[PATCH] btrfs-progs: add recursive subvol delete

[Mark Harmstone <maharmstone@fb.com>]

From: Omar Sandoval <osandov@fb.com>

Adds a --recursive option to btrfs subvol delete, causing it to pass the
BTRFS_UTIL_DELETE_SUBVOLUME_RECURSIVE flag through to libbtrfsutil.

This is a resubmission of part of a patch that Omar Sandoval sent in
2018, which appears to have been overlooked:
https://lore.kernel.org/linux-btrfs/e42cdc5d5287269faf4d09e8c9786d0b3adeb658.1516991902.git.osandov@fb.com/

Signed-off-by: Mark Harmstone <maharmstone@meta.com>
Co-authored-by: Mark Harmstone <maharmstone@meta.com>
---
 Documentation/btrfs-subvolume.rst |  4 ++++
 cmds/subvolume.c                  | 15 +++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/Documentation/btrfs-subvolume.rst b/Documentation/btrfs-subvolume.rst
index d1e89f15..b1f22344 100644
--- a/Documentation/btrfs-subvolume.rst
+++ b/Documentation/btrfs-subvolume.rst
@@ -112,6 +112,10 @@ delete [options] [<subvolume> [<subvolume>...]], delete -i|--subvolid <subvolid>
         -i|--subvolid <subvolid>
                 subvolume id to be removed instead of the <path> that should point to the
                 filesystem with the subvolume
+
+        -R|--recursive
+                delete subvolumes beneath each subvolume recursively
+
         -v|--verbose
                 (deprecated) alias for global *-v* option
 
diff --git a/cmds/subvolume.c b/cmds/subvolume.c
index 52bc8850..b4151af2 100644
--- a/cmds/subvolume.c
+++ b/cmds/subvolume.c
@@ -347,6 +347,7 @@ static const char * const cmd_subvolume_delete_usage[] = {
 	OPTLINE("-c|--commit-after", "wait for transaction commit at the end of the operation"),
 	OPTLINE("-C|--commit-each", "wait for transaction commit after deleting each subvolume"),
 	OPTLINE("-i|--subvolid", "subvolume id of the to be removed subvolume"),
+	OPTLINE("-R|--recursive", "delete subvolumes beneath each subvolume recursively"),
 	OPTLINE("-v|--verbose", "deprecated, alias for global -v option"),
 	HELPINFO_INSERT_GLOBALS,
 	HELPINFO_INSERT_VERBOSE,
@@ -367,6 +368,7 @@ static int cmd_subvolume_delete(const struct cmd_struct *cmd, int argc, char **a
 	char	*path = NULL;
 	int commit_mode = 0;
 	bool subvol_path_not_found = false;
+	int flags = 0;
 	u8 fsid[BTRFS_FSID_SIZE];
 	u64 subvolid = 0;
 	char uuidbuf[BTRFS_UUID_UNPARSED_SIZE];
@@ -383,11 +385,12 @@ static int cmd_subvolume_delete(const struct cmd_struct *cmd, int argc, char **a
 			{"commit-after", no_argument, NULL, 'c'},
 			{"commit-each", no_argument, NULL, 'C'},
 			{"subvolid", required_argument, NULL, 'i'},
+			{"recursive", no_argument, NULL, 'R'},
 			{"verbose", no_argument, NULL, 'v'},
 			{NULL, 0, NULL, 0}
 		};
 
-		c = getopt_long(argc, argv, "cCi:v", long_options, NULL);
+		c = getopt_long(argc, argv, "cCi:Rv", long_options, NULL);
 		if (c < 0)
 			break;
 
@@ -401,6 +404,9 @@ static int cmd_subvolume_delete(const struct cmd_struct *cmd, int argc, char **a
 		case 'i':
 			subvolid = arg_strtou64(optarg);
 			break;
+		case 'R':
+			flags |= BTRFS_UTIL_DELETE_SUBVOLUME_RECURSIVE;
+			break;
 		case 'v':
 			bconf_be_verbose();
 			break;
@@ -416,6 +422,11 @@ static int cmd_subvolume_delete(const struct cmd_struct *cmd, int argc, char **a
 	if (subvolid > 0 && check_argc_exact(argc - optind, 1))
 		return 1;
 
+	if (subvolid > 0 && flags & BTRFS_UTIL_DELETE_SUBVOLUME_RECURSIVE) {
+		error("option --recursive not supported with --subvolid");
+		return 1;
+	}
+
 	pr_verbose(LOG_INFO, "Transaction commit: %s\n",
 		   !commit_mode ? "none (default)" :
 		   commit_mode == COMMIT_AFTER ? "at the end" : "after each");
@@ -528,7 +539,7 @@ again:
 
 	/* Start deleting. */
 	if (subvolid == 0)
-		err = btrfs_util_delete_subvolume_fd(fd, vname, 0);
+		err = btrfs_util_delete_subvolume_fd(fd, vname, flags);
 	else
 		err = btrfs_util_delete_subvolume_by_id_fd(fd, subvolid);
 	if (err) {
-- 
2.44.2