Signed-off-by: Nick Piggin <[email protected]>
---
fs/dcache.c | 38 +++++++++++++++++++++-----------------
1 file changed, 21 insertions(+), 17 deletions(-)
Index: linux-2.6/fs/dcache.c
===================================================================
--- linux-2.6.orig/fs/dcache.c 2010-11-17 00:52:38.000000000 +1100
+++ linux-2.6/fs/dcache.c 2010-11-17 01:05:37.000000000 +1100
@@ -580,16 +580,16 @@ static void shrink_dentry_list(struct li
{
struct dentry *dentry;
+ rcu_read_lock();
while (!list_empty(list)) {
struct dentry *parent;
dentry = list_entry(list->prev, struct dentry, d_lru);
- if (!spin_trylock(&dentry->d_lock)) {
-relock1:
- spin_unlock(&dcache_lru_lock);
- cpu_relax();
- spin_lock(&dcache_lru_lock);
+ /* Don't need RCU dereference because we recheck under lock */
+ spin_lock(&dentry->d_lock);
+ if (dentry != list_entry(list->prev, struct dentry, d_lru)) {
+ spin_unlock(&dentry->d_lock);
continue;
}
@@ -599,14 +599,16 @@ static void shrink_dentry_list(struct li
* it - just keep it off the LRU list.
*/
if (dentry->d_count) {
- __dentry_lru_del(dentry);
+ dentry_lru_del(dentry);
spin_unlock(&dentry->d_lock);
continue;
}
+
if (!spin_trylock(&dcache_inode_lock)) {
-relock2:
+relock:
spin_unlock(&dentry->d_lock);
- goto relock1;
+ cpu_relax();
+ continue;
}
if (IS_ROOT(dentry))
parent = NULL;
@@ -614,15 +616,15 @@ static void shrink_dentry_list(struct li
parent = dentry->d_parent;
if (parent && !spin_trylock(&parent->d_lock)) {
spin_unlock(&dcache_inode_lock);
- goto relock2;
+ goto relock;
}
- __dentry_lru_del(dentry);
- spin_unlock(&dcache_lru_lock);
+ dentry_lru_del(dentry);
+ rcu_read_unlock();
prune_one_dentry(dentry, parent);
- /* dcache_inode_lock and dentry->d_lock dropped */
- spin_lock(&dcache_lru_lock);
+ rcu_read_lock();
}
+ rcu_read_unlock();
}
/**
@@ -671,13 +673,13 @@ static void __shrink_dcache_sb(struct su
break;
}
}
-
- *count = cnt;
- shrink_dentry_list(&tmp);
-
if (!list_empty(&referenced))
list_splice(&referenced, &sb->s_dentry_lru);
spin_unlock(&dcache_lru_lock);
+
+ shrink_dentry_list(&tmp);
+
+ *count = cnt;
}
/**
@@ -769,7 +771,9 @@ void shrink_dcache_sb(struct super_block
spin_lock(&dcache_lru_lock);
while (!list_empty(&sb->s_dentry_lru)) {
list_splice_init(&sb->s_dentry_lru, &tmp);
+ spin_unlock(&dcache_lru_lock);
shrink_dentry_list(&tmp);
+ spin_lock(&dcache_lru_lock);
}
spin_unlock(&dcache_lru_lock);
}