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Commit 31d6d5ce authored by David Howells's avatar David Howells Committed by Al Viro
Browse files

vfs: Provide a mount_pseudo-replacement for the new mount API 



Provide a function, init_pseudo(), that provides a common
infrastructure for converting pseudo-filesystems that can never be
mountable.

[AV: once all users of mount_pseudo_xattr() get converted, it will be folded
into pseudo_fs_get_tree()]

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
cc: linux-fsdevel@vger.kernel.org
parent c80fa7c8

fs/libfs.c

+46 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ 
#include <linux/exportfs.h>

#include <linux/writeback.h>

#include <linux/buffer_head.h> /* sync_mapping_buffers */

#include <linux/fs_context.h>

#include <linux/pseudo_fs.h>



#include <linux/uaccess.h>
@@ -235,6 +237,50 @@ static const struct super_operations simple_super_operations = { 
	.statfs		= simple_statfs,

};



static int pseudo_fs_get_tree(struct fs_context *fc)

{

	struct pseudo_fs_context *ctx = fc->fs_private;

	struct dentry *root;



	root = mount_pseudo_xattr(fc->fs_type,

				  ctx->ops, ctx->xattr,

			          ctx->dops, ctx->magic);

	if (IS_ERR(root))

		return PTR_ERR(root);



	fc->root = root;

	return 0;

}



static void pseudo_fs_free(struct fs_context *fc)

{

	kfree(fc->fs_private);

}



static const struct fs_context_operations pseudo_fs_context_ops = {

	.free		= pseudo_fs_free,

	.get_tree	= pseudo_fs_get_tree,

};



/*

 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that

 * will never be mountable)

 */

struct pseudo_fs_context *init_pseudo(struct fs_context *fc,

					unsigned long magic)

{

	struct pseudo_fs_context *ctx;



	ctx = kzalloc(sizeof(struct pseudo_fs_context), GFP_KERNEL);

	if (likely(ctx)) {

		ctx->magic = magic;

		fc->fs_private = ctx;

		fc->ops = &pseudo_fs_context_ops;

	}

	return ctx;

}

EXPORT_SYMBOL(init_pseudo);



/*

 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that

 * will never be mountable)

include/linux/pseudo_fs.h

0 → 100644
+16 −0
Original line number Diff line number Diff line 
#ifndef __LINUX_PSEUDO_FS__

#define __LINUX_PSEUDO_FS__



#include <linux/fs_context.h>



struct pseudo_fs_context {

	const struct super_operations *ops;

	const struct xattr_handler **xattr;

	const struct dentry_operations *dops;

	unsigned long magic;

};



struct pseudo_fs_context *init_pseudo(struct fs_context *fc,

				      unsigned long magic);



#endif