}
/*
- * dentry_lru_(add|add_tail|del|del_init) must be called with dcache_lock held.
+ * dentry_lru_(add|del|move_tail) must be called with dcache_lock held.
*/
static void dentry_lru_add(struct dentry *dentry)
{
- list_add(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
- dentry->d_sb->s_nr_dentry_unused++;
- percpu_counter_inc(&nr_dentry_unused);
-}
-
-static void dentry_lru_add_tail(struct dentry *dentry)
-{
- list_add_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
- dentry->d_sb->s_nr_dentry_unused++;
- percpu_counter_inc(&nr_dentry_unused);
+ if (list_empty(&dentry->d_lru)) {
+ list_add(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
+ dentry->d_sb->s_nr_dentry_unused++;
+ percpu_counter_inc(&nr_dentry_unused);
+ }
}
static void dentry_lru_del(struct dentry *dentry)
{
if (!list_empty(&dentry->d_lru)) {
- list_del(&dentry->d_lru);
+ list_del_init(&dentry->d_lru);
dentry->d_sb->s_nr_dentry_unused--;
percpu_counter_dec(&nr_dentry_unused);
}
}
-static void dentry_lru_del_init(struct dentry *dentry)
+static void dentry_lru_move_tail(struct dentry *dentry)
{
- if (likely(!list_empty(&dentry->d_lru))) {
- list_del_init(&dentry->d_lru);
- dentry->d_sb->s_nr_dentry_unused--;
- percpu_counter_dec(&nr_dentry_unused);
+ if (list_empty(&dentry->d_lru)) {
+ list_add_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
+ dentry->d_sb->s_nr_dentry_unused++;
+ percpu_counter_inc(&nr_dentry_unused);
+ } else {
+ list_move_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
}
}
if (dentry->d_op->d_delete(dentry))
goto unhash_it;
}
+
/* Unreachable? Get rid of it */
if (d_unhashed(dentry))
goto kill_it;
- if (list_empty(&dentry->d_lru)) {
- dentry->d_flags |= DCACHE_REFERENCED;
- dentry_lru_add(dentry);
- }
+
+ /* Otherwise leave it cached and ensure it's on the LRU */
+ dentry->d_flags |= DCACHE_REFERENCED;
+ dentry_lru_add(dentry);
+
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
return;
static inline struct dentry * __dget_locked(struct dentry *dentry)
{
atomic_inc(&dentry->d_count);
- dentry_lru_del_init(dentry);
+ dentry_lru_del(dentry);
return dentry;
}
if (dentry->d_op && dentry->d_op->d_delete)
dentry->d_op->d_delete(dentry);
- dentry_lru_del_init(dentry);
+ dentry_lru_del(dentry);
__d_drop(dentry);
dentry = d_kill(dentry);
spin_lock(&dcache_lock);
}
}
-/*
- * Shrink the dentry LRU on a given superblock.
- * @sb : superblock to shrink dentry LRU.
- * @count: If count is NULL, we prune all dentries on superblock.
- * @flags: If flags is non-zero, we need to do special processing based on
- * which flags are set. This means we don't need to maintain multiple
- * similar copies of this loop.
- */
-static void __shrink_dcache_sb(struct super_block *sb, int *count, int flags)
+static void shrink_dentry_list(struct list_head *list)
{
- LIST_HEAD(referenced);
- LIST_HEAD(tmp);
struct dentry *dentry;
- int cnt = 0;
- BUG_ON(!sb);
- BUG_ON((flags & DCACHE_REFERENCED) && count == NULL);
- spin_lock(&dcache_lock);
- if (count != NULL)
- /* called from prune_dcache() and shrink_dcache_parent() */
- cnt = *count;
-restart:
- if (count == NULL)
- list_splice_init(&sb->s_dentry_lru, &tmp);
- else {
- while (!list_empty(&sb->s_dentry_lru)) {
- dentry = list_entry(sb->s_dentry_lru.prev,
- struct dentry, d_lru);
- BUG_ON(dentry->d_sb != sb);
+ while (!list_empty(list)) {
+ dentry = list_entry(list->prev, struct dentry, d_lru);
+ dentry_lru_del(dentry);
- spin_lock(&dentry->d_lock);
- /*
- * If we are honouring the DCACHE_REFERENCED flag and
- * the dentry has this flag set, don't free it. Clear
- * the flag and put it back on the LRU.
- */
- if ((flags & DCACHE_REFERENCED)
- && (dentry->d_flags & DCACHE_REFERENCED)) {
- dentry->d_flags &= ~DCACHE_REFERENCED;
- list_move(&dentry->d_lru, &referenced);
- spin_unlock(&dentry->d_lock);
- } else {
- list_move_tail(&dentry->d_lru, &tmp);
- spin_unlock(&dentry->d_lock);
- cnt--;
- if (!cnt)
- break;
- }
- cond_resched_lock(&dcache_lock);
- }
- }
- while (!list_empty(&tmp)) {
- dentry = list_entry(tmp.prev, struct dentry, d_lru);
- dentry_lru_del_init(dentry);
- spin_lock(&dentry->d_lock);
/*
* We found an inuse dentry which was not removed from
* the LRU because of laziness during lookup. Do not free
* it - just keep it off the LRU list.
*/
+ spin_lock(&dentry->d_lock);
if (atomic_read(&dentry->d_count)) {
spin_unlock(&dentry->d_lock);
continue;
/* dentry->d_lock was dropped in prune_one_dentry() */
cond_resched_lock(&dcache_lock);
}
- if (count == NULL && !list_empty(&sb->s_dentry_lru))
- goto restart;
- if (count != NULL)
- *count = cnt;
+}
+
+/**
+ * __shrink_dcache_sb - shrink the dentry LRU on a given superblock
+ * @sb: superblock to shrink dentry LRU.
+ * @count: number of entries to prune
+ * @flags: flags to control the dentry processing
+ *
+ * If flags contains DCACHE_REFERENCED reference dentries will not be pruned.
+ */
+static void __shrink_dcache_sb(struct super_block *sb, int *count, int flags)
+{
+ /* called from prune_dcache() and shrink_dcache_parent() */
+ struct dentry *dentry;
+ LIST_HEAD(referenced);
+ LIST_HEAD(tmp);
+ int cnt = *count;
+
+ spin_lock(&dcache_lock);
+ while (!list_empty(&sb->s_dentry_lru)) {
+ dentry = list_entry(sb->s_dentry_lru.prev,
+ struct dentry, d_lru);
+ BUG_ON(dentry->d_sb != sb);
+
+ /*
+ * If we are honouring the DCACHE_REFERENCED flag and the
+ * dentry has this flag set, don't free it. Clear the flag
+ * and put it back on the LRU.
+ */
+ if (flags & DCACHE_REFERENCED) {
+ spin_lock(&dentry->d_lock);
+ if (dentry->d_flags & DCACHE_REFERENCED) {
+ dentry->d_flags &= ~DCACHE_REFERENCED;
+ list_move(&dentry->d_lru, &referenced);
+ spin_unlock(&dentry->d_lock);
+ cond_resched_lock(&dcache_lock);
+ continue;
+ }
+ spin_unlock(&dentry->d_lock);
+ }
+
+ list_move_tail(&dentry->d_lru, &tmp);
+ if (!--cnt)
+ break;
+ cond_resched_lock(&dcache_lock);
+ }
+
+ *count = cnt;
+ shrink_dentry_list(&tmp);
+
if (!list_empty(&referenced))
list_splice(&referenced, &sb->s_dentry_lru);
spin_unlock(&dcache_lock);
+
}
/**
* shrink_dcache_sb - shrink dcache for a superblock
* @sb: superblock
*
- * Shrink the dcache for the specified super block. This
- * is used to free the dcache before unmounting a file
- * system
+ * Shrink the dcache for the specified super block. This is used to free
+ * the dcache before unmounting a file system.
*/
-void shrink_dcache_sb(struct super_block * sb)
+void shrink_dcache_sb(struct super_block *sb)
{
- __shrink_dcache_sb(sb, NULL, 0);
+ LIST_HEAD(tmp);
+
+ spin_lock(&dcache_lock);
+ while (!list_empty(&sb->s_dentry_lru)) {
+ list_splice_init(&sb->s_dentry_lru, &tmp);
+ shrink_dentry_list(&tmp);
+ }
+ spin_unlock(&dcache_lock);
}
EXPORT_SYMBOL(shrink_dcache_sb);
/* detach this root from the system */
spin_lock(&dcache_lock);
- dentry_lru_del_init(dentry);
+ dentry_lru_del(dentry);
__d_drop(dentry);
spin_unlock(&dcache_lock);
spin_lock(&dcache_lock);
list_for_each_entry(loop, &dentry->d_subdirs,
d_u.d_child) {
- dentry_lru_del_init(loop);
+ dentry_lru_del(loop);
__d_drop(loop);
cond_resched_lock(&dcache_lock);
}
struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
next = tmp->next;
- dentry_lru_del_init(dentry);
/*
* move only zero ref count dentries to the end
* of the unused list for prune_dcache
*/
if (!atomic_read(&dentry->d_count)) {
- dentry_lru_add_tail(dentry);
+ dentry_lru_move_tail(dentry);
found++;
+ } else {
+ dentry_lru_del(dentry);
}
/*
* This is used by ncpfs in its readdir implementation.
* Zero is returned in the dentry is invalid.
*/
-
-int d_validate(struct dentry *dentry, struct dentry *dparent)
+int d_validate(struct dentry *dentry, struct dentry *parent)
{
- struct hlist_head *base;
- struct hlist_node *lhp;
+ struct hlist_head *head = d_hash(parent, dentry->d_name.hash);
+ struct hlist_node *node;
+ struct dentry *d;
/* Check whether the ptr might be valid at all.. */
if (!kmem_ptr_validate(dentry_cache, dentry))
- goto out;
-
- if (dentry->d_parent != dparent)
- goto out;
+ return 0;
+ if (dentry->d_parent != parent)
+ return 0;
- spin_lock(&dcache_lock);
- base = d_hash(dparent, dentry->d_name.hash);
- hlist_for_each(lhp,base) {
- /* 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)) {
- __dget_locked(dentry);
- spin_unlock(&dcache_lock);
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(d, node, head, d_hash) {
+ if (d == dentry) {
+ dget(dentry);
return 1;
}
}
- spin_unlock(&dcache_lock);
-out:
+ rcu_read_unlock();
return 0;
}
EXPORT_SYMBOL(d_validate);
git.openpandora.org / pandora-kernel.git / blobdiff