libmount: optimize mtab and utab parsing in umount

create 8000 NFS mountpoints:
	#!/bin/bash
	mount=/tmp/mount
	if [ ! -d $mount ]; then
	    mkdir -p $mount
	fi
	for dir in {1..8000}; do
	    if [ ! -d $mount/$dir ]; then
		mkdir -p $mount/$dir
	    fi
	    echo mount $dir
	    mount -t nfs 127.0.0.1:/ $mount/$dir
	done

old version:
	time ./umount /tmp/mount/2255

	real	0m1.254s
	user	0m1.002s
	sys	0m0.238s

new version:
	time ./umount /tmp/mount/2244

	real	0m0.332s
	user	0m0.111s
	sys	0m0.218s

Reported-by: chenditang <chendt.fnst@cn.fujitsu.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/libmount/src/mountP.h b/libmount/src/mountP.h
index 0ef073a69..bbaa2c6c4 100644
--- a/libmount/src/mountP.h
+++ b/libmount/src/mountP.h
@@ -148,6 +148,10 @@ extern int mnt_get_filesystems(char ***filesystems, const char *pattern);
 extern void mnt_free_filesystems(char **filesystems);
 
 /* tab.c */
+extern int mnt_table_set_parser_fltrcb(	struct libmnt_table *tb,
+					int (*cb)(struct libmnt_fs *, void *),
+					void *data);
+
 extern struct libmnt_fs *mnt_table_get_fs_root(struct libmnt_table *tb,
                                         struct libmnt_fs *fs,
                                         unsigned long mountflags,
@@ -248,6 +252,10 @@ struct libmnt_table {
         int		(*errcb)(struct libmnt_table *tb,
 				 const char *filename, int line);
 
+	int		(*fltrcb)(struct libmnt_fs *fs, void *data);
+	void		*fltrcb_data;
+
+
 	struct list_head	ents;	/* list of entries (libmnt_fs) */
 };
 
@@ -285,6 +293,9 @@ struct libmnt_context
 	int	(*table_errcb)(struct libmnt_table *tb,	/* callback for libmnt_table structs */
 			 const char *filename, int line);
 
+	int	(*table_fltrcb)(struct libmnt_fs *fs, void *data);	/* callback for libmnt_table structs */
+	void	*table_fltrcb_data;
+
 	char	*(*pwd_get_cb)(struct libmnt_context *);		/* get encryption password */
 	void	(*pwd_release_cb)(struct libmnt_context *, char *);	/* release password */
 
@@ -395,6 +406,10 @@ extern int mnt_context_clear_loopdev(struct libmnt_context *cxt);
 
 extern int mnt_fork_context(struct libmnt_context *cxt);
 
+extern int mnt_context_set_tabfilter(struct libmnt_context *cxt,
+			int (*fltr)(struct libmnt_fs *, void *),
+			void *data);
+
 /* tab_update.c */
 extern int mnt_update_set_filename(struct libmnt_update *upd,
 				   const char *filename, int userspace_only);