Hole puching currently evicts pages from page cache and then goes on to
remove blocks from the inode. This happens under both XFS_IOLOCK_EXCL
and XFS_MMAPLOCK_EXCL which provides appropriate serialization with
racing reads or page faults. However there is currently nothing that
prevents readahead triggered by fadvise() or madvise() from racing with
the hole punch and instantiating page cache page after hole punching has
evicted page cache in xfs_flush_unmap_range() but before it has removed
blocks from the inode. This page cache page will be mapping soon to be
freed block and that can lead to returning stale data to userspace or
even filesystem corruption.

Fix the problem by protecting handling of readahead requests by
XFS_IOLOCK_SHARED similarly as we protect reads.

CC: stable@vger.kernel.org
Link: https://lore.kernel.org/linux-fsdevel/CAOQ4uxjQNmxqmtA_VbYW0Su9rKRk2zobJmahcyeaEVOFKVQ5dw@mail.gmail.com/Reported-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Filesystems will need to call this function from their fadvise handlers.

CC: stable@vger.kernel.org
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Currently handling of MADV_WILLNEED hint calls directly into readahead
code. Handle it by calling vfs_fadvise() instead so that filesystem can
use its ->fadvise() callback to acquire necessary locks or otherwise
prepare for the request.
Suggested-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Boaz Harrosh <boazh@netapp.com>
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

When doing file lookups and checking for permissions, we end up in
xfs_get_acl() to see if there are any ACLs on the inode. This
requires and xattr lookup, and to do that we have to supply a buffer
large enough to hold an maximum sized xattr.

On workloads were we are accessing a wide range of cache cold files
under memory pressure (e.g. NFS fileservers) we end up spending a
lot of time allocating the buffer. The buffer is 64k in length, so
is a contiguous multi-page allocation, and if that then fails we
fall back to vmalloc(). Hence the allocation here is /expensive/
when we are looking up hundreds of thousands of files a second.

Initial numbers from a bpf trace show average time in xfs_get_acl()
is ~32us, with ~19us of that in the memory allocation. Note these
are average times, so there are going to be affected by the worst
case allocations more than the common fast case...

To avoid this, we could just do a "null"  lookup to see if the ACL
xattr exists and then only do the allocation if it exists. This,
however, optimises the path for the "no ACL present" case at the
expense of the "acl present" case. i.e. we can halve the time in
xfs_get_acl() for the no acl case (i.e down to ~10-15us), but that
then increases the ACL case by 30% (i.e. up to 40-45us).

To solve this and speed up both cases, drive the xattr buffer
allocation into the attribute code once we know what the actual
xattr length is. For the no-xattr case, we avoid the allocation
completely, speeding up that case. For the common ACL case, we'll
end up with a fast heap allocation (because it'll be smaller than a
page), and only for the rarer "we have a remote xattr" will we have
a multi-page allocation occur. Hence the common ACL case will be
much faster, too.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

The same code is used to copy do the attribute copying in three
different places. Consolidate them into a single function in
preparation from on-demand buffer allocation.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

Because we repeat exactly the same code to get the remote attribute
value after both calls to xfs_attr3_leaf_getvalue() if it's a remote
attr. Just do it in xfs_attr3_leaf_getvalue() so the callers don't
have to care about it.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

Shortform, leaf and remote value attr value retrieval return
different values for success. This makes it more complex to handle
actual errors xfs_attr_get() as some errors mean success and some
mean failure. Make the return values consistent for success and
failure consistent for all attribute formats.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

When a directory is growing rapidly, new blocks tend to get added at
the end of the directory. These end up at the end of the freespace
index, and when the directory gets large finding these new
freespaces gets expensive. The code does a linear search across the
frespace index from the first block in the directory to the last,
hence meaning the newly added space is the last index searched.

Instead, do a reverse order index search, starting from the last
block and index in the freespace index. This makes most lookups for
free space on rapidly growing directories O(1) instead of O(N), but
should not have any impact on random insert workloads because the
average search length is the same regardless of which end of the
array we start at.

The result is a major improvement in large directory grow rates:

		create time(sec) / rate (files/s)
 File count     vanilla             Prev commit		Patched
  10k	      0.41 / 24.3k	   0.42 / 23.8k       0.41 / 24.3k
  20k	      0.74 / 27.0k	   0.76 / 26.3k       0.75 / 26.7k
 100k	      3.81 / 26.4k	   3.47 / 28.8k       3.27 / 30.6k
 200k	      8.58 / 23.3k	   7.19 / 27.8k       6.71 / 29.8k
   1M	     85.69 / 11.7k	  48.53 / 20.6k      37.67 / 26.5k
   2M	    280.31 /  7.1k	 130.14 / 15.3k      79.55 / 25.2k
  10M	   3913.26 /  2.5k                          552.89 / 18.1k
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

When running a "create millions inodes in a directory" test
recently, I noticed we were spending a huge amount of time
converting freespace block headers from disk format to in-memory
format:

 31.47%  [kernel]  [k] xfs_dir2_node_addname
 17.86%  [kernel]  [k] xfs_dir3_free_hdr_from_disk
  3.55%  [kernel]  [k] xfs_dir3_free_bests_p

We shouldn't be hitting the best free block scanning code so hard
when doing sequential directory creates, and it turns out there's
a highly suboptimal loop searching the the best free array in
the freespace block - it decodes the block header before checking
each entry inside a loop, instead of decoding the header once before
running the entry search loop.

This makes a massive difference to create rates. Profile now looks
like this:

  13.15%  [kernel]  [k] xfs_dir2_node_addname
   3.52%  [kernel]  [k] xfs_dir3_leaf_check_int
   3.11%  [kernel]  [k] xfs_log_commit_cil

And the wall time/average file create rate differences are
just as stark:

		create time(sec) / rate (files/s)
File count	     vanilla		    patched
  10k		   0.41 / 24.3k		   0.42 / 23.8k
  20k		   0.74	/ 27.0k		   0.76 / 26.3k
 100k		   3.81	/ 26.4k		   3.47 / 28.8k
 200k		   8.58	/ 23.3k		   7.19 / 27.8k
   1M		  85.69	/ 11.7k		  48.53 / 20.6k
   2M		 280.31	/  7.1k		 130.14 / 15.3k

The larger the directory, the bigger the performance improvement.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

Simplify the logic in xfs_dir2_node_addname_int() by factoring out
the free block index lookup code that finds a block with enough free
space for the entry to be added. The code that is moved gets a major
cleanup at the same time, but there is no algorithm change here.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

Factor out the code that adds a data block to a directory from
xfs_dir2_node_addname_int(). This makes the code flow cleaner and
more obvious and provides clear isolation of upcoming optimsations.
Signed-off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

This gets rid of the need for a forward  declaration of the static
function xfs_dir2_addname_int() and readies the code for factoring
of xfs_dir2_addname_int().
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

Iterator functions already use 0 to signal "continue iterating", so get
rid of the #defines and just do it directly.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Use -ECANCELED to signal "stop iterating" instead of these magical
*_ITER_ABORT values, since it's duplicative.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs_trans_log_buf() takes a final argument of the last byte to
log in the buffer; b_length is in basic blocks, so this isn't
the correct last byte.  Fix it.
Signed-off-by: Eric Sandeen <sandeen@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>

In xfs_rmap_irec_offset_unpack, we should always clear the contents of
rm_flags before we begin unpacking the encoded (ondisk) offset into the
incore rm_offset and incore rm_flags fields.  Remove the open-coded
field zeroing as this encourages api misuse.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Remove the return value from the functions that schedule deferred bmap
operations since they never fail and do not return status.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Remove the return value from the functions that schedule deferred
refcount operations since they never fail and do not return status.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Remove the return value from the functions that schedule deferred rmap
operations since they never fail and do not return status.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

This function doesn't use the @state parameter, so get rid of it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

In xfs_bmbt_diff_two_keys, we perform a signed int64_t subtraction with
two unsigned 64-bit quantities.  If the second quantity is actually the
"maximum" key (all ones) as used in _query_all, the subtraction
effectively becomes addition of two positive numbers and the function
returns incorrect results.  Fix this with explicit comparisons of the
unsigned values.  Nobody needs this now, but the online repair patches
will need this to work properly.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

The xfs_rmap_has_other_keys helper aborts the iteration as soon as it
has an answer.  Don't let this abort leak out to callers.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

In xfs_ialloc_setup_geometry, it's possible for a malicious/corrupt fs
image to set an unreasonably large value for sb_inopblog which will
cause ialloc_blks to be zero.  If sb_imax_pct is also set, this results
in a division by zero error in the second do_div call.  Therefore, force
maxicount to zero if ialloc_blks is zero.

Note that the kernel metadata verifiers will catch the garbage inopblog
value and abort the fs mount long before it tries to set up the inode
geometry; this is needed to avoid a crash in xfs_db while setting up the
xfs_mount structure.

Found by fuzzing sb_inopblog to 122 in xfs/350.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>

The inode block mapping scrub function does more work for btree format
extent maps than is absolutely necessary -- first it will walk the bmbt
and check all the entries, and then it will load the incore tree and
check every entry in that tree, possibly for a second time.

Simplify the code and decrease check runtime by separating the two
responsibilities.  The bmbt walk will make sure the incore extent
mappings are loaded, check the shape of the bmap btree (via xchk_btree)
and check that every bmbt record has a corresponding incore extent map;
and the incore extent map walk takes all the responsibility for checking
the mapping records and cross referencing them with other AG metadata.

This enables us to clean up some messy parameter handling and reduce
redundant code.  Rename a few functions to make the split of
responsibilities clearer.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

Fixes gcc warning:

fs/xfs/libxfs/xfs_btree.c:4475: warning: Excess function parameter 'max_recs' description in 'xfs_btree_sblock_v5hdr_verify'
fs/xfs/libxfs/xfs_btree.c:4475: warning: Excess function parameter 'pag_max_level' description in 'xfs_btree_sblock_v5hdr_verify'

Fixes: c5ab131b ("libxfs: refactor short btree block verification")
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Memory we use to submit for IO needs strict alignment to the
underlying driver contraints. Worst case, this is 512 bytes. Given
that all allocations for IO are always a power of 2 multiple of 512
bytes, the kernel heap provides natural alignment for objects of
these sizes and that suffices.

Until, of course, memory debugging of some kind is turned on (e.g.
red zones, poisoning, KASAN) and then the alignment of the heap
objects is thrown out the window. Then we get weird IO errors and
data corruption problems because drivers don't validate alignment
and do the wrong thing when passed unaligned memory buffers in bios.

TO fix this, introduce kmem_alloc_io(), which will guaranteeat least
512 byte alignment of buffers for IO, even if memory debugging
options are turned on. It is assumed that the minimum allocation
size will be 512 bytes, and that sizes will be power of 2 mulitples
of 512 bytes.

Use this everywhere we allocate buffers for IO.

This no longer fails with log recovery errors when KASAN is enabled
due to the brd driver not handling unaligned memory buffers:

# mkfs.xfs -f /dev/ram0 ; mount /dev/ram0 /mnt/test
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

Needed to feed into the allocation routine to guarantee the memory
buffers we add to bios are correctly aligned to the underlying
device.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-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>

When trying to correlate XFS kernel allocations to memory reclaim
behaviour, it is useful to know what allocations XFS is actually
attempting. This information is not directly available from
tracepoints in the generic memory allocation and reclaim
tracepoints, so these new trace points provide a high level
indication of what the XFS memory demand actually is.

There is no per-filesystem context in this code, so we just trace
the type of allocation, the size and the allocation constraints.
The kmem code also doesn't include much of the common XFS headers,
so there are a few definitions that need to be added to the trace
headers and a couple of types that need to be made common to avoid
needing to include the whole world in the kmem code.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-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>

Since no caller is using KM_NOSLEEP and no callee branches on KM_SLEEP,
we can remove KM_NOSLEEP and replace KM_SLEEP with 0.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Pull auxdisplay cleanup from Miguel Ojeda:
 "Make ht16k33_fb_fix and ht16k33_fb_var constant (Nishka Dasgupta)"

* tag 'auxdisplay-for-linus-v5.3-rc7' of git://github.com/ojeda/linux:
  auxdisplay: ht16k33: Make ht16k33_fb_fix and ht16k33_fb_var constant

Pull UML fix from Richard Weinberger:
 "Fix time travel mode"

* tag 'for-linus-5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: fix time travel mode

Pull UBIFS and JFFS2 fixes from Richard Weinberger:
 "UBIFS:
   - Don't block too long in writeback_inodes_sb()
   - Fix for a possible overrun of the log head
   - Fix double unlock in orphan_delete()

  JFFS2:
   - Remove C++ style from UAPI header and unbreak picky toolchains"

* tag 'for-linus-5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs:
  ubifs: Limit the number of pages in shrink_liability
  ubifs: Correctly initialize c->min_log_bytes
  ubifs: Fix double unlock around orphan_delete()
  jffs2: Remove C++ style comments from uapi header

Pull x86 fixes from Thomas Gleixner:
 "A few fixes for x86:

   - Fix a boot regression caused by the recent bootparam sanitizing
     change, which escaped the attention of all people who reviewed that
     code.

   - Address a boot problem on machines with broken E820 tables caused
     by an underflow which ended up placing the trampoline start at
     physical address 0.

   - Handle machines which do not advertise a legacy timer of any form,
     but need calibration of the local APIC timer gracefully by making
     the calibration routine independent from the tick interrupt. Marked
     for stable as well as there seems to be quite some new laptops
     rolled out which expose this.

   - Clear the RDRAND CPUID bit on AMD family 15h and 16h CPUs which are
     affected by broken firmware which does not initialize RDRAND
     correctly after resume. Add a command line parameter to override
     this for machine which either do not use suspend/resume or have a
     fixed BIOS. Unfortunately there is no way to detect this on boot,
     so the only safe decision is to turn it off by default.

   - Prevent RFLAGS from being clobbers in CALL_NOSPEC on 32bit which
     caused fast KVM instruction emulation to break.

   - Explain the Intel CPU model naming convention so that the repeating
     discussions come to an end"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/retpoline: Don't clobber RFLAGS during CALL_NOSPEC on i386
  x86/boot: Fix boot regression caused by bootparam sanitizing
  x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h
  x86/boot/compressed/64: Fix boot on machines with broken E820 table
  x86/apic: Handle missing global clockevent gracefully
  x86/cpu: Explain Intel model naming convention

Pull timekeeping fix from Thomas Gleixner:
 "A single fix for a regression caused by the generic VDSO
  implementation where a math overflow causes CLOCK_BOOTTIME to become a
  random number generator"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping/vsyscall: Prevent math overflow in BOOTTIME update

Pull scheduler fix from Thomas Gleixner:
 "Handle the worker management in situations where a task is scheduled
  out on a PI lock contention correctly and schedule a new worker if
  possible"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Schedule new worker even if PI-blocked

Pull perf fixes from Thomas Gleixner:
 "Two small fixes for kprobes and perf:

   - Prevent a deadlock in kprobe_optimizer() causes by reverse lock
     ordering

   - Fix a comment typo"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kprobes: Fix potential deadlock in kprobe_optimizer()
  perf/x86: Fix typo in comment

Pull irq fix from Thomas Gleixner:
 "A single fix for a imbalanced kobject operation in the irq decriptor
  code which was unearthed by the new warnings in the kobject code"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Properly pair kobject_del() with kobject_add()

Mergr misc fixes from Andrew Morton:
 "11 fixes"

Mostly VM fixes, one psi polling fix, and one parisc build fix.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/kasan: fix false positive invalid-free reports with CONFIG_KASAN_SW_TAGS=y
  mm/zsmalloc.c: fix race condition in zs_destroy_pool
  mm/zsmalloc.c: migration can leave pages in ZS_EMPTY indefinitely
  mm, page_owner: handle THP splits correctly
  userfaultfd_release: always remove uffd flags and clear vm_userfaultfd_ctx
  psi: get poll_work to run when calling poll syscall next time
  mm: memcontrol: flush percpu vmevents before releasing memcg
  mm: memcontrol: flush percpu vmstats before releasing memcg
  parisc: fix compilation errrors
  mm, page_alloc: move_freepages should not examine struct page of reserved memory
  mm/z3fold.c: fix race between migration and destruction