From: Martin Mares <mj@ucw.cz>
Date: Mon, 15 Nov 1999 10:31:01 +0000 (+0000)
Subject: Implemented pgc_get_zero().
X-Git-Tag: holmes-import~1649
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=302d2509b53224e828558f3f328be444adee77d6;p=libucw.git

Implemented pgc_get_zero().
---

diff --git a/lib/pagecache.c b/lib/pagecache.c
index 871babe3..67c1e713 100644
--- a/lib/pagecache.c
+++ b/lib/pagecache.c
@@ -278,6 +278,21 @@ pgc_get(struct page_cache *c, int fd, sh_off_t pos)
   return p;
 }
 
+struct page *
+pgc_get_zero(struct page_cache *c, int fd, sh_off_t pos)
+{
+  sh_off_t key;
+  struct page *p;
+
+  ASSERT(!PAGE_OFFSET(pos));
+  ASSERT(!PAGE_NUMBER(fd));
+  key = pos | fd;
+  p = get_and_lock_page(c, key);
+  bzero(p->data, c->page_size);
+  p->flags |= PG_FLAG_VALID | PG_FLAG_DIRTY;
+  return p;
+}
+
 void
 pgc_put(struct page_cache *c, struct page *p)
 {
diff --git a/lib/pagecache.h b/lib/pagecache.h
index 7598f345..0c8b4d67 100644
--- a/lib/pagecache.h
+++ b/lib/pagecache.h
@@ -30,6 +30,7 @@ void pgc_flush(struct page_cache *);				/* Write all unwritten pages */
 void pgc_cleanup(struct page_cache *);				/* Deallocate all unused buffers */
 struct page *pgc_read(struct page_cache *, int fd, sh_off_t);	/* Read page and lock it */
 struct page *pgc_get(struct page_cache *, int fd, sh_off_t);	/* Get page for writing */
+struct page *pgc_get_zero(struct page_cache *, int fd, sh_off_t); /* ... and clear it */
 void pgc_put(struct page_cache *, struct page *);		/* Release page */
 void pgc_mark_dirty(struct page_cache *, struct page *);	/* Mark locked page as dirty */
 byte *pgc_read_data(struct page_cache *, int fd, sh_off_t, uns *);	/* Partial reading */