[LU-10131] Update inode attributes on unlink

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.11.0, Lustre 2.10.2
• Severity: 3
• Assignee: Patrick Farrell
• Reporter: Patrick Farrell

Description

Currently, the last unlink of an inode sends back the inode attributes from the MDS, but the client ignores them. This results in i_nlink on the inode (in memory on the client) staying at one after it has been fully unlinked, which means it stays in memory until discarded from pressure. This is also problematic for wrapfs atop Lustre, would like to use the nlink count to be certain the file is really gone.

The only attribute which is relevant on a fully unlinked inode is i_nlink, so we just read that out. Patch coming momentarily.

Issue Links

• is related to: LU-2857 2.1.4<->2.4.0 interop: sanity test_76: FAIL: inode slab grew from 11183 to 12183
• is related to: LU-7925 ll_d_iput() can clear i_nlink for an inode in use
• is related to: LU-2036 sanity.sh test_76: fails with lod/osp (inodes are not purged as expected)