Commit ddbc22e2 authored by Rasmus Villemoes's avatar Rasmus Villemoes Committed by Linus Torvalds
Browse files

fs/hfs/catalog.c: fix comparison bug in hfs_cat_keycmp 



Relying on the sign (after casting to int) of the difference of two
quantities for comparison is usually wrong.  For example, should a-b
turn out to be 2^31, the return value of cmp(a,b) is -2^31; but that
would also be the return value from cmp(b, a).  So a compares less than
b and b compares less than a.  One can also easily find three values
a,b,c such that a compares less than b, b compares less than c, but a
does not compare less than c.

Signed-off-by: default avatarRasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: default avatarVyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 705304a8

fs/hfs/catalog.c

+8 −6
Original line number Diff line number Diff line
@@ -162,14 +162,16 @@ err2: 
 */

int hfs_cat_keycmp(const btree_key *key1, const btree_key *key2)

{

	int retval;

	__be32 k1p, k2p;



	retval = be32_to_cpu(key1->cat.ParID) - be32_to_cpu(key2->cat.ParID);

	if (!retval)

		retval = hfs_strcmp(key1->cat.CName.name, key1->cat.CName.len,

				    key2->cat.CName.name, key2->cat.CName.len);

	k1p = key1->cat.ParID;

	k2p = key2->cat.ParID;



	if (k1p != k2p)

		return be32_to_cpu(k1p) < be32_to_cpu(k2p) ? -1 : 1;



	return retval;

	return hfs_strcmp(key1->cat.CName.name, key1->cat.CName.len,

			  key2->cat.CName.name, key2->cat.CName.len);

}



/* Try to get a catalog entry for given catalog id */