I am investigating the problem of supporting a samba server's granting of OpLocks to its clients when the files that the samba serving is accessing are in a clustered file system. A samba server running in linux determines whether and what kind of OpLock (i.e. either shared or exclusive) to grant to its clients for a particular file, by establishing a corresponding lease on the file in question. This works well for single host based file systems (e.g. ext3, etc.) but does not work at all for distributed or clustered file systems. This is because the vfs running on the same node where the samba server is running is not necessarily aware of all accesses to the file on which it is granting a lease. Since vfs does not currently inform file systems about the granting and rescinding of leases, a clustered file system cannot allow a samba server to support OpLocks on its files and this has a negative impact on performance. What I think is needed is to add a file systems defined file_operations function, that would be invoked when vfs is considering the granting of a lease on a file associated with an inode. Such an enhancement would allow a file system to be come aware of vfs lease activity and allow it to support this activity. I would like to know if there has been any work done in this area and if so, are there people with whom I could correspond to help me work this out. I am fairly new to this area and would appreciate any help that I can get. Thanks. - Robert Rappaport - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
