[GFS2] inode_diet: Replace inode.u.generic_ip with inode.i_private (gfs)

The following patches reduce the size of the VFS inode structure by 28 bytes
on a UP x86.  (It would be more on an x86_64 system).  This is a 10% reduction
in the inode size on a UP kernel that is configured in a production mode
(i.e., with no spinlock or other debugging functions enabled; if you want to
save memory taken up by in-core inodes, the first thing you should do is
disable the debugging options; they are responsible for a huge amount of bloat
in the VFS inode structure).

This patch:

The filesystem or device-specific pointer in the inode is inside a union,
which is pretty pointless given that all 30+ users of this field have been
using the void pointer.  Get rid of the union and rename it to i_private, with
a comment to explain who is allowed to use the void pointer.  This is just a
cleanup, but it allows us to reuse the union 'u' for something something where
the union will actually be used.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

diff --git a/fs/dlm/debug_fs.c b/fs/dlm/debug_fs.c
index 9c3aeddc86677589b2efe00b42cb3f77767e41c4..ca94a837a5bba1d92b0478ecfced67c2538aab89 100644 (file)
--- a/fs/dlm/debug_fs.c
+++ b/fs/dlm/debug_fs.c
@@ -282,7 +282,7 @@ static int rsb_open(struct inode *inode, struct file *file)
                return ret;
 
        seq = file->private_data;
-       seq->private = inode->u.generic_ip;
+       seq->private = inode->i_private;
 
        return 0;
 }
@@ -301,7 +301,7 @@ static struct file_operations rsb_fops = {
 
 static int waiters_open(struct inode *inode, struct file *file)
 {
-       file->private_data = inode->u.generic_ip;
+       file->private_data = inode->i_private;
        return 0;
 }
 

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index ac9535be304f070405ec89bb138590801979640e..784d145058cb43ae3cda2611b9a64eb5302ec754 100644 (file)
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -160,7 +160,7 @@ struct inode *gfs2_inode_lookup(struct super_block *sb, struct gfs2_inum *inum,
        if (inode->i_state & I_NEW) {
                struct gfs2_sbd *sdp = GFS2_SB(inode);
                umode_t mode = DT2IF(type);
-               inode->u.generic_ip = ip;
+               inode->i_private = ip;
                inode->i_mode = mode;
 
                if (S_ISREG(mode)) {

diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index d3708af0a4d1c77c20cdb8089bb9d6f5d5bf1386..731799153187b301b701e47f38fa4ca771d9f9b4 100644 (file)
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -78,7 +78,7 @@ struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
                mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
                aspace->i_mapping->a_ops = &aspace_aops;
                aspace->i_size = ~0ULL;
-               aspace->u.generic_ip = NULL;
+               aspace->i_private = NULL;
                insert_inode_hash(aspace);
        }
        return aspace;

diff --git a/fs/gfs2/ops_super.c b/fs/gfs2/ops_super.c
index 8cfda64521393fd47df6b48b41967e6b92d060e5..06f06f7773d044f01ed58e5eaab893fc1051fc15 100644 (file)
--- a/fs/gfs2/ops_super.c
+++ b/fs/gfs2/ops_super.c
@@ -53,7 +53,7 @@ static int gfs2_write_inode(struct inode *inode, int sync)
        struct gfs2_inode *ip = GFS2_I(inode);
 
        /* Check this is a "normal" inode */
-       if (inode->u.generic_ip) {
+       if (inode->i_private) {
                if (current->flags & PF_MEMALLOC)
                        return 0;
                if (sync)
@@ -280,7 +280,7 @@ static void gfs2_clear_inode(struct inode *inode)
         * serves to contain an address space (see rgrp.c, meta_io.c)
         * which therefore doesn't have its own glocks.
         */
-       if (inode->u.generic_ip) {
+       if (inode->i_private) {
                struct gfs2_inode *ip = GFS2_I(inode);
                gfs2_glock_inode_squish(inode);
                gfs2_assert(inode->i_sb->s_fs_info, ip->i_gl->gl_state == LM_ST_UNLOCKED);
@@ -381,7 +381,7 @@ static void gfs2_delete_inode(struct inode *inode)
        struct gfs2_holder gh;
        int error;
 
-       if (!inode->u.generic_ip)
+       if (!inode->i_private)
                goto out;
 
        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, LM_FLAG_TRY_1CB | GL_NOCACHE, &gh);