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Extend generic dirhash to include an empty directory checker based on 

the knowledge the dirhash has. This is done by keeping a count of the current
hash entries.
This commit is contained in:
reinoud 2013-07-07 19:31:26 +00:00
parent 7716d8c63e
commit 8fd5b25064
2 changed files with 39 additions and 3 deletions
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38
sys/kern/vfs_dirhash.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: vfs_dirhash.c,v 1.10 2009/02/06 23:56:26 enami Exp $ */
/* $NetBSD: vfs_dirhash.c,v 1.11 2013/07/07 19:31:26 reinoud Exp $ */
/*
* Copyright (c) 2008 Reinoud Zandijk
@ -28,7 +28,7 @@
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_dirhash.c,v 1.10 2009/02/06 23:56:26 enami Exp $");
__KERNEL_RCSID(0, "$NetBSD: vfs_dirhash.c,v 1.11 2013/07/07 19:31:26 reinoud Exp $");
/* CLEAN UP! */
#include <sys/param.h>
@ -165,6 +165,7 @@ dirhash_purge_entries(struct dirhash *dirh)
dirh->flags &= ~DIRH_COMPLETE;
dirh->flags |= DIRH_PURGED;
dirh->num_files = 0;
dirhashsize -= dirh->size;
dirh->size = 0;
@ -309,6 +310,7 @@ dirhash_enter(struct dirhash *dirh,
dirh_e->entry_size = entry_size;
dirh->size += sizeof(struct dirhash_entry);
dirh->num_files++;
dirhashsize += sizeof(struct dirhash_entry);
LIST_INSERT_HEAD(&dirh->entries[hashline], dirh_e, next);
}
@ -378,6 +380,8 @@ dirhash_remove(struct dirhash *dirh, struct dirent *dirent,
KASSERT(dirh_e->entry_size == entry_size);
LIST_REMOVE(dirh_e, next);
dirh->size -= sizeof(struct dirhash_entry);
KASSERT(dirh->num_files > 0);
dirh->num_files--;
dirhashsize -= sizeof(struct dirhash_entry);
dirhash_enter_freed(dirh, offset, entry_size);
@ -469,3 +473,33 @@ dirhash_lookup_freed(struct dirhash *dirh, uint32_t min_entrysize,
*result = NULL;
return 0;
}
bool
dirhash_dir_isempty(struct dirhash *dirh)
{
#ifdef DEBUG
struct dirhash_entry *dirh_e;
int hashline, num;
num = 0;
for (hashline = 0; hashline < DIRHASH_HASHSIZE; hashline++) {
LIST_FOREACH(dirh_e, &dirh->entries[hashline], next) {
num++;
}
}
if (dirh->num_files != num) {
printf("dirhash_dir_isempy: dirhash_counter failed: "
"dirh->num_files = %d, counted %d\n",
dirh->num_files, num);
assert(dirh->num_files == num);
}
#endif
/* assert the directory hash info is valid */
KASSERT(dirh->flags & DIRH_COMPLETE);
/* the directory is empty when only '..' lifes in it or is absent */
return (dirh->num_files <= 1);
}

4
sys/sys/dirhash.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: dirhash.h,v 1.5 2009/09/27 21:50:48 reinoud Exp $ */
/* $NetBSD: dirhash.h,v 1.6 2013/07/07 19:31:26 reinoud Exp $ */
/*
* Copyright (c) 2008 Reinoud Zandijk
@ -52,6 +52,7 @@ struct dirhash {
uint32_t flags;
uint32_t size; /* in bytes */
uint32_t refcnt;
uint32_t num_files;
LIST_HEAD(, dirhash_entry) entries[DIRHASH_HASHSIZE];
LIST_HEAD(, dirhash_entry) free_entries;
TAILQ_ENTRY(dirhash) next;
@ -79,5 +80,6 @@ int dirhash_lookup(struct dirhash *, const char *, int,
struct dirhash_entry **);
int dirhash_lookup_freed(struct dirhash *, uint32_t,
struct dirhash_entry **);
bool dirhash_dir_isempty(struct dirhash *dirh);
#endif /* _SYS_DIRHASH_H_ */