[readdir] introduce ->iterate(), ctx->pos, dir_emit()

New method - ->iterate(file, ctx).  That's the replacement for ->readdir();
it takes callback from ctx->actor, uses ctx->pos instead of file->f_pos and
calls dir_emit(ctx, ...) instead of filldir(data, ...).  It does *not*
update file->f_pos (or look at it, for that matter); iterate_dir() does the
update.

Note that dir_emit() takes the offset from ctx->pos (and eventually
filldir_t will lose that argument).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 15 insertions, 4 deletions

diff --git a/fs/coda/dir.c b/fs/coda/dir.c
index b7d3a05..fc66861 100644
--- a/fs/coda/dir.c
+++ b/fs/coda/dir.c
@@ -391,8 +391,7 @@ static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
 	if (!host_file->f_op)
 		return -ENOTDIR;
 
-	if (host_file->f_op->readdir)
-	{
+	if (host_file->f_op->readdir) {
 		/* potemkin case: we were handed a directory inode.
 		 * We can't use vfs_readdir because we have to keep the file
 		 * position in sync between the coda_file and the host_file.
@@ -410,8 +409,20 @@ static int coda_readdir(struct file *coda_file, void *buf, filldir_t filldir)
 
 		coda_file->f_pos = host_file->f_pos;
 		mutex_unlock(&host_inode->i_mutex);
-	}
-	else /* Venus: we must read Venus dirents from a file */
+	} else if (host_file->f_op->iterate) {
+		struct inode *host_inode = file_inode(host_file);
+		struct dir_context *ctx = buf;
+
+		mutex_lock(&host_inode->i_mutex);
+		ret = -ENOENT;
+		if (!IS_DEADDIR(host_inode)) {
+			ret = host_file->f_op->iterate(host_file, ctx);
+			file_accessed(host_file);
+		}
+		mutex_unlock(&host_inode->i_mutex);
+
+		coda_file->f_pos = ctx->pos;
+	} else /* Venus: we must read Venus dirents from a file */
 		ret = coda_venus_readdir(coda_file, buf, filldir);
 
 	return ret;