run_check_copy_fresh_backup_and_replace_profile()
+{
+    run_check_copy_snapshot_with_diff $i_ext $2 $3 $1
+    # IRL, it would be a nice idea to make a backup snapshot before deleting.
+    run_check $SUDO_HELPER "$TOP/btrfs" subvolume delete "${roots[$1]}/profile"
+    run_check_restore_profile $1 $3
+    # Don't keep old snapshot in pc
+    run_check $SUDO_HELPER "$TOP/btrfs" subvolume delete "${roots[$1]}/.snapshots/$2"
+}
+
+
+run_check $SUDO_HELPER "$TOP/btrfs" subvolume create "${roots[$i_pc1]}/profile"
+run_check $SUDO_HELPER dd if=/dev/urandom bs=4K count=16 "of=${roots[$i_pc1]}/profile/day1"
+run_check $SUDO_HELPER "$TOP/btrfs" subvolume snapshot -r "${roots[$i_pc1]}/profile" "${roots[$i_pc1]}/.snapshots/day1"
+_mktemp_local send.data
+run_check $SUDO_HELPER "$TOP/btrfs" send -f send.data "${roots[$i_pc1]}/.snapshots/day1"
+run_check $SUDO_HELPER "$TOP/btrfs" receive -f send.data "${roots[$i_ext]}/.snapshots"
+
+run_check_update_file $i_pc1 day1 2
+run_check_backup_profile $i_pc1 day1 day2
+
+_mktemp_local send.data
+run_check $SUDO_HELPER "$TOP/btrfs" send -f send.data "${roots[$i_ext]}/.snapshots/day2"
+run_check $SUDO_HELPER "$TOP/btrfs" receive -f send.data "${roots[$i_pc2]}/.snapshots"
+run_check_restore_profile $i_pc2 day2
+run_check_update_file $i_pc2 day1 3
+run_check_backup_profile $i_pc2 day2 day3
+
+run_check_update_file $i_pc2 day1 4
+run_check_backup_profile $i_pc2 day3 day4
+
+run_check_copy_fresh_backup_and_replace_profile $i_pc1 day2 day4
+run_check_update_file $i_pc1 day1 5
+run_check_backup_profile $i_pc1 day4 day5
+
+run_check_copy_fresh_backup_and_replace_profile $i_pc2 day4 day5
+run_check_update_file $i_pc2 day1 6
+run_check_backup_profile $i_pc2 day5 day6
+
+run_check_umount_test_dev ${loopdevs[@]}
+rmdir ${roots[@]}
+rm -f send.data
+cleanup_loopdevs
-- 
2.41.0