CVE-2026-98897: ksmbd: don't hold ci->m_lock while waiting for a lease break ack

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: don't hold ci->mlock while waiting for a lease break ack

When a cifs.ko client caches a read-handle (RH) lease via deferred close and a conflicting open arrives, ksmbd breaks the lease and waits for the acknowledgment in waitforbreakack() for up to OPLOCKWAITTIME (35s). smbbreakalllevIIoplock() runs that wait while holding ci->mlock for read.

cifs.ko reacts to a handle-lease break by closing the deferred handle rather than sending a lease break acknowledgment. That close path (closeiddeloplock() -> opinfodel()) takes ci->mlock for write and is exactly what would wake the waiter, but it blocks on the read lock held by the waiting thread. The break is then resolved only by the 35s timeout, so xfstests generic/001 takes ~78s with leases enabled versus ~4s with oplocks only.

Collect the target opinfos (each pinned with a reference) while holding ci->mlock, then break them after releasing it, matching how smbgrantoplock() already breaks a conflicting lease using only a reference. The reference keeps the opinfo (and its conn and lease) alive across the unlocked window, and a close racing the break is handled by the existing OPLOCKCLOSING state check. Apply the same fix to the parent lease break paths.