Add has_ref to help debugging.

It is sometimes helpful to BUG_ON whether a block has a certain
ref or not.
So add "has_ref" which returns -1 if we don't know (debugging
disabled) or  0/1 depending on whether ref is held.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/block.c b/block.c
index d0c968789899716b7f91fadd337942210d14441e..19509cd3c62f9e5d54de51d13d212a969cf0a4d0 100644 (file)
--- a/block.c
+++ b/block.c
@@ -66,6 +66,18 @@ void del_ref(struct block *b, char *ref, char *file, int line)
               ref, file, line, strblk(b));
        BUG();
 }
+
+int has_ref(struct block *b, char *ref)
+{
+       int i;
+       spin_lock(&refl);
+       for (i = 0; i < 16; i++)
+               if (b->holders[i].cnt &&
+                   strcmp(b->holders[i].name, ref) == 0)
+                       break;
+       spin_unlock(&refl);
+       return i < 16;
+}
 #endif
 
 /* Based on grow_dev_page */

diff --git a/lafs.h b/lafs.h
index 27de449599ba881aa1e3d4adbafcc9933f6e76b4..1408c97db7b020e29b512c9ac26e076caecf775a 100644 (file)
--- a/lafs.h
+++ b/lafs.h
@@ -34,6 +34,7 @@ extern void lafs_dump_tree(void);
 
 #define add_ref(a,b,c,d) lafs_add_ref(a,b,c,d)
 #define del_ref(a,b,c,d) lafs_del_ref(a,b,c,d)
+#define has_ref(a,b) lafs_has_ref(a,b)
 
 #define lafs_get_block(a,b,c,d,e) _lafs_get_block(a,b,c,d,e)
 #define first_in_seg(a,b,c,d,e) _first_in_seg(a,b,c,d,e)
@@ -52,6 +53,7 @@ extern void lafs_dump_tree(void);
 
 #define add_ref(a,b,c,d) do {} while (0)
 #define del_ref(a,b,c,d) do {} while (0)
+#define has_ref(a,b) (-1)
 
 #define lafs_get_block(a,b,c,d,e) _lafs_get_block(a,b,c,d)
 #define first_in_seg(a,b,c,d,e) _first_in_seg(a,b,c,d)
@@ -153,6 +155,7 @@ struct datablock *lafs_get_block(struct inode *ino, unsigned long index,
 #if DEBUG_REF
 void add_ref(struct block *b, char *ref, char *file, int line);
 void del_ref(struct block *b, char *ref, char *file, int line);
+int has_ref(struct block *b, char *ref);
 #endif
 
 int lafs_setattr(struct dentry *dentry, struct iattr *attr);