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linux/fs/afs/afs.h
David Howells 16069e1349 afs: Parse the VolSync record in the reply of a number of RPC ops 
A number of fileserver RPC operations return a VolSync record as part of
their reply that gives some information about the state of the volume being
accessed, including:

 (1) A volume Creation timestamp.  For an RW volume, this is the time at
     which the volume was created; if it changes, the RW volume was
     presumably restored from a backup and all cached data should be
     scrubbed as Data Version numbers could regress on the files in the
     volume.

     For an RO volume, this is the time it was last snapshotted from the RW
     volume.  It is expected to advance each time this happens; if it
     regresses, cached data should be scrubbed.

 (2) A volume Update timestamp (Auristor only).  For an RW volume, this is
     updated any time any change is made to a volume or its contents.  If
     it regresses, all cached data must be scrubbed.

     For an RO volume, this is a copy of the RW volume's Update timestamp
     at the point of snapshotting.  It can be used as a version number when
     checking to see if a callback on a RO volume was due to a snapshot.
     If it regresses, all cached data must be scrubbed.

but this is currently not made use of by the in-kernel afs filesystem.

Make the afs filesystem use this by:

 (1) Add an update time field to the afs_volsync struct and use a value of
     TIME64_MIN in both that and the creation time to indicate that they
     are unset.

 (2) Add creation and update time fields to the afs_volume struct and use
     this to track the two timestamps.

 (3) Add a volsync_lock mutex to the afs_volume struct to control
     modification access for when we detect a change in these values.

 (3) Add a 'pre-op volsync' struct to the afs_operation struct to record
     the state of the volume tracking before the op.

 (4) Add a new counter, cb_scrub, to the afs_volume struct to count events
     that require all data to be scrubbed.  A copy is placed in the
     afs_vnode struct (inode) and if they no longer match, a scrub takes
     place.

 (5) When the result of an operation is being parsed, parse the VolSync
     data too, if it is provided.  Note that the two timestamps are handled
     separately, since they don't work in quite the same way.

     - If the afs_volume tracking is unset, just set it and do nothing
       else.

     - If the result timestamps are the same as the ones in afs_volume, do
       nothing.

     - If the timestamps regress, increment cb_scrub if not already done
       so.

     - If the creation timestamp on a RW volume changes, increment cb_scrub
       if not already done so.

     - If the creation timestamp on a RO volume advances, update the server
       list and see if the current server has been excluded, if so reissue
       the op.  Once over half of the replication sites have been updated,
       increment cb_ro_snapshot to indicate updates may be required and
       switch over to excluding unupdated replication sites.

     - If the creation timestamp on a Backup volume advances, just
       increment cb_ro_snapshot to trigger updates.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2024-01-01 16:37:27 +00:00

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* AFS common types
*
* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifndef AFS_H
#define AFS_H
#include <linux/in.h>
#define AFS_MAXCELLNAME 256 /* 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 */
#define AFS_VL_MAX_LIFESPAN 120
#define AFS_PROBE_MAX_LIFESPAN 30
typedef u64 afs_volid_t;
typedef u64 afs_vnodeid_t;
typedef u64 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; /* Lower 64-bits of file index within volume */
u32 vnode_hi; /* Upper 32-bits of file index */
u32 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 {
time64_t expires_at; /* Time at which expires */
//unsigned version; /* Callback version */
//afs_callback_type_t type; /* Type of callback */
};
struct afs_callback_break {
struct afs_fid fid; /* File identifier */
//struct afs_callback cb; /* Callback details */
};
#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 {
u64 size; /* file size */
afs_dataversion_t data_version; /* current data version */
struct timespec64 mtime_client; /* Last time client changed data */
struct timespec64 mtime_server; /* Last time server changed data */
s64 author; /* author ID */
s64 owner; /* owner ID */
s64 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 */
afs_file_type_t type; /* file type */
u32 nlink; /* link count */
s32 lock_count; /* file lock count (0=UNLK -1=WRLCK +ve=#RDLCK */
u32 abort_code; /* Abort if bulk-fetching this failed */
};
struct afs_status_cb {
struct afs_file_status status;
struct afs_callback callback;
bool have_status; /* True if status record was retrieved */
bool have_cb; /* True if cb record was retrieved */
bool have_error; /* True if status.abort_code indicates an error */
};
/*
* 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 {
time64_t creation; /* Volume creation time (or TIME64_MIN) */
time64_t update; /* Volume update time (or TIME64_MIN) */
};
/*
* AFS volume status record
*/
struct afs_volume_status {
afs_volid_t vid; /* volume ID */
afs_volid_t 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) */
u64 min_quota; /* minimum space set aside (blocks) */
u64 max_quota; /* maximum space this volume may occupy (blocks) */
u64 blocks_in_use; /* space this volume currently occupies (blocks) */
u64 part_blocks_avail; /* space available in volume's partition */
u64 part_max_blocks; /* size of volume's partition */
s64 vol_copy_date;
s64 vol_backup_date;
};
#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 */
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