[CIFS] Add posix (advisory) byte range locking support to cifs client

Samba (version 3) server support for this is also currently being
done.  This client code is in an experimental path (requires enabling
/proc/fs/cifs/Experimental) while it is being tested.

Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 0ddd97b1d87d..fea32e395cc6 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1353,6 +1353,84 @@ CIFSSMBLock(const int xid, struct cifsTconInfo *tcon,
 }
 
 int
+CIFSSMBPosixLock(const int xid, struct cifsTconInfo *tcon,
+                const __u16 smb_file_id, const int get_flag, const __u64 len,
+                const __u64 lkoffset, const __u16 lock_type, const int waitFlag)
+{
+        struct smb_com_transaction2_sfi_req *pSMB  = NULL;
+        struct smb_com_transaction2_sfi_rsp *pSMBr = NULL;
+        char *data_offset;
+        struct cifs_posix_lock *parm_data;
+        int rc = 0;
+        int bytes_returned = 0;
+        __u16 params, param_offset, offset, byte_count, count;
+
+        cFYI(1, ("Posix Lock"));
+        rc = small_smb_init(SMB_COM_TRANSACTION2, 15, tcon, (void **) &pSMB);
+
+        if (rc)
+                return rc;
+
+        pSMBr = (struct smb_com_transaction2_sfi_rsp *)pSMB;
+
+        params = 6; 
+        pSMB->MaxSetupCount = 0;
+        pSMB->Reserved = 0;
+        pSMB->Flags = 0;
+        pSMB->Timeout = 0;
+        pSMB->Reserved2 = 0;
+        param_offset = offsetof(struct smb_com_transaction2_sfi_req, Fid) - 4;
+        offset = param_offset + params;
+
+        data_offset = (char *) (&pSMB->hdr.Protocol) + offset;
+
+        count = sizeof(struct cifs_posix_lock);
+        pSMB->MaxParameterCount = cpu_to_le16(2);
+        pSMB->MaxDataCount = cpu_to_le16(1000); /* BB find max SMB PDU from sess */
+        pSMB->SetupCount = 1;
+        pSMB->Reserved3 = 0;
+        if(get_flag)
+                pSMB->SubCommand = cpu_to_le16(TRANS2_QUERY_FILE_INFORMATION);
+        else
+                pSMB->SubCommand = cpu_to_le16(TRANS2_SET_FILE_INFORMATION);
+        byte_count = 3 /* pad */  + params + count;
+        pSMB->DataCount = cpu_to_le16(count);
+        pSMB->ParameterCount = cpu_to_le16(params);
+        pSMB->TotalDataCount = pSMB->DataCount;
+        pSMB->TotalParameterCount = pSMB->ParameterCount;
+        pSMB->ParameterOffset = cpu_to_le16(param_offset);
+        parm_data = (struct cifs_posix_lock *) 
+                        (((char *) &pSMB->hdr.Protocol) + offset);
+
+        parm_data->lock_type = cpu_to_le16(lock_type);
+        if(waitFlag)
+                parm_data->lock_flags = 1;
+        parm_data->pid = cpu_to_le32(current->tgid);
+        parm_data->start = lkoffset;
+        parm_data->length = len;  /* normalize negative numbers */
+
+        pSMB->DataOffset = cpu_to_le16(offset);
+        pSMB->InformationLevel = cpu_to_le16(SMB_SET_POSIX_LOCK);
+        pSMB->Reserved4 = 0;
+        pSMB->hdr.smb_buf_length += byte_count;
+        pSMB->ByteCount = cpu_to_le16(byte_count);
+        rc = SendReceive(xid, tcon->ses, (struct smb_hdr *) pSMB,
+                        (struct smb_hdr *) pSMBr, &bytes_returned, 0);
+        if (rc) {
+                cFYI(1, ("Send error in Posix Lock = %d", rc));
+        }
+
+        if (pSMB)
+                cifs_small_buf_release(pSMB);
+
+        /* Note: On -EAGAIN error only caller can retry on handle based calls
+           since file handle passed in no longer valid */
+
+        return rc;
+}
+
+
+int
 CIFSSMBClose(const int xid, struct cifsTconInfo *tcon, int smb_file_id)
 {
         int rc = 0;