From: Allison Henderson Subject: [Ext4 punch hole 2/5 v7] Ext4 Punch Hole Support: Clear Hole Date: Sat, 07 May 2011 16:54:02 -0700 Message-ID: <4DC5DB9A.3030001@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: Ext4 Developers List Return-path: Received: from e6.ny.us.ibm.com ([32.97.182.146]:57483 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756389Ab1EGXyJ (ORCPT ); Sat, 7 May 2011 19:54:09 -0400 Received: from d01relay05.pok.ibm.com (d01relay05.pok.ibm.com [9.56.227.237]) by e6.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p47NTuWr032296 for ; Sat, 7 May 2011 19:29:56 -0400 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay05.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p47Ns8Rm106074 for ; Sat, 7 May 2011 19:54:08 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p47Ns8xs020791 for ; Sat, 7 May 2011 19:54:08 -0400 Received: from [9.48.112.215] (sig-9-48-112-215.mts.ibm.com [9.48.112.215]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id p47Ns7Pg020787 for ; Sat, 7 May 2011 19:54:07 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: This patch adds routines needed to zero out the unblock aligned data of the hole. The existing ext4_block_truncate_page routine that is used to zero out unblock aligned data from truncate has been modified to accept a length parameter, and renamed to ext4_block_zero_page_range. The function can now be used to zero out the head of a block, the tail of a block, or the middle of a block. The existing ext4_block_truncate_page has now become a wrapper to this function Signed-off-by: Allison Henderson --- :100644 100644 3ba6c31... 95efb4e... M fs/ext4/ext4.h :100644 100644 f92c58b... 8ce382d... M fs/ext4/inode.c fs/ext4/ext4.h | 2 ++ fs/ext4/inode.c | 33 +++++++++++++++++++++++++++++++-- 2 files changed, 33 insertions(+), 2 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 3ba6c31..95efb4e 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1758,6 +1758,8 @@ extern int ext4_writepage_trans_blocks(struct inode *); extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks); extern int ext4_block_truncate_page(handle_t *handle, struct address_space *mapping, loff_t from); +extern int ext4_block_zero_page_range(handle_t *handle, + struct address_space *mapping, loff_t from, loff_t length); extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf); extern qsize_t *ext4_get_reserved_space(struct inode *inode); extern void ext4_da_update_reserve_space(struct inode *inode, diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index f92c58b..8ce382d 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3916,9 +3916,30 @@ void ext4_set_aops(struct inode *inode) int ext4_block_truncate_page(handle_t *handle, struct address_space *mapping, loff_t from) { + unsigned offset = from & (PAGE_CACHE_SIZE-1); + unsigned length; + unsigned blocksize; + struct inode *inode = mapping->host; + + blocksize = inode->i_sb->s_blocksize; + length = blocksize - (offset & (blocksize - 1)); + + return ext4_block_zero_page_range(handle, mapping, from, length); +} + +/* + * ext4_block_zero_page_range() zeros out a mapping of length 'length' + * starting from file offset 'from'. The range to be zero'd must + * be contained with in one block. If the specified range exceeds + * the end of the block it will be shortened to end of the block + * that cooresponds to 'from' + */ +int ext4_block_zero_page_range(handle_t *handle, + struct address_space *mapping, loff_t from, loff_t length) +{ ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT; unsigned offset = from & (PAGE_CACHE_SIZE-1); - unsigned blocksize, length, pos; + unsigned blocksize, max, pos; ext4_lblk_t iblock; struct inode *inode = mapping->host; struct buffer_head *bh; @@ -3931,7 +3952,15 @@ int ext4_block_truncate_page(handle_t *handle, return -EINVAL; blocksize = inode->i_sb->s_blocksize; - length = blocksize - (offset & (blocksize - 1)); + max = blocksize - (offset & (blocksize - 1)); + + /* + * correct length if it does not fall between + * 'from' and the end of the block + */ + if (length > max || length < 0) + length = max; + iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); if (!page_has_buffers(page)) -- 1.7.1