Change calling conventions for filldir_t

filldir_t instances (directory iterators callbacks) used to return 0 for
"OK, keep going" or -E... for "stop".  Note that it's *NOT* how the
error values are reported - the rules for those are callback-dependent
and ->iterate{,_shared}() instances only care about zero vs. non-zero
(look at emit_dir() and friends).

So let's just return bool ("should we keep going?") - it's less confusing
that way.  The choice between "true means keep going" and "true means
stop" is bikesheddable; we have two groups of callbacks -
	do something for everything in directory, until we run into problem
and
	find an entry in directory and do something to it.

The former tended to use 0/-E... conventions - -E<something> on failure.
The latter tended to use 0/1, 1 being "stop, we are done".
The callers treated anything non-zero as "stop", ignoring which
non-zero value did they get.

"true means stop" would be more natural for the second group; "true
means keep going" - for the first one.  I tried both variants and
the things like
	if allocation failed
		something = -ENOMEM;
		return true;
just looked unnatural and asking for trouble.

[folded suggestion from Matthew Wilcox <willy@infradead.org>]
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 14 insertions, 14 deletions

diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 78f62cc1797b..8c25d185cdc0 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -170,7 +170,7 @@ static struct ovl_cache_entry *ovl_cache_entry_new(struct ovl_readdir_data *rdd,
 	return p;
 }
 
-static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
+static bool ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
 				  const char *name, int len, u64 ino,
 				  unsigned int d_type)
 {
@@ -179,22 +179,22 @@ static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
 	struct ovl_cache_entry *p;
 
 	if (ovl_cache_entry_find_link(name, len, &newp, &parent))
-		return 0;
+		return true;
 
 	p = ovl_cache_entry_new(rdd, name, len, ino, d_type);
 	if (p == NULL) {
 		rdd->err = -ENOMEM;
-		return -ENOMEM;
+		return false;
 	}
 
 	list_add_tail(&p->l_node, rdd->list);
 	rb_link_node(&p->node, parent, newp);
 	rb_insert_color(&p->node, rdd->root);
 
-	return 0;
+	return true;
 }
 
-static int ovl_fill_lowest(struct ovl_readdir_data *rdd,
+static bool ovl_fill_lowest(struct ovl_readdir_data *rdd,
 			   const char *name, int namelen,
 			   loff_t offset, u64 ino, unsigned int d_type)
 {
@@ -211,7 +211,7 @@ static int ovl_fill_lowest(struct ovl_readdir_data *rdd,
 			list_add_tail(&p->l_node, &rdd->middle);
 	}
 
-	return rdd->err;
+	return rdd->err == 0;
 }
 
 void ovl_cache_free(struct list_head *list)
@@ -250,7 +250,7 @@ static void ovl_cache_put(struct ovl_dir_file *od, struct dentry *dentry)
 	}
 }
 
-static int ovl_fill_merge(struct dir_context *ctx, const char *name,
+static bool ovl_fill_merge(struct dir_context *ctx, const char *name,
 			  int namelen, loff_t offset, u64 ino,
 			  unsigned int d_type)
 {
@@ -528,7 +528,7 @@ fail:
 	goto out;
 }
 
-static int ovl_fill_plain(struct dir_context *ctx, const char *name,
+static bool ovl_fill_plain(struct dir_context *ctx, const char *name,
 			  int namelen, loff_t offset, u64 ino,
 			  unsigned int d_type)
 {
@@ -540,11 +540,11 @@ static int ovl_fill_plain(struct dir_context *ctx, const char *name,
 	p = ovl_cache_entry_new(rdd, name, namelen, ino, d_type);
 	if (p == NULL) {
 		rdd->err = -ENOMEM;
-		return -ENOMEM;
+		return false;
 	}
 	list_add_tail(&p->l_node, rdd->list);
 
-	return 0;
+	return true;
 }
 
 static int ovl_dir_read_impure(struct path *path,  struct list_head *list,
@@ -648,7 +648,7 @@ struct ovl_readdir_translate {
 	bool xinowarn;
 };
 
-static int ovl_fill_real(struct dir_context *ctx, const char *name,
+static bool ovl_fill_real(struct dir_context *ctx, const char *name,
 			   int namelen, loff_t offset, u64 ino,
 			   unsigned int d_type)
 {
@@ -1027,7 +1027,7 @@ void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
 	inode_unlock(upper->d_inode);
 }
 
-static int ovl_check_d_type(struct dir_context *ctx, const char *name,
+static bool ovl_check_d_type(struct dir_context *ctx, const char *name,
 			  int namelen, loff_t offset, u64 ino,
 			  unsigned int d_type)
 {
@@ -1036,12 +1036,12 @@ static int ovl_check_d_type(struct dir_context *ctx, const char *name,
 
 	/* Even if d_type is not supported, DT_DIR is returned for . and .. */
 	if (!strncmp(name, ".", namelen) || !strncmp(name, "..", namelen))
-		return 0;
+		return true;
 
 	if (d_type != DT_UNKNOWN)
 		rdd->d_type_supported = true;
 
-	return 0;
+	return true;
 }
 
 /*