From: Shiyang Ruan <ruansy.fnst@cn.fujitsu.com>
To: <linux-kernel@vger.kernel.org>, <linux-xfs@vger.kernel.org>,
<linux-nvdimm@lists.01.org>, <linux-fsdevel@vger.kernel.org>
Cc: jack@suse.cz, darrick.wong@oracle.com, david@fromorbit.com,
ocfs2-devel@oss.oracle.com, viro@zeniv.linux.org.uk,
Goldwyn Rodrigues <rgoldwyn@suse.com>,
dan.j.williams@intel.com, linux-btrfs@vger.kernel.org
Subject: [Ocfs2-devel] [PATCH 2/7] fsdax: Introduce dax_copy_edges() for CoW
Date: Mon, 8 Feb 2021 01:09:19 +0800 [thread overview]
Message-ID: <20210207170924.2933035-3-ruansy.fnst@cn.fujitsu.com> (raw)
In-Reply-To: <20210207170924.2933035-1-ruansy.fnst@cn.fujitsu.com>
dax_copy_edges() is a helper functions performs a copy from one part of
the device to another for data not page aligned.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Shiyang Ruan <ruansy.fnst@cn.fujitsu.com>
---
fs/dax.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/fs/dax.c b/fs/dax.c
index b012b2db7ba2..ea4e8a434900 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1038,6 +1038,47 @@ static int dax_iomap_direct_access(struct iomap *iomap, loff_t pos, size_t size,
return rc;
}
+/*
+ * Copies the part of the pages not included in the write, but required for CoW
+ * because offset/offset+length are not page aligned.
+ */
+static int dax_copy_edges(loff_t pos, loff_t length, struct iomap *srcmap,
+ void *daddr, bool pmd)
+{
+ size_t page_size = pmd ? PMD_SIZE : PAGE_SIZE;
+ loff_t offset = pos & (page_size - 1);
+ size_t size = ALIGN(offset + length, page_size);
+ loff_t end = pos + length;
+ loff_t pg_end = round_up(end, page_size);
+ void *saddr = 0;
+ int ret = 0;
+
+ ret = dax_iomap_direct_access(srcmap, pos, size, &saddr, NULL);
+ if (ret)
+ return ret;
+ /*
+ * Copy the first part of the page
+ * Note: we pass offset as length
+ */
+ if (offset) {
+ if (saddr)
+ ret = copy_mc_to_kernel(daddr, saddr, offset);
+ else
+ memset(daddr, 0, offset);
+ }
+
+ /* Copy the last part of the range */
+ if (end < pg_end) {
+ if (saddr)
+ ret = copy_mc_to_kernel(daddr + offset + length,
+ saddr + offset + length, pg_end - end);
+ else
+ memset(daddr + offset + length, 0, pg_end - end);
+ }
+
+ return ret;
+}
+
/*
* The user has performed a load from a hole in the file. Allocating a new
* page in the file would cause excessive storage usage for workloads with
--
2.30.0
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next prev parent reply other threads:[~2021-02-08 16:54 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-07 17:09 [Ocfs2-devel] [PATCH 0/7] fsdax, xfs: Add reflink&dedupe support for fsdax Shiyang Ruan
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 1/7] fsdax: Output address in dax_iomap_pfn() and rename it Shiyang Ruan
2021-02-08 15:11 ` Christoph Hellwig
2021-02-22 7:44 ` Xiaoguang Wang
2021-02-23 1:32 ` [Ocfs2-devel] 回复: " ruansy.fnst
2021-02-07 17:09 ` Shiyang Ruan [this message]
2021-02-08 15:11 ` [Ocfs2-devel] [PATCH 2/7] fsdax: Introduce dax_copy_edges() for CoW Christoph Hellwig
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 3/7] fsdax: Copy data before write Shiyang Ruan
2021-02-08 15:14 ` Christoph Hellwig
2021-02-09 1:53 ` Ruan Shiyang
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 4/7] fsdax: Replace mmap entry in case of CoW Shiyang Ruan
2021-02-08 15:16 ` Christoph Hellwig
2021-02-16 13:11 ` David Sterba
2021-02-17 3:06 ` Ruan Shiyang
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 5/7] fsdax: Dedup file range to use a compare function Shiyang Ruan
2021-02-08 15:19 ` Christoph Hellwig
2021-02-09 9:15 ` Ruan Shiyang
2021-02-09 9:34 ` Christoph Hellwig
2021-02-09 9:46 ` Ruan Shiyang
2021-02-10 13:19 ` Christoph Hellwig
2021-02-17 3:24 ` Ruan Shiyang
2021-02-18 16:20 ` Darrick J. Wong
2021-02-25 7:35 ` Christoph Hellwig
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 6/7] fs/xfs: Handle CoW for fsdax write() path Shiyang Ruan
2021-02-08 15:24 ` Christoph Hellwig
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 7/7] fs/xfs: Add dedupe support for fsdax Shiyang Ruan
2021-02-08 15:39 ` [Ocfs2-devel] [PATCH 0/7] fsdax, xfs: Add reflink&dedupe " Jan Kara
2021-02-09 1:50 ` Ruan Shiyang
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