On Jul 10, 2007 22:40 -0700, Andrew Morton wrote:
> On Sun, 01 Jul 2007 03:38:18 -0400 Mingming Cao <[EMAIL PROTECTED]> wrote:
> > A EXT4_FEATURE_RO_COMPAT_DIR_NLINK flag has been added and it is set if
> > the subdir count for any directory crosses 65000.
>
> Would I be correct in assuming that a later fsck will clear
> EXT4_FEATURE_RO_COMPAT_DIR_NLINK if there are no longer any >65000 subdir
> directories?
Correct.
> If so, that is worth a mention in the changelog, perhaps?
>
> Please remind us what is the behaviour of an RO_COMPAT flag? It means that
> old ext4, ext3 and ext2 can only mount this fs read-only, yes?
Also correct. The COMPAT flag behaviour is described in detail in
Documentation/filesystems/ext[234].txt
> > +static inline void ext4_inc_count(handle_t *handle, struct inode *inode)
> > +{
> > + inc_nlink(inode);
> > + if (is_dx(inode) && inode->i_nlink > 1) {
> > + /* limit is 16-bit i_links_count */
> > + if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) {
> > + inode->i_nlink = 1;
> > + EXT4_SET_RO_COMPAT_FEATURE(inode->i_sb,
> > + EXT4_FEATURE_RO_COMPAT_DIR_NLINK);
> > + }
> > + }
> > +}
>
> Why do we set EXT4_FEATURE_RO_COMPAT_DIR_NLINK if i_nlink==2?
Because that means it was previously 1 (inc_nlink() was already called).
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
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