ext4.5: document the stable_inodes feature

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/misc/ext4.5.in b/misc/ext4.5.in
index 1db61a5..90bc4f8 100644 (file)
--- a/misc/ext4.5.in
+++ b/misc/ext4.5.in
@@ -299,6 +299,20 @@ feature is essentially a more extreme version of sparse_super and is
 designed to allow a much larger percentage of the disk to have
 contiguous blocks available for data files.
 .TP
+.B stable_inodes
+.br
+Marks the filesystem's inode numbers and UUID as stable.
+.BR resize2fs (8)
+will not allow shrinking a filesystem with this feature, nor
+will
+.BR tune2fs (8)
+allow changing its UUID.  This feature allows the use of specialized encryption
+settings that make use of the inode numbers and UUID.  Note that the
+.B encrypt
+feature still needs to be enabled separately.
+.B stable_inodes
+is a "compat" feature, so old kernels will allow it.
+.TP
 .B uninit_bg
 .br
 This ext4 file system feature indicates that the block group descriptors
@@ -788,6 +802,8 @@ ext4, 4.13
 ext4, 5.2
 .IP "\fBverity\fR" 2i
 ext4, 5.4
+.IP "\fBstable_inodes\fR" 2i
+ext4, 5.5
 .SH SEE ALSO
 .BR mke2fs (8),
 .BR mke2fs.conf (5),