[Libguestfs] [PATCH] New API: btrfs_replace_start

[Pino Tsao]

Signed-off-by: Pino Tsao <caoj.fnst at cn.fujitsu.com>
---
 daemon/btrfs.c                    | 40 +++++++++++++++++++++++++++++++++++++++
 generator/actions.ml              | 19 +++++++++++++++++++
 tests/btrfs/test-btrfs-devices.sh |  8 ++++++++
 3 files changed, 67 insertions(+)

diff --git a/daemon/btrfs.c b/daemon/btrfs.c
index 39392f7..acc300d 100644
--- a/daemon/btrfs.c
+++ b/daemon/btrfs.c
@@ -2083,3 +2083,43 @@ do_btrfs_image (char *const *sources, const char *image,
 
   return 0;
 }
+
+int
+do_btrfs_replace_start (const char *srcdev, const char *targetdev,
+                        const char* mntpoint, int force)
+{
+  const size_t MAX_ARGS = 64;
+  const char *argv[MAX_ARGS];
+  size_t i = 0;
+  CLEANUP_FREE char *err = NULL;
+  CLEANUP_FREE char *path_buf = NULL;
+  int r;
+
+  path_buf = sysroot_path (mntpoint);
+  if (path_buf == NULL) {
+    reply_with_perror ("malloc");
+    return -1;
+  }
+
+  ADD_ARG (argv, i, str_btrfs);
+  ADD_ARG (argv, i, "replace");
+  ADD_ARG (argv, i, "start");
+  ADD_ARG (argv, i, srcdev);
+  ADD_ARG (argv, i, targetdev);
+  ADD_ARG (argv, i, path_buf);
+  ADD_ARG (argv, i, "-B");
+
+  if ((optargs_bitmask & GUESTFS_BTRFS_REPLACE_START_FORCE_BITMASK) && force)
+    ADD_ARG (argv, i, "-f");
+
+  ADD_ARG (argv, i, NULL);
+
+  r = commandv (NULL, &err, argv);
+  if (r == -1) {
+    reply_with_error ("%s: %s", mntpoint, err);
+    return -1;
+  }
+
+  return 0;
+}
+
diff --git a/generator/actions.ml b/generator/actions.ml
index 1a89869..4443600 100644
--- a/generator/actions.ml
+++ b/generator/actions.ml
@@ -12579,6 +12579,25 @@ numbered C<partnum> on device C<device>.
 
 It returns C<primary>, C<logical>, or C<extended>." };
 
+  { defaults with
+    name = "btrfs_replace_start"; added = (1, 29, 46);
+    style = RErr, [Device "srcdev"; Device "targetdev"; Pathname "mntpoint"], [OBool "force"];
+    proc_nr = Some 455;
+    optional = Some "btrfs"; camel_name = "BTRFSReplaceStart";
+    test_excuse = "It is better to have 3+ test disk to do the test, so put the test in 'tests/btrfs' directory";
+    shortdesc = "replace a btrfs managed device with another device";
+    longdesc = "\
+Replace device of a btrfs filesystem. On a live filesystem, duplicate the data
+to the target device which is currently stored on the source device.
+After completion of the operation, the source device is wiped out and
+removed from the filesystem.
+
+The <targetdev> needs to be same size or larger than the <srcdev>. Devices
+which are currently mounted are never allowed to be used as the <targetdev>
+
+Option 'force=true' means using and overwriting <targetdev> even if
+it looks like containing a valid btrfs filesystem." };
+
 ]
 
 (* Non-API meta-commands available only in guestfish.
diff --git a/tests/btrfs/test-btrfs-devices.sh b/tests/btrfs/test-btrfs-devices.sh
index 3935c60..463b0a8 100755
--- a/tests/btrfs/test-btrfs-devices.sh
+++ b/tests/btrfs/test-btrfs-devices.sh
@@ -66,6 +66,8 @@ btrfs-device-add "/dev/sdc1 /dev/sdd1" /
 btrfs-device-delete "/dev/sdb1" /
 btrfs-device-add "/dev/sdb1" /
 btrfs-device-delete "/dev/sdc1 /dev/sdd1" /
+btrfs-replace-start "/dev/sda1" "/dev/sdd1" / force:true
+btrfs-replace-start "/dev/sdd1" "/dev/sda1" / force:true
 
 mkdir /data2
 tar-in $srcdir/../data/filesanddirs-10M.tar.xz /data2 compress:xz
@@ -74,6 +76,8 @@ btrfs-device-add "/dev/sdc1 /dev/sdd1" /
 btrfs-device-delete "/dev/sdb1" /
 btrfs-device-add "/dev/sdb1" /
 btrfs-device-delete "/dev/sdc1 /dev/sdd1" /
+btrfs-replace-start "/dev/sda1" "/dev/sdd1" / force:true
+btrfs-replace-start "/dev/sdd1" "/dev/sda1" / force:true
 
 mkdir /data3
 tar-in $srcdir/../data/filesanddirs-10M.tar.xz /data3 compress:xz
@@ -82,6 +86,8 @@ btrfs-device-add "/dev/sdc1 /dev/sdd1" /
 btrfs-device-delete "/dev/sdb1" /
 btrfs-device-add "/dev/sdb1" /
 btrfs-device-delete "/dev/sdc1 /dev/sdd1" /
+btrfs-replace-start "/dev/sda1" "/dev/sdd1" / force:true
+btrfs-replace-start "/dev/sdd1" "/dev/sda1" / force:true
 
 mkdir /data4
 tar-in $srcdir/../data/filesanddirs-10M.tar.xz /data4 compress:xz
@@ -90,6 +96,8 @@ btrfs-device-add "/dev/sdc1 /dev/sdd1" /
 btrfs-device-delete "/dev/sdb1" /
 btrfs-device-add "/dev/sdb1" /
 btrfs-device-delete "/dev/sdc1 /dev/sdd1" /
+btrfs-replace-start "/dev/sda1" "/dev/sdd1" / force:true
+btrfs-replace-start "/dev/sdd1" "/dev/sda1" / force:true
 
 EOF
 
-- 
2.1.0