[PATCH] btrfs-progs: add a alloc-chunk command

[Josef Bacik <josef@toxicpanda.com>]

This is so we can force chunk allocation to test various parts of the
fs.  I used this to test my btrfsck patch for checking for empty block
groups, and a weird block group removal issue.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 cmds/filesystem.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
 ioctl.h           |  1 +
 2 files changed, 49 insertions(+)

diff --git a/cmds/filesystem.c b/cmds/filesystem.c
index 4f22089a..93d51195 100644
--- a/cmds/filesystem.c
+++ b/cmds/filesystem.c
@@ -1174,6 +1174,53 @@ static int cmd_filesystem_label(const struct cmd_struct *cmd,
 }
 static DEFINE_SIMPLE_COMMAND(filesystem_label, "label");
 
+static const char * const cmd_filesystem_alloc_chunk_usage[] = {
+	"btrfs filesystem alloc-chunk [data|metadata|system] <path>",
+	"Force a chunk allocation of the specified type on the given filesystem.",
+	NULL
+};
+
+static int cmd_filesystem_alloc_chunk(const struct cmd_struct *cmd,
+				      int argc, char **argv)
+{
+	char *path;
+	DIR *dirstream = NULL;
+	int fd, ret, e;
+	u64 flags = 0;
+
+	clean_args_no_options(cmd, argc, argv);
+
+	if (check_argc_exact(argc - optind, 2))
+		return 1;
+
+	if (!strncmp(argv[optind], "data", strlen("data")))
+		flags = BTRFS_BLOCK_GROUP_DATA;
+	else if (!strncmp(argv[optind], "system", strlen("system")))
+		flags = BTRFS_BLOCK_GROUP_SYSTEM;
+	else if (!strncmp(argv[optind], "metadata", strlen("metadata")))
+		flags = BTRFS_BLOCK_GROUP_METADATA;
+
+	if (flags == 0) {
+		error("Must specify either data, system, or metadata");
+		return 1;
+	}
+
+	path = argv[optind + 1];
+	fd = btrfs_open_dir(path, &dirstream, 1);
+	if (fd < 0)
+		return 1;
+
+	ret = ioctl(fd, BTRFS_IOC_ALLOC_CHUNK, &flags);
+	e = errno;
+	close_file_or_dir(fd, dirstream);
+	if (ret) {
+		error("Failed to alloc chunk: %d", e);
+		return 1;
+	}
+	return 0;
+}
+static DEFINE_SIMPLE_COMMAND(filesystem_alloc_chunk, "alloc-chunk");
+
 static const char * const cmd_filesystem_balance_usage[] = {
 	"btrfs filesystem balance [args...] (alias of \"btrfs balance\")",
 	"Please see \"btrfs balance --help\" for more information.",
@@ -1209,6 +1256,7 @@ static const struct cmd_group filesystem_cmd_group = {
 		&cmd_struct_filesystem_resize,
 		&cmd_struct_filesystem_label,
 		&cmd_struct_filesystem_usage,
+		&cmd_struct_filesystem_alloc_chunk,
 		NULL
 	}
 };
diff --git a/ioctl.h b/ioctl.h
index 66ee599f..4a5c2891 100644
--- a/ioctl.h
+++ b/ioctl.h
@@ -929,6 +929,7 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code)
 				struct btrfs_ioctl_get_subvol_rootref_args)
 #define BTRFS_IOC_INO_LOOKUP_USER _IOWR(BTRFS_IOCTL_MAGIC, 62, \
 				struct btrfs_ioctl_ino_lookup_user_args)
+#define BTRFS_IOC_ALLOC_CHUNK _IOR(BTRFS_IOCTL_MAGIC, 63, __u64)
 #ifdef __cplusplus
 }
 #endif
-- 
2.21.0