Original ubifs code was designed that after ubifs_umount() call it is
required to also call ubi_close_volume() which closes underlying UBI
volume. But U-Boot ubifs modification have not implemented it properly
which caused that ubifsumount command contains resource leak. It can be
observed by calling simple sequence of commands:
=> ubi part mtd2
ubi0: attaching mtd2
...
=> ubifsmount ubi0
=> ubifsumount
Unmounting UBIFS volume rootfs!
=> ubi detach
ubi0 error: ubi_detach_mtd_dev: ubi0 reference count 1, destroy anyway
ubi0: detaching mtd2
ubi0: mtd2 is detached
Fix this issue by calling ubi_close_volume() and mutex_unlock() in
directly in ubifs_umount() function before freeing U-Boot's global
ubifs_sb. And remove duplicate calls of these two functions in remaining
places. Note that when ubifs_umount() is not called then during error
handling is still needed to call ubi_close_volume() and mutex_unlock.
With this change ubifsumount command does not throw that error anymore:
=> ubi part rootfs
ubi0: attaching mtd2
...
=> ubifsmount ubi0
=> ubifsumount
Unmounting UBIFS volume rootfs!
=> ubi detach
ubi0: detaching mtd2
ubi0: mtd2 is detached
Signed-off-by: Pali Rohár <pali@kernel.org>
69ca709d0f