[LU-19967] take extent tree depth and sb into account for credits calculation

• Type: Bug
• Resolution: Fixed
• Priority: Medium
• Fix Version/s: Lustre 2.18.0
• Severity: 3
• Assignee: Alex Zhuravlev
• Reporter: Alex Zhuravlev

Description

current logic is not correct

                depth = inode != NULL ? ext_depth(inode) : 0;
                depth = min(max(depth, 1) + 3, LDISKFS_MAX_EXTENT_DEPTH);
                credits = depth; 

depth can't grow by 3 in a single transaction.
rather it should be like:

                depth = inode != NULL ? ext_depth(inode) : 0;
                depth = min(max(depth, 1) + 1, LDISKFS_MAX_EXTENT_DEPTH);
                credits = (depth-1) * 2; 

Issue Links

• is related to: LU-18763 LBUG on multiple MDS while adding OSTs - journal_dirty_metadata failed: handle type 0 started at line 1994, credits 5/0, errcode -28