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Commit 5c672ab3 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

fuse: serialize dirops by default 



Negotiate with userspace filesystems whether they support parallel readdir
and lookup.  Disable parallelism by default for fear of breaking fuse
filesystems.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Fixes: 9902af79 ("parallel lookups: actual switch to rwsem")
Fixes: d9b3dbdc ("fuse: switch to ->iterate_shared()")
parent 4c2e07c6

fs/fuse/dir.c

+4 −0
Original line number Diff line number Diff line
@@ -341,8 +341,10 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry, 
	struct dentry *newent;

	bool outarg_valid = true;



	fuse_lock_inode(dir);

	err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,

			       &outarg, &inode);

	fuse_unlock_inode(dir);

	if (err == -ENOENT) {

		outarg_valid = false;

		err = 0;
@@ -1341,7 +1343,9 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx) 
		fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,

			       FUSE_READDIR);

	}

	fuse_lock_inode(inode);

	fuse_request_send(fc, req);

	fuse_unlock_inode(inode);

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

	err = req->out.h.error;

	fuse_put_request(fc, req);

fs/fuse/fuse_i.h

+9 −0
Original line number Diff line number Diff line
@@ -110,6 +110,9 @@ struct fuse_inode { 


	/** Miscellaneous bits describing inode state */

	unsigned long state;



	/** Lock for serializing lookup and readdir for back compatibility*/

	struct mutex mutex;

};



/** FUSE inode state bits */
@@ -540,6 +543,9 @@ struct fuse_conn { 
	/** write-back cache policy (default is write-through) */

	unsigned writeback_cache:1;



	/** allow parallel lookups and readdir (default is serialized) */

	unsigned parallel_dirops:1;



	/*

	 * The following bitfields are only for optimization purposes

	 * and hence races in setting them will not cause malfunction
@@ -956,4 +962,7 @@ int fuse_do_setattr(struct inode *inode, struct iattr *attr, 


void fuse_set_initialized(struct fuse_conn *fc);



void fuse_unlock_inode(struct inode *inode);

void fuse_lock_inode(struct inode *inode);



#endif /* _FS_FUSE_I_H */

fs/fuse/inode.c

+18 −1
Original line number Diff line number Diff line
@@ -97,6 +97,7 @@ static struct inode *fuse_alloc_inode(struct super_block *sb) 
	INIT_LIST_HEAD(&fi->queued_writes);

	INIT_LIST_HEAD(&fi->writepages);

	init_waitqueue_head(&fi->page_waitq);

	mutex_init(&fi->mutex);

	fi->forget = fuse_alloc_forget();

	if (!fi->forget) {

		kmem_cache_free(fuse_inode_cachep, inode);
@@ -117,6 +118,7 @@ static void fuse_destroy_inode(struct inode *inode) 
	struct fuse_inode *fi = get_fuse_inode(inode);

	BUG_ON(!list_empty(&fi->write_files));

	BUG_ON(!list_empty(&fi->queued_writes));

	mutex_destroy(&fi->mutex);

	kfree(fi->forget);

	call_rcu(&inode->i_rcu, fuse_i_callback);

}
@@ -351,6 +353,18 @@ int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 
	return 0;

}



void fuse_lock_inode(struct inode *inode)

{

	if (!get_fuse_conn(inode)->parallel_dirops)

		mutex_lock(&get_fuse_inode(inode)->mutex);

}



void fuse_unlock_inode(struct inode *inode)

{

	if (!get_fuse_conn(inode)->parallel_dirops)

		mutex_unlock(&get_fuse_inode(inode)->mutex);

}



static void fuse_umount_begin(struct super_block *sb)

{

	fuse_abort_conn(get_fuse_conn_super(sb));
@@ -898,6 +912,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 
				fc->async_dio = 1;

			if (arg->flags & FUSE_WRITEBACK_CACHE)

				fc->writeback_cache = 1;

			if (arg->flags & FUSE_PARALLEL_DIROPS)

				fc->parallel_dirops = 1;

			if (arg->time_gran && arg->time_gran <= 1000000000)

				fc->sb->s_time_gran = arg->time_gran;

		} else {
@@ -928,7 +944,8 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 
		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |

		FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |

		FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |

		FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT;

		FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |

		FUSE_PARALLEL_DIROPS;

	req->in.h.opcode = FUSE_INIT;

	req->in.numargs = 1;

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

include/uapi/linux/fuse.h

+6 −1
Original line number Diff line number Diff line
@@ -105,6 +105,9 @@ 
 *

 *  7.24

 *  - add FUSE_LSEEK for SEEK_HOLE and SEEK_DATA support

 *

 *  7.25

 *  - add FUSE_PARALLEL_DIROPS

 */



#ifndef _LINUX_FUSE_H
@@ -140,7 +143,7 @@ 
#define FUSE_KERNEL_VERSION 7



/** Minor version number of this interface */

#define FUSE_KERNEL_MINOR_VERSION 24

#define FUSE_KERNEL_MINOR_VERSION 25



/** The node ID of the root inode */

#define FUSE_ROOT_ID 1
@@ -234,6 +237,7 @@ struct fuse_file_lock { 
 * FUSE_ASYNC_DIO: asynchronous direct I/O submission

 * FUSE_WRITEBACK_CACHE: use writeback cache for buffered writes

 * FUSE_NO_OPEN_SUPPORT: kernel supports zero-message opens

 * FUSE_PARALLEL_DIROPS: allow parallel lookups and readdir

 */

#define FUSE_ASYNC_READ		(1 << 0)

#define FUSE_POSIX_LOCKS	(1 << 1)
@@ -253,6 +257,7 @@ struct fuse_file_lock { 
#define FUSE_ASYNC_DIO		(1 << 15)

#define FUSE_WRITEBACK_CACHE	(1 << 16)

#define FUSE_NO_OPEN_SUPPORT	(1 << 17)

#define FUSE_PARALLEL_DIROPS    (1 << 18)



/**

 * CUSE INIT request/reply flags