vfs: make the string hashes salt the hash

We always mixed in the parent pointer into the dentry name hash, but we
did it late at lookup time.  It turns out that we can simplify that
lookup-time action by salting the hash with the parent pointer early
instead of late.

A few other users of our string hashes also wanted to mix in their own
pointers into the hash, and those are updated to use the same mechanism.

Hash users that don't have any particular initial salt can just use the
NULL pointer as a no-salt.

Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: George Spelvin <linux@sciencehorizons.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 3 insertions, 3 deletions

diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index b7e2b33..1337c0c 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -154,7 +154,7 @@ static int msdos_hash(const struct dentry *dentry, struct qstr *qstr)
 
 	error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
 	if (!error)
-		qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
+		qstr->hash = full_name_hash(dentry, msdos_name, MSDOS_NAME);
 	return 0;
 }
 
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 7092584..6ccdf3f 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -107,7 +107,7 @@ static unsigned int vfat_striptail_len(const struct qstr *qstr)
  */
 static int vfat_hash(const struct dentry *dentry, struct qstr *qstr)
 {
-	qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr));
+	qstr->hash = full_name_hash(dentry, qstr->name, vfat_striptail_len(qstr));
 	return 0;
 }
 
@@ -127,7 +127,7 @@ static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr)
 	name = qstr->name;
 	len = vfat_striptail_len(qstr);
 
-	hash = init_name_hash();
+	hash = init_name_hash(dentry);
 	while (len--)
 		hash = partial_name_hash(nls_tolower(t, *name++), hash);
 	qstr->hash = end_name_hash(hash);