Re: [PATCH v3] cifs: Remove intermediate object of failed create reparse call

[Steve French]

tentatively merged into cifs-2.6.git pending review and testing

On Mon, Sep 30, 2024 at 3:28 PM Pali Rohár <pali@xxxxxxxxxx> wrote:
>
> If CREATE was successful but SMB2_OP_SET_REPARSE failed then remove the
> intermediate object created by CREATE. Otherwise empty object stay on the
> server when reparse call failed.
>
> This ensures that if the creating of special files is unsupported by the
> server then no empty file stay on the server as a result of unsupported
> operation.
>
> Fixes: 102466f303ff ("smb: client: allow creating special files via reparse points")
> Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> ---
> Changes in v3:
> * Check if iov_base and out_buftype are valid before derefrencing iov_base
> Changes in v2:
> * Increase out_buftype[] and out_iov[] members from 2 to 4 as required by smb2_compound_op
> * Call free_rsp_buf() for all members of out_buftype[]/out_iov[]
> ---
>  fs/smb/client/smb2inode.c | 24 ++++++++++++++++++++++--
>  1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
> index 11a1c53c64e0..a6dab60e2c01 100644
> --- a/fs/smb/client/smb2inode.c
> +++ b/fs/smb/client/smb2inode.c
> @@ -1205,9 +1205,12 @@ struct inode *smb2_get_reparse_inode(struct cifs_open_info_data *data,
>         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
>         struct cifsFileInfo *cfile;
>         struct inode *new = NULL;
> +       int out_buftype[4] = {};
> +       struct kvec out_iov[4] = {};
>         struct kvec in_iov[2];
>         int cmds[2];
>         int rc;
> +       int i;
>
>         oparms = CIFS_OPARMS(cifs_sb, tcon, full_path,
>                              SYNCHRONIZE | DELETE |
> @@ -1228,7 +1231,7 @@ struct inode *smb2_get_reparse_inode(struct cifs_open_info_data *data,
>                 cmds[1] = SMB2_OP_POSIX_QUERY_INFO;
>                 cifs_get_writable_path(tcon, full_path, FIND_WR_ANY, &cfile);
>                 rc = smb2_compound_op(xid, tcon, cifs_sb, full_path, &oparms,
> -                                     in_iov, cmds, 2, cfile, NULL, NULL, NULL);
> +                                     in_iov, cmds, 2, cfile, out_iov, out_buftype, NULL);
>                 if (!rc) {
>                         rc = smb311_posix_get_inode_info(&new, full_path,
>                                                          data, sb, xid);
> @@ -1237,12 +1240,29 @@ struct inode *smb2_get_reparse_inode(struct cifs_open_info_data *data,
>                 cmds[1] = SMB2_OP_QUERY_INFO;
>                 cifs_get_writable_path(tcon, full_path, FIND_WR_ANY, &cfile);
>                 rc = smb2_compound_op(xid, tcon, cifs_sb, full_path, &oparms,
> -                                     in_iov, cmds, 2, cfile, NULL, NULL, NULL);
> +                                     in_iov, cmds, 2, cfile, out_iov, out_buftype, NULL);
>                 if (!rc) {
>                         rc = cifs_get_inode_info(&new, full_path,
>                                                  data, sb, xid, NULL);
>                 }
>         }
> +
> +
> +       /*
> +        * If CREATE was successful but SMB2_OP_SET_REPARSE failed then
> +        * remove the intermediate object created by CREATE. Otherwise
> +        * empty object stay on the server when reparse call failed.
> +        */
> +       if (rc &&
> +           out_iov[0].iov_base != NULL && out_buftype[0] != CIFS_NO_BUFFER &&
> +           ((struct smb2_hdr *)out_iov[0].iov_base)->Status == STATUS_SUCCESS &&
> +           (out_iov[1].iov_base == NULL || out_buftype[1] == CIFS_NO_BUFFER ||
> +            ((struct smb2_hdr *)out_iov[1].iov_base)->Status != STATUS_SUCCESS))
> +               smb2_unlink(xid, tcon, full_path, cifs_sb, NULL);
> +
> +       for (i = 0; i < ARRAY_SIZE(out_buftype); i++)
> +               free_rsp_buf(out_buftype[i], out_iov[i].iov_base);
> +
>         return rc ? ERR_PTR(rc) : new;
>  }
>
> --
> 2.20.1
>
>


-- 
Thanks,

Steve