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fscrypt: Remove fs-layer zeroout code

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Now that fscrypt's file contents en/decryption is always implemented
using blk-crypto when the filesystem is block-based, the fs-layer
zeroout code in fs/crypto/bio.c is unused code.  Remove it, then fold
fscrypt_zeroout_range_inline_crypt() into fscrypt_zeroout_range().

Then make fscrypt_alloc_bounce_page() and fscrypt_crypt_data_unit()
static, since they're no longer called from any other file.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260713023708.9245-15-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
This commit is contained in:
Eric Biggers 2026-07-12 22:37:05 -04:00
parent 35f440660f
commit 8c2c9c4063
3 changed files with 32 additions and 121 deletions
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134
fs/crypto/bio.c
View File

@ -69,16 +69,36 @@ static void fscrypt_zeroout_range_end_io(struct bio *bio)
bio_put(bio);
}
static int fscrypt_zeroout_range_inline_crypt(const struct inode *inode,
loff_t pos, sector_t sector,
u64 len)
/**
* fscrypt_zeroout_range() - zero out a range of blocks in an encrypted file
* @inode: the file's inode
* @pos: the first file position (in bytes) to zero out
* @sector: the first sector to zero out
* @len: bytes to zero out
*
* Zero out filesystem blocks in an encrypted regular file on-disk, i.e. write
* ciphertext blocks which decrypt to the all-zeroes block. The blocks must be
* both logically and physically contiguous. It's also assumed that the
* filesystem only uses a single block device, ->s_bdev. @len must be a
* multiple of the file system logical block size.
*
* Note that since each block uses a different IV, this involves writing a
* different ciphertext to each block; we can't simply reuse the same one.
*
* Return: 0 on success; -errno on failure.
*/
int fscrypt_zeroout_range(const struct inode *inode, loff_t pos,
sector_t sector, u64 len)
{
struct fscrypt_zero_done done = {
.pending = ATOMIC_INIT(1),
.done = COMPLETION_INITIALIZER_ONSTACK(done.done),
};
while (len) {
if (len == 0)
return 0;
do {
struct bio *bio;
unsigned int n;
@ -102,115 +122,11 @@ static int fscrypt_zeroout_range_inline_crypt(const struct inode *inode,
atomic_inc(&done.pending);
blk_crypto_submit_bio(bio);
}
} while (len);
fscrypt_zeroout_range_done(&done);
wait_for_completion(&done.done);
return blk_status_to_errno(done.status);
}
/**
* fscrypt_zeroout_range() - zero out a range of blocks in an encrypted file
* @inode: the file's inode
* @pos: the first file position (in bytes) to zero out
* @sector: the first sector to zero out
* @len: bytes to zero out
*
* Zero out filesystem blocks in an encrypted regular file on-disk, i.e. write
* ciphertext blocks which decrypt to the all-zeroes block. The blocks must be
* both logically and physically contiguous. It's also assumed that the
* filesystem only uses a single block device, ->s_bdev. @len must be a
* multiple of the file system logical block size.
*
* Note that since each block uses a different IV, this involves writing a
* different ciphertext to each block; we can't simply reuse the same one.
*
* Return: 0 on success; -errno on failure.
*/
int fscrypt_zeroout_range(const struct inode *inode, loff_t pos,
sector_t sector, u64 len)
{
const struct fscrypt_inode_info *ci = fscrypt_get_inode_info_raw(inode);
const unsigned int du_bits = ci->ci_data_unit_bits;
const unsigned int du_size = 1U << du_bits;
const unsigned int du_per_page_bits = PAGE_SHIFT - du_bits;
const unsigned int du_per_page = 1U << du_per_page_bits;
u64 du_index = pos >> du_bits;
u64 du_remaining = len >> du_bits;
struct page *pages[16]; /* write up to 16 pages at a time */
unsigned int nr_pages;
unsigned int i;
unsigned int offset;
struct bio *bio;
int ret, err;
if (len == 0)
return 0;
if (fscrypt_inode_uses_inline_crypto(inode))
return fscrypt_zeroout_range_inline_crypt(inode, pos, sector,
len);
BUILD_BUG_ON(ARRAY_SIZE(pages) > BIO_MAX_VECS);
nr_pages = min_t(u64, ARRAY_SIZE(pages),
(du_remaining + du_per_page - 1) >> du_per_page_bits);
/*
* We need at least one page for ciphertext. Allocate the first one
* from a mempool, with __GFP_DIRECT_RECLAIM set so that it can't fail.
*
* Any additional page allocations are allowed to fail, as they only
* help performance, and waiting on the mempool for them could deadlock.
*/
for (i = 0; i < nr_pages; i++) {
pages[i] = fscrypt_alloc_bounce_page(i == 0 ? GFP_NOFS :
GFP_NOWAIT);
if (!pages[i])
break;
}
nr_pages = i;
if (WARN_ON_ONCE(nr_pages <= 0))
return -EINVAL;
/* This always succeeds since __GFP_DIRECT_RECLAIM is set. */
bio = bio_alloc(inode->i_sb->s_bdev, nr_pages, REQ_OP_WRITE, GFP_NOFS);
do {
bio->bi_iter.bi_sector = sector;
i = 0;
offset = 0;
do {
err = fscrypt_crypt_data_unit(ci, FS_ENCRYPT, du_index,
ZERO_PAGE(0), pages[i],
du_size, offset);
if (err)
goto out;
du_index++;
sector += 1U << (du_bits - SECTOR_SHIFT);
du_remaining--;
offset += du_size;
if (offset == PAGE_SIZE || du_remaining == 0) {
ret = bio_add_page(bio, pages[i++], offset, 0);
if (WARN_ON_ONCE(ret != offset)) {
err = -EIO;
goto out;
}
offset = 0;
}
} while (i != nr_pages && du_remaining != 0);
err = submit_bio_wait(bio);
if (err)
goto out;
bio_reset(bio, inode->i_sb->s_bdev, REQ_OP_WRITE);
} while (du_remaining != 0);
err = 0;
out:
bio_put(bio);
for (i = 0; i < nr_pages; i++)
fscrypt_free_bounce_page(pages[i]);
return err;
}
EXPORT_SYMBOL(fscrypt_zeroout_range);

14
fs/crypto/crypto.c
View File

@ -49,7 +49,7 @@ void fscrypt_enqueue_decrypt_work(struct work_struct *work)
}
EXPORT_SYMBOL(fscrypt_enqueue_decrypt_work);
struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags)
static struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags)
{
if (WARN_ON_ONCE(!fscrypt_bounce_page_pool)) {
/*
@ -65,8 +65,7 @@ struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags)
* fscrypt_free_bounce_page() - free a ciphertext bounce page
* @bounce_page: the bounce page to free, or NULL
*
* Free a bounce page that was allocated by fscrypt_encrypt_pagecache_blocks(),
* or by fscrypt_alloc_bounce_page() directly.
* Free a bounce page that was allocated by fscrypt_encrypt_pagecache_blocks().
*/
void fscrypt_free_bounce_page(struct page *bounce_page)
{
@ -107,10 +106,11 @@ void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index,
}
/* Encrypt or decrypt a single "data unit" of file contents. */
int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
fscrypt_direction_t rw, u64 index,
struct page *src_page, struct page *dest_page,
unsigned int len, unsigned int offs)
static int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
fscrypt_direction_t rw, u64 index,
struct page *src_page,
struct page *dest_page, unsigned int len,
unsigned int offs)
{
struct crypto_sync_skcipher *tfm = ci->ci_enc_key.tfm;
SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);

5
fs/crypto/fscrypt_private.h
View File

@ -329,11 +329,6 @@ typedef enum {
/* crypto.c */
extern struct kmem_cache *fscrypt_inode_info_cachep;
int fscrypt_initialize(struct super_block *sb);
int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
fscrypt_direction_t rw, u64 index,
struct page *src_page, struct page *dest_page,
unsigned int len, unsigned int offs);
struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags);
void __printf(3, 4) __cold
fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...);