Commit b1b72ac2 authored by Guan-Chun Wu's avatar Guan-Chun Wu Committed by Andrew Morton
Browse files

ceph: replace local base64 helpers with lib/base64 

Remove the ceph_base64_encode() and ceph_base64_decode() functions and
replace their usage with the generic base64_encode() and base64_decode()
helpers from lib/base64.

This eliminates the custom implementation in Ceph, reduces code
duplication, and relies on the shared Base64 code in lib.  The helpers
preserve RFC 3501-compliant Base64 encoding without padding, so there are
no functional changes.

This change also improves performance: encoding is about 2.7x faster and
decoding achieves 43-52x speedups compared to the previous local
implementation.

Link: https://lkml.kernel.org/r/20251114060240.89965-1-409411716@gms.tku.edu.tw


Signed-off-by: default avatarGuan-Chun Wu <409411716@gms.tku.edu.tw>
Reviewed-by: default avatarKuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: default avatarViacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Yu-Sheng Huang <home7438072@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7794510e

fs/ceph/crypto.c

+4 −56
Original line number Diff line number Diff line
@@ -15,59 +15,6 @@ 
#include "mds_client.h"

#include "crypto.h"



/*

 * The base64url encoding used by fscrypt includes the '_' character, which may

 * cause problems in snapshot names (which can not start with '_').  Thus, we

 * used the base64 encoding defined for IMAP mailbox names (RFC 3501) instead,

 * which replaces '-' and '_' by '+' and ','.

 */

static const char base64_table[65] =

	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";



int ceph_base64_encode(const u8 *src, int srclen, char *dst)

{

	u32 ac = 0;

	int bits = 0;

	int i;

	char *cp = dst;



	for (i = 0; i < srclen; i++) {

		ac = (ac << 8) | src[i];

		bits += 8;

		do {

			bits -= 6;

			*cp++ = base64_table[(ac >> bits) & 0x3f];

		} while (bits >= 6);

	}

	if (bits)

		*cp++ = base64_table[(ac << (6 - bits)) & 0x3f];

	return cp - dst;

}



int ceph_base64_decode(const char *src, int srclen, u8 *dst)

{

	u32 ac = 0;

	int bits = 0;

	int i;

	u8 *bp = dst;



	for (i = 0; i < srclen; i++) {

		const char *p = strchr(base64_table, src[i]);



		if (p == NULL || src[i] == 0)

			return -1;

		ac = (ac << 6) | (p - base64_table);

		bits += 6;

		if (bits >= 8) {

			bits -= 8;

			*bp++ = (u8)(ac >> bits);

		}

	}

	if (ac & ((1 << bits) - 1))

		return -1;

	return bp - dst;

}



static int ceph_crypt_get_context(struct inode *inode, void *ctx, size_t len)

{

	struct ceph_inode_info *ci = ceph_inode(inode);
@@ -318,7 +265,7 @@ int ceph_encode_encrypted_dname(struct inode *parent, char *buf, int elen) 
	}



	/* base64 encode the encrypted name */

	elen = ceph_base64_encode(cryptbuf, len, p);

	elen = base64_encode(cryptbuf, len, p, false, BASE64_IMAP);

	doutc(cl, "base64-encoded ciphertext name = %.*s\n", elen, p);



	/* To understand the 240 limit, see CEPH_NOHASH_NAME_MAX comments */
@@ -412,7 +359,8 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, 
			tname = &_tname;

		}



		declen = ceph_base64_decode(name, name_len, tname->name);

		declen = base64_decode(name, name_len,

				       tname->name, false, BASE64_IMAP);

		if (declen <= 0) {

			ret = -EIO;

			goto out;
@@ -426,7 +374,7 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, 


	ret = fscrypt_fname_disk_to_usr(dir, 0, 0, &iname, oname);

	if (!ret && (dir != fname->dir)) {

		char tmp_buf[CEPH_BASE64_CHARS(NAME_MAX)];

		char tmp_buf[BASE64_CHARS(NAME_MAX)];



		name_len = snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld",

				    oname->len, oname->name, dir->i_ino);

fs/ceph/crypto.h

+1 −5
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 


#include <crypto/sha2.h>

#include <linux/fscrypt.h>

#include <linux/base64.h>



#define CEPH_FSCRYPT_BLOCK_SHIFT   12

#define CEPH_FSCRYPT_BLOCK_SIZE    (_AC(1, UL) << CEPH_FSCRYPT_BLOCK_SHIFT)
@@ -89,11 +90,6 @@ static inline u32 ceph_fscrypt_auth_len(struct ceph_fscrypt_auth *fa) 
 */

#define CEPH_NOHASH_NAME_MAX (180 - SHA256_DIGEST_SIZE)



#define CEPH_BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3)



int ceph_base64_encode(const u8 *src, int srclen, char *dst);

int ceph_base64_decode(const char *src, int srclen, u8 *dst);



void ceph_fscrypt_set_ops(struct super_block *sb);



void ceph_fscrypt_free_dummy_policy(struct ceph_fs_client *fsc);

fs/ceph/dir.c

+3 −2
Original line number Diff line number Diff line
@@ -998,13 +998,14 @@ static int prep_encrypted_symlink_target(struct ceph_mds_request *req, 
	if (err)

		goto out;



	req->r_path2 = kmalloc(CEPH_BASE64_CHARS(osd_link.len) + 1, GFP_KERNEL);

	req->r_path2 = kmalloc(BASE64_CHARS(osd_link.len) + 1, GFP_KERNEL);

	if (!req->r_path2) {

		err = -ENOMEM;

		goto out;

	}



	len = ceph_base64_encode(osd_link.name, osd_link.len, req->r_path2);

	len = base64_encode(osd_link.name, osd_link.len,

			    req->r_path2, false, BASE64_IMAP);

	req->r_path2[len] = '\0';

out:

	fscrypt_fname_free_buffer(&osd_link);

fs/ceph/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -958,7 +958,7 @@ static int decode_encrypted_symlink(struct ceph_mds_client *mdsc, 
	if (!sym)

		return -ENOMEM;



	declen = ceph_base64_decode(encsym, enclen, sym);

	declen = base64_decode(encsym, enclen, sym, false, BASE64_IMAP);

	if (declen < 0) {

		pr_err_client(cl,

			"can't decode symlink (%d). Content: %.*s\n",