This patch applies on top of 9P2000.L patches that we have on the list.
I took a look at how 9P server is handling open() flags in 9P2000.L path.
I think we can do away with the valid_flags() function and simplify the
code. The reasoning is as follows:

O_NOCTTY: (If the file is a terminal, don't make it the controlling
terminal of the process even though the process does not have a controlling
terminal) By the time the control reaches 9P client it is clear that what
we have is not a terminal device. Hence it does not matter what we do with
this flag. In any case 9P server can filter this flag out before making the
syscall.

O_NONBLOCK: (Don't block if i) Can't read/write to the file ii) Can't get
locks) This has an impact on FIFOs, but also on file locks. Hence we can
pass it down to the system call.

O_ASYNC: From the manpage:

   O_ASYNC
          Enable signal-driven I/O: generate a signal (SIGIO by default,  but
          this  can be changed via fcntl(2)) when input or output becomes pos-
          sible on this file descriptor.  This feature is only available  for
          terminals,  pseudo-terminals,  sockets,  and (since Linux 2.6) pipes
          and FIFOs.  See fcntl(2) for further details.

Again, this does not make any impact on regular files handled by 9P. Also,
we don't want 9P server to receive SIGIO. Hence I think 9P server can
filter this flag out before making the syscall.

O_CLOEXEC: This flag makes sense only on the client. If guest user space
sets this flag the guest VFS will take care of calling close() on the fd if
an exec() happens. Hence 9P client need not be bothered with this flag.
Also I think QEMU will not do an exec, but if it does, it makes sense to
close these fds. Hence we can pass this flag down to the syscall.

O_CREAT: Since we are in open() path it means we have confirmed that the file
exists. Hence there is no need to pass O_CREAT flag down to the system. In fact
on some versions of glibc this causes problems, because we pass O_CREAT flag,
but don't have permission bits. Hence we can just mask this flag out.

So in summary:

Mask out:
O_NOCTTY
O_ASYNC
O_CREAT

Pass-through:
O_NONBLOCK
O_CLOEXEC
Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Signed-off-by: NArun R Bharadwaj <arun@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Signed-off-by: NArun R Bharadwaj <arun@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

The arguments are wrong. Use qemu_mallocz directly
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

We should always use functions which don't follow
symlink on the server
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

This is equivalent to SM_PASSTHROUGH security model.
The only exception is, failure of privilige operation like chown
are ignored. This makes a passthrough like security model usable
for people who runs kvm as non root
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

With mapped security mode we use "user.virtfs" namespace is used
to store the virtFs related attributes. So hide it from user.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

TXATTRCREATE:  Prepare a fid for setting xattr value on a file system object.

 size[4] TXATTRCREATE tag[2] fid[4] name[s] attr_size[8] flags[4]
 size[4] RXATTRWALK tag[2]

txattrcreate gets a fid pointing to xattr. This fid can later be
used to get set the xattr value.

flag value is derived from set Linux setxattr. The manpage says
"The flags parameter can be used to refine the semantics of the operation.
XATTR_CREATE specifies a pure create, which fails if the named attribute
exists already. XATTR_REPLACE specifies a pure replace operation, which
fails if the named attribute does not already exist. By default (no flags),
the extended attribute will be created if need be, or will simply replace
the value if the attribute exists."

The actual setxattr operation happens when the fid is clunked. At that point
the written byte count and the attr_size specified in TXATTRCREATE should be
same otherwise an error will be returned.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

TXATTRWALK: Descend a ATTR namespace

 size[4] TXATTRWALK tag[2] fid[4] newfid[4] name[s]
 size[4] RXATTRWALK tag[2] size[8]

txattrwalk gets a fid pointing to xattr. This fid can later be
used to get read the xattr value. If name is NULL the fid returned
can be used to get the list of extended attribute associated to
the file system object.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

We want to add type specific operation during read/write
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Implement 9p2000.L version of open(LOPEN) interface in qemu 9p server.

For LOPEN, no need to convert the flags to and from 9p mode to VFS mode.

Synopsis:

    size[4] Tlopen tag[2] fid[4] mode[4]

    size[4] Rlopen tag[2] qid[13] iounit[4]

Current qemu 9p server does not support following flags:
    O_NOCTTY, O_NONBLOCK, O_ASYNC & O_CLOEXEC

[Fix mode format - jvrao@linux.vnet.ibm.com]
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

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

Implement the 2000.L rename operation. A new function
v9fs_complete_rename is introduced that acts as a common entry point
for 2000.L rename operation and 2000.U rename opearation (via wstat).
As part of this change the field 'nname' (used only for rename) is
removed from the structure V9fsWstatState. Instead a new structure
V9fsRenameState is used for rename operations both by 2000.U and 2000.L
code paths. Both 2000.U and 2000.L rename code paths construct the
V9fsRenameState structure and passes that to v9fs_complete_rename
function.

Changes from previous version:
 Use qemu_mallocz to initialize
 Use strcpy,strcat functions instead of memcpy
 Changed the variable name to newdirfid
 Introduced post rename function
 Error checking
 Removed nname field from V9fsWstatState
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Synopsis

    size[4] Tmkdir tag[2] fid[4] name[s] mode[4] gid[4]

    size[4] Rmkdir tag[2] qid[13]

Description

    mkdir asks the file server to create a directory with given name,
    mode and gid. The qid for the new directory is returned with
    the mkdir reply message.

Note: 72 is selected as the opcode for TMKDIR from the reserved list.
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
[jvrao@linux.vnet.ibm.com: Fix perm handling when creating directory]
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Implement TMKNOD as part of 2000.L Work

Synopsis

    size[4] Tmknod tag[2] fid[4] name[s] mode[4] major[4] minor[4] gid[4]

    size[4] Rmknod tag[2] qid[13]

Description

    mknod asks the file server to create a device node with given device
    type, mode and gid. The qid for the new device node is returned with
    the mknod reply message.
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

SYNOPSIS

    size[4] Tlcreate tag[2] fid[4] name[s] flags[4] mode[4] gid[4]

    size[4] Rlcreate tag[2] qid[13] iounit[4]

DESCRIPTION

The Tlreate request asks the file server to create a new regular file with the
name supplied, in the directory (dir) represented by fid.
The mode argument specifies the permissions to use. New file is created with
the uid if the fid and with supplied gid.

The flags argument represent Linux access mode flags with which the caller
is requesting to open the file with. Protocol allows all the Linux access
modes but it is upto the server to allow/disallow any of these acess modes.
If the server doesn't support any of the access mode, it is expected to
return error.

To start with we will not restricit/limit any Linux flags on this server.
If needed, We can start restricting as we move forward with various use cases.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

This patch implements creating a symlink for TSYMLINK request
and responds with RSYMLINK. In the case of error, we return RERROR.

SYNOPSIS

    size[4] Tsymlink tag[2] fid[4] name[s] symtgt[s] gid[4]

    size[4] Rsymlink tag[2] qid[13]

    DESCRIPTION

    Create a symbolic link named 'name' pointing to 'symtgt'.
    gid represents the effective group id of the caller.
    The  permissions of a symbolic link are irrelevant hence it is omitted
    from the protocol.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Create a Hardlink.

SYNOPSIS

size[4] Tlink tag[2] dfid[4] oldfid[4] newpath[s]

size[4] Rlink tag[2]

DESCRIPTION

Create a link 'newpath' in directory pointed by dfid linking to oldfid path.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

SYNOPSIS

      size[4] Tsetattr tag[2] attr[n]

      size[4] Rsetattr tag[2]

   DESCRIPTION

      The setattr command changes some of the file status information.
      attr resembles the iattr structure used in Linux kernel. It
      specifies which status parameter is to be changed and to what
      value. It is laid out as follows:

         valid[4]
            specifies which status information is to be changed. Possible
            values are:
            ATTR_MODE       (1 << 0)
            ATTR_UID        (1 << 1)
            ATTR_GID        (1 << 2)
            ATTR_SIZE       (1 << 3)
            ATTR_ATIME      (1 << 4)
            ATTR_MTIME      (1 << 5)
            ATTR_CTIME      (1 << 5)
            ATTR_ATIME_SET  (1 << 7)
            ATTR_MTIME_SET  (1 << 8)

            The last two bits represent whether the time information
            is being sent by the client's user space. In the absense
            of these bits the server always uses server's time.

         mode[4]
            File permission bits

         uid[4]
            Owner id of file

         gid[4]
            Group id of the file

         size[8]
            File size

         atime_sec[8]
            Time of last file access, seconds

         atime_nsec[8]
            Time of last file access, nanoseconds

         mtime_sec[8]
            Time of last file modification, seconds

         mtime_nsec[8]
            Time of last file modification, nanoseconds

Explanation of the patches:
--------------------------

*) The kernel just copies relevent contents of iattr structure to p9_iattr_dotl
   structure and passes it down to the client. The only check it has is calling
   inode_change_ok()
*) The p9_iattr_dotl structure does not have ctime and ia_file parameters because
   I don't think these are needed in our case. The client user space can request
   updating just ctime by calling chown(fd, -1, -1). This is handled on server
   side without a need for putting ctime on the wire.
*) The server currently supports changing mode, time, ownership and size of the
   file.
*) 9P RFC says "Either all the changes in wstat request happen, or none of them
   does: if the request succeeds, all changes were made; if it fails, none were."
   I have not done anything to implement this specifically because I don't see
   a reason.

[jvrao@linux.vnet.ibm.com: Parts of code for handling chown(-1,-1)
Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Currently v9fs_do_utimensat takes a V9fsStat argument and builds
timespec structures. It sets tv_nsec values to 0 by default. Instead
of this it should take struct timespec[2] and pass it down to the
system directly. This will make it more generic and useful
elsewhere.
Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

    Current code resets file's atime to 0 when there is a change in mtime.
    This results in resetting the atime to "1970-01-01 05:30:00". For
    example, truncate -s 0 filename results in changing the mtime to the
    truncate time, but resets the atime to "1970-01-01 05:30:00". utime
    system call does not have any provision to set only mtime or atime. So
    change v9fs_wstat_post_chmod function to use utimensat function to change
    the atime and mtime fields. If tv_nsec field is set to the special value
    "UTIME_OMIT", corresponding file time stamp is not updated.
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

           SYNOPSIS

              size[4] Tgetattr tag[2] fid[4] request_mask[8]

              size[4] Rgetattr tag[2] lstat[n]

           DESCRIPTION

              The getattr transaction inquires about the file identified by fid.
              request_mask is a bit mask that specifies which fields of the
              stat structure is the client interested in.

              The reply will contain a machine-independent directory entry,
              laid out as follows:

                 st_result_mask[8]
                    Bit mask that indicates which fields in the stat structure
                    have been populated by the server

                 qid.type[1]
                    the type of the file (directory, etc.), represented as a bit
                    vector corresponding to the high 8 bits of the file's mode
                    word.

                 qid.vers[4]
                    version number for given path

                 qid.path[8]
                    the file server's unique identification for the file

                 st_mode[4]
                    Permission and flags

                 st_uid[4]
                    User id of owner

                 st_gid[4]
                    Group ID of owner

                 st_nlink[8]
                    Number of hard links

                 st_rdev[8]
                    Device ID (if special file)

                 st_size[8]
                    Size, in bytes

                 st_blksize[8]
                    Block size for file system IO

                 st_blocks[8]
                    Number of file system blocks allocated

                 st_atime_sec[8]
                    Time of last access, seconds

                 st_atime_nsec[8]
                    Time of last access, nanoseconds

                 st_mtime_sec[8]
                    Time of last modification, seconds

                 st_mtime_nsec[8]
                    Time of last modification, nanoseconds

                 st_ctime_sec[8]
                    Time of last status change, seconds

                 st_ctime_nsec[8]
                    Time of last status change, nanoseconds

                 st_btime_sec[8]
                    Time of creation (birth) of file, seconds

                 st_btime_nsec[8]
                    Time of creation (birth) of file, nanoseconds

                 st_gen[8]
                    Inode generation

                 st_data_version[8]
                    Data version number

              request_mask and result_mask bit masks contain the following bits
                 #define P9_STATS_MODE          0x00000001ULL
                 #define P9_STATS_NLINK         0x00000002ULL
                 #define P9_STATS_UID           0x00000004ULL
                 #define P9_STATS_GID           0x00000008ULL
                 #define P9_STATS_RDEV          0x00000010ULL
                 #define P9_STATS_ATIME         0x00000020ULL
                 #define P9_STATS_MTIME         0x00000040ULL
                 #define P9_STATS_CTIME         0x00000080ULL
                 #define P9_STATS_INO           0x00000100ULL
                 #define P9_STATS_SIZE          0x00000200ULL
                 #define P9_STATS_BLOCKS        0x00000400ULL

                 #define P9_STATS_BTIME         0x00000800ULL
                 #define P9_STATS_GEN           0x00001000ULL
                 #define P9_STATS_DATA_VERSION  0x00002000ULL

                 #define P9_STATS_BASIC         0x000007ffULL
                 #define P9_STATS_ALL           0x00003fffULL

        This patch implements the client side of getattr implementation for 9P2000.L.
        It introduces a new structure p9_stat_dotl for getting Linux stat information
        along with QID. The data layout is similar to stat structure in Linux user
        space with the following major differences:

        inode (st_ino) is not part of data. Instead qid is.

        device (st_dev) is not part of data because this doesn't make sense on the
        client.

        All time variables are 64 bit wide on the wire. The kernel seems to use
        32 bit variables for these variables. However, some of the architectures
        have used 64 bit variables and glibc exposes 64 bit variables to user
        space on some architectures. Hence to be on the safer side we have made
        these 64 bit in the protocol. Refer to the comments in
        include/asm-generic/stat.h

        There are some additional fields: st_btime_sec, st_btime_nsec, st_gen,
        st_data_version apart from the bitmask, st_result_mask. The bit mask
        is filled by the server to indicate which stat fields have been
        populated by the server. Currently there is no clean way for the
        server to obtain these additional fields, so it sends back just the
        basic fields.
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com>

Compute iounit based on the host filesystem block size and pass it to
client with open/create response. Also return iounit as statfs's f_bsize
for optimal block size transfers.
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Reviewd-by: NSripathi Kodi <sripathik@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

This patch implements the server part of readdir() implementation for
9p2000.L

    SYNOPSIS

    size[4] Treaddir tag[2] fid[4] offset[8] count[4]
    size[4] Rreaddir tag[2] count[4] data[count]

    DESCRIPTION

    The readdir request asks the server to read the directory specified by 'fid'
    at an offset specified by 'offset' and return as many dirent structures as
    possible that fit into count bytes. Each dirent structure is laid out as
    follows.

            qid.type[1]
              the type of the file (directory, etc.), represented as a bit
              vector corresponding to the high 8 bits of the file's mode
              word.

            qid.vers[4]
              version number for given path

            qid.path[8]
              the file server's unique identification for the file

            offset[8]
              offset into the next dirent.

            type[1]
              type of this directory entry.

            name[256]
              name of this directory entry.
Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com>
Reviewed-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com>

In v9fs_remove_post_remove() we currently ignore the error returned by
the previous call to remove() and return an error only if freeing the
fid fails. However, the client expects to see the error from remove().
Currently the client falsely thinks that the remove call has always
succeeded. For example, doing rmdir on a non-empty directory does
not return ENOTEMPTY.

With this patch we ignore the error from free_fid(). The client cannot
use this error value anyway.
Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Implement statfs support in qemu server based on Sripathi's
initial statfs patch.
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Make 9P server recognize 9P2000.L protocol version
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Based on a patch from Mark McLoughlin, this patch introduces a new
bottom half packet transmitter that avoids the latency imposed by
the tx_timer approach.  Rather than scheduling a timer when a TX
packet comes in, schedule a bottom half to be run from the iothread.
The bottom half handler first attempts to flush the queue with
notification disabled (this is where we could race with a guest
without txburst).  If we flush a full burst, reschedule immediately.
If we send short of a full burst, try to re-enable notification.
To avoid a race with TXs that may have occurred, we must then
flush again.  If we find some packets to send, the guest it probably
active, so we can reschedule again.

tx_timer and tx_bh are mutually exclusive, so we can re-use the
tx_waiting flag to indicate one or the other needs to be setup.
This allows us to seamlessly migrate between timer and bh TX
handling.

The bottom half handler becomes the new default and we add a new
tx= option to virtio-net-pci.  Usage:

-device virtio-net-pci,tx=timer # select timer mitigation vs "bh"
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

De-couple this from the timer since we might want to use
different backends to send the packet.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

If virtio_net_flush_tx() is called with notification disabled, we can
race with the guest, processing packets at the same rate as they
get produced.  The trouble is that this means we have no guaranteed
exit condition from the function and can spend minutes in there.
Currently flush_tx is only called with notification on, which seems
to limit us to one pass through the queue per call.  An upcoming
patch changes this.

Also add an option to set this value on the command line as different
workloads may wish to use different values.  We can't necessarily
support any random value, so this is a developer option: x-txburst=
Usage:

-device virtio-net-pci,x-txburst=64 # 64 packets per tx flush

One pass through the queue (256) seems to be a good default value
for this, balancing latency with throughput.  We use a signed int
for x-txburst because 2^31 packets in a burst would take many, many
minutes to process and it allows us to easily return a negative
value value from virtio_net_flush_tx() to indicate a back-off
or error condition.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Add an option to make the TX mitigation timer adjustable as a device
option.  The 150us hard coded default used currently is reasonable,
but may not be suitable for all workloads, this gives us a way to
adjust it using a single binary.  We can't support any random option
though, so use the "x-" prefix to indicate this is a developer
option.  Usage:

-device virtio-net-pci,x-txtimer=500000,... # .5ms timeout
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

use the new tap APIs to set header length
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Add APIs to control host header length. First user
will be vhost-net.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Make host vnet header length a structure field in
preparation for using this support in linux kernel.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Patch b0b90007 made
TOR valuer incorrect: the spec says it should always
include the CRC field.
No one seems to use this field, but better to stick to spec.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

bswap_NN() variants are not always available in CONFIG_MACHINE_BSWAP_H case
and bswapNN() are public APIs in "bswap.h".
Signed-off-by: NIzumi Tsutsui <tsutsui@ceres.dti.ne.jp>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

Signed-off-by: NSerge Ziryukin <ftrvxmtrx@gmail.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

stat() fields can be more or less anything depending on configuration, cast
explicitly to uint64_t to avoid printf() format mismatches.
Signed-off-by: NAvi Kivity <avi@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

When making copy of arguments we were doing partial copy
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>