vfs: new d_init method

[cascardo/linux.git] / include / linux / dcache.h

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 0f9a977..98044a8 100644 (file)
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -98,7 +98,10 @@ struct dentry {
        unsigned long d_time;           /* used by d_revalidate */
        void *d_fsdata;                 /* fs-specific data */
 
-       struct list_head d_lru;         /* LRU list */
+       union {
+               struct list_head d_lru;         /* LRU list */
+               wait_queue_head_t *d_wait;      /* in-lookup ones only */
+       };
        struct list_head d_child;       /* child of parent list */
        struct list_head d_subdirs;     /* our children */
        /*
@@ -106,6 +109,7 @@ struct dentry {
         */
        union {
                struct hlist_node d_alias;      /* inode alias list */
+               struct hlist_bl_node d_in_lookup_hash;  /* only for in-lookup ones */
                struct rcu_head d_rcu;
        } d_u;
 };
@@ -129,14 +133,15 @@ struct dentry_operations {
        int (*d_compare)(const struct dentry *, const struct dentry *,
                        unsigned int, const char *, const struct qstr *);
        int (*d_delete)(const struct dentry *);
+       int (*d_init)(struct dentry *);
        void (*d_release)(struct dentry *);
        void (*d_prune)(struct dentry *);
        void (*d_iput)(struct dentry *, struct inode *);
        char *(*d_dname)(struct dentry *, char *, int);
        struct vfsmount *(*d_automount)(struct path *);
        int (*d_manage)(struct dentry *, bool);
-       struct inode *(*d_select_inode)(struct dentry *, unsigned);
-       struct dentry *(*d_real)(struct dentry *, struct inode *);
+       struct dentry *(*d_real)(struct dentry *, const struct inode *,
+                                unsigned int);
 } ____cacheline_aligned;
 
 /*
@@ -202,10 +207,11 @@ struct dentry_operations {
 
 #define DCACHE_MAY_FREE                        0x00800000
 #define DCACHE_FALLTHRU                        0x01000000 /* Fall through to lower layer */
-#define DCACHE_OP_SELECT_INODE         0x02000000 /* Unioned entry: dcache op selects inode */
+#define DCACHE_ENCRYPTED_WITH_KEY      0x02000000 /* dir is encrypted with a valid key */
+#define DCACHE_OP_REAL                 0x04000000
 
-#define DCACHE_ENCRYPTED_WITH_KEY      0x04000000 /* dir is encrypted with a valid key */
-#define DCACHE_OP_REAL                 0x08000000
+#define DCACHE_PAR_LOOKUP              0x10000000 /* being looked up (with parent locked shared) */
+#define DCACHE_DENTRY_CURSOR           0x20000000
 
 extern seqlock_t rename_lock;
 
@@ -223,6 +229,8 @@ extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op
 /* allocate/de-allocate */
 extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
 extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
+extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
+                                       wait_queue_head_t *);
 extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
 extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
 extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
@@ -342,6 +350,22 @@ static inline void dont_mount(struct dentry *dentry)
        spin_unlock(&dentry->d_lock);
 }
 
+extern void __d_lookup_done(struct dentry *);
+
+static inline int d_in_lookup(struct dentry *dentry)
+{
+       return dentry->d_flags & DCACHE_PAR_LOOKUP;
+}
+
+static inline void d_lookup_done(struct dentry *dentry)
+{
+       if (unlikely(d_in_lookup(dentry))) {
+               spin_lock(&dentry->d_lock);
+               __d_lookup_done(dentry);
+               spin_unlock(&dentry->d_lock);
+       }
+}
+
 extern void dput(struct dentry *);
 
 static inline bool d_managed(const struct dentry *dentry)
@@ -532,23 +556,37 @@ static inline struct dentry *d_backing_dentry(struct dentry *upper)
        return upper;
 }
 
-static inline struct dentry *d_real(struct dentry *dentry)
+/**
+ * d_real - Return the real dentry
+ * @dentry: the dentry to query
+ * @inode: inode to select the dentry from multiple layers (can be NULL)
+ * @flags: open flags to control copy-up behavior
+ *
+ * If dentry is on an union/overlay, then return the underlying, real dentry.
+ * Otherwise return the dentry itself.
+ *
+ * See also: Documentation/filesystems/vfs.txt
+ */
+static inline struct dentry *d_real(struct dentry *dentry,
+                                   const struct inode *inode,
+                                   unsigned int flags)
 {
        if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
-               return dentry->d_op->d_real(dentry, NULL);
+               return dentry->d_op->d_real(dentry, inode, flags);
        else
                return dentry;
 }
 
-static inline struct inode *vfs_select_inode(struct dentry *dentry,
-                                            unsigned open_flags)
+/**
+ * d_real_inode - Return the real inode
+ * @dentry: The dentry to query
+ *
+ * If dentry is on an union/overlay, then return the underlying, real inode.
+ * Otherwise return d_inode().
+ */
+static inline struct inode *d_real_inode(struct dentry *dentry)
 {
-       struct inode *inode = d_inode(dentry);
-
-       if (inode && unlikely(dentry->d_flags & DCACHE_OP_SELECT_INODE))
-               inode = dentry->d_op->d_select_inode(dentry, open_flags);
-
-       return inode;
+       return d_backing_inode(d_real(dentry, NULL, 0));
 }