src/doc: fix class names in exports.txt

src/doc/exports.txt → doc/dev/mds_internals/exports.rst

@@ -1,5 +1,10 @@
 
-NORMAL MIGRATION
+===============
+Subtree exports
+===============
+
+Normal Migration
+----------------
 
 The exporter begins by doing some checks in export_dir() to verify
 that it is permissible to export the subtree at this time.  In
@@ -10,28 +15,28 @@ conflicted with a rename).  If these conditions are met, the subtree
 freeze is initiated, and the exporter is committed to the subtree
 migration, barring an intervening failure of the importer or itself.
 
-The MExportDiscover serves simply to ensure that the base directory
+The MExportDirDiscover serves simply to ensure that the base directory
 being exported is open on the destination node.  It is pinned by the
 importer to prevent it from being trimmed.  This occurs before the
 exporter completes the freeze of the subtree to ensure that the
 importer is able to replicate the necessary metadata.  When the
-exporter receives the MDiscoverAck, it allows the freeze to proceed.
+exporter receives the MExportDirDiscoverAck, it allows the freeze to proceed.
 
-The MExportPrep message then follows to populate a spanning tree that
+The MExportDirPrep message then follows to populate a spanning tree that
 includes all dirs, inodes, and dentries necessary to reach any nested
 exports within the exported region.  This replicates metadata as well,
 but it is pushed out by the exporter, avoiding deadlock with the
 regular discover and replication process.  The importer is responsible
 for opening the bounding directories from any third parties before
 acknowledging.  This ensures that the importer has correct dir_auth
 information about where authority is delegated for all points nested
-within the subtree being migrated.  While processing the MExportPrep,
+within the subtree being migrated.  While processing the MExportDirPrep,
 the importer freezes the entire subtree region to prevent any new
 replication or cache expiration.
 
 The warning stage occurs only if the base subtree directory is open by
 nodes other than the importer and exporter.  If so, then a
-MExportWarning message informs any bystanders that the authority for
+MExportDirNotify message informs any bystanders that the authority for
 the region is temporarily ambiguous.  In particular, bystanders who
 are trimming items from their cache must send MCacheExpire messages to
 both the old and new authorities.  This is necessary to ensure that
@@ -41,21 +46,20 @@ importer and exporter), expirations will not be immediately processed;
 instead, they will be queued until the region is unfrozen and it can
 be determined that the node is or is not authoritative for the region.
 
-The MExport message sends the actual subtree metadata to the importer.
+The MExportDir message sends the actual subtree metadata to the importer.
 Upon receipt, the importer inserts the data into its cache, logs a
-copy in the EImportStart, and replies with an ExportAck.  The exporter
-can now log an EExportFinish(true), which ultimately specifies that
+copy in the EImportStart, and replies with an MExportDirAck.  The exporter
+can now log an EExport, which ultimately specifies that
 the export was a success.  In the presence of failures, it is the
-existence (and value) of the EExportFinish that disambiguates
-authority during recovery.
+existence  of the EExport that disambiguates authority during recovery.
 
-Once logged, the exporter will send an MExportNotify to any
+Once logged, the exporter will send an MExportDirNotify to any
 bystanders, informing them that the authority is no longer ambiguous
 and cache expirations should be sent only to the new authority (the
 importer).  Once these are acknowledged, implicitly flushing the
 bystander to exporter message streams of any stray expiration notices,
 the exporter unfreezes the subtree, cleans up its state, and sends a
-final MExportFinish to the importer.  Upon receipt, the importer logs
+final MExportDirFinish to the importer.  Upon receipt, the importer logs
 an EImportFinish(true), unfreezes its subtree, and cleans up its
 state.