From 26fe575028703948880fce4355a210c76bb0536e Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 10 May 2012 13:14:12 -0700 Subject: vfs: make it possible to access the dentry hash/len as one 64-bit entry This allows comparing hash and len in one operation on 64-bit architectures. Right now only __d_lookup_rcu() takes advantage of this, since that is the case we care most about. The use of anonymous struct/unions hides the alternate 64-bit approach from most users, the exception being a few cases where we initialize a 'struct qstr' with a static initializer. This makes the problematic cases use a new QSTR_INIT() helper function for that (but initializing just the name pointer with a "{ .name = xyzzy }" initializer remains valid, as does just copying another qstr structure). Signed-off-by: Linus Torvalds --- fs/dcache.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'fs/dcache.c') diff --git a/fs/dcache.c b/fs/dcache.c index e6707a1f72c6..92099f61bc64 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1502,7 +1502,7 @@ struct dentry *d_make_root(struct inode *root_inode) struct dentry *res = NULL; if (root_inode) { - static const struct qstr name = { .name = "/", .len = 1 }; + static const struct qstr name = QSTR_INIT("/", 1); res = __d_alloc(root_inode->i_sb, &name); if (res) @@ -1816,10 +1816,9 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent, const struct qstr *name, unsigned *seqp, struct inode *inode) { - unsigned int len = name->len; - unsigned int hash = name->hash; + u64 hashlen = name->hash_len; const unsigned char *str = name->name; - struct hlist_bl_head *b = d_hash(parent, hash); + struct hlist_bl_head *b = d_hash(parent, hashlen_hash(hashlen)); struct hlist_bl_node *node; struct dentry *dentry; @@ -1846,9 +1845,6 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent, hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { unsigned seq; - if (dentry->d_name.hash != hash) - continue; - seqretry: /* * The dentry sequence count protects us from concurrent @@ -1871,6 +1867,8 @@ seqretry: *seqp = seq; if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { + if (dentry->d_name.hash != hashlen_hash(hashlen)) + continue; switch (slow_dentry_cmp(parent, inode, dentry, seq, name)) { case D_COMP_OK: return dentry; @@ -1881,9 +1879,9 @@ seqretry: } } - if (dentry->d_name.len != len) + if (dentry->d_name.hash_len != hashlen) continue; - if (!dentry_cmp(dentry, str, len)) + if (!dentry_cmp(dentry, str, hashlen_len(hashlen))) return dentry; } return NULL; -- cgit v1.2.3