Jeff Layton [Mon, 13 Jul 2020 13:59:39 +0000 (09:59 -0400)]
ceph: add fscache writeback support
When updating the backing store from the pagecache (a'la writepage or
writepages), write to the cache first. This allows us to keep caching
files even when they are being written, as long as we have appropriate
caps.
Jeff Layton [Tue, 12 May 2020 18:24:02 +0000 (14:24 -0400)]
ceph: conversion to new fscache API
Now that the fscache API has been reworked and simplified, change ceph
over to use it.
With the old API, we would only instantiate a cookie when the file was
open for reads. Change it to instantiate the cookie when the inode is
instantiated and call use/unuse when the file is opened/closed.
Also, ensure we resize the cached data on truncates, and invalidate the
cache in response to the appropriate events. This will allow us to
plumb in write support later.
David Howells [Tue, 17 Nov 2020 15:56:59 +0000 (15:56 +0000)]
cifs: Support fscache indexing rewrite (untested)
Change the cifs filesystem to take account of the changes to fscache's
indexing rewrite and reenable caching in cifs.
The following changes have been made:
(1) The fscache_netfs struct is no more, and there's no need to register
the filesystem as a whole.
(2) The session cookie is now an fscache_volume cookie, allocated with
fscache_acquire_volume(). That takes three parameters: a string
representing the "volume" in the index, a string naming the cache to
use (or NULL) and a u64 that conveys coherency metadata for the
volume.
For cifs, I've made it render the volume name string as:
"cifs,<ipaddress>,<sharename>"
where the sharename has '/' characters replaced with ';'.
This probably needs rethinking a bit as the total name could exceed
the maximum filename component length.
Further, the coherency data is currently just set to 0. It needs
something else doing with it - I wonder if it would suffice simply to
sum the resource_id, vol_create_time and vol_serial_number or maybe
hash them.
(3) The fscache_cookie_def is no more and needed information is passed
directly to fscache_acquire_cookie(). The cache no longer calls back
into the filesystem, but rather metadata changes are indicated at
other times.
fscache_acquire_cookie() is passed the same keying and coherency
information as before.
(4) The functions to set/reset cookies are removed and
fscache_use_cookie() and fscache_unuse_cookie() are used instead.
fscache_use_cookie() is passed a flag to indicate if the cookie is
opened for writing. fscache_unuse_cookie() is passed updates for the
metadata if we changed it (ie. if the file was opened for writing).
These are called when the file is opened or closed.
(5) cifs_setattr_*() are made to call fscache_resize() to change the size
of the cache object.
(6) The functions to read and write data are stubbed out pending a
conversion to use netfslib.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: linux-cifs@vger.kernel.org
cc: linux-cachefs@redhat.com
Dave Wysochanski [Sat, 14 Nov 2020 18:43:54 +0000 (13:43 -0500)]
nfs: Convert to new fscache volume/cookie API
Change the nfs filesystem to support fscache's indexing rewrite and
reenable caching in nfs.
The following changes have been made:
(1) The fscache_netfs struct is no more, and there's no need to register
the filesystem as a whole.
(2) The session cookie is now an fscache_volume cookie, allocated with
fscache_acquire_volume(). That takes three parameters: a string
representing the "volume" in the index, a string naming the cache to
use (or NULL) and a u64 that conveys coherency metadata for the
volume.
For nfs, I've made it render the volume name string as:
(3) The fscache_cookie_def is no more and needed information is passed
directly to fscache_acquire_cookie(). The cache no longer calls back
into the filesystem, but rather metadata changes are indicated at
other times.
fscache_acquire_cookie() is passed the same keying and coherency
information as before.
(4) fscache_enable/disable_cookie() have been removed.
Call fscache_use_cookie() and fscache_unuse_cookie() when a file is
opened or closed to prevent a cache file from being culled and to keep
resources to hand that are needed to do I/O.
Unuse the cookie when a file is opened for writing. This is gated by
the NFS_INO_FSCACHE flag on the nfs_inode.
A better way might be to invalidate it with FSCACHE_INVAL_DIO_WRITE
which will keep it unused until all open files are closed.
(5) fscache_invalidate() now needs to be given uptodate auxiliary data and
a file size. It also takes a flag to indicate if this was due to a
DIO write.
(6) Call nfs_fscache_invalidate() with FSCACHE_INVAL_DIO_WRITE on a file
to which a DIO write is made.
(7) Call fscache_note_page_release() from nfs_release_page().
(8) Use a killable wait in nfs_vm_page_mkwrite() when waiting for
PG_fscache to be cleared.
(9) The functions to read and write data to/from the cache are stubbed out
pending a conversion to use netfslib.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com> Co-developed-by: David Howells <dhowells@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: Anna Schumaker <anna.schumaker@netapp.com>
cc: linux-nfs@vger.kernel.org
cc: linux-cachefs@redhat.com
David Howells [Wed, 18 Nov 2020 09:06:42 +0000 (09:06 +0000)]
9p: Copy local writes to the cache when writing to the server
When writing to the server from v9fs_vfs_writepage(), copy the data to the
cache object too.
To make this possible, the cookie must have its active users count
incremented when the page is dirtied and kept incremented until we manage
to clean up all the pages. This allows the writeback to take place after
the last file struct is released.
This is done by taking a use on the cookie in v9fs_set_page_dirty() if we
haven't already done so (controlled by the I_PINNING_FSCACHE_WB flag) and
dropping the pin in v9fs_write_inode() if __writeback_single_inode() clears
all the outstanding dirty pages (conveyed by the unpinned_fscache_wb flag
in the writeback_control struct).
Inode eviction must also clear the flag after truncating away all the
outstanding pages.
In the future this will be handled more gracefully by netfslib.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-cachefs@redhat.com
David Howells [Wed, 18 Nov 2020 09:06:42 +0000 (09:06 +0000)]
9p: Use fscache indexing rewrite and reenable caching
Change the 9p filesystem to take account of the changes to fscache's
indexing rewrite and reenable caching in 9p.
The following changes have been made:
(1) The fscache_netfs struct is no more, and there's no need to register
the filesystem as a whole.
(2) The session cookie is now an fscache_volume cookie, allocated with
fscache_acquire_volume(). That takes three parameters: a string
representing the "volume" in the index, a string naming the cache to
use (or NULL) and a u64 that conveys coherency metadata for the
volume.
For 9p, I've made it render the volume name string as:
"9p,<devname>,<cachetag>"
where the cachetag is replaced by the aname if it wasn't supplied.
This probably needs rethinking a bit as the aname can have slashes in
it. It might be better to hash the cachetag and use the hash or I
could substitute commas for the slashes or something.
(3) The fscache_cookie_def is no more and needed information is passed
directly to fscache_acquire_cookie(). The cache no longer calls back
into the filesystem, but rather metadata changes are indicated at
other times.
fscache_acquire_cookie() is passed the same keying and coherency
information as before.
(4) The functions to set/reset/flush cookies are removed and
fscache_use_cookie() and fscache_unuse_cookie() are used instead.
fscache_use_cookie() is passed a flag to indicate if the cookie is
opened for writing. fscache_unuse_cookie() is passed updates for the
metadata if we changed it (ie. if the file was opened for writing).
These are called when the file is opened or closed.
(5) wait_on_page_bit[_killable]() is replaced with the specific wait
functions for the bits waited upon.
(6) I've got rid of some of the 9p-specific cache helper functions and
called things like fscache_relinquish_cookie() directly as they'll
optimise away if v9fs_inode_cookie() returns an unconditional NULL
(which will be the case if CONFIG_9P_FSCACHE=n).
(7) v9fs_vfs_setattr() is made to call fscache_resize() to change the size
of the cache object.
Notes:
(A) We should call fscache_invalidate() if we detect that the server's
copy of a file got changed by a third party, but I don't know where to
do that. We don't need to do that when allocating the cookie as we
get a check-and-invalidate when we initially bind to the cache object.
(B) The copy-to-cache-on-writeback side of things will be handled in
separate patch.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-cachefs@redhat.com
David Howells [Thu, 6 Feb 2020 14:22:30 +0000 (14:22 +0000)]
afs: Copy local writes to the cache when writing to the server
When writing to the server from afs_writepage() or afs_writepages(), copy
the data to the cache object too.
To make this possible, the cookie must have its active users count
incremented when the page is dirtied and kept incremented until we manage
to clean up all the pages. This allows the writeback to take place after
the last file struct is released.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-cachefs@redhat.com
David Howells [Thu, 6 Feb 2020 14:22:21 +0000 (14:22 +0000)]
afs: Convert afs to use the new fscache API
Change the afs filesystem to support the new afs driver.
The following changes have been made:
(1) The fscache_netfs struct is no more, and there's no need to register
the filesystem as a whole. There's also no longer a cell cookie.
(2) The volume cookie is now an fscache_volume cookie, allocated with
fscache_acquire_volume(). This function takes three parameters: a
string representing the "volume" in the index, a string naming the
cache to use (or NULL) and a u64 that conveys coherency metadata for
the volume.
For afs, I've made it render the volume name string as:
"afs,<cell>,<volume_id>"
and the coherency data is currently 0.
(3) The fscache_cookie_def is no more and needed information is passed
directly to fscache_acquire_cookie(). The cache no longer calls back
into the filesystem, but rather metadata changes are indicated at
other times.
fscache_acquire_cookie() is passed the same keying and coherency
information as before, except that these are now stored in big endian
form instead of cpu endian. This makes the cache more copyable.
(4) fscache_use_cookie() and fscache_unuse_cookie() are called when a file
is opened or closed to prevent a cache file from being culled and to
keep resources to hand that are needed to do I/O.
fscache_use_cookie() is given an indication if the cache is likely to
be modified locally (e.g. the file is open for writing).
fscache_unuse_cookie() is given a coherency update if we had the file
open for writing and will update that.
(5) fscache_invalidate() is now given uptodate auxiliary data and a file
size. It can also take a flag to indicate if this was due to a DIO
write. This is wrapped into afs_fscache_invalidate() now for
convenience.
(6) fscache_resize() now gets called from the finalisation of
afs_setattr(), and afs_setattr() does use/unuse of the cookie around
the call to support this.
(7) fscache_note_page_release() is called from afs_release_page().
(8) Use a killable wait in nfs_vm_page_mkwrite() when waiting for
PG_fscache to be cleared.
Render the parts of the cookie key for an afs inode cookie as big endian.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-cachefs@redhat.com
David Howells [Mon, 14 Jun 2021 13:13:41 +0000 (14:13 +0100)]
afs: Fix afs_write_end() to handle len > page size
It is possible for the len argument to afs_write_end() to overrun the end
of the page (len is used to key the size of the page in afs_write_start()
when compound pages become a regular thing).
Fix afs_write_end() to correctly trim the write length so that it doesn't
exceed the end of the page.
Fixes: 3003bbd0697b ("afs: Use the netfs_write_begin() helper") Reported-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/162367682522.460125.5652091227576721609.stgit@warthog.procyon.org.uk/
David Howells [Mon, 14 Jun 2021 12:48:02 +0000 (13:48 +0100)]
afs: Handle len being extending over page end in write_begin/write_end
With transparent huge pages, in the future, write_begin() and write_end()
may be passed a length parameter that, in combination with the offset into
the page, exceeds the length of that page. This allows
grab_cache_page_write_begin() to better choose the size of THP to allocate.
Fix afs's functions to handle this by trimming the length as needed after
the page has been allocated.
[Removed the now-unnecessary index var; spotted by kernel test robot]
Fixes: e1b1240c1ff5 ("netfs: Add write_begin helper") Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/162367681795.460125.11729955608839747375.stgit@warthog.procyon.org.uk/
David Howells [Fri, 22 Oct 2021 08:17:58 +0000 (09:17 +0100)]
fscache, cachefiles: Display stat of culling events
Add a stat counter of culling events whereby the cache backend culls a file
to make space (when asked by cachefilesd in this case) and display in
/proc/fs/fscache/stats.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Wed, 20 Oct 2021 23:19:46 +0000 (00:19 +0100)]
cachefiles: Implement the I/O routines
Implement the I/O routines for cachefiles. There are two sets of routines
here: preparation and actual I/O.
Preparation for read involves looking to see whether there is data present,
and how much. Netfslib tells us what it wants us to do and we have the
option of adjusting shrinking and telling it whether to read from the
cache, download from the server or simply clear a region.
Preparation for write involves checking for space and defending against
possibly running short of space, if necessary punching out a hole in the
file so that we don't leave old data in the cache if we update the
coherency information.
Then there's a read routine and a write routine. They wait for the cookie
state to move to something appropriate and then start a potentially
asynchronous direct I/O operation upon it.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Thu, 21 Oct 2021 10:05:53 +0000 (11:05 +0100)]
cachefiles: Implement begin and end I/O operation
Implement the methods for beginning and ending an I/O operation.
When called to begin an I/O operation, we are guaranteed that the cookie
has reached a certain stage (we're called by fscache after it has done a
suitable wait).
If a file is available, we paste a ref over into the cache resources for
the I/O routines to use. This means that the object can be invalidated
whilst the I/O is ongoing without the need to synchronise as the file
pointer in the object is replaced, but the file pointer in the cache
resources is unaffected.
Ending the operation just requires ditching any refs we have and dropping
the access guarantee that fscache got for us on the cookie.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Thu, 21 Oct 2021 07:50:10 +0000 (08:50 +0100)]
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.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Thu, 21 Oct 2021 07:50:10 +0000 (08:50 +0100)]
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.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Thu, 18 Nov 2021 08:58:08 +0000 (08:58 +0000)]
cachefiles: Mark a backing file in use with an inode flag
Use an inode flag, S_KERNEL_FILE, to mark that a backing file is in use by
the kernel to prevent cachefiles or other kernel services from interfering
with that file.
Using S_SWAPFILE instead isn't really viable as that has other effects in
the I/O paths.
Signed-off-by: David Howells <dhowells@redhat.com>
David Howells [Wed, 17 Nov 2021 16:11:07 +0000 (16:11 +0000)]
cachefiles: Implement metadata/coherency data storage in xattrs
Use an xattr on each backing file in the cache to store some metadata, such
as the content type and the coherency data.
Five content types are defined:
(0) No content stored.
(1) The file contains a single monolithic blob and must be all or nothing.
This would be used for something like an AFS directory or a symlink.
(2) The file is populated with content completely up to a point with
nothing beyond that.
(3) The file has a map attached and is sparsely populated. This would be
stored in one or more additional xattrs.
(4) The file is dirty, being in the process of local modification and the
contents are not necessarily represented correctly by the metadata.
The file should be deleted if this is seen on binding.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Wed, 17 Nov 2021 15:48:06 +0000 (15:48 +0000)]
cachefiles: Implement key to filename encoding
Implement a function to encode a binary cookie key as something that can be
used as a filename. Four options are considered:
(1) All printable chars with no '/' characters. Prepend a 'D' to indicate
the encoding but otherwise use as-is.
(2) Appears to be an array of __be32. Encode as 'S' plus a list of
hex-encoded 32-bit ints separated by commas. If a number is 0, it is
rendered as "" instead of "0".
(3) Appears to be an array of __le32. Encoded as (2) but with a 'T'
encoding prefix.
(4) Encoded as base64 with an 'E' prefix plus a second char indicating how
much padding is involved. A non-standard base64 encoding is used
because '/' cannot be used in the encoded form.
If (1) is not possible, whichever of (2), (3) or (4) produces the shortest
string is selected (hex-encoding a number may be less dense than base64
encoding it).
Note that the prefix characters have to be selected from the set [DEIJST@]
lest cachefilesd remove the files because it recognise the name.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Thu, 21 Oct 2021 08:55:21 +0000 (09:55 +0100)]
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>
cc: linux-cachefs@redhat.com
David Howells [Thu, 21 Oct 2021 07:34:55 +0000 (08:34 +0100)]
cachefiles: Implement a function to get/create a directory in the cache
Implement a function to get/create structural directories in the cache.
This is used for setting up a cache and creating volume substructures. The
directory in memory are marked with the S_KERNEL_FILE inode flag whilst
they're in use to tell rmdir to reject attempts to remove them.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Thu, 18 Nov 2021 08:58:08 +0000 (08:58 +0000)]
vfs, cachefiles: Mark a backing file in use with an inode flag
Use an inode flag, S_KERNEL_FILE, to mark that a backing file is in use by
the kernel to prevent cachefiles or other kernel services from interfering
with that file.
Alter rmdir to reject attempts to remove a directory marked with this flag.
This is used by cachefiles to prevent cachefilesd from removing them.
Using S_SWAPFILE instead isn't really viable as that has other effects in
the I/O paths.
Signed-off-by: David Howells <dhowells@redhat.com>
David Howells [Thu, 21 Oct 2021 07:59:46 +0000 (08:59 +0100)]
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>
cc: linux-cachefs@redhat.com
David Howells [Fri, 26 Nov 2021 15:12:07 +0000 (15:12 +0000)]
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>
David Howells [Thu, 21 Oct 2021 07:15:26 +0000 (08:15 +0100)]
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>
cc: linux-cachefs@redhat.com
David Howells [Fri, 26 Nov 2021 14:45:38 +0000 (14:45 +0000)]
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>
David Howells [Mon, 10 Feb 2020 10:00:21 +0000 (10:00 +0000)]
vfs: Provide S_KERNEL_FILE inode flag
Provide an S_KERNEL_FILE inode flag that a kernel service, e.g. cachefiles,
can set to ward off other kernel services and drivers (including itself)
from using files it is actively using.
Signed-off-by: David Howells <dhowells@redhat.com>
David Howells [Wed, 20 Oct 2021 13:06:34 +0000 (14:06 +0100)]
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:
David Howells [Wed, 20 Oct 2021 13:06:34 +0000 (14:06 +0100)]
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>
cc: linux-cachefs@redhat.com
David Howells [Wed, 20 Oct 2021 22:50:01 +0000 (23:50 +0100)]
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>cc: linux-cachefs@redhat.com
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:
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:
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>
cc: linux-cachefs@redhat.com
David Howells [Wed, 20 Oct 2021 13:06:34 +0000 (14:06 +0100)]
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:
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:
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>
cc: linux-cachefs@redhat.com
David Howells [Thu, 11 Nov 2021 23:14:29 +0000 (23:14 +0000)]
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:
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.
David Howells [Wed, 20 Oct 2021 13:06:34 +0000 (14:06 +0100)]
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:
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>
cc: linux-cachefs@redhat.com
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.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Wed, 20 Oct 2021 14:53:34 +0000 (15:53 +0100)]
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:
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:
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.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Wed, 20 Oct 2021 14:53:34 +0000 (15:53 +0100)]
fscache: Implement simple cookie state machine
Implement a very simple cookie state machine to handle lookup, withdrawal,
relinquishment and, eventually, timed committing and invalidation.
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.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Wed, 20 Oct 2021 14:26:17 +0000 (15:26 +0100)]
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>
cc: linux-cachefs@redhat.com
David Howells [Wed, 20 Oct 2021 14:53:34 +0000 (15:53 +0100)]
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:
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.
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.
David Howells [Wed, 20 Oct 2021 14:26:17 +0000 (15:26 +0100)]
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:
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>
cc: linux-cachefs@redhat.com
David Howells [Wed, 20 Oct 2021 14:53:34 +0000 (15:53 +0100)]
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.
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:
David Howells [Wed, 20 Oct 2021 14:26:17 +0000 (15:26 +0100)]
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.
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 is a 64-bit integer 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:
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.
David Howells [Wed, 20 Oct 2021 14:45:28 +0000 (15:45 +0100)]
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.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
David Howells [Wed, 20 Oct 2021 13:30:37 +0000 (14:30 +0100)]
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>
cc: linux-cachefs@redhat.com
David Howells [Mon, 25 Oct 2021 20:53:44 +0000 (21:53 +0100)]
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>
Jeff Layton [Tue, 23 Nov 2021 12:30:38 +0000 (07:30 -0500)]
ceph: initialize i_size variable in ceph_sync_read
Newer compilers seem to determine that this variable being uninitialized
isn't a problem, but older compilers (from the RHEL8 era) seem to choke
on it and complain that it could be used uninitialized.
Go ahead and initialize the variable at declaration time to silence
potential compiler warnings.
Fixes: c3d8e0b5de48 ("ceph: return the real size read when it hits EOF") Reviewed-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jeff Layton <jlayton@kernel.org>
Hu Weiwen [Mon, 22 Nov 2021 14:22:12 +0000 (22:22 +0800)]
ceph: fix duplicate increment of opened_inodes metric
opened_inodes is incremented twice when the same inode is opened twice
with O_RDONLY and O_WRONLY respectively.
To reproduce, run this python script, then check the metrics:
import os
for _ in range(10000):
fd_r = os.open('a', os.O_RDONLY)
fd_w = os.open('a', os.O_WRONLY)
os.close(fd_r)
os.close(fd_w)
Fixes: 1dd8d4708136 ("ceph: metrics for opened files, pinned caps and opened inodes") Reviewed-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Hu Weiwen <sehuww@mail.scut.edu.cn> Signed-off-by: Jeff Layton <jlayton@kernel.org>
Linus Torvalds [Sun, 21 Nov 2021 19:25:19 +0000 (11:25 -0800)]
Merge tag 'x86-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
- Move the command line preparation and the early command line parsing
earlier so that the command line parameters which affect
early_reserve_memory(), e.g. efi=nosftreserve, are taken into
account. This was broken when the invocation of
early_reserve_memory() was moved recently.
- Use an atomic type for the SGX page accounting, which is read and
written locklessly, to plug various race conditions related to it.
* tag 'x86-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sgx: Fix free page accounting
x86/boot: Pull up cmdline preparation and early param parsing
Linus Torvalds [Sun, 21 Nov 2021 19:17:50 +0000 (11:17 -0800)]
Merge tag 'perf-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 perf fixes from Thomas Gleixner:
- Remove unneded PEBS disabling when taking LBR snapshots to prevent an
unchecked MSR access error.
- Fix IIO event constraints for Snowridge and Skylake server chips.
* tag 'perf-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/perf: Fix snapshot_branch_stack warning in VM
perf/x86/intel/uncore: Fix IIO event constraints for Snowridge
perf/x86/intel/uncore: Fix IIO event constraints for Skylake Server
perf/x86/intel/uncore: Fix filter_tid mask for CHA events on Skylake Server
Linus Torvalds [Sun, 21 Nov 2021 18:26:35 +0000 (10:26 -0800)]
Merge tag 'powerpc-5.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull more powerpc fixes from Michael Ellerman:
- Fix a bug in copying of sigset_t for 32-bit systems, which caused X
to not start.
- Fix handling of shared LSIs (rare) with the xive interrupt controller
(Power9/10).
- Fix missing TOC setup in some KVM code, which could result in oopses
depending on kernel data layout.
- Fix DMA mapping when we have persistent memory and only one DMA
window available.
- Fix further problems with STRICT_KERNEL_RWX on 8xx, exposed by a
recent fix.
- A couple of other minor fixes.
Thanks to Alexey Kardashevskiy, Aneesh Kumar K.V, Cédric Le Goater,
Christian Zigotzky, Christophe Leroy, Daniel Axtens, Finn Thain, Greg
Kurz, Masahiro Yamada, Nicholas Piggin, and Uwe Kleine-König.
* tag 'powerpc-5.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/xive: Change IRQ domain to a tree domain
powerpc/8xx: Fix pinned TLBs with CONFIG_STRICT_KERNEL_RWX
powerpc/signal32: Fix sigset_t copy
powerpc/book3e: Fix TLBCAM preset at boot
powerpc/pseries/ddw: Do not try direct mapping with persistent memory and one window
powerpc/pseries/ddw: simplify enable_ddw()
powerpc/pseries/ddw: Revert "Extend upper limit for huge DMA window for persistent memory"
powerpc/pseries: Fix numa FORM2 parsing fallback code
powerpc/pseries: rename numa_dist_table to form2_distances
powerpc: clean vdso32 and vdso64 directories
powerpc/83xx/mpc8349emitx: Drop unused variable
KVM: PPC: Book3S HV: Use GLOBAL_TOC for kvmppc_h_set_dabr/xdabr()
Linus Torvalds [Sat, 20 Nov 2021 21:17:24 +0000 (13:17 -0800)]
Merge branch 'akpm' (patches from Andrew)
Merge misc fixes from Andrew Morton:
"15 patches.
Subsystems affected by this patch series: ipc, hexagon, mm (swap,
slab-generic, kmemleak, hugetlb, kasan, damon, and highmem), and proc"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
proc/vmcore: fix clearing user buffer by properly using clear_user()
kmap_local: don't assume kmap PTEs are linear arrays in memory
mm/damon/dbgfs: fix missed use of damon_dbgfs_lock
mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation
kasan: test: silence intentional read overflow warnings
hugetlb, userfaultfd: fix reservation restore on userfaultfd error
hugetlb: fix hugetlb cgroup refcounting during mremap
mm: kmemleak: slob: respect SLAB_NOLEAKTRACE flag
hexagon: ignore vmlinux.lds
hexagon: clean up timer-regs.h
hexagon: export raw I/O routines for modules
mm: emit the "free" trace report before freeing memory in kmem_cache_free()
shm: extend forced shm destroy to support objects from several IPC nses
ipc: WARN if trying to remove ipc object which is absent
mm/swap.c:put_pages_list(): reinitialise the page list
Linus Torvalds [Sat, 20 Nov 2021 19:05:10 +0000 (11:05 -0800)]
Merge tag 'block-5.16-2021-11-19' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
- Flip a cap check to avoid a selinux error (Alistair)
- Fix for a regression this merge window where we can miss a queue ref
put (me)
- Un-mark pstore-blk as broken, as the condition that triggered that
change has been rectified (Kees)
- Queue quiesce and sync fixes (Ming)
- FUA insertion fix (Ming)
- blk-cgroup error path put fix (Yu)
* tag 'block-5.16-2021-11-19' of git://git.kernel.dk/linux-block:
blk-mq: don't insert FUA request with data into scheduler queue
blk-cgroup: fix missing put device in error path from blkg_conf_pref()
block: avoid to quiesce queue in elevator_init_mq
Revert "mark pstore-blk as broken"
blk-mq: cancel blk-mq dispatch work in both blk_cleanup_queue and disk_release()
block: fix missing queue put in error path
block: Check ADMIN before NICE for IOPRIO_CLASS_RT
Linus Torvalds [Sat, 20 Nov 2021 18:59:03 +0000 (10:59 -0800)]
Merge tag 'pinctrl-v5.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl
Pull pin control fixes from Linus Walleij:
"There is an ACPI stubs fix which is ACKed by the ACPI maintainer for
merging through my tree.
One item stand out and that is that I delete the <linux/sdb.h> header
that is used by nothing. I deleted this subsystem (through the GPIO
tree) a while back so I feel responsible for tidying up the floor.
Other than that it is the usual mistakes, a bit noisy around build
issue and Kconfig then driver fixes.
Specifics:
- Fix some stubs causing compile issues for ACPI.
- Fix some wakeups on AMD IRQs shared between GPIO and SCI.
- Fix a build warning in the Tegra driver.
- Fix a Kconfig issue in the Qualcomm driver.
- Add a missing include the RALink driver.
- Return a valid type for the Apple pinctrl IRQs.
- Implement some Qualcomm SDM845 dual-edge errata.
- Remove the unused <linux/sdb.h> header. (The subsystem was once
deleted by the pinctrl maintainer...)
- Fix a duplicate initialized in the Tegra driver.
- Fix register offsets for UFS and SDC in the Qualcomm SM8350 driver"
* tag 'pinctrl-v5.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
pinctrl: qcom: sm8350: Correct UFS and SDC offsets
pinctrl: tegra194: remove duplicate initializer again
Remove unused header <linux/sdb.h>
pinctrl: qcom: sdm845: Enable dual edge errata
pinctrl: apple: Always return valid type in apple_gpio_irq_type
pinctrl: ralink: include 'ralink_regs.h' in 'pinctrl-mt7620.c'
pinctrl: qcom: fix unmet dependencies on GPIOLIB for GPIOLIB_IRQCHIP
pinctrl: tegra: Return const pointer from tegra_pinctrl_get_group()
pinctrl: amd: Fix wakeups when IRQ is shared with SCI
ACPI: Add stubs for wakeup handler functions
Linus Torvalds [Sat, 20 Nov 2021 18:55:50 +0000 (10:55 -0800)]
Merge tag 's390-5.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Heiko Carstens:
- Add missing Kconfig option for ftrace direct multi sample, so it can
be compiled again, and also add s390 support for this sample.
- Update Christian Borntraeger's email address.
- Various fixes for memory layout setup. Besides other this makes it
possible to load shared DCSS segments again.
- Fix copy to user space of swapped kdump oldmem.
- Remove -mstack-guard and -mstack-size compile options when building
vdso binaries. This can happen when CONFIG_VMAP_STACK is disabled and
results in broken vdso code which causes more or less random
exceptions. Also remove the not needed -nostdlib option.
- Fix memory leak on cpu hotplug and return code handling in kexec
code.
- Wire up futex_waitv system call.
- Replace snprintf with sysfs_emit where appropriate.
* tag 's390-5.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
ftrace/samples: add s390 support for ftrace direct multi sample
ftrace/samples: add missing Kconfig option for ftrace direct multi sample
MAINTAINERS: update email address of Christian Borntraeger
s390/kexec: fix memory leak of ipl report buffer
s390/kexec: fix return code handling
s390/dump: fix copying to user-space of swapped kdump oldmem
s390: wire up sys_futex_waitv system call
s390/vdso: filter out -mstack-guard and -mstack-size
s390/vdso: remove -nostdlib compiler flag
s390: replace snprintf in show functions with sysfs_emit
s390/boot: simplify and fix kernel memory layout setup
s390/setup: re-arrange memblock setup
s390/setup: avoid using memblock_enforce_memory_limit
s390/setup: avoid reserving memory above identity mapping
Linus Torvalds [Sat, 20 Nov 2021 18:47:16 +0000 (10:47 -0800)]
Merge tag '5.16-rc1-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6
Pull cifs fixes from Steve French:
"Three small cifs/smb3 fixes: two to address minor coverity issues and
one cleanup"
* tag '5.16-rc1-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: introduce cifs_ses_mark_for_reconnect() helper
cifs: protect srv_count with cifs_tcp_ses_lock
cifs: move debug print out of spinlock
proc/vmcore: fix clearing user buffer by properly using clear_user()
To clear a user buffer we cannot simply use memset, we have to use
clear_user(). With a virtio-mem device that registers a vmcore_cb and
has some logically unplugged memory inside an added Linux memory block,
I can easily trigger a BUG by copying the vmcore via "cp":
Some x86-64 CPUs have a CPU feature called "Supervisor Mode Access
Prevention (SMAP)", which is used to detect wrong access from the kernel
to user buffers like this: SMAP triggers a permissions violation on
wrong access. In the x86-64 variant of clear_user(), SMAP is properly
handled via clac()+stac().
To fix, properly use clear_user() when we're dealing with a user buffer.
Link: https://lkml.kernel.org/r/20211112092750.6921-1-david@redhat.com Fixes: 997c136f518c ("fs/proc/vmcore.c: add hook to read_from_oldmem() to check for non-ram pages") Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Philipp Rudo <prudo@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ard Biesheuvel [Sat, 20 Nov 2021 00:43:55 +0000 (16:43 -0800)]
kmap_local: don't assume kmap PTEs are linear arrays in memory
The kmap_local conversion broke the ARM architecture, because the new
code assumes that all PTEs used for creating kmaps form a linear array
in memory, and uses array indexing to look up the kmap PTE belonging to
a certain kmap index.
On ARM, this cannot work, not only because the PTE pages may be
non-adjacent in memory, but also because ARM/!LPAE interleaves hardware
entries and extended entries (carrying software-only bits) in a way that
is not compatible with array indexing.
Fortunately, this only seems to affect configurations with more than 8
CPUs, due to the way the per-CPU kmap slots are organized in memory.
Work around this by permitting an architecture to set a Kconfig symbol
that signifies that the kmap PTEs do not form a lineary array in memory,
and so the only way to locate the appropriate one is to walk the page
tables.
Link: https://lore.kernel.org/linux-arm-kernel/20211026131249.3731275-1-ardb@kernel.org/ Link: https://lkml.kernel.org/r/20211116094737.7391-1-ardb@kernel.org Fixes: 2a15ba82fa6c ("ARM: highmem: Switch to generic kmap atomic") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reported-by: Quanyang Wang <quanyang.wang@windriver.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SeongJae Park [Sat, 20 Nov 2021 00:43:52 +0000 (16:43 -0800)]
mm/damon/dbgfs: fix missed use of damon_dbgfs_lock
DAMON debugfs is supposed to protect dbgfs_ctxs, dbgfs_nr_ctxs, and
dbgfs_dirs using damon_dbgfs_lock. However, some of the code is
accessing the variables without the protection. This fixes it by
protecting all such accesses.
Link: https://lkml.kernel.org/r/20211110145758.16558-3-sj@kernel.org Fixes: 75c1c2b53c78 ("mm/damon/dbgfs: support multiple contexts") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SeongJae Park [Sat, 20 Nov 2021 00:43:49 +0000 (16:43 -0800)]
mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation
Patch series "DAMON fixes".
This patch (of 2):
DAMON users can trigger below warning in '__alloc_pages()' by invoking
write() to some DAMON debugfs files with arbitrarily high count
argument, because DAMON debugfs interface allocates some buffers based
on the user-specified 'count'.
As done in commit d73dad4eb5ad ("kasan: test: bypass __alloc_size
checks") for __write_overflow warnings, also silence some more cases
that trip the __read_overflow warnings seen in 5.16-rc1[1]:
In file included from include/linux/string.h:253,
from include/linux/bitmap.h:10,
from include/linux/cpumask.h:12,
from include/linux/mm_types_task.h:14,
from include/linux/mm_types.h:5,
from include/linux/page-flags.h:13,
from arch/arm64/include/asm/mte.h:14,
from arch/arm64/include/asm/pgtable.h:12,
from include/linux/pgtable.h:6,
from include/linux/kasan.h:29,
from lib/test_kasan.c:10:
In function 'memcmp',
inlined from 'kasan_memcmp' at lib/test_kasan.c:897:2:
include/linux/fortify-string.h:263:25: error: call to '__read_overflow' declared with attribute error: detected read beyond size of object (1st parameter)
263 | __read_overflow();
| ^~~~~~~~~~~~~~~~~
In function 'memchr',
inlined from 'kasan_memchr' at lib/test_kasan.c:872:2:
include/linux/fortify-string.h:277:17: error: call to '__read_overflow' declared with attribute error: detected read beyond size of object (1st parameter)
277 | __read_overflow();
| ^~~~~~~~~~~~~~~~~
Mina Almasry [Sat, 20 Nov 2021 00:43:43 +0000 (16:43 -0800)]
hugetlb, userfaultfd: fix reservation restore on userfaultfd error
Currently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we
bail out using "goto out_release_unlock;" in the cases where idx >=
size, or !huge_pte_none(), the code will detect that new_pagecache_page
== false, and so call restore_reserve_on_error(). In this case I see
restore_reserve_on_error() delete the reservation, and the following
call to remove_inode_hugepages() will increment h->resv_hugepages
causing a 100% reproducible leak.
We should treat the is_continue case similar to adding a page into the
pagecache and set new_pagecache_page to true, to indicate that there is
no reservation to restore on the error path, and we need not call
restore_reserve_on_error(). Rename new_pagecache_page to
page_in_pagecache to make that clear.
Link: https://lkml.kernel.org/r/20211117193825.378528-1-almasrymina@google.com Fixes: c7b1850dfb41 ("hugetlb: don't pass page cache pages to restore_reserve_on_error") Signed-off-by: Mina Almasry <almasrymina@google.com> Reported-by: James Houghton <jthoughton@google.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Wei Xu <weixugc@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hugetlb: fix hugetlb cgroup refcounting during mremap
When hugetlb_vm_op_open() is called during copy_vma(), we may take the
reference to resv_map->css. Later, when clearing the reservation
pointer of old_vma after transferring it to new_vma, we forget to drop
the reference to resv_map->css. This leads to a reference leak of css.
Fixes this by adding a check to drop reservation css reference in
clear_vma_resv_huge_pages()
Link: https://lkml.kernel.org/r/20211113154412.91134-1-minhquangbui99@gmail.com Fixes: 550a7d60bd5e35 ("mm, hugepages: add mremap() support for hugepage backed vma") Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rustam Kovhaev [Sat, 20 Nov 2021 00:43:37 +0000 (16:43 -0800)]
mm: kmemleak: slob: respect SLAB_NOLEAKTRACE flag
When kmemleak is enabled for SLOB, system does not boot and does not
print anything to the console. At the very early stage in the boot
process we hit infinite recursion from kmemleak_init() and eventually
kernel crashes.
kmemleak_init() specifies SLAB_NOLEAKTRACE for KMEM_CACHE(), but
kmem_cache_create_usercopy() removes it because CACHE_CREATE_MASK is not
valid for SLOB.
Let's fix CACHE_CREATE_MASK and make kmemleak work with SLOB
Link: https://lkml.kernel.org/r/20211115020850.3154366-1-rkovhaev@gmail.com Fixes: d8843922fba4 ("slab: Ignore internal flags in cache creation") Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Glauber Costa <glommer@parallels.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The values in this header are only used in one file each, if they are
used at all. Remove the header and sink all of the constants into their
respective files.
TCX0_CLK_RATE is only used in arch/hexagon/include/asm/timex.h
TIMER_ENABLE, RTOS_TIMER_INT, RTOS_TIMER_REGS_ADDR are only used in
arch/hexagon/kernel/time.c.
SLEEP_CLK_RATE and TIMER_CLR_ON_MATCH have both been unused since the
file's introduction in commit 71e4a47f32f4 ("Hexagon: Add time and timer
functions").
TIMER_ENABLE is redefined as BIT(0) so the shift is moved into the
definition, rather than its use.
Link: https://lkml.kernel.org/r/20211115174250.1994179-3-nathan@kernel.org Signed-off-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Brian Cain <bcain@codeaurora.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Yunfeng Ye [Sat, 20 Nov 2021 00:43:25 +0000 (16:43 -0800)]
mm: emit the "free" trace report before freeing memory in kmem_cache_free()
After the memory is freed, it can be immediately allocated by other
CPUs, before the "free" trace report has been emitted. This causes
inaccurate traces.
For example, if the following sequence of events occurs:
shm: extend forced shm destroy to support objects from several IPC nses
Currently, the exit_shm() function not designed to work properly when
task->sysvshm.shm_clist holds shm objects from different IPC namespaces.
This is a real pain when sysctl kernel.shm_rmid_forced = 1, because it
leads to use-after-free (reproducer exists).
This is an attempt to fix the problem by extending exit_shm mechanism to
handle shm's destroy from several IPC ns'es.
To achieve that we do several things:
1. add a namespace (non-refcounted) pointer to the struct shmid_kernel
2. during new shm object creation (newseg()/shmget syscall) we
initialize this pointer by current task IPC ns
3. exit_shm() fully reworked such that it traverses over all shp's in
task->sysvshm.shm_clist and gets IPC namespace not from current task
as it was before but from shp's object itself, then call
shm_destroy(shp, ns).
Note: We need to be really careful here, because as it was said before
(1), our pointer to IPC ns non-refcnt'ed. To be on the safe side we
using special helper get_ipc_ns_not_zero() which allows to get IPC ns
refcounter only if IPC ns not in the "state of destruction".
Q/A
Q: Why can we access shp->ns memory using non-refcounted pointer?
A: Because shp object lifetime is always shorther than IPC namespace
lifetime, so, if we get shp object from the task->sysvshm.shm_clist
while holding task_lock(task) nobody can steal our namespace.
Q: Does this patch change semantics of unshare/setns/clone syscalls?
A: No. It's just fixes non-covered case when process may leave IPC
namespace without getting task->sysvshm.shm_clist list cleaned up.
Link: https://lkml.kernel.org/r/67bb03e5-f79c-1815-e2bf-949c67047418@colorfullife.com Link: https://lkml.kernel.org/r/20211109151501.4921-1-manfred@colorfullife.com Fixes: ab602f79915 ("shm: make exit_shm work proportional to task activity") Co-developed-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Andrei Vagin <avagin@gmail.com> Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Cc: Vasily Averin <vvs@virtuozzo.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc: WARN if trying to remove ipc object which is absent
Patch series "shm: shm_rmid_forced feature fixes".
Some time ago I met kernel crash after CRIU restore procedure,
fortunately, it was CRIU restore, so, I had dump files and could do
restore many times and crash reproduced easily. After some
investigation I've constructed the minimal reproducer. It was found
that it's use-after-free and it happens only if sysctl
kernel.shm_rmid_forced = 1.
The key of the problem is that the exit_shm() function not handles shp's
object destroy when task->sysvshm.shm_clist contains items from
different IPC namespaces. In most cases this list will contain only
items from one IPC namespace.
How can this list contain object from different namespaces? The
exit_shm() function is designed to clean up this list always when
process leaves IPC namespace. But we made a mistake a long time ago and
did not add a exit_shm() call into the setns() syscall procedures.
The first idea was just to add this call to setns() syscall but it
obviously changes semantics of setns() syscall and that's
userspace-visible change. So, I gave up on this idea.
The first real attempt to address the issue was just to omit forced
destroy if we meet shp object not from current task IPC namespace [1].
But that was not the best idea because task->sysvshm.shm_clist was
protected by rwsem which belongs to current task IPC namespace. It
means that list corruption may occur.
Second approach is just extend exit_shm() to properly handle shp's from
different IPC namespaces [2]. This is really non-trivial thing, I've
put a lot of effort into that but not believed that it's possible to
make it fully safe, clean and clear.
Thanks to the efforts of Manfred Spraul working an elegant solution was
designed. Thanks a lot, Manfred!
Eric also suggested the way to address the issue in ("[RFC][PATCH] shm:
In shm_exit destroy all created and never attached segments") Eric's
idea was to maintain a list of shm_clists one per IPC namespace, use
lock-less lists. But there is some extra memory consumption-related
concerns.
An alternative solution which was suggested by me was implemented in
("shm: reset shm_clist on setns but omit forced shm destroy"). The idea
is pretty simple, we add exit_shm() syscall to setns() but DO NOT
destroy shm segments even if sysctl kernel.shm_rmid_forced = 1, we just
clean up the task->sysvshm.shm_clist list.
This chages semantics of setns() syscall a little bit but in comparision
to the "naive" solution when we just add exit_shm() without any special
exclusions this looks like a safer option.
Matthew Wilcox [Sat, 20 Nov 2021 00:43:15 +0000 (16:43 -0800)]
mm/swap.c:put_pages_list(): reinitialise the page list
While free_unref_page_list() puts pages onto the CPU local LRU list, it
does not remove them from the list they were passed in on. That makes
the list_head appear to be non-empty, and would lead to various
corruption problems if we didn't have an assertion that the list was
empty.
Reinitialise the list after calling free_unref_page_list() to avoid this
problem.
Link: https://lkml.kernel.org/r/YYp40A2lNrxaZji8@casper.infradead.org Fixes: 988c69f1bc23 ("mm: optimise put_pages_list()") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Steve French <stfrench@microsoft.com> Reported-by: Namjae Jeon <linkinjeon@kernel.org> Tested-by: Steve French <stfrench@microsoft.com> Tested-by: Namjae Jeon <linkinjeon@kernel.org> Cc: Steve French <smfrench@gmail.com> Cc: Hyeoncheol Lee <hyc.lee@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Fri, 19 Nov 2021 22:15:14 +0000 (14:15 -0800)]
Merge tag 'libata-5.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/libata
Pull libata fixes from Damien Le Moal:
- Prevent accesses to unsupported log pages as that causes device scan
failures with LLDDs using libsas (from me).
- A couple of fixes for AMD AHCI adapters handling of low power modes
and resume (from Mario).
- Fix a compilation warning (from me).
* tag 'libata-5.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/libata:
ata: libata-sata: Declare ata_ncq_sdev_attrs static
ata: libahci: Adjust behavior when StorageD3Enable _DSD is set
ata: ahci: Add Green Sardine vendor ID as board_ahci_mobile
ata: libata: add missing ata_identify_page_supported() calls
ata: libata: improve ata_read_log_page() error message
Linus Torvalds [Fri, 19 Nov 2021 21:50:48 +0000 (13:50 -0800)]
Merge tag 'trace-v5.16-6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix double free in destroy_hist_field
- Harden memset() of trace_iterator structure
- Do not warn in trace printk check when test buffer fills up
* tag 'trace-v5.16-6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Don't use out-of-sync va_list in event printing
tracing: Use memset_startat() to zero struct trace_iterator
tracing/histogram: Fix UAF in destroy_hist_field()
projects / ceph-client.git / log