From: Matthew Wilcox Subject: [PATCH v4 17/22] xip: Add xip_zero_page_range Date: Sun, 22 Dec 2013 16:49:44 -0500 Message-ID: References: Cc: Matthew Wilcox , Ross Zwisler To: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org Return-path: Received: from mga02.intel.com ([134.134.136.20]:21055 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755924Ab3LVVun (ORCPT ); Sun, 22 Dec 2013 16:50:43 -0500 In-Reply-To: In-Reply-To: References: Sender: linux-ext4-owner@vger.kernel.org List-ID: 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 --- fs/xip.c | 15 +++++++++------ include/linux/fs.h | 11 +++++++++-- 2 files changed, 18 insertions(+), 8 deletions(-) diff --git a/fs/xip.c b/fs/xip.c index 991a705..e6e52ee 100644 --- a/fs/xip.c +++ b/fs/xip.c @@ -274,13 +274,16 @@ int xip_fault(struct vm_area_struct *vma, struct vm_fault *vmf, EXPORT_SYMBOL_GPL(xip_fault); /** - * xip_truncate_page - handle a partial page being truncated in an XIP file + * xip_zero_page_range - zero a range within a page of an XIP 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 get blocks * - * Similar to block_truncate_page(), this function can be called by a - * filesystem when it is truncating an XIP file to handle the partial page. + * This function can be called by a filesystem when it is zeroing part of a + * page in an XIP file. This is intended for hole-punch operations. If + * you are truncating a file, the helper function xip_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 @@ -288,12 +291,12 @@ EXPORT_SYMBOL_GPL(xip_fault); * block size is smaller than PAGE_SIZE, we have to zero the rest of the page * since the file might be mmaped. */ -int xip_truncate_page(struct inode *inode, loff_t from, get_block_t get_block) +int xip_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 */ @@ -315,4 +318,4 @@ int xip_truncate_page(struct inode *inode, loff_t from, get_block_t get_block) return 0; } -EXPORT_SYMBOL_GPL(xip_truncate_page); +EXPORT_SYMBOL_GPL(xip_zero_page_range); diff --git a/include/linux/fs.h b/include/linux/fs.h index a0c6812..3a4a217 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2509,7 +2509,7 @@ extern int nonseekable_open(struct inode * inode, struct file * filp); #ifdef CONFIG_FS_XIP int xip_clear_blocks(struct inode *, sector_t block, long size); -int xip_truncate_page(struct inode *, loff_t from, get_block_t); +int xip_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t); ssize_t xip_do_io(int rw, struct kiocb *, struct inode *, const struct iovec *, loff_t, unsigned segs, get_block_t, dio_iodone_t, int flags); int xip_fault(struct vm_area_struct *, struct vm_fault *, get_block_t); @@ -2519,7 +2519,8 @@ static inline int xip_clear_blocks(struct inode *i, sector_t blk, long sz) return 0; } -static inline int xip_truncate_page(struct inode *i, loff_t frm, get_block_t gb) +static inline int xip_zero_page_range(struct inode *inode, loff_t from, + unsigned len, get_block_t gb) { return 0; } @@ -2538,6 +2539,12 @@ static inline int xip_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } #endif +/* PAGE_CACHE_ALIGN is defined in pagemap.h */ +#define xip_truncate_page(inode, from, get_block) \ + xip_zero_page_range(inode, from, PAGE_CACHE_ALIGN(from) - from, \ + get_block) + + #ifdef CONFIG_BLOCK typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode, loff_t file_offset); -- 1.8.4.rc3