From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Manage the scheduling, issuance, and reporting of data block
verification reads. This enables us to combine adjacent (or nearly
adjacent) read requests, and to take advantage of high-IOPS devices by
issuing IO from multiple threads.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
scrub/Makefile | 2
scrub/read_verify.c | 268 +++++++++++++++++++++++++++++++++++++++++++++++++++
scrub/read_verify.h | 50 ++++++++++
scrub/xfs_scrub.h | 3 +
4 files changed, 323 insertions(+)
create mode 100644 scrub/read_verify.c
create mode 100644 scrub/read_verify.h
diff --git a/scrub/Makefile b/scrub/Makefile
index a9aaa99..3b3eb95 100644
--- a/scrub/Makefile
+++ b/scrub/Makefile
@@ -23,6 +23,7 @@ disk.h \
filemap.h \
fscounters.h \
inodes.h \
+read_verify.h \
scrub.h \
spacemap.h \
unicrash.h \
@@ -40,6 +41,7 @@ phase1.c \
phase2.c \
phase3.c \
phase5.c \
+read_verify.c \
scrub.c \
spacemap.c \
xfs_scrub.c
diff --git a/scrub/read_verify.c b/scrub/read_verify.c
new file mode 100644
index 0000000..244626d
--- /dev/null
+++ b/scrub/read_verify.c
@@ -0,0 +1,268 @@
+/*
+ * Copyright (C) 2018 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <sys/statvfs.h>
+#include "workqueue.h"
+#include "path.h"
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_scrub.h"
+#include "common.h"
+#include "counter.h"
+#include "disk.h"
+#include "read_verify.h"
+
+/*
+ * Read Verify Pool
+ *
+ * Manages the data block read verification phase. The caller schedules
+ * verification requests, which are then scheduled to be run by a thread
+ * pool worker. Adjacent (or nearly adjacent) requests can be combined
+ * to reduce overhead when free space fragmentation is high. The thread
+ * pool takes care of issuing multiple IOs to the device, if possible.
+ */
+
+/*
+ * Perform all IO in 32M chunks. This cannot exceed 65536 sectors
+ * because that's the biggest SCSI VERIFY(16) we dare to send.
+ */
+#define RVP_IO_MAX_SIZE (33554432)
+#define RVP_IO_MAX_SECTORS (RVP_IO_MAX_SIZE >> BBSHIFT)
+
+/* Tolerate 64k holes in adjacent read verify requests. */
+#define RVP_IO_BATCH_LOCALITY (65536)
+
+struct read_verify_pool {
+ struct workqueue wq; /* thread pool */
+ struct scrub_ctx *ctx; /* scrub context */
+ void *readbuf; /* read buffer */
+ struct ptcounter *verified_bytes;
+ read_verify_ioerr_fn_t ioerr_fn; /* io error callback */
+ size_t miniosz; /* minimum io size, bytes */
+};
+
+/* Create a thread pool to run read verifiers. */
+struct read_verify_pool *
+read_verify_pool_init(
+ struct scrub_ctx *ctx,
+ size_t miniosz,
+ read_verify_ioerr_fn_t ioerr_fn,
+ unsigned int nproc)
+{
+ struct read_verify_pool *rvp;
+ bool ret;
+ int error;
+
+ rvp = calloc(1, sizeof(struct read_verify_pool));
+ if (!rvp)
+ return NULL;
+
+ error = posix_memalign((void **)&rvp->readbuf, page_size,
+ RVP_IO_MAX_SIZE);
+ if (error || !rvp->readbuf)
+ goto out_free;
+ rvp->verified_bytes = ptcounter_init(nproc);
+ if (!rvp->verified_bytes)
+ goto out_buf;
+ rvp->miniosz = miniosz;
+ rvp->ctx = ctx;
+ rvp->ioerr_fn = ioerr_fn;
+ /* Run in the main thread if we only want one thread. */
+ if (nproc == 1)
+ nproc = 0;
+ ret = workqueue_create(&rvp->wq, (struct xfs_mount *)rvp, nproc);
+ if (ret)
+ goto out_counter;
+ return rvp;
+
+out_counter:
+ ptcounter_free(rvp->verified_bytes);
+out_buf:
+ free(rvp->readbuf);
+out_free:
+ free(rvp);
+ return NULL;
+}
+
+/* Finish up any read verification work. */
+void
+read_verify_pool_flush(
+ struct read_verify_pool *rvp)
+{
+ workqueue_destroy(&rvp->wq);
+}
+
+/* Finish up any read verification work and tear it down. */
+void
+read_verify_pool_destroy(
+ struct read_verify_pool *rvp)
+{
+ ptcounter_free(rvp->verified_bytes);
+ free(rvp->readbuf);
+ free(rvp);
+}
+
+/*
+ * Issue a read-verify IO in big batches.
+ */
+static void
+read_verify(
+ struct workqueue *wq,
+ xfs_agnumber_t agno,
+ void *arg)
+{
+ struct read_verify *rv = arg;
+ struct read_verify_pool *rvp;
+ unsigned long long verified = 0;
+ ssize_t sz;
+ ssize_t len;
+
+ rvp = (struct read_verify_pool *)wq->wq_ctx;
+ while (rv->io_length > 0) {
+ len = min(rv->io_length, RVP_IO_MAX_SIZE);
+ dbg_printf("diskverify %d %"PRIu64" %zu\n", rv->io_disk->d_fd,
+ rv->io_start, len);
+ sz = disk_read_verify(rv->io_disk, rvp->readbuf,
+ rv->io_start, len);
+ if (sz < 0) {
+ dbg_printf("IOERR %d %"PRIu64" %zu\n",
+ rv->io_disk->d_fd,
+ rv->io_start, len);
+ /* IO error, so try the next logical block. */
+ len = rvp->miniosz;
+ rvp->ioerr_fn(rvp->ctx, rv->io_disk, rv->io_start, len,
+ errno, rv->io_end_arg);
+ }
+
+ verified += len;
+ rv->io_start += len;
+ rv->io_length -= len;
+ }
+
+ free(rv);
+ ptcounter_add(rvp->verified_bytes, verified);
+}
+
+/* Queue a read verify request. */
+static bool
+read_verify_queue(
+ struct read_verify_pool *rvp,
+ struct read_verify *rv)
+{
+ struct read_verify *tmp;
+ bool ret;
+
+ dbg_printf("verify fd %d start %"PRIu64" len %"PRIu64"\n",
+ rv->io_disk->d_fd, rv->io_start, rv->io_length);
+
+ tmp = malloc(sizeof(struct read_verify));
+ if (!tmp) {
+ rvp->ioerr_fn(rvp->ctx, rv->io_disk, rv->io_start,
+ rv->io_length, errno, rv->io_end_arg);
+ return true;
+ }
+ memcpy(tmp, rv, sizeof(*tmp));
+
+ ret = workqueue_add(&rvp->wq, read_verify, 0, tmp);
+ if (ret) {
+ str_error(rvp->ctx, rvp->ctx->mntpoint,
+_("Could not queue read-verify work."));
+ free(tmp);
+ return false;
+ }
+ rv->io_length = 0;
+ return true;
+}
+
+/*
+ * Issue an IO request. We'll batch subsequent requests if they're
+ * within 64k of each other
+ */
+bool
+read_verify_schedule_io(
+ struct read_verify_pool *rvp,
+ struct read_verify *rv,
+ struct disk *disk,
+ uint64_t start,
+ uint64_t length,
+ void *end_arg)
+{
+ uint64_t req_end;
+ uint64_t rv_end;
+
+ assert(rvp->readbuf);
+ req_end = start + length;
+ rv_end = rv->io_start + rv->io_length;
+
+ /*
+ * If we have a stashed IO, we haven't changed fds, the error
+ * reporting is the same, and the two extents are close,
+ * we can combine them.
+ */
+ if (rv->io_length > 0 && disk == rv->io_disk &&
+ end_arg == rv->io_end_arg &&
+ ((start >= rv->io_start && start <= rv_end + RVP_IO_BATCH_LOCALITY) ||
+ (rv->io_start >= start &&
+ rv->io_start <= req_end + RVP_IO_BATCH_LOCALITY))) {
+ rv->io_start = min(rv->io_start, start);
+ rv->io_length = max(req_end, rv_end) - rv->io_start;
+ } else {
+ /* Otherwise, issue the stashed IO (if there is one) */
+ if (rv->io_length > 0)
+ return read_verify_queue(rvp, rv);
+
+ /* Stash the new IO. */
+ rv->io_disk = disk;
+ rv->io_start = start;
+ rv->io_length = length;
+ rv->io_end_arg = end_arg;
+ }
+
+ return true;
+}
+
+/* Force any stashed IOs into the verifier. */
+bool
+read_verify_force_io(
+ struct read_verify_pool *rvp,
+ struct read_verify *rv)
+{
+ bool moveon;
+
+ assert(rvp->readbuf);
+ if (rv->io_length == 0)
+ return true;
+
+ moveon = read_verify_queue(rvp, rv);
+ if (moveon)
+ rv->io_length = 0;
+ return moveon;
+}
+
+/* How many bytes has this process verified? */
+uint64_t
+read_verify_bytes(
+ struct read_verify_pool *rvp)
+{
+ return ptcounter_value(rvp->verified_bytes);
+}
diff --git a/scrub/read_verify.h b/scrub/read_verify.h
new file mode 100644
index 0000000..cea7a08
--- /dev/null
+++ b/scrub/read_verify.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2018 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#ifndef XFS_SCRUB_READ_VERIFY_H_
+#define XFS_SCRUB_READ_VERIFY_H_
+
+struct scrub_ctx;
+struct read_verify_pool;
+
+/* Function called when an IO error happens. */
+typedef void (*read_verify_ioerr_fn_t)(struct scrub_ctx *ctx,
+ struct disk *disk, uint64_t start, uint64_t length,
+ int error, void *arg);
+
+struct read_verify_pool *read_verify_pool_init(struct scrub_ctx *ctx,
+ size_t miniosz, read_verify_ioerr_fn_t ioerr_fn,
+ unsigned int nproc);
+void read_verify_pool_flush(struct read_verify_pool *rvp);
+void read_verify_pool_destroy(struct read_verify_pool *rvp);
+
+struct read_verify {
+ void *io_end_arg;
+ struct disk *io_disk;
+ uint64_t io_start; /* bytes */
+ uint64_t io_length; /* bytes */
+};
+
+bool read_verify_schedule_io(struct read_verify_pool *rvp,
+ struct read_verify *rv, struct disk *disk, uint64_t start,
+ uint64_t length, void *end_arg);
+bool read_verify_force_io(struct read_verify_pool *rvp, struct read_verify *rv);
+uint64_t read_verify_bytes(struct read_verify_pool *rvp);
+
+#endif /* XFS_SCRUB_READ_VERIFY_H_ */
diff --git a/scrub/xfs_scrub.h b/scrub/xfs_scrub.h
index 66003e4..31a927c 100644
--- a/scrub/xfs_scrub.h
+++ b/scrub/xfs_scrub.h
@@ -83,6 +83,9 @@ struct scrub_ctx {
void *fshandle;
size_t fshandle_len;
+ /* Data block read verification buffer */
+ void *readbuf;
+
/* Mutable scrub state; use lock. */
pthread_mutex_t lock;
unsigned long long max_errors;
--
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