Commit 0b05b183 authored by Anand V. Avati's avatar Anand V. Avati Committed by Miklos Szeredi
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fuse: implement NFS-like readdirplus support 



This patch implements readdirplus support in FUSE, similar to NFS.
The payload returned in the readdirplus call contains
'fuse_entry_out' structure thereby providing all the necessary inputs
for 'faking' a lookup() operation on the spot.

If the dentry and inode already existed (for e.g. in a re-run of ls -l)
then just the inode attributes timeout and dentry timeout are refreshed.

With a simple client->network->server implementation of a FUSE based
filesystem, the following performance observations were made:

Test: Performing a filesystem crawl over 20,000 files with

sh# time ls -lR /mnt

Without readdirplus:
Run 1: 18.1s
Run 2: 16.0s
Run 3: 16.2s

With readdirplus:
Run 1: 4.1s
Run 2: 3.8s
Run 3: 3.8s

The performance improvement is significant as it avoided 20,000 upcalls
calls (lookup). Cache consistency is no worse than what already is.

Signed-off-by: default avatarAnand V. Avati <avati@redhat.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent ff7532ca

fs/fuse/dev.c

+19 −0
Original line number Diff line number Diff line
@@ -491,6 +491,25 @@ void fuse_request_send_background_locked(struct fuse_conn *fc, 
	fuse_request_send_nowait_locked(fc, req);

}



void fuse_force_forget(struct file *file, u64 nodeid)

{

	struct inode *inode = file->f_path.dentry->d_inode;

	struct fuse_conn *fc = get_fuse_conn(inode);

	struct fuse_req *req;

	struct fuse_forget_in inarg;



	memset(&inarg, 0, sizeof(inarg));

	inarg.nlookup = 1;

	req = fuse_get_req_nofail(fc, file);

	req->in.h.opcode = FUSE_FORGET;

	req->in.h.nodeid = nodeid;

	req->in.numargs = 1;

	req->in.args[0].size = sizeof(inarg);

	req->in.args[0].value = &inarg;

	req->isreply = 0;

	fuse_request_send_nowait(fc, req);

}



/*

 * Lock the request.  Up to the next unlock_request() there mustn't be

 * anything that could cause a page-fault.  If the request was already

fs/fuse/dir.c

+156 −4
Original line number Diff line number Diff line
@@ -1155,6 +1155,143 @@ static int parse_dirfile(char *buf, size_t nbytes, struct file *file, 
	return 0;

}



static int fuse_direntplus_link(struct file *file,

				struct fuse_direntplus *direntplus,

				u64 attr_version)

{

	int err;

	struct fuse_entry_out *o = &direntplus->entry_out;

	struct fuse_dirent *dirent = &direntplus->dirent;

	struct dentry *parent = file->f_path.dentry;

	struct qstr name = QSTR_INIT(dirent->name, dirent->namelen);

	struct dentry *dentry;

	struct dentry *alias;

	struct inode *dir = parent->d_inode;

	struct fuse_conn *fc;

	struct inode *inode;



	if (!o->nodeid) {

		/*

		 * Unlike in the case of fuse_lookup, zero nodeid does not mean

		 * ENOENT. Instead, it only means the userspace filesystem did

		 * not want to return attributes/handle for this entry.

		 *

		 * So do nothing.

		 */

		return 0;

	}



	if (name.name[0] == '.') {

		/*

		 * We could potentially refresh the attributes of the directory

		 * and its parent?

		 */

		if (name.len == 1)

			return 0;

		if (name.name[1] == '.' && name.len == 2)

			return 0;

	}

	fc = get_fuse_conn(dir);



	name.hash = full_name_hash(name.name, name.len);

	dentry = d_lookup(parent, &name);

	if (dentry && dentry->d_inode) {

		inode = dentry->d_inode;

		if (get_node_id(inode) == o->nodeid) {

			struct fuse_inode *fi;

			fi = get_fuse_inode(inode);

			spin_lock(&fc->lock);

			fi->nlookup++;

			spin_unlock(&fc->lock);



			/*

			 * The other branch to 'found' comes via fuse_iget()

			 * which bumps nlookup inside

			 */

			goto found;

		}

		err = d_invalidate(dentry);

		if (err)

			goto out;

		dput(dentry);

		dentry = NULL;

	}



	dentry = d_alloc(parent, &name);

	err = -ENOMEM;

	if (!dentry)

		goto out;



	inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,

			  &o->attr, entry_attr_timeout(o), attr_version);

	if (!inode)

		goto out;



	alias = d_materialise_unique(dentry, inode);

	err = PTR_ERR(alias);

	if (IS_ERR(alias))

		goto out;

	if (alias) {

		dput(dentry);

		dentry = alias;

	}



found:

	fuse_change_attributes(inode, &o->attr, entry_attr_timeout(o),

			       attr_version);



	fuse_change_entry_timeout(dentry, o);



	err = 0;

out:

	if (dentry)

		dput(dentry);

	return err;

}



static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,

			     void *dstbuf, filldir_t filldir, u64 attr_version)

{

	struct fuse_direntplus *direntplus;

	struct fuse_dirent *dirent;

	size_t reclen;

	int over = 0;

	int ret;



	while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {

		direntplus = (struct fuse_direntplus *) buf;

		dirent = &direntplus->dirent;

		reclen = FUSE_DIRENTPLUS_SIZE(direntplus);



		if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)

			return -EIO;

		if (reclen > nbytes)

			break;



		if (!over) {

			/* We fill entries into dstbuf only as much as

			   it can hold. But we still continue iterating

			   over remaining entries to link them. If not,

			   we need to send a FORGET for each of those

			   which we did not link.

			*/

			over = filldir(dstbuf, dirent->name, dirent->namelen,

				       file->f_pos, dirent->ino,

				       dirent->type);

			file->f_pos = dirent->off;

		}



		buf += reclen;

		nbytes -= reclen;



		ret = fuse_direntplus_link(file, direntplus, attr_version);

		if (ret)

			fuse_force_forget(file, direntplus->entry_out.nodeid);

	}



	return 0;

}



static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)

{

	int err;
@@ -1163,6 +1300,7 @@ static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir) 
	struct inode *inode = file->f_path.dentry->d_inode;

	struct fuse_conn *fc = get_fuse_conn(inode);

	struct fuse_req *req;

	u64 attr_version = 0;



	if (is_bad_inode(inode))

		return -EIO;
@@ -1179,14 +1317,28 @@ static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir) 
	req->out.argpages = 1;

	req->num_pages = 1;

	req->pages[0] = page;

	fuse_read_fill(req, file, file->f_pos, PAGE_SIZE, FUSE_READDIR);

	if (fc->do_readdirplus) {

		attr_version = fuse_get_attr_version(fc);

		fuse_read_fill(req, file, file->f_pos, PAGE_SIZE,

			       FUSE_READDIRPLUS);

	} else {

		fuse_read_fill(req, file, file->f_pos, PAGE_SIZE,

			       FUSE_READDIR);

	}

	fuse_request_send(fc, req);

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

	err = req->out.h.error;

	fuse_put_request(fc, req);

	if (!err)

		err = parse_dirfile(page_address(page), nbytes, file, dstbuf,

				    filldir);

	if (!err) {

		if (fc->do_readdirplus) {

			err = parse_dirplusfile(page_address(page), nbytes,

						file, dstbuf, filldir,

						attr_version);

		} else {

			err = parse_dirfile(page_address(page), nbytes, file,

					    dstbuf, filldir);

		}

	}



	__free_page(page);

	fuse_invalidate_attr(inode); /* atime changed */

fs/fuse/fuse_i.h

+6 −0
Original line number Diff line number Diff line
@@ -487,6 +487,9 @@ struct fuse_conn { 
	/** Use enhanced/automatic page cache invalidation. */

	unsigned auto_inval_data:1;



	/** Does the filesystem support readdir-plus? */

	unsigned do_readdirplus:1;



	/** The number of requests waiting for completion */

	atomic_t num_waiting;
@@ -578,6 +581,9 @@ void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 


struct fuse_forget_link *fuse_alloc_forget(void);



/* Used by READDIRPLUS */

void fuse_force_forget(struct file *file, u64 nodeid);



/**

 * Initialize READ or READDIR request

 */

fs/fuse/inode.c

+4 −1
Original line number Diff line number Diff line
@@ -863,6 +863,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 
				fc->dont_mask = 1;

			if (arg->flags & FUSE_AUTO_INVAL_DATA)

				fc->auto_inval_data = 1;

			if (arg->flags & FUSE_DO_READDIRPLUS)

				fc->do_readdirplus = 1;

		} else {

			ra_pages = fc->max_read / PAGE_CACHE_SIZE;

			fc->no_lock = 1;
@@ -889,7 +891,8 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 
	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |

		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |

		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |

		FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA;

		FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |

		FUSE_DO_READDIRPLUS;

	req->in.h.opcode = FUSE_INIT;

	req->in.numargs = 1;

	req->in.args[0].size = sizeof(*arg);

include/uapi/linux/fuse.h

+12 −0
Original line number Diff line number Diff line
@@ -193,6 +193,7 @@ struct fuse_file_lock { 
#define FUSE_FLOCK_LOCKS	(1 << 10)

#define FUSE_HAS_IOCTL_DIR	(1 << 11)

#define FUSE_AUTO_INVAL_DATA	(1 << 12)

#define FUSE_DO_READDIRPLUS	(1 << 13)



/**

 * CUSE INIT request/reply flags
@@ -299,6 +300,7 @@ enum fuse_opcode { 
	FUSE_NOTIFY_REPLY  = 41,

	FUSE_BATCH_FORGET  = 42,

	FUSE_FALLOCATE     = 43,

	FUSE_READDIRPLUS   = 44,



	/* CUSE specific operations */

	CUSE_INIT          = 4096,
@@ -630,6 +632,16 @@ struct fuse_dirent { 
#define FUSE_DIRENT_SIZE(d) \

	FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen)



struct fuse_direntplus {

	struct fuse_entry_out entry_out;

	struct fuse_dirent dirent;

};



#define FUSE_NAME_OFFSET_DIRENTPLUS \

	offsetof(struct fuse_direntplus, dirent.name)

#define FUSE_DIRENTPLUS_SIZE(d) \

	FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET_DIRENTPLUS + (d)->dirent.namelen)



struct fuse_notify_inval_inode_out {

	__u64	ino;

	__s64	off;

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