Revert to Fedora kernel-2.6.17-1.2187_FC5 patched with vs2.0.2.1; there are too many...
[linux-2.6.git] / fs / dcache.c
index 1ab2caf..5e279e6 100644 (file)
  */
 
 #include <linux/config.h>
+#include <linux/syscalls.h>
 #include <linux/string.h>
 #include <linux/mm.h>
 #include <linux/fs.h>
+#include <linux/fsnotify.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/smp_lock.h>
 #include <linux/swap.h>
 #include <linux/bootmem.h>
 
-/* #define DCACHE_DEBUG 1 */
 
-int sysctl_vfs_cache_pressure = 100;
+int sysctl_vfs_cache_pressure __read_mostly = 100;
+EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
 
-spinlock_t dcache_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
-seqlock_t rename_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED;
+ __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lock);
+static seqlock_t rename_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED;
 
 EXPORT_SYMBOL(dcache_lock);
 
-static kmem_cache_t *dentry_cache
+static kmem_cache_t *dentry_cache __read_mostly;
 
 #define DNAME_INLINE_LEN (sizeof(struct dentry)-offsetof(struct dentry,d_iname))
 
@@ -56,14 +58,11 @@ static kmem_cache_t *dentry_cache;
 #define D_HASHBITS     d_hash_shift
 #define D_HASHMASK     d_hash_mask
 
-static unsigned int d_hash_mask;
-static unsigned int d_hash_shift;
-static struct hlist_head *dentry_hashtable;
+static unsigned int d_hash_mask __read_mostly;
+static unsigned int d_hash_shift __read_mostly;
+static struct hlist_head *dentry_hashtable __read_mostly;
 static LIST_HEAD(dentry_unused);
 
-static void prune_dcache(int count);
-
-
 /* Statistics gathering. */
 struct dentry_stat_t dentry_stat = {
        .age_limit = 45,
@@ -71,7 +70,7 @@ struct dentry_stat_t dentry_stat = {
 
 static void d_callback(struct rcu_head *head)
 {
-       struct dentry * dentry = container_of(head, struct dentry, d_rcu);
+       struct dentry * dentry = container_of(head, struct dentry, d_u.d_rcu);
 
        if (dname_external(dentry))
                kfree(dentry->d_name.name);
@@ -86,7 +85,11 @@ static void d_free(struct dentry *dentry)
 {
        if (dentry->d_op && dentry->d_op->d_release)
                dentry->d_op->d_release(dentry);
-       call_rcu(&dentry->d_rcu, d_callback);
+       if (dentry->d_extra_attributes) {
+               kfree(dentry->d_extra_attributes);
+               dentry->d_extra_attributes = NULL;
+       }
+       call_rcu(&dentry->d_u.d_rcu, d_callback);
 }
 
 /*
@@ -94,7 +97,7 @@ static void d_free(struct dentry *dentry)
  * d_iput() operation if defined.
  * Called with dcache_lock and per dentry lock held, drops both.
  */
-static inline void dentry_iput(struct dentry * dentry)
+static void dentry_iput(struct dentry * dentry)
 {
        struct inode *inode = dentry->d_inode;
        if (inode) {
@@ -102,6 +105,8 @@ static inline void dentry_iput(struct dentry * dentry)
                list_del_init(&dentry->d_alias);
                spin_unlock(&dentry->d_lock);
                spin_unlock(&dcache_lock);
+               if (!inode->i_nlink)
+                       fsnotify_inoderemove(inode);
                if (dentry->d_op && dentry->d_op->d_iput)
                        dentry->d_op->d_iput(dentry, inode);
                else
@@ -147,6 +152,8 @@ void dput(struct dentry *dentry)
                return;
 
 repeat:
+       if (atomic_read(&dentry->d_count) == 1)
+               might_sleep();
        if (!atomic_dec_and_lock(&dentry->d_count, &dcache_lock))
                return;
 
@@ -156,7 +163,7 @@ repeat:
                spin_unlock(&dcache_lock);
                return;
        }
-                       
+
        /*
         * AV: ->d_delete() is _NOT_ allowed to block now.
         */
@@ -189,7 +196,7 @@ kill_it: {
                        list_del(&dentry->d_lru);
                        dentry_stat.nr_unused--;
                }
-               list_del(&dentry->d_child);
+               list_del(&dentry->d_u.d_child);
                dentry_stat.nr_dentry--;        /* For d_free, below */
                /*drops the locks, at that point nobody can reach this dentry */
                dentry_iput(dentry);
@@ -279,22 +286,25 @@ struct dentry * dget_locked(struct dentry *dentry)
 /**
  * d_find_alias - grab a hashed alias of inode
  * @inode: inode in question
+ * @want_discon:  flag, used by d_splice_alias, to request
+ *          that only a DISCONNECTED alias be returned.
  *
- * If inode has a hashed alias - acquire the reference to alias and
- * return it. Otherwise return NULL. Notice that if inode is a directory
- * there can be only one alias and it can be unhashed only if it has
- * no children.
+ * If inode has a hashed alias, or is a directory and has any alias,
+ * acquire the reference to alias and return it. Otherwise return NULL.
+ * Notice that if inode is a directory there can be only one alias and
+ * it can be unhashed only if it has no children, or if it is the root
+ * of a filesystem.
  *
  * If the inode has a DCACHE_DISCONNECTED alias, then prefer
- * any other hashed alias over that one.
+ * any other hashed alias over that one unless @want_discon is set,
+ * in which case only return a DCACHE_DISCONNECTED alias.
  */
 
-struct dentry * d_find_alias(struct inode *inode)
+static struct dentry * __d_find_alias(struct inode *inode, int want_discon)
 {
        struct list_head *head, *next, *tmp;
        struct dentry *alias, *discon_alias=NULL;
 
-       spin_lock(&dcache_lock);
        head = &inode->i_dentry;
        next = inode->i_dentry.next;
        while (next != head) {
@@ -302,41 +312,52 @@ struct dentry * d_find_alias(struct inode *inode)
                next = tmp->next;
                prefetch(next);
                alias = list_entry(tmp, struct dentry, d_alias);
-               if (!d_unhashed(alias)) {
+               if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
                        if (alias->d_flags & DCACHE_DISCONNECTED)
                                discon_alias = alias;
-                       else {
+                       else if (!want_discon) {
                                __dget_locked(alias);
-                               spin_unlock(&dcache_lock);
                                return alias;
                        }
                }
        }
        if (discon_alias)
                __dget_locked(discon_alias);
-       spin_unlock(&dcache_lock);
        return discon_alias;
 }
 
+struct dentry * d_find_alias(struct inode *inode)
+{
+       struct dentry *de = NULL;
+
+       if (!list_empty(&inode->i_dentry)) {
+               spin_lock(&dcache_lock);
+               de = __d_find_alias(inode, 0);
+               spin_unlock(&dcache_lock);
+       }
+       return de;
+}
+
 /*
  *     Try to kill dentries associated with this inode.
  * WARNING: you must own a reference to inode.
  */
 void d_prune_aliases(struct inode *inode)
 {
-       struct list_head *tmp, *head = &inode->i_dentry;
+       struct dentry *dentry;
 restart:
        spin_lock(&dcache_lock);
-       tmp = head;
-       while ((tmp = tmp->next) != head) {
-               struct dentry *dentry = list_entry(tmp, struct dentry, d_alias);
+       list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
+               spin_lock(&dentry->d_lock);
                if (!atomic_read(&dentry->d_count)) {
                        __dget_locked(dentry);
                        __d_drop(dentry);
+                       spin_unlock(&dentry->d_lock);
                        spin_unlock(&dcache_lock);
                        dput(dentry);
                        goto restart;
                }
+               spin_unlock(&dentry->d_lock);
        }
        spin_unlock(&dcache_lock);
 }
@@ -352,7 +373,7 @@ static inline void prune_one_dentry(struct dentry * dentry)
        struct dentry * parent;
 
        __d_drop(dentry);
-       list_del(&dentry->d_child);
+       list_del(&dentry->d_u.d_child);
        dentry_stat.nr_dentry--;        /* For d_free, below */
        dentry_iput(dentry);
        parent = dentry->d_parent;
@@ -447,10 +468,7 @@ void shrink_dcache_sb(struct super_block * sb)
         * superblock to the most recent end of the unused list.
         */
        spin_lock(&dcache_lock);
-       next = dentry_unused.next;
-       while (next != &dentry_unused) {
-               tmp = next;
-               next = tmp->next;
+       list_for_each_safe(tmp, next, &dentry_unused) {
                dentry = list_entry(tmp, struct dentry, d_lru);
                if (dentry->d_sb != sb)
                        continue;
@@ -462,10 +480,7 @@ void shrink_dcache_sb(struct super_block * sb)
         * Pass two ... free the dentries for this superblock.
         */
 repeat:
-       next = dentry_unused.next;
-       while (next != &dentry_unused) {
-               tmp = next;
-               next = tmp->next;
+       list_for_each_safe(tmp, next, &dentry_unused) {
                dentry = list_entry(tmp, struct dentry, d_lru);
                if (dentry->d_sb != sb)
                        continue;
@@ -477,6 +492,7 @@ repeat:
                        continue;
                }
                prune_one_dentry(dentry);
+               cond_resched_lock(&dcache_lock);
                goto repeat;
        }
        spin_unlock(&dcache_lock);
@@ -509,7 +525,7 @@ repeat:
 resume:
        while (next != &this_parent->d_subdirs) {
                struct list_head *tmp = next;
-               struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
+               struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
                next = tmp->next;
                /* Have we found a mount point ? */
                if (d_mountpoint(dentry))
@@ -523,7 +539,7 @@ resume:
         * All done at this level ... ascend and resume the search.
         */
        if (this_parent != parent) {
-               next = this_parent->d_child.next; 
+               next = this_parent->d_u.d_child.next;
                this_parent = this_parent->d_parent;
                goto resume;
        }
@@ -540,6 +556,13 @@ positive:
  * list for prune_dcache(). We descend to the next level
  * whenever the d_subdirs list is non-empty and continue
  * searching.
+ *
+ * It returns zero iff there are no unused children,
+ * otherwise  it returns the number of children moved to
+ * the end of the unused list. This may not be the total
+ * number of unused children, because select_parent can
+ * drop the lock and return early due to latency
+ * constraints.
  */
 static int select_parent(struct dentry * parent)
 {
@@ -553,7 +576,7 @@ repeat:
 resume:
        while (next != &this_parent->d_subdirs) {
                struct list_head *tmp = next;
-               struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
+               struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
                next = tmp->next;
 
                if (!list_empty(&dentry->d_lru)) {
@@ -569,15 +592,20 @@ resume:
                        dentry_stat.nr_unused++;
                        found++;
                }
+
+               /*
+                * We can return to the caller if we have found some (this
+                * ensures forward progress). We'll be coming back to find
+                * the rest.
+                */
+               if (found && need_resched())
+                       goto out;
+
                /*
                 * Descend a level if the d_subdirs list is non-empty.
                 */
                if (!list_empty(&dentry->d_subdirs)) {
                        this_parent = dentry;
-#ifdef DCACHE_DEBUG
-printk(KERN_DEBUG "select_parent: descending to %s/%s, found=%d\n",
-dentry->d_parent->d_name.name, dentry->d_name.name, found);
-#endif
                        goto repeat;
                }
        }
@@ -585,14 +613,11 @@ dentry->d_parent->d_name.name, dentry->d_name.name, found);
         * All done at this level ... ascend and resume the search.
         */
        if (this_parent != parent) {
-               next = this_parent->d_child.next; 
+               next = this_parent->d_u.d_child.next;
                this_parent = this_parent->d_parent;
-#ifdef DCACHE_DEBUG
-printk(KERN_DEBUG "select_parent: ascending to %s/%s, found=%d\n",
-this_parent->d_parent->d_name.name, this_parent->d_name.name, found);
-#endif
                goto resume;
        }
+out:
        spin_unlock(&dcache_lock);
        return found;
 }
@@ -618,7 +643,7 @@ void shrink_dcache_parent(struct dentry * parent)
  *
  * Prune the dentries that are anonymous
  *
- * parsing d_hash list does not read_barrier_depends() as it
+ * parsing d_hash list does not hlist_for_each_entry_rcu() as it
  * done under dcache_lock.
  *
  */
@@ -633,7 +658,7 @@ void shrink_dcache_anon(struct hlist_head *head)
                        struct dentry *this = hlist_entry(lp, struct dentry, d_hash);
                        if (!list_empty(&this->d_lru)) {
                                dentry_stat.nr_unused--;
-                               list_del(&this->d_lru);
+                               list_del_init(&this->d_lru);
                        }
 
                        /* 
@@ -663,7 +688,7 @@ void shrink_dcache_anon(struct hlist_head *head)
  *
  * In this case we return -1 to tell the caller that we baled.
  */
-static int shrink_dcache_memory(int nr, unsigned int gfp_mask)
+static int shrink_dcache_memory(int nr, gfp_t gfp_mask)
 {
        if (nr) {
                if (!(gfp_mask & __GFP_FS))
@@ -688,19 +713,6 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
        struct dentry *dentry;
        char *dname;
 
-#define DENTRY_UNUSED_THRESHOLD 30000
-#define DENTRY_BATCH_COUNT 32
-       if (dentry_stat.nr_unused > DENTRY_UNUSED_THRESHOLD) {
-               int doit = 1;
-               spin_lock(&dcache_lock);
-               if (dentry_stat.nr_unused < DENTRY_UNUSED_THRESHOLD)
-                       doit = 0;
-               spin_unlock(&dcache_lock);
-               if (doit)
-                       prune_dcache(DENTRY_BATCH_COUNT);
-       }
-
        dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL); 
        if (!dentry)
                return NULL;
@@ -723,15 +735,17 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
 
        atomic_set(&dentry->d_count, 1);
        dentry->d_flags = DCACHE_UNHASHED;
-       dentry->d_lock = SPIN_LOCK_UNLOCKED;
+       spin_lock_init(&dentry->d_lock);
        dentry->d_inode = NULL;
        dentry->d_parent = NULL;
        dentry->d_sb = NULL;
        dentry->d_op = NULL;
        dentry->d_fsdata = NULL;
+       dentry->d_extra_attributes = NULL;
        dentry->d_mounted = 0;
+#ifdef CONFIG_PROFILING
        dentry->d_cookie = NULL;
-       dentry->d_bucket = NULL;
+#endif
        INIT_HLIST_NODE(&dentry->d_hash);
        INIT_LIST_HEAD(&dentry->d_lru);
        INIT_LIST_HEAD(&dentry->d_subdirs);
@@ -741,18 +755,28 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
                dentry->d_parent = dget(parent);
                dentry->d_sb = parent->d_sb;
        } else {
-               INIT_LIST_HEAD(&dentry->d_child);
+               INIT_LIST_HEAD(&dentry->d_u.d_child);
        }
 
        spin_lock(&dcache_lock);
        if (parent)
-               list_add(&dentry->d_child, &parent->d_subdirs);
+               list_add(&dentry->d_u.d_child, &parent->d_subdirs);
        dentry_stat.nr_dentry++;
        spin_unlock(&dcache_lock);
 
        return dentry;
 }
 
+struct dentry *d_alloc_name(struct dentry *parent, const char *name)
+{
+       struct qstr q;
+
+       q.name = name;
+       q.len = strlen(name);
+       q.hash = full_name_hash(q.name, q.len);
+       return d_alloc(parent, &q);
+}
+
 /**
  * d_instantiate - fill in inode information for a dentry
  * @entry: dentry to complete
@@ -770,14 +794,69 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
  
 void d_instantiate(struct dentry *entry, struct inode * inode)
 {
-       if (!list_empty(&entry->d_alias)) BUG();
+       BUG_ON(!list_empty(&entry->d_alias));
        spin_lock(&dcache_lock);
        if (inode)
                list_add(&entry->d_alias, &inode->i_dentry);
        entry->d_inode = inode;
+       fsnotify_d_instantiate(entry, inode);
+       spin_unlock(&dcache_lock);
+       security_d_instantiate(entry, inode);
+}
+
+/**
+ * d_instantiate_unique - instantiate a non-aliased dentry
+ * @entry: dentry to instantiate
+ * @inode: inode to attach to this dentry
+ *
+ * Fill in inode information in the entry. On success, it returns NULL.
+ * If an unhashed alias of "entry" already exists, then we return the
+ * aliased dentry instead and drop one reference to inode.
+ *
+ * Note that in order to avoid conflicts with rename() etc, the caller
+ * had better be holding the parent directory semaphore.
+ *
+ * This also assumes that the inode count has been incremented
+ * (or otherwise set) by the caller to indicate that it is now
+ * in use by the dcache.
+ */
+struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode)
+{
+       struct dentry *alias;
+       int len = entry->d_name.len;
+       const char *name = entry->d_name.name;
+       unsigned int hash = entry->d_name.hash;
+
+       BUG_ON(!list_empty(&entry->d_alias));
+       spin_lock(&dcache_lock);
+       if (!inode)
+               goto do_negative;
+       list_for_each_entry(alias, &inode->i_dentry, d_alias) {
+               struct qstr *qstr = &alias->d_name;
+
+               if (qstr->hash != hash)
+                       continue;
+               if (alias->d_parent != entry->d_parent)
+                       continue;
+               if (qstr->len != len)
+                       continue;
+               if (memcmp(qstr->name, name, len))
+                       continue;
+               dget_locked(alias);
+               spin_unlock(&dcache_lock);
+               BUG_ON(!d_unhashed(alias));
+               iput(inode);
+               return alias;
+       }
+       list_add(&entry->d_alias, &inode->i_dentry);
+do_negative:
+       entry->d_inode = inode;
+       fsnotify_d_instantiate(entry, inode);
        spin_unlock(&dcache_lock);
        security_d_instantiate(entry, inode);
+       return NULL;
 }
+EXPORT_SYMBOL(d_instantiate_unique);
 
 /**
  * d_alloc_root - allocate root dentry
@@ -851,33 +930,21 @@ struct dentry * d_alloc_anon(struct inode *inode)
        tmp->d_parent = tmp; /* make sure dput doesn't croak */
        
        spin_lock(&dcache_lock);
-       if (S_ISDIR(inode->i_mode) && !list_empty(&inode->i_dentry)) {
-               /* A directory can only have one dentry.
-                * This (now) has one, so use it.
-                */
-               res = list_entry(inode->i_dentry.next, struct dentry, d_alias);
-               __dget_locked(res);
-       } else {
+       res = __d_find_alias(inode, 0);
+       if (!res) {
                /* attach a disconnected dentry */
                res = tmp;
                tmp = NULL;
-               if (res) {
-                       spin_lock(&res->d_lock);
-                       res->d_sb = inode->i_sb;
-                       res->d_parent = res;
-                       res->d_inode = inode;
+               spin_lock(&res->d_lock);
+               res->d_sb = inode->i_sb;
+               res->d_parent = res;
+               res->d_inode = inode;
+               res->d_flags |= DCACHE_DISCONNECTED;
+               res->d_flags &= ~DCACHE_UNHASHED;
+               list_add(&res->d_alias, &inode->i_dentry);
+               hlist_add_head(&res->d_hash, &inode->i_sb->s_anon);
+               spin_unlock(&res->d_lock);
 
-                       /*
-                        * Set d_bucket to an "impossible" bucket address so
-                        * that d_move() doesn't get a false positive
-                        */
-                       res->d_bucket = NULL;
-                       res->d_flags |= DCACHE_DISCONNECTED;
-                       res->d_flags &= ~DCACHE_UNHASHED;
-                       list_add(&res->d_alias, &inode->i_dentry);
-                       hlist_add_head(&res->d_hash, &inode->i_sb->s_anon);
-                       spin_unlock(&res->d_lock);
-               }
                inode = NULL; /* don't drop reference */
        }
        spin_unlock(&dcache_lock);
@@ -899,7 +966,7 @@ struct dentry * d_alloc_anon(struct inode *inode)
  * DCACHE_DISCONNECTED), then d_move that in place of the given dentry
  * and return it, else simply d_add the inode to the dentry and return NULL.
  *
- * This is (will be) needed in the lookup routine of any filesystem that is exportable
+ * This is needed in the lookup routine of any filesystem that is exportable
  * (via knfsd) so that we can build dcache paths to directories effectively.
  *
  * If a dentry was found and moved, then it is returned.  Otherwise NULL
@@ -910,11 +977,12 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
 {
        struct dentry *new = NULL;
 
-       if (inode && S_ISDIR(inode->i_mode)) {
+       if (inode) {
                spin_lock(&dcache_lock);
-               if (!list_empty(&inode->i_dentry)) {
-                       new = list_entry(inode->i_dentry.next, struct dentry, d_alias);
-                       __dget_locked(new);
+               new = __d_find_alias(inode, 1);
+               if (new) {
+                       BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED));
+                       fsnotify_d_instantiate(new, inode);
                        spin_unlock(&dcache_lock);
                        security_d_instantiate(new, inode);
                        d_rehash(dentry);
@@ -924,6 +992,7 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
                        /* d_instantiate takes dcache_lock, so we do it by hand */
                        list_add(&dentry->d_alias, &inode->i_dentry);
                        dentry->d_inode = inode;
+                       fsnotify_d_instantiate(dentry, inode);
                        spin_unlock(&dcache_lock);
                        security_d_instantiate(dentry, inode);
                        d_rehash(dentry);
@@ -985,18 +1054,13 @@ struct dentry * __d_lookup(struct dentry * parent, struct qstr * name)
        struct hlist_head *head = d_hash(parent,hash);
        struct dentry *found = NULL;
        struct hlist_node *node;
+       struct dentry *dentry;
 
        rcu_read_lock();
        
-       hlist_for_each (node, head) { 
-               struct dentry *dentry; 
+       hlist_for_each_entry_rcu(dentry, node, head, d_hash) {
                struct qstr *qstr;
 
-               smp_read_barrier_depends();
-               dentry = hlist_entry(node, struct dentry, d_hash);
-
-               smp_rmb();
-
                if (dentry->d_name.hash != hash)
                        continue;
                if (dentry->d_parent != parent)
@@ -1004,13 +1068,6 @@ struct dentry * __d_lookup(struct dentry * parent, struct qstr * name)
 
                spin_lock(&dentry->d_lock);
 
-               /*
-                * If lookup ends up in a different bucket due to concurrent
-                * rename, fail it
-                */
-               if (unlikely(dentry->d_bucket != head))
-                       goto terminate;
-
                /*
                 * Recheck the dentry after taking the lock - d_move may have
                 * changed things.  Don't bother checking the hash because we're
@@ -1019,8 +1076,11 @@ struct dentry * __d_lookup(struct dentry * parent, struct qstr * name)
                if (dentry->d_parent != parent)
                        goto next;
 
+               /*
+                * It is safe to compare names since d_move() cannot
+                * change the qstr (protected by d_lock).
+                */
                qstr = &dentry->d_name;
-               smp_read_barrier_depends();
                if (parent->d_op && parent->d_op->d_compare) {
                        if (parent->d_op->d_compare(parent, qstr, name))
                                goto next;
@@ -1035,7 +1095,6 @@ struct dentry * __d_lookup(struct dentry * parent, struct qstr * name)
                        atomic_inc(&dentry->d_count);
                        found = dentry;
                }
-terminate:
                spin_unlock(&dentry->d_lock);
                break;
 next:
@@ -1046,6 +1105,32 @@ next:
        return found;
 }
 
+/**
+ * d_hash_and_lookup - hash the qstr then search for a dentry
+ * @dir: Directory to search in
+ * @name: qstr of name we wish to find
+ *
+ * On hash failure or on lookup failure NULL is returned.
+ */
+struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
+{
+       struct dentry *dentry = NULL;
+
+       /*
+        * Check for a fs-specific hash function. Note that we must
+        * calculate the standard hash first, as the d_op->d_hash()
+        * routine may choose to leave the hash value unchanged.
+        */
+       name->hash = full_name_hash(name->name, name->len);
+       if (dir->d_op && dir->d_op->d_hash) {
+               if (dir->d_op->d_hash(dir, name) < 0)
+                       goto out;
+       }
+       dentry = d_lookup(dir, name);
+out:
+       return dentry;
+}
+
 /**
  * d_validate - verify dentry provided from insecure source
  * @dentry: The dentry alleged to be valid child of @dparent
@@ -1073,7 +1158,7 @@ int d_validate(struct dentry *dentry, struct dentry *dparent)
        spin_lock(&dcache_lock);
        base = d_hash(dparent, dentry->d_name.hash);
        hlist_for_each(lhp,base) { 
-               /* read_barrier_depends() not required for d_hash list
+               /* hlist_for_each_entry_rcu() not required for d_hash list
                 * as it is parsed under dcache_lock
                 */
                if (dentry == hlist_entry(lhp, struct dentry, d_hash)) {
@@ -1110,13 +1195,19 @@ out:
  
 void d_delete(struct dentry * dentry)
 {
+       int isdir = 0;
        /*
         * Are we the only user?
         */
        spin_lock(&dcache_lock);
        spin_lock(&dentry->d_lock);
+       isdir = S_ISDIR(dentry->d_inode->i_mode);
        if (atomic_read(&dentry->d_count) == 1) {
                dentry_iput(dentry);
+               fsnotify_nameremove(dentry, isdir);
+
+               /* remove this and other inotify debug checks after 2.6.18 */
+               dentry->d_flags &= ~DCACHE_INOTIFY_PARENT_WATCHED;
                return;
        }
 
@@ -1125,6 +1216,15 @@ void d_delete(struct dentry * dentry)
 
        spin_unlock(&dentry->d_lock);
        spin_unlock(&dcache_lock);
+
+       fsnotify_nameremove(dentry, isdir);
+}
+
+static void __d_rehash(struct dentry * entry, struct hlist_head *list)
+{
+
+       entry->d_flags &= ~DCACHE_UNHASHED;
+       hlist_add_head_rcu(&entry->d_hash, list);
 }
 
 /**
@@ -1140,10 +1240,8 @@ void d_rehash(struct dentry * entry)
 
        spin_lock(&dcache_lock);
        spin_lock(&entry->d_lock);
-       entry->d_flags &= ~DCACHE_UNHASHED;
+       __d_rehash(entry, list);
        spin_unlock(&entry->d_lock);
-       entry->d_bucket = list;
-       hlist_add_head_rcu(&entry->d_hash, list);
        spin_unlock(&dcache_lock);
 }
 
@@ -1221,6 +1319,8 @@ static void switch_names(struct dentry *dentry, struct dentry *target)
 
 void d_move(struct dentry * dentry, struct dentry * target)
 {
+       struct hlist_head *list;
+
        if (!dentry->d_inode)
                printk(KERN_WARNING "VFS: moving negative dcache entry\n");
 
@@ -1240,23 +1340,31 @@ void d_move(struct dentry * dentry, struct dentry * target)
        /* Move the dentry to the target hash queue, if on different bucket */
        if (dentry->d_flags & DCACHE_UNHASHED)
                goto already_unhashed;
-       if (dentry->d_bucket != target->d_bucket) {
-               hlist_del_rcu(&dentry->d_hash);
+
+       hlist_del_rcu(&dentry->d_hash);
+
 already_unhashed:
-               dentry->d_bucket = target->d_bucket;
-               hlist_add_head_rcu(&dentry->d_hash, target->d_bucket);
-               dentry->d_flags &= ~DCACHE_UNHASHED;
-       }
+       list = d_hash(target->d_parent, target->d_name.hash);
+       __d_rehash(dentry, list);
 
        /* Unhash the target: dput() will then get rid of it */
        __d_drop(target);
 
-       list_del(&dentry->d_child);
-       list_del(&target->d_child);
+       /* flush any possible attributes */
+       if (dentry->d_extra_attributes) {
+               kfree(dentry->d_extra_attributes);
+               dentry->d_extra_attributes = NULL;
+       }
+       if (target->d_extra_attributes) {
+               kfree(target->d_extra_attributes);
+               target->d_extra_attributes = NULL;
+       }
+       list_del(&dentry->d_u.d_child);
+       list_del(&target->d_u.d_child);
 
        /* Switch the names.. */
        switch_names(dentry, target);
-       smp_wmb();
        do_switch(dentry->d_name.len, target->d_name.len);
        do_switch(dentry->d_name.hash, target->d_name.hash);
 
@@ -1264,16 +1372,17 @@ already_unhashed:
        if (IS_ROOT(dentry)) {
                dentry->d_parent = target->d_parent;
                target->d_parent = target;
-               INIT_LIST_HEAD(&target->d_child);
+               INIT_LIST_HEAD(&target->d_u.d_child);
        } else {
                do_switch(dentry->d_parent, target->d_parent);
 
                /* And add them back to the (new) parent lists */
-               list_add(&target->d_child, &target->d_parent->d_subdirs);
+               list_add(&target->d_u.d_child, &target->d_parent->d_subdirs);
        }
 
-       list_add(&dentry->d_child, &dentry->d_parent->d_subdirs);
+       list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
        spin_unlock(&target->d_lock);
+       fsnotify_d_move(dentry);
        spin_unlock(&dentry->d_lock);
        write_sequnlock(&rename_lock);
        spin_unlock(&dcache_lock);
@@ -1295,7 +1404,7 @@ already_unhashed:
  *
  * "buflen" should be positive. Caller holds the dcache_lock.
  */
-static char * __d_path( struct dentry *dentry, struct vfsmount *vfsmnt,
+char * __d_path( struct dentry *dentry, struct vfsmount *vfsmnt,
                        struct dentry *root, struct vfsmount *rootmnt,
                        char *buffer, int buflen)
 {
@@ -1363,6 +1472,8 @@ Elong:
        return ERR_PTR(-ENAMETOOLONG);
 }
 
+EXPORT_SYMBOL_GPL(__d_path);
+
 /* write full pathname into buffer and return start of pathname */
 char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
                                char *buf, int buflen)
@@ -1473,7 +1584,6 @@ int is_subdir(struct dentry * new_dentry, struct dentry * old_dentry)
        struct dentry * saved = new_dentry;
        unsigned long seq;
 
-       result = 0;
        /* need rcu_readlock to protect against the d_parent trashing due to
         * d_move
         */
@@ -1481,6 +1591,7 @@ int is_subdir(struct dentry * new_dentry, struct dentry * old_dentry)
         do {
                /* for restarting inner loop in case of seq retry */
                new_dentry = saved;
+               result = 0;
                seq = read_seqbegin(&rename_lock);
                for (;;) {
                        if (new_dentry != old_dentry) {
@@ -1510,7 +1621,7 @@ repeat:
 resume:
        while (next != &this_parent->d_subdirs) {
                struct list_head *tmp = next;
-               struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
+               struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
                next = tmp->next;
                if (d_unhashed(dentry)||!dentry->d_inode)
                        continue;
@@ -1521,7 +1632,7 @@ resume:
                atomic_dec(&dentry->d_count);
        }
        if (this_parent != root) {
-               next = this_parent->d_child.next; 
+               next = this_parent->d_u.d_child.next;
                atomic_dec(&this_parent->d_count);
                this_parent = this_parent->d_parent;
                goto resume;
@@ -1548,26 +1659,12 @@ ino_t find_inode_number(struct dentry *dir, struct qstr *name)
        struct dentry * dentry;
        ino_t ino = 0;
 
-       /*
-        * Check for a fs-specific hash function. Note that we must
-        * calculate the standard hash first, as the d_op->d_hash()
-        * routine may choose to leave the hash value unchanged.
-        */
-       name->hash = full_name_hash(name->name, name->len);
-       if (dir->d_op && dir->d_op->d_hash)
-       {
-               if (dir->d_op->d_hash(dir, name) != 0)
-                       goto out;
-       }
-
-       dentry = d_lookup(dir, name);
-       if (dentry)
-       {
+       dentry = d_hash_and_lookup(dir, name);
+       if (dentry) {
                if (dentry->d_inode)
                        ino = dentry->d_inode->i_ino;
                dput(dentry);
        }
-out:
        return ino;
 }
 
@@ -1585,21 +1682,47 @@ static void __init dcache_init_early(void)
 {
        int loop;
 
+       /* If hashes are distributed across NUMA nodes, defer
+        * hash allocation until vmalloc space is available.
+        */
+       if (hashdist)
+               return;
+
        dentry_hashtable =
                alloc_large_system_hash("Dentry cache",
                                        sizeof(struct hlist_head),
                                        dhash_entries,
                                        13,
-                                       0,
+                                       HASH_EARLY,
                                        &d_hash_shift,
-                                       &d_hash_mask);
+                                       &d_hash_mask,
+                                       0);
 
        for (loop = 0; loop < (1 << d_hash_shift); loop++)
                INIT_HLIST_HEAD(&dentry_hashtable[loop]);
 }
 
+void flush_dentry_attributes (void)
+{
+       struct hlist_node *tmp;
+       struct dentry *dentry;
+       int i;
+
+       spin_lock(&dcache_lock);
+       for (i = 0; i <= d_hash_mask; i++)
+               hlist_for_each_entry(dentry, tmp, dentry_hashtable+i, d_hash) {
+                       kfree(dentry->d_extra_attributes);
+                       dentry->d_extra_attributes = NULL;
+               }
+       spin_unlock(&dcache_lock);
+}
+
+EXPORT_SYMBOL_GPL(flush_dentry_attributes);
+
 static void __init dcache_init(unsigned long mempages)
 {
+       int loop;
+
        /* 
         * A constructor could be added for stable state like the lists,
         * but it is probably not worth it because of the cache nature
@@ -1608,17 +1731,35 @@ static void __init dcache_init(unsigned long mempages)
        dentry_cache = kmem_cache_create("dentry_cache",
                                         sizeof(struct dentry),
                                         0,
-                                        SLAB_RECLAIM_ACCOUNT|SLAB_PANIC,
+                                        (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
+                                        SLAB_MEM_SPREAD),
                                         NULL, NULL);
        
        set_shrinker(DEFAULT_SEEKS, shrink_dcache_memory);
+
+       /* Hash may have been set up in dcache_init_early */
+       if (!hashdist)
+               return;
+
+       dentry_hashtable =
+               alloc_large_system_hash("Dentry cache",
+                                       sizeof(struct hlist_head),
+                                       dhash_entries,
+                                       13,
+                                       0,
+                                       &d_hash_shift,
+                                       &d_hash_mask,
+                                       0);
+
+       for (loop = 0; loop < (1 << d_hash_shift); loop++)
+               INIT_HLIST_HEAD(&dentry_hashtable[loop]);
 }
 
 /* SLAB cache for __getname() consumers */
-kmem_cache_t *names_cachep;
+kmem_cache_t *names_cachep __read_mostly;
 
 /* SLAB cache for file structures */
-kmem_cache_t *filp_cachep;
+kmem_cache_t *filp_cachep __read_mostly;
 
 EXPORT_SYMBOL(d_genocide);
 
@@ -1645,7 +1786,7 @@ void __init vfs_caches_init(unsigned long mempages)
                        SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
 
        filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,
-                       SLAB_HWCACHE_ALIGN|SLAB_PANIC, filp_ctor, filp_dtor);
+                       SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
 
        dcache_init(mempages);
        inode_init(mempages);
@@ -1673,8 +1814,6 @@ EXPORT_SYMBOL(dget_locked);
 EXPORT_SYMBOL(dput);
 EXPORT_SYMBOL(find_inode_number);
 EXPORT_SYMBOL(have_submounts);
-EXPORT_SYMBOL(is_subdir);
 EXPORT_SYMBOL(names_cachep);
-EXPORT_SYMBOL(shrink_dcache_anon);
 EXPORT_SYMBOL(shrink_dcache_parent);
 EXPORT_SYMBOL(shrink_dcache_sb);