dentry: Rework dentry references and destruction

Now dentries default to d_ref = 0, and there's a way to lock references out. Signed-off-by: Pedro Falcato <[email protected]>
heatd · Aug 3, 2024 · 7cefbb0 · 7cefbb0
1 parent cf39338
commit 7cefbb0
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Showing 13 changed files with 277 additions and 132 deletions.
diff --git a/kernel/include/onyx/atomic.h b/kernel/include/onyx/atomic.h
@@ -16,4 +16,10 @@
 #define atomic_and_relaxed(var, mask) (__atomic_and_fetch(&(var), mask, __ATOMIC_RELAXED))
 #define atomic_or_relaxed(var, mask)  (__atomic_or_fetch(&(var), mask, __ATOMIC_RELAXED))
 
+#define cmpxchg(ptr, old, new)                                                                    \
+    ({                                                                                            \
+        __auto_type __old = (old);                                                                \
+        __atomic_compare_exchange_n(ptr, &__old, new, false, __ATOMIC_SEQ_CST, __ATOMIC_RELAXED); \
+        __old;                                                                                    \
+    })
 #endif
diff --git a/kernel/include/onyx/dentry.h b/kernel/include/onyx/dentry.h
@@ -38,6 +38,8 @@ struct dentry_operations
     int (*d_revalidate)(struct dentry *, unsigned int flags);
 };
 
+#define D_REF_LOCKED (1UL << 63)
+
 struct dentry
 {
     unsigned long d_ref;
@@ -66,8 +68,8 @@ struct dentry
 struct dentry *dentry_open(char *path, struct dentry *base);
 struct dentry *dentry_mount(const char *mountpoint, struct inode *inode);
 void dentry_init();
-void dentry_put(struct dentry *d);
-void dentry_get(struct dentry *d);
+void dput(struct dentry *d);
+void dget(struct dentry *d);
 struct inode;
 struct dentry *dentry_create(const char *name, struct inode *inode, struct dentry *parent,
                              u16 flags
@@ -128,13 +130,13 @@ class auto_dentry
     void ref() const
     {
         if (d)
-            dentry_get(d);
+            dget(d);
     }
 
     void unref() const
     {
         if (d)
-            dentry_put(d);
+            dput(d);
     }
 
 public:
@@ -147,7 +149,7 @@ class auto_dentry
     ~auto_dentry()
     {
         if (d)
-            dentry_put(d);
+            dput(d);
     }
 
     auto_dentry &operator=(const auto_dentry &rhs)

diff --git a/kernel/include/onyx/path.h b/kernel/include/onyx/path.h
@@ -19,14 +19,14 @@ struct path
 
 static inline void path_get(struct path *p)
 {
-    dentry_get(p->dentry);
+    dget(p->dentry);
     mnt_get(p->mount);
 }
 
 static inline void path_put(struct path *p)
 {
     if (p->dentry)
-        dentry_put(p->dentry);
+        dput(p->dentry);
     if (p->mount)
         mnt_put(p->mount);
 }