[PATCH RFC 7/8] dcache: push releasing dentry lock into sweep_negative

[Konstantin Khlebnikov]

This is preparation for the next patch.

Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
---
 fs/dcache.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 0fd2e02e507b..60158065891e 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -636,15 +636,17 @@ static inline struct dentry *lock_parent(struct dentry 
*dentry)
  * Move cached negative dentry to the tail of parent->d_subdirs.
  * This lets walkers skip them all together at first sight.
  * Must be called at dput of negative dentry.
+ * dentry->d_lock must be held, returns with it unlocked.
  */
 static void sweep_negative(struct dentry *dentry)
+       __releases(dentry->d_lock)
 {
        struct dentry *parent;
 
        if (!d_is_tail_negative(dentry)) {
                parent = lock_parent(dentry);
                if (!parent)
-                       return;
+                       goto out;
 
                if (!d_count(dentry) && d_is_negative(dentry) &&
                    !d_is_tail_negative(dentry)) {
@@ -654,6 +656,8 @@ static void sweep_negative(struct dentry *dentry)
 
                spin_unlock(&parent->d_lock);
        }
+out:
+       spin_unlock(&dentry->d_lock);
 }
 
 /*
@@ -747,7 +751,8 @@ static struct dentry *dentry_kill(struct dentry *dentry)
                spin_unlock(&parent->d_lock);
        if (d_is_negative(dentry))
                sweep_negative(dentry);
-       spin_unlock(&dentry->d_lock);
+       else
+               spin_unlock(&dentry->d_lock);
        return NULL;
 }
 
@@ -905,7 +910,8 @@ void dput(struct dentry *dentry)
                if (likely(retain_dentry(dentry))) {
                        if (d_is_negative(dentry))
                                sweep_negative(dentry);
-                       spin_unlock(&dentry->d_lock);
+                       else
+                               spin_unlock(&dentry->d_lock);
                        return;
                }