cmd_show_super: Look up and print names of member devices

bch2_sb_to_text_with_names(): print device paths and models of each
member.

Fixes: https://github.com/koverstreet/bcachefs/issues/801
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bch_bindgen/build.rs

@@ -85,6 +85,7 @@ fn main() {
         .opaque_type("gc_stripe")
         .opaque_type("open_bucket.*")
         .opaque_type("replicas_delta_list")
+        .allowlist_type("sb_names")
         .no_copy("btree_trans")
         .no_copy("printbuf")
         .no_partialeq("bkey")

bch_bindgen/src/libbcachefs_wrapper.h

@@ -13,6 +13,7 @@
 #include "include/linux/blkdev.h"
 #include "cmds.h"
 #include "raid/raid.h"
+#include "src/rust_to_c.h"
 
 /* Fix753 is a workaround for https://github.com/rust-lang/rust-bindgen/issues/753
  * Functional macro are not expanded with bindgen, e.g. ioctl are automatically ignored

c_src/cmd_format.c

@@ -21,6 +21,7 @@
 #include <uuid/uuid.h>
 
 #include "cmds.h"
+#include "cmd_super.h"
 #include "tools-util.h"
 #include "posix_to_bcachefs.h"
 #include "libbcachefs.h"
@@ -293,7 +294,7 @@ int cmd_format(int argc, char *argv[])
 		struct printbuf buf = PRINTBUF;
 		buf.human_readable_units = true;
 
-		bch2_sb_to_text(&buf, sb, false, 1 << BCH_SB_FIELD_members_v2);
+		bch2_sb_to_text_with_names(&buf, sb, false, 1 << BCH_SB_FIELD_members_v2, -1);
 		printf("%s", buf.buf);
 		printbuf_exit(&buf);
 	}

c_src/cmd_super.c

@@ -21,6 +21,7 @@
 #include <uuid/uuid.h>
 
 #include "cmds.h"
+#include "cmd_super.h"
 #include "libbcachefs.h"
 #include "libbcachefs/opts.h"
 #include "libbcachefs/super-io.h"
@@ -28,6 +29,8 @@
 
 #include "libbcachefs/darray.h"
 
+#include "src/rust_to_c.h"
+
 static void show_super_usage(void)
 {
 	puts("bcachefs show-super \n"
@@ -42,6 +45,72 @@ static void show_super_usage(void)
 	exit(EXIT_SUCCESS);
 }
 
+static struct sb_name *sb_dev_to_name(sb_names sb_names, unsigned idx)
+{
+	darray_for_each(sb_names, i)
+		if (i->sb.sb->dev_idx == idx)
+			return i;
+	return NULL;
+}
+
+static void print_one_member(struct printbuf *out, sb_names sb_names,
+			     struct bch_sb *sb,
+			     struct bch_sb_field_disk_groups *gi,
+			     struct bch_member m, unsigned idx)
+{
+	struct sb_name *name = sb_dev_to_name(sb_names, idx);
+	prt_printf(out, "Device %u:\t%s\t", idx, name ? name->name : "(not found)");
+
+	if (name) {
+		char *model = fd_to_dev_model(name->sb.bdev->bd_fd);
+		prt_str(out, model);
+		free(model);
+	}
+	prt_newline(out);
+
+	printbuf_indent_add(out, 2);
+	bch2_member_to_text(out, &m, gi, sb, idx);
+	printbuf_indent_sub(out, 2);
+}
+
+void bch2_sb_to_text_with_names(struct printbuf *out, struct bch_sb *sb,
+				bool print_layout, unsigned fields, int field_only)
+{
+	CLASS(printbuf, uuid_buf)();
+	prt_str(&uuid_buf, "UUID=");
+	pr_uuid(&uuid_buf, sb->user_uuid.b);
+
+	sb_names sb_names = {};
+	bch2_scan_device_sbs(uuid_buf.buf, &sb_names);
+
+	if (field_only >= 0) {
+		struct bch_sb_field *f = bch2_sb_field_get_id(sb, field_only);
+
+		if (f)
+			__bch2_sb_field_to_text(out, sb, f);
+	} else {
+		printbuf_tabstop_push(out, 44);
+
+		bch2_sb_to_text(out, sb, print_layout,
+				fields & ~(BIT(BCH_SB_FIELD_members_v1)|
+					   BIT(BCH_SB_FIELD_members_v2)));
+
+		struct bch_sb_field_disk_groups *gi = bch2_sb_field_get(sb, disk_groups);
+
+		struct bch_sb_field_members_v1 *mi1;
+		if ((fields & BIT(BCH_SB_FIELD_members_v1)) &&
+		    (mi1 = bch2_sb_field_get(sb, members_v1)))
+			for (unsigned i = 0; i < sb->nr_devices; i++)
+				print_one_member(out, sb_names, sb, gi, bch2_members_v1_get(mi1, i), i);
+
+		struct bch_sb_field_members_v2 *mi2;
+		if ((fields & BIT(BCH_SB_FIELD_members_v2)) &&
+		    (mi2 = bch2_sb_field_get(sb, members_v2)))
+			for (unsigned i = 0; i < sb->nr_devices; i++)
+				print_one_member(out, sb_names, sb, gi, bch2_members_v2_get(mi2, i), i);
+	}
+}
+
 int cmd_show_super(int argc, char *argv[])
 {
 	static const struct option longopts[] = {
@@ -98,32 +167,16 @@ int cmd_show_super(int argc, char *argv[])
 
 	if (print_default_fields) {
 		fields |= bch2_sb_field_get(sb.sb, members_v2)
-			? 1 << BCH_SB_FIELD_members_v2
-			: 1 << BCH_SB_FIELD_members_v1;
-		fields |= 1 << BCH_SB_FIELD_errors;
+			? BIT(BCH_SB_FIELD_members_v2)
+			: BIT(BCH_SB_FIELD_members_v1);
+		fields |= BIT(BCH_SB_FIELD_errors);
 	}
 
 	struct printbuf buf = PRINTBUF;
 
 	buf.human_readable_units = true;
 
-	if (field_only >= 0) {
-		struct bch_sb_field *f = bch2_sb_field_get_id(sb.sb, field_only);
-
-		if (f)
-			__bch2_sb_field_to_text(&buf, sb.sb, f);
-	} else {
-		printbuf_tabstop_push(&buf, 44);
-
-		char *model = fd_to_dev_model(sb.bdev->bd_fd);
-		prt_str(&buf, "Device:");
-		prt_tab(&buf);
-		prt_str(&buf, model);
-		prt_newline(&buf);
-		free(model);
-
-		bch2_sb_to_text(&buf, sb.sb, print_layout, fields);
-	}
+	bch2_sb_to_text_with_names(&buf, sb.sb, print_layout, fields, field_only);
 	printf("%s", buf.buf);
 
 	bch2_free_super(&sb);

c_src/cmd_super.h

@@ -0,0 +1,8 @@
+#ifndef _TOOLS_CMD_SHOW_SUPER_H
+#define _TOOLS_CMD_SHOW_SUPER_H
+
+#include "libbcachefs/super-io.h"
+
+void bch2_sb_to_text_with_names(struct printbuf *, struct bch_sb *, bool, unsigned, int);
+
+#endif /* _TOOLS_CMD_SHOW_SUPER_H */

src/device_scan.rs

@@ -1,5 +1,5 @@
 use std::{
-    ffi::{CStr, CString, c_char},
+    ffi::{CStr, CString, c_char, c_int},
     collections::HashMap,
     env,
     path::{Path, PathBuf},
@@ -7,7 +7,12 @@ use std::{
 };
 
 use anyhow::Result;
-use bch_bindgen::{bcachefs, bcachefs::bch_sb_handle, opt_set};
+use bch_bindgen::{bcachefs, opt_set};
+use bcachefs::{
+    bch_sb_handle,
+    sb_name,
+    sb_names,
+};
 use bcachefs::bch_opts;
 use uuid::Uuid;
 use log::debug;
@@ -185,13 +190,39 @@ pub fn scan_devices(device: &String, opts: &bch_opts) -> Result<String> {
     Ok(joined_device_str(&sbs))
 }
 
+#[no_mangle]
+pub extern "C" fn bch2_scan_device_sbs(device: *const c_char, ret: *mut sb_names) -> c_int {
+    let device = unsafe { CStr::from_ptr(device) };
+    let device = device.to_str().unwrap().to_string();
+
+    // how to initialize to default/empty?
+    let opts = bch_bindgen::opts::parse_mount_opts(None, None, true).unwrap_or_default();
+
+    let sbs = scan_sbs(&device, &opts).unwrap();
+
+    let mut sbs = sbs.iter()
+        .map(|(name, sb)| sb_name {
+            name: CString::new(name.clone().into_os_string().into_string().unwrap()).unwrap().into_raw(),
+            sb: *sb } )
+        .collect::<Vec<sb_name>>();
+
+    unsafe {
+        (*ret).data   = sbs.as_mut_ptr();
+        (*ret).nr     = sbs.len();
+        (*ret).size   = sbs.capacity();
+
+        std::mem::forget(sbs);
+    }
+    0
+}
+
 #[no_mangle]
 pub extern "C" fn bch2_scan_devices(device: *const c_char) -> *mut c_char {
     let device = unsafe { CStr::from_ptr(device) };
     let device = device.to_str().unwrap().to_string();
 
-    let opts = bch_bindgen::opts::parse_mount_opts(None, None, true)
-        .unwrap_or_default();
+    // how to initialize to default/empty?
+    let opts = bch_bindgen::opts::parse_mount_opts(None, None, true).unwrap_or_default();
 
     CString::new(scan_devices(&device, &opts).unwrap()).unwrap().into_raw()
 }

src/rust_to_c.h

@@ -1,6 +1,17 @@
 #ifndef _BCACHEFS_TOOLS_RUST_TO_C_H
 #define _BCACHEFS_TOOLS_RUST_TO_C_H
 
+#include "libbcachefs/super_types.h"
+#include "libbcachefs/darray.h"
+
+struct sb_name {
+	const char		*name;
+	struct bch_sb_handle	sb;
+};
+typedef DARRAY(struct sb_name) sb_names;
+
+int bch2_scan_device_sbs(char *, sb_names *ret);
+
 char *bch2_scan_devices(char *);
 
 #endif /* _BCACHEFS_TOOLS_RUST_TO_C_H */