From patchwork Thu Sep 5 15:06:37 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Goldwyn Rodrigues X-Patchwork-Id: 11133313 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 02B4F924 for ; Thu, 5 Sep 2019 15:07:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 415A62082C for ; Thu, 5 Sep 2019 15:07:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390258AbfIEPHC (ORCPT ); Thu, 5 Sep 2019 11:07:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:55962 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2390251AbfIEPHB (ORCPT ); Thu, 5 Sep 2019 11:07:01 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 06792B114; Thu, 5 Sep 2019 15:06:59 +0000 (UTC) From: Goldwyn Rodrigues To: linux-fsdevel@vger.kernel.org Cc: linux-btrfs@vger.kernel.org, darrick.wong@oracle.com, hch@lst.de, linux-xfs@vger.kernel.org, Goldwyn Rodrigues Subject: [PATCH 02/15] iomap: Read page from srcmap if IOMAP_F_COW is set Date: Thu, 5 Sep 2019 10:06:37 -0500 Message-Id: <20190905150650.21089-3-rgoldwyn@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20190905150650.21089-1-rgoldwyn@suse.de> References: <20190905150650.21089-1-rgoldwyn@suse.de> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: Goldwyn Rodrigues In case of a IOMAP_F_COW, read a page from the srcmap before performing a write on the page. Signed-off-by: Goldwyn Rodrigues Reviewed-by: Darrick J. Wong --- fs/iomap/buffered-io.c | 30 +++++++++++++++++++++--------- include/linux/iomap.h | 3 +++ 2 files changed, 24 insertions(+), 9 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index f27756c0b31c..560459df75e4 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -581,7 +581,7 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, static int iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, - struct page **pagep, struct iomap *iomap) + struct page **pagep, struct iomap *iomap, struct iomap *srcmap) { const struct iomap_page_ops *page_ops = iomap->page_ops; pgoff_t index = pos >> PAGE_SHIFT; @@ -605,12 +605,24 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, goto out_no_page; } - if (iomap->type == IOMAP_INLINE) + if (iomap->type == IOMAP_INLINE) { iomap_read_inline_data(inode, page, iomap); - else if (iomap->flags & IOMAP_F_BUFFER_HEAD) + } else if (iomap->flags & IOMAP_F_COW) { + if (WARN_ON_ONCE(iomap->flags & IOMAP_F_BUFFER_HEAD)) { + status = -EIO; + goto out_no_page; + } + if (WARN_ON_ONCE(srcmap->type == IOMAP_HOLE && + srcmap->addr != IOMAP_NULL_ADDR)) { + status = -EIO; + goto out_no_page; + } + status = __iomap_write_begin(inode, pos, len, page, srcmap); + } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) { status = __block_write_begin_int(page, pos, len, NULL, iomap); - else + } else { status = __iomap_write_begin(inode, pos, len, page, iomap); + } if (unlikely(status)) goto out_unlock; @@ -772,7 +784,7 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, } status = iomap_write_begin(inode, pos, bytes, flags, &page, - iomap); + iomap, srcmap); if (unlikely(status)) break; @@ -871,7 +883,7 @@ iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data, return PTR_ERR(rpage); status = iomap_write_begin(inode, pos, bytes, - AOP_FLAG_NOFS, &page, iomap); + AOP_FLAG_NOFS, &page, iomap, srcmap); put_page(rpage); if (unlikely(status)) return status; @@ -917,13 +929,13 @@ iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len, EXPORT_SYMBOL_GPL(iomap_file_dirty); static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, - unsigned bytes, struct iomap *iomap) + unsigned bytes, struct iomap *iomap, struct iomap *srcmap) { struct page *page; int status; status = iomap_write_begin(inode, pos, bytes, AOP_FLAG_NOFS, &page, - iomap); + iomap, srcmap); if (status) return status; @@ -961,7 +973,7 @@ iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, if (IS_DAX(inode)) status = iomap_dax_zero(pos, offset, bytes, iomap); else - status = iomap_zero(inode, pos, offset, bytes, iomap); + status = iomap_zero(inode, pos, offset, bytes, iomap, srcmap); if (status < 0) return status; diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 9782a79dde59..7fdb09925740 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -44,6 +44,9 @@ struct vm_fault; #define IOMAP_F_MERGED 0x10 /* contains multiple blocks/extents */ #define IOMAP_F_SHARED 0x20 /* block shared with another file */ +/* Flags for CoW */ +#define IOMAP_F_COW 0x100 /* copy from srcmap before write */ + /* * Flags from 0x1000 up are for file system specific usage: */