switch dentry_open() to struct path, make it grab references itself

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 47 insertions, 70 deletions

diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 2dee38d53c73..f8e54f5b9080 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -721,8 +721,8 @@ static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
 /*
  * Invoked when creating a new queue via sys_mq_open
  */
-static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
-                        struct dentry *dentry, int oflag, umode_t mode,
+static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
+                        struct path *path, int oflag, umode_t mode,
                         struct mq_attr *attr)
 {
         const struct cred *cred = current_cred();
@@ -732,9 +732,9 @@ static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
         if (attr) {
                 ret = mq_attr_ok(ipc_ns, attr);
                 if (ret)
-                        goto out;
+                        return ERR_PTR(ret);
                 /* store for use during create */
-                dentry->d_fsdata = attr;
+                path->dentry->d_fsdata = attr;
         } else {
                 struct mq_attr def_attr;
 
@@ -744,71 +744,51 @@ static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
                                           ipc_ns->mq_msgsize_default);
                 ret = mq_attr_ok(ipc_ns, &def_attr);
                 if (ret)
-                        goto out;
+                        return ERR_PTR(ret);
         }
 
         mode &= ~current_umask();
-        ret = mnt_want_write(ipc_ns->mq_mnt);
+        ret = mnt_want_write(path->mnt);
         if (ret)
-                goto out;
-        ret = vfs_create(dir->d_inode, dentry, mode, true);
-        dentry->d_fsdata = NULL;
-        if (ret)
-                goto out_drop_write;
-
-        result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
+                return ERR_PTR(ret);
+        ret = vfs_create(dir, path->dentry, mode, true);
+        path->dentry->d_fsdata = NULL;
+        if (!ret)
+                result = dentry_open(path, oflag, cred);
+        else
+                result = ERR_PTR(ret);
         /*
          * dentry_open() took a persistent mnt_want_write(),
          * so we can now drop this one.
          */
-        mnt_drop_write(ipc_ns->mq_mnt);
+        mnt_drop_write(path->mnt);
         return result;
-
-out_drop_write:
-        mnt_drop_write(ipc_ns->mq_mnt);
-out:
-        dput(dentry);
-        mntput(ipc_ns->mq_mnt);
-        return ERR_PTR(ret);
 }
 
 /* Opens existing queue */
-static struct file *do_open(struct ipc_namespace *ipc_ns,
-                                struct dentry *dentry, int oflag)
+static struct file *do_open(struct path *path, int oflag)
 {
-        int ret;
-        const struct cred *cred = current_cred();
-
         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
                                                   MAY_READ | MAY_WRITE };
-
-        if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
-                ret = -EINVAL;
-                goto err;
-        }
-
-        if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
-                ret = -EACCES;
-                goto err;
-        }
-
-        return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
-
-err:
-        dput(dentry);
-        mntput(ipc_ns->mq_mnt);
-        return ERR_PTR(ret);
+        int acc;
+        if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
+                return ERR_PTR(-EINVAL);
+        acc = oflag2acc[oflag & O_ACCMODE];
+        if (inode_permission(path->dentry->d_inode, acc))
+                return ERR_PTR(-EACCES);
+        return dentry_open(path, oflag, current_cred());
 }
 
 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
                 struct mq_attr __user *, u_attr)
 {
-        struct dentry *dentry;
+        struct path path;
         struct file *filp;
         char *name;
         struct mq_attr attr;
         int fd, error;
         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
+        struct dentry *root = ipc_ns->mq_mnt->mnt_root;
 
         if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
                 return -EFAULT;
@@ -822,52 +802,49 @@ SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
         if (fd < 0)
                 goto out_putname;
 
-        mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
-        dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
-        if (IS_ERR(dentry)) {
-                error = PTR_ERR(dentry);
+        error = 0;
+        mutex_lock(&root->d_inode->i_mutex);
+        path.dentry = lookup_one_len(name, root, strlen(name));
+        if (IS_ERR(path.dentry)) {
+                error = PTR_ERR(path.dentry);
                 goto out_putfd;
         }
-        mntget(ipc_ns->mq_mnt);
+        path.mnt = mntget(ipc_ns->mq_mnt);
 
         if (oflag & O_CREAT) {
-                if (dentry->d_inode) {  /* entry already exists */
-                        audit_inode(name, dentry);
+                if (path.dentry->d_inode) {     /* entry already exists */
+                        audit_inode(name, path.dentry);
                         if (oflag & O_EXCL) {
                                 error = -EEXIST;
                                 goto out;
                         }
-                        filp = do_open(ipc_ns, dentry, oflag);
+                        filp = do_open(&path, oflag);
                 } else {
-                        filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
-                                                dentry, oflag, mode,
+                        filp = do_create(ipc_ns, root->d_inode,
+                                                &path, oflag, mode,
                                                 u_attr ? &attr : NULL);
                 }
         } else {
-                if (!dentry->d_inode) {
+                if (!path.dentry->d_inode) {
                         error = -ENOENT;
                         goto out;
                 }
-                audit_inode(name, dentry);
-                filp = do_open(ipc_ns, dentry, oflag);
+                audit_inode(name, path.dentry);
+                filp = do_open(&path, oflag);
         }
 
-        if (IS_ERR(filp)) {
+        if (!IS_ERR(filp))
+                fd_install(fd, filp);
+        else
                 error = PTR_ERR(filp);
-                goto out_putfd;
-        }
-
-        fd_install(fd, filp);
-        goto out_upsem;
-
 out:
-        dput(dentry);
-        mntput(ipc_ns->mq_mnt);
+        path_put(&path);
 out_putfd:
-        put_unused_fd(fd);
-        fd = error;
-out_upsem:
-        mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
+        if (error) {
+                put_unused_fd(fd);
+                fd = error;
+        }
+        mutex_unlock(&root->d_inode->i_mutex);
 out_putname:
         putname(name);
         return fd;