ceph: capability management

Browse Source

The Ceph metadata servers control client access to inode metadata and
file data by issuing capabilities, granting clients permission to read
and/or write both inode field and file data to OSDs (storage nodes).
Each capability consists of a set of bits indicating which operations
are allowed.

If the client holds a *_SHARED cap, the client has a coherent value
that can be safely read from the cached inode.

In the case of a *_EXCL (exclusive) or FILE_WR capabilities, the client
is allowed to change inode attributes (e.g., file size, mtime), note
its dirty state in the ceph_cap, and asynchronously flush that
metadata change to the MDS.

In the event of a conflicting operation (perhaps by another client),
the MDS will revoke the conflicting client capabilities.

In order for a client to cache an inode, it must hold a capability
with at least one MDS server.  When inodes are released, release
notifications are batched and periodically sent en masse to the MDS
cluster to release server state.

Signed-off-by: Sage Weil <sage@newdream.net>

...

This commit is contained in:

Sage Weil 2009-10-06 11:31:12 -07:00

parent ba75bb98cf

commit a8599bd821

1 changed files with 2830 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2830

fs/ceph/caps.c Normal file

View File

File diff suppressed because it is too large Load Diff