/*
* Convenience function which takes care of allocating and
* deallocating the encryption context
*/
int f2fs_decrypt_one(struct inode *inode, struct page *page)
{
struct f2fs_crypto_ctx *ctx = f2fs_get_crypto_ctx(inode);
int ret;
if (!ctx)
return -ENOMEM;
ret = f2fs_decrypt(ctx, page);
f2fs_release_crypto_ctx(ctx);
return ret;
}
/**
* f2fs_encrypt() - Encrypts a page
* @inode: The inode for which the encryption should take place
* @plaintext_page: The page to encrypt. Must be locked.
*
* Allocates a ciphertext page and encrypts plaintext_page into it using the ctx
* encryption context.
*
* Called on the page write path. The caller must call
* f2fs_restore_control_page() on the returned ciphertext page to
* release the bounce buffer and the encryption context.
*
* Return: An allocated page with the encrypted content on success. Else, an
* error value or NULL.
*/
struct page *f2fs_encrypt(struct inode *inode,
struct page *plaintext_page)
{
struct f2fs_crypto_ctx *ctx;
struct page *ciphertext_page = NULL;
int err;
BUG_ON(!PageLocked(plaintext_page));
ctx = f2fs_get_crypto_ctx(inode);
if (IS_ERR(ctx))
return (struct page *)ctx;
/* The encryption operation will require a bounce page. */
ctx->flags &= ~F2FS_MASK_PAGE_POOL_FREE_ENCRYPT_FL;
ciphertext_page = mempool_alloc(f2fs_bounce_page_pool, GFP_NOFS);
if (ciphertext_page) {
ctx->flags |= F2FS_BOUNCE_PAGE_POOL_FREE_ENCRYPT_FL;
goto got_it;
}
ciphertext_page = alloc_page(GFP_NOFS);
if (!ciphertext_page) {
/*
* This is a potential bottleneck, but at least we'll have
* forward progress.
*/
ciphertext_page = mempool_alloc(f2fs_emergent_page_pool,
GFP_NOFS);
if (WARN_ON_ONCE(!ciphertext_page))
ciphertext_page = mempool_alloc(f2fs_emergent_page_pool,
GFP_NOFS | __GFP_NOFAIL);
ctx->flags |= F2FS_EMERGENT_PAGE_POOL_FREE_ENCRYPT_FL;
}
got_it:
ctx->flags |= F2FS_WRITE_PATH_FL;
ctx->w.bounce_page = ciphertext_page;
ctx->w.control_page = plaintext_page;
err = f2fs_page_crypto(ctx, inode, F2FS_ENCRYPT, plaintext_page->index,
plaintext_page, ciphertext_page);
if (err) {
f2fs_release_crypto_ctx(ctx);
return ERR_PTR(err);
}
SetPagePrivate(ciphertext_page);
set_page_private(ciphertext_page, (unsigned long)ctx);
lock_page(ciphertext_page);
return ciphertext_page;
}
/*
* This function was originally taken from fs/mpage.c, and customized for f2fs.
* Major change was from block_size == page_size in f2fs by default.
*/
static int f2fs_mpage_readpages(struct address_space *mapping,
struct list_head *pages, struct page *page,
unsigned nr_pages)
{
struct bio *bio = NULL;
unsigned page_idx;
sector_t last_block_in_bio = 0;
struct inode *inode = mapping->host;
const unsigned blkbits = inode->i_blkbits;
const unsigned blocksize = 1 << blkbits;
sector_t block_in_file;
sector_t last_block;
sector_t last_block_in_file;
sector_t block_nr;
struct block_device *bdev = inode->i_sb->s_bdev;
struct f2fs_map_blocks map;
map.m_pblk = 0;
map.m_lblk = 0;
map.m_len = 0;
map.m_flags = 0;
for (page_idx = 0; nr_pages; page_idx++, nr_pages--) {
prefetchw(&page->flags);
if (pages) {
page = list_entry(pages->prev, struct page, lru);
list_del(&page->lru);
if (add_to_page_cache_lru(page, mapping,
page->index, GFP_KERNEL))
goto next_page;
}
block_in_file = (sector_t)page->index;
last_block = block_in_file + nr_pages;
last_block_in_file = (i_size_read(inode) + blocksize - 1) >>
blkbits;
if (last_block > last_block_in_file)
last_block = last_block_in_file;
/*
* Map blocks using the previous result first.
*/
if ((map.m_flags & F2FS_MAP_MAPPED) &&
block_in_file > map.m_lblk &&
block_in_file < (map.m_lblk + map.m_len))
goto got_it;
/*
* Then do more f2fs_map_blocks() calls until we are
* done with this page.
*/
map.m_flags = 0;
if (block_in_file < last_block) {
map.m_lblk = block_in_file;
map.m_len = last_block - block_in_file;
if (f2fs_map_blocks(inode, &map, 0, false))
goto set_error_page;
}
got_it:
if ((map.m_flags & F2FS_MAP_MAPPED)) {
block_nr = map.m_pblk + block_in_file - map.m_lblk;
SetPageMappedToDisk(page);
if (!PageUptodate(page) && !cleancache_get_page(page)) {
SetPageUptodate(page);
goto confused;
}
} else {
zero_user_segment(page, 0, PAGE_CACHE_SIZE);
SetPageUptodate(page);
unlock_page(page);
goto next_page;
}
/*
* This page will go to BIO. Do we need to send this
* BIO off first?
*/
if (bio && (last_block_in_bio != block_nr - 1)) {
submit_and_realloc:
submit_bio(READ, bio);
bio = NULL;
}
if (bio == NULL) {
struct f2fs_crypto_ctx *ctx = NULL;
if (f2fs_encrypted_inode(inode) &&
S_ISREG(inode->i_mode)) {
struct page *cpage;
ctx = f2fs_get_crypto_ctx(inode);
if (IS_ERR(ctx))
goto set_error_page;
/* wait the page to be moved by cleaning */
cpage = find_lock_page(
META_MAPPING(F2FS_I_SB(inode)),
block_nr);
if (cpage) {
f2fs_wait_on_page_writeback(cpage,
DATA);
f2fs_put_page(cpage, 1);
}
}
bio = bio_alloc(GFP_KERNEL,
min_t(int, nr_pages, BIO_MAX_PAGES));
if (!bio) {
if (ctx)
f2fs_release_crypto_ctx(ctx);
goto set_error_page;
}
bio->bi_bdev = bdev;
bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(block_nr);
bio->bi_end_io = f2fs_read_end_io;
bio->bi_private = ctx;
}
if (bio_add_page(bio, page, blocksize, 0) < blocksize)
goto submit_and_realloc;
last_block_in_bio = block_nr;
goto next_page;
set_error_page:
SetPageError(page);
zero_user_segment(page, 0, PAGE_CACHE_SIZE);
unlock_page(page);
goto next_page;
confused:
if (bio) {
submit_bio(READ, bio);
bio = NULL;
}
unlock_page(page);
next_page:
if (pages)
page_cache_release(page);
}
BUG_ON(pages && !list_empty(pages));
if (bio)
submit_bio(READ, bio);
return 0;
}