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ceph: replace local base64 helpers with lib/base64

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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: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Reviewed-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Viacheslav 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: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Guan-Chun Wu
2025-11-14 14:02:40 +08:00
committed by Andrew Morton
parent 7794510e20
commit b1b72ac25f
4 changed files with 9 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

60
fs/ceph/crypto.c
View File

@@ -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);

6
fs/ceph/crypto.h
View File

@@ -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);

5
fs/ceph/dir.c
View File

@@ -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);

2
fs/ceph/inode.c
View File

@@ -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",