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Merge tag 'kernel-6.19-rc1.cred' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull cred guard updates from Christian Brauner:
"This contains substantial credential infrastructure improvements
adding guard-based credential management that simplifies code and
eliminates manual reference counting in many subsystems.
Features:
- Kernel Credential Guards
Add with_kernel_creds() and scoped_with_kernel_creds() guards that
allow using the kernel credentials without allocating and copying
them. This was requested by Linus after seeing repeated
prepare_kernel_creds() calls that duplicate the kernel credentials
only to drop them again later.
The new guards completely avoid the allocation and never expose the
temporary variable to hold the kernel credentials anywhere in
callers.
- Generic Credential Guards
Add scoped_with_creds() guards for the common override_creds() and
revert_creds() pattern. This builds on earlier work that made
override_creds()/revert_creds() completely reference count free.
- Prepare Credential Guards
Add prepare credential guards for the more complex pattern of
preparing a new set of credentials and overriding the current
credentials with them:
- prepare_creds()
- modify new creds
- override_creds()
- revert_creds()
- put_cred()
Cleanups:
- Make init_cred static since it should not be directly accessed
- Add kernel_cred() helper to properly access the kernel credentials
- Fix scoped_class() macro that was introduced two cycles ago
- coredump: split out do_coredump() from vfs_coredump() for cleaner
credential handling
- coredump: move revert_cred() before coredump_cleanup()
- coredump: mark struct mm_struct as const
- coredump: pass struct linux_binfmt as const
- sev-dev: use guard for path"
* tag 'kernel-6.19-rc1.cred' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (36 commits)
trace: use override credential guard
trace: use prepare credential guard
coredump: use override credential guard
coredump: use prepare credential guard
coredump: split out do_coredump() from vfs_coredump()
coredump: mark struct mm_struct as const
coredump: pass struct linux_binfmt as const
coredump: move revert_cred() before coredump_cleanup()
sev-dev: use override credential guards
sev-dev: use prepare credential guard
sev-dev: use guard for path
cred: add prepare credential guard
net/dns_resolver: use credential guards in dns_query()
cgroup: use credential guards in cgroup_attach_permissions()
act: use credential guards in acct_write_process()
smb: use credential guards in cifs_get_spnego_key()
nfs: use credential guards in nfs_idmap_get_key()
nfs: use credential guards in nfs_local_call_write()
nfs: use credential guards in nfs_local_call_read()
erofs: use credential guards
...
From https://lore.kernel.org/linux-nfs/aQHASIumLJyOoZGH@infradead.org/
On Wed, Oct 29, 2025 at 12:20:40AM -0700, Christoph Hellwig wrote:
> On Mon, Oct 27, 2025 at 12:18:30PM -0400, Mike Snitzer wrote:
> > LOCALIO's misaligned DIO will issue head/tail followed by O_DIRECT
> > middle (via AIO completion of that aligned middle). So out of order
> > relative to file offset.
>
> That's in general a really bad idea. It will obviously work, but
> both on SSDs and out of place write file systems it is a sure way
> to increase your garbage collection overhead a lot down the line.
Fix this by never issuing misaligned DIO out of order. This fix means
the DIO-aligned middle will only use AIO completion if there is no
misaligned end segment. Otherwise, all 3 segments of a misaligned DIO
will be issued without AIO completion to ensure file offset increases
properly for all partial READ or WRITE situations.
Factoring out nfs_local_iter_setup() helps standardize repetitive
nfs_local_iters_setup_dio() code and is inspired by cleanup work that
Chuck Lever did on the NFSD Direct code.
Fixes: c817248fc8 ("nfs/localio: add proper O_DIRECT support for READ and WRITE")
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
LOCALIO's misaligned DIO WRITE support requires synchronous IO for any
misaligned head and/or tail that are issued using buffered IO. In
addition, it is important that the O_DIRECT middle be on stable
storage upon its completion via AIO.
Otherwise, a misaligned DIO WRITE could mix buffered IO for the
head/tail and direct IO for the DIO-aligned middle -- which could lead
to problems associated with deferred writes to stable storage (such as
out of order partial completions causing incorrect advancement of the
file's offset, etc).
Fixes: c817248fc8 ("nfs/localio: add proper O_DIRECT support for READ and WRITE")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Misaligned DIO read can be split into 3 IOs, must handle potential for
short read from each component IO (follows same pattern used for
handling partial writes, except upper layer read code handles advancing
offset before retry).
Fixes: c817248fc8 ("nfs/localio: add proper O_DIRECT support for READ and WRITE")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Improve completion handling of as many as 3 IOs associated with each
misaligned DIO by using a atomic_t to track completion of each IO.
Update nfs_local_pgio_done() to use precise atomic_t accounting for
remaining iov_iter (up to 3) associated with each iocb, so that each
NFS LOCALIO pgio header is only released after all IOs have completed.
But also allow early return if/when a short read or write occurs.
Fixes reported BUG: KASAN: slab-use-after-free in nfs_local_call_read:
https://lore.kernel.org/linux-nfs/aPSvi5Yr2lGOh5Jh@dell-per750-06-vm-07.rhts.eng.pek2.redhat.com/
Reported-by: Yongcheng Yang <yoyang@redhat.com>
Fixes: c817248fc8 ("nfs/localio: add proper O_DIRECT support for READ and WRITE")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Each filesystem is meant to fallback to retrying DIO in terms buffered
IO when it might encounter -ENOTBLK when issuing DIO (which can happen
if the VFS cannot invalidate the page cache).
So NFS doesn't need special handling for -ENOTBLK.
Also, explicitly initialize a couple DIO related iocb members rather
than simply rely on data structure zeroing.
Fixes: c817248fc8 ("nfs/localio: add proper O_DIRECT support for READ and WRITE")
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-f_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull file->f_path constification from Al Viro:
"Only one thing was modifying ->f_path of an opened file - acct(2).
Massaging that away and constifying a bunch of struct path * arguments
in functions that might be given &file->f_path ends up with the
situation where we can turn ->f_path into an anon union of const
struct path f_path and struct path __f_path, the latter modified only
in a few places in fs/{file_table,open,namei}.c, all for struct file
instances that are yet to be opened"
* tag 'pull-f_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (23 commits)
Have cc(1) catch attempts to modify ->f_path
kernel/acct.c: saner struct file treatment
configfs:get_target() - release path as soon as we grab configfs_item reference
apparmor/af_unix: constify struct path * arguments
ovl_is_real_file: constify realpath argument
ovl_sync_file(): constify path argument
ovl_lower_dir(): constify path argument
ovl_get_verity_digest(): constify path argument
ovl_validate_verity(): constify {meta,data}path arguments
ovl_ensure_verity_loaded(): constify datapath argument
ksmbd_vfs_set_init_posix_acl(): constify path argument
ksmbd_vfs_inherit_posix_acl(): constify path argument
ksmbd_vfs_kern_path_unlock(): constify path argument
ksmbd_vfs_path_lookup_locked(): root_share_path can be const struct path *
check_export(): constify path argument
export_operations->open(): constify path argument
rqst_exp_get_by_name(): constify path argument
nfs: constify path argument of __vfs_getattr()
bpf...d_path(): constify path argument
done_path_create(): constify path argument
...
Add nfs_local_dio_class and use it to create nfs_local_dio_read,
nfs_local_dio_write and nfs_local_dio_misaligned trace events.
These trace events show how NFS LOCALIO splits a given misaligned
IO into a mix of misaligned head and/or tail extents and a DIO-aligned
middle extent. The misaligned head and/or tail extents are issued
using buffered IO and the DIO-aligned middle is issued using O_DIRECT.
This combination of trace events is useful for LOCALIO DIO READs:
echo 1 > /sys/kernel/tracing/events/nfs/nfs_local_dio_read/enable
echo 1 > /sys/kernel/tracing/events/nfs/nfs_local_dio_misaligned/enable
echo 1 > /sys/kernel/tracing/events/nfs/nfs_initiate_read/enable
echo 1 > /sys/kernel/tracing/events/nfs/nfs_readpage_done/enable
echo 1 > /sys/kernel/tracing/events/xfs/xfs_file_direct_read/enable
This combination of trace events is useful for LOCALIO DIO WRITEs:
echo 1 > /sys/kernel/tracing/events/nfs/nfs_local_dio_write/enable
echo 1 > /sys/kernel/tracing/events/nfs/nfs_local_dio_misaligned/enable
echo 1 > /sys/kernel/tracing/events/nfs/nfs_initiate_write/enable
echo 1 > /sys/kernel/tracing/events/nfs/nfs_writeback_done/enable
echo 1 > /sys/kernel/tracing/events/xfs/xfs_file_direct_write/enable
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Because the NFS client will already happily handle misaligned O_DIRECT
IO (by sending it out to NFSD via RPC) this commit's new capabilities
are for the benefit of LOCALIO.
LOCALIO will make best effort to transform misaligned IO to
DIO-aligned extents when possible.
LOCALIO's READ and WRITE DIO that is misaligned will be split into as
many as 3 component IOs (@start, @middle and @end) as needed -- IFF
the @middle extent is verified to be DIO-aligned, and then the @start
and/or @end are misaligned (due to each being a partial page).
Otherwise if the @middle isn't DIO-aligned the code will fallback to
issuing only a single contiguous buffered IO.
The @middle is only DIO-aligned if both the memory and on-disk offsets
for the IO are aligned relative to the underlying local filesystem's
block device limits (@dma_alignment and @logical_block_size
respectively).
The misaligned @start and/or @end extents are issued using buffered IO
and the DIO-aligned @middle is issued using O_DIRECT. The @start and
@end IOs are issued first using buffered IO with IOCB_SYNC and then
the @middle is issued last using direct IO with async completion (AIO).
This out of order IO completion means that LOCALIO's IO completion
code (nfs_local_read_done and nfs_local_write_done) is only called for
the IO's last associated iov_iter completion. And in the case of
DIO-aligned @middle it completes last using AIO. nfs_local_pgio_done()
is updated to handle piece-wise partial completion of each iov_iter.
This implementation for LOCALIO's misaligned DIO handling uses 3
iov_iter that share the same backing pages in their bio_vecs (so
unfortunately 'struct nfs_local_kiocb' has 3 instead of only 1).
[Reducing LOCALIO's per-IO (struct nfs_local_kiocb) memory use can be
explored in the future. One logical progression to improve this code,
and eliminate explicit loops over up to 3 iov_iter, is by extending
'struct iov_iter' to support iov_iter_clone() and iov_iter_chain()
interfaces that are comparable to what 'struct bio' is able to support
in the block layer. But even that wouldn't avoid the need to
allocate/use up to 3 iov_iter]
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
The goal of this commit's various refactoring is to have LOCALIO's per
IO initialization occur in process context so that we don't get into a
situation where IO fails to be issued from workqueue (e.g. due to lack
of memory, etc). Better to have LOCALIO's iocb initialization fail
early.
There isn't immediate need but this commit makes it possible for
LOCALIO to fallback to NFS pagelist code in process context to allow
for immediate retry over RPC.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
nfs_local_iter_init() is updated to follow the same pattern to
initializing LOCALIO's iov_iter_bvec as was established by
nfsd_iter_read().
Other LOCALIO iocb initialization refactoring in this commit offers
incremental cleanup that will be taken further by the next commit.
No functional change.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Add nfsd_file_dio_alignment and use it to avoid issuing misaligned IO
using O_DIRECT. Any misaligned DIO falls back to using buffered IO.
Because misaligned DIO is now handled safely, remove the nfs modparam
'localio_O_DIRECT_semantics' that was added to require users opt-in to
the requirement that all O_DIRECT be properly DIO-aligned.
Also, introduce nfs_iov_iter_aligned_bvec() which is a variant of
iov_iter_aligned_bvec() that also verifies the offset associated with
an iov_iter is DIO-aligned. NOTE: in a parallel effort,
iov_iter_aligned_bvec() is being removed along with
iov_iter_is_aligned().
Lastly, add pr_info_ratelimited if underlying filesystem returns
-EINVAL because it was made to try O_DIRECT for IO that is not
DIO-aligned (shouldn't happen, so its best to be louder if it does).
Fixes: 3feec68563 ("nfs/localio: add direct IO enablement with sync and async IO support")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Always trigger trace event when LOCALIO opens a file.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Previously nfs_local_probe() was made to disable and then attempt to
re-enable LOCALIO (via LOCALIO protocol handshake) if/when it was
called and LOCALIO already enabled.
Vague memory for _why_ this was the case is that this was useful
if/when a local NFS server were to be restarted with a local NFS
client connected to it.
But as it happens this causes an absurd amount of LOCALIO flapping
which has a side-effect of too much IO being needlessly sent to NFSD
(using RPC over the loopback network interface). This is the
definition of "serious performance loss" (that negates the point of
having LOCALIO).
So remove this mis-optimization for re-enabling LOCALIO if/when an NFS
server is restarted (which is an extremely rare thing to do). Will
revisit testing that scenario again but in the meantime this patch
restores the full benefit of LOCALIO.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Otherwise if the nfsd filecache code releases the nfsd_file
immediately, it can trigger the BUG_ON(cred == current->cred) in
__put_cred() when it puts the nfsd_file->nf_file->f-cred.
Fixes: b9f5dd57f4 ("nfs/localio: use dedicated workqueues for filesystem read and write")
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20250807164938.2395136-1-smayhew@redhat.com
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
The usage of read_seqbegin_or_lock() in nfs_copy_boot_verifier()
is wrong. "seq" is always even and thus "or_lock" has no effect.
nfs_copy_boot_verifier() just copies 8 bytes and is supposed to be
very rare operation, so we do not need the adaptive locking in this case.
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Link: https://lore.kernel.org/r/20250731081038.3478-1-lirongqing@baidu.com
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Instead of calling xchg() and unrcu_pointer() before
nfsd_file_put_local(), we now pass pointer to the __rcu pointer and call
xchg() and unrcu_pointer() inside that function.
Where unrcu_pointer() is currently called the internals of "struct
nfsd_file" are not known and that causes older compilers such as gcc-8
to complain.
In some cases we have a __kernel (aka normal) pointer not an __rcu
pointer so we need to cast it to __rcu first. This is strictly a
weakening so no information is lost. Somewhat surprisingly, this cast
is accepted by gcc-8.
This has the pleasing result that the cmpxchg() which sets ro_file and
rw_file, and also the xchg() which clears them, are both now in the nfsd
code.
Reported-by: Pali Rohár <pali@kernel.org>
Reported-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Fixes: 86e0041225 ("nfs: cache all open LOCALIO nfsd_file(s) in client")
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
The nfsd_localio_operations structure contains nfsd_file_get() to get a
reference to an nfsd_file. This is only used in one place, where
nfsd_open_local_fh() is also used.
This patch combines the two, calling nfsd_open_local_fh() passing a
pointer to where the nfsd_file pointer might be stored. If there is a
pointer there an nfsd_file_get() can get a reference, that reference is
returned. If not a new nfsd_file is acquired, stored at the pointer,
and returned. When we store a reference we also increase the refcount
on the net, as that refcount is decrements when we clear the stored
pointer.
We now get an extra reference *before* storing the new nfsd_file at the
given location. This avoids possible races with the nfsd_file being
freed before the final reference can be taken.
This patch moves the rcu_dereference() needed after fetching from
ro_file or rw_file into the nfsd code where the 'struct nfs_file' is
fully defined. This avoids an error reported by older versions of gcc
such as gcc-8 which complain about rcu_dereference() use in contexts
where the structure (which will supposedly be accessed) is not fully
defined.
Reported-by: Pali Rohár <pali@kernel.org>
Reported-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Fixes: 86e0041225 ("nfs: cache all open LOCALIO nfsd_file(s) in client")
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Having separate nfsd_file_put and nfsd_file_put_local in struct
nfsd_localio_operations doesn't make much sense. The difference is that
nfsd_file_put doesn't drop a reference to the nfs_net which is what
keeps nfsd from shutting down.
Currently, if nfsd tries to shutdown it will invalidate the files stored
in the list from the nfs_uuid and this will drop all references to the
nfsd net that the client holds. But the client could still hold some
references to nfsd_files for active IO. So nfsd might think is has
completely shut down local IO, but hasn't and has no way to wait for
those active IO requests to complete.
So this patch changes nfsd_file_get to nfsd_file_get_local and has it
increase the ref count on the nfsd net and it replaces all calls to
->nfsd_put_file to ->nfsd_put_file_local.
It also changes ->nfsd_open_local_fh to return with the refcount on the
net elevated precisely when a valid nfsd_file is returned.
This means that whenever the client holds a valid nfsd_file, there will
be an associated count on the nfsd net, and so the count can only reach
zero when all nfsd_files have been returned.
nfs_local_file_put() is changed to call nfs_to_nfsd_file_put_local()
instead of replacing calls to one with calls to the other because this
will help a later patch which changes nfs_to_nfsd_file_put_local() to
take an __rcu pointer while nfs_local_file_put() doesn't.
Fixes: 86e0041225 ("nfs: cache all open LOCALIO nfsd_file(s) in client")
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Rather than using nfs_uuid.lock to protect installing
a new ro_file or rw_file, change to use cmpxchg().
Removing the file already uses xchg() so this improves symmetry
and also makes the code a little simpler.
Also remove the optimisation of not taking the lock, and not removing
the nfs_file_localio from the linked list, when both ->ro_file and
->rw_file are already NULL. Given that ->nfs_uuid was not NULL, it is
extremely unlikely that neither ->ro_file or ->rw_file is NULL so
this optimisation can be of little value and it complicates
understanding of the code - why can the list_del_init() be skipped?
Finally, move the assignment of NULL to ->nfs_uuid until after
the last action on the nfs_file_localio (the list_del_init). As soon as
this is NULL a racing nfs_close_local_fh() can bypass all the locking
and go on to free the nfs_file_localio, so we must be certain to be
finished with it first.
Fixes: 86e0041225 ("nfs: cache all open LOCALIO nfsd_file(s) in client")
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
It was reported that NFS client mounts of AWS Elastic File System
(EFS) volumes is slow, this is because the AWS firewall disallows
LOCALIO (because it doesn't consider the use of NFS_LOCALIO_PROGRAM
valid), see: https://bugzilla.redhat.com/show_bug.cgi?id=2335129
Switch to performing the LOCALIO probe asynchronously to address the
potential for the NFS LOCALIO protocol being disallowed and/or slowed
by the remote server's response.
While at it, fix nfs_local_probe_async() to always take/put a
reference on the nfs_client that is using the LOCALIO protocol.
Also, unexport the nfs_local_probe() symbol and make it private to
fs/nfs/localio.c
This change has the side-effect of initially issuing reads, writes and
commits over the wire via SUNRPC until the LOCALIO probe completes.
Suggested-by: Jeff Layton <jlayton@kernel.org> # to always probe async
Fixes: 76d4cb6345 ("nfs: probe for LOCALIO when v4 client reconnects to server")
Cc: stable@vger.kernel.org # 6.14+
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Once the clp->cl_uuid.lock has been dropped, another CPU could come in
and free the struct nfsd_file that was just added. To prevent that from
happening, take the RCU read lock before dropping the spin lock.
Fixes: 86e0041225 ("nfs: cache all open LOCALIO nfsd_file(s) in client")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
nfs4_stat_to_errno() expects a NFSv4 error code as an argument and
returns a POSIX errno.
The problem is LOCALIO is passing nfs4_stat_to_errno() the POSIX errno
return values from filp->f_op->read_iter(), filp->f_op->write_iter()
and vfs_fsync_range().
So the POSIX errno that nfs_local_pgio_done() and
nfs_local_commit_done() are passing to nfs4_stat_to_errno() are
failing to match any NFSv4 error code, which results in
nfs4_stat_to_errno() defaulting to returning -EREMOTEIO. This causes
assertions in upper layers due to -EREMOTEIO not being a valid NFSv4
error code.
Fix this by updating nfs_local_pgio_done() and nfs_local_commit_done()
to use the new nfs_localio_errno_to_nfs4_stat() to map a POSIX errno
to an NFSv4 error code.
Care was taken to factor out nfs4_errtbl_common[] to avoid duplicating
the same NFS error to errno table. nfs4_errtbl_common[] is checked
first by both nfs4_stat_to_errno and nfs_localio_errno_to_nfs4_stat
before they check their own more specialized tables (nfs4_errtbl[] and
nfs4_errtbl_localio[] respectively).
While auditing the associated error mapping tables, the (ab)use of -1
for the last table entry was removed in favor of using ARRAY_SIZE to
iterate the nfs_errtbl[] and nfs4_errtbl[]. And 'errno_NFSERR_IO' was
removed because it caused needless obfuscation.
Fixes: 70ba381e1a ("nfs: add LOCALIO support")
Reported-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Introduce nfs_local_probe_async() for the NFS client to initiate
if/when it reconnects with server. For NFSv4 it is a simple matter to
call nfs_local_probe_async() from nfs4_do_reclaim (during NFSv4
grace).
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Remove nfs_local_enable and nfs_local_disable, instead use
nfs_localio_enable_client and nfs_localio_disable_client.
Discontinue use of the NFS_CS_LOCAL_IO bit in the nfs_client struct's
cl_flags to reflect that LOCALIO is enabled; instead just test if the
net member of the nfs_uuid_t struct is set.
Also remove NFS_CS_LOCAL_IO.
Lastly, remove trace_nfs_local_enable and trace_nfs_local_disable
because comparable traces are available from nfs_localio.ko.
Suggested-by: NeilBrown <neilb@suse.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
This commit switches from leaning heavily on NFSD's filecache (in
terms of GC'd nfsd_files) back to caching nfsd_files in the
client. A later commit will add the callback mechanism needed to
allow NFSD to force the NFS client to cleanup all cached nfsd_files.
Add nfs_fh_localio_init() and 'struct nfs_fh_localio' to cache opened
nfsd_file(s) (both a RO and RW nfsd_file is able to be opened and
cached for a given nfs_fh).
Update nfs_local_open_fh() to cache the nfsd_file once it is opened
using __nfs_local_open_fh().
Introduce nfs_close_local_fh() to clear the cached open nfsd_files and
call nfs_to_nfsd_file_put_local().
Refcounting is such that:
- nfs_local_open_fh() is paired with nfs_close_local_fh().
- __nfs_local_open_fh() is paired with nfs_to_nfsd_file_put_local().
- nfs_local_file_get() is paired with nfs_local_file_put().
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Remove cl_localio_lock from 'struct nfs_client' in favor of adding a
lock to the nfs_uuid_t struct (which is embedded in each nfs_client).
Push nfs_local_{enable,disable} implementation down to nfs_common.
Those methods now call nfs_localio_{enable,disable}_client.
This allows implementing nfs_localio_invalidate_clients in terms of
nfs_localio_disable_client.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Rename nfs_uuid_invalidate_one_client to nfs_localio_disable_client.
Rename nfs_uuid_invalidate_clients to nfs_localio_invalidate_clients.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
This commit simply adds the required O_DIRECT plumbing. It doesn't
address the fact that NFS doesn't ensure all writes are page aligned
(nor device logical block size aligned as required by O_DIRECT).
Because NFS will read-modify-write for IO that isn't aligned, LOCALIO
will not use O_DIRECT semantics by default if/when an application
requests the use of O_DIRECT. Allow the use of O_DIRECT semantics by:
1: Adding a flag to the nfs_pgio_header struct to allow the NFS
O_DIRECT layer to signal that O_DIRECT was used by the application
2: Adding a 'localio_O_DIRECT_semantics' NFS module parameter that
when enabled will cause LOCALIO to use O_DIRECT semantics (this may
cause IO to fail if applications do not properly align their IO).
This commit is derived from code developed by Weston Andros Adamson.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Otherwise memory corruption can occur due to NFSv3 LOCALIO reads
leaving garbage in res.replen:
- nfs3_read_done() copies that into server->read_hdrsize; from there
nfs3_proc_read_setup() copies it to args.replen in new requests.
- nfs3_xdr_enc_read3args() passes that to rpc_prepare_reply_pages()
which includes it in hdrsize for xdr_init_pages, so that rq_rcv_buf
contains a ridiculous len.
- This is copied to rq_private_buf and xs_read_stream_request()
eventually passes the kvec to sock_recvmsg() which receives incoming
data into entirely the wrong place.
This is easily reproduced with NFSv3 LOCALIO that is servicing reads
when it is made to pivot back to using normal RPC. This switch back
to using normal NFSv3 with RPC can occur for a few reasons but this
issue was exposed with a test that stops and then restarts the NFSv3
server while LOCALIO is performing heavy read IO.
Fixes: 70ba381e1a ("nfs: add LOCALIO support")
Reported-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Co-developed-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Push the read_iter and write_iter availability checks down to
nfs_do_local_read and nfs_do_local_write respectively.
This eliminates a redundant nfs_to->nfsd_file_file() call.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
nfs_local_commit() doesn't need async cleanup of nfs_local_fsync_ctx,
so there is no need to use a kref.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
nfs_writeback_done() will take care of suid/sgid corner case.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Fix the possibility of racing nfs_local_probe() resulting in:
list_add double add: new=ffff8b99707f9f58, prev=ffff8b99707f9f58, next=ffffffffc0f30000.
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:35!
Add nfs_uuid_init() to properly initialize all nfs_uuid_t members
(particularly its list_head).
Switch to returning bool from nfs_uuid_begin(), returns false if
nfs_uuid_t is already in-use (its list_head is on a list). Update
nfs_local_probe() to return early if the nfs_client's cl_uuid
(nfs_uuid_t) is in-use.
Also, switch nfs_uuid_begin() from using list_add_tail_rcu() to
list_add_tail() -- rculist was used in an earlier version of the
localio code that had a lockless nfs_uuid_lookup interface.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Add nfs_to_nfsd_file_put_local() interface to fix race with nfsd
module unload. Similarly, use RCU around nfs_open_local_fh()'s error
path call to nfs_to->nfsd_serv_put(). Holding RCU ensures that NFS
will safely _call and return_ from its nfs_to calls into the NFSD
functions nfsd_file_put_local() and nfsd_serv_put().
Otherwise, if RCU isn't used then there is a narrow window when NFS's
reference for the nfsd_file and nfsd_serv are dropped and the NFSD
module could be unloaded, which could result in a crash from the
return instruction for either nfs_to->nfsd_file_put_local() or
nfs_to->nfsd_serv_put().
Reported-by: NeilBrown <neilb@suse.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
The header files linux/module.h is included twice in localio.c,
so one inclusion of each can be removed.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=11073
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
The LOCALIO auxiliary RPC protocol consists of a single "UUID_IS_LOCAL"
RPC method that allows the Linux NFS client to verify the local Linux
NFS server can see the nonce (single-use UUID) the client generated and
made available in nfs_common for subsequent lookup and verification
by the NFS server. If matched, the NFS server populates members in the
nfs_uuid_t struct. The NFS client then transfers these nfs_uuid_t
struct member pointers to the nfs_client struct and cleans up the
nfs_uuid_t struct. See: fs/nfs/localio.c:nfs_local_probe()
This protocol isn't part of an IETF standard, nor does it need to be
considering it is Linux-to-Linux auxiliary RPC protocol that amounts
to an implementation detail.
Localio is only supported when UNIX-style authentication (AUTH_UNIX, aka
AUTH_SYS) is used (enforced by fs/nfs/localio.c:nfs_local_probe()).
The UUID_IS_LOCAL method encodes the client generated uuid_t in terms of
the fixed UUID_SIZE (16 bytes). The fixed size opaque encode and decode
XDR methods are used instead of the less efficient variable sized
methods.
Having a nonce (single-use uuid) is better than using the same uuid
for the life of the server, and sending it proactively by client
rather than reactively by the server is also safer.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Co-developed-by: NeilBrown <neilb@suse.de>
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
For localio access, don't call filesystem read() and write() routines
directly. This solves two problems:
1) localio writes need to use a normal (non-memreclaim) unbound
workqueue. This avoids imposing new requirements on how underlying
filesystems process frontend IO, which would cause a large amount
of work to update all filesystems. Without this change, when XFS
starts getting low on space, XFS flushes work on a non-memreclaim
work queue, which causes a priority inversion problem:
00573 workqueue: WQ_MEM_RECLAIM writeback:wb_workfn is flushing !WQ_MEM_RECLAIM xfs-sync/vdc:xfs_flush_inodes_worker
00573 WARNING: CPU: 6 PID: 8525 at kernel/workqueue.c:3706 check_flush_dependency+0x2a4/0x328
00573 Modules linked in:
00573 CPU: 6 PID: 8525 Comm: kworker/u71:5 Not tainted 6.10.0-rc3-ktest-00032-g2b0a133403ab #18502
00573 Hardware name: linux,dummy-virt (DT)
00573 Workqueue: writeback wb_workfn (flush-0:33)
00573 pstate: 400010c5 (nZcv daIF -PAN -UAO -TCO -DIT +SSBS BTYPE=--)
00573 pc : check_flush_dependency+0x2a4/0x328
00573 lr : check_flush_dependency+0x2a4/0x328
00573 sp : ffff0000c5f06bb0
00573 x29: ffff0000c5f06bb0 x28: ffff0000c998a908 x27: 1fffe00019331521
00573 x26: ffff0000d0620900 x25: ffff0000c5f06ca0 x24: ffff8000828848c0
00573 x23: 1fffe00018be0d8e x22: ffff0000c1210000 x21: ffff0000c75fde00
00573 x20: ffff800080bfd258 x19: ffff0000cad63400 x18: ffff0000cd3a4810
00573 x17: 0000000000000000 x16: 0000000000000000 x15: ffff800080508d98
00573 x14: 0000000000000000 x13: 204d49414c434552 x12: 1fffe0001b6eeab2
00573 x11: ffff60001b6eeab2 x10: dfff800000000000 x9 : ffff60001b6eeab3
00573 x8 : 0000000000000001 x7 : 00009fffe491154e x6 : ffff0000db775593
00573 x5 : ffff0000db775590 x4 : ffff0000db775590 x3 : 0000000000000000
00573 x2 : 0000000000000027 x1 : ffff600018be0d62 x0 : dfff800000000000
00573 Call trace:
00573 check_flush_dependency+0x2a4/0x328
00573 __flush_work+0x184/0x5c8
00573 flush_work+0x18/0x28
00573 xfs_flush_inodes+0x68/0x88
00573 xfs_file_buffered_write+0x128/0x6f0
00573 xfs_file_write_iter+0x358/0x448
00573 nfs_local_doio+0x854/0x1568
00573 nfs_initiate_pgio+0x214/0x418
00573 nfs_generic_pg_pgios+0x304/0x480
00573 nfs_pageio_doio+0xe8/0x240
00573 nfs_pageio_complete+0x160/0x480
00573 nfs_writepages+0x300/0x4f0
00573 do_writepages+0x12c/0x4a0
00573 __writeback_single_inode+0xd4/0xa68
00573 writeback_sb_inodes+0x470/0xcb0
00573 __writeback_inodes_wb+0xb0/0x1d0
00573 wb_writeback+0x594/0x808
00573 wb_workfn+0x5e8/0x9e0
00573 process_scheduled_works+0x53c/0xd90
00573 worker_thread+0x370/0x8c8
00573 kthread+0x258/0x2e8
00573 ret_from_fork+0x10/0x20
2) Some filesystem writeback routines can end up taking up a lot of
stack space (particularly XFS). Instead of risking running over
due to the extra overhead from the NFS stack, we should just call
these routines from a workqueue job. Since we need to do this to
address 1) above we're able to avoid possibly blowing the stack
"for free".
Use of dedicated workqueues improves performance over using the
system_unbound_wq.
Also, the creds used to open the file are used to override_creds() in
both nfs_local_call_read() and nfs_local_call_write() -- otherwise the
workqueue could have elevated capabilities (which the caller may not).
Lastly, care is taken to set PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO in
nfs_do_local_write() to avoid writeback deadlocks.
The PF_LOCAL_THROTTLE flag prevents deadlocks in balance_dirty_pages()
by causing writes to only be throttled against other writes to the
same bdi (it keeps the throttling local). Normally all writes to
bdi(s) are throttled equally (after throughput factors are allowed
for).
The PF_MEMALLOC_NOIO flag prevents the lower filesystem IO from
causing memory reclaim to re-enter filesystems or IO devices and so
prevents deadlocks from occuring where IO that cleans pages is
waiting on IO to complete.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Co-developed-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Co-developed-by: NeilBrown <neilb@suse.de>
Signed-off-by: NeilBrown <neilb@suse.de> # eliminated wait_for_completion
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Add client support for bypassing NFS for localhost reads, writes, and
commits. This is only useful when the client and the server are
running on the same host.
nfs_local_probe() is stubbed out, later commits will enable client and
server handshake via a Linux-only LOCALIO auxiliary RPC protocol.
This has dynamic binding with the nfsd module (via nfs_localio module
which is part of nfs_common). LOCALIO will only work if nfsd is
already loaded.
The "localio_enabled" nfs kernel module parameter can be used to
disable and enable the ability to use LOCALIO support.
CONFIG_NFS_LOCALIO enables NFS client support for LOCALIO.
Lastly, LOCALIO uses an nfsd_file to initiate all IO. To make proper
use of nfsd_file (and nfsd's filecache) its lifetime (duration before
nfsd_file_put is called) must extend until after commit, read and
write operations. So rather than immediately drop the nfsd_file
reference in nfs_local_open_fh(), that doesn't happen until
nfs_local_pgio_release() for read/write and not until
nfs_local_release_commit_data() for commit. The same applies to the
reference held on nfsd's nn->nfsd_serv. Both objects' lifetimes and
associated references are managed through calls to
nfs_to->nfsd_file_put_local().
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Co-developed-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de> # nfs_open_local_fh
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Linus Torvalds
Mike Snitzer
Christian Brauner
Al Viro
Scott Mayhew
Li RongQing
NeilBrown
Trond Myklebust
NeilBrown
Mike Snitzer
Yang Li
Weston Andros Adamson