Bug #51276: mds: avoid journaling overhead for setxattr("ceph.dir.subvolume") for no-op case - CephFS - Ceph

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Bug #51276

closed

mds: avoid journaling overhead for setxattr("ceph.dir.subvolume") for no-op case

Added by Patrick Donnelly almost 3 years ago. Updated over 1 year ago.

Status:

Resolved

Priority:

Urgent

Assignee:

Patrick Donnelly

Category:

Performance/Resource Usage

Target version:

Ceph - v17.0.0

% Done:

Source:

Development

Tags:

backport_processed

Backport:

pacific,octopus,nautilus

Regression:

Severity:

3 - minor

Reviewed:

Affected Versions:

ceph-qa-suite:

Component(FS):

MDS

Labels (FS):

Pull request ID:

41935

Crash signature (v1):

Crash signature (v2):

Description

In preparation for acquiring the xlock on the directory inode, the MDS must journal a few events before continuing on with the setvxattr. This can cause significant delays in the volumes ceph-mgr module which needs to regularly enable this vxattr from multiple code paths. We could cache in that module whether the vxattr is set but it's also pretty easy to adjust the MDS to acquire a rdlock on the directory to check if the subvolume flag is already set. That is much lighter weight and the lock is generally readily available.

Related issues 3 (0 open — 3 closed)