- added some btrfs util functions

aschnell · Apr 16, 2024 · 73c1ba2 · 73c1ba2
1 parent 7ddd236
commit 73c1ba2
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Showing 3 changed files with 71 additions and 10 deletions.
diff --git a/snapper/BtrfsUtils.cc b/snapper/BtrfsUtils.cc
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) [2011-2015] Novell, Inc.
- * Copyright (c) [2016-2023] SUSE LLC
+ * Copyright (c) [2016-2024] SUSE LLC
  *
  * All Rights Reserved.
  *
@@ -204,6 +204,8 @@ namespace snapper
 
 #endif
 
+	    // no read-only nor qgroup handling below
+
 	    struct btrfs_ioctl_vol_args args;
 	    memset(&args, 0, sizeof(args));
 
@@ -599,16 +601,18 @@ namespace snapper
 
 	struct TreeSearchOpts
 	{
-	    TreeSearchOpts(__u32 type) : min_offset(0), max_offset(-1), min_type(type), max_type(type) {}
+	    TreeSearchOpts(__u32 type) : min_type(type), max_type(type) {}
 
-	    __u64 min_offset;
-	    __u64 max_offset;
+	    __u64 min_offset = 0;
+	    __u64 max_offset = -1;
 
 	    __u32 min_type;
 	    __u32 max_type;
 
 	    std::function<void(const struct btrfs_ioctl_search_args& args,
-			       const struct btrfs_ioctl_search_header& sh)> callback;
+			       const struct btrfs_ioctl_search_header& sh)> callback =
+		[](const struct btrfs_ioctl_search_args& args,
+		   const struct btrfs_ioctl_search_header& sh){};
 	};
 
 
@@ -679,6 +683,24 @@ namespace snapper
 	}
 
 
+	bool
+	does_qgroup_exist(int fd, qgroup_t qgroup)
+	{
+	    TreeSearchOpts tree_search_opts(BTRFS_QGROUP_INFO_KEY);
+	    tree_search_opts.min_offset = tree_search_opts.max_offset = qgroup;
+
+	    try
+	    {
+		return qgroups_tree_search(fd, tree_search_opts) > 0;
+	    }
+	    catch (const std::runtime_error& e)
+	    {
+		// happens when quota is disabled
+		return false;
+	    }
+	}
+
+
 	qgroup_t
 	qgroup_find_free(int fd, uint64_t level)
 	{
@@ -711,12 +733,12 @@ namespace snapper
 
 
 	vector<qgroup_t>
-	qgroup_query_children(int fd, qgroup_t parent)
+	qgroup_query_relations(int fd, qgroup_t qgroup)
 	{
 	    vector<qgroup_t> ret;
 
 	    TreeSearchOpts tree_search_opts(BTRFS_QGROUP_RELATION_KEY);
-	    tree_search_opts.min_offset = tree_search_opts.max_offset = parent;
+	    tree_search_opts.min_offset = tree_search_opts.max_offset = qgroup;
 	    tree_search_opts.callback = [&ret](const struct btrfs_ioctl_search_args& args,
 					       const struct btrfs_ioctl_search_header& sh)
 	    {
@@ -729,6 +751,25 @@ namespace snapper
 	}
 
 
+	vector<qgroup_t>
+	qgroup_query_children(int fd, qgroup_t parent)
+	{
+	    uint64_t level = get_level(parent);
+	    if (level == 0)
+		return {};
+
+	    --level;
+
+	    vector<qgroup_t> ret = qgroup_query_relations(fd, parent);
+
+	    ret.erase(remove_if(ret.begin(), ret.end(),
+		[level](qgroup_t qgroup){ return level != get_level(qgroup); }
+	    ), ret.end());
+
+	    return ret;
+	}
+
+
 	QGroupUsage
 	qgroup_query_usage(int fd, qgroup_t qgroup)
 	{

diff --git a/snapper/BtrfsUtils.h b/snapper/BtrfsUtils.h
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) [2011-2015] Novell, Inc.
- * Copyright (c) [2016-2023] SUSE LLC
+ * Copyright (c) [2016-2024] SUSE LLC
  *
  * All Rights Reserved.
  *
@@ -81,8 +81,10 @@ namespace snapper
 	void qgroup_assign(int fd, qgroup_t src, qgroup_t dst);
 	void qgroup_remove(int fd, qgroup_t src, qgroup_t dst);
 
+	bool does_qgroup_exist(int fd, qgroup_t qgroup);
 	qgroup_t qgroup_find_free(int fd, uint64_t level);
 
+	vector<qgroup_t> qgroup_query_relations(int fd, qgroup_t qgroup);
 	vector<qgroup_t> qgroup_query_children(int fd, qgroup_t parent);
 
 	struct QGroupUsage

diff --git a/testsuite-real/test-btrfsutils.cc b/testsuite-real/test-btrfsutils.cc
@@ -7,9 +7,9 @@
  */
 
 
-#include <errno.h>
+#include <cerrno>
 #include <fcntl.h>
-#include <string.h>
+#include <cstring>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ -59,6 +59,12 @@ main()
     }
 
 
+    if (false)
+    {
+	cout << does_qgroup_exist(fd, parse_qgroup("1/0")) << '\n';
+    }
+
+
     if (false)
     {
 	qgroup_create(fd, parse_qgroup("1/0"));
@@ -105,6 +111,17 @@ main()
     }
 
 
+    if (false)
+    {
+	cout << "qgroup_query_relations" << endl;
+
+	vector<qgroup_t> relations = qgroup_query_relations(fd, parse_qgroup("1/0"));
+	for (qgroup_t relation : relations)
+	    cout << format_qgroup(relation) << " ";
+	cout << endl;
+    }
+
+
     if (false)
     {
 	cout << "qgroup_query_children" << endl;
@@ -115,5 +132,6 @@ main()
 	cout << endl;
     }
 
+
     close(fd);
 }