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authorMiklos Szeredi <mszeredi@redhat.com>2020-11-12 11:31:55 +0100
committerMiklos Szeredi <mszeredi@redhat.com>2020-11-12 11:31:55 +0100
commit58afaf5d605f091abf7491774e34fa29d4a1994c (patch)
tree0012d0a4e668d469db013f5a8829376f771d20a2 /Documentation/filesystems/overlayfs.rst
parentovl: introduce new "uuid=off" option for inodes index feature (diff)
downloadlinux-58afaf5d605f091abf7491774e34fa29d4a1994c.tar.xz
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ovl: doc clarification
Documentation says "The lower filesystem can be any filesystem supported by Linux". However, this is not the case, as Linux supports vfat and vfat doesn't work as a lower filesystem Reported-by: nerdopolis <bluescreen_avenger@verizon.net> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst
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@@ -97,11 +97,13 @@ directory trees to be in the same filesystem and there is no
requirement that the root of a filesystem be given for either upper or
lower.
-The lower filesystem can be any filesystem supported by Linux and does
-not need to be writable. The lower filesystem can even be another
-overlayfs. The upper filesystem will normally be writable and if it
-is it must support the creation of trusted.* extended attributes, and
-must provide valid d_type in readdir responses, so NFS is not suitable.
+A wide range of filesystems supported by Linux can be the lower filesystem,
+but not all filesystems that are mountable by Linux have the features
+needed for OverlayFS to work. The lower filesystem does not need to be
+writable. The lower filesystem can even be another overlayfs. The upper
+filesystem will normally be writable and if it is it must support the
+creation of trusted.* extended attributes, and must provide valid d_type in
+readdir responses, so NFS is not suitable.
A read-only overlay of two read-only filesystems may use any
filesystem type.