[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 b7d3a05c062c..fc66861b3598 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;