[RFD Patch 2/4] Never pass a NULL nameidata to vfs_create()

[jjohansen@suse.de]

Create a nameidata2 struct in nfsd and mqueue so that vfs_create does
need to conditionally pass the vfsmnt.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>

---
 fs/namei.c    |    2 +-
 fs/nfsd/vfs.c |   42 +++++++++++++++++++++++++-----------------
 ipc/mqueue.c  |    7 ++++++-
 3 files changed, 32 insertions(+), 19 deletions(-)

--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1532,7 +1532,7 @@ int vfs_create(struct inode *dir, struct
 		return -EACCES;	/* shouldn't it be ENOSYS? */
 	mode &= S_IALLUGO;
 	mode |= S_IFREG;
-	error = security_inode_create(dir, dentry, nd ? nd->mnt : NULL, mode);
+	error = security_inode_create(dir, dentry, nd->mnt, mode);
 	if (error)
 		return error;
 	DQUOT_INIT(dir);
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1121,7 +1121,8 @@ nfsd_create(struct svc_rqst *rqstp, stru
 		char *fname, int flen, struct iattr *iap,
 		int type, dev_t rdev, struct svc_fh *resfhp)
 {
-	struct dentry	*dentry, *dchild = NULL;
+	struct nameidata2 nd;
+	struct dentry	*dchild = NULL;
 	struct svc_export *exp;
 	struct inode	*dirp;
 	__be32		err;
@@ -1138,9 +1139,11 @@ nfsd_create(struct svc_rqst *rqstp, stru
 	if (err)
 		goto out;
 
-	dentry = fhp->fh_dentry;
+	nd.dentry = fhp->fh_dentry;
 	exp = fhp->fh_export;
-	dirp = dentry->d_inode;
+	nd.mnt = exp->ex_mnt;
+	nd.flags = 0;
+	dirp = nd.dentry->d_inode;
 
 	err = nfserr_notdir;
 	if(!dirp->i_op || !dirp->i_op->lookup)
@@ -1152,7 +1155,7 @@ nfsd_create(struct svc_rqst *rqstp, stru
 	if (!resfhp->fh_dentry) {
 		/* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */
 		fh_lock_nested(fhp, I_MUTEX_PARENT);
-		dchild = lookup_one_len(fname, dentry, flen);
+		dchild = lookup_one_len(fname, nd.dentry, flen);
 		host_err = PTR_ERR(dchild);
 		if (IS_ERR(dchild))
 			goto out_nfserr;
@@ -1166,8 +1169,8 @@ nfsd_create(struct svc_rqst *rqstp, stru
 			/* not actually possible */
 			printk(KERN_ERR
 				"nfsd_create: parent %s/%s not locked!\n",
-				dentry->d_parent->d_name.name,
-				dentry->d_name.name);
+				nd.dentry->d_parent->d_name.name,
+				nd.dentry->d_name.name);
 			err = nfserr_io;
 			goto out;
 		}
@@ -1178,7 +1181,7 @@ nfsd_create(struct svc_rqst *rqstp, stru
 	err = nfserr_exist;
 	if (dchild->d_inode) {
 		dprintk("nfsd_create: dentry %s/%s not negative!\n",
-			dentry->d_name.name, dchild->d_name.name);
+			nd.dentry->d_name.name, dchild->d_name.name);
 		goto out; 
 	}
 
@@ -1192,7 +1195,7 @@ nfsd_create(struct svc_rqst *rqstp, stru
 	err = 0;
 	switch (type) {
 	case S_IFREG:
-		host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
+		host_err = vfs_create(nd.dentry->d_inode, dchild, iap->ia_mode, &nd);
 		break;
 	case S_IFDIR:
 		host_err = vfs_mkdir(dirp, dchild, exp->ex_mnt, iap->ia_mode);
@@ -1212,7 +1215,7 @@ nfsd_create(struct svc_rqst *rqstp, stru
 		goto out_nfserr;
 
 	if (EX_ISSYNC(exp)) {
-		err = nfserrno(nfsd_sync_dir(dentry));
+		err = nfserrno(nfsd_sync_dir(nd.dentry));
 		write_inode_now(dchild->d_inode, 1);
 	}
 
@@ -1252,7 +1255,9 @@ nfsd_create_v3(struct svc_rqst *rqstp, s
 		struct svc_fh *resfhp, int createmode, u32 *verifier,
 	        int *truncp, int *created)
 {
-	struct dentry	*dentry, *dchild = NULL;
+	struct nameidata2 nd;
+	struct dentry	*dchild = NULL;
+	struct svc_export *exp;
 	struct inode	*dirp;
 	__be32		err;
 	int		host_err;
@@ -1270,8 +1275,11 @@ nfsd_create_v3(struct svc_rqst *rqstp, s
 	if (err)
 		goto out;
 
-	dentry = fhp->fh_dentry;
-	dirp = dentry->d_inode;
+	nd.dentry = fhp->fh_dentry;
+	exp = fhp->fh_export;
+	nd.mnt = exp->ex_mnt;
+	nd.flags = 0;
+	dirp = nd.dentry->d_inode;
 
 	/* Get all the sanity checks out of the way before
 	 * we lock the parent. */
@@ -1283,12 +1291,12 @@ nfsd_create_v3(struct svc_rqst *rqstp, s
 	/*
 	 * Compose the response file handle.
 	 */
-	dchild = lookup_one_len(fname, dentry, flen);
+	dchild = lookup_one_len(fname, nd.dentry, flen);
 	host_err = PTR_ERR(dchild);
 	if (IS_ERR(dchild))
 		goto out_nfserr;
 
-	err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
+	err = fh_compose(resfhp, exp, dchild, fhp);
 	if (err)
 		goto out;
 
@@ -1334,14 +1342,14 @@ nfsd_create_v3(struct svc_rqst *rqstp, s
 		goto out;
 	}
 
-	host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
+	host_err = vfs_create(nd.dentry->d_inode, dchild, iap->ia_mode, &nd);
 	if (host_err < 0)
 		goto out_nfserr;
 	if (created)
 		*created = 1;
 
-	if (EX_ISSYNC(fhp->fh_export)) {
-		err = nfserrno(nfsd_sync_dir(dentry));
+	if (EX_ISSYNC(exp)) {
+		err = nfserrno(nfsd_sync_dir(nd.dentry));
 		/* setattr will sync the child (or not) */
 	}
 
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -603,9 +603,14 @@ static int mq_attr_ok(struct mq_attr *at
 static struct file *do_create(struct dentry *dir, struct dentry *dentry,
 			int oflag, mode_t mode, struct mq_attr __user *u_attr)
 {
+	struct nameidata2 nd;
 	struct mq_attr attr;
 	int ret;
 
+	nd.dentry = dir;
+	nd.mnt = NULL;  /* Not a mounted filesystem */
+	nd.flags = 0;
+
 	if (u_attr) {
 		ret = -EFAULT;
 		if (copy_from_user(&attr, u_attr, sizeof(attr)))
@@ -618,7 +623,7 @@ static struct file *do_create(struct den
 	}
 
 	mode &= ~current->fs->umask;
-	ret = vfs_create(dir->d_inode, dentry, mode, NULL);
+	ret = vfs_create(dir->d_inode, dentry, mode, &nd);
 	dentry->d_fsdata = NULL;
 	if (ret)
 		goto out;

-- 
-
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