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authorAmir Goldstein <amir73il@gmail.com>2018-01-11 00:15:21 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2018-01-24 12:20:02 +0300
commit60b866420ba7ae0b6a8d338f49be21c601d19064 (patch)
treeeacffe3aa31d206868938bc2d92149dcb738e125
parent051224438af21047b34160b1e0ad1c5af45fdace (diff)
downloadlinux-60b866420ba7ae0b6a8d338f49be21c601d19064.tar.xz
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: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
-rw-r--r--Documentation/filesystems/overlayfs.txt6
-rw-r--r--fs/overlayfs/Kconfig9
2 files changed, 6 insertions, 9 deletions
diff --git a/Documentation/filesystems/overlayfs.txt b/Documentation/filesystems/overlayfs.txt
index e6a5f4912b6d..213547cb6d36 100644
--- a/Documentation/filesystems/overlayfs.txt
+++ b/Documentation/filesystems/overlayfs.txt
@@ -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.
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig
index 5ac415466861..9eac01c3e21e 100644
--- a/fs/overlayfs/Kconfig
+++ b/fs/overlayfs/Kconfig
@@ -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.