btrfs-progs: change load_device_info to chunk tree search solution

Commit Message

hmsjwzb Dec. 11, 2022, 11:20 p.m. UTC

From: "Flint.Wang" <[e-mail]>

btrfs/249 fails due to unexpected number of devices

[How to reproduce]
mkfs.btrfs -f -d raid1 -m raid1 /dev/sdb /dev/sdc
btrfstune -S 1 /dev/sdb
wipefs -a /dev/sdb
mount -o degrade /dev/sdc /mnt/scratch
btrfs device add -f /dev/sdd /mnt/scratch
btrfs filesystem usage /mnt/scratch

[Root cause]
ioctl call BTRFS_IOC_FS_INFO returns both rw device and seed device.
It will cause device number mismatch issues.

[How to Fix]
This patch introduce function load_devid which only return the information
of rw devices.

Signed-off-by: Flint.Wang <[e-mail]>
---
 cmds/filesystem-usage.c | 81 +++++++++++++++++++++++++++++++++++------
 1 file changed, 70 insertions(+), 11 deletions(-)

Patch

diff --git a/cmds/filesystem-usage.c b/cmds/filesystem-usage.c
index 5810324f..887fe034 100644
--- a/cmds/filesystem-usage.c
+++ b/cmds/filesystem-usage.c
@@ -27,6 +27,7 @@ 
 #include <fcntl.h>
 #include <dirent.h>
 #include <limits.h>
+#include <uuid/uuid.h>
 #include "kernel-lib/sizes.h"
 #include "kernel-shared/ctree.h"
 #include "kernel-shared/disk-io.h"
@@ -700,6 +701,65 @@  out:
 	return ret;
 }
 
+/*
+ * This function searches chunk tree to find rw_devs
+ */
+static int load_devid(int fd, struct device_info *info,
+		int ndev, u8 *fsid)
+{
+	struct btrfs_ioctl_search_args_v2 *args2;
+	struct btrfs_ioctl_search_key *sk;
+	struct btrfs_ioctl_search_header *sh;
+	struct btrfs_dev_item *dev_item;
+	int args2_size = 1024;
+	char args2_buf[args2_size];
+	int ret = 0;
+	int i = 0;
+	int num = 0;
+	int rw_devs = 0;
+	int idx = 0;
+
+	args2 = (struct btrfs_ioctl_search_args_v2 *) args2_buf;
+	sk = &(args2->key);
+
+	sk->tree_id = BTRFS_CHUNK_TREE_OBJECTID;
+	sk->min_objectid = BTRFS_DEV_ITEMS_OBJECTID;
+	sk->max_objectid = BTRFS_DEV_ITEMS_OBJECTID;
+	sk->min_type = BTRFS_DEV_ITEM_KEY;
+	sk->max_type = BTRFS_DEV_ITEM_KEY;
+	sk->min_offset = 0;
+	sk->max_offset = (u64)-1;
+	sk->min_transid = 0;
+	sk->max_transid = (u64)-1;
+	sk->nr_items = -1;
+	args2->buf_size = args2_size - sizeof(struct btrfs_ioctl_search_args_v2);
+	ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH_V2, args2);
+	if (ret != 0)
+		return -1;
+
+	sh = (struct btrfs_ioctl_search_header *) args2->buf;
+	num = sk->nr_items;
+
+	dev_item = (struct btrfs_dev_item *) (sh + 1);
+	for (i = 0; i < num; i++) {
+		if (!uuid_compare(dev_item->fsid, fsid)) {
+			rw_devs += 1;
+			info[idx++].devid = dev_item->devid;
+		}
+		if (idx > ndev) {
+			error("unexpected number of devices: %d >= %d", idx, ndev);
+			return -1;
+		}
+		sh = (struct btrfs_ioctl_search_header *) dev_item + 1;
+		dev_item = (struct btrfs_dev_item *) sh + 1;
+	}
+
+	if (ndev != rw_devs)
+		error("unexpected number of devices: %d != %d", ndev, rw_devs);
+
+	return 0;
+}
+
 /*
  *  This function loads the device_info structure and put them in an array
  */
@@ -729,19 +789,18 @@  static int load_device_info(int fd, struct device_info **devinfo_ret,
 		return 1;
 	}
 
-	for (i = 0, ndevs = 0 ; i <= fi_args.max_id ; i++) {
-		if (ndevs >= fi_args.num_devices) {
-			error("unexpected number of devices: %d >= %llu", ndevs,
-				fi_args.num_devices);
-			error(
-		"if seed device is used, try running this command as root");
-			goto out;
-		}
+	ret = load_devid(fd, info, fi_args.num_devices, fi_args.fsid);
+	if (ret == -1)
+		goto out;
+
+	for (i = 0, ndevs = 0; i < fi_args.num_devices; i++) {
 		memset(&dev_info, 0, sizeof(dev_info));
-		ret = get_device_info(fd, i, &dev_info);
+		ret = get_device_info(fd, info[i].devid, &dev_info);
+
+		if (ret == -ENODEV) {
+			error("device not found\n");
+		}
 
-		if (ret == -ENODEV)
-			continue;
 		if (ret) {
 			error("cannot get info about device devid=%d", i);
 			goto out;