Use the typedef to declare tag in AUTOVAR. Do not allocate 9P tags in
advance in AUTOVAR, do it right before we need them. Do no reuse tags.
If we are going to use sequential tags, we might as well try to make
them really sequential.

mount_9p: enable to communicate with vio9p via its character device file

With this feature, we can mount an exported filesystem by a VM host via
virtio-9p.

Handle Rerror and return errno correctly (only for 9P2000.u for now)

mount_9p: add initial support for 9P2000.u

The implementation enables to work with a server talking 9P2000.u. However, it
doesn't use the extended fields yet; it just ignores those of received messages
and sets "please ignore" values to those of sending messages such as zero-length
strings and maximum unsigned values.

The feature is enabled by the -u option.

branches: 1.12.70;
Rototill.

Ok, ok, a few more words about it: stop holding puffs_cc as a holy
value and passing it around to almost every possible place (popquiz:
which kernel variable does this remind you of?). Instead, pass
the natural choice, puffs_usermount, and fetch puffs_cc via
puffs_cc_getcc() only in routines which actually need it. This
not only simplifies code, but (thanks to the introduction of
puffs_cc_getcc()) enables constructs which weren't previously sanely
possible, say layering as a curious example.

There's still a little to do on this front, but this was the major
fs interface blast.

adapt to new cmpfb signature

branches: 1.10.4;
support standard user@host:path mount argument

adapt to puffs_framebuf changes

Enhance the GETRESPONSE, JUSTSEND and SENDCB macros to process the
return value from the network layer.

adapt to "step 3" of puffs_framebuf changes

adapt to puffs_framebuf changes

If mode is set, the uppermost byte specifying the type must be
correctly, otherwise the file server will attempt a conversion.
Specifically, if the directory bit is not set when changing the
permissions for a directory, a conversion from directory to regular
file would be attempted and naturally it being unsupported the
whole chmod would fail. So supply the file type as part of the
file mode.

Close file handles in inactive instead of close - a memory mapping
may still be active after a vnode is closed

Adapt to use puffs_framebuf. This gets rid of most of the duplicated
code between mount_psshfs and mount_9p and clarifies the code
structure.

Alter the strategy for reading/writing a bit. First of all, use
PUFFS_KFLAG_WTCACHE. Second, create separate fids for reading and
writing. If opening for read, open a read-only fid and for write
a write-only fid; use these for reading and writing. When the
open-count for a node drops to zero, clunk both. This avoids hitting
the fid limit when accessing large directory hierarchies.

Two problems remain:
* does not take credentials into account, although we can only mount
the remote 9P file server with one set of credentials, so not a
huge worry
* doesn't work for the open/mmap/close/access_memory_window case, but
that will require some further kernel changes

mount_9p: mount a file server using the Plan9 file sharing protocol

Works, but lots of little things to nibble on:
* fix permissions to work better
* limit the amount of open files required
* do constant folding with psshfs code
* support authentication
etcetc.

mount_9p: enable to communicate with vio9p via its character device file

With this feature, we can mount an exported filesystem by a VM host via
virtio-9p.

Handle Rerror and return errno correctly (only for 9P2000.u for now)

mount_9p: add initial support for 9P2000.u

The implementation enables to work with a server talking 9P2000.u. However, it
doesn't use the extended fields yet; it just ignores those of received messages
and sets "please ignore" values to those of sending messages such as zero-length
strings and maximum unsigned values.

The feature is enabled by the -u option.

branches: 1.12.70;
Rototill.

Ok, ok, a few more words about it: stop holding puffs_cc as a holy
value and passing it around to almost every possible place (popquiz:
which kernel variable does this remind you of?). Instead, pass
the natural choice, puffs_usermount, and fetch puffs_cc via
puffs_cc_getcc() only in routines which actually need it. This
not only simplifies code, but (thanks to the introduction of
puffs_cc_getcc()) enables constructs which weren't previously sanely
possible, say layering as a curious example.

There's still a little to do on this front, but this was the major
fs interface blast.

adapt to new cmpfb signature

branches: 1.10.4;
support standard user@host:path mount argument

adapt to puffs_framebuf changes

Enhance the GETRESPONSE, JUSTSEND and SENDCB macros to process the
return value from the network layer.

adapt to "step 3" of puffs_framebuf changes

adapt to puffs_framebuf changes

If mode is set, the uppermost byte specifying the type must be
correctly, otherwise the file server will attempt a conversion.
Specifically, if the directory bit is not set when changing the
permissions for a directory, a conversion from directory to regular
file would be attempted and naturally it being unsupported the
whole chmod would fail. So supply the file type as part of the
file mode.

Close file handles in inactive instead of close - a memory mapping
may still be active after a vnode is closed

Adapt to use puffs_framebuf. This gets rid of most of the duplicated
code between mount_psshfs and mount_9p and clarifies the code
structure.

Alter the strategy for reading/writing a bit. First of all, use
PUFFS_KFLAG_WTCACHE. Second, create separate fids for reading and
writing. If opening for read, open a read-only fid and for write
a write-only fid; use these for reading and writing. When the
open-count for a node drops to zero, clunk both. This avoids hitting
the fid limit when accessing large directory hierarchies.

Two problems remain:
* does not take credentials into account, although we can only mount
the remote 9P file server with one set of credentials, so not a
huge worry
* doesn't work for the open/mmap/close/access_memory_window case, but
that will require some further kernel changes

mount_9p: mount a file server using the Plan9 file sharing protocol

Works, but lots of little things to nibble on:
* fix permissions to work better
* limit the amount of open files required
* do constant folding with psshfs code
* support authentication
etcetc.

Handle Rerror and return errno correctly (only for 9P2000.u for now)

mount_9p: add initial support for 9P2000.u

The implementation enables to work with a server talking 9P2000.u. However, it
doesn't use the extended fields yet; it just ignores those of received messages
and sets "please ignore" values to those of sending messages such as zero-length
strings and maximum unsigned values.

The feature is enabled by the -u option.

Rototill.

Ok, ok, a few more words about it: stop holding puffs_cc as a holy
value and passing it around to almost every possible place (popquiz:
which kernel variable does this remind you of?). Instead, pass
the natural choice, puffs_usermount, and fetch puffs_cc via
puffs_cc_getcc() only in routines which actually need it. This
not only simplifies code, but (thanks to the introduction of
puffs_cc_getcc()) enables constructs which weren't previously sanely
possible, say layering as a curious example.

There's still a little to do on this front, but this was the major
fs interface blast.

adapt to new cmpfb signature

branches: 1.10.4;
support standard user@host:path mount argument

adapt to puffs_framebuf changes

Enhance the GETRESPONSE, JUSTSEND and SENDCB macros to process the
return value from the network layer.

adapt to "step 3" of puffs_framebuf changes

adapt to puffs_framebuf changes

If mode is set, the uppermost byte specifying the type must be
correctly, otherwise the file server will attempt a conversion.
Specifically, if the directory bit is not set when changing the
permissions for a directory, a conversion from directory to regular
file would be attempted and naturally it being unsupported the
whole chmod would fail. So supply the file type as part of the
file mode.

Close file handles in inactive instead of close - a memory mapping
may still be active after a vnode is closed

Adapt to use puffs_framebuf. This gets rid of most of the duplicated
code between mount_psshfs and mount_9p and clarifies the code
structure.

Alter the strategy for reading/writing a bit. First of all, use
PUFFS_KFLAG_WTCACHE. Second, create separate fids for reading and
writing. If opening for read, open a read-only fid and for write
a write-only fid; use these for reading and writing. When the
open-count for a node drops to zero, clunk both. This avoids hitting
the fid limit when accessing large directory hierarchies.

Two problems remain:
* does not take credentials into account, although we can only mount
the remote 9P file server with one set of credentials, so not a
huge worry
* doesn't work for the open/mmap/close/access_memory_window case, but
that will require some further kernel changes

mount_9p: mount a file server using the Plan9 file sharing protocol

Works, but lots of little things to nibble on:
* fix permissions to work better
* limit the amount of open files required
* do constant folding with psshfs code
* support authentication
etcetc.

mount_9p: add initial support for 9P2000.u

The implementation enables to work with a server talking 9P2000.u. However, it
doesn't use the extended fields yet; it just ignores those of received messages
and sets "please ignore" values to those of sending messages such as zero-length
strings and maximum unsigned values.

The feature is enabled by the -u option.

Rototill.

Ok, ok, a few more words about it: stop holding puffs_cc as a holy
value and passing it around to almost every possible place (popquiz:
which kernel variable does this remind you of?). Instead, pass
the natural choice, puffs_usermount, and fetch puffs_cc via
puffs_cc_getcc() only in routines which actually need it. This
not only simplifies code, but (thanks to the introduction of
puffs_cc_getcc()) enables constructs which weren't previously sanely
possible, say layering as a curious example.

There's still a little to do on this front, but this was the major
fs interface blast.

adapt to new cmpfb signature

branches: 1.10.4;
support standard user@host:path mount argument

adapt to puffs_framebuf changes

Enhance the GETRESPONSE, JUSTSEND and SENDCB macros to process the
return value from the network layer.

adapt to "step 3" of puffs_framebuf changes

adapt to puffs_framebuf changes

If mode is set, the uppermost byte specifying the type must be
correctly, otherwise the file server will attempt a conversion.
Specifically, if the directory bit is not set when changing the
permissions for a directory, a conversion from directory to regular
file would be attempted and naturally it being unsupported the
whole chmod would fail. So supply the file type as part of the
file mode.

Close file handles in inactive instead of close - a memory mapping
may still be active after a vnode is closed

Adapt to use puffs_framebuf. This gets rid of most of the duplicated
code between mount_psshfs and mount_9p and clarifies the code
structure.

Alter the strategy for reading/writing a bit. First of all, use
PUFFS_KFLAG_WTCACHE. Second, create separate fids for reading and
writing. If opening for read, open a read-only fid and for write
a write-only fid; use these for reading and writing. When the
open-count for a node drops to zero, clunk both. This avoids hitting
the fid limit when accessing large directory hierarchies.

Two problems remain:
* does not take credentials into account, although we can only mount
the remote 9P file server with one set of credentials, so not a
huge worry
* doesn't work for the open/mmap/close/access_memory_window case, but
that will require some further kernel changes

mount_9p: mount a file server using the Plan9 file sharing protocol

Works, but lots of little things to nibble on:
* fix permissions to work better
* limit the amount of open files required
* do constant folding with psshfs code
* support authentication
etcetc.