Commit 0ce7c12e authored by Ivan Babrou's avatar Ivan Babrou Committed by Greg Kroah-Hartman
Browse files

kernfs: attach uuid for every kernfs and report it in fsid 



The following two commits added the same thing for tmpfs:

* commit 2b4db796 ("tmpfs: generate random sb->s_uuid")
* commit 59cda49e ("shmem: allow reporting fanotify events with file handles on tmpfs")

Having fsid allows using fanotify, which is especially handy for cgroups,
where one might be interested in knowing when they are created or removed.

Signed-off-by: default avatarIvan Babrou <ivan@cloudflare.com>
Acked-by: default avatarJan Kara <jack@suse.cz>
Acked-by: default avatarChristian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230731184731.64568-1-ivan@cloudflare.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 79038a99

fs/kernfs/mount.c

+12 −1
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ 
#include <linux/namei.h>

#include <linux/seq_file.h>

#include <linux/exportfs.h>

#include <linux/uuid.h>

#include <linux/statfs.h>



#include "kernfs-internal.h"
@@ -45,8 +47,15 @@ static int kernfs_sop_show_path(struct seq_file *sf, struct dentry *dentry) 
	return 0;

}



static int kernfs_statfs(struct dentry *dentry, struct kstatfs *buf)

{

	simple_statfs(dentry, buf);

	buf->f_fsid = uuid_to_fsid(dentry->d_sb->s_uuid.b);

	return 0;

}



const struct super_operations kernfs_sops = {

	.statfs		= simple_statfs,

	.statfs		= kernfs_statfs,

	.drop_inode	= generic_delete_inode,

	.evict_inode	= kernfs_evict_inode,
@@ -351,6 +360,8 @@ int kernfs_get_tree(struct fs_context *fc) 
		}

		sb->s_flags |= SB_ACTIVE;



		uuid_gen(&sb->s_uuid);



		down_write(&root->kernfs_supers_rwsem);

		list_add(&info->node, &info->root->supers);

		up_write(&root->kernfs_supers_rwsem);