cachefiles: flush all requests after setting CACHEFILES_DEAD

[ Upstream commit 85e833cd7243bda7285492b0653c3abb1e2e757b ]

In ondemand mode, when the daemon is processing an open request, if the
ker

cachefiles: flush all requests after setting CACHEFILES_DEAD

[ Upstream commit 85e833cd7243bda7285492b0653c3abb1e2e757b ]

In ondemand mode, when the daemon is processing an open request, if the
kernel flags the cache as CACHEFILES_DEAD, the cachefiles_daemon_write()
will always return -EIO, so the daemon can't pass the copen to the kernel.
Then the kernel process that is waiting for the copen triggers a hung_task.

Since the DEAD state is irreversible, it can only be exited by closing
/dev/cachefiles. Therefore, after calling cachefiles_io_error() to mark
the cache as CACHEFILES_DEAD, if in ondemand mode, flush all requests to
avoid the above hungtask. We may still be able to read some of the cached
data before closing the fd of /dev/cachefiles.

Note that this relies on the patch that adds reference counting to the req,
otherwise it may UAF.

Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240522114308.2402121-12-libaokun@huaweicloud.com
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cachefiles: add restore command to recover inflight ondemand read requests

[ Upstream commit e73fa11a356ca0905c3cc648eaacc6f0f2d2c8b3 ]

Previously, in ondemand read scenario, if the anonymous fd wa

cachefiles: add restore command to recover inflight ondemand read requests

[ Upstream commit e73fa11a356ca0905c3cc648eaacc6f0f2d2c8b3 ]

Previously, in ondemand read scenario, if the anonymous fd was closed by
user daemon, inflight and subsequent read requests would return EIO.
As long as the device connection is not released, user daemon can hold
and restore inflight requests by setting the request flag to
CACHEFILES_REQ_NEW.

Suggested-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
Link: https://lore.kernel.org/r/20231120041422.75170-6-zhujia.zj@bytedance.com
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stable-dep-of: 4b4391e77a6b ("cachefiles: defer exposing anon_fd until after copy_to_user() succeeds")
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cachefiles: remove requests from xarray during flushing requests

[ Upstream commit 0fc75c5940fa634d84e64c93bfc388e1274ed013 ]

Even with CACHEFILES_DEAD set, we can still read the requests, so in th

cachefiles: remove requests from xarray during flushing requests

[ Upstream commit 0fc75c5940fa634d84e64c93bfc388e1274ed013 ]

Even with CACHEFILES_DEAD set, we can still read the requests, so in the
following concurrency the request may be used after it has been freed:

mount | daemon_thread1 | daemon_thread2
------------------------------------------------------------
cachefiles_ondemand_init_object
cachefiles_ondemand_send_req
REQ_A = kzalloc(sizeof(*req) + data_len)
wait_for_completion(&REQ_A->done)
cachefiles_daemon_read
cachefiles_ondemand_daemon_read
// close dev fd
cachefiles_flush_reqs
complete(&REQ_A->done)
kfree(REQ_A)
xa_lock(&cache->reqs);
cachefiles_ondemand_select_req
req->msg.opcode != CACHEFILES_OP_READ
// req use-after-free !!!
xa_unlock(&cache->reqs);
xa_destroy(&cache->reqs)

Hence remove requests from cache->reqs when flushing them to avoid
accessing freed requests.

Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240522114308.2402121-3-libaokun@huaweicloud.com
Acked-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cachefiles: flush all requests after setting CACHEFILES_DEAD

[ Upstream commit 85e833cd7243bda7285492b0653c3abb1e2e757b ]

In ondemand mode, when the daemon is processing an open request, if the
ker

cachefiles: flush all requests after setting CACHEFILES_DEAD

[ Upstream commit 85e833cd7243bda7285492b0653c3abb1e2e757b ]

In ondemand mode, when the daemon is processing an open request, if the
kernel flags the cache as CACHEFILES_DEAD, the cachefiles_daemon_write()
will always return -EIO, so the daemon can't pass the copen to the kernel.
Then the kernel process that is waiting for the copen triggers a hung_task.

Since the DEAD state is irreversible, it can only be exited by closing
/dev/cachefiles. Therefore, after calling cachefiles_io_error() to mark
the cache as CACHEFILES_DEAD, if in ondemand mode, flush all requests to
avoid the above hungtask. We may still be able to read some of the cached
data before closing the fd of /dev/cachefiles.

Note that this relies on the patch that adds reference counting to the req,
otherwise it may UAF.

Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240522114308.2402121-12-libaokun@huaweicloud.com
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cachefiles: add restore command to recover inflight ondemand read requests

[ Upstream commit e73fa11a356ca0905c3cc648eaacc6f0f2d2c8b3 ]

Previously, in ondemand read scenario, if the anonymous fd wa

cachefiles: add restore command to recover inflight ondemand read requests

[ Upstream commit e73fa11a356ca0905c3cc648eaacc6f0f2d2c8b3 ]

Previously, in ondemand read scenario, if the anonymous fd was closed by
user daemon, inflight and subsequent read requests would return EIO.
As long as the device connection is not released, user daemon can hold
and restore inflight requests by setting the request flag to
CACHEFILES_REQ_NEW.

Suggested-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
Link: https://lore.kernel.org/r/20231120041422.75170-6-zhujia.zj@bytedance.com
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stable-dep-of: 4b4391e77a6b ("cachefiles: defer exposing anon_fd until after copy_to_user() succeeds")
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cachefiles: remove requests from xarray during flushing requests

[ Upstream commit 0fc75c5940fa634d84e64c93bfc388e1274ed013 ]

Even with CACHEFILES_DEAD set, we can still read the requests, so in th

cachefiles: remove requests from xarray during flushing requests

[ Upstream commit 0fc75c5940fa634d84e64c93bfc388e1274ed013 ]

Even with CACHEFILES_DEAD set, we can still read the requests, so in the
following concurrency the request may be used after it has been freed:

mount | daemon_thread1 | daemon_thread2
------------------------------------------------------------
cachefiles_ondemand_init_object
cachefiles_ondemand_send_req
REQ_A = kzalloc(sizeof(*req) + data_len)
wait_for_completion(&REQ_A->done)
cachefiles_daemon_read
cachefiles_ondemand_daemon_read
// close dev fd
cachefiles_flush_reqs
complete(&REQ_A->done)
kfree(REQ_A)
xa_lock(&cache->reqs);
cachefiles_ondemand_select_req
req->msg.opcode != CACHEFILES_OP_READ
// req use-after-free !!!
xa_unlock(&cache->reqs);
xa_destroy(&cache->reqs)

Hence remove requests from cache->reqs when flushing them to avoid
accessing freed requests.

Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240522114308.2402121-3-libaokun@huaweicloud.com
Acked-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cachefiles: fix memory leak in cachefiles_add_cache()

commit e21a2f17566cbd64926fb8f16323972f7a064444 upstream.

The following memory leak was reported after unbinding /dev/cachefiles:

============

cachefiles: fix memory leak in cachefiles_add_cache()

commit e21a2f17566cbd64926fb8f16323972f7a064444 upstream.

The following memory leak was reported after unbinding /dev/cachefiles:

==================================================================
unreferenced object 0xffff9b674176e3c0 (size 192):
comm "cachefilesd2", pid 680, jiffies 4294881224
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc ea38a44b):
[<ffffffff8eb8a1a5>] kmem_cache_alloc+0x2d5/0x370
[<ffffffff8e917f86>] prepare_creds+0x26/0x2e0
[<ffffffffc002eeef>] cachefiles_determine_cache_security+0x1f/0x120
[<ffffffffc00243ec>] cachefiles_add_cache+0x13c/0x3a0
[<ffffffffc0025216>] cachefiles_daemon_write+0x146/0x1c0
[<ffffffff8ebc4a3b>] vfs_write+0xcb/0x520
[<ffffffff8ebc5069>] ksys_write+0x69/0xf0
[<ffffffff8f6d4662>] do_syscall_64+0x72/0x140
[<ffffffff8f8000aa>] entry_SYSCALL_64_after_hwframe+0x6e/0x76
==================================================================

Put the reference count of cache_cred in cachefiles_daemon_unbind() to
fix the problem. And also put cache_cred in cachefiles_add_cache() error
branch to avoid memory leaks.

Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem")
CC: stable@vger.kernel.org
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240217081431.796809-1-libaokun1@huawei.com
Acked-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

cachefiles: enable on-demand read mode

Enable on-demand read mode by adding an optional parameter to the "bind"
command.

On-demand mode will be turned on when this parameter is "ondemand", i.e.
"bi

cachefiles: enable on-demand read mode

Enable on-demand read mode by adding an optional parameter to the "bind"
command.

On-demand mode will be turned on when this parameter is "ondemand", i.e.
"bind ondemand". Otherwise cachefiles will work in the original mode.

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220509074028.74954-7-jefflexu@linux.alibaba.com
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

show more ...

cachefiles: unbind cachefiles gracefully in on-demand mode

Add a refcount to avoid the deadlock in on-demand read mode. The
on-demand read mode will pin the corresponding cachefiles object for
each

cachefiles: unbind cachefiles gracefully in on-demand mode

Add a refcount to avoid the deadlock in on-demand read mode. The
on-demand read mode will pin the corresponding cachefiles object for
each anonymous fd. The cachefiles object is unpinned when the anonymous
fd gets closed. When the user daemon exits and the fd of
"/dev/cachefiles" device node gets closed, it will wait for all
cahcefiles objects getting withdrawn. Then if there's any anonymous fd
getting closed after the fd of the device node, the user daemon will
hang forever, waiting for all objects getting withdrawn.

To fix this, add a refcount indicating if there's any object pinned by
anonymous fds. The cachefiles cache gets unbound and withdrawn when the
refcount is decreased to 0. It won't change the behaviour of the
original mode, in which case the cachefiles cache gets unbound and
withdrawn as long as the fd of the device node gets closed.

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220509074028.74954-4-jefflexu@linux.alibaba.com
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

show more ...

cachefiles: notify the user daemon when looking up cookie

Fscache/CacheFiles used to serve as a local cache for a remote
networking fs. A new on-demand read mode will be introduced for
CacheFiles, w

cachefiles: notify the user daemon when looking up cookie

Fscache/CacheFiles used to serve as a local cache for a remote
networking fs. A new on-demand read mode will be introduced for
CacheFiles, which can boost the scenario where on-demand read semantics
are needed, e.g. container image distribution.

The essential difference between these two modes is seen when a cache
miss occurs: In the original mode, the netfs will fetch the data from
the remote server and then write it to the cache file; in on-demand
read mode, fetching the data and writing it into the cache is delegated
to a user daemon.

As the first step, notify the user daemon when looking up cookie. In
this case, an anonymous fd is sent to the user daemon, through which the
user daemon can write the fetched data to the cache file. Since the user
daemon may move the anonymous fd around, e.g. through dup(), an object
ID uniquely identifying the cache file is also attached.

Also add one advisory flag (FSCACHE_ADV_WANT_CACHE_SIZE) suggesting that
the cache file size shall be retrieved at runtime. This helps the
scenario where one cache file contains multiple netfs files, e.g. for
the purpose of deduplication. In this case, netfs itself has no idea the
size of the cache file, whilst the user daemon should give the hint on
it.

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220509074028.74954-3-jefflexu@linux.alibaba.com
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

show more ...

cachefiles: set default tag name if it's unspecified

fscache_acquire_cache() requires a non-empty name, while 'tag <name>'
command is optional for cachefilesd.

Thus set default tag name if it's uns

cachefiles: set default tag name if it's unspecified

fscache_acquire_cache() requires a non-empty name, while 'tag <name>'
command is optional for cachefilesd.

Thus set default tag name if it's unspecified to avoid the regression of
cachefilesd. The logic is the same with that before rewritten.

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/164251399914.3435901.4761991152407411408.stgit@warthog.procyon.org.uk/ # v1

show more ...

fscache, cachefiles: Display stats of no-space events

Add stat counters of no-space events that caused caching not to happen and
display in /proc/fs/fscache/stats.

Signed-off-by: David Howells <dho

fscache, cachefiles: Display stats of no-space events

Add stat counters of no-space events that caused caching not to happen and
display in /proc/fs/fscache/stats.

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/163819653216.215744.17210522251617386509.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906958369.143852.7257100711818401748.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967166917.1823006.14842444049198947892.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021566184.640689.4417328329632709265.stgit@warthog.procyon.org.uk/ # v4

show more ...

cachefiles: Allow cachefiles to actually function

Remove the block that allowed cachefiles to be compiled but prevented it
from actually starting a cache.

Signed-off-by: David Howells <dhowells@red

cachefiles: Allow cachefiles to actually function

Remove the block that allowed cachefiles to be compiled but prevented it
from actually starting 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/163819649497.215744.2872504990762846767.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906956491.143852.4951522864793559189.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967165374.1823006.14248189932202373809.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021564379.640689.7921380491176827442.stgit@warthog.procyon.org.uk/ # v4

show more ...

cachefiles: Implement backing file wrangling

Implement the wrangling of backing files, including the following pieces:

(1) Lookup and creation of a file on disk, using a tmpfile if the file
i

cachefiles: Implement backing file wrangling

Implement the wrangling of backing files, including the following pieces:

(1) Lookup and creation of a file on disk, using a tmpfile if the file
isn't yet present. The file is then opened, sized for DIO and the
file handle is attached to the cachefiles_object struct. The inode is
marked to indicate that it's in use by a kernel service.

(2) Invalidation of an object, creating a tmpfile and switching the file
pointer in the cachefiles object.

(3) Committing a file to disk, including setting the coherency xattr on it
and, if necessary, creating a hard link to it.

Note that this would be a good place to use Omar Sandoval's vfs_link()
with AT_LINK_REPLACE[1] as I may have to unlink an old file before I
can link a tmpfile into place.

(4) Withdrawal of open objects when a cache is being withdrawn or a cookie
is relinquished. This involves committing or discarding the file.

Changes
=======
ver #2:
- Fix logging of wrong error[1].

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/20211203094950.GA2480@kili/ [1]
Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4

show more ...

cachefiles: Implement culling daemon commands

Implement the ability for the userspace daemon to try and cull a file or
directory in the cache. Two daemon commands are implemented:

(1) The "inuse"

cachefiles: Implement culling daemon commands

Implement the ability for the userspace daemon to try and cull a file or
directory in the cache. Two daemon commands are implemented:

(1) The "inuse" command. This queries if a file is in use or whether it
can be deleted. It checks the S_KERNEL_FILE flag on the inode
referred to by the specified filename.

(2) The "cull" command. This asks for a file or directory to be removed,
where removal means either unlinking it or moving it to the graveyard
directory for userspace to dismantle.

Changes
=======
ver #2:
- Fix logging of wrong error[1].
- Need to unmark an inode we've moved to the graveyard before unlocking.

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/20211203094950.GA2480@kili/ [1]
Link: https://lore.kernel.org/r/163819643179.215744.13641580295708315695.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906945705.143852.8177595531814485350.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967155792.1823006.1088936326902550910.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021555037.640689.9472627499842585255.stgit@warthog.procyon.org.uk/ # v4

show more ...

cachefiles: Implement volume support

Implement support for creating the directory layout for a volume on disk
and setting up and withdrawing volume caching.

Each volume has a directory named for th

cachefiles: Implement volume support

Implement support for creating the directory layout for a volume on disk
and setting up and withdrawing volume caching.

Each volume has a directory named for the volume key under the root of the
cache (prefixed with an 'I' to indicate to cachefilesd that it's an index)
and then creates a bunch of hash bucket subdirectories under that (named as
'@' plus a hex number) in which cookie files will be created.

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/163819635314.215744.13081522301564537723.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906936397.143852.17788457778396467161.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967143860.1823006.7185205806080225038.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021545212.640689.5064821392307582927.stgit@warthog.procyon.org.uk/ # v4

show more ...

cachefiles: Implement cache registration and withdrawal

Do the following:

(1) Fill out cachefiles_daemon_add_cache() so that it sets up the cache
directories and registers the cache with cach

cachefiles: Implement cache registration and withdrawal

Do the following:

(1) Fill out cachefiles_daemon_add_cache() so that it sets up the cache
directories and registers the cache with cachefiles.

(2) Add a function to do the top-level part of cache withdrawal and
unregistration.

(3) Add a function to sync 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/163819633175.215744.10857127598041268340.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906935445.143852.15545194974036410029.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967142904.1823006.244055483596047072.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021543872.640689.14370017789605073222.stgit@warthog.procyon.org.uk/ # v4

show more ...

cachefiles: Provide a function to check how much space there is

Provide a function to check how much space there is. This also flips the
state on the cache and will signal the daemon to inform it o

cachefiles: Provide a function to check how much space there is

Provide a function to check how much space there is. This also flips the
state on the cache and will signal the daemon to inform it of the change
and to ask it to do some culling if necessary.

We will also need to subtract the amount of data currently being written to
the cache (cache->b_writing) from the amount of available space to avoid
hitting ENOSPC accidentally.

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/163819629322.215744.13457425294680841213.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906930100.143852.1681026700865762069.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967140058.1823006.7781243664702837128.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021539957.640689.12477177372616805706.stgit@warthog.procyon.org.uk/ # v4

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cachefiles: Register a miscdev and parse commands over it

Register a misc device with which to talk to the daemon. The misc device
holds a cache set up through it around and closing the device kill

cachefiles: Register a miscdev and parse commands over it

Register a misc device with which to talk to the daemon. The misc device
holds a cache set up through it around and closing the device kills the
cache.

cachefilesd communicates with the kernel by passing it single-line text
commands. Parse these and use them to parameterise the cache state. This
does not implement the command to actually bring a cache online. That's
left for later.

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/163819628388.215744.17712097043607299608.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906929128.143852.14065207858943654011.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967139085.1823006.3514846391807454287.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021538400.640689.9172006906288062041.stgit@warthog.procyon.org.uk/ # v4

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36

Based on 1 normalized pattern(s):

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

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36

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 licence as published by
the free software foundation either version 2 of the licence 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 114 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAN

vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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fs: annotate ->poll() instances

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

CacheFiles: Provide read-and-reset release counters for cachefilesd

Provide read-and-reset objects- and blocks-released counters for cachefilesd
to use to work out whether there's anything new that

CacheFiles: Provide read-and-reset release counters for cachefilesd

Provide read-and-reset objects- and blocks-released counters for cachefilesd
to use to work out whether there's anything new that can be culled.

One of the problems cachefilesd has is that if all the objects in the cache
are pinned by inodes lying dormant in the kernel inode cache, there isn't
anything for it to cull. In such a case, it just spins around walking the
filesystem tree and scanning for something to cull. This eats up a lot of
CPU time.

By telling cachefilesd if there have been any releases, the daemon can
sleep until there is the possibility of something to do.

cachefilesd finds this information by the following means:

(1) When the control fd is read, the kernel presents a list of values of
interest. "freleased=N" and "breleased=N" are added to this list to
indicate the number of files released and number of blocks released
since the last read call. At this point the counters are reset.

(2) POLLIN is signalled if the number of files released becomes greater
than 0.

Note that by 'released' it just means that the kernel has released its
interest in those files for the moment, not necessarily that the files
should be deleted from the cache.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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convert a bunch of open-coded instances of memdup_user_nul()

A _lot_ of ->write() instances were open-coding it; some are
converted to memdup_user_nul(), a lot more remain...

Signed-off-by: Al Viro

convert a bunch of open-coded instances of memdup_user_nul()

A _lot_ of ->write() instances were open-coding it; some are
converted to memdup_user_nul(), a lot more remain...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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Cachefiles: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions

Fix up the following scripted S_ISDIR/S_ISREG/S_ISLNK conversions (or lack
thereof) in cachefiles:

(1) Cachefiles mostly wants to us

Cachefiles: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions

Fix up the following scripted S_ISDIR/S_ISREG/S_ISLNK conversions (or lack
thereof) in cachefiles:

(1) Cachefiles mostly wants to use d_can_lookup() rather than d_is_dir() as
it doesn't want to deal with automounts in its cache.

(2) Coccinelle didn't find S_IS* expressions in ASSERT() statements in
cachefiles.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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