From: Shiyang Ruan <ruansy.fnst@cn.fujitsu.com>
To: <linux-xfs@vger.kernel.org>, <linux-nvdimm@lists.01.org>,
<darrick.wong@oracle.com>, <rgoldwyn@suse.de>,
<hch@infradead.org>, <david@fromorbit.com>
Cc: <linux-kernel@vger.kernel.org>, <gujx@cn.fujitsu.com>,
<qi.fuli@fujitsu.com>, <caoj.fnst@cn.fujitsu.com>,
<ruansy.fnst@cn.fujitsu.com>,
Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [RFC PATCH v2 1/7] dax: Introduce dax_copy_edges() for COW.
Date: Wed, 30 Oct 2019 12:13:52 +0800 [thread overview]
Message-ID: <20191030041358.14450-2-ruansy.fnst@cn.fujitsu.com> (raw)
In-Reply-To: <20191030041358.14450-1-ruansy.fnst@cn.fujitsu.com>
To copy source data to destance address before write. Change
dax_iomap_pfn() to return the address as well in order to use it for
performing a memcpy in case the type is IOMAP_COW.
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 | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 58 insertions(+), 6 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 68eef98cd9c4..e1f4493ce56a 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -987,8 +987,8 @@ static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos)
return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9;
}
-static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size,
- pfn_t *pfnp)
+static int dax_iomap_direct_access(struct iomap *iomap, loff_t pos, size_t size,
+ pfn_t *pfnp, void **addr)
{
const sector_t sector = dax_iomap_sector(iomap, pos);
pgoff_t pgoff;
@@ -999,12 +999,14 @@ static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size,
if (rc)
return rc;
id = dax_read_lock();
- length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size),
- NULL, pfnp);
+ length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size), addr,
+ pfnp);
if (length < 0) {
rc = length;
goto out;
}
+ if (!pfnp)
+ goto out_check_addr;
rc = -EINVAL;
if (PFN_PHYS(length) < size)
goto out;
@@ -1014,6 +1016,12 @@ static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size,
if (length > 1 && !pfn_t_devmap(*pfnp))
goto out;
rc = 0;
+
+out_check_addr:
+ if (!addr)
+ goto out;
+ if (!*addr)
+ rc = -EFAULT;
out:
dax_read_unlock(id);
return rc;
@@ -1056,6 +1064,48 @@ static bool dax_range_is_aligned(struct block_device *bdev,
return true;
}
+/*
+ * dax_copy_edges - 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, NULL, &saddr);
+ if (ret)
+ return ret;
+ /*
+ * Copy the first part of the page
+ * Note: we pass offset as length
+ */
+ if (offset) {
+ if (saddr)
+ ret = memcpy_mcsafe(daddr, saddr, offset);
+ else
+ memset(daddr, 0, offset);
+ }
+
+ /* Copy the last part of the range */
+ if (end < pg_end) {
+ if (saddr)
+ ret = memcpy_mcsafe(daddr + offset + length,
+ saddr + offset + length, pg_end - end);
+ else
+ memset(daddr + offset + length, 0,
+ pg_end - end);
+ }
+ return ret;
+}
+
int __dax_zero_page_range(struct block_device *bdev,
struct dax_device *dax_dev, sector_t sector,
unsigned int offset, unsigned int size)
@@ -1342,7 +1392,8 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
count_memcg_event_mm(vma->vm_mm, PGMAJFAULT);
major = VM_FAULT_MAJOR;
}
- error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn);
+ error = dax_iomap_direct_access(&iomap, pos, PAGE_SIZE, &pfn,
+ NULL);
if (error < 0)
goto error_finish_iomap;
@@ -1560,7 +1611,8 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
switch (iomap.type) {
case IOMAP_MAPPED:
- error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn);
+ error = dax_iomap_direct_access(&iomap, pos, PMD_SIZE, &pfn,
+ NULL);
if (error < 0)
goto finish_iomap;
--
2.23.0
next prev parent reply other threads:[~2019-10-30 4:14 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-30 4:13 [RFC PATCH v2 0/7] xfs: reflink & dedupe for fsdax (read/write path) Shiyang Ruan
2019-10-30 4:13 ` Shiyang Ruan [this message]
2019-10-30 4:13 ` [RFC PATCH v2 2/7] dax: copy data before write Shiyang Ruan
2019-10-30 4:13 ` [RFC PATCH v2 3/7] dax: replace mmap entry in case of CoW Shiyang Ruan
2019-10-30 4:13 ` [RFC PATCH v2 4/7] fs: dedup file range to use a compare function Shiyang Ruan
2019-10-30 4:13 ` [RFC PATCH v2 5/7] dax: memcpy before zeroing range Shiyang Ruan
2019-10-30 4:13 ` [RFC PATCH v2 6/7] xfs: handle copy-on-write in fsdax write() path Shiyang Ruan
2019-10-30 4:13 ` [RFC PATCH v2 7/7] xfs: support dedupe for fsdax Shiyang Ruan
2019-10-30 11:48 ` [RFC PATCH v2 0/7] xfs: reflink & dedupe for fsdax (read/write path) Goldwyn Rodrigues
2019-10-31 4:54 ` Shiyang Ruan
2019-11-08 3:10 ` Shiyang Ruan
2019-11-08 3:30 ` Dan Williams
2019-11-14 20:24 ` Dave Chinner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191030041358.14450-2-ruansy.fnst@cn.fujitsu.com \
--to=ruansy.fnst@cn.fujitsu.com \
--cc=caoj.fnst@cn.fujitsu.com \
--cc=darrick.wong@oracle.com \
--cc=david@fromorbit.com \
--cc=gujx@cn.fujitsu.com \
--cc=hch@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nvdimm@lists.01.org \
--cc=linux-xfs@vger.kernel.org \
--cc=qi.fuli@fujitsu.com \
--cc=rgoldwyn@suse.com \
--cc=rgoldwyn@suse.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).