[PATCH v2] ceph: do not print the whole xattr value if it's too long

[PATCH v2] ceph: do not print the whole xattr value if it's too long

[xiubli]

From: Xiubo Li <xiubli@redhat.com>

If the xattr's value size is long enough the kernel will warn and
then will fail the xfstests test case.

Just print part of the value string if it's too long.

Cc: stable@vger.kernel.org
URL: https://tracker.ceph.com/issues/58404
Signed-off-by: Xiubo Li <xiubli@redhat.com>
---

V2:
- switch to use min() from Jeff's comment
- s/XATTR_MAX_VAL/MAX_XATTR_VAL/g


 fs/ceph/xattr.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index b10d459c2326..887a65279fcf 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -561,6 +561,7 @@ static struct ceph_vxattr *ceph_match_vxattr(struct inode *inode,
 	return NULL;
 }
 
+#define MAX_XATTR_VAL 256
 static int __set_xattr(struct ceph_inode_info *ci,
 			   const char *name, int name_len,
 			   const char *val, int val_len,
@@ -654,8 +655,10 @@ static int __set_xattr(struct ceph_inode_info *ci,
 		dout("__set_xattr_val p=%p\n", p);
 	}
 
-	dout("__set_xattr_val added %llx.%llx xattr %p %.*s=%.*s\n",
-	     ceph_vinop(&ci->netfs.inode), xattr, name_len, name, val_len, val);
+	dout("__set_xattr_val added %llx.%llx xattr %p %.*s=%.*s%s\n",
+	     ceph_vinop(&ci->netfs.inode), xattr, name_len, name,
+	     min(val_len, MAX_XATTR_VAL), val,
+	     val_len > MAX_XATTR_VAL ? "..." : "");
 
 	return 0;
 }
@@ -681,8 +684,9 @@ static struct ceph_inode_xattr *__get_xattr(struct ceph_inode_info *ci,
 		else if (c > 0)
 			p = &(*p)->rb_right;
 		else {
-			dout("__get_xattr %s: found %.*s\n", name,
-			     xattr->val_len, xattr->val);
+			dout("__get_xattr %s: found %.*s%s\n", name,
+			     min(xattr->val_len, MAX_XATTR_VAL), xattr->val,
+			     xattr->val_len > MAX_XATTR_VAL ? "..." : "");
 			return xattr;
 		}
 	}
-- 
2.31.1

Re: [PATCH v2] ceph: do not print the whole xattr value if it's too long

[Ilya Dryomov]

On Wed, Mar 1, 2023 at 2:19 AM <xiubli@redhat.com> wrote:
>
> From: Xiubo Li <xiubli@redhat.com>
>
> If the xattr's value size is long enough the kernel will warn and
> then will fail the xfstests test case.
>
> Just print part of the value string if it's too long.
>
> Cc: stable@vger.kernel.org
> URL: https://tracker.ceph.com/issues/58404

Hi Xiubo,

Does this really need to go to stable kernels?  None of the douts are
printed by default.

> Signed-off-by: Xiubo Li <xiubli@redhat.com>
> ---
>
> V2:
> - switch to use min() from Jeff's comment
> - s/XATTR_MAX_VAL/MAX_XATTR_VAL/g
>
>
>  fs/ceph/xattr.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
> index b10d459c2326..887a65279fcf 100644
> --- a/fs/ceph/xattr.c
> +++ b/fs/ceph/xattr.c
> @@ -561,6 +561,7 @@ static struct ceph_vxattr *ceph_match_vxattr(struct inode *inode,
>         return NULL;
>  }
>
> +#define MAX_XATTR_VAL 256

Perhaps MAX_XATTR_VAL_PRINT_LEN?  Also, I'd add a blank like after the
define -- it's used by more than one function.

Thanks,

                Ilya

Re: [PATCH v2] ceph: do not print the whole xattr value if it's too long

[Xiubo Li]

On 01/03/2023 19:54, Ilya Dryomov wrote:
> On Wed, Mar 1, 2023 at 2:19 AM <xiubli@redhat.com> wrote:
>> From: Xiubo Li <xiubli@redhat.com>
>>
>> If the xattr's value size is long enough the kernel will warn and
>> then will fail the xfstests test case.
>>
>> Just print part of the value string if it's too long.
>>
>> Cc: stable@vger.kernel.org
>> URL: https://tracker.ceph.com/issues/58404
> Hi Xiubo,
>
> Does this really need to go to stable kernels?  None of the douts are
> printed by default.

Ilya,

That's okay, not a must.

>
>> Signed-off-by: Xiubo Li <xiubli@redhat.com>
>> ---
>>
>> V2:
>> - switch to use min() from Jeff's comment
>> - s/XATTR_MAX_VAL/MAX_XATTR_VAL/g
>>
>>
>>   fs/ceph/xattr.c | 12 ++++++++----
>>   1 file changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
>> index b10d459c2326..887a65279fcf 100644
>> --- a/fs/ceph/xattr.c
>> +++ b/fs/ceph/xattr.c
>> @@ -561,6 +561,7 @@ static struct ceph_vxattr *ceph_match_vxattr(struct inode *inode,
>>          return NULL;
>>   }
>>
>> +#define MAX_XATTR_VAL 256
> Perhaps MAX_XATTR_VAL_PRINT_LEN?  Also, I'd add a blank like after the
> define -- it's used by more than one function.

Looks better.

I will revise this.

Thanks

- Xiubo


> Thanks,
>
>                  Ilya
>
-- 
Best Regards,

Xiubo Li (李秀波)

Email: xiubli@redhat.com/xiubli@ibm.com
Slack: @Xiubo Li