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Commit 1d278a87 authored by David Howells's avatar David Howells Committed by Al Viro
Browse files

VFS: Kill off s_options and helpers 



Kill off s_options, save/replace_mount_options() and generic_show_options()
as all filesystems now implement ->show_options() for themselves.  This
should make it easier to implement a context-based mount where the mount
options can be passed individually over a file descriptor.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 4dfdb713

Documentation/filesystems/vfs.txt

+0 −6
Original line number Diff line number Diff line
@@ -1187,12 +1187,6 @@ The underlying reason for the above rules is to make sure, that a 
mount can be accurately replicated (e.g. umounting and mounting again)

based on the information found in /proc/mounts.



A simple method of saving options at mount/remount time and showing

them is provided with the save_mount_options() and

generic_show_options() helper functions.  Please note, that using

these may have drawbacks.  For more info see header comments for these

functions in fs/namespace.c.



Resources

=========

fs/efivarfs/super.c

+0 −1
Original line number Diff line number Diff line
@@ -29,7 +29,6 @@ static const struct super_operations efivarfs_ops = { 
	.statfs = simple_statfs,

	.drop_inode = generic_delete_inode,

	.evict_inode = efivarfs_evict_inode,

	.show_options = generic_show_options,

};



static struct super_block *efivarfs_sb;

fs/namespace.c

+0 −59
Original line number Diff line number Diff line
@@ -1237,65 +1237,6 @@ struct vfsmount *mnt_clone_internal(const struct path *path) 
	return &p->mnt;

}



static inline void mangle(struct seq_file *m, const char *s)

{

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

}



/*

 * Simple .show_options callback for filesystems which don't want to

 * implement more complex mount option showing.

 *

 * See also save_mount_options().

 */

int generic_show_options(struct seq_file *m, struct dentry *root)

{

	const char *options;



	rcu_read_lock();

	options = rcu_dereference(root->d_sb->s_options);



	if (options != NULL && options[0]) {

		seq_putc(m, ',');

		mangle(m, options);

	}

	rcu_read_unlock();



	return 0;

}

EXPORT_SYMBOL(generic_show_options);



/*

 * If filesystem uses generic_show_options(), this function should be

 * called from the fill_super() callback.

 *

 * The .remount_fs callback usually needs to be handled in a special

 * way, to make sure, that previous options are not overwritten if the

 * remount fails.

 *

 * Also note, that if the filesystem's .remount_fs function doesn't

 * reset all options to their default value, but changes only newly

 * given options, then the displayed options will not reflect reality

 * any more.

 */

void save_mount_options(struct super_block *sb, char *options)

{

	BUG_ON(sb->s_options);

	rcu_assign_pointer(sb->s_options, kstrdup(options, GFP_KERNEL));

}

EXPORT_SYMBOL(save_mount_options);



void replace_mount_options(struct super_block *sb, char *options)

{

	char *old = sb->s_options;

	rcu_assign_pointer(sb->s_options, options);

	if (old) {

		synchronize_rcu();

		kfree(old);

	}

}

EXPORT_SYMBOL(replace_mount_options);



#ifdef CONFIG_PROC_FS

/* iterator; we want it to have access to namespace_sem, thus here... */

static void *m_start(struct seq_file *m, loff_t *pos)

fs/super.c

+0 −1
Original line number Diff line number Diff line
@@ -168,7 +168,6 @@ static void destroy_super(struct super_block *s) 
	WARN_ON(!list_empty(&s->s_mounts));

	put_user_ns(s->s_user_ns);

	kfree(s->s_subtype);

	kfree(s->s_options);

	call_rcu(&s->rcu, destroy_super_rcu);

}

include/linux/fs.h

+0 −9
Original line number Diff line number Diff line
@@ -1351,11 +1351,6 @@ struct super_block { 
	 */

	char *s_subtype;



	/*

	 * Saved mount options for lazy filesystems using

	 * generic_show_options()

	 */

	char __rcu *s_options;

	const struct dentry_operations *s_d_op; /* default d_op for dentries */



	/*
@@ -3033,10 +3028,6 @@ extern void setattr_copy(struct inode *inode, const struct iattr *attr); 


extern int file_update_time(struct file *file);



extern int generic_show_options(struct seq_file *m, struct dentry *root);

extern void save_mount_options(struct super_block *sb, char *options);

extern void replace_mount_options(struct super_block *sb, char *options);



static inline bool io_is_direct(struct file *filp)

{

	return (filp->f_flags & O_DIRECT) || IS_DAX(filp->f_mapping->host);