-
My file system sematics program
-presented
-a few days ago is very useful to verify that a file system can
-work as a unix home directory,and today I had to extend it a bit. I'm
-looking into alternatives for home directory access here at the
-University of Oslo, and one of the options is sshfs. My friend
-Finn-Arne mentioned a while back that they had used sshfs with Debian
-Edu, but stopped because of problems. I asked today what the problems
-where, and he mentioned that sshfs failed to handle umask properly.
-Trying to detect the problem I wrote this addition to my fs testing
-script:
-
-
-mode_t touch_get_mode(const char *name, mode_t mode) {
- mode_t retval = 0;
- int fd = open(name, O_RDWR|O_CREAT|O_LARGEFILE, mode);
- if (-1 != fd) {
- unlink(name);
- struct stat statbuf;
- if (-1 != fstat(fd, &statbuf)) {
- retval = statbuf.st_mode & 0x1ff;
- }
- close(fd);
- }
- return retval;
-}
-
-/* Try to detect problem discovered using sshfs */
-int test_umask(void) {
- printf("info: testing umask effect on file creation\n");
-
- mode_t orig_umask = umask(000);
- mode_t newmode;
- if (0666 != (newmode = touch_get_mode("foobar", 0666))) {
- printf(" error: Wrong file mode %o when creating using mode 666 and umask 000\n",
- newmode);
- }
- umask(007);
- if (0660 != (newmode = touch_get_mode("foobar", 0666))) {
- printf(" error: Wrong file mode %o when creating using mode 666 and umask 007\n",
- newmode);
- }
-
- umask (orig_umask);
- return 0;
-}
-
-int main(int argc, char **argv) {
- [...]
- test_umask();
- return 0;
-}
-
-
-
Sure enough. On NFS to a netapp, I get this result:
-
-
-Testing POSIX/Unix sematics on file system
-info: testing symlink creation
-info: testing subdirectory creation
-info: testing fcntl locking
- Read-locking 1 byte from 1073741824
- Read-locking 510 byte from 1073741826
- Unlocking 1 byte from 1073741824
- Write-locking 1 byte from 1073741824
- Write-locking 510 byte from 1073741826
- Unlocking 2 byte from 1073741824
-info: testing umask effect on file creation
-
-
-
When mounting the same directory using sshfs, I get this
-result:
-
-
-Testing POSIX/Unix sematics on file system
-info: testing symlink creation
-info: testing subdirectory creation
-info: testing fcntl locking
- Read-locking 1 byte from 1073741824
- Read-locking 510 byte from 1073741826
- Unlocking 1 byte from 1073741824
- Write-locking 1 byte from 1073741824
- Write-locking 510 byte from 1073741826
- Unlocking 2 byte from 1073741824
-info: testing umask effect on file creation
- error: Wrong file mode 644 when creating using mode 666 and umask 000
- error: Wrong file mode 640 when creating using mode 666 and umask 007
-
-
-
So, I can conclude that sshfs is better than smb to a Netapp or a
-Windows server, but not good enough to be used as a home
-directory.
-
-
Update 2010-08-26: Reported the issue in
-BTS report #594498
-
-
Update 2010-08-27: Michael Gebetsroither report that he found the
-script so useful that he created a GIT repository and stored it in
-http://github.com/gebi/fs-test.
-
