During disk replacement a new disk is temporarily added to the fs devlist with devid 0 and fs num_device is incremented by 1. However when progs reads the devlist it fail to obtain details of devid 0 because it doesn't query devid 0 at all.
reproducer: btrfs rep start /dev/sdb /dev/sdf /btrfs btrfs fi show Label: none uuid: f8fb9819-16c8-47b7-b62f-0ff90f8c56cd Total devices 3 FS bytes used 1.94GiB devid 1 size 1.10GiB used 1.10GiB path /dev/sdb devid 2 size 1.10GiB used 1.08GiB path /dev/sdc devid 0 size 0.00 used 0.00 path this patch will make it proper by querying devid 0. btrfs repl start /dev/sdb /dev/sdf /btrfs btrfs fi show /btrfs Label: none uuid: f8fb9819-16c8-47b7-b62f-0ff90f8c56cd Total devices 3 FS bytes used 1.94GiB devid 0 size 1.10GiB used 1.10GiB path /dev/sdf devid 1 size 1.10GiB used 1.10GiB path /dev/sdb devid 2 size 1.10GiB used 1.08GiB path /dev/sdc Its fine to query devid 0 when there is no replace activity as well, because we just skip the error ENODEV btrfs fi show /btrfs Label: none uuid: f8fb9819-16c8-47b7-b62f-0ff90f8c56cd Total devices 2 FS bytes used 1.94GiB devid 1 size 1.10GiB used 1.10GiB path /dev/sdf devid 2 size 1.10GiB used 1.08GiB path /dev/sdc --- v2: fix commit message utils.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/utils.c b/utils.c index de513b6..a045ffd 100644 --- a/utils.c +++ b/utils.c @@ -1696,7 +1696,7 @@ int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args, goto out; } - for (; i <= fi_args->max_id; ++i) { + for (i = 0; i <= fi_args->max_id; ++i) { BUG_ON(ndevs >= fi_args->num_devices); ret = get_device_info(fd, i, &di_args[ndevs]); if (ret == -ENODEV) -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html