David,

  And this one could also merge?

Thanks, Anand


On 21/10/21 11:31 pm, Anand Jain wrote:

v2:
Fix sysfs_emit conversion at the two non-sysfs show functions in patch1.

btrfs-progs tries to read the fsid from the super-block for a missing
device and, it fails. It needs to find out if the device is a seed
device. It does it by comparing the device's fsid with the fsid of the
mounted filesystem. To help this scenario introduce a new sysfs file to
read the fsid from the kernel.
      /sys/fs/btrfs/<fsid>/devinfo/<devid>/fsid

Patch 1 is a cleanup converts scnprtin()f and snprintf() to sysfs_emit()
Patch 2 introduces the new sysfs interface as above

The other implementation choice is to add another parameter to the
struct btrfs_ioctl_dev_info_args and use BTRFS_IOC_DEV_INFO ioctl. But
then backward kernel compatibility with the newer btrfs-progs is more
complicated. If needed, we can add that too.

Related btrfs-progs patches:
   btrfs-progs: prepare helper device_is_seed
   btrfs-progs: read fsid from the sysfs in device_is_seed

Anand Jain (2):
   btrfs: sysfs convert scnprintf and snprintf to use sysfs_emit
   btrfs: sysfs add devinfo/fsid to retrieve fsid from the device

  fs/btrfs/sysfs.c | 106 +++++++++++++++++++++++++----------------------
  1 file changed, 57 insertions(+), 49 deletions(-)