[CIFS] When file is deleted locally but later recreated on the server

fix cifs negative dentries so they are freed faster (not requiring
umount or readdir e.g.) so the client recognizes the new file on
the server more quickly.
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/CHANGES

 Version 1.39
 ------------
-Defer close of a file handle slightly if pending writes depend on that file handle
+Defer close of a file handle slightly if pending writes depend on that handle
 (this reduces the EBADF bad file handle errors that can be logged under heavy
 stress on writes). Modify cifs Kconfig options to expose CONFIG_CIFS_STATS2 
-Fix SFU style symlinks and mknod needed for servers which do not support the CIFS
-Unix Extensions.  Fix setfacl/getfacl on bigendian. 
+Fix SFU style symlinks and mknod needed for servers which do not support the
+CIFS Unix Extensions.  Fix setfacl/getfacl on bigendian. Timeout negative
+dentries so files that the client sees as deleted but that later get created
+on the server will be recognized.
 
 Version 1.38
 ------------

fs/cifs/dir.c

@@ -465,12 +465,20 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, struct name
 			direntry->d_op = &cifs_dentry_ops;
 		d_add(direntry, newInode);
 
-		/* since paths are not looked up by component - the parent directories are presumed to be good here */
+		/* since paths are not looked up by component - the parent 
+		   directories are presumed to be good here */
 		renew_parental_timestamps(direntry);
 
 	} else if (rc == -ENOENT) {
 		rc = 0;
+		direntry->d_time = jiffies;
+		if (pTcon->nocase)
+			direntry->d_op = &cifs_ci_dentry_ops;
+		else
+			direntry->d_op = &cifs_dentry_ops;
 		d_add(direntry, NULL);
+	/*	if it was once a directory (but how can we tell?) we could do  
+			shrink_dcache_parent(direntry); */
 	} else {
 		cERROR(1,("Error 0x%x on cifs_get_inode_info in lookup of %s",
 			   rc,full_path));
@@ -489,20 +497,19 @@ cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd)
 {
 	int isValid = 1;
 
-/*	lock_kernel(); *//* surely we do not want to lock the kernel for a whole network round trip which could take seconds */
-
 	if (direntry->d_inode) {
 		if (cifs_revalidate(direntry)) {
-			/* unlock_kernel(); */
 			return 0;
 		}
 	} else {
-		cFYI(1,
-		     ("In cifs_d_revalidate with no inode but name = %s and dentry 0x%p",
-		      direntry->d_name.name, direntry));
+		cFYI(1, ("neg dentry 0x%p name = %s",
+			 direntry, direntry->d_name.name));
+		if(time_after(jiffies, direntry->d_time + HZ) || 
+			!lookupCacheEnabled) {
+			d_drop(direntry);
+			isValid = 0;
+		} 
 	}
-
-/*    unlock_kernel(); */
 
 	return isValid;
 }

fs/cifs/inode.c

@@ -1039,16 +1039,22 @@ int cifs_revalidate(struct dentry *direntry)
 		filemap_fdatawrite(direntry->d_inode->i_mapping);
 	}
 	if (invalidate_inode) {
+	/* shrink_dcache not necessary now that cifs dentry ops
+	are exported for negative dentries */
+/*		if(S_ISDIR(direntry->d_inode->i_mode)) 
+			shrink_dcache_parent(direntry); */
+		if (S_ISREG(direntry->d_inode->i_mode)) {
 			if (direntry->d_inode->i_mapping)
 				filemap_fdatawait(direntry->d_inode->i_mapping);
 			/* may eventually have to do this for open files too */
 			if (list_empty(&(cifsInode->openFileList))) {
-			/* Has changed on server - flush read ahead pages */
+				/* changed on server - flush read ahead pages */
 				cFYI(1, ("Invalidating read ahead data on "
 					 "closed file"));
 				invalidate_remote_inode(direntry->d_inode);
 			}
 		}
+	}
 /*	up(&direntry->d_inode->i_sem); */
 	
 	kfree(full_path);