Commit 60b86642 authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
Browse files

ovl: update documentation of inodes index feature 



Document that inode index feature solves breaking hard links on
copy up.

Simplify Kconfig backward compatibility disclaimer.

Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 05122443

Documentation/filesystems/overlayfs.txt

+3 −3
Original line number Diff line number Diff line
@@ -281,9 +281,9 @@ filesystem, so both st_dev and st_ino of the file may change. 


Any open files referring to this inode will access the old data.



If a file with multiple hard links is copied up, then this will

"break" the link.  Changes will not be propagated to other names

referring to the same inode.

Unless "inode index" feature is enabled, if a file with multiple hard

links is copied up, then this will "break" the link.  Changes will not be

propagated to other names referring to the same inode.



Unless "redirect_dir" feature is enabled, rename(2) on a lower or merged

directory will fail with EXDEV.

fs/overlayfs/Kconfig

+3 −6
Original line number Diff line number Diff line
@@ -47,9 +47,6 @@ config OVERLAY_FS_INDEX 
	  The inodes index feature prevents breaking of lower hardlinks on copy

	  up.



	  Note, that the inodes index feature is read-only backward compatible.

	  That is, mounting an overlay which has an index dir on a kernel that

	  doesn't support this feature read-only, will not have any negative

	  outcomes.  However, mounting the same overlay with an old kernel

	  read-write and then mounting it again with a new kernel, will have

	  unexpected results.
 
	  Note, that the inodes index feature is not backward compatible.

	  That is, mounting an overlay which has an inodes index on a kernel

	  that doesn't support this feature will have unexpected results.

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