http://us3.samba.org/samba/docs/man/manpages-3/smb.conf.5.htmldfree command (S)
The dfree command setting should only be used on systems where a problem occurs with the internal disk space calculations. This has been known to happen with Ultrix, but may occur with other operating systems. The symptom that was seen was an error of "Abort Retry Ignore" at the end of each directory listing.
This setting allows the replacement of the internal routines to calculate the total disk space and amount available with an external routine. The example below gives a possible script that might fulfill this function.
In Samba version 3.0.21 this parameter has been changed to be a per-share parameter, and in addition the parameter dfree cache time was added to allow the output of this script to be cached for systems under heavy load.
The external program will be passed a single parameter indicating a directory in the filesystem being queried. This will typically consist of the string ./. The script should return two integers in ASCII. The first should be the total disk space in blocks, and the second should be the number of available blocks. An optional third return value can give the block size in bytes. The default blocksize is 1024 bytes.
Note: Your script should NOT be setuid or setgid and should be owned by (and writeable only by) root!
Where the script dfree (which must be made executable) could be:
#!/bin/sh
df $1 | tail -1 | awk '{print $(NF-4),$(NF-2)}'
or perhaps (on Sys V based systems):
#!/bin/sh
/usr/bin/df -k $1 | tail -1 | awk '{print $3" "$5}'
Note that you may have to replace the command names with full path names on some systems.
By default internal routines for determining the disk capacity and remaining space will be used.
No default
Example: dfree command = /usr/local/samba/bin/dfree
