From abd988c41bb537a6ab20fbe421d0bd280972c0f4 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@home.transmeta.com>
Date: Tue, 2 Jul 2002 01:37:41 -0700
Subject: [PATCH] Make ramfs/driverfs maintain directory nlink counts.

Make dcache filesystems export directory entry types
to readdir.
---
 fs/driverfs/inode.c | 26 ++++++++++++++++++--------
 fs/libfs.c          |  8 +++++++-
 fs/ramfs/inode.c    | 32 +++++++++++++++++++++++---------
 include/linux/fs.h  |  3 +++
 4 files changed, 51 insertions(+), 18 deletions(-)

diff --git a/fs/driverfs/inode.c b/fs/driverfs/inode.c
index 73ad5c1f6adb..2fd9126199b2 100644
--- a/fs/driverfs/inode.c
+++ b/fs/driverfs/inode.c
@@ -149,6 +149,10 @@ static int driverfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 	lock_kernel();
 	dentry->d_op = &driverfs_dentry_dir_ops;
  	res = driverfs_mknod(dir, dentry, mode | S_IFDIR, 0);
+ 	if (!res) {
+ 		dir->i_nlink++;
+ 		dentry->d_inode->i_nlink++;
+ 	}
 	unlock_kernel();
 	return res;
 }
@@ -205,23 +209,29 @@ static int driverfs_empty(struct dentry *dentry)
 }
 
 static int driverfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+
+	lock_kernel();
+	inode->i_nlink--;
+	unlock_kernel();
+	dput(dentry);
+	return 0;
+}
+
+static int driverfs_rmdir(struct inode *dir, struct dentry *dentry)
 {
 	int error = -ENOTEMPTY;
 
 	if (driverfs_empty(dentry)) {
-		struct inode *inode = dentry->d_inode;
-
-		lock_kernel();
-		inode->i_nlink--;
-		unlock_kernel();
-		dput(dentry);
+		dentry->d_inode->i_nlink--;
+		driverfs_unlink(dir, dentry);
+		dir->i_nlink--;
 		error = 0;
 	}
 	return error;
 }
 
-#define driverfs_rmdir driverfs_unlink
-
 /**
  * driverfs_read_file - "read" data from a file.
  * @file:	file pointer
diff --git a/fs/libfs.c b/fs/libfs.c
index f4b12699b37a..be9a8f7963e8 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -83,6 +83,12 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
 	return offset;
 }
 
+/* Relationship between i_mode and the DT_xxx types */
+static inline unsigned char dt_type(struct inode *inode)
+{
+	return (inode->i_mode >> 12) & 15;
+}
+
 /*
  * Directory is locked and all positive dentries in it are safe, since
  * for ramfs-type trees they can't go away without unlink() or rmdir(),
@@ -125,7 +131,7 @@ int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
 					continue;
 
 				spin_unlock(&dcache_lock);
-				if (filldir(dirent, next->d_name.name, next->d_name.len, filp->f_pos, next->d_inode->i_ino, DT_UNKNOWN) < 0)
+				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);
 				/* next is still alive */
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index d3edc3128ec0..7d41fc6389f2 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -130,7 +130,12 @@ static int ramfs_mknod(struct inode *dir, struct dentry *dentry, int mode, int d
 
 static int ramfs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
 {
-	return ramfs_mknod(dir, dentry, mode | S_IFDIR, 0);
+	int retval = ramfs_mknod(dir, dentry, mode | S_IFDIR, 0);
+	if (!retval) {
+		dir->i_nlink++;
+		dentry->d_inode->i_nlink++;
+	}
+	return retval;
 }
 
 static int ramfs_create(struct inode *dir, struct dentry *dentry, int mode)
@@ -186,25 +191,30 @@ static int ramfs_empty(struct dentry *dentry)
 }
 
 /*
- * This works for both directories and regular files.
- * (non-directories will always have empty subdirs)
+ * Unlink a ramfs entry
  */
 static int ramfs_unlink(struct inode * dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+
+	inode->i_nlink--;
+	dput(dentry);			/* Undo the count from "create" - this does all the work */
+	return 0;
+}
+
+static int ramfs_rmdir(struct inode * dir, struct dentry *dentry)
 {
 	int retval = -ENOTEMPTY;
 
 	if (ramfs_empty(dentry)) {
-		struct inode *inode = dentry->d_inode;
-
-		inode->i_nlink--;
-		dput(dentry);			/* Undo the count from "create" - this does all the work */
+		dentry->d_inode->i_nlink--;
+		ramfs_unlink(dir, dentry);
+		dir->i_nlink--;
 		retval = 0;
 	}
 	return retval;
 }
 
-#define ramfs_rmdir ramfs_unlink
-
 /*
  * The VFS layer already does all the dentry stuff for rename,
  * we just have to decrement the usage count for the target if
@@ -221,6 +231,10 @@ static int ramfs_rename(struct inode * old_dir, struct dentry *old_dentry, struc
 			inode->i_nlink--;
 			dput(new_dentry);
 		}
+		if (S_ISDIR(old_dentry->d_inode->i_mode)) {
+			old_dir->i_nlink--;
+			new_dir->i_nlink++;
+		}
 		error = 0;
 	}
 	return error;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 322e644060cf..002e02289155 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -701,6 +701,9 @@ extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct de
 
 /*
  * File types
+ *
+ * NOTE! These match bits 12..15 of stat.st_mode
+ * (ie "(i_mode >> 12) & 15").
  */
 #define DT_UNKNOWN	0
 #define DT_FIFO		1
-- 
2.39.5