1 files changed, 39 insertions, 24 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index a3accdf528ad..889311e3d06b 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -16,6 +16,11 @@
 
 #include <asm/uaccess.h>
 
+static inline int simple_positive(struct dentry *dentry)
+{
+        return dentry->d_inode && !d_unhashed(dentry);
+}
+
 int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
                    struct kstat *stat)
 {
@@ -37,7 +42,7 @@ int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
  * Retaining negative dentries for an in-memory filesystem just wastes
  * memory and lookup time: arrange for them to be deleted immediately.
  */
-static int simple_delete_dentry(struct dentry *dentry)
+static int simple_delete_dentry(const struct dentry *dentry)
 {
         return 1;
 }
@@ -54,7 +59,7 @@ struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct na
 
         if (dentry->d_name.len > NAME_MAX)
                 return ERR_PTR(-ENAMETOOLONG);
-        dentry->d_op = &simple_dentry_operations;
+        d_set_d_op(dentry, &simple_dentry_operations);
         d_add(dentry, NULL);
         return NULL;
 }
@@ -76,7 +81,8 @@ int dcache_dir_close(struct inode *inode, struct file *file)
 
 loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
 {
-        mutex_lock(&file->f_path.dentry->d_inode->i_mutex);
+        struct dentry *dentry = file->f_path.dentry;
+        mutex_lock(&dentry->d_inode->i_mutex);
         switch (origin) {
                 case 1:
                         offset += file->f_pos;
@@ -84,7 +90,7 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
                         if (offset >= 0)
                                 break;
                 default:
-                        mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
+                        mutex_unlock(&dentry->d_inode->i_mutex);
                         return -EINVAL;
         }
         if (offset != file->f_pos) {
@@ -94,21 +100,24 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
                         struct dentry *cursor = file->private_data;
                         loff_t n = file->f_pos - 2;
 
-                        spin_lock(&dcache_lock);
+                        spin_lock(&dentry->d_lock);
+                        /* d_lock not required for cursor */
                         list_del(&cursor->d_u.d_child);
-                        p = file->f_path.dentry->d_subdirs.next;
-                        while (n && p != &file->f_path.dentry->d_subdirs) {
+                        p = dentry->d_subdirs.next;
+                        while (n && p != &dentry->d_subdirs) {
                                 struct dentry *next;
                                 next = list_entry(p, struct dentry, d_u.d_child);
-                                if (!d_unhashed(next) && next->d_inode)
+                                spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
+                                if (simple_positive(next))
                                         n--;
+                                spin_unlock(&next->d_lock);
                                 p = p->next;
                         }
                         list_add_tail(&cursor->d_u.d_child, p);
-                        spin_unlock(&dcache_lock);
+                        spin_unlock(&dentry->d_lock);
                 }
         }
-        mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
+        mutex_unlock(&dentry->d_inode->i_mutex);
         return offset;
 }
 
@@ -148,29 +157,35 @@ int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
                         i++;
                         /* fallthrough */
                 default:
-                        spin_lock(&dcache_lock);
+                        spin_lock(&dentry->d_lock);
                         if (filp->f_pos == 2)
                                 list_move(q, &dentry->d_subdirs);
 
                         for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
                                 struct dentry *next;
                                 next = list_entry(p, struct dentry, d_u.d_child);
-                                if (d_unhashed(next) || !next->d_inode)
+                                spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
+                                if (!simple_positive(next)) {
+                                        spin_unlock(&next->d_lock);
                                         continue;
+                                }
 
-                                spin_unlock(&dcache_lock);
+                                spin_unlock(&next->d_lock);
+                                spin_unlock(&dentry->d_lock);
                                 if (filldir(dirent, next->d_name.name, 
                                             next->d_name.len, filp->f_pos, 
                                             next->d_inode->i_ino, 
                                             dt_type(next->d_inode)) < 0)
                                         return 0;
-                                spin_lock(&dcache_lock);
+                                spin_lock(&dentry->d_lock);
+                                spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
                                 /* next is still alive */
                                 list_move(q, p);
+                                spin_unlock(&next->d_lock);
                                 p = q;
                                 filp->f_pos++;
                         }
-                        spin_unlock(&dcache_lock);
+                        spin_unlock(&dentry->d_lock);
         }
         return 0;
 }
@@ -259,23 +274,23 @@ int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *den
         return 0;
 }
 
-static inline int simple_positive(struct dentry *dentry)
-{
-        return dentry->d_inode && !d_unhashed(dentry);
-}
-
 int simple_empty(struct dentry *dentry)
 {
         struct dentry *child;
         int ret = 0;
 
-        spin_lock(&dcache_lock);
-        list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
-                if (simple_positive(child))
+        spin_lock(&dentry->d_lock);
+        list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) {
+                spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
+                if (simple_positive(child)) {
+                        spin_unlock(&child->d_lock);
                         goto out;
+                }
+                spin_unlock(&child->d_lock);
+        }
         ret = 1;
 out:
-        spin_unlock(&dcache_lock);
+        spin_unlock(&dentry->d_lock);
         return ret;
 }