ref: 390e726c64ee2aca967617ac7f7fd2a44f27646b
dir: /man/mafs.8/
.TH MAFS 8
.SH NAME
block, find, free, reconcile, unused, updatefrees, used - file server maintenance
.SH SYNOPSIS
.PD 0
.PP
.B halt
.PP
.B sync
.PP
.B users
.PD
.PP
.B disk/block
.I drive
.I block_number
.PP
.B disk/find
.I drive
.I block_number
.PP
.B disk/free
.I drive
.PP
.B disk/reconcile
.I -u used_blocks_list_file
.I -F free_blocks_list_file
.I nblocks
.PP
.B disk/unused
.I used_blocks
.I nblocks
.PP
.B disk/used
.I drive
.PP
.B disk/updatefrees
.I drive
.I free_blocks_list_file
.I nblocks
.SH DESCRIPTION
Reading /adm/ctl prints the number of free, used and total blocks/megabytes. The following commands should be written to /adm/ctl of a
.IR mafs (4)
file server.
.PP
.I Halt
stops the mafs service after pending writes to the disk are completed.
.PP
.I Sync
blocks until all the pending writes to the disk are completed.
.PD
.PP
.I disk/block
Interpret the contents of a block based on the tag and write out a single formatted block based on the tag.
.PP
.I disk/find
traverses the directory heirarchy and identifies the file that a block number belongs to.
.PP
.I disk/find
traverses the directory heirarchy and identifies the file that a block number belongs to.
.PP
.I disk/free
shows the list of free blocks from the contents of /adm/frees.
.PP
.I disk/reconcile
reads two lists of block numbers and flags the common and missing blocks.
.PP
.I disk/unused
builds the list of free blocks. This should match the contents of /adm/frees.
.PP
.I disk/used
traverses the directory heirarchy and writes out all the used block numbers.
.PP
.I disk/updatefrees
changes the contents of /adm/frees.
.SH EXAMPLES
Check disk usage (traditional df) of a mafs mounted at /n/mafs_myservice.
.IP
.EX
cat /n/myservice/adm/ctl
.EE
.PP
Show the contents of block 22 in disk, tests/test.0/disk.
.IP
.EX
disk/block tests/test.0/disk 22
.EE
.PP
Find the file using block 17 in disk, tests/test.0/disk.
.IP
.EX
disk/find tests/test.0/disk 17
.EE
.PP
From the contents of /adm/frees show the list of free blocks. disk/reconcile uses the output of this to reconcile the list of used blocks with the list of free blocks.
.IP
.EX
disk/free tests/test.0/disk
.EE
.PP
Read two lists of block numbers and flag the common and missing blocks.
.IP
.EX
disk/reconcile -u <{disk/used tests/test.0/disk} \\
-F <{disk/free tests/test.0/disk} 32
.EE
.PP
Build the list of free blocks. This should match the contents of /adm/frees.
.IP
.EX
disk/unused <{disk/used test.0/disk} 32
.EE
.PP
Traverse the directory heirarchy and write out all the used block numbers.
.IP
.EX
disk/used tests/test.0/disk
.EE
.PP
Change the contents of /adm/frees.
.IP
.EX
disk/updatefrees tests/test.0/disk \\
<{disk/unused <{disk/used tests/test.0/disk} 32}
.EE
.PP
A sanity check that the file system is not corrupt by comparing that the unused blocks and free blocks match up. $nblocks is the total number of disk blocks. $disk is the disk.
.IP
.EX
diff <{disk/unused -l <{disk/used tests/test.0/disk} 32}} \\
<{disk/free tests/test.0/disk}
.EE
.SH SOURCE
.B /sys/src/cmd/mafs
.SH SEE ALSO
.IR mafs (4)
.br
M[a]fs - Plan 9 userspace file system
.SH SOURCE
.B /sys/src/cmd/mafs