Plan 9 from Bell Labs’s /usr/web/sources/patch/applied/fossil-snap-deadlock/fossilcons.orig

Copyright © 2021 Plan 9 Foundation.
Distributed under the MIT License.
Download the Plan 9 distribution.


.TH FOSSILCONS 8
.SH NAME
fossilcons \- fossil console commands
.SH SYNOPSIS
.B
con /srv/fscons
.PP
.PD 0.1
.B .
.I file
.PP
.B 9p
.I T-message
...
.PP
.B bind
[
.B -b|-a|-c|-bc|-ac
]
.I new
.I old
.PP
.B dflag
.PP
.B echo
[
.B -n
]
[
.I arg
...
]
.PP
.B listen
[
.B -INd
]
[
.I address
]
.PP
.B msg
[
.B -m
.I nmsg
]
[
.B -p
.I nproc
]
.PP
.B printconfig
.PP
.B srv
[
.B -APWdp
]
.I name
.PP
.B uname
.I name
[
.I id
|
.BI : id
|
.BI % newname
|
.BI = leader
|
.BI + member
|
.BI - member
]
.PP
.B users
[
.B -d
|
.B -r
.I file
]
[
.B -w
]
.PP
.B who
.sp
.PP
.B fsys
.I name
.PP
.B fsys
.I name
.B config
[
.I device
]
.PP
.B fsys
.I name
.B venti
[
.I host
]
.PP
.B fsys
.I name
.B open
[
.B -APVWar
]
[
.B -c
.I ncache
]
.PP
[
.B fsys
.I name
]
.B close
.PP
.B fsys
.I name
.B unconfig
.sp
.PP
[
.B fsys
.I name
]
.B bfree
.I addr
.PP
[
.B fsys
.I name
]
.B block
.I addr
.I offset
[
.I count
[
.I data
]]
.PP
.in +1i
.ti -1i
[
.B fsys
.I name
]
.B check
[
.B pblock
] [
.B pdir
] [
.B pfile
] [
.B bclose
] [
.B clri
] [
.B clre
] [
.B clrp
] [
.B fix
] [
.B venti
] [
.B snapshot
]
.PP
[
.B fsys
.I name
]
.B clre
.I addr
.I offsets
\&...
.PP
[
.B fsys
.I name
]
.B clri
.I files
\&...
.PP
[
.B fsys
.I name
]
.B clrp
.I addr
.I offset
\&...
.PP
[
.B fsys
.I name
]
.B create
.I path
.I uid
.I gid
.I perm
.PP
[
.B fsys
.I name
]
.B df
.PP
[
.B fsys
.I name
]
.B epoch
[[
.B -ry
]
.I n
]
.PP
[
.B fsys
.I name
]
.B halt
.PP
[
.B fsys
.I name
]
.B label
.I addr
[
.I type
.I state
.I epoch
.I epochclose
.I tag
]
.PP
[
.B fsys
.I name
]
.B remove
.I files
\&...
.PP
[
.B fsys
.I name
]
.B snap
[
.B -a
]
[
.B -s
.I src
]
[
.B -d
.I dst
]
.PP
[
.B fsys
.I name
]
.B snapclean
[
.I timeout
]
.PP
[
.B fsys
.I name
]
.B snaptime
[
.B -a
.I hhmm
]
[
.B -s
.I interval
]
[
.B -t
.I timeout
]
.PP
[
.B fsys
.I name
]
.B stat
.IR files ...
.PP
[
.B fsys
.I name
]
.B sync
.PP
[
.B fsys
.I name
]
.B unhalt
.PP
[
.B fsys
.I name
]
.B vac
.I dir
.PP
[
.B fsys
.I name
]
.B wstat
.I file
.I elem
.I uid
.I gid
.I perm
.I length
.SH DESCRIPTION
These are configuration and maintenance commands
executed at the console of a 
.IR fossil (4)
file server.
The commands are split into three groups above:
file server configuration,
file system configuration,
and file system maintenance.
This manual page is split in the same way.
.SS File server configuration
.PP
The
dot
.RI ( . )
command
reads
.IR file ,
treating each line as a command to be executed.
Blank lines and lines beginning with a 
.L #
character are ignored.
Errors during execution are printed but do not stop the script.
Note that
.I file
is a file in the name space in which
.I fossil
was started,
.I not
a file in any file system served by
.IR fossil .
.PP
.I 9p
executes a 9P transaction; the arguments
are in the same format used by
.IR 9pcon (8).
.PP
.I Bind
behaves similarly to
.IR bind (1).
It is useful when fossil
is started without devices it needs configured
into its namespace.
.PP
.I Dflag
toggles the debug flag and prints the new setting.
When the debug flag is set, all protocol messages
and information about authentication is printed to
standard error.
.PP
.I Echo
behaves identically to
.IR echo (1),
writing to the console.
.PP
.I Listen
manages the network addresses at which
fossil is listening.
With no arguments,
.I listen
prints the current list of addresses and their network directories.
With one argument, listen
.I address
starts a new listener at
.IR address ;
the
.B -d
flag causes 
.I listen
to remove the listener
at the given address.
By default, the user
.I none
is only allowed to attach on a connection after
at least one other user has successfully attached.
The
.B -N
flag allows connections from
.I none
at any time.
The
.B -I
flag causes
.I fossil
to check the IP address of incoming connections
against
.BR /mnt/ipok ,
rejecting attaches from disallowed addresses.
This mechanism is not intended for general use.
The server
.I sources.cs.bell-labs.com
uses it to comply with U.S. crytography
export regulations.
.PP
.I Msg
prints the maximum internal 9P message queue size
and the maximum number of 9P processes to
allocate for serving the queue.
The
.B -m
and
.B -p
options set the two variables.
.PP
.I Printconfig
prints the
.B config
line for each configured file system
and prints the
.B venti
line, if any, used to configure this file server.
.PP
.I Srv
behaves like listen but uses
.BI /srv/ name
rather than a network address.
With the
.B -p
flag, 
.I srv 
edits a list of console services rather than 9P services.
With no arguments,
.I srv
prints the current list of services.
With one argument, srv
.I name
starts a new service at
.IR /srv/name ;
the
.B -d
flag causes 
.I srv
to remove the named service.
See the
.I [fsys] open
command below for a description of the
.B -APW
options.
.PP
.I Uname
manipulates entries in the user table.
There is no distinction between users and groups:
a user is a group with one member.
For each user, the user table records:
.TF \fImembers
.PD
.TP
.I id
the string used to represent this user in the on-disk structures
.TP
.I name
the string used to represent this user in the 9P protocol
.TP
.I leader
the group's leader (see
.IR stat (5)
for a description of the special privileges held by a group leader)
.TP
.I members
a comma-separated list of members in this group
.PP
The
.I id
and
.I name
are usually the same string, but need not be.
Once an
.I id
is used in file system structures archived to Venti,
it is impossible to change those disk structures,
and thus impossible to rename the
.IR id .
The translation from
.I name
to
.I id
allows the appearance of renaming the user even
though the on-disk structures still record the old name.
(In a conventional Unix file system, the
.I id
is stored as a small integer rather than a string.)
.I Leader
and
.I members
are names, not ids.
.PP
The first argument to
.I uname
is the
.I name
of a user.
The second argument is a verb, one of:
.TF \fI%newname
.PD
.TP
.I id
create a user with name
.RI ` name '
and id
.RI ` id ;'
also create a home directory
.BI /active/usr/ uname \fR
.TP
.BI : id
create a user with name
.RI ` name '
and id
.RI ` id ,'
but do not create a home directory
.TP
.BI % newname
rename user
.RI ` name '
to
.RI ` newname ,'
throughout the user table
.TP
.BI = leader
set
.IR name 's
group leader
to
.IR leader .
.TP
.BI =
remove
.IR name 's
group leader; then all members will be
considered leaders
.TP
.BI + member
add
.I member
to
.IR name 's
list of members
.TP
.BI - member
remove
.I member
from
.IR name 's
list of members
.LP
If the verb is omitted, the entire entry for
.I name
is printed, in the form
`\fIid\fL:\fIname\fL:\fIleader\fL:\fImembers\fR.'
.LP
The end of this manual page gives examples.
.PP
.I Users
manipulates the user table.
The user table is a list of lines in the form printed
by the
.I uname
command.
The
.B -d
flag resets the user table with the default:
.IP
.EX
adm:adm:adm:sys
none:none::
noworld:noworld::
sys:sys::
glenda:glenda:glenda:
.EE
.PP
Except
.BR glenda ,
these users are mandatory: they must appear in all user
files and cannot be renamed.
.PP
The
.B -r
flag reads a user table from the named
.I file
in file system
.BR main .
The
.B -w
flag writes the table to
.B /active/adm/users
on the file system
.BR main .
.B /active/adm
and
.B /active/adm/users
will be created if they do not exist.
.PP
.I Users
.B -r
.B /active/adm/users
is automatically executed when the file system
.B main
is opened.
.PP
.I Users
.B -w
is automatically executed after each change to the user
table by the
.I uname
command.
.PP
.I Who
prints a list of users attached to each active connection.
.SS File system configuration
.I Fsys
sets the current file system to
.IR name ,
which must be configured and open (q.v.).
The current file system name is
displayed as the file server prompt.
The special name
.B all
stands for all file systems;
commands applied to
.B all
are applied to each file system in turn.
The commands
.BR config ,
.BR open ,
.BR venti ,
and
.B close
cannot be applied to
.BR all .
.PP
.I Fsys
takes as an optional argument
(after
.BR name )
a command to execute on the named file system.
Most commands require that the named file system
be configured and open; these commands can be invoked
without the
.BI fsys " name
prefix, in which case the current file system is used.
A few commands
.RB ( config ,
.BR open ,
and
.BR unconfig )
operate on unopened file systems; they require the prefix.
.PP
.I Config
creates a new file system named
.I name
using disk file
.IR device .
This just adds an entry to fossil's internal table.
If
.I device
is missing,
the
.I file
argument to
.IR fossil 's
.B -f
option will be used instead;
this allows the
.I fossil
configuration file to avoid naming the partition that it is embedded in,
making it more portable.
.PP
.I Venti
establishes a connection to the Venti server
.I host
(by default, the environment variable
.B $venti
or the network variable
.BR $venti )
for use by the named file system.
If no
.I venti
command is issued before
.IR open ,
the default Venti server will be used.
If the file system is open,
and was not opened with the
.B -V
flag,
the command redials the Venti server.
This can be used to reestablish broken connections.
It is not a good idea to use the command to switch
between Venti servers, since Fossil does not keep track
of which blocks are stored on which servers.
.PP
.I Open
opens the file system, reading the
root and super blocks and allocating an in-memory
cache for disk and Venti blocks.
The options are:
.TF "-c\fI ncache
.PD
.TP
.B -A
run with no authentication
.TP
.B -P
run with no permission checking
.TP
.B -V
do not attempt to connect to a Venti server
.TP
.B -W
allow wstat to make arbitrary changes to the user and group fields
.TP
.B -a
do not update file access times;
primarily to avoid wear on flash memories
.TP
.B -r
open the file system read-only
.TP
.BI -c " ncache
allocate an in-memory cache of 
.I ncache
(by default, 1000)
blocks
.PP
The
.I -APW
settings can be overridden on a per-connection basis
by the
.I srv
command above.
.PP
.I Close
flushes all dirty file system blocks to disk
and then closes the device file.
.PP
.I Unconfig
removes the named file system (which must be closed)
from fossil's internal table.
.br
.ne 3
.SS File system maintenance
.I Bfree
marks the block at disk address
.I addr
as available for allocation.
Before doing so, it prints a
.I label
command (q.v.)
that can be used to restore the block to its previous state.
.PP
.I Block
displays (in hexadecimal)
the contents of the block at disk address
.IR addr ,
starting at
.I offset
and continuing for
.I count
bytes or until the end of the block.
If 
.I data
(also hexadecimal)
is given, the contents in that range are
replaced with data.
When writing to a block,
.I block
prints the old and new contents,
so that the change is easily undone.
Editing blocks is discouraged.
.PP
.I Clre
zeros an entry from a disk block.
Before doing so, it prints a
.I block
command that can be used 
to restore the entry.
.PP
.I Clri
removes the internal directory entry
and abandons storage associated with
.IR files .
It ignores the usual rules for sanity, such as checking against
removing a non-empty directory.
A subsequent
.I flchk
(see
.IR fossil (4))
will identify the abandoned storage so it can be reclaimed with
.I bfree
commands.
.PP
.I Clrp
zeros a pointer in a disk block.
Before doing so, it prints a 
.I block
command that can be used to restore the entry.
.PP
.I Check
checks the file system for various inconsistencies.
If the file system is not already halted, it is halted for
the duration of the check.
If the archiver is currently sending a snapshot to Venti,
the check will refuse to run; the only recourse is to wait
for the archiver to finish.
.PP
A list of keyword options control the check.
The
.BR pblock ,
.BR pdir ,
and
.B pfile
options cause 
.I check
to print the name of each block, directory, or file encountered.
.PP
By default,
.I check
reports errors but does not fix them.
The
.BR bclose ,
.BR clri ,
.BR clre ,
and
.B clrp
options specify correcting actions that may be taken:
closing leaked blocks, clearing bad file directory entries,
clearing bad pointers, and clearing bad entries.
The
.B fix
option enables all of these; it is equivalent to
.B bclose
.B clri
.B clre
.BR clrp .
.PP
By default,
.I check
scans the portion of the active file system held in the write buffer,
avoiding blocks stored on Venti or used only in snapshots.
The
.B venti
option causes
.I check
to scan the portion of the file system stored on Venti,
and the
.B snapshot
option causes
.I check
to scan old snapshots.
Specifying
.B snapshot
causes
.I check
to take a long time;
specifying
.B venti
or
(worse)
.B venti
.B snapshot
causes
.I check
to take a very long time.
.PP
.I Create
creates a file on the current file system.
.I Uid
and
.I gid
are uids
.RI ( not
unames;
see the discussion above, in the description
of the 
.I uname
command).
.I Perm
is the low 9 bits of the permission mode of the file,
in octal.
The 
.BR a ,
.BR d ,
and
.B l
mode prefixes
set the append-only, directory, and lock bits.
The
.I perm
is formatted as described in the
.I stat
command;
creating files or directories with the
.BR snapshot (s)
bit set is not allowed.
.PP
.I Df
prints the amount of used disk space in the write buffer.
.PP
.I Epoch
sets the low file system epoch.
Snapshots in the file system are given increasing epoch numbers.
The file system maintains a low and a high epoch number,
and only allows access to snapshots in that range.
The low epoch number can be moved forward to discard old snapshots
and reclaim the disk space they occupy.
(The high epoch number is always the epoch of the currently
active file system.)
.PP
With no argument
.I epoch
reports the current low and high epoch numbers.
The command
``\fLepoch\fI n''\fR
is used to propose changing the low epoch to
.IR n .
In response, 
.I fossil
scans
.B /archive
and
.B /snapshot
for snapshots that would be discarded, printing their
epoch numbers and the
.I clri
commands necessary to remove them.
The epoch is changed only if no such paths are found.
The usual sequence of commands is (1) run epoch to
print the snapshots and their epochs, (2) clri some snapshots,
(3) run epoch again.
If the file system is completely full (there are no free blocks),
.I clri
may fail because it needs to allocate blocks.
For this situation,
the
.B -y
flag to epoch forces the epoch change even when
it means discarding currently accessible snapshots.
Note that when there are still snapshots in
.BR /archive ,
the archiver should take care
of those snapshots (moving the blocks from disk to Venti)
if you give it more time.
.PP
The
.B -r
flag to epoch causes it to remove any now-inaccessible
snapshot directories once it has changed the epoch.
This flag only makes sense in conjunction with the
.B -y
flag.
.PP
.I Epoch
is a very low-level way to retire snapshots.
The preferred way is by setting an automatic timer
with
.IR snaptime .
.PP
.I Halt
suspends all file system activity;
.I unhalt
resumes activity.
.PP
.I Label
displays and edits the label associated with a block.
When editing, a parameter of
.B -
means leave that field unchanged.
Editing labels is discouraged.
.PP
.I Remove
removes
.IR files .
.PP
.I Snap
takes a temporary snapshot of the current file system,
recording it in 
.BI /snapshot/ yyyy / mmdd / hhmm \fR,
as described in 
.IR fossil (4).
The
.B -a
flag causes 
.I snap
to take an archival snapshot, recording it in
.BI /archive/ yyyy / mmdd \fR,
also described in
.IR fossil (4).
By default the snapshot is taken of
.BR /active ,
the root of the active file system.
The 
.B -s
flag specifies a different source path.
The
.B -d
flag specifies a different destination path.
These  two flags are useful together for moving snapshots into
the archive tree.
.PP
.I Snapclean
immediately discards all snapshots that are more than
.I timeout
minutes old.
The default timeout is the one set by the
.I snaptime
command.
The discarding is a one-time event rather than
a recurring event as in
.IR snaptime .
.PP
.I Snaptime
displays and edits the times at which snapshots are automatically
taken.
An archival snapshot is taken once a day, at
.IR hhmm ,
while temporary snapshots are taken at multiples of
.I interval
minutes.
Temporary snapshots are discarded after they are
.I timeout
minutes old.
The snapshot cleanup runs every
.I timeout
minutes or once a day, whichever is more frequent,
so snapshots may grow to an age of almost twice the timeout
before actually being discarded.
With no arguments,
.I snaptime
prints the current snapshot times.
The
.B -a
and
.B -s
options set the archive and snapshot times.
An
.I hhmm
or
.I interval
of
.L none
can be used to disable that kind of automatic snapshot.
The
.B -t
option sets the snapshot timeout.
If
.I timeout
is
.LR none ,
temporary snapshots are not automatically discarded.
By default, all three times are set to
.LR none .
.PP
.I Stat
displays metadata for each of the named
.IR files ,
in the form:
.IP
.EX
stat \fIfile elem uid gid perm length
.EE
.LP
(Replacing
.B stat
with
.B wstat
yields a valid command.)
The
.I perm
is an octal number less than or equal to 777,
prefixed with any of the following letters
to indicate additional bits.
.IP
.EX
.ta +4n
a	\fRappend only
d	\fRdirectory
l	\fRexclusive use
s	\fRis the root of a snapshot
t	\fRtemporary bit
A	\fRMS-DOS archive bit
G	\fRsetgid
H	\fRMS-DOS hidden bit
L	\fRsymbolic link
S	\fRMS-DOS system bit
U	\fRsetuid
Y	\fRsticky
.EE
.PP
The bits denoted by capital letters are included
to support non-Plan 9 systems.
They are not made visible by the 9P protocol.
.PP
.I Sync
writes dirty blocks in memory to the disk.
.PP
.I Vac
prints the Venti score for a
.IR vac (1)
archive containing the tree rooted
at
.IR dir ,
which must already be archived to Venti
(typically
.IR dir
is a directory in the
.B /archive
tree).
.PP
.I Wstat
changes the metadata of the named
.IR file .
Specifying
.B -
for any of the fields means ``don't change.''
Attempts to change the
.B d
or
.B s
bits in the
.I perm
are silently ignored.
.SH EXAMPLES
.IR Sources ,
the Plan 9 distribution file server,
uses the following configuration file:
.IP
.EX
srv -p fscons.sources
srv -p fscons.sources.adduserd
srv sources
fsys main config /dev/sdC0/fossil.outside
fsys main open -c 25600
fsys main
users /active/adm/users
listen tcp!*!564
msg -m 40 -p 10
snaptime -a 0000 -s 15
.EE
.LP
The second console is used by the daemon
that creates new accounts.
.PP
To add a new user with
.I name
and
.I id
.B rob
and create his home directory:
.IP
.EX
uname rob rob
.EE
.PP
To create a new group
.B sys
(with no home directory)
and add
.B rob
to it:
.IP
.EX
uname sys :sys
uname sys +rob
.EE
.PP
To save an old (but not yet discarded) snapshot into the archive tree:
.IP
.EX
snap -a -s /snapshot/2003/1220/0700 -d /archive/2003/1220
.EE
.SH BUGS
It is prudent to avoid taking a snapshot at the same time as an
archival dump.
.I Fossil
has been seen to sometimes hang when they collide.
Snapshots are taken when
.BI time(0)/60% interval
is zero, so
an interval of 60 will take snapshots on the hour.
It's easiest to schedule the archival dumps to happen not exactly on the hour.

Bell Labs OSI certified Powered by Plan 9

(Return to Plan 9 Home Page)

Copyright © 2021 Plan 9 Foundation. All Rights Reserved.
Comments to webmaster@9p.io.