Fix 20 second hang on some deletes of reopened file due to semaphore conflict...

Fix 20 second hang on some deletes of reopened file due to semaphore conflict with vfs_delete on i_sem

fs/cifs/CHANGES

@@ -2,7 +2,9 @@ Version 1.06
 ------------
 Send NTCreateX with ATTR_POSIX if Linux/Unix extensions negotiated with server.
 This allows files that differ only in case and improves performance of file
-creation and file open to such servers.
+creation and file open to such servers.  Fix semaphore conflict which causes 
+slow delete of open file to Samba (which unfortunately can cause an oplock
+break to self while vfs_unlink held i_sem) which can hang for 20 seconds.
 
 Version 1.05
 ------------

fs/cifs/cifsencrypt.c

@@ -74,7 +74,7 @@ int cifs_sign_smb(struct smb_hdr * cifs_pdu, struct cifsSesInfo * ses,
 
 	rc = cifs_calculate_signature(cifs_pdu, ses->mac_signing_key,smb_signature);
 	if(rc)
-                memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
+		memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
 	else
 		memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8);
 
@@ -88,15 +88,15 @@ int cifs_verify_signature(struct smb_hdr * cifs_pdu, const char * mac_key,
 	char server_response_sig[8];
 	char what_we_think_sig_should_be[20];
 
-        if((cifs_pdu == NULL) || (mac_key == NULL))
-                return -EINVAL;
+	if((cifs_pdu == NULL) || (mac_key == NULL))
+		return -EINVAL;
 
 	if (cifs_pdu->Command == SMB_COM_NEGOTIATE)
 		return 0;
 
 	if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) {
 		struct smb_com_lock_req * pSMB = (struct smb_com_lock_req *)cifs_pdu;
-	        if(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
+	    if(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE)
 			return 0;
 	}
 
@@ -113,10 +113,10 @@ int cifs_verify_signature(struct smb_hdr * cifs_pdu, const char * mac_key,
 		its signature against what the server sent */
 	memcpy(server_response_sig,cifs_pdu->Signature.SecuritySignature,8);
 
-        cifs_pdu->Signature.Sequence.SequenceNumber = expected_sequence_number;
-        cifs_pdu->Signature.Sequence.Reserved = 0;
+	cifs_pdu->Signature.Sequence.SequenceNumber = expected_sequence_number;
+	cifs_pdu->Signature.Sequence.Reserved = 0;
 
-        rc = cifs_calculate_signature(cifs_pdu, mac_key,
+	rc = cifs_calculate_signature(cifs_pdu, mac_key,
 		what_we_think_sig_should_be);
 
 	if(rc)
@@ -167,19 +167,19 @@ int CalcNTLMv2_partial_mac_key(struct cifsSesInfo * ses, struct nls_table * nls_
 		return -EINVAL;
   
 	ucase_buf = kmalloc((MAX_USERNAME_SIZE+1), GFP_KERNEL);
-        unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
+	unicode_buf = kmalloc((MAX_USERNAME_SIZE+1)*4, GFP_KERNEL);
    
 	for(i=0;i<user_name_len;i++)
 		ucase_buf[i] = nls_info->charset2upper[(int)ses->userName[i]];
 	ucase_buf[i] = 0;
-        user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
+	user_name_len = cifs_strtoUCS(unicode_buf, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 	unicode_buf[user_name_len] = 0;
 	user_name_len++;
 
-        for(i=0;i<dom_name_len;i++)
-                ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
-        ucase_buf[i] = 0;
-        dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
+	for(i=0;i<dom_name_len;i++)
+		ucase_buf[i] = nls_info->charset2upper[(int)ses->domainName[i]];
+	ucase_buf[i] = 0;
+	dom_name_len = cifs_strtoUCS(unicode_buf+user_name_len, ucase_buf, MAX_USERNAME_SIZE*2, nls_info);
 
 	unicode_buf[user_name_len + dom_name_len] = 0;
 	hmac_md5_update((const unsigned char *) unicode_buf,
@@ -200,6 +200,5 @@ void CalcNTLMv2_response(const struct cifsSesInfo * ses,char * v2_session_respon
 	hmac_md5_update(ses->server->cryptKey,8,&context);
 /*	hmac_md5_update(v2_session_response+16)client thing,8,&context); */ /* BB fix */
 
-
 	hmac_md5_final(v2_session_response,&context);
 }

fs/cifs/cifsfs.c

@@ -631,19 +631,24 @@ static int cifs_oplock_thread(void * dummyarg)
 			oplock_item = list_entry(GlobalOplock_Q.next, 
 				struct oplock_q_entry, qhead);
 			if(oplock_item) {
+				cFYI(1,("found oplock item to write out")); 
 				pTcon = oplock_item->tcon;
 				inode = oplock_item->pinode;
 				netfid = oplock_item->netfid;
 				spin_unlock(&GlobalMid_Lock);
 				DeleteOplockQEntry(oplock_item);
-				down(&inode->i_sem);
+				/* can not grab inode sem here since it would
+				deadlock when oplock received on delete 
+				since vfs_unlink holds the i_sem across
+				the call */
+				/* down(&inode->i_sem);*/
 				if (S_ISREG(inode->i_mode)) {
 					rc = filemap_fdatawrite(inode->i_mapping);
 					if(CIFS_I(inode)->clientCanCacheRead == 0)
 						invalidate_remote_inode(inode);
 				} else
 					rc = 0;
-				up(&inode->i_sem);
+				/* up(&inode->i_sem);*/
 				if (rc)
 					CIFS_I(inode)->write_behind_rc = rc;
 				cFYI(1,("Oplock flush inode %p rc %d",inode,rc));

fs/cifs/file.c

@@ -924,7 +924,6 @@ static void cifs_copy_cache_pages(struct address_space *mapping,
 			break;
 
 		page = list_entry(pages->prev, struct page, list);
-/*cERROR(1,("copy_cache_pages page %p index %ld data %p",page,page->index,data));*/ /* BB removeme */
 		list_del(&page->list);
 
 		if (add_to_page_cache(page, mapping, page->index, GFP_KERNEL)) {
@@ -1009,18 +1008,12 @@ cifs_readpages(struct file *file, struct address_space *mapping,
 				break; 
 			}
 		}
-/*		cERROR(1,("ended with contig_pages %d since expected_index %d not matched",contig_pages,expected_index)); */
 		if(contig_pages + i >  num_pages) {
-/*			cERROR(1,("reducing contig_pages from %d with i: %d",contig_pages,i));*/
 			contig_pages = num_pages - i;
 		}
 
 		/* for reads over a certain size could initiate async read ahead */
 
-/*		cERROR(1,("Read %d pages out of %d into cache at offset %ld ",
-			contig_pages, num_pages-i, (unsigned long) offset));*/  /* BB removeme BB */
-	
-			
 		read_size = contig_pages * PAGE_CACHE_SIZE;
 		/* Read size needs to be in multiples of one page */
 		read_size = min_t(const unsigned int,read_size,cifs_sb->rsize & PAGE_CACHE_MASK);
@@ -1038,7 +1031,6 @@ cifs_readpages(struct file *file, struct address_space *mapping,
 				read_size, offset,
 				&bytes_read, &smb_read_data);
 			/* BB need to check return code here */
-/*			cERROR(1,("read size: %d bytes read: %d rc: %d",read_size,bytes_read,rc)); */ /* BB removeme BB */
 		}
 		if ((rc < 0) || (smb_read_data == NULL)) {
 			cERROR(1,("Read error in readpages: %d",rc));