15fee3609SSatya Tangirala // SPDX-License-Identifier: GPL-2.0 25fee3609SSatya Tangirala /* 35fee3609SSatya Tangirala * Inline encryption support for fscrypt 45fee3609SSatya Tangirala * 55fee3609SSatya Tangirala * Copyright 2019 Google LLC 65fee3609SSatya Tangirala */ 75fee3609SSatya Tangirala 85fee3609SSatya Tangirala /* 95fee3609SSatya Tangirala * With "inline encryption", the block layer handles the decryption/encryption 105fee3609SSatya Tangirala * as part of the bio, instead of the filesystem doing the crypto itself via 115fee3609SSatya Tangirala * crypto API. See Documentation/block/inline-encryption.rst. fscrypt still 125fee3609SSatya Tangirala * provides the key and IV to use. 135fee3609SSatya Tangirala */ 145fee3609SSatya Tangirala 155fee3609SSatya Tangirala #include <linux/blk-crypto.h> 165fee3609SSatya Tangirala #include <linux/blkdev.h> 175fee3609SSatya Tangirala #include <linux/buffer_head.h> 185fee3609SSatya Tangirala #include <linux/sched/mm.h> 19453431a5SWaiman Long #include <linux/slab.h> 205fee3609SSatya Tangirala 215fee3609SSatya Tangirala #include "fscrypt_private.h" 225fee3609SSatya Tangirala 235fee3609SSatya Tangirala struct fscrypt_blk_crypto_key { 245fee3609SSatya Tangirala struct blk_crypto_key base; 255fee3609SSatya Tangirala int num_devs; 265fee3609SSatya Tangirala struct request_queue *devs[]; 275fee3609SSatya Tangirala }; 285fee3609SSatya Tangirala 295fee3609SSatya Tangirala static int fscrypt_get_num_devices(struct super_block *sb) 305fee3609SSatya Tangirala { 315fee3609SSatya Tangirala if (sb->s_cop->get_num_devices) 325fee3609SSatya Tangirala return sb->s_cop->get_num_devices(sb); 335fee3609SSatya Tangirala return 1; 345fee3609SSatya Tangirala } 355fee3609SSatya Tangirala 365fee3609SSatya Tangirala static void fscrypt_get_devices(struct super_block *sb, int num_devs, 375fee3609SSatya Tangirala struct request_queue **devs) 385fee3609SSatya Tangirala { 395fee3609SSatya Tangirala if (num_devs == 1) 405fee3609SSatya Tangirala devs[0] = bdev_get_queue(sb->s_bdev); 415fee3609SSatya Tangirala else 425fee3609SSatya Tangirala sb->s_cop->get_devices(sb, devs); 435fee3609SSatya Tangirala } 445fee3609SSatya Tangirala 455fee3609SSatya Tangirala static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci) 465fee3609SSatya Tangirala { 475fee3609SSatya Tangirala struct super_block *sb = ci->ci_inode->i_sb; 485fee3609SSatya Tangirala unsigned int flags = fscrypt_policy_flags(&ci->ci_policy); 495fee3609SSatya Tangirala int ino_bits = 64, lblk_bits = 64; 505fee3609SSatya Tangirala 515fee3609SSatya Tangirala if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) 525fee3609SSatya Tangirala return offsetofend(union fscrypt_iv, nonce); 535fee3609SSatya Tangirala 545fee3609SSatya Tangirala if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) 555fee3609SSatya Tangirala return sizeof(__le64); 565fee3609SSatya Tangirala 575fee3609SSatya Tangirala if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) 585fee3609SSatya Tangirala return sizeof(__le32); 595fee3609SSatya Tangirala 605fee3609SSatya Tangirala /* Default case: IVs are just the file logical block number */ 615fee3609SSatya Tangirala if (sb->s_cop->get_ino_and_lblk_bits) 625fee3609SSatya Tangirala sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits); 635fee3609SSatya Tangirala return DIV_ROUND_UP(lblk_bits, 8); 645fee3609SSatya Tangirala } 655fee3609SSatya Tangirala 665fee3609SSatya Tangirala /* Enable inline encryption for this file if supported. */ 675fee3609SSatya Tangirala int fscrypt_select_encryption_impl(struct fscrypt_info *ci) 685fee3609SSatya Tangirala { 695fee3609SSatya Tangirala const struct inode *inode = ci->ci_inode; 705fee3609SSatya Tangirala struct super_block *sb = inode->i_sb; 715fee3609SSatya Tangirala struct blk_crypto_config crypto_cfg; 725fee3609SSatya Tangirala int num_devs; 735fee3609SSatya Tangirala struct request_queue **devs; 745fee3609SSatya Tangirala int i; 755fee3609SSatya Tangirala 765fee3609SSatya Tangirala /* The file must need contents encryption, not filenames encryption */ 77d19d8d34SEric Biggers if (!S_ISREG(inode->i_mode)) 785fee3609SSatya Tangirala return 0; 795fee3609SSatya Tangirala 805fee3609SSatya Tangirala /* The crypto mode must have a blk-crypto counterpart */ 815fee3609SSatya Tangirala if (ci->ci_mode->blk_crypto_mode == BLK_ENCRYPTION_MODE_INVALID) 825fee3609SSatya Tangirala return 0; 835fee3609SSatya Tangirala 845fee3609SSatya Tangirala /* The filesystem must be mounted with -o inlinecrypt */ 855fee3609SSatya Tangirala if (!(sb->s_flags & SB_INLINECRYPT)) 865fee3609SSatya Tangirala return 0; 875fee3609SSatya Tangirala 885fee3609SSatya Tangirala /* 895fee3609SSatya Tangirala * When a page contains multiple logically contiguous filesystem blocks, 905fee3609SSatya Tangirala * some filesystem code only calls fscrypt_mergeable_bio() for the first 915fee3609SSatya Tangirala * block in the page. This is fine for most of fscrypt's IV generation 925fee3609SSatya Tangirala * strategies, where contiguous blocks imply contiguous IVs. But it 935fee3609SSatya Tangirala * doesn't work with IV_INO_LBLK_32. For now, simply exclude 945fee3609SSatya Tangirala * IV_INO_LBLK_32 with blocksize != PAGE_SIZE from inline encryption. 955fee3609SSatya Tangirala */ 965fee3609SSatya Tangirala if ((fscrypt_policy_flags(&ci->ci_policy) & 975fee3609SSatya Tangirala FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) && 985fee3609SSatya Tangirala sb->s_blocksize != PAGE_SIZE) 995fee3609SSatya Tangirala return 0; 1005fee3609SSatya Tangirala 1015fee3609SSatya Tangirala /* 1025fee3609SSatya Tangirala * On all the filesystem's devices, blk-crypto must support the crypto 1035fee3609SSatya Tangirala * configuration that the file would use. 1045fee3609SSatya Tangirala */ 1055fee3609SSatya Tangirala crypto_cfg.crypto_mode = ci->ci_mode->blk_crypto_mode; 1065fee3609SSatya Tangirala crypto_cfg.data_unit_size = sb->s_blocksize; 1075fee3609SSatya Tangirala crypto_cfg.dun_bytes = fscrypt_get_dun_bytes(ci); 1085fee3609SSatya Tangirala num_devs = fscrypt_get_num_devices(sb); 1099dad5febSEric Biggers devs = kmalloc_array(num_devs, sizeof(*devs), GFP_KERNEL); 1105fee3609SSatya Tangirala if (!devs) 1115fee3609SSatya Tangirala return -ENOMEM; 1125fee3609SSatya Tangirala fscrypt_get_devices(sb, num_devs, devs); 1135fee3609SSatya Tangirala 1145fee3609SSatya Tangirala for (i = 0; i < num_devs; i++) { 1155fee3609SSatya Tangirala if (!blk_crypto_config_supported(devs[i], &crypto_cfg)) 1165fee3609SSatya Tangirala goto out_free_devs; 1175fee3609SSatya Tangirala } 1185fee3609SSatya Tangirala 1195fee3609SSatya Tangirala ci->ci_inlinecrypt = true; 1205fee3609SSatya Tangirala out_free_devs: 1215fee3609SSatya Tangirala kfree(devs); 1225fee3609SSatya Tangirala 1235fee3609SSatya Tangirala return 0; 1245fee3609SSatya Tangirala } 1255fee3609SSatya Tangirala 1265fee3609SSatya Tangirala int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, 1275fee3609SSatya Tangirala const u8 *raw_key, 1285fee3609SSatya Tangirala const struct fscrypt_info *ci) 1295fee3609SSatya Tangirala { 1305fee3609SSatya Tangirala const struct inode *inode = ci->ci_inode; 1315fee3609SSatya Tangirala struct super_block *sb = inode->i_sb; 1325fee3609SSatya Tangirala enum blk_crypto_mode_num crypto_mode = ci->ci_mode->blk_crypto_mode; 1335fee3609SSatya Tangirala int num_devs = fscrypt_get_num_devices(sb); 1345fee3609SSatya Tangirala int queue_refs = 0; 1355fee3609SSatya Tangirala struct fscrypt_blk_crypto_key *blk_key; 1365fee3609SSatya Tangirala int err; 1375fee3609SSatya Tangirala int i; 1385fee3609SSatya Tangirala 1399dad5febSEric Biggers blk_key = kzalloc(struct_size(blk_key, devs, num_devs), GFP_KERNEL); 1405fee3609SSatya Tangirala if (!blk_key) 1415fee3609SSatya Tangirala return -ENOMEM; 1425fee3609SSatya Tangirala 1435fee3609SSatya Tangirala blk_key->num_devs = num_devs; 1445fee3609SSatya Tangirala fscrypt_get_devices(sb, num_devs, blk_key->devs); 1455fee3609SSatya Tangirala 1465fee3609SSatya Tangirala err = blk_crypto_init_key(&blk_key->base, raw_key, crypto_mode, 1475fee3609SSatya Tangirala fscrypt_get_dun_bytes(ci), sb->s_blocksize); 1485fee3609SSatya Tangirala if (err) { 1495fee3609SSatya Tangirala fscrypt_err(inode, "error %d initializing blk-crypto key", err); 1505fee3609SSatya Tangirala goto fail; 1515fee3609SSatya Tangirala } 1525fee3609SSatya Tangirala 1535fee3609SSatya Tangirala /* 1545fee3609SSatya Tangirala * We have to start using blk-crypto on all the filesystem's devices. 1555fee3609SSatya Tangirala * We also have to save all the request_queue's for later so that the 1565fee3609SSatya Tangirala * key can be evicted from them. This is needed because some keys 1575fee3609SSatya Tangirala * aren't destroyed until after the filesystem was already unmounted 1585fee3609SSatya Tangirala * (namely, the per-mode keys in struct fscrypt_master_key). 1595fee3609SSatya Tangirala */ 1605fee3609SSatya Tangirala for (i = 0; i < num_devs; i++) { 1615fee3609SSatya Tangirala if (!blk_get_queue(blk_key->devs[i])) { 1625fee3609SSatya Tangirala fscrypt_err(inode, "couldn't get request_queue"); 1635fee3609SSatya Tangirala err = -EAGAIN; 1645fee3609SSatya Tangirala goto fail; 1655fee3609SSatya Tangirala } 1665fee3609SSatya Tangirala queue_refs++; 1675fee3609SSatya Tangirala 1685fee3609SSatya Tangirala err = blk_crypto_start_using_key(&blk_key->base, 1695fee3609SSatya Tangirala blk_key->devs[i]); 1705fee3609SSatya Tangirala if (err) { 1715fee3609SSatya Tangirala fscrypt_err(inode, 1725fee3609SSatya Tangirala "error %d starting to use blk-crypto", err); 1735fee3609SSatya Tangirala goto fail; 1745fee3609SSatya Tangirala } 1755fee3609SSatya Tangirala } 1765fee3609SSatya Tangirala /* 17797c6327fSEric Biggers * Pairs with the smp_load_acquire() in fscrypt_is_key_prepared(). 17897c6327fSEric Biggers * I.e., here we publish ->blk_key with a RELEASE barrier so that 17997c6327fSEric Biggers * concurrent tasks can ACQUIRE it. Note that this concurrency is only 18097c6327fSEric Biggers * possible for per-mode keys, not for per-file keys. 1815fee3609SSatya Tangirala */ 1825fee3609SSatya Tangirala smp_store_release(&prep_key->blk_key, blk_key); 1835fee3609SSatya Tangirala return 0; 1845fee3609SSatya Tangirala 1855fee3609SSatya Tangirala fail: 1865fee3609SSatya Tangirala for (i = 0; i < queue_refs; i++) 1875fee3609SSatya Tangirala blk_put_queue(blk_key->devs[i]); 188453431a5SWaiman Long kfree_sensitive(blk_key); 1895fee3609SSatya Tangirala return err; 1905fee3609SSatya Tangirala } 1915fee3609SSatya Tangirala 1925fee3609SSatya Tangirala void fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key *prep_key) 1935fee3609SSatya Tangirala { 1945fee3609SSatya Tangirala struct fscrypt_blk_crypto_key *blk_key = prep_key->blk_key; 1955fee3609SSatya Tangirala int i; 1965fee3609SSatya Tangirala 1975fee3609SSatya Tangirala if (blk_key) { 1985fee3609SSatya Tangirala for (i = 0; i < blk_key->num_devs; i++) { 1995fee3609SSatya Tangirala blk_crypto_evict_key(blk_key->devs[i], &blk_key->base); 2005fee3609SSatya Tangirala blk_put_queue(blk_key->devs[i]); 2015fee3609SSatya Tangirala } 202453431a5SWaiman Long kfree_sensitive(blk_key); 2035fee3609SSatya Tangirala } 2045fee3609SSatya Tangirala } 2055fee3609SSatya Tangirala 2065fee3609SSatya Tangirala bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode) 2075fee3609SSatya Tangirala { 2085fee3609SSatya Tangirala return inode->i_crypt_info->ci_inlinecrypt; 2095fee3609SSatya Tangirala } 2105fee3609SSatya Tangirala EXPORT_SYMBOL_GPL(__fscrypt_inode_uses_inline_crypto); 2115fee3609SSatya Tangirala 2125fee3609SSatya Tangirala static void fscrypt_generate_dun(const struct fscrypt_info *ci, u64 lblk_num, 2135fee3609SSatya Tangirala u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE]) 2145fee3609SSatya Tangirala { 2155fee3609SSatya Tangirala union fscrypt_iv iv; 2165fee3609SSatya Tangirala int i; 2175fee3609SSatya Tangirala 2185fee3609SSatya Tangirala fscrypt_generate_iv(&iv, lblk_num, ci); 2195fee3609SSatya Tangirala 2205fee3609SSatya Tangirala BUILD_BUG_ON(FSCRYPT_MAX_IV_SIZE > BLK_CRYPTO_MAX_IV_SIZE); 2215fee3609SSatya Tangirala memset(dun, 0, BLK_CRYPTO_MAX_IV_SIZE); 2225fee3609SSatya Tangirala for (i = 0; i < ci->ci_mode->ivsize/sizeof(dun[0]); i++) 2235fee3609SSatya Tangirala dun[i] = le64_to_cpu(iv.dun[i]); 2245fee3609SSatya Tangirala } 2255fee3609SSatya Tangirala 2265fee3609SSatya Tangirala /** 2275fee3609SSatya Tangirala * fscrypt_set_bio_crypt_ctx() - prepare a file contents bio for inline crypto 2285fee3609SSatya Tangirala * @bio: a bio which will eventually be submitted to the file 2295fee3609SSatya Tangirala * @inode: the file's inode 2305fee3609SSatya Tangirala * @first_lblk: the first file logical block number in the I/O 2315fee3609SSatya Tangirala * @gfp_mask: memory allocation flags - these must be a waiting mask so that 2325fee3609SSatya Tangirala * bio_crypt_set_ctx can't fail. 2335fee3609SSatya Tangirala * 2345fee3609SSatya Tangirala * If the contents of the file should be encrypted (or decrypted) with inline 2355fee3609SSatya Tangirala * encryption, then assign the appropriate encryption context to the bio. 2365fee3609SSatya Tangirala * 2375fee3609SSatya Tangirala * Normally the bio should be newly allocated (i.e. no pages added yet), as 2385fee3609SSatya Tangirala * otherwise fscrypt_mergeable_bio() won't work as intended. 2395fee3609SSatya Tangirala * 2405fee3609SSatya Tangirala * The encryption context will be freed automatically when the bio is freed. 2415fee3609SSatya Tangirala */ 2425fee3609SSatya Tangirala void fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode, 2435fee3609SSatya Tangirala u64 first_lblk, gfp_t gfp_mask) 2445fee3609SSatya Tangirala { 24555e32c54SEric Biggers const struct fscrypt_info *ci; 2465fee3609SSatya Tangirala u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE]; 2475fee3609SSatya Tangirala 2485fee3609SSatya Tangirala if (!fscrypt_inode_uses_inline_crypto(inode)) 2495fee3609SSatya Tangirala return; 25055e32c54SEric Biggers ci = inode->i_crypt_info; 2515fee3609SSatya Tangirala 2525fee3609SSatya Tangirala fscrypt_generate_dun(ci, first_lblk, dun); 2535fee3609SSatya Tangirala bio_crypt_set_ctx(bio, &ci->ci_enc_key.blk_key->base, dun, gfp_mask); 2545fee3609SSatya Tangirala } 2555fee3609SSatya Tangirala EXPORT_SYMBOL_GPL(fscrypt_set_bio_crypt_ctx); 2565fee3609SSatya Tangirala 2575fee3609SSatya Tangirala /* Extract the inode and logical block number from a buffer_head. */ 2585fee3609SSatya Tangirala static bool bh_get_inode_and_lblk_num(const struct buffer_head *bh, 2595fee3609SSatya Tangirala const struct inode **inode_ret, 2605fee3609SSatya Tangirala u64 *lblk_num_ret) 2615fee3609SSatya Tangirala { 2625fee3609SSatya Tangirala struct page *page = bh->b_page; 2635fee3609SSatya Tangirala const struct address_space *mapping; 2645fee3609SSatya Tangirala const struct inode *inode; 2655fee3609SSatya Tangirala 2665fee3609SSatya Tangirala /* 2675fee3609SSatya Tangirala * The ext4 journal (jbd2) can submit a buffer_head it directly created 2685fee3609SSatya Tangirala * for a non-pagecache page. fscrypt doesn't care about these. 2695fee3609SSatya Tangirala */ 2705fee3609SSatya Tangirala mapping = page_mapping(page); 2715fee3609SSatya Tangirala if (!mapping) 2725fee3609SSatya Tangirala return false; 2735fee3609SSatya Tangirala inode = mapping->host; 2745fee3609SSatya Tangirala 2755fee3609SSatya Tangirala *inode_ret = inode; 2765fee3609SSatya Tangirala *lblk_num_ret = ((u64)page->index << (PAGE_SHIFT - inode->i_blkbits)) + 2775fee3609SSatya Tangirala (bh_offset(bh) >> inode->i_blkbits); 2785fee3609SSatya Tangirala return true; 2795fee3609SSatya Tangirala } 2805fee3609SSatya Tangirala 2815fee3609SSatya Tangirala /** 2825fee3609SSatya Tangirala * fscrypt_set_bio_crypt_ctx_bh() - prepare a file contents bio for inline 2835fee3609SSatya Tangirala * crypto 2845fee3609SSatya Tangirala * @bio: a bio which will eventually be submitted to the file 2855fee3609SSatya Tangirala * @first_bh: the first buffer_head for which I/O will be submitted 2865fee3609SSatya Tangirala * @gfp_mask: memory allocation flags 2875fee3609SSatya Tangirala * 2885fee3609SSatya Tangirala * Same as fscrypt_set_bio_crypt_ctx(), except this takes a buffer_head instead 2895fee3609SSatya Tangirala * of an inode and block number directly. 2905fee3609SSatya Tangirala */ 2915fee3609SSatya Tangirala void fscrypt_set_bio_crypt_ctx_bh(struct bio *bio, 2925fee3609SSatya Tangirala const struct buffer_head *first_bh, 2935fee3609SSatya Tangirala gfp_t gfp_mask) 2945fee3609SSatya Tangirala { 2955fee3609SSatya Tangirala const struct inode *inode; 2965fee3609SSatya Tangirala u64 first_lblk; 2975fee3609SSatya Tangirala 2985fee3609SSatya Tangirala if (bh_get_inode_and_lblk_num(first_bh, &inode, &first_lblk)) 2995fee3609SSatya Tangirala fscrypt_set_bio_crypt_ctx(bio, inode, first_lblk, gfp_mask); 3005fee3609SSatya Tangirala } 3015fee3609SSatya Tangirala EXPORT_SYMBOL_GPL(fscrypt_set_bio_crypt_ctx_bh); 3025fee3609SSatya Tangirala 3035fee3609SSatya Tangirala /** 3045fee3609SSatya Tangirala * fscrypt_mergeable_bio() - test whether data can be added to a bio 3055fee3609SSatya Tangirala * @bio: the bio being built up 3065fee3609SSatya Tangirala * @inode: the inode for the next part of the I/O 3075fee3609SSatya Tangirala * @next_lblk: the next file logical block number in the I/O 3085fee3609SSatya Tangirala * 3095fee3609SSatya Tangirala * When building a bio which may contain data which should undergo inline 3105fee3609SSatya Tangirala * encryption (or decryption) via fscrypt, filesystems should call this function 3115fee3609SSatya Tangirala * to ensure that the resulting bio contains only contiguous data unit numbers. 3125fee3609SSatya Tangirala * This will return false if the next part of the I/O cannot be merged with the 3135fee3609SSatya Tangirala * bio because either the encryption key would be different or the encryption 3145fee3609SSatya Tangirala * data unit numbers would be discontiguous. 3155fee3609SSatya Tangirala * 3165fee3609SSatya Tangirala * fscrypt_set_bio_crypt_ctx() must have already been called on the bio. 3175fee3609SSatya Tangirala * 3185fee3609SSatya Tangirala * Return: true iff the I/O is mergeable 3195fee3609SSatya Tangirala */ 3205fee3609SSatya Tangirala bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode, 3215fee3609SSatya Tangirala u64 next_lblk) 3225fee3609SSatya Tangirala { 3235fee3609SSatya Tangirala const struct bio_crypt_ctx *bc = bio->bi_crypt_context; 3245fee3609SSatya Tangirala u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE]; 3255fee3609SSatya Tangirala 3265fee3609SSatya Tangirala if (!!bc != fscrypt_inode_uses_inline_crypto(inode)) 3275fee3609SSatya Tangirala return false; 3285fee3609SSatya Tangirala if (!bc) 3295fee3609SSatya Tangirala return true; 3305fee3609SSatya Tangirala 3315fee3609SSatya Tangirala /* 3325fee3609SSatya Tangirala * Comparing the key pointers is good enough, as all I/O for each key 3335fee3609SSatya Tangirala * uses the same pointer. I.e., there's currently no need to support 3345fee3609SSatya Tangirala * merging requests where the keys are the same but the pointers differ. 3355fee3609SSatya Tangirala */ 3365fee3609SSatya Tangirala if (bc->bc_key != &inode->i_crypt_info->ci_enc_key.blk_key->base) 3375fee3609SSatya Tangirala return false; 3385fee3609SSatya Tangirala 3395fee3609SSatya Tangirala fscrypt_generate_dun(inode->i_crypt_info, next_lblk, next_dun); 3405fee3609SSatya Tangirala return bio_crypt_dun_is_contiguous(bc, bio->bi_iter.bi_size, next_dun); 3415fee3609SSatya Tangirala } 3425fee3609SSatya Tangirala EXPORT_SYMBOL_GPL(fscrypt_mergeable_bio); 3435fee3609SSatya Tangirala 3445fee3609SSatya Tangirala /** 3455fee3609SSatya Tangirala * fscrypt_mergeable_bio_bh() - test whether data can be added to a bio 3465fee3609SSatya Tangirala * @bio: the bio being built up 3475fee3609SSatya Tangirala * @next_bh: the next buffer_head for which I/O will be submitted 3485fee3609SSatya Tangirala * 3495fee3609SSatya Tangirala * Same as fscrypt_mergeable_bio(), except this takes a buffer_head instead of 3505fee3609SSatya Tangirala * an inode and block number directly. 3515fee3609SSatya Tangirala * 3525fee3609SSatya Tangirala * Return: true iff the I/O is mergeable 3535fee3609SSatya Tangirala */ 3545fee3609SSatya Tangirala bool fscrypt_mergeable_bio_bh(struct bio *bio, 3555fee3609SSatya Tangirala const struct buffer_head *next_bh) 3565fee3609SSatya Tangirala { 3575fee3609SSatya Tangirala const struct inode *inode; 3585fee3609SSatya Tangirala u64 next_lblk; 3595fee3609SSatya Tangirala 3605fee3609SSatya Tangirala if (!bh_get_inode_and_lblk_num(next_bh, &inode, &next_lblk)) 3615fee3609SSatya Tangirala return !bio->bi_crypt_context; 3625fee3609SSatya Tangirala 3635fee3609SSatya Tangirala return fscrypt_mergeable_bio(bio, inode, next_lblk); 3645fee3609SSatya Tangirala } 3655fee3609SSatya Tangirala EXPORT_SYMBOL_GPL(fscrypt_mergeable_bio_bh); 366