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Commit c7f404b4 authored by Al Viro's avatar Al Viro
Browse files

vfs: new superblock methods to override /proc/*/mount{s,info} 



a) ->show_devname(m, mnt) - what to put into devname columns in mounts,
mountinfo and mountstats
b) ->show_path(m, mnt) - what to put into relative path column in mountinfo

Leaving those NULL gives old behaviour.  NFS switched to using those.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent f8ad9c4b

fs/namespace.c

+30 −9
Original line number Diff line number Diff line
@@ -978,7 +978,13 @@ static int show_vfsmnt(struct seq_file *m, void *v) 
	int err = 0;

	struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };



	if (mnt->mnt_sb->s_op->show_devname) {

		err = mnt->mnt_sb->s_op->show_devname(m, mnt);

		if (err)

			goto out;

	} else {

		mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");

	}

	seq_putc(m, ' ');

	seq_path(m, &mnt_path, " \t\n\\");

	seq_putc(m, ' ');
@@ -1025,7 +1031,12 @@ static int show_mountinfo(struct seq_file *m, void *v) 


	seq_printf(m, "%i %i %u:%u ", mnt->mnt_id, mnt->mnt_parent->mnt_id,

		   MAJOR(sb->s_dev), MINOR(sb->s_dev));

	if (sb->s_op->show_path)

		err = sb->s_op->show_path(m, mnt);

	else

		seq_dentry(m, mnt->mnt_root, " \t\n\\");

	if (err)

		goto out;

	seq_putc(m, ' ');

	seq_path_root(m, &mnt_path, &root, " \t\n\\");

	if (root.mnt != p->root.mnt || root.dentry != p->root.dentry) {
@@ -1060,7 +1071,12 @@ static int show_mountinfo(struct seq_file *m, void *v) 
	seq_puts(m, " - ");

	show_type(m, sb);

	seq_putc(m, ' ');

	if (sb->s_op->show_devname)

		err = sb->s_op->show_devname(m, mnt);

	else

		mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");

	if (err)

		goto out;

	seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");

	err = show_sb_opts(m, sb);

	if (err)
@@ -1086,11 +1102,15 @@ static int show_vfsstat(struct seq_file *m, void *v) 
	int err = 0;



	/* device */

	if (mnt->mnt_sb->s_op->show_devname) {

		err = mnt->mnt_sb->s_op->show_devname(m, mnt);

	} else {

		if (mnt->mnt_devname) {

			seq_puts(m, "device ");

			mangle(m, mnt->mnt_devname);

		} else

			seq_puts(m, "no device");

	}



	/* mount point */

	seq_puts(m, " mounted on ");
@@ -1104,6 +1124,7 @@ static int show_vfsstat(struct seq_file *m, void *v) 
	/* optional statistics */

	if (mnt->mnt_sb->s_op->show_stats) {

		seq_putc(m, ' ');

		if (!err)

			err = mnt->mnt_sb->s_op->show_stats(m, mnt);

	}

fs/nfs/super.c

+28 −0
Original line number Diff line number Diff line
@@ -263,6 +263,8 @@ static match_table_t nfs_local_lock_tokens = { 
static void nfs_umount_begin(struct super_block *);

static int  nfs_statfs(struct dentry *, struct kstatfs *);

static int  nfs_show_options(struct seq_file *, struct vfsmount *);

static int  nfs_show_devname(struct seq_file *, struct vfsmount *);

static int  nfs_show_path(struct seq_file *, struct vfsmount *);

static int  nfs_show_stats(struct seq_file *, struct vfsmount *);

static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);

static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
@@ -296,6 +298,8 @@ static const struct super_operations nfs_sops = { 
	.evict_inode	= nfs_evict_inode,

	.umount_begin	= nfs_umount_begin,

	.show_options	= nfs_show_options,

	.show_devname	= nfs_show_devname,

	.show_path	= nfs_show_path,

	.show_stats	= nfs_show_stats,

	.remount_fs	= nfs_remount,

};
@@ -366,6 +370,8 @@ static const struct super_operations nfs4_sops = { 
	.evict_inode	= nfs4_evict_inode,

	.umount_begin	= nfs_umount_begin,

	.show_options	= nfs_show_options,

	.show_devname	= nfs_show_devname,

	.show_path	= nfs_show_path,

	.show_stats	= nfs_show_stats,

	.remount_fs	= nfs_remount,

};
@@ -726,6 +732,28 @@ static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt) 
	return 0;

}



static int nfs_show_devname(struct seq_file *m, struct vfsmount *mnt)

{

	char *page = (char *) __get_free_page(GFP_KERNEL);

	char *devname, *dummy;

	int err = 0;

	if (!page)

		return -ENOMEM;

	devname = nfs_path(&dummy, mnt->mnt_root, page, PAGE_SIZE);

	if (IS_ERR(devname))

		err = PTR_ERR(devname);

	else

		seq_escape(m, devname, " \t\n\\");

	free_page((unsigned long)page);

	return err;

}



static int nfs_show_path(struct seq_file *m, struct vfsmount *mnt)

{

	seq_puts(m, "/");

	return 0;

}



/*

 * Present statistical information for this VFS mountpoint

 */

include/linux/fs.h

+2 −0
Original line number Diff line number Diff line
@@ -1632,6 +1632,8 @@ struct super_operations { 
	void (*umount_begin) (struct super_block *);



	int (*show_options)(struct seq_file *, struct vfsmount *);

	int (*show_devname)(struct seq_file *, struct vfsmount *);

	int (*show_path)(struct seq_file *, struct vfsmount *);

	int (*show_stats)(struct seq_file *, struct vfsmount *);

#ifdef CONFIG_QUOTA

	ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);