From: Dave Hansen This also uses the little helper in the NFS code to make an if() a little bit less ugly. We introduced the helper at the beginning of the series. Acked-by: Al Viro Signed-off-by: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Andrew Morton --- fs/namei.c | 4 ++++ fs/nfsd/vfs.c | 17 +++++++++++++---- 2 files changed, 17 insertions(+), 4 deletions(-) diff -puN fs/namei.c~r-o-bind-mounts-get-write-access-for-vfs_rename-callers fs/namei.c --- a/fs/namei.c~r-o-bind-mounts-get-write-access-for-vfs_rename-callers +++ a/fs/namei.c @@ -2752,8 +2752,12 @@ static int do_rename(int olddfd, const c if (new_dentry == trap) goto exit5; + error = mnt_want_write(oldnd.path.mnt); + if (error) + goto exit5; error = vfs_rename(old_dir->d_inode, old_dentry, new_dir->d_inode, new_dentry); + mnt_drop_write(oldnd.path.mnt); exit5: dput(new_dentry); exit4: diff -puN fs/nfsd/vfs.c~r-o-bind-mounts-get-write-access-for-vfs_rename-callers fs/nfsd/vfs.c --- a/fs/nfsd/vfs.c~r-o-bind-mounts-get-write-access-for-vfs_rename-callers +++ a/fs/nfsd/vfs.c @@ -1678,13 +1678,20 @@ nfsd_rename(struct svc_rqst *rqstp, stru if (ndentry == trap) goto out_dput_new; -#ifdef MSNFS - if ((ffhp->fh_export->ex_flags & NFSEXP_MSNFS) && + if (svc_msnfs(ffhp) && ((atomic_read(&odentry->d_count) > 1) || (atomic_read(&ndentry->d_count) > 1))) { host_err = -EPERM; - } else -#endif + goto out_dput_new; + } + + host_err = -EXDEV; + if (ffhp->fh_export->ex_mnt != tfhp->fh_export->ex_mnt) + goto out_dput_new; + host_err = mnt_want_write(ffhp->fh_export->ex_mnt); + if (host_err) + goto out_dput_new; + host_err = vfs_rename(fdir, odentry, tdir, ndentry); if (!host_err && EX_ISSYNC(tfhp->fh_export)) { host_err = nfsd_sync_dir(tdentry); @@ -1692,6 +1699,8 @@ nfsd_rename(struct svc_rqst *rqstp, stru host_err = nfsd_sync_dir(fdentry); } + mnt_drop_write(ffhp->fh_export->ex_mnt); + out_dput_new: dput(ndentry); out_dput_old: _