btrfs: switch to btrfs_create_{clone,snapshot}()

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

diff --git a/src/lxc/bdev/bdev.c b/src/lxc/bdev/bdev.c
index 5ae3ba65764147206936a702ae57d4cc009cc255..9d8c0172bc742ec3100d795b5cc829a778758f59 100644 (file)
--- a/src/lxc/bdev/bdev.c
+++ b/src/lxc/bdev/bdev.c
@@ -96,8 +96,8 @@ static const struct bdev_ops btrfs_ops = {
     .clone_paths = &btrfs_clonepaths,
     .destroy = &btrfs_destroy,
     .create = &btrfs_create,
-    .create_clone = NULL,
-    .create_snapshot = NULL,
+    .create_clone = &btrfs_create_clone,
+    .create_snapshot = &btrfs_create_snapshot,
     .can_snapshot = true,
     .can_backup = true,
 };
@@ -415,6 +415,8 @@ struct bdev *bdev_copy(struct lxc_container *c0, const char *cname,
                bdevtype = "dir";
        else if (!bdevtype)
                bdevtype = orig->type;
+
+       /* get new bdev type */
        new = bdev_get(bdevtype);
        if (!new) {
                ERROR("no such block device type: %s",
@@ -424,17 +426,24 @@ 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;
-
+       /* create new paths */
        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);
                goto err;
        }
 
-       /* If the storage driver is "btrfs" then the we will create snapshot. */
+       if (!strcmp(orig->type, "btrfs") && !strcmp(new->type, "btrfs")) {
+               bool bret = false;
+               if (snap || btrfs_same_fs(orig->dest, new->dest) == 0)
+                       bret = new->ops->create_snapshot(c0->lxc_conf, orig, new);
+               else
+                       bret = new->ops->create_clone(c0->lxc_conf, orig, new, 0);
+               if (!bret)
+                       return NULL;
+               return new;
+       }
+
        if (strcmp(bdevtype, "btrfs")) {
                if (!strcmp(new->type, "overlay") ||
                    !strcmp(new->type, "overlayfs"))

diff --git a/src/lxc/bdev/lxcbtrfs.c b/src/lxc/bdev/lxcbtrfs.c
index b8a317afb5adb30819e6b2d68bd7f12ffbf8e9d7..0a9cf913361073a6ba4c73a8c2cea7d5a2c7909d 100644 (file)
--- a/src/lxc/bdev/lxcbtrfs.c
+++ b/src/lxc/bdev/lxcbtrfs.c
@@ -375,7 +375,6 @@ int btrfs_clonepaths(struct bdev *orig, struct bdev *new, const char *oldname,
                     const char *lxcpath, int snap, uint64_t newsize,
                     struct lxc_conf *conf)
 {
-       int ret;
        char *src;
 
        if (!orig->dest || !orig->src)
@@ -396,7 +395,7 @@ int btrfs_clonepaths(struct bdev *orig, struct bdev *new, const char *oldname,
                ERROR("Failed to create new rootfs path");
                return -1;
        }
-       TRACE("Created new rootfs path \"%s\"", new->src);
+       TRACE("Constructed new rootfs path \"%s\"", new->src);
 
        src = lxc_storage_get_path(new->src, "btrfs");
        new->dest = strdup(src);
@@ -414,39 +413,95 @@ int btrfs_clonepaths(struct bdev *orig, struct bdev *new, const char *oldname,
                }
        }
 
-       if (snap) {
-               struct rsync_data_char sdata;
-               if (!am_unpriv()) {
-                       ret = btrfs_snapshot(orig->dest, new->dest);
-                       if (ret < 0) {
-                               SYSERROR("Failed to create btrfs snapshot "
-                                        "\"%s\" from \"%s\"",
-                                        new->dest, orig->dest);
-                               return -1;
-                       }
-                       TRACE("Created btrfs snapshot \"%s\" from \"%s\"",
-                             new->dest, orig->dest);
-                       return 0;
-               }
+       return 0;
+}
 
-               sdata.dest = new->dest;
-               sdata.src = orig->dest;
-               return userns_exec_1(conf, btrfs_snapshot_wrapper, &sdata,
-                                    "btrfs_snapshot_wrapper");
-       }
+bool btrfs_create_clone(struct lxc_conf *conf, struct bdev *orig,
+                       struct bdev *new, uint64_t newsize)
+{
+       int pid, ret;
+       struct rsync_data data;
 
        ret = rmdir(new->dest);
-       if (ret < 0 && errno != ENOENT) {
-               SYSERROR("Failed to remove directory \"%s\"", new->dest);
-               return -1;
-       }
+       if (ret < 0 && errno != ENOENT)
+               return false;
 
        ret = btrfs_subvolume_create(new->dest);
-       if (ret < 0)
+       if (ret < 0) {
                SYSERROR("Failed to create btrfs subvolume \"%s\"", new->dest);
+               return false;
+       }
+
+       /* rsync contents */
+       pid = fork();
+       if (pid < 0) {
+               SYSERROR("fork");
+               return false;
+       }
+
+       if (pid > 0) {
+               int ret = wait_for_pid(pid);
+               bdev_put(orig);
+               if (ret < 0) {
+                       bdev_put(new);
+                       return false;
+               }
+               return true;
+       }
+
+       data.orig = orig;
+       data.new = new;
+
+       if (am_unpriv())
+               ret = userns_exec_1(conf, rsync_rootfs_wrapper, &data,
+                                   "rsync_rootfs_wrapper");
        else
-               TRACE("Created btrfs subvolume \"%s\"", new->dest);
-       return ret;
+               ret = rsync_rootfs(&data);
+       if (ret < 0) {
+               ERROR("Failed to rsync");
+               return false;
+       }
+
+       TRACE("Created btrfs subvolume \"%s\"", new->dest);
+       return true;
+}
+
+bool btrfs_create_snapshot(struct lxc_conf *conf, struct bdev *orig,
+                          struct bdev *new)
+{
+       int ret;
+
+       ret = rmdir(new->dest);
+       if (ret < 0 && errno != ENOENT)
+               return false;
+
+       if (am_unpriv()) {
+               struct rsync_data_char args;
+
+               args.src = orig->dest;
+               args.dest = new->dest;
+
+               ret = userns_exec_1(conf, btrfs_snapshot_wrapper, &args,
+                               "btrfs_snapshot_wrapper");
+               if (ret < 0) {
+                       ERROR("Failed to run \"btrfs_snapshot_wrapper\"");
+                       return false;
+               }
+
+               TRACE("Created btrfs snapshot \"%s\" from \"%s\"", new->dest,
+                     orig->dest);
+               return true;
+       }
+
+       ret = btrfs_snapshot(orig->dest, new->dest);
+       if (ret < 0) {
+               SYSERROR("Failed to create btrfs snapshot \"%s\" from \"%s\"",
+                        new->dest, orig->dest);
+               return false;
+       }
+
+       TRACE("Created btrfs snapshot \"%s\" from \"%s\"", new->dest, orig->dest);
+       return true;
 }
 
 static int btrfs_do_destroy_subvol(const char *path)

diff --git a/src/lxc/bdev/lxcbtrfs.h b/src/lxc/bdev/lxcbtrfs.h
index b2ebb373971fa60c9ca860674ecd589c9b544dd6..13b48399405bec5e01dfeda959584ef3c1721bdd 100644 (file)
--- a/src/lxc/bdev/lxcbtrfs.h
+++ b/src/lxc/bdev/lxcbtrfs.h
@@ -413,5 +413,9 @@ bool btrfs_try_remove_subvol(const char *path);
 int btrfs_same_fs(const char *orig, const char *new);
 int btrfs_snapshot(const char *orig, const char *new);
 int btrfs_snapshot_wrapper(void *data);
+bool btrfs_create_clone(struct lxc_conf *conf, struct bdev *orig,
+                       struct bdev *new, uint64_t newsize);
+bool btrfs_create_snapshot(struct lxc_conf *conf, struct bdev *orig,
+                          struct bdev *new);
 
 #endif // __LXC_BTRFS_H