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Commit 759832b6 authored by Nikhilesh Reddy's avatar Nikhilesh Reddy Committed by Sahitya Tummala
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fuse: Add support for shortcircuited read/write for files 



Add support for shortcircuited read/write for files
when enabled through a userspace init option of
FUSE_PASSTHROUGH.

When FUSE_PASSTHROUGH is enabled all the reads and writes
to the fuse mount point go directly to the native filesystem
rather than through the fuse daemon. All requsts that aren't
read/write still go thought the userspace code.

This allows for significantly better performance on read and writes
and the difference between fuse and the native lower filesystem is
negligible.

Change-Id: If3bab9f776670426cb7801fba8151505a5b94a3c
Signed-off-by: default avatarNikhilesh Reddy <reddyn@codeaurora.org>
Signed-off-by: default avatarSahitya Tummala <stummala@codeaurora.org>
parent 814e5c69

fs/fuse/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -5,4 +5,4 @@ 
obj-$(CONFIG_FUSE_FS) += fuse.o

obj-$(CONFIG_CUSE) += cuse.o



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

fs/fuse/dev.c

+12 −3
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
*/



#include "fuse_i.h"

#include "fuse_passthrough.h"



#include <linux/init.h>

#include <linux/module.h>
@@ -550,10 +551,15 @@ ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args) 
	       args->out.numargs * sizeof(struct fuse_arg));

	fuse_request_send(fc, req);

	ret = req->out.h.error;

	if (!ret && args->out.argvar) {

		BUG_ON(args->out.numargs != 1);

	if (!ret) {

		if (args->out.argvar) {

			WARN_ON(args->out.numargs != 1);

			ret = req->out.args[0].size;

		}



		if (req->passthrough_filp != NULL)

			args->out.passthrough_filp = req->passthrough_filp;

	}

	fuse_put_request(fc, req);



	return ret;
@@ -1890,6 +1896,9 @@ static ssize_t fuse_dev_do_write(struct fuse_dev *fud, 
	}

	fuse_copy_finish(cs);



	fuse_setup_passthrough(fc, req);





	spin_lock(&fpq->lock);

	clear_bit(FR_LOCKED, &req->flags);

	if (!fpq->connected)

fs/fuse/dir.c

+3 −0
Original line number Diff line number Diff line
@@ -491,6 +491,7 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry, 
	args.out.args[0].value = &outentry;

	args.out.args[1].size = sizeof(outopen);

	args.out.args[1].value = &outopen;

	args.out.passthrough_filp = NULL;

	err = fuse_simple_request(fc, &args);

	if (err)

		goto out_free_ff;
@@ -502,6 +503,8 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry, 
	ff->fh = outopen.fh;

	ff->nodeid = outentry.nodeid;

	ff->open_flags = outopen.open_flags;

	if (args.out.passthrough_filp != NULL)

		ff->passthrough_filp = args.out.passthrough_filp;

	inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,

			  &outentry.attr, entry_attr_timeout(&outentry), 0);

	if (!inode) {

fs/fuse/file.c

+42 −5
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
*/



#include "fuse_i.h"

#include "fuse_passthrough.h"



#include <linux/pagemap.h>

#include <linux/slab.h>
@@ -21,8 +22,10 @@ 
static const struct file_operations fuse_direct_io_file_operations;



static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,

			  int opcode, struct fuse_open_out *outargp)

			  int opcode, struct fuse_open_out *outargp,

			  struct file **passthrough_filpp)

{

	int ret_val;

	struct fuse_open_in inarg;

	FUSE_ARGS(args);
@@ -38,8 +41,14 @@ static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file, 
	args.out.numargs = 1;

	args.out.args[0].size = sizeof(*outargp);

	args.out.args[0].value = outargp;

	args.out.passthrough_filp = NULL;



	return fuse_simple_request(fc, &args);

	ret_val = fuse_simple_request(fc, &args);



	if (args.out.passthrough_filp != NULL)

		*passthrough_filpp = args.out.passthrough_filp;



	return ret_val;

}



struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
@@ -50,6 +59,11 @@ struct fuse_file *fuse_file_alloc(struct fuse_conn *fc) 
	if (unlikely(!ff))

		return NULL;



	ff->passthrough_filp = NULL;

	ff->passthrough_enabled = 0;

	if (fc->passthrough)

		ff->passthrough_enabled = 1;



	ff->fc = fc;

	ff->reserved_req = fuse_request_alloc(0);

	if (unlikely(!ff->reserved_req)) {
@@ -118,6 +132,7 @@ int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, 
		 bool isdir)

{

	struct fuse_file *ff;

	struct file *passthrough_filp = NULL;

	int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;



	ff = fuse_file_alloc(fc);
@@ -130,11 +145,12 @@ int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, 
		struct fuse_open_out outarg;

		int err;



		err = fuse_send_open(fc, nodeid, file, opcode, &outarg);

		err = fuse_send_open(fc, nodeid, file, opcode, &outarg,

				     &(passthrough_filp));

		if (!err) {

			ff->fh = outarg.fh;

			ff->open_flags = outarg.open_flags;



			ff->passthrough_filp = passthrough_filp;

		} else if (err != -ENOSYS || isdir) {

			fuse_file_free(ff);

			return err;
@@ -253,6 +269,8 @@ void fuse_release_common(struct file *file, int opcode) 
	if (unlikely(!ff))

		return;



	fuse_passthrough_release(ff);



	req = ff->reserved_req;

	fuse_prepare_release(ff, file->f_flags, opcode);
@@ -917,8 +935,10 @@ static int fuse_readpages(struct file *file, struct address_space *mapping, 


static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)

{

	ssize_t ret_val;

	struct inode *inode = iocb->ki_filp->f_mapping->host;

	struct fuse_conn *fc = get_fuse_conn(inode);

	struct fuse_file *ff = iocb->ki_filp->private_data;



	/*

	 * In auto invalidate mode, always update attributes on read.
@@ -933,7 +953,12 @@ static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 
			return err;

	}



	return generic_file_read_iter(iocb, to);

	if (ff && ff->passthrough_enabled && ff->passthrough_filp)

		ret_val = fuse_passthrough_read_iter(iocb, to);

	else

		ret_val = generic_file_read_iter(iocb, to);



	return ret_val;

}



static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
@@ -1165,6 +1190,7 @@ static ssize_t fuse_perform_write(struct file *file, 
static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)

{

	struct file *file = iocb->ki_filp;

	struct fuse_file *ff = file->private_data;

	struct address_space *mapping = file->f_mapping;

	ssize_t written = 0;

	ssize_t written_buffered = 0;
@@ -1198,6 +1224,11 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 
	if (err)

		goto out;



	if (ff && ff->passthrough_enabled && ff->passthrough_filp) {

		written = fuse_passthrough_write_iter(iocb, from);

		goto out;

	}



	if (iocb->ki_flags & IOCB_DIRECT) {

		loff_t pos = iocb->ki_pos;

		written = generic_file_direct_write(iocb, from);
@@ -2069,6 +2100,9 @@ static const struct vm_operations_struct fuse_file_vm_ops = { 


static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)

{

	struct fuse_file *ff = file->private_data;



	ff->passthrough_enabled = 0;

	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))

		fuse_link_write_file(file);
@@ -2079,6 +2113,9 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma) 


static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)

{

	struct fuse_file *ff = file->private_data;



	ff->passthrough_enabled = 0;

	/* Can't provide the coherency needed for MAP_SHARED */

	if (vma->vm_flags & VM_MAYSHARE)

		return -ENODEV;

fs/fuse/fuse_i.h

+11 −0
Original line number Diff line number Diff line
@@ -153,6 +153,10 @@ struct fuse_file { 


	/** Has flock been performed on this file? */

	bool flock:1;



	/* the read write file */

	struct file *passthrough_filp;

	bool passthrough_enabled;

};



/** One input argument of a request */
@@ -232,6 +236,7 @@ struct fuse_args { 
		unsigned argvar:1;

		unsigned numargs;

		struct fuse_arg args[2];

		struct file *passthrough_filp;

	} out;

};
@@ -382,6 +387,9 @@ struct fuse_req { 


	/** Request is stolen from fuse_file->reserved_req */

	struct file *stolen_file;



	/** fuse passthrough file  */

	struct file *passthrough_filp;

};



struct fuse_iqueue {
@@ -542,6 +550,9 @@ struct fuse_conn { 
	/** handle fs handles killing suid/sgid/cap on write/chown/trunc */

	unsigned handle_killpriv:1;



	/** passthrough IO. */

	unsigned passthrough:1;



	/*

	 * The following bitfields are only for optimization purposes

	 * and hence races in setting them will not cause malfunction