DESCRIPTION OF THE PROBLEM Some users are accustomed to using shared folders in Windows with a comma in the name, for example: "//server3/Block 3,4". When they try to migrate to Linux, they cannot mount such paths. An example of the line generated by "mount.cifs" for the kernel when mounting "//server3/Block 3,4": "ip=10.0.2.212,unc=\\server3\Block 3,4,iocharset=utf8,user=user1,domain=AD" Accordingly, due to the extra comma, we have an error: "Sep 7 21:57:18 S1 kernel: [ 795.604821] CIFS: Unknown mount option "4"" DOCUMENTATION https://www.kernel.org/doc/html/latest/admin-guide/cifs/usage.html The "sep" parameter is described here to specify a new delimiter instead of a comma. I quote: "sep if first mount option (after the -o), overrides the comma as the separator between the mount parms. e.g.: -o user=myname,password=mypassword,domain=mydom could be passed instead with period as the separator by: -o sep=.user=myname.password=mypassword.domain=mydom this might be useful when comma is contained within username or password or domain." RESEARCH WORK I looked at the "mount.cifs" code. There is no provision for the use of a comma by the user, since the comma is used to form the parameter string to the kernel (man 2 mount). This line can be seen by adding the "--verbose" flag to the mount. "mount.cifs --help" lists "sep" as a possible option, but does not implement it in the code and does not describe it in "man 8 mount.cifs". I looked at the "pam-mount" code - the mount options are assembled with a wildcard comma. The result is a text line: "mount -t cifs ...". The handling of options in the "mount" utility is based on the "libmount" library, which is hardcoded to use only a comma as a delimiter. I tried to mount "//server3/Block 3,4" with my own program (man 2 mount) by specifying "sep=!" - successfully. SOLUTION It would be nice if we add in "mount.cifs", in "mount" utility and in "pam-mount" the ability to set a custom mount option separator. In other words, we need to implement the already documented "sep" option. 1. For "mount.cifs" I did it in: https://github.com/dmitry-telegin/cifs-utils in branch "custom_option_separator". Commit: https://github.com/dmitry-telegin/cifs-utils/commit/04325b842a82edf655a14174e763bc0b2a6870e1 2. For "mount" utility I did it in: https://github.com/dmitry-telegin/util-linux in branch "custom_option_separator". Commit: https://github.com/dmitry-telegin/util-linux/commit/5e0ecd2498edae0bf0bcab4ba6a68a9803b34ccf 3. For "pam-mount" I did it in: https://sourceforge.net/u/dmitry-t/pam-mount/ci/master/tree/ in branch "custom_option_separator". Commit: https://sourceforge.net/u/dmitry-t/pam-mount/ci/9860f9234977f1110230482b5d87bdcb8bc6ce03/ I checked the work on the Linux 5.10 kernel. -- Dmitry Telegin
