From 7aa123a0dc3a856ef5e6f015571f11cd70b77213 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu, 16 May 2013 01:41:10 -0400
Subject: [PATCH] [readdir] convert efs

* sanity checks belong before risky operation, not after it
* don't quit as soon as we'd found an entry

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/efs/dir.c | 75 +++++++++++++++++++++++-----------------------------
 1 file changed, 33 insertions(+), 42 deletions(-)

diff --git a/fs/efs/dir.c b/fs/efs/dir.c
index 055a9e9ca747..b72307ccdf7a 100644
--- a/fs/efs/dir.c
+++ b/fs/efs/dir.c
@@ -7,40 +7,38 @@
 #include <linux/buffer_head.h>
 #include "efs.h"
 
-static int efs_readdir(struct file *, void *, filldir_t);
+static int efs_readdir(struct file *, struct dir_context *);
 
 const struct file_operations efs_dir_operations = {
 	.llseek		= generic_file_llseek,
 	.read		= generic_read_dir,
-	.readdir	= efs_readdir,
+	.iterate	= efs_readdir,
 };
 
 const struct inode_operations efs_dir_inode_operations = {
 	.lookup		= efs_lookup,
 };
 
-static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) {
-	struct inode *inode = file_inode(filp);
-	struct buffer_head *bh;
-
-	struct efs_dir		*dirblock;
-	struct efs_dentry	*dirslot;
-	efs_ino_t		inodenum;
+static int efs_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
 	efs_block_t		block;
-	int			slot, namelen;
-	char			*nameptr;
+	int			slot;
 
 	if (inode->i_size & (EFS_DIRBSIZE-1))
 		printk(KERN_WARNING "EFS: WARNING: readdir(): directory size not a multiple of EFS_DIRBSIZE\n");
 
 	/* work out where this entry can be found */
-	block = filp->f_pos >> EFS_DIRBSIZE_BITS;
+	block = ctx->pos >> EFS_DIRBSIZE_BITS;
 
 	/* each block contains at most 256 slots */
-	slot  = filp->f_pos & 0xff;
+	slot  = ctx->pos & 0xff;
 
 	/* look at all blocks */
 	while (block < inode->i_blocks) {
+		struct efs_dir		*dirblock;
+		struct buffer_head *bh;
+
 		/* read the dir block */
 		bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
 
@@ -57,11 +55,14 @@ static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) {
 			break;
 		}
 
-		while (slot < dirblock->slots) {
-			if (dirblock->space[slot] == 0) {
-				slot++;
+		for (; slot < dirblock->slots; slot++) {
+			struct efs_dentry *dirslot;
+			efs_ino_t inodenum;
+			const char *nameptr;
+			int namelen;
+
+			if (dirblock->space[slot] == 0)
 				continue;
-			}
 
 			dirslot  = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
 
@@ -72,39 +73,29 @@ static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) {
 #ifdef DEBUG
 			printk(KERN_DEBUG "EFS: readdir(): block %d slot %d/%d: inode %u, name \"%s\", namelen %u\n", block, slot, dirblock->slots-1, inodenum, nameptr, namelen);
 #endif
-			if (namelen > 0) {
-				/* found the next entry */
-				filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
-
-				/* copy filename and data in dirslot */
-				filldir(dirent, nameptr, namelen, filp->f_pos, inodenum, DT_UNKNOWN);
-
-				/* sanity check */
-				if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
-					printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot);
-					slot++;
-					continue;
-				}
-
-				/* store position of next slot */
-				if (++slot == dirblock->slots) {
-					slot = 0;
-					block++;
-				}
+			if (!namelen)
+				continue;
+			/* found the next entry */
+			ctx->pos = (block << EFS_DIRBSIZE_BITS) | slot;
+
+			/* sanity check */
+			if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
+				printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot);
+				continue;
+			}
+
+			/* copy filename and data in dirslot */
+			if (!dir_emit(ctx, nameptr, namelen, inodenum, DT_UNKNOWN)) {
 				brelse(bh);
-				filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
-				goto out;
+				return 0;
 			}
-			slot++;
 		}
 		brelse(bh);
 
 		slot = 0;
 		block++;
 	}
-
-	filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
-out:
+	ctx->pos = (block << EFS_DIRBSIZE_BITS) | slot;
 	return 0;
 }
 
-- 
2.20.1