From 10794d1410e477f3a81e912d4a22a7fecab6a6ca Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linuxfoundation.org>
Date: Fri, 23 Nov 2007 15:38:32 -0500
Subject: [PATCH]  - pre4:     - truncate really fixed this time. Everybody
 agrees.

---
 drivers/sound/nm256_audio.c |  2 +-
 fs/buffer.c                 | 27 ++++++++-------------------
 fs/ext2/inode.c             |  3 +--
 include/linux/fs.h          | 19 +++++++++++++++----
 4 files changed, 25 insertions(+), 26 deletions(-)

diff --git a/drivers/sound/nm256_audio.c b/drivers/sound/nm256_audio.c
index 9049b4ceaaa9..c41c858d085d 100644
--- a/drivers/sound/nm256_audio.c
+++ b/drivers/sound/nm256_audio.c
@@ -1467,7 +1467,7 @@ nm256_audio_ioctl(int dev, unsigned int cmd, caddr_t arg)
 	    break;
 
 	case SNDCTL_DSP_SETFMT:
-	    if (get_user(ret, (int *) arg)
+	    if (get_user(ret, (int *) arg))
 		return -EFAULT;
 
 	    if (ret != 0) {
diff --git a/fs/buffer.c b/fs/buffer.c
index b9120655e774..5ee5d376fdab 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1514,6 +1514,9 @@ static int __block_commit_write(struct inode *inode, struct page *page,
 	    bh != head || !block_start;
 	    block_start=block_end, bh = bh->b_this_page) {
 		block_end = block_start + blocksize;
+	    	/* This can happen for the truncate case */
+	    	if (!buffer_mapped(bh))
+	    		continue;
 		if (block_end <= from || block_start >= to) {
 			if (!buffer_uptodate(bh))
 				partial = 1;
@@ -1721,24 +1724,12 @@ int generic_commit_write(struct file *file, struct page *page,
 	return 0;
 }
 
-/*
- * If it would be '74 that would go into libc...
- */
-int mem_is_zero(char *p, unsigned len)
-{
-	while (len--)
-		if (*p++)
-			return 0;
-	return 1;
-}
-
 int block_zero_page(struct address_space *mapping, loff_t from, unsigned length)
 {
 	unsigned long index = from >> PAGE_CACHE_SHIFT;
 	unsigned offset = from & (PAGE_CACHE_SIZE-1);
 	struct inode *inode = (struct inode *)mapping->host;
 	struct page *page;
-	char *kaddr;
 	int err;
 
 	if (!length)
@@ -1747,21 +1738,19 @@ int block_zero_page(struct address_space *mapping, loff_t from, unsigned length)
 	page = read_cache_page(mapping, index,
 				(filler_t *)mapping->a_ops->readpage, NULL);
 	err = PTR_ERR(page);
-	if (ERR_PTR(page))
+	if (IS_ERR(page))
 		goto out;
 	lock_page(page);
 	err = -EIO;
 	if (!Page_Uptodate(page))
 		goto unlock;
-	kaddr = (char*)kmap(page);
-	err = 0;
-	if (mem_is_zero(kaddr+offset, length))
-		goto unmap;
-	memset(kaddr+offset, 0, length);
+
+	memset((char *) kmap(page) + offset, 0, length);
 	flush_dcache_page(page);
 	__block_commit_write(inode, page, offset, offset+length);
-unmap:
 	kunmap(page);
+	err = 0;
+
 unlock:
 	UnlockPage(page);
 	page_cache_release(page);
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index a6567685e9c5..6c89f5090424 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -919,8 +919,7 @@ void ext2_truncate (struct inode * inode)
 					>> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
 	tail = (iblock << EXT2_BLOCK_SIZE_BITS(inode->i_sb)) - inode->i_size;
 
-	if (block_zero_page(inode->i_mapping, inode->i_size, tail) != 0)
-		return;
+	block_zero_page(inode->i_mapping, inode->i_size, tail);
 
 	n = ext2_block_to_path(inode, iblock, offsets);
 	if (n == 0)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 17f2502cc141..15b5aa8886f1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1050,9 +1050,20 @@ extern ino_t find_inode_number(struct dentry *, struct qstr *);
  * This should be a per-architecture thing, to allow different
  * error and pointer decisions.
  */
-#define ERR_PTR(err)	((void *)((long)(err)))
-#define PTR_ERR(ptr)	((long)(ptr))
-#define IS_ERR(ptr)	((unsigned long)(ptr) > (unsigned long)(-1000))
+static inline void *ERR_PTR(long error)
+{
+	return (void *) error;
+}
+
+static inline long PTR_ERR(const void *ptr)
+{
+	return (long) ptr;
+}
+
+static inline long IS_ERR(const void *ptr)
+{
+	return (unsigned long)ptr > (unsigned long)-1000L;
+}
 
 /*
  * The bitmask for a lookup event:
@@ -1162,7 +1173,7 @@ extern int block_sync_page(struct page *);
 
 int generic_block_bmap(struct address_space *, long, get_block_t *);
 int generic_commit_write(struct file *, struct page *, unsigned, unsigned);
-int block_zero_page(struct address_space *mapping, loff_t, unsigned);
+int block_zero_page(struct address_space *, loff_t, unsigned);
 
 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
 extern ssize_t generic_file_read(struct file *, char *, size_t, loff_t *);
-- 
2.39.5