Why l1_idFileSystem is answered by st.st_ex_dev?
jra at samba.org
Wed Oct 26 19:42:15 UTC 2016
On Wed, Oct 26, 2016 at 12:22:22PM +0000, withlog at yahoo.com wrote:
> Hi, everybody:
> I read the function smbd_do_qfsinfo. I found that in case SMB_INFO_ALLOCATION, there is following sentence:
> My question is why use st.st_ex_dev ? Actually, according to [MS-CIFS], it is the id of file system. If we call the function statfs, we will get the struct statfs *buf. In this struct, there is a "fsid_t f_fsid;". Why not use this f_fsid?
Well the id of the file system can mean
many things. Whist the server is up, the
device number serves to uniquely identify
the file system, so I don't see a problem
with st.st_ex_dev here.
Only if this number needs to be preserved
across client sessions would the file system
id on disk be useful (and do all UNIXes have
such a concept ?).
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