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Pull nfsd updates from Chuck Lever:
"Jeff Layton contributed an implementation of NFSv4.2+ attribute
delegation, as described here:
https://www.ietf.org/archive/id/draft-ietf-nfsv4-delstid-08.html
This interoperates with similar functionality introduced into the
Linux NFS client in v6.11. An attribute delegation permits an NFS
client to manage a file's mtime, rather than flushing dirty data to
the NFS server so that the file's mtime reflects the last write, which
is considerably slower.
Neil Brown contributed dynamic NFSv4.1 session slot table resizing.
This facility enables NFSD to increase or decrease the number of slots
per NFS session depending on server memory availability. More session
slots means greater parallelism.
Chuck Lever fixed a long-standing latent bug where NFSv4 COMPOUND
encoding screws up when crossing a page boundary in the encoding
buffer. This is a zero-day bug, but hitting it is rare and depends on
the NFS client implementation. The Linux NFS client does not happen to
trigger this issue.
A variety of bug fixes and other incremental improvements fill out the
list of commits in this release. Great thanks to all contributors,
reviewers, testers, and bug reporters who participated during this
development cycle"
* tag 'nfsd-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (42 commits)
sunrpc: Remove gss_{de,en}crypt_xdr_buf deadcode
sunrpc: Remove gss_generic_token deadcode
sunrpc: Remove unused xprt_iter_get_xprt
Revert "SUNRPC: Reduce thread wake-up rate when receiving large RPC messages"
nfsd: implement OPEN_ARGS_SHARE_ACCESS_WANT_OPEN_XOR_DELEGATION
nfsd: handle delegated timestamps in SETATTR
nfsd: add support for delegated timestamps
nfsd: rework NFS4_SHARE_WANT_* flag handling
nfsd: add support for FATTR4_OPEN_ARGUMENTS
nfsd: prepare delegation code for handing out *_ATTRS_DELEG delegations
nfsd: rename NFS4_SHARE_WANT_* constants to OPEN4_SHARE_ACCESS_WANT_*
nfsd: switch to autogenerated definitions for open_delegation_type4
nfs_common: make include/linux/nfs4.h include generated nfs4_1.h
nfsd: fix handling of delegated change attr in CB_GETATTR
SUNRPC: Document validity guarantees of the pointer returned by reserve_space
NFSD: Insulate nfsd4_encode_fattr4() from page boundaries in the encode buffer
NFSD: Insulate nfsd4_encode_secinfo() from page boundaries in the encode buffer
NFSD: Refactor nfsd4_do_encode_secinfo() again
NFSD: Insulate nfsd4_encode_readlink() from page boundaries in the encode buffer
NFSD: Insulate nfsd4_encode_read_plus_data() from page boundaries in the encode buffer
...
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Quite a few places want to build a struct qstr by given string;
it would be convenient to have a primitive doing that, rather
than open-coding it via QSTR_INIT().
The closest approximation was in bcachefs, but that expands to
initializer list - {.len = strlen(string), .name = string}.
It would be more useful to have it as compound literal -
(struct qstr){.len = strlen(string), .name = string}.
Unlike initializer list it's a valid expression. What's more,
it's a valid lvalue - it's an equivalent of anonymous local
variable with such initializer, so the things like
path->dentry = d_alloc_pseudo(mnt->mnt_sb, &QSTR(name));
are valid. It can also be used as initializer, with identical
effect -
struct qstr x = (struct qstr){.name = s, .len = strlen(s)};
is equivalent to
struct qstr anon_variable = {.name = s, .len = strlen(s)};
struct qstr x = anon_variable;
// anon_variable is never used after that point
and any even remotely sane compiler will manage to collapse that
into
struct qstr x = {.name = s, .len = strlen(s)};
What compound literals can't be used for is initialization of
global variables, but those are covered by QSTR_INIT().
This commit lifts definition(s) of QSTR() into linux/dcache.h,
converts it to compound literal (all bcachefs users are fine
with that) and converts assorted open-coded instances to using
that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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9p wants to be able to build a path from given dentry to fs root and keep
it valid over a blocking operation.
->s_vfs_rename_mutex would be a natural candidate, but there are places
where we need that and where we have no way to tell if ->s_vfs_rename_mutex
is already held deeper in callchain. Moreover, it's only held for
cross-directory renames; name changes within the same directory happen
without it.
Solution:
* have d_move() done in ->rename() rather than in its caller
* maintain a 9p-private rwsem (per-filesystem)
* hold it exclusive over the relevant part of ->rename()
* hold it shared over the places where we want the path.
That almost works. FS_RENAME_DOES_D_MOVE is enough to put all d_move()
and d_exchange() calls under filesystem's control. However, there's
also __d_unalias(), which isn't covered by any of that.
If ->lookup() hits a directory inode with preexisting dentry elsewhere
(due to e.g. rename done on server behind our back), d_splice_alias()
called by ->lookup() will move/rename that alias.
Add a couple of optional methods, so that __d_unalias() would do
if alias->d_op->d_unalias_trylock != NULL
if (!alias->d_op->d_unalias_trylock(alias))
fail (resulting in -ESTALE from lookup)
__d_move(...)
if alias->d_op->d_unalias_unlock != NULL
alias->d_unalias_unlock(alias)
where it currently does __d_move(). 9p instances do down_write_trylock()
and up_write() of ->rename_mutex.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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->d_name use is a UAF if the userland side of things can be slowed down
by attacker.
Tested-by: Mike Marshall <hubcap@omnibond.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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theoretically, ->d_name use in there is a UAF, but only if you are messing with
tracepoints...
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Pass the stable name all the way down to ->rpc_ops->lookup() instances.
Note that passing &dentry->d_name is safe in e.g. nfs_lookup() - it *is*
stable there, as it is in ->create() et.al.
dget_parent() in nfs_instantiate() should be redundant - it'd better be
stable there; if it's not, we have more trouble, since ->d_name would
also be unsafe in such case.
nfs_submount() and nfs4_submount() may or may not require fixes - if
they ever get moved on server with fhandle preserved, we are in trouble
there...
UAF window is fairly narrow here and exfiltration requires the ability
to watch the traffic.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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we can't kill __nfs_lookup_revalidate() completely, but ->d_parent boilerplate
in it is gone
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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No need to mess with dget_parent() for the former; for the latter we really should
not rely upon ->d_name.name remaining stable. Theoretically a UAF, but it's
hard to exfiltrate the information...
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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No need to mess with dget_parent() for the former; for the latter we really should
not rely upon ->d_name.name remaining stable - it's a real-life UAF.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... no need to bother with ->d_lock and ->d_parent->d_inode.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The only thing it's using is parent directory inode and we are already
given a stable reference to that - no need to bother with boilerplate.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Currently get_fscrypt_altname() requires ->r_dentry->d_name to be stable
and it gets that in almost all cases. The only exception is ->d_revalidate(),
where we have a stable name, but it's passed separately - dentry->d_name
is not stable there.
Propagate it down to get_fscrypt_altname() as a new field of struct
ceph_mds_request - ->r_dname, to be used instead ->r_dentry->d_name
when non-NULL.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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No need to mess with the boilerplate for obtaining what we already
have. Note that ceph is one of the "will want a path from filesystem
root if we want to talk to server" cases, so the name of the last
component is of little use - it is passed to fscrypt_d_revalidate()
and it's used to deal with (also crypt-related) case in request
marshalling, when encrypted name turns out to be too long. The former
is not a problem, but the latter is racy; that part will be handled
in the next commit.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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No need to bother with boilerplate for obtaining the latter and for
the former we really should not count upon ->d_name.name remaining
stable under us.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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->d_revalidate() often needs to access dentry parent and name; that has
to be done carefully, since the locking environment varies from caller
to caller. We are not guaranteed that dentry in question will not be
moved right under us - not unless the filesystem is such that nothing
on it ever gets renamed.
It can be dealt with, but that results in boilerplate code that isn't
even needed - the callers normally have just found the dentry via dcache
lookup and want to verify that it's in the right place; they already
have the values of ->d_parent and ->d_name stable. There is a couple
of exceptions (overlayfs and, to less extent, ecryptfs), but for the
majority of calls that song and dance is not needed at all.
It's easier to make ecryptfs and overlayfs find and pass those values if
there's a ->d_revalidate() instance to be called, rather than doing that
in the instances.
This commit only changes the calling conventions; making use of supplied
values is left to followups.
NOTE: some instances need more than just the parent - things like CIFS
may need to build an entire path from filesystem root, so they need
more precautions than the usual boilerplate. This series doesn't
do anything to that need - these filesystems have to keep their locking
mechanisms (rename_lock loops, use of dentry_path_raw(), private rwsem
a-la v9fs).
One thing to keep in mind when using name is that name->name will normally
point into the pathname being resolved; the filename in question occupies
name->len bytes starting at name->name, and there is NUL somewhere after it,
but it the next byte might very well be '/' rather than '\0'. Do not
ignore name->len.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... and check the "name might be unstable" predicate
the right way.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... rather than open-coding them. As a bonus, that avoids the pointless
work with extra allocations, etc. for long names.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... and document the constraints on the layout. Kept separate from
the previous commit to keep the noise separate from actual changes.
The reason for explicit __aligned() on ->name[] rather than relying
upon the alignment of the previous field is that the previous iteration
of that commit tried to save 4 bytes on 64bit by eliminating a hole
in there, which broke the assumptions in dentry_string_cmp().
Better spell it out and avoid the temptation for the future...
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Pull virtio updates from Michael Tsirkin:
"A small number of improvements all over the place:
- vdpa/octeon support for multiple interrupts
- virtio-pci support for error recovery
- vp_vdpa support for notification with data
- vhost/net fix to set num_buffers for spec compliance
- virtio-mem now works with kdump on s390
And small cleanups all over the place"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (23 commits)
virtio_blk: Add support for transport error recovery
virtio_pci: Add support for PCIe Function Level Reset
vhost/net: Set num_buffers for virtio 1.0
vdpa/octeon_ep: read vendor-specific PCI capability
virtio-pci: define type and header for PCI vendor data
vdpa/octeon_ep: handle device config change events
vdpa/octeon_ep: enable support for multiple interrupts per device
vdpa: solidrun: Replace deprecated PCI functions
s390/kdump: virtio-mem kdump support (CONFIG_PROC_VMCORE_DEVICE_RAM)
virtio-mem: support CONFIG_PROC_VMCORE_DEVICE_RAM
virtio-mem: remember usable region size
virtio-mem: mark device ready before registering callbacks in kdump mode
fs/proc/vmcore: introduce PROC_VMCORE_DEVICE_RAM to detect device RAM ranges in 2nd kernel
fs/proc/vmcore: factor out freeing a list of vmcore ranges
fs/proc/vmcore: factor out allocating a vmcore range and adding it to a list
fs/proc/vmcore: move vmcore definitions out of kcore.h
fs/proc/vmcore: prefix all pr_* with "vmcore:"
fs/proc/vmcore: disallow vmcore modifications while the vmcore is open
fs/proc/vmcore: replace vmcoredd_mutex by vmcore_mutex
fs/proc/vmcore: convert vmcore_cb_lock into vmcore_mutex
...
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The enable_uring module parameter allows administrators to enable/disable
io-uring support for FUSE at runtime. However, disabling io-uring while
connections already have it enabled can lead to an inconsistent state.
Fix this by keeping io-uring enabled on connections that were already using
it, even if the module parameter is later disabled. This ensures active
FUSE mounts continue to function correctly.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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All required parts are handled now, fuse-io-uring can
be enabled.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Avoid races and block request allocation until io-uring
queues are ready.
This is a especially important for background requests,
as bg request completion might cause lock order inversion
of the typical queue->lock and then fc->bg_lock
fuse_request_end
spin_lock(&fc->bg_lock);
flush_bg_queue
fuse_send_one
fuse_uring_queue_fuse_req
spin_lock(&queue->lock);
Signed-off-by: Bernd Schubert <bernd@bsbernd.com>
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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When the fuse-server terminates while the fuse-client or kernel
still has queued URING_CMDs, these commands retain references
to the struct file used by the fuse connection. This prevents
fuse_dev_release() from being invoked, resulting in a hung mount
point.
This patch addresses the issue by making queued URING_CMDs
cancelable, allowing fuse_dev_release() to proceed as expected
and preventing the mount point from hanging.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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This prepares queueing and sending background requests through
io-uring.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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This prepares queueing and sending foreground requests through
io-uring.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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These functions are also needed by fuse-over-io-uring.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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On teardown struct file_operations::uring_cmd requests
need to be completed by calling io_uring_cmd_done().
Not completing all ring entries would result in busy io-uring
tasks giving warning messages in intervals and unreleased
struct file.
Additionally the fuse connection and with that the ring can
only get released when all io-uring commands are completed.
Completion is done with ring entries that are
a) in waiting state for new fuse requests - io_uring_cmd_done
is needed
b) already in userspace - io_uring_cmd_done through teardown
is not needed, the request can just get released. If fuse server
is still active and commits such a ring entry, fuse_uring_cmd()
already checks if the connection is active and then complete the
io-uring itself with -ENOTCONN. I.e. special handling is not
needed.
This scheme is basically represented by the ring entry state
FRRS_WAIT and FRRS_USERSPACE.
Entries in state:
- FRRS_INIT: No action needed, do not contribute to
ring->queue_refs yet
- All other states: Are currently processed by other tasks,
async teardown is needed and it has to wait for the two
states above. It could be also solved without an async
teardown task, but would require additional if conditions
in hot code paths. Also in my personal opinion the code
looks cleaner with async teardown.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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This adds support for fuse request completion through ring SQEs
(FUSE_URING_CMD_COMMIT_AND_FETCH handling). After committing
the ring entry it becomes available for new fuse requests.
Handling of requests through the ring (SQE/CQE handling)
is complete now.
Fuse request data are copied through the mmaped ring buffer,
there is no support for any zero copy yet.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # io_uring
Reviewed-by: Luis Henriques <luis@igalia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Initially, ceph_fs_debugfs_init() had temporary
name buffer with hardcoded length of 80 symbols.
Then, it was hardcoded again for 100 symbols.
Finally, it makes sense to exchange hardcoded
value on properly defined constant and 255 symbols
should be enough for any name case.
Signed-off-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Reviewed-by: Patrick Donnelly <pdonnell@ibm.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
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The existence of the ceph_mds_request_head_old structure in the MDS
client code is no longer required due to improvements in handling
different MDS request header versions. This patch removes the now
redundant ceph_mds_request_head_old structure and replaces its usage
with the flexible and extensible ceph_mds_request_head structure.
Changes include:
- Modification of find_legacy_request_head to directly cast the
pointer to ceph_mds_request_head_legacy without going through the
old structure.
- Update sizeof calculations in create_request_message to use
offsetofend for consistency and future-proofing, rather than
referencing the old structure.
- Use of the structured ceph_mds_request_head directly instead of the
old one.
Additionally, this consolidation normalizes the handling of
request_head_version v1 to align with versions v2 and v3, leading to
a more consistent and maintainable codebase.
These changes simplify the codebase and reduce potential confusion
stemming from the existence of an obsolete structure.
Signed-off-by: Liang Jie <liangjie@lixiang.com>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
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Let's implement the get_device_ram() vmcore callback, so
architectures that select NEED_PROC_VMCORE_NEED_DEVICE_RAM, like s390
soon, can include that memory in a crash dump.
Merge ranges, and process ranges that might contain a mixture of plugged
and unplugged, to reduce the total number of ranges.
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20241204125444.1734652-12-david@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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in 2nd kernel
s390 allocates+prepares the elfcore hdr in the dump (2nd) kernel, not in
the crashed kernel.
RAM provided by memory devices such as virtio-mem can only be detected
using the device driver; when vmcore_init() is called, these device
drivers are usually not loaded yet, or the devices did not get probed
yet. Consequently, on s390 these RAM ranges will not be included in
the crash dump, which makes the dump partially corrupt and is
unfortunate.
Instead of deferring the vmcore_init() call, to an (unclear?) later point,
let's reuse the vmcore_cb infrastructure to obtain device RAM ranges as
the device drivers probe the device and get access to this information.
Then, we'll add these ranges to the vmcore, adding more PT_LOAD
entries and updating the offsets+vmcore size.
Use a separate Kconfig option to be set by an architecture to include this
code only if the arch really needs it. Further, we'll make the config
depend on the relevant drivers (i.e., virtio_mem) once they implement
support (next). The alternative of having a PROVIDE_PROC_VMCORE_DEVICE_RAM
config option was dropped for now for simplicity.
The current target use case is s390, which only creates an elf64
elfcore, so focusing on elf64 is sufficient.
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20241204125444.1734652-9-david@redhat.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Let's factor it out into include/linux/crash_dump.h, from where we can
use it also outside of vmcore.c later.
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20241204125444.1734652-8-david@redhat.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Let's factor it out into include/linux/crash_dump.h, from where we can
use it also outside of vmcore.c later.
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20241204125444.1734652-7-david@redhat.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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These vmcore defines are not related to /proc/kcore, move them out.
We'll move "struct vmcoredd_node" to vmcore.c, because it is only used
internally. While "struct vmcore" is only used internally for now,
we're planning on using it from inline functions in crash_dump.h next,
so move it to crash_dump.h.
While at it, rename "struct vmcore" to "struct vmcore_range", which is a
more suitable name and will make the usage of it outside of vmcore.c
clearer.
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20241204125444.1734652-6-david@redhat.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Let's use "vmcore: " as a prefix, converting the single "Kdump:
vmcore not initialized" one to effectively be "vmcore: not initialized".
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20241204125444.1734652-5-david@redhat.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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The vmcoredd_update_size() call and its effects (size/offset changes) are
currently completely unsynchronized, and will cause trouble when
performed concurrently, or when done while someone is already reading the
vmcore.
Let's protect all vmcore modifications by the vmcore_mutex, disallow vmcore
modifications while the vmcore is open, and warn on vmcore
modifications after the vmcore was already opened once: modifications
while the vmcore is open are unsafe, and modifications after the vmcore
was opened indicates trouble. Properly synchronize against concurrent
opening of the vmcore.
No need to grab the mutex during mmap()/read(): after we opened the
vmcore, modifications are impossible.
It's worth noting that modifications after the vmcore was opened are
completely unexpected, so failing if open, and warning if already opened
(+closed again) is good enough.
This change not only handles concurrent adding of device dumps +
concurrent reading of the vmcore properly, it also prepares for other
mechanisms that will modify the vmcore.
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20241204125444.1734652-4-david@redhat.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Now that we have a mutex that synchronizes against opening of the vmcore,
let's use that one to replace vmcoredd_mutex: there is no need to have
two separate ones.
This is a preparation for properly preventing vmcore modifications
after the vmcore was opened.
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20241204125444.1734652-3-david@redhat.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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We want to protect vmcore modifications from concurrent opening of
the vmcore, and also serialize vmcore modification.
(a) We can currently modify the vmcore after it was opened. This can happen
if a vmcoredd is added after the vmcore module was initialized and
already opened by user space. We want to fix that and prepare for
new code wanting to serialize against concurrent opening.
(b) To handle it cleanly we need to protect the modifications against
concurrent opening. As the modifications end up allocating memory and
can sleep, we cannot rely on the spinlock.
Let's convert the spinlock into a mutex to prepare for further changes.
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20241204125444.1734652-2-david@redhat.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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In xfs_inactive(), xfs_reflink_cancel_cow_range() is called
without error handling, risking unnoticed failures and
inconsistent behavior compared to other parts of the code.
Fix this issue by adding an error handling for the
xfs_reflink_cancel_cow_range(), improving code robustness.
Fixes: 6231848c3aa5 ("xfs: check for cow blocks before trying to clear them")
Cc: stable@vger.kernel.org # v4.17
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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xfs_dax_write_iomap_end
In xfs_dax_write_iomap_end(), directly return the result of
xfs_reflink_cancel_cow_range() when !written, ensuring proper
error propagation and improving code robustness.
Fixes: ea6c49b784f0 ("xfs: support CoW in fsdax mode")
Cc: stable@vger.kernel.org # v6.0
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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STATUS_NOT_A_REPARSE_POINT indicates that object does not have reparse point
buffer attached, for example returned by FSCTL_GET_REPARSE_POINT.
Currently STATUS_NOT_A_REPARSE_POINT is translated to -EIO. Change it to
-ENODATA which better describe the situation when no reparse point is set.
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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We're currently debugging issues with rebalance, where it's not making
progress as quickly as it should be (or sometimes not at all).
Add the full data_update to the move_extent_finish tracepoint, so we can
check that the replicas we wrote match what we were supposed to do.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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System performance is particularly sensitive to journal write latency,
the number of outstanding journal writes is bounded and we can't issue
journal flushes until other journal writes have completed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"The various patchsets are summarized below. Plus of course many
indivudual patches which are described in their changelogs.
- "Allocate and free frozen pages" from Matthew Wilcox reorganizes
the page allocator so we end up with the ability to allocate and
free zero-refcount pages. So that callers (ie, slab) can avoid a
refcount inc & dec
- "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to
use large folios other than PMD-sized ones
- "Fix mm/rodata_test" from Petr Tesarik performs some maintenance
and fixes for this small built-in kernel selftest
- "mas_anode_descend() related cleanup" from Wei Yang tidies up part
of the mapletree code
- "mm: fix format issues and param types" from Keren Sun implements a
few minor code cleanups
- "simplify split calculation" from Wei Yang provides a few fixes and
a test for the mapletree code
- "mm/vma: make more mmap logic userland testable" from Lorenzo
Stoakes continues the work of moving vma-related code into the
(relatively) new mm/vma.c
- "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David
Hildenbrand cleans up and rationalizes handling of gfp flags in the
page allocator
- "readahead: Reintroduce fix for improper RA window sizing" from Jan
Kara is a second attempt at fixing a readahead window sizing issue.
It should reduce the amount of unnecessary reading
- "synchronously scan and reclaim empty user PTE pages" from Qi Zheng
addresses an issue where "huge" amounts of pte pagetables are
accumulated:
https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/
Qi's series addresses this windup by synchronously freeing PTE
memory within the context of madvise(MADV_DONTNEED)
- "selftest/mm: Remove warnings found by adding compiler flags" from
Muhammad Usama Anjum fixes some build warnings in the selftests
code when optional compiler warnings are enabled
- "mm: don't use __GFP_HARDWALL when migrating remote pages" from
David Hildenbrand tightens the allocator's observance of
__GFP_HARDWALL
- "pkeys kselftests improvements" from Kevin Brodsky implements
various fixes and cleanups in the MM selftests code, mainly
pertaining to the pkeys tests
- "mm/damon: add sample modules" from SeongJae Park enhances DAMON to
estimate application working set size
- "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn
provides some cleanups to memcg's hugetlb charging logic
- "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song
removes the global swap cgroup lock. A speedup of 10% for a
tmpfs-based kernel build was demonstrated
- "zram: split page type read/write handling" from Sergey Senozhatsky
has several fixes and cleaups for zram in the area of
zram_write_page(). A watchdog softlockup warning was eliminated
- "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin
Brodsky cleans up the pagetable destructor implementations. A rare
use-after-free race is fixed
- "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes
simplifies and cleans up the debugging code in the VMA merging
logic
- "Account page tables at all levels" from Kevin Brodsky cleans up
and regularizes the pagetable ctor/dtor handling. This results in
improvements in accounting accuracy
- "mm/damon: replace most damon_callback usages in sysfs with new
core functions" from SeongJae Park cleans up and generalizes
DAMON's sysfs file interface logic
- "mm/damon: enable page level properties based monitoring" from
SeongJae Park increases the amount of information which is
presented in response to DAMOS actions
- "mm/damon: remove DAMON debugfs interface" from SeongJae Park
removes DAMON's long-deprecated debugfs interfaces. Thus the
migration to sysfs is completed
- "mm/hugetlb: Refactor hugetlb allocation resv accounting" from
Peter Xu cleans up and generalizes the hugetlb reservation
accounting
- "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino
removes a never-used feature of the alloc_pages_bulk() interface
- "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park
extends DAMOS filters to support not only exclusion (rejecting),
but also inclusion (allowing) behavior
- "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi
introduces a new memory descriptor for zswap.zpool that currently
overlaps with struct page for now. This is part of the effort to
reduce the size of struct page and to enable dynamic allocation of
memory descriptors
- "mm, swap: rework of swap allocator locks" from Kairui Song redoes
and simplifies the swap allocator locking. A speedup of 400% was
demonstrated for one workload. As was a 35% reduction for kernel
build time with swap-on-zram
- "mm: update mips to use do_mmap(), make mmap_region() internal"
from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that
mmap_region() can be made MM-internal
- "mm/mglru: performance optimizations" from Yu Zhao fixes a few
MGLRU regressions and otherwise improves MGLRU performance
- "Docs/mm/damon: add tuning guide and misc updates" from SeongJae
Park updates DAMON documentation
- "Cleanup for memfd_create()" from Isaac Manjarres does that thing
- "mm: hugetlb+THP folio and migration cleanups" from David
Hildenbrand provides various cleanups in the areas of hugetlb
folios, THP folios and migration
- "Uncached buffered IO" from Jens Axboe implements the new
RWF_DONTCACHE flag which provides synchronous dropbehind for
pagecache reading and writing. To permite userspace to address
issues with massive buildup of useless pagecache when
reading/writing fast devices
- "selftests/mm: virtual_address_range: Reduce memory" from Thomas
Weißschuh fixes and optimizes some of the MM selftests"
* tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
mm/compaction: fix UBSAN shift-out-of-bounds warning
s390/mm: add missing ctor/dtor on page table upgrade
kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags()
tools: add VM_WARN_ON_VMG definition
mm/damon/core: use str_high_low() helper in damos_wmark_wait_us()
seqlock: add missing parameter documentation for raw_seqcount_try_begin()
mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh
mm/page_alloc: remove the incorrect and misleading comment
zram: remove zcomp_stream_put() from write_incompressible_page()
mm: separate move/undo parts from migrate_pages_batch()
mm/kfence: use str_write_read() helper in get_access_type()
selftests/mm/mkdirty: fix memory leak in test_uffdio_copy()
kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags()
selftests/mm: virtual_address_range: avoid reading from VM_IO mappings
selftests/mm: vm_util: split up /proc/self/smaps parsing
selftests/mm: virtual_address_range: unmap chunks after validation
selftests/mm: virtual_address_range: mmap() without PROT_WRITE
selftests/memfd/memfd_test: fix possible NULL pointer dereference
mm: add FGP_DONTCACHE folio creation flag
mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue
...
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
"Mainly individually changelogged singleton patches. The patch series
in this pull are:
- "lib min_heap: Improve min_heap safety, testing, and documentation"
from Kuan-Wei Chiu provides various tightenings to the min_heap
library code
- "xarray: extract __xa_cmpxchg_raw" from Tamir Duberstein preforms
some cleanup and Rust preparation in the xarray library code
- "Update reference to include/asm-<arch>" from Geert Uytterhoeven
fixes pathnames in some code comments
- "Converge on using secs_to_jiffies()" from Easwar Hariharan uses
the new secs_to_jiffies() in various places where that is
appropriate
- "ocfs2, dlmfs: convert to the new mount API" from Eric Sandeen
switches two filesystems to the new mount API
- "Convert ocfs2 to use folios" from Matthew Wilcox does that
- "Remove get_task_comm() and print task comm directly" from Yafang
Shao removes now-unneeded calls to get_task_comm() in various
places
- "squashfs: reduce memory usage and update docs" from Phillip
Lougher implements some memory savings in squashfs and performs
some maintainability work
- "lib: clarify comparison function requirements" from Kuan-Wei Chiu
tightens the sort code's behaviour and adds some maintenance work
- "nilfs2: protect busy buffer heads from being force-cleared" from
Ryusuke Konishi fixes an issues in nlifs when the fs is presented
with a corrupted image
- "nilfs2: fix kernel-doc comments for function return values" from
Ryusuke Konishi fixes some nilfs kerneldoc
- "nilfs2: fix issues with rename operations" from Ryusuke Konishi
addresses some nilfs BUG_ONs which syzbot was able to trigger
- "minmax.h: Cleanups and minor optimisations" from David Laight does
some maintenance work on the min/max library code
- "Fixes and cleanups to xarray" from Kemeng Shi does maintenance
work on the xarray library code"
* tag 'mm-nonmm-stable-2025-01-24-23-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (131 commits)
ocfs2: use str_yes_no() and str_no_yes() helper functions
include/linux/lz4.h: add some missing macros
Xarray: use xa_mark_t in xas_squash_marks() to keep code consistent
Xarray: remove repeat check in xas_squash_marks()
Xarray: distinguish large entries correctly in xas_split_alloc()
Xarray: move forward index correctly in xas_pause()
Xarray: do not return sibling entries from xas_find_marked()
ipc/util.c: complete the kernel-doc function descriptions
gcov: clang: use correct function param names
latencytop: use correct kernel-doc format for func params
minmax.h: remove some #defines that are only expanded once
minmax.h: simplify the variants of clamp()
minmax.h: move all the clamp() definitions after the min/max() ones
minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
minmax.h: reduce the #define expansion of min(), max() and clamp()
minmax.h: update some comments
minmax.h: add whitespace around operators and after commas
nilfs2: do not update mtime of renamed directory that is not moved
nilfs2: handle errors that nilfs_prepare_chunk() may return
CREDITS: fix spelling mistake
...
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In /proc/<pid>/ksm_stat, add two extra ksm involvement items including
KSM_mergeable and KSM_merge_any. It helps administrators to better know
the system's KSM behavior at process level.
ksm_merge_any: yes/no
whether the process'mm is added by prctl() into the candidate list
of KSM or not, and fully enabled at process level.
ksm_mergeable: yes/no
whether any VMAs of the process'mm are currently applicable to KSM.
Purpose
=======
These two items are just to improve the observability of KSM at process
level, so that users can know if a certain process has enabled KSM.
For example, if without these two items, when we look at
/proc/<pid>/ksm_stat and there's no merging pages found, We are not sure
whether it is because KSM was not enabled or because KSM did not
successfully merge any pages.
Although "mg" in /proc/<pid>/smaps indicate VM_MERGEABLE, it's opaque
and not very obvious for non professionals.
[akpm@linux-foundation.org: wording tweaks, per David and akpm]
Link: https://lkml.kernel.org/r/20250110174034304QOb8eDoqtFkp3_t8mqnqc@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Cc: Wang Yaxin <wang.yaxin@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Remove highest_bit and lowest_bit. After the HDD allocation path has been
removed, the only purpose of these two fields is to determine whether the
device is full or not, which can instead be determined by checking the
inuse_pages.
Link: https://lkml.kernel.org/r/20250113175732.48099-6-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chis Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickens <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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