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 <haveblue at us.ibm.com> --- 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~18-24-sys-mknodat-elevate-write-count-for-vfs-mknod-create fs/namei.c --- lxc/fs/namei.c~18-24-sys-mknodat-elevate-write-count-for-vfs-mknod-create 2006-12-11 14:22:09.000000000 -0800 +++ lxc-dave/fs/namei.c 2006-12-11 14:22:09.000000000 -0800 @@ -1899,14 +1899,26 @@ 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~18-24-sys-mknodat-elevate-write-count-for-vfs-mknod-create fs/nfsd/vfs.c --- lxc/fs/nfsd/vfs.c~18-24-sys-mknodat-elevate-write-count-for-vfs-mknod-create 2006-12-11 14:22:09.000000000 -0800 +++ lxc-dave/fs/nfsd/vfs.c 2006-12-11 14:22:09.000000000 -0800 @@ -665,6 +665,9 @@ nfsd_open(struct svc_rqst *rqstp, struct /* Disallow write access to files with the append-only bit set * or any access when mandatory locking enabled */ + err = mnt_want_write(fhp->fh_export->ex_mnt); + if (err) + goto out_nfserr; err = nfserr_perm; if (IS_APPEND(inode) && (access & MAY_WRITE)) goto out; @@ -1199,6 +1202,7 @@ nfsd_create(struct svc_rqst *rqstp, stru printk("nfsd: bad file type %o in nfsd_create\n", type); host_err = -EINVAL; } + mnt_drop_write(fhp->fh_export->ex_mnt); if (host_err < 0) goto out_nfserr; diff -puN net/unix/af_unix.c~18-24-sys-mknodat-elevate-write-count-for-vfs-mknod-create net/unix/af_unix.c --- lxc/net/unix/af_unix.c~18-24-sys-mknodat-elevate-write-count-for-vfs-mknod-create 2006-12-11 14:22:09.000000000 -0800 +++ lxc-dave/net/unix/af_unix.c 2006-12-11 14:22:09.000000000 -0800 @@ -816,7 +816,11 @@ 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); _