Hi Miklos
Any suggestion for the patch?
Best Regards,
Chengguang
> 在 2017年11月13日，下午11:59，Chengguang Xu <cgxu@xxxxxxxxxxxx> 写道：
>
> When upperdir has project quota and has different project id with workdir,
> write may fail with error message "Invalid cross-device link" although mounted on r/w mode.
> This patch checks project quota information of upperdir/workdir during ovl_fill_super(),
> and if different mount on r/o mode. It doesn’t check detail inherit flag because
> the implementations are different in specific filesystems.
>
> Signed-off-by: Chengguang Xu <cgxu@xxxxxxxxxxxx>
> Signed-off-by: Suyue <suyue@xxxxxxxxxxxxx>
> ---
> fs/overlayfs/super.c | 32 +++++++++++++++++++++++++++++++-
> 1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index f5738e9..7b64d5c 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -276,10 +276,34 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
> return err;
> }
>
> +static bool ovl_check_project_quota_ok(struct ovl_fs *ufs)
> +{
> + struct super_block *sb;
> + kprojid_t upperdir_projid = KPROJIDT_INIT(-1);
> + kprojid_t workdir_projid = KPROJIDT_INIT(-1);
> +
> + if (!ufs->upper_mnt || !ufs->workdir)
> + return true;
> +
> + sb = ufs->upper_mnt->mnt_sb;
> + if (!(sb->s_quota_types & QTYPE_MASK_PRJ))
> + return true;
> +
> + if (sb->dq_op && sb->dq_op->get_projid) {
> + sb->dq_op->get_projid(ufs->upper_mnt->mnt_root->d_inode, &upperdir_projid);
> + sb->dq_op->get_projid(ufs->workdir->d_inode, &workdir_projid);
> + if (projid_valid(upperdir_projid) && projid_valid(workdir_projid))
> + if (!projid_eq(upperdir_projid, workdir_projid))
> + return false;
> + }
> +
> + return true;
> +}
> +
> /* Will this overlay be forced to mount/remount ro? */
> static bool ovl_force_readonly(struct ovl_fs *ufs)
> {
> - return (!ufs->upper_mnt || !ufs->workdir);
> + return (!ufs->upper_mnt || !ufs->workdir || !ovl_check_project_quota_ok(ufs));
> }
>
> /**
> @@ -1060,6 +1084,12 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
> else if (ufs->upper_mnt->mnt_sb != ufs->same_sb)
> ufs->same_sb = NULL;
>
> + /* if upperdir and workdir have different project quota ids, we mark overlayfs r/o too */
> + if (!ovl_check_project_quota_ok(ufs)) {
> + pr_warn("overlayfs: mounting read-only because upperdir and workdir have different project quota ids.\n");
> + sb->s_flags |= MS_RDONLY;
> + }
> +
> if (!(ovl_force_readonly(ufs)) && ufs->config.index) {
> /* Verify lower root is upper root origin */
> err = ovl_verify_origin(upperpath.dentry, ufs->lower_mnt[0],
> --
> 1.8.3.1
>
>
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