NFS: add atomic_open for NFSv3 to handle O_TRUNC correctly.

With two clients, each with NFSv3 mounts of the same directory, the sequence:

client1 client2
ls -l afile

NFS: add atomic_open for NFSv3 to handle O_TRUNC correctly.

With two clients, each with NFSv3 mounts of the same directory, the sequence:

client1 client2
ls -l afile
echo hello there > afile
echo HELLO > afile
cat afile

will show
HELLO
there

because the O_TRUNC requested in the final 'echo' doesn't take effect.
This is because the "Negative dentry, just create a file" section in
lookup_open() assumes that the file *does* get created since the dentry
was negative, so it sets FMODE_CREATED, and this causes do_open() to
clear O_TRUNC and so the file doesn't get truncated.

Even mounting with -o lookupcache=none does not help as
nfs_neg_need_reval() always returns false if LOOKUP_CREATE is set.

This patch fixes the problem by providing an atomic_open inode operation
for NFSv3 (and v2). The code is largely the code from the branch in
lookup_open() when atomic_open is not provided. The significant change
is that the O_TRUNC flag is passed a new nfs_do_create() which add
'trunc' handling to nfs_create().

With this change we also optimise away an unnecessary LOOKUP before the
file is created.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

nfs: make nfs_set_verifier() safe for use in RCU pathwalk

nfs_set_verifier() relies upon dentry being pinned; if that's
the case, grabbing ->d_lock stabilizes ->d_parent and guarantees
that ->d_pare

nfs: make nfs_set_verifier() safe for use in RCU pathwalk

nfs_set_verifier() relies upon dentry being pinned; if that's
the case, grabbing ->d_lock stabilizes ->d_parent and guarantees
that ->d_parent points to a positive dentry. For something
we'd run into in RCU mode that is *not* true - dentry might've
been through dentry_kill() just as we grabbed ->d_lock, with
its parent going through the same just as we get to into
nfs_set_verifier_locked(). It might get to detaching inode
(and zeroing ->d_inode) before nfs_set_verifier_locked() gets
to fetching that; we get an oops as the result.

That can happen in nfs{,4} ->d_revalidate(); the call chain in
question is nfs_set_verifier_locked() <- nfs_set_verifier() <-
nfs_lookup_revalidate_delegated() <- nfs{,4}_do_lookup_revalidate().
We have checked that the parent had been positive, but that's
done before we get to nfs_set_verifier() and it's possible for
memory pressure to pick our dentry as eviction candidate by that
time. If that happens, back-to-back attempts to kill dentry and
its parent are quite normal. Sure, in case of eviction we'll
fail the ->d_seq check in the caller, but we need to survive
until we return there...

Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

show more ...

nfs: add new tracepoint at nfs4 revalidate entry point

Add a call to the v4 d_revalidate entrypoint, just like the v3 one.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Chuck Lever <

nfs: add new tracepoint at nfs4 revalidate entry point

Add a call to the v4 d_revalidate entrypoint, just like the v3 one.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

NFS: Use parent's objective cred in nfs_access_login_time()

The subjective cred (task->cred) can potentially be overridden and
subsquently freed in non-RCU context, which could lead to a panic if we

NFS: Use parent's objective cred in nfs_access_login_time()

The subjective cred (task->cred) can potentially be overridden and
subsquently freed in non-RCU context, which could lead to a panic if we
try to use it in cred_fscmp(). Use __task_cred(), which returns the
objective cred (task->real_cred) instead.

Fixes: 0eb43812c027 ("NFS: Clear the file access cache upon login")
Fixes: 5e9a7b9c2ea1 ("NFS: Fix up a sparse warning")

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

nfs: Convert nfs_symlink() to use a folio

Use the folio APIs, saving about four calls to compound_head().
Convert back to a page in each of the individual protocol implementations.

Signed-off-by: M

nfs: Convert nfs_symlink() to use a folio

Use the folio APIs, saving about four calls to compound_head().
Convert back to a page in each of the individual protocol implementations.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

nfs: fix redundant readdir request after get eof

When a directory contains 17 files (except . and ..), nfs client sends
a redundant readdir request after get eof.

A simple reproduce,
At NFS server,

nfs: fix redundant readdir request after get eof

When a directory contains 17 files (except . and ..), nfs client sends
a redundant readdir request after get eof.

A simple reproduce,
At NFS server, create a directory with 17 files under exported directory.
# mkdir test
# cd test
# for i in {0..16} ; do touch $i; done

At NFS client, no matter mounting through nfsv3 or nfsv4,
does ls (or ll) at the created test directory.

A tshark output likes following (for nfsv4),

# tshark -i eth0 tcp port 2049 -Tfields -e ip.src -e ip.dst -e nfs -e nfs.cookie4

srcip dstip SEQUENCE, PUTFH, READDIR 0
dstip srcip SEQUENCE PUTFH READDIR 909539109313539306,2108391201987888856,2305312124304486544,2566335452463141496,2978225129081509984,4263037479923412583,4304697173036510679,4666703455469210097,4759208201298769007,4776701232145978803,5338408478512081262,5949498658935544804,5971526429894832903,6294060338267709855,6528840566229532529,8600463293536422524,9223372036854775807
srcip dstip
srcip dstip SEQUENCE, PUTFH, READDIR 9223372036854775807
dstip srcip SEQUENCE PUTFH READDIR

The READDIR with cookie 9223372036854775807(0x7FFFFFFFFFFFFFFF) is redundant.

Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

NFS: Convert kmap_atomic() to kmap_local_folio()

kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().

Therefore, replace kmap_atomic() with kmap_local_folio() in
nfs_readdir_folio_arr

NFS: Convert kmap_atomic() to kmap_local_folio()

kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().

Therefore, replace kmap_atomic() with kmap_local_folio() in
nfs_readdir_folio_array_append().

kmap_atomic() disables page-faults and preemption (the latter only for
!PREEMPT_RT kernels), However, the code within the mapping/un-mapping in
nfs_readdir_folio_array_append() does not depend on the above-mentioned
side effects.

Therefore, a mere replacement of the old API with the new one is all that
is required (i.e., there is no need to explicitly add any calls to
pagefault_disable() and/or preempt_disable()).

Tested with (x)fstests in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel
with HIGHMEM64GB enabled.

Cc: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Fixes: ec108d3cc766 ("NFS: Convert readdir page array functions to use a folio")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

nfs: fix another case of NULL/IS_ERR confusion wrt folio pointers

Dan has been improving on the smatch error pointer checks, and pointed
at another case where the __filemap_get_folio() conversion to

nfs: fix another case of NULL/IS_ERR confusion wrt folio pointers

Dan has been improving on the smatch error pointer checks, and pointed
at another case where the __filemap_get_folio() conversion to error
pointers had been overlooked. This time because it was hidden behind
the filemap_grab_folio() helper function that is a wrapper around it.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

nfs: fix mis-merged __filemap_get_folio() error check

Fix another case of an incorrect check for the returned 'folio' value
from __filemap_get_folio().

The failure case used to return NULL, but was

nfs: fix mis-merged __filemap_get_folio() error check

Fix another case of an incorrect check for the returned 'folio' value
from __filemap_get_folio().

The failure case used to return NULL, but was changed by commit
66dabbb65d67 ("mm: return an ERR_PTR from __filemap_get_folio").

But in the meantime, commit ec108d3cc766 ("NFS: Convert readdir page
array functions to use a folio") added a new user of that function.

And my merge of the two did not fix this up correctly.

The ext4 merge had the same issue, but that one had been caught in
linux-next and got properly fixed while merging.

Fixes: 0127f25b5dfc ("Merge tag 'nfs-for-6.4-1' of git://git.linux-nfs.org/projects/anna/linux-nfs")
Cc: Anna Schumaker <anna@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

NFS: Convert readdir page array functions to use a folio

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFS: Convert the readdir array-of-pages into an array-of-folios

This patch only converts the actual array, but doesn't touch the
individual nfs_cache_array pages and related functions (that will be

NFS: Convert the readdir array-of-pages into an array-of-folios

This patch only converts the actual array, but doesn't touch the
individual nfs_cache_array pages and related functions (that will be
done in the next patch).

I also adjust the names of the fields in the nfs_readdir_descriptor to
say "folio" instead of "page".

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

NFS: Correct timing for assigning access cache timestamp

When the user's login time is newer than the cache's timestamp,
the original entry in the RB-tree will be replaced by a new entry.
Currently,

NFS: Correct timing for assigning access cache timestamp

When the user's login time is newer than the cache's timestamp,
the original entry in the RB-tree will be replaced by a new entry.
Currently, the timestamp is only set if the entry is not found in
the RB-tree, which can cause the timestamp to be undefined when
the entry exists. This may result in a significant increase in
ACCESS operations if the timestamp is set to zero.

Signed-off-by: Chengen Du <chengen.du@canonical.com>
Fixes: 0eb43812c027 ("NFS: Clear the file access cache upon login”)
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

fs/nfs: Replace kmap_atomic() with kmap_local_page() in dir.c

kmap_atomic() is deprecated in favor of kmap_local_page().

With kmap_local_page() the mappings are per thread, CPU local, can take
page

fs/nfs: Replace kmap_atomic() with kmap_local_page() in dir.c

kmap_atomic() is deprecated in favor of kmap_local_page().

With kmap_local_page() the mappings are per thread, CPU local, can take
page-faults, and can be called from any context (including interrupts).
Furthermore, the tasks can be preempted and, when they are scheduled to
run again, the kernel virtual addresses are restored and still valid.

kmap_atomic() is implemented like a kmap_local_page() which also disables
page-faults and preemption (the latter only for !PREEMPT_RT kernels,
otherwise it only disables migration).

The code within the mappings/un-mappings in the functions of dir.c don't
depend on the above-mentioned side effects of kmap_atomic(), so that mere
replacements of the old API with the new one is all that is required
(i.e., there is no need to explicitly add calls to pagefault_disable()
and/or preempt_disable()).

Therefore, replace kmap_atomic() with kmap_local_page() in fs/nfs/dir.c.

Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

fs: port ->permission() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is j

fs: port ->permission() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

show more ...

fs: port ->rename() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just

fs: port ->rename() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

show more ...

fs: port ->mknod() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just t

fs: port ->mknod() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

show more ...

fs: port ->mkdir() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just t

fs: port ->mkdir() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

show more ...

fs: port ->symlink() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just

fs: port ->symlink() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

show more ...

fs: port ->create() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just

fs: port ->create() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

show more ...

NFS: Fix up a sparse warning

sparse is warning about an incorrect RCU dereference.
fs/nfs/dir.c:2965:56: warning: incorrect type in argument 1 (different address spaces)
fs/nfs/dir.c:2965:56: exp

NFS: Fix up a sparse warning

sparse is warning about an incorrect RCU dereference.
fs/nfs/dir.c:2965:56: warning: incorrect type in argument 1 (different address spaces)
fs/nfs/dir.c:2965:56: expected struct cred const *
fs/nfs/dir.c:2965:56: got struct cred const [noderef] __rcu *const cred

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFS: Judge the file access cache's timestamp in rcu path

If the user's login time is newer than the cache's timestamp,
we expect the cache may be stale and need to clear.
The stale cache will remain

NFS: Judge the file access cache's timestamp in rcu path

If the user's login time is newer than the cache's timestamp,
we expect the cache may be stale and need to clear.
The stale cache will remain in the list's tail if no other
users operate on that inode.
Once the user accesses the inode, the stale cache will be
returned in rcu path.

Signed-off-by: Chengen Du <chengen.du@canonical.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFS: Trigger the "ls -l" readdir heuristic sooner

Since commit 1a34c8c9a49e ("NFS: Support larger readdir buffers") has
updated dtsize, and with recent improvements to the READDIRPLUS helper
heurist

NFS: Trigger the "ls -l" readdir heuristic sooner

Since commit 1a34c8c9a49e ("NFS: Support larger readdir buffers") has
updated dtsize, and with recent improvements to the READDIRPLUS helper
heuristic, the heuristic may not trigger until many dentries are emitted
to userspace. This will cause many thousands of GETATTR calls for "ls
-l" when the directory's pagecache has already been populated. This
manifests as poor performance for long directory listings after an
initially fast "ls -l".

Fix this by emitting only 17 entries for any first pass through the NFS
directory's ->iterate_shared(), which allows userpace to prime the
counters for the heuristic.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

NFS: Clear the file access cache upon login

POSIX typically only refreshes the user's supplementary group
information upon login. Since NFS servers may often refresh their
concept of the user supple

NFS: Clear the file access cache upon login

POSIX typically only refreshes the user's supplementary group
information upon login. Since NFS servers may often refresh their
concept of the user supplementary group membership at their own cadence,
it is possible for the NFS client's access cache to become stale due to
the user's group membership changing on the server after the user has
already logged in on the client.
While it is reasonable to expect that such group membership changes are
rare, and that we do not want to optimise the cache to accommodate them,
it is also not unreasonable for the user to expect that if they log out
and log back in again, that the staleness would clear up.

Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

show more ...

nfs: Remove redundant null checks before kfree

Fix the following coccicheck warning:
fs/nfs/dir.c:2494:2-7: WARNING:
NULL check before some freeing functions is not needed.

Signed-off-by: Yushan Zh

nfs: Remove redundant null checks before kfree

Fix the following coccicheck warning:
fs/nfs/dir.c:2494:2-7: WARNING:
NULL check before some freeing functions is not needed.

Signed-off-by: Yushan Zhou <katrinzhou@tencent.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

show more ...

nfs_finish_open(): don't open-code file_inode()

Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>