[LU-14719] "lfs migrate -m" creates broken agent inodes when target MDT full

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.16.0
• Affects Version/s: Lustre 2.12.3
• Labels: migration_improvements
• Severity: 3
• Assignee: Lai Siyao
• Reporter: Andreas Dilger

Description

mds02 kernel: LustreError: 8471:0:(osd_handler.c:3892:osd_create_local_agent_inode()) lfs1-MDT0001: [0x200026991:0x560d:0x0] add dot dotdot error: rc = -28
mds02 kernel: LustreError: 8471:0:(out_lib.c:1190:out_tx_index_delete_undo()) lfs1-MDT0001-osd: Oops, can not rollback index_delete yet: rc = -524
mds02 kernel: LustreError: 8471:0:(out_handler.c:915:out_tx_end()) lfs1-MDT0001-osd: undo for lustre/target/out_handler.c:454: rc = -524
mds02 kernel: LustreError: 22380:0:(osd_handler.c:3892:osd_create_local_agent_inode()) lfs1-MDT0001: [0x200026991:0x5613:0x0] add dot dotdot error: rc = -28
mds02 kernel: LustreError: 22380:0:(osd_handler.c:3892:osd_create_local_agent_inode()) Skipped 2 previous similar messages
mds02 kernel: LustreError: 22380:0:(out_lib.c:1190:out_tx_index_delete_undo()) lfs1-MDT0001-osd: Oops, can not rollback index_delete yet: rc = -524
mds02 kernel: LustreError: 22380:0:(out_lib.c:1190:out_tx_index_delete_undo()) Skipped 5 previous similar messages
mds02 kernel: LustreError: 22380:0:(out_handler.c:915:out_tx_end()) lfs1-MDT0001-osd: undo for lustre/target/out_handler.c:454: rc = -524

When e2fsck is run on the filesystem (LU-14710) it reports that the "." and ".." entries are corrupted, and can also report that the HTree index is corrupted:

Directory entry for '.' in ... (1032783) is big.
Split? no
Second entry '3.3.0' (inode=538027 fid=[0x380020941:0x4c38:0x0]) in directory inode 1032783 should be '..'
Fix? no

This should be handled better by the MDS:

• check that the target MDT has enough space before starting migration
• if ENOSPC is returned before directory is migrated then clean up unused agent inodes

Issue Links

• is related to: LU-16467 lod_trans_space_check() fails with -28 during file unlink
• is related to: LU-13832 "lfs migrate -m" leads to inconsistent ldiskfs directories
• is related to: LU-14211 DNE3: mechanism to interrupt and resume migration
• is related to: LU-11776 add "lfs find" support for directory hash flags
• is related to: LU-15990 "lfs find" to scan for directory hash flags
• is related to: LU-14710 check_dot() does not handle dirdata/FID entry properly
• is related to: LU-15868 LFSCK fix inconsistencies in directory migration failure
• is related to: LU-15001 improve recovery of interrupted directory migrate