[LU-15609] Client should not assume RDONLY implies SOM

• Type: Bug
• Resolution: Fixed
• Priority: Critical
• Fix Version/s: Lustre 2.16.0
• Severity: 3
• Assignee: Patrick Farrell (Inactive)
• Reporter: Patrick Farrell (Inactive)

Description

In lov_io_slice_mirror_init, the client code assumes that a RDONLY flag in the layout implies SOM and skips glimpse if so.  This is something like a layering violation - SOM is communicated from the MDS when it is valid, and the client already skips glimpse in that case.

Prior to "LU-14526 flr: mirror split downgrade SOM"/https://review.whamcloud.com/43168/, this was incorrect but not a problem, because LCM_FL_RDONLY always implied valid SOM.    That patch made that assumption invalid.

Fix is for client not to assume LCM_FL_RDONLY means SOM.

Issue Links

• is related to: LU-11695 disabling the xattr cache on client for LSOM