return dentry->d_name.name != dentry->d_iname;
}
+/*
+ * Make sure other CPUs see the inode attached before the type is set.
+ */
+static inline void __d_set_inode_and_type(struct dentry *dentry,
+ struct inode *inode,
+ unsigned type_flags)
+{
+ unsigned flags;
+
+ dentry->d_inode = inode;
+ smp_wmb();
+ flags = READ_ONCE(dentry->d_flags);
+ flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
+ flags |= type_flags;
+ WRITE_ONCE(dentry->d_flags, flags);
+}
+
+/*
+ * Ideally, we want to make sure that other CPUs see the flags cleared before
+ * the inode is detached, but this is really a violation of RCU principles
+ * since the ordering suggests we should always set inode before flags.
+ *
+ * We should instead replace or discard the entire dentry - but that sucks
+ * performancewise on mass deletion/rename.
+ */
+static inline void __d_clear_type_and_inode(struct dentry *dentry)
+{
+ unsigned flags = READ_ONCE(dentry->d_flags);
+
+ flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
+ WRITE_ONCE(dentry->d_flags, flags);
+ smp_wmb();
+ dentry->d_inode = NULL;
+}
+
static void dentry_free(struct dentry *dentry)
{
WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias));
{
struct inode *inode = dentry->d_inode;
if (inode) {
- dentry->d_inode = NULL;
+ __d_clear_type_and_inode(dentry);
hlist_del_init(&dentry->d_u.d_alias);
spin_unlock(&dentry->d_lock);
spin_unlock(&inode->i_lock);
__releases(dentry->d_inode->i_lock)
{
struct inode *inode = dentry->d_inode;
- __d_clear_type(dentry);
- dentry->d_inode = NULL;
+ __d_clear_type_and_inode(dentry);
hlist_del_init(&dentry->d_u.d_alias);
dentry_rcuwalk_barrier(dentry);
spin_unlock(&dentry->d_lock);
}
EXPORT_SYMBOL(d_set_d_op);
+
+/*
+ * d_set_fallthru - Mark a dentry as falling through to a lower layer
+ * @dentry - The dentry to mark
+ *
+ * Mark a dentry as falling through to the lower layer (as set with
+ * d_pin_lower()). This flag may be recorded on the medium.
+ */
+void d_set_fallthru(struct dentry *dentry)
+{
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags |= DCACHE_FALLTHRU;
+ spin_unlock(&dentry->d_lock);
+}
+EXPORT_SYMBOL(d_set_fallthru);
+
static unsigned d_flags_for_inode(struct inode *inode)
{
- unsigned add_flags = DCACHE_FILE_TYPE;
+ unsigned add_flags = DCACHE_REGULAR_TYPE;
if (!inode)
return DCACHE_MISS_TYPE;
else
inode->i_opflags |= IOP_LOOKUP;
}
- } else if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
- if (unlikely(inode->i_op->follow_link))
+ goto type_determined;
+ }
+
+ if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
+ if (unlikely(inode->i_op->follow_link)) {
add_flags = DCACHE_SYMLINK_TYPE;
- else
- inode->i_opflags |= IOP_NOFOLLOW;
+ goto type_determined;
+ }
+ inode->i_opflags |= IOP_NOFOLLOW;
}
+ if (unlikely(!S_ISREG(inode->i_mode)))
+ add_flags = DCACHE_SPECIAL_TYPE;
+
+type_determined:
if (unlikely(IS_AUTOMOUNT(inode)))
add_flags |= DCACHE_NEED_AUTOMOUNT;
return add_flags;
unsigned add_flags = d_flags_for_inode(inode);
spin_lock(&dentry->d_lock);
- __d_set_type(dentry, add_flags);
if (inode)
hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
- dentry->d_inode = inode;
+ __d_set_inode_and_type(dentry, inode, add_flags);
dentry_rcuwalk_barrier(dentry);
spin_unlock(&dentry->d_lock);
fsnotify_d_instantiate(dentry, inode);
add_flags |= DCACHE_DISCONNECTED;
spin_lock(&tmp->d_lock);
- tmp->d_inode = inode;
- tmp->d_flags |= add_flags;
+ __d_set_inode_and_type(tmp, inode, add_flags);
hlist_add_head(&tmp->d_u.d_alias, &inode->i_dentry);
hlist_bl_lock(&tmp->d_sb->s_anon);
hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
struct dentry *dentry, struct dentry *alias)
{
struct mutex *m1 = NULL, *m2 = NULL;
- int ret = -EBUSY;
+ int ret = -ESTALE;
/* If alias and dentry share a parent, then no extra locks required */
if (alias->d_parent == dentry->d_parent)