Commit 463c3197 authored by Dave Hansen's avatar Dave Hansen Committed by Al Viro
Browse files

[PATCH] r/o bind mounts: get callers of vfs_mknod/create/mkdir() 



This takes care of all of the direct callers of vfs_mknod().
Since a few of these cases also handle normal file creation
as well, this also covers some calls to vfs_create().

So that we don't have to make three mnt_want/drop_write()
calls inside of the switch statement, we move some of its
logic outside of the switch and into a helper function
suggested by Christoph.

This also encapsulates a fix for mknod(S_IFREG) that Miklos
found.

[AV: merged mkdir handling, added missing nfsd pieces]

Acked-by: default avatarAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarDave Hansen <haveblue@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 0622753b

fs/namei.c

+37 −11
Original line number Diff line number Diff line
@@ -1984,6 +1984,23 @@ int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 
	return error;

}



static int may_mknod(mode_t mode)

{

	switch (mode & S_IFMT) {

	case S_IFREG:

	case S_IFCHR:

	case S_IFBLK:

	case S_IFIFO:

	case S_IFSOCK:

	case 0: /* zero mode translates to S_IFREG */

		return 0;

	case S_IFDIR:

		return -EPERM;

	default:

		return -EINVAL;

	}

}



asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,

				unsigned dev)

{
@@ -2002,11 +2019,18 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, 
	if (error)

		goto out;

	dentry = lookup_create(&nd, 0);

	if (IS_ERR(dentry)) {

		error = PTR_ERR(dentry);



		goto out_unlock;

	}

	if (!IS_POSIXACL(nd.path.dentry->d_inode))

		mode &= ~current->fs->umask;

	if (!IS_ERR(dentry)) {

	error = may_mknod(mode);

	if (error)

		goto out_dput;

	error = mnt_want_write(nd.path.mnt);

	if (error)

		goto out_dput;

	switch (mode & S_IFMT) {

		case 0: case S_IFREG:

			error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd);
@@ -2018,14 +2042,11 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, 
		case S_IFIFO: case S_IFSOCK:

			error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0);

			break;

		case S_IFDIR:

			error = -EPERM;

			break;

		default:

			error = -EINVAL;

	}

	mnt_drop_write(nd.path.mnt);

out_dput:

	dput(dentry);

	}

out_unlock:

	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

	path_put(&nd.path);

out:
@@ -2083,7 +2104,12 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode) 


	if (!IS_POSIXACL(nd.path.dentry->d_inode))

		mode &= ~current->fs->umask;

	error = mnt_want_write(nd.path.mnt);

	if (error)

		goto out_dput;

	error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);

	mnt_drop_write(nd.path.mnt);

out_dput:

	dput(dentry);

out_unlock:

	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

fs/nfsd/nfs4recover.c

+4 −0
Original line number Diff line number Diff line
@@ -155,7 +155,11 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) 
		dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");

		goto out_put;

	}

	status = mnt_want_write(rec_dir.path.mnt);

	if (status)

		goto out_put;

	status = vfs_mkdir(rec_dir.path.dentry->d_inode, dentry, S_IRWXU);

	mnt_drop_write(rec_dir.path.mnt);

out_put:

	dput(dentry);

out_unlock:

fs/nfsd/vfs.c

+22 −2
Original line number Diff line number Diff line
@@ -1255,23 +1255,35 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	err = 0;

	switch (type) {

	case S_IFREG:

		host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);

		if (host_err)

			goto out_nfserr;

		host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);

		break;

	case S_IFDIR:

		host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);

		if (host_err)

			goto out_nfserr;

		host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);

		break;

	case S_IFCHR:

	case S_IFBLK:

	case S_IFIFO:

	case S_IFSOCK:

		host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);

		if (host_err)

			goto out_nfserr;

		host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);

		break;

	default:

	        printk("nfsd: bad file type %o in nfsd_create\n", type);

		host_err = -EINVAL;

		goto out_nfserr;

	}

	if (host_err < 0)

	if (host_err < 0) {

		mnt_drop_write(fhp->fh_export->ex_path.mnt);

		goto out_nfserr;

	}



	if (EX_ISSYNC(fhp->fh_export)) {

		err = nfserrno(nfsd_sync_dir(dentry));
@@ -1282,6 +1294,7 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	err2 = nfsd_create_setattr(rqstp, resfhp, iap);

	if (err2)

		err = err2;

	mnt_drop_write(fhp->fh_export->ex_path.mnt);

	/*

	 * Update the file handle to get the new inode info.

	 */
@@ -1359,6 +1372,9 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp, 
		v_atime = verifier[1]&0x7fffffff;

	}

	

	host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);

	if (host_err)

		goto out_nfserr;

	if (dchild->d_inode) {

		err = 0;
@@ -1390,12 +1406,15 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp, 
		case NFS3_CREATE_GUARDED:

			err = nfserr_exist;

		}

		mnt_drop_write(fhp->fh_export->ex_path.mnt);

		goto out;

	}



	host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);

	if (host_err < 0)

	if (host_err < 0) {

		mnt_drop_write(fhp->fh_export->ex_path.mnt);

		goto out_nfserr;

	}

	if (created)

		*created = 1;
@@ -1420,6 +1439,7 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	if (err2)

		err = err2;



	mnt_drop_write(fhp->fh_export->ex_path.mnt);

	/*

	 * Update the filehandle to get the new inode info.

	 */

net/unix/af_unix.c

+4 −0
Original line number Diff line number Diff line
@@ -819,7 +819,11 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 
		 */

		mode = S_IFSOCK |

		       (SOCK_INODE(sock)->i_mode & ~current->fs->umask);

		err = mnt_want_write(nd.path.mnt);

		if (err)

			goto out_mknod_dput;

		err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);

		mnt_drop_write(nd.path.mnt);

		if (err)

			goto out_mknod_dput;

		mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

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