summaryrefslogtreecommitdiffstats
path: root/Documentation/filesystems/pohmelfs/network_protocol.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/filesystems/pohmelfs/network_protocol.txt')
-rw-r--r--Documentation/filesystems/pohmelfs/network_protocol.txt227
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 c680b4b..0000000
--- 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