[PATCH] cleanup xfs_vn_mknod

[Christoph Hellwig <hch@xxxxxx>]

 - use proper goto based unwinding instead of the current mess of
   multiple conditionals
 - rename ip to inode because that's the normal convention for Linux
   inodes while ip is the convention for xfs_inodes
 - remove unlikely checks for the default_acl - branches marked unlikely
   might lead to extreme branch bredictor slowdons if taken and for some
   workloads a default acl is quite common
 - properly indent the switch statements
 - remove xfs_has_fs_struct as nfsd has a fs_struct in any semi-recent
   kernel


Signed-off-by: Christoph Hellwig <hch@xxxxxx>

Index: linux-2.6-xfs/fs/xfs/linux-2.6/xfs_iops.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/linux-2.6/xfs_iops.c      2007-12-21 
07:25:06.000000000 +0100
+++ linux-2.6-xfs/fs/xfs/linux-2.6/xfs_iops.c   2007-12-21 07:33:25.000000000 
+0100
@@ -241,18 +241,6 @@ xfs_init_security(
        return error;
 }
 
-/*
- * Determine whether a process has a valid fs_struct (kernel daemons
- * like knfsd don't have an fs_struct).
- *
- * XXX(hch):  nfsd is broken, better fix it instead.
- */
-STATIC_INLINE int
-xfs_has_fs_struct(struct task_struct *task)
-{
-       return (task->fs != init_task.fs);
-}
-
 STATIC void
 xfs_cleanup_inode(
        struct inode    *dir,
@@ -284,7 +272,7 @@ xfs_vn_mknod(
        int             mode,
        dev_t           rdev)
 {
-       struct inode    *ip;
+       struct inode    *inode;
        bhv_vnode_t     *vp = NULL, *dvp = vn_from_inode(dir);
        xfs_acl_t       *default_acl = NULL;
        attrexists_t    test_default_acl = _ACL_DEFAULT_EXISTS;
@@ -297,7 +285,7 @@ xfs_vn_mknod(
        if (unlikely(!sysv_valid_dev(rdev) || MAJOR(rdev) & ~0x1ff))
                return -EINVAL;
 
-       if (unlikely(test_default_acl && test_default_acl(dvp))) {
+       if (test_default_acl && test_default_acl(dvp)) {
                if (!_ACL_ALLOC(default_acl)) {
                        return -ENOMEM;
                }
@@ -307,11 +295,14 @@ xfs_vn_mknod(
                }
        }
 
-       if (IS_POSIXACL(dir) && !default_acl && xfs_has_fs_struct(current))
+       if (IS_POSIXACL(dir) && !default_acl)
                mode &= ~current->fs->umask;
 
        switch (mode & S_IFMT) {
-       case S_IFCHR: case S_IFBLK: case S_IFIFO: case S_IFSOCK:
+       case S_IFCHR:
+       case S_IFBLK:
+       case S_IFIFO:
+       case S_IFSOCK:
                rdev = sysv_encode_dev(rdev);
        case S_IFREG:
                error = xfs_create(XFS_I(dir), dentry, mode, rdev, &vp, NULL);
@@ -324,32 +315,34 @@ xfs_vn_mknod(
                break;
        }
 
-       if (unlikely(!error)) {
-               error = xfs_init_security(vp, dir);
-               if (error)
-                       xfs_cleanup_inode(dir, vp, dentry, mode);
-       }
+       if (unlikely(error))
+               goto out_free_acl;
 
-       if (unlikely(default_acl)) {
-               if (!error) {
-                       error = _ACL_INHERIT(vp, mode, default_acl);
-                       if (!error)
-                               xfs_iflags_set(XFS_I(vp), XFS_IMODIFIED);
-                       else
-                               xfs_cleanup_inode(dir, vp, dentry, mode);
-               }
+       error = xfs_init_security(vp, dir);
+       if (unlikely(error))
+               goto out_cleanup_inode;
+
+       if (default_acl) {
+               error = _ACL_INHERIT(vp, mode, default_acl);
+               if (unlikely(error))
+                       goto out_cleanup_inode;
+               xfs_iflags_set(XFS_I(vp), XFS_IMODIFIED);
                _ACL_FREE(default_acl);
        }
 
-       if (likely(!error)) {
-               ASSERT(vp);
-               ip = vn_to_inode(vp);
+       inode = vn_to_inode(vp);
 
-               if (S_ISDIR(mode))
-                       xfs_validate_fields(ip);
-               d_instantiate(dentry, ip);
-               xfs_validate_fields(dir);
-       }
+       if (S_ISDIR(mode))
+               xfs_validate_fields(inode);
+       d_instantiate(dentry, inode);
+       xfs_validate_fields(dir);
+       return -error;
+
+ out_cleanup_inode:
+       xfs_cleanup_inode(dir, vp, dentry, mode);
+ out_free_acl:
+       if (default_acl)
+               _ACL_FREE(default_acl);
        return -error;
 }