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authorLinus Torvalds <torvalds@linux-foundation.org>2012-05-10 13:14:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-10 19:54:35 -0700
commit26fe575028703948880fce4355a210c76bb0536e (patch)
tree0a7d04289e1eb1f1739659ebc9498d40f2add5da /fs/dcache.c
parentee983e89670704b2a05e897b161f2674a42d1508 (diff)
downloadvexpress-lsk-26fe575028703948880fce4355a210c76bb0536e.tar.gz
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 <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/dcache.c')
-rw-r--r--fs/dcache.c16
1 files changed, 7 insertions, 9 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index e6707a1f72c..92099f61bc6 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;