alistair23-linux/fs/afs/afs.h
David Howells be080a6f43 afs: Overhaul permit caching
Overhaul permit caching in AFS by making it per-vnode and sharing permit
lists where possible.

When most of the fileserver operations are called, they return a status
structure indicating the (revised) details of the vnode or vnodes involved
in the operation.  This includes the access mark derived from the ACL
(named CallerAccess in the protocol definition file).  This is cacheable
and if the ACL changes, the server will tell us that it is breaking the
callback promise, at which point we can discard the currently cached
permits.

With this patch, the afs_permits structure has, at the end, an array of
{ key, CallerAccess } elements, sorted by key pointer.  This is then cached
in a hash table so that it can be shared between vnodes with the same
access permits.

Permit lists can only be shared if they contain the exact same set of
key->CallerAccess mappings.

Note that that table is global rather than being per-net_ns.  If the keys
in a permit list cross net_ns boundaries, there is no problem sharing the
cached permits, since the permits are just integer masks.

Since permit lists pin keys, the permit cache also makes it easier for a
future patch to find all occurrences of a key and remove them by means of
setting the afs_permits::invalidated flag and then clearing the appropriate
key pointer.  In such an event, memory barriers will need adding.

Lastly, the permit caching is skipped if the server has sent either a
vnode-specific or an entire-server callback since the start of the
operation.

Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-13 15:38:18 +00:00

194 lines
6.5 KiB
C

/* AFS common types
*
* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef AFS_H
#define AFS_H
#include <linux/in.h>
#define AFS_MAXCELLNAME 64 /* Maximum length of a cell name */
#define AFS_MAXVOLNAME 64 /* Maximum length of a volume name */
#define AFS_MAXNSERVERS 8 /* Maximum servers in a basic volume record */
#define AFS_NMAXNSERVERS 13 /* Maximum servers in a N/U-class volume record */
#define AFS_MAXTYPES 3 /* Maximum number of volume types */
#define AFSNAMEMAX 256 /* Maximum length of a filename plus NUL */
#define AFSPATHMAX 1024 /* Maximum length of a pathname plus NUL */
#define AFSOPAQUEMAX 1024 /* Maximum length of an opaque field */
typedef unsigned afs_volid_t;
typedef unsigned afs_vnodeid_t;
typedef unsigned long long afs_dataversion_t;
typedef enum {
AFSVL_RWVOL, /* read/write volume */
AFSVL_ROVOL, /* read-only volume */
AFSVL_BACKVOL, /* backup volume */
} __attribute__((packed)) afs_voltype_t;
typedef enum {
AFS_FTYPE_INVALID = 0,
AFS_FTYPE_FILE = 1,
AFS_FTYPE_DIR = 2,
AFS_FTYPE_SYMLINK = 3,
} afs_file_type_t;
typedef enum {
AFS_LOCK_READ = 0, /* read lock request */
AFS_LOCK_WRITE = 1, /* write lock request */
} afs_lock_type_t;
#define AFS_LOCKWAIT (5 * 60) /* time until a lock times out (seconds) */
/*
* AFS file identifier
*/
struct afs_fid {
afs_volid_t vid; /* volume ID */
afs_vnodeid_t vnode; /* file index within volume */
unsigned unique; /* unique ID number (file index version) */
};
/*
* AFS callback notification
*/
typedef enum {
AFSCM_CB_UNTYPED = 0, /* no type set on CB break */
AFSCM_CB_EXCLUSIVE = 1, /* CB exclusive to CM [not implemented] */
AFSCM_CB_SHARED = 2, /* CB shared by other CM's */
AFSCM_CB_DROPPED = 3, /* CB promise cancelled by file server */
} afs_callback_type_t;
struct afs_callback {
struct afs_fid fid; /* file identifier */
unsigned version; /* callback version */
unsigned expiry; /* time at which expires */
afs_callback_type_t type; /* type of callback */
};
#define AFSCBMAX 50 /* maximum callbacks transferred per bulk op */
struct afs_uuid {
__be32 time_low; /* low part of timestamp */
__be16 time_mid; /* mid part of timestamp */
__be16 time_hi_and_version; /* high part of timestamp and version */
__s8 clock_seq_hi_and_reserved; /* clock seq hi and variant */
__s8 clock_seq_low; /* clock seq low */
__s8 node[6]; /* spatially unique node ID (MAC addr) */
};
/*
* AFS volume information
*/
struct afs_volume_info {
afs_volid_t vid; /* volume ID */
afs_voltype_t type; /* type of this volume */
afs_volid_t type_vids[5]; /* volume ID's for possible types for this vol */
/* list of fileservers serving this volume */
size_t nservers; /* number of entries used in servers[] */
struct {
struct in_addr addr; /* fileserver address */
} servers[8];
};
/*
* AFS security ACE access mask
*/
typedef u32 afs_access_t;
#define AFS_ACE_READ 0x00000001U /* - permission to read a file/dir */
#define AFS_ACE_WRITE 0x00000002U /* - permission to write/chmod a file */
#define AFS_ACE_INSERT 0x00000004U /* - permission to create dirent in a dir */
#define AFS_ACE_LOOKUP 0x00000008U /* - permission to lookup a file/dir in a dir */
#define AFS_ACE_DELETE 0x00000010U /* - permission to delete a dirent from a dir */
#define AFS_ACE_LOCK 0x00000020U /* - permission to lock a file */
#define AFS_ACE_ADMINISTER 0x00000040U /* - permission to change ACL */
#define AFS_ACE_USER_A 0x01000000U /* - 'A' user-defined permission */
#define AFS_ACE_USER_B 0x02000000U /* - 'B' user-defined permission */
#define AFS_ACE_USER_C 0x04000000U /* - 'C' user-defined permission */
#define AFS_ACE_USER_D 0x08000000U /* - 'D' user-defined permission */
#define AFS_ACE_USER_E 0x10000000U /* - 'E' user-defined permission */
#define AFS_ACE_USER_F 0x20000000U /* - 'F' user-defined permission */
#define AFS_ACE_USER_G 0x40000000U /* - 'G' user-defined permission */
#define AFS_ACE_USER_H 0x80000000U /* - 'H' user-defined permission */
/*
* AFS file status information
*/
struct afs_file_status {
unsigned if_version; /* interface version */
#define AFS_FSTATUS_VERSION 1
afs_file_type_t type; /* file type */
unsigned nlink; /* link count */
u64 size; /* file size */
afs_dataversion_t data_version; /* current data version */
u32 author; /* author ID */
kuid_t owner; /* owner ID */
kgid_t group; /* group ID */
afs_access_t caller_access; /* access rights for authenticated caller */
afs_access_t anon_access; /* access rights for unauthenticated caller */
umode_t mode; /* UNIX mode */
time_t mtime_client; /* last time client changed data */
time_t mtime_server; /* last time server changed data */
s32 lock_count; /* file lock count (0=UNLK -1=WRLCK +ve=#RDLCK */
};
/*
* AFS file status change request
*/
#define AFS_SET_MTIME 0x01 /* set the mtime */
#define AFS_SET_OWNER 0x02 /* set the owner ID */
#define AFS_SET_GROUP 0x04 /* set the group ID (unsupported?) */
#define AFS_SET_MODE 0x08 /* set the UNIX mode */
#define AFS_SET_SEG_SIZE 0x10 /* set the segment size (unsupported) */
/*
* AFS volume synchronisation information
*/
struct afs_volsync {
time_t creation; /* volume creation time */
};
/*
* AFS volume status record
*/
struct afs_volume_status {
u32 vid; /* volume ID */
u32 parent_id; /* parent volume ID */
u8 online; /* true if volume currently online and available */
u8 in_service; /* true if volume currently in service */
u8 blessed; /* same as in_service */
u8 needs_salvage; /* true if consistency checking required */
u32 type; /* volume type (afs_voltype_t) */
u32 min_quota; /* minimum space set aside (blocks) */
u32 max_quota; /* maximum space this volume may occupy (blocks) */
u32 blocks_in_use; /* space this volume currently occupies (blocks) */
u32 part_blocks_avail; /* space available in volume's partition */
u32 part_max_blocks; /* size of volume's partition */
};
#define AFS_BLOCK_SIZE 1024
/*
* XDR encoding of UUID in AFS.
*/
struct afs_uuid__xdr {
__be32 time_low;
__be32 time_mid;
__be32 time_hi_and_version;
__be32 clock_seq_hi_and_reserved;
__be32 clock_seq_low;
__be32 node[6];
};
#endif /* AFS_H */