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This article mainly shows you "what is the use of LogSegment class in ceph", the content is simple and clear, and I hope it can help you solve your doubts. Let me lead you to study and learn this article "what is the use of LogSegment class in ceph".

The LogSegment class description:

Class LogSegment {

Const log_segment_seq_t seq; record LogSegment serial number

Uint64_t offset, end; record offset position and end position

Int num_events; records the number of event

Elist dirty_dirfrags, new_dirfrags; record the changing CDir structure.

Elist dirty_dentries; records changing CDentry structures.

Elist dirty_inodes; records changed CInode

Elist dirty_parent_inodes, dirty_dirfrag_dir, dirty_dirfrag_nest, dirty_dirfrag_dirfragtree

Elist open_files

...

}

LogSegment is used to record the information of the actual change of CDir/CDentry/CInode. LogSegment is the lowest data structure of the whole MDLog.

Methods of the LogSegment class:

LogSegment::try_to_expire (mds, gather_bld, op_prio)

| | _ _ traverse the new_dirfrags/dirty_dirfrags array |

| | _ _ insert the contents of the array into the commit array |

| | _ _ traverse the dirty_dentries array |

| | _ _ insert the CDentry::get_dir () of the member in the array into the commit array |

| | _ _ traverse the dirty_inodes array |

| | _ _ insert the CInode::get_parent_dn ():: get_dir () of the member in the array into the commit array |

| | _ _ traverse the commit array |

| | _ _ if commit array member can_auth_pin () |

| | _ _ CDir::commit () submit modifications to CDir |

| | _ _ if commit array member! can_auth_pin () |

| | _ CDir::add_waiter (CDir::WAIT_UNFREEZE) is added to the waiting queue |

| | _ _ traverse the uncommitted_masters array |

| | _ _ mds- > mdcache- > wait_for_uncommitted_master () waits for the client to reply commit |

| | _ _ traverse the uncommitted_fragments array |

| | _ _ mds- > mdcache- > wait_for_uncommitted_fragment () waits for fragment that does not receive commit |

| | _ _ traverse the dirty_dirfrag_dir array |

| | _ _ mds- > locker- > scatter_nudge () waits for dirlock flush |

| | _ _ traverse the dirty_dirfrag_dirfragtree array |

| | _ _ mds- > locker- > scatter_nudge () waits for dirfragtreelock flush |

| | _ _ traverse the dirty_dirfrag_nest array |

| | _ _ mds- > locker- > scatter_nudge () waits for nest flush |

| | _ _ traverse the open_files array |

| | CInode in _ _ array is authorized and has access permission |

| | _ _ if LogEvent is empty |

| | _ _ create a new EOpen class object |

| | _ _ mds- > mdlog- > start_entry (EOpen) writes a new EOpen class object to mdlog |

| | _ _ le- > add_clean_inode () add inode to the clean inode array of LogEvent |

| | _ _ ls- > open_files.push_back () is inserted into the open_files array of LogSegment |

| | CInode in _ _ array is authorized but does not have access permission |

| | _ _ in- > item_open_file.remove_myself () removes the CInode from the item_open_file array |

| | _ _ if le is not empty |

| | _ _ mds- > mdlog- > submit_entry (le) submit LogEvent to MDLog |

| | _ _ traverse the dirty_parent_inodes array |

| | _ _ if element can_auth_pin () in the array |

| | _ CInode::store_backtrace () |

| | _ _ if the elements in the array cannot can_auth_pin () |

| | _ _ CInode::add_waiter (CInode::WAIT_UNFREEZE) waiting for unfreeze |

| | _ _ traverse the slave_updates array |

| | _ _ update MDSlaveUpdate::waiter = gather_bld.new_sub () wait for slave update |

| | _ _ check whether inotablev is greater than mds- > inotable- > get_committed_version () |

| | _ _ mds- > inotable- > save () saves inotable |

| | _ _ check whether sessionmapv is greater than mds- > sessionmap.get_committed () |

| | _ _ mds- > sessionmap.save () saves sessionmap |

| | _ _ mds- > sessionmap.save_if_dirty () saves sessionmap |

| | _ _ traverse the pending_commit_tids array |

| | _ _ get MDSTableClient class objects from the array |

| | _ _ MDSTableClient::wait_for_ack () waits for the unanswered commit |

| | _ _ traverse the tablev array |

| | _ _ get MDSTableServer class objects from the array |

| | _ _ if the version value in tablev array is greater than MDSTableServer::get_committed_version () |

| | _ _ MDSTableServer::save () saves MDSTableServer |

| | _ _ traverse the truncating_inodes array |

| | _ _ CInode::add_waiter (CInode::WAIT_TRUNC) waiting for TRUNC |

| | _ _ mds- > mdlog- > flush () Refresh mdlog |

The above is all the content of the article "what is the use of LogSegment classes in ceph". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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