[PATCHv2,4/4] cmds: subvolume: Add --subvolid argument to subvol_delete
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Message ID 20200207131028.9977-5-marcos.souza.org@gmail.com
State New
Headers show
Series
  • btrfs-progs: Add BTRFS_IOC_SNAP_DESTROY_V2 support
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Commit Message

Marcos Paulo de Souza Feb. 7, 2020, 1:10 p.m. UTC
From: Marcos Paulo de Souza <mpdesouza@suse.com>

This can be used when a system has a file system mounted from a
subvolume, rather than the root file system, like below:

/
|- @subvol1
|- @subvol2
\- @subvol_default

If only @subvol_default is mounted, we have no path to reach
@subvol1 and @subvol2, thus no way to delete them.
This patch introduces a new argument to specify the subvolume id of the
subvolume/snapshot to be deleted.

If only @subvol_default is mounted, we have no path to reach
@subvol1 and @subvol2, thus no way to delete them. Current subvolume
delete ioctl takes a file handler point as argument, and if
@subvol_default is mounted, we can't reach @subvol1 and @subvol2 from
the same mount point.

This patch introduces a new flag to allow BTRFS_IOC_SNAP_DESTORY_V2
to delete subvolume using subvolid.

Now, we can use this new ioctl specifying the subvolume id and refer to
the same mount point. It's doesn't matter which subvolume was mounted,
since we can reach to the desired one using the subvolume id, and then
delete it.

Now "subvolume delete" receives a new argument --subvolid, which will
contain the subvolume the user wants to delete.

Fixes: #152
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
---
 Documentation/btrfs-subvolume.asciidoc        |  8 ++-
 cmds/subvolume.c                              | 53 ++++++++++++++++---
 tests/misc-tests/038-delete-subvolume/test.sh | 40 ++++++++++++++
 3 files changed, 94 insertions(+), 7 deletions(-)
 create mode 100755 tests/misc-tests/038-delete-subvolume/test.sh

Patch
diff mbox series

diff --git a/Documentation/btrfs-subvolume.asciidoc b/Documentation/btrfs-subvolume.asciidoc
index 6c0af2f8..9ebfcdfe 100644
--- a/Documentation/btrfs-subvolume.asciidoc
+++ b/Documentation/btrfs-subvolume.asciidoc
@@ -59,12 +59,15 @@  directory.
 Add the newly created subvolume to a qgroup. This option can be given multiple
 times.
 
-*delete* [options] <subvolume> [<subvolume>...]::
+*delete* [options] <[<subvolume> [<subvolume>...]] | [-s|--subvolid <subvolid> <path>]>::
 Delete the subvolume(s) from the filesystem.
 +
 If <subvolume> is not a subvolume, btrfs returns an error but continues if
 there are more arguments to process.
 +
+If --subvolid if used, <path> must point to a btrfs filesystem. See `btrfs
+subvolume list` how to get the subvolume id.
++
 The corresponding directory is removed instantly but the data blocks are
 removed later in the background. The command returns immediately. See `btrfs
 subvolume sync` how to wait until the subvolume gets completely removed.
@@ -84,6 +87,9 @@  wait for transaction commit after deleting each subvolume.
 +
 -v|--verbose::::
 verbose output of operations.
++
+-s|--subvolid::::
+subvolume id of the to be removed subvolume from <path>
 
 *find-new* <subvolume> <last_gen>::
 List the recently modified files in a subvolume, after <last_gen> generation.
diff --git a/cmds/subvolume.c b/cmds/subvolume.c
index 7a5fd79b..074fc11c 100644
--- a/cmds/subvolume.c
+++ b/cmds/subvolume.c
@@ -222,7 +222,8 @@  static int wait_for_commit(int fd)
 }
 
 static const char * const cmd_subvol_delete_usage[] = {
-	"btrfs subvolume delete [options] <subvolume> [<subvolume>...]",
+	"btrfs subvolume delete [options] <subvolume> [<subvolume>...]\n"
+	"btrfs subvolume delete [options] -s|--subvolid <subvolid> <path>",
 	"Delete subvolume(s)",
 	"Delete subvolumes from the filesystem. The corresponding directory",
 	"is removed instantly but the data blocks are removed later.",
@@ -234,6 +235,7 @@  static const char * const cmd_subvol_delete_usage[] = {
 	"-c|--commit-after      wait for transaction commit at the end of the operation",
 	"-C|--commit-each       wait for transaction commit after deleting each subvolume",
 	"-v|--verbose           verbose output of operations",
+	"-s|--subvolid          subvolume id of the to be removed subvolume",
 	NULL
 };
 
@@ -246,12 +248,14 @@  static int cmd_subvol_delete(const struct cmd_struct *cmd,
 	char	*dname, *vname, *cpath;
 	char	*dupdname = NULL;
 	char	*dupvname = NULL;
-	char	*path;
+	char	*path = NULL;
 	DIR	*dirstream = NULL;
 	int verbose = 0;
 	int commit_mode = 0;
 	u8 fsid[BTRFS_FSID_SIZE];
+	u64 subvolid = 0;
 	char uuidbuf[BTRFS_UUID_UNPARSED_SIZE];
+	char full_volpath[BTRFS_SUBVOL_NAME_MAX];
 	struct seen_fsid *seen_fsid_hash[SEEN_FSID_HASH_SIZE] = { NULL, };
 	enum { COMMIT_AFTER = 1, COMMIT_EACH = 2 };
 	enum btrfs_util_error err;
@@ -262,11 +266,12 @@  static int cmd_subvol_delete(const struct cmd_struct *cmd,
 		static const struct option long_options[] = {
 			{"commit-after", no_argument, NULL, 'c'},
 			{"commit-each", no_argument, NULL, 'C'},
+			{"subvolid", required_argument, NULL, 's'},
 			{"verbose", no_argument, NULL, 'v'},
 			{NULL, 0, NULL, 0}
 		};
 
-		c = getopt_long(argc, argv, "cCv", long_options, NULL);
+		c = getopt_long(argc, argv, "cCvs:", long_options, NULL);
 		if (c < 0)
 			break;
 
@@ -280,6 +285,9 @@  static int cmd_subvol_delete(const struct cmd_struct *cmd,
 		case 'v':
 			verbose++;
 			break;
+		case 's':
+			subvolid = arg_strtou64(optarg);
+			break;
 		default:
 			usage_unknown_option(cmd, argv);
 		}
@@ -288,6 +296,10 @@  static int cmd_subvol_delete(const struct cmd_struct *cmd,
 	if (check_argc_min(argc - optind, 1))
 		return 1;
 
+	/* when using --subvolid, ensure that we have only one argument */
+	if (subvolid > 0 && check_argc_exact(argc - optind, 1))
+		return 1;
+
 	if (verbose > 0) {
 		printf("Transaction commit: %s\n",
 			!commit_mode ? "none (default)" :
@@ -296,6 +308,23 @@  static int cmd_subvol_delete(const struct cmd_struct *cmd,
 
 	cnt = optind;
 
+	/* check the following syntax: subvolume delete --subvolid <subvolid> <path> */
+	if (subvolid > 0) {
+		char *subvol;
+
+		path = argv[cnt];
+		err = btrfs_util_subvolume_path(path, subvolid, &subvol);
+		if (err) {
+			error_btrfs_util(err);
+			ret = 1;
+			goto out;
+		}
+
+		/* build new volpath using the volume name found */
+		sprintf(full_volpath, "%s/%s", path, subvol);
+		free(subvol);
+	}
+
 again:
 	path = argv[cnt];
 
@@ -318,17 +347,29 @@  again:
 	vname = basename(dupvname);
 	free(cpath);
 
+	/* when subvolid is passed, <path> will point to the mount point */
+	if (subvolid > 0)
+		dname = dupvname;
+
 	fd = btrfs_open_dir(dname, &dirstream, 1);
 	if (fd < 0) {
 		ret = 1;
 		goto out;
 	}
 
-	printf("Delete subvolume (%s): '%s/%s'\n",
+	printf("Delete subvolume (%s): ",
 		commit_mode == COMMIT_EACH || (commit_mode == COMMIT_AFTER && cnt + 1 == argc)
-		? "commit" : "no-commit", dname, vname);
+		? "commit" : "no-commit");
+
+	if (subvolid == 0)
+		printf("'%s/%s'\n", dname, vname);
+	else
+		printf("'%s'\n", full_volpath);
 
-	err = btrfs_util_delete_subvolume_fd(fd, vname, 0);
+	if (subvolid == 0)
+		err = btrfs_util_delete_subvolume_fd(fd, vname, 0);
+	else
+		err = btrfs_util_delete_subvolume_by_id_fd(fd, subvolid);
 	if (err) {
 		error_btrfs_util(err);
 		ret = 1;
diff --git a/tests/misc-tests/038-delete-subvolume/test.sh b/tests/misc-tests/038-delete-subvolume/test.sh
new file mode 100755
index 00000000..d81ae120
--- /dev/null
+++ b/tests/misc-tests/038-delete-subvolume/test.sh
@@ -0,0 +1,40 @@ 
+#!/bin/bash
+# test btrfs subvolume delete --subvolid <volid> <path>
+
+source "$TEST_TOP/common"
+
+check_prereq mkfs.btrfs
+check_prereq btrfs
+
+setup_root_helper
+prepare_test_dev
+
+run_check_mkfs_test_dev
+run_check_mount_test_dev
+
+run_check $SUDO_HELPER "$TOP/btrfs" subvolume create "$TEST_MNT"/mysubvol1
+run_check $SUDO_HELPER "$TOP/btrfs" subvolume create "$TEST_MNT"/mysubvol2
+run_check $SUDO_HELPER "$TOP/btrfs" subvolume create "$TEST_MNT"/mysubvol3
+
+# subvolid expected failures
+run_mustfail "subvolume delete --subvolid expects an integer" \
+	$SUDO_HELPER "$TOP/btrfs" subvolume delete --subvolid aaa "$TEST_MNT"
+
+run_mustfail "subvolume delete --subvolid with invalid unexisting subvolume" \
+	$SUDO_HELPER "$TOP/btrfs" subvolume delete --subvolid 999 "$TEST_MNT"
+
+run_mustfail "subvolume delete --subvolid expects only one extra argument: the mountpoint" \
+	$SUDO_HELPER "$TOP/btrfs" subvolume delete --subvolid 256 "$TEST_MNT" "$TEST_MNT"
+
+# delete the recently created subvol using the subvolid
+run_check $SUDO_HELPER "$TOP/btrfs" subvolume delete --subvolid 256 "$TEST_MNT"
+
+run_check_umount_test_dev
+
+run_check_mount_test_dev -o subvol=mysubvol2
+# when mounted the subvolume mysubvol3, mysubvol2 is not reachable by the
+# current mount point, but "subvolume delete --subvolid " should be able to
+# delete it
+run_check $SUDO_HELPER "$TOP/btrfs" subvolume delete --subvolid 258 "$TEST_MNT"
+
+run_check_umount_test_dev