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* [PATCH v6 0/9] fsdax: introduce fs query to support reflink
@ 2021-07-30  8:52 Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 1/9] pagemap: Introduce ->memory_failure() Shiyang Ruan
                   ` (8 more replies)
  0 siblings, 9 replies; 12+ messages in thread
From: Shiyang Ruan @ 2021-07-30  8:52 UTC (permalink / raw)
  To: linux-kernel, linux-xfs, nvdimm, linux-mm, linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

This patchset is aimed to support shared pages tracking for fsdax.

Change from V5:
  - fix dax_load_pfn(), take locked,empty,zero dax entry into
       consideration
  - fix the usage of rwsem lock for dax_device's holder
  - fix build error reported by kernelbot
  - keep functionality of dax_{,dis}assocaite_entry() for filesystems
       doesn't have rmapbt feature
  - Rebased to v5.14-rc3

This patchset moves owner tracking from dax_assocaite_entry() to pmem
device driver, by introducing an interface ->memory_failure() for struct
pagemap.  This interface is called by memory_failure() in mm, and
implemented by pmem device.

Then call holder operations to find the filesystem which the corrupted
data located in, and call filesystem handler to track files or metadata
associated with this page.

Finally we are able to try to fix the corrupted data in filesystem and
do other necessary processing, such as killing processes who are using
the files affected.

The call trace is like this:
memory_failure()
|* fsdax case
|------------
|pgmap->ops->memory_failure()      => pmem_pgmap_memory_failure()
| dax_holder_notify_failure()      =>
|  dax_device->holder_ops->notify_failure() =>
|                                     - xfs_dax_notify_failure()
|                                     - md_dax_notify_failure()
|  |* xfs_dax_notify_failure()
|  |--------------------------
|  |   xfs_rmap_query_range()
|  |    xfs_currupt_helper()
|  |    * corrupted on metadata
|  |       try to recover data, call xfs_force_shutdown()
|  |    * corrupted on file data
|  |       try to recover data, call mf_dax_kill_procs()
|  |* md_dax_notify_failure()
|  |-------------------------
|      md_targets->iterate_devices()
|      md_targets->rmap()          => linear_rmap()
|       dax_holder_notify_failure()
|* normal case
|-------------
 mf_generic_kill_procs()

The fsdax & reflink support for XFS is not contained in this patchset.

(Rebased on v5.14-rc3)
==

Shiyang Ruan (9):
  pagemap: Introduce ->memory_failure()
  dax: Introduce holder for dax_device
  mm: factor helpers for memory_failure_dev_pagemap
  pmem,mm: Implement ->memory_failure in pmem driver
  mm: Introduce mf_dax_kill_procs() for fsdax case
  xfs: Implement ->corrupted_range() for XFS
  dm: Introduce ->rmap() to find bdev offset
  md: Implement dax_holder_operations
  fsdax: add exception for reflinked files

 block/genhd.c                 |  56 +++++++++++
 drivers/dax/super.c           |  58 ++++++++++++
 drivers/md/dm-linear.c        |  20 ++++
 drivers/md/dm.c               | 126 ++++++++++++++++++++++++-
 drivers/nvdimm/pmem.c         |  13 +++
 fs/dax.c                      |  59 ++++++++----
 fs/xfs/xfs_fsops.c            |   5 +
 fs/xfs/xfs_mount.h            |   1 +
 fs/xfs/xfs_super.c            | 135 +++++++++++++++++++++++++++
 include/linux/dax.h           |  46 +++++++++
 include/linux/device-mapper.h |   5 +
 include/linux/genhd.h         |   1 +
 include/linux/memremap.h      |   9 ++
 include/linux/mm.h            |  10 ++
 mm/memory-failure.c           | 169 +++++++++++++++++++++++-----------
 15 files changed, 641 insertions(+), 72 deletions(-)

-- 
2.32.0





^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v6 1/9] pagemap: Introduce ->memory_failure()
  2021-07-30  8:52 [PATCH v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
@ 2021-07-30  8:52 ` Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 2/9] dax: Introduce holder for dax_device Shiyang Ruan
                   ` (7 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: Shiyang Ruan @ 2021-07-30  8:52 UTC (permalink / raw)
  To: linux-kernel, linux-xfs, nvdimm, linux-mm, linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

When memory-failure occurs, we call this function which is implemented
by each kind of devices.  For the fsdax case, pmem device driver
implements it.  Pmem device driver will find out the filesystem in which
the corrupted page located in.  And finally call filesystem handler to
deal with this error.

The filesystem will try to recover the corrupted data if necessary.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 include/linux/memremap.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index c0e9d35889e8..ed6980087db5 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -87,6 +87,15 @@ struct dev_pagemap_ops {
 	 * the page back to a CPU accessible page.
 	 */
 	vm_fault_t (*migrate_to_ram)(struct vm_fault *vmf);
+
+	/*
+	 * Handle the memory failure happens on a range of pfns.  Notify the
+	 * processes who are using these pfns, and try to recover the data on
+	 * them if necessary.  The flag is finally passed to the recover
+	 * function through the whole notify routine.
+	 */
+	int (*memory_failure)(struct dev_pagemap *pgmap, unsigned long pfn,
+			      unsigned long nr_pfns, int flags);
 };
 
 #define PGMAP_ALTMAP_VALID	(1 << 0)
-- 
2.32.0





^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v6 2/9] dax: Introduce holder for dax_device
  2021-07-30  8:52 [PATCH v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 1/9] pagemap: Introduce ->memory_failure() Shiyang Ruan
@ 2021-07-30  8:52 ` Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 3/9] mm: factor helpers for memory_failure_dev_pagemap Shiyang Ruan
                   ` (6 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: Shiyang Ruan @ 2021-07-30  8:52 UTC (permalink / raw)
  To: linux-kernel, linux-xfs, nvdimm, linux-mm, linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

To easily track filesystem from a pmem device, we introduce a holder for
dax_device structure, and also its operation.  This holder is used to
remember who is using this dax_device:
 - When it is the backend of a filesystem, the holder will be the
   superblock of this filesystem.
 - When this pmem device is one of the targets in a mapped device, the
   holder will be this mapped device.  In this case, the mapped device
   has its own dax_device and it will follow the first rule.  So that we
   can finally track to the filesystem we needed.

The holder and holder_ops will be set when filesystem is being mounted,
or an target device is being activated.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 drivers/dax/super.c | 46 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/dax.h | 17 +++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 5fa6ae9dbc8b..00c32dfa5665 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -214,6 +214,8 @@ enum dax_device_flags {
  * @cdev: optional character interface for "device dax"
  * @host: optional name for lookups where the device path is not available
  * @private: dax driver private data
+ * @holder_rwsem: prevent unregistration while holder_ops is in progress
+ * @holder_data: holder of a dax_device: could be filesystem or mapped device
  * @flags: state and boolean properties
  */
 struct dax_device {
@@ -222,8 +224,11 @@ struct dax_device {
 	struct cdev cdev;
 	const char *host;
 	void *private;
+	struct rw_semaphore holder_rwsem;
+	void *holder_data;
 	unsigned long flags;
 	const struct dax_operations *ops;
+	const struct dax_holder_operations *holder_ops;
 };
 
 static ssize_t write_cache_show(struct device *dev,
@@ -373,6 +378,25 @@ int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
 }
 EXPORT_SYMBOL_GPL(dax_zero_page_range);
 
+int dax_holder_notify_failure(struct dax_device *dax_dev, loff_t offset,
+			      size_t size, void *data)
+{
+	int rc;
+
+	if (!dax_dev)
+		return -ENXIO;
+
+	if (!dax_dev->holder_data)
+		return -EOPNOTSUPP;
+
+	down_read(&dax_dev->holder_rwsem);
+	rc = dax_dev->holder_ops->notify_failure(dax_dev, offset,
+							 size, data);
+	up_read(&dax_dev->holder_rwsem);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(dax_holder_notify_failure);
+
 #ifdef CONFIG_ARCH_HAS_PMEM_API
 void arch_wb_cache_pmem(void *addr, size_t size);
 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size)
@@ -603,6 +627,7 @@ struct dax_device *alloc_dax(void *private, const char *__host,
 	dax_add_host(dax_dev, host);
 	dax_dev->ops = ops;
 	dax_dev->private = private;
+	init_rwsem(&dax_dev->holder_rwsem);
 	if (flags & DAXDEV_F_SYNC)
 		set_dax_synchronous(dax_dev);
 
@@ -624,6 +649,27 @@ void put_dax(struct dax_device *dax_dev)
 }
 EXPORT_SYMBOL_GPL(put_dax);
 
+void dax_set_holder(struct dax_device *dax_dev, void *holder,
+		const struct dax_holder_operations *ops)
+{
+	if (!dax_dev)
+		return;
+	down_write(&dax_dev->holder_rwsem);
+	dax_dev->holder_data = holder;
+	dax_dev->holder_ops = ops;
+	up_write(&dax_dev->holder_rwsem);
+}
+EXPORT_SYMBOL_GPL(dax_set_holder);
+
+void *dax_get_holder(struct dax_device *dax_dev)
+{
+	if (!dax_dev)
+		return NULL;
+
+	return dax_dev->holder_data;
+}
+EXPORT_SYMBOL_GPL(dax_get_holder);
+
 /**
  * dax_get_by_host() - temporary lookup mechanism for filesystem-dax
  * @host: alternate name for the device registered by a dax driver
diff --git a/include/linux/dax.h b/include/linux/dax.h
index b52f084aa643..6f4b5c97ceb0 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -38,10 +38,17 @@ struct dax_operations {
 	int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
 };
 
+struct dax_holder_operations {
+	int (*notify_failure)(struct dax_device *, loff_t, size_t, void *);
+};
+
 extern struct attribute_group dax_attribute_group;
 
 #if IS_ENABLED(CONFIG_DAX)
 struct dax_device *dax_get_by_host(const char *host);
+void dax_set_holder(struct dax_device *dax_dev, void *holder,
+		const struct dax_holder_operations *ops);
+void *dax_get_holder(struct dax_device *dax_dev);
 struct dax_device *alloc_dax(void *private, const char *host,
 		const struct dax_operations *ops, unsigned long flags);
 void put_dax(struct dax_device *dax_dev);
@@ -77,6 +84,14 @@ static inline struct dax_device *dax_get_by_host(const char *host)
 {
 	return NULL;
 }
+static inline void dax_set_holder(struct dax_device *dax_dev, void *holder,
+		const struct dax_holder_operations *ops)
+{
+}
+static inline void *dax_get_holder(struct dax_device *dax_dev)
+{
+	return NULL;
+}
 static inline struct dax_device *alloc_dax(void *private, const char *host,
 		const struct dax_operations *ops, unsigned long flags)
 {
@@ -226,6 +241,8 @@ size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 		size_t bytes, struct iov_iter *i);
 int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
 			size_t nr_pages);
+int dax_holder_notify_failure(struct dax_device *dax_dev, loff_t offset,
+		size_t size, void *data);
 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
 
 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
-- 
2.32.0





^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v6 3/9] mm: factor helpers for memory_failure_dev_pagemap
  2021-07-30  8:52 [PATCH v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 1/9] pagemap: Introduce ->memory_failure() Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 2/9] dax: Introduce holder for dax_device Shiyang Ruan
@ 2021-07-30  8:52 ` Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 4/9] pmem,mm: Implement ->memory_failure in pmem driver Shiyang Ruan
                   ` (5 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: Shiyang Ruan @ 2021-07-30  8:52 UTC (permalink / raw)
  To: linux-kernel, linux-xfs, nvdimm, linux-mm, linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

memory_failure_dev_pagemap code is a bit complex before introduce RMAP
feature for fsdax.  So it is needed to factor some helper functions to
simplify these code.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 mm/memory-failure.c | 101 +++++++++++++++++++++++++-------------------
 1 file changed, 57 insertions(+), 44 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index eefd823deb67..3bdfcb45f66e 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1423,6 +1423,60 @@ static int try_to_split_thp_page(struct page *page, const char *msg)
 	return 0;
 }
 
+static void unmap_and_kill(struct list_head *to_kill, unsigned long pfn,
+		struct address_space *mapping, pgoff_t index, int flags)
+{
+	struct to_kill *tk;
+	unsigned long size = 0;
+
+	list_for_each_entry(tk, to_kill, nd)
+		if (tk->size_shift)
+			size = max(size, 1UL << tk->size_shift);
+	if (size) {
+		/*
+		 * Unmap the largest mapping to avoid breaking up device-dax
+		 * mappings which are constant size. The actual size of the
+		 * mapping being torn down is communicated in siginfo, see
+		 * kill_proc()
+		 */
+		loff_t start = (index << PAGE_SHIFT) & ~(size - 1);
+
+		unmap_mapping_range(mapping, start, size, 0);
+	}
+
+	kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags);
+}
+
+static int mf_generic_kill_procs(unsigned long long pfn, int flags)
+{
+	struct page *page = pfn_to_page(pfn);
+	LIST_HEAD(to_kill);
+	dax_entry_t cookie;
+
+	/*
+	 * Prevent the inode from being freed while we are interrogating
+	 * the address_space, typically this would be handled by
+	 * lock_page(), but dax pages do not use the page lock. This
+	 * also prevents changes to the mapping of this pfn until
+	 * poison signaling is complete.
+	 */
+	cookie = dax_lock_page(page);
+	if (!cookie)
+		return -EBUSY;
+	/*
+	 * Unlike System-RAM there is no possibility to swap in a
+	 * different physical page at a given virtual address, so all
+	 * userspace consumption of ZONE_DEVICE memory necessitates
+	 * SIGBUS (i.e. MF_MUST_KILL)
+	 */
+	flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
+	collect_procs(page, &to_kill, true);
+
+	unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags);
+	dax_unlock_page(page, cookie);
+	return 0;
+}
+
 static int memory_failure_hugetlb(unsigned long pfn, int flags)
 {
 	struct page *p = pfn_to_page(pfn);
@@ -1512,13 +1566,8 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
 		struct dev_pagemap *pgmap)
 {
 	struct page *page = pfn_to_page(pfn);
-	const bool unmap_success = true;
-	unsigned long size = 0;
-	struct to_kill *tk;
 	LIST_HEAD(tokill);
 	int rc = -EBUSY;
-	loff_t start;
-	dax_entry_t cookie;
 
 	if (flags & MF_COUNT_INCREASED)
 		/*
@@ -1532,20 +1581,9 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
 		goto out;
 	}
 
-	/*
-	 * Prevent the inode from being freed while we are interrogating
-	 * the address_space, typically this would be handled by
-	 * lock_page(), but dax pages do not use the page lock. This
-	 * also prevents changes to the mapping of this pfn until
-	 * poison signaling is complete.
-	 */
-	cookie = dax_lock_page(page);
-	if (!cookie)
-		goto out;
-
 	if (hwpoison_filter(page)) {
 		rc = 0;
-		goto unlock;
+		goto out;
 	}
 
 	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
@@ -1553,7 +1591,7 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
 		 * TODO: Handle HMM pages which may need coordination
 		 * with device-side memory.
 		 */
-		goto unlock;
+		goto out;
 	}
 
 	/*
@@ -1562,32 +1600,7 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
 	 */
 	SetPageHWPoison(page);
 
-	/*
-	 * Unlike System-RAM there is no possibility to swap in a
-	 * different physical page at a given virtual address, so all
-	 * userspace consumption of ZONE_DEVICE memory necessitates
-	 * SIGBUS (i.e. MF_MUST_KILL)
-	 */
-	flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
-	collect_procs(page, &tokill, flags & MF_ACTION_REQUIRED);
-
-	list_for_each_entry(tk, &tokill, nd)
-		if (tk->size_shift)
-			size = max(size, 1UL << tk->size_shift);
-	if (size) {
-		/*
-		 * Unmap the largest mapping to avoid breaking up
-		 * device-dax mappings which are constant size. The
-		 * actual size of the mapping being torn down is
-		 * communicated in siginfo, see kill_proc()
-		 */
-		start = (page->index << PAGE_SHIFT) & ~(size - 1);
-		unmap_mapping_range(page->mapping, start, size, 0);
-	}
-	kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
-	rc = 0;
-unlock:
-	dax_unlock_page(page, cookie);
+	mf_generic_kill_procs(pfn, flags);
 out:
 	/* drop pgmap ref acquired in caller */
 	put_dev_pagemap(pgmap);
-- 
2.32.0





^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v6 4/9] pmem,mm: Implement ->memory_failure in pmem driver
  2021-07-30  8:52 [PATCH v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
                   ` (2 preceding siblings ...)
  2021-07-30  8:52 ` [PATCH v6 3/9] mm: factor helpers for memory_failure_dev_pagemap Shiyang Ruan
@ 2021-07-30  8:52 ` Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 5/9] mm: Introduce mf_dax_kill_procs() for fsdax case Shiyang Ruan
                   ` (4 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: Shiyang Ruan @ 2021-07-30  8:52 UTC (permalink / raw)
  To: linux-kernel, linux-xfs, nvdimm, linux-mm, linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

With dax_holder notify support, we are able to notify the memory failure
from pmem driver to upper layers.  If there is something not support in
the notify routine, memory_failure will fall back to the generic hanlder.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 drivers/nvdimm/pmem.c | 13 +++++++++++++
 mm/memory-failure.c   | 14 ++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 1e0615b8565e..fea4ffc333b8 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -362,9 +362,22 @@ static void pmem_release_disk(void *__pmem)
 	del_gendisk(pmem->disk);
 }
 
+static int pmem_pagemap_memory_failure(struct dev_pagemap *pgmap,
+		unsigned long pfn, unsigned long nr_pfns, int flags)
+{
+	struct pmem_device *pmem =
+			container_of(pgmap, struct pmem_device, pgmap);
+	loff_t offset = PFN_PHYS(pfn) - pmem->phys_addr - pmem->data_offset;
+
+	return dax_holder_notify_failure(pmem->dax_dev, offset,
+					 page_size(pfn_to_page(pfn)) * nr_pfns,
+					 &flags);
+}
+
 static const struct dev_pagemap_ops fsdax_pagemap_ops = {
 	.kill			= pmem_pagemap_kill,
 	.cleanup		= pmem_pagemap_cleanup,
+	.memory_failure		= pmem_pagemap_memory_failure,
 };
 
 static int pmem_attach_disk(struct device *dev,
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 3bdfcb45f66e..ab3eda335acd 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1600,6 +1600,20 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
 	 */
 	SetPageHWPoison(page);
 
+	/*
+	 * Call driver's implementation to handle the memory failure, otherwise
+	 * fall back to generic handler.
+	 */
+	if (pgmap->ops->memory_failure) {
+		rc = pgmap->ops->memory_failure(pgmap, pfn, 1, flags);
+		/*
+		 * Fall back to generic handler too if operation is not
+		 * supported inside the driver/device/filesystem.
+		 */
+		if (rc != EOPNOTSUPP)
+			goto out;
+	}
+
 	mf_generic_kill_procs(pfn, flags);
 out:
 	/* drop pgmap ref acquired in caller */
-- 
2.32.0





^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v6 5/9] mm: Introduce mf_dax_kill_procs() for fsdax case
  2021-07-30  8:52 [PATCH v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
                   ` (3 preceding siblings ...)
  2021-07-30  8:52 ` [PATCH v6 4/9] pmem,mm: Implement ->memory_failure in pmem driver Shiyang Ruan
@ 2021-07-30  8:52 ` Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 6/9] xfs: Implement ->corrupted_range() for XFS Shiyang Ruan
                   ` (3 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: Shiyang Ruan @ 2021-07-30  8:52 UTC (permalink / raw)
  To: linux-kernel, linux-xfs, nvdimm, linux-mm, linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

This function is called at the end of RMAP routine, i.e. filesystem
recovery function.  The difference between mf_generic_kill_procs() is,
mf_dax_kill_procs() accepts file mapping and offset instead of struct
page.  It is because that different file mappings and offsets may share
the same page in fsdax mode.  So, it is called when filesystem RMAP
results are found.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 fs/dax.c            | 45 ++++++++++++++++++++++++-------
 include/linux/dax.h | 16 ++++++++++++
 include/linux/mm.h  | 10 +++++++
 mm/memory-failure.c | 64 +++++++++++++++++++++++++++++++++------------
 4 files changed, 109 insertions(+), 26 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index da41f9363568..dce6307a12eb 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -389,6 +389,41 @@ static struct page *dax_busy_page(void *entry)
 	return NULL;
 }
 
+/**
+ * dax_load_pfn - Load pfn of the DAX entry corresponding to a page
+ * @mapping:	The file whose entry we want to load
+ * @index:	offset where the DAX entry located in
+ *
+ * Return:	pfn number of the DAX entry
+ */
+unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index)
+{
+	XA_STATE(xas, &mapping->i_pages, index);
+	void *entry;
+	unsigned long pfn;
+
+	rcu_read_lock();
+	for (;;) {
+		xas_lock_irq(&xas);
+		entry = xas_load(&xas);
+		if (dax_is_locked(entry)) {
+			rcu_read_unlock();
+			wait_entry_unlocked(&xas, entry);
+			rcu_read_lock();
+			continue;
+		}
+
+		if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry))
+			pfn = 0;
+		else
+			pfn = dax_to_pfn(entry);
+		xas_unlock_irq(&xas);
+		break;
+	}
+	rcu_read_unlock();
+	return pfn;
+}
+
 /*
  * dax_lock_mapping_entry - Lock the DAX entry corresponding to a page
  * @page: The page whose entry we want to lock
@@ -790,16 +825,6 @@ static void *dax_insert_entry(struct xa_state *xas,
 	return entry;
 }
 
-static inline
-unsigned long pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma)
-{
-	unsigned long address;
-
-	address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
-	VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
-	return address;
-}
-
 /* Walk all mappings of a given index of a file and writeprotect them */
 static void dax_entry_mkclean(struct address_space *mapping, pgoff_t index,
 		unsigned long pfn)
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 6f4b5c97ceb0..359e809516b8 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -165,6 +165,7 @@ int dax_writeback_mapping_range(struct address_space *mapping,
 
 struct page *dax_layout_busy_page(struct address_space *mapping);
 struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
+unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index);
 dax_entry_t dax_lock_page(struct page *page);
 void dax_unlock_page(struct page *page, dax_entry_t cookie);
 #else
@@ -206,6 +207,12 @@ static inline int dax_writeback_mapping_range(struct address_space *mapping,
 	return -EOPNOTSUPP;
 }
 
+static inline unsigned long dax_load_pfn(struct address_space *mapping,
+		unsigned long index)
+{
+	return 0;
+}
+
 static inline dax_entry_t dax_lock_page(struct page *page)
 {
 	if (IS_DAX(page->mapping->host))
@@ -259,6 +266,15 @@ static inline bool dax_mapping(struct address_space *mapping)
 {
 	return mapping->host && IS_DAX(mapping->host);
 }
+static inline unsigned long pgoff_address(pgoff_t pgoff,
+		struct vm_area_struct *vma)
+{
+	unsigned long address;
+
+	address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+	VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
+	return address;
+}
 
 #ifdef CONFIG_DEV_DAX_HMEM_DEVICES
 void hmem_register_device(int target_nid, struct resource *r);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7ca22e6e694a..530aaf7a6eb2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1190,6 +1190,14 @@ static inline bool is_device_private_page(const struct page *page)
 		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
 }
 
+static inline bool is_device_fsdax_page(const struct page *page)
+{
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		IS_ENABLED(CONFIG_FS_DAX) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_FS_DAX;
+}
+
 static inline bool is_pci_p2pdma_page(const struct page *page)
 {
 	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
@@ -3113,6 +3121,8 @@ enum mf_flags {
 	MF_MUST_KILL = 1 << 2,
 	MF_SOFT_OFFLINE = 1 << 3,
 };
+extern int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index,
+			     int flags);
 extern int memory_failure(unsigned long pfn, int flags);
 extern void memory_failure_queue(unsigned long pfn, int flags);
 extern void memory_failure_queue_kick(int cpu);
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index ab3eda335acd..520664c405fc 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -134,6 +134,12 @@ static int hwpoison_filter_dev(struct page *p)
 	if (PageSlab(p))
 		return -EINVAL;
 
+	if (pfn_valid(page_to_pfn(p))) {
+		if (is_device_fsdax_page(p))
+			return 0;
+	} else
+		return -EINVAL;
+
 	mapping = page_mapping(p);
 	if (mapping == NULL || mapping->host == NULL)
 		return -EINVAL;
@@ -304,10 +310,9 @@ void shake_page(struct page *p, int access)
 }
 EXPORT_SYMBOL_GPL(shake_page);
 
-static unsigned long dev_pagemap_mapping_shift(struct page *page,
+static unsigned long dev_pagemap_mapping_shift(unsigned long address,
 		struct vm_area_struct *vma)
 {
-	unsigned long address = vma_address(page, vma);
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
@@ -347,7 +352,7 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page,
  * Schedule a process for later kill.
  * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM.
  */
-static void add_to_kill(struct task_struct *tsk, struct page *p,
+static void add_to_kill(struct task_struct *tsk, struct page *p, pgoff_t pgoff,
 		       struct vm_area_struct *vma,
 		       struct list_head *to_kill)
 {
@@ -360,9 +365,14 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
 	}
 
 	tk->addr = page_address_in_vma(p, vma);
-	if (is_zone_device_page(p))
-		tk->size_shift = dev_pagemap_mapping_shift(p, vma);
-	else
+	if (is_zone_device_page(p)) {
+		/* Since page->mapping is no more used for fsdax, we should
+		 * calculate the address in a fsdax way.
+		 */
+		if (is_device_fsdax_page(p))
+			tk->addr = pgoff_address(pgoff, vma);
+		tk->size_shift = dev_pagemap_mapping_shift(tk->addr, vma);
+	} else
 		tk->size_shift = page_shift(compound_head(p));
 
 	/*
@@ -510,7 +520,7 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
 			if (!page_mapped_in_vma(page, vma))
 				continue;
 			if (vma->vm_mm == t->mm)
-				add_to_kill(t, page, vma, to_kill);
+				add_to_kill(t, page, 0, vma, to_kill);
 		}
 	}
 	read_unlock(&tasklist_lock);
@@ -520,24 +530,20 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
 /*
  * Collect processes when the error hit a file mapped page.
  */
-static void collect_procs_file(struct page *page, struct list_head *to_kill,
-				int force_early)
+static void collect_procs_file(struct page *page, struct address_space *mapping,
+		pgoff_t pgoff, struct list_head *to_kill, int force_early)
 {
 	struct vm_area_struct *vma;
 	struct task_struct *tsk;
-	struct address_space *mapping = page->mapping;
-	pgoff_t pgoff;
 
 	i_mmap_lock_read(mapping);
 	read_lock(&tasklist_lock);
-	pgoff = page_to_pgoff(page);
 	for_each_process(tsk) {
 		struct task_struct *t = task_early_kill(tsk, force_early);
 
 		if (!t)
 			continue;
-		vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff,
-				      pgoff) {
+		vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
 			/*
 			 * Send early kill signal to tasks where a vma covers
 			 * the page but the corrupted page is not necessarily
@@ -546,7 +552,7 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
 			 * to be informed of all such data corruptions.
 			 */
 			if (vma->vm_mm == t->mm)
-				add_to_kill(t, page, vma, to_kill);
+				add_to_kill(t, page, pgoff, vma, to_kill);
 		}
 	}
 	read_unlock(&tasklist_lock);
@@ -565,7 +571,8 @@ static void collect_procs(struct page *page, struct list_head *tokill,
 	if (PageAnon(page))
 		collect_procs_anon(page, tokill, force_early);
 	else
-		collect_procs_file(page, tokill, force_early);
+		collect_procs_file(page, page->mapping, page->index, tokill,
+				   force_early);
 }
 
 struct hwp_walk {
@@ -1477,6 +1484,31 @@ static int mf_generic_kill_procs(unsigned long long pfn, int flags)
 	return 0;
 }
 
+int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, int flags)
+{
+	LIST_HEAD(to_kill);
+	/* load the pfn of the dax mapping file */
+	unsigned long pfn = dax_load_pfn(mapping, index);
+
+	/* the failure pfn may not actually be mmapped, so no need to
+	 * unmap and kill procs */
+	if (!pfn)
+		return 0;
+
+	/*
+	 * Unlike System-RAM there is no possibility to swap in a
+	 * different physical page at a given virtual address, so all
+	 * userspace consumption of ZONE_DEVICE memory necessitates
+	 * SIGBUS (i.e. MF_MUST_KILL)
+	 */
+	flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
+	collect_procs_file(pfn_to_page(pfn), mapping, index, &to_kill, true);
+
+	unmap_and_kill(&to_kill, pfn, mapping, index, flags);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mf_dax_kill_procs);
+
 static int memory_failure_hugetlb(unsigned long pfn, int flags)
 {
 	struct page *p = pfn_to_page(pfn);
-- 
2.32.0





^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v6 6/9] xfs: Implement ->corrupted_range() for XFS
  2021-07-30  8:52 [PATCH v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
                   ` (4 preceding siblings ...)
  2021-07-30  8:52 ` [PATCH v6 5/9] mm: Introduce mf_dax_kill_procs() for fsdax case Shiyang Ruan
@ 2021-07-30  8:52 ` Shiyang Ruan
  2021-07-30  9:15   ` David Hildenbrand
  2021-07-30  8:52 ` [PATCH v6 7/9] dm: Introduce ->rmap() to find bdev offset Shiyang Ruan
                   ` (2 subsequent siblings)
  8 siblings, 1 reply; 12+ messages in thread
From: Shiyang Ruan @ 2021-07-30  8:52 UTC (permalink / raw)
  To: linux-kernel, linux-xfs, nvdimm, linux-mm, linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

This function is used to handle errors which may cause data lost in
filesystem.  Such as memory failure in fsdax mode.

If the rmap feature of XFS enabled, we can query it to find files and
metadata which are associated with the corrupt data.  For now all we do
is kill processes with that file mapped into their address spaces, but
future patches could actually do something about corrupt metadata.

After that, the memory failure needs to notify the processes who are
using those files.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 drivers/dax/super.c |  12 ++++
 fs/xfs/xfs_fsops.c  |   5 ++
 fs/xfs/xfs_mount.h  |   1 +
 fs/xfs/xfs_super.c  | 135 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/dax.h |  13 +++++
 5 files changed, 166 insertions(+)

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 00c32dfa5665..63f7b63d078d 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -65,6 +65,18 @@ struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
 	return dax_get_by_host(bdev->bd_disk->disk_name);
 }
 EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
+
+void fs_dax_set_holder(struct dax_device *dax_dev, void *holder,
+		const struct dax_holder_operations *ops)
+{
+	dax_set_holder(dax_dev, holder, ops);
+}
+EXPORT_SYMBOL_GPL(fs_dax_set_holder);
+void *fs_dax_get_holder(struct dax_device *dax_dev)
+{
+	return dax_get_holder(dax_dev);
+}
+EXPORT_SYMBOL_GPL(fs_dax_get_holder);
 #endif
 
 bool __generic_fsdax_supported(struct dax_device *dax_dev,
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 6ed29b158312..e96ddb5c28bc 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -549,6 +549,11 @@ xfs_do_force_shutdown(
 				flags, __return_address, fname, lnnum);
 		if (XFS_ERRLEVEL_HIGH <= xfs_error_level)
 			xfs_stack_trace();
+	} else if (flags & SHUTDOWN_CORRUPT_META) {
+		xfs_alert_tag(mp, XFS_PTAG_SHUTDOWN_CORRUPT,
+"Corruption of on-disk metadata detected.  Shutting down filesystem");
+		if (XFS_ERRLEVEL_HIGH <= xfs_error_level)
+			xfs_stack_trace();
 	} else if (logerror) {
 		xfs_alert_tag(mp, XFS_PTAG_SHUTDOWN_LOGERROR,
 "Log I/O error (0x%x) detected at %pS (%s:%d). Shutting down filesystem",
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index c78b63fe779a..203eb62d16d0 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -277,6 +277,7 @@ void xfs_do_force_shutdown(struct xfs_mount *mp, int flags, char *fname,
 #define SHUTDOWN_LOG_IO_ERROR	0x0002	/* write attempt to the log failed */
 #define SHUTDOWN_FORCE_UMOUNT	0x0004	/* shutdown from a forced unmount */
 #define SHUTDOWN_CORRUPT_INCORE	0x0008	/* corrupt in-memory data structures */
+#define SHUTDOWN_CORRUPT_META	0x0010  /* corrupt metadata on device */
 
 /*
  * Flags for xfs_mountfs
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 2c9e26a44546..4a362e14318d 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -37,11 +37,19 @@
 #include "xfs_reflink.h"
 #include "xfs_pwork.h"
 #include "xfs_ag.h"
+#include "xfs_alloc.h"
+#include "xfs_rmap.h"
+#include "xfs_rmap_btree.h"
+#include "xfs_rtalloc.h"
+#include "xfs_bit.h"
 
 #include <linux/magic.h>
 #include <linux/fs_context.h>
 #include <linux/fs_parser.h>
+#include <linux/mm.h>
+#include <linux/dax.h>
 
+static const struct dax_holder_operations xfs_dax_holder_operations;
 static const struct super_operations xfs_super_operations;
 
 static struct kset *xfs_kset;		/* top-level xfs sysfs dir */
@@ -352,6 +360,7 @@ xfs_close_devices(
 
 		xfs_free_buftarg(mp->m_logdev_targp);
 		xfs_blkdev_put(logdev);
+		fs_dax_set_holder(dax_logdev, NULL, NULL);
 		fs_put_dax(dax_logdev);
 	}
 	if (mp->m_rtdev_targp) {
@@ -360,9 +369,11 @@ xfs_close_devices(
 
 		xfs_free_buftarg(mp->m_rtdev_targp);
 		xfs_blkdev_put(rtdev);
+		fs_dax_set_holder(dax_rtdev, NULL, NULL);
 		fs_put_dax(dax_rtdev);
 	}
 	xfs_free_buftarg(mp->m_ddev_targp);
+	fs_dax_set_holder(dax_ddev, NULL, NULL);
 	fs_put_dax(dax_ddev);
 }
 
@@ -386,6 +397,7 @@ xfs_open_devices(
 	struct block_device	*logdev = NULL, *rtdev = NULL;
 	int			error;
 
+	fs_dax_set_holder(dax_ddev, mp, &xfs_dax_holder_operations);
 	/*
 	 * Open real time and log devices - order is important.
 	 */
@@ -394,6 +406,9 @@ xfs_open_devices(
 		if (error)
 			goto out;
 		dax_logdev = fs_dax_get_by_bdev(logdev);
+		if (dax_logdev != dax_ddev)
+			fs_dax_set_holder(dax_logdev, mp,
+				       &xfs_dax_holder_operations);
 	}
 
 	if (mp->m_rtname) {
@@ -408,6 +423,7 @@ xfs_open_devices(
 			goto out_close_rtdev;
 		}
 		dax_rtdev = fs_dax_get_by_bdev(rtdev);
+		fs_dax_set_holder(dax_rtdev, mp, &xfs_dax_holder_operations);
 	}
 
 	/*
@@ -1070,6 +1086,125 @@ xfs_fs_free_cached_objects(
 	return xfs_reclaim_inodes_nr(XFS_M(sb), sc->nr_to_scan);
 }
 
+static int
+xfs_corrupt_helper(
+	struct xfs_btree_cur		*cur,
+	struct xfs_rmap_irec		*rec,
+	void				*data)
+{
+	struct xfs_inode		*ip;
+	struct address_space		*mapping;
+	int				error = 0, *flags = data, i;
+
+	if (XFS_RMAP_NON_INODE_OWNER(rec->rm_owner) ||
+	    (rec->rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK))) {
+		// TODO check and try to fix metadata
+		xfs_force_shutdown(cur->bc_mp, SHUTDOWN_CORRUPT_META);
+		return -EFSCORRUPTED;
+	}
+
+	/* Get files that incore, filter out others that are not in use. */
+	error = xfs_iget(cur->bc_mp, cur->bc_tp, rec->rm_owner, XFS_IGET_INCORE,
+			 0, &ip);
+	if (error)
+		return error;
+
+	mapping = VFS_I(ip)->i_mapping;
+	if (IS_ENABLED(CONFIG_MEMORY_FAILURE)) {
+		for (i = 0; i < rec->rm_blockcount; i++) {
+			error = mf_dax_kill_procs(mapping, rec->rm_offset + i,
+						  *flags);
+			if (error)
+				break;
+		}
+	}
+	// TODO try to fix data
+	xfs_irele(ip);
+
+	return error;
+}
+
+static loff_t
+xfs_dax_bdev_offset(
+	struct xfs_mount *mp,
+	struct dax_device *dax_dev,
+	loff_t disk_offset)
+{
+	struct block_device *bdev;
+
+	if (mp->m_ddev_targp->bt_daxdev == dax_dev)
+		bdev = mp->m_ddev_targp->bt_bdev;
+	else if (mp->m_logdev_targp->bt_daxdev == dax_dev)
+		bdev = mp->m_logdev_targp->bt_bdev;
+	else
+		bdev = mp->m_rtdev_targp->bt_bdev;
+
+	return disk_offset - (get_start_sect(bdev) << SECTOR_SHIFT);
+}
+
+static int
+xfs_dax_notify_failure(
+	struct dax_device	*dax_dev,
+	loff_t			offset,
+	size_t			len,
+	void			*data)
+{
+	struct xfs_mount	*mp = fs_dax_get_holder(dax_dev);
+	struct xfs_trans	*tp = NULL;
+	struct xfs_btree_cur	*cur = NULL;
+	struct xfs_buf		*agf_bp = NULL;
+	struct xfs_rmap_irec	rmap_low, rmap_high;
+	loff_t 			bdev_offset = xfs_dax_bdev_offset(mp, dax_dev,
+								  offset);
+	xfs_fsblock_t		fsbno = XFS_B_TO_FSB(mp, bdev_offset);
+	xfs_filblks_t		bcnt = XFS_B_TO_FSB(mp, len);
+	xfs_agnumber_t		agno = XFS_FSB_TO_AGNO(mp, fsbno);
+	xfs_agblock_t		agbno = XFS_FSB_TO_AGBNO(mp, fsbno);
+	int			error = 0;
+
+	if (mp->m_logdev_targp && mp->m_logdev_targp->bt_daxdev == dax_dev &&
+	    mp->m_logdev_targp != mp->m_ddev_targp) {
+		xfs_err(mp, "ondisk log corrupt, shutting down fs!");
+		xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_META);
+		return -EFSCORRUPTED;
+	}
+
+	if (!xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+		xfs_warn(mp, "notify_failure() needs rmapbt enabled!");
+		return -EOPNOTSUPP;
+	}
+
+	error = xfs_trans_alloc_empty(mp, &tp);
+	if (error)
+		return error;
+
+	error = xfs_alloc_read_agf(mp, tp, agno, 0, &agf_bp);
+	if (error)
+		goto out_cancel_tp;
+
+	cur = xfs_rmapbt_init_cursor(mp, tp, agf_bp, agf_bp->b_pag);
+
+	/* Construct a range for rmap query */
+	memset(&rmap_low, 0, sizeof(rmap_low));
+	memset(&rmap_high, 0xFF, sizeof(rmap_high));
+	rmap_low.rm_startblock = rmap_high.rm_startblock = agbno;
+	rmap_low.rm_blockcount = rmap_high.rm_blockcount = bcnt;
+
+	error = xfs_rmap_query_range(cur, &rmap_low, &rmap_high,
+				     xfs_corrupt_helper, data);
+
+	xfs_btree_del_cursor(cur, error);
+	xfs_trans_brelse(tp, agf_bp);
+
+out_cancel_tp:
+	xfs_trans_cancel(tp);
+	return error;
+}
+
+static const struct dax_holder_operations xfs_dax_holder_operations = {
+	.notify_failure = xfs_dax_notify_failure,
+};
+
 static const struct super_operations xfs_super_operations = {
 	.alloc_inode		= xfs_fs_alloc_inode,
 	.destroy_inode		= xfs_fs_destroy_inode,
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 359e809516b8..c8a188b76031 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -160,6 +160,9 @@ static inline void fs_put_dax(struct dax_device *dax_dev)
 }
 
 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
+void fs_dax_set_holder(struct dax_device *dax_dev, void *holder,
+		const struct dax_holder_operations *ops);
+void *fs_dax_get_holder(struct dax_device *dax_dev);
 int dax_writeback_mapping_range(struct address_space *mapping,
 		struct dax_device *dax_dev, struct writeback_control *wbc);
 
@@ -191,6 +194,16 @@ static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
 	return NULL;
 }
 
+static inline void fs_dax_set_holder(struct dax_device *dax_dev, void *holder,
+		const struct dax_holder_operations *ops)
+{
+}
+
+static inline void *fs_dax_get_holder(struct dax_device *dax_dev)
+{
+	return NULL;
+}
+
 static inline struct page *dax_layout_busy_page(struct address_space *mapping)
 {
 	return NULL;
-- 
2.32.0





^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v6 7/9] dm: Introduce ->rmap() to find bdev offset
  2021-07-30  8:52 [PATCH v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
                   ` (5 preceding siblings ...)
  2021-07-30  8:52 ` [PATCH v6 6/9] xfs: Implement ->corrupted_range() for XFS Shiyang Ruan
@ 2021-07-30  8:52 ` Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 8/9] md: Implement dax_holder_operations Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 9/9] fsdax: add exception for reflinked files Shiyang Ruan
  8 siblings, 0 replies; 12+ messages in thread
From: Shiyang Ruan @ 2021-07-30  8:52 UTC (permalink / raw)
  To: linux-kernel, linux-xfs, nvdimm, linux-mm, linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

Pmem device could be a target of mapped device.  In order to find out
the global location on a mapped device, we introduce this to translate
offset from target device to mapped device.

Currently, we implement it on linear target, which is easy to do the
translation.  Other targets will be supported in the future.  However,
some targets may not support it because of the non-linear mapping.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 block/genhd.c                 | 56 +++++++++++++++++++++++++++++++++++
 drivers/md/dm-linear.c        | 20 +++++++++++++
 include/linux/device-mapper.h |  5 ++++
 include/linux/genhd.h         |  1 +
 4 files changed, 82 insertions(+)

diff --git a/block/genhd.c b/block/genhd.c
index af4d2ab4a633..7a595da0cbec 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -669,6 +669,62 @@ void blk_request_module(dev_t devt)
 		request_module("block-major-%d", MAJOR(devt));
 }
 
+/*
+ * bdget_disk - do bdget() by gendisk and partition number
+ * @disk: gendisk of interest
+ * @partno: partition number
+ *
+ * Find partition @partno from @disk, do bdget() on it.
+ *
+ * CONTEXT:
+ * Don't care.
+ *
+ * RETURNS:
+ * Resulting block_device on success, NULL on failure.
+ */
+static inline struct block_device *bdget_disk(struct gendisk *disk, int partno)
+{
+	struct block_device *bdev = NULL;
+
+	rcu_read_lock();
+	bdev = xa_load(&disk->part_tbl, partno);
+	if (bdev && !bdgrab(bdev))
+		bdev = NULL;
+	rcu_read_unlock();
+
+	return bdev;
+}
+
+/**
+ * bdget_disk_sector - get block device by given sector number
+ * @disk: gendisk of interest
+ * @sector: sector number
+ *
+ * RETURNS: the found block device where sector locates in
+ */
+struct block_device *bdget_disk_sector(struct gendisk *disk, sector_t sector)
+{
+	struct block_device *part = NULL, *p;
+	unsigned long idx;
+
+	rcu_read_lock();
+	xa_for_each(&disk->part_tbl, idx, p) {
+		if (p->bd_partno == 0)
+			continue;
+		if (p->bd_start_sect <= sector &&
+			sector < p->bd_start_sect + bdev_nr_sectors(p)) {
+			part = p;
+			break;
+		}
+	}
+	rcu_read_unlock();
+	if (!part)
+		part = disk->part0;
+
+	return bdget_disk(disk, part->bd_partno);
+}
+EXPORT_SYMBOL(bdget_disk_sector);
+
 /*
  * print a full list of all partitions - intended for places where the root
  * filesystem can't be mounted and thus to give the victim some idea of what
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index c91f1e2e2f65..d28577bd358b 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -5,6 +5,7 @@
  */
 
 #include "dm.h"
+#include "dm-core.h"
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/blkdev.h>
@@ -119,6 +120,24 @@ static void linear_status(struct dm_target *ti, status_type_t type,
 	}
 }
 
+static int linear_rmap(struct dm_target *ti, sector_t offset,
+		       rmap_callout_fn fn, void *data)
+{
+	struct linear_c *lc = (struct linear_c *) ti->private;
+	struct mapped_device *md = ti->table->md;
+	struct block_device *bdev;
+	sector_t disk_sect = offset - dm_target_offset(ti, lc->start);
+	int rc = -ENODEV;
+
+	bdev = bdget_disk_sector(md->disk, offset);
+	if (!bdev)
+		return rc;
+
+	rc = fn(ti, bdev, disk_sect, data);
+	bdput(bdev);
+	return rc;
+}
+
 static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
 {
 	struct linear_c *lc = (struct linear_c *) ti->private;
@@ -235,6 +254,7 @@ static struct target_type linear_target = {
 	.ctr    = linear_ctr,
 	.dtr    = linear_dtr,
 	.map    = linear_map,
+	.rmap   = linear_rmap,
 	.status = linear_status,
 	.prepare_ioctl = linear_prepare_ioctl,
 	.iterate_devices = linear_iterate_devices,
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 7457d49acf9a..4069983c4618 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -58,6 +58,10 @@ typedef void (*dm_dtr_fn) (struct dm_target *ti);
  * = 2: The target wants to push back the io
  */
 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
+typedef int (*rmap_callout_fn) (struct dm_target *ti, struct block_device *bdev,
+				sector_t sect, void *data);
+typedef int (*dm_rmap_fn) (struct dm_target *ti, sector_t offset,
+			   rmap_callout_fn fn, void *data);
 typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
 					    struct request *rq,
 					    union map_info *map_context,
@@ -184,6 +188,7 @@ struct target_type {
 	dm_ctr_fn ctr;
 	dm_dtr_fn dtr;
 	dm_map_fn map;
+	dm_rmap_fn rmap;
 	dm_clone_and_map_request_fn clone_and_map_rq;
 	dm_release_clone_request_fn release_clone_rq;
 	dm_endio_fn end_io;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 13b34177cc85..7de6fdc14de6 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -223,6 +223,7 @@ static inline void add_disk_no_queue_reg(struct gendisk *disk)
 }
 
 extern void del_gendisk(struct gendisk *gp);
+extern struct block_device *bdget_disk_sector(struct gendisk *disk, sector_t sector);
 
 void set_disk_ro(struct gendisk *disk, bool read_only);
 
-- 
2.32.0





^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v6 8/9] md: Implement dax_holder_operations
  2021-07-30  8:52 [PATCH v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
                   ` (6 preceding siblings ...)
  2021-07-30  8:52 ` [PATCH v6 7/9] dm: Introduce ->rmap() to find bdev offset Shiyang Ruan
@ 2021-07-30  8:52 ` Shiyang Ruan
  2021-07-30  8:52 ` [PATCH v6 9/9] fsdax: add exception for reflinked files Shiyang Ruan
  8 siblings, 0 replies; 12+ messages in thread
From: Shiyang Ruan @ 2021-07-30  8:52 UTC (permalink / raw)
  To: linux-kernel, linux-xfs, nvdimm, linux-mm, linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

This is the case where the holder represents a mapped device, or a list
of mapped devices more exactly(because it is possible to create more
than one mapped device on one pmem device).

Find out which mapped device the offset belongs to, and translate the
offset from target device to mapped device.  When it is done, call
dax_corrupted_range() for the holder of this mapped device.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 drivers/md/dm.c | 126 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 125 insertions(+), 1 deletion(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 2c5f9e585211..a35b9a97a73f 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -626,7 +626,11 @@ static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
 }
 
 static char *_dm_claim_ptr = "I belong to device-mapper";
-
+static const struct dax_holder_operations dm_dax_holder_ops;
+struct dm_holder {
+	struct list_head list;
+	struct mapped_device *md;
+};
 /*
  * Open a table device so we can use it as a map destination.
  */
@@ -634,6 +638,8 @@ static int open_table_device(struct table_device *td, dev_t dev,
 			     struct mapped_device *md)
 {
 	struct block_device *bdev;
+	struct list_head *holders;
+	struct dm_holder *holder;
 
 	int r;
 
@@ -651,6 +657,19 @@ static int open_table_device(struct table_device *td, dev_t dev,
 
 	td->dm_dev.bdev = bdev;
 	td->dm_dev.dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
+	if (!td->dm_dev.dax_dev)
+		return 0;
+
+	holders = dax_get_holder(td->dm_dev.dax_dev);
+	if (!holders) {
+		holders = kmalloc(sizeof(*holders), GFP_KERNEL);
+		INIT_LIST_HEAD(holders);
+		dax_set_holder(td->dm_dev.dax_dev, holders, &dm_dax_holder_ops);
+	}
+	holder = kmalloc(sizeof(*holder), GFP_KERNEL);
+	holder->md = md;
+	list_add_tail(&holder->list, holders);
+
 	return 0;
 }
 
@@ -659,9 +678,27 @@ static int open_table_device(struct table_device *td, dev_t dev,
  */
 static void close_table_device(struct table_device *td, struct mapped_device *md)
 {
+	struct list_head *holders;
+	struct dm_holder *holder, *n;
+
 	if (!td->dm_dev.bdev)
 		return;
 
+	holders = dax_get_holder(td->dm_dev.dax_dev);
+	if (holders) {
+		list_for_each_entry_safe(holder, n, holders, list) {
+			if (holder->md == md) {
+				list_del(&holder->list);
+				kfree(holder);
+			}
+		}
+		if (list_empty(holders)) {
+			kfree(holders);
+			/* unset dax_device's holder_data */
+			dax_set_holder(td->dm_dev.dax_dev, NULL, NULL);
+		}
+	}
+
 	bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
 	blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
 	put_dax(td->dm_dev.dax_dev);
@@ -1115,6 +1152,89 @@ static int dm_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
 	return ret;
 }
 
+#if IS_ENABLED(CONFIG_DAX_DRIVER)
+struct corrupted_hit_info {
+	struct dax_device *dax_dev;
+	sector_t offset;
+};
+
+static int dm_blk_corrupted_hit(struct dm_target *ti, struct dm_dev *dev,
+				sector_t start, sector_t count, void *data)
+{
+	struct corrupted_hit_info *bc = data;
+
+	return bc->dax_dev == (void *)dev->dax_dev &&
+			(start <= bc->offset && bc->offset < start + count);
+}
+
+struct corrupted_do_info {
+	size_t length;
+	void *data;
+};
+
+static int dm_blk_corrupted_do(struct dm_target *ti, struct block_device *bdev,
+			       sector_t sector, void *data)
+{
+	struct mapped_device *md = ti->table->md;
+	struct corrupted_do_info *bc = data;
+
+	return dax_holder_notify_failure(md->dax_dev, to_bytes(sector),
+					 bc->length, bc->data);
+}
+
+static int dm_dax_notify_failure_one(struct mapped_device *md,
+				     struct dax_device *dax_dev,
+				     loff_t offset, size_t length, void *data)
+{
+	struct dm_table *map;
+	struct dm_target *ti;
+	sector_t sect = to_sector(offset);
+	struct corrupted_hit_info hi = {dax_dev, sect};
+	struct corrupted_do_info di = {length, data};
+	int srcu_idx, i, rc = -ENODEV;
+
+	map = dm_get_live_table(md, &srcu_idx);
+	if (!map)
+		return rc;
+
+	/*
+	 * find the target device, and then translate the offset of this target
+	 * to the whole mapped device.
+	 */
+	for (i = 0; i < dm_table_get_num_targets(map); i++) {
+		ti = dm_table_get_target(map, i);
+		if (!(ti->type->iterate_devices && ti->type->rmap))
+			continue;
+		if (!ti->type->iterate_devices(ti, dm_blk_corrupted_hit, &hi))
+			continue;
+
+		rc = ti->type->rmap(ti, sect, dm_blk_corrupted_do, &di);
+		break;
+	}
+
+	dm_put_live_table(md, srcu_idx);
+	return rc;
+}
+
+static int dm_dax_notify_failure(struct dax_device *dax_dev,
+				 loff_t offset, size_t length, void *data)
+{
+	struct dm_holder *holder;
+	struct list_head *holders = dax_get_holder(dax_dev);
+	int rc = -ENODEV;
+
+	list_for_each_entry(holder, holders, list) {
+		rc = dm_dax_notify_failure_one(holder->md, dax_dev, offset,
+					       length, data);
+		if (rc != -ENODEV)
+			break;
+	}
+	return rc;
+}
+#else
+#define dm_dax_notify_failure NULL
+#endif
+
 /*
  * A target may call dm_accept_partial_bio only from the map routine.  It is
  * allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_* zone management
@@ -3057,6 +3177,10 @@ static const struct dax_operations dm_dax_ops = {
 	.zero_page_range = dm_dax_zero_page_range,
 };
 
+static const struct dax_holder_operations dm_dax_holder_ops = {
+	.notify_failure = dm_dax_notify_failure,
+};
+
 /*
  * module hooks
  */
-- 
2.32.0





^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v6 9/9] fsdax: add exception for reflinked files
  2021-07-30  8:52 [PATCH v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
                   ` (7 preceding siblings ...)
  2021-07-30  8:52 ` [PATCH v6 8/9] md: Implement dax_holder_operations Shiyang Ruan
@ 2021-07-30  8:52 ` Shiyang Ruan
  8 siblings, 0 replies; 12+ messages in thread
From: Shiyang Ruan @ 2021-07-30  8:52 UTC (permalink / raw)
  To: linux-kernel, linux-xfs, nvdimm, linux-mm, linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

For reflinked files, one dax page may be associated more than once with
different fime mapping and index.  It will report warning.  Now, since
we have introduced dax-RMAP for this case and also have to keep its
functionality for other filesystems who are not support rmap, I add this
exception here.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 fs/dax.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index dce6307a12eb..f5910d178695 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -352,9 +352,10 @@ static void dax_associate_entry(void *entry, struct address_space *mapping,
 	for_each_mapped_pfn(entry, pfn) {
 		struct page *page = pfn_to_page(pfn);
 
-		WARN_ON_ONCE(page->mapping);
-		page->mapping = mapping;
-		page->index = index + i++;
+		if (!page->mapping) {
+			page->mapping = mapping;
+			page->index = index + i++;
+		}
 	}
 }
 
@@ -370,9 +371,10 @@ static void dax_disassociate_entry(void *entry, struct address_space *mapping,
 		struct page *page = pfn_to_page(pfn);
 
 		WARN_ON_ONCE(trunc && page_ref_count(page) > 1);
-		WARN_ON_ONCE(page->mapping && page->mapping != mapping);
-		page->mapping = NULL;
-		page->index = 0;
+		if (page->mapping == mapping) {
+			page->mapping = NULL;
+			page->index = 0;
+		}
 	}
 }
 
-- 
2.32.0





^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v6 6/9] xfs: Implement ->corrupted_range() for XFS
  2021-07-30  8:52 ` [PATCH v6 6/9] xfs: Implement ->corrupted_range() for XFS Shiyang Ruan
@ 2021-07-30  9:15   ` David Hildenbrand
  2021-07-30  9:25     ` ruansy.fnst
  0 siblings, 1 reply; 12+ messages in thread
From: David Hildenbrand @ 2021-07-30  9:15 UTC (permalink / raw)
  To: Shiyang Ruan, linux-kernel, linux-xfs, nvdimm, linux-mm,
	linux-fsdevel, dm-devel
  Cc: djwong, dan.j.williams, david, hch, agk, snitzer

There is no ocurrence of "corrupted_range" in this patch. Does the patch 
subject need updating?


On 30.07.21 10:52, Shiyang Ruan wrote:
> This function is used to handle errors which may cause data lost in
> filesystem.  Such as memory failure in fsdax mode.
> 
> If the rmap feature of XFS enabled, we can query it to find files and
> metadata which are associated with the corrupt data.  For now all we do
> is kill processes with that file mapped into their address spaces, but
> future patches could actually do something about corrupt metadata.
> 
> After that, the memory failure needs to notify the processes who are
> using those files.
> 
> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
> ---
>   drivers/dax/super.c |  12 ++++
>   fs/xfs/xfs_fsops.c  |   5 ++
>   fs/xfs/xfs_mount.h  |   1 +
>   fs/xfs/xfs_super.c  | 135 ++++++++++++++++++++++++++++++++++++++++++++
>   include/linux/dax.h |  13 +++++
>   5 files changed, 166 insertions(+)
> 
> diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> index 00c32dfa5665..63f7b63d078d 100644
> --- a/drivers/dax/super.c
> +++ b/drivers/dax/super.c
> @@ -65,6 +65,18 @@ struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
>   	return dax_get_by_host(bdev->bd_disk->disk_name);
>   }
>   EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
> +
> +void fs_dax_set_holder(struct dax_device *dax_dev, void *holder,
> +		const struct dax_holder_operations *ops)
> +{
> +	dax_set_holder(dax_dev, holder, ops);
> +}
> +EXPORT_SYMBOL_GPL(fs_dax_set_holder);
> +void *fs_dax_get_holder(struct dax_device *dax_dev)
> +{
> +	return dax_get_holder(dax_dev);
> +}
> +EXPORT_SYMBOL_GPL(fs_dax_get_holder);
>   #endif
>   
>   bool __generic_fsdax_supported(struct dax_device *dax_dev,
> diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
> index 6ed29b158312..e96ddb5c28bc 100644
> --- a/fs/xfs/xfs_fsops.c
> +++ b/fs/xfs/xfs_fsops.c
> @@ -549,6 +549,11 @@ xfs_do_force_shutdown(
>   				flags, __return_address, fname, lnnum);
>   		if (XFS_ERRLEVEL_HIGH <= xfs_error_level)
>   			xfs_stack_trace();
> +	} else if (flags & SHUTDOWN_CORRUPT_META) {
> +		xfs_alert_tag(mp, XFS_PTAG_SHUTDOWN_CORRUPT,
> +"Corruption of on-disk metadata detected.  Shutting down filesystem");
> +		if (XFS_ERRLEVEL_HIGH <= xfs_error_level)
> +			xfs_stack_trace();
>   	} else if (logerror) {
>   		xfs_alert_tag(mp, XFS_PTAG_SHUTDOWN_LOGERROR,
>   "Log I/O error (0x%x) detected at %pS (%s:%d). Shutting down filesystem",
> diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
> index c78b63fe779a..203eb62d16d0 100644
> --- a/fs/xfs/xfs_mount.h
> +++ b/fs/xfs/xfs_mount.h
> @@ -277,6 +277,7 @@ void xfs_do_force_shutdown(struct xfs_mount *mp, int flags, char *fname,
>   #define SHUTDOWN_LOG_IO_ERROR	0x0002	/* write attempt to the log failed */
>   #define SHUTDOWN_FORCE_UMOUNT	0x0004	/* shutdown from a forced unmount */
>   #define SHUTDOWN_CORRUPT_INCORE	0x0008	/* corrupt in-memory data structures */
> +#define SHUTDOWN_CORRUPT_META	0x0010  /* corrupt metadata on device */
>   
>   /*
>    * Flags for xfs_mountfs
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 2c9e26a44546..4a362e14318d 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -37,11 +37,19 @@
>   #include "xfs_reflink.h"
>   #include "xfs_pwork.h"
>   #include "xfs_ag.h"
> +#include "xfs_alloc.h"
> +#include "xfs_rmap.h"
> +#include "xfs_rmap_btree.h"
> +#include "xfs_rtalloc.h"
> +#include "xfs_bit.h"
>   
>   #include <linux/magic.h>
>   #include <linux/fs_context.h>
>   #include <linux/fs_parser.h>
> +#include <linux/mm.h>
> +#include <linux/dax.h>
>   
> +static const struct dax_holder_operations xfs_dax_holder_operations;
>   static const struct super_operations xfs_super_operations;
>   
>   static struct kset *xfs_kset;		/* top-level xfs sysfs dir */
> @@ -352,6 +360,7 @@ xfs_close_devices(
>   
>   		xfs_free_buftarg(mp->m_logdev_targp);
>   		xfs_blkdev_put(logdev);
> +		fs_dax_set_holder(dax_logdev, NULL, NULL);
>   		fs_put_dax(dax_logdev);
>   	}
>   	if (mp->m_rtdev_targp) {
> @@ -360,9 +369,11 @@ xfs_close_devices(
>   
>   		xfs_free_buftarg(mp->m_rtdev_targp);
>   		xfs_blkdev_put(rtdev);
> +		fs_dax_set_holder(dax_rtdev, NULL, NULL);
>   		fs_put_dax(dax_rtdev);
>   	}
>   	xfs_free_buftarg(mp->m_ddev_targp);
> +	fs_dax_set_holder(dax_ddev, NULL, NULL);
>   	fs_put_dax(dax_ddev);
>   }
>   
> @@ -386,6 +397,7 @@ xfs_open_devices(
>   	struct block_device	*logdev = NULL, *rtdev = NULL;
>   	int			error;
>   
> +	fs_dax_set_holder(dax_ddev, mp, &xfs_dax_holder_operations);
>   	/*
>   	 * Open real time and log devices - order is important.
>   	 */
> @@ -394,6 +406,9 @@ xfs_open_devices(
>   		if (error)
>   			goto out;
>   		dax_logdev = fs_dax_get_by_bdev(logdev);
> +		if (dax_logdev != dax_ddev)
> +			fs_dax_set_holder(dax_logdev, mp,
> +				       &xfs_dax_holder_operations);
>   	}
>   
>   	if (mp->m_rtname) {
> @@ -408,6 +423,7 @@ xfs_open_devices(
>   			goto out_close_rtdev;
>   		}
>   		dax_rtdev = fs_dax_get_by_bdev(rtdev);
> +		fs_dax_set_holder(dax_rtdev, mp, &xfs_dax_holder_operations);
>   	}
>   
>   	/*
> @@ -1070,6 +1086,125 @@ xfs_fs_free_cached_objects(
>   	return xfs_reclaim_inodes_nr(XFS_M(sb), sc->nr_to_scan);
>   }
>   
> +static int
> +xfs_corrupt_helper(
> +	struct xfs_btree_cur		*cur,
> +	struct xfs_rmap_irec		*rec,
> +	void				*data)
> +{
> +	struct xfs_inode		*ip;
> +	struct address_space		*mapping;
> +	int				error = 0, *flags = data, i;
> +
> +	if (XFS_RMAP_NON_INODE_OWNER(rec->rm_owner) ||
> +	    (rec->rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK))) {
> +		// TODO check and try to fix metadata
> +		xfs_force_shutdown(cur->bc_mp, SHUTDOWN_CORRUPT_META);
> +		return -EFSCORRUPTED;
> +	}
> +
> +	/* Get files that incore, filter out others that are not in use. */
> +	error = xfs_iget(cur->bc_mp, cur->bc_tp, rec->rm_owner, XFS_IGET_INCORE,
> +			 0, &ip);
> +	if (error)
> +		return error;
> +
> +	mapping = VFS_I(ip)->i_mapping;
> +	if (IS_ENABLED(CONFIG_MEMORY_FAILURE)) {
> +		for (i = 0; i < rec->rm_blockcount; i++) {
> +			error = mf_dax_kill_procs(mapping, rec->rm_offset + i,
> +						  *flags);
> +			if (error)
> +				break;
> +		}
> +	}
> +	// TODO try to fix data
> +	xfs_irele(ip);
> +
> +	return error;
> +}
> +
> +static loff_t
> +xfs_dax_bdev_offset(
> +	struct xfs_mount *mp,
> +	struct dax_device *dax_dev,
> +	loff_t disk_offset)
> +{
> +	struct block_device *bdev;
> +
> +	if (mp->m_ddev_targp->bt_daxdev == dax_dev)
> +		bdev = mp->m_ddev_targp->bt_bdev;
> +	else if (mp->m_logdev_targp->bt_daxdev == dax_dev)
> +		bdev = mp->m_logdev_targp->bt_bdev;
> +	else
> +		bdev = mp->m_rtdev_targp->bt_bdev;
> +
> +	return disk_offset - (get_start_sect(bdev) << SECTOR_SHIFT);
> +}
> +
> +static int
> +xfs_dax_notify_failure(
> +	struct dax_device	*dax_dev,
> +	loff_t			offset,
> +	size_t			len,
> +	void			*data)
> +{
> +	struct xfs_mount	*mp = fs_dax_get_holder(dax_dev);
> +	struct xfs_trans	*tp = NULL;
> +	struct xfs_btree_cur	*cur = NULL;
> +	struct xfs_buf		*agf_bp = NULL;
> +	struct xfs_rmap_irec	rmap_low, rmap_high;
> +	loff_t 			bdev_offset = xfs_dax_bdev_offset(mp, dax_dev,
> +								  offset);
> +	xfs_fsblock_t		fsbno = XFS_B_TO_FSB(mp, bdev_offset);
> +	xfs_filblks_t		bcnt = XFS_B_TO_FSB(mp, len);
> +	xfs_agnumber_t		agno = XFS_FSB_TO_AGNO(mp, fsbno);
> +	xfs_agblock_t		agbno = XFS_FSB_TO_AGBNO(mp, fsbno);
> +	int			error = 0;
> +
> +	if (mp->m_logdev_targp && mp->m_logdev_targp->bt_daxdev == dax_dev &&
> +	    mp->m_logdev_targp != mp->m_ddev_targp) {
> +		xfs_err(mp, "ondisk log corrupt, shutting down fs!");
> +		xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_META);
> +		return -EFSCORRUPTED;
> +	}
> +
> +	if (!xfs_sb_version_hasrmapbt(&mp->m_sb)) {
> +		xfs_warn(mp, "notify_failure() needs rmapbt enabled!");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	error = xfs_trans_alloc_empty(mp, &tp);
> +	if (error)
> +		return error;
> +
> +	error = xfs_alloc_read_agf(mp, tp, agno, 0, &agf_bp);
> +	if (error)
> +		goto out_cancel_tp;
> +
> +	cur = xfs_rmapbt_init_cursor(mp, tp, agf_bp, agf_bp->b_pag);
> +
> +	/* Construct a range for rmap query */
> +	memset(&rmap_low, 0, sizeof(rmap_low));
> +	memset(&rmap_high, 0xFF, sizeof(rmap_high));
> +	rmap_low.rm_startblock = rmap_high.rm_startblock = agbno;
> +	rmap_low.rm_blockcount = rmap_high.rm_blockcount = bcnt;
> +
> +	error = xfs_rmap_query_range(cur, &rmap_low, &rmap_high,
> +				     xfs_corrupt_helper, data);
> +
> +	xfs_btree_del_cursor(cur, error);
> +	xfs_trans_brelse(tp, agf_bp);
> +
> +out_cancel_tp:
> +	xfs_trans_cancel(tp);
> +	return error;
> +}
> +
> +static const struct dax_holder_operations xfs_dax_holder_operations = {
> +	.notify_failure = xfs_dax_notify_failure,
> +};
> +
>   static const struct super_operations xfs_super_operations = {
>   	.alloc_inode		= xfs_fs_alloc_inode,
>   	.destroy_inode		= xfs_fs_destroy_inode,
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index 359e809516b8..c8a188b76031 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -160,6 +160,9 @@ static inline void fs_put_dax(struct dax_device *dax_dev)
>   }
>   
>   struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
> +void fs_dax_set_holder(struct dax_device *dax_dev, void *holder,
> +		const struct dax_holder_operations *ops);
> +void *fs_dax_get_holder(struct dax_device *dax_dev);
>   int dax_writeback_mapping_range(struct address_space *mapping,
>   		struct dax_device *dax_dev, struct writeback_control *wbc);
>   
> @@ -191,6 +194,16 @@ static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
>   	return NULL;
>   }
>   
> +static inline void fs_dax_set_holder(struct dax_device *dax_dev, void *holder,
> +		const struct dax_holder_operations *ops)
> +{
> +}
> +
> +static inline void *fs_dax_get_holder(struct dax_device *dax_dev)
> +{
> +	return NULL;
> +}
> +
>   static inline struct page *dax_layout_busy_page(struct address_space *mapping)
>   {
>   	return NULL;
> 


-- 
Thanks,

David / dhildenb



^ permalink raw reply	[flat|nested] 12+ messages in thread

* RE: [PATCH v6 6/9] xfs: Implement ->corrupted_range() for XFS
  2021-07-30  9:15   ` David Hildenbrand
@ 2021-07-30  9:25     ` ruansy.fnst
  0 siblings, 0 replies; 12+ messages in thread
From: ruansy.fnst @ 2021-07-30  9:25 UTC (permalink / raw)
  To: David Hildenbrand, linux-kernel, linux-xfs, nvdimm, linux-mm,
	linux-fsdevel, dm-devel
  Cc: Darrick J. Wong, dan.j.williams, david, hch, agk, snitzer

> -----Original Message-----
> Subject: Re: [PATCH v6 6/9] xfs: Implement ->corrupted_range() for XFS
> 
> There is no ocurrence of "corrupted_range" in this patch. Does the patch
> subject need updating?
> 

Yes, I forgot this...  Thanks for pointing out.


--
Thanks,
Ruan.

> 
> On 30.07.21 10:52, Shiyang Ruan wrote:
> > This function is used to handle errors which may cause data lost in
> > filesystem.  Such as memory failure in fsdax mode.
> >
> > If the rmap feature of XFS enabled, we can query it to find files and
> > metadata which are associated with the corrupt data.  For now all we do
> > is kill processes with that file mapped into their address spaces, but
> > future patches could actually do something about corrupt metadata.
> >
> > After that, the memory failure needs to notify the processes who are
> > using those files.
> >
> > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
> > ---
> >   drivers/dax/super.c |  12 ++++
> >   fs/xfs/xfs_fsops.c  |   5 ++
> >   fs/xfs/xfs_mount.h  |   1 +
> >   fs/xfs/xfs_super.c  | 135
> ++++++++++++++++++++++++++++++++++++++++++++
> >   include/linux/dax.h |  13 +++++
> >   5 files changed, 166 insertions(+)
> >
> > diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> > index 00c32dfa5665..63f7b63d078d 100644
> > --- a/drivers/dax/super.c
> > +++ b/drivers/dax/super.c
> > @@ -65,6 +65,18 @@ struct dax_device *fs_dax_get_by_bdev(struct
> block_device *bdev)
> >   	return dax_get_by_host(bdev->bd_disk->disk_name);
> >   }
> >   EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
> > +
> > +void fs_dax_set_holder(struct dax_device *dax_dev, void *holder,
> > +		const struct dax_holder_operations *ops)
> > +{
> > +	dax_set_holder(dax_dev, holder, ops);
> > +}
> > +EXPORT_SYMBOL_GPL(fs_dax_set_holder);
> > +void *fs_dax_get_holder(struct dax_device *dax_dev)
> > +{
> > +	return dax_get_holder(dax_dev);
> > +}
> > +EXPORT_SYMBOL_GPL(fs_dax_get_holder);
> >   #endif
> >
> >   bool __generic_fsdax_supported(struct dax_device *dax_dev,
> > diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
> > index 6ed29b158312..e96ddb5c28bc 100644
> > --- a/fs/xfs/xfs_fsops.c
> > +++ b/fs/xfs/xfs_fsops.c
> > @@ -549,6 +549,11 @@ xfs_do_force_shutdown(
> >   				flags, __return_address, fname, lnnum);
> >   		if (XFS_ERRLEVEL_HIGH <= xfs_error_level)
> >   			xfs_stack_trace();
> > +	} else if (flags & SHUTDOWN_CORRUPT_META) {
> > +		xfs_alert_tag(mp, XFS_PTAG_SHUTDOWN_CORRUPT,
> > +"Corruption of on-disk metadata detected.  Shutting down filesystem");
> > +		if (XFS_ERRLEVEL_HIGH <= xfs_error_level)
> > +			xfs_stack_trace();
> >   	} else if (logerror) {
> >   		xfs_alert_tag(mp, XFS_PTAG_SHUTDOWN_LOGERROR,
> >   "Log I/O error (0x%x) detected at %pS (%s:%d). Shutting down filesystem",
> > diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
> > index c78b63fe779a..203eb62d16d0 100644
> > --- a/fs/xfs/xfs_mount.h
> > +++ b/fs/xfs/xfs_mount.h
> > @@ -277,6 +277,7 @@ void xfs_do_force_shutdown(struct xfs_mount *mp,
> int flags, char *fname,
> >   #define SHUTDOWN_LOG_IO_ERROR	0x0002	/* write attempt to the
> log failed */
> >   #define SHUTDOWN_FORCE_UMOUNT	0x0004	/* shutdown from
> a forced unmount */
> >   #define SHUTDOWN_CORRUPT_INCORE	0x0008	/* corrupt
> in-memory data structures */
> > +#define SHUTDOWN_CORRUPT_META	0x0010  /* corrupt metadata on
> device */
> >
> >   /*
> >    * Flags for xfs_mountfs
> > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> > index 2c9e26a44546..4a362e14318d 100644
> > --- a/fs/xfs/xfs_super.c
> > +++ b/fs/xfs/xfs_super.c
> > @@ -37,11 +37,19 @@
> >   #include "xfs_reflink.h"
> >   #include "xfs_pwork.h"
> >   #include "xfs_ag.h"
> > +#include "xfs_alloc.h"
> > +#include "xfs_rmap.h"
> > +#include "xfs_rmap_btree.h"
> > +#include "xfs_rtalloc.h"
> > +#include "xfs_bit.h"
> >
> >   #include <linux/magic.h>
> >   #include <linux/fs_context.h>
> >   #include <linux/fs_parser.h>
> > +#include <linux/mm.h>
> > +#include <linux/dax.h>
> >
> > +static const struct dax_holder_operations xfs_dax_holder_operations;
> >   static const struct super_operations xfs_super_operations;
> >
> >   static struct kset *xfs_kset;		/* top-level xfs sysfs dir */
> > @@ -352,6 +360,7 @@ xfs_close_devices(
> >
> >   		xfs_free_buftarg(mp->m_logdev_targp);
> >   		xfs_blkdev_put(logdev);
> > +		fs_dax_set_holder(dax_logdev, NULL, NULL);
> >   		fs_put_dax(dax_logdev);
> >   	}
> >   	if (mp->m_rtdev_targp) {
> > @@ -360,9 +369,11 @@ xfs_close_devices(
> >
> >   		xfs_free_buftarg(mp->m_rtdev_targp);
> >   		xfs_blkdev_put(rtdev);
> > +		fs_dax_set_holder(dax_rtdev, NULL, NULL);
> >   		fs_put_dax(dax_rtdev);
> >   	}
> >   	xfs_free_buftarg(mp->m_ddev_targp);
> > +	fs_dax_set_holder(dax_ddev, NULL, NULL);
> >   	fs_put_dax(dax_ddev);
> >   }
> >
> > @@ -386,6 +397,7 @@ xfs_open_devices(
> >   	struct block_device	*logdev = NULL, *rtdev = NULL;
> >   	int			error;
> >
> > +	fs_dax_set_holder(dax_ddev, mp, &xfs_dax_holder_operations);
> >   	/*
> >   	 * Open real time and log devices - order is important.
> >   	 */
> > @@ -394,6 +406,9 @@ xfs_open_devices(
> >   		if (error)
> >   			goto out;
> >   		dax_logdev = fs_dax_get_by_bdev(logdev);
> > +		if (dax_logdev != dax_ddev)
> > +			fs_dax_set_holder(dax_logdev, mp,
> > +				       &xfs_dax_holder_operations);
> >   	}
> >
> >   	if (mp->m_rtname) {
> > @@ -408,6 +423,7 @@ xfs_open_devices(
> >   			goto out_close_rtdev;
> >   		}
> >   		dax_rtdev = fs_dax_get_by_bdev(rtdev);
> > +		fs_dax_set_holder(dax_rtdev, mp, &xfs_dax_holder_operations);
> >   	}
> >
> >   	/*
> > @@ -1070,6 +1086,125 @@ xfs_fs_free_cached_objects(
> >   	return xfs_reclaim_inodes_nr(XFS_M(sb), sc->nr_to_scan);
> >   }
> >
> > +static int
> > +xfs_corrupt_helper(
> > +	struct xfs_btree_cur		*cur,
> > +	struct xfs_rmap_irec		*rec,
> > +	void				*data)
> > +{
> > +	struct xfs_inode		*ip;
> > +	struct address_space		*mapping;
> > +	int				error = 0, *flags = data, i;
> > +
> > +	if (XFS_RMAP_NON_INODE_OWNER(rec->rm_owner) ||
> > +	    (rec->rm_flags & (XFS_RMAP_ATTR_FORK |
> XFS_RMAP_BMBT_BLOCK))) {
> > +		// TODO check and try to fix metadata
> > +		xfs_force_shutdown(cur->bc_mp, SHUTDOWN_CORRUPT_META);
> > +		return -EFSCORRUPTED;
> > +	}
> > +
> > +	/* Get files that incore, filter out others that are not in use. */
> > +	error = xfs_iget(cur->bc_mp, cur->bc_tp, rec->rm_owner,
> XFS_IGET_INCORE,
> > +			 0, &ip);
> > +	if (error)
> > +		return error;
> > +
> > +	mapping = VFS_I(ip)->i_mapping;
> > +	if (IS_ENABLED(CONFIG_MEMORY_FAILURE)) {
> > +		for (i = 0; i < rec->rm_blockcount; i++) {
> > +			error = mf_dax_kill_procs(mapping, rec->rm_offset + i,
> > +						  *flags);
> > +			if (error)
> > +				break;
> > +		}
> > +	}
> > +	// TODO try to fix data
> > +	xfs_irele(ip);
> > +
> > +	return error;
> > +}
> > +
> > +static loff_t
> > +xfs_dax_bdev_offset(
> > +	struct xfs_mount *mp,
> > +	struct dax_device *dax_dev,
> > +	loff_t disk_offset)
> > +{
> > +	struct block_device *bdev;
> > +
> > +	if (mp->m_ddev_targp->bt_daxdev == dax_dev)
> > +		bdev = mp->m_ddev_targp->bt_bdev;
> > +	else if (mp->m_logdev_targp->bt_daxdev == dax_dev)
> > +		bdev = mp->m_logdev_targp->bt_bdev;
> > +	else
> > +		bdev = mp->m_rtdev_targp->bt_bdev;
> > +
> > +	return disk_offset - (get_start_sect(bdev) << SECTOR_SHIFT);
> > +}
> > +
> > +static int
> > +xfs_dax_notify_failure(
> > +	struct dax_device	*dax_dev,
> > +	loff_t			offset,
> > +	size_t			len,
> > +	void			*data)
> > +{
> > +	struct xfs_mount	*mp = fs_dax_get_holder(dax_dev);
> > +	struct xfs_trans	*tp = NULL;
> > +	struct xfs_btree_cur	*cur = NULL;
> > +	struct xfs_buf		*agf_bp = NULL;
> > +	struct xfs_rmap_irec	rmap_low, rmap_high;
> > +	loff_t 			bdev_offset = xfs_dax_bdev_offset(mp, dax_dev,
> > +								  offset);
> > +	xfs_fsblock_t		fsbno = XFS_B_TO_FSB(mp, bdev_offset);
> > +	xfs_filblks_t		bcnt = XFS_B_TO_FSB(mp, len);
> > +	xfs_agnumber_t		agno = XFS_FSB_TO_AGNO(mp, fsbno);
> > +	xfs_agblock_t		agbno = XFS_FSB_TO_AGBNO(mp, fsbno);
> > +	int			error = 0;
> > +
> > +	if (mp->m_logdev_targp && mp->m_logdev_targp->bt_daxdev ==
> dax_dev &&
> > +	    mp->m_logdev_targp != mp->m_ddev_targp) {
> > +		xfs_err(mp, "ondisk log corrupt, shutting down fs!");
> > +		xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_META);
> > +		return -EFSCORRUPTED;
> > +	}
> > +
> > +	if (!xfs_sb_version_hasrmapbt(&mp->m_sb)) {
> > +		xfs_warn(mp, "notify_failure() needs rmapbt enabled!");
> > +		return -EOPNOTSUPP;
> > +	}
> > +
> > +	error = xfs_trans_alloc_empty(mp, &tp);
> > +	if (error)
> > +		return error;
> > +
> > +	error = xfs_alloc_read_agf(mp, tp, agno, 0, &agf_bp);
> > +	if (error)
> > +		goto out_cancel_tp;
> > +
> > +	cur = xfs_rmapbt_init_cursor(mp, tp, agf_bp, agf_bp->b_pag);
> > +
> > +	/* Construct a range for rmap query */
> > +	memset(&rmap_low, 0, sizeof(rmap_low));
> > +	memset(&rmap_high, 0xFF, sizeof(rmap_high));
> > +	rmap_low.rm_startblock = rmap_high.rm_startblock = agbno;
> > +	rmap_low.rm_blockcount = rmap_high.rm_blockcount = bcnt;
> > +
> > +	error = xfs_rmap_query_range(cur, &rmap_low, &rmap_high,
> > +				     xfs_corrupt_helper, data);
> > +
> > +	xfs_btree_del_cursor(cur, error);
> > +	xfs_trans_brelse(tp, agf_bp);
> > +
> > +out_cancel_tp:
> > +	xfs_trans_cancel(tp);
> > +	return error;
> > +}
> > +
> > +static const struct dax_holder_operations xfs_dax_holder_operations = {
> > +	.notify_failure = xfs_dax_notify_failure,
> > +};
> > +
> >   static const struct super_operations xfs_super_operations = {
> >   	.alloc_inode		= xfs_fs_alloc_inode,
> >   	.destroy_inode		= xfs_fs_destroy_inode,
> > diff --git a/include/linux/dax.h b/include/linux/dax.h
> > index 359e809516b8..c8a188b76031 100644
> > --- a/include/linux/dax.h
> > +++ b/include/linux/dax.h
> > @@ -160,6 +160,9 @@ static inline void fs_put_dax(struct dax_device
> *dax_dev)
> >   }
> >
> >   struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
> > +void fs_dax_set_holder(struct dax_device *dax_dev, void *holder,
> > +		const struct dax_holder_operations *ops);
> > +void *fs_dax_get_holder(struct dax_device *dax_dev);
> >   int dax_writeback_mapping_range(struct address_space *mapping,
> >   		struct dax_device *dax_dev, struct writeback_control *wbc);
> >
> > @@ -191,6 +194,16 @@ static inline struct dax_device
> *fs_dax_get_by_bdev(struct block_device *bdev)
> >   	return NULL;
> >   }
> >
> > +static inline void fs_dax_set_holder(struct dax_device *dax_dev, void
> *holder,
> > +		const struct dax_holder_operations *ops)
> > +{
> > +}
> > +
> > +static inline void *fs_dax_get_holder(struct dax_device *dax_dev)
> > +{
> > +	return NULL;
> > +}
> > +
> >   static inline struct page *dax_layout_busy_page(struct address_space
> *mapping)
> >   {
> >   	return NULL;
> >
> 
> 
> --
> Thanks,
> 
> David / dhildenb


^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2021-07-30  9:25 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-30  8:52 [PATCH v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
2021-07-30  8:52 ` [PATCH v6 1/9] pagemap: Introduce ->memory_failure() Shiyang Ruan
2021-07-30  8:52 ` [PATCH v6 2/9] dax: Introduce holder for dax_device Shiyang Ruan
2021-07-30  8:52 ` [PATCH v6 3/9] mm: factor helpers for memory_failure_dev_pagemap Shiyang Ruan
2021-07-30  8:52 ` [PATCH v6 4/9] pmem,mm: Implement ->memory_failure in pmem driver Shiyang Ruan
2021-07-30  8:52 ` [PATCH v6 5/9] mm: Introduce mf_dax_kill_procs() for fsdax case Shiyang Ruan
2021-07-30  8:52 ` [PATCH v6 6/9] xfs: Implement ->corrupted_range() for XFS Shiyang Ruan
2021-07-30  9:15   ` David Hildenbrand
2021-07-30  9:25     ` ruansy.fnst
2021-07-30  8:52 ` [PATCH v6 7/9] dm: Introduce ->rmap() to find bdev offset Shiyang Ruan
2021-07-30  8:52 ` [PATCH v6 8/9] md: Implement dax_holder_operations Shiyang Ruan
2021-07-30  8:52 ` [PATCH v6 9/9] fsdax: add exception for reflinked files Shiyang Ruan

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