SUNRPC: introduce cache_check_rcu to help check in rcu context

This is a prepare patch to add cache_check_rcu, will use it with follow
patch.

Suggested-by: NeilBrown <[email protected]>
Signed-off-by:

SUNRPC: introduce cache_check_rcu to help check in rcu context

This is a prepare patch to add cache_check_rcu, will use it with follow
patch.

Suggested-by: NeilBrown <[email protected]>
Signed-off-by: Yang Erkun <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>

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SUNRPC: change cache_head.flags bits to enum

When a sequence of numbers are needed for internal-use only, an enum is
typically best. The sequence will inevitably need to be changed one
day, and hav

SUNRPC: change cache_head.flags bits to enum

When a sequence of numbers are needed for internal-use only, an enum is
typically best. The sequence will inevitably need to be changed one
day, and having an enum means the developer doesn't need to think about
renumbering after insertion or deletion. Such patches will be easier
to review.

Signed-off-by: NeilBrown <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>

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SUNRPC: return proper error from get_expiry()

The get_expiry() function currently returns a timestamp, and uses the
special return value of 0 to indicate an error.

Unfortunately this causes a probl

SUNRPC: return proper error from get_expiry()

The get_expiry() function currently returns a timestamp, and uses the
special return value of 0 to indicate an error.

Unfortunately this causes a problem when 0 is the correct return value.

On a system with no RTC it is possible that the boot time will be seen
to be "3". When exportfs probes to see if a particular filesystem
supports NFS export it tries to cache information with an expiry time of
"3". The intention is for this to be "long in the past". Even with no
RTC it will not be far in the future (at most a second or two) so this
is harmless.
But if the boot time happens to have been calculated to be "3", then
get_expiry will fail incorrectly as it converts the number to "seconds
since bootime" - 0.

To avoid this problem we change get_expiry() to report the error quite
separately from the expiry time. The error is now the return value.
The expiry time is reported through a by-reference parameter.

Reported-by: Jerry Zhang <[email protected]>
Tested-by: Jerry Zhang <[email protected]>
Signed-off-by: NeilBrown <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>

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SUNRPC: Make cache_req::thread_wait an unsigned long

The second parameter of wait_for_completion_interruptible_timeout()
is a jiffies value whose type is "unsigned long". Avoid an
unnecessary and po

SUNRPC: Make cache_req::thread_wait an unsigned long

The second parameter of wait_for_completion_interruptible_timeout()
is a jiffies value whose type is "unsigned long". Avoid an
unnecessary and potentially fraught implicit type conversion at the
wait_for_completion_interruptible_timeout() call site in
cache_wait_req().

Signed-off-by: Chuck Lever <[email protected]>

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kernel.h: split out kstrtox() and simple_strtox() to a separate header

kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitti

kernel.h: split out kstrtox() and simple_strtox() to a separate header

kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out kstrtox() and
simple_strtox() helpers.

At the same time convert users in header and lib folders to use new
header. Though for time being include new header back to kernel.h to
avoid twisted indirected includes for existing users.

[[email protected]: fix documentation references]
Link: https://lkml.kernel.org/r/[email protected]

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Andy Shevchenko <[email protected]>
Acked-by: Jonathan Cameron <[email protected]>
Cc: Francis Laniel <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Kars Mulder <[email protected]>
Cc: Trond Myklebust <[email protected]>
Cc: Anna Schumaker <[email protected]>
Cc: "J. Bruce Fields" <[email protected]>
Cc: Chuck Lever <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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sunrpc: fix duplicated word in <linux/sunrpc/cache.h>

Change "time time" to "time expiry_time" to match the field name.

Signed-off-by: Randy Dunlap <[email protected]>
Cc: "J. Bruce Fields" <bf

sunrpc: fix duplicated word in <linux/sunrpc/cache.h>

Change "time time" to "time expiry_time" to match the field name.

Signed-off-by: Randy Dunlap <[email protected]>
Cc: "J. Bruce Fields" <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: Trond Myklebust <[email protected]>
Cc: Anna Schumaker <[email protected]>
Cc: [email protected]
Signed-off-by: Anna Schumaker <[email protected]>

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SUNRPC/cache: don't allow invalid entries to be flushed

Trond points out in commit 277f27e2f277 ("SUNRPC/cache: Allow
garbage collection of invalid cache entries") that we allow invalid
cache entrie

SUNRPC/cache: don't allow invalid entries to be flushed

Trond points out in commit 277f27e2f277 ("SUNRPC/cache: Allow
garbage collection of invalid cache entries") that we allow invalid
cache entries to persist indefinitely. That fix, however,
reintroduces the problem fixed by Kinglong Mee's commit d6fc8821c2d2
("SUNRPC/Cache: Always treat the invalid cache as unexpired"), where
an invalid cache entry is immediately removed by a flush before
mountd responds to it. The result is that the server thread that
should be waiting for mountd to fill in that entry instead gets an
-ETIMEDOUT return from cache_check(). Symptoms are the server
becoming unresponsive after a restart, reproduceable by running
pynfs 4.1 test REBT5.

Instead, take a compromise approach: allow invalid cache entries to
be removed after they expire, but not to be removed by a cache
flush.

Fixes: 277f27e2f277 ("SUNRPC/cache: Allow garbage collection ... ")
Signed-off-by: J. Bruce Fields <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>

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SUNRPC/cache: Allow garbage collection of invalid cache entries

If the cache entry never gets initialised, we want the garbage
collector to be able to evict it. Otherwise if the upcall daemon
fails

SUNRPC/cache: Allow garbage collection of invalid cache entries

If the cache entry never gets initialised, we want the garbage
collector to be able to evict it. Otherwise if the upcall daemon
fails to initialise the entry, we end up never expiring it.

Signed-off-by: Trond Myklebust <[email protected]>
[ cel: resolved a merge conflict ]
Signed-off-by: Chuck Lever <[email protected]>

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nfsd: export upcalls must not return ESTALE when mountd is down

If the rpc.mountd daemon goes down, then that should not cause all
exports to start failing with ESTALE errors. Let's explicitly
disti

nfsd: export upcalls must not return ESTALE when mountd is down

If the rpc.mountd daemon goes down, then that should not cause all
exports to start failing with ESTALE errors. Let's explicitly
distinguish between the cache upcall cases that need to time out,
and those that do not.

Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>

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nfs: use time64_t internally

The timestamps for the cache are all in boottime seconds, so they
don't overflow 32-bit values, but the use of time_t is deprecated
because it generally does overflow wh

nfs: use time64_t internally

The timestamps for the cache are all in boottime seconds, so they
don't overflow 32-bit values, but the use of time_t is deprecated
because it generally does overflow when used with wall-clock time.

There are multiple possible ways of avoiding it:

- leave time_t, which is safe here, but forces others to
look into this code to determine that it is over and over.

- use a more generic type, like 'int' or 'long', which is known
to be sufficient here but loses the documentation of referring
to timestamps

- use ktime_t everywhere, and convert into seconds in the few
places where we want realtime-seconds. The conversion is
sometimes expensive, but not more so than the conversion we
do today.

- use time64_t to clarify that this code is safe. Nothing would
change for 64-bit architectures, but it is slightly less
efficient on 32-bit architectures.

Without a clear winner of the three approaches above, this picks
the last one, favouring readability over a small performance
loss on 32-bit architectures.

Signed-off-by: Arnd Bergmann <[email protected]>

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sunrpc: add a new cache_detail operation for when a cache is flushed

When the exports table is changed, exportfs will usually write a new
time to the "flush" file in the nfsd.export cache procfile.

sunrpc: add a new cache_detail operation for when a cache is flushed

When the exports table is changed, exportfs will usually write a new
time to the "flush" file in the nfsd.export cache procfile. This tells
the kernel to flush any entries that are older than that value.

This gives us a mechanism to tell whether an unexport might have
occurred. Add a new ->flush cache_detail operation that is called after
flushing the cache whenever someone writes to a "flush" file.

Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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SUNRPC: Track writers of the 'channel' file to improve cache_listeners_exist

The sunrpc cache interface is susceptible to being fooled by a rogue
process just reading a 'channel' file. If this happ

SUNRPC: Track writers of the 'channel' file to improve cache_listeners_exist

The sunrpc cache interface is susceptible to being fooled by a rogue
process just reading a 'channel' file. If this happens the kernel
may think a valid daemon exists to service the cache when it does not.
For example, the following may fool the kernel:
cat /proc/net/rpc/auth.unix.gid/channel

Change the tracking of readers to writers when considering whether a
listener exists as all valid daemon processes either open a channel
file O_RDWR or O_WRONLY. While this does not prevent a rogue process
from "stealing" a message from the kernel, it does at least improve
the kernels perception of whether a valid process servicing the cache
exists.

Signed-off-by: Dave Wysochanski <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 363

Based on 1 normalized pattern(s):

released under terms in gpl version 2 see copying

extracted by the scancode license scanner t

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 363

Based on 1 normalized pattern(s):

released under terms in gpl version 2 see copying

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 5 file(s).

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Armijn Hemel <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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SUNRPC: Replace the cache_detail->hash_lock with a regular spinlock

Now that the reader functions are all RCU protected, use a regular
spinlock rather than a reader/writer lock.

Signed-off-by: Tron

SUNRPC: Replace the cache_detail->hash_lock with a regular spinlock

Now that the reader functions are all RCU protected, use a regular
spinlock rather than a reader/writer lock.

Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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SUNRPC: Remove non-RCU protected lookup

Clean up the cache code by removing the non-RCU protected lookup.

Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: J. Bruce Fi

SUNRPC: Remove non-RCU protected lookup

Clean up the cache code by removing the non-RCU protected lookup.

Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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SUNRPC: Allow cache lookups to use RCU protection rather than the r/w spinlock

Instead of the reader/writer spinlock, allow cache lookups to use RCU
for looking up entries. This is more efficient si

SUNRPC: Allow cache lookups to use RCU protection rather than the r/w spinlock

Instead of the reader/writer spinlock, allow cache lookups to use RCU
for looking up entries. This is more efficient since modifications can
occur while other entries are being looked up.

Note that for now, we keep the reader/writer spinlock until all users
have been converted to use RCU-safe freeing of their cache entries.

Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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sunrpc: make the function arg as const

Make the struct cache_detail *tmpl argument of the function
cache_create_net as const as it is only getting passed to kmemup having
the argument as const void

sunrpc: make the function arg as const

Make the struct cache_detail *tmpl argument of the function
cache_create_net as const as it is only getting passed to kmemup having
the argument as const void *.
Add const to the prototype too.

Signed-off-by: Bhumika Goyal <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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sunrpc/nfs: cleanup procfs/pipefs entry in cache_detail

Record flush/channel/content entries is useless, remove them.

Signed-off-by: Kinglong Mee <[email protected]>
Signed-off-by: Anna Schumak

sunrpc/nfs: cleanup procfs/pipefs entry in cache_detail

Record flush/channel/content entries is useless, remove them.

Signed-off-by: Kinglong Mee <[email protected]>
Signed-off-by: Anna Schumaker <[email protected]>

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SUNRPC/Cache: Always treat the invalid cache as unexpired

When the first time pynfs runs after rpc/nfsd startup, always get the warning,

"Got error: Connection closed"

I found the problem is cause

SUNRPC/Cache: Always treat the invalid cache as unexpired

When the first time pynfs runs after rpc/nfsd startup, always get the warning,

"Got error: Connection closed"

I found the problem is caused by,
1. A new startup of nfsd, rpc.mountd, etc,
2. A rpc request from client (pynfs test, or normal mounting),
3. An ip_map cache is created but invalid, so upcall to rpc.mountd,
4. rpc.mountd process the ip_map upcall, before write the valid data to nfsd,
do auth_reload(), and check_useipaddr(),
5. For the first time, old_use_ipaddr = -1, it causes rpc.mountd do write_flush that doing cache_clean,
6. The ip_map cache will be treat as expired and clean,
7. When rpc.mountd write the valid data to nfsd, a new ip_map is created
and updated, the cache_check of old ip_map(doing the upcall) will
return -ETIMEDOUT.
8. RPC layer return SVC_CLOSE and close the xprt after commit 4d712ef1db05
"svcauth_gss: Close connection when dropping an incoming message"

NeilBrown suggest in another email,

"If CACHE_VALID is not set, then there is no data in the cache item,
so there is nothing to expire. So it would be nice if cache items that
don't have CACHE_VALID are never treated as expired."

v3, change the order of the two patches
v2, change the checking of CACHE_PENDING to CACHE_VALID

Reviewed-by: NeilBrown <[email protected]>
Signed-off-by: Kinglong Mee <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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svcrpc: free contexts immediately on PROC_DESTROY

We currently handle a client PROC_DESTROY request by turning it
CACHE_NEGATIVE, setting the expired time to now, and then waiting for
cache_clean to

svcrpc: free contexts immediately on PROC_DESTROY

We currently handle a client PROC_DESTROY request by turning it
CACHE_NEGATIVE, setting the expired time to now, and then waiting for
cache_clean to clean it up later. Since we forgot to set the cache's
nextcheck value, that could take up to 30 minutes. Also, though there's
probably no real bug in this case, setting CACHE_NEGATIVE directly like
this probably isn't a great idea in general.

So let's just remove the entry from the cache directly, and move this
bit of cache manipulation to a helper function.

Signed-off-by: Neil Brown <[email protected]>
Reported-by: Andy Adamson <[email protected]>
Signed-off-by: Andy Adamson <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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locking/atomic, kref: Add kref_read()

Since we need to change the implementation, stop exposing internals.

Provide kref_read() to read the current reference count; typically
used for debug messages

locking/atomic, kref: Add kref_read()

Since we need to change the implementation, stop exposing internals.

Provide kref_read() to read the current reference count; typically
used for debug messages.

Kills two anti-patterns:

atomic_read(&kref->refcount)
kref->refcount.counter

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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sunrpc: remove 'inuse' flag from struct cache_detail.

This field is not currently in use.

Signed-off-by: NeilBrown <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

sunrpc/cache: make cache flushing more reliable.

The caches used to store sunrpc authentication information can be
flushed by writing a timestamp to a file in /proc.

This timestamp has a one-second

sunrpc/cache: make cache flushing more reliable.

The caches used to store sunrpc authentication information can be
flushed by writing a timestamp to a file in /proc.

This timestamp has a one-second resolution and any entry in cache that
was last_refreshed *before* that time is treated as expired.

This is problematic as it is not possible to reliably flush the cache
without interrupting NFS service.
If the current time is written to the "flush" file, any entry that was
added since the current second started will still be treated as valid.
If one second beyond than the current time is written to the file
then no entries can be valid until the second ticks over. This will
mean that no NFS request will be handled for up to 1 second.

To resolve this issue we make two changes:

1/ treat an entry as expired if the timestamp when it was last_refreshed
is before *or the same as* the expiry time. This means that current
code which writes out the current time will now flush the cache
reliably.

2/ when a new entry in added to the cache - set the last_refresh timestamp
to 1 second *beyond* the current flush time, when that not in the
past.
This ensures that newly added entries will always be valid.

Now that we have a very reliable way to flush the cache, and also
since we are using "since-boot" timestamps which are monotonic,
change cache_purge() to set the smallest future flush_time which
will work, and leave it there: don't revert to '1'.

Also disable the setting of the 'flush_time' far into the future.
That has never been useful and is now awkward as it would cause
last_refresh times to be strange.
Finally: if a request is made to set the 'flush_time' to the current
second, assume the intent is to flush the cache and advance it, if
necessary, to 1 second beyond the current 'flush_time' so that all
active entries will be deemed to be expired.

As part of this we need to add a 'cache_detail' arg to cache_init()
and cache_fresh_locked() so they can find the current ->flush_time.

Signed-off-by: NeilBrown <[email protected]>
Reported-by: Olaf Kirch <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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sunrpc: Switch to using hash list instead single list

Switch using list_head for cache_head in cache_detail,
it is useful of remove an cache_head entry directly from cache_detail.

v8, using hash li

sunrpc: Switch to using hash list instead single list

Switch using list_head for cache_head in cache_detail,
it is useful of remove an cache_head entry directly from cache_detail.

v8, using hash list, not head list

Signed-off-by: Kinglong Mee <[email protected]>
Reviewed-by: NeilBrown <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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sunrpc/nfsd: Remove redundant code by exports seq_operations functions

Nfsd has implement a site of seq_operations functions as sunrpc's cache.
Just exports sunrpc's codes, and remove nfsd's redunda

sunrpc/nfsd: Remove redundant code by exports seq_operations functions

Nfsd has implement a site of seq_operations functions as sunrpc's cache.
Just exports sunrpc's codes, and remove nfsd's redundant codes.

v8, same as v6

Signed-off-by: Kinglong Mee <[email protected]>
Reviewed-by: NeilBrown <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

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