diff options
| author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2014-12-10 15:54:37 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-10 17:41:16 -0800 |
| commit | ddbc22e27e672b6b180757ea1d7f8481dbb88128 (patch) | |
| tree | dd1c05913129d4fc065054d275fb5b0112745649 | |
| parent | 705304a863cc41585508c0f476f6d3ec28cf7e00 (diff) | |
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: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/hfs/catalog.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/fs/hfs/catalog.c b/fs/hfs/catalog.c index ff0316b925a5..db458ee3a546 100644 --- a/fs/hfs/catalog.c +++ b/fs/hfs/catalog.c @@ -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; - return retval; + if (k1p != k2p) + return be32_to_cpu(k1p) < be32_to_cpu(k2p) ? -1 : 1; + + 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 */ |