[LU-11882] OST recreated objects gets badness mark from e2fsck

Gantt End to Start — Thu, 30 May 2019 12:09:45 +0000

e2fsck spends 72 hours to check ~113T OST. Most time in phase 2.

Profiler shows that most expensive path is:

e2fsck_run -> e2fsck_pass2 ->  check_dir_block -> e2fsck_process_bad_inode -> e2fsck_read_inode

After adding -d option we get millions of such messages:

e2fsck_pass1:1543: increase inode 12485987 badness 0 to 2

Which correspond to this piece of code:

else if (EXT4_XTIME_ANCIENT(ctx, sb, inode->i_ctime,
                                            ctx->time_fudge))
                        e2fsck_mark_inode_bad(ctx, ino, BADNESS_HIGH);

Code check if ctime is too old. But Lustre FS adds precreated object with zeroed time. So every such object assumed as bad by e2fsck. By some reasons (this is other issue topic) we get millions of precreated files and e2fsck spends a lot of time to process this file during phase 2.

After removing check above e2fsck completes its work after 20 minutes.

Two possible solutions are suggested: 1) remove this check, because having zeroed chime is possible situation for Lustre FS 2) remove inode badness patches. Does it give enough advantages for such overhead.

Whamcloud Community JIRA

[LU-11882] OST recreated objects gets badness mark from e2fsck