return ret;
 }
 
-static int ocfs2_write_remove_suid(struct inode *inode)
+static int __ocfs2_write_remove_suid(struct inode *inode,
+                                    struct buffer_head *bh)
 {
        int ret;
-       struct buffer_head *bh = NULL;
-       struct ocfs2_inode_info *oi = OCFS2_I(inode);
        handle_t *handle;
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
        struct ocfs2_dinode *di;
 
        mlog_entry("(Inode %llu, mode 0%o)\n",
-                  (unsigned long long)oi->ip_blkno, inode->i_mode);
+                  (unsigned long long)OCFS2_I(inode)->ip_blkno, inode->i_mode);
 
        handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
        if (handle == NULL) {
                goto out;
        }
 
-       ret = ocfs2_read_block(osb, oi->ip_blkno, &bh, OCFS2_BH_CACHED, inode);
-       if (ret < 0) {
-               mlog_errno(ret);
-               goto out_trans;
-       }
-
        ret = ocfs2_journal_access(handle, inode, bh,
                                   OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret < 0) {
                mlog_errno(ret);
-               goto out_bh;
+               goto out_trans;
        }
 
        inode->i_mode &= ~S_ISUID;
        ret = ocfs2_journal_dirty(handle, bh);
        if (ret < 0)
                mlog_errno(ret);
-out_bh:
-       brelse(bh);
+
 out_trans:
        ocfs2_commit_trans(osb, handle);
 out:
        return ret;
 }
 
+static int ocfs2_write_remove_suid(struct inode *inode)
+{
+       int ret;
+       struct buffer_head *bh = NULL;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+
+       ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
+                              oi->ip_blkno, &bh, OCFS2_BH_CACHED, inode);
+       if (ret < 0) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ret =  __ocfs2_write_remove_suid(inode, bh);
+out:
+       brelse(bh);
+       return ret;
+}
+
 /*
  * Allocate enough extents to cover the region starting at byte offset
  * start for len bytes. Existing extents are skipped, any extents
        return ret;
 }
 
+/*
+ * Parts of this function taken from xfs_change_file_space()
+ */
+int ocfs2_change_file_space(struct file *file, unsigned int cmd,
+                           struct ocfs2_space_resv *sr)
+{
+       int ret;
+       s64 llen;
+       struct inode *inode = file->f_path.dentry->d_inode;
+       struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+       struct buffer_head *di_bh = NULL;
+       handle_t *handle;
+       unsigned long long max_off = ocfs2_max_file_offset(inode->i_sb->s_blocksize_bits);
+
+       if ((cmd == OCFS2_IOC_RESVSP || cmd == OCFS2_IOC_RESVSP64) &&
+           !ocfs2_writes_unwritten_extents(osb))
+               return -ENOTTY;
+       else if ((cmd == OCFS2_IOC_UNRESVSP || cmd == OCFS2_IOC_UNRESVSP64) &&
+                !ocfs2_sparse_alloc(osb))
+               return -ENOTTY;
+
+       if (!S_ISREG(inode->i_mode))
+               return -EINVAL;
+
+       if (!(file->f_mode & FMODE_WRITE))
+               return -EBADF;
+
+       if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
+               return -EROFS;
+
+       mutex_lock(&inode->i_mutex);
+
+       /*
+        * This prevents concurrent writes on other nodes
+        */
+       ret = ocfs2_rw_lock(inode, 1);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ret = ocfs2_meta_lock(inode, &di_bh, 1);
+       if (ret) {
+               mlog_errno(ret);
+               goto out_rw_unlock;
+       }
+
+       if (inode->i_flags & (S_IMMUTABLE|S_APPEND)) {
+               ret = -EPERM;
+               goto out_meta_unlock;
+       }
+
+       switch (sr->l_whence) {
+       case 0: /*SEEK_SET*/
+               break;
+       case 1: /*SEEK_CUR*/
+               sr->l_start += file->f_pos;
+               break;
+       case 2: /*SEEK_END*/
+               sr->l_start += i_size_read(inode);
+               break;
+       default:
+               ret = -EINVAL;
+               goto out_meta_unlock;
+       }
+       sr->l_whence = 0;
+
+       llen = sr->l_len > 0 ? sr->l_len - 1 : sr->l_len;
+
+       if (sr->l_start < 0
+           || sr->l_start > max_off
+           || (sr->l_start + llen) < 0
+           || (sr->l_start + llen) > max_off) {
+               ret = -EINVAL;
+               goto out_meta_unlock;
+       }
+
+       if (cmd == OCFS2_IOC_RESVSP || cmd == OCFS2_IOC_RESVSP64) {
+               if (sr->l_len <= 0) {
+                       ret = -EINVAL;
+                       goto out_meta_unlock;
+               }
+       }
+
+       if (should_remove_suid(file->f_path.dentry)) {
+               ret = __ocfs2_write_remove_suid(inode, di_bh);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out_meta_unlock;
+               }
+       }
+
+       down_write(&OCFS2_I(inode)->ip_alloc_sem);
+       switch (cmd) {
+       case OCFS2_IOC_RESVSP:
+       case OCFS2_IOC_RESVSP64:
+               /*
+                * This takes unsigned offsets, but the signed ones we
+                * pass have been checked against overflow above.
+                */
+               ret = ocfs2_allocate_unwritten_extents(inode, sr->l_start,
+                                                      sr->l_len);
+               break;
+       case OCFS2_IOC_UNRESVSP:
+       case OCFS2_IOC_UNRESVSP64:
+               ret = ocfs2_remove_inode_range(inode, di_bh, sr->l_start,
+                                              sr->l_len);
+               break;
+       default:
+               ret = -EINVAL;
+       }
+       up_write(&OCFS2_I(inode)->ip_alloc_sem);
+       if (ret) {
+               mlog_errno(ret);
+               goto out_meta_unlock;
+       }
+
+       /*
+        * We update c/mtime for these changes
+        */
+       handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
+       if (IS_ERR(handle)) {
+               ret = PTR_ERR(handle);
+               mlog_errno(ret);
+               goto out_meta_unlock;
+       }
+
+       inode->i_ctime = inode->i_mtime = CURRENT_TIME;
+       ret = ocfs2_mark_inode_dirty(handle, inode, di_bh);
+       if (ret < 0)
+               mlog_errno(ret);
+
+       ocfs2_commit_trans(osb, handle);
+
+out_meta_unlock:
+       brelse(di_bh);
+       ocfs2_meta_unlock(inode, 1);
+out_rw_unlock:
+       ocfs2_rw_unlock(inode, 1);
+
+       mutex_unlock(&inode->i_mutex);
+out:
+       return ret;
+}
+
 static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
                                         loff_t *ppos,
                                         size_t count,
 
 #define OCFS2_IOC32_GETFLAGS   _IOR('f', 1, int)
 #define OCFS2_IOC32_SETFLAGS   _IOW('f', 2, int)
 
+/*
+ * Space reservation / allocation / free ioctls and argument structure
+ * are designed to be compatible with XFS.
+ *
+ * ALLOCSP* and FREESP* are not and will never be supported, but are
+ * included here for completeness.
+ */
+struct ocfs2_space_resv {
+       __s16           l_type;
+       __s16           l_whence;
+       __s64           l_start;
+       __s64           l_len;          /* len == 0 means until end of file */
+       __s32           l_sysid;
+       __u32           l_pid;
+       __s32           l_pad[4];       /* reserve area                     */
+};
+
+#define OCFS2_IOC_ALLOCSP              _IOW ('X', 10, struct ocfs2_space_resv)
+#define OCFS2_IOC_FREESP               _IOW ('X', 11, struct ocfs2_space_resv)
+#define OCFS2_IOC_RESVSP               _IOW ('X', 40, struct ocfs2_space_resv)
+#define OCFS2_IOC_UNRESVSP     _IOW ('X', 41, struct ocfs2_space_resv)
+#define OCFS2_IOC_ALLOCSP64    _IOW ('X', 36, struct ocfs2_space_resv)
+#define OCFS2_IOC_FREESP64     _IOW ('X', 37, struct ocfs2_space_resv)
+#define OCFS2_IOC_RESVSP64     _IOW ('X', 42, struct ocfs2_space_resv)
+#define OCFS2_IOC_UNRESVSP64   _IOW ('X', 43, struct ocfs2_space_resv)
+
 /*
  * Journal Flags (ocfs2_dinode.id1.journal1.i_flags)
  */