On Fri, Jul 21, 2017 at 04:49:27PM -0600, Andreas Dilger wrote: > The dir_nlink feature has been enabled by default for new ext4 > filesystems since e2fsprogs-1.41 in 2008, and was automatically > enabled by the kernel for older ext4 filesystems since the > dir_nlink feature was added with ext4 in kernel 2.6.28+ when > the subdirectory count exceeded EXT4_LINK_MAX. > > We shouldn't really be enabling filesystem features automatically, > as this prevents the administrator from disabling the feature at > format time, or via tune2fs. This should not affect many users by > this point, but allows limiting subdirectory counts to those that > can strictly fit into i_links_count rather than using "1" to > indicate that the number of links on the directory is not tracked. > This avoids a bug in glibc fts_read() that incorrectly optimizes > the directory traversal for such directories. > > This also addresses a minor bug in ext4_inc_count() where i_nlinks > was wrapped at (EXT4_LINK_MAX - 1) links rather than allowing the > full EXT4_LINK_MAX links on the parent directory (including "." > and "..") before storing i_links_count = 1. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=196405 > Signed-off-by: Andreas Dilger <adilger@xxxxxxxxx> Thanks, applied. - Ted
