1 files changed, 21 insertions, 65 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 0a38ef8d7f00..6055d61811d3 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -88,35 +88,6 @@ EXPORT_SYMBOL(rename_lock);
 
 static struct kmem_cache *dentry_cache __read_mostly;
 
-/**
- * read_seqbegin_or_lock - begin a sequence number check or locking block
- * @lock: sequence lock
- * @seq : sequence number to be checked
- *
- * First try it once optimistically without taking the lock. If that fails,
- * take the lock. The sequence number is also used as a marker for deciding
- * whether to be a reader (even) or writer (odd).
- * N.B. seq must be initialized to an even number to begin with.
- */
-static inline void read_seqbegin_or_lock(seqlock_t *lock, int *seq)
-{
-        if (!(*seq & 1))        /* Even */
-                *seq = read_seqbegin(lock);
-        else                    /* Odd */
-                read_seqlock_excl(lock);
-}
-
-static inline int need_seqretry(seqlock_t *lock, int seq)
-{
-        return !(seq & 1) && read_seqretry(lock, seq);
-}
-
-static inline void done_seqretry(seqlock_t *lock, int seq)
-{
-        if (seq & 1)
-                read_sequnlock_excl(lock);
-}
-
 /*
  * This is the single most critical data structure when it comes
  * to the dcache: the hashtable for lookups. Somebody should try
@@ -125,8 +96,6 @@ static inline void done_seqretry(seqlock_t *lock, int seq)
  * This hash-function tries to avoid losing too many bits of hash
  * information, yet avoid using a prime hash-size or similar.
  */
-#define D_HASHBITS     d_hash_shift
-#define D_HASHMASK     d_hash_mask
 
 static unsigned int d_hash_mask __read_mostly;
 static unsigned int d_hash_shift __read_mostly;
@@ -137,8 +106,8 @@ static inline struct hlist_bl_head *d_hash(const struct dentry *parent,
                                         unsigned int hash)
 {
         hash += (unsigned long) parent / L1_CACHE_BYTES;
-        hash = hash + (hash >> D_HASHBITS);
-        return dentry_hashtable + (hash & D_HASHMASK);
+        hash = hash + (hash >> d_hash_shift);
+        return dentry_hashtable + (hash & d_hash_mask);
 }
 
 /* Statistics gathering. */
@@ -223,7 +192,7 @@ static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char
                 if (!tcount)
                         return 0;
         }
-        mask = ~(~0ul << tcount*8);
+        mask = bytemask_from_count(tcount);
         return unlikely(!!((a ^ b) & mask));
 }
 
@@ -469,7 +438,7 @@ static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent)
 {
         list_del(&dentry->d_u.d_child);
         /*
-         * Inform try_to_ascend() that we are no longer attached to the
+         * Inform d_walk() that we are no longer attached to the
          * dentry tree
          */
         dentry->d_flags |= DCACHE_DENTRY_KILLED;
@@ -1069,34 +1038,6 @@ void shrink_dcache_sb(struct super_block *sb)
 }
 EXPORT_SYMBOL(shrink_dcache_sb);
 
-/*
- * This tries to ascend one level of parenthood, but
- * we can race with renaming, so we need to re-check
- * the parenthood after dropping the lock and check
- * that the sequence number still matches.
- */
-static struct dentry *try_to_ascend(struct dentry *old, unsigned seq)
-{
-        struct dentry *new = old->d_parent;
-
-        rcu_read_lock();
-        spin_unlock(&old->d_lock);
-        spin_lock(&new->d_lock);
-
-        /*
-         * might go back up the wrong parent if we have had a rename
-         * or deletion
-         */
-        if (new != old->d_parent ||
-                 (old->d_flags & DCACHE_DENTRY_KILLED) ||
-                 need_seqretry(&rename_lock, seq)) {
-                spin_unlock(&new->d_lock);
-                new = NULL;
-        }
-        rcu_read_unlock();
-        return new;
-}
-
 /**
  * enum d_walk_ret - action to talke during tree walk
  * @D_WALK_CONTINUE:    contrinue walk
@@ -1185,9 +1126,24 @@ resume:
          */
         if (this_parent != parent) {
                 struct dentry *child = this_parent;
-                this_parent = try_to_ascend(this_parent, seq);
-                if (!this_parent)
+                this_parent = child->d_parent;
+
+                rcu_read_lock();
+                spin_unlock(&child->d_lock);
+                spin_lock(&this_parent->d_lock);
+
+                /*
+                 * might go back up the wrong parent if we have had a rename
+                 * or deletion
+                 */
+                if (this_parent != child->d_parent ||
+                         (child->d_flags & DCACHE_DENTRY_KILLED) ||
+                         need_seqretry(&rename_lock, seq)) {
+                        spin_unlock(&this_parent->d_lock);
+                        rcu_read_unlock();
                         goto rename_retry;
+                }
+                rcu_read_unlock();
                 next = child->d_u.d_child.next;
                 goto resume;
         }