btrfs-progs: do a separate probe for transient replacing device

As mentioned in the kernel patch

btrfs: ioctl BTRFS_IOC_FS_INFO and
 BTRFS_IOC_DEV_INFO miss-matched with slots

The count as returned by BTRFS_IOC_FS_INFO is the number of slots that
btrfs-progs would allocate for the BTRFS_IOC_DEV_INFO ioctl. Since
BTRFS_IOC_DEV_INFO would loop across the seed devices, So its better
ioctl BTRFS_IOC_FS_INFO returns the total_devices instead of num_devices.

The above mentioned patch just does that. That is, it returns
total_devices instead of num_devices.

Which means we need to probe for the replacing device separately.

This patch will probe for the replacing device separately.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>

1 files changed, 18 insertions, 1 deletions

diff --git a/utils.c b/utils.c
index e9306b05..40b8f1a3 100644
--- a/utils.c
+++ b/utils.c
@@ -1819,12 +1819,29 @@ int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args,
 	if (!fi_args->num_devices)
 		goto out;
 
-	di_args = *di_ret = malloc(fi_args->num_devices * sizeof(*di_args));
+	/*
+	 * with kernel patch
+	 * btrfs: ioctl BTRFS_IOC_FS_INFO and BTRFS_IOC_DEV_INFO miss-matched with slots
+	 * the kernel now returns total_devices which does not include
+	 * replacing device if running.
+	 * As we need to get dev info of the replace device if it is running,
+	 * so just add one to fi_args->num_devices.
+	 */
+
+	di_args = *di_ret = malloc((fi_args->num_devices + 1) * sizeof(*di_args));
 	if (!di_args) {
 		ret = -errno;
 		goto out;
 	}
 
+	/* get the replace target device if it is there */
+	ret = get_device_info(fd, i, &di_args[ndevs]);
+	if (!ret) {
+		ndevs++;
+		fi_args->num_devices++;
+	}
+	i++;
+
 	for (; i <= fi_args->max_id; ++i) {
 		BUG_ON(ndevs >= fi_args->num_devices);
 		ret = get_device_info(fd, i, &di_args[ndevs]);