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Commit 5f5733b8 authored by Daniel Rosenberg's avatar Daniel Rosenberg
Browse files

ANDROID: sdcardfs: Fix case insensitive lookup 



The previous case insensitive lookup relied on the
entry being present in the dcache. This instead uses
iterate_dir to find the correct case.

Signed-off-by: default avatarDaniel Rosenberg <drosen@google.com>
bug: 35633782
Change-Id: I556f7090773468c1943c89a5e2aa07f746ba49c5
parent abb2b2b9

fs/sdcardfs/lookup.c

+51 −17
Original line number Diff line number Diff line
@@ -206,6 +206,28 @@ int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb, 
	return err;

}



struct sdcardfs_name_data {

	struct dir_context ctx;

	const struct qstr *to_find;

	char *name;

	bool found;

};



static int sdcardfs_name_match(struct dir_context *ctx, const char *name, int namelen,

		loff_t offset, u64 ino, unsigned int d_type)

{

	struct sdcardfs_name_data *buf = container_of(ctx, struct sdcardfs_name_data, ctx);

	struct qstr candidate = QSTR_INIT(name, namelen);



	if (qstr_case_eq(buf->to_find, &candidate)) {

		memcpy(buf->name, name, namelen);

		buf->name[namelen] = 0;

		buf->found = true;

		return 1;

	}

	return 0;

}



/*

 * Main driver function for sdcardfs's lookup.

 *
@@ -242,27 +264,39 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry, 
				&lower_path);

	/* check for other cases */

	if (err == -ENOENT) {

		struct dentry *child;

		struct dentry *match = NULL;

		inode_lock(d_inode(lower_dir_dentry));

		spin_lock(&lower_dir_dentry->d_lock);

		list_for_each_entry(child, &lower_dir_dentry->d_subdirs, d_child) {

			if (child && d_inode(child)) {

				if (qstr_case_eq(&child->d_name, name)) {

					match = dget(child);

					break;

				}

		struct file *file;

		const struct cred *cred = current_cred();



		struct sdcardfs_name_data buffer = {

			.ctx.actor = sdcardfs_name_match,

			.to_find = name,

			.name = __getname(),

			.found = false,

		};



		if (!buffer.name) {

			err = -ENOMEM;

			goto out;

		}

		file = dentry_open(lower_parent_path, O_RDONLY, cred);

		if (IS_ERR(file)) {

			err = PTR_ERR(file);

			goto put_name;

		}

		spin_unlock(&lower_dir_dentry->d_lock);

		inode_unlock(d_inode(lower_dir_dentry));

		if (match) {

		err = iterate_dir(file, &buffer.ctx);

		fput(file);

		if (err)

			goto put_name;



		if (buffer.found)

			err = vfs_path_lookup(lower_dir_dentry,

						lower_dir_mnt,

						match->d_name.name, 0,

						buffer.name, 0,

						&lower_path);

			dput(match);

		}

		else

			err = -ENOENT;

put_name:

		__putname(buffer.name);

	}



	/* no error: handle positive dentries */