[LU-13121] ll_update_lsm_md() may deadlock

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.14.0, Lustre 2.12.4
• Affects Version/s: Lustre 2.12.0, Lustre 2.13.0
• Severity: 3
• Assignee: Lai Siyao
• Reporter: Lai Siyao

Description

ll_update_lsm_md() down_write() if lli->lli_lsm_md is NULL, and tries to initialize it, but if a concurrent lookup initialized lli->lli_lsm_md after this check and before taking write lock, it will up_read(), so the write lock is not released, therefore subsequent lookup will deadlock on this.

Issue Links

• is related to: LU-13099 ll_set_inode()) Can not initialize inode warning