On Tue, Jan 09, 2018 at 09:47:01AM -0500, Jeff Layton wrote: > From: Jeff Layton <jlayton@xxxxxxxxxx> > > This patch is based on top of the i_version rework that I'm flogging > upstream. It's just a cleanup of some nastiness I noticed while in there. > > This code uses the i_ctime and i_version fields to each store half of > a refcount. I suspect it was done this way long ago when the i_version Way long ago == 2017-06-22 :) The new 64k xattr value feature in ext4 uses hidden inodes to store attr values that don't fit in a single block. Since the inode can be shared by multiple xattr keys and isn't exported via NFS (I hope...), they use a 64-bit refcount mashed into i_ctime and i_version. That's what this gobbledygook is for. https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout#Large_Extended_Attribute_Values --D > field was a 32 bits, and was never changed when the field was converted > to a 64 bit value. > > Change the code to just store the refcount in the i_version field rather > than splitting it across both fields. > > Cc: David Howells <dhowells@xxxxxxxxxx> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > --- > fs/ext4/xattr.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c > index 63656dbafdc4..6ea78dd367ca 100644 > --- a/fs/ext4/xattr.c > +++ b/fs/ext4/xattr.c > @@ -294,14 +294,12 @@ ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size) > > static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode) > { > - return ((u64)ea_inode->i_ctime.tv_sec << 32) | > - (u32) inode_peek_iversion_raw(ea_inode); > + return inode_peek_iversion_raw(ea_inode); > } > > static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count) > { > - ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32); > - inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff); > + inode_set_iversion_raw(ea_inode, ref_count); > } > > static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode) > -- > 2.14.3 >
