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Commit 8ee6059c authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

ovl: simplify lookup 



If encountering a non-directory, then stop looking at lower layers.

In this case the oe->opaque flag is not set anymore, which doesn't matter
since existence of lower file is now checked at remove/rename time.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 3ee23ff1

fs/overlayfs/super.c

+25 −29
Original line number Diff line number Diff line
@@ -473,7 +473,9 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 
	unsigned int ctr = 0;

	struct inode *inode = NULL;

	bool upperopaque = false;

	struct dentry *this, *prev = NULL;

	bool stop = false;

	bool isdir = false;

	struct dentry *this;

	unsigned int i;

	int err;
@@ -494,23 +496,26 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 
			if (ovl_is_whiteout(this)) {

				dput(this);

				this = NULL;

				upperopaque = true;

			} else if (poe->numlower && ovl_is_opaquedir(this)) {

				upperopaque = true;

				stop = upperopaque = true;

			} else if (!d_is_dir(this)) {

				stop = true;

			} else {

				isdir = true;

				if (poe->numlower && ovl_is_opaquedir(this))

					stop = upperopaque = true;

			}

		}

		upperdentry = prev = this;

		upperdentry = this;

	}



	if (!upperopaque && poe->numlower) {

	if (!stop && poe->numlower) {

		err = -ENOMEM;

		stack = kcalloc(poe->numlower, sizeof(struct path), GFP_KERNEL);

		if (!stack)

			goto out_put_upper;

	}



	for (i = 0; !upperopaque && i < poe->numlower; i++) {

		bool opaque = false;

	for (i = 0; !stop && i < poe->numlower; i++) {

		struct path lowerpath = poe->lowerstack[i];



		this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name);
@@ -530,35 +535,26 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 
			break;

		}

		/*

		 * Only makes sense to check opaque dir if this is not the

		 * lowermost layer.

		 */

		if (i < poe->numlower - 1 && ovl_is_opaquedir(this))

			opaque = true;



		if (prev && (!S_ISDIR(prev->d_inode->i_mode) ||

			     !S_ISDIR(this->d_inode->i_mode))) {

			/*

			 * FIXME: check for upper-opaqueness maybe better done

			 * in remove code.

		 * If this is a non-directory then stop here.

		 */

			if (prev == upperdentry)

				upperopaque = true;

		if (!d_is_dir(this)) {

			if (isdir) {

				dput(this);

				break;

			}

			stop = true;

		} else {

			/*

		 * If this is a non-directory then stop here.

			 * Only makes sense to check opaque dir if this is not

			 * the lowermost layer.

			 */

		if (!S_ISDIR(this->d_inode->i_mode))

			opaque = true;

			if (i < poe->numlower - 1 && ovl_is_opaquedir(this))

				stop = true;

		}



		stack[ctr].dentry = this;

		stack[ctr].mnt = lowerpath.mnt;

		ctr++;

		prev = this;

		if (opaque)

			break;

	}



	oe = ovl_alloc_entry(ctr);