The heuristic for readdirplus is designed to try to detect 'ls -l' and
similar patterns. It does so by looking for cache hit/miss patterns in
both the attribute cache and in the dcache of the files in a given
directory, and then sets a flag for the readdirplus code to interpret.

The problem with this approach is that a single attribute or dcache miss
can cause the NFS code to force a refresh of the attributes for the
entire set of files contained in the directory.

To be able to make a more nuanced decision, let's sample the number of
hits and misses in the set of open directory descriptors. That allows us
to set thresholds at which we start preferring READDIRPLUS over regular
READDIR, or at which we start to force a re-read of the remaining
readdir cache using READDIRPLUS.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

When reading a very large directory, we want to try to keep the page
cache up to date if doing so is inexpensive. With the change to allow
readdir to continue reading even when the cache is incomplete, we no
longer need to fall back to uncached readdir in order to scale to large
directories.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Recent changes to readdir mean that we can cope with partially filled
page cache entries, so we no longer need to rely on looping in
nfs_readdir_xdr_to_array().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that if the cookie verifier changes when we use the zero-valued
cookie, then we invalidate any cached pages.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

The current NFS readdir code will always try to maximise the amount of
readahead it performs on the assumption that we can cache anything that
isn't immediately read by the process.
There are several cases where this assumption breaks down, including
when the 'ls -l' heuristic kicks in to try to force use of readdirplus
as a batch replacement for lookup/getattr.

This patch therefore tries to tone down the amount of readahead we
perform, and adjust it to try to match the amount of data being
requested by user space.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

When we hit the end of the data in the readdir page, we don't want to
start filling a new page, unless this one is full.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If the page cache entry that was last read gets invalidated for some
reason, then make sure we can re-create it on the next call to readdir.
This, combined with the cache page validation, allows us to reuse the
cached value of page-index on successive calls to nfs_readdir.

Credit is due to Benjamin Coddington for showing that the concept works,
and that it allows for improved cache sharing between processes even in
the case where pages are lost due to LRU or active invalidation.
Suggested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Use the change attribute and the first cookie in a directory page cache
entry to validate that the page is up to date.
Suggested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Instead of relying on counting the page offsets as we walk through the
page cache, switch to calculating them algorithmically.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

For the purpose of ensuring that opendir() followed by seekdir() work as
correctly as possible, try to initialise the readdir verifier in
nfs_opendir().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Enable tracing of lookup revalidation failures.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Valid return values for decode_dirent() callback functions are:
 0: Success
 -EBADCOOKIE: End of directory
 -EAGAIN: End of xdr_stream

All errors need to map into one of those three values.

Fixes: 573c4e1e ("NFS: Simplify ->decode_dirent() calling sequence")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

This reverts commit 50c790a0.

The functionality is believed to be capable of causing regressions in
existing setups, so the author has requested that it be reverted.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

The use of mapping_set_error() in conjunction with calls to
filemap_check_errors() is problematic because every error gets reported
as either an EIO or an ENOSPC by filemap_check_errors() in functions
such as filemap_write_and_wait() or filemap_write_and_wait_range().
In almost all cases, we prefer to use the more nuanced wb errors.

Fixes: b8946d7b ("NFS: Revalidate the file mapping on all fatal writeback errors")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Add a helper for the xattr mask so that we can get rid of the inlined
ifdefs.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We should never expect the 'xattr_cache' to be non-null in that case,
hence nfs_set_cache_invalid() is just going to optimise it away.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that we always initialise the 'xattr_support' field in struct
nfs_fsinfo, so that nfs_server_set_fsinfo() doesn't declare our NFSv2/v3
client to be capable of supporting the NFSv4.2 xattr protocol by setting
the NFS_CAP_XATTR capability.

This configuration can cause nfs_do_access() to set access mode bits
that are unsupported by the NFSv3 ACCESS call, which may confuse
spec-compliant servers.
Reported-by: Olga Kornievskaia <kolga@netapp.com>
Fixes: b78ef845 ("NFSv4.2: query the server for extended attribute support")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Now that we have more fine grained attribute revalidation, let's just
get rid of NFS_INO_REVAL_PAGECACHE.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

In order to differentiate client state, assign a random uuid to the
uniquifing portion of the client identifier when a network namespace is
created.  Containers may still override this value if they wish to maintain
stable client identifiers by writing to /sys/fs/nfs/net/client/identifier,
either by udev rules or other means.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

In 4.1+, the server is allowed to set a flag
NFS4_RESULT_PRESERVE_UNLINKED in reply to the OPEN, that tells
the client that it does not need to do a silly rename of an
opened file when it's being removed.
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Assume that the upper layers have set memalloc_nofs_save/restore as
appropriate.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Assume that the upper layers have set memalloc_nofs_save/restore as
appropriate.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

The sections which should not re-enter the filesystem are already
protected with memalloc_nofs_save/restore calls, so it is better to use
GFP_KERNEL in these calls to allow better performance for synchronous
RPC calls.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

There doesn't seem to be any reason why the copy offload code can't use
GFP_KERNEL. It can't get called by direct reclaim.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Assume that the higher layers will have set memalloc_nofs_save/restore
as appropriate.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Assume that sections that should not re-enter the filesystem are already
protected with memalloc_nofs_save/restore call, so relax those GFP_NOFS
instances which might be used by other contexts.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We should use either GFP_KERNEL or GFP_NOFS, but not both. Also strip
GFP_KERNEL_ACCOUNT down to GFP_KERNEL. This memory is shrinkable, so
does not need to be limited by kmemcg.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Allow kmemcg to limit the number of NFSv4 delegation, lock and open
state trackers.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Allow kmemcg to limit the number of open/lock file contexts, in the same
way that it limits the parent file descriptors.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If memory allocation triggers a direct reclaim from the state recovery
thread, then we can deadlock. Use memalloc_nofs_save/restore to ensure
that doesn't happen.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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Pointer plainhdr is being assigned a value that is never read, the
pointer is redundant and can be removed.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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The reference counting issue happens in two error paths in the
function _nfs42_proc_copy_notify(). In both error paths, the function
simply returns the error code and forgets to balance the refcount of
object `ctx`, bumped by get_nfs_open_context() earlier, which may
cause refcount leaks.

Fix it by balancing refcount of the `ctx` object before the function
returns in both error paths.
Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS is one of the last two users of the deprecated ->readpages aop.
This conversion looks straightforward, but I have only compile-tested
it.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

nfs42_files_from_same_server() is called to check if freeing
cn_resp is required, just do the free.
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Pull clk fixes from Stephen Boyd:
 "A couple driver fixes in the clk subsystem

   - Fix a hang due to bad clk parent in the Ingenic jz4725b driver

   - Fix SD controllers on Qualcomm MSM8994 SoCs by removing clks that
     shouldn't be touched"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: jz4725b: fix mmc0 clock gating
  clk: qcom: gcc-msm8994: Remove NoC clocks

Pull drm fixes from Dave Airlie:
 "Regular drm fixes pull, i915, amdgpu and tegra mostly, all pretty
  small.

  core:
   - edid: Always set RGB444

  tegra:
   - tegra186 suspend/resume fixes
   - syncpoint wait fix
   - build warning fix
   - eDP on older devices fix

  amdgpu:
   - Display FP fix
   - PCO powergating fix
   - RDNA2 OEM SKU stability fixes
   - Display PSR fix
   - PCI ASPM fix
   - Display link encoder fix for TEST_COMMIT
   - Raven2 suspend/resume fix
   - Fix a regression in virtual display support
   - GPUVM eviction fix

  i915:
   - Fix QGV handling on ADL-P+
   - Fix bw atomic check when switching between SAGV vs. no SAGV
   - Disconnect PHYs left connected by BIOS on disabled ports
   - Fix SAVG to no SAGV transitions on TGL+
   - Print PHY name properly on calibration error (DG2)

  imx:
   - dcss: Select GEM CMA helpers

  radeon:
   - Fix some variables's type

  vc4:
   - Fix codec cleanup
   - Fix PM reference counting"

* tag 'drm-fixes-2022-02-25' of git://anongit.freedesktop.org/drm/drm: (24 commits)
  drm/amdgpu: check vm ready by amdgpu_vm->evicting flag
  drm/amdgpu: bypass tiling flag check in virtual display case (v2)
  Revert "drm/amdgpu: add modifiers in amdgpu_vkms_plane_init()"
  drm/amdgpu: do not enable asic reset for raven2
  drm/amd/display: Fix stream->link_enc unassigned during stream removal
  drm/amd: Check if ASPM is enabled from PCIe subsystem
  drm/edid: Always set RGB444
  drm/tegra: dpaux: Populate AUX bus
  drm/radeon: fix variable type
  drm/amd/display: For vblank_disable_immediate, check PSR is really used
  drm/amd/pm: fix some OEM SKU specific stability issues
  drm/amdgpu: disable MMHUB PG for Picasso
  drm/amd/display: Protect update_bw_bounding_box FPU code.
  drm/i915/dg2: Print PHY name properly on calibration error
  drm/i915: Fix bw atomic check when switching between SAGV vs. no SAGV
  drm/i915: Correctly populate use_sagv_wm for all pipes
  drm/i915: Disconnect PHYs left connected by BIOS on disabled ports
  drm/i915: Widen the QGV point mask
  drm/imx/dcss: i.MX8MQ DCSS select DRM_GEM_CMA_HELPER
  drm/vc4: crtc: Fix runtime_pm reference counting
  ...

Merge tag 'perf-tools-fixes-for-v5.17-2022-02-24' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

Pull perf tools fixes from Arnaldo Carvalho de Melo:

 - Fix double free in in the error path when opening perf.data from
   multiple files in a directory instead of from a single file

 - Sync the msr-index.h copy with the kernel sources

 - Fix error when printing 'weight' field in 'perf script'

 - Skip failing sigtrap test for arm+aarch64 in 'perf test'

 - Fix failure to use a cpu list for uncore events in hybrid systems,
   e.g. Intel Alder Lake

* tag 'perf-tools-fixes-for-v5.17-2022-02-24' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
  perf script: Fix error when printing 'weight' field
  tools arch x86: Sync the msr-index.h copy with the kernel sources
  perf data: Fix double free in perf_session__delete()
  perf evlist: Fix failed to use cpu list for uncore events
  perf test: Skip failing sigtrap test for arm+aarch64