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authorJeremy Allison <jra@samba.org>2004-08-24 22:48:49 +0000
committerGerald (Jerry) Carter <jerry@samba.org>2007-10-10 10:52:29 -0500
commitfcbb2d3132df36057da73701f7e23f434034e6b0 (patch)
tree557cf0910ad98186f0851ce19abff8c9900e394f /source3/smbd
parent990d9d15db27f47d2a6cac306ab773d42427ade4 (diff)
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r2026: Simplify statcache to use an in-memory tdb. Modify tdb to use
a customer hash function for this tdb (yes it does make a difference on benchmarks). Remove the no longer used hash.c code. Jeremy. (This used to be commit 3fbadac85b8cad89b93d295968e99c38c8677575)
Diffstat (limited to 'source3/smbd')
-rw-r--r--source3/smbd/statcache.c140
1 files changed, 65 insertions, 75 deletions
diff --git a/source3/smbd/statcache.c b/source3/smbd/statcache.c
index 5e78e9a499..07a9e3ca85 100644
--- a/source3/smbd/statcache.c
+++ b/source3/smbd/statcache.c
@@ -26,15 +26,7 @@
Stat cache code used in unix_convert.
*****************************************************************************/
-typedef struct {
- char *original_path;
- char *translated_path;
- size_t translated_path_length;
- char names[2]; /* This is extended via malloc... */
-} stat_cache_entry;
-
-#define INIT_STAT_CACHE_SIZE 512
-static hash_table stat_cache;
+static TDB_CONTEXT *tdb_stat_cache;
/**
* Add an entry into the stat cache.
@@ -50,19 +42,17 @@ static hash_table stat_cache;
void stat_cache_add( const char *full_orig_name, const char *orig_translated_path, BOOL case_sensitive)
{
- stat_cache_entry *scp;
- stat_cache_entry *found_scp;
char *translated_path;
size_t translated_path_length;
-
+ TDB_DATA data_val;
char *original_path;
size_t original_path_length;
- hash_element *hash_elem;
-
if (!lp_stat_cache())
return;
+ ZERO_STRUCT(data_val);
+
/*
* Don't cache trivial valid directory entries such as . and ..
*/
@@ -124,7 +114,7 @@ void stat_cache_add( const char *full_orig_name, const char *orig_translated_pat
return;
}
- /* we only want to store the first part of original_path,
+ /* we only want to index by the first part of original_path,
up to the length of translated_path */
original_path[translated_path_length] = '\0';
@@ -132,55 +122,26 @@ void stat_cache_add( const char *full_orig_name, const char *orig_translated_pat
}
/*
- * Check this name doesn't exist in the cache before we
- * add it.
- */
-
- if ((hash_elem = hash_lookup(&stat_cache, original_path))) {
- found_scp = (stat_cache_entry *)(hash_elem->value);
- if (strcmp((found_scp->translated_path), orig_translated_path) == 0) {
- /* already in hash table */
- SAFE_FREE(original_path);
- SAFE_FREE(translated_path);
- return;
- }
- /* hash collision - remove before we re-add */
- hash_remove(&stat_cache, hash_elem);
- }
-
- /*
- * New entry.
+ * New entry or replace old entry.
*/
- if((scp = (stat_cache_entry *)malloc(sizeof(stat_cache_entry)
- +original_path_length
- +translated_path_length)) == NULL) {
- DEBUG(0,("stat_cache_add: Out of memory !\n"));
- SAFE_FREE(original_path);
- SAFE_FREE(translated_path);
- return;
- }
-
- scp->original_path = scp->names;
- /* pointer into the structure... */
- scp->translated_path = scp->names + original_path_length + 1;
- safe_strcpy(scp->original_path, original_path, original_path_length);
- safe_strcpy(scp->translated_path, translated_path, translated_path_length);
- scp->translated_path_length = translated_path_length;
+ data_val.dsize = translated_path_length + 1;
+ data_val.dptr = translated_path;
- hash_insert(&stat_cache, (char *)scp, original_path);
+ if (tdb_store_bystring(tdb_stat_cache, original_path, data_val, TDB_REPLACE) != 0) {
+ DEBUG(0,("stat_cache_add: Error storing entry %s -> %s\n", original_path, translated_path));
+ } else {
+ DEBUG(5,("stat_cache_add: Added entry (%x:size%x) %s -> %s\n",
+ (unsigned int)data_val.dptr, data_val.dsize, original_path, translated_path));
+ }
SAFE_FREE(original_path);
SAFE_FREE(translated_path);
-
- DEBUG(5,("stat_cache_add: Added entry %s -> %s\n", scp->original_path, scp->translated_path));
}
/**
* Look through the stat cache for an entry
*
- * The hash-table's internals will promote it to the top if found.
- *
* @param conn A connection struct to do the stat() with.
* @param name The path we are attempting to cache, modified by this routine
* to be correct as far as the cache can tell us
@@ -195,11 +156,8 @@ void stat_cache_add( const char *full_orig_name, const char *orig_translated_pat
BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath,
char **start, SMB_STRUCT_STAT *pst)
{
- stat_cache_entry *scp;
char *chk_name;
size_t namelen;
- hash_element *hash_elem;
- char *sp;
BOOL sizechanged = False;
unsigned int num_components = 0;
@@ -244,8 +202,11 @@ BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath,
}
while (1) {
- hash_elem = hash_lookup(&stat_cache, chk_name);
- if(hash_elem == NULL) {
+ TDB_DATA data_val;
+ char *sp;
+
+ data_val = tdb_fetch_bystring(tdb_stat_cache, chk_name);
+ if(data_val.dptr == NULL || data_val.dsize == 0) {
DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n", chk_name ));
/*
* Didn't find it - remove last component for next try.
@@ -275,44 +236,71 @@ BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath,
return False;
}
} else {
- scp = (stat_cache_entry *)(hash_elem->value);
- DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] -> [%s]\n", chk_name, scp->translated_path ));
+ BOOL retval;
+ char *translated_path = data_val.dptr;
+ size_t translated_path_length = data_val.dsize - 1;
+
+ DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] -> [%s]\n", chk_name, translated_path ));
DO_PROFILE_INC(statcache_hits);
- if(SMB_VFS_STAT(conn,scp->translated_path, pst) != 0) {
+ if(SMB_VFS_STAT(conn,translated_path, pst) != 0) {
/* Discard this entry - it doesn't exist in the filesystem. */
- hash_remove(&stat_cache, hash_elem);
+ tdb_delete_bystring(tdb_stat_cache, chk_name);
SAFE_FREE(chk_name);
+ SAFE_FREE(data_val.dptr);
return False;
}
if (!sizechanged) {
- memcpy(name, scp->translated_path, MIN(sizeof(pstring)-1, scp->translated_path_length));
+ memcpy(name, translated_path, MIN(sizeof(pstring)-1, translated_path_length));
} else if (num_components == 0) {
- pstrcpy(name, scp->translated_path);
+ pstrcpy(name, translated_path);
} else {
sp = strnrchr_m(name, '/', num_components);
if (sp) {
pstring last_component;
pstrcpy(last_component, sp);
- pstrcpy(name, scp->translated_path);
+ pstrcpy(name, translated_path);
pstrcat(name, last_component);
} else {
- pstrcpy(name, scp->translated_path);
+ pstrcpy(name, translated_path);
}
}
/* set pointer for 'where to start' on fixing the rest of the name */
- *start = &name[scp->translated_path_length];
+ *start = &name[translated_path_length];
if(**start == '/')
++*start;
- pstrcpy(dirpath, scp->translated_path);
+ pstrcpy(dirpath, translated_path);
+ retval = (namelen == translated_path_length) ? True : False;
SAFE_FREE(chk_name);
- return (namelen == scp->translated_path_length);
+ SAFE_FREE(data_val.dptr);
+ return retval;
}
}
}
+/*
+ **************************************************************
+ * Compute a hash value based on a string key value.
+ * Make the string key into an array of int's if possible.
+ * For the last few chars that cannot be int'ed, use char instead.
+ * The function returns the bucket index number for the hashed
+ * key.
+ * JRA. Use a djb-algorithm hash for speed.
+ **************************************************************
+ */
+
+static u32 string_hash(TDB_DATA *key)
+{
+ u32 n = 0;
+ const char *p;
+ for (p = key->dptr; *p != '\0'; p++) {
+ n = ((n << 5) + n) ^ (u32)(*p);
+ }
+ return n;
+}
+
/*************************************************************************** **
* Initializes or clears the stat cache.
*
@@ -323,15 +311,17 @@ BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath,
*/
BOOL reset_stat_cache( void )
{
- static BOOL initialised;
if (!lp_stat_cache())
return True;
- if (initialised) {
- hash_clear(&stat_cache);
+ if (tdb_stat_cache) {
+ tdb_close(tdb_stat_cache);
}
- initialised = hash_table_init( &stat_cache, INIT_STAT_CACHE_SIZE,
- (compare_function)(strcmp));
- return initialised;
+ /* Create the in-memory tdb. */
+ tdb_stat_cache = tdb_open_log("statcache", 0, TDB_INTERNAL, (O_RDWR|O_CREAT), 0644);
+ if (!tdb_stat_cache)
+ return False;
+ tdb_set_hash_function(tdb_stat_cache, string_hash);
+ return True;
}