dircache.h File Reference

#include <sys/types.h>
#include <atalk/directory.h>
#include <atalk/volume.h>

Go to the source code of this file.

Macros
#define	MAX_POSSIBLE_DIRCACHE_SIZE   131072
#define	DIRCACHE_FREE_QUANTUM   256
#define	DIRCACHE   (1 << 0)
#define	DIDNAME_INDEX   (1 << 1)
#define	QUEUE_INDEX   (1 << 2)
#define	DIRCACHE_ALL   (DIRCACHE|DIDNAME_INDEX|QUEUE_INDEX)

Functions
int	dircache_init (int reqsize)
	Initialize the dircache and indexes.
int	dircache_add (const struct vol *, struct dir *)
	create struct dir from struct path
void	dircache_remove (const struct vol *, struct dir *, int flag)
struct dir *	dircache_search_by_did (const struct vol *vol, cnid_t did)
	Search the dircache via a CNID for a directory.
struct dir *	dircache_search_by_name (const struct vol *, const struct dir *dir, char *name, int len)
	Search the cache via did/name hashtable.
void	dircache_dump (void)
	Dump dircache to /tmp/dircache.PID.
void	log_dircache_stat (void)
	Log dircache statistics.
int	dircache_set_validation_params (unsigned int freq, unsigned int meta_win, unsigned int meta_thresh)
	Set directory cache validation parameters.
void	dircache_reset_validation_counter (void)
	Reset validation counter for consistent testing.
void	dircache_report_invalid_entry (struct dir *dir)
	Report that a cache entry was invalid when actually used.
void	dircache_remove_children (const struct vol *vol, struct dir *dir)
	Remove all child entries of a directory from the dircache.

Macro Definition Documentation

DIDNAME_INDEX

#define DIDNAME_INDEX   (1 << 1)

DIRCACHE

#define DIRCACHE   (1 << 0)

DIRCACHE_ALL

#define DIRCACHE_ALL   (DIRCACHE|DIDNAME_INDEX|QUEUE_INDEX)

DIRCACHE_FREE_QUANTUM

#define DIRCACHE_FREE_QUANTUM   256

MAX_POSSIBLE_DIRCACHE_SIZE

#define MAX_POSSIBLE_DIRCACHE_SIZE   131072

QUEUE_INDEX

#define QUEUE_INDEX   (1 << 2)

Function Documentation

dircache_add()

int dircache_add ( const struct vol * vol, struct dir * dir )

extern

create struct dir from struct path

Add a struct dir to the cache and its indexes.

Parameters

vol	(r) pointer to volume
dir	(r) pointer to parent directory

Returns

0 on success, -1 on error which should result in an abort

dircache_dump()

void dircache_dump ( void )

extern

Dump dircache to /tmp/dircache.PID.

dircache_init()

int dircache_init ( int reqsize )

extern

Initialize the dircache and indexes.

This is called in child afpd initialization. The maximum cache size will be max(DEFAULT_MAX_DIRCACHE_SIZE, min(size, MAX_POSSIBLE_DIRCACHE_SIZE)). It initializes a hashtable which we use to store a directory cache in. It also initializes two indexes:

• a DID/name index on the main dircache
• a queue index on the dircache

Parameters

reqsize

(r) requested maximum size from afp.conf

Returns

0 on success, -1 on error

dircache_remove()

void dircache_remove ( const struct vol * , struct dir * , int flag )

extern

dircache_remove_children()

void dircache_remove_children ( const struct vol * vol, struct dir * dir )

extern

Remove all child entries of a directory from the dircache.

When a directory is renamed or moved, the full paths stored in the dircache become invalid for all child entries of the renamed dir. This function prunes orphaned child dircache entries of given dir. CNID entries use parent DIDs and name, and requre recursion to get the full path, therefore parent changes do not invalidate the CNIDs.

Parameters

vol	(r) volume
dir	(r) parent directory whose children should be removed

dircache_report_invalid_entry()

void dircache_report_invalid_entry ( struct dir * dir )

extern

Report that a cache entry was invalid when actually used.

This function should be called when a cached directory entry that was returned without validation (for performance) turns out to be invalid when actually accessed (e.g., file doesn't exist, has been modified, etc). This helps track the effectiveness of the validation frequency setting.

Parameters

dir	(r) The directory entry that was found to be invalid

dircache_reset_validation_counter()

void dircache_reset_validation_counter ( void )

extern

Reset validation counter for consistent testing.

Resets the global validation counter to ensure predictable validation patterns between test runs or configuration changes.

dircache_search_by_did()

struct dir * dircache_search_by_did ( const struct vol * vol, cnid_t cnid )

extern

Search the dircache via a CNID for a directory.

Found cache entries are expunged if both the parent directory st_ctime and the objects st_ctime are modified. This func builds on the fact, that all our code only ever needs to and does search the dircache by CNID expecting directories to be returned, but not files. Thus (1) if we find a file for a given CNID we (1a) remove it from the cache (1b) return NULL indicating nothing found (2) we can then use d_fullpath to stat the directory

Parameters

vol	(r) pointer to struct vol
cnid	(r) CNID of the directory to search

Returns

Pointer to struct dir if found, else NULL

dircache_search_by_name()

struct dir * dircache_search_by_name ( const struct vol * vol, const struct dir * dir, char * name, int len )

extern

Search the cache via did/name hashtable.

Found cache entries are expunged if both the parent directory st_ctime and the objects st_ctime are modified.

Parameters

vol	(r) volume
dir	(r) directory
name	(r) name (server side encoding)
len	(r) strlen of name

Returns

pointer to struct dir if found in cache, else NULL

dircache_set_validation_params()

int dircache_set_validation_params ( unsigned int freq, unsigned int meta_win, unsigned int meta_thresh )

extern

Set directory cache validation parameters.

Allows runtime configuration of cache validation behavior for performance tuning. Lower validation frequency improves performance but may delay detection of external filesystem changes.

Parameters

freq	(r) validation frequency (1 = validate every access, 5 = every 5th access)
meta_win	(r) metadata change time window in seconds
meta_thresh	(r) metadata change threshold in seconds

Returns

0 on success, -1 on invalid parameters

log_dircache_stat()

void log_dircache_stat ( void )

extern

Log dircache statistics.

Includes hit ratio percentage for monitoring cache effectiveness, validation-specific metrics to monitor performance impact of the optimization changes, and username for tracking per-user stats. Shows both expunged (caught by validation) and invalid_on_use (missed by validation).