| /* |
| * CDDL HEADER START |
| * |
| * The contents of this file are subject to the terms of the |
| * Common Development and Distribution License (the "License"). |
| * You may not use this file except in compliance with the License. |
| * |
| * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE |
| * or http://www.opensolaris.org/os/licensing. |
| * See the License for the specific language governing permissions |
| * and limitations under the License. |
| * |
| * When distributing Covered Code, include this CDDL HEADER in each |
| * file and include the License file at usr/src/OPENSOLARIS.LICENSE. |
| * If applicable, add the following below this CDDL HEADER, with the |
| * fields enclosed by brackets "[]" replaced with your own identifying |
| * information: Portions Copyright [yyyy] [name of copyright owner] |
| * |
| * CDDL HEADER END |
| */ |
| |
| /* |
| * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. |
| * Copyright (c) 2012, 2014 by Delphix. All rights reserved. |
| * Copyright (c) 2016 Gvozden Nešković. All rights reserved. |
| */ |
| |
| #include <sys/zfs_context.h> |
| #include <sys/spa.h> |
| #include <sys/vdev_impl.h> |
| #include <sys/zio.h> |
| #include <sys/zio_checksum.h> |
| #include <sys/abd.h> |
| #include <sys/fs/zfs.h> |
| #include <sys/fm/fs/zfs.h> |
| #include <sys/vdev_raidz.h> |
| #include <sys/vdev_raidz_impl.h> |
| |
| #ifdef ZFS_DEBUG |
| #include <sys/vdev.h> /* For vdev_xlate() in vdev_raidz_io_verify() */ |
| #endif |
| |
| /* |
| * Virtual device vector for RAID-Z. |
| * |
| * This vdev supports single, double, and triple parity. For single parity, |
| * we use a simple XOR of all the data columns. For double or triple parity, |
| * we use a special case of Reed-Solomon coding. This extends the |
| * technique described in "The mathematics of RAID-6" by H. Peter Anvin by |
| * drawing on the system described in "A Tutorial on Reed-Solomon Coding for |
| * Fault-Tolerance in RAID-like Systems" by James S. Plank on which the |
| * former is also based. The latter is designed to provide higher performance |
| * for writes. |
| * |
| * Note that the Plank paper claimed to support arbitrary N+M, but was then |
| * amended six years later identifying a critical flaw that invalidates its |
| * claims. Nevertheless, the technique can be adapted to work for up to |
| * triple parity. For additional parity, the amendment "Note: Correction to |
| * the 1997 Tutorial on Reed-Solomon Coding" by James S. Plank and Ying Ding |
| * is viable, but the additional complexity means that write performance will |
| * suffer. |
| * |
| * All of the methods above operate on a Galois field, defined over the |
| * integers mod 2^N. In our case we choose N=8 for GF(8) so that all elements |
| * can be expressed with a single byte. Briefly, the operations on the |
| * field are defined as follows: |
| * |
| * o addition (+) is represented by a bitwise XOR |
| * o subtraction (-) is therefore identical to addition: A + B = A - B |
| * o multiplication of A by 2 is defined by the following bitwise expression: |
| * |
| * (A * 2)_7 = A_6 |
| * (A * 2)_6 = A_5 |
| * (A * 2)_5 = A_4 |
| * (A * 2)_4 = A_3 + A_7 |
| * (A * 2)_3 = A_2 + A_7 |
| * (A * 2)_2 = A_1 + A_7 |
| * (A * 2)_1 = A_0 |
| * (A * 2)_0 = A_7 |
| * |
| * In C, multiplying by 2 is therefore ((a << 1) ^ ((a & 0x80) ? 0x1d : 0)). |
| * As an aside, this multiplication is derived from the error correcting |
| * primitive polynomial x^8 + x^4 + x^3 + x^2 + 1. |
| * |
| * Observe that any number in the field (except for 0) can be expressed as a |
| * power of 2 -- a generator for the field. We store a table of the powers of |
| * 2 and logs base 2 for quick look ups, and exploit the fact that A * B can |
| * be rewritten as 2^(log_2(A) + log_2(B)) (where '+' is normal addition rather |
| * than field addition). The inverse of a field element A (A^-1) is therefore |
| * A ^ (255 - 1) = A^254. |
| * |
| * The up-to-three parity columns, P, Q, R over several data columns, |
| * D_0, ... D_n-1, can be expressed by field operations: |
| * |
| * P = D_0 + D_1 + ... + D_n-2 + D_n-1 |
| * Q = 2^n-1 * D_0 + 2^n-2 * D_1 + ... + 2^1 * D_n-2 + 2^0 * D_n-1 |
| * = ((...((D_0) * 2 + D_1) * 2 + ...) * 2 + D_n-2) * 2 + D_n-1 |
| * R = 4^n-1 * D_0 + 4^n-2 * D_1 + ... + 4^1 * D_n-2 + 4^0 * D_n-1 |
| * = ((...((D_0) * 4 + D_1) * 4 + ...) * 4 + D_n-2) * 4 + D_n-1 |
| * |
| * We chose 1, 2, and 4 as our generators because 1 corresponds to the trivial |
| * XOR operation, and 2 and 4 can be computed quickly and generate linearly- |
| * independent coefficients. (There are no additional coefficients that have |
| * this property which is why the uncorrected Plank method breaks down.) |
| * |
| * See the reconstruction code below for how P, Q and R can used individually |
| * or in concert to recover missing data columns. |
| */ |
| |
| #define VDEV_RAIDZ_P 0 |
| #define VDEV_RAIDZ_Q 1 |
| #define VDEV_RAIDZ_R 2 |
| |
| #define VDEV_RAIDZ_MUL_2(x) (((x) << 1) ^ (((x) & 0x80) ? 0x1d : 0)) |
| #define VDEV_RAIDZ_MUL_4(x) (VDEV_RAIDZ_MUL_2(VDEV_RAIDZ_MUL_2(x))) |
| |
| /* |
| * We provide a mechanism to perform the field multiplication operation on a |
| * 64-bit value all at once rather than a byte at a time. This works by |
| * creating a mask from the top bit in each byte and using that to |
| * conditionally apply the XOR of 0x1d. |
| */ |
| #define VDEV_RAIDZ_64MUL_2(x, mask) \ |
| { \ |
| (mask) = (x) & 0x8080808080808080ULL; \ |
| (mask) = ((mask) << 1) - ((mask) >> 7); \ |
| (x) = (((x) << 1) & 0xfefefefefefefefeULL) ^ \ |
| ((mask) & 0x1d1d1d1d1d1d1d1dULL); \ |
| } |
| |
| #define VDEV_RAIDZ_64MUL_4(x, mask) \ |
| { \ |
| VDEV_RAIDZ_64MUL_2((x), mask); \ |
| VDEV_RAIDZ_64MUL_2((x), mask); \ |
| } |
| |
| void |
| vdev_raidz_map_free(raidz_map_t *rm) |
| { |
| int c; |
| |
| for (c = 0; c < rm->rm_firstdatacol; c++) { |
| abd_free(rm->rm_col[c].rc_abd); |
| |
| if (rm->rm_col[c].rc_gdata != NULL) |
| abd_free(rm->rm_col[c].rc_gdata); |
| } |
| |
| for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) |
| abd_put(rm->rm_col[c].rc_abd); |
| |
| if (rm->rm_abd_copy != NULL) |
| abd_free(rm->rm_abd_copy); |
| |
| kmem_free(rm, offsetof(raidz_map_t, rm_col[rm->rm_scols])); |
| } |
| |
| static void |
| vdev_raidz_map_free_vsd(zio_t *zio) |
| { |
| raidz_map_t *rm = zio->io_vsd; |
| |
| ASSERT0(rm->rm_freed); |
| rm->rm_freed = 1; |
| |
| if (rm->rm_reports == 0) |
| vdev_raidz_map_free(rm); |
| } |
| |
| /*ARGSUSED*/ |
| static void |
| vdev_raidz_cksum_free(void *arg, size_t ignored) |
| { |
| raidz_map_t *rm = arg; |
| |
| ASSERT3U(rm->rm_reports, >, 0); |
| |
| if (--rm->rm_reports == 0 && rm->rm_freed != 0) |
| vdev_raidz_map_free(rm); |
| } |
| |
| static void |
| vdev_raidz_cksum_finish(zio_cksum_report_t *zcr, const abd_t *good_data) |
| { |
| raidz_map_t *rm = zcr->zcr_cbdata; |
| const size_t c = zcr->zcr_cbinfo; |
| size_t x, offset; |
| |
| const abd_t *good = NULL; |
| const abd_t *bad = rm->rm_col[c].rc_abd; |
| |
| if (good_data == NULL) { |
| zfs_ereport_finish_checksum(zcr, NULL, NULL, B_FALSE); |
| return; |
| } |
| |
| if (c < rm->rm_firstdatacol) { |
| /* |
| * The first time through, calculate the parity blocks for |
| * the good data (this relies on the fact that the good |
| * data never changes for a given logical ZIO) |
| */ |
| if (rm->rm_col[0].rc_gdata == NULL) { |
| abd_t *bad_parity[VDEV_RAIDZ_MAXPARITY]; |
| |
| /* |
| * Set up the rm_col[]s to generate the parity for |
| * good_data, first saving the parity bufs and |
| * replacing them with buffers to hold the result. |
| */ |
| for (x = 0; x < rm->rm_firstdatacol; x++) { |
| bad_parity[x] = rm->rm_col[x].rc_abd; |
| rm->rm_col[x].rc_abd = |
| rm->rm_col[x].rc_gdata = |
| abd_alloc_sametype(rm->rm_col[x].rc_abd, |
| rm->rm_col[x].rc_size); |
| } |
| |
| /* fill in the data columns from good_data */ |
| offset = 0; |
| for (; x < rm->rm_cols; x++) { |
| abd_put(rm->rm_col[x].rc_abd); |
| |
| rm->rm_col[x].rc_abd = |
| abd_get_offset_size((abd_t *)good_data, |
| offset, rm->rm_col[x].rc_size); |
| offset += rm->rm_col[x].rc_size; |
| } |
| |
| /* |
| * Construct the parity from the good data. |
| */ |
| vdev_raidz_generate_parity(rm); |
| |
| /* restore everything back to its original state */ |
| for (x = 0; x < rm->rm_firstdatacol; x++) |
| rm->rm_col[x].rc_abd = bad_parity[x]; |
| |
| offset = 0; |
| for (x = rm->rm_firstdatacol; x < rm->rm_cols; x++) { |
| abd_put(rm->rm_col[x].rc_abd); |
| rm->rm_col[x].rc_abd = abd_get_offset_size( |
| rm->rm_abd_copy, offset, |
| rm->rm_col[x].rc_size); |
| offset += rm->rm_col[x].rc_size; |
| } |
| } |
| |
| ASSERT3P(rm->rm_col[c].rc_gdata, !=, NULL); |
| good = abd_get_offset_size(rm->rm_col[c].rc_gdata, 0, |
| rm->rm_col[c].rc_size); |
| } else { |
| /* adjust good_data to point at the start of our column */ |
| offset = 0; |
| for (x = rm->rm_firstdatacol; x < c; x++) |
| offset += rm->rm_col[x].rc_size; |
| |
| good = abd_get_offset_size((abd_t *)good_data, offset, |
| rm->rm_col[c].rc_size); |
| } |
| |
| /* we drop the ereport if it ends up that the data was good */ |
| zfs_ereport_finish_checksum(zcr, good, bad, B_TRUE); |
| abd_put((abd_t *)good); |
| } |
| |
| /* |
| * Invoked indirectly by zfs_ereport_start_checksum(), called |
| * below when our read operation fails completely. The main point |
| * is to keep a copy of everything we read from disk, so that at |
| * vdev_raidz_cksum_finish() time we can compare it with the good data. |
| */ |
| static void |
| vdev_raidz_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *arg) |
| { |
| size_t c = (size_t)(uintptr_t)arg; |
| size_t offset; |
| |
| raidz_map_t *rm = zio->io_vsd; |
| size_t size; |
| |
| /* set up the report and bump the refcount */ |
| zcr->zcr_cbdata = rm; |
| zcr->zcr_cbinfo = c; |
| zcr->zcr_finish = vdev_raidz_cksum_finish; |
| zcr->zcr_free = vdev_raidz_cksum_free; |
| |
| rm->rm_reports++; |
| ASSERT3U(rm->rm_reports, >, 0); |
| |
| if (rm->rm_abd_copy != NULL) |
| return; |
| |
| /* |
| * It's the first time we're called for this raidz_map_t, so we need |
| * to copy the data aside; there's no guarantee that our zio's buffer |
| * won't be re-used for something else. |
| * |
| * Our parity data is already in separate buffers, so there's no need |
| * to copy them. |
| */ |
| |
| size = 0; |
| for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) |
| size += rm->rm_col[c].rc_size; |
| |
| rm->rm_abd_copy = abd_alloc_for_io(size, B_FALSE); |
| |
| for (offset = 0, c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
| raidz_col_t *col = &rm->rm_col[c]; |
| abd_t *tmp = abd_get_offset_size(rm->rm_abd_copy, offset, |
| col->rc_size); |
| |
| abd_copy(tmp, col->rc_abd, col->rc_size); |
| |
| abd_put(col->rc_abd); |
| col->rc_abd = tmp; |
| |
| offset += col->rc_size; |
| } |
| ASSERT3U(offset, ==, size); |
| } |
| |
| static const zio_vsd_ops_t vdev_raidz_vsd_ops = { |
| .vsd_free = vdev_raidz_map_free_vsd, |
| .vsd_cksum_report = vdev_raidz_cksum_report |
| }; |
| |
| /* |
| * Divides the IO evenly across all child vdevs; usually, dcols is |
| * the number of children in the target vdev. |
| * |
| * Avoid inlining the function to keep vdev_raidz_io_start(), which |
| * is this functions only caller, as small as possible on the stack. |
| */ |
| noinline raidz_map_t * |
| vdev_raidz_map_alloc(zio_t *zio, uint64_t ashift, uint64_t dcols, |
| uint64_t nparity) |
| { |
| raidz_map_t *rm; |
| /* The starting RAIDZ (parent) vdev sector of the block. */ |
| uint64_t b = zio->io_offset >> ashift; |
| /* The zio's size in units of the vdev's minimum sector size. */ |
| uint64_t s = zio->io_size >> ashift; |
| /* The first column for this stripe. */ |
| uint64_t f = b % dcols; |
| /* The starting byte offset on each child vdev. */ |
| uint64_t o = (b / dcols) << ashift; |
| uint64_t q, r, c, bc, col, acols, scols, coff, devidx, asize, tot; |
| uint64_t off = 0; |
| |
| /* |
| * "Quotient": The number of data sectors for this stripe on all but |
| * the "big column" child vdevs that also contain "remainder" data. |
| */ |
| q = s / (dcols - nparity); |
| |
| /* |
| * "Remainder": The number of partial stripe data sectors in this I/O. |
| * This will add a sector to some, but not all, child vdevs. |
| */ |
| r = s - q * (dcols - nparity); |
| |
| /* The number of "big columns" - those which contain remainder data. */ |
| bc = (r == 0 ? 0 : r + nparity); |
| |
| /* |
| * The total number of data and parity sectors associated with |
| * this I/O. |
| */ |
| tot = s + nparity * (q + (r == 0 ? 0 : 1)); |
| |
| /* acols: The columns that will be accessed. */ |
| /* scols: The columns that will be accessed or skipped. */ |
| if (q == 0) { |
| /* Our I/O request doesn't span all child vdevs. */ |
| acols = bc; |
| scols = MIN(dcols, roundup(bc, nparity + 1)); |
| } else { |
| acols = dcols; |
| scols = dcols; |
| } |
| |
| ASSERT3U(acols, <=, scols); |
| |
| rm = kmem_alloc(offsetof(raidz_map_t, rm_col[scols]), KM_SLEEP); |
| |
| rm->rm_cols = acols; |
| rm->rm_scols = scols; |
| rm->rm_bigcols = bc; |
| rm->rm_skipstart = bc; |
| rm->rm_missingdata = 0; |
| rm->rm_missingparity = 0; |
| rm->rm_firstdatacol = nparity; |
| rm->rm_abd_copy = NULL; |
| rm->rm_reports = 0; |
| rm->rm_freed = 0; |
| rm->rm_ecksuminjected = 0; |
| |
| asize = 0; |
| |
| for (c = 0; c < scols; c++) { |
| col = f + c; |
| coff = o; |
| if (col >= dcols) { |
| col -= dcols; |
| coff += 1ULL << ashift; |
| } |
| rm->rm_col[c].rc_devidx = col; |
| rm->rm_col[c].rc_offset = coff; |
| rm->rm_col[c].rc_abd = NULL; |
| rm->rm_col[c].rc_gdata = NULL; |
| rm->rm_col[c].rc_error = 0; |
| rm->rm_col[c].rc_tried = 0; |
| rm->rm_col[c].rc_skipped = 0; |
| |
| if (c >= acols) |
| rm->rm_col[c].rc_size = 0; |
| else if (c < bc) |
| rm->rm_col[c].rc_size = (q + 1) << ashift; |
| else |
| rm->rm_col[c].rc_size = q << ashift; |
| |
| asize += rm->rm_col[c].rc_size; |
| } |
| |
| ASSERT3U(asize, ==, tot << ashift); |
| rm->rm_asize = roundup(asize, (nparity + 1) << ashift); |
| rm->rm_nskip = roundup(tot, nparity + 1) - tot; |
| ASSERT3U(rm->rm_asize - asize, ==, rm->rm_nskip << ashift); |
| ASSERT3U(rm->rm_nskip, <=, nparity); |
| |
| for (c = 0; c < rm->rm_firstdatacol; c++) |
| rm->rm_col[c].rc_abd = |
| abd_alloc_linear(rm->rm_col[c].rc_size, B_FALSE); |
| |
| rm->rm_col[c].rc_abd = abd_get_offset_size(zio->io_abd, 0, |
| rm->rm_col[c].rc_size); |
| off = rm->rm_col[c].rc_size; |
| |
| for (c = c + 1; c < acols; c++) { |
| rm->rm_col[c].rc_abd = abd_get_offset_size(zio->io_abd, off, |
| rm->rm_col[c].rc_size); |
| off += rm->rm_col[c].rc_size; |
| } |
| |
| /* |
| * If all data stored spans all columns, there's a danger that parity |
| * will always be on the same device and, since parity isn't read |
| * during normal operation, that device's I/O bandwidth won't be |
| * used effectively. We therefore switch the parity every 1MB. |
| * |
| * ... at least that was, ostensibly, the theory. As a practical |
| * matter unless we juggle the parity between all devices evenly, we |
| * won't see any benefit. Further, occasional writes that aren't a |
| * multiple of the LCM of the number of children and the minimum |
| * stripe width are sufficient to avoid pessimal behavior. |
| * Unfortunately, this decision created an implicit on-disk format |
| * requirement that we need to support for all eternity, but only |
| * for single-parity RAID-Z. |
| * |
| * If we intend to skip a sector in the zeroth column for padding |
| * we must make sure to note this swap. We will never intend to |
| * skip the first column since at least one data and one parity |
| * column must appear in each row. |
| */ |
| ASSERT(rm->rm_cols >= 2); |
| ASSERT(rm->rm_col[0].rc_size == rm->rm_col[1].rc_size); |
| |
| if (rm->rm_firstdatacol == 1 && (zio->io_offset & (1ULL << 20))) { |
| devidx = rm->rm_col[0].rc_devidx; |
| o = rm->rm_col[0].rc_offset; |
| rm->rm_col[0].rc_devidx = rm->rm_col[1].rc_devidx; |
| rm->rm_col[0].rc_offset = rm->rm_col[1].rc_offset; |
| rm->rm_col[1].rc_devidx = devidx; |
| rm->rm_col[1].rc_offset = o; |
| |
| if (rm->rm_skipstart == 0) |
| rm->rm_skipstart = 1; |
| } |
| |
| zio->io_vsd = rm; |
| zio->io_vsd_ops = &vdev_raidz_vsd_ops; |
| |
| /* init RAIDZ parity ops */ |
| rm->rm_ops = vdev_raidz_math_get_ops(); |
| |
| return (rm); |
| } |
| |
| struct pqr_struct { |
| uint64_t *p; |
| uint64_t *q; |
| uint64_t *r; |
| }; |
| |
| static int |
| vdev_raidz_p_func(void *buf, size_t size, void *private) |
| { |
| struct pqr_struct *pqr = private; |
| const uint64_t *src = buf; |
| int i, cnt = size / sizeof (src[0]); |
| |
| ASSERT(pqr->p && !pqr->q && !pqr->r); |
| |
| for (i = 0; i < cnt; i++, src++, pqr->p++) |
| *pqr->p ^= *src; |
| |
| return (0); |
| } |
| |
| static int |
| vdev_raidz_pq_func(void *buf, size_t size, void *private) |
| { |
| struct pqr_struct *pqr = private; |
| const uint64_t *src = buf; |
| uint64_t mask; |
| int i, cnt = size / sizeof (src[0]); |
| |
| ASSERT(pqr->p && pqr->q && !pqr->r); |
| |
| for (i = 0; i < cnt; i++, src++, pqr->p++, pqr->q++) { |
| *pqr->p ^= *src; |
| VDEV_RAIDZ_64MUL_2(*pqr->q, mask); |
| *pqr->q ^= *src; |
| } |
| |
| return (0); |
| } |
| |
| static int |
| vdev_raidz_pqr_func(void *buf, size_t size, void *private) |
| { |
| struct pqr_struct *pqr = private; |
| const uint64_t *src = buf; |
| uint64_t mask; |
| int i, cnt = size / sizeof (src[0]); |
| |
| ASSERT(pqr->p && pqr->q && pqr->r); |
| |
| for (i = 0; i < cnt; i++, src++, pqr->p++, pqr->q++, pqr->r++) { |
| *pqr->p ^= *src; |
| VDEV_RAIDZ_64MUL_2(*pqr->q, mask); |
| *pqr->q ^= *src; |
| VDEV_RAIDZ_64MUL_4(*pqr->r, mask); |
| *pqr->r ^= *src; |
| } |
| |
| return (0); |
| } |
| |
| static void |
| vdev_raidz_generate_parity_p(raidz_map_t *rm) |
| { |
| uint64_t *p; |
| int c; |
| abd_t *src; |
| |
| for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
| src = rm->rm_col[c].rc_abd; |
| p = abd_to_buf(rm->rm_col[VDEV_RAIDZ_P].rc_abd); |
| |
| if (c == rm->rm_firstdatacol) { |
| abd_copy_to_buf(p, src, rm->rm_col[c].rc_size); |
| } else { |
| struct pqr_struct pqr = { p, NULL, NULL }; |
| (void) abd_iterate_func(src, 0, rm->rm_col[c].rc_size, |
| vdev_raidz_p_func, &pqr); |
| } |
| } |
| } |
| |
| static void |
| vdev_raidz_generate_parity_pq(raidz_map_t *rm) |
| { |
| uint64_t *p, *q, pcnt, ccnt, mask, i; |
| int c; |
| abd_t *src; |
| |
| pcnt = rm->rm_col[VDEV_RAIDZ_P].rc_size / sizeof (p[0]); |
| ASSERT(rm->rm_col[VDEV_RAIDZ_P].rc_size == |
| rm->rm_col[VDEV_RAIDZ_Q].rc_size); |
| |
| for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
| src = rm->rm_col[c].rc_abd; |
| p = abd_to_buf(rm->rm_col[VDEV_RAIDZ_P].rc_abd); |
| q = abd_to_buf(rm->rm_col[VDEV_RAIDZ_Q].rc_abd); |
| |
| ccnt = rm->rm_col[c].rc_size / sizeof (p[0]); |
| |
| if (c == rm->rm_firstdatacol) { |
| ASSERT(ccnt == pcnt || ccnt == 0); |
| abd_copy_to_buf(p, src, rm->rm_col[c].rc_size); |
| (void) memcpy(q, p, rm->rm_col[c].rc_size); |
| |
| for (i = ccnt; i < pcnt; i++) { |
| p[i] = 0; |
| q[i] = 0; |
| } |
| } else { |
| struct pqr_struct pqr = { p, q, NULL }; |
| |
| ASSERT(ccnt <= pcnt); |
| (void) abd_iterate_func(src, 0, rm->rm_col[c].rc_size, |
| vdev_raidz_pq_func, &pqr); |
| |
| /* |
| * Treat short columns as though they are full of 0s. |
| * Note that there's therefore nothing needed for P. |
| */ |
| for (i = ccnt; i < pcnt; i++) { |
| VDEV_RAIDZ_64MUL_2(q[i], mask); |
| } |
| } |
| } |
| } |
| |
| static void |
| vdev_raidz_generate_parity_pqr(raidz_map_t *rm) |
| { |
| uint64_t *p, *q, *r, pcnt, ccnt, mask, i; |
| int c; |
| abd_t *src; |
| |
| pcnt = rm->rm_col[VDEV_RAIDZ_P].rc_size / sizeof (p[0]); |
| ASSERT(rm->rm_col[VDEV_RAIDZ_P].rc_size == |
| rm->rm_col[VDEV_RAIDZ_Q].rc_size); |
| ASSERT(rm->rm_col[VDEV_RAIDZ_P].rc_size == |
| rm->rm_col[VDEV_RAIDZ_R].rc_size); |
| |
| for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
| src = rm->rm_col[c].rc_abd; |
| p = abd_to_buf(rm->rm_col[VDEV_RAIDZ_P].rc_abd); |
| q = abd_to_buf(rm->rm_col[VDEV_RAIDZ_Q].rc_abd); |
| r = abd_to_buf(rm->rm_col[VDEV_RAIDZ_R].rc_abd); |
| |
| ccnt = rm->rm_col[c].rc_size / sizeof (p[0]); |
| |
| if (c == rm->rm_firstdatacol) { |
| ASSERT(ccnt == pcnt || ccnt == 0); |
| abd_copy_to_buf(p, src, rm->rm_col[c].rc_size); |
| (void) memcpy(q, p, rm->rm_col[c].rc_size); |
| (void) memcpy(r, p, rm->rm_col[c].rc_size); |
| |
| for (i = ccnt; i < pcnt; i++) { |
| p[i] = 0; |
| q[i] = 0; |
| r[i] = 0; |
| } |
| } else { |
| struct pqr_struct pqr = { p, q, r }; |
| |
| ASSERT(ccnt <= pcnt); |
| (void) abd_iterate_func(src, 0, rm->rm_col[c].rc_size, |
| vdev_raidz_pqr_func, &pqr); |
| |
| /* |
| * Treat short columns as though they are full of 0s. |
| * Note that there's therefore nothing needed for P. |
| */ |
| for (i = ccnt; i < pcnt; i++) { |
| VDEV_RAIDZ_64MUL_2(q[i], mask); |
| VDEV_RAIDZ_64MUL_4(r[i], mask); |
| } |
| } |
| } |
| } |
| |
| /* |
| * Generate RAID parity in the first virtual columns according to the number of |
| * parity columns available. |
| */ |
| void |
| vdev_raidz_generate_parity(raidz_map_t *rm) |
| { |
| /* Generate using the new math implementation */ |
| if (vdev_raidz_math_generate(rm) != RAIDZ_ORIGINAL_IMPL) |
| return; |
| |
| switch (rm->rm_firstdatacol) { |
| case 1: |
| vdev_raidz_generate_parity_p(rm); |
| break; |
| case 2: |
| vdev_raidz_generate_parity_pq(rm); |
| break; |
| case 3: |
| vdev_raidz_generate_parity_pqr(rm); |
| break; |
| default: |
| cmn_err(CE_PANIC, "invalid RAID-Z configuration"); |
| } |
| } |
| |
| /* ARGSUSED */ |
| static int |
| vdev_raidz_reconst_p_func(void *dbuf, void *sbuf, size_t size, void *private) |
| { |
| uint64_t *dst = dbuf; |
| uint64_t *src = sbuf; |
| int cnt = size / sizeof (src[0]); |
| |
| for (int i = 0; i < cnt; i++) { |
| dst[i] ^= src[i]; |
| } |
| |
| return (0); |
| } |
| |
| /* ARGSUSED */ |
| static int |
| vdev_raidz_reconst_q_pre_func(void *dbuf, void *sbuf, size_t size, |
| void *private) |
| { |
| uint64_t *dst = dbuf; |
| uint64_t *src = sbuf; |
| uint64_t mask; |
| int cnt = size / sizeof (dst[0]); |
| |
| for (int i = 0; i < cnt; i++, dst++, src++) { |
| VDEV_RAIDZ_64MUL_2(*dst, mask); |
| *dst ^= *src; |
| } |
| |
| return (0); |
| } |
| |
| /* ARGSUSED */ |
| static int |
| vdev_raidz_reconst_q_pre_tail_func(void *buf, size_t size, void *private) |
| { |
| uint64_t *dst = buf; |
| uint64_t mask; |
| int cnt = size / sizeof (dst[0]); |
| |
| for (int i = 0; i < cnt; i++, dst++) { |
| /* same operation as vdev_raidz_reconst_q_pre_func() on dst */ |
| VDEV_RAIDZ_64MUL_2(*dst, mask); |
| } |
| |
| return (0); |
| } |
| |
| struct reconst_q_struct { |
| uint64_t *q; |
| int exp; |
| }; |
| |
| static int |
| vdev_raidz_reconst_q_post_func(void *buf, size_t size, void *private) |
| { |
| struct reconst_q_struct *rq = private; |
| uint64_t *dst = buf; |
| int cnt = size / sizeof (dst[0]); |
| |
| for (int i = 0; i < cnt; i++, dst++, rq->q++) { |
| int j; |
| uint8_t *b; |
| |
| *dst ^= *rq->q; |
| for (j = 0, b = (uint8_t *)dst; j < 8; j++, b++) { |
| *b = vdev_raidz_exp2(*b, rq->exp); |
| } |
| } |
| |
| return (0); |
| } |
| |
| struct reconst_pq_struct { |
| uint8_t *p; |
| uint8_t *q; |
| uint8_t *pxy; |
| uint8_t *qxy; |
| int aexp; |
| int bexp; |
| }; |
| |
| static int |
| vdev_raidz_reconst_pq_func(void *xbuf, void *ybuf, size_t size, void *private) |
| { |
| struct reconst_pq_struct *rpq = private; |
| uint8_t *xd = xbuf; |
| uint8_t *yd = ybuf; |
| |
| for (int i = 0; i < size; |
| i++, rpq->p++, rpq->q++, rpq->pxy++, rpq->qxy++, xd++, yd++) { |
| *xd = vdev_raidz_exp2(*rpq->p ^ *rpq->pxy, rpq->aexp) ^ |
| vdev_raidz_exp2(*rpq->q ^ *rpq->qxy, rpq->bexp); |
| *yd = *rpq->p ^ *rpq->pxy ^ *xd; |
| } |
| |
| return (0); |
| } |
| |
| static int |
| vdev_raidz_reconst_pq_tail_func(void *xbuf, size_t size, void *private) |
| { |
| struct reconst_pq_struct *rpq = private; |
| uint8_t *xd = xbuf; |
| |
| for (int i = 0; i < size; |
| i++, rpq->p++, rpq->q++, rpq->pxy++, rpq->qxy++, xd++) { |
| /* same operation as vdev_raidz_reconst_pq_func() on xd */ |
| *xd = vdev_raidz_exp2(*rpq->p ^ *rpq->pxy, rpq->aexp) ^ |
| vdev_raidz_exp2(*rpq->q ^ *rpq->qxy, rpq->bexp); |
| } |
| |
| return (0); |
| } |
| |
| static int |
| vdev_raidz_reconstruct_p(raidz_map_t *rm, int *tgts, int ntgts) |
| { |
| int x = tgts[0]; |
| int c; |
| abd_t *dst, *src; |
| |
| ASSERT(ntgts == 1); |
| ASSERT(x >= rm->rm_firstdatacol); |
| ASSERT(x < rm->rm_cols); |
| |
| ASSERT(rm->rm_col[x].rc_size <= rm->rm_col[VDEV_RAIDZ_P].rc_size); |
| ASSERT(rm->rm_col[x].rc_size > 0); |
| |
| src = rm->rm_col[VDEV_RAIDZ_P].rc_abd; |
| dst = rm->rm_col[x].rc_abd; |
| |
| abd_copy_from_buf(dst, abd_to_buf(src), rm->rm_col[x].rc_size); |
| |
| for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
| uint64_t size = MIN(rm->rm_col[x].rc_size, |
| rm->rm_col[c].rc_size); |
| |
| src = rm->rm_col[c].rc_abd; |
| dst = rm->rm_col[x].rc_abd; |
| |
| if (c == x) |
| continue; |
| |
| (void) abd_iterate_func2(dst, src, 0, 0, size, |
| vdev_raidz_reconst_p_func, NULL); |
| } |
| |
| return (1 << VDEV_RAIDZ_P); |
| } |
| |
| static int |
| vdev_raidz_reconstruct_q(raidz_map_t *rm, int *tgts, int ntgts) |
| { |
| int x = tgts[0]; |
| int c, exp; |
| abd_t *dst, *src; |
| |
| ASSERT(ntgts == 1); |
| |
| ASSERT(rm->rm_col[x].rc_size <= rm->rm_col[VDEV_RAIDZ_Q].rc_size); |
| |
| for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
| uint64_t size = (c == x) ? 0 : MIN(rm->rm_col[x].rc_size, |
| rm->rm_col[c].rc_size); |
| |
| src = rm->rm_col[c].rc_abd; |
| dst = rm->rm_col[x].rc_abd; |
| |
| if (c == rm->rm_firstdatacol) { |
| abd_copy(dst, src, size); |
| if (rm->rm_col[x].rc_size > size) |
| abd_zero_off(dst, size, |
| rm->rm_col[x].rc_size - size); |
| |
| } else { |
| ASSERT3U(size, <=, rm->rm_col[x].rc_size); |
| (void) abd_iterate_func2(dst, src, 0, 0, size, |
| vdev_raidz_reconst_q_pre_func, NULL); |
| (void) abd_iterate_func(dst, |
| size, rm->rm_col[x].rc_size - size, |
| vdev_raidz_reconst_q_pre_tail_func, NULL); |
| } |
| } |
| |
| src = rm->rm_col[VDEV_RAIDZ_Q].rc_abd; |
| dst = rm->rm_col[x].rc_abd; |
| exp = 255 - (rm->rm_cols - 1 - x); |
| |
| struct reconst_q_struct rq = { abd_to_buf(src), exp }; |
| (void) abd_iterate_func(dst, 0, rm->rm_col[x].rc_size, |
| vdev_raidz_reconst_q_post_func, &rq); |
| |
| return (1 << VDEV_RAIDZ_Q); |
| } |
| |
| static int |
| vdev_raidz_reconstruct_pq(raidz_map_t *rm, int *tgts, int ntgts) |
| { |
| uint8_t *p, *q, *pxy, *qxy, tmp, a, b, aexp, bexp; |
| abd_t *pdata, *qdata; |
| uint64_t xsize, ysize; |
| int x = tgts[0]; |
| int y = tgts[1]; |
| abd_t *xd, *yd; |
| |
| ASSERT(ntgts == 2); |
| ASSERT(x < y); |
| ASSERT(x >= rm->rm_firstdatacol); |
| ASSERT(y < rm->rm_cols); |
| |
| ASSERT(rm->rm_col[x].rc_size >= rm->rm_col[y].rc_size); |
| |
| /* |
| * Move the parity data aside -- we're going to compute parity as |
| * though columns x and y were full of zeros -- Pxy and Qxy. We want to |
| * reuse the parity generation mechanism without trashing the actual |
| * parity so we make those columns appear to be full of zeros by |
| * setting their lengths to zero. |
| */ |
| pdata = rm->rm_col[VDEV_RAIDZ_P].rc_abd; |
| qdata = rm->rm_col[VDEV_RAIDZ_Q].rc_abd; |
| xsize = rm->rm_col[x].rc_size; |
| ysize = rm->rm_col[y].rc_size; |
| |
| rm->rm_col[VDEV_RAIDZ_P].rc_abd = |
| abd_alloc_linear(rm->rm_col[VDEV_RAIDZ_P].rc_size, B_TRUE); |
| rm->rm_col[VDEV_RAIDZ_Q].rc_abd = |
| abd_alloc_linear(rm->rm_col[VDEV_RAIDZ_Q].rc_size, B_TRUE); |
| rm->rm_col[x].rc_size = 0; |
| rm->rm_col[y].rc_size = 0; |
| |
| vdev_raidz_generate_parity_pq(rm); |
| |
| rm->rm_col[x].rc_size = xsize; |
| rm->rm_col[y].rc_size = ysize; |
| |
| p = abd_to_buf(pdata); |
| q = abd_to_buf(qdata); |
| pxy = abd_to_buf(rm->rm_col[VDEV_RAIDZ_P].rc_abd); |
| qxy = abd_to_buf(rm->rm_col[VDEV_RAIDZ_Q].rc_abd); |
| xd = rm->rm_col[x].rc_abd; |
| yd = rm->rm_col[y].rc_abd; |
| |
| /* |
| * We now have: |
| * Pxy = P + D_x + D_y |
| * Qxy = Q + 2^(ndevs - 1 - x) * D_x + 2^(ndevs - 1 - y) * D_y |
| * |
| * We can then solve for D_x: |
| * D_x = A * (P + Pxy) + B * (Q + Qxy) |
| * where |
| * A = 2^(x - y) * (2^(x - y) + 1)^-1 |
| * B = 2^(ndevs - 1 - x) * (2^(x - y) + 1)^-1 |
| * |
| * With D_x in hand, we can easily solve for D_y: |
| * D_y = P + Pxy + D_x |
| */ |
| |
| a = vdev_raidz_pow2[255 + x - y]; |
| b = vdev_raidz_pow2[255 - (rm->rm_cols - 1 - x)]; |
| tmp = 255 - vdev_raidz_log2[a ^ 1]; |
| |
| aexp = vdev_raidz_log2[vdev_raidz_exp2(a, tmp)]; |
| bexp = vdev_raidz_log2[vdev_raidz_exp2(b, tmp)]; |
| |
| ASSERT3U(xsize, >=, ysize); |
| struct reconst_pq_struct rpq = { p, q, pxy, qxy, aexp, bexp }; |
| |
| (void) abd_iterate_func2(xd, yd, 0, 0, ysize, |
| vdev_raidz_reconst_pq_func, &rpq); |
| (void) abd_iterate_func(xd, ysize, xsize - ysize, |
| vdev_raidz_reconst_pq_tail_func, &rpq); |
| |
| abd_free(rm->rm_col[VDEV_RAIDZ_P].rc_abd); |
| abd_free(rm->rm_col[VDEV_RAIDZ_Q].rc_abd); |
| |
| /* |
| * Restore the saved parity data. |
| */ |
| rm->rm_col[VDEV_RAIDZ_P].rc_abd = pdata; |
| rm->rm_col[VDEV_RAIDZ_Q].rc_abd = qdata; |
| |
| return ((1 << VDEV_RAIDZ_P) | (1 << VDEV_RAIDZ_Q)); |
| } |
| |
| /* BEGIN CSTYLED */ |
| /* |
| * In the general case of reconstruction, we must solve the system of linear |
| * equations defined by the coeffecients used to generate parity as well as |
| * the contents of the data and parity disks. This can be expressed with |
| * vectors for the original data (D) and the actual data (d) and parity (p) |
| * and a matrix composed of the identity matrix (I) and a dispersal matrix (V): |
| * |
| * __ __ __ __ |
| * | | __ __ | p_0 | |
| * | V | | D_0 | | p_m-1 | |
| * | | x | : | = | d_0 | |
| * | I | | D_n-1 | | : | |
| * | | ~~ ~~ | d_n-1 | |
| * ~~ ~~ ~~ ~~ |
| * |
| * I is simply a square identity matrix of size n, and V is a vandermonde |
| * matrix defined by the coeffecients we chose for the various parity columns |
| * (1, 2, 4). Note that these values were chosen both for simplicity, speedy |
| * computation as well as linear separability. |
| * |
| * __ __ __ __ |
| * | 1 .. 1 1 1 | | p_0 | |
| * | 2^n-1 .. 4 2 1 | __ __ | : | |
| * | 4^n-1 .. 16 4 1 | | D_0 | | p_m-1 | |
| * | 1 .. 0 0 0 | | D_1 | | d_0 | |
| * | 0 .. 0 0 0 | x | D_2 | = | d_1 | |
| * | : : : : | | : | | d_2 | |
| * | 0 .. 1 0 0 | | D_n-1 | | : | |
| * | 0 .. 0 1 0 | ~~ ~~ | : | |
| * | 0 .. 0 0 1 | | d_n-1 | |
| * ~~ ~~ ~~ ~~ |
| * |
| * Note that I, V, d, and p are known. To compute D, we must invert the |
| * matrix and use the known data and parity values to reconstruct the unknown |
| * data values. We begin by removing the rows in V|I and d|p that correspond |
| * to failed or missing columns; we then make V|I square (n x n) and d|p |
| * sized n by removing rows corresponding to unused parity from the bottom up |
| * to generate (V|I)' and (d|p)'. We can then generate the inverse of (V|I)' |
| * using Gauss-Jordan elimination. In the example below we use m=3 parity |
| * columns, n=8 data columns, with errors in d_1, d_2, and p_1: |
| * __ __ |
| * | 1 1 1 1 1 1 1 1 | |
| * | 128 64 32 16 8 4 2 1 | <-----+-+-- missing disks |
| * | 19 205 116 29 64 16 4 1 | / / |
| * | 1 0 0 0 0 0 0 0 | / / |
| * | 0 1 0 0 0 0 0 0 | <--' / |
| * (V|I) = | 0 0 1 0 0 0 0 0 | <---' |
| * | 0 0 0 1 0 0 0 0 | |
| * | 0 0 0 0 1 0 0 0 | |
| * | 0 0 0 0 0 1 0 0 | |
| * | 0 0 0 0 0 0 1 0 | |
| * | 0 0 0 0 0 0 0 1 | |
| * ~~ ~~ |
| * __ __ |
| * | 1 1 1 1 1 1 1 1 | |
| * | 128 64 32 16 8 4 2 1 | |
| * | 19 205 116 29 64 16 4 1 | |
| * | 1 0 0 0 0 0 0 0 | |
| * | 0 1 0 0 0 0 0 0 | |
| * (V|I)' = | 0 0 1 0 0 0 0 0 | |
| * | 0 0 0 1 0 0 0 0 | |
| * | 0 0 0 0 1 0 0 0 | |
| * | 0 0 0 0 0 1 0 0 | |
| * | 0 0 0 0 0 0 1 0 | |
| * | 0 0 0 0 0 0 0 1 | |
| * ~~ ~~ |
| * |
| * Here we employ Gauss-Jordan elimination to find the inverse of (V|I)'. We |
| * have carefully chosen the seed values 1, 2, and 4 to ensure that this |
| * matrix is not singular. |
| * __ __ |
| * | 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 | |
| * | 19 205 116 29 64 16 4 1 0 1 0 0 0 0 0 0 | |
| * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | |
| * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | |
| * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | |
| * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | |
| * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | |
| * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | |
| * ~~ ~~ |
| * __ __ |
| * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | |
| * | 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 | |
| * | 19 205 116 29 64 16 4 1 0 1 0 0 0 0 0 0 | |
| * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | |
| * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | |
| * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | |
| * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | |
| * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | |
| * ~~ ~~ |
| * __ __ |
| * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | |
| * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 | |
| * | 0 205 116 0 0 0 0 0 0 1 19 29 64 16 4 1 | |
| * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | |
| * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | |
| * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | |
| * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | |
| * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | |
| * ~~ ~~ |
| * __ __ |
| * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | |
| * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 | |
| * | 0 0 185 0 0 0 0 0 205 1 222 208 141 221 201 204 | |
| * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | |
| * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | |
| * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | |
| * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | |
| * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | |
| * ~~ ~~ |
| * __ __ |
| * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | |
| * | 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 | |
| * | 0 0 1 0 0 0 0 0 166 100 4 40 158 168 216 209 | |
| * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | |
| * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | |
| * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | |
| * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | |
| * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | |
| * ~~ ~~ |
| * __ __ |
| * | 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 | |
| * | 0 1 0 0 0 0 0 0 167 100 5 41 159 169 217 208 | |
| * | 0 0 1 0 0 0 0 0 166 100 4 40 158 168 216 209 | |
| * | 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 | |
| * | 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 | |
| * | 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 | |
| * | 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 | |
| * | 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 | |
| * ~~ ~~ |
| * __ __ |
| * | 0 0 1 0 0 0 0 0 | |
| * | 167 100 5 41 159 169 217 208 | |
| * | 166 100 4 40 158 168 216 209 | |
| * (V|I)'^-1 = | 0 0 0 1 0 0 0 0 | |
| * | 0 0 0 0 1 0 0 0 | |
| * | 0 0 0 0 0 1 0 0 | |
| * | 0 0 0 0 0 0 1 0 | |
| * | 0 0 0 0 0 0 0 1 | |
| * ~~ ~~ |
| * |
| * We can then simply compute D = (V|I)'^-1 x (d|p)' to discover the values |
| * of the missing data. |
| * |
| * As is apparent from the example above, the only non-trivial rows in the |
| * inverse matrix correspond to the data disks that we're trying to |
| * reconstruct. Indeed, those are the only rows we need as the others would |
| * only be useful for reconstructing data known or assumed to be valid. For |
| * that reason, we only build the coefficients in the rows that correspond to |
| * targeted columns. |
| */ |
| /* END CSTYLED */ |
| |
| static void |
| vdev_raidz_matrix_init(raidz_map_t *rm, int n, int nmap, int *map, |
| uint8_t **rows) |
| { |
| int i, j; |
| int pow; |
| |
| ASSERT(n == rm->rm_cols - rm->rm_firstdatacol); |
| |
| /* |
| * Fill in the missing rows of interest. |
| */ |
| for (i = 0; i < nmap; i++) { |
| ASSERT3S(0, <=, map[i]); |
| ASSERT3S(map[i], <=, 2); |
| |
| pow = map[i] * n; |
| if (pow > 255) |
| pow -= 255; |
| ASSERT(pow <= 255); |
| |
| for (j = 0; j < n; j++) { |
| pow -= map[i]; |
| if (pow < 0) |
| pow += 255; |
| rows[i][j] = vdev_raidz_pow2[pow]; |
| } |
| } |
| } |
| |
| static void |
| vdev_raidz_matrix_invert(raidz_map_t *rm, int n, int nmissing, int *missing, |
| uint8_t **rows, uint8_t **invrows, const uint8_t *used) |
| { |
| int i, j, ii, jj; |
| uint8_t log; |
| |
| /* |
| * Assert that the first nmissing entries from the array of used |
| * columns correspond to parity columns and that subsequent entries |
| * correspond to data columns. |
| */ |
| for (i = 0; i < nmissing; i++) { |
| ASSERT3S(used[i], <, rm->rm_firstdatacol); |
| } |
| for (; i < n; i++) { |
| ASSERT3S(used[i], >=, rm->rm_firstdatacol); |
| } |
| |
| /* |
| * First initialize the storage where we'll compute the inverse rows. |
| */ |
| for (i = 0; i < nmissing; i++) { |
| for (j = 0; j < n; j++) { |
| invrows[i][j] = (i == j) ? 1 : 0; |
| } |
| } |
| |
| /* |
| * Subtract all trivial rows from the rows of consequence. |
| */ |
| for (i = 0; i < nmissing; i++) { |
| for (j = nmissing; j < n; j++) { |
| ASSERT3U(used[j], >=, rm->rm_firstdatacol); |
| jj = used[j] - rm->rm_firstdatacol; |
| ASSERT3S(jj, <, n); |
| invrows[i][j] = rows[i][jj]; |
| rows[i][jj] = 0; |
| } |
| } |
| |
| /* |
| * For each of the rows of interest, we must normalize it and subtract |
| * a multiple of it from the other rows. |
| */ |
| for (i = 0; i < nmissing; i++) { |
| for (j = 0; j < missing[i]; j++) { |
| ASSERT0(rows[i][j]); |
| } |
| ASSERT3U(rows[i][missing[i]], !=, 0); |
| |
| /* |
| * Compute the inverse of the first element and multiply each |
| * element in the row by that value. |
| */ |
| log = 255 - vdev_raidz_log2[rows[i][missing[i]]]; |
| |
| for (j = 0; j < n; j++) { |
| rows[i][j] = vdev_raidz_exp2(rows[i][j], log); |
| invrows[i][j] = vdev_raidz_exp2(invrows[i][j], log); |
| } |
| |
| for (ii = 0; ii < nmissing; ii++) { |
| if (i == ii) |
| continue; |
| |
| ASSERT3U(rows[ii][missing[i]], !=, 0); |
| |
| log = vdev_raidz_log2[rows[ii][missing[i]]]; |
| |
| for (j = 0; j < n; j++) { |
| rows[ii][j] ^= |
| vdev_raidz_exp2(rows[i][j], log); |
| invrows[ii][j] ^= |
| vdev_raidz_exp2(invrows[i][j], log); |
| } |
| } |
| } |
| |
| /* |
| * Verify that the data that is left in the rows are properly part of |
| * an identity matrix. |
| */ |
| for (i = 0; i < nmissing; i++) { |
| for (j = 0; j < n; j++) { |
| if (j == missing[i]) { |
| ASSERT3U(rows[i][j], ==, 1); |
| } else { |
| ASSERT0(rows[i][j]); |
| } |
| } |
| } |
| } |
| |
| static void |
| vdev_raidz_matrix_reconstruct(raidz_map_t *rm, int n, int nmissing, |
| int *missing, uint8_t **invrows, const uint8_t *used) |
| { |
| int i, j, x, cc, c; |
| uint8_t *src; |
| uint64_t ccount; |
| uint8_t *dst[VDEV_RAIDZ_MAXPARITY] = { NULL }; |
| uint64_t dcount[VDEV_RAIDZ_MAXPARITY] = { 0 }; |
| uint8_t log = 0; |
| uint8_t val; |
| int ll; |
| uint8_t *invlog[VDEV_RAIDZ_MAXPARITY]; |
| uint8_t *p, *pp; |
| size_t psize; |
| |
| psize = sizeof (invlog[0][0]) * n * nmissing; |
| p = kmem_alloc(psize, KM_SLEEP); |
| |
| for (pp = p, i = 0; i < nmissing; i++) { |
| invlog[i] = pp; |
| pp += n; |
| } |
| |
| for (i = 0; i < nmissing; i++) { |
| for (j = 0; j < n; j++) { |
| ASSERT3U(invrows[i][j], !=, 0); |
| invlog[i][j] = vdev_raidz_log2[invrows[i][j]]; |
| } |
| } |
| |
| for (i = 0; i < n; i++) { |
| c = used[i]; |
| ASSERT3U(c, <, rm->rm_cols); |
| |
| src = abd_to_buf(rm->rm_col[c].rc_abd); |
| ccount = rm->rm_col[c].rc_size; |
| for (j = 0; j < nmissing; j++) { |
| cc = missing[j] + rm->rm_firstdatacol; |
| ASSERT3U(cc, >=, rm->rm_firstdatacol); |
| ASSERT3U(cc, <, rm->rm_cols); |
| ASSERT3U(cc, !=, c); |
| |
| dst[j] = abd_to_buf(rm->rm_col[cc].rc_abd); |
| dcount[j] = rm->rm_col[cc].rc_size; |
| } |
| |
| ASSERT(ccount >= rm->rm_col[missing[0]].rc_size || i > 0); |
| |
| for (x = 0; x < ccount; x++, src++) { |
| if (*src != 0) |
| log = vdev_raidz_log2[*src]; |
| |
| for (cc = 0; cc < nmissing; cc++) { |
| if (x >= dcount[cc]) |
| continue; |
| |
| if (*src == 0) { |
| val = 0; |
| } else { |
| if ((ll = log + invlog[cc][i]) >= 255) |
| ll -= 255; |
| val = vdev_raidz_pow2[ll]; |
| } |
| |
| if (i == 0) |
| dst[cc][x] = val; |
| else |
| dst[cc][x] ^= val; |
| } |
| } |
| } |
| |
| kmem_free(p, psize); |
| } |
| |
| static int |
| vdev_raidz_reconstruct_general(raidz_map_t *rm, int *tgts, int ntgts) |
| { |
| int n, i, c, t, tt; |
| int nmissing_rows; |
| int missing_rows[VDEV_RAIDZ_MAXPARITY]; |
| int parity_map[VDEV_RAIDZ_MAXPARITY]; |
| |
| uint8_t *p, *pp; |
| size_t psize; |
| |
| uint8_t *rows[VDEV_RAIDZ_MAXPARITY]; |
| uint8_t *invrows[VDEV_RAIDZ_MAXPARITY]; |
| uint8_t *used; |
| |
| abd_t **bufs = NULL; |
| |
| int code = 0; |
| |
| /* |
| * Matrix reconstruction can't use scatter ABDs yet, so we allocate |
| * temporary linear ABDs. |
| */ |
| if (!abd_is_linear(rm->rm_col[rm->rm_firstdatacol].rc_abd)) { |
| bufs = kmem_alloc(rm->rm_cols * sizeof (abd_t *), KM_PUSHPAGE); |
| |
| for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
| raidz_col_t *col = &rm->rm_col[c]; |
| |
| bufs[c] = col->rc_abd; |
| col->rc_abd = abd_alloc_linear(col->rc_size, B_TRUE); |
| abd_copy(col->rc_abd, bufs[c], col->rc_size); |
| } |
| } |
| |
| n = rm->rm_cols - rm->rm_firstdatacol; |
| |
| /* |
| * Figure out which data columns are missing. |
| */ |
| nmissing_rows = 0; |
| for (t = 0; t < ntgts; t++) { |
| if (tgts[t] >= rm->rm_firstdatacol) { |
| missing_rows[nmissing_rows++] = |
| tgts[t] - rm->rm_firstdatacol; |
| } |
| } |
| |
| /* |
| * Figure out which parity columns to use to help generate the missing |
| * data columns. |
| */ |
| for (tt = 0, c = 0, i = 0; i < nmissing_rows; c++) { |
| ASSERT(tt < ntgts); |
| ASSERT(c < rm->rm_firstdatacol); |
| |
| /* |
| * Skip any targeted parity columns. |
| */ |
| if (c == tgts[tt]) { |
| tt++; |
| continue; |
| } |
| |
| code |= 1 << c; |
| |
| parity_map[i] = c; |
| i++; |
| } |
| |
| ASSERT(code != 0); |
| ASSERT3U(code, <, 1 << VDEV_RAIDZ_MAXPARITY); |
| |
| psize = (sizeof (rows[0][0]) + sizeof (invrows[0][0])) * |
| nmissing_rows * n + sizeof (used[0]) * n; |
| p = kmem_alloc(psize, KM_SLEEP); |
| |
| for (pp = p, i = 0; i < nmissing_rows; i++) { |
| rows[i] = pp; |
| pp += n; |
| invrows[i] = pp; |
| pp += n; |
| } |
| used = pp; |
| |
| for (i = 0; i < nmissing_rows; i++) { |
| used[i] = parity_map[i]; |
| } |
| |
| for (tt = 0, c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
| if (tt < nmissing_rows && |
| c == missing_rows[tt] + rm->rm_firstdatacol) { |
| tt++; |
| continue; |
| } |
| |
| ASSERT3S(i, <, n); |
| used[i] = c; |
| i++; |
| } |
| |
| /* |
| * Initialize the interesting rows of the matrix. |
| */ |
| vdev_raidz_matrix_init(rm, n, nmissing_rows, parity_map, rows); |
| |
| /* |
| * Invert the matrix. |
| */ |
| vdev_raidz_matrix_invert(rm, n, nmissing_rows, missing_rows, rows, |
| invrows, used); |
| |
| /* |
| * Reconstruct the missing data using the generated matrix. |
| */ |
| vdev_raidz_matrix_reconstruct(rm, n, nmissing_rows, missing_rows, |
| invrows, used); |
| |
| kmem_free(p, psize); |
| |
| /* |
| * copy back from temporary linear abds and free them |
| */ |
| if (bufs) { |
| for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
| raidz_col_t *col = &rm->rm_col[c]; |
| |
| abd_copy(bufs[c], col->rc_abd, col->rc_size); |
| abd_free(col->rc_abd); |
| col->rc_abd = bufs[c]; |
| } |
| kmem_free(bufs, rm->rm_cols * sizeof (abd_t *)); |
| } |
| |
| return (code); |
| } |
| |
| int |
| vdev_raidz_reconstruct(raidz_map_t *rm, const int *t, int nt) |
| { |
| int tgts[VDEV_RAIDZ_MAXPARITY], *dt; |
| int ntgts; |
| int i, c, ret; |
| int code; |
| int nbadparity, nbaddata; |
| int parity_valid[VDEV_RAIDZ_MAXPARITY]; |
| |
| /* |
| * The tgts list must already be sorted. |
| */ |
| for (i = 1; i < nt; i++) { |
| ASSERT(t[i] > t[i - 1]); |
| } |
| |
| nbadparity = rm->rm_firstdatacol; |
| nbaddata = rm->rm_cols - nbadparity; |
| ntgts = 0; |
| for (i = 0, c = 0; c < rm->rm_cols; c++) { |
| if (c < rm->rm_firstdatacol) |
| parity_valid[c] = B_FALSE; |
| |
| if (i < nt && c == t[i]) { |
| tgts[ntgts++] = c; |
| i++; |
| } else if (rm->rm_col[c].rc_error != 0) { |
| tgts[ntgts++] = c; |
| } else if (c >= rm->rm_firstdatacol) { |
| nbaddata--; |
| } else { |
| parity_valid[c] = B_TRUE; |
| nbadparity--; |
| } |
| } |
| |
| ASSERT(ntgts >= nt); |
| ASSERT(nbaddata >= 0); |
| ASSERT(nbaddata + nbadparity == ntgts); |
| |
| dt = &tgts[nbadparity]; |
| |
| /* Reconstruct using the new math implementation */ |
| ret = vdev_raidz_math_reconstruct(rm, parity_valid, dt, nbaddata); |
| if (ret != RAIDZ_ORIGINAL_IMPL) |
| return (ret); |
| |
| /* |
| * See if we can use any of our optimized reconstruction routines. |
| */ |
| switch (nbaddata) { |
| case 1: |
| if (parity_valid[VDEV_RAIDZ_P]) |
| return (vdev_raidz_reconstruct_p(rm, dt, 1)); |
| |
| ASSERT(rm->rm_firstdatacol > 1); |
| |
| if (parity_valid[VDEV_RAIDZ_Q]) |
| return (vdev_raidz_reconstruct_q(rm, dt, 1)); |
| |
| ASSERT(rm->rm_firstdatacol > 2); |
| break; |
| |
| case 2: |
| ASSERT(rm->rm_firstdatacol > 1); |
| |
| if (parity_valid[VDEV_RAIDZ_P] && |
| parity_valid[VDEV_RAIDZ_Q]) |
| return (vdev_raidz_reconstruct_pq(rm, dt, 2)); |
| |
| ASSERT(rm->rm_firstdatacol > 2); |
| |
| break; |
| } |
| |
| code = vdev_raidz_reconstruct_general(rm, tgts, ntgts); |
| ASSERT(code < (1 << VDEV_RAIDZ_MAXPARITY)); |
| ASSERT(code > 0); |
| return (code); |
| } |
| |
| static int |
| vdev_raidz_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize, |
| uint64_t *ashift) |
| { |
| vdev_t *cvd; |
| uint64_t nparity = vd->vdev_nparity; |
| int c; |
| int lasterror = 0; |
| int numerrors = 0; |
| |
| ASSERT(nparity > 0); |
| |
| if (nparity > VDEV_RAIDZ_MAXPARITY || |
| vd->vdev_children < nparity + 1) { |
| vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL; |
| return (SET_ERROR(EINVAL)); |
| } |
| |
| vdev_open_children(vd); |
| |
| for (c = 0; c < vd->vdev_children; c++) { |
| cvd = vd->vdev_child[c]; |
| |
| if (cvd->vdev_open_error != 0) { |
| lasterror = cvd->vdev_open_error; |
| numerrors++; |
| continue; |
| } |
| |
| *asize = MIN(*asize - 1, cvd->vdev_asize - 1) + 1; |
| *max_asize = MIN(*max_asize - 1, cvd->vdev_max_asize - 1) + 1; |
| *ashift = MAX(*ashift, cvd->vdev_ashift); |
| } |
| |
| *asize *= vd->vdev_children; |
| *max_asize *= vd->vdev_children; |
| |
| if (numerrors > nparity) { |
| vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS; |
| return (lasterror); |
| } |
| |
| return (0); |
| } |
| |
| static void |
| vdev_raidz_close(vdev_t *vd) |
| { |
| int c; |
| |
| for (c = 0; c < vd->vdev_children; c++) |
| vdev_close(vd->vdev_child[c]); |
| } |
| |
| static uint64_t |
| vdev_raidz_asize(vdev_t *vd, uint64_t psize) |
| { |
| uint64_t asize; |
| uint64_t ashift = vd->vdev_top->vdev_ashift; |
| uint64_t cols = vd->vdev_children; |
| uint64_t nparity = vd->vdev_nparity; |
| |
| asize = ((psize - 1) >> ashift) + 1; |
| asize += nparity * ((asize + cols - nparity - 1) / (cols - nparity)); |
| asize = roundup(asize, nparity + 1) << ashift; |
| |
| return (asize); |
| } |
| |
| static void |
| vdev_raidz_child_done(zio_t *zio) |
| { |
| raidz_col_t *rc = zio->io_private; |
| |
| rc->rc_error = zio->io_error; |
| rc->rc_tried = 1; |
| rc->rc_skipped = 0; |
| } |
| |
| static void |
| vdev_raidz_io_verify(zio_t *zio, raidz_map_t *rm, int col) |
| { |
| #ifdef ZFS_DEBUG |
| vdev_t *vd = zio->io_vd; |
| vdev_t *tvd = vd->vdev_top; |
| |
| range_seg_t logical_rs, physical_rs; |
| logical_rs.rs_start = zio->io_offset; |
| logical_rs.rs_end = logical_rs.rs_start + |
| vdev_raidz_asize(zio->io_vd, zio->io_size); |
| |
| raidz_col_t *rc = &rm->rm_col[col]; |
| vdev_t *cvd = vd->vdev_child[rc->rc_devidx]; |
| |
| vdev_xlate(cvd, &logical_rs, &physical_rs); |
| ASSERT3U(rc->rc_offset, ==, physical_rs.rs_start); |
| ASSERT3U(rc->rc_offset, <, physical_rs.rs_end); |
| /* |
| * It would be nice to assert that rs_end is equal |
| * to rc_offset + rc_size but there might be an |
| * optional I/O at the end that is not accounted in |
| * rc_size. |
| */ |
| if (physical_rs.rs_end > rc->rc_offset + rc->rc_size) { |
| ASSERT3U(physical_rs.rs_end, ==, rc->rc_offset + |
| rc->rc_size + (1 << tvd->vdev_ashift)); |
| } else { |
| ASSERT3U(physical_rs.rs_end, ==, rc->rc_offset + rc->rc_size); |
| } |
| #endif |
| } |
| |
| /* |
| * Start an IO operation on a RAIDZ VDev |
| * |
| * Outline: |
| * - For write operations: |
| * 1. Generate the parity data |
| * 2. Create child zio write operations to each column's vdev, for both |
| * data and parity. |
| * 3. If the column skips any sectors for padding, create optional dummy |
| * write zio children for those areas to improve aggregation continuity. |
| * - For read operations: |
| * 1. Create child zio read operations to each data column's vdev to read |
| * the range of data required for zio. |
| * 2. If this is a scrub or resilver operation, or if any of the data |
| * vdevs have had errors, then create zio read operations to the parity |
| * columns' VDevs as well. |
| */ |
| static void |
| vdev_raidz_io_start(zio_t *zio) |
| { |
| vdev_t *vd = zio->io_vd; |
| vdev_t *tvd = vd->vdev_top; |
| vdev_t *cvd; |
| raidz_map_t *rm; |
| raidz_col_t *rc; |
| int c, i; |
| |
| rm = vdev_raidz_map_alloc(zio, tvd->vdev_ashift, vd->vdev_children, |
| vd->vdev_nparity); |
| |
| ASSERT3U(rm->rm_asize, ==, vdev_psize_to_asize(vd, zio->io_size)); |
| |
| if (zio->io_type == ZIO_TYPE_WRITE) { |
| vdev_raidz_generate_parity(rm); |
| |
| for (c = 0; c < rm->rm_cols; c++) { |
| rc = &rm->rm_col[c]; |
| cvd = vd->vdev_child[rc->rc_devidx]; |
| |
| /* |
| * Verify physical to logical translation. |
| */ |
| vdev_raidz_io_verify(zio, rm, c); |
| |
| zio_nowait(zio_vdev_child_io(zio, NULL, cvd, |
| rc->rc_offset, rc->rc_abd, rc->rc_size, |
| zio->io_type, zio->io_priority, 0, |
| vdev_raidz_child_done, rc)); |
| } |
| |
| /* |
| * Generate optional I/Os for any skipped sectors to improve |
| * aggregation contiguity. |
| */ |
| for (c = rm->rm_skipstart, i = 0; i < rm->rm_nskip; c++, i++) { |
| ASSERT(c <= rm->rm_scols); |
| if (c == rm->rm_scols) |
| c = 0; |
| rc = &rm->rm_col[c]; |
| cvd = vd->vdev_child[rc->rc_devidx]; |
| zio_nowait(zio_vdev_child_io(zio, NULL, cvd, |
| rc->rc_offset + rc->rc_size, NULL, |
| 1 << tvd->vdev_ashift, |
| zio->io_type, zio->io_priority, |
| ZIO_FLAG_NODATA | ZIO_FLAG_OPTIONAL, NULL, NULL)); |
| } |
| |
| zio_execute(zio); |
| return; |
| } |
| |
| ASSERT(zio->io_type == ZIO_TYPE_READ); |
| |
| /* |
| * Iterate over the columns in reverse order so that we hit the parity |
| * last -- any errors along the way will force us to read the parity. |
| */ |
| for (c = rm->rm_cols - 1; c >= 0; c--) { |
| rc = &rm->rm_col[c]; |
| cvd = vd->vdev_child[rc->rc_devidx]; |
| if (!vdev_readable(cvd)) { |
| if (c >= rm->rm_firstdatacol) |
| rm->rm_missingdata++; |
| else |
| rm->rm_missingparity++; |
| rc->rc_error = SET_ERROR(ENXIO); |
| rc->rc_tried = 1; /* don't even try */ |
| rc->rc_skipped = 1; |
| continue; |
| } |
| if (vdev_dtl_contains(cvd, DTL_MISSING, zio->io_txg, 1)) { |
| if (c >= rm->rm_firstdatacol) |
| rm->rm_missingdata++; |
| else |
| rm->rm_missingparity++; |
| rc->rc_error = SET_ERROR(ESTALE); |
| rc->rc_skipped = 1; |
| continue; |
| } |
| if (c >= rm->rm_firstdatacol || rm->rm_missingdata > 0 || |
| (zio->io_flags & (ZIO_FLAG_SCRUB | ZIO_FLAG_RESILVER))) { |
| zio_nowait(zio_vdev_child_io(zio, NULL, cvd, |
| rc->rc_offset, rc->rc_abd, rc->rc_size, |
| zio->io_type, zio->io_priority, 0, |
| vdev_raidz_child_done, rc)); |
| } |
| } |
| |
| zio_execute(zio); |
| } |
| |
| |
| /* |
| * Report a checksum error for a child of a RAID-Z device. |
| */ |
| static void |
| raidz_checksum_error(zio_t *zio, raidz_col_t *rc, abd_t *bad_data) |
| { |
| vdev_t *vd = zio->io_vd->vdev_child[rc->rc_devidx]; |
| |
| if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) { |
| zio_bad_cksum_t zbc; |
| raidz_map_t *rm = zio->io_vsd; |
| |
| mutex_enter(&vd->vdev_stat_lock); |
| vd->vdev_stat.vs_checksum_errors++; |
| mutex_exit(&vd->vdev_stat_lock); |
| |
| zbc.zbc_has_cksum = 0; |
| zbc.zbc_injected = rm->rm_ecksuminjected; |
| |
| zfs_ereport_post_checksum(zio->io_spa, vd, |
| &zio->io_bookmark, zio, rc->rc_offset, rc->rc_size, |
| rc->rc_abd, bad_data, &zbc); |
| } |
| } |
| |
| /* |
| * We keep track of whether or not there were any injected errors, so that |
| * any ereports we generate can note it. |
| */ |
| static int |
| raidz_checksum_verify(zio_t *zio) |
| { |
| zio_bad_cksum_t zbc; |
| raidz_map_t *rm = zio->io_vsd; |
| |
| bzero(&zbc, sizeof (zio_bad_cksum_t)); |
| |
| int ret = zio_checksum_error(zio, &zbc); |
| if (ret != 0 && zbc.zbc_injected != 0) |
| rm->rm_ecksuminjected = 1; |
| |
| return (ret); |
| } |
| |
| /* |
| * Generate the parity from the data columns. If we tried and were able to |
| * read the parity without error, verify that the generated parity matches the |
| * data we read. If it doesn't, we fire off a checksum error. Return the |
| * number such failures. |
| */ |
| static int |
| raidz_parity_verify(zio_t *zio, raidz_map_t *rm) |
| { |
| abd_t *orig[VDEV_RAIDZ_MAXPARITY]; |
| int c, ret = 0; |
| raidz_col_t *rc; |
| |
| blkptr_t *bp = zio->io_bp; |
| enum zio_checksum checksum = (bp == NULL ? zio->io_prop.zp_checksum : |
| (BP_IS_GANG(bp) ? ZIO_CHECKSUM_GANG_HEADER : BP_GET_CHECKSUM(bp))); |
| |
| if (checksum == ZIO_CHECKSUM_NOPARITY) |
| return (ret); |
| |
| for (c = 0; c < rm->rm_firstdatacol; c++) { |
| rc = &rm->rm_col[c]; |
| if (!rc->rc_tried || rc->rc_error != 0) |
| continue; |
| |
| orig[c] = abd_alloc_sametype(rc->rc_abd, rc->rc_size); |
| abd_copy(orig[c], rc->rc_abd, rc->rc_size); |
| } |
| |
| vdev_raidz_generate_parity(rm); |
| |
| for (c = 0; c < rm->rm_firstdatacol; c++) { |
| rc = &rm->rm_col[c]; |
| if (!rc->rc_tried || rc->rc_error != 0) |
| continue; |
| if (abd_cmp(orig[c], rc->rc_abd) != 0) { |
| raidz_checksum_error(zio, rc, orig[c]); |
| rc->rc_error = SET_ERROR(ECKSUM); |
| ret++; |
| } |
| abd_free(orig[c]); |
| } |
| |
| return (ret); |
| } |
| |
| static int |
| vdev_raidz_worst_error(raidz_map_t *rm) |
| { |
| int error = 0; |
| |
| for (int c = 0; c < rm->rm_cols; c++) |
| error = zio_worst_error(error, rm->rm_col[c].rc_error); |
| |
| return (error); |
| } |
| |
| /* |
| * Iterate over all combinations of bad data and attempt a reconstruction. |
| * Note that the algorithm below is non-optimal because it doesn't take into |
| * account how reconstruction is actually performed. For example, with |
| * triple-parity RAID-Z the reconstruction procedure is the same if column 4 |
| * is targeted as invalid as if columns 1 and 4 are targeted since in both |
| * cases we'd only use parity information in column 0. |
| */ |
| static int |
| vdev_raidz_combrec(zio_t *zio, int total_errors, int data_errors) |
| { |
| raidz_map_t *rm = zio->io_vsd; |
| raidz_col_t *rc; |
| abd_t *orig[VDEV_RAIDZ_MAXPARITY]; |
| int tstore[VDEV_RAIDZ_MAXPARITY + 2]; |
| int *tgts = &tstore[1]; |
| int curr, next, i, c, n; |
| int code, ret = 0; |
| |
| ASSERT(total_errors < rm->rm_firstdatacol); |
| |
| /* |
| * This simplifies one edge condition. |
| */ |
| tgts[-1] = -1; |
| |
| for (n = 1; n <= rm->rm_firstdatacol - total_errors; n++) { |
| /* |
| * Initialize the targets array by finding the first n columns |
| * that contain no error. |
| * |
| * If there were no data errors, we need to ensure that we're |
| * always explicitly attempting to reconstruct at least one |
| * data column. To do this, we simply push the highest target |
| * up into the data columns. |
| */ |
| for (c = 0, i = 0; i < n; i++) { |
| if (i == n - 1 && data_errors == 0 && |
| c < rm->rm_firstdatacol) { |
| c = rm->rm_firstdatacol; |
| } |
| |
| while (rm->rm_col[c].rc_error != 0) { |
| c++; |
| ASSERT3S(c, <, rm->rm_cols); |
| } |
| |
| tgts[i] = c++; |
| } |
| |
| /* |
| * Setting tgts[n] simplifies the other edge condition. |
| */ |
| tgts[n] = rm->rm_cols; |
| |
| /* |
| * These buffers were allocated in previous iterations. |
| */ |
| for (i = 0; i < n - 1; i++) { |
| ASSERT(orig[i] != NULL); |
| } |
| |
| orig[n - 1] = abd_alloc_sametype(rm->rm_col[0].rc_abd, |
| rm->rm_col[0].rc_size); |
| |
| curr = 0; |
| next = tgts[curr]; |
| |
| while (curr != n) { |
| tgts[curr] = next; |
| curr = 0; |
| |
| /* |
| * Save off the original data that we're going to |
| * attempt to reconstruct. |
| */ |
| for (i = 0; i < n; i++) { |
| ASSERT(orig[i] != NULL); |
| c = tgts[i]; |
| ASSERT3S(c, >=, 0); |
| ASSERT3S(c, <, rm->rm_cols); |
| rc = &rm->rm_col[c]; |
| abd_copy(orig[i], rc->rc_abd, rc->rc_size); |
| } |
| |
| /* |
| * Attempt a reconstruction and exit the outer loop on |
| * success. |
| */ |
| code = vdev_raidz_reconstruct(rm, tgts, n); |
| if (raidz_checksum_verify(zio) == 0) { |
| |
| for (i = 0; i < n; i++) { |
| c = tgts[i]; |
| rc = &rm->rm_col[c]; |
| ASSERT(rc->rc_error == 0); |
| if (rc->rc_tried) |
| raidz_checksum_error(zio, rc, |
| orig[i]); |
| rc->rc_error = SET_ERROR(ECKSUM); |
| } |
| |
| ret = code; |
| goto done; |
| } |
| |
| /* |
| * Restore the original data. |
| */ |
| for (i = 0; i < n; i++) { |
| c = tgts[i]; |
| rc = &rm->rm_col[c]; |
| abd_copy(rc->rc_abd, orig[i], rc->rc_size); |
| } |
| |
| do { |
| /* |
| * Find the next valid column after the curr |
| * position.. |
| */ |
| for (next = tgts[curr] + 1; |
| next < rm->rm_cols && |
| rm->rm_col[next].rc_error != 0; next++) |
| continue; |
| |
| ASSERT(next <= tgts[curr + 1]); |
| |
| /* |
| * If that spot is available, we're done here. |
| */ |
| if (next != tgts[curr + 1]) |
| break; |
| |
| /* |
| * Otherwise, find the next valid column after |
| * the previous position. |
| */ |
| for (c = tgts[curr - 1] + 1; |
| rm->rm_col[c].rc_error != 0; c++) |
| continue; |
| |
| tgts[curr] = c; |
| curr++; |
| |
| } while (curr != n); |
| } |
| } |
| n--; |
| done: |
| for (i = 0; i < n; i++) |
| abd_free(orig[i]); |
| |
| return (ret); |
| } |
| |
| /* |
| * Complete an IO operation on a RAIDZ VDev |
| * |
| * Outline: |
| * - For write operations: |
| * 1. Check for errors on the child IOs. |
| * 2. Return, setting an error code if too few child VDevs were written |
| * to reconstruct the data later. Note that partial writes are |
| * considered successful if they can be reconstructed at all. |
| * - For read operations: |
| * 1. Check for errors on the child IOs. |
| * 2. If data errors occurred: |
| * a. Try to reassemble the data from the parity available. |
| * b. If we haven't yet read the parity drives, read them now. |
| * c. If all parity drives have been read but the data still doesn't |
| * reassemble with a correct checksum, then try combinatorial |
| * reconstruction. |
| * d. If that doesn't work, return an error. |
| * 3. If there were unexpected errors or this is a resilver operation, |
| * rewrite the vdevs that had errors. |
| */ |
| static void |
| vdev_raidz_io_done(zio_t *zio) |
| { |
| vdev_t *vd = zio->io_vd; |
| vdev_t *cvd; |
| raidz_map_t *rm = zio->io_vsd; |
| raidz_col_t *rc = NULL; |
| int unexpected_errors = 0; |
| int parity_errors = 0; |
| int parity_untried = 0; |
| int data_errors = 0; |
| int total_errors = 0; |
| int n, c; |
| int tgts[VDEV_RAIDZ_MAXPARITY]; |
| int code; |
| |
| ASSERT(zio->io_bp != NULL); /* XXX need to add code to enforce this */ |
| |
| ASSERT(rm->rm_missingparity <= rm->rm_firstdatacol); |
| ASSERT(rm->rm_missingdata <= rm->rm_cols - rm->rm_firstdatacol); |
| |
| for (c = 0; c < rm->rm_cols; c++) { |
| rc = &rm->rm_col[c]; |
| |
| if (rc->rc_error) { |
| ASSERT(rc->rc_error != ECKSUM); /* child has no bp */ |
| |
| if (c < rm->rm_firstdatacol) |
| parity_errors++; |
| else |
| data_errors++; |
| |
| if (!rc->rc_skipped) |
| unexpected_errors++; |
| |
| total_errors++; |
| } else if (c < rm->rm_firstdatacol && !rc->rc_tried) { |
| parity_untried++; |
| } |
| } |
| |
| if (zio->io_type == ZIO_TYPE_WRITE) { |
| /* |
| * XXX -- for now, treat partial writes as a success. |
| * (If we couldn't write enough columns to reconstruct |
| * the data, the I/O failed. Otherwise, good enough.) |
| * |
| * Now that we support write reallocation, it would be better |
| * to treat partial failure as real failure unless there are |
| * no non-degraded top-level vdevs left, and not update DTLs |
| * if we intend to reallocate. |
| */ |
| /* XXPOLICY */ |
| if (total_errors > rm->rm_firstdatacol) |
| zio->io_error = vdev_raidz_worst_error(rm); |
| |
| return; |
| } |
| |
| ASSERT(zio->io_type == ZIO_TYPE_READ); |
| /* |
| * There are three potential phases for a read: |
| * 1. produce valid data from the columns read |
| * 2. read all disks and try again |
| * 3. perform combinatorial reconstruction |
| * |
| * Each phase is progressively both more expensive and less likely to |
| * occur. If we encounter more errors than we can repair or all phases |
| * fail, we have no choice but to return an error. |
| */ |
| |
| /* |
| * If the number of errors we saw was correctable -- less than or equal |
| * to the number of parity disks read -- attempt to produce data that |
| * has a valid checksum. Naturally, this case applies in the absence of |
| * any errors. |
| */ |
| if (total_errors <= rm->rm_firstdatacol - parity_untried) { |
| if (data_errors == 0) { |
| if (raidz_checksum_verify(zio) == 0) { |
| /* |
| * If we read parity information (unnecessarily |
| * as it happens since no reconstruction was |
| * needed) regenerate and verify the parity. |
| * We also regenerate parity when resilvering |
| * so we can write it out to the failed device |
| * later. |
| */ |
| if (parity_errors + parity_untried < |
| rm->rm_firstdatacol || |
| (zio->io_flags & ZIO_FLAG_RESILVER)) { |
| n = raidz_parity_verify(zio, rm); |
| unexpected_errors += n; |
| ASSERT(parity_errors + n <= |
| rm->rm_firstdatacol); |
| } |
| goto done; |
| } |
| } else { |
| /* |
| * We either attempt to read all the parity columns or |
| * none of them. If we didn't try to read parity, we |
| * wouldn't be here in the correctable case. There must |
| * also have been fewer parity errors than parity |
| * columns or, again, we wouldn't be in this code path. |
| */ |
| ASSERT(parity_untried == 0); |
| ASSERT(parity_errors < rm->rm_firstdatacol); |
| |
| /* |
| * Identify the data columns that reported an error. |
| */ |
| n = 0; |
| for (c = rm->rm_firstdatacol; c < rm->rm_cols; c++) { |
| rc = &rm->rm_col[c]; |
| if (rc->rc_error != 0) { |
| ASSERT(n < VDEV_RAIDZ_MAXPARITY); |
| tgts[n++] = c; |
| } |
| } |
| |
| ASSERT(rm->rm_firstdatacol >= n); |
| |
| code = vdev_raidz_reconstruct(rm, tgts, n); |
| |
| if (raidz_checksum_verify(zio) == 0) { |
| /* |
| * If we read more parity disks than were used |
| * for reconstruction, confirm that the other |
| * parity disks produced correct data. This |
| * routine is suboptimal in that it regenerates |
| * the parity that we already used in addition |
| * to the parity that we're attempting to |
| * verify, but this should be a relatively |
| * uncommon case, and can be optimized if it |
| * becomes a problem. Note that we regenerate |
| * parity when resilvering so we can write it |
| * out to failed devices later. |
| */ |
| if (parity_errors < rm->rm_firstdatacol - n || |
| (zio->io_flags & ZIO_FLAG_RESILVER)) { |
| n = raidz_parity_verify(zio, rm); |
| unexpected_errors += n; |
| ASSERT(parity_errors + n <= |
| rm->rm_firstdatacol); |
| } |
| |
| goto done; |
| } |
| } |
| } |
| |
| /* |
| * This isn't a typical situation -- either we got a read error or |
| * a child silently returned bad data. Read every block so we can |
| * try again with as much data and parity as we can track down. If |
| * we've already been through once before, all children will be marked |
| * as tried so we'll proceed to combinatorial reconstruction. |
| */ |
| unexpected_errors = 1; |
| rm->rm_missingdata = 0; |
| rm->rm_missingparity = 0; |
| |
| for (c = 0; c < rm->rm_cols; c++) { |
| if (rm->rm_col[c].rc_tried) |
| continue; |
| |
| zio_vdev_io_redone(zio); |
| do { |
| rc = &rm->rm_col[c]; |
| if (rc->rc_tried) |
| continue; |
| zio_nowait(zio_vdev_child_io(zio, NULL, |
| vd->vdev_child[rc->rc_devidx], |
| rc->rc_offset, rc->rc_abd, rc->rc_size, |
| zio->io_type, zio->io_priority, 0, |
| vdev_raidz_child_done, rc)); |
| } while (++c < rm->rm_cols); |
| |
| return; |
| } |
| |
| /* |
| * At this point we've attempted to reconstruct the data given the |
| * errors we detected, and we've attempted to read all columns. There |
| * must, therefore, be one or more additional problems -- silent errors |
| * resulting in invalid data rather than explicit I/O errors resulting |
| * in absent data. We check if there is enough additional data to |
| * possibly reconstruct the data and then perform combinatorial |
| * reconstruction over all possible combinations. If that fails, |
| * we're cooked. |
| */ |
| if (total_errors > rm->rm_firstdatacol) { |
| zio->io_error = vdev_raidz_worst_error(rm); |
| |
| } else if (total_errors < rm->rm_firstdatacol && |
| (code = vdev_raidz_combrec(zio, total_errors, data_errors)) != 0) { |
| /* |
| * If we didn't use all the available parity for the |
| * combinatorial reconstruction, verify that the remaining |
| * parity is correct. |
| */ |
| if (code != (1 << rm->rm_firstdatacol) - 1) |
| (void) raidz_parity_verify(zio, rm); |
| } else { |
| /* |
| * We're here because either: |
| * |
| * total_errors == rm_first_datacol, or |
| * vdev_raidz_combrec() failed |
| * |
| * In either case, there is enough bad data to prevent |
| * reconstruction. |
| * |
| * Start checksum ereports for all children which haven't |
| * failed, and the IO wasn't speculative. |
| */ |
| zio->io_error = SET_ERROR(ECKSUM); |
| |
| if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) { |
| for (c = 0; c < rm->rm_cols; c++) { |
| vdev_t *cvd; |
| rc = &rm->rm_col[c]; |
| cvd = vd->vdev_child[rc->rc_devidx]; |
| if (rc->rc_error == 0) { |
| zio_bad_cksum_t zbc; |
| zbc.zbc_has_cksum = 0; |
| zbc.zbc_injected = |
| rm->rm_ecksuminjected; |
| |
| mutex_enter(&cvd->vdev_stat_lock); |
| cvd->vdev_stat.vs_checksum_errors++; |
| mutex_exit(&cvd->vdev_stat_lock); |
| |
| zfs_ereport_start_checksum( |
| zio->io_spa, cvd, |
| &zio->io_bookmark, zio, |
| rc->rc_offset, rc->rc_size, |
| (void *)(uintptr_t)c, &zbc); |
| } |
| } |
| } |
| } |
| |
| done: |
| zio_checksum_verified(zio); |
| |
| if (zio->io_error == 0 && spa_writeable(zio->io_spa) && |
| (unexpected_errors || (zio->io_flags & ZIO_FLAG_RESILVER))) { |
| /* |
| * Use the good data we have in hand to repair damaged children. |
| */ |
| for (c = 0; c < rm->rm_cols; c++) { |
| rc = &rm->rm_col[c]; |
| cvd = vd->vdev_child[rc->rc_devidx]; |
| |
| if (rc->rc_error == 0) |
| continue; |
| |
| zio_nowait(zio_vdev_child_io(zio, NULL, cvd, |
| rc->rc_offset, rc->rc_abd, rc->rc_size, |
| ZIO_TYPE_WRITE, ZIO_PRIORITY_ASYNC_WRITE, |
| ZIO_FLAG_IO_REPAIR | (unexpected_errors ? |
| ZIO_FLAG_SELF_HEAL : 0), NULL, NULL)); |
| } |
| } |
| } |
| |
| static void |
| vdev_raidz_state_change(vdev_t *vd, int faulted, int degraded) |
| { |
| if (faulted > vd->vdev_nparity) |
| vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN, |
| VDEV_AUX_NO_REPLICAS); |
| else if (degraded + faulted != 0) |
| vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE); |
| else |
| vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE); |
| } |
| |
| /* |
| * Determine if any portion of the provided block resides on a child vdev |
| * with a dirty DTL and therefore needs to be resilvered. The function |
| * assumes that at least one DTL is dirty which implies that full stripe |
| * width blocks must be resilvered. |
| */ |
| static boolean_t |
| vdev_raidz_need_resilver(vdev_t *vd, uint64_t offset, size_t psize) |
| { |
| uint64_t dcols = vd->vdev_children; |
| uint64_t nparity = vd->vdev_nparity; |
| uint64_t ashift = vd->vdev_top->vdev_ashift; |
| /* The starting RAIDZ (parent) vdev sector of the block. */ |
| uint64_t b = offset >> ashift; |
| /* The zio's size in units of the vdev's minimum sector size. */ |
| uint64_t s = ((psize - 1) >> ashift) + 1; |
| /* The first column for this stripe. */ |
| uint64_t f = b % dcols; |
| |
| if (s + nparity >= dcols) |
| return (B_TRUE); |
| |
| for (uint64_t c = 0; c < s + nparity; c++) { |
| uint64_t devidx = (f + c) % dcols; |
| vdev_t *cvd = vd->vdev_child[devidx]; |
| |
| /* |
| * dsl_scan_need_resilver() already checked vd with |
| * vdev_dtl_contains(). So here just check cvd with |
| * vdev_dtl_empty(), cheaper and a good approximation. |
| */ |
| if (!vdev_dtl_empty(cvd, DTL_PARTIAL)) |
| return (B_TRUE); |
| } |
| |
| return (B_FALSE); |
| } |
| |
| static void |
| vdev_raidz_xlate(vdev_t *cvd, const range_seg_t *in, range_seg_t *res) |
| { |
| vdev_t *raidvd = cvd->vdev_parent; |
| ASSERT(raidvd->vdev_ops == &vdev_raidz_ops); |
| |
| uint64_t width = raidvd->vdev_children; |
| uint64_t tgt_col = cvd->vdev_id; |
| uint64_t ashift = raidvd->vdev_top->vdev_ashift; |
| |
| /* make sure the offsets are block-aligned */ |
| ASSERT0(in->rs_start % (1 << ashift)); |
| ASSERT0(in->rs_end % (1 << ashift)); |
| uint64_t b_start = in->rs_start >> ashift; |
| uint64_t b_end = in->rs_end >> ashift; |
| |
| uint64_t start_row = 0; |
| if (b_start > tgt_col) /* avoid underflow */ |
| start_row = ((b_start - tgt_col - 1) / width) + 1; |
| |
| uint64_t end_row = 0; |
| if (b_end > tgt_col) |
| end_row = ((b_end - tgt_col - 1) / width) + 1; |
| |
| res->rs_start = start_row << ashift; |
| res->rs_end = end_row << ashift; |
| |
| ASSERT3U(res->rs_start, <=, in->rs_start); |
| ASSERT3U(res->rs_end - res->rs_start, <=, in->rs_end - in->rs_start); |
| } |
| |
| vdev_ops_t vdev_raidz_ops = { |
| .vdev_op_open = vdev_raidz_open, |
| .vdev_op_close = vdev_raidz_close, |
| .vdev_op_asize = vdev_raidz_asize, |
| .vdev_op_io_start = vdev_raidz_io_start, |
| .vdev_op_io_done = vdev_raidz_io_done, |
| .vdev_op_state_change = vdev_raidz_state_change, |
| .vdev_op_need_resilver = vdev_raidz_need_resilver, |
| .vdev_op_hold = NULL, |
| .vdev_op_rele = NULL, |
| .vdev_op_remap = NULL, |
| .vdev_op_xlate = vdev_raidz_xlate, |
| .vdev_op_type = VDEV_TYPE_RAIDZ, /* name of this vdev type */ |
| .vdev_op_leaf = B_FALSE /* not a leaf vdev */ |
| }; |