[PATCH] [SMB3] Send durable handle v2 contexts when use of persistent handles required
Steve French
smfrench at gmail.com
Sun Oct 4 05:03:23 UTC 2015
Updated and resent the 4 patch series onto linux-cifs and also pushed
to cifs-2.6.git experimental branch.
I don't know if channel sequence number in the SMB3 request would also
need to be incremented on disconnect though (the documentation is
confusing on that in MS-SMB2) in the case where we only have one
channel.
Also wondering if I should add a mount option for resilient handles to
allow us to force better reliability of connections to non-clustered
servers (and presumably could work even to Windows 8 and 8.1 and
Windows 10 servers) when the application would prefer that (to the
less strict guarantees of durable handles)
On Sat, Oct 3, 2015 at 2:41 AM, Pavel Shilovsky <piastryyy at gmail.com> wrote:
> 2015-10-01 21:17 GMT+03:00 Steve French <smfrench at gmail.com>:
>> Signed-off-by: Steve French <steve.french at primarydata.com>
>> ---
>> fs/cifs/cifsglob.h | 1 +
>> fs/cifs/smb2pdu.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
>> fs/cifs/smb2pdu.h | 30 ++++++++++++++
>> 3 files changed, 144 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
>> index 51353bb..ec31a03 100644
>> --- a/fs/cifs/cifsglob.h
>> +++ b/fs/cifs/cifsglob.h
>> @@ -1022,6 +1022,7 @@ struct cifs_fid {
>> __u64 persistent_fid; /* persist file id for smb2 */
>> __u64 volatile_fid; /* volatile file id for smb2 */
>> __u8 lease_key[SMB2_LEASE_KEY_SIZE]; /* lease key for smb2 */
>> + __u8 create_guid[16];
>> #endif
>> struct cifs_pending_open *pending_open;
>> unsigned int epoch;
>> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
>> index c744b57..6b899bf 100644
>> --- a/fs/cifs/smb2pdu.c
>> +++ b/fs/cifs/smb2pdu.c
>> @@ -1100,6 +1100,68 @@ create_reconnect_durable_buf(struct cifs_fid *fid)
>> return buf;
>> }
>>
>> +static struct create_durable_v2 *
>> +create_durable_v2_buf(struct cifs_fid *pfid)
>> +{
>> + struct create_durable_v2 *buf;
>> +
>> + buf = kzalloc(sizeof(struct create_durable), GFP_KERNEL);
>> + if (!buf)
>> + return NULL;
>> +
>> + buf->ccontext.DataOffset = cpu_to_le16(offsetof
>> + (struct create_durable_v2, dcontext));
>> + buf->ccontext.DataLength = cpu_to_le32(sizeof(struct durable_context_v2));
>> + buf->ccontext.NameOffset = cpu_to_le16(offsetof
>> + (struct create_durable_v2, Name));
>> + buf->ccontext.NameLength = cpu_to_le16(4);
>> +
>> + buf->dcontext.Timeout = 0; /* Should this be configurable by workload */
>> + buf->dcontext.Flags = cpu_to_le32(SMB2_DHANDLE_FLAG_PERSISTENT);
>> + get_random_bytes(buf->dcontext.CreateGuid, 16);
>> + memcpy(pfid->create_guid, buf->dcontext.CreateGuid, 16);
>> +
>> + /* SMB2_CREATE_DURABLE_HANDLE_REQUEST is "DH2Q" */
>> + buf->Name[0] = 'D';
>> + buf->Name[1] = 'H';
>> + buf->Name[2] = '2';
>> + buf->Name[3] = 'Q';
>> + return buf;
>> +}
>> +
>> +static struct create_durable_handle_reconnect_v2 *
>> +create_reconnect_durable_v2_buf(struct cifs_fid *fid)
>> +{
>> + struct create_durable_handle_reconnect_v2 *buf;
>> +
>> + buf = kzalloc(sizeof(struct create_durable_handle_reconnect_v2),
>> + GFP_KERNEL);
>> + if (!buf)
>> + return NULL;
>> +
>> + buf->ccontext.DataOffset =
>> + cpu_to_le16(offsetof(struct create_durable_handle_reconnect_v2,
>> + dcontext));
>> + buf->ccontext.DataLength =
>> + cpu_to_le32(sizeof(struct durable_reconnect_context_v2));
>> + buf->ccontext.NameOffset =
>> + cpu_to_le16(offsetof(struct create_durable_handle_reconnect_v2,
>> + Name));
>> + buf->ccontext.NameLength = cpu_to_le16(4);
>> +
>> + buf->dcontext.Fid.PersistentFileId = fid->persistent_fid;
>> + buf->dcontext.Fid.VolatileFileId = fid->volatile_fid;
>> + buf->dcontext.Flags = cpu_to_le32(SMB2_DHANDLE_FLAG_PERSISTENT);
>> + memcpy(buf->dcontext.CreateGuid, fid->create_guid, 16);
>> +
>> + /* SMB2_CREATE_DURABLE_HANDLE_RECONNECT_V2 is "DH2C" */
>> + buf->Name[0] = 'D';
>> + buf->Name[1] = 'H';
>> + buf->Name[2] = '2';
>> + buf->Name[3] = 'C';
>> + return buf;
>> +}
>> +
>> static __u8
>> parse_lease_state(struct TCP_Server_Info *server, struct smb2_create_rsp *rsp,
>> unsigned int *epoch)
>> @@ -1174,6 +1236,48 @@ add_durable_context(struct kvec *iov, unsigned int *num_iovec,
>> return 0;
>> }
>>
>> +static int
>> +add_durable_v2_context(struct kvec *iov, unsigned int *num_iovec,
>> + struct cifs_open_parms *oparms)
>> +{
>> + struct smb2_create_req *req = iov[0].iov_base;
>> + unsigned int num = *num_iovec;
>> +
>> + iov[num].iov_base = create_durable_v2_buf(oparms->fid);
>> + if (iov[num].iov_base == NULL)
>> + return -ENOMEM;
>> + iov[num].iov_len = sizeof(struct create_durable_v2);
>> + if (!req->CreateContextsOffset)
>> + req->CreateContextsOffset =
>> + cpu_to_le32(sizeof(struct smb2_create_req) - 4 +
>> + iov[1].iov_len);
>> + le32_add_cpu(&req->CreateContextsLength, sizeof(struct create_durable_v2));
>> + inc_rfc1001_len(&req->hdr, sizeof(struct create_durable_v2));
>> + *num_iovec = num + 1;
>> + return 0;
>> +}
>> +
>> +static int
>> +add_durable_reconnect_v2_context(struct kvec *iov, unsigned int *num_iovec,
>> + struct cifs_open_parms *oparms)
>> +{
>> + struct smb2_create_req *req = iov[0].iov_base;
>> + unsigned int num = *num_iovec;
>> +
>> + iov[num].iov_base = create_reconnect_durable_v2_buf(oparms->fid);
>> + if (iov[num].iov_base == NULL)
>> + return -ENOMEM;
>> + iov[num].iov_len = sizeof(struct create_durable_handle_reconnect_v2);
>> + if (!req->CreateContextsOffset)
>> + req->CreateContextsOffset =
>> + cpu_to_le32(sizeof(struct smb2_create_req) - 4 +
>> + iov[1].iov_len);
>> + le32_add_cpu(&req->CreateContextsLength, sizeof(struct create_durable_handle_reconnect_v2));
>> + inc_rfc1001_len(&req->hdr, sizeof(struct create_durable_handle_reconnect_v2));
>> + *num_iovec = num + 1;
>> + return 0;
>> +}
>> +
>> int
>> SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
>> __u8 *oplock, struct smb2_file_all_info *buf,
>> @@ -1272,7 +1376,15 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
>> ccontext->Next =
>> cpu_to_le32(server->vals->create_lease_size);
>> }
>> - rc = add_durable_context(iov, &num_iovecs, oparms);
>> + if (tcon->use_persistent) {
>> + if (oparms->reconnect)
>> + rc = add_durable_reconnect_v2_context(iov,
>> + &num_iovecs, oparms);
>> + else
>> + rc = add_durable_v2_context(iov, &num_iovecs,
>> + oparms);
>> + } else
>> + rc = add_durable_context(iov, &num_iovecs, oparms);
>
> I think it will be better to incapsulate this if statements into
> add_durable_context() function to leave SMB2_open() code more generic.
>
>> if (rc) {
>> cifs_small_buf_release(req);
>> kfree(copy_path);
>> diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
>> index b26da75..a939526 100644
>> --- a/fs/cifs/smb2pdu.h
>> +++ b/fs/cifs/smb2pdu.h
>> @@ -590,6 +590,36 @@ struct create_durable {
>> } Data;
>> } __packed;
>>
>> +/* Flags */
>> +#define SMB2_DHANDLE_FLAG_PERSISTENT 0x00000002
>> +struct durable_context_v2 {
>> + __le32 Timeout;
>> + __le32 Flags;
>> + __u64 Reserved;
>> + __u8 CreateGuid[16];
>> +} __packed;
>> +
>> +struct create_durable_v2 {
>> + struct create_context ccontext;
>> + __u8 Name[8];
>> + struct durable_context_v2 dcontext;
>> +} __packed;
>> +
>> +struct durable_reconnect_context_v2 {
>> + struct {
>> + __u64 PersistentFileId;
>> + __u64 VolatileFileId;
>> + } Fid;
>> + __u8 CreateGuid[16];
>> + __le32 Flags; /* see above DHANDLE_FLAG_PERSISTENT */
>> +} __packed;
>> +
>> +struct create_durable_handle_reconnect_v2 {
>> + struct create_context ccontext;
>> + __u8 Name[8];
>> + struct durable_reconnect_context_v2 dcontext;
>> +} __packed;
>> +
>> #define COPY_CHUNK_RES_KEY_SIZE 24
>> struct resume_key_req {
>> char ResumeKey[COPY_CHUNK_RES_KEY_SIZE];
>> --
>> 1.9.1
>>
>> --
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>
> Other than the note above the patch looks good.
>
> --
> Best regards,
> Pavel Shilovsky.
--
Thanks,
Steve
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