aufs: inode op, rename 1/2, intro

Implement i_op->rename().
This is a big monster and I don't like it.

In order to call d_move() in aufs lock section, FS_RENAME_DOES_D_MOVE is
set to fstype.f_flags.
Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

fs/aufs/dentry.h

@@ -78,6 +78,9 @@ void di_read_unlock(struct dentry *d, int flags);
 void di_downgrade_lock(struct dentry *d, int flags);
 void di_write_lock(struct dentry *d, unsigned int lsc);
 void di_write_unlock(struct dentry *d);
+void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir);
+void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir);
+void di_write_unlock2(struct dentry *d1, struct dentry *d2);
 
 struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex);
 aufs_bindex_t au_dbtail(struct dentry *dentry);

fs/aufs/dinfo.c

@@ -258,6 +258,47 @@ void di_write_unlock(struct dentry *d)
 	au_rw_write_unlock(&au_di(d)->di_rwsem);
 }
 
+void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir)
+{
+	AuDebugOn(d1 == d2
+		  || d_inode(d1) == d_inode(d2)
+		  || d1->d_sb != d2->d_sb);
+
+	if ((isdir && au_test_subdir(d1, d2))
+	    || d1 < d2) {
+		di_write_lock_child(d1);
+		di_write_lock_child2(d2);
+	} else {
+		di_write_lock_child(d2);
+		di_write_lock_child2(d1);
+	}
+}
+
+void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir)
+{
+	AuDebugOn(d1 == d2
+		  || d_inode(d1) == d_inode(d2)
+		  || d1->d_sb != d2->d_sb);
+
+	if ((isdir && au_test_subdir(d1, d2))
+	    || d1 < d2) {
+		di_write_lock_parent(d1);
+		di_write_lock_parent2(d2);
+	} else {
+		di_write_lock_parent(d2);
+		di_write_lock_parent2(d1);
+	}
+}
+
+void di_write_unlock2(struct dentry *d1, struct dentry *d2)
+{
+	di_write_unlock(d1);
+	if (d_inode(d1) == d_inode(d2))
+		au_rw_write_unlock(&au_di(d2)->di_rwsem);
+	else
+		di_write_unlock(d2);
+}
+
 /* ---------------------------------------------------------------------- */
 
 struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex)

fs/aufs/sbinfo.c

@@ -243,3 +243,38 @@ void aufs_write_unlock(struct dentry *dentry)
 	di_write_unlock(dentry);
 	si_write_unlock(dentry->d_sb);
 }
+
+int aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int flags)
+{
+	int err;
+	unsigned int sigen;
+	struct super_block *sb;
+
+	sb = d1->d_sb;
+	err = si_read_lock(sb, flags);
+	if (unlikely(err))
+		goto out;
+
+	di_write_lock2_child(d1, d2, au_ftest_lock(flags, DIRS));
+
+	if (au_ftest_lock(flags, GEN)) {
+		sigen = au_sigen(sb);
+		err = au_digen_test(d1, sigen);
+		AuDebugOn(!err && au_dbrange_test(d1));
+		if (!err) {
+			err = au_digen_test(d2, sigen);
+			AuDebugOn(!err && au_dbrange_test(d2));
+		}
+		if (unlikely(err))
+			aufs_read_and_write_unlock2(d1, d2);
+	}
+
+out:
+	return err;
+}
+
+void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2)
+{
+	di_write_unlock2(d1, d2);
+	si_read_unlock(d1->d_sb);
+}

fs/aufs/super.c

@@ -897,6 +897,8 @@ static void aufs_kill_sb(struct super_block *sb)
 
 struct file_system_type aufs_fs_type = {
 	.name		= AUFS_FSTYPE,
+	/* a race between rename and others */
+	.fs_flags	= FS_RENAME_DOES_D_MOVE,
 	.mount		= aufs_mount,
 	.kill_sb	= aufs_kill_sb,
 	/* no need to __module_get() and module_put(). */

fs/aufs/super.h

@@ -188,6 +188,8 @@ static inline unsigned char au_do_ftest_si(struct au_sbinfo *sbi,
 #define AuLock_IR		(1 << 1)	/* read-lock inode */
 #define AuLock_IW		(1 << 2)	/* write-lock inode */
 #define AuLock_FLUSH		(1 << 3)	/* wait for 'nowait' tasks */
+#define AuLock_DIRS		(1 << 4)	/* target is a pair of dirs */
+						/* except RENAME_EXCHANGE */
 #define AuLock_NOPLM		(1 << 5)	/* return err in plm mode */
 #define AuLock_NOPLMW		(1 << 6)	/* wait for plm mode ends */
 #define AuLock_GEN		(1 << 7)	/* test digen/iigen */
@@ -223,6 +225,8 @@ int aufs_read_lock(struct dentry *dentry, int flags);
 void aufs_read_unlock(struct dentry *dentry, int flags);
 void aufs_write_lock(struct dentry *dentry);
 void aufs_write_unlock(struct dentry *dentry);
+int aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int flags);
+void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2);
 
 /* wbr_policy.c */
 extern struct au_wbr_copyup_operations au_wbr_copyup_ops[];

fs/aufs/vfsub.c

@@ -101,6 +101,34 @@ void vfsub_call_lkup_one(void *args)
 
 /* ---------------------------------------------------------------------- */
 
+struct dentry *vfsub_lock_rename(struct dentry *d1, struct au_hinode *hdir1,
+				 struct dentry *d2, struct au_hinode *hdir2)
+{
+	struct dentry *d;
+
+	lockdep_off();
+	d = lock_rename(d1, d2);
+	lockdep_on();
+	au_hn_suspend(hdir1);
+	if (hdir1 != hdir2)
+		au_hn_suspend(hdir2);
+
+	return d;
+}
+
+void vfsub_unlock_rename(struct dentry *d1, struct au_hinode *hdir1,
+			 struct dentry *d2, struct au_hinode *hdir2)
+{
+	au_hn_resume(hdir1);
+	if (hdir1 != hdir2)
+		au_hn_resume(hdir2);
+	lockdep_off();
+	unlock_rename(d1, d2);
+	lockdep_on();
+}
+
+/* ---------------------------------------------------------------------- */
+
 int vfsub_create(struct inode *dir, struct path *path, int mode, bool want_excl)
 {
 	int err;

fs/aufs/vfsub.h

@@ -98,6 +98,12 @@ static inline void vfsub_mnt_drop_write(struct vfsmount *mnt)
 
 /* ---------------------------------------------------------------------- */
 
+struct au_hinode;
+struct dentry *vfsub_lock_rename(struct dentry *d1, struct au_hinode *hdir1,
+				 struct dentry *d2, struct au_hinode *hdir2);
+void vfsub_unlock_rename(struct dentry *d1, struct au_hinode *hdir1,
+			 struct dentry *d2, struct au_hinode *hdir2);
+
 int vfsub_create(struct inode *dir, struct path *path, int mode,
 		 bool want_excl);
 int vfsub_symlink(struct inode *dir, struct path *path,