NFSv4: Fix revalidation of dentries with delegations

If a dentry was not initially looked up while we were holding a
delegation, then we do still need to revalidate that it still holds
the same name

NFSv4: Fix revalidation of dentries with delegations

If a dentry was not initially looked up while we were holding a
delegation, then we do still need to revalidate that it still holds
the same name. If there are multiple hard links to the same file,
then all the hard links need validation.

Reported-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
[Anna: Put nfs_unset_verifier_delegated() under CONFIG_NFS_V4]
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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NFS: Fix up directory verifier races

In order to avoid having our dentry revalidation race with an update
of the directory on the server, we need to store the verifier before
the RPC calls to LOOKUP

NFS: Fix up directory verifier races

In order to avoid having our dentry revalidation race with an update
of the directory on the server, we need to store the verifier before
the RPC calls to LOOKUP and READDIR.

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

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nfs: optimise readdir cache page invalidation

When the directory is large and it's being modified by one client
while another client is doing the 'ls -l' on the same directory then
the cache page in

nfs: optimise readdir cache page invalidation

When the directory is large and it's being modified by one client
while another client is doing the 'ls -l' on the same directory then
the cache page invalidation from nfs_force_use_readdirplus causes
the reading client to keep restarting READDIRPLUS from cookie 0
which causes the 'ls -l' to take a very long time to complete,
possibly never completing.

Currently when nfs_force_use_readdirplus is called to switch from
READDIR to READDIRPLUS, it invalidates all the cached pages of the
directory. This cache page invalidation causes the next nfs_readdir
to re-read the directory content from cookie 0.

This patch is to optimise the cache invalidation in
nfs_force_use_readdirplus by only truncating the cached pages from
last page index accessed to the end the file. It also marks the
inode to delay invalidating all the cached page of the directory
until the next initial nfs_readdir of the next 'ls' instance.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Trond Myklebust <trond.myklebust@hammerspace.com>
[Anna - Fix conflicts with Trond's readdir patches]
[Anna - Remove redundant call to nfs_zap_mapping()]
[Anna - Replace d_inode(file_dentry(desc->file)) with file_inode(desc->file)]
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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NFS: Switch readdir to using iterate_shared()

Now that the page cache locking is repaired, we should be able to
switch to using iterate_shared() for improved concurrency when
doing readdir().

Signe

NFS: Switch readdir to using iterate_shared()

Now that the page cache locking is repaired, we should be able to
switch to using iterate_shared() for improved concurrency when
doing readdir().

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

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NFS: Use kmemdup_nul() in nfs_readdir_make_qstr()

The directory strings stored in the readdir cache may be used with
printk(), so it is better to ensure they are nul-terminated.

Signed-off-by: Tron

NFS: Use kmemdup_nul() in nfs_readdir_make_qstr()

The directory strings stored in the readdir cache may be used with
printk(), so it is better to ensure they are nul-terminated.

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

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NFS: Directory page cache pages need to be locked when read

When a NFS directory page cache page is removed from the page cache,
its contents are freed through a call to nfs_readdir_clear_array().
T

NFS: Directory page cache pages need to be locked when read

When a NFS directory page cache page is removed from the page cache,
its contents are freed through a call to nfs_readdir_clear_array().
To prevent the removal of the page cache entry until after we've
finished reading it, we must take the page lock.

Fixes: 11de3b11e08c ("NFS: Fix a memory leak in nfs_readdir")
Cc: stable@vger.kernel.org # v2.6.37+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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NFS: Fix memory leaks and corruption in readdir

nfs_readdir_xdr_to_array() must not exit without having initialised
the array, so that the page cache deletion routines can safely
call nfs_readdir_cl

NFS: Fix memory leaks and corruption in readdir

nfs_readdir_xdr_to_array() must not exit without having initialised
the array, so that the page cache deletion routines can safely
call nfs_readdir_clear_array().
Furthermore, we should ensure that if we exit nfs_readdir_filler()
with an error, we free up any page contents to prevent a leak
if we try to fill the page again.

Fixes: 11de3b11e08c ("NFS: Fix a memory leak in nfs_readdir")
Cc: stable@vger.kernel.org # v2.6.37+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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NFS: nfs_access_get_cached_rcu() should use cred_fscmp()

We do not need to have the rcu lookup method fail in the case where
the fsuid/fsgid and supplemental groups match.

Signed-off-by: Trond Mykl

NFS: nfs_access_get_cached_rcu() should use cred_fscmp()

We do not need to have the rcu lookup method fail in the case where
the fsuid/fsgid and supplemental groups match.

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

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NFS: Add softreval behaviour to nfs_lookup_revalidate()

If the server is unavaliable, we want to allow the revalidating
lookup to time out, and to default to validating the cached dentry
if the 'sof

NFS: Add softreval behaviour to nfs_lookup_revalidate()

If the server is unavaliable, we want to allow the revalidating
lookup to time out, and to default to validating the cached dentry
if the 'softreval' mount option is set.

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

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NFS: Trust cached access if we've already revalidated the inode once

If we've already revalidated the inode once then don't distrust the
access cache unless the NFS_INO_INVALID_ACCESS flag is actual

NFS: Trust cached access if we've already revalidated the inode once

If we've already revalidated the inode once then don't distrust the
access cache unless the NFS_INO_INVALID_ACCESS flag is actually set.

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

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NFS: Improve tracing of permission calls

On exit from nfs_do_access(), record the mask representing the requested
permissions, as well as the server-supplied set of access rights for
this user.

Sig

NFS: Improve tracing of permission calls

On exit from nfs_do_access(), record the mask representing the requested
permissions, as well as the server-supplied set of access rights for
this user.

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

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NFS: remove unused check for negative dentry

This check has been hanging out since we used to have parallel paths to add
dentry in nfs_create(), but that hasn't been the case for some years.

Signed

NFS: remove unused check for negative dentry

This check has been hanging out since we used to have parallel paths to add
dentry in nfs_create(), but that hasn't been the case for some years.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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NFS: Refactor nfs_instantiate() for dentry referencing callers

Since commit b0c6108ecf64 ("nfs_instantiate(): prevent multiple aliases for
directory inode"), nfs_instantiate() may succeed without ac

NFS: Refactor nfs_instantiate() for dentry referencing callers

Since commit b0c6108ecf64 ("nfs_instantiate(): prevent multiple aliases for
directory inode"), nfs_instantiate() may succeed without actually
instantiating the dentry that was passed in. That can be problematic for
some callers in NFSv3, so this patch breaks things up so we can get the
actual dentry obtained.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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NFSv4: Fix return value in nfs_finish_open()

If the file turns out to be of the wrong type after opening, we want
to revalidate the path and retry, so return EOPENSTALE rather than
ESTALE.

Signed-o

NFSv4: Fix return value in nfs_finish_open()

If the file turns out to be of the wrong type after opening, we want
to revalidate the path and retry, so return EOPENSTALE rather than
ESTALE.

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

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Revert "NFS: readdirplus optimization by cache mechanism" (memleak)

This reverts commit be4c2d4723a4a637f0d1b4f7c66447141a4b3564.

That commit caused a severe memory leak in nfs_readdir_make_qstr().

Revert "NFS: readdirplus optimization by cache mechanism" (memleak)

This reverts commit be4c2d4723a4a637f0d1b4f7c66447141a4b3564.

That commit caused a severe memory leak in nfs_readdir_make_qstr().

When listing a directory with more than 100 files (this is how many
struct nfs_cache_array_entry elements fit in one 4kB page), all
allocated file name strings past those 100 leak.

The root of the leakage is that those string pointers are managed in
pages which are never linked into the page cache.

fs/nfs/dir.c puts pages into the page cache by calling
read_cache_page(); the callback function nfs_readdir_filler() will
then fill the given page struct which was passed to it, which is
already linked in the page cache (by do_read_cache_page() calling
add_to_page_cache_lru()).

Commit be4c2d4723a4 added another (local) array of allocated pages, to
be filled with more data, instead of discarding excess items received
from the NFS server. Those additional pages can be used by the next
nfs_readdir_filler() call (from within the same nfs_readdir() call).

The leak happens when some of those additional pages are never used
(copied to the page cache using copy_highpage()). The pages will be
freed by nfs_readdir_free_pages(), but their contents will not. The
commit did not invoke nfs_readdir_clear_array() (and doing so would
have been dangerous, because it did not track which of those pages
were already copied to the page cache, risking double free bugs).

How to reproduce the leak:

- Use a kernel with CONFIG_SLUB_DEBUG_ON.

- Create a directory on a NFS mount with more than 100 files with
names long enough to use the "kmalloc-32" slab (so we can easily
look up the allocation counts):

for i in `seq 110`; do touch ${i}_0123456789abcdef; done

- Drop all caches:

echo 3 >/proc/sys/vm/drop_caches

- Check the allocation counter:

grep nfs_readdir /sys/kernel/slab/kmalloc-32/alloc_calls
30564391 nfs_readdir_add_to_array+0x73/0xd0 age=534558/4791307/6540952 pid=370-1048386 cpus=0-47 nodes=0-1

- Request a directory listing and check the allocation counters again:

ls
[...]
grep nfs_readdir /sys/kernel/slab/kmalloc-32/alloc_calls
30564511 nfs_readdir_add_to_array+0x73/0xd0 age=207/4792999/6542663 pid=370-1048386 cpus=0-47 nodes=0-1

There are now 120 new allocations.

- Drop all caches and check the counters again:

echo 3 >/proc/sys/vm/drop_caches
grep nfs_readdir /sys/kernel/slab/kmalloc-32/alloc_calls
30564401 nfs_readdir_add_to_array+0x73/0xd0 age=735/4793524/6543176 pid=370-1048386 cpus=0-47 nodes=0-1

110 allocations are gone, but 10 have leaked and will never be freed.

Unhelpfully, those allocations are explicitly excluded from KMEMLEAK,
that's why my initial attempts with KMEMLEAK were not successful:

/*
* Avoid a kmemleak false positive. The pointer to the name is stored
* in a page cache page which kmemleak does not scan.
*/
kmemleak_not_leak(string->name);

It would be possible to solve this bug without reverting the whole
commit:

- keep track of which pages were not used, and call
nfs_readdir_clear_array() on them, or
- manually link those pages into the page cache

But for now I have decided to just revert the commit, because the real
fix would require complex considerations, risking more dangerous
(crash) bugs, which may seem unsuitable for the stable branches.

Signed-off-by: Max Kellermann <mk@cm4all.com>
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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NFS: Add deferred cache invalidation for close-to-open consistency violations

If the client detects that close-to-open cache consistency has been
violated, and that the file or directory has been ch

NFS: Add deferred cache invalidation for close-to-open consistency violations

If the client detects that close-to-open cache consistency has been
violated, and that the file or directory has been changed on the
server, then do a cache invalidation when we're done working with
the file.
The reason we don't do an immediate cache invalidation is that we
want to avoid performance problems due to false positives. Also,
note that we cannot guarantee cache consistency in this situation
even if we do invalidate the cache.

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

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treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was use

treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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nfs: pass the correct prototype to read_cache_page

Fix the callbacks NFS passes to read_cache_page to actually have the
proper type expected. Casting around function pointers can easily
hide typing

nfs: pass the correct prototype to read_cache_page

Fix the callbacks NFS passes to read_cache_page to actually have the
proper type expected. Casting around function pointers can easily
hide typing bugs, and defeats control flow protection.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

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NFS: Fix typo in comments of nfs_readdir_alloc_pages()

This fixes the typo in comments of nfs_readdir_alloc_pages().
Because nfs_readdir_large_page and nfs_readdir_free_pagearray had been
renamed.

NFS: Fix typo in comments of nfs_readdir_alloc_pages()

This fixes the typo in comments of nfs_readdir_alloc_pages().
Because nfs_readdir_large_page and nfs_readdir_free_pagearray had been
renamed.

Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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NFS: Remove redundant semicolon

This removes redundant semicolon for ending code.

Fixes: c7944ebb9ce9 ("NFSv4: Fix lookup revalidate of regular files")
Signed-off-by: Liguang Zhang <zhangliguang@li

NFS: Remove redundant semicolon

This removes redundant semicolon for ending code.

Fixes: c7944ebb9ce9 ("NFSv4: Fix lookup revalidate of regular files")
Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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NFS: readdirplus optimization by cache mechanism

When listing very large directories via NFS, clients may take a long
time to complete. There are about three factors involved:

First of all, ls and

NFS: readdirplus optimization by cache mechanism

When listing very large directories via NFS, clients may take a long
time to complete. There are about three factors involved:

First of all, ls and practically every other method of listing a
directory including python os.listdir and find rely on libc readdir().
However readdir() only reads 32K of directory entries at a time, which
means that if you have a lot of files in the same directory, it is going
to take an insanely long time to read all the directory entries.

Secondly, libc readdir() reads 32K of directory entries at a time, in
kernel space 32K buffer split into 8 pages. One NFS readdirplus rpc will
be called for one page, which introduces many readdirplus rpc calls.

Lastly, one NFS readdirplus rpc asks for 32K data (filled by nfs_dentry)
to fill one page (filled by dentry), we found that nearly one third of
data was wasted.

To solve above problems, pagecache mechanism was introduced. One NFS
readdirplus rpc will ask for a large data (more than 32k), the data can
fill more than one page, the cached pages can be used for next readdir
call. This can reduce many readdirplus rpc calls and improve readdirplus
performance.

TESTING:
When listing very large directories(include 300 thousand files) via NFS

time ls -l /nfs_mount | wc -l

without the patch:
300001
real 1m53.524s
user 0m2.314s
sys 0m2.599s

with the patch:
300001
real 0m23.487s
user 0m2.305s
sys 0m2.558s

Improved performance: 79.6%
readdirplus rpc calls decrease: 85%

Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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NFS: Fix up documentation warnings

Fix up some compiler warnings about function parameters, etc not being
correctly described or formatted.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspa

NFS: Fix up documentation warnings

Fix up some compiler warnings about function parameters, etc not being
correctly described or formatted.

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

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NFS: struct nfs_open_dir_context: convert rpc_cred pointer to cred.

Use the common 'struct cred' to pass credentials for readdir.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schum

NFS: struct nfs_open_dir_context: convert rpc_cred pointer to cred.

Use the common 'struct cred' to pass credentials for readdir.

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

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NFS: change access cache to use 'struct cred'.

Rather than keying the access cache with 'struct rpc_cred',
use 'struct cred'. Then use cred_fscmp() to compare
credentials rather than comparing the

NFS: change access cache to use 'struct cred'.

Rather than keying the access cache with 'struct rpc_cred',
use 'struct cred'. Then use cred_fscmp() to compare
credentials rather than comparing the raw pointer.

A benefit of this approach is that in the common case we avoid the
rpc_lookup_cred_nonblock() call which can be slow when the cred cache is large.
This also keeps many fewer items pinned in the rpc cred cache, so the
cred cache is less likely to get large.

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

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NFSv4: Fix lookup revalidate of regular files

If we're revalidating an existing dentry in order to open a file, we need
to ensure that we check the directory has not changed before we optimise
away

NFSv4: Fix lookup revalidate of regular files

If we're revalidating an existing dentry in order to open a file, we need
to ensure that we check the directory has not changed before we optimise
away the lookup.

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

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