diff options
| -rw-r--r-- | fs/dcache.c | 72 |
1 files changed, 49 insertions, 23 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index c5dc32a59c76..bb0c4d0038db 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2270,6 +2270,48 @@ bool d_same_name(const struct dentry *dentry, const struct dentry *parent, } EXPORT_SYMBOL_GPL(d_same_name); +/* + * This is __d_lookup_rcu() when the parent dentry has + * DCACHE_OP_COMPARE, which makes things much nastier. + */ +static noinline struct dentry *__d_lookup_rcu_op_compare( + const struct dentry *parent, + const struct qstr *name, + unsigned *seqp) +{ + u64 hashlen = name->hash_len; + struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen)); + struct hlist_bl_node *node; + struct dentry *dentry; + + hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { + int tlen; + const char *tname; + unsigned seq; + +seqretry: + seq = raw_seqcount_begin(&dentry->d_seq); + if (dentry->d_parent != parent) + continue; + if (d_unhashed(dentry)) + continue; + if (dentry->d_name.hash != hashlen_hash(hashlen)) + continue; + tlen = dentry->d_name.len; + tname = dentry->d_name.name; + /* we want a consistent (name,len) pair */ + if (read_seqcount_retry(&dentry->d_seq, seq)) { + cpu_relax(); + goto seqretry; + } + if (parent->d_op->d_compare(dentry, tlen, tname, name) != 0) + continue; + *seqp = seq; + return dentry; + } + return NULL; +} + /** * __d_lookup_rcu - search for a dentry (racy, store-free) * @parent: parent dentry @@ -2316,6 +2358,9 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent, * Keep the two functions in sync. */ + if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) + return __d_lookup_rcu_op_compare(parent, name, seqp); + /* * The hash list is protected using RCU. * @@ -2332,7 +2377,6 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent, hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { unsigned seq; -seqretry: /* * The dentry sequence count protects us from concurrent * renames, and thus protects parent and name fields. @@ -2355,28 +2399,10 @@ seqretry: continue; if (d_unhashed(dentry)) continue; - - if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { - int tlen; - const char *tname; - if (dentry->d_name.hash != hashlen_hash(hashlen)) - continue; - tlen = dentry->d_name.len; - tname = dentry->d_name.name; - /* we want a consistent (name,len) pair */ - if (read_seqcount_retry(&dentry->d_seq, seq)) { - cpu_relax(); - goto seqretry; - } - if (parent->d_op->d_compare(dentry, - tlen, tname, name) != 0) - continue; - } else { - if (dentry->d_name.hash_len != hashlen) - continue; - if (dentry_cmp(dentry, str, hashlen_len(hashlen)) != 0) - continue; - } + if (dentry->d_name.hash_len != hashlen) + continue; + if (dentry_cmp(dentry, str, hashlen_len(hashlen)) != 0) + continue; *seqp = seq; return dentry; } |