[lustre-devel] [PATCH 01/22] ext4: add i_fs_version
James Simmons
jsimmons at infradead.org
Mon Jul 22 17:07:38 PDT 2019
> > From: James Simmons <uja.ornl at yahoo.com>
> >
> > Add inode version field that osd-ldiskfs uses.
>
> We need more words here. What is i_fs_version used for?
>
> (I'll probably find out as I keep reading, but I need to know
> the intention first, or I cannot properly review the patches
> that make use of it.
> )
Sadly these patches don't contain much in terms of why they exist.
I did some digging and it seems at one time Lustre did use the
i_version field directly for it recovery process. It seems ext4 stomps
on its i_version independently of lustre so it can't be trusted in
use of recovery.
> NeilBrown
>
>
> >
> > Signed-off-by: James Simmons <uja.ornl at yahoo.com>
> > ---
> > fs/ext4/ext4.h | 2 ++
> > fs/ext4/ialloc.c | 1 +
> > fs/ext4/inode.c | 4 ++--
> > 3 files changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> > index 1cb6785..8abbcab 100644
> > --- a/fs/ext4/ext4.h
> > +++ b/fs/ext4/ext4.h
> > @@ -1063,6 +1063,8 @@ struct ext4_inode_info {
> > struct dquot *i_dquot[MAXQUOTAS];
> > #endif
> >
> > + u64 i_fs_version;
> > +
> > /* Precomputed uuid+inum+igen checksum for seeding inode checksums */
> > __u32 i_csum_seed;
> >
> > diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> > index 764ff4c..09ae4a4 100644
> > --- a/fs/ext4/ialloc.c
> > +++ b/fs/ext4/ialloc.c
> > @@ -1100,6 +1100,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
> > ei->i_dtime = 0;
> > ei->i_block_group = group;
> > ei->i_last_alloc_group = ~0;
> > + ei->i_fs_version = 0;
> >
> > ext4_set_inode_flags(inode);
> > if (IS_DIRSYNC(inode))
> > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> > index c7f77c6..6e66175 100644
> > --- a/fs/ext4/inode.c
> > +++ b/fs/ext4/inode.c
> > @@ -4806,14 +4806,14 @@ static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
> > if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
> > inode_set_iversion_raw(inode, val);
> > else
> > - inode_set_iversion_queried(inode, val);
> > + EXT4_I(inode)->i_fs_version = val;
> > }
> > static inline u64 ext4_inode_peek_iversion(const struct inode *inode)
> > {
> > if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
> > return inode_peek_iversion_raw(inode);
> > else
> > - return inode_peek_iversion(inode);
> > + return EXT4_I(inode)->i_fs_version;
> > }
> >
> > struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
> > --
> > 1.8.3.1
>
More information about the lustre-devel
mailing list