Commit d9b9f8d5 authored by Eric Biggers's avatar Eric Biggers Committed by Theodore Ts'o
Browse files

ext4: clean up ext4_match() and callers 



When ext4 encryption was originally merged, we were encrypting the
user-specified filename in ext4_match(), introducing a lot of additional
complexity into ext4_match() and its callers.  This has since been
changed to encrypt the filename earlier, so we can remove the gunk
that's no longer needed.  This more or less reverts ext4_search_dir()
and ext4_find_dest_de() to the way they were in the v4.0 kernel.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 1f73d491

fs/ext4/namei.c

+25 −56
Original line number Diff line number Diff line
@@ -1237,18 +1237,17 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block) 
}



/*

 * NOTE! unlike strncmp, ext4_match returns 1 for success, 0 for failure.

 * Test whether a directory entry matches the filename being searched for.

 *

 * `len <= EXT4_NAME_LEN' is guaranteed by caller.

 * `de != NULL' is guaranteed by caller.

 * Return: %true if the directory entry matches, otherwise %false.

 */

static inline int ext4_match(struct ext4_filename *fname,

			     struct ext4_dir_entry_2 *de)

static inline bool ext4_match(const struct ext4_filename *fname,

			      const struct ext4_dir_entry_2 *de)

{

	struct fscrypt_name f;



	if (!de->inode)

		return 0;

		return false;



	f.usr_fname = fname->usr_fname;

	f.disk_name = fname->disk_name;
@@ -1269,48 +1268,31 @@ int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size, 
	struct ext4_dir_entry_2 * de;

	char * dlimit;

	int de_len;

	int res;



	de = (struct ext4_dir_entry_2 *)search_buf;

	dlimit = search_buf + buf_size;

	while ((char *) de < dlimit) {

		/* this code is executed quadratically often */

		/* do minimal checking `by hand' */

		if ((char *) de + de->name_len <= dlimit) {

			res = ext4_match(fname, de);

			if (res < 0) {

				res = -1;

				goto return_result;

			}

			if (res > 0) {

		if ((char *) de + de->name_len <= dlimit &&

		    ext4_match(fname, de)) {

			/* found a match - just to be sure, do

			 * a full check */

				if (ext4_check_dir_entry(dir, NULL, de, bh,

						bh->b_data,

						 bh->b_size, offset)) {

					res = -1;

					goto return_result;

				}

			if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,

						 bh->b_size, offset))

				return -1;

			*res_dir = de;

				res = 1;

				goto return_result;

			}



			return 1;

		}

		/* prevent looping on a bad block */

		de_len = ext4_rec_len_from_disk(de->rec_len,

						dir->i_sb->s_blocksize);

		if (de_len <= 0) {

			res = -1;

			goto return_result;

		}

		if (de_len <= 0)

			return -1;

		offset += de_len;

		de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);

	}



	res = 0;

return_result:

	return res;

	return 0;

}



static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
@@ -1814,24 +1796,15 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode, 
	int nlen, rlen;

	unsigned int offset = 0;

	char *top;

	int res;



	de = (struct ext4_dir_entry_2 *)buf;

	top = buf + buf_size - reclen;

	while ((char *) de <= top) {

		if (ext4_check_dir_entry(dir, NULL, de, bh,

					 buf, buf_size, offset)) {

			res = -EFSCORRUPTED;

			goto return_result;

		}

		/* Provide crypto context and crypto buffer to ext4 match */

		res = ext4_match(fname, de);

		if (res < 0)

			goto return_result;

		if (res > 0) {

			res = -EEXIST;

			goto return_result;

		}

					 buf, buf_size, offset))

			return -EFSCORRUPTED;

		if (ext4_match(fname, de))

			return -EEXIST;

		nlen = EXT4_DIR_REC_LEN(de->name_len);

		rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);

		if ((de->inode ? rlen - nlen : rlen) >= reclen)
@@ -1839,15 +1812,11 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode, 
		de = (struct ext4_dir_entry_2 *)((char *)de + rlen);

		offset += rlen;

	}



	if ((char *) de > top)

		res = -ENOSPC;

	else {

		return -ENOSPC;



	*dest_de = de;

		res = 0;

	}

return_result:

	return res;

	return 0;

}



int ext4_insert_dentry(struct inode *dir,

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