cifs: Fix potential softlockups while refreshing DFS cache
commit84a1f5b1cc
upstream. We used to skip reconnects on all SMB2_IOCTL commands due to SMB3+ FSCTL_VALIDATE_NEGOTIATE_INFO - which made sense since we're still establishing a SMB session. However, when refresh_cache_worker() calls smb2_get_dfs_refer() and we're under reconnect, SMB2_ioctl() will not be able to get a proper status error (e.g. -EHOSTDOWN in case we failed to reconnect) but an -EAGAIN from cifs_send_recv() thus looping forever in refresh_cache_worker(). Fixes:e99c63e4d8
("SMB3: Fix deadlock in validate negotiate hits reconnect") Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Suggested-by: Aurelien Aptel <aaptel@suse.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -252,7 +252,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon)
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if (tcon == NULL)
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return 0;
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if (smb2_command == SMB2_TREE_CONNECT || smb2_command == SMB2_IOCTL)
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if (smb2_command == SMB2_TREE_CONNECT)
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return 0;
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if (tcon->tidStatus == CifsExiting) {
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@ -426,16 +426,9 @@ fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon, void *buf,
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* SMB information in the SMB header. If the return code is zero, this
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* function must have filled in request_buf pointer.
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*/
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static int
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smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
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void **request_buf, unsigned int *total_len)
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static int __smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
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void **request_buf, unsigned int *total_len)
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{
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int rc;
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rc = smb2_reconnect(smb2_command, tcon);
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if (rc)
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return rc;
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/* BB eventually switch this to SMB2 specific small buf size */
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if (smb2_command == SMB2_SET_INFO)
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*request_buf = cifs_buf_get();
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@ -456,7 +449,31 @@ smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
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cifs_stats_inc(&tcon->num_smbs_sent);
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}
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return rc;
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return 0;
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}
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static int smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
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void **request_buf, unsigned int *total_len)
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{
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int rc;
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rc = smb2_reconnect(smb2_command, tcon);
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if (rc)
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return rc;
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return __smb2_plain_req_init(smb2_command, tcon, request_buf,
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total_len);
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}
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static int smb2_ioctl_req_init(u32 opcode, struct cifs_tcon *tcon,
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void **request_buf, unsigned int *total_len)
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{
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/* Skip reconnect only for FSCTL_VALIDATE_NEGOTIATE_INFO IOCTLs */
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if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO) {
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return __smb2_plain_req_init(SMB2_IOCTL, tcon, request_buf,
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total_len);
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}
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return smb2_plain_req_init(SMB2_IOCTL, tcon, request_buf, total_len);
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}
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/* For explanation of negotiate contexts see MS-SMB2 section 2.2.3.1 */
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@ -2661,7 +2678,7 @@ SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
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int rc;
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char *in_data_buf;
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rc = smb2_plain_req_init(SMB2_IOCTL, tcon, (void **) &req, &total_len);
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rc = smb2_ioctl_req_init(opcode, tcon, (void **) &req, &total_len);
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if (rc)
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return rc;
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