Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Al Viro <viro@ZenIV.linux.org.uk>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Miklos Szeredi <mszeredi@redhat.com>
Subject: [RFC][PATCH 29/42] __shmem_file_setup(): reorder allocations
Date:   Wed, 11 Jul 2018 03:21:53 +0100
Message-Id: <20180711022206.12571-29-viro@ZenIV.linux.org.uk>
In-Reply-To: <20180711022206.12571-1-viro@ZenIV.linux.org.uk>
References: <20180711021136.GN30522@ZenIV.linux.org.uk>
 <20180711022206.12571-1-viro@ZenIV.linux.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Al Viro <viro@zeniv.linux.org.uk>

grab inode and reserve memory first.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 mm/shmem.c | 43 ++++++++++++++++++++-----------------------
 1 file changed, 20 insertions(+), 23 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 2cab84403055..1146a48926bc 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3918,41 +3918,38 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l
 	if (shmem_acct_size(flags, size))
 		return ERR_PTR(-ENOMEM);
 
-	res = ERR_PTR(-ENOMEM);
+	sb = mnt->mnt_sb;
+	inode = shmem_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0, flags);
+	if (unlikely(!inode)) {
+		shmem_unacct_size(flags, size);
+		return ERR_PTR(-ENOSPC);
+	}
+	inode->i_flags |= i_flags;
+	inode->i_size = size;
+	clear_nlink(inode);	/* It is unlinked */
+	res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size));
+	if (IS_ERR(res)) {
+		iput(inode);
+		return res;
+	}
+
 	this.name = name;
 	this.len = strlen(name);
 	this.hash = 0; /* will go */
-	sb = mnt->mnt_sb;
 	path.mnt = mntget(mnt);
 	path.dentry = d_alloc_pseudo(sb, &this);
-	if (!path.dentry)
-		goto put_memory;
+	if (!path.dentry) {
+		iput(inode);
+		return ERR_PTR(-ENOMEM);
+	}
 	d_set_d_op(path.dentry, &anon_ops);
 
-	res = ERR_PTR(-ENOSPC);
-	inode = shmem_get_inode(sb, NULL, S_IFREG | 0777, 0, flags);
-	if (!inode)
-		goto put_memory;
-
-	inode->i_flags |= i_flags;
 	d_instantiate(path.dentry, inode);
-	inode->i_size = size;
-	clear_nlink(inode);	/* It is unlinked */
-	res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size));
-	if (IS_ERR(res))
-		goto put_path;
 
 	res = alloc_file(&path, FMODE_WRITE | FMODE_READ,
 		  &shmem_file_operations);
 	if (IS_ERR(res))
-		goto put_path;
-
-	return res;
-
-put_memory:
-	shmem_unacct_size(flags, size);
-put_path:
-	path_put(&path);
+		path_put(&path);
 	return res;
 }
 
-- 
2.11.0