The current code assumes that when a request in the request array
does have a tc, it also has a rc.

This is normally true, but not always : when using RDMA, req->rc
will temporarily be set to NULL after the request has been sent.
That is usually OK though, as when the reply arrives, req->rc will be
reassigned to a sane value before the request is recycled.

But there is a catch : if the request is flushed, the reply will never
arrive, and req->rc will be NULL, but not req->tc.

This patch fixes p9_tag_alloc to take this into account.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

For zero copy request, error will be encoded in the user space buffer.
So copy the error code correctly using copy_from_user. Here we use the
extra bytes we allocate for zero copy request. If total error details
are more than P9_ZC_HDR_SZ - 7 bytes, we return -EFAULT. The patch also
avoid a memory allocation in the error path.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Make the default 9p experience better by defaulting to virtio transport if present.
These days most of the users are using 9p in a virtualized setup
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

If we dont' specify a protocol version default to 9P2000.L. 9P2000.L
have better support for posix semantic and is where all the recent development
is happening.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

9p has thre strucrtures that can encode inode stat information.  Modify
all of those structures to contain kuid_t and kgid_t values.  Modify
he wire encoders and decoders of those structures to use 'u' and 'g' instead of
'd' in the format string where uids and gids are present.

This results in all kuid and kgid conversion to and from on the wire values
being performed by the same code in protocol.c where the client is known
at the time of the conversion.

Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@gmail.com>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Modify the p9_client_rpc format specifiers of every function that
directly transmits a uid or a gid from 'd' to 'u' or 'g' as
appropriate.

Modify those same functions to take kuid_t and kgid_t parameters
instead of uid_t and gid_t parameters.

Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@gmail.com>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

While working on a modified server I had the Linux clients crash
a few times. This lead me to find this:

Some error codes are directly extracted from the server replies.
A malformed server reply could contain an invalid error code, with a
very large value. If this value is then passed to ERR_PTR() it will
not be properly detected as an error code by IS_ERR() and as a result
the kernel will dereference an invalid pointer.

This patch tries to avoid this.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

A recent commit that removed unnecessary casts of pointers
to the same type uncovered a missing __force cast.

Add it.

Reported by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Adding casts of objects to the same type is unnecessary
and confusing for a human reader.

For example, this cast:

	int y;
	int *p = (int *)&y;

I used the coccinelle script below to find and remove these
unnecessary casts.  I manually removed the conversions this
script produces of casts with __force and __user.

@@
type T;
T *p;
@@

-	(T *)p
+	p
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use of "unsigned int" is preferred to bare "unsigned" in net tree.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a Tclunk or Tremove request is flushed, the fid is not freed on the
server.

p9_client_clunk() should retry once on interrupt, then if interrupted
again, leak the fid for the duration of the connection.

p9_client_remove() should call p9_client_clunk() on interrupt
instead of unconditionally destroying the fid.
Signed-off-by: NJim Garlick <garlick@llnl.gov>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

When a signal is received while sending a Tflush, the client,
which has recursed into p9_client_rpc() while sending another request,
should wait for Rflush as long as the transport is still up.
Signed-off-by: NJim Garlick <garlick@llnl.gov>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Reduce object size by deduplicating formats.

Use vsprintf extension %pV.
Rename P9_DPRINTK uses to p9_debug, align arguments.
Add function for _p9_debug and macro to add __func__.
Add missing "\n"s to p9_debug uses.
Remove embedded function names as p9_debug adds it.
Remove P9_EPRINTK macro and convert use to pr_<level>.
Add and use pr_fmt and pr_<level>.

$ size fs/9p/built-in.o*
   text	   data	    bss	    dec	    hex	filename
  62133	    984	  16000	  79117	  1350d	fs/9p/built-in.o.new
  67342	    984	  16928	  85254	  14d06	fs/9p/built-in.o.old
$ size net/9p/built-in.o*
   text	   data	    bss	    dec	    hex	filename
  88792	   4148	  22024	 114964	  1c114	net/9p/built-in.o.new
  94072	   4148	  23232	 121452	  1da6c	net/9p/built-in.o.old
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This helps in more control over debugging.
root@qemu-img-64:~# ls /pass/123
ls: cannot access /pass/123: No such file or directory
root@qemu-img-64:~# cat /sys/kernel/debug/tracing/trace
# tracer: nop
#
#           TASK-PID    CPU#    TIMESTAMP  FUNCTION
#              | |       |          |         |
              ls-1536  [001]    70.928584: 9p_protocol_dump: clnt 18446612132784021504 P9_TWALK(tag = 1)
000: 16 00 00 00 6e 01 00 01 00 00 00 02 00 00 00 01
010: 00 03 00 31 32 33 00 00 00 ff ff ff ff 00 00 00

              ls-1536  [001]    70.928587: <stack trace>
 => trace_9p_protocol_dump
 => p9pdu_finalize
 => p9_client_rpc
 => p9_client_walk
 => v9fs_vfs_lookup
 => d_alloc_and_lookup
 => walk_component
 => path_lookupat
              ls-1536  [000]    70.929696: 9p_protocol_dump: clnt 18446612132784021504 P9_RLERROR(tag = 1)
000: 0b 00 00 00 07 01 00 02 00 00 00 4e 03 00 02 00
010: 00 00 00 00 03 00 02 00 00 00 00 00 ff 43 00 00

              ls-1536  [000]    70.929697: <stack trace>
 => trace_9p_protocol_dump
 => p9_client_rpc
 => p9_client_walk
 => v9fs_vfs_lookup
 => d_alloc_and_lookup
 => walk_component
 => path_lookupat
 => do_path_lookup
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Without this msize=4294967295 will result in a crash
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Instead of saying all integer argument option should be listed in the beginning
move integer parsing to each option type.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

We dereferenced "req->tc" and "req->rc" before checking for NULL.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

* remove lot of update to different data structure
* add a seperate callback for zero copy request.
* above makes non zero copy code path simpler
* remove conditionalizing TREAD/TREADDIR/TWRITE in the zero copy path
* Fix the dotu p9_check_errors with zero copy. Add sufficient doc around
* Add support for both in and output buffers in zero copy callback
* pin and unpin pages in the same context
* use helpers instead of defining page offset and rest of page ourself
* Fix mem leak in p9_check_errors
* Remove 'E' and 'F' in p9pdu_vwritef
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

msize represents the maximum PDU size that includes P9_IOHDRSZ.

Signed-off-by: Venkateswararao Jujjuri "<jvrao@linux.vnet.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

unlinkat - Remove a directory entry

size[4] Tunlinkat tag[2] dirfid[4] name[s] flag[4]
size[4] Runlinkat tag[2]

older Tremove have the below request format

size[4] Tremove tag[2] fid[4]

The remove message is used to remove a directory entry either file or directory
The remove opreation is actually a directory opertation and should ideally have
dirfid, if not we cannot represent the fid on server with anything other than
name. We will have to derive the directory name from fid in the Tremove request.

NOTE: The operation doesn't clunk the unlink fid.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

renameat - change name of file or directory

size[4] Trenameat tag[2] olddirfid[4] oldname[s] newdirfid[4] newname[s]
size[4] Rrenameat tag[2]

older Trename have the below request format

size[4] Trename tag[2] fid[4] newdirfid[4] name[s]

The rename message is used to change the name of a file, possibly moving it
to a new directory. The rename opreation is actually a directory opertation
and should ideally have olddirfid, if not we cannot represent the fid on server
with anything other than name. We will have to derive the old directory name
from fid in the Trename request.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NPrem Karat <prem.karat@linux.vnet.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

free the fid even in case of failed clunk.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Switch to generic kernel hexdump library and cleanup macros to
be more consistent with the way we do normal debug prints.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

There was a BUG_ON to protect against a bad id which could be dealt with
more gracefully.
Reported-by: NNatalie Orlin <norlin@us.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

We need to return -1 on error. Also handle error properly
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Typo fixes and minor cleanups for v9fs
Signed-off-by: NRob Landley <rob@landley.net>
Reviewed-by: NVenkateswararao Jujjuri (JV) <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Use proper data type to handle get_user_pages_fast error condition. Also
do not treat EFAULT error as fatal.
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NHarsh Prateek Bora <harsh@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric VAn Hensbergen <ericvh@gmail.com>

Now that we use write_inode to flush server
cache related to fid, we don't need tsyncfs either fort dotl or dotu
protocols. For dotu this helps to do a more efficient server flush.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Fixes the following warnings:

net/9p/client.c:1305:18: warning: variable ‘total’ set but not used [-Wunused-but-set-variable]
net/9p/client.c:1370:18: warning: variable ‘total’ set but not used [-Wunused-but-set-variable]
net/9p/client.c:1769:18: warning: variable ‘total’ set but not used [-Wunused-but-set-variable]
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

Without this we can cause reclaim allocation in writepage.

[ 3433.448430] =================================
[ 3433.449117] [ INFO: inconsistent lock state ]
[ 3433.449117] 2.6.38-rc5+ #84
[ 3433.449117] ---------------------------------
[ 3433.449117] inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-R} usage.
[ 3433.449117] kswapd0/505 [HC0[0]:SC0[0]:HE1:SE1] takes:
[ 3433.449117]  (iprune_sem){+++++-}, at: [<ffffffff810ebbab>] shrink_icache_memory+0x45/0x2b1
[ 3433.449117] {RECLAIM_FS-ON-W} state was registered at:
[ 3433.449117]   [<ffffffff8107fe5f>] mark_held_locks+0x52/0x70
[ 3433.449117]   [<ffffffff8107ff02>] lockdep_trace_alloc+0x85/0x9f
[ 3433.449117]   [<ffffffff810d353d>] slab_pre_alloc_hook+0x18/0x3c
[ 3433.449117]   [<ffffffff810d3fd5>] kmem_cache_alloc+0x23/0xa2
[ 3433.449117]   [<ffffffff8127be77>] idr_pre_get+0x2d/0x6f
[ 3433.449117]   [<ffffffff815434eb>] p9_idpool_get+0x30/0xae
[ 3433.449117]   [<ffffffff81540123>] p9_client_rpc+0xd7/0x9b0
[ 3433.449117]   [<ffffffff815427b0>] p9_client_clunk+0x88/0xdb
[ 3433.449117]   [<ffffffff811d56e5>] v9fs_evict_inode+0x3c/0x48
[ 3433.449117]   [<ffffffff810eb511>] evict+0x1f/0x87
[ 3433.449117]   [<ffffffff810eb5c0>] dispose_list+0x47/0xe3
[ 3433.449117]   [<ffffffff810eb8da>] evict_inodes+0x138/0x14f
[ 3433.449117]   [<ffffffff810d90e2>] generic_shutdown_super+0x57/0xe8
[ 3433.449117]   [<ffffffff810d91e8>] kill_anon_super+0x11/0x50
[ 3433.449117]   [<ffffffff811d4951>] v9fs_kill_super+0x49/0xab
[ 3433.449117]   [<ffffffff810d926e>] deactivate_locked_super+0x21/0x46
[ 3433.449117]   [<ffffffff810d9e84>] deactivate_super+0x40/0x44
[ 3433.449117]   [<ffffffff810ef848>] mntput_no_expire+0x100/0x109
[ 3433.449117]   [<ffffffff810f0aeb>] sys_umount+0x2f1/0x31c
[ 3433.449117]   [<ffffffff8102c87b>] system_call_fastpath+0x16/0x1b
[ 3433.449117] irq event stamp: 192941
[ 3433.449117] hardirqs last  enabled at (192941): [<ffffffff81568dcf>] _raw_spin_unlock_irq+0x2b/0x30
[ 3433.449117] hardirqs last disabled at (192940): [<ffffffff810b5f97>] shrink_inactive_list+0x290/0x2f5
[ 3433.449117] softirqs last  enabled at (188470): [<ffffffff8105fd65>] __do_softirq+0x133/0x152
[ 3433.449117] softirqs last disabled at (188455): [<ffffffff8102d7cc>] call_softirq+0x1c/0x28
[ 3433.449117]
[ 3433.449117] other info that might help us debug this:
[ 3433.449117] 1 lock held by kswapd0/505:
[ 3433.449117]  #0:  (shrinker_rwsem){++++..}, at: [<ffffffff810b52e2>] shrink_slab+0x38/0x15f
[ 3433.449117]
[ 3433.449117] stack backtrace:
[ 3433.449117] Pid: 505, comm: kswapd0 Not tainted 2.6.38-rc5+ #84
[ 3433.449117] Call Trace:
[ 3433.449117]  [<ffffffff8107fbce>] ? valid_state+0x17e/0x191
[ 3433.449117]  [<ffffffff81036896>] ? save_stack_trace+0x28/0x45
[ 3433.449117]  [<ffffffff81080426>] ? check_usage_forwards+0x0/0x87
[ 3433.449117]  [<ffffffff8107fcf4>] ? mark_lock+0x113/0x22c
[ 3433.449117]  [<ffffffff8108105f>] ? __lock_acquire+0x37a/0xcf7
[ 3433.449117]  [<ffffffff8107fc0e>] ? mark_lock+0x2d/0x22c
[ 3433.449117]  [<ffffffff81081077>] ? __lock_acquire+0x392/0xcf7
[ 3433.449117]  [<ffffffff810b14d2>] ? determine_dirtyable_memory+0x15/0x28
[ 3433.449117]  [<ffffffff81081a33>] ? lock_acquire+0x57/0x6d
[ 3433.449117]  [<ffffffff810ebbab>] ? shrink_icache_memory+0x45/0x2b1
[ 3433.449117]  [<ffffffff81567d85>] ? down_read+0x47/0x5c
[ 3433.449117]  [<ffffffff810ebbab>] ? shrink_icache_memory+0x45/0x2b1
[ 3433.449117]  [<ffffffff810ebbab>] ? shrink_icache_memory+0x45/0x2b1
[ 3433.449117]  [<ffffffff810b5385>] ? shrink_slab+0xdb/0x15f
[ 3433.449117]  [<ffffffff810b69bc>] ? kswapd+0x574/0x96a
[ 3433.449117]  [<ffffffff810b6448>] ? kswapd+0x0/0x96a
[ 3433.449117]  [<ffffffff810714e2>] ? kthread+0x7d/0x85
[ 3433.449117]  [<ffffffff8102d6d4>] ? kernel_thread_helper+0x4/0x10
[ 3433.449117]  [<ffffffff81569200>] ? restore_args+0x0/0x30
[ 3433.449117]  [<ffffffff81071465>] ? kthread+0x0/0x85
[ 3433.449117]  [<ffffffff8102d6d0>] ? kernel_thread_helper+0x0/0x10
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

If a transport prefers payload to be sent separate from the PDU
(P9_TRANS_PREF_PAYLOAD_SEP), there is no need to allocate msize
PDU buffers(struct p9_fcall).

This patch allocates only upto 4k buffers for this kind of transports
and there won't be any change to the legacy transports.

Hence, this patch on top of zero copy changes allows user to
specify higher msizes through the mount option
without hogging the kernel heap.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This takes care of copying out error buffers from user buffer
payloads when we are using zero copy.  This happens because the
only payload buffer the server has to respond to the request is
the user buffer given for the zero copy read.

Because we only use zerocopy when the amount of data to transfer
is greater than a certain size (currently 4K) and error strings are
limited to ERRMAX (currently 128) we don't need to worry about there
being sufficient space for the error to fit in the payload.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Modify p9_client_readdir() to check the transport preference and act according
If the preference is P9_TRANS_PREF_PAYLOAD_SEP, send the payload
separately instead of putting it directly on PDU.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Modify p9_client_write() to check the transport preference and act accordingly.
If the preference is P9_TRANS_PREF_PAYLOAD_SEP, send the payload
separately instead of putting it directly on PDU.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Modify p9_client_read() to check the transport preference and act accordingly.
If the preference is P9_TRANS_PREF_PAYLOAD_SEP, send the payload
separately instead of putting it directly on PDU.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This patch ensures that a read(fd, NULL, 10) returns  EFAULT on a 9p file.
Signed-off-by: NSanchit Garg <sancgarg@linux.vnet.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>