Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932298AbaGVTx1 (ORCPT ); Tue, 22 Jul 2014 15:53:27 -0400 Received: from mga01.intel.com ([192.55.52.88]:60713 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932186AbaGVTxY (ORCPT ); Tue, 22 Jul 2014 15:53:24 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,711,1400050800"; d="scan'208";a="565652153" From: Matthew Wilcox To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Matthew Wilcox , willy@linux.intel.com, Ross Zwisler Subject: [PATCH v8 20/22] xip: Add xip_zero_page_range Date: Tue, 22 Jul 2014 15:48:08 -0400 Message-Id: <62c1760bda1cbf0577d67c27318e4467a8da4b03.1406058387.git.matthew.r.wilcox@intel.com> X-Mailer: git-send-email 2.0.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This new function allows us to support hole-punch for XIP files by zeroing a partial page, as opposed to the xip_truncate_page() function which can only truncate to the end of the page. Reimplement xip_truncate_page() as a macro that calls xip_zero_page_range(). Signed-off-by: Matthew Wilcox [ported to 3.13-rc2] Signed-off-by: Ross Zwisler --- Documentation/filesystems/dax.txt | 1 + fs/dax.c | 20 ++++++++++++++------ include/linux/fs.h | 9 ++++++++- 3 files changed, 23 insertions(+), 7 deletions(-) diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt index 6441766..1fd3a6f 100644 --- a/Documentation/filesystems/dax.txt +++ b/Documentation/filesystems/dax.txt @@ -62,6 +62,7 @@ Filesystem support consists of for fault and page_mkwrite (which should probably call dax_fault() and dax_mkwrite(), passing the appropriate get_block() callback) - calling dax_truncate_page() instead of block_truncate_page() for DAX files +- calling dax_zero_page_range() instead of zero_user() for DAX files - ensuring that there is sufficient locking between reads, writes, truncates and page faults diff --git a/fs/dax.c b/fs/dax.c index b9bc5e2..39b95b1 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -451,13 +451,16 @@ int dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, EXPORT_SYMBOL_GPL(dax_mkwrite); /** - * dax_truncate_page - handle a partial page being truncated in a DAX file + * dax_zero_page_range - zero a range within a page of a DAX file * @inode: The file being truncated * @from: The file offset that is being truncated to + * @length: The number of bytes to zero * @get_block: The filesystem method used to translate file offsets to blocks * - * Similar to block_truncate_page(), this function can be called by a - * filesystem when it is truncating an DAX file to handle the partial page. + * This function can be called by a filesystem when it is zeroing part of a + * page in a DAX file. This is intended for hole-punch operations. If + * you are truncating a file, the helper function dax_truncate_page() may be + * more convenient. * * We work in terms of PAGE_CACHE_SIZE here for commonality with * block_truncate_page(), but we could go down to PAGE_SIZE if the filesystem @@ -465,12 +468,12 @@ EXPORT_SYMBOL_GPL(dax_mkwrite); * block size is smaller than PAGE_SIZE, we have to zero the rest of the page * since the file might be mmaped. */ -int dax_truncate_page(struct inode *inode, loff_t from, get_block_t get_block) +int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length, + get_block_t get_block) { struct buffer_head bh; pgoff_t index = from >> PAGE_CACHE_SHIFT; unsigned offset = from & (PAGE_CACHE_SIZE-1); - unsigned length = PAGE_CACHE_ALIGN(from) - from; int err; /* Block boundary? Nothing to do */ @@ -487,9 +490,14 @@ int dax_truncate_page(struct inode *inode, loff_t from, get_block_t get_block) err = dax_get_addr(&bh, &addr, inode->i_blkbits); if (err < 0) return err; + /* + * ext4 sometimes asks to zero past the end of a block. It + * really just wants to zero to the end of the block. + */ + length = min_t(unsigned, length, PAGE_CACHE_SIZE - offset); memset(addr + offset, 0, length); } return 0; } -EXPORT_SYMBOL_GPL(dax_truncate_page); +EXPORT_SYMBOL_GPL(dax_zero_page_range); diff --git a/include/linux/fs.h b/include/linux/fs.h index a75a045..44facd9 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2463,6 +2463,7 @@ extern int nonseekable_open(struct inode * inode, struct file * filp); #ifdef CONFIG_FS_DAX int dax_clear_blocks(struct inode *, sector_t block, long size); +int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t); int dax_truncate_page(struct inode *, loff_t from, get_block_t); ssize_t dax_do_io(int rw, struct kiocb *, struct inode *, struct iov_iter *, loff_t, get_block_t, dio_iodone_t, int flags); @@ -2474,7 +2475,8 @@ static inline int dax_clear_blocks(struct inode *i, sector_t blk, long sz) return 0; } -static inline int dax_truncate_page(struct inode *i, loff_t frm, get_block_t gb) +static inline int dax_zero_page_range(struct inode *inode, loff_t from, + unsigned len, get_block_t gb) { return 0; } @@ -2487,6 +2489,11 @@ static inline ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode, } #endif +/* Can't be a function because PAGE_CACHE_SIZE is defined in pagemap.h */ +#define dax_truncate_page(inode, from, get_block) \ + dax_zero_page_range(inode, from, PAGE_CACHE_SIZE, get_block) + + #ifdef CONFIG_BLOCK typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode, loff_t file_offset); -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/