[XFS] Combine the XFS and Linux inodes

To avoid issues with different lifecycles of XFS and Linux inodes, embedd
the linux inode inside the XFS inode. This means that the linux inode has
the same lifecycle as the XFS inode, even when it has been released by the
OS. XFS inodes don't live much longer than this (a short stint in reclaim
at most), so there isn't significant memory usage penalties here.

Version 3 o kill xfs_icount()

Version 2 o remove unused commented out code from xfs_iget(). o kill
useless cast in VFS_I()

SGI-PV: 988141

SGI-Modid: xfs-linux-melb:xfs-kern:32323a

Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 6fd20fc179a4..345b43a90eb5 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -236,7 +236,6 @@ typedef struct xfs_inode {
         /* Inode linking and identification information. */
         struct xfs_mount        *i_mount;       /* fs mount struct ptr */
         struct list_head        i_reclaim;      /* reclaim list */
-        struct inode            *i_vnode;       /* vnode backpointer */
         struct xfs_dquot        *i_udquot;      /* user dquot */
         struct xfs_dquot        *i_gdquot;      /* group dquot */
 
@@ -271,6 +270,10 @@ typedef struct xfs_inode {
         xfs_fsize_t             i_size;         /* in-memory size */
         xfs_fsize_t             i_new_size;     /* size when write completes */
         atomic_t                i_iocount;      /* outstanding I/O count */
+
+        /* VFS inode */
+        struct inode            i_vnode;        /* embedded VFS inode */
+
         /* Trace buffers per inode. */
 #ifdef XFS_INODE_TRACE
         struct ktrace           *i_trace;       /* general inode trace */
@@ -298,13 +301,13 @@ typedef struct xfs_inode {
 /* Convert from vfs inode to xfs inode */
 static inline struct xfs_inode *XFS_I(struct inode *inode)
 {
-        return (struct xfs_inode *)inode->i_private;
+        return container_of(inode, struct xfs_inode, i_vnode);
 }
 
 /* convert from xfs inode to vfs inode */
 static inline struct inode *VFS_I(struct xfs_inode *ip)
 {
-        return (struct inode *)ip->i_vnode;
+        return &ip->i_vnode;
 }
 
 /*