Merge tag 'vfs-6.14-rc1.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs netfs updates from Christian Brauner:
"This contains read performance improvements and support for m

Merge tag 'vfs-6.14-rc1.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs netfs updates from Christian Brauner:
"This contains read performance improvements and support for monolithic
single-blob objects that have to be read/written as such (e.g. AFS
directory contents). The implementation of the two parts is interwoven
as each makes the other possible.

- Read performance improvements

The read performance improvements are intended to speed up some
loss of performance detected in cifs and to a lesser extend in afs.

The problem is that we queue too many work items during the
collection of read results: each individual subrequest is collected
by its own work item, and then they have to interact with each
other when a series of subrequests don't exactly align with the
pattern of folios that are being read by the overall request.

Whilst the processing of the pages covered by individual
subrequests as they complete potentially allows folios to be woken
in parallel and with minimum delay, it can shuffle wakeups for
sequential reads out of order - and that is the most common I/O
pattern.

The final assessment and cleanup of an operation is then held up
until the last I/O completes - and for a synchronous sequential
operation, this means the bouncing around of work items just adds
latency.

Two changes have been made to make this work:

(1) All collection is now done in a single "work item" that works
progressively through the subrequests as they complete (and
also dispatches retries as necessary).

(2) For readahead and AIO, this work item be done on a workqueue
and can run in parallel with the ultimate consumer of the data;
for synchronous direct or unbuffered reads, the collection is
run in the application thread and not offloaded.

Functions such as smb2_readv_callback() then just tell netfslib
that the subrequest has terminated; netfslib does a minimal bit of
processing on the spot - stat counting and tracing mostly - and
then queues/wakes up the worker. This simplifies the logic as the
collector just walks sequentially through the subrequests as they
complete and walks through the folios, if buffered, unlocking them
as it goes. It also keeps to a minimum the amount of latency
injected into the filesystem's low-level I/O handling

The way netfs supports filesystems using the deprecated
PG_private_2 flag is changed: folios are flagged and added to a
write request as they complete and that takes care of scheduling
the writes to the cache. The originating read request can then just
unlock the pages whatever happens.

- Single-blob object support

Single-blob objects are files for which the content of the file
must be read from or written to the server in a single operation
because reading them in parts may yield inconsistent results. AFS
directories are an example of this as there exists the possibility
that the contents are generated on the fly and would differ between
reads or might change due to third party interference.

Such objects will be written to and retrieved from the cache if one
is present, though we allow/may need to propose multiple
subrequests to do so. The important part is that read from/write to
the *server* is monolithic.

Single blob reading is, for the moment, fully synchronous and does
result collection in the application thread and, also for the
moment, the API is supplied the buffer in the form of a folio_queue
chain rather than using the pagecache.

- Related afs changes

This series makes a number of changes to the kafs filesystem,
primarily in the area of directory handling:

- AFS's FetchData RPC reply processing is made partially
asynchronous which allows the netfs_io_request's outstanding
operation counter to be removed as part of reducing the
collection to a single work item.

- Directory and symlink reading are plumbed through netfslib using
the single-blob object API and are now cacheable with fscache.
This also allows the afs_read struct to be eliminated and
netfs_io_subrequest to be used directly instead.

- Directory and symlink content are now stored in a folio_queue
buffer rather than in the pagecache. This means we don't require
the RCU read lock and xarray iteration to access it, and folios
won't randomly disappear under us because the VM wants them
back.

- The vnode operation lock is changed from a mutex struct to a
private lock implementation. The problem is that the lock now
needs to be dropped in a separate thread and mutexes don't
permit that.

- When a new directory or symlink is created, we now initialise it
locally and mark it valid rather than downloading it (we know
what it's likely to look like).

- We now use the in-directory hashtable to reduce the number of
entries we need to scan when doing a lookup. The edit routines
have to maintain the hash chains.

- Cancellation (e.g. by signal) of an async call after the
rxrpc_call has been set up is now offloaded to the worker thread
as there will be a notification from rxrpc upon completion. This
avoids a double cleanup.

- A "rolling buffer" implementation is created to abstract out the
two separate folio_queue chaining implementations I had (one for
read and one for write).

- Functions are provided to create/extend a buffer in a folio_queue
chain and tear it down again.

This is used to handle AFS directories, but could also be used to
create bounce buffers for content crypto and transport crypto.

- The was_async argument is dropped from netfs_read_subreq_terminated()

Instead we wake the read collection work item by either queuing it
or waking up the app thread.

- We don't need to use BH-excluding locks when communicating between
the issuing thread and the collection thread as neither of them now
run in BH context.

- Also included are a number of new tracepoints; a split of the
netfslib write collection code to put retrying into its own file
(it gets more complicated with content encryption).

- There are also some minor fixes AFS included, including fixing the
AFS directory format struct layout, reducing some directory
over-invalidation and making afs_mkdir() translate EEXIST to
ENOTEMPY (which is not available on all systems the servers
support).

- Finally, there's a patch to try and detect entry into the folio
unlock function with no folio_queue structs in the buffer (which
isn't allowed in the cases that can get there).

This is a debugging patch, but should be minimal overhead"

* tag 'vfs-6.14-rc1.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (31 commits)
netfs: Report on NULL folioq in netfs_writeback_unlock_folios()
afs: Add a tracepoint for afs_read_receive()
afs: Locally initialise the contents of a new symlink on creation
afs: Use the contained hashtable to search a directory
afs: Make afs_mkdir() locally initialise a new directory's content
netfs: Change the read result collector to only use one work item
afs: Make {Y,}FS.FetchData an asynchronous operation
afs: Fix cleanup of immediately failed async calls
afs: Eliminate afs_read
afs: Use netfslib for symlinks, allowing them to be cached
afs: Use netfslib for directories
afs: Make afs_init_request() get a key if not given a file
netfs: Add support for caching single monolithic objects such as AFS dirs
netfs: Add functions to build/clean a buffer in a folio_queue
afs: Add more tracepoints to do with tracking validity
cachefiles: Add auxiliary data trace
cachefiles: Add some subrequest tracepoints
netfs: Remove some extraneous directory invalidations
afs: Fix directory format encoding struct
afs: Fix EEXIST error returned from afs_rmdir() to be ENOTEMPTY
...

show more ...

Merge patch series "netfs: Read performance improvements and "single-blob" support"

David Howells <dhowells@redhat.com> says:

This set of patches is primarily about two things: improving read
perfo

Merge patch series "netfs: Read performance improvements and "single-blob" support"

David Howells <dhowells@redhat.com> says:

This set of patches is primarily about two things: improving read
performance and supporting monolithic single-blob objects that have to be
read/written as such (e.g. AFS directory contents). The implementation of
the two parts is interwoven as each makes the other possible.

READ PERFORMANCE
================

The read performance improvements are intended to speed up some loss of
performance detected in cifs and to a lesser extend in afs. The problem is
that we queue too many work items during the collection of read results:
each individual subrequest is collected by its own work item, and then they
have to interact with each other when a series of subrequests don't exactly
align with the pattern of folios that are being read by the overall
request.

Whilst the processing of the pages covered by individual subrequests as
they complete potentially allows folios to be woken in parallel and with
minimum delay, it can shuffle wakeups for sequential reads out of order -
and that is the most common I/O pattern.

The final assessment and cleanup of an operation is then held up until the
last I/O completes - and for a synchronous sequential operation, this means
the bouncing around of work items just adds latency.

Two changes have been made to make this work:

(1) All collection is now done in a single "work item" that works
progressively through the subrequests as they complete (and also
dispatches retries as necessary).

(2) For readahead and AIO, this work item be done on a workqueue and can
run in parallel with the ultimate consumer of the data; for
synchronous direct or unbuffered reads, the collection is run in the
application thread and not offloaded.

Functions such as smb2_readv_callback() then just tell netfslib that the
subrequest has terminated; netfslib does a minimal bit of processing on the
spot - stat counting and tracing mostly - and then queues/wakes up the
worker. This simplifies the logic as the collector just walks sequentially
through the subrequests as they complete and walks through the folios, if
buffered, unlocking them as it goes. It also keeps to a minimum the amount
of latency injected into the filesystem's low-level I/O handling

The way netfs supports filesystems using the deprecated PG_private_2 flag
is changed: folios are flagged and added to a write request as they
complete and that takes care of scheduling the writes to the cache. The
originating read request can then just unlock the pages whatever happens.

SINGLE-BLOB OBJECT SUPPORT
==========================

Single-blob objects are files for which the content of the file must be
read from or written to the server in a single operation because reading
them in parts may yield inconsistent results. AFS directories are an
example of this as there exists the possibility that the contents are
generated on the fly and would differ between reads or might change due to
third party interference.

Such objects will be written to and retrieved from the cache if one is
present, though we allow/may need to propose multiple subrequests to do so.
The important part is that read from/write to the *server* is monolithic.

Single blob reading is, for the moment, fully synchronous and does result
collection in the application thread and, also for the moment, the API is
supplied the buffer in the form of a folio_queue chain rather than using
the pagecache.

AFS CHANGES
===========

This series makes a number of changes to the kafs filesystem, primarily in
the area of directory handling:

(1) AFS's FetchData RPC reply processing is made partially asynchronous
which allows the netfs_io_request's outstanding operation counter to
be removed as part of reducing the collection to a single work item.

(2) Directory and symlink reading are plumbed through netfslib using the
single-blob object API and are now cacheable with fscache. This also
allows the afs_read struct to be eliminated and netfs_io_subrequest to
be used directly instead.

(3) Directory and symlink content are now stored in a folio_queue buffer
rather than in the pagecache. This means we don't require the RCU
read lock and xarray iteration to access it, and folios won't randomly
disappear under us because the VM wants them back.

There are some downsides to this, though: the storage folios are no
longer known to the VM, drop_caches can't flush them, the folios are
not migrateable. The inode must also be marked dirty manually to get
the data written to the cache in the background.

(4) The vnode operation lock is changed from a mutex struct to a private
lock implementation. The problem is that the lock now needs to be
dropped in a separate thread and mutexes don't permit that.

(5) When a new directory or symlink is created, we now initialise it
locally and mark it valid rather than downloading it (we know what
it's likely to look like).

(6) We now use the in-directory hashtable to reduce the number of entries
we need to scan when doing a lookup. The edit routines have to
maintain the hash chains.

(7) Cancellation (e.g. by signal) of an async call after the rxrpc_call
has been set up is now offloaded to the worker thread as there will be
a notification from rxrpc upon completion. This avoids a double
cleanup.

SUPPORTING CHANGES
==================

To support the above some other changes are also made:

(1) A "rolling buffer" implementation is created to abstract out the two
separate folio_queue chaining implementations I had (one for read and
one for write).

(2) Functions are provided to create/extend a buffer in a folio_queue
chain and tear it down again. This is used to handle AFS directories,
but could also be used to create bounce buffers for content crypto and
transport crypto.

(3) The was_async argument is dropped from netfs_read_subreq_terminated().
Instead we wake the read collection work item by either queuing it or
waking up the app thread.

(4) We don't need to use BH-excluding locks when communicating between the
issuing thread and the collection thread as neither of them now run in
BH context.

MISCELLANY
==========

Also included are a number of new tracepoints; a split of the netfslib
write collection code to put retrying into its own file (it gets more
complicated with content encryption).

There are also some minor fixes AFS included, including fixing the AFS
directory format struct layout, reducing some directory over-invalidation
and making afs_mkdir() translate EEXIST to ENOTEMPY (which is not available
on all systems the servers support).

Finally, there's a patch to try and detect entry into the folio unlock
function with no folio_queue structs in the buffer (which isn't allowed in
the cases that can get there). This is a debugging patch, but should be
minimal overhead.

* patches from https://lore.kernel.org/r/20241216204124.3752367-1-dhowells@redhat.com: (31 commits)
netfs: Report on NULL folioq in netfs_writeback_unlock_folios()
afs: Add a tracepoint for afs_read_receive()
afs: Locally initialise the contents of a new symlink on creation
afs: Use the contained hashtable to search a directory
afs: Make afs_mkdir() locally initialise a new directory's content
netfs: Change the read result collector to only use one work item
afs: Make {Y,}FS.FetchData an asynchronous operation
afs: Fix cleanup of immediately failed async calls
afs: Eliminate afs_read
afs: Use netfslib for symlinks, allowing them to be cached
afs: Use netfslib for directories
afs: Make afs_init_request() get a key if not given a file
netfs: Add support for caching single monolithic objects such as AFS dirs
netfs: Add functions to build/clean a buffer in a folio_queue
afs: Add more tracepoints to do with tracking validity
cachefiles: Add auxiliary data trace
cachefiles: Add some subrequest tracepoints
netfs: Remove some extraneous directory invalidations
afs: Fix directory format encoding struct
afs: Fix EEXIST error returned from afs_rmdir() to be ENOTEMPTY
...

Link: https://lore.kernel.org/r/20241216204124.3752367-1-dhowells@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

show more ...

afs: Use the contained hashtable to search a directory

Each directory image contains a hashtable with 128 buckets to speed up
searching. Currently, kafs does not use this, but rather iterates over

afs: Use the contained hashtable to search a directory

Each directory image contains a hashtable with 128 buckets to speed up
searching. Currently, kafs does not use this, but rather iterates over all
the occupied slots in the image as it can share this with readdir.

Switch kafs to use the hashtable for lookups to reduce the latency. Care
must be taken that the hash chains are acyclic.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-30-dhowells@redhat.com
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

show more ...

Merge branch 'next' into for-linus

Prepare input updates for 6.11 merge window.

Merge tag 'v6.9' into next

Sync up with the mainline to bring in the new cleanup API.

Merge drm/drm-next into drm-intel-gt-next

Some display refactoring patches are needed in order to allow conflict-
less merging.

Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>

Merge drm/drm-next into drm-intel-next

Sync to get the drm_printer changes to drm-intel-next.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Merge tag 'drm-misc-next-2024-02-08' into msm-next

Merge the drm-misc tree to uprev MSM CI.

Signed-off-by: Rob Clark <robdclark@chromium.org>

Merge drm/drm-next into drm-misc-next

Kickstart 6.9 development cycle.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge drm/drm-next into drm-xe-next

Sync to v6.8-rc1.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

Merge tag 'v6.8-rc4' into x86/percpu, to resolve conflicts and refresh the branch

Conflicts:
arch/x86/include/asm/percpu.h
arch/x86/include/asm/text-patching.h

Signed-off-by: Ingo Molnar <mingo@k

Merge tag 'v6.8-rc4' into x86/percpu, to resolve conflicts and refresh the branch

Conflicts:
arch/x86/include/asm/percpu.h
arch/x86/include/asm/text-patching.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>

show more ...

Merge branch 'linus' into x86/mm, to refresh the branch and pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'master' into mm-hotfixes-stable

Merge v6.8-rc1 into drm-misc-fixes

Let's kickstart the 6.8 fix cycle.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge tag 'afs-fix-rotation-20240105' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull afs updates from David Howells:
"The majority of the patches are aimed at fixing and im

Merge tag 'afs-fix-rotation-20240105' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull afs updates from David Howells:
"The majority of the patches are aimed at fixing and improving the AFS
filesystem's rotation over server IP addresses, but there are also
some fixes from Oleg Nesterov for the use of read_seqbegin_or_lock().

- Fix fileserver probe handling so that the next round of probes
doesn't break ongoing server/address rotation by clearing all the
probe result tracking. This could occasionally cause the rotation
algorithm to drop straight through, give a 'successful' result
without actually emitting any RPC calls, leaving the reply buffer
in an undefined state.

Instead, detach the probe results into a separate struct and
allocate a new one each time we start probing and update the
pointer to it. Probes are also sent in order of address preference
to try and improve the chance that the preferred one will complete
first.

- Fix server rotation so that it uses configurable address
preferences across on the probes that have completed so far than
ranking them by RTT as the latter doesn't necessarily give the best
route. The preference list can be altered by writing into
/proc/net/afs/addr_prefs.

- Fix the handling of Read-Only (and Backup) volume callbacks as
there is one per volume, not one per file, so if someone performs a
command that, say, offlines the volume but doesn't change it, when
it comes back online we don't spam the server with a status fetch
for every vnode we're using. Instead, check the Creation timestamp
in the VolSync record when prompted by a callback break.

- Handle volume regression (ie. a RW volume being restored from a
backup) by scrubbing all cache data for that volume. This is
detected from the VolSync creation timestamp.

- Adjust abort handling and abort -> error mapping to match better
with what other AFS clients do.

- Fix offline and busy volume state handling as they only apply to
individual server instances and not entire volumes and the rotation
algorithm should go and look at other servers if available. Also
make it sleep briefly before each retry if all the volume instances
are unavailable"

* tag 'afs-fix-rotation-20240105' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (40 commits)
afs: trace: Log afs_make_call(), including server address
afs: Fix offline and busy message emission
afs: Fix fileserver rotation
afs: Overhaul invalidation handling to better support RO volumes
afs: Parse the VolSync record in the reply of a number of RPC ops
afs: Don't leave DONTUSE/NEWREPSITE servers out of server list
afs: Fix comment in afs_do_lookup()
afs: Apply server breaks to mmap'd files in the call processor
afs: Move the vnode/volume validity checking code into its own file
afs: Defer volume record destruction to a workqueue
afs: Make it possible to find the volumes that are using a server
afs: Combine the endpoint state bools into a bitmask
afs: Keep a record of the current fileserver endpoint state
afs: Dispatch vlserver probes in priority order
afs: Dispatch fileserver probes in priority order
afs: Mark address lists with configured priorities
afs: Provide a way to configure address priorities
afs: Remove the unimplemented afs_cmp_addr_list()
afs: Add some more info to /proc/net/afs/servers
rxrpc: Create a procfile to display outstanding client conn bundles
...

show more ...

afs: Move the vnode/volume validity checking code into its own file

Move the code that does validity checking of vnodes and volumes with
respect to third-party changes into its own file.

Signed-off

afs: Move the vnode/volume validity checking code into its own file

Move the code that does validity checking of vnodes and volumes with
respect to third-party changes into its own file.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

show more ...

afs: Provide a way to configure address priorities

AFS servers may have multiple addresses, but the client can't easily judge
between them as to which one is best. For instance, an address that has

afs: Provide a way to configure address priorities

AFS servers may have multiple addresses, but the client can't easily judge
between them as to which one is best. For instance, an address that has a
larger RTT might actually have a better bandwidth because it goes through a
switch rather than being directly connected - but we can't work this out
dynamically unless we push through sufficient data that we can measure it.

To allow the administrator to configure this, add a list of preference
weightings for server addresses by IPv4/IPv6 address or subnet and allow
this to be viewed through a procfile and altered by writing text commands
to that same file. Preference rules can be added/updated by:

echo "add <proto> <addr>[/<subnet>] <prior>" >/proc/fs/afs/addr_prefs
echo "add udp 1.2.3.4 1000" >/proc/fs/afs/addr_prefs
echo "add udp 192.168.0.0/16 3000" >/proc/fs/afs/addr_prefs
echo "add udp 1001:2002:0:6::/64 4000" >/proc/fs/afs/addr_prefs

and removed by:

echo "del <proto> <addr>[/<subnet>]" >/proc/fs/afs/addr_prefs
echo "del udp 1.2.3.4" >/proc/fs/afs/addr_prefs

where the priority is a number between 0 and 65535.

The list is split between IPv4 and IPv6 addresses and each sublist is kept
in numerical order, with rules that would otherwise match but have
different subnet masking being ordered with the most specific submatch
first.

A subsequent patch will apply these rules.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

show more ...

Merge tag 'v5.18'

Linux 5.18

Merge branches 'fixes' and 'misc' into for-linus

Merge branch 'for-5.18/amd-sfh' into for-linus

- dead code elimination (Christophe JAILLET)

Merge tag 'v5.17-rc4' into for-linus

Merge with mainline to get the Intel ASoC generic helpers header and
other changes.

Merge tag 'v5.17-rc4' into next

Sync up with mainline to get the latest changes in HID subsystem.

Merge remote-tracking branch 'drm/drm-next' into drm-misc-next

First backmerge into drm-misc-next. Required for more helpers backmerged,
and to pull in 5.17 (rc2).

Signed-off-by: Maarten Lankhorst

Merge remote-tracking branch 'drm/drm-next' into drm-misc-next

First backmerge into drm-misc-next. Required for more helpers backmerged,
and to pull in 5.17 (rc2).

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

show more ...

Merge tag 'kvmarm-fixes-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 5.17, take #2

- A couple of fixes when handling an exception while a SEr

Merge tag 'kvmarm-fixes-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 5.17, take #2

- A couple of fixes when handling an exception while a SError has been
delivered

- Workaround for Cortex-A510's single-step[ erratum

show more ...

Merge drm/drm-next into drm-intel-gt-next

Backmerge to bring in 5.17-rc2 to introduce a common baseline
to merge i915_regs changes from drm-intel-next.

Signed-off-by: Joonas Lahtinen <joonas.lahtin

Merge drm/drm-next into drm-intel-gt-next

Backmerge to bring in 5.17-rc2 to introduce a common baseline
to merge i915_regs changes from drm-intel-next.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

show more ...