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 <[email protected]>
Cc: George Spelvin <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Linus Torvalds 2016-06-10 07:51:30 -07:00
commit 8387ff2577
38 changed files with 99 additions and 89 deletions

View file

@ -61,7 +61,7 @@ affs_get_toupper(struct super_block *sb)
* Note: the dentry argument is the parent dentry.
*/
static inline int
__affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)
__affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr, toupper_t toupper, bool notruncate)
{
const u8 *name = qstr->name;
unsigned long hash;
@ -72,7 +72,7 @@ __affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)
if (retval)
return retval;
hash = init_name_hash();
hash = init_name_hash(dentry);
len = min(qstr->len, AFFSNAMEMAX);
for (; len > 0; name++, len--)
hash = partial_name_hash(toupper(*name), hash);
@ -84,7 +84,7 @@ __affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)
static int
affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
{
return __affs_hash_dentry(qstr, affs_toupper,
return __affs_hash_dentry(dentry, qstr, affs_toupper,
affs_nofilenametruncate(dentry));
}
@ -92,7 +92,7 @@ affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
static int
affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
{
return __affs_hash_dentry(qstr, affs_intl_toupper,
return __affs_hash_dentry(dentry, qstr, affs_intl_toupper,
affs_nofilenametruncate(dentry));
}