[Gluster-devel] best practice to ensure data integrity at a concurrent

[Dongmin Yu]

Hello,

 

I’m trying to store additional metadata like content-type and etc at extended attribute.

 

My client code are like

 

fd = glusterfs_open( path );

glusterfs_write( fd, data, data_length );

glusterfs_close( fd );       //------

glusterfs_setxattr( path, attr_name, attr_value, value_length,0 );

 

My concern is that above client code runs on multiple machines and multi-threaded.

In higher concurrency, client A could write content, client B write content, client B write its attribute then client A write its attribute.

So to speak, file content comes from client B but attribute comes from client A.

 

If I use a lock server, I can guarantee data integrity. But is there a simpler way to store extended attributes at an atomic environment?

I see another function, glusterfs_fsetxattr which accepts open glusterfs_file descriptor. If I rewrite as following, can I guarantee the integrity?

 

fd = glusterfs_open( path );

glusterfs_write( fd, data, data_length );

glusterfs_fsetxattr( fd, attr_name, attr_value, value_length,0 );

glusterfs_close( fd );   

 

 

Thanks

 

DongMin Yu

 

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