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Commit 3b463ae0 authored by John Muir's avatar John Muir Committed by Miklos Szeredi
Browse files

fuse: invalidation reverse calls 



Add notification messages that allow the filesystem to invalidate VFS
caches.

Two notifications are added:

 1) inode invalidation

   - invalidate cached attributes
   - invalidate a range of pages in the page cache (this is optional)

 2) dentry invalidation

   - try to invalidate a subtree in the dentry cache

Care must be taken while accessing the 'struct super_block' for the
mount, as it can go away while an invalidation is in progress.  To
prevent this, introduce a rw-semaphore, that is taken for read during
the invalidation and taken for write in the ->kill_sb callback.

Cc: Csaba Henk <csaba@gluster.com>
Cc: Anand Avati <avati@zresearch.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent e0a43ddc

fs/fuse/dev.c

+81 −0
Original line number Diff line number Diff line
@@ -849,6 +849,81 @@ err: 
	return err;

}



static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,

				   struct fuse_copy_state *cs)

{

	struct fuse_notify_inval_inode_out outarg;

	int err = -EINVAL;



	if (size != sizeof(outarg))

		goto err;



	err = fuse_copy_one(cs, &outarg, sizeof(outarg));

	if (err)

		goto err;

	fuse_copy_finish(cs);



	down_read(&fc->killsb);

	err = -ENOENT;

	if (!fc->sb)

		goto err_unlock;



	err = fuse_reverse_inval_inode(fc->sb, outarg.ino,

				       outarg.off, outarg.len);



err_unlock:

	up_read(&fc->killsb);

	return err;



err:

	fuse_copy_finish(cs);

	return err;

}



static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,

				   struct fuse_copy_state *cs)

{

	struct fuse_notify_inval_entry_out outarg;

	int err = -EINVAL;

	char buf[FUSE_NAME_MAX+1];

	struct qstr name;



	if (size < sizeof(outarg))

		goto err;



	err = fuse_copy_one(cs, &outarg, sizeof(outarg));

	if (err)

		goto err;



	err = -ENAMETOOLONG;

	if (outarg.namelen > FUSE_NAME_MAX)

		goto err;



	name.name = buf;

	name.len = outarg.namelen;

	err = fuse_copy_one(cs, buf, outarg.namelen + 1);

	if (err)

		goto err;

	fuse_copy_finish(cs);

	buf[outarg.namelen] = 0;

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



	down_read(&fc->killsb);

	err = -ENOENT;

	if (!fc->sb)

		goto err_unlock;



	err = fuse_reverse_inval_entry(fc->sb, outarg.parent, &name);



err_unlock:

	up_read(&fc->killsb);

	return err;



err:

	fuse_copy_finish(cs);

	return err;

}



static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,

		       unsigned int size, struct fuse_copy_state *cs)

{
@@ -856,6 +931,12 @@ static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 
	case FUSE_NOTIFY_POLL:

		return fuse_notify_poll(fc, size, cs);



	case FUSE_NOTIFY_INVAL_INODE:

		return fuse_notify_inval_inode(fc, size, cs);



	case FUSE_NOTIFY_INVAL_ENTRY:

		return fuse_notify_inval_entry(fc, size, cs);



	default:

		fuse_copy_finish(cs);

		return -EINVAL;

fs/fuse/dir.c

+37 −0
Original line number Diff line number Diff line
@@ -859,6 +859,43 @@ int fuse_update_attributes(struct inode *inode, struct kstat *stat, 
	return err;

}



int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,

			     struct qstr *name)

{

	int err = -ENOTDIR;

	struct inode *parent;

	struct dentry *dir;

	struct dentry *entry;



	parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid);

	if (!parent)

		return -ENOENT;



	mutex_lock(&parent->i_mutex);

	if (!S_ISDIR(parent->i_mode))

		goto unlock;



	err = -ENOENT;

	dir = d_find_alias(parent);

	if (!dir)

		goto unlock;



	entry = d_lookup(dir, name);

	dput(dir);

	if (!entry)

		goto unlock;



	fuse_invalidate_attr(parent);

	fuse_invalidate_entry(entry);

	dput(entry);

	err = 0;



 unlock:

	mutex_unlock(&parent->i_mutex);

	iput(parent);

	return err;

}



/*

 * Calling into a user-controlled filesystem gives the filesystem

 * daemon ptrace-like capabilities over the requester process.  This

fs/fuse/fuse_i.h

+24 −0
Original line number Diff line number Diff line
@@ -484,6 +484,12 @@ struct fuse_conn { 


	/** Called on final put */

	void (*release)(struct fuse_conn *);



	/** Super block for this connection. */

	struct super_block *sb;



	/** Read/write semaphore to hold when accessing sb. */

	struct rw_semaphore killsb;

};



static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
@@ -511,6 +517,11 @@ extern const struct file_operations fuse_dev_operations; 


extern const struct dentry_operations fuse_dentry_operations;



/**

 * Inode to nodeid comparison.

 */

int fuse_inode_eq(struct inode *inode, void *_nodeidp);



/**

 * Get a filled in inode

 */
@@ -711,6 +722,19 @@ void fuse_release_nowrite(struct inode *inode); 


u64 fuse_get_attr_version(struct fuse_conn *fc);



/**

 * File-system tells the kernel to invalidate cache for the given node id.

 */

int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,

			     loff_t offset, loff_t len);



/**

 * File-system tells the kernel to invalidate parent attributes and

 * the dentry matching parent/name.

 */

int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,

			     struct qstr *name);



int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,

		 bool isdir);

ssize_t fuse_direct_io(struct file *file, const char __user *buf,

fs/fuse/inode.c

+56 −3
Original line number Diff line number Diff line
@@ -206,7 +206,7 @@ static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 
		BUG();

}



static int fuse_inode_eq(struct inode *inode, void *_nodeidp)

int fuse_inode_eq(struct inode *inode, void *_nodeidp)

{

	u64 nodeid = *(u64 *) _nodeidp;

	if (get_node_id(inode) == nodeid)
@@ -257,6 +257,31 @@ struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 
	return inode;

}



int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,

			     loff_t offset, loff_t len)

{

	struct inode *inode;

	pgoff_t pg_start;

	pgoff_t pg_end;



	inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);

	if (!inode)

		return -ENOENT;



	fuse_invalidate_attr(inode);

	if (offset >= 0) {

		pg_start = offset >> PAGE_CACHE_SHIFT;

		if (len <= 0)

			pg_end = -1;

		else

			pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;

		invalidate_inode_pages2_range(inode->i_mapping,

					      pg_start, pg_end);

	}

	iput(inode);

	return 0;

}



static void fuse_umount_begin(struct super_block *sb)

{

	fuse_abort_conn(get_fuse_conn_super(sb));
@@ -480,6 +505,7 @@ void fuse_conn_init(struct fuse_conn *fc) 
	memset(fc, 0, sizeof(*fc));

	spin_lock_init(&fc->lock);

	mutex_init(&fc->inst_mutex);

	init_rwsem(&fc->killsb);

	atomic_set(&fc->count, 1);

	init_waitqueue_head(&fc->waitq);

	init_waitqueue_head(&fc->blocked_waitq);
@@ -862,6 +888,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) 
	fuse_conn_init(fc);



	fc->dev = sb->s_dev;

	fc->sb = sb;

	err = fuse_bdi_init(fc, sb);

	if (err)

		goto err_put_conn;
@@ -948,12 +975,25 @@ static int fuse_get_sb(struct file_system_type *fs_type, 
	return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt);

}



static void fuse_kill_sb_anon(struct super_block *sb)

{

	struct fuse_conn *fc = get_fuse_conn_super(sb);



	if (fc) {

		down_write(&fc->killsb);

		fc->sb = NULL;

		up_write(&fc->killsb);

	}



	kill_anon_super(sb);

}



static struct file_system_type fuse_fs_type = {

	.owner		= THIS_MODULE,

	.name		= "fuse",

	.fs_flags	= FS_HAS_SUBTYPE,

	.get_sb		= fuse_get_sb,

	.kill_sb	= kill_anon_super,

	.kill_sb	= fuse_kill_sb_anon,

};



#ifdef CONFIG_BLOCK
@@ -965,11 +1005,24 @@ static int fuse_get_sb_blk(struct file_system_type *fs_type, 
			   mnt);

}



static void fuse_kill_sb_blk(struct super_block *sb)

{

	struct fuse_conn *fc = get_fuse_conn_super(sb);



	if (fc) {

		down_write(&fc->killsb);

		fc->sb = NULL;

		up_write(&fc->killsb);

	}



	kill_block_super(sb);

}



static struct file_system_type fuseblk_fs_type = {

	.owner		= THIS_MODULE,

	.name		= "fuseblk",

	.get_sb		= fuse_get_sb_blk,

	.kill_sb	= kill_block_super,

	.kill_sb	= fuse_kill_sb_blk,

	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,

};

include/linux/fuse.h

+16 −0
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ 
 *

 * 7.12

 *  - add umask flag to input argument of open, mknod and mkdir

 *  - add notification messages for invalidation of inodes and

 *    directory entries

 */



#ifndef _LINUX_FUSE_H
@@ -229,6 +231,8 @@ enum fuse_opcode { 


enum fuse_notify_code {

	FUSE_NOTIFY_POLL   = 1,

	FUSE_NOTIFY_INVAL_INODE = 2,

	FUSE_NOTIFY_INVAL_ENTRY = 3,

	FUSE_NOTIFY_CODE_MAX,

};
@@ -524,4 +528,16 @@ struct fuse_dirent { 
#define FUSE_DIRENT_SIZE(d) \

	FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen)



struct fuse_notify_inval_inode_out {

	__u64	ino;

	__s64	off;

	__s64	len;

};



struct fuse_notify_inval_entry_out {

	__u64	parent;

	__u32	namelen;

	__u32	padding;

};



#endif /* _LINUX_FUSE_H */