[PATCH] vfs_shadow_copy2: add snapsharepath parameter
Uri Simchoni
uri at samba.org
Fri Jan 22 10:08:35 UTC 2016
On 01/21/2016 10:44 PM, Michael Adam wrote:
> I don't see yet that the snapsharepath really gains anything. Will
> follow up with details. Michael
The use case is as follows:
In the original volume we have:
/mount/
+dir1
|
+dir2/
+subdir
And we have 2 shares:
[share1]
path = /mount/dir1
[share2]
path = /mount/dir2/subdir
Now suppose we have a backup system that backs up not the whole volume,
just the shares, and exposes snapshots to the user according to the
logical structure as follows (this is the file-system view of the
snapshots):
/snapshots/
+ at GMT-XXX/
| +share1
| |
| +share2
|
+ at GMT-YYY/
+share1
|
+share2
In that case the existing shadow_copy2 parameters would not suffice, but
snapsharepath (the relative path of the share inside the snapshot) would
do it.
I know of no FOSS project that would benefit from this but at Ctera
that's the way our snapshots are laid out.
Internally at vfs_shadow_copy2, the code uses rel_connectpath to find
the share inside the snapshot, so adding this parameter (which
essentially externalizes rel_connectpath) is a relatively small change.
Functionally, snapsharepath is a super-set of basedir, but the advantage
of basedir is that you can define it only once in [global] in some cases.
Thanks,
Uri.
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