[PATCH] switch all filesystems over to d_obtain_alias

Switch all users of d_alloc_anon to d_obtain_alias.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/dcache.c

@@ -1187,17 +1187,17 @@ struct dentry * d_alloc_anon(struct inode *inode)
  * allocating a new one.
  *
  * On successful return, the reference to the inode has been transferred
- * to the dentry.  If %NULL is returned (indicating kmalloc failure),
- * the reference on the inode has been released.  To make it easier
- * to use in export operations a NULL or IS_ERR inode may be passed in
- * and will be casted to the corresponding NULL or IS_ERR dentry.
+ * to the dentry.  In case of an error the reference on the inode is released.
+ * To make it easier to use in export operations a %NULL or IS_ERR inode may
+ * be passed in and will be the error will be propagate to the return value,
+ * with a %NULL @inode replaced by ERR_PTR(-ESTALE).
  */
 struct dentry *d_obtain_alias(struct inode *inode)
 {
 	struct dentry *dentry;
 
 	if (!inode)
-		return NULL;
+		return ERR_PTR(-ESTALE);
 	if (IS_ERR(inode))
 		return ERR_CAST(inode);
 

fs/efs/namei.c

@@ -112,35 +112,14 @@ struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
 
 struct dentry *efs_get_parent(struct dentry *child)
 {
-	struct dentry *parent;
-	struct inode *inode;
+	struct dentry *parent = ERR_PTR(-ENOENT);
 	efs_ino_t ino;
-	long error;
 
 	lock_kernel();
-
-	error = -ENOENT;
 	ino = efs_find_entry(child->d_inode, "..", 2);
-	if (!ino)
-		goto fail;
-
-	inode = efs_iget(child->d_inode->i_sb, ino);
-	if (IS_ERR(inode)) {
-		error = PTR_ERR(inode);
-		goto fail;
-	}
-
-	error = -ENOMEM;
-	parent = d_alloc_anon(inode);
-	if (!parent)
-		goto fail_iput;
-
+	if (ino)
+		parent = d_obtain_alias(efs_iget(child->d_inode->i_sb, ino));
 	unlock_kernel();
-	return parent;
 
- fail_iput:
-	iput(inode);
- fail:
-	unlock_kernel();
-	return ERR_PTR(error);
+	return parent;
 }

fs/exportfs/expfs.c

@@ -366,8 +366,6 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
 	 * Try to get any dentry for the given file handle from the filesystem.
 	 */
 	result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type);
-	if (!result)
-		result = ERR_PTR(-ESTALE);
 	if (IS_ERR(result))
 		return result;
 
@@ -422,8 +420,6 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
 
 		target_dir = nop->fh_to_parent(mnt->mnt_sb, fid,
 				fh_len, fileid_type);
-		if (!target_dir)
-			goto err_result;
 		err = PTR_ERR(target_dir);
 		if (IS_ERR(target_dir))
 			goto err_result;

fs/ext2/namei.c

@@ -73,8 +73,6 @@ static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, str
 struct dentry *ext2_get_parent(struct dentry *child)
 {
 	unsigned long ino;
-	struct dentry *parent;
-	struct inode *inode;
 	struct dentry dotdot;
 
 	dotdot.d_name.name = "..";
@@ -83,16 +81,7 @@ struct dentry *ext2_get_parent(struct dentry *child)
 	ino = ext2_inode_by_name(child->d_inode, &dotdot);
 	if (!ino)
 		return ERR_PTR(-ENOENT);
-	inode = ext2_iget(child->d_inode->i_sb, ino);
-
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
-	parent = d_alloc_anon(inode);
-	if (!parent) {
-		iput(inode);
-		parent = ERR_PTR(-ENOMEM);
-	}
-	return parent;
+	return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino));
 } 
 
 /*

fs/ext3/namei.c

@@ -1057,8 +1057,6 @@ static struct dentry *ext3_lookup(struct inode * dir, struct dentry *dentry, str
 struct dentry *ext3_get_parent(struct dentry *child)
 {
 	unsigned long ino;
-	struct dentry *parent;
-	struct inode *inode;
 	struct dentry dotdot;
 	struct ext3_dir_entry_2 * de;
 	struct buffer_head *bh;
@@ -1068,7 +1066,6 @@ struct dentry *ext3_get_parent(struct dentry *child)
 	dotdot.d_parent = child; /* confusing, isn't it! */
 
 	bh = ext3_find_entry(&dotdot, &de);
-	inode = NULL;
 	if (!bh)
 		return ERR_PTR(-ENOENT);
 	ino = le32_to_cpu(de->inode);
@@ -1080,16 +1077,7 @@ struct dentry *ext3_get_parent(struct dentry *child)
 		return ERR_PTR(-EIO);
 	}
 
-	inode = ext3_iget(child->d_inode->i_sb, ino);
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
-
-	parent = d_alloc_anon(inode);
-	if (!parent) {
-		iput(inode);
-		parent = ERR_PTR(-ENOMEM);
-	}
-	return parent;
+	return d_obtain_alias(ext3_iget(child->d_inode->i_sb, ino));
 }
 
 #define S_SHIFT 12

fs/ext4/namei.c

@@ -1083,16 +1083,7 @@ struct dentry *ext4_get_parent(struct dentry *child)
 		return ERR_PTR(-EIO);
 	}
 
-	inode = ext4_iget(child->d_inode->i_sb, ino);
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
-
-	parent = d_alloc_anon(inode);
-	if (!parent) {
-		iput(inode);
-		parent = ERR_PTR(-ENOMEM);
-	}
-	return parent;
+	return d_obtain_alias(ext4_iget(child->d_inode->i_sb, ino));
 }
 
 #define S_SHIFT 12

fs/fat/inode.c

@@ -681,33 +681,24 @@ static struct dentry *fat_fh_to_dentry(struct super_block *sb,
 			inode = NULL;
 		}
 	}
-	if (!inode) {
-		/* For now, do nothing
-		 * What we could do is:
-		 * follow the file starting at fh[4], and record
-		 * the ".." entry, and the name of the fh[2] entry.
-		 * The follow the ".." file finding the next step up.
-		 * This way we build a path to the root of
-		 * the tree. If this works, we lookup the path and so
-		 * get this inode into the cache.
-		 * Finally try the fat_iget lookup again
-		 * If that fails, then weare totally out of luck
-		 * But all that is for another day
-		 */
-	}
-	if (!inode)
-		return ERR_PTR(-ESTALE);
-
 
-	/* now to find a dentry.
-	 * If possible, get a well-connected one
+	/*
+	 * For now, do nothing if the inode is not found.
+	 *
+	 * What we could do is:
+	 *
+	 *	- follow the file starting at fh[4], and record the ".." entry,
+	 *	  and the name of the fh[2] entry.
+	 *	- then follow the ".." file finding the next step up.
+	 *
+	 * This way we build a path to the root of the tree. If this works, we
+	 * lookup the path and so get this inode into the cache.  Finally try
+	 * the fat_iget lookup again.  If that fails, then we are totally out
+	 * of luck.  But all that is for another day
 	 */
-	result = d_alloc_anon(inode);
-	if (result == NULL) {
-		iput(inode);
-		return ERR_PTR(-ENOMEM);
-	}
-	result->d_op = sb->s_root->d_op;
+	result = d_obtain_alias(inode);
+	if (!IS_ERR(result))
+		result->d_op = sb->s_root->d_op;
 	return result;
 }
 
@@ -754,15 +745,8 @@ static struct dentry *fat_get_parent(struct dentry *child)
 	}
 	inode = fat_build_inode(sb, de, i_pos);
 	brelse(bh);
-	if (IS_ERR(inode)) {
-		parent = ERR_CAST(inode);
-		goto out;
-	}
-	parent = d_alloc_anon(inode);
-	if (!parent) {
-		iput(inode);
-		parent = ERR_PTR(-ENOMEM);
-	}
+
+	parent = d_obtain_alias(inode);
 out:
 	unlock_super(sb);
 

fs/fuse/inode.c

@@ -596,12 +596,8 @@ static struct dentry *fuse_get_dentry(struct super_block *sb,
 	if (inode->i_generation != handle->generation)
 		goto out_iput;
 
-	entry = d_alloc_anon(inode);
-	err = -ENOMEM;
-	if (!entry)
-		goto out_iput;
-
-	if (get_node_id(inode) != FUSE_ROOT_ID) {
+	entry = d_obtain_alias(inode);
+	if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) {
 		entry->d_op = &fuse_dentry_operations;
 		fuse_invalidate_entry_cache(entry);
 	}
@@ -696,17 +692,14 @@ static struct dentry *fuse_get_parent(struct dentry *child)
 	name.name = "..";
 	err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
 			       &name, &outarg, &inode);
-	if (err && err != -ENOENT)
+	if (err) {
+		if (err == -ENOENT)
+			return ERR_PTR(-ESTALE);
 		return ERR_PTR(err);
-	if (err || !inode)
-		return ERR_PTR(-ESTALE);
-
-	parent = d_alloc_anon(inode);
-	if (!parent) {
-		iput(inode);
-		return ERR_PTR(-ENOMEM);
 	}
-	if (get_node_id(inode) != FUSE_ROOT_ID) {
+
+	parent = d_obtain_alias(inode);
+	if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) {
 		parent->d_op = &fuse_dentry_operations;
 		fuse_invalidate_entry_cache(parent);
 	}

fs/gfs2/ops_export.c

@@ -130,28 +130,17 @@ static int gfs2_get_name(struct dentry *parent, char *name,
 static struct dentry *gfs2_get_parent(struct dentry *child)
 {
 	struct qstr dotdot;
-	struct inode *inode;
 	struct dentry *dentry;
 
-	gfs2_str2qstr(&dotdot, "..");
-	inode = gfs2_lookupi(child->d_inode, &dotdot, 1);
-
-	if (!inode)
-		return ERR_PTR(-ENOENT);
 	/*
-	 * In case of an error, @inode carries the error value, and we
-	 * have to return that as a(n invalid) pointer to dentry.
+	 * XXX(hch): it would be a good idea to keep this around as a
+	 *	     static variable.
 	 */
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
-
-	dentry = d_alloc_anon(inode);
-	if (!dentry) {
-		iput(inode);
-		return ERR_PTR(-ENOMEM);
-	}
+	gfs2_str2qstr(&dotdot, "..");
 
-	dentry->d_op = &gfs2_dops;
+	dentry = d_obtain_alias(gfs2_lookupi(child->d_inode, &dotdot, 1));
+	if (!IS_ERR(dentry))
+		dentry->d_op = &gfs2_dops;
 	return dentry;
 }
 
@@ -233,13 +222,9 @@ static struct dentry *gfs2_get_dentry(struct super_block *sb,
 	gfs2_glock_dq_uninit(&i_gh);
 
 out_inode:
-	dentry = d_alloc_anon(inode);
-	if (!dentry) {
-		iput(inode);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	dentry->d_op = &gfs2_dops;
+	dentry = d_obtain_alias(inode);
+	if (!IS_ERR(dentry))
+		dentry->d_op = &gfs2_dops;
 	return dentry;
 
 fail_rgd:

fs/isofs/export.c

@@ -22,7 +22,7 @@ isofs_export_iget(struct super_block *sb,
 		  __u32 generation)
 {
 	struct inode *inode;
-	struct dentry *result;
+
 	if (block == 0)
 		return ERR_PTR(-ESTALE);
 	inode = isofs_iget(sb, block, offset);
@@ -32,12 +32,7 @@ isofs_export_iget(struct super_block *sb,
 		iput(inode);
 		return ERR_PTR(-ESTALE);
 	}
-	result = d_alloc_anon(inode);
-	if (!result) {
-		iput(inode);
-		return ERR_PTR(-ENOMEM);
-	}
-	return result;
+	return d_obtain_alias(inode);
 }
 
 /* This function is surprisingly simple.  The trick is understanding
@@ -51,7 +46,6 @@ static struct dentry *isofs_export_get_parent(struct dentry *child)
 	unsigned long parent_offset = 0;
 	struct inode *child_inode = child->d_inode;
 	struct iso_inode_info *e_child_inode = ISOFS_I(child_inode);
-	struct inode *parent_inode = NULL;
 	struct iso_directory_record *de = NULL;
 	struct buffer_head * bh = NULL;
 	struct dentry *rv = NULL;
@@ -104,28 +98,11 @@ static struct dentry *isofs_export_get_parent(struct dentry *child)
 	/* Normalize */
 	isofs_normalize_block_and_offset(de, &parent_block, &parent_offset);
 
-	/* Get the inode. */
-	parent_inode = isofs_iget(child_inode->i_sb,
-				  parent_block,
-				  parent_offset);
-	if (IS_ERR(parent_inode)) {
-		rv = ERR_CAST(parent_inode);
-		if (rv != ERR_PTR(-ENOMEM))
-			rv = ERR_PTR(-EACCES);
-		goto out;
-	}
-
-	/* Allocate the dentry. */
-	rv = d_alloc_anon(parent_inode);
-	if (rv == NULL) {
-		rv = ERR_PTR(-ENOMEM);
-		goto out;
-	}
-
+	rv = d_obtain_alias(isofs_iget(child_inode->i_sb, parent_block,
+				     parent_offset));
  out:
-	if (bh) {
+	if (bh)
 		brelse(bh);
-	}
 	return rv;
 }
 

fs/jfs/namei.c

@@ -1511,25 +1511,12 @@ struct dentry *jfs_fh_to_parent(struct super_block *sb, struct fid *fid,
 
 struct dentry *jfs_get_parent(struct dentry *dentry)
 {
-	struct super_block *sb = dentry->d_inode->i_sb;
-	struct dentry *parent = ERR_PTR(-ENOENT);
-	struct inode *inode;
 	unsigned long parent_ino;
 
 	parent_ino =
 		le32_to_cpu(JFS_IP(dentry->d_inode)->i_dtroot.header.idotdot);
-	inode = jfs_iget(sb, parent_ino);
-	if (IS_ERR(inode)) {
-		parent = ERR_CAST(inode);
-	} else {
-		parent = d_alloc_anon(inode);
-		if (!parent) {
-			parent = ERR_PTR(-ENOMEM);
-			iput(inode);
-		}
-	}
 
-	return parent;
+	return d_obtain_alias(jfs_iget(dentry->d_inode->i_sb, parent_ino));
 }
 
 const struct inode_operations jfs_dir_inode_operations = {

fs/nfs/getroot.c

@@ -107,11 +107,10 @@ struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
 	 * if the dentry tree reaches them; however if the dentry already
 	 * exists, we'll pick it up at this point and use it as the root
 	 */
-	mntroot = d_alloc_anon(inode);
-	if (!mntroot) {
-		iput(inode);
+	mntroot = d_obtain_alias(inode);
+	if (IS_ERR(mntroot)) {
 		dprintk("nfs_get_root: get root dentry failed\n");
-		return ERR_PTR(-ENOMEM);
+		return mntroot;
 	}
 
 	security_d_instantiate(mntroot, inode);
@@ -277,11 +276,10 @@ struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
 	 * if the dentry tree reaches them; however if the dentry already
 	 * exists, we'll pick it up at this point and use it as the root
 	 */
-	mntroot = d_alloc_anon(inode);
-	if (!mntroot) {
-		iput(inode);
+	mntroot = d_obtain_alias(inode);
+	if (IS_ERR(mntroot)) {
 		dprintk("nfs_get_root: get root dentry failed\n");
-		return ERR_PTR(-ENOMEM);
+		return mntroot;
 	}
 
 	security_d_instantiate(mntroot, inode);

fs/ntfs/namei.c

@@ -304,8 +304,6 @@ static struct dentry *ntfs_get_parent(struct dentry *child_dent)
 	ntfs_attr_search_ctx *ctx;
 	ATTR_RECORD *attr;
 	FILE_NAME_ATTR *fn;
-	struct inode *parent_vi;
-	struct dentry *parent_dent;
 	unsigned long parent_ino;
 	int err;
 
@@ -345,24 +343,8 @@ try_next:
 	/* Release the search context and the mft record of the child. */
 	ntfs_attr_put_search_ctx(ctx);
 	unmap_mft_record(ni);
-	/* Get the inode of the parent directory. */
-	parent_vi = ntfs_iget(vi->i_sb, parent_ino);
-	if (IS_ERR(parent_vi) || unlikely(is_bad_inode(parent_vi))) {
-		if (!IS_ERR(parent_vi))
-			iput(parent_vi);
-		ntfs_error(vi->i_sb, "Failed to get parent directory inode "
-				"0x%lx of child inode 0x%lx.", parent_ino,
-				vi->i_ino);
-		return ERR_PTR(-EACCES);
-	}
-	/* Finally get a dentry for the parent directory and return it. */
-	parent_dent = d_alloc_anon(parent_vi);
-	if (unlikely(!parent_dent)) {
-		iput(parent_vi);
-		return ERR_PTR(-ENOMEM);
-	}
-	ntfs_debug("Done for inode 0x%lx.", vi->i_ino);
-	return parent_dent;
+
+	return d_obtain_alias(ntfs_iget(vi->i_sb, parent_ino));
 }
 
 static struct inode *ntfs_nfs_get_inode(struct super_block *sb,

fs/ocfs2/export.c

@@ -68,14 +68,9 @@ static struct dentry *ocfs2_get_dentry(struct super_block *sb,
 		return ERR_PTR(-ESTALE);
 	}
 
-	result = d_alloc_anon(inode);
-
-	if (!result) {
-		iput(inode);
-		mlog_errno(-ENOMEM);
-		return ERR_PTR(-ENOMEM);
-	}
-	result->d_op = &ocfs2_dentry_ops;
+	result = d_obtain_alias(inode);
+	if (!IS_ERR(result))
+		result->d_op = &ocfs2_dentry_ops;
 
 	mlog_exit_ptr(result);
 	return result;
@@ -86,7 +81,6 @@ static struct dentry *ocfs2_get_parent(struct dentry *child)
 	int status;
 	u64 blkno;
 	struct dentry *parent;
-	struct inode *inode;
 	struct inode *dir = child->d_inode;
 
 	mlog_entry("(0x%p, '%.*s')\n", child,
@@ -109,21 +103,9 @@ static struct dentry *ocfs2_get_parent(struct dentry *child)
 		goto bail_unlock;
 	}
 
-	inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0);
-	if (IS_ERR(inode)) {
-		mlog(ML_ERROR, "Unable to create inode %llu\n",
-		     (unsigned long long)blkno);
-		parent = ERR_PTR(-EACCES);
-		goto bail_unlock;
-	}
-
-	parent = d_alloc_anon(inode);
-	if (!parent) {
-		iput(inode);
-		parent = ERR_PTR(-ENOMEM);
-	}
-
-	parent->d_op = &ocfs2_dentry_ops;
+	parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
+	if (!IS_ERR(parent))
+		parent->d_op = &ocfs2_dentry_ops;
 
 bail_unlock:
 	ocfs2_inode_unlock(dir, 0);

fs/reiserfs/inode.c

@@ -1522,7 +1522,6 @@ static struct dentry *reiserfs_get_dentry(struct super_block *sb,
 
 {
 	struct cpu_key key;
-	struct dentry *result;
 	struct inode *inode;
 
 	key.on_disk_key.k_objectid = objectid;
@@ -1535,16 +1534,8 @@ static struct dentry *reiserfs_get_dentry(struct super_block *sb,
 		inode = NULL;
 	}
 	reiserfs_write_unlock(sb);
-	if (!inode)
-		inode = ERR_PTR(-ESTALE);
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
-	result = d_alloc_anon(inode);
-	if (!result) {
-		iput(inode);
-		return ERR_PTR(-ENOMEM);
-	}
-	return result;
+
+	return d_obtain_alias(inode);
 }
 
 struct dentry *reiserfs_fh_to_dentry(struct super_block *sb, struct fid *fid,

fs/reiserfs/namei.c

@@ -383,7 +383,6 @@ struct dentry *reiserfs_get_parent(struct dentry *child)
 	struct inode *inode = NULL;
 	struct reiserfs_dir_entry de;
 	INITIALIZE_PATH(path_to_entry);
-	struct dentry *parent;
 	struct inode *dir = child->d_inode;
 
 	if (dir->i_nlink == 0) {
@@ -401,15 +400,7 @@ struct dentry *reiserfs_get_parent(struct dentry *child)
 	inode = reiserfs_iget(dir->i_sb, (struct cpu_key *)&(de.de_dir_id));
 	reiserfs_write_unlock(dir->i_sb);
 
-	if (!inode || IS_ERR(inode)) {
-		return ERR_PTR(-EACCES);
-	}
-	parent = d_alloc_anon(inode);
-	if (!parent) {
-		iput(inode);
-		parent = ERR_PTR(-ENOMEM);
-	}
-	return parent;
+	return d_obtain_alias(inode);
 }
 
 /* add entry to the directory (entry can be hidden). 

fs/udf/namei.c

@@ -1243,7 +1243,6 @@ end_rename:
 
 static struct dentry *udf_get_parent(struct dentry *child)
 {
-	struct dentry *parent;
 	struct inode *inode = NULL;
 	struct dentry dotdot;
 	struct fileIdentDesc cfi;
@@ -1266,13 +1265,7 @@ static struct dentry *udf_get_parent(struct dentry *child)
 		goto out_unlock;
 	unlock_kernel();
 
-	parent = d_alloc_anon(inode);
-	if (!parent) {
-		iput(inode);
-		parent = ERR_PTR(-ENOMEM);
-	}
-
-	return parent;
+	return d_obtain_alias(inode);
 out_unlock:
 	unlock_kernel();
 	return ERR_PTR(-EACCES);
@@ -1283,7 +1276,6 @@ static struct dentry *udf_nfs_get_inode(struct super_block *sb, u32 block,
 					u16 partref, __u32 generation)
 {
 	struct inode *inode;
-	struct dentry *result;
 	kernel_lb_addr loc;
 
 	if (block == 0)
@@ -1300,12 +1292,7 @@ static struct dentry *udf_nfs_get_inode(struct super_block *sb, u32 block,
 		iput(inode);
 		return ERR_PTR(-ESTALE);
 	}
-	result = d_alloc_anon(inode);
-	if (!result) {
-		iput(inode);
-		return ERR_PTR(-ENOMEM);
-	}
-	return result;
+	return d_obtain_alias(inode);
 }
 
 static struct dentry *udf_fh_to_dentry(struct super_block *sb,

fs/xfs/linux-2.6/xfs_export.c

@@ -148,7 +148,6 @@ xfs_fs_fh_to_dentry(struct super_block *sb, struct fid *fid,
 {
 	struct xfs_fid64	*fid64 = (struct xfs_fid64 *)fid;
 	struct inode		*inode = NULL;
-	struct dentry		*result;
 
 	if (fh_len < xfs_fileid_length(fileid_type))
 		return NULL;
@@ -164,16 +163,7 @@ xfs_fs_fh_to_dentry(struct super_block *sb, struct fid *fid,
 		break;
 	}
 
-	if (!inode)
-		return NULL;
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
-	result = d_alloc_anon(inode);
-	if (!result) {
-		iput(inode);
-		return ERR_PTR(-ENOMEM);
-	}
-	return result;
+	return d_obtain_alias(inode);
 }
 
 STATIC struct dentry *
@@ -182,7 +172,6 @@ xfs_fs_fh_to_parent(struct super_block *sb, struct fid *fid,
 {
 	struct xfs_fid64	*fid64 = (struct xfs_fid64 *)fid;
 	struct inode		*inode = NULL;
-	struct dentry		*result;
 
 	switch (fileid_type) {
 	case FILEID_INO32_GEN_PARENT:
@@ -195,16 +184,7 @@ xfs_fs_fh_to_parent(struct super_block *sb, struct fid *fid,
 		break;
 	}
 
-	if (!inode)
-		return NULL;
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
-	result = d_alloc_anon(inode);
-	if (!result) {
-		iput(inode);
-		return ERR_PTR(-ENOMEM);
-	}
-	return result;
+	return d_obtain_alias(inode);
 }
 
 STATIC struct dentry *
@@ -213,18 +193,12 @@ xfs_fs_get_parent(
 {
 	int			error;
 	struct xfs_inode	*cip;
-	struct dentry		*parent;
 
 	error = xfs_lookup(XFS_I(child->d_inode), &xfs_name_dotdot, &cip, NULL);
 	if (unlikely(error))
 		return ERR_PTR(-error);
 
-	parent = d_alloc_anon(VFS_I(cip));
-	if (unlikely(!parent)) {
-		iput(VFS_I(cip));
-		return ERR_PTR(-ENOMEM);
-	}
-	return parent;
+	return d_obtain_alias(VFS_I(cip));
 }
 
 const struct export_operations xfs_export_operations = {

fs/xfs/linux-2.6/xfs_ioctl.c

@@ -311,11 +311,10 @@ xfs_open_by_handle(
 		return new_fd;
 	}
 
-	dentry = d_alloc_anon(inode);
-	if (dentry == NULL) {
-		iput(inode);
+	dentry = d_obtain_alias(inode);
+	if (IS_ERR(dentry)) {
 		put_unused_fd(new_fd);
-		return -XFS_ERROR(ENOMEM);
+		return PTR_ERR(dentry);
 	}
 
 	/* Ensure umount returns EBUSY on umounts while this file is open. */