From 7071820357610414f4355f4af6cf9ece7a576df1 Mon Sep 17 00:00:00 2001
From: Allison Henderson <achender@linux.vnet.ibm.com>
Date: Sat, 3 Sep 2011 11:56:52 -0400
Subject: [PATCH] --- yaml --- r: 273098 b: refs/heads/master c:
 2be4751b21ae1cacb002da48cfc5bf6743fee8c1 h: refs/heads/master v: v3

---
 [refs]                  |  2 +-
 trunk/fs/ext4/extents.c | 41 +++++++++++++++++++++++++++++++++++++----
 2 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index d9d4b4c86aea..480e0cc1a144 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ba06208a1315ab2d2217e09c79582b886c9f629e
+refs/heads/master: 2be4751b21ae1cacb002da48cfc5bf6743fee8c1
diff --git a/trunk/fs/ext4/extents.c b/trunk/fs/ext4/extents.c
index 18f7e04a4fa3..9124cd24e093 100644
--- a/trunk/fs/ext4/extents.c
+++ b/trunk/fs/ext4/extents.c
@@ -4166,6 +4166,20 @@ int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length)
 	loff_t first_page_offset, last_page_offset;
 	int ret, credits, blocks_released, err = 0;
 
+	/* No need to punch hole beyond i_size */
+	if (offset >= inode->i_size)
+		return 0;
+
+	/*
+	 * If the hole extends beyond i_size, set the hole
+	 * to end after the page that contains i_size
+	 */
+	if (offset + length > inode->i_size) {
+		length = inode->i_size +
+		   PAGE_CACHE_SIZE - (inode->i_size & (PAGE_CACHE_SIZE - 1)) -
+		   offset;
+	}
+
 	first_block = (offset + sb->s_blocksize - 1) >>
 		EXT4_BLOCK_SIZE_BITS(sb);
 	last_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
@@ -4182,11 +4196,10 @@ int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length)
 	 */
 	if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
 		err = filemap_write_and_wait_range(mapping,
-			first_page_offset == 0 ? 0 : first_page_offset-1,
-			last_page_offset);
+			offset, offset + length - 1);
 
-			if (err)
-				return err;
+		if (err)
+			return err;
 	}
 
 	/* Now release the pages */
@@ -4249,6 +4262,26 @@ int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length)
 		}
 	}
 
+
+	/*
+	 * If i_size is contained in the last page, we need to
+	 * unmap and zero the partial page after i_size
+	 */
+	if (inode->i_size >> PAGE_CACHE_SHIFT == last_page &&
+	   inode->i_size % PAGE_CACHE_SIZE != 0) {
+
+		page_len = PAGE_CACHE_SIZE -
+			(inode->i_size & (PAGE_CACHE_SIZE - 1));
+
+		if (page_len > 0) {
+			err = ext4_discard_partial_page_buffers(handle,
+			  mapping, inode->i_size, page_len, 0);
+
+			if (err)
+				goto out;
+		}
+	}
+
 	/* If there are no blocks to remove, return now */
 	if (first_block >= last_block)
 		goto out;