linux.git/drivers/dax, branch v5.9-rc2

Merge tag 'libnvdimm-for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2020-08-11T17:59:19+00:00

Pull libnvdimm updayes from Vishal Verma:
 "You'd normally receive this pull request from Dan Williams, but he's
  busy watching a newborn (Congrats Dan!), so I'm watching libnvdimm
  this cycle.

  This adds a new feature in libnvdimm - 'Runtime Firmware Activation',
  and a few small cleanups and fixes in libnvdimm and DAX. I'd
  originally intended to make separate topic-based pull requests - one
  for libnvdimm, and one for DAX, but some of the DAX material fell out
  since it wasn't quite ready.

  Summary:

   - add 'Runtime Firmware Activation' support for NVDIMMs that
     advertise the relevant capability

   - misc libnvdimm and DAX cleanups"

* tag 'libnvdimm-for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm/security: ensure sysfs poll thread woke up and fetch updated attr
  libnvdimm/security: the 'security' attr never show 'overwrite' state
  libnvdimm/security: fix a typo
  ACPI: NFIT: Fix ARS zero-sized allocation
  dax: Fix incorrect argument passed to xas_set_err()
  ACPI: NFIT: Add runtime firmware activate support
  PM, libnvdimm: Add runtime firmware activation support
  libnvdimm: Convert to DEVICE_ATTR_ADMIN_RO()
  drivers/dax: Expand lock scope to cover the use of addresses
  fs/dax: Remove unused size parameter
  dax: print error message by pr_info() in __generic_fsdax_supported()
  driver-core: Introduce DEVICE_ATTR_ADMIN_{RO,RW}
  tools/testing/nvdimm: Emulate firmware activation commands
  tools/testing/nvdimm: Prepare nfit_ctl_test() for ND_CMD_CALL emulation
  tools/testing/nvdimm: Add command debug messages
  tools/testing/nvdimm: Cleanup dimm index passing
  ACPI: NFIT: Define runtime firmware activation commands
  ACPI: NFIT: Move bus_dsm_mask out of generic nvdimm_bus_descriptor
  libnvdimm: Validate command family indices

drivers/dax: Expand lock scope to cover the use of addresses

2020-07-28T17:50:08+00:00

The addition of PKS protection to dax read lock/unlock will require that
the address returned by dax_direct_access() be protected by this lock.

Correct the locking by ensuring that the use of kaddr and end_kaddr
are covered by the dax read lock/unlock.

Link: https://lore.kernel.org/r/20200717072056.73134-12-ira.weiny@intel.com
Reviewed-by: Dan Williams 
Signed-off-by: Ira Weiny 
Signed-off-by: Vishal Verma

dax: print error message by pr_info() in __generic_fsdax_supported()

2020-07-28T17:49:27+00:00

In struct dax_operations, the callback routine dax_supported() returns
a bool type result. For false return value, the caller has no idea
whether the device does not support dax at all, or it is just some mis-
configuration issue.

An example is formatting an Ext4 file system on pmem device on top of
a NVDIMM namespace by,
 # mkfs.ext4 /dev/pmem0
If the fs block size does not match kernel space memory page size (which
is possible on non-x86 platform), mount this Ext4 file system will fail,
  # mount -o dax /dev/pmem0 /mnt
  mount: /mnt: wrong fs type, bad option, bad superblock on /dev/pmem0,
  missing codepage or helper program, or other error.
And from the dmesg output there is only the following information,
  [  307.853148] EXT4-fs (pmem0): DAX unsupported by block device.

The above information is quite confusing. Because definitely the pmem0
device supports dax operation, and the super block is consistent as how
it was created by mkfs.ext4.

Indeed the failure is from __generic_fsdax_supported() by the following
code piece,
        if (blocksize != PAGE_SIZE) {
               pr_debug("%s: error: unsupported blocksize for dax\n",
                                bdevname(bdev, buf));
                return false;
        }
It is because the Ext4 block size is 4KB and kernel page size is 8KB or
16KB.

It is not simple to make dax_supported() from struct dax_operations
or __generic_fsdax_supported() to return exact failure type right now.
So the simplest fix is to use pr_info() to print all the error messages
inside __generic_fsdax_supported(). Then users may find informative clue
from the kernel message at least.

Message printed by pr_debug() is very easy to be ignored by users. This
patch prints error message by pr_info() in __generic_fsdax_supported(),
when then mount fails, following lines can be found from dmesg output,
 [ 2705.500885] pmem0: error: unsupported blocksize for dax
 [ 2705.500888] EXT4-fs (pmem0): DAX unsupported by block device.
Now the users may have idea the mount failure is from pmem driver for
unsupported block size.

Link: https://lore.kernel.org/r/20200725162450.95999-1-colyli@suse.de
Cc: Dan Williams 
Cc: Anthony Iliopoulos 
Reported-by: Michal Suchanek 
Suggested-by: Jan Kara 
Reviewed-by: Jan Kara 
Reviewed-by: Ira Weiny 
Reviewed-by: Pankaj Gupta 
Signed-off-by: Coly Li 
Signed-off-by: Vishal Verma

block: remove the bd_queue field from struct block_device

2020-07-01T14:08:20+00:00

Just use bd_disk->queue instead.

Reviewed-by: Johannes Thumshirn 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

device-dax: add memory via add_memory_driver_managed()

2020-06-05T02:06:23+00:00

Currently, when adding memory, we create entries in /sys/firmware/memmap/
as "System RAM".  This will lead to kexec-tools to add that memory to the
fixed-up initial memmap for a kexec kernel (loaded via kexec_load()).  The
memory will be considered initial System RAM by the kexec'd kernel and can
no longer be reconfigured.  This is not what happens during a real reboot.

Let's add our memory via add_memory_driver_managed() now, so we won't
create entries in /sys/firmware/memmap/ and indicate the memory as "System
RAM (kmem)" in /proc/iomem.  This allows everybody (especially
kexec-tools) to identify that this memory is special and has to be treated
differently than ordinary (hotplugged) System RAM.

Before configuring the namespace:
	[root@localhost ~]# cat /proc/iomem
	...
	140000000-33fffffff : Persistent Memory
	  140000000-33fffffff : namespace0.0
	3280000000-32ffffffff : PCI Bus 0000:00

After configuring the namespace:
	[root@localhost ~]# cat /proc/iomem
	...
	140000000-33fffffff : Persistent Memory
	  140000000-1481fffff : namespace0.0
	  148200000-33fffffff : dax0.0
	3280000000-32ffffffff : PCI Bus 0000:00

After loading kmem before this change:
	[root@localhost ~]# cat /proc/iomem
	...
	140000000-33fffffff : Persistent Memory
	  140000000-1481fffff : namespace0.0
	  150000000-33fffffff : dax0.0
	    150000000-33fffffff : System RAM
	3280000000-32ffffffff : PCI Bus 0000:00

After loading kmem after this change:
	[root@localhost ~]# cat /proc/iomem
	...
	140000000-33fffffff : Persistent Memory
	  140000000-1481fffff : namespace0.0
	  150000000-33fffffff : dax0.0
	    150000000-33fffffff : System RAM (kmem)
	3280000000-32ffffffff : PCI Bus 0000:00

After a proper reboot:
	[root@localhost ~]# cat /proc/iomem
	...
	140000000-33fffffff : Persistent Memory
	  140000000-1481fffff : namespace0.0
	  148200000-33fffffff : dax0.0
	3280000000-32ffffffff : PCI Bus 0000:00

Within the kexec kernel before this change:
	[root@localhost ~]# cat /proc/iomem
	...
	140000000-33fffffff : Persistent Memory
	  140000000-1481fffff : namespace0.0
	  150000000-33fffffff : System RAM
	3280000000-32ffffffff : PCI Bus 0000:00

Within the kexec kernel after this change:
	[root@localhost ~]# cat /proc/iomem
	...
	140000000-33fffffff : Persistent Memory
	  140000000-1481fffff : namespace0.0
	  148200000-33fffffff : dax0.0
	3280000000-32ffffffff : PCI Bus 0000:00

/sys/firmware/memmap/ before this change:
	0000000000000000-000000000009fc00 (System RAM)
	000000000009fc00-00000000000a0000 (Reserved)
	00000000000f0000-0000000000100000 (Reserved)
	0000000000100000-00000000bffdf000 (System RAM)
	00000000bffdf000-00000000c0000000 (Reserved)
	00000000feffc000-00000000ff000000 (Reserved)
	00000000fffc0000-0000000100000000 (Reserved)
	0000000100000000-0000000140000000 (System RAM)
	0000000150000000-0000000340000000 (System RAM)

/sys/firmware/memmap/ after a proper reboot:
	0000000000000000-000000000009fc00 (System RAM)
	000000000009fc00-00000000000a0000 (Reserved)
	00000000000f0000-0000000000100000 (Reserved)
	0000000000100000-00000000bffdf000 (System RAM)
	00000000bffdf000-00000000c0000000 (Reserved)
	00000000feffc000-00000000ff000000 (Reserved)
	00000000fffc0000-0000000100000000 (Reserved)
	0000000100000000-0000000140000000 (System RAM)

/sys/firmware/memmap/ after this change:
	0000000000000000-000000000009fc00 (System RAM)
	000000000009fc00-00000000000a0000 (Reserved)
	00000000000f0000-0000000000100000 (Reserved)
	0000000000100000-00000000bffdf000 (System RAM)
	00000000bffdf000-00000000c0000000 (Reserved)
	00000000feffc000-00000000ff000000 (Reserved)
	00000000fffc0000-0000000100000000 (Reserved)
	0000000100000000-0000000140000000 (System RAM)

kexec-tools already seem to basically ignore any System RAM that's not on
top level when searching for areas to place kexec images - but also for
determining crash areas to dump via kdump.  Changing the resource name
won't have an impact.

Handle unloading of the driver after memory hotremove failed properly, by
duplicating the string if necessary.

Signed-off-by: David Hildenbrand 
Signed-off-by: Andrew Morton 
Acked-by: Pankaj Gupta 
Cc: Michal Hocko 
Cc: Pankaj Gupta 
Cc: Wei Yang 
Cc: Baoquan He 
Cc: Dave Hansen 
Cc: Eric Biederman 
Cc: Pavel Tatashin 
Cc: Dan Williams 
Link: http://lkml.kernel.org/r/20200508084217.9160-5-david@redhat.com
Signed-off-by: Linus Torvalds

vfs: track per-sb writeback errors and report them to syncfs

2020-06-02T17:59:05+00:00

Patch series "vfs: have syncfs() return error when there are writeback
errors", v6.

Currently, syncfs does not return errors when one of the inodes fails to
be written back.  It will return errors based on the legacy AS_EIO and
AS_ENOSPC flags when syncing out the block device fails, but that's not
particularly helpful for filesystems that aren't backed by a blockdev.
It's also possible for a stray sync to lose those errors.

The basic idea in this set is to track writeback errors at the
superblock level, so that we can quickly and easily check whether
something bad happened without having to fsync each file individually.
syncfs is then changed to reliably report writeback errors after they
occur, much in the same fashion as fsync does now.

This patch (of 2):

Usually we suggest that applications call fsync when they want to ensure
that all data written to the file has made it to the backing store, but
that can be inefficient when there are a lot of open files.

Calling syncfs on the filesystem can be more efficient in some
situations, but the error reporting doesn't currently work the way most
people expect.  If a single inode on a filesystem reports a writeback
error, syncfs won't necessarily return an error.  syncfs only returns an
error if __sync_blockdev fails, and on some filesystems that's a no-op.

It would be better if syncfs reported an error if there were any
writeback failures.  Then applications could call syncfs to see if there
are any errors on any open files, and could then call fsync on all of
the other descriptors to figure out which one failed.

This patch adds a new errseq_t to struct super_block, and has
mapping_set_error also record writeback errors there.

To report those errors, we also need to keep an errseq_t in struct file
to act as a cursor.  This patch adds a dedicated field for that purpose,
which slots nicely into 4 bytes of padding at the end of struct file on
x86_64.

An earlier version of this patch used an O_PATH file descriptor to cue
the kernel that the open file should track the superblock error and not
the inode's writeback error.

I think that API is just too weird though.  This is simpler and should
make syncfs error reporting "just work" even if someone is multiplexing
fsync and syncfs on the same fds.

Signed-off-by: Jeff Layton 
Signed-off-by: Andrew Morton 
Reviewed-by: Jan Kara 
Cc: Andres Freund 
Cc: Matthew Wilcox 
Cc: Al Viro 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: David Howells 
Link: http://lkml.kernel.org/r/20200428135155.19223-1-jlayton@kernel.org
Link: http://lkml.kernel.org/r/20200428135155.19223-2-jlayton@kernel.org
Signed-off-by: Linus Torvalds

device-dax: don't leak kernel memory to user space after unloading kmem

2020-05-23T17:26:31+00:00

Assume we have kmem configured and loaded:

  [root@localhost ~]# cat /proc/iomem
  ...
  140000000-33fffffff : Persistent Memory$
    140000000-1481fffff : namespace0.0
    150000000-33fffffff : dax0.0
      150000000-33fffffff : System RAM

Assume we try to unload kmem. This force-unloading will work, even if
memory cannot get removed from the system.

  [root@localhost ~]# rmmod kmem
  [   86.380228] removing memory fails, because memory [0x0000000150000000-0x0000000157ffffff] is onlined
  ...
  [   86.431225] kmem dax0.0: DAX region [mem 0x150000000-0x33fffffff] cannot be hotremoved until the next reboot

Now, we can reconfigure the namespace:

  [root@localhost ~]# ndctl create-namespace --force --reconfig=namespace0.0 --mode=devdax
  [  131.409351] nd_pmem namespace0.0: could not reserve region [mem 0x140000000-0x33fffffff]dax
  [  131.410147] nd_pmem: probe of namespace0.0 failed with error -16namespace0.0 --mode=devdax
  ...

This fails as expected due to the busy memory resource, and the memory
cannot be used.  However, the dax0.0 device is removed, and along its
name.

The name of the memory resource now points at freed memory (name of the
device):

  [root@localhost ~]# cat /proc/iomem
  ...
  140000000-33fffffff : Persistent Memory
    140000000-1481fffff : namespace0.0
    150000000-33fffffff : �_�^7_��/_��wR��WQ���^��� ...
    150000000-33fffffff : System RAM

We have to make sure to duplicate the string.  While at it, remove the
superfluous setting of the name and fixup a stale comment.

Fixes: 9f960da72b25 ("device-dax: "Hotremove" persistent memory that is used like normal RAM")
Signed-off-by: David Hildenbrand 
Signed-off-by: Andrew Morton 
Cc: Dan Williams 
Cc: Vishal Verma 
Cc: Dave Jiang 
Cc: Pavel Tatashin 
Cc: Andrew Morton 
Cc: 	[5.3]
Link: http://lkml.kernel.org/r/20200508084217.9160-2-david@redhat.com
Signed-off-by: Linus Torvalds

dax: Move mandatory ->zero_page_range() check in alloc_dax()

2020-04-03T02:15:03+00:00

zero_page_range() dax operation is mandatory for dax devices. Right now
that check happens in dax_zero_page_range() function. Dan thinks that's
too late and its better to do the check earlier in alloc_dax().

I also modified alloc_dax() to return pointer with error code in it in
case of failure. Right now it returns NULL and caller assumes failure
happened due to -ENOMEM. But with this ->zero_page_range() check, I
need to return -EINVAL instead.

Signed-off-by: Vivek Goyal 
Link: https://lore.kernel.org/r/20200401161125.GB9398@redhat.com
Signed-off-by: Dan Williams

dax, pmem: Add a dax operation zero_page_range

2020-04-03T02:15:03+00:00

Add a dax operation zero_page_range, to zero a page. This will also clear any
known poison in the page being zeroed.

As of now, zeroing of one page is allowed in a single call. There
are no callers which are trying to zero more than a page in a single call.
Once we grow the callers which zero more than a page in single call, we
can add that support. Primary reason for not doing that yet is that this
will add little complexity in dm implementation where a range might be
spanning multiple underlying targets and one will have to split the range
into multiple sub ranges and call zero_page_range() on individual targets.

Suggested-by: Christoph Hellwig 
Signed-off-by: Vivek Goyal 
Reviewed-by: Pankaj Gupta 
Link: https://lore.kernel.org/r/20200228163456.1587-3-vgoyal@redhat.com
Signed-off-by: Dan Williams

dax: Get rid of fs_dax_get_by_host() helper

2020-01-16T17:52:27+00:00

Looks like nobody is using fs_dax_get_by_host() except fs_dax_get_by_bdev()
and it can easily use dax_get_by_host() instead.

IIUC, fs_dax_get_by_host() was only introduced so that one could compile
with CONFIG_FS_DAX=n and CONFIG_DAX=m. fs_dax_get_by_bdev() achieves
the same purpose and hence it looks like fs_dax_get_by_host() is not
needed anymore.

Signed-off-by: Vivek Goyal 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20200106181117.GA16248@redhat.com
Signed-off-by: Dan Williams