On Wed, May 16, 2018 at 1:29 PM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote:
> On Tue, May 15, 2018 at 12:26 PM, Amir Goldstein <amir73il@xxxxxxxxx> wrote:
>> Overlayfs should cope with online changes to underlying layer
>> without crashing the kernel, which is what xfstest overlay/019
>> checks.
>>
>> This test may sometimes trigger WARN_ON() in ovl_create_or_link()
>> when linking an overlay inode that has been changed on underlying
>> layer.
>>
>> Replace those WARN_ON() with pr_warn_ratelimited() to prevent
>> test from failing and because this is more appropriate to the
>> use case.
>>
>> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
>> ---
>> fs/overlayfs/dir.c | 14 +++++++++++---
>> 1 file changed, 11 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
>> index 62e6733b755c..25b339278684 100644
>> --- a/fs/overlayfs/dir.c
>> +++ b/fs/overlayfs/dir.c
>> @@ -525,9 +525,17 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
>> if (!err) {
>> struct inode *realinode = d_inode(ovl_dentry_upper(dentry));
>>
>> - WARN_ON(inode->i_mode != realinode->i_mode);
>> - WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid));
>> - WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid));
>> + if (inode->i_mode != realinode->i_mode ||
>> + !uid_eq(inode->i_uid, realinode->i_uid) ||
>> + !gid_eq(inode->i_gid, realinode->i_gid)) {
>> + pr_warn_ratelimited("overlayfs: real inode attributes mismatch (%pd2, %o.%u.%u != %o.%u.%u).\n",
>> + dentry, inode->i_mode,
>> + from_kuid(&init_user_ns, inode->i_uid),
>> + from_kgid(&init_user_ns, inode->i_gid),
>> + realinode->i_mode,
>> + from_kuid(&init_user_ns, realinode->i_uid),
>> + from_kgid(&init_user_ns, realinode->i_gid));
>> + }
>
> How about just dropping the warnings altogether. They didn't discover
> an issue with the code, just something normal, so IMO we should just
> get rid of them.
>
OK. On that subject, do you want to leave the 'debug' argument
to ovl_do_XXX? I started peeling it off slowly from the new helpers,
but maybe we should just yank it completely from the ovl_do_XXX
helpers? pr_debug can be disabled dynamically anyway. right?
Thanks,
Amir.
