fscache: Move fscache_cookies_seq_ops specific code under CONFIG_PROC_FS

fscache_cookies_seq_ops is only used in proc.c that is compiled under
enabled CONFIG_PROC_FS, so move related code under this

fscache: Move fscache_cookies_seq_ops specific code under CONFIG_PROC_FS

fscache_cookies_seq_ops is only used in proc.c that is compiled under
enabled CONFIG_PROC_FS, so move related code under this config. The
same case exsits in internal.h.

Also, make fscache_lru_cookie_timeout static due to no user outside
of cookie.c.

Signed-off-by: Yue Hu <huyue2@coolpad.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://listman.redhat.com/archives/linux-cachefs/2022-April/006649.html # v1

show more ...

fscache: export fscache_end_operation()

Export fscache_end_operation() to avoid code duplication.

Besides, considering the paired fscache_begin_read_operation() is
already exported, it shall make s

fscache: export fscache_end_operation()

Export fscache_end_operation() to avoid code duplication.

Besides, considering the paired fscache_begin_read_operation() is
already exported, it shall make sense to also export
fscache_end_operation().

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
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/20220302125134.131039-2-jefflexu@linux.alibaba.com/ # Jeffle's v4
Link: https://lore.kernel.org/r/164622971432.3564931.12184135678781328146.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/164678190346.1200972.7453733431978569479.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692888334.2099075.5166283293894267365.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/20220316131723.111553-2-jefflexu@linux.alibaba.com/ # v5

show more ...

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

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

show more ...

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

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

show more ...

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,

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

show more ...

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 o

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

show more ...

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
remo

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

show more ...

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:

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

show more ...

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_beg

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

show more ...

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

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

show more ...

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 object

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

show more ...

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:

str

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

show more ...

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 a

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

show more ...

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
d

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

show more ...

fscache: Use refcount_t for the cookie refcount instead of atomic_t

Use refcount_t for the fscache_cookie refcount instead of atomic_t and
rename the 'usage' member to 'ref' in such cases. The trac

fscache: Use refcount_t for the cookie refcount instead of atomic_t

Use refcount_t for the fscache_cookie refcount instead of atomic_t and
rename the 'usage' member to 'ref' in such cases. The tracepoints that
reference it change from showing "u=%d" to "r=%d".

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431204358.2908479.8006938388213098079.stgit@warthog.procyon.org.uk/

show more ...

fscache: Fix fscache_cookie_put() to not deref after dec

fscache_cookie_put() accesses the cookie it has just put inside the
tracepoint that monitors the change - but this is something it's not
allo

fscache: Fix fscache_cookie_put() to not deref after dec

fscache_cookie_put() accesses the cookie it has just put inside the
tracepoint that monitors the change - but this is something it's not
allowed to do if we didn't reduce the count to zero.

Fix this by dropping most of those values from the tracepoint and grabbing
the cookie debug ID before doing the dec.

Also take the opportunity to switch over the usage and where arguments on
the tracepoint to put the reason last.

Fixes: a18feb55769b ("fscache: Add tracepoints")
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431203107.2908479.3259582550347000088.stgit@warthog.procyon.org.uk/

show more ...

fscache: Fix cookie key hashing

The current hash algorithm used for hashing cookie keys is really bad,
producing almost no dispersion (after a test kernel build, ~30000 files
were split over just 18

fscache: Fix cookie key hashing

The current hash algorithm used for hashing cookie keys is really bad,
producing almost no dispersion (after a test kernel build, ~30000 files
were split over just 18 out of the 32768 hash buckets).

Borrow the full_name_hash() hash function into fscache to do the hashing
for cookie keys and, in the future, volume keys.

I don't want to use full_name_hash() as-is because I want the hash value to
be consistent across arches and over time as the hash value produced may
get used on disk.

I can also optimise parts of it away as the key will always be a padded
array of aligned 32-bit words.

Fixes: ec0328e46d6e ("fscache: Maintain a catalogue of allocated cookies")
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431201844.2908479.8293647220901514696.stgit@warthog.procyon.org.uk/

show more ...

fscache: Remove the object list procfile

Remove the object list procfile from fscache as objects will become
entirely internal to the cache.

Signed-off-by: David Howells <dhowells@redhat.com>
Revie

fscache: Remove the object list procfile

Remove the object list procfile from fscache as objects will become
entirely internal to the cache.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431198332.2908479.5847286163455099669.stgit@warthog.procyon.org.uk/

show more ...

fscache, cachefiles: Remove the histogram stuff

Remove the histogram stuff as it's mostly going to be outdated.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@

fscache, cachefiles: Remove the histogram stuff

Remove the histogram stuff as it's mostly going to be outdated.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431195953.2908479.16770977195634296638.stgit@warthog.procyon.org.uk/

show more ...

fscache: Procfile to display cookies

Add /proc/fs/fscache/cookies to display active cookies.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: lin

fscache: Procfile to display cookies

Add /proc/fs/fscache/cookies to display active cookies.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/158861211871.340223.7223853943667440807.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/159465771021.1376105.6933857529128238020.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/160588460994.3465195.16963417803501149328.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/162431194785.2908479.786917990782538164.stgit@warthog.procyon.org.uk/

show more ...

fscache, cachefiles: Add alternate API to use kiocb for read/write to cache

Add an alternate API by which the cache can be accessed through a kiocb,
doing async DIO, rather than using the current AP

fscache, cachefiles: Add alternate API to use kiocb for read/write to cache

Add an alternate API by which the cache can be accessed through a kiocb,
doing async DIO, rather than using the current API that tells the cache
where all the pages are.

The new API is intended to be used in conjunction with the netfs helper
library. A filesystem must pick one or the other and not mix them.

Filesystems wanting to use the new API must #define FSCACHE_USE_NEW_IO_API
before #including the header. This prevents them from continuing to use
the old API at the same time as there are incompatibilities in how the
PG_fscache page bit is used.

Changes:
v6:
- Provide a routine to shape a write so that the start and length can be
aligned for DIO[3].

v4:
- Use the vfs_iocb_iter_read/write() helpers[1]
- Move initial definition of fscache_begin_read_operation() here.
- Remove a commented-out line[2]
- Combine ki->term_func calls in cachefiles_read_complete()[2].
- Remove explicit NULL initialiser[2].
- Remove extern on func decl[2].
- Put in param names on func decl[2].
- Remove redundant else[2].
- Fill out the kdoc comment for fscache_begin_read_operation().
- Rename fs/fscache/page2.c to io.c to match later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: Christoph Hellwig <hch@lst.de>
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20210216102614.GA27555@lst.de/ [1]
Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [2]
Link: https://lore.kernel.org/r/161781047695.463527.7463536103593997492.stgit@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/161118142558.1232039.17993829899588971439.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161037850.2537118.8819808229350326503.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340402057.1303470.8038373593844486698.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539545919.286939.14573472672781434757.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653801477.2770958.10543270629064934227.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789084517.6155.12799689829859169640.stgit@warthog.procyon.org.uk/ # v6

show more ...

fscache: Fix cookie key hashing

[ Upstream commit 35b72573e977ed6b18b094136a4fa3e0ffb13603 ]

The current hash algorithm used for hashing cookie keys is really bad,
producing almost no dispersion (a

fscache: Fix cookie key hashing

[ Upstream commit 35b72573e977ed6b18b094136a4fa3e0ffb13603 ]

The current hash algorithm used for hashing cookie keys is really bad,
producing almost no dispersion (after a test kernel build, ~30000 files
were split over just 18 out of the 32768 hash buckets).

Borrow the full_name_hash() hash function into fscache to do the hashing
for cookie keys and, in the future, volume keys.

I don't want to use full_name_hash() as-is because I want the hash value to
be consistent across arches and over time as the hash value produced may
get used on disk.

I can also optimise parts of it away as the key will always be a padded
array of aligned 32-bit words.

Fixes: ec0328e46d6e ("fscache: Maintain a catalogue of allocated cookies")
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431201844.2908479.8293647220901514696.stgit@warthog.procyon.org.uk/
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

proc: convert everything to "struct proc_ops"

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

llseek => proc_lseek
unlocked_ioctl => proc_ioctl

proc: convert everything to "struct proc_ops"

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

llseek => proc_lseek
unlocked_ioctl => proc_ioctl

xxx => proc_xxx

delete ".owner = THIS_MODULE" line

[akpm@linux-foundation.org: fix drivers/isdn/capi/kcapi_proc.c]
[sfr@canb.auug.org.au: fix kernel/sched/psi.c]
Link: http://lkml.kernel.org/r/20200122180545.36222f50@canb.auug.org.au
Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

fscache: Fix incomplete initialisation of inline key space

The inline key in struct rxrpc_cookie is insufficiently initialized,
zeroing only 3 of the 4 slots, therefore an index_key_len between 13 a

fscache: Fix incomplete initialisation of inline key space

The inline key in struct rxrpc_cookie is insufficiently initialized,
zeroing only 3 of the 4 slots, therefore an index_key_len between 13 and 15
bytes will end up hashing uninitialized memory because the memcpy only
partially fills the last buf[] element.

Fix this by clearing fscache_cookie objects on allocation rather than using
the slab constructor to initialise them. We're going to pretty much fill
in the entire struct anyway, so bringing it into our dcache writably
shouldn't incur much overhead.

This removes the need to do clearance in fscache_set_key() (where we aren't
doing it correctly anyway).

Also, we don't need to set cookie->key_len in fscache_set_key() as we
already did it in the only caller, so remove that.

Fixes: ec0328e46d6e ("fscache: Maintain a catalogue of allocated cookies")
Reported-by: syzbot+a95b989b2dde8e806af8@syzkaller.appspotmail.com
Reported-by: Eric Sandeen <sandeen@redhat.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...