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Commit 39d3d60a authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
Browse files

ovl: introduce copy up waitqueue 



The overlay sb 'copyup_wq' and overlay inode 'copying' condition
variable are about to replace the upper sb rename_lock, as finer
grained synchronization objects for concurrent copy up.

Suggested-by: default avatarMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent d8514d8e

fs/overlayfs/overlayfs.h

+2 −0
Original line number Diff line number Diff line
@@ -178,6 +178,8 @@ void ovl_dentry_version_inc(struct dentry *dentry); 
u64 ovl_dentry_version_get(struct dentry *dentry);

bool ovl_is_whiteout(struct dentry *dentry);

struct file *ovl_path_open(struct path *path, int flags);

int ovl_copy_up_start(struct dentry *dentry);

void ovl_copy_up_end(struct dentry *dentry);



/* namei.c */

int ovl_path_next(int idx, struct dentry *dentry, struct path *path);

fs/overlayfs/ovl_entry.h

+2 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ struct ovl_fs { 
	/* creds of process who forced instantiation of super block */

	const struct cred *creator_cred;

	bool tmpfile;

	wait_queue_head_t copyup_wq;

};



/* private information held for every overlayfs dentry */
@@ -39,6 +40,7 @@ struct ovl_entry { 
			u64 version;

			const char *redirect;

			bool opaque;

			bool copying;

		};

		struct rcu_head rcu;

	};

fs/overlayfs/super.c

+1 −0
Original line number Diff line number Diff line
@@ -708,6 +708,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
	if (!ufs)

		goto out;



	init_waitqueue_head(&ufs->copyup_wq);

	ufs->config.redirect_dir = ovl_redirect_dir_def;

	err = ovl_parse_opt((char *) data, &ufs->config);

	if (err)

fs/overlayfs/util.c

+30 −0
Original line number Diff line number Diff line
@@ -263,3 +263,33 @@ struct file *ovl_path_open(struct path *path, int flags) 
{

	return dentry_open(path, flags | O_NOATIME, current_cred());

}



int ovl_copy_up_start(struct dentry *dentry)

{

	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;

	struct ovl_entry *oe = dentry->d_fsdata;

	int err;



	spin_lock(&ofs->copyup_wq.lock);

	err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying);

	if (!err) {

		if (oe->__upperdentry)

			err = 1; /* Already copied up */

		else

			oe->copying = true;

	}

	spin_unlock(&ofs->copyup_wq.lock);



	return err;

}



void ovl_copy_up_end(struct dentry *dentry)

{

	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;

	struct ovl_entry *oe = dentry->d_fsdata;



	spin_lock(&ofs->copyup_wq.lock);

	oe->copying = false;

	wake_up_locked(&ofs->copyup_wq);

	spin_unlock(&ofs->copyup_wq.lock);

}