Commit graph

982,081 commits

Author SHA1 Message Date
Darrick J. Wong
b96cb835e3 xfs: deprecate the V4 format
The V4 filesystem format contains known weaknesses in the on-disk format
that make metadata verification diffiult.  In addition, the format does
not support dates past 2038 and will not be upgraded to do so.  We
should start the process of retiring the old format to close off attack
surfaces and to encourage users to migrate onto V5.

Therefore, make XFS V4 support a configurable option.  For the first
period it will be default Y in case some distributors want to withdraw
support early; for the second period it will be default N so that anyone
who wishes to continue support can do so; and after that, support will
be removed from the kernel.  Dates for these events have been added to
the upstream kernel.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
2020-09-15 20:52:43 -07:00
Darrick J. Wong
d4f2c14cc9 xfs: don't propagate RTINHERIT -> REALTIME when there is no rtdev
While running generic/042 with -drtinherit=1 set in MKFS_OPTIONS, I
observed that the kernel will gladly set the realtime flag on any file
created on the loopback filesystem even though that filesystem doesn't
actually have a realtime device attached.  This leads to verifier
failures and doesn't make any sense, so be smarter about this.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-09-15 20:52:43 -07:00
Darrick J. Wong
fe341eb151 xfs: ensure that fpunch, fcollapse, and finsert operations are aligned to rt extent size
Make sure that any fallocate operation that requires the range to be
block-aligned also checks that the range is aligned to the realtime
extent size.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-09-15 20:52:42 -07:00
Darrick J. Wong
8a569d717e xfs: refactor inode flags propagation code
Hoist the code that propagates di_flags and di_flags2 from a parent to a
new child into separate functions.  No functional changes.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-09-15 20:52:42 -07:00
Darrick J. Wong
2a6ca4baed xfs: make sure the rt allocator doesn't run off the end
There's an overflow bug in the realtime allocator.  If the rt volume is
large enough to handle a single allocation request that is larger than
the maximum bmap extent length and the rt bitmap ends exactly on a
bitmap block boundary, it's possible that the near allocator will try to
check the freeness of a range that extends past the end of the bitmap.
This fails with a corruption error and shuts down the fs.

Therefore, constrain maxlen so that the range scan cannot run off the
end of the rt bitmap.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-09-15 20:52:42 -07:00
Zheng Bin
0f4ec0f157 xfs: Remove unneeded semicolon
Fixes coccicheck warning:

fs/xfs/xfs_icache.c:1214:2-3: Unneeded semicolon

Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:42 -07:00
Darrick J. Wong
5ffce3cc22 xfs: force the log after remapping a synchronous-writes file
Commit 5833112df7 tried to make it so that a remap operation would
force the log out to disk if the filesystem is mounted with mandatory
synchronous writes.  Unfortunately, that commit failed to handle the
case where the inode or the file descriptor require mandatory
synchronous writes.

Refactor the check into into a helper that will look for all three
conditions, and now we can treat reflink just like any other synchronous
write.

Fixes: 5833112df7 ("xfs: reflink should force the log out if mounted with wsync")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-09-15 20:52:42 -07:00
Carlos Maiolino
e01b7eed5d xfs: Convert xfs_attr_sf macros to inline functions
xfs_attr_sf_totsize() requires access to xfs_inode structure, so, once
xfs_attr_shortform_addname() is its only user, move it to xfs_attr.c
instead of playing with more #includes.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:42 -07:00
Carlos Maiolino
c418dbc980 xfs: Use variable-size array for nameval in xfs_attr_sf_entry
nameval is a variable-size array, so, define it as it, and remove all
the -1 magic number subtractions

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:42 -07:00
Carlos Maiolino
47e6cc1000 xfs: Remove typedef xfs_attr_shortform_t
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:42 -07:00
Carlos Maiolino
6337c84466 xfs: remove typedef xfs_attr_sf_entry_t
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:41 -07:00
Carlos Maiolino
8ca79df85b xfs: Remove kmem_zalloc_large()
This patch aims to replace kmem_zalloc_large() with global kernel memory
API. So, all its callers are now using kvzalloc() directly, so kmalloc()
fallsback to vmalloc() automatically.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:41 -07:00
Darrick J. Wong
29887a2271 xfs: enable big timestamps
Enable the big timestamp feature.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:41 -07:00
Darrick J. Wong
06dbf82b04 xfs: trace timestamp limits
Add a couple of tracepoints so that we can check the timestamp limits
being set on inodes and quotas.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:41 -07:00
Darrick J. Wong
4ea1ff3b49 xfs: widen ondisk quota expiration timestamps to handle y2038+
Enable the bigtime feature for quota timers.  We decrease the accuracy
of the timers to ~4s in exchange for being able to set timers up to the
bigtime maximum.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:41 -07:00
Darrick J. Wong
f93e5436f0 xfs: widen ondisk inode timestamps to deal with y2038+
Redesign the ondisk inode timestamps to be a simple unsigned 64-bit
counter of nanoseconds since 14 Dec 1901 (i.e. the minimum time in the
32-bit unix time epoch).  This enables us to handle dates up to 2486,
which solves the y2038 problem.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:41 -07:00
Darrick J. Wong
30e0559921 xfs: redefine xfs_ictimestamp_t
Redefine xfs_ictimestamp_t as a uint64_t typedef in preparation for the
bigtime functionality.  Preserve the legacy structure format so that we
can let the compiler take care of the masking and shifting.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:41 -07:00
Darrick J. Wong
5a0bb066f6 xfs: redefine xfs_timestamp_t
Redefine xfs_timestamp_t as a __be64 typedef in preparation for the
bigtime functionality.  Preserve the legacy structure format so that we
can let the compiler take care of masking and shifting.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:41 -07:00
Darrick J. Wong
88947ea0ba xfs: move xfs_log_dinode_to_disk to the log recovery code
Move this function to xfs_inode_item_recover.c since there's only one
caller of it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:40 -07:00
Darrick J. Wong
9f99c8fe55 xfs: refactor quota timestamp coding
Refactor quota timestamp encoding and decoding into helper functions so
that we can add extra behavior in the next patch.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:40 -07:00
Darrick J. Wong
ccc8e771aa xfs: refactor default quota grace period setting code
Refactor the code that sets the default quota grace period into a helper
function so that we can override the ondisk behavior later.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:40 -07:00
Darrick J. Wong
11d8a91902 xfs: refactor quota expiration timer modification
Define explicit limits on the range of quota grace period expiration
timeouts and refactor the code that modifies the timeouts into helpers
that clamp the values appropriately.  Note that we'll refactor the
default grace period timer separately.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:40 -07:00
Darrick J. Wong
876fdc7c4f xfs: explicitly define inode timestamp range
Formally define the inode timestamp ranges that existing filesystems
support, and switch the vfs timetamp ranges to use it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-09-15 20:52:40 -07:00
Darrick J. Wong
b896a39faa xfs: enable new inode btree counters feature
Enable the new inode btree counters feature.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-15 20:52:40 -07:00
Darrick J. Wong
11f744234f xfs: support inode btree blockcounts in online repair
Add the necessary bits to the online repair code to support logging the
inode btree counters when rebuilding the btrees, and to support fixing
the counters when rebuilding the AGI.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-15 20:52:40 -07:00
Darrick J. Wong
1dbbff029f xfs: support inode btree blockcounts in online scrub
Add the necessary bits to the online scrub code to check the inode btree
counters when enabled.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-15 20:52:40 -07:00
Darrick J. Wong
1ac35f061a xfs: use the finobt block counts to speed up mount times
Now that we have reliable finobt block counts, use them to speed up the
per-AG block reservation calculations at mount time.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-15 20:52:39 -07:00
Darrick J. Wong
2a39946c98 xfs: store inode btree block counts in AGI header
Add a btree block usage counters for both inode btrees to the AGI header
so that we don't have to walk the entire finobt at mount time to create
the per-AG reservations.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-15 20:52:39 -07:00
Christoph Hellwig
26e328759b xfs: reuse _xfs_buf_read for re-reading the superblock
Instead of poking deeply into buffer cache internals when re-reading the
superblock during log recovery just generalize _xfs_buf_read and use it
there.  Note that we don't have to explicitly set up the ops as they
must be set from the initial read.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:39 -07:00
Christoph Hellwig
b3f8e08ca8 xfs: remove xfs_getsb
Merge xfs_getsb into its only caller, and clean that one up a little bit
as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:39 -07:00
Christoph Hellwig
cead0b10f5 xfs: simplify xfs_trans_getsb
Remove the mp argument as this function is only called in transaction
context, and open code xfs_getsb given that the function already accesses
the buffer pointer in the mount point directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:39 -07:00
Christoph Hellwig
22c10589a1 xfs: remove xlog_recover_iodone
The log recovery I/O completion handler does not substancially differ from
the normal one except for the fact that it:

 a) never retries failed writes
 b) can have log items that aren't on the AIL
 c) never has inode/dquot log items attached and thus don't need to
    handle them

Add conditionals for (a) and (b) to the ioend code, while (c) doesn't
need special handling anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:39 -07:00
Christoph Hellwig
55b7d7115f xfs: clear the read/write flags later in xfs_buf_ioend
Clear the flags at the end of xfs_buf_ioend so that they can be used
during the completion.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:39 -07:00
Christoph Hellwig
b840e2ada8 xfs: use xfs_buf_item_relse in xfs_buf_item_done
Reuse xfs_buf_item_relse instead of duplicating it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:39 -07:00
Christoph Hellwig
70796c6b74 xfs: simplify the xfs_buf_ioend_disposition calling convention
Now that all the actual error handling is in a single place,
xfs_buf_ioend_disposition just needs to return true if took ownership of
the buffer, or false if not instead of the tristate.  Also move the
error check back in the caller to optimize for the fast path, and give
the function a better fitting name.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:38 -07:00
Christoph Hellwig
844c9358df xfs: lift the XBF_IOEND_FAIL handling into xfs_buf_ioend_disposition
Keep all the error handling code together.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:38 -07:00
Christoph Hellwig
3cc498845a xfs: remove xfs_buf_ioerror_retry
Merge xfs_buf_ioerror_retry into its only caller to make the resubmission
flow a little easier to follow.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:38 -07:00
Christoph Hellwig
f58d0ea956 xfs: refactor xfs_buf_ioerror_fail_without_retry
xfs_buf_ioerror_fail_without_retry is a somewhat weird function in
that it has two trivial checks that decide the return value, while
the rest implements a ratelimited warning.  Just lift the two checks
into the caller, and give the remainder a suitable name.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:38 -07:00
Christoph Hellwig
6a7584b1d8 xfs: fold xfs_buf_ioend_finish into xfs_ioend
No need to keep a separate helper for this logic.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:38 -07:00
Christoph Hellwig
664ffb8a42 xfs: move the buffer retry logic to xfs_buf.c
Move the buffer retry state machine logic to xfs_buf.c and call it once
from xfs_ioend instead of duplicating it three times for the three kinds
of buffers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:38 -07:00
Christoph Hellwig
23fb5a93c2 xfs: refactor xfs_buf_ioend
Move the log recovery I/O completion handling entirely into the log
recovery code, and re-arrange the normal I/O completion handler flow
to prepare to lifting more logic into common code in the next commits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:38 -07:00
Christoph Hellwig
76b2d32346 xfs: mark xfs_buf_ioend static
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:38 -07:00
Christoph Hellwig
12e164aa1f xfs: refactor the buf ioend disposition code
Handle the no-error case in xfs_buf_iodone_error as well, and to clarify
the code rename the function, use the actual enum type as return value
and then switch on it in the callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:38 -07:00
Marek Behún
e5467b672b dt-bindings: leds: cznic,turris-omnia-leds: fix error in binding
There is a bug in the device tree binding for cznic,turris-omnia-leds
which causes make dt_binding_check to complain.

The reason is that the multi-led property binding's regular expression
does not contain the `@` character, while the example nodes do.

Fix this, and also adjust the maximum address to 'b' as there are 12
LEDs.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Link: https://lore.kernel.org/r/20200915005426.15957-1-marek.behun@nic.cz
Signed-off-by: Rob Herring <robh@kernel.org>
2020-09-15 21:03:07 -06:00
David S. Miller
d5d325eae7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Alexei Starovoitov says:

====================
pull-request: bpf 2020-09-15

The following pull-request contains BPF updates for your *net* tree.

We've added 12 non-merge commits during the last 19 day(s) which contain
a total of 10 files changed, 47 insertions(+), 38 deletions(-).

The main changes are:

1) docs/bpf fixes, from Andrii.

2) ld_abs fix, from Daniel.

3) socket casting helpers fix, from Martin.

4) hash iterator fixes, from Yonghong.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-15 19:26:21 -07:00
Nicholas Piggin
a665eec0a2 powerpc/64s/radix: Fix mm_cpumask trimming race vs kthread_use_mm
Commit 0cef77c779 ("powerpc/64s/radix: flush remote CPUs out of
single-threaded mm_cpumask") added a mechanism to trim the mm_cpumask of
a process under certain conditions. One of the assumptions is that
mm_users would not be incremented via a reference outside the process
context with mmget_not_zero() then go on to kthread_use_mm() via that
reference.

That invariant was broken by io_uring code (see previous sparc64 fix),
but I'll point Fixes: to the original powerpc commit because we are
changing that assumption going forward, so this will make backports
match up.

Fix this by no longer relying on that assumption, but by having each CPU
check the mm is not being used, and clearing their own bit from the mask
only if it hasn't been switched-to by the time the IPI is processed.

This relies on commit 38cf307c1f ("mm: fix kthread_use_mm() vs TLB
invalidate") and ARCH_WANT_IRQS_OFF_ACTIVATE_MM to disable irqs over mm
switch sequences.

Fixes: 0cef77c779 ("powerpc/64s/radix: flush remote CPUs out of single-threaded mm_cpumask")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
Depends-on: 38cf307c1f ("mm: fix kthread_use_mm() vs TLB invalidate")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-5-npiggin@gmail.com
2020-09-16 12:24:37 +10:00
Nicholas Piggin
bafb056ce2 sparc64: remove mm_cpumask clearing to fix kthread_use_mm race
The de facto (and apparently uncommented) standard for using an mm had,
thanks to this code in sparc if nothing else, been that you must have a
reference on mm_users *and that reference must have been obtained with
mmget()*, i.e., from a thread with a reference to mm_users that had used
the mm.

The introduction of mmget_not_zero() in commit d2005e3f41
("userfaultfd: don't pin the user memory in userfaultfd_file_create()")
allowed mm_count holders to aoperate on user mappings asynchronously
from the actual threads using the mm, but they were not to load those
mappings into their TLB (i.e., walking vmas and page tables is okay,
kthread_use_mm() is not).

io_uring 2b188cc1bb ("Add io_uring IO interface") added code which
does a kthread_use_mm() from a mmget_not_zero() refcount.

The problem with this is code which previously assumed mm == current->mm
and mm->mm_users == 1 implies the mm will remain single-threaded at
least until this thread creates another mm_users reference, has now
broken.

arch/sparc/kernel/smp_64.c:

    if (atomic_read(&mm->mm_users) == 1) {
        cpumask_copy(mm_cpumask(mm), cpumask_of(cpu));
        goto local_flush_and_out;
    }

vs fs/io_uring.c

    if (unlikely(!(ctx->flags & IORING_SETUP_SQPOLL) ||
                 !mmget_not_zero(ctx->sqo_mm)))
        return -EFAULT;
    kthread_use_mm(ctx->sqo_mm);

mmget_not_zero() could come in right after the mm_users == 1 test, then
kthread_use_mm() which sets its CPU in the mm_cpumask. That update could
be lost if cpumask_copy() occurs afterward.

I propose we fix this by allowing mmget_not_zero() to be a first-class
reference, and not have this obscure undocumented and unchecked
restriction.

The basic fix for sparc64 is to remove its mm_cpumask clearing code. The
optimisation could be effectively restored by sending IPIs to mm_cpumask
members and having them remove themselves from mm_cpumask. This is more
tricky so I leave it as an exercise for someone with a sparc64 SMP.
powerpc has a (currently similarly broken) example.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-4-npiggin@gmail.com
2020-09-16 12:24:37 +10:00
Nicholas Piggin
66acd46080 powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
powerpc uses IPIs in some situations to switch a kernel thread away
from a lazy tlb mm, which is subject to the TLB flushing race
described in the changelog introducing ARCH_WANT_IRQS_OFF_ACTIVATE_MM.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-3-npiggin@gmail.com
2020-09-16 12:24:37 +10:00
Nicholas Piggin
d53c3dfb23 mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race
Reading and modifying current->mm and current->active_mm and switching
mm should be done with irqs off, to prevent races seeing an intermediate
state.

This is similar to commit 38cf307c1f ("mm: fix kthread_use_mm() vs TLB
invalidate"). At exec-time when the new mm is activated, the old one
should usually be single-threaded and no longer used, unless something
else is holding an mm_users reference (which may be possible).

Absent other mm_users, there is also a race with preemption and lazy tlb
switching. Consider the kernel_execve case where the current thread is
using a lazy tlb active mm:

  call_usermodehelper()
    kernel_execve()
      old_mm = current->mm;
      active_mm = current->active_mm;
      *** preempt *** -------------------->  schedule()
                                               prev->active_mm = NULL;
                                               mmdrop(prev active_mm);
                                             ...
                      <--------------------  schedule()
      current->mm = mm;
      current->active_mm = mm;
      if (!old_mm)
          mmdrop(active_mm);

If we switch back to the kernel thread from a different mm, there is a
double free of the old active_mm, and a missing free of the new one.

Closing this race only requires interrupts to be disabled while ->mm
and ->active_mm are being switched, but the TLB problem requires also
holding interrupts off over activate_mm. Unfortunately not all archs
can do that yet, e.g., arm defers the switch if irqs are disabled and
expects finish_arch_post_lock_switch() to be called to complete the
flush; um takes a blocking lock in activate_mm().

So as a first step, disable interrupts across the mm/active_mm updates
to close the lazy tlb preempt race, and provide an arch option to
extend that to activate_mm which allows architectures doing IPI based
TLB shootdowns to close the second race.

This is a bit ugly, but in the interest of fixing the bug and backporting
before all architectures are converted this is a compromise.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-2-npiggin@gmail.com
2020-09-16 12:24:31 +10:00
Ming Lei
ed5dd6a67d scsi: core: Only re-run queue in scsi_end_request() if device queue is busy
The request queue is currently run unconditionally in scsi_end_request() if
both target queue and host queue are ready.

Recently Long Li reported that cost of a queue run can be very heavy in
case of high queue depth. Improve this situation by only running the
request queue when this LUN is busy.

Link: https://lore.kernel.org/r/20200910075056.36509-1-ming.lei@redhat.com
Reported-by: Long Li <longli@microsoft.com>
Tested-by: Long Li <longli@microsoft.com>
Tested-by: Kashyap Desai <kashyap.desai@broadcom.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2020-09-15 22:20:11 -04:00