Commit 1dd53957 authored by Vivek Goyal's avatar Vivek Goyal Committed by Miklos Szeredi
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virtiofs: add a mount option to enable dax 



Add a mount option to allow using dax with virtio_fs.

Signed-off-by: default avatarVivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 22f3787e

fs/fuse/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -38,3 +38,16 @@ config VIRTIO_FS 


	  If you want to share files between guests or with the host, answer Y

	  or M.



config FUSE_DAX

	bool "Virtio Filesystem Direct Host Memory Access support"

	default y

	depends on VIRTIO_FS

	depends on FS_DAX

	depends on DAX_DRIVER

	help

	  This allows bypassing guest page cache and allows mapping host page

	  cache directly in guest address space.



	  If you want to allow mounting a Virtio Filesystem with the "dax"

	  option, answer Y.

fs/fuse/Makefile

+4 −2
Original line number Diff line number Diff line
@@ -7,5 +7,7 @@ obj-$(CONFIG_FUSE_FS) += fuse.o 
obj-$(CONFIG_CUSE) += cuse.o

obj-$(CONFIG_VIRTIO_FS) += virtiofs.o



fuse-objs := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o

virtiofs-y += virtio_fs.o
 
fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o

fuse-$(CONFIG_FUSE_DAX) += dax.o



virtiofs-y := virtio_fs.o

fs/fuse/dax.c

0 → 100644
+36 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * dax: direct host memory access

 * Copyright (C) 2020 Red Hat, Inc.

 */



#include "fuse_i.h"



#include <linux/dax.h>



struct fuse_conn_dax {

	/* DAX device */

	struct dax_device *dev;

};



void fuse_dax_conn_free(struct fuse_conn *fc)

{

	kfree(fc->dax);

}



int fuse_dax_conn_alloc(struct fuse_conn *fc, struct dax_device *dax_dev)

{

	struct fuse_conn_dax *fcd;



	if (!dax_dev)

		return 0;



	fcd = kzalloc(sizeof(*fcd), GFP_KERNEL);

	if (!fcd)

		return -ENOMEM;



	fcd->dev = dax_dev;



	fc->dax = fcd;

	return 0;

}

fs/fuse/fuse_i.h

+14 −0
Original line number Diff line number Diff line
@@ -483,10 +483,14 @@ struct fuse_fs_context { 
	bool no_control:1;

	bool no_force_umount:1;

	bool legacy_opts_show:1;

	bool dax:1;

	unsigned int max_read;

	unsigned int blksize;

	const char *subtype;



	/* DAX device, may be NULL */

	struct dax_device *dax_dev;



	/* fuse_dev pointer to fill in, should contain NULL on entry */

	void **fudptr;

};
@@ -755,6 +759,11 @@ struct fuse_conn { 


	/** List of device instances belonging to this connection */

	struct list_head devices;



#ifdef CONFIG_FUSE_DAX

	/* Dax specific conn data, non-NULL if DAX is enabled */

	struct fuse_conn_dax *dax;

#endif

};



static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
@@ -1093,4 +1102,9 @@ unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args); 
u64 fuse_get_unique(struct fuse_iqueue *fiq);

void fuse_free_conn(struct fuse_conn *fc);



/* dax.c */



int fuse_dax_conn_alloc(struct fuse_conn *fc, struct dax_device *dax_dev);

void fuse_dax_conn_free(struct fuse_conn *fc);



#endif /* _FS_FUSE_I_H */

fs/fuse/inode.c

+17 −1
Original line number Diff line number Diff line
@@ -587,6 +587,11 @@ static int fuse_show_options(struct seq_file *m, struct dentry *root) 
		if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)

			seq_printf(m, ",blksize=%lu", sb->s_blocksize);

	}

#ifdef CONFIG_FUSE_DAX

	if (fc->dax)

		seq_puts(m, ",dax");

#endif



	return 0;

}
@@ -651,6 +656,8 @@ void fuse_conn_put(struct fuse_conn *fc) 
	if (refcount_dec_and_test(&fc->count)) {

		struct fuse_iqueue *fiq = &fc->iq;



		if (IS_ENABLED(CONFIG_FUSE_DAX))

			fuse_dax_conn_free(fc);

		if (fiq->ops->release)

			fiq->ops->release(fiq);

		put_pid_ns(fc->pid_ns);
@@ -1175,11 +1182,17 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 
	if (sb->s_user_ns != &init_user_ns)

		sb->s_xattr = fuse_no_acl_xattr_handlers;



	if (IS_ENABLED(CONFIG_FUSE_DAX)) {

		err = fuse_dax_conn_alloc(fc, ctx->dax_dev);

		if (err)

			goto err;

	}



	if (ctx->fudptr) {

		err = -ENOMEM;

		fud = fuse_dev_alloc_install(fc);

		if (!fud)

			goto err;

			goto err_free_dax;

	}



	fc->dev = sb->s_dev;
@@ -1234,6 +1247,9 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 
 err_dev_free:

	if (fud)

		fuse_dev_free(fud);

 err_free_dax:

	if (IS_ENABLED(CONFIG_FUSE_DAX))

		fuse_dax_conn_free(fc);

 err:

	return err;

}