On Wed, Jun 07, 2006 at 05:10:35PM -0700, Dave Hansen wrote:
> 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@xxxxxxxxxx>
> ---
>
> ipc/mqueue.c | 0
> lxc-dave/fs/namei.c | 48 ++++++++++++++++++++++++++++----------------
> lxc-dave/fs/nfsd/vfs.c | 4 +++
> lxc-dave/net/unix/af_unix.c | 4 +++
> 4 files changed, 39 insertions(+), 17 deletions(-)
>
> diff -puN fs/namei.c~elevate-writers-vfs_mknod-try2 fs/namei.c
> --- lxc/fs/namei.c~elevate-writers-vfs_mknod-try2 2006-06-07 16:53:25.000000000 -0700
> +++ lxc-dave/fs/namei.c 2006-06-07 16:53:25.000000000 -0700
> @@ -1852,26 +1852,40 @@ asmlinkage long sys_mknodat(int dfd, con
>
> if (!IS_POSIXACL(nd.dentry->d_inode))
> mode &= ~current->fs->umask;
> - if (!IS_ERR(dentry)) {
> - switch (mode & S_IFMT) {
> - case 0: case S_IFREG:
> - error = vfs_create(nd.dentry->d_inode,dentry,mode,&nd);
> - break;
> - case S_IFCHR: case S_IFBLK:
> - error = vfs_mknod(nd.dentry->d_inode,dentry,mode,
> - new_decode_dev(dev));
> - break;
> - case S_IFIFO: case S_IFSOCK:
> - error = vfs_mknod(nd.dentry->d_inode,dentry,mode,0);
> + if (IS_ERR(dentry))
> + goto out_unlock;
> + error = mnt_want_write(nd.mnt);
> + if (error)
> + goto out_dput;
> + switch (mode & S_IFMT) {
> + case 0: case S_IFREG:
> + error = vfs_create(nd.dentry->d_inode,dentry,mode,&nd);
> + break;
> + case S_IFCHR: case S_IFBLK:
hmm, could you outline some cases where the following
fails, but the previous (above) check succeeded?
(except for dubious locking issues)
> + error = mnt_want_write(nd.mnt);
> + if (error)
> break;
> - case S_IFDIR:
> - error = -EPERM;
> + 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:
same here
> + error = mnt_want_write(nd.mnt);
> + if (error)
> break;
> - default:
> - error = -EINVAL;
> - }
> - dput(dentry);
> + error = vfs_mknod(nd.dentry->d_inode,dentry,mode,0);
> + mnt_drop_write(nd.mnt);
> + break;
> + case S_IFDIR:
> + error = -EPERM;
this will give -EPERM on a r/w filesystem, but
-EROFS on r/o, is that consistant with the current
behaviour?
> + break;
> + default:
> + error = -EINVAL;
same here for -EINVAL and -EROFS, maybe the
mnt_want_write() wants to go into vfs_mknod()?
TIA,
Herbert
> }
> + mnt_drop_write(nd.mnt);
> +out_dput:
> + dput(dentry);
> +out_unlock:
> mutex_unlock(&nd.dentry->d_inode->i_mutex);
> path_release(&nd);
> out:
> diff -puN fs/nfsd/vfs.c~elevate-writers-vfs_mknod-try2 fs/nfsd/vfs.c
> --- lxc/fs/nfsd/vfs.c~elevate-writers-vfs_mknod-try2 2006-06-07 16:53:25.000000000 -0700
> +++ lxc-dave/fs/nfsd/vfs.c 2006-06-07 16:53:25.000000000 -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~elevate-writers-vfs_mknod-try2 net/unix/af_unix.c
> --- lxc/net/unix/af_unix.c~elevate-writers-vfs_mknod-try2 2006-06-07 16:53:25.000000000 -0700
> +++ lxc-dave/net/unix/af_unix.c 2006-06-07 16:53:25.000000000 -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);
> diff -puN ipc/mqueue.c~elevate-writers-vfs_mknod-try2 ipc/mqueue.c
> diff -L xattr.patch -puN /dev/null /dev/null
> _
-
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