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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Linus Torvalds](/assets/img/avatar_default.png)
whether blocks should migrate to/from the cache. The bio-prison-v2 interface supports this improvement by enabling direct dispatch of work to workqueues rather than having to delay the actual work dispatch to the DM cache core. So the dm-cache policies are much more nimble by being able to drive IO as they see fit. One immediate benefit from the improved latency is a cache that should be much more adaptive to changing workloads. - Add a new DM integrity target that emulates a block device that has additional per-sector tags that can be used for storing integrity information. - Add a new authenticated encryption feature to the DM crypt target that builds on the capabilities provided by the DM integrity target. - Add MD interface for switching the raid4/5/6 journal mode and update the DM raid target to use it to enable aid4/5/6 journal write-back support. - Switch the DM verity target over to using the asynchronous hash crypto API (this helps work better with architectures that have access to off-CPU algorithm providers, which should reduce CPU utilization). - Various request-based DM and DM multipath fixes and improvements from Bart and Christoph. - A DM thinp target fix for a bio structure leak that occurs for each discard IFF discard passdown is enabled. - A fix for a possible deadlock in DM bufio and a fix to re-check the new buffer allocation watermark in the face of competing admin changes to the 'max_cache_size_bytes' tunable. - A couple DM core cleanups. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAABAgAGBQJZB6vtAAoJEMUj8QotnQNaoicIALuZTLElgAzxzA28cfk1+1Ea Gd09CfJ3M6cvk/YGUU7WwiSYIwu16yOJALG4sLcYnEmUCzvKfFPcl/RpeSJHPpYM 0aVXa6NIJw7K2r3C17toiK2DRMHYw6QU843WeWI93vBW13lDJklNJL9fM7GBEOLH NMSNw2mAq9ajtLlnJhM3ZfhloA7/u/jektvlBO1AA3RQ5Kx1cXVXFPqN7FdRfcqp 4RuEMe9faAadlXLsj3bia5IBmF/W0Qza6JilP+NLKLWB4fm7LZDjN/k+TsHWMa9e cGR73TgUGLMBJX+sDJy8R3oeBG9JZkFVkD7I30eCjzyhSOs/54XNYQ23EkqHJU0= =9Ryi -----END PGP SIGNATURE----- Merge tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper updates from Mike Snitzer: - A major update for DM cache that reduces the latency for deciding whether blocks should migrate to/from the cache. The bio-prison-v2 interface supports this improvement by enabling direct dispatch of work to workqueues rather than having to delay the actual work dispatch to the DM cache core. So the dm-cache policies are much more nimble by being able to drive IO as they see fit. One immediate benefit from the improved latency is a cache that should be much more adaptive to changing workloads. - Add a new DM integrity target that emulates a block device that has additional per-sector tags that can be used for storing integrity information. - Add a new authenticated encryption feature to the DM crypt target that builds on the capabilities provided by the DM integrity target. - Add MD interface for switching the raid4/5/6 journal mode and update the DM raid target to use it to enable aid4/5/6 journal write-back support. - Switch the DM verity target over to using the asynchronous hash crypto API (this helps work better with architectures that have access to off-CPU algorithm providers, which should reduce CPU utilization). - Various request-based DM and DM multipath fixes and improvements from Bart and Christoph. - A DM thinp target fix for a bio structure leak that occurs for each discard IFF discard passdown is enabled. - A fix for a possible deadlock in DM bufio and a fix to re-check the new buffer allocation watermark in the face of competing admin changes to the 'max_cache_size_bytes' tunable. - A couple DM core cleanups. * tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (50 commits) dm bufio: check new buffer allocation watermark every 30 seconds dm bufio: avoid a possible ABBA deadlock dm mpath: make it easier to detect unintended I/O request flushes dm mpath: cleanup QUEUE_IF_NO_PATH bit manipulation by introducing assign_bit() dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH dm: introduce enum dm_queue_mode to cleanup related code dm mpath: verify __pg_init_all_paths locking assumptions at runtime dm: verify suspend_locking assumptions at runtime dm block manager: remove an unused argument from dm_block_manager_create() dm rq: check blk_mq_register_dev() return value in dm_mq_init_request_queue() dm mpath: delay requeuing while path initialization is in progress dm mpath: avoid that path removal can trigger an infinite loop dm mpath: split and rename activate_path() to prepare for its expanded use dm ioctl: prevent stack leak in dm ioctl call dm integrity: use previously calculated log2 of sectors_per_block dm integrity: use hex2bin instead of open-coded variant dm crypt: replace custom implementation of hex2bin() dm crypt: remove obsolete references to per-CPU state dm verity: switch to using asynchronous hash crypto API dm crypt: use WQ_HIGHPRI for the IO and crypt workqueues ...
826 lines
21 KiB
C
826 lines
21 KiB
C
/*
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* Copyright (C) 2015 Google, Inc.
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*
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* Author: Sami Tolvanen <samitolvanen@google.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*/
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#include "dm-verity-fec.h"
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#include <linux/math64.h>
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#define DM_MSG_PREFIX "verity-fec"
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/*
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* If error correction has been configured, returns true.
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*/
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bool verity_fec_is_enabled(struct dm_verity *v)
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{
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return v->fec && v->fec->dev;
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}
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/*
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* Return a pointer to dm_verity_fec_io after dm_verity_io and its variable
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* length fields.
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*/
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static inline struct dm_verity_fec_io *fec_io(struct dm_verity_io *io)
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{
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return (struct dm_verity_fec_io *) verity_io_digest_end(io->v, io);
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}
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/*
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* Return an interleaved offset for a byte in RS block.
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*/
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static inline u64 fec_interleave(struct dm_verity *v, u64 offset)
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{
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u32 mod;
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mod = do_div(offset, v->fec->rsn);
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return offset + mod * (v->fec->rounds << v->data_dev_block_bits);
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}
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/*
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* Decode an RS block using Reed-Solomon.
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*/
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static int fec_decode_rs8(struct dm_verity *v, struct dm_verity_fec_io *fio,
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u8 *data, u8 *fec, int neras)
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{
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int i;
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uint16_t par[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN];
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for (i = 0; i < v->fec->roots; i++)
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par[i] = fec[i];
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return decode_rs8(fio->rs, data, par, v->fec->rsn, NULL, neras,
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fio->erasures, 0, NULL);
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}
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/*
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* Read error-correcting codes for the requested RS block. Returns a pointer
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* to the data block. Caller is responsible for releasing buf.
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*/
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static u8 *fec_read_parity(struct dm_verity *v, u64 rsb, int index,
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unsigned *offset, struct dm_buffer **buf)
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{
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u64 position, block;
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u8 *res;
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position = (index + rsb) * v->fec->roots;
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block = position >> v->data_dev_block_bits;
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*offset = (unsigned)(position - (block << v->data_dev_block_bits));
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res = dm_bufio_read(v->fec->bufio, v->fec->start + block, buf);
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if (unlikely(IS_ERR(res))) {
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DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",
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v->data_dev->name, (unsigned long long)rsb,
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(unsigned long long)(v->fec->start + block),
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PTR_ERR(res));
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*buf = NULL;
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}
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return res;
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}
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/* Loop over each preallocated buffer slot. */
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#define fec_for_each_prealloc_buffer(__i) \
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for (__i = 0; __i < DM_VERITY_FEC_BUF_PREALLOC; __i++)
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/* Loop over each extra buffer slot. */
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#define fec_for_each_extra_buffer(io, __i) \
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for (__i = DM_VERITY_FEC_BUF_PREALLOC; __i < DM_VERITY_FEC_BUF_MAX; __i++)
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/* Loop over each allocated buffer. */
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#define fec_for_each_buffer(io, __i) \
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for (__i = 0; __i < (io)->nbufs; __i++)
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/* Loop over each RS block in each allocated buffer. */
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#define fec_for_each_buffer_rs_block(io, __i, __j) \
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fec_for_each_buffer(io, __i) \
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for (__j = 0; __j < 1 << DM_VERITY_FEC_BUF_RS_BITS; __j++)
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/*
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* Return a pointer to the current RS block when called inside
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* fec_for_each_buffer_rs_block.
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*/
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static inline u8 *fec_buffer_rs_block(struct dm_verity *v,
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struct dm_verity_fec_io *fio,
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unsigned i, unsigned j)
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{
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return &fio->bufs[i][j * v->fec->rsn];
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}
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/*
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* Return an index to the current RS block when called inside
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* fec_for_each_buffer_rs_block.
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*/
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static inline unsigned fec_buffer_rs_index(unsigned i, unsigned j)
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{
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return (i << DM_VERITY_FEC_BUF_RS_BITS) + j;
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}
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/*
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* Decode all RS blocks from buffers and copy corrected bytes into fio->output
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* starting from block_offset.
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*/
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static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio,
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u64 rsb, int byte_index, unsigned block_offset,
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int neras)
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{
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int r, corrected = 0, res;
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struct dm_buffer *buf;
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unsigned n, i, offset;
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u8 *par, *block;
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par = fec_read_parity(v, rsb, block_offset, &offset, &buf);
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if (IS_ERR(par))
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return PTR_ERR(par);
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/*
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* Decode the RS blocks we have in bufs. Each RS block results in
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* one corrected target byte and consumes fec->roots parity bytes.
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*/
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fec_for_each_buffer_rs_block(fio, n, i) {
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block = fec_buffer_rs_block(v, fio, n, i);
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res = fec_decode_rs8(v, fio, block, &par[offset], neras);
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if (res < 0) {
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r = res;
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goto error;
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}
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corrected += res;
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fio->output[block_offset] = block[byte_index];
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block_offset++;
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if (block_offset >= 1 << v->data_dev_block_bits)
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goto done;
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/* read the next block when we run out of parity bytes */
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offset += v->fec->roots;
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if (offset >= 1 << v->data_dev_block_bits) {
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dm_bufio_release(buf);
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par = fec_read_parity(v, rsb, block_offset, &offset, &buf);
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if (unlikely(IS_ERR(par)))
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return PTR_ERR(par);
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}
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}
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done:
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r = corrected;
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error:
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dm_bufio_release(buf);
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if (r < 0 && neras)
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DMERR_LIMIT("%s: FEC %llu: failed to correct: %d",
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v->data_dev->name, (unsigned long long)rsb, r);
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else if (r > 0)
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DMWARN_LIMIT("%s: FEC %llu: corrected %d errors",
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v->data_dev->name, (unsigned long long)rsb, r);
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return r;
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}
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/*
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* Locate data block erasures using verity hashes.
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*/
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static int fec_is_erasure(struct dm_verity *v, struct dm_verity_io *io,
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u8 *want_digest, u8 *data)
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{
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if (unlikely(verity_hash(v, verity_io_hash_req(v, io),
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data, 1 << v->data_dev_block_bits,
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verity_io_real_digest(v, io))))
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return 0;
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return memcmp(verity_io_real_digest(v, io), want_digest,
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v->digest_size) != 0;
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}
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/*
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* Read data blocks that are part of the RS block and deinterleave as much as
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* fits into buffers. Check for erasure locations if @neras is non-NULL.
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*/
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static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io,
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u64 rsb, u64 target, unsigned block_offset,
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int *neras)
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{
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bool is_zero;
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int i, j, target_index = -1;
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struct dm_buffer *buf;
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struct dm_bufio_client *bufio;
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struct dm_verity_fec_io *fio = fec_io(io);
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u64 block, ileaved;
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u8 *bbuf, *rs_block;
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u8 want_digest[v->digest_size];
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unsigned n, k;
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if (neras)
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*neras = 0;
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/*
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* read each of the rsn data blocks that are part of the RS block, and
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* interleave contents to available bufs
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*/
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for (i = 0; i < v->fec->rsn; i++) {
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ileaved = fec_interleave(v, rsb * v->fec->rsn + i);
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/*
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* target is the data block we want to correct, target_index is
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* the index of this block within the rsn RS blocks
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*/
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if (ileaved == target)
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target_index = i;
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block = ileaved >> v->data_dev_block_bits;
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bufio = v->fec->data_bufio;
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if (block >= v->data_blocks) {
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block -= v->data_blocks;
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/*
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* blocks outside the area were assumed to contain
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* zeros when encoding data was generated
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*/
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if (unlikely(block >= v->fec->hash_blocks))
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continue;
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block += v->hash_start;
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bufio = v->bufio;
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}
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bbuf = dm_bufio_read(bufio, block, &buf);
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if (unlikely(IS_ERR(bbuf))) {
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DMWARN_LIMIT("%s: FEC %llu: read failed (%llu): %ld",
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v->data_dev->name,
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(unsigned long long)rsb,
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(unsigned long long)block, PTR_ERR(bbuf));
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/* assume the block is corrupted */
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if (neras && *neras <= v->fec->roots)
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fio->erasures[(*neras)++] = i;
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continue;
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}
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/* locate erasures if the block is on the data device */
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if (bufio == v->fec->data_bufio &&
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verity_hash_for_block(v, io, block, want_digest,
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&is_zero) == 0) {
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/* skip known zero blocks entirely */
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if (is_zero)
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goto done;
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/*
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* skip if we have already found the theoretical
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* maximum number (i.e. fec->roots) of erasures
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*/
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if (neras && *neras <= v->fec->roots &&
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fec_is_erasure(v, io, want_digest, bbuf))
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fio->erasures[(*neras)++] = i;
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}
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/*
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* deinterleave and copy the bytes that fit into bufs,
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* starting from block_offset
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*/
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fec_for_each_buffer_rs_block(fio, n, j) {
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k = fec_buffer_rs_index(n, j) + block_offset;
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if (k >= 1 << v->data_dev_block_bits)
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goto done;
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rs_block = fec_buffer_rs_block(v, fio, n, j);
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rs_block[i] = bbuf[k];
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}
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done:
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dm_bufio_release(buf);
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}
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return target_index;
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}
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/*
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* Allocate RS control structure and FEC buffers from preallocated mempools,
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* and attempt to allocate as many extra buffers as available.
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*/
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static int fec_alloc_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio)
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{
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unsigned n;
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if (!fio->rs) {
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fio->rs = mempool_alloc(v->fec->rs_pool, 0);
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if (unlikely(!fio->rs)) {
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DMERR("failed to allocate RS");
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return -ENOMEM;
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}
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}
|
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fec_for_each_prealloc_buffer(n) {
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if (fio->bufs[n])
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continue;
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fio->bufs[n] = mempool_alloc(v->fec->prealloc_pool, GFP_NOIO);
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if (unlikely(!fio->bufs[n])) {
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DMERR("failed to allocate FEC buffer");
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return -ENOMEM;
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}
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}
|
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|
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/* try to allocate the maximum number of buffers */
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fec_for_each_extra_buffer(fio, n) {
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if (fio->bufs[n])
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continue;
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|
|
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fio->bufs[n] = mempool_alloc(v->fec->extra_pool, GFP_NOIO);
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/* we can manage with even one buffer if necessary */
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if (unlikely(!fio->bufs[n]))
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break;
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}
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fio->nbufs = n;
|
|
|
|
if (!fio->output) {
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fio->output = mempool_alloc(v->fec->output_pool, GFP_NOIO);
|
|
|
|
if (!fio->output) {
|
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DMERR("failed to allocate FEC page");
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|
return -ENOMEM;
|
|
}
|
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}
|
|
|
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return 0;
|
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}
|
|
|
|
/*
|
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* Initialize buffers and clear erasures. fec_read_bufs() assumes buffers are
|
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* zeroed before deinterleaving.
|
|
*/
|
|
static void fec_init_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio)
|
|
{
|
|
unsigned n;
|
|
|
|
fec_for_each_buffer(fio, n)
|
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memset(fio->bufs[n], 0, v->fec->rsn << DM_VERITY_FEC_BUF_RS_BITS);
|
|
|
|
memset(fio->erasures, 0, sizeof(fio->erasures));
|
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}
|
|
|
|
/*
|
|
* Decode all RS blocks in a single data block and return the target block
|
|
* (indicated by @offset) in fio->output. If @use_erasures is non-zero, uses
|
|
* hashes to locate erasures.
|
|
*/
|
|
static int fec_decode_rsb(struct dm_verity *v, struct dm_verity_io *io,
|
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struct dm_verity_fec_io *fio, u64 rsb, u64 offset,
|
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bool use_erasures)
|
|
{
|
|
int r, neras = 0;
|
|
unsigned pos;
|
|
|
|
r = fec_alloc_bufs(v, fio);
|
|
if (unlikely(r < 0))
|
|
return r;
|
|
|
|
for (pos = 0; pos < 1 << v->data_dev_block_bits; ) {
|
|
fec_init_bufs(v, fio);
|
|
|
|
r = fec_read_bufs(v, io, rsb, offset, pos,
|
|
use_erasures ? &neras : NULL);
|
|
if (unlikely(r < 0))
|
|
return r;
|
|
|
|
r = fec_decode_bufs(v, fio, rsb, r, pos, neras);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
pos += fio->nbufs << DM_VERITY_FEC_BUF_RS_BITS;
|
|
}
|
|
|
|
/* Always re-validate the corrected block against the expected hash */
|
|
r = verity_hash(v, verity_io_hash_req(v, io), fio->output,
|
|
1 << v->data_dev_block_bits,
|
|
verity_io_real_digest(v, io));
|
|
if (unlikely(r < 0))
|
|
return r;
|
|
|
|
if (memcmp(verity_io_real_digest(v, io), verity_io_want_digest(v, io),
|
|
v->digest_size)) {
|
|
DMERR_LIMIT("%s: FEC %llu: failed to correct (%d erasures)",
|
|
v->data_dev->name, (unsigned long long)rsb, neras);
|
|
return -EILSEQ;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int fec_bv_copy(struct dm_verity *v, struct dm_verity_io *io, u8 *data,
|
|
size_t len)
|
|
{
|
|
struct dm_verity_fec_io *fio = fec_io(io);
|
|
|
|
memcpy(data, &fio->output[fio->output_pos], len);
|
|
fio->output_pos += len;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Correct errors in a block. Copies corrected block to dest if non-NULL,
|
|
* otherwise to a bio_vec starting from iter.
|
|
*/
|
|
int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io,
|
|
enum verity_block_type type, sector_t block, u8 *dest,
|
|
struct bvec_iter *iter)
|
|
{
|
|
int r;
|
|
struct dm_verity_fec_io *fio = fec_io(io);
|
|
u64 offset, res, rsb;
|
|
|
|
if (!verity_fec_is_enabled(v))
|
|
return -EOPNOTSUPP;
|
|
|
|
if (fio->level >= DM_VERITY_FEC_MAX_RECURSION) {
|
|
DMWARN_LIMIT("%s: FEC: recursion too deep", v->data_dev->name);
|
|
return -EIO;
|
|
}
|
|
|
|
fio->level++;
|
|
|
|
if (type == DM_VERITY_BLOCK_TYPE_METADATA)
|
|
block += v->data_blocks;
|
|
|
|
/*
|
|
* For RS(M, N), the continuous FEC data is divided into blocks of N
|
|
* bytes. Since block size may not be divisible by N, the last block
|
|
* is zero padded when decoding.
|
|
*
|
|
* Each byte of the block is covered by a different RS(M, N) code,
|
|
* and each code is interleaved over N blocks to make it less likely
|
|
* that bursty corruption will leave us in unrecoverable state.
|
|
*/
|
|
|
|
offset = block << v->data_dev_block_bits;
|
|
res = div64_u64(offset, v->fec->rounds << v->data_dev_block_bits);
|
|
|
|
/*
|
|
* The base RS block we can feed to the interleaver to find out all
|
|
* blocks required for decoding.
|
|
*/
|
|
rsb = offset - res * (v->fec->rounds << v->data_dev_block_bits);
|
|
|
|
/*
|
|
* Locating erasures is slow, so attempt to recover the block without
|
|
* them first. Do a second attempt with erasures if the corruption is
|
|
* bad enough.
|
|
*/
|
|
r = fec_decode_rsb(v, io, fio, rsb, offset, false);
|
|
if (r < 0) {
|
|
r = fec_decode_rsb(v, io, fio, rsb, offset, true);
|
|
if (r < 0)
|
|
goto done;
|
|
}
|
|
|
|
if (dest)
|
|
memcpy(dest, fio->output, 1 << v->data_dev_block_bits);
|
|
else if (iter) {
|
|
fio->output_pos = 0;
|
|
r = verity_for_bv_block(v, io, iter, fec_bv_copy);
|
|
}
|
|
|
|
done:
|
|
fio->level--;
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* Clean up per-bio data.
|
|
*/
|
|
void verity_fec_finish_io(struct dm_verity_io *io)
|
|
{
|
|
unsigned n;
|
|
struct dm_verity_fec *f = io->v->fec;
|
|
struct dm_verity_fec_io *fio = fec_io(io);
|
|
|
|
if (!verity_fec_is_enabled(io->v))
|
|
return;
|
|
|
|
mempool_free(fio->rs, f->rs_pool);
|
|
|
|
fec_for_each_prealloc_buffer(n)
|
|
mempool_free(fio->bufs[n], f->prealloc_pool);
|
|
|
|
fec_for_each_extra_buffer(fio, n)
|
|
mempool_free(fio->bufs[n], f->extra_pool);
|
|
|
|
mempool_free(fio->output, f->output_pool);
|
|
}
|
|
|
|
/*
|
|
* Initialize per-bio data.
|
|
*/
|
|
void verity_fec_init_io(struct dm_verity_io *io)
|
|
{
|
|
struct dm_verity_fec_io *fio = fec_io(io);
|
|
|
|
if (!verity_fec_is_enabled(io->v))
|
|
return;
|
|
|
|
fio->rs = NULL;
|
|
memset(fio->bufs, 0, sizeof(fio->bufs));
|
|
fio->nbufs = 0;
|
|
fio->output = NULL;
|
|
fio->level = 0;
|
|
}
|
|
|
|
/*
|
|
* Append feature arguments and values to the status table.
|
|
*/
|
|
unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz,
|
|
char *result, unsigned maxlen)
|
|
{
|
|
if (!verity_fec_is_enabled(v))
|
|
return sz;
|
|
|
|
DMEMIT(" " DM_VERITY_OPT_FEC_DEV " %s "
|
|
DM_VERITY_OPT_FEC_BLOCKS " %llu "
|
|
DM_VERITY_OPT_FEC_START " %llu "
|
|
DM_VERITY_OPT_FEC_ROOTS " %d",
|
|
v->fec->dev->name,
|
|
(unsigned long long)v->fec->blocks,
|
|
(unsigned long long)v->fec->start,
|
|
v->fec->roots);
|
|
|
|
return sz;
|
|
}
|
|
|
|
void verity_fec_dtr(struct dm_verity *v)
|
|
{
|
|
struct dm_verity_fec *f = v->fec;
|
|
|
|
if (!verity_fec_is_enabled(v))
|
|
goto out;
|
|
|
|
mempool_destroy(f->rs_pool);
|
|
mempool_destroy(f->prealloc_pool);
|
|
mempool_destroy(f->extra_pool);
|
|
kmem_cache_destroy(f->cache);
|
|
|
|
if (f->data_bufio)
|
|
dm_bufio_client_destroy(f->data_bufio);
|
|
if (f->bufio)
|
|
dm_bufio_client_destroy(f->bufio);
|
|
|
|
if (f->dev)
|
|
dm_put_device(v->ti, f->dev);
|
|
out:
|
|
kfree(f);
|
|
v->fec = NULL;
|
|
}
|
|
|
|
static void *fec_rs_alloc(gfp_t gfp_mask, void *pool_data)
|
|
{
|
|
struct dm_verity *v = (struct dm_verity *)pool_data;
|
|
|
|
return init_rs(8, 0x11d, 0, 1, v->fec->roots);
|
|
}
|
|
|
|
static void fec_rs_free(void *element, void *pool_data)
|
|
{
|
|
struct rs_control *rs = (struct rs_control *)element;
|
|
|
|
if (rs)
|
|
free_rs(rs);
|
|
}
|
|
|
|
bool verity_is_fec_opt_arg(const char *arg_name)
|
|
{
|
|
return (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV) ||
|
|
!strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS) ||
|
|
!strcasecmp(arg_name, DM_VERITY_OPT_FEC_START) ||
|
|
!strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS));
|
|
}
|
|
|
|
int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
|
|
unsigned *argc, const char *arg_name)
|
|
{
|
|
int r;
|
|
struct dm_target *ti = v->ti;
|
|
const char *arg_value;
|
|
unsigned long long num_ll;
|
|
unsigned char num_c;
|
|
char dummy;
|
|
|
|
if (!*argc) {
|
|
ti->error = "FEC feature arguments require a value";
|
|
return -EINVAL;
|
|
}
|
|
|
|
arg_value = dm_shift_arg(as);
|
|
(*argc)--;
|
|
|
|
if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV)) {
|
|
r = dm_get_device(ti, arg_value, FMODE_READ, &v->fec->dev);
|
|
if (r) {
|
|
ti->error = "FEC device lookup failed";
|
|
return r;
|
|
}
|
|
|
|
} else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS)) {
|
|
if (sscanf(arg_value, "%llu%c", &num_ll, &dummy) != 1 ||
|
|
((sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))
|
|
>> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll)) {
|
|
ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS;
|
|
return -EINVAL;
|
|
}
|
|
v->fec->blocks = num_ll;
|
|
|
|
} else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_START)) {
|
|
if (sscanf(arg_value, "%llu%c", &num_ll, &dummy) != 1 ||
|
|
((sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) >>
|
|
(v->data_dev_block_bits - SECTOR_SHIFT) != num_ll)) {
|
|
ti->error = "Invalid " DM_VERITY_OPT_FEC_START;
|
|
return -EINVAL;
|
|
}
|
|
v->fec->start = num_ll;
|
|
|
|
} else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS)) {
|
|
if (sscanf(arg_value, "%hhu%c", &num_c, &dummy) != 1 || !num_c ||
|
|
num_c < (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MAX_RSN) ||
|
|
num_c > (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN)) {
|
|
ti->error = "Invalid " DM_VERITY_OPT_FEC_ROOTS;
|
|
return -EINVAL;
|
|
}
|
|
v->fec->roots = num_c;
|
|
|
|
} else {
|
|
ti->error = "Unrecognized verity FEC feature request";
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Allocate dm_verity_fec for v->fec. Must be called before verity_fec_ctr.
|
|
*/
|
|
int verity_fec_ctr_alloc(struct dm_verity *v)
|
|
{
|
|
struct dm_verity_fec *f;
|
|
|
|
f = kzalloc(sizeof(struct dm_verity_fec), GFP_KERNEL);
|
|
if (!f) {
|
|
v->ti->error = "Cannot allocate FEC structure";
|
|
return -ENOMEM;
|
|
}
|
|
v->fec = f;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Validate arguments and preallocate memory. Must be called after arguments
|
|
* have been parsed using verity_fec_parse_opt_args.
|
|
*/
|
|
int verity_fec_ctr(struct dm_verity *v)
|
|
{
|
|
struct dm_verity_fec *f = v->fec;
|
|
struct dm_target *ti = v->ti;
|
|
u64 hash_blocks;
|
|
|
|
if (!verity_fec_is_enabled(v)) {
|
|
verity_fec_dtr(v);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* FEC is computed over data blocks, possible metadata, and
|
|
* hash blocks. In other words, FEC covers total of fec_blocks
|
|
* blocks consisting of the following:
|
|
*
|
|
* data blocks | hash blocks | metadata (optional)
|
|
*
|
|
* We allow metadata after hash blocks to support a use case
|
|
* where all data is stored on the same device and FEC covers
|
|
* the entire area.
|
|
*
|
|
* If metadata is included, we require it to be available on the
|
|
* hash device after the hash blocks.
|
|
*/
|
|
|
|
hash_blocks = v->hash_blocks - v->hash_start;
|
|
|
|
/*
|
|
* Require matching block sizes for data and hash devices for
|
|
* simplicity.
|
|
*/
|
|
if (v->data_dev_block_bits != v->hash_dev_block_bits) {
|
|
ti->error = "Block sizes must match to use FEC";
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (!f->roots) {
|
|
ti->error = "Missing " DM_VERITY_OPT_FEC_ROOTS;
|
|
return -EINVAL;
|
|
}
|
|
f->rsn = DM_VERITY_FEC_RSM - f->roots;
|
|
|
|
if (!f->blocks) {
|
|
ti->error = "Missing " DM_VERITY_OPT_FEC_BLOCKS;
|
|
return -EINVAL;
|
|
}
|
|
|
|
f->rounds = f->blocks;
|
|
if (sector_div(f->rounds, f->rsn))
|
|
f->rounds++;
|
|
|
|
/*
|
|
* Due to optional metadata, f->blocks can be larger than
|
|
* data_blocks and hash_blocks combined.
|
|
*/
|
|
if (f->blocks < v->data_blocks + hash_blocks || !f->rounds) {
|
|
ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS;
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* Metadata is accessed through the hash device, so we require
|
|
* it to be large enough.
|
|
*/
|
|
f->hash_blocks = f->blocks - v->data_blocks;
|
|
if (dm_bufio_get_device_size(v->bufio) < f->hash_blocks) {
|
|
ti->error = "Hash device is too small for "
|
|
DM_VERITY_OPT_FEC_BLOCKS;
|
|
return -E2BIG;
|
|
}
|
|
|
|
f->bufio = dm_bufio_client_create(f->dev->bdev,
|
|
1 << v->data_dev_block_bits,
|
|
1, 0, NULL, NULL);
|
|
if (IS_ERR(f->bufio)) {
|
|
ti->error = "Cannot initialize FEC bufio client";
|
|
return PTR_ERR(f->bufio);
|
|
}
|
|
|
|
if (dm_bufio_get_device_size(f->bufio) <
|
|
((f->start + f->rounds * f->roots) >> v->data_dev_block_bits)) {
|
|
ti->error = "FEC device is too small";
|
|
return -E2BIG;
|
|
}
|
|
|
|
f->data_bufio = dm_bufio_client_create(v->data_dev->bdev,
|
|
1 << v->data_dev_block_bits,
|
|
1, 0, NULL, NULL);
|
|
if (IS_ERR(f->data_bufio)) {
|
|
ti->error = "Cannot initialize FEC data bufio client";
|
|
return PTR_ERR(f->data_bufio);
|
|
}
|
|
|
|
if (dm_bufio_get_device_size(f->data_bufio) < v->data_blocks) {
|
|
ti->error = "Data device is too small";
|
|
return -E2BIG;
|
|
}
|
|
|
|
/* Preallocate an rs_control structure for each worker thread */
|
|
f->rs_pool = mempool_create(num_online_cpus(), fec_rs_alloc,
|
|
fec_rs_free, (void *) v);
|
|
if (!f->rs_pool) {
|
|
ti->error = "Cannot allocate RS pool";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
f->cache = kmem_cache_create("dm_verity_fec_buffers",
|
|
f->rsn << DM_VERITY_FEC_BUF_RS_BITS,
|
|
0, 0, NULL);
|
|
if (!f->cache) {
|
|
ti->error = "Cannot create FEC buffer cache";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* Preallocate DM_VERITY_FEC_BUF_PREALLOC buffers for each thread */
|
|
f->prealloc_pool = mempool_create_slab_pool(num_online_cpus() *
|
|
DM_VERITY_FEC_BUF_PREALLOC,
|
|
f->cache);
|
|
if (!f->prealloc_pool) {
|
|
ti->error = "Cannot allocate FEC buffer prealloc pool";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
f->extra_pool = mempool_create_slab_pool(0, f->cache);
|
|
if (!f->extra_pool) {
|
|
ti->error = "Cannot allocate FEC buffer extra pool";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* Preallocate an output buffer for each thread */
|
|
f->output_pool = mempool_create_kmalloc_pool(num_online_cpus(),
|
|
1 << v->data_dev_block_bits);
|
|
if (!f->output_pool) {
|
|
ti->error = "Cannot allocate FEC output pool";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* Reserve space for our per-bio data */
|
|
ti->per_io_data_size += sizeof(struct dm_verity_fec_io);
|
|
|
|
return 0;
|
|
}
|