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Diffstat (limited to 'Documentation/filesystems/pohmelfs/network_protocol.txt')
| -rw-r--r-- | Documentation/filesystems/pohmelfs/network_protocol.txt | 227 |
1 files changed, 0 insertions, 227 deletions
diff --git a/Documentation/filesystems/pohmelfs/network_protocol.txt b/Documentation/filesystems/pohmelfs/network_protocol.txt deleted file mode 100644 index c680b4b5353d5..0000000000000 --- a/Documentation/filesystems/pohmelfs/network_protocol.txt +++ /dev/null @@ -1,227 +0,0 @@ -POHMELFS network protocol. - -Basic structure used in network communication is following command: - -struct netfs_cmd -{ - __u16 cmd; /* Command number */ - __u16 csize; /* Attached crypto information size */ - __u16 cpad; /* Attached padding size */ - __u16 ext; /* External flags */ - __u32 size; /* Size of the attached data */ - __u32 trans; /* Transaction id */ - __u64 id; /* Object ID to operate on. Used for feedback.*/ - __u64 start; /* Start of the object. */ - __u64 iv; /* IV sequence */ - __u8 data[0]; -}; - -Commands can be embedded into transaction command (which in turn has own command), -so one can extend protocol as needed without breaking backward compatibility as long -as old commands are supported. All string lengths include tail 0 byte. - -All commands are transferred over the network in big-endian. CPU endianness is used at the end peers. - -@cmd - command number, which specifies command to be processed. Following - commands are used currently: - - NETFS_READDIR = 1, /* Read directory for given inode number */ - NETFS_READ_PAGE, /* Read data page from the server */ - NETFS_WRITE_PAGE, /* Write data page to the server */ - NETFS_CREATE, /* Create directory entry */ - NETFS_REMOVE, /* Remove directory entry */ - NETFS_LOOKUP, /* Lookup single object */ - NETFS_LINK, /* Create a link */ - NETFS_TRANS, /* Transaction */ - NETFS_OPEN, /* Open intent */ - NETFS_INODE_INFO, /* Metadata cache coherency synchronization message */ - NETFS_PAGE_CACHE, /* Page cache invalidation message */ - NETFS_READ_PAGES, /* Read multiple contiguous pages in one go */ - NETFS_RENAME, /* Rename object */ - NETFS_CAPABILITIES, /* Capabilities of the client, for example supported crypto */ - NETFS_LOCK, /* Distributed lock message */ - NETFS_XATTR_SET, /* Set extended attribute */ - NETFS_XATTR_GET, /* Get extended attribute */ - -@ext - external flags. Used by different commands to specify some extra arguments - like partial size of the embedded objects or creation flags. - -@size - size of the attached data. For NETFS_READ_PAGE and NETFS_READ_PAGES no data is attached, - but size of the requested data is incorporated here. It does not include size of the command - header (struct netfs_cmd) itself. - -@id - id of the object this command operates on. Each command can use it for own purpose. - -@start - start of the object this command operates on. Each command can use it for own purpose. - -@csize, @cpad - size and padding size of the (attached if needed) crypto information. - -Command specifications. - -@NETFS_READDIR -This command is used to sync content of the remote dir to the client. - -@ext - length of the path to object. -@size - the same. -@id - local inode number of the directory to read. -@start - zero. - - -@NETFS_READ_PAGE -This command is used to read data from remote server. -Data size does not exceed local page cache size. - -@id - inode number. -@start - first byte offset. -@size - number of bytes to read plus length of the path to object. -@ext - object path length. - - -@NETFS_CREATE -Used to create object. -It does not require that all directories on top of the object were -already created, it will create them automatically. Each object has -associated @netfs_path_entry data structure, which contains creation -mode (permissions and type) and length of the name as long as name itself. - -@start - 0 -@size - size of the all data structures needed to create a path -@id - local inode number -@ext - 0 - - -@NETFS_REMOVE -Used to remove object. - -@ext - length of the path to object. -@size - the same. -@id - local inode number. -@start - zero. - - -@NETFS_LOOKUP -Lookup information about object on server. - -@ext - length of the path to object. -@size - the same. -@id - local inode number of the directory to look object in. -@start - local inode number of the object to look at. - - -@NETFS_LINK -Create hard of symlink. -Command is sent as "object_path|target_path". - -@size - size of the above string. -@id - parent local inode number. -@start - 1 for symlink, 0 for hardlink. -@ext - size of the "object_path" above. - - -@NETFS_TRANS -Transaction header. - -@size - incorporates all embedded command sizes including theirs header sizes. -@start - transaction generation number - unique id used to find transaction. -@ext - transaction flags. Unused at the moment. -@id - 0. - - -@NETFS_OPEN -Open intent for given transaction. - -@id - local inode number. -@start - 0. -@size - path length to the object. -@ext - open flags (O_RDWR and so on). - - -@NETFS_INODE_INFO -Metadata update command. -It is sent to servers when attributes of the object are changed and received -when data or metadata were updated. It operates with the following structure: - -struct netfs_inode_info -{ - unsigned int mode; - unsigned int nlink; - unsigned int uid; - unsigned int gid; - unsigned int blocksize; - unsigned int padding; - __u64 ino; - __u64 blocks; - __u64 rdev; - __u64 size; - __u64 version; -}; - -It effectively mirrors stat(2) returned data. - - -@ext - path length to the object. -@size - the same plus size of the netfs_inode_info structure. -@id - local inode number. -@start - 0. - - -@NETFS_PAGE_CACHE -Command is only received by clients. It contains information about -page to be marked as not up-to-date. - -@id - client's inode number. -@start - last byte of the page to be invalidated. If it is not equal to - current inode size, it will be vmtruncated(). -@size - 0 -@ext - 0 - - -@NETFS_READ_PAGES -Used to read multiple contiguous pages in one go. - -@start - first byte of the contiguous region to read. -@size - contains of two fields: lower 8 bits are used to represent page cache shift - used by client, another 3 bytes are used to get number of pages. -@id - local inode number. -@ext - path length to the object. - - -@NETFS_RENAME -Used to rename object. -Attached data is formed into following string: "old_path|new_path". - -@id - local inode number. -@start - parent inode number. -@size - length of the above string. -@ext - length of the old path part. - - -@NETFS_CAPABILITIES -Used to exchange crypto capabilities with server. -If crypto capabilities are not supported by server, then client will disable it -or fail (if 'crypto_fail_unsupported' mount options was specified). - -@id - superblock index. Used to specify crypto information for group of servers. -@size - size of the attached capabilities structure. -@start - 0. -@size - 0. -@scsize - 0. - -@NETFS_LOCK -Used to send lock request/release messages. Although it sends byte range request -and is capable of flushing pages based on that, it is not used, since all Linux -filesystems lock the whole inode. - -@id - lock generation number. -@start - start of the locked range. -@size - size of the locked range. -@ext - lock type: read/write. Not used actually. 15'th bit is used to determine, - if it is lock request (1) or release (0). - -@NETFS_XATTR_SET -@NETFS_XATTR_GET -Used to set/get extended attributes for given inode. -@id - attribute generation number or xattr setting type -@start - size of the attribute (request or attached) -@size - name length, path len and data size for given attribute -@ext - path length for given object |