linux-ext4 - [PATCH 4/5 v6] ext4: fix fsx truncate failure

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Date:	Wed, 24 Aug 2011 12:07:21 -0700
From:	Allison Henderson <achender@...ux.vnet.ibm.com>
To:	linux-ext4@...r.kernel.org
Cc:	Allison Henderson <achender@...ux.vnet.ibm.com>
Subject: [PATCH 4/5 v6] ext4: fix fsx truncate failure

While running extended fsx tests to verify the first
two patches, a similar bug was also found in the
truncate operation

This bug happens because the truncate routine only zeros
the unblock aligned portion of the last page.  This means
that the block aligned portions of the page appearing after
i_size are left unzeroed, and the buffer heads still mapped.

This bug is corrected by using ext4_discard_partial_page_buffers
in the truncate routine to zero the partial page and unmap
the buffer headers

Signed-off-by: Allison Henderson <achender@...ux.vnet.ibm.com>
---
:100644 100644 3e87a43... 98a23b2... M	fs/ext4/extents.c
:100644 100644 b8602cd... c11bfcd... M	fs/ext4/indirect.c
 fs/ext4/extents.c  |   14 ++++++++++++--
 fs/ext4/indirect.c |   16 ++++++++++++++--
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 3e87a43..98a23b2 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3644,6 +3644,7 @@ void ext4_ext_truncate(struct inode *inode)
 	struct super_block *sb = inode->i_sb;
 	ext4_lblk_t last_block;
 	handle_t *handle;
+	loff_t page_len;
 	int err = 0;
 
 	/*
@@ -3660,8 +3661,17 @@ void ext4_ext_truncate(struct inode *inode)
 	if (IS_ERR(handle))
 		return;
 
-	if (inode->i_size & (sb->s_blocksize - 1))
-		ext4_block_truncate_page(handle, mapping, inode->i_size);
+	if (inode->i_size % PAGE_CACHE_SIZE != 0) {
+
+		page_len = PAGE_CACHE_SIZE -
+			(inode->i_size & (PAGE_CACHE_SIZE - 1));
+
+		err = ext4_discard_partial_page_buffers(handle,
+			mapping, inode->i_size, page_len, 0);
+
+		if (err)
+			goto out_stop;
+	}
 
 	if (ext4_orphan_add(handle, inode))
 		goto out_stop;
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index b8602cd..c11bfcd 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -1338,7 +1338,9 @@ void ext4_ind_truncate(struct inode *inode)
 	__le32 nr = 0;
 	int n = 0;
 	ext4_lblk_t last_block, max_block;
+	loff_t page_len;
 	unsigned blocksize = inode->i_sb->s_blocksize;
+	int err;
 
 	handle = start_transaction(inode);
 	if (IS_ERR(handle))
@@ -1349,9 +1351,19 @@ void ext4_ind_truncate(struct inode *inode)
 	max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
 					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
 
-	if (inode->i_size & (blocksize - 1))
-		if (ext4_block_truncate_page(handle, mapping, inode->i_size))
+
+	if (inode->i_size % PAGE_CACHE_SIZE != 0) {
+
+		page_len = PAGE_CACHE_SIZE -
+			(inode->i_size & (PAGE_CACHE_SIZE - 1));
+
+		err = ext4_discard_partial_page_buffers(handle,
+			mapping, inode->i_size, page_len, 0);
+
+		if (err)
 			goto out_stop;
+	}
+
 
 	if (last_block != max_block) {
 		n = ext4_block_to_path(inode, last_block, offsets, NULL);
-- 
1.7.1

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