cifs: add support for SEEK_DATA and SEEK_HOLE

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/cifsfs.c   |  9 ++++++
 fs/cifs/cifsglob.h |  2 ++
 fs/cifs/smb2ops.c  | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 99 insertions(+)

merged into cifs-2.6.git for-next

On Tue, May 14, 2019 at 4:33 PM Ronnie Sahlberg <lsahlber@redhat.com> wrote:
>
> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
>  fs/cifs/cifsfs.c   |  9 ++++++
>  fs/cifs/cifsglob.h |  2 ++
>  fs/cifs/smb2ops.c  | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 99 insertions(+)
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index b1a5fcfa3ce1..75fef9fb78d8 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -878,6 +878,9 @@ static ssize_t cifs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
>
>  static loff_t cifs_llseek(struct file *file, loff_t offset, int whence)
>  {
> +       struct cifsFileInfo *cfile = file->private_data;
> +       struct cifs_tcon *tcon;
> +
>         /*
>          * whence == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
>          * the cached file length
> @@ -909,6 +912,12 @@ static loff_t cifs_llseek(struct file *file, loff_t offset, int whence)
>                 if (rc < 0)
>                         return (loff_t)rc;
>         }
> +       if (cfile && cfile->tlink) {
> +               tcon = tlink_tcon(cfile->tlink);
> +               if (tcon->ses->server->ops->llseek)
> +                       return tcon->ses->server->ops->llseek(file, tcon,
> +                                                             offset, whence);
> +       }
>         return generic_file_llseek(file, offset, whence);
>  }
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 33c251b408aa..334ff5f9c3f3 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -497,6 +497,8 @@ struct smb_version_operations {
>         /* version specific fiemap implementation */
>         int (*fiemap)(struct cifs_tcon *tcon, struct cifsFileInfo *,
>                       struct fiemap_extent_info *, u64, u64);
> +       /* version specific llseek implementation */
> +       loff_t (*llseek)(struct file *, struct cifs_tcon *, loff_t, int);
>  };
>
>  struct smb_version_values {
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 542b50c0b292..e921e6511728 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -2922,6 +2922,90 @@ static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
>         return rc;
>  }
>
> +static loff_t smb3_llseek(struct file *file, struct cifs_tcon *tcon, loff_t offset, int whence)
> +{
> +       struct cifsFileInfo *wrcfile, *cfile = file->private_data;
> +       struct cifsInodeInfo *cifsi;
> +       struct inode *inode;
> +       int rc = 0;
> +       struct file_allocated_range_buffer in_data, *out_data = NULL;
> +       u32 out_data_len;
> +       unsigned int xid;
> +
> +       if (whence != SEEK_HOLE && whence != SEEK_DATA)
> +               return generic_file_llseek(file, offset, whence);
> +
> +       inode = d_inode(cfile->dentry);
> +       cifsi = CIFS_I(inode);
> +
> +       if (offset < 0 || offset >= i_size_read(inode))
> +               return -ENXIO;
> +
> +       xid = get_xid();
> +       /*
> +        * We need to be sure that all dirty pages are written as they
> +        * might fill holes on the server.
> +        * Note that we also MUST flush any written pages since at least
> +        * some servers (Windows2016) will not reflect recent writes in
> +        * QUERY_ALLOCATED_RANGES until SMB2_flush is called.
> +        */
> +       wrcfile = find_writable_file(cifsi, false);
> +       if (wrcfile) {
> +               filemap_write_and_wait(inode->i_mapping);
> +               smb2_flush_file(xid, tcon, &wrcfile->fid);
> +               cifsFileInfo_put(wrcfile);
> +       }
> +
> +       if (!(cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE)) {
> +               if (whence == SEEK_HOLE)
> +                       offset = i_size_read(inode);
> +               goto lseek_exit;
> +       }
> +
> +       in_data.file_offset = cpu_to_le64(offset);
> +       in_data.length = cpu_to_le64(i_size_read(inode));
> +
> +       rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
> +                       cfile->fid.volatile_fid,
> +                       FSCTL_QUERY_ALLOCATED_RANGES, true,
> +                       (char *)&in_data, sizeof(in_data),
> +                       sizeof(struct file_allocated_range_buffer),
> +                       (char **)&out_data, &out_data_len);
> +       if (rc == -E2BIG)
> +               rc = 0;
> +       if (rc)
> +               goto lseek_exit;
> +
> +       if (whence == SEEK_HOLE && out_data_len == 0)
> +               goto lseek_exit;
> +
> +       if (whence == SEEK_DATA && out_data_len == 0) {
> +               rc = -ENXIO;
> +               goto lseek_exit;
> +       }
> +
> +       if (out_data_len < sizeof(struct file_allocated_range_buffer)) {
> +               rc = -EINVAL;
> +               goto lseek_exit;
> +       }
> +       if (whence == SEEK_DATA) {
> +               offset = le64_to_cpu(out_data->file_offset);
> +               goto lseek_exit;
> +       }
> +       if (offset < le64_to_cpu(out_data->file_offset))
> +               goto lseek_exit;
> +
> +       offset = le64_to_cpu(out_data->file_offset) + le64_to_cpu(out_data->length);
> +
> + lseek_exit:
> +       free_xid(xid);
> +       kfree(out_data);
> +       if (!rc)
> +               return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
> +       else
> +               return rc;
> +}
> +
>  static int smb3_fiemap(struct cifs_tcon *tcon,
>                        struct cifsFileInfo *cfile,
>                        struct fiemap_extent_info *fei, u64 start, u64 len)
> @@ -4166,6 +4250,7 @@ struct smb_version_operations smb20_operations = {
>         .ioctl_query_info = smb2_ioctl_query_info,
>         .make_node = smb2_make_node,
>         .fiemap = smb3_fiemap,
> +       .llseek = smb3_llseek,
>  };
>
>  struct smb_version_operations smb21_operations = {
> @@ -4266,6 +4351,7 @@ struct smb_version_operations smb21_operations = {
>         .ioctl_query_info = smb2_ioctl_query_info,
>         .make_node = smb2_make_node,
>         .fiemap = smb3_fiemap,
> +       .llseek = smb3_llseek,
>  };
>
>  struct smb_version_operations smb30_operations = {
> @@ -4375,6 +4461,7 @@ struct smb_version_operations smb30_operations = {
>         .ioctl_query_info = smb2_ioctl_query_info,
>         .make_node = smb2_make_node,
>         .fiemap = smb3_fiemap,
> +       .llseek = smb3_llseek,
>  };
>
>  struct smb_version_operations smb311_operations = {
> @@ -4485,6 +4572,7 @@ struct smb_version_operations smb311_operations = {
>         .ioctl_query_info = smb2_ioctl_query_info,
>         .make_node = smb2_make_node,
>         .fiemap = smb3_fiemap,
> +       .llseek = smb3_llseek,
>  };
>
>  struct smb_version_values smb20_values = {
> --
> 2.13.6
>