CephFS, quotas and rename()
Ceph like always at its best without proper documentation. The best documentation for Ceph is just reading the source code. This case is not an exception. Take this simple example:
#include <stdio.h>
int main()
{
int rc = -1;
char *renamefrom = "/home/003/10003/test1.jpg";
char *name = "/home/003/10003/public_html/test.jpg";
if (rc = rename(renamefrom, name) < 0) {
printf("%d\n", rc);
}
return 0;
}
It tries to rename file between different directories. It doesn’t work, such wow.
ceph-fuse client code says:
int Client::_rename(Inode *fromdir, const char *fromname, Inode *todir, const char *toname, int uid, int gid)
...
if (cct->_conf->client_quota &&
fromdir != todir &&
(fromdir->quota.is_enable() ||
todir->quota.is_enable() ||
get_quota_root(fromdir) != get_quota_root(todir))) {
return -EXDEV;
}
...
Ceph-fuse handles EXDEV strictly, thus it doesn’t allow to rename file between different directories if quota is enabled for one of them or they should be equal.