Commit Graph

1059235 Commits

Author SHA1 Message Date
David Howells
ecf5a6ce15 cachefiles: Add a couple of tracepoints for logging errors
Add two trace points to log errors, one for vfs operations like mkdir or
create, and one for I/O operations, like read, write or truncate.

Also add the beginnings of a struct that is going to represent a data file
and place a debugging ID in it for the tracepoints to record.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819625632.215744.17907340966178411033.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906926297.143852.18267924605548658911.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967135390.1823006.2512120406360156424.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021534029.640689.1875723624947577095.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:41:01 +00:00
David Howells
a70f652626 cachefiles: Add some error injection support
Add support for injecting ENOSPC or EIO errors.  This needs to be enabled
by CONFIG_CACHEFILES_ERROR_INJECTION=y.  Once enabled, ENOSPC on things
like write and mkdir can be triggered by:

        echo 1 >/proc/sys/cachefiles/error_injection

and EIO can be triggered on most operations by:

        echo 2 >/proc/sys/cachefiles/error_injection

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819624706.215744.6911916249119962943.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906925343.143852.5465695512984025812.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967134412.1823006.7354285948280296595.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021532340.640689.18209494225772443698.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:40:56 +00:00
David Howells
8390fbc465 cachefiles: Define structs
Define the cachefiles_cache struct that's going to carry the cache-level
parameters and state of a cache.

Define the beginning of the cachefiles_object struct that's going to carry
the state for a data storage object.  For the moment this is just a
debugging ID for logging purposes.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819623690.215744.2824739137193655547.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906924292.143852.15881439716653984905.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967131405.1823006.4480555941533935597.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021530610.640689.846094074334176928.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:40:45 +00:00
David Howells
77443f6171 cachefiles: Introduce rewritten driver
Introduce basic skeleton of the rewritten cachefiles driver including
config options so that it can be enabled for compilation.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819622766.215744.9108359326983195047.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906923341.143852.3856498104256721447.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967130320.1823006.15791456613198441566.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021528993.640689.9069695476048171884.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:40:39 +00:00
David Howells
16a96bdf92 fscache: Provide a function to resize a cookie
Provide a function to change the size of the storage attached to a cookie,
to match the size of the file being cached when it's changed by truncate or
fallocate:

	void fscache_resize_cookie(struct fscache_cookie *cookie,
				   loff_t new_size);

This acts synchronously and is expected to run under the inode lock of the
caller.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819621839.215744.7895597119803515402.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906922387.143852.16394459879816147793.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967128998.1823006.10740669081985775576.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021527861.640689.3466382085497236267.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:40:33 +00:00
David Howells
1f67e6d0b1 fscache: Provide a function to note the release of a page
Provide a function to be called from a network filesystem's releasepage
method to indicate that a page has been released that might have been a
reflection of data upon the server - and now that data must be reloaded
from the server or the cache.

This is used to end an optimisation for empty files, in particular files
that have just been created locally, whereby we know there cannot yet be
any data that we would need to read from the server or the cache.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819617128.215744.4725572296135656508.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906920354.143852.7511819614661372008.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967128061.1823006.611781655060034988.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021525963.640689.9264556596205140044.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:40:28 +00:00
David Howells
08276bdae6 vfs, fscache: Implement pinning of cache usage for writeback
Cachefiles has a problem in that it needs to keep the backing file for a
cookie open whilst there are local modifications pending that need to be
written to it.  However, we don't want to keep the file open indefinitely,
as that causes EMFILE/ENFILE/ENOMEM problems.

Reopening the cache file, however, is a problem if this is being done due
to writeback triggered by exit().  Some filesystems will oops if we try to
open a file in that context because they want to access current->fs or
other resources that have already been dismantled.

To get around this, I added the following:

 (1) An inode flag, I_PINNING_FSCACHE_WB, to be set on a network filesystem
     inode to indicate that we have a usage count on the cookie caching
     that inode.

 (2) A flag in struct writeback_control, unpinned_fscache_wb, that is set
     when __writeback_single_inode() clears the last dirty page from
     i_pages - at which point it clears I_PINNING_FSCACHE_WB and sets this
     flag.

     This has to be done here so that clearing I_PINNING_FSCACHE_WB can be
     done atomically with the check of PAGECACHE_TAG_DIRTY that clears
     I_DIRTY_PAGES.

 (3) A function, fscache_set_page_dirty(), which if it is not set, sets
     I_PINNING_FSCACHE_WB and calls fscache_use_cookie() to pin the cache
     resources.

 (4) A function, fscache_unpin_writeback(), to be called by ->write_inode()
     to unuse the cookie.

 (5) A function, fscache_clear_inode_writeback(), to be called when the
     inode is evicted, before clear_inode() is called.  This cleans up any
     lingering I_PINNING_FSCACHE_WB.

The network filesystem can then use these tools to make sure that
fscache_write_to_cache() can write locally modified data to the cache as
well as to the server.

For the future, I'm working on write helpers for netfs lib that should
allow this facility to be removed by keeping track of the dirty regions
separately - but that's incomplete at the moment and is also going to be
affected by folios, one way or another, since it deals with pages

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819615157.215744.17623791756928043114.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906917856.143852.8224898306177154573.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967124567.1823006.14188359004568060298.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021524705.640689.17824932021727663017.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
b6e16652d6 fscache: Implement higher-level write I/O interface
Provide a higher-level function than fscache_write() to perform a write
from an inode's pagecache to the cache, whilst fending off concurrent
writes by means of the PG_fscache mark on a page:

	void fscache_write_to_cache(struct fscache_cookie *cookie,
				    struct address_space *mapping,
				    loff_t start,
				    size_t len,
				    loff_t i_size,
				    netfs_io_terminated_t term_func,
				    void *term_func_priv,
				    bool caching);

If caching is false, this function does nothing except call (*term_func)()
if given.  It assumes that, in such a case, PG_fscache will not have been
set on the pages.

Otherwise, if caching is true, this function requires the source pages to
have had PG_fscache set on them before calling.  start and len define the
region of the file to be modified and i_size indicates the new file size.
The source pages are extracted from the mapping.

term_func and term_func_priv work as for fscache_write().  The PG_fscache
marks will be cleared at the end of the operation, before term_func is
called or the function otherwise returns.

There is an additonal helper function to clear the PG_fscache bits from a
range of pages:

	void fscache_clear_page_bits(struct fscache_cookie *cookie,
				     struct address_space *mapping,
				     loff_t start, size_t len,
				     bool caching);

If caching is true, the pages to be managed are expected to be located on
mapping in the range defined by start and len.  If caching is false, it
does nothing.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819614155.215744.5528123235123721230.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906916346.143852.15632773570362489926.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967123599.1823006.12946816026724657428.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021522672.640689.4381958316198807813.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
9af1c6c308 fscache: Implement raw I/O interface
Provide a pair of functions to perform raw I/O on the cache.  The first
function allows an arbitrary asynchronous direct-IO read to be made against
a cache object, though the read should be aligned and sized appropriately
for the backing device:

        int fscache_read(struct netfs_cache_resources *cres,
                         loff_t start_pos,
                         struct iov_iter *iter,
                         enum netfs_read_from_hole read_hole,
                         netfs_io_terminated_t term_func,
                         void *term_func_priv);

The cache resources must have been previously initialised by
fscache_begin_read_operation().  A read operation is sent to the backing
filesystem, starting at start_pos within the file.  The size of the read is
specified by the iterator, as is the location of the output buffer.

If there is a hole in the data it can be ignored and left to the backing
filesystem to deal with (NETFS_READ_HOLE_IGNORE), a hole at the beginning
can be skipped over and the buffer padded with zeros
(NETFS_READ_HOLE_CLEAR) or -ENODATA can be given (NETFS_READ_HOLE_FAIL).

If term_func is not NULL, the operation may be performed asynchronously.
Upon completion, successful or otherwise, (*term_func)() will be called and
passed term_func_priv, along with an error or the amount of data
transferred.  If the op is run asynchronously, fscache_read() will return
-EIOCBQUEUED.

The second function allows an arbitrary asynchronous direct-IO write to be
made against a cache object, though the write should be aligned and sized
appropriately for the backing device:

        int fscache_write(struct netfs_cache_resources *cres,
                          loff_t start_pos,
                          struct iov_iter *iter,
                          netfs_io_terminated_t term_func,
                          void *term_func_priv);

This works in very similar way to fscache_read(), except that there's no
need to deal with holes (they're just overwritten).

The caller is responsible for preventing concurrent overlapping writes.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819613224.215744.7877577215582621254.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906915386.143852.16936177636106480724.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967122632.1823006.7487049517698562172.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021521420.640689.12747258780542678309.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
3a11b3a863 netfs: Pass more information on how to deal with a hole in the cache
Pass more information to the cache on how to deal with a hole if it
encounters one when trying to read from the cache.  Three options are
provided:

 (1) NETFS_READ_HOLE_IGNORE.  Read the hole along with the data, assuming
     it to be a punched-out extent by the backing filesystem.

 (2) NETFS_READ_HOLE_CLEAR.  If there's a hole, erase the requested region
     of the cache and clear the read buffer.

 (3) NETFS_READ_HOLE_FAIL.  Fail the read if a hole is detected.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819612321.215744.9738308885948264476.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906914460.143852.6284247083607910189.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967119923.1823006.15637375885194297582.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021519762.640689.16994364383313159319.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
ed1235eb78 fscache: Provide a function to let the netfs update its coherency data
Provide a function to let the netfs update its coherency data:

	void fscache_update_cookie(struct fscache_cookie *cookie,
				   const void *aux_data,
				   const loff_t *object_size);

This will update the auxiliary data and/or the size of the object attached
to a cookie if either pointer is not-NULL and flag that the disk needs to
be updated.

Note that fscache_unuse_cookie() also allows this to be done.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819610438.215744.4223265964131424954.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906913530.143852.18150303220217653820.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967117795.1823006.7493373142653442595.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021518440.640689.6369952464473039268.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
8e7a867bb7 fscache: Provide read/write stat counters for the cache
Provide read/write stat counters for the cache backend to use.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819609532.215744.10821082637727410554.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906912598.143852.12960327989649429069.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967113830.1823006.3222957649202368162.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021517502.640689.6077928311710357342.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
cdf262f294 fscache: Count data storage objects in a cache
Count the data storage objects that are currently allocated in a cache.
This is used to pin certain cache structures until cache withdrawal is
complete.

Three helpers are provided to manage and make use of the count:

 (1) void fscache_count_object(struct fscache_cache *cache);

     This should be called by the cache backend to note that an object has
     been allocated and attached to the cache.

 (2) void fscache_uncount_object(struct fscache_cache *cache);

     This should be called by the backend to note that an object has been
     destroyed.  This sends a wakeup event that allows cache withdrawal to
     proceed if it was waiting for that object.

 (3) void fscache_wait_for_objects(struct fscache_cache *cache);

     This can be used by the backend to wait for all outstanding cache
     object to be destroyed.

Each cache's counter is displayed as part of /proc/fs/fscache/caches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819608594.215744.1812706538117388252.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906911646.143852.168184059935530127.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967111846.1823006.9868154941573671255.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021516219.640689.4934796654308958158.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
d64f4554dd fscache: Provide a means to begin an operation
Provide a function to begin a read operation:

	int fscache_begin_read_operation(
		struct netfs_cache_resources *cres,
		struct fscache_cookie *cookie)

This is primarily intended to be called by network filesystems on behalf of
netfslib, but may also be called to use the I/O access functions directly.
It attaches the resources required by the cache to cres struct from the
supplied cookie.

This holds access to the cache behind the cookie for the duration of the
operation and forces cache withdrawal and cookie invalidation to perform
synchronisation on the operation.  cres->inval_counter is set from the
cookie at this point so that it can be compared at the end of the
operation.

Note that this does not guarantee that the cache state is fully set up and
able to perform I/O immediately; looking up and creation may be left in
progress in the background.  The operations intended to be called by the
network filesystem, such as reading and writing, are expected to wait for
the cookie to move to the correct state.

This will, however, potentially sleep, waiting for a certain minimum state
to be set or for operations such as invalidate to advance far enough that
I/O can resume.


Also provide a function for the cache to call to wait for the cache object
to get to a state where it can be used for certain things:

	bool fscache_wait_for_operation(struct netfs_cache_resources *cres,
					enum fscache_want_stage stage);

This looks at the cache resources provided by the begin function and waits
for them to get to an appropriate stage.  There's a choice of wanting just
some parameters (FSCACHE_WANT_PARAM) or the ability to do I/O
(FSCACHE_WANT_READ or FSCACHE_WANT_WRITE).

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819603692.215744.146724961588817028.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906910672.143852.13856103384424986357.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967110245.1823006.2239170567540431836.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021513617.640689.16627329360866150606.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
d24af13e2e fscache: Implement cookie invalidation
Add a function to invalidate the cache behind a cookie:

	void fscache_invalidate(struct fscache_cookie *cookie,
				const void *aux_data,
				loff_t size,
				unsigned int flags)

This causes any cached data for the specified cookie to be discarded.  If
the cookie is marked as being in use, a new cache object will be created if
possible and future I/O will use that instead.  In-flight I/O should be
abandoned (writes) or reconsidered (reads).  Each time it is called
cookie->inval_counter is incremented and this can be used to detect
invalidation at the end of an I/O operation.

The coherency data attached to the cookie can be updated and the cookie
size should be reset.  One flag is available, FSCACHE_INVAL_DIO_WRITE,
which should be used to indicate invalidation due to a DIO write on a
file.  This will temporarily disable caching for this cookie.

Changes
=======
ver #2:
 - Should only change to inval state if can get access to cache.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819602231.215744.11206598147269491575.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906909707.143852.18056070560477964891.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967107447.1823006.5945029409592119962.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021512640.640689.11418616313147754172.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
12bb21a29c fscache: Implement cookie user counting and resource pinning
Provide a pair of functions to count the number of users of a cookie (open
files, writeback, invalidation, resizing, reads, writes), to obtain and pin
resources for the cookie and to prevent culling for the whilst there are
users.

The first function marks a cookie as being in use:

	void fscache_use_cookie(struct fscache_cookie *cookie,
				bool will_modify);

The caller should indicate the cookie to use and whether or not the caller
is in a context that may modify the cookie (e.g. a file open O_RDWR).

If the cookie is not already resourced, fscache will ask the cache backend
in the background to do whatever it needs to look up, create or otherwise
obtain the resources necessary to access data.  This is pinned to the
cookie and may not be culled, though it may be withdrawn if the cache as a
whole is withdrawn.

The second function removes the in-use mark from a cookie and, optionally,
updates the coherency data:

	void fscache_unuse_cookie(struct fscache_cookie *cookie,
				  const void *aux_data,
				  const loff_t *object_size);

If non-NULL, the aux_data buffer and/or the object_size will be saved into
the cookie and will be set on the backing store when the object is
committed.

If this removes the last usage on a cookie, the cookie is placed onto an
LRU list from which it will be removed and closed after a couple of seconds
if it doesn't get reused.  This prevents resource overload in the cache -
in particular it prevents it from holding too many files open.

Changes
=======
ver #2:
 - Fix fscache_unuse_cookie() to use atomic_dec_and_lock() to avoid a
   potential race if the cookie gets reused before it completes the
   unusement.
 - Added missing transition to LRU_DISCARDING state.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819600612.215744.13678350304176542741.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906907567.143852.16979631199380722019.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967106467.1823006.6790864931048582667.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021511674.640689.10084988363699111860.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
5d00e426f9 fscache: Implement simple cookie state machine
Implement a very simple cookie state machine to handle lookup,
invalidation, withdrawal, relinquishment and, to be added later, commit on
LRU discard.

Three cache methods are provided: ->lookup_cookie() to look up and, if
necessary, create a data storage object; ->withdraw_cookie() to free the
resources associated with that object and potentially delete it; and
->prepare_to_write(), to do prepare for changes to the cached data to be
modified locally.

Changes
=======
ver #3:
 - Fix a race between LRU discard and relinquishment whereby the former
   would override the latter and thus the latter would never happen[1].

ver #2:
 - Don't hold n_accesses elevated whilst cache is bound to a cookie, but
   rather add a flag that prevents the state machine from being queued when
   n_accesses reaches 0.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/599331.1639410068@warthog.procyon.org.uk/ [1]
Link: https://lore.kernel.org/r/163819599657.215744.15799615296912341745.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906903925.143852.1805855338154353867.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967105456.1823006.14730395299835841776.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021510706.640689.7961423370243272583.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
29f18e79fe fscache: Add a function for a cache backend to note an I/O error
Add a function to the backend API to note an I/O error in a cache.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819598741.215744.891281275151382095.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906901316.143852.15225412215771586528.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967100721.1823006.16435671567428949398.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021508840.640689.11902836226570620424.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
bfa22da3ed fscache: Provide and use cache methods to lookup/create/free a volume
Add cache methods to lookup, create and remove a volume.

Looking up or creating the volume requires the cache pinning for access;
freeing the volume requires the volume pinning for access.  The
->acquire_volume() method is used to ask the cache backend to lookup and,
if necessary, create a volume; the ->free_volume() method is used to free
the resources for a volume.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819597821.215744.5225318658134989949.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906898645.143852.8537799955945956818.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967099771.1823006.1455197910571061835.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021507345.640689.4073511598838843040.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
2e0c76aee2 fscache: Implement functions add/remove a cache
Implement functions to allow the cache backend to add or remove a cache:

 (1) Declare a cache to be live:

	int fscache_add_cache(struct fscache_cache *cache,
			      const struct fscache_cache_ops *ops,
			      void *cache_priv);

     Take a previously acquired cache cookie, set the operations table and
     private data and mark the cache open for access.

 (2) Withdraw a cache from service:

	void fscache_withdraw_cache(struct fscache_cache *cache);

     This marks the cache as withdrawn and thus prevents further
     cache-level and volume-level accesses.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819596022.215744.8799712491432238827.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906896599.143852.17049208999019262884.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967097870.1823006.3470041000971522030.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021505541.640689.1819714759326331054.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
a7733fb632 fscache: Implement cookie-level access helpers
Add a number of helper functions to manage access to a cookie, pinning the
cache object in place for the duration to prevent cache withdrawal from
removing it:

 (1) void fscache_init_access_gate(struct fscache_cookie *cookie);

     This function initialises the access count when a cache binds to a
     cookie.  An extra ref is taken on the access count to prevent wakeups
     while the cache is active.  We're only interested in the wakeup when a
     cookie is being withdrawn and we're waiting for it to quiesce - at
     which point the counter will be decremented before the wait.

     The FSCACHE_COOKIE_NACC_ELEVATED flag is set on the cookie to keep
     track of the extra ref in order to handle a race between
     relinquishment and withdrawal both trying to drop the extra ref.

 (2) bool fscache_begin_cookie_access(struct fscache_cookie *cookie,
				      enum fscache_access_trace why);

     This function attempts to begin access upon a cookie, pinning it in
     place if it's cached.  If successful, it returns true and leaves a the
     access count incremented.

 (3) void fscache_end_cookie_access(struct fscache_cookie *cookie,
				    enum fscache_access_trace why);

     This function drops the access count obtained by (2), permitting
     object withdrawal to take place when it reaches zero.

A tracepoint is provided to track changes to the access counter on a
cookie.

Changes
=======
ver #2:
 - Don't hold n_accesses elevated whilst cache is bound to a cookie, but
   rather add a flag that prevents the state machine from being queued when
   n_accesses reaches 0.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819595085.215744.1706073049250505427.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906895313.143852.10141619544149102193.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967095980.1823006.1133648159424418877.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021503063.640689.8870918985269528670.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
e6acd3299b fscache: Implement volume-level access helpers
Add a pair of helper functions to manage access to a volume, pinning the
volume in place for the duration to prevent cache withdrawal from removing
it:

	bool fscache_begin_volume_access(struct fscache_volume *volume,
					 enum fscache_access_trace why);
	void fscache_end_volume_access(struct fscache_volume *volume,
				       enum fscache_access_trace why);

The way the access gate on the volume works/will work is:

  (1) If the cache tests as not live (state is not FSCACHE_CACHE_IS_ACTIVE),
      then we return false to indicate access was not permitted.

  (2) If the cache tests as live, then we increment the volume's n_accesses
      count and then recheck the cache liveness, ending the access if it
      ceased to be live.

  (3) When we end the access, we decrement the volume's n_accesses and wake
      up the any waiters if it reaches 0.

  (4) Whilst the cache is caching, the volume's n_accesses is kept
      artificially incremented to prevent wakeups from happening.

  (5) When the cache is taken offline, the state is changed to prevent new
      accesses, the volume's n_accesses is decremented and we wait for it to
      become 0.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819594158.215744.8285859817391683254.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906894315.143852.5454793807544710479.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967095028.1823006.9173132503876627466.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021501546.640689.9631510472149608443.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
23e12e285a fscache: Implement cache-level access helpers
Add a pair of functions to pin/unpin a cache that we're wanting to do a
high-level access to (such as creating or removing a volume):

	bool fscache_begin_cache_access(struct fscache_cache *cache,
					enum fscache_access_trace why);
	void fscache_end_cache_access(struct fscache_cache *cache,
				      enum fscache_access_trace why);

The way the access gate works/will work is:

 (1) If the cache tests as not live (state is not FSCACHE_CACHE_IS_ACTIVE),
     then we return false to indicate access was not permitted.

 (2) If the cache tests as live, then we increment the n_accesses count and
     then recheck the liveness, ending the access if it ceased to be live.

 (3) When we end the access, we decrement n_accesses and wake up the any
     waiters if it reaches 0.

 (4) Whilst the cache is caching, n_accesses is kept artificially
     incremented to prevent wakeups from happening.

 (5) When the cache is taken offline, the state is changed to prevent new
     accesses, n_accesses is decremented and we wait for n_accesses to
     become 0.

Note that some of this is implemented in a later patch.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819593239.215744.7537428720603638088.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906893368.143852.14164004598465617981.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967093977.1823006.6967886507023056409.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021499995.640689.18286203753480287850.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
7f3283aba3 fscache: Implement cookie registration
Add functions to the fscache API to allow data file cookies to be acquired
and relinquished by the network filesystem.  It is intended that the
filesystem will create such cookies per-inode under a volume.

To request a cookie, the filesystem should call:

	struct fscache_cookie *
	fscache_acquire_cookie(struct fscache_volume *volume,
			       u8 advice,
			       const void *index_key,
			       size_t index_key_len,
			       const void *aux_data,
			       size_t aux_data_len,
			       loff_t object_size)


The filesystem must first have created a volume cookie, which is passed in
here.  If it passes in NULL then the function will just return a NULL
cookie.

A binary key should be passed in index_key and is of size index_key_len.
This is saved in the cookie and is used to locate the associated data in
the cache.

A coherency data buffer of size aux_data_len will be allocated and
initialised from the buffer pointed to by aux_data.  This is used to
validate cache objects when they're opened and is stored on disk with them
when they're committed.  The data is stored in the cookie and will be
updateable by various functions in later patches.

The object_size must also be given.  This is also used to perform a
coherency check and to size the backing storage appropriately.

This function disallows a cookie from being acquired twice in parallel,
though it will cause the second user to wait if the first is busy
relinquishing its cookie.


When a network filesystem has finished with a cookie, it should call:

	void
	fscache_relinquish_cookie(struct fscache_volume *volume,
				  bool retire)

If retire is true, any backing data will be discarded immediately.

Changes
=======
ver #3:
 - fscache_hash()'s size parameter is now in bytes.  Use __le32 as the unit
   to round up to.
 - When comparing cookies, simply see if the attributes are the same rather
   than subtracting them to produce a strcmp-style return[1].
 - Add a check to see if the cookie is still hashed at the point of
   freeing.

ver #2:
 - Don't hold n_accesses elevated whilst cache is bound to a cookie, but
   rather add a flag that prevents the state machine from being queued when
   n_accesses reaches 0.
 - Remove the unused cookie pointer field from the fscache_acquire
   tracepoint.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/CAHk-=whtkzB446+hX0zdLsdcUJsJ=8_-0S1mE_R+YurThfUbLA@mail.gmail.com/ [1]
Link: https://lore.kernel.org/r/163819590658.215744.14934902514281054323.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906891983.143852.6219772337558577395.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967088507.1823006.12659006350221417165.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021498432.640689.12743483856927722772.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
62ab633523 fscache: Implement volume registration
Add functions to the fscache API to allow volumes to be acquired and
relinquished by the network filesystem.  A volume is an index of data
storage cache objects.  A volume is represented by a volume cookie in the
API.  A filesystem would typically create a volume for a superblock and
then create per-inode cookies within it.

To request a volume, the filesystem calls:

	struct fscache_volume *
	fscache_acquire_volume(const char *volume_key,
			       const char *cache_name,
			       const void *coherency_data,
			       size_t coherency_len)

The volume_key is a printable string used to match the volume in the cache.
It should not contain any '/' characters.  For AFS, for example, this would
be "afs,<cellname>,<volume_id>", e.g. "afs,example.com,523001".

The cache_name can be NULL, but if not it should be a string indicating the
name of the cache to use if there's more than one available.

The coherency data, if given, is an arbitrarily-sized blob that's attached
to the volume and is compared when the volume is looked up.  If it doesn't
match, the old volume is judged to be out of date and it and everything
within it is discarded.

Acquiring a volume twice concurrently is disallowed, though the function
will wait if an old volume cookie is being relinquishing.


When a network filesystem has finished with a volume, it should return the
volume cookie by calling:

	void
	fscache_relinquish_volume(struct fscache_volume *volume,
				  const void *coherency_data,
				  bool invalidate)

If invalidate is true, the entire volume will be discarded; if false, the
volume will be synced and the coherency data will be updated.

Changes
=======
ver #4:
 - Removed an extraneous param from kdoc on fscache_relinquish_volume()[3].

ver #3:
 - fscache_hash()'s size parameter is now in bytes.  Use __le32 as the unit
   to round up to.
 - When comparing cookies, simply see if the attributes are the same rather
   than subtracting them to produce a strcmp-style return[2].
 - Make the coherency data an arbitrary blob rather than a u64, but don't
   store it for the moment.

ver #2:
 - Fix error check[1].
 - Make a fscache_acquire_volume() return errors, including EBUSY if a
   conflicting volume cookie already exists.  No error is printed now -
   that's left to the netfs.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/20211203095608.GC2480@kili/ [1]
Link: https://lore.kernel.org/r/CAHk-=whtkzB446+hX0zdLsdcUJsJ=8_-0S1mE_R+YurThfUbLA@mail.gmail.com/ [2]
Link: https://lore.kernel.org/r/20211220224646.30e8205c@canb.auug.org.au/ [3]
Link: https://lore.kernel.org/r/163819588944.215744.1629085755564865996.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906890630.143852.13972180614535611154.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967086836.1823006.8191672796841981763.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021495816.640689.4403156093668590217.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
9549332df4 fscache: Implement cache registration
Implement a register of caches and provide functions to manage it.

Two functions are provided for the cache backend to use:

 (1) Acquire a cache cookie:

	struct fscache_cache *fscache_acquire_cache(const char *name)

     This gets the cache cookie for a cache of the specified name and moves
     it to the preparation state.  If a nameless cache cookie exists, that
     will be given this name and used.

 (2) Relinquish a cache cookie:

	void fscache_relinquish_cache(struct fscache_cache *cache);

     This relinquishes a cache cookie, cleans it and makes it available if
     it's still referenced by a network filesystem.

Note that network filesystems don't deal with cache cookies directly, but
rather go straight to the volume registration.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819587157.215744.13523139317322503286.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906889665.143852.10378009165231294456.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967085081.1823006.2218944206363626210.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021494847.640689.10109692261640524343.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
e8a07c9d22 fscache: Implement a hash function
Implement a function to generate hashes.  It needs to be stable over time
and endianness-independent as the hashes will appear on disk in future
patches.  It can assume that its input is a multiple of four bytes in size
and alignment.

This is borrowed from the VFS and simplified.  le32_to_cpu() is added to
make it endianness-independent.

Changes
=======
ver #3:
 - Read the data being hashed in an endianness-independent way[1].
 - Change the size parameter to be in bytes rather than words.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/CAHk-=whtkzB446+hX0zdLsdcUJsJ=8_-0S1mE_R+YurThfUbLA@mail.gmail.com [1]
Link: https://lore.kernel.org/r/163819586113.215744.1699465806130102367.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906888735.143852.10944614318596881429.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967082342.1823006.8915671045444488742.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021493624.640689.9990442668811178628.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
1e1236b841 fscache: Introduce new driver
Introduce basic skeleton of the new, rewritten fscache driver.

Changes
=======
ver #3:
 - Use remove_proc_subtree(), not remove_proc_entry() to remove a populated
   dir.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819584034.215744.4290533472390439030.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906887770.143852.3577888294989185666.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967080039.1823006.5702921801104057922.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021491014.640689.4292699878317589512.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
a39c41b853 netfs: Pass a flag to ->prepare_write() to say if there's no alloc'd space
Pass a flag to ->prepare_write() to indicate if there's definitely no
space allocated in the cache yet (for instance if we've already checked as
we were asked to do a read).

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819583123.215744.12783808230464471417.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906886835.143852.6689886781122679769.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967079100.1823006.12889542712309574359.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021489334.640689.3131206613015409076.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
9e1aa6b8f4 netfs: Display the netfs inode number in the netfs_read tracepoint
Display the netfs inode number in the netfs_read tracepoint so that this
can be used to correlate with the cachefiles_prep_read tracepoint.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819581097.215744.17476611915583897051.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906885903.143852.12229407815154182247.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967078164.1823006.15286989199782861123.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021487412.640689.7544388469390936443.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
2cee6fbb7f fscache: Remove the contents of the fscache driver, pending rewrite
Remove the code that comprises the fscache driver as it's going to be
substantially rewritten, with the majority of the code being erased in the
rewrite.

A small piece of linux/fscache.h is left as that is #included by a bunch of
network filesystems.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819578724.215744.18210619052245724238.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906884814.143852.6727245089843862889.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967077097.1823006.1377665951499979089.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021485548.640689.13876080567388696162.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
850cba069c cachefiles: Delete the cachefiles driver pending rewrite
Delete the code from the cachefiles driver to make it easier to rewrite and
resubmit in a logical manner.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819577641.215744.12718114397770666596.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906883770.143852.4149714614981373410.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967076066.1823006.7175712134577687753.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021483619.640689.7586546280515844702.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
01491a7565 fscache, cachefiles: Disable configuration
Disable fscache and cachefiles in Kconfig whilst it is rewritten.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819576672.215744.12444272479560406780.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906882835.143852.11073015983885872901.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967075113.1823006.277316290062782998.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021481179.640689.2004199594774033658.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:21:44 +00:00
Jeffle Xu
3cfef1b612 netfs: fix parameter of cleanup()
The order of these two parameters is just reversed. gcc didn't warn on
that, probably because 'void *' can be converted from or to other
pointer types without warning.

Cc: stable@vger.kernel.org
Fixes: 3d3c950467 ("netfs: Provide readahead and readpage netfs helpers")
Fixes: e1b1240c1f ("netfs: Add write_begin helper")
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Link: https://lore.kernel.org/r/20211207031449.100510-1-jefflexu@linux.alibaba.com/ # v1
2021-12-07 15:47:09 +00:00
David Howells
598ad0bd09 netfs: Fix lockdep warning from taking sb_writers whilst holding mmap_lock
Taking sb_writers whilst holding mmap_lock isn't allowed and will result in
a lockdep warning like that below.  The problem comes from cachefiles
needing to take the sb_writers lock in order to do a write to the cache,
but being asked to do this by netfslib called from readpage, readahead or
write_begin[1].

Fix this by always offloading the write to the cache off to a worker
thread.  The main thread doesn't need to wait for it, so deadlock can be
avoided.

This can be tested by running the quick xfstests on something like afs or
ceph with lockdep enabled.

WARNING: possible circular locking dependency detected
5.15.0-rc1-build2+ #292 Not tainted
------------------------------------------------------
holetest/65517 is trying to acquire lock:
ffff88810c81d730 (mapping.invalidate_lock#3){.+.+}-{3:3}, at: filemap_fault+0x276/0x7a5

but task is already holding lock:
ffff8881595b53e8 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x28d/0x59c

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&mm->mmap_lock#2){++++}-{3:3}:
       validate_chain+0x3c4/0x4a8
       __lock_acquire+0x89d/0x949
       lock_acquire+0x2dc/0x34b
       __might_fault+0x87/0xb1
       strncpy_from_user+0x25/0x18c
       removexattr+0x7c/0xe5
       __do_sys_fremovexattr+0x73/0x96
       do_syscall_64+0x67/0x7a
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #1 (sb_writers#10){.+.+}-{0:0}:
       validate_chain+0x3c4/0x4a8
       __lock_acquire+0x89d/0x949
       lock_acquire+0x2dc/0x34b
       cachefiles_write+0x2b3/0x4bb
       netfs_rreq_do_write_to_cache+0x3b5/0x432
       netfs_readpage+0x2de/0x39d
       filemap_read_page+0x51/0x94
       filemap_get_pages+0x26f/0x413
       filemap_read+0x182/0x427
       new_sync_read+0xf0/0x161
       vfs_read+0x118/0x16e
       ksys_read+0xb8/0x12e
       do_syscall_64+0x67/0x7a
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #0 (mapping.invalidate_lock#3){.+.+}-{3:3}:
       check_noncircular+0xe4/0x129
       check_prev_add+0x16b/0x3a4
       validate_chain+0x3c4/0x4a8
       __lock_acquire+0x89d/0x949
       lock_acquire+0x2dc/0x34b
       down_read+0x40/0x4a
       filemap_fault+0x276/0x7a5
       __do_fault+0x96/0xbf
       do_fault+0x262/0x35a
       __handle_mm_fault+0x171/0x1b5
       handle_mm_fault+0x12a/0x233
       do_user_addr_fault+0x3d2/0x59c
       exc_page_fault+0x85/0xa5
       asm_exc_page_fault+0x1e/0x30

other info that might help us debug this:

Chain exists of:
  mapping.invalidate_lock#3 --> sb_writers#10 --> &mm->mmap_lock#2

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&mm->mmap_lock#2);
                               lock(sb_writers#10);
                               lock(&mm->mmap_lock#2);
  lock(mapping.invalidate_lock#3);

 *** DEADLOCK ***

1 lock held by holetest/65517:
 #0: ffff8881595b53e8 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x28d/0x59c

stack backtrace:
CPU: 0 PID: 65517 Comm: holetest Not tainted 5.15.0-rc1-build2+ #292
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
Call Trace:
 dump_stack_lvl+0x45/0x59
 check_noncircular+0xe4/0x129
 ? print_circular_bug+0x207/0x207
 ? validate_chain+0x461/0x4a8
 ? add_chain_block+0x88/0xd9
 ? hlist_add_head_rcu+0x49/0x53
 check_prev_add+0x16b/0x3a4
 validate_chain+0x3c4/0x4a8
 ? check_prev_add+0x3a4/0x3a4
 ? mark_lock+0xa5/0x1c6
 __lock_acquire+0x89d/0x949
 lock_acquire+0x2dc/0x34b
 ? filemap_fault+0x276/0x7a5
 ? rcu_read_unlock+0x59/0x59
 ? add_to_page_cache_lru+0x13c/0x13c
 ? lock_is_held_type+0x7b/0xd3
 down_read+0x40/0x4a
 ? filemap_fault+0x276/0x7a5
 filemap_fault+0x276/0x7a5
 ? pagecache_get_page+0x2dd/0x2dd
 ? __lock_acquire+0x8bc/0x949
 ? pte_offset_kernel.isra.0+0x6d/0xc3
 __do_fault+0x96/0xbf
 ? do_fault+0x124/0x35a
 do_fault+0x262/0x35a
 ? handle_pte_fault+0x1c1/0x20d
 __handle_mm_fault+0x171/0x1b5
 ? handle_pte_fault+0x20d/0x20d
 ? __lock_release+0x151/0x254
 ? mark_held_locks+0x1f/0x78
 ? rcu_read_unlock+0x3a/0x59
 handle_mm_fault+0x12a/0x233
 do_user_addr_fault+0x3d2/0x59c
 ? pgtable_bad+0x70/0x70
 ? rcu_read_lock_bh_held+0xab/0xab
 exc_page_fault+0x85/0xa5
 ? asm_exc_page_fault+0x8/0x30
 asm_exc_page_fault+0x1e/0x30
RIP: 0033:0x40192f
Code: ff 48 89 c3 48 8b 05 50 28 00 00 48 85 ed 7e 23 31 d2 4b 8d 0c 2f eb 0a 0f 1f 00 48 8b 05 39 28 00 00 48 0f af c2 48 83 c2 01 <48> 89 1c 01 48 39 d5 7f e8 8b 0d f2 27 00 00 31 c0 85 c9 74 0e 8b
RSP: 002b:00007f9931867eb0 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 00007f9931868700 RCX: 00007f993206ac00
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 00007ffc13e06ee0
RBP: 0000000000000100 R08: 0000000000000000 R09: 00007f9931868700
R10: 00007f99318689d0 R11: 0000000000000202 R12: 00007ffc13e06ee0
R13: 0000000000000c00 R14: 00007ffc13e06e00 R15: 00007f993206a000

Fixes: 726218fdc2 ("netfs: Define an interface to talk to a cache")
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jeff Layton <jlayton@kernel.org>
cc: Jan Kara <jack@suse.cz>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20210922110420.GA21576@quack2.suse.cz/ [1]
Link: https://lore.kernel.org/r/163887597541.1596626.2668163316598972956.stgit@warthog.procyon.org.uk/ # v1
2021-12-07 13:39:55 +00:00
Linus Torvalds
0fcfb00b28 Linux 5.16-rc4 2021-12-05 14:08:22 -08:00
Linus Torvalds
268ba09537 parisc architecture bug and warning fixes for kernel v5.16-rc4
Some bug and warning fixes:
 - Fix "make install" to use debians "installkernel" script which is now in /usr/sbin
 - Fix the bindeb-pkg make target by giving the correct KBUILD_IMAGE file name
 - Fix compiler warnings by annotating parisc agp init functions with __init
 - Fix timekeeping on SMP machines with dual-core CPUs
 - Enable some more config options in the 64-bit defconfig
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Merge tag 'for-5.16/parisc-6' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc fixes from Helge Deller:
 "Some bug and warning fixes:

   - Fix "make install" to use debians "installkernel" script which is
     now in /usr/sbin

   - Fix the bindeb-pkg make target by giving the correct KBUILD_IMAGE
     file name

   - Fix compiler warnings by annotating parisc agp init functions with
     __init

   - Fix timekeeping on SMP machines with dual-core CPUs

   - Enable some more config options in the 64-bit defconfig"

* tag 'for-5.16/parisc-6' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Mark cr16 CPU clocksource unstable on all SMP machines
  parisc: Fix "make install" on newer debian releases
  parisc/agp: Annotate parisc agp init functions with __init
  parisc: Enable sata sil, audit and usb support on 64-bit defconfig
  parisc: Fix KBUILD_IMAGE for self-extracting kernel
2021-12-05 12:58:18 -08:00
Linus Torvalds
944207047c USB fixes for 5.16-rc4
Here are some small USB fixes for a few reported issues.  Included in
 here are:
 	- xhci fix for a _much_ reported regression.  I don't think
 	  there's a community distro that has not reported this problem
 	  yet :(
 	- new USB quirk addition
 	- cdns3 minor fixes
 	- typec regression fix.
 
 All of these have been in linux-next with no reported problems, and the
 xhci fix has been reported by many to resolve their reported problem.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'usb-5.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB fixes from Greg KH:
 "Here are some small USB fixes for a few reported issues. Included in
  here are:

   - xhci fix for a _much_ reported regression. I don't think there's a
     community distro that has not reported this problem yet :(

   - new USB quirk addition

   - cdns3 minor fixes

   - typec regression fix.

  All of these have been in linux-next with no reported problems, and
  the xhci fix has been reported by many to resolve their reported
  problem"

* tag 'usb-5.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()
  usb: cdns3: gadget: fix new urb never complete if ep cancel previous requests
  usb: typec: tcpm: Wait in SNK_DEBOUNCED until disconnect
  USB: NO_LPM quirk Lenovo Powered USB-C Travel Hub
  xhci: Fix commad ring abort, write all 64 bits to CRCR register.
2021-12-05 09:34:57 -08:00
Linus Torvalds
5163953950 TTY/Serial fixes for 5.16-rc4
Here are some small TTY and Serial driver fixes for 5.16-rc4 to resolve
 a number of reported problems.
 
 They include:
 	- liteuart serial driver fixes
 	- 8250_pci serial driver fixes for pericom devices
 	- 8250 RTS line control fix while in RS-485 mode
 	- tegra serial driver fix
 	- msm_serial driver fix
 	- pl011 serial driver new id
 	- fsl_lpuart revert of broken change
 	- 8250_bcm7271 serial driver fix
 	- MAINTAINERS file update for rpmsg tty driver that came in
 	  5.16-rc1
 	- vgacon fix for reported problem
 
 All of these, except for the 8250_bcm7271 fix have been in linux-next
 with no reported problem.  The 8250_bcm7271 fix was added to the tree on
 Friday so no chance to be linux-next yet.  But it should be fine as the
 affected developers submitted it.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-5.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial fixes from Greg KH:
 "Here are some small TTY and Serial driver fixes for 5.16-rc4 to
  resolve a number of reported problems.

  They include:

   - liteuart serial driver fixes

   - 8250_pci serial driver fixes for pericom devices

   - 8250 RTS line control fix while in RS-485 mode

   - tegra serial driver fix

   - msm_serial driver fix

   - pl011 serial driver new id

   - fsl_lpuart revert of broken change

   - 8250_bcm7271 serial driver fix

   - MAINTAINERS file update for rpmsg tty driver that came in 5.16-rc1

   - vgacon fix for reported problem

  All of these, except for the 8250_bcm7271 fix have been in linux-next
  with no reported problem. The 8250_bcm7271 fix was added to the tree
  on Friday so no chance to be linux-next yet. But it should be fine as
  the affected developers submitted it"

* tag 'tty-5.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: 8250_bcm7271: UART errors after resuming from S2
  serial: 8250_pci: rewrite pericom_do_set_divisor()
  serial: 8250_pci: Fix ACCES entries in pci_serial_quirks array
  serial: 8250: Fix RTS modem control while in rs485 mode
  Revert "tty: serial: fsl_lpuart: drop earlycon entry for i.MX8QXP"
  serial: tegra: Change lower tolerance baud rate limit for tegra20 and tegra30
  serial: liteuart: relax compile-test dependencies
  serial: liteuart: fix minor-number leak on probe errors
  serial: liteuart: fix use-after-free and memleak on unbind
  serial: liteuart: Fix NULL pointer dereference in ->remove()
  vgacon: Propagate console boot parameters before calling `vc_resize'
  tty: serial: msm_serial: Deactivate RX DMA for polling support
  serial: pl011: Add ACPI SBSA UART match id
  serial: core: fix transmit-buffer reset and memleak
  MAINTAINERS: Add rpmsg tty driver maintainer
2021-12-05 09:13:20 -08:00
Linus Torvalds
7587a4a5a4 - Prevent a tick storm when a dedicated timekeeper CPU in nohz_full
mode runs for prolonged periods with interrupts disabled and ends up
 programming the next tick in the past, leading to that storm
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Merge tag 'timers_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fix from Borislav Petkov:

 - Prevent a tick storm when a dedicated timekeeper CPU in nohz_full
   mode runs for prolonged periods with interrupts disabled and ends up
   programming the next tick in the past, leading to that storm

* tag 'timers_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers/nohz: Last resort update jiffies on nohz_full IRQ entry
2021-12-05 08:58:52 -08:00
Linus Torvalds
1d213767dc - Properly init uclamp_flags of a runqueue, on first enqueuing
- Fix preempt= callback return values
 
 - Correct utime/stime resource usage reporting on nohz_full to return
 the proper times instead of shorter ones
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Merge tag 'sched_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Borislav Petkov:

 - Properly init uclamp_flags of a runqueue, on first enqueuing

 - Fix preempt= callback return values

 - Correct utime/stime resource usage reporting on nohz_full to return
   the proper times instead of shorter ones

* tag 'sched_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/uclamp: Fix rq->uclamp_max not set on first enqueue
  preempt/dynamic: Fix setup_preempt_mode() return value
  sched/cputime: Fix getrusage(RUSAGE_THREAD) with nohz_full
2021-12-05 08:53:31 -08:00
Linus Torvalds
f5d54a42d3 - Fix a couple of SWAPGS fencing issues in the x86 entry code
- Use the proper operand types in __{get,put}_user() to prevent
 truncation in SEV-ES string io
 
 - Make sure the kernel mappings are present in trampoline_pgd in order
 to prevent any potential accesses to unmapped memory after switching to
 it
 
 - Fix a trivial list corruption in objtool's pv_ops validation
 
 - Disable the clocksource watchdog for TSC on platforms which claim
 that the TSC is constant, doesn't stop in sleep states, CPU has TSC
 adjust and the number of sockets of the platform are max 2, to prevent
 erroneous markings of the TSC as unstable.
 
 - Make sure TSC adjust is always checked not only when going idle
 
 - Prevent a stack leak by initializing struct _fpx_sw_bytes properly in
 the FPU code
 
 - Fix INTEL_FAM6_RAPTORLAKE define naming to adhere to the convention
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Merge tag 'x86_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:

 - Fix a couple of SWAPGS fencing issues in the x86 entry code

 - Use the proper operand types in __{get,put}_user() to prevent
   truncation in SEV-ES string io

 - Make sure the kernel mappings are present in trampoline_pgd in order
   to prevent any potential accesses to unmapped memory after switching
   to it

 - Fix a trivial list corruption in objtool's pv_ops validation

 - Disable the clocksource watchdog for TSC on platforms which claim
   that the TSC is constant, doesn't stop in sleep states, CPU has TSC
   adjust and the number of sockets of the platform are max 2, to
   prevent erroneous markings of the TSC as unstable.

 - Make sure TSC adjust is always checked not only when going idle

 - Prevent a stack leak by initializing struct _fpx_sw_bytes properly in
   the FPU code

 - Fix INTEL_FAM6_RAPTORLAKE define naming to adhere to the convention

* tag 'x86_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/xen: Add xenpv_restore_regs_and_return_to_usermode()
  x86/entry: Use the correct fence macro after swapgs in kernel CR3
  x86/entry: Add a fence for kernel entry SWAPGS in paranoid_entry()
  x86/sev: Fix SEV-ES INS/OUTS instructions for word, dword, and qword
  x86/64/mm: Map all kernel memory into trampoline_pgd
  objtool: Fix pv_ops noinstr validation
  x86/tsc: Disable clocksource watchdog for TSC on qualified platorms
  x86/tsc: Add a timer to make sure TSC_adjust is always checked
  x86/fpu/signal: Initialize sw_bytes in save_xstate_epilog()
  x86/cpu: Drop spurious underscore from RAPTOR_LAKE #define
2021-12-05 08:43:35 -08:00
Linus Torvalds
90bf8d98b4 * Static analysis fix
* New SEV-ES protocol for communicating invalid VMGEXIT requests
 * Ensure APICv is considered inactive if there is no APIC
 * Fix reserved bits for AMD PerfEvtSeln register
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull more kvm fixes from Paolo Bonzini:

 - Static analysis fix

 - New SEV-ES protocol for communicating invalid VMGEXIT requests

 - Ensure APICv is considered inactive if there is no APIC

 - Fix reserved bits for AMD PerfEvtSeln register

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: SVM: Do not terminate SEV-ES guests on GHCB validation failure
  KVM: SEV: Fall back to vmalloc for SEV-ES scratch area if necessary
  KVM: SEV: Return appropriate error codes if SEV-ES scratch setup fails
  KVM: x86/mmu: Retry page fault if root is invalidated by memslot update
  KVM: VMX: Set failure code in prepare_vmcs02()
  KVM: ensure APICv is considered inactive if there is no APIC
  KVM: x86/pmu: Fix reserved bits for AMD PerfEvtSeln register
2021-12-05 08:25:33 -08:00
Tom Lendacky
ad5b353240 KVM: SVM: Do not terminate SEV-ES guests on GHCB validation failure
Currently, an SEV-ES guest is terminated if the validation of the VMGEXIT
exit code or exit parameters fails.

The VMGEXIT instruction can be issued from userspace, even though
userspace (likely) can't update the GHCB. To prevent userspace from being
able to kill the guest, return an error through the GHCB when validation
fails rather than terminating the guest. For cases where the GHCB can't be
updated (e.g. the GHCB can't be mapped, etc.), just return back to the
guest.

The new error codes are documented in the lasest update to the GHCB
specification.

Fixes: 291bd20d5d ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <b57280b5562893e2616257ac9c2d4525a9aeeb42.1638471124.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-05 03:02:04 -05:00
Sean Christopherson
a655276a59 KVM: SEV: Fall back to vmalloc for SEV-ES scratch area if necessary
Use kvzalloc() to allocate KVM's buffer for SEV-ES's GHCB scratch area so
that KVM falls back to __vmalloc() if physically contiguous memory isn't
available.  The buffer is purely a KVM software construct, i.e. there's
no need for it to be physically contiguous.

Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211109222350.2266045-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-05 03:02:03 -05:00
Sean Christopherson
75236f5f22 KVM: SEV: Return appropriate error codes if SEV-ES scratch setup fails
Return appropriate error codes if setting up the GHCB scratch area for an
SEV-ES guest fails.  In particular, returning -EINVAL instead of -ENOMEM
when allocating the kernel buffer could be confusing as userspace would
likely suspect a guest issue.

Fixes: 8f423a80d2 ("KVM: SVM: Support MMIO for an SEV-ES guest")
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211109222350.2266045-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-05 03:02:03 -05:00
Linus Torvalds
79a7216204 Fixes for 5.16-rc3:
- Remove an unnecessary (and backwards) rename flags check that
    duplicates a VFS level check.
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Merge tag 'xfs-5.16-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fix from Darrick Wong:
 "Remove an unnecessary (and backwards) rename flags check that
  duplicates a VFS level check"

* tag 'xfs-5.16-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: remove incorrect ASSERT in xfs_rename
2021-12-04 17:22:53 -08:00
Linus Torvalds
23b55d673d 3 SMB3 multichannel/fscache fixes and a DFS fix
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Merge tag '5.16-rc3-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "Three SMB3 multichannel/fscache fixes and a DFS fix.

  In testing multichannel reconnect scenarios recently various problems
  with the cifs.ko implementation of fscache were found (e.g. incorrect
  initialization of fscache cookies in some cases)"

* tag '5.16-rc3-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: avoid use of dstaddr as key for fscache client cookie
  cifs: add server conn_id to fscache client cookie
  cifs: wait for tcon resource_id before getting fscache super
  cifs: fix missed refcounting of ipc tcon
2021-12-04 13:43:52 -08:00
Helge Deller
afdb4a5b1d parisc: Mark cr16 CPU clocksource unstable on all SMP machines
In commit c8c3735997 ("parisc: Enhance detection of synchronous cr16
clocksources") I assumed that CPUs on the same physical core are syncronous.
While booting up the kernel on two different C8000 machines, one with a
dual-core PA8800 and one with a dual-core PA8900 CPU, this turned out to be
wrong. The symptom was that I saw a jump in the internal clocks printed to the
syslog and strange overall behaviour.  On machines which have 4 cores (2
dual-cores) the problem isn't visible, because the current logic already marked
the cr16 clocksource unstable in this case.

This patch now marks the cr16 interval timers unstable if we have more than one
CPU in the system, and it fixes this issue.

Fixes: c8c3735997 ("parisc: Enhance detection of synchronous cr16 clocksources")
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.15+
2021-12-04 21:36:04 +01:00
Helge Deller
0f9fee4cde parisc: Fix "make install" on newer debian releases
On newer debian releases the debian-provided "installkernel" script is
installed in /usr/sbin. Fix the kernel install.sh script to look for the
script in this directory as well.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v3.13+
2021-12-04 21:36:04 +01:00