Documentation/filesystems/sharedsubtree.rst

33 Shared subtree provides four different flavors of mounts; struct vfsmount to be
60 	and the contents of both the mounts remain identical.
89 	All slave mounts have a master mount which is a shared.
182 	B) A process wants its mounts invisible to any other process, but
183 	still be able to see the other system mounts.
197 		Hence forth any mounts within the /myprivatetree done by the
198 		process will not show up in any other namespace. However mounts
208 		The above semantics allows a way to share mounts across
264 	(1) Shared mounts
276 		/mnt or /tmp reflect in all the other mounts of its peer
280 	(2) Slave mounts
388 	are created and mounted at the dentry 'b' on all mounts where 'B'
397 	are created and mounted at the dentry 'b' on all mounts where 'B'
398 	propagates to. A new propagation tree is set containing all new mounts
404 	'C' is mounted on mount 'B' at dentry 'b'. Also new mounts 'C1', 'C2',
405 	'C3' ... are created and mounted at the dentry 'b' on all mounts where
406 	'B' propagates to. A new propagation tree containing the new mounts
427 	slave mount of 'Z'. In other words 'A' and 'C' are both slave mounts of
438 	replicates all the mounts in the tree belonging to the specified mount.
439 	Rbind mount is bind mount applied to all the mounts in the tree.
441 	If the source tree that is rbind has some unbindable mounts,
502 	mounted on mount 'B' at dentry 'b'.  Also new mounts 'A1', 'A2'...'An'
503 	are created and mounted at dentry 'b' on all mounts that receive
506 	contains all the new mounts 'A1', 'A2'...  'An'.  And this new
512 	are created and mounted at dentry 'b' on all mounts that receive
515 	'B'. This new propagation tree contains all the new mounts 'A1',
519 	mount 'A' is mounted on mount 'B' at dentry 'b'.  Also new mounts 'A1',
520 	'A2'... 'An' are created and mounted at dentry 'b' on all mounts that
523 	tree contains all the new mounts 'A1', 'A2'...  'An'.  And this new
530 	create new mounts that get mounted on the mounts that receive
570 	If mount 'B' is shared, then all most-recently-mounted mounts at dentry
571 	'b' on mounts that receive propagation from mount 'B' and does not have
572 	sub-mounts within them are unmounted.
574 	Example: Let's say 'B1', 'B2', 'B3' are shared mounts that propagate to
583 	if 'C1' is unmounted, all the mounts that are most-recently-mounted on
584 	'B1' and on the mounts that 'B1' propagates-to are unmounted.
591 	If any of 'C2' or 'C3' has some child mounts, then that mount is not
592 	unmounted, but all other mounts are unmounted. However if 'C1' is told
593 	to be unmounted and 'C1' has some sub-mounts, the umount operation is
598 	A cloned namespace contains all the mounts as that of the parent
601 	Let's say 'A' and 'B' are the corresponding mounts in the parent and the
682 		unmounted or moved. Bind mounts continue to exist even if the
696 		if one rbind mounts a tree within the same subtree 'n' times
697 		the number of mounts created is an exponential function of 'n'.
699 		mounts. Here is an example.
774 		mounts than what we really needed in the first place.
777 		out the unneeded mounts. But there is a better solution.
778 		Unclonable mounts come in handy here.
863 		links all the mounts to which this vfsmount propagates
898 	mounts as a conceptual entity called 'pnode', it becomes a tree]::
910 	other.   'A' has got 3 slave mounts 'E' 'F' and 'G' 'C' has got 2 slave
911 	mounts 'J' and 'K'  and  'D' has got two slave mounts 'H' and 'I'.
966 		   	be attached to each of the mounts that receive
970 		   c) Link all the new mounts to form a propagation tree that
975 		   propagation trees; where 'n' is the number of mounts in the
979 		   the number of mounts to which the destination mount
986 		destination mounts.