Re: [RFC PATCH v7 07/24] ceph: add fscrypt_* handling to caps.c

[Xiubo Li <xiubli@xxxxxxxxxx>]

Hi Jeff,

There has some following patches in your "fscrypt" branch, which is not 
posted yet, the commit is:

"3161d2f549db ceph: size handling for encrypted inodes in cap updates"

It seems buggy.

In the encode_cap_msg() you have removed the 'fscrypt_file_len' and and 
added a new 8 bytes' data encoding:

        ceph_encode_32(&p, arg->fscrypt_auth_len);
        ceph_encode_copy(&p, arg->fscrypt_auth, arg->fscrypt_auth_len);
-       ceph_encode_32(&p, arg->fscrypt_file_len);
-       ceph_encode_copy(&p, arg->fscrypt_file, arg->fscrypt_file_len);
+       ceph_encode_32(&p, sizeof(__le64));
+       ceph_encode_64(&p, fc->size);

That means no matter the 'arg->encrypted' is true or not, here it will 
always encode extra 8 bytes' data ?


But in cap_msg_size(), you are making it optional:


 static inline int cap_msg_size(struct cap_msg_args *arg)
 {
        return CAP_MSG_FIXED_FIELDS + arg->fscrypt_auth_len +
-                       arg->fscrypt_file_len;
+                       arg->encrypted ? sizeof(__le64) : 0;
 }


Have I missed something important here ?

Thanks


On 6/25/21 9:58 PM, Jeff Layton wrote:
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
>   fs/ceph/caps.c | 62 +++++++++++++++++++++++++++++++++++++++-----------
>   1 file changed, 49 insertions(+), 13 deletions(-)
>
> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> index 038f59cc4250..1be6c5148700 100644
> --- a/fs/ceph/caps.c
> +++ b/fs/ceph/caps.c
> @@ -13,6 +13,7 @@
>   #include "super.h"
>   #include "mds_client.h"
>   #include "cache.h"
> +#include "crypto.h"
>   #include <linux/ceph/decode.h>
>   #include <linux/ceph/messenger.h>
>   
> @@ -1229,15 +1230,12 @@ struct cap_msg_args {
>   	umode_t			mode;
>   	bool			inline_data;
>   	bool			wake;
> +	u32			fscrypt_auth_len;
> +	u32			fscrypt_file_len;
> +	u8			fscrypt_auth[sizeof(struct ceph_fscrypt_auth)]; // for context
> +	u8			fscrypt_file[sizeof(u64)]; // for size
>   };
>   
> -/*
> - * cap struct size + flock buffer size + inline version + inline data size +
> - * osd_epoch_barrier + oldest_flush_tid
> - */
> -#define CAP_MSG_SIZE (sizeof(struct ceph_mds_caps) + \
> -		      4 + 8 + 4 + 4 + 8 + 4 + 4 + 4 + 8 + 8 + 4)
> -
>   /* Marshal up the cap msg to the MDS */
>   static void encode_cap_msg(struct ceph_msg *msg, struct cap_msg_args *arg)
>   {
> @@ -1253,7 +1251,7 @@ static void encode_cap_msg(struct ceph_msg *msg, struct cap_msg_args *arg)
>   	     arg->size, arg->max_size, arg->xattr_version,
>   	     arg->xattr_buf ? (int)arg->xattr_buf->vec.iov_len : 0);
>   
> -	msg->hdr.version = cpu_to_le16(10);
> +	msg->hdr.version = cpu_to_le16(12);
>   	msg->hdr.tid = cpu_to_le64(arg->flush_tid);
>   
>   	fc = msg->front.iov_base;
> @@ -1324,6 +1322,16 @@ static void encode_cap_msg(struct ceph_msg *msg, struct cap_msg_args *arg)
>   
>   	/* Advisory flags (version 10) */
>   	ceph_encode_32(&p, arg->flags);
> +
> +	/* dirstats (version 11) - these are r/o on the client */
> +	ceph_encode_64(&p, 0);
> +	ceph_encode_64(&p, 0);
> +
> +	/* fscrypt_auth and fscrypt_file (version 12) */
> +	ceph_encode_32(&p, arg->fscrypt_auth_len);
> +	ceph_encode_copy(&p, arg->fscrypt_auth, arg->fscrypt_auth_len);
> +	ceph_encode_32(&p, arg->fscrypt_file_len);
> +	ceph_encode_copy(&p, arg->fscrypt_file, arg->fscrypt_file_len);
>   }
>   
>   /*
> @@ -1445,6 +1453,26 @@ static void __prep_cap(struct cap_msg_args *arg, struct ceph_cap *cap,
>   		}
>   	}
>   	arg->flags = flags;
> +	if (ci->fscrypt_auth_len &&
> +	    WARN_ON_ONCE(ci->fscrypt_auth_len != sizeof(struct ceph_fscrypt_auth))) {
> +		/* Don't set this if it isn't right size */
> +		arg->fscrypt_auth_len = 0;
> +	} else {
> +		arg->fscrypt_auth_len = ci->fscrypt_auth_len;
> +		memcpy(arg->fscrypt_auth, ci->fscrypt_auth,
> +			min_t(size_t, ci->fscrypt_auth_len, sizeof(arg->fscrypt_auth)));
> +	}
> +	/* FIXME: use this to track "real" size */
> +	arg->fscrypt_file_len = 0;
> +}
> +
> +#define CAP_MSG_FIXED_FIELDS (sizeof(struct ceph_mds_caps) + \
> +		      4 + 8 + 4 + 4 + 8 + 4 + 4 + 4 + 8 + 8 + 4 + 8 + 8 + 4 + 4)
> +
> +static inline int cap_msg_size(struct cap_msg_args *arg)
> +{
> +	return CAP_MSG_FIXED_FIELDS + arg->fscrypt_auth_len +
> +			arg->fscrypt_file_len;
>   }
>   
>   /*
> @@ -1457,7 +1485,7 @@ static void __send_cap(struct cap_msg_args *arg, struct ceph_inode_info *ci)
>   	struct ceph_msg *msg;
>   	struct inode *inode = &ci->vfs_inode;
>   
> -	msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, CAP_MSG_SIZE, GFP_NOFS, false);
> +	msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, cap_msg_size(arg), GFP_NOFS, false);
>   	if (!msg) {
>   		pr_err("error allocating cap msg: ino (%llx.%llx) flushing %s tid %llu, requeuing cap.\n",
>   		       ceph_vinop(inode), ceph_cap_string(arg->dirty),
> @@ -1483,10 +1511,6 @@ static inline int __send_flush_snap(struct inode *inode,
>   	struct cap_msg_args	arg;
>   	struct ceph_msg		*msg;
>   
> -	msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, CAP_MSG_SIZE, GFP_NOFS, false);
> -	if (!msg)
> -		return -ENOMEM;
> -
>   	arg.session = session;
>   	arg.ino = ceph_vino(inode).ino;
>   	arg.cid = 0;
> @@ -1524,6 +1548,18 @@ static inline int __send_flush_snap(struct inode *inode,
>   	arg.flags = 0;
>   	arg.wake = false;
>   
> +	/*
> +	 * No fscrypt_auth changes from a capsnap. It will need
> +	 * to update fscrypt_file on size changes (TODO).
> +	 */
> +	arg.fscrypt_auth_len = 0;
> +	arg.fscrypt_file_len = 0;
> +
> +	msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, cap_msg_size(&arg),
> +			   GFP_NOFS, false);
> +	if (!msg)
> +		return -ENOMEM;
> +
>   	encode_cap_msg(msg, &arg);
>   	ceph_con_send(&arg.session->s_con, msg);
>   	return 0;