From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: [RFC][PATCH 16/20] sys_mknodat(): elevate write count for vfs_mknod/create() Date: Fri, 16 Jun 2006 16:12:25 -0700 Message-ID: <20060616231225.68636C81@localhost.localdomain> References: <20060616231213.D4C5D6AF@localhost.localdomain> Cc: linux-fsdevel@vger.kernel.org, herbert@13thfloor.at, viro@ftp.linux.org.uk, Dave Hansen Return-path: Received: from e32.co.us.ibm.com ([32.97.110.150]:48094 "EHLO e32.co.us.ibm.com") by vger.kernel.org with ESMTP id S1751587AbWFPXMa (ORCPT ); Fri, 16 Jun 2006 19:12:30 -0400 To: linux-kernel@vger.kernel.org In-Reply-To: <20060616231213.D4C5D6AF@localhost.localdomain> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org 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(). Signed-off-by: Dave Hansen --- lxc-dave/fs/namei.c | 12 ++++++++++++ lxc-dave/fs/nfsd/vfs.c | 4 ++++ lxc-dave/net/unix/af_unix.c | 4 ++++ 3 files changed, 20 insertions(+) diff -puN fs/namei.c~C-elevate-writers-vfs_mknod-try2 fs/namei.c --- lxc/fs/namei.c~C-elevate-writers-vfs_mknod-try2 2006-06-16 15:58:09.000000000 -0700 +++ lxc-dave/fs/namei.c 2006-06-16 15:58:09.000000000 -0700 @@ -1857,14 +1857,26 @@ asmlinkage long sys_mknodat(int dfd, con if (!IS_ERR(dentry)) { switch (mode & S_IFMT) { case 0: case S_IFREG: + error = mnt_want_write(nd.mnt); + if (error) + break; error = vfs_create(nd.dentry->d_inode,dentry,mode,&nd); + mnt_drop_write(nd.mnt); break; case S_IFCHR: case S_IFBLK: + error = mnt_want_write(nd.mnt); + if (error) + break; error = vfs_mknod(nd.dentry->d_inode,dentry,mode, new_decode_dev(dev)); + mnt_drop_write(nd.mnt); break; case S_IFIFO: case S_IFSOCK: + error = mnt_want_write(nd.mnt); + if (error) + break; error = vfs_mknod(nd.dentry->d_inode,dentry,mode,0); + mnt_drop_write(nd.mnt); break; case S_IFDIR: error = -EPERM; diff -puN fs/nfsd/vfs.c~C-elevate-writers-vfs_mknod-try2 fs/nfsd/vfs.c --- lxc/fs/nfsd/vfs.c~C-elevate-writers-vfs_mknod-try2 2006-06-16 15:58:09.000000000 -0700 +++ lxc-dave/fs/nfsd/vfs.c 2006-06-16 15:58:09.000000000 -0700 @@ -1153,6 +1153,9 @@ nfsd_create(struct svc_rqst *rqstp, stru /* * Get the dir op function pointer. */ + err = mnt_want_write(fhp->fh_export->ex_mnt); + if (err) + goto out_nfserr; err = nfserr_perm; switch (type) { case S_IFREG: @@ -1171,6 +1174,7 @@ nfsd_create(struct svc_rqst *rqstp, stru printk("nfsd: bad file type %o in nfsd_create\n", type); err = -EINVAL; } + mnt_drop_write(fhp->fh_export->ex_mnt); if (err < 0) goto out_nfserr; diff -puN net/unix/af_unix.c~C-elevate-writers-vfs_mknod-try2 net/unix/af_unix.c --- lxc/net/unix/af_unix.c~C-elevate-writers-vfs_mknod-try2 2006-06-16 15:58:09.000000000 -0700 +++ lxc-dave/net/unix/af_unix.c 2006-06-16 15:58:09.000000000 -0700 @@ -789,7 +789,11 @@ static int unix_bind(struct socket *sock */ mode = S_IFSOCK | (SOCK_INODE(sock)->i_mode & ~current->fs->umask); + err = mnt_want_write(nd.mnt); + if (err) + goto out_mknod_dput; err = vfs_mknod(nd.dentry->d_inode, dentry, mode, 0); + mnt_drop_write(nd.mnt); if (err) goto out_mknod_dput; mutex_unlock(&nd.dentry->d_inode->i_mutex); _