netfs, 9p: Implement helpers for new write code

Implement the helpers for the new write code in 9p. There's now an
optional ->prepare_write() that allows the filesystem to set the parameters
for th

netfs, 9p: Implement helpers for new write code

Implement the helpers for the new write code in 9p. There's now an
optional ->prepare_write() that allows the filesystem to set the parameters
for the next write, such as maximum size and maximum segment count, and an
->issue_write() that is called to initiate an (asynchronous) write
operation.

Signed-off-by: David Howells <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
cc: Eric Van Hensbergen <[email protected]>
cc: Latchesar Ionkov <[email protected]>
cc: Dominique Martinet <[email protected]>
cc: Christian Schoenebeck <[email protected]>
cc: [email protected]
cc: [email protected]
cc: [email protected]

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9p: Add client parameter to p9_req_put()

This is to aid in adding mempools, in the next patch.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kent

9p: Add client parameter to p9_req_put()

This is to aid in adding mempools, in the next patch.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kent Overstreet <[email protected]>
Cc: Eric Van Hensbergen <[email protected]>
Cc: Latchesar Ionkov <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>

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9p: Drop kref usage

An upcoming patch is going to require passing the client through
p9_req_put() -> p9_req_free(), but that's awkward with the kref
indirection - so this patch switches to using ref

9p: Drop kref usage

An upcoming patch is going to require passing the client through
p9_req_put() -> p9_req_free(), but that's awkward with the kref
indirection - so this patch switches to using refcount_t directly.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kent Overstreet <[email protected]>
Cc: Eric Van Hensbergen <[email protected]>
Cc: Latchesar Ionkov <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>

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9p fid refcount: add a 9p_fid_ref tracepoint

This adds a tracepoint event for 9p fid lifecycle tracing: when a fid
is created, its reference count increased/decreased, and freed.
The new 9p_fid_ref

9p fid refcount: add a 9p_fid_ref tracepoint

This adds a tracepoint event for 9p fid lifecycle tracing: when a fid
is created, its reference count increased/decreased, and freed.
The new 9p_fid_ref tracepoint should help anyone wishing to debug any
fid problem such as missing clunk (destroy) or use-after-free.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Dominique Martinet <[email protected]>

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9p fid refcount: add p9_fid_get/put wrappers

I was recently reminded that it is not clear that p9_client_clunk()
was actually just decrementing refcount and clunking only when that
reaches zero: mak

9p fid refcount: add p9_fid_get/put wrappers

I was recently reminded that it is not clear that p9_client_clunk()
was actually just decrementing refcount and clunking only when that
reaches zero: make it clear through a set of helpers.

This will also allow instrumenting refcounting better for debugging
next patch

Link: https://lkml.kernel.org/r/[email protected]
Reviewed-by: Tyler Hicks <[email protected]>
Reviewed-by: Christian Schoenebeck <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>

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9p: fix a bunch of checkpatch warnings

Sohaib Mohamed started a serie of tiny and incomplete checkpatch fixes but
seemingly stopped halfway -- take over and do most of it.
This is still missing net/

9p: fix a bunch of checkpatch warnings

Sohaib Mohamed started a serie of tiny and incomplete checkpatch fixes but
seemingly stopped halfway -- take over and do most of it.
This is still missing net/9p/trans* and net/9p/protocol.c for a later
time...

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Dominique Martinet <[email protected]>

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9p: fix file headers

- add missing SPDX-License-Identifier
- remove (sometimes incorrect) file name from file header

Link: http://lkml.kernel.org/r/20211102134608.1588018-2-dominique.martinet@atmar

9p: fix file headers

- add missing SPDX-License-Identifier
- remove (sometimes incorrect) file name from file header

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Dominique Martinet <[email protected]>

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9p: apply review requests for fid refcounting

Fix style issues in parent commit ("apply review requests for fid
refcounting"), no functional change.

Link: http://lkml.kernel.org/r/1605802012-31133-

9p: apply review requests for fid refcounting

Fix style issues in parent commit ("apply review requests for fid
refcounting"), no functional change.

Link: http://lkml.kernel.org/r/[email protected]
Fixes: 6636b6dcc3db ("9p: add refcount to p9_fid struct")
Signed-off-by: Dominique Martinet <[email protected]>

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9p: add refcount to p9_fid struct

Fix race issue in fid contention.

Eric's and Greg's patch offer a mechanism to fix open-unlink-f*syscall
bug in 9p. But there is race issue in fid parallel accesse

9p: add refcount to p9_fid struct

Fix race issue in fid contention.

Eric's and Greg's patch offer a mechanism to fix open-unlink-f*syscall
bug in 9p. But there is race issue in fid parallel accesses.
As Greg's patch stores all of fids from opened files into according inode,
so all the lookup fid ops can retrieve fid from inode preferentially. But
there is no mechanism to handle the fid contention issue. For example,
there are two threads get the same fid in the same time and one of them
clunk the fid before the other thread ready to discard the fid. In this
scenario, it will lead to some fatal problems, even kernel core dump.

I introduce a mechanism to fix this race issue. A counter field introduced
into p9_fid struct to store the reference counter to the fid. When a fid
is allocated from the inode or dentry, the counter will increase, and
will decrease at the end of its occupation. It is guaranteed that the
fid won't be clunked before the reference counter go down to 0, then
we can avoid the clunked fid to be used.

tests:
race issue test from the old test case:
for file in {01..50}; do touch f.${file}; done
seq 1 1000 | xargs -n 1 -P 50 -I{} cat f.* > /dev/null

open-unlink-f*syscall test:
I have tested for f*syscall include: ftruncate fstat fchown fchmod faccessat.

Link: http://lkml.kernel.org/r/[email protected]
Fixes: 478ba09edc1f ("fs/9p: search open fids first")
Signed-off-by: Jianyong Wu <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>

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fs/9p: track open fids

This patch adds accounting of open fids in a list hanging off the i_private
field of the corresponding inode. This allows faster lookups compared to
searching the full 9p clie

fs/9p: track open fids

This patch adds accounting of open fids in a list hanging off the i_private
field of the corresponding inode. This allows faster lookups compared to
searching the full 9p client list.

The lookup code is modified accordingly.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kurz <[email protected]>
Signed-off-by: Jianyong Wu <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>

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net/9p: remove unused p9_req_t aux field

The p9_req_t field 'aux' has not been used in a very long time,
remove leftover field declaration

Link: http://lkml.kernel.org/r/1580941152-12973-1-git-send

net/9p: remove unused p9_req_t aux field

The p9_req_t field 'aux' has not been used in a very long time,
remove leftover field declaration

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Dominique Martinet <[email protected]>

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9pnet: allow making incomplete read requests

A user doesn't necessarily want to wait for all the requested data to
be available, since the waiting time for each request is unbounded.

The new method

9pnet: allow making incomplete read requests

A user doesn't necessarily want to wait for all the requested data to
be available, since the waiting time for each request is unbounded.

The new method permits sending one read request at a time and getting
the response ASAP, allowing to use 9pnet with synthetic file systems
representing arbitrary data streams.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Sergey Alirzaev <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 188

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 188

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not write to free software
foundation 51 franklin street fifth floor boston ma 02111 1301 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 27 file(s).

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Richard Fontana <[email protected]>
Reviewed-by: Alexios Zavras <[email protected]>
Reviewed-by: Steve Winslow <[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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9p: Add refcount to p9_req_t

To avoid use-after-free(s), use a refcount to keep track of the
usable references to any instantiated struct p9_req_t.

This commit adds p9_req_put(), p9_req_get() and p

9p: Add refcount to p9_req_t

To avoid use-after-free(s), use a refcount to keep track of the
usable references to any instantiated struct p9_req_t.

This commit adds p9_req_put(), p9_req_get() and p9_req_try_get() as
wrappers to kref_put(), kref_get() and kref_get_unless_zero().
These are used by the client and the transports to keep track of
valid requests' references.

p9_free_req() is added back and used as callback by kref_put().

Add SLAB_TYPESAFE_BY_RCU as it ensures that the memory freed by
kmem_cache_free() will not be reused for another type until the rcu
synchronisation period is over, so an address gotten under rcu read
lock is safe to inc_ref() without corrupting random memory while
the lock is held.

Link: http://lkml.kernel.org/r/[email protected]
Co-developed-by: Dominique Martinet <[email protected]>
Signed-off-by: Tomas Bortoli <[email protected]>
Reported-by: [email protected]
Signed-off-by: Dominique Martinet <[email protected]>

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9p: add a per-client fcall kmem_cache

Having a specific cache for the fcall allocations helps speed up
end-to-end latency.

The caches will automatically be merged if there are multiple caches
of it

9p: add a per-client fcall kmem_cache

Having a specific cache for the fcall allocations helps speed up
end-to-end latency.

The caches will automatically be merged if there are multiple caches
of items with the same size so we do not need to try to share a cache
between different clients of the same size.

Since the msize is negotiated with the server, only allocate the cache
after that negotiation has happened - previous allocations or
allocations of different sizes (e.g. zero-copy fcall) are made with
kmalloc directly.

Some figures on two beefy VMs with Connect-IB (sriov) / trans=rdma,
with ior running 32 processes in parallel doing small 32 bytes IOs:
- no alloc (4.18-rc7 request cache): 65.4k req/s
- non-power of two alloc, no patch: 61.6k req/s
- power of two alloc, no patch: 62.2k req/s
- non-power of two alloc, with patch: 64.7k req/s
- power of two alloc, with patch: 65.1k req/s

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Dominique Martinet <[email protected]>
Acked-by: Jun Piao <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Greg Kurz <[email protected]>

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9p: embed fcall in req to round down buffer allocs

'msize' is often a power of two, or at least page-aligned, so avoiding
an overhead of two dozen bytes for each allocation will help the
allocator d

9p: embed fcall in req to round down buffer allocs

'msize' is often a power of two, or at least page-aligned, so avoiding
an overhead of two dozen bytes for each allocation will help the
allocator do its work and reduce memory fragmentation.

Link: http://lkml.kernel.org/r/[email protected]
Suggested-by: Matthew Wilcox <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>
Reviewed-by: Greg Kurz <[email protected]>
Acked-by: Jun Piao <[email protected]>
Cc: Matthew Wilcox <[email protected]>

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9p: Use a slab for allocating requests

Replace the custom batch allocation with a slab. Use an IDR to store
pointers to the active requests instead of an array. We don't try to
handle P9_NOTAG spe

9p: Use a slab for allocating requests

Replace the custom batch allocation with a slab. Use an IDR to store
pointers to the active requests instead of an array. We don't try to
handle P9_NOTAG specially; the IDR will happily shrink all the way back
once the TVERSION call has completed.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox <[email protected]>
Cc: Eric Van Hensbergen <[email protected]>
Cc: Ron Minnich <[email protected]>
Cc: Latchesar Ionkov <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>

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9p: Embed wait_queue_head into p9_req_t

On a 64-bit system, the wait_queue_head_t is 24 bytes while the pointer
to it is 8 bytes. Growing the p9_req_t by 16 bytes is better than
performing a 24-byt

9p: Embed wait_queue_head into p9_req_t

On a 64-bit system, the wait_queue_head_t is 24 bytes while the pointer
to it is 8 bytes. Growing the p9_req_t by 16 bytes is better than
performing a 24-byte memory allocation.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox <[email protected]>
Reviewed-by: Greg Kurz <[email protected]>
Cc: Eric Van Hensbergen <[email protected]>
Cc: Ron Minnich <[email protected]>
Cc: Latchesar Ionkov <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>

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9p: Replace the fidlist with an IDR

The p9_idpool being used to allocate the IDs uses an IDR to allocate
the IDs ... which we then keep in a doubly-linked list, rather than in
the IDR which allocate

9p: Replace the fidlist with an IDR

The p9_idpool being used to allocate the IDs uses an IDR to allocate
the IDs ... which we then keep in a doubly-linked list, rather than in
the IDR which allocated them. We can use an IDR directly which saves
two pointers per p9_fid, and a tiny memory allocation per p9_client.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox <[email protected]>
Cc: Eric Van Hensbergen <[email protected]>
Cc: Ron Minnich <[email protected]>
Cc: Latchesar Ionkov <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>

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9p: Implement show_options

Implement the show_options superblock op for 9p as part of a bid to get
rid of s_options and generic_show_options() to make it easier to implement
a context-based mount wh

9p: Implement show_options

Implement the show_options superblock op for 9p as part of a bid to get
rid of s_options and generic_show_options() to make it easier to implement
a context-based mount where the mount options can be passed individually
over a file descriptor.

Signed-off-by: David Howells <[email protected]>
cc: Eric Van Hensbergen <[email protected]>
cc: Ron Minnich <[email protected]>
cc: Latchesar Ionkov <[email protected]>
cc: [email protected]
Signed-off-by: Al Viro <[email protected]>

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9p: constify ->d_name handling

Signed-off-by: Al Viro <[email protected]>

9p: switch p9_client_read() to passing struct iov_iter *

... and make it loop

Signed-off-by: Al Viro <[email protected]>

9p: switch p9_client_write() to passing it struct iov_iter *

... and make it loop until it's done

Signed-off-by: Al Viro <[email protected]>

9pnet: p9_client->conn field is unused. Remove it.

Signed-off-by: Simon Derr <[email protected]>
Signed-off-by: Eric Van Hensbergen <[email protected]>

9P: Get rid of REQ_STATUS_FLSH

This request state is mostly useless, and properly implementing it
for RDMA would require an extra lock to be taken in handle_recv()
and in rdma_cancel() to avoid this

9P: Get rid of REQ_STATUS_FLSH

This request state is mostly useless, and properly implementing it
for RDMA would require an extra lock to be taken in handle_recv()
and in rdma_cancel() to avoid this race:

handle_recv() rdma_cancel()
. .
. if req->state == SENT
req->state = RCVD .
. req->state = FLSH

So just get rid of it.

Signed-off-by: Simon Derr <[email protected]>
Signed-off-by: Eric Van Hensbergen <[email protected]>

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