This patch is reworked from an earlier patch that Dan has posted:
https://patchwork.kernel.org/patch/10131727/
VM_MIXEDMAP is used by dax to direct mm paths like vm_normal_page() that
the memory page it is dealing with is not typical memory from the linear
map. The get_user_pages_fast() path, since it does not resolve the vma,
is already using {pte,pmd}_devmap() as a stand-in for VM_MIXEDMAP, so we
use that as a VM_MIXEDMAP replacement in some locations. In the cases
where there is no pte to consult we fallback to using vma_is_dax() to
detect the VM_MIXEDMAP special case.
Now that we have explicit driver pfn_t-flag opt-in/opt-out for
get_user_pages() support for DAX we can stop setting VM_MIXEDMAP. This
also means we no longer need to worry about safely manipulating vm_flags
in a future where we support dynamically changing the dax mode of a
file.
DAX should also now be supported with madvise_behavior(), vma_merge(),
and copy_page_range().
This patch has been tested against ndctl unit test. It has also been
tested against xfstests commit: 625515d using fake pmem created by
memmap and no additional issues have been observed.
Link: http://lkml.kernel.org/r/152847720311.55924.16999195879201817653.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
acpi_nfit_ctl is always set to a value. An incremental patch is provided
due to notice from testing in -next. The rest of the commits did not
exhibit issues.
* fix two fixes a return path in nsio_rw_bytes() that was not
returning "bytes remain" as expected for the function.
* fix three addresses an issue where applications polling on
scrub-completion for the NVDIMM may falsely wakeup and read the wrong
state value and cause hang.
* the test unit changed the persistent capability attribute to fix up a broken
assumption in the unit test infrastructure wrt the 'write_cache' attribute
* An output ratelimit to dev_info is introduced to the dax device
check_vma() function since this is easily triggered from userspace.
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Merge tag 'libnvdimm-fixes-4.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm fixes from Dave Jiang:
- ensure that a variable passed in by reference to acpi_nfit_ctl is
always set to a value. An incremental patch is provided due to notice
from testing in -next. The rest of the commits did not exhibit
issues.
- fix a return path in nsio_rw_bytes() that was not returning "bytes
remain" as expected for the function.
- address an issue where applications polling on scrub-completion for
the NVDIMM may falsely wakeup and read the wrong state value and
cause hang.
- change the test unit persistent capability attribute to fix up a
broken assumption in the unit test infrastructure wrt the
'write_cache' attribute
- ratelimit dev_info() in the dax device check_vma() function since
this is easily triggered from userspace
* tag 'libnvdimm-fixes-4.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
nfit: fix unchecked dereference in acpi_nfit_ctl
acpi, nfit: Fix scrub idle detection
tools/testing/nvdimm: advertise a write cache for nfit_test
acpi/nfit: fix cmd_rc for acpi_nfit_ctl to always return a value
dev-dax: check_vma: ratelimit dev_info-s
libnvdimm, pmem: Fix memcpy_mcsafe() return code handling in nsio_rw_bytes()
This is easily triggered from userspace, so let's ratelimit the
messages.
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Add an explicit check for QUEUE_FLAG_DAX to __bdev_dax_supported(). This
is needed for DM configurations where the first element in the dm-linear or
dm-stripe target supports DAX, but other elements do not. Without this
check __bdev_dax_supported() will pass for such devices, letting a
filesystem on that device mount with the DAX option.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Mike Snitzer <snitzer@redhat.com>
Fixes: commit 545ed20e6d ("dm: add infrastructure for DAX support")
Cc: stable@vger.kernel.org
Acked-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* DAX broke a fundamental assumption of truncate of file mapped pages.
The truncate path assumed that it is safe to disconnect a pinned page
from a file and let the filesystem reclaim the physical block. With DAX
the page is equivalent to the filesystem block. Introduce
dax_layout_busy_page() to enable filesystems to wait for pinned DAX
pages to be released. Without this wait a filesystem could allocate
blocks under active device-DMA to a new file.
* DAX arranges for the block layer to be bypassed and uses
dax_direct_access() + copy_to_iter() to satisfy read(2) calls.
However, the memcpy_mcsafe() facility is available through the pmem
block driver. In order to safely handle media errors, via the DAX
block-layer bypass, introduce copy_to_iter_mcsafe().
* Fix cache management policy relative to the ACPI NFIT Platform
Capabilities Structure to properly elide cache flushes when they are not
necessary. The table indicates whether CPU caches are power-fail
protected. Clarify that a deep flush is always performed on
REQ_{FUA,PREFLUSH} requests.
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Merge tag 'libnvdimm-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"This adds a user for the new 'bytes-remaining' updates to
memcpy_mcsafe() that you already received through Ingo via the
x86-dax- for-linus pull.
Not included here, but still targeting this cycle, is support for
handling memory media errors (poison) consumed via userspace dax
mappings.
Summary:
- DAX broke a fundamental assumption of truncate of file mapped
pages. The truncate path assumed that it is safe to disconnect a
pinned page from a file and let the filesystem reclaim the physical
block. With DAX the page is equivalent to the filesystem block.
Introduce dax_layout_busy_page() to enable filesystems to wait for
pinned DAX pages to be released. Without this wait a filesystem
could allocate blocks under active device-DMA to a new file.
- DAX arranges for the block layer to be bypassed and uses
dax_direct_access() + copy_to_iter() to satisfy read(2) calls.
However, the memcpy_mcsafe() facility is available through the pmem
block driver. In order to safely handle media errors, via the DAX
block-layer bypass, introduce copy_to_iter_mcsafe().
- Fix cache management policy relative to the ACPI NFIT Platform
Capabilities Structure to properly elide cache flushes when they
are not necessary. The table indicates whether CPU caches are
power-fail protected. Clarify that a deep flush is always performed
on REQ_{FUA,PREFLUSH} requests"
* tag 'libnvdimm-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (21 commits)
dax: Use dax_write_cache* helpers
libnvdimm, pmem: Do not flush power-fail protected CPU caches
libnvdimm, pmem: Unconditionally deep flush on *sync
libnvdimm, pmem: Complete REQ_FLUSH => REQ_PREFLUSH
acpi, nfit: Remove ecc_unit_size
dax: dax_insert_mapping_entry always succeeds
libnvdimm, e820: Register all pmem resources
libnvdimm: Debug probe times
linvdimm, pmem: Preserve read-only setting for pmem devices
x86, nfit_test: Add unit test for memcpy_mcsafe()
pmem: Switch to copy_to_iter_mcsafe()
dax: Report bytes remaining in dax_iomap_actor()
dax: Introduce a ->copy_to_iter dax operation
uio, lib: Fix CONFIG_ARCH_HAS_UACCESS_MCSAFE compilation
xfs, dax: introduce xfs_break_dax_layouts()
xfs: prepare xfs_break_layouts() for another layout type
xfs: prepare xfs_break_layouts() to be called with XFS_MMAPLOCK_EXCL
mm, fs, dax: handle layout changes to pinned dax mappings
mm: fix __gup_device_huge vs unmap
mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS
...
- Use overflow helpers in 2-factor allocators (Kees, Rasmus)
- Introduce overflow test module (Rasmus, Kees)
- Introduce saturating size helper functions (Matthew, Kees)
- Treewide use of struct_size() for allocators (Kees)
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Merge tag 'overflow-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull overflow updates from Kees Cook:
"This adds the new overflow checking helpers and adds them to the
2-factor argument allocators. And this adds the saturating size
helpers and does a treewide replacement for the struct_size() usage.
Additionally this adds the overflow testing modules to make sure
everything works.
I'm still working on the treewide replacements for allocators with
"simple" multiplied arguments:
*alloc(a * b, ...) -> *alloc_array(a, b, ...)
and
*zalloc(a * b, ...) -> *calloc(a, b, ...)
as well as the more complex cases, but that's separable from this
portion of the series. I expect to have the rest sent before -rc1
closes; there are a lot of messy cases to clean up.
Summary:
- Introduce arithmetic overflow test helper functions (Rasmus)
- Use overflow helpers in 2-factor allocators (Kees, Rasmus)
- Introduce overflow test module (Rasmus, Kees)
- Introduce saturating size helper functions (Matthew, Kees)
- Treewide use of struct_size() for allocators (Kees)"
* tag 'overflow-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
treewide: Use struct_size() for devm_kmalloc() and friends
treewide: Use struct_size() for vmalloc()-family
treewide: Use struct_size() for kmalloc()-family
device: Use overflow helpers for devm_kmalloc()
mm: Use overflow helpers in kvmalloc()
mm: Use overflow helpers in kmalloc_array*()
test_overflow: Add memory allocation overflow tests
overflow.h: Add allocation size calculation helpers
test_overflow: Report test failures
test_overflow: macrofy some more, do more tests for free
lib: add runtime test of check_*_overflow functions
compiler.h: enable builtin overflow checkers and add fallback code
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL);
This patch makes the changes for kmalloc()-family (and kvmalloc()-family)
uses. It was done via automatic conversion with manual review for the
"CHECKME" non-standard cases noted below, using the following Coccinelle
script:
// pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len *
// sizeof *pkey_cache->table, GFP_KERNEL);
@@
identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc";
expression GFP;
identifier VAR, ELEMENT;
expression COUNT;
@@
- alloc(sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP)
+ alloc(struct_size(VAR, ELEMENT, COUNT), GFP)
// mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL);
@@
identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc";
expression GFP;
identifier VAR, ELEMENT;
expression COUNT;
@@
- alloc(sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP)
+ alloc(struct_size(VAR, ELEMENT, COUNT), GFP)
// Same pattern, but can't trivially locate the trailing element name,
// or variable name.
@@
identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc";
expression GFP;
expression SOMETHING, COUNT, ELEMENT;
@@
- alloc(sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP)
+ alloc(CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP)
Signed-off-by: Kees Cook <keescook@chromium.org>
Use dax_write_cache() and dax_write_cache_enabled() instead of open coding
the bit operations.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The function return values are confusing with the way the function is
named. We expect a true or false return value but it actually returns
0/-errno. This makes the code very confusing. Changing the return values
to return a bool where if DAX is supported then return true and no DAX
support returns false.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Change bdev_dax_supported so it takes a bdev parameter. This enables
multi-device filesystems like xfs to check that a dax device can work for
the particular filesystem. Once that's in place, actually fix all the
parts of XFS where we need to be able to distinguish between datadev and
rtdev.
This patch fixes the problem where we screw up the dax support checking
in xfs if the datadev and rtdev have different dax capabilities.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
[rez: Re-added __bdev_dax_supported() for !CONFIG_FS_DAX cases]
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Similar to the ->copy_from_iter() operation, a platform may want to
deploy an architecture or device specific routine for handling reads
from a dax_device like /dev/pmemX. On x86 this routine will point to a
machine check safe version of copy_to_iter(). For now, add the plumbing
to device-mapper and the dax core.
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
In preparation for fixing dax-dma-vs-unmap issues, filesystems need to
be able to rely on the fact that they will get wakeups on dev_pagemap
page-idle events. Introduce MEMORY_DEVICE_FS_DAX and
generic_dax_page_free() as common indicator / infrastructure for dax
filesytems to require. With this change there are no users of the
MEMORY_DEVICE_HOST designation, so remove it.
The HMM sub-system extended dev_pagemap to arrange a callback when a
dev_pagemap managed page is freed. Since a dev_pagemap page is free /
idle when its reference count is 1 it requires an additional branch to
check the page-type at put_page() time. Given put_page() is a hot-path
we do not want to incur that check if HMM is not in use, so a static
branch is used to avoid that overhead when not necessary.
Now, the FS_DAX implementation wants to reuse this mechanism for
receiving dev_pagemap ->page_free() callbacks. Rework the HMM-specific
static-key into a generic mechanism that either HMM or FS_DAX code paths
can enable.
For ARCH=um builds, and any other arch that lacks ZONE_DEVICE support,
care must be taken to compile out the DEV_PAGEMAP_OPS infrastructure.
However, we still need to support FS_DAX in the FS_DAX_LIMITED case
implemented by the s390/dcssblk driver.
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Thomas Meyer <thomas@m3y3r.de>
Reported-by: Dave Jiang <dave.jiang@intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
MAP_SYNC is a nop for device-dax. Allow MAP_SYNC to succeed on device-dax
to eliminate special casing between device-dax and fs-dax as to when the
flag can be specified. Device-dax users already implicitly assume that they do
not need to call fsync(), and this enables them to explicitly check for this
capability.
Cc: <stable@vger.kernel.org>
Fixes: b6fb293f24 ("mm: Define MAP_SYNC and VM_SYNC flags")
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* A rework of the filesytem-dax implementation provides for detection of
unmap operations (truncate / hole punch) colliding with in-progress
device-DMA. A fix for these collisions remains a work-in-progress
pending resolution of truncate latency and starvation regressions.
* The of_pmem driver expands the users of libnvdimm outside of x86 and
ACPI to describe an implementation of persistent memory on PowerPC with
Open Firmware / Device tree.
* Address Range Scrub (ARS) handling is completely rewritten to account for
the fact that ARS may run for 100s of seconds and there is no platform
defined way to cancel it. ARS will now no longer block namespace
initialization.
* The NVDIMM Namespace Label implementation is updated to handle label
areas as small as 1K, down from 128K.
* Miscellaneous cleanups and updates to unit test infrastructure.
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Merge tag 'libnvdimm-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"This cycle was was not something I ever want to repeat as there were
several late changes that have only now just settled.
Half of the branch up to commit d2c997c0f1 ("fs, dax: use
page->mapping to warn...") have been in -next for several releases.
The of_pmem driver and the address range scrub rework were late
arrivals, and the dax work was scaled back at the last moment.
The of_pmem driver missed a previous merge window due to an oversight.
A sense of obligation to rectify that miss is why it is included for
4.17. It has acks from PowerPC folks. Stephen reported a build failure
that only occurs when merging it with your latest tree, for now I have
fixed that up by disabling modular builds of of_pmem. A test merge
with your tree has received a build success report from the 0day robot
over 156 configs.
An initial version of the ARS rework was submitted before the merge
window. It is self contained to libnvdimm, a net code reduction, and
passing all unit tests.
The filesystem-dax changes are based on the wait_var_event()
functionality from tip/sched/core. However, late review feedback
showed that those changes regressed truncate performance to a large
degree. The branch was rewound to drop the truncate behavior change
and now only includes preparation patches and cleanups (with full acks
and reviews). The finalization of this dax-dma-vs-trnucate work will
need to wait for 4.18.
Summary:
- A rework of the filesytem-dax implementation provides for detection
of unmap operations (truncate / hole punch) colliding with
in-progress device-DMA. A fix for these collisions remains a
work-in-progress pending resolution of truncate latency and
starvation regressions.
- The of_pmem driver expands the users of libnvdimm outside of x86
and ACPI to describe an implementation of persistent memory on
PowerPC with Open Firmware / Device tree.
- Address Range Scrub (ARS) handling is completely rewritten to
account for the fact that ARS may run for 100s of seconds and there
is no platform defined way to cancel it. ARS will now no longer
block namespace initialization.
- The NVDIMM Namespace Label implementation is updated to handle
label areas as small as 1K, down from 128K.
- Miscellaneous cleanups and updates to unit test infrastructure"
* tag 'libnvdimm-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (39 commits)
libnvdimm, of_pmem: workaround OF_NUMA=n build error
nfit, address-range-scrub: add module option to skip initial ars
nfit, address-range-scrub: rework and simplify ARS state machine
nfit, address-range-scrub: determine one platform max_ars value
powerpc/powernv: Create platform devs for nvdimm buses
doc/devicetree: Persistent memory region bindings
libnvdimm: Add device-tree based driver
libnvdimm: Add of_node to region and bus descriptors
libnvdimm, region: quiet region probe
libnvdimm, namespace: use a safe lookup for dimm device name
libnvdimm, dimm: fix dpa reservation vs uninitialized label area
libnvdimm, testing: update the default smart ctrl_temperature
libnvdimm, testing: Add emulation for smart injection commands
nfit, address-range-scrub: introduce nfit_spa->ars_state
libnvdimm: add an api to cast a 'struct nd_region' to its 'struct device'
nfit, address-range-scrub: fix scrub in-progress reporting
dax, dm: allow device-mapper to operate without dax support
dax: introduce CONFIG_DAX_DRIVER
fs, dax: use page->mapping to warn if truncate collides with a busy page
ext2, dax: introduce ext2_dax_aops
...
Given that device-dax is making similar page mapping size guarantees as
hugetlbfs, emit the size in smaps and any other kernel path that
requests the mapping size of a vma.
Link: http://lkml.kernel.org/r/151996255287.27922.18397777516059080245.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In support of allowing device-mapper to compile out idle/dead code when
there are no dax providers in the system, introduce the DAX_DRIVER
symbol. This is selected by all leaf drivers that device-mapper might be
layered on top. This allows device-mapper to conditionally 'select DAX'
only when a provider is present.
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Reported-by: Bart Van Assche <Bart.VanAssche@wdc.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
In preparation for examining the busy state of dax pages in the truncate
path, switch from sectors to pfns in the radix.
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Use module_nd_driver() instead of having module_init() and
module_exit() callbacks which just call nd_driver_register() and
nd_driver_unregister().
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Dynamic debug can be instructed to add the function name to the debug
output using the +f switch, so there is no need for the dax modules to
do it again. If a user decides to add the +f switch for the dax modules'
dynamic debug this results in double prints of the function name.
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
In Patch:
[7a862fb] brd: remove dax support
Dan Williams has removed the only might_sleep
implementation of ->direct_access.
So we no longer need to check for it.
CC: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Boaz Harrosh <boazh@netapp.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The trailing semicolon is an empty statement that does no operation.
Removing it since it doesn't do anything.
Signed-off-by: Luis de Bethencourt <luisbg@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
If a dax buffer from a device that does not map pages is passed to
read(2) or write(2) as a target for direct-I/O it triggers SIGBUS. If
gdb attempts to examine the contents of a dax buffer from a device that
does not map pages it triggers SIGBUS. If fork(2) is called on a process
with a dax mapping from a device that does not map pages it triggers
SIGBUS. 'struct page' is required otherwise several kernel code paths
break in surprising ways. Disable filesystem-dax on devices that do not
map pages.
In addition to needing pfn_to_page() to be valid we also require devmap
pages. We need this to detect dax pages in the get_user_pages_fast()
path and so that we can stop managing the VM_MIXEDMAP flag. For DAX
drivers that have not supported get_user_pages() to date we allow them
to opt-in to supporting DAX with the CONFIG_FS_DAX_LIMITED configuration
option which requires ->direct_access() to return pfn_t_special() pfns.
This leaves DAX support in brd disabled and scheduled for removal.
Note that when the initial dax support was being merged a few years back
there was concern that struct page was unsuitable for use with next
generation persistent memory devices. The theoretical concern was that
struct page access, being such a hotly used data structure in the
kernel, would lead to media wear out. While that was a reasonable
conservative starting position it has not held true in practice. We have
long since committed to using devm_memremap_pages() to support higher
order kernel functionality that needs get_user_pages() and
pfn_to_page().
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This new interface is similar to how struct device (and many others)
work. The caller initializes a 'struct dev_pagemap' as required
and calls 'devm_memremap_pages'. This allows the pagemap structure to
be embedded in another structure and thus container_of can be used. In
this way application specific members can be stored in a containing
struct.
This will be used by the P2P infrastructure and HMM could probably
be cleaned up to use it as well (instead of having it's own, similar
'hmm_devmem_pages_create' function).
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Similar to how device-dax enforces that the 'address', 'offset', and
'len' parameters to mmap() be aligned to the device's fundamental
alignment, the same constraints apply to munmap(). Implement ->split()
to fail munmap calls that violate the alignment constraint.
Otherwise, we later fail VM_BUG_ON checks in the unmap_page_range() path
with crash signatures of the form:
vma ffff8800b60c8a88 start 00007f88c0000000 end 00007f88c0e00000
next (null) prev (null) mm ffff8800b61150c0
prot 8000000000000027 anon_vma (null) vm_ops ffffffffa0091240
pgoff 0 file ffff8800b638ef80 private_data (null)
flags: 0x380000fb(read|write|shared|mayread|maywrite|mayexec|mayshare|softdirty|mixedmap|hugepage)
------------[ cut here ]------------
kernel BUG at mm/huge_memory.c:2014!
[..]
RIP: 0010:__split_huge_pud+0x12a/0x180
[..]
Call Trace:
unmap_page_range+0x245/0xa40
? __vma_adjust+0x301/0x990
unmap_vmas+0x4c/0xa0
unmap_region+0xae/0x120
? __vma_rb_erase+0x11a/0x230
do_munmap+0x276/0x410
vm_munmap+0x6a/0xa0
SyS_munmap+0x1d/0x30
Link: http://lkml.kernel.org/r/151130418681.4029.7118245855057952010.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: dee4107924 ("/dev/dax, core: file operations and dax-mmap")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Jeff Moyer <jmoyer@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Introduce MAP_SYNC and MAP_SHARED_VALIDATE, a mechanism to enable
'userspace flush' of persistent memory updates via filesystem-dax
mappings. It arranges for any filesystem metadata updates that may be
required to satisfy a write fault to also be flushed ("on disk") before
the kernel returns to userspace from the fault handler. Effectively
every write-fault that dirties metadata completes an fsync() before
returning from the fault handler. The new MAP_SHARED_VALIDATE mapping
type guarantees that the MAP_SYNC flag is validated as supported by the
filesystem's ->mmap() file operation.
* Add support for the standard ACPI 6.2 label access methods that
replace the NVDIMM_FAMILY_INTEL (vendor specific) label methods. This
enables interoperability with environments that only implement the
standardized methods.
* Add support for the ACPI 6.2 NVDIMM media error injection methods.
* Add support for the NVDIMM_FAMILY_INTEL v1.6 DIMM commands for latch
last shutdown status, firmware update, SMART error injection, and
SMART alarm threshold control.
* Cleanup physical address information disclosures to be root-only.
* Fix revalidation of the DIMM "locked label area" status to support
dynamic unlock of the label area.
* Expand unit test infrastructure to mock the ACPI 6.2 Translate SPA
(system-physical-address) command and error injection commands.
Acknowledgements that came after the commits were pushed to -next:
957ac8c421 dax: fix PMD faults on zero-length files
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
a39e596baa xfs: support for synchronous DAX faults
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
7b565c9f96 xfs: Implement xfs_filemap_pfn_mkwrite() using __xfs_filemap_fault()
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
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Merge tag 'libnvdimm-for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm and dax updates from Dan Williams:
"Save for a few late fixes, all of these commits have shipped in -next
releases since before the merge window opened, and 0day has given a
build success notification.
The ext4 touches came from Jan, and the xfs touches have Darrick's
reviewed-by. An xfstest for the MAP_SYNC feature has been through
a few round of reviews and is on track to be merged.
- Introduce MAP_SYNC and MAP_SHARED_VALIDATE, a mechanism to enable
'userspace flush' of persistent memory updates via filesystem-dax
mappings. It arranges for any filesystem metadata updates that may
be required to satisfy a write fault to also be flushed ("on disk")
before the kernel returns to userspace from the fault handler.
Effectively every write-fault that dirties metadata completes an
fsync() before returning from the fault handler. The new
MAP_SHARED_VALIDATE mapping type guarantees that the MAP_SYNC flag
is validated as supported by the filesystem's ->mmap() file
operation.
- Add support for the standard ACPI 6.2 label access methods that
replace the NVDIMM_FAMILY_INTEL (vendor specific) label methods.
This enables interoperability with environments that only implement
the standardized methods.
- Add support for the ACPI 6.2 NVDIMM media error injection methods.
- Add support for the NVDIMM_FAMILY_INTEL v1.6 DIMM commands for
latch last shutdown status, firmware update, SMART error injection,
and SMART alarm threshold control.
- Cleanup physical address information disclosures to be root-only.
- Fix revalidation of the DIMM "locked label area" status to support
dynamic unlock of the label area.
- Expand unit test infrastructure to mock the ACPI 6.2 Translate SPA
(system-physical-address) command and error injection commands.
Acknowledgements that came after the commits were pushed to -next:
- 957ac8c421 ("dax: fix PMD faults on zero-length files"):
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
- a39e596baa ("xfs: support for synchronous DAX faults") and
7b565c9f96 ("xfs: Implement xfs_filemap_pfn_mkwrite() using __xfs_filemap_fault()")
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>"
* tag 'libnvdimm-for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (49 commits)
acpi, nfit: add 'Enable Latch System Shutdown Status' command support
dax: fix general protection fault in dax_alloc_inode
dax: fix PMD faults on zero-length files
dax: stop requiring a live device for dax_flush()
brd: remove dax support
dax: quiet bdev_dax_supported()
fs, dax: unify IOMAP_F_DIRTY read vs write handling policy in the dax core
tools/testing/nvdimm: unit test clear-error commands
acpi, nfit: validate commands against the device type
tools/testing/nvdimm: stricter bounds checking for error injection commands
xfs: support for synchronous DAX faults
xfs: Implement xfs_filemap_pfn_mkwrite() using __xfs_filemap_fault()
ext4: Support for synchronous DAX faults
ext4: Simplify error handling in ext4_dax_huge_fault()
dax: Implement dax_finish_sync_fault()
dax, iomap: Add support for synchronous faults
mm: Define MAP_SYNC and VM_SYNC flags
dax: Allow tuning whether dax_insert_mapping_entry() dirties entry
dax: Allow dax_iomap_fault() to return pfn
dax: Fix comment describing dax_iomap_fault()
...
Don't crash in case of allocation failure in dax_alloc_inode.
syzkaller hit the following crash on e4880bc5df
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
[..]
RIP: 0010:dax_alloc_inode+0x3b/0x70 drivers/dax/super.c:348
Call Trace:
alloc_inode+0x65/0x180 fs/inode.c:208
new_inode_pseudo+0x69/0x190 fs/inode.c:890
new_inode+0x1c/0x40 fs/inode.c:919
mount_pseudo_xattr+0x288/0x560 fs/libfs.c:261
mount_pseudo include/linux/fs.h:2137 [inline]
dax_mount+0x2e/0x40 drivers/dax/super.c:388
mount_fs+0x66/0x2d0 fs/super.c:1223
Cc: <stable@vger.kernel.org>
Fixes: 7b6be8444e ("dax: refactor dax-fs into a generic provider...")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Now that dax_flush() is no longer a driver callback (commit c3ca015fab
"dax: remove the pmem_dax_ops->flush abstraction"), stop requiring the
dax_read_lock() to be held and the device to be alive. This is in
preparation for switching filesystem-dax to store pfns instead of
sectors in the radix.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Before we add another failure reason, quiet the existing log messages.
Leave it to the caller to decide if bdev_dax_supported() failures are
errors worth emitting to the log.
Reported-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pr_err() messages should terminated with a new-line to avoid
other messages being concatenated onto the end.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
- Constify a few variables in DM core and DM integrity
- Add bufio optimization and checksum failure accounting to DM integrity
- Fix DM integrity to avoid checking integrity of failed reads
- Fix DM integrity to use init_completion
- A couple DM log-writes target fixes
- Simplify DAX flushing by eliminating the unnecessary flush abstraction
that was stood up for DM's use.
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Merge tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- Some request-based DM core and DM multipath fixes and cleanups
- Constify a few variables in DM core and DM integrity
- Add bufio optimization and checksum failure accounting to DM
integrity
- Fix DM integrity to avoid checking integrity of failed reads
- Fix DM integrity to use init_completion
- A couple DM log-writes target fixes
- Simplify DAX flushing by eliminating the unnecessary flush
abstraction that was stood up for DM's use.
* tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dax: remove the pmem_dax_ops->flush abstraction
dm integrity: use init_completion instead of COMPLETION_INITIALIZER_ONSTACK
dm integrity: make blk_integrity_profile structure const
dm integrity: do not check integrity for failed read operations
dm log writes: fix >512b sectorsize support
dm log writes: don't use all the cpu while waiting to log blocks
dm ioctl: constify ioctl lookup table
dm: constify argument arrays
dm integrity: count and display checksum failures
dm integrity: optimize writing dm-bufio buffers that are partially changed
dm rq: do not update rq partially in each ending bio
dm rq: make dm-sq requeuing behavior consistent with dm-mq behavior
dm mpath: complain about unsupported __multipath_map_bio() return values
dm mpath: avoid that building with W=1 causes gcc 7 to complain about fall-through
Commit abebfbe2f7 ("dm: add ->flush() dax operation support") is
buggy. A DM device may be composed of multiple underlying devices and
all of them need to be flushed. That commit just routes the flush
request to the first device and ignores the other devices.
It could be fixed by adding more complex logic to the device mapper. But
there is only one implementation of the method pmem_dax_ops->flush - that
is pmem_dax_flush() - and it calls arch_wb_cache_pmem(). Consequently, we
don't need the pmem_dax_ops->flush abstraction at all, we can call
arch_wb_cache_pmem() directly from dax_flush() because dax_dev->ops->flush
can't ever reach anything different from arch_wb_cache_pmem().
It should be also pointed out that for some uses of persistent memory it
is needed to flush only a very small amount of data (such as 1 cacheline),
and it would be overkill if we go through that device mapper machinery for
a single flushed cache line.
Fix this by removing the pmem_dax_ops->flush abstraction and call
arch_wb_cache_pmem() directly from dax_flush(). Also, remove the device
mapper code that forwards the flushes.
Fixes: abebfbe2f7 ("dm: add ->flush() dax operation support")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The 0day kbuild robot reports:
>> drivers//dax/super.c:64:20: error: redefinition of 'fs_dax_get_by_bdev'
struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
^~~~~~~~~~~~~~~~~~
In file included from drivers//dax/super.c:22:0:
include/linux/dax.h:76:34: note: previous definition of 'fs_dax_get_by_bdev' was here
static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
^~~~~~~~~~~~~~~~~~
Protect the definition of fs_dax_get_by_bdev() in drivers/dax/super.c
with an ifdef.
Fixes: 78f3547350 ("dax: introduce a fs_dax_get_by_bdev() helper")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Add a helper that can replace the following common pattern:
if (blk_queue_dax(bdev->bd_queue))
fs_dax_get_by_host(bdev->bd_disk->disk_name);
This will be used to move dax_device lookup from iomap-operation time to
fs-mount time.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
inefficiencies in the on-disk journal device layout. Another that
makes use of the block layer's on-stack plugging when writing the
journal.
- A dm-bufio fix for the blk_status_t conversion that went in during the
merge window.
- A few DM raid fixes that address correctness when suspending the
device and a validation fix for validation that occurs during device
activation.
- A couple DM zoned target fixes. Important one being the fix to not
use GFP_KERNEL in the IO path due to concerns about deadlock in
low-memory conditions (e.g. swap over a DM zoned device, etc).
- A DM DAX device fix to make sure dm_dax_flush() is called if the
underlying DAX device is operating as a write cache.
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Merge tag 'for-4.13/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper fixes from Mike Snitzer:
- a few DM integrity fixes that improve performance. One that address
inefficiencies in the on-disk journal device layout. Another that
makes use of the block layer's on-stack plugging when writing the
journal.
- a dm-bufio fix for the blk_status_t conversion that went in during
the merge window.
- a few DM raid fixes that address correctness when suspending the
device and a validation fix for validation that occurs during device
activation.
- a couple DM zoned target fixes. Important one being the fix to not
use GFP_KERNEL in the IO path due to concerns about deadlock in
low-memory conditions (e.g. swap over a DM zoned device, etc).
- a DM DAX device fix to make sure dm_dax_flush() is called if the
underlying DAX device is operating as a write cache.
* tag 'for-4.13/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm, dax: Make sure dm_dax_flush() is called if device supports it
dm verity fec: fix GFP flags used with mempool_alloc()
dm zoned: use GFP_NOIO in I/O path
dm zoned: remove test for impossible REQ_OP_FLUSH conditions
dm raid: bump target version
dm raid: avoid mddev->suspended access
dm raid: fix activation check in validate_raid_redundancy()
dm raid: remove WARN_ON() in raid10_md_layout_to_format()
dm bufio: fix error code in dm_bufio_write_dirty_buffers()
dm integrity: test for corrupted disk format during table load
dm integrity: WARN_ON if variables representing journal usage get out of sync
dm integrity: use plugging when writing the journal
dm integrity: fix inefficient allocation of journal space
Currently dm_dax_flush() is not being called, even if underlying dax
device supports write cache, because DAXDEV_WRITE_CACHE is not being
propagated up to the DM dax device.
If the underlying dax device supports write cache, set
DAXDEV_WRITE_CACHE on the DM dax device. This will cause dm_dax_flush()
to be called.
Fixes: abebfbe2f7 ("dm: add ->flush() dax operation support")
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Fix warnings of the form...
WARNING: CPU: 10 PID: 4983 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x62/0x80
sysfs: cannot create duplicate filename '/class/dax/dax12.0'
Call Trace:
dump_stack+0x63/0x86
__warn+0xcb/0xf0
warn_slowpath_fmt+0x5a/0x80
? kernfs_path_from_node+0x4f/0x60
sysfs_warn_dup+0x62/0x80
sysfs_do_create_link_sd.isra.2+0x97/0xb0
sysfs_create_link+0x25/0x40
device_add+0x266/0x630
devm_create_dax_dev+0x2cf/0x340 [dax]
dax_pmem_probe+0x1f5/0x26e [dax_pmem]
nvdimm_bus_probe+0x71/0x120
...by reusing the namespace id for the device-dax instance name.
Now that we have decided that there will never by more than one
device-dax instance per libnvdimm-namespace parent device [1], we can
directly reuse the namepace ids. There are some possible follow-on
cleanups, but those are saved for a later patch to simplify the -stable
backport.
[1]: https://lists.01.org/pipermail/linux-nvdimm/2016-December/008266.html
Fixes: 98a29c39dc ("libnvdimm, namespace: allow creation of multiple pmem...")
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: <stable@vger.kernel.org>
Reported-by: Dariusz Dokupil <dariusz.dokupil@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Dan Carpenter reports:
The patch 7b6be8444e0f: "dax: refactor dax-fs into a generic provider
of 'struct dax_device' instances" from Apr 11, 2017, leads to the
following static checker warning:
drivers/dax/device.c:643 devm_create_dev_dax()
warn: passing zero to 'ERR_PTR'
Fix the case where we inadvertently leak 0 to ERR_PTR() by setting at
every error case, and make it clear that 'count' is never 0.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Merge tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux
Pull Writeback error handling updates from Jeff Layton:
"This pile represents the bulk of the writeback error handling fixes
that I have for this cycle. Some of the earlier patches in this pile
may look trivial but they are prerequisites for later patches in the
series.
The aim of this set is to improve how we track and report writeback
errors to userland. Most applications that care about data integrity
will periodically call fsync/fdatasync/msync to ensure that their
writes have made it to the backing store.
For a very long time, we have tracked writeback errors using two flags
in the address_space: AS_EIO and AS_ENOSPC. Those flags are set when a
writeback error occurs (via mapping_set_error) and are cleared as a
side-effect of filemap_check_errors (as you noted yesterday). This
model really sucks for userland.
Only the first task to call fsync (or msync or fdatasync) will see the
error. Any subsequent task calling fsync on a file will get back 0
(unless another writeback error occurs in the interim). If I have
several tasks writing to a file and calling fsync to ensure that their
writes got stored, then I need to have them coordinate with one
another. That's difficult enough, but in a world of containerized
setups that coordination may even not be possible.
But wait...it gets worse!
The calls to filemap_check_errors can be buried pretty far down in the
call stack, and there are internal callers of filemap_write_and_wait
and the like that also end up clearing those errors. Many of those
callers ignore the error return from that function or return it to
userland at nonsensical times (e.g. truncate() or stat()). If I get
back -EIO on a truncate, there is no reason to think that it was
because some previous writeback failed, and a subsequent fsync() will
(incorrectly) return 0.
This pile aims to do three things:
1) ensure that when a writeback error occurs that that error will be
reported to userland on a subsequent fsync/fdatasync/msync call,
regardless of what internal callers are doing
2) report writeback errors on all file descriptions that were open at
the time that the error occurred. This is a user-visible change,
but I think most applications are written to assume this behavior
anyway. Those that aren't are unlikely to be hurt by it.
3) document what filesystems should do when there is a writeback
error. Today, there is very little consistency between them, and a
lot of cargo-cult copying. We need to make it very clear what
filesystems should do in this situation.
To achieve this, the set adds a new data type (errseq_t) and then
builds new writeback error tracking infrastructure around that. Once
all of that is in place, we change the filesystems to use the new
infrastructure for reporting wb errors to userland.
Note that this is just the initial foray into cleaning up this mess.
There is a lot of work remaining here:
1) convert the rest of the filesystems in a similar fashion. Once the
initial set is in, then I think most other fs' will be fairly
simple to convert. Hopefully most of those can in via individual
filesystem trees.
2) convert internal waiters on writeback to use errseq_t for
detecting errors instead of relying on the AS_* flags. I have some
draft patches for this for ext4, but they are not quite ready for
prime time yet.
This was a discussion topic this year at LSF/MM too. If you're
interested in the gory details, LWN has some good articles about this:
https://lwn.net/Articles/718734/https://lwn.net/Articles/724307/"
* tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
btrfs: minimal conversion to errseq_t writeback error reporting on fsync
xfs: minimal conversion to errseq_t writeback error reporting
ext4: use errseq_t based error handling for reporting data writeback errors
fs: convert __generic_file_fsync to use errseq_t based reporting
block: convert to errseq_t based writeback error tracking
dax: set errors in mapping when writeback fails
Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors
mm: set both AS_EIO/AS_ENOSPC and errseq_t in mapping_set_error
fs: new infrastructure for writeback error handling and reporting
lib: add errseq_t type and infrastructure for handling it
mm: don't TestClearPageError in __filemap_fdatawait_range
mm: clear AS_EIO/AS_ENOSPC when writeback initiation fails
jbd2: don't clear and reset errors after waiting on writeback
buffer: set errors in mapping at the time that the error occurs
fs: check for writeback errors after syncing out buffers in generic_file_fsync
buffer: use mapping_set_error instead of setting the flag
mm: fix mapping_set_error call in me_pagecache_dirty
* Introduce the _flushcache() family of memory copy helpers and use them
for persistent memory write operations on x86. The _flushcache()
semantic indicates that the cache is either bypassed for the copy
operation (movnt) or any lines dirtied by the copy operation are
written back (clwb, clflushopt, or clflush).
* Extend dax_operations with ->copy_from_iter() and ->flush()
operations. These operations and other infrastructure updates allow
all persistent memory specific dax functionality to be pushed into
libnvdimm and the pmem driver directly. It also allows dax-specific
sysfs attributes to be linked to a host device, for example:
/sys/block/pmem0/dax/write_cache
* Add support for the new NVDIMM platform/firmware mechanisms introduced
in ACPI 6.2 and UEFI 2.7. This support includes the v1.2 namespace
label format, extensions to the address-range-scrub command set, new
error injection commands, and a new BTT (block-translation-table)
layout. These updates support inter-OS and pre-OS compatibility.
* Fix a longstanding memory corruption bug in nfit_test.
* Make the pmem and nvdimm-region 'badblocks' sysfs files poll(2)
capable.
* Miscellaneous fixes and small updates across libnvdimm and the nfit
driver.
Acknowledgements that came after the branch was pushed:
commit 6aa734a2f3 "libnvdimm, region, pmem: fix 'badblocks'
sysfs_get_dirent() reference lifetime"
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
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Merge tag 'libnvdimm-for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"libnvdimm updates for the latest ACPI and UEFI specifications. This
pull request also includes new 'struct dax_operations' enabling to
undo the abuse of copy_user_nocache() for copy operations to pmem.
The dax work originally missed 4.12 to address concerns raised by Al.
Summary:
- Introduce the _flushcache() family of memory copy helpers and use
them for persistent memory write operations on x86. The
_flushcache() semantic indicates that the cache is either bypassed
for the copy operation (movnt) or any lines dirtied by the copy
operation are written back (clwb, clflushopt, or clflush).
- Extend dax_operations with ->copy_from_iter() and ->flush()
operations. These operations and other infrastructure updates allow
all persistent memory specific dax functionality to be pushed into
libnvdimm and the pmem driver directly. It also allows dax-specific
sysfs attributes to be linked to a host device, for example:
/sys/block/pmem0/dax/write_cache
- Add support for the new NVDIMM platform/firmware mechanisms
introduced in ACPI 6.2 and UEFI 2.7. This support includes the v1.2
namespace label format, extensions to the address-range-scrub
command set, new error injection commands, and a new BTT
(block-translation-table) layout. These updates support inter-OS
and pre-OS compatibility.
- Fix a longstanding memory corruption bug in nfit_test.
- Make the pmem and nvdimm-region 'badblocks' sysfs files poll(2)
capable.
- Miscellaneous fixes and small updates across libnvdimm and the nfit
driver.
Acknowledgements that came after the branch was pushed: commit
6aa734a2f3 ("libnvdimm, region, pmem: fix 'badblocks'
sysfs_get_dirent() reference lifetime") was reviewed by Toshi Kani
<toshi.kani@hpe.com>"
* tag 'libnvdimm-for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (42 commits)
libnvdimm, namespace: record 'lbasize' for pmem namespaces
acpi/nfit: Issue Start ARS to retrieve existing records
libnvdimm: New ACPI 6.2 DSM functions
acpi, nfit: Show bus_dsm_mask in sysfs
libnvdimm, acpi, nfit: Add bus level dsm mask for pass thru.
acpi, nfit: Enable DSM pass thru for root functions.
libnvdimm: passthru functions clear to send
libnvdimm, btt: convert some info messages to warn/err
libnvdimm, region, pmem: fix 'badblocks' sysfs_get_dirent() reference lifetime
libnvdimm: fix the clear-error check in nsio_rw_bytes
libnvdimm, btt: fix btt_rw_page not returning errors
acpi, nfit: quiet invalid block-aperture-region warnings
libnvdimm, btt: BTT updates for UEFI 2.7 format
acpi, nfit: constify *_attribute_group
libnvdimm, pmem: disable dax flushing when pmem is fronting a volatile region
libnvdimm, pmem, dax: export a cache control attribute
dax: convert to bitmask for flags
dax: remove default copy_from_iter fallback
libnvdimm, nfit: enable support for volatile ranges
libnvdimm, pmem: fix persistence warning
...
Most filesystems currently use mapping_set_error and
filemap_check_errors for setting and reporting/clearing writeback errors
at the mapping level. filemap_check_errors is indirectly called from
most of the filemap_fdatawait_* functions and from
filemap_write_and_wait*. These functions are called from all sorts of
contexts to wait on writeback to finish -- e.g. mostly in fsync, but
also in truncate calls, getattr, etc.
The non-fsync callers are problematic. We should be reporting writeback
errors during fsync, but many places spread over the tree clear out
errors before they can be properly reported, or report errors at
nonsensical times.
If I get -EIO on a stat() call, there is no reason for me to assume that
it is because some previous writeback failed. The fact that it also
clears out the error such that a subsequent fsync returns 0 is a bug,
and a nasty one since that's potentially silent data corruption.
This patch adds a small bit of new infrastructure for setting and
reporting errors during address_space writeback. While the above was my
original impetus for adding this, I think it's also the case that
current fsync semantics are just problematic for userland. Most
applications that call fsync do so to ensure that the data they wrote
has hit the backing store.
In the case where there are multiple writers to the file at the same
time, this is really hard to determine. The first one to call fsync will
see any stored error, and the rest get back 0. The processes with open
fds may not be associated with one another in any way. They could even
be in different containers, so ensuring coordination between all fsync
callers is not really an option.
One way to remedy this would be to track what file descriptor was used
to dirty the file, but that's rather cumbersome and would likely be
slow. However, there is a simpler way to improve the semantics here
without incurring too much overhead.
This set adds an errseq_t to struct address_space, and a corresponding
one is added to struct file. Writeback errors are recorded in the
mapping's errseq_t, and the one in struct file is used as the "since"
value.
This changes the semantics of the Linux fsync implementation such that
applications can now use it to determine whether there were any
writeback errors since fsync(fd) was last called (or since the file was
opened in the case of fsync having never been called).
Note that those writeback errors may have occurred when writing data
that was dirtied via an entirely different fd, but that's the case now
with the current mapping_set_error/filemap_check_error infrastructure.
This will at least prevent you from getting a false report of success.
The new behavior is still consistent with the POSIX spec, and is more
reliable for application developers. This patch just adds some basic
infrastructure for doing this, and ensures that the f_wb_err "cursor"
is properly set when a file is opened. Later patches will change the
existing code to use this new infrastructure for reporting errors at
fsync time.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
The dax_flush() operation can be turned into a nop on platforms where
firmware arranges for cpu caches to be flushed on a power-fail event.
The ACPI 6.2 specification defines a mechanism for the platform to
indicate this capability so the kernel can select the proper default.
However, for other platforms, the administrator must toggle this setting
manually.
Given this flush setting is a dax-specific mechanism we advertise it
through a 'dax' attribute group hanging off a host device. For example,
a 'pmem0' block-device gets a 'dax' sysfs-subdirectory with a
'write_cache' attribute to control response to dax cache flush requests.
This is similar to the 'queue/write_cache' attribute that appears under
block devices.
Cc: Jan Kara <jack@suse.cz>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Require all dax-drivers to register a ->copy_from_iter() operation so
that it is clear which dax_operations are optional and which must be
implemented for filesystem-dax to operate.
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Dave Jiang