cifs: cache FILE_ALL_INFO for the shared root handle

When we open the shared root handle also ask for FILE_ALL_INFORMATION since
we can do this at zero cost as part of a compound.
Cache this information as long as the lease is held and return and serve any
future requests from cache.

This allows us to serve "stat /<mountpoint>" directly from cache and avoid
a network roundtrip.  Since clients often want to do this quite a lot
this improve performance slightly.

As an example: xfstest generic/533 performs 43 stat operations on the root
of the share while it is run. Which are eliminated with this patch.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/cifsglob.h  |   3 ++
 fs/cifs/smb2inode.c |  15 ++++---
 fs/cifs/smb2ops.c   | 113 +++++++++++++++++++++++++++++++++++++++++++---------
 fs/cifs/smb2pdu.c   |  12 +++---
 fs/cifs/smb2proto.h |   3 ++
 5 files changed, 118 insertions(+), 28 deletions(-)

пн, 11 мар. 2019 г. в 20:59, Ronnie Sahlberg <lsahlber@redhat.com>:
>
> When we open the shared root handle also ask for FILE_ALL_INFORMATION since
> we can do this at zero cost as part of a compound.
> Cache this information as long as the lease is held and return and serve any
> future requests from cache.
>
> This allows us to serve "stat /<mountpoint>" directly from cache and avoid
> a network roundtrip.  Since clients often want to do this quite a lot
> this improve performance slightly.
>
> As an example: xfstest generic/533 performs 43 stat operations on the root
> of the share while it is run. Which are eliminated with this patch.
>
> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
>  fs/cifs/cifsglob.h  |   3 ++
>  fs/cifs/smb2inode.c |  15 ++++---
>  fs/cifs/smb2ops.c   | 113 +++++++++++++++++++++++++++++++++++++++++++---------
>  fs/cifs/smb2pdu.c   |  12 +++---
>  fs/cifs/smb2proto.h |   3 ++
>  5 files changed, 118 insertions(+), 28 deletions(-)
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index f293e052e351..b8360ca221eb 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -962,11 +962,14 @@ cap_unix(struct cifs_ses *ses)
>
>  struct cached_fid {
>         bool is_valid:1;        /* Do we have a useable root fid */
> +       bool file_all_info_is_valid:1;
> +
>         struct kref refcount;
>         struct cifs_fid *fid;
>         struct mutex fid_mutex;
>         struct cifs_tcon *tcon;
>         struct work_struct lease_break;
> +       struct smb2_file_all_info file_all_info;
>  };
>
>  /*
> diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c
> index 01a76bccdb8d..b6e07e2eed10 100644
> --- a/fs/cifs/smb2inode.c
> +++ b/fs/cifs/smb2inode.c
> @@ -309,12 +309,17 @@ smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
>                 rc = open_shroot(xid, tcon, &fid);
>                 if (rc)
>                         goto out;
> -               rc = SMB2_query_info(xid, tcon, fid.persistent_fid,
> -                                    fid.volatile_fid, smb2_data);
> +
> +               if (tcon->crfid.file_all_info_is_valid) {
> +                       move_smb2_info_to_cifs(data,
> +                                              &tcon->crfid.file_all_info);
> +               } else {
> +                       rc = SMB2_query_info(xid, tcon, fid.persistent_fid,
> +                                            fid.volatile_fid, smb2_data);
> +                       if (!rc)
> +                               move_smb2_info_to_cifs(data, smb2_data);
> +               }
>                 close_shroot(&tcon->crfid);
> -               if (rc)
> -                       goto out;
> -               move_smb2_info_to_cifs(data, smb2_data);
>                 goto out;
>         }
>
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 085e91436da7..5f2487e88c9d 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -619,6 +619,7 @@ smb2_close_cached_fid(struct kref *ref)
>                 SMB2_close(0, cfid->tcon, cfid->fid->persistent_fid,
>                            cfid->fid->volatile_fid);
>                 cfid->is_valid = false;
> +               cfid->file_all_info_is_valid = false;
>         }
>  }
>
> @@ -643,9 +644,18 @@ smb2_cached_lease_break(struct work_struct *work)
>   */
>  int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
>  {
> -       struct cifs_open_parms oparams;
> -       int rc;
> -       __le16 srch_path = 0; /* Null - since an open of top of share */
> +       struct cifs_ses *ses = tcon->ses;
> +       struct TCP_Server_Info *server = ses->server;
> +       struct cifs_open_parms oparms;
> +       struct smb2_create_rsp *o_rsp = NULL;
> +       struct smb2_query_info_rsp *qi_rsp = NULL;
> +       int resp_buftype[2];
> +       struct smb_rqst rqst[2];
> +       struct kvec rsp_iov[2];
> +       struct kvec open_iov[SMB2_CREATE_IOV_SIZE];
> +       struct kvec qi_iov[1];
> +       int rc, flags = 0;
> +       __le16 utf16_path = 0; /* Null - since an open of top of share */
>         u8 oplock = SMB2_OPLOCK_LEVEL_II;
>
>         mutex_lock(&tcon->crfid.fid_mutex);
> @@ -657,22 +667,89 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
>                 return 0;
>         }
>
> -       oparams.tcon = tcon;
> -       oparams.create_options = 0;
> -       oparams.desired_access = FILE_READ_ATTRIBUTES;
> -       oparams.disposition = FILE_OPEN;
> -       oparams.fid = pfid;
> -       oparams.reconnect = false;
> -
> -       rc = SMB2_open(xid, &oparams, &srch_path, &oplock, NULL, NULL, NULL);
> -       if (rc == 0) {
> -               memcpy(tcon->crfid.fid, pfid, sizeof(struct cifs_fid));
> -               tcon->crfid.tcon = tcon;
> -               tcon->crfid.is_valid = true;
> -               kref_init(&tcon->crfid.refcount);
> -               kref_get(&tcon->crfid.refcount);
> -       }
> +       if (smb3_encryption_required(tcon))
> +               flags |= CIFS_TRANSFORM_REQ;
> +
> +       memset(rqst, 0, sizeof(rqst));
> +       resp_buftype[0] = resp_buftype[1] = CIFS_NO_BUFFER;
> +       memset(rsp_iov, 0, sizeof(rsp_iov));
> +
> +       /* Open */
> +       memset(&open_iov, 0, sizeof(open_iov));
> +       rqst[0].rq_iov = open_iov;
> +       rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE;
> +
> +       oparms.tcon = tcon;
> +       oparms.create_options = 0;
> +       oparms.desired_access = FILE_READ_ATTRIBUTES;
> +       oparms.disposition = FILE_OPEN;
> +       oparms.fid = pfid;
> +       oparms.reconnect = false;
> +
> +       rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, &utf16_path);
> +       if (rc)
> +               goto oshr_exit;
> +       smb2_set_next_command(tcon, &rqst[0]);
> +
> +       memset(&qi_iov, 0, sizeof(qi_iov));
> +       rqst[1].rq_iov = qi_iov;
> +       rqst[1].rq_nvec = 1;
> +
> +       rc = SMB2_query_info_init(tcon, &rqst[1], COMPOUND_FID,
> +                                 COMPOUND_FID, FILE_ALL_INFORMATION,
> +                                 SMB2_O_INFO_FILE, 0,
> +                                 sizeof(struct smb2_file_all_info) +
> +                                 PATH_MAX * 2, 0, NULL);
> +       if (rc)
> +               goto oshr_exit;
> +
> +       smb2_set_related(&rqst[1]);
> +
> +       rc = compound_send_recv(xid, ses, flags, 2, rqst,
> +                               resp_buftype, rsp_iov);
> +       if (rc)
> +               goto oshr_exit;
> +
> +       o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base;
> +       oparms.fid->persistent_fid = o_rsp->PersistentFileId;
> +       oparms.fid->volatile_fid = o_rsp->VolatileFileId;
> +#ifdef CONFIG_CIFS_DEBUG2
> +       oparms.fid->mid = le64_to_cpu(o_rsp->sync_hdr.MessageId);
> +#endif /* CIFS_DEBUG2 */
> +
> +       if (o_rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE)
> +               oplock = smb2_parse_lease_state(server, o_rsp,
> +                                               &oparms.fid->epoch,
> +                                               oparms.fid->lease_key);
> +       else
> +               goto oshr_exit;
> +
> +
> +       memcpy(tcon->crfid.fid, pfid, sizeof(struct cifs_fid));
> +       tcon->crfid.tcon = tcon;
> +       tcon->crfid.is_valid = true;
> +       kref_init(&tcon->crfid.refcount);
> +       kref_get(&tcon->crfid.refcount);
> +
> +
> +       qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base;
> +       if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info))
> +               goto oshr_exit;
> +       rc = smb2_validate_and_copy_iov(
> +                               le16_to_cpu(qi_rsp->OutputBufferOffset),
> +                               sizeof(struct smb2_file_all_info),
> +                               &rsp_iov[1], sizeof(struct smb2_file_all_info),
> +                               (char *)&tcon->crfid.file_all_info);
> +       if (rc)
> +               goto oshr_exit;
> +       tcon->crfid.file_all_info_is_valid = 1;
> +
> + oshr_exit:
>         mutex_unlock(&tcon->crfid.fid_mutex);
> +       SMB2_open_free(&rqst[0]);
> +       SMB2_query_info_free(&rqst[1]);
> +       free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);
> +       free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
>         return rc;
>  }
>
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 60fbe306f604..cfe9fe41ccf5 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -1797,9 +1797,10 @@ create_reconnect_durable_buf(struct cifs_fid *fid)
>         return buf;
>  }
>
> -static __u8
> -parse_lease_state(struct TCP_Server_Info *server, struct smb2_create_rsp *rsp,
> -                 unsigned int *epoch, char *lease_key)
> +__u8
> +smb2_parse_lease_state(struct TCP_Server_Info *server,
> +                      struct smb2_create_rsp *rsp,
> +                      unsigned int *epoch, char *lease_key)
>  {
>         char *data_offset;
>         struct create_context *cc;
> @@ -2456,8 +2457,9 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
>         }
>
>         if (rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE)
> -               *oplock = parse_lease_state(server, rsp, &oparms->fid->epoch,
> -                                           oparms->fid->lease_key);
> +               *oplock = smb2_parse_lease_state(server, rsp,
> +                                                &oparms->fid->epoch,
> +                                                oparms->fid->lease_key);
>         else
>                 *oplock = rsp->OplockLevel;
>  creat_exit:
> diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
> index 87733b27a65f..72cc563c32fe 100644
> --- a/fs/cifs/smb2proto.h
> +++ b/fs/cifs/smb2proto.h
> @@ -223,6 +223,9 @@ extern int smb3_validate_negotiate(const unsigned int, struct cifs_tcon *);
>
>  extern enum securityEnum smb2_select_sectype(struct TCP_Server_Info *,
>                                         enum securityEnum);
> +extern __u8 smb2_parse_lease_state(struct TCP_Server_Info *server,
> +                                  struct smb2_create_rsp *rsp,
> +                                  unsigned int *epoch, char *lease_key);
>  extern int smb3_encryption_required(const struct cifs_tcon *tcon);
>  extern int smb2_validate_iov(unsigned int offset, unsigned int buffer_length,
>                              struct kvec *iov, unsigned int min_buf_size);
> --
> 2.13.6
>

Looks good now.

Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

--
Best regards,
Pavel Shilovsky