[RFC 06/17] xfs: (parent ptr) add parent pointer support to inode v5

[Mark Tinguely <tinguely@xxxxxxx>]

Add the fields to inode v5 to track the parent inode number
and this entry's offset in the parent inode leaving the entries
in disk format.

---
 fs/xfs/xfs_dinode.h     |    4 +++-
 fs/xfs/xfs_inode_buf.c  |    6 ++++++
 fs/xfs/xfs_log_format.h |    4 +++-
 3 files changed, 12 insertions(+), 2 deletions(-)

Index: b/fs/xfs/xfs_dinode.h
===================================================================
--- a/fs/xfs/xfs_dinode.h
+++ b/fs/xfs/xfs_dinode.h
@@ -79,7 +79,9 @@ typedef struct xfs_dinode {
        __be64          di_changecount; /* number of attribute changes */
        __be64          di_lsn;         /* flush sequence */
        __be64          di_flags2;      /* more random flags */
-       __u8            di_pad2[16];    /* more padding for future expansion */
+       __be64          di_parent;      /* inode of parent directory */
+       __be32          di_poffset;     /* offset into parent directory */
+       __u8            di_pad2[4];     /* more padding for future expansion */
 
        /* fields only written to during inode creation */
        xfs_timestamp_t di_crtime;      /* time created */
Index: b/fs/xfs/xfs_inode_buf.c
===================================================================
--- a/fs/xfs/xfs_inode_buf.c
+++ b/fs/xfs/xfs_inode_buf.c
@@ -238,6 +238,9 @@ xfs_dinode_from_disk(
                to->di_lsn = be64_to_cpu(from->di_lsn);
                memcpy(to->di_pad2, from->di_pad2, sizeof(to->di_pad2));
                uuid_copy(&to->di_uuid, &from->di_uuid);
+               /* parent pointer information is left in disk order */
+               to->di_parent = from->di_parent;
+               to->di_poffset = from->di_poffset;
        }
 }
 
@@ -285,6 +288,9 @@ xfs_dinode_to_disk(
                memcpy(to->di_pad2, from->di_pad2, sizeof(to->di_pad2));
                uuid_copy(&to->di_uuid, &from->di_uuid);
                to->di_flushiter = 0;
+               /* parent pointer information is in disk order */
+               to->di_parent = from->di_parent;
+               to->di_poffset = from->di_poffset;
        } else {
                to->di_flushiter = cpu_to_be16(from->di_flushiter);
        }
Index: b/fs/xfs/xfs_log_format.h
===================================================================
--- a/fs/xfs/xfs_log_format.h
+++ b/fs/xfs/xfs_log_format.h
@@ -399,7 +399,9 @@ typedef struct xfs_icdinode {
        __uint64_t      di_changecount; /* number of attribute changes */
        xfs_lsn_t       di_lsn;         /* flush sequence */
        __uint64_t      di_flags2;      /* more random flags */
-       __uint8_t       di_pad2[16];    /* more padding for future expansion */
+       __uint64_t      di_parent;      /* inode of parent directory */
+       __uint32_t      di_poffset;     /* offset into parent directory */
+       __uint8_t       di_pad2[4];     /* more padding for future expansion */
 
        /* fields only written to during inode creation */
        xfs_ictimestamp_t di_crtime;    /* time created */