From: Shiyang Ruan <ruansy.fnst@fujitsu.com>
To: <linux-kernel@vger.kernel.org>, <linux-xfs@vger.kernel.org>,
<linux-nvdimm@lists.01.org>, <linux-fsdevel@vger.kernel.org>
Cc: <darrick.wong@oracle.com>, <dan.j.williams@intel.com>,
<willy@infradead.org>, <jack@suse.cz>, <viro@zeniv.linux.org.uk>,
<linux-btrfs@vger.kernel.org>, <ocfs2-devel@oss.oracle.com>,
<david@fromorbit.com>, <hch@lst.de>, <rgoldwyn@suse.de>,
Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH v2 05/10] fsdax: Replace mmap entry in case of CoW
Date: Fri, 26 Feb 2021 08:20:25 +0800 [thread overview]
Message-ID: <20210226002030.653855-6-ruansy.fnst@fujitsu.com> (raw)
In-Reply-To: <20210226002030.653855-1-ruansy.fnst@fujitsu.com>
We replace the existing entry to the newly allocated one in case of CoW.
Also, we mark the entry as PAGECACHE_TAG_TOWRITE so writeback marks this
entry as writeprotected. This helps us snapshots so new write
pagefaults after snapshots trigger a CoW.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
fs/dax.c | 37 ++++++++++++++++++++++++++-----------
1 file changed, 26 insertions(+), 11 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 748dfb89fb41..ec4b733e0b59 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -722,6 +722,9 @@ static int copy_cow_page_dax(struct block_device *bdev, struct dax_device *dax_d
return 0;
}
+#define DAX_IF_DIRTY (1 << 0)
+#define DAX_IF_COW (1 << 1)
+
/*
* By this point grab_mapping_entry() has ensured that we have a locked entry
* of the appropriate size so we don't have to worry about downgrading PMDs to
@@ -729,16 +732,19 @@ static int copy_cow_page_dax(struct block_device *bdev, struct dax_device *dax_d
* already in the tree, we will skip the insertion and just dirty the PMD as
* appropriate.
*/
-static void *dax_insert_entry(struct xa_state *xas,
- struct address_space *mapping, struct vm_fault *vmf,
- void *entry, pfn_t pfn, unsigned long flags, bool dirty)
+static void *dax_insert_entry(struct xa_state *xas, struct vm_fault *vmf,
+ void *entry, pfn_t pfn, unsigned long flags,
+ unsigned int insert_flags)
{
+ struct address_space *mapping = vmf->vma->vm_file->f_mapping;
void *new_entry = dax_make_entry(pfn, flags);
+ bool dirty = insert_flags & DAX_IF_DIRTY;
+ bool cow = insert_flags & DAX_IF_COW;
if (dirty)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
- if (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE)) {
+ if (cow || (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE))) {
unsigned long index = xas->xa_index;
/* we are replacing a zero page with block mapping */
if (dax_is_pmd_entry(entry))
@@ -750,7 +756,7 @@ static void *dax_insert_entry(struct xa_state *xas,
xas_reset(xas);
xas_lock_irq(xas);
- if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
+ if (cow || dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
void *old;
dax_disassociate_entry(entry, mapping, false);
@@ -774,6 +780,9 @@ static void *dax_insert_entry(struct xa_state *xas,
if (dirty)
xas_set_mark(xas, PAGECACHE_TAG_DIRTY);
+ if (cow)
+ xas_set_mark(xas, PAGECACHE_TAG_TOWRITE);
+
xas_unlock_irq(xas);
return entry;
}
@@ -1100,8 +1109,7 @@ static vm_fault_t dax_load_hole(struct xa_state *xas,
pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr));
vm_fault_t ret;
- *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn,
- DAX_ZERO_PAGE, false);
+ *entry = dax_insert_entry(xas, vmf, *entry, pfn, DAX_ZERO_PAGE, 0);
ret = vmf_insert_mixed(vmf->vma, vaddr, pfn);
trace_dax_load_hole(inode, vmf, ret);
@@ -1403,6 +1411,7 @@ static vm_fault_t dax_fault_actor(struct vm_fault *vmf, pfn_t *pfnp,
loff_t pos = (loff_t)xas->xa_offset << PAGE_SHIFT;
bool write = vmf->flags & FAULT_FLAG_WRITE;
bool sync = dax_fault_is_synchronous(flags, vmf->vma, iomap);
+ unsigned int insert_flags = 0;
vm_fault_t ret = 0;
int err = 0;
pfn_t pfn;
@@ -1426,8 +1435,14 @@ static vm_fault_t dax_fault_actor(struct vm_fault *vmf, pfn_t *pfnp,
if (err)
goto error_fault;
- entry = dax_insert_entry(xas, mapping, vmf, entry, pfn, 0,
- write && !sync);
+ if (write) {
+ if (!sync)
+ insert_flags |= DAX_IF_DIRTY;
+ if (iomap->flags & IOMAP_F_SHARED)
+ insert_flags |= DAX_IF_COW;
+ }
+
+ entry = dax_insert_entry(xas, vmf, entry, pfn, 0, insert_flags);
if (write && srcmap->addr != iomap->addr) {
err = dax_iomap_cow_copy(pos, size, size, srcmap, kaddr, false);
@@ -1571,8 +1586,8 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
goto fallback;
pfn = page_to_pfn_t(zero_page);
- *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn,
- DAX_PMD | DAX_ZERO_PAGE, false);
+ *entry = dax_insert_entry(xas, vmf, *entry, pfn,
+ DAX_PMD | DAX_ZERO_PAGE, 0);
if (arch_needs_pgtable_deposit()) {
pgtable = pte_alloc_one(vma->vm_mm);
--
2.30.1
next prev parent reply other threads:[~2021-02-26 0:25 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 0:20 [PATCH v2 00/10] fsdax,xfs: Add reflink&dedupe support for fsdax Shiyang Ruan
2021-02-26 0:20 ` [PATCH v2 01/10] fsdax: Factor helpers to simplify dax fault code Shiyang Ruan
2021-03-03 9:13 ` Christoph Hellwig
2021-02-26 0:20 ` [PATCH v2 02/10] fsdax: Factor helper: dax_fault_actor() Shiyang Ruan
2021-03-03 9:28 ` Christoph Hellwig
2021-03-12 9:01 ` ruansy.fnst
2021-02-26 0:20 ` [PATCH v2 03/10] fsdax: Output address in dax_iomap_pfn() and rename it Shiyang Ruan
2021-02-26 0:20 ` [PATCH v2 04/10] fsdax: Introduce dax_iomap_cow_copy() Shiyang Ruan
2021-03-03 9:29 ` Christoph Hellwig
2021-02-26 0:20 ` Shiyang Ruan [this message]
2021-03-03 9:30 ` [PATCH v2 05/10] fsdax: Replace mmap entry in case of CoW Christoph Hellwig
2021-03-03 9:41 ` ruansy.fnst
2021-03-03 9:44 ` Christoph Hellwig
2021-03-03 9:48 ` Christoph Hellwig
2021-02-26 0:20 ` [PATCH v2 06/10] fsdax: Add dax_iomap_cow_copy() for dax_iomap_zero Shiyang Ruan
2021-03-03 9:31 ` Christoph Hellwig
2021-02-26 0:20 ` [PATCH v2 07/10] iomap: Introduce iomap_apply2() for operations on two files Shiyang Ruan
2021-02-26 4:14 ` Darrick J. Wong
2021-02-26 8:11 ` ruansy.fnst
2021-02-26 8:25 ` Shiyang Ruan
2021-03-04 5:41 ` [RESEND PATCH v2.1 " Shiyang Ruan
2021-03-11 12:30 ` Christoph Hellwig
2021-02-26 0:20 ` [PATCH v2 08/10] fsdax: Dedup file range to use a compare function Shiyang Ruan
2021-02-26 8:28 ` Shiyang Ruan
2021-03-03 8:20 ` Joe Perches
2021-03-04 5:42 ` [RESEND PATCH v2.1 " Shiyang Ruan
2021-02-26 0:20 ` [PATCH v2 09/10] fs/xfs: Handle CoW for fsdax write() path Shiyang Ruan
2021-03-03 9:43 ` Christoph Hellwig
2021-03-03 9:57 ` ruansy.fnst
2021-03-03 10:43 ` Christoph Hellwig
2021-03-04 1:35 ` ruansy.fnst
2021-02-26 0:20 ` [PATCH v2 10/10] fs/xfs: Add dedupe support for fsdax Shiyang Ruan
2021-02-26 9:45 ` Question about the "EXPERIMENTAL" tag for dax in XFS ruansy.fnst
2021-02-26 19:04 ` Darrick J. Wong
2021-02-26 19:24 ` Dan Williams
2021-02-26 20:51 ` Dave Chinner
2021-02-26 20:59 ` Dan Williams
2021-02-26 21:27 ` Dave Chinner
2021-02-26 22:41 ` Dan Williams
2021-02-27 22:36 ` Dave Chinner
2021-02-27 23:40 ` Dan Williams
2021-02-28 22:38 ` Dave Chinner
2021-03-01 20:55 ` Dan Williams
2021-03-01 22:46 ` Dave Chinner
2021-03-02 0:32 ` Dan Williams
2021-03-02 2:42 ` Dave Chinner
2021-03-02 3:33 ` Dan Williams
2021-03-02 5:38 ` Dave Chinner
2021-03-02 5:50 ` Dan Williams
2021-03-02 3:28 ` Darrick J. Wong
2021-03-02 5:41 ` Dan Williams
2021-03-02 7:57 ` Dave Chinner
2021-03-02 17:49 ` Dan Williams
2021-03-04 23:40 ` Darrick J. Wong
2021-03-01 7:26 ` Yasunori Goto
2021-03-01 21:34 ` Dan Williams
2021-03-09 6:36 ` [PATCH v2 00/10] fsdax,xfs: Add reflink&dedupe support for fsdax Xiaoguang Wang
2021-03-09 16:19 ` Goldwyn Rodrigues
2021-03-10 1:26 ` ruansy.fnst
2021-03-10 12:30 ` Neal Gompa
2021-03-10 13:02 ` Matthew Wilcox
2021-03-10 13:36 ` Neal Gompa
2021-03-10 13:55 ` Matthew Wilcox
2021-03-10 14:21 ` Goldwyn Rodrigues
2021-03-10 14:26 ` Matthew Wilcox
2021-03-10 17:04 ` Goldwyn Rodrigues
2021-03-11 0:53 ` Dan Williams
2021-03-11 8:26 ` Neal Gompa
2021-03-13 13:07 ` Adam Borowski
2021-03-13 16:24 ` Neal Gompa
2021-03-13 22:00 ` Adam Borowski
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