In the MS client methods for manipulating the metadata tree, serve back

the write nonce of the affected entry to the caller.  For UGs, this
eliminates the need for revalidating a locally-created or
locally-updated file after the update but in the absence of other
updates (since the UG will already have
the most recent information anyway, there is no need to update unless
the write nonce changes after the update was issued).

UG/consistency.cpp

@@ -1521,7 +1521,7 @@ int fs_entry_coordinate( struct fs_core* core, char const* fs_path, struct fs_en
 
    // try to become the coordinator
    uint64_t current_coordinator = 0;
-   rc = ms_client_coordinate( core->ms, &current_coordinator, &ent );
+   rc = ms_client_coordinate( core->ms, &current_coordinator, &fent->write_nonce, &ent );
 
    if( rc != 0 ) {
       // failed to contact the MS

UG/fs/mkdir.cpp

@@ -129,8 +129,8 @@ int fs_entry_mkdir( struct fs_core* core, char const* path, mode_t mode, uint64_
       fs_entry_to_md_entry( core, &data, child, parent_id, parent_name );
       free( parent_name );
 
-      // make the directory on the MS, filling in the file ID into the child
-      err = ms_client_mkdir( core->ms, &child->file_id, &data );
+      // make the directory on the MS, filling in the file ID and write nonce into the child
+      err = ms_client_mkdir( core->ms, &child->file_id, &child->write_nonce, &data );
 
       if( err != 0 ) {
          errorf("ms_client_create(%s) rc = %d\n", path, err );

UG/fs/open.cpp

@@ -157,8 +157,8 @@ int fs_entry_mknod( struct fs_core* core, char const* path, mode_t mode, dev_t d
          struct md_entry data;
          fs_entry_to_md_entry( core, &data, child, parent_id, parent_name );
 
-         // create the child on the MS, obtaining its file ID
-         err = ms_client_create( core->ms, &child->file_id, &data );
+         // create the child on the MS, obtaining its file ID and write nonce
+         err = ms_client_create( core->ms, &child->file_id, &child->write_nonce, &data );
 
          md_entry_free( &data );
 
@@ -487,8 +487,8 @@ struct fs_file_handle* fs_entry_open( struct fs_core* core, char const* _path, u
       struct md_entry data;
       fs_entry_to_md_entry( core, &data, child, parent_id, parent_name );
 
-      // create synchronously, obtaining the child's file ID
-      *err = ms_client_create( core->ms, &child->file_id, &data );
+      // create synchronously, obtaining the child's file ID and write_nonce
+      *err = ms_client_create( core->ms, &child->file_id, &child->write_nonce, &data );
 
       if( *err != 0 ) {
          errorf("ms_client_create(%s) rc = %d\n", _path, *err );

UG/fs/rename.cpp

@@ -335,7 +335,7 @@ int fs_entry_versioned_rename( struct fs_core* core, char const* old_path, char
          }
          if( err == 0 ) {
             // rename on the MS 
-            err = ms_client_rename( core->ms, &old_ent, &new_ent );
+            err = ms_client_rename( core->ms, &fent_old->write_nonce, &old_ent, &new_ent );
             if( err != 0 ) {
                errorf("ms_client_rename(%s --> %s) rc = %d\n", old_ent.name, new_ent.name, err );
             }
@@ -351,7 +351,7 @@ int fs_entry_versioned_rename( struct fs_core* core, char const* old_path, char
       }
       else {
          // do the rename on the MS
-         err = ms_client_rename( core->ms, &old_ent, &new_ent );
+         err = ms_client_rename( core->ms, &fent_old->write_nonce, &old_ent, &new_ent );
          if( err != 0 ) {
             errorf("ms_client_rename(%s --> %s) rc = %d\n", old_ent.name, new_ent.name, err );
          }

UG/fs/stat.cpp

@@ -516,7 +516,7 @@ int fs_entry_chown( struct fs_core* core, char const* path, uint64_t user, uint6
    struct md_entry up;
    fs_entry_to_md_entry( core, &up, fent, parent_id, parent_name );
 
-   int rc = ms_client_update( core->ms, &up );
+   int rc = ms_client_update( core->ms, &fent->write_nonce, &up );
    if( rc != 0 ) {
       errorf("ms_client_update(%s) rc = %d\n", path, rc );
    }
@@ -556,7 +556,7 @@ int fs_entry_chmod( struct fs_core* core, char const* path, uint64_t user, uint6
    struct md_entry up;
    fs_entry_to_md_entry( core, &up, fent, parent_id, parent_name );
 
-   int rc = ms_client_update( core->ms, &up );
+   int rc = ms_client_update( core->ms, &fent->write_nonce, &up );
    if( rc != 0 ) {
       errorf("ms_client_update(%s) rc = %d\n", path, rc );
    }
@@ -611,7 +611,7 @@ int fs_entry_utime( struct fs_core* core, char const* path, struct utimbuf* tb,
    struct md_entry up;
    fs_entry_to_md_entry( core, &up, fent, parent_id, parent_name );
 
-   int rc = ms_client_update( core->ms, &up );
+   int rc = ms_client_update( core->ms, &fent->write_nonce, &up );
    if( rc != 0 ) {
       errorf("ms_client_update(%s) rc = %d\n", path, rc );
    }

UG/fs/sync.cpp

@@ -557,7 +557,7 @@ int fs_entry_fsync_metadata( struct fs_core* core, struct fs_file_handle* fh, st
 
       fs_entry_list_block_ids( sync_ctx->dirty_blocks, &affected_blocks, &num_affected_blocks );
 
-      rc = ms_client_update_write( core->ms, &sync_ctx->md_snapshot, affected_blocks, num_affected_blocks );
+      rc = ms_client_update_write( core->ms, &fh->fent->write_nonce, &sync_ctx->md_snapshot, affected_blocks, num_affected_blocks );
 
       // free memory 
       if( affected_blocks != NULL ) {

UG/fs/trunc.cpp

@@ -188,7 +188,7 @@ static int fs_entry_reversion_file( struct fs_core* core, char const* fs_path, s
    fs_entry_to_md_entry( core, &ent, fent, parent_id, parent_name );
 
    // synchronously update
-   rc = ms_client_update( core->ms, &ent );
+   rc = ms_client_update( core->ms, &fent->write_nonce, &ent );
 
    md_entry_free( &ent );
 

UG/fs/write.cpp

@@ -1196,7 +1196,7 @@ int fs_entry_remote_write( struct fs_core* core, char const* fs_path, uint64_t f
 
       fs_entry_list_write_message_blocks( write_msg, &affected_blocks, &num_affected_blocks );
 
-      err = ms_client_update_write( core->ms, &data, affected_blocks, num_affected_blocks );
+      err = ms_client_update_write( core->ms, &fent->write_nonce, &data, affected_blocks, num_affected_blocks );
 
       if( err != 0 ) {
          errorf("%ms_client_update(%s) rc = %d\n", fs_path, err );

libsyndicate/ms-client.cpp

@@ -2808,7 +2808,7 @@ uint64_t ms_client_make_file_id() {
 
 
 // create a file record on the MS, synchronously
-int ms_client_create( struct ms_client* client, uint64_t* file_id_ret, struct md_entry* ent ) {
+int ms_client_create( struct ms_client* client, uint64_t* file_id_ret, int64_t* write_nonce_ret, struct md_entry* ent ) {
    ent->type = MD_ENTRY_FILE;
 
    uint64_t file_id = ms_client_make_file_id();
@@ -2827,10 +2827,13 @@ int ms_client_create( struct ms_client* client, uint64_t* file_id_ret, struct md
    int rc = ms_client_file_post( client, &up, &reply );
 
    if( rc == 0 ) {
-      // did we get back a file_id?
+      // did we get back a file_id and write_nonce?
       if( reply.listing().entries_size() > 0 ) {
+
          *file_id_ret = reply.listing().entries(0).file_id();
-         dbprintf("output file_id: %" PRIX64 "\n", *file_id_ret );
+         *write_nonce_ret = reply.listing().entries(0).write_nonce();
+
+         dbprintf("output file_id: %" PRIX64 " write_nonce: %" PRId64 "\n", *file_id_ret, *write_nonce_ret );
       }
       else {
          rc = -ENODATA;
@@ -2844,7 +2847,7 @@ int ms_client_create( struct ms_client* client, uint64_t* file_id_ret, struct md
 
 
 // make a directory on the MS, synchronously
-int ms_client_mkdir( struct ms_client* client, uint64_t* file_id_ret, struct md_entry* ent ) {   
+int ms_client_mkdir( struct ms_client* client, uint64_t* file_id_ret, int64_t* write_nonce_ret, struct md_entry* ent ) {   
    ent->type = MD_ENTRY_DIR;
 
    uint64_t file_id = ms_client_make_file_id();
@@ -2867,10 +2870,13 @@ int ms_client_mkdir( struct ms_client* client, uint64_t* file_id_ret, struct md_
    int rc = ms_client_file_post( client, &up, &reply );
 
    if( rc == 0 ) {
-      // did we get back a file_id?
+      // did we get back a file_id and write_nonce?
       if( reply.listing().entries_size() > 0 ) {
+
          *file_id_ret = reply.listing().entries(0).file_id();
-         dbprintf("output file_id: %" PRIX64 "\n", *file_id_ret );
+         *write_nonce_ret = reply.listing().entries(0).write_nonce();
+
+         dbprintf("output file_id: %" PRIX64 " write_nonce: %" PRId64 "\n", *file_id_ret, *write_nonce_ret );
       }
       else {
          rc = -ENODATA;
@@ -2893,7 +2899,7 @@ int ms_client_delete( struct ms_client* client, struct md_entry* ent ) {
 }
 
 // update a record on the MS, synchronously, due to a write()
-int ms_client_update_write( struct ms_client* client, struct md_entry* ent, uint64_t* in_affected_blocks, size_t num_affected_blocks ) {
+int ms_client_update_write( struct ms_client* client, int64_t* write_nonce_ret, struct md_entry* ent, uint64_t* in_affected_blocks, size_t num_affected_blocks ) {
 
    // generate our update
    struct md_update up;
@@ -2912,7 +2918,22 @@ int ms_client_update_write( struct ms_client* client, struct md_entry* ent, uint
 
    up.num_affected_blocks = num_affected_blocks;
 
-   int rc = ms_client_file_post( client, &up, NULL );
+   ms::ms_reply reply;
+
+   int rc = ms_client_file_post( client, &up, &reply );
+
+   if( rc == 0 ) {
+      // did we get back a write_nonce?
+      if( reply.listing().entries_size() > 0 ) {
+
+         *write_nonce_ret = reply.listing().entries(0).write_nonce();
+
+         dbprintf("updated write_nonce: %" PRId64 "\n", *write_nonce_ret );
+      }
+      else {
+         rc = -ENODATA;
+      }
+   }
 
    // clean up
    if( affected_blocks != NULL ) {
@@ -2925,12 +2946,12 @@ int ms_client_update_write( struct ms_client* client, struct md_entry* ent, uint
 }
 
 // update a record on the MS, synchronously, NOT due to a write()
-int ms_client_update( struct ms_client* client, struct md_entry* ent ) {
-   return ms_client_update_write( client, ent, NULL, 0 );
+int ms_client_update( struct ms_client* client, int64_t* write_nonce_ret, struct md_entry* ent ) {
+   return ms_client_update_write( client, write_nonce_ret, ent, NULL, 0 );
 }
 
 // change coordinator ownership of a file on the MS, synchronously
-int ms_client_coordinate( struct ms_client* client, uint64_t* new_coordinator, struct md_entry* ent ) {
+int ms_client_coordinate( struct ms_client* client, uint64_t* new_coordinator, int64_t* write_nonce, struct md_entry* ent ) {
 
    // generate our update
    struct md_update up;
@@ -2944,8 +2965,11 @@ int ms_client_coordinate( struct ms_client* client, uint64_t* new_coordinator, s
    if( rc == 0 ) {
       // got back a coordinator?
       if( reply.listing().entries_size() > 0 ) {
+
          *new_coordinator = reply.listing().entries(0).coordinator();
-         dbprintf("New coordinator of %" PRIX64 " is %" PRIu64 "\n", ent->file_id, *new_coordinator );
+         *write_nonce = reply.listing().entries(0).write_nonce();
+
+         dbprintf("New coordinator of %" PRIX64 " is %" PRIu64 ", write_nonce = %" PRId64 "\n", ent->file_id, *new_coordinator, *write_nonce );
       }
       else {
          rc = -ENODATA;
@@ -2956,7 +2980,7 @@ int ms_client_coordinate( struct ms_client* client, uint64_t* new_coordinator, s
 }
 
 // rename from src to dest 
-int ms_client_rename( struct ms_client* client, struct md_entry* src, struct md_entry* dest ) {
+int ms_client_rename( struct ms_client* client, int64_t* write_nonce, struct md_entry* src, struct md_entry* dest ) {
    if( src->volume != dest->volume )
       return -EXDEV;
 
@@ -2967,8 +2991,25 @@ int ms_client_rename( struct ms_client* client, struct md_entry* src, struct md_
    struct md_update up;
    ms_client_populate_update( &up, ms::ms_update::RENAME, 0, src );
    memcpy( &up.dest, dest, sizeof(struct md_entry) );
+
+   ms::ms_reply reply;
 
-   return ms_client_file_post( client, &up, NULL );
+   int rc = ms_client_file_post( client, &up, &reply );
+
+   if( rc == 0 ) {
+      // got back a write nonce??
+      if( reply.listing().entries_size() > 0 ) {
+
+         *write_nonce = reply.listing().entries(0).write_nonce();
+
+         dbprintf("New write_nonce of %" PRIx64 " is %" PRId64 "\n", src->file_id, *write_nonce );
+      }
+      else {
+         rc = -ENODATA;
+      }
+   }
+
+   return rc;
 }
 
 // send a batch of updates.

libsyndicate/ms-client.h

@@ -324,13 +324,13 @@ int ms_client_view_unlock2( struct ms_client* client, char const* from_str, int
 
 // file metadata API
 uint64_t ms_client_make_file_id();
-int ms_client_create( struct ms_client* client, uint64_t* file_id, struct md_entry* ent );
-int ms_client_mkdir( struct ms_client* client, uint64_t* file_id, struct md_entry* ent );
+int ms_client_create( struct ms_client* client, uint64_t* file_id, int64_t* write_nonce, struct md_entry* ent );
+int ms_client_mkdir( struct ms_client* client, uint64_t* file_id, int64_t* write_nonce, struct md_entry* ent );
 int ms_client_delete( struct ms_client* client, struct md_entry* ent );
-int ms_client_update_write( struct ms_client* client, struct md_entry* ent, uint64_t* affected_blocks, size_t num_affected_blocks );
-int ms_client_update( struct ms_client* client, struct md_entry* ent );
-int ms_client_coordinate( struct ms_client* client, uint64_t* new_coordinator, struct md_entry* ent );
-int ms_client_rename( struct ms_client* client, struct md_entry* src, struct md_entry* dest );
+int ms_client_update_write( struct ms_client* client, int64_t* write_nonce, struct md_entry* ent, uint64_t* affected_blocks, size_t num_affected_blocks );
+int ms_client_update( struct ms_client* client, int64_t* write_nonce, struct md_entry* ent );
+int ms_client_coordinate( struct ms_client* client, uint64_t* new_coordinator, int64_t* write_nonce, struct md_entry* ent );
+int ms_client_rename( struct ms_client* client, int64_t* write_nonce, struct md_entry* src, struct md_entry* dest );
 
 // xattr API
 int ms_client_getxattr( struct ms_client* client, uint64_t volume_id, uint64_t file_id, char const* xattr_name, char** xattr_value, size_t* xattr_value_len );