Add Linux namespace delegation support

This allows ZFS datasets to be delegated to a user/mount namespace
Within that namespace, only the delegated datasets are visible
Works very similarly to Zones/Jailes on other ZFS OSes

As a user:
```
 $ unshare -Um
 $ zfs list
no datasets available
 $ echo $$
1234
```

As root:
```
 # zfs list
NAME                            ZONED  MOUNTPOINT
containers                      off    /containers
containers/host                 off    /containers/host
containers/host/child           off    /containers/host/child
containers/host/child/gchild    off    /containers/host/child/gchild
containers/unpriv               on     /unpriv
containers/unpriv/child         on     /unpriv/child
containers/unpriv/child/gchild  on     /unpriv/child/gchild

 # zfs zone /proc/1234/ns/user containers/unpriv
```

Back to the user namespace:
```
 $ zfs list
NAME                             USED  AVAIL     REFER  MOUNTPOINT
containers                       129M  47.8G       24K  /containers
containers/unpriv                128M  47.8G       24K  /unpriv
containers/unpriv/child          128M  47.8G      128M  /unpriv/child
```

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Will Andrews <will.andrews@klarasystems.com>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Mateusz Piotrowski <mateusz.piotrowski@klarasystems.com>
Co-authored-by: Allan Jude <allan@klarasystems.com>
Co-authored-by: Mateusz Piotrowski <mateusz.piotrowski@klarasystems.com>
Sponsored-by: Buddy <https://buddy.works>
Closes #12263
This commit is contained in:
Will Andrews
2021-02-21 10:19:43 -06:00
committed by Brian Behlendorf
parent a1aa8f14c8
commit 4ed5e25074
33 changed files with 1166 additions and 15 deletions
+10
View File
@@ -150,6 +150,7 @@ typedef enum zfs_error {
EZFS_EXPORT_IN_PROGRESS, /* currently exporting the pool */
EZFS_REBUILDING, /* resilvering (sequential reconstrution) */
EZFS_VDEV_NOTSUP, /* ops not supported for this type of vdev */
EZFS_NOT_USER_NAMESPACE, /* a file is not a user namespace */
EZFS_UNKNOWN
} zfs_error_t;
@@ -979,6 +980,15 @@ _LIBZFS_H int zpool_nextboot(libzfs_handle_t *, uint64_t, uint64_t,
#endif /* __FreeBSD__ */
#ifdef __linux__
/*
* Add or delete the given filesystem to/from the given user namespace.
*/
_LIBZFS_H int zfs_userns(zfs_handle_t *zhp, const char *nspath, int attach);
#endif
#ifdef __cplusplus
}
#endif