reiserfs: shrink superblock if no xattrs

This makes in-core superblock fit into one cacheline here.

Before:
    struct dentry *            xattr_root;           /*   124     4 */
    /* --- cacheline 1 boundary (128 bytes) --- */
    struct rw_semaphore        xattr_dir_sem;        /*   128    12 */
    int                        j_errno;              /*   140     4 */
    }; /* size: 144, cachelines: 2 */
       /* sum members: 142, holes: 1, sum holes: 2 */
       /* last cacheline: 16 bytes */

After:
    int                        j_errno;              /*   124     4 */
    /* --- cacheline 1 boundary (128 bytes) --- */
    }; /* size: 128, cachelines: 1 */
       /* sum members: 126, holes: 1, sum holes: 2 */

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: <reiserfs-dev@namesys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 6 insertions, 3 deletions

diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
index 7054aaef0493..5c58b419f4ee 100644
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -433,12 +433,13 @@ int remove_save_link(struct inode *inode, int truncate)
 static void reiserfs_kill_sb(struct super_block *s)
 {
         if (REISERFS_SB(s)) {
+#ifdef CONFIG_REISERFS_FS_XATTR
                 if (REISERFS_SB(s)->xattr_root) {
                         d_invalidate(REISERFS_SB(s)->xattr_root);
                         dput(REISERFS_SB(s)->xattr_root);
                         REISERFS_SB(s)->xattr_root = NULL;
                 }
-
+#endif
                 if (REISERFS_SB(s)->priv_root) {
                         d_invalidate(REISERFS_SB(s)->priv_root);
                         dput(REISERFS_SB(s)->priv_root);
@@ -1562,9 +1563,10 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
         REISERFS_SB(s)->s_alloc_options.preallocmin = 0;
         /* Preallocate by 16 blocks (17-1) at once */
         REISERFS_SB(s)->s_alloc_options.preallocsize = 17;
+#ifdef CONFIG_REISERFS_FS_XATTR
         /* Initialize the rwsem for xattr dir */
         init_rwsem(&REISERFS_SB(s)->xattr_dir_sem);
-
+#endif
         /* setup default block allocator options */
         reiserfs_init_alloc_options(s);
 
diff --git a/include/linux/reiserfs_fs_sb.h b/include/linux/reiserfs_fs_sb.h
index 3a28742d86f9..1e5488ede037 100644
--- a/include/linux/reiserfs_fs_sb.h
+++ b/include/linux/reiserfs_fs_sb.h
@@ -401,9 +401,10 @@ struct reiserfs_sb_info {
         int reserved_blocks;    /* amount of blocks reserved for further allocations */
         spinlock_t bitmap_lock; /* this lock on now only used to protect reserved_blocks variable */
         struct dentry *priv_root;       /* root of /.reiserfs_priv */
+#ifdef CONFIG_REISERFS_FS_XATTR
         struct dentry *xattr_root;      /* root of /.reiserfs_priv/.xa */
         struct rw_semaphore xattr_dir_sem;
-
+#endif
         int j_errno;
 #ifdef CONFIG_QUOTA
         char *s_qf_names[MAXQUOTAS];