Implement an IO manager that uses a gigantic mmap of the disk device.
This enables us to experiment with multithreaded metadata prefetch,
where we spawn a bunch of threads to issue a massive amount of IO to
fault in metadata.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
e2fsck/unix.c | 7 +
lib/ext2fs/Makefile.in | 8 +
lib/ext2fs/ext2_io.h | 3
lib/ext2fs/mmap_io.c | 534 ++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 551 insertions(+), 1 deletion(-)
create mode 100644 lib/ext2fs/mmap_io.c
diff --git a/e2fsck/unix.c b/e2fsck/unix.c
index 67d7384..eeeef7c 100644
--- a/e2fsck/unix.c
+++ b/e2fsck/unix.c
@@ -1255,7 +1255,12 @@ restart:
test_io_backing_manager = unix_io_manager;
} else
#endif
- io_ptr = unix_io_manager;
+ {
+ if (getenv("TEST_MMAP_IO"))
+ io_ptr = mmap_io_manager;
+ else
+ io_ptr = unix_io_manager;
+ }
flags |= EXT2_FLAG_NOFREE_ON_ERROR;
profile_get_boolean(ctx->profile, "options", "old_bitmaps", 0, 0,
&old_bitmaps);
diff --git a/lib/ext2fs/Makefile.in b/lib/ext2fs/Makefile.in
index 29d3527..a1b5a01 100644
--- a/lib/ext2fs/Makefile.in
+++ b/lib/ext2fs/Makefile.in
@@ -67,6 +67,7 @@ OBJS= $(DEBUGFS_LIB_OBJS) $(RESIZE_LIB_OBJS) $(E2IMAGE_LIB_OBJS) \
lookup.o \
mkdir.o \
mkjournal.o \
+ mmap_io.o \
mmp.o \
namei.o \
native.o \
@@ -143,6 +144,7 @@ SRCS= ext2_err.c \
$(srcdir)/lookup.c \
$(srcdir)/mkdir.c \
$(srcdir)/mkjournal.c \
+ $(srcdir)/mmap_io.c \
$(srcdir)/mmp.c \
$(srcdir)/namei.c \
$(srcdir)/native.c \
@@ -825,6 +827,12 @@ mkjournal.o: $(srcdir)/mkjournal.c $(top_builddir)/lib/config.h \
$(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/ext2_ext_attr.h \
$(srcdir)/bitops.h $(srcdir)/jfs_user.h $(srcdir)/kernel-jbd.h \
$(srcdir)/jfs_compat.h $(srcdir)/kernel-list.h
+mmap_io.o: $(srcdir)/mmap_io.c $(top_builddir)/lib/config.h \
+ $(top_builddir)/lib/dirpaths.h $(srcdir)/ext2_fs.h \
+ $(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
+ $(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h \
+ $(srcdir)/ext2_io.h $(top_builddir)/lib/ext2fs/ext2_err.h \
+ $(srcdir)/ext2_ext_attr.h $(srcdir)/bitops.h
mmp.o: $(srcdir)/mmp.c $(top_builddir)/lib/config.h \
$(top_builddir)/lib/dirpaths.h $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
diff --git a/lib/ext2fs/ext2_io.h b/lib/ext2fs/ext2_io.h
index 1894fb8..39e0594 100644
--- a/lib/ext2fs/ext2_io.h
+++ b/lib/ext2fs/ext2_io.h
@@ -125,6 +125,9 @@ extern errcode_t io_channel_discard(io_channel channel,
extern errcode_t io_channel_alloc_buf(io_channel channel,
int count, void *ptr);
+/* mmap_io.c */
+extern io_manager mmap_io_manager;
+
/* unix_io.c */
extern io_manager unix_io_manager;
diff --git a/lib/ext2fs/mmap_io.c b/lib/ext2fs/mmap_io.c
new file mode 100644
index 0000000..37ca18b
--- /dev/null
+++ b/lib/ext2fs/mmap_io.c
@@ -0,0 +1,534 @@
+/*
+ * mmap_io.c --- This is the mmap implementation of the I/O manager.
+ *
+ * Copyright (C) 2014 by Oracle, Darrick J. Wong.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
+ * %End-Header%
+ */
+
+#define _LARGEFILE_SOURCE
+#define _LARGEFILE64_SOURCE
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#if HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#include <fcntl.h>
+#include <time.h>
+#ifdef __linux__
+#include <sys/utsname.h>
+#endif
+#ifdef HAVE_SYS_IOCTL_H
+#include <sys/ioctl.h>
+#endif
+#ifdef HAVE_SYS_MOUNT_H
+#include <sys/mount.h>
+#endif
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#if HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif
+#if HAVE_LINUX_FALLOC_H
+#include <linux/falloc.h>
+#endif
+#include <sys/mman.h>
+#include <stdint.h>
+
+#if defined(__linux__) && defined(_IO) && !defined(BLKROGET)
+#define BLKROGET _IO(0x12, 94) /* Get read-only status (0 = read_write). */
+#endif
+
+#undef ALIGN_DEBUG
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+/*
+ * For checking structure magic numbers...
+ */
+
+#define EXT2_CHECK_MAGIC(struct, code) \
+ if ((struct)->magic != (code)) return (code)
+
+struct mmap_private_data {
+ int magic;
+ int dev;
+ int flags;
+ int access_time;
+ ext2_loff_t offset;
+ void *bounce;
+ struct struct_io_stats io_stats;
+ void *map;
+ blk64_t length;
+};
+
+static errcode_t mmap_open(const char *name, int flags, io_channel *channel);
+static errcode_t mmap_close(io_channel channel);
+static errcode_t mmap_set_blksize(io_channel channel, int blksize);
+static errcode_t mmap_read_blk(io_channel channel, unsigned long block,
+ int count, void *data);
+static errcode_t mmap_write_blk(io_channel channel, unsigned long block,
+ int count, const void *data);
+static errcode_t mmap_flush(io_channel channel);
+static errcode_t mmap_write_byte(io_channel channel, unsigned long offset,
+ int size, const void *data);
+static errcode_t mmap_set_option(io_channel channel, const char *option,
+ const char *arg);
+static errcode_t mmap_get_stats(io_channel channel, io_stats *stats)
+;
+static errcode_t mmap_read_blk64(io_channel channel, unsigned long long block,
+ int count, void *data);
+static errcode_t mmap_write_blk64(io_channel channel, unsigned long long block,
+ int count, const void *data);
+static errcode_t mmap_discard(io_channel channel, unsigned long long block,
+ unsigned long long count);
+
+static struct struct_io_manager struct_mmap_manager = {
+ EXT2_ET_MAGIC_IO_MANAGER,
+ "MMAP I/O Manager",
+ mmap_open,
+ mmap_close,
+ mmap_set_blksize,
+ mmap_read_blk,
+ mmap_write_blk,
+ mmap_flush,
+ mmap_write_byte,
+ mmap_set_option,
+ mmap_get_stats,
+ mmap_read_blk64,
+ mmap_write_blk64,
+ mmap_discard,
+};
+
+io_manager mmap_io_manager = &struct_mmap_manager;
+
+static errcode_t mmap_get_stats(io_channel channel, io_stats *stats)
+{
+ errcode_t retval = 0;
+
+ struct mmap_private_data *data;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct mmap_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (stats)
+ *stats = &data->io_stats;
+
+ return retval;
+}
+
+/*
+ * Here are the raw I/O functions
+ */
+static errcode_t raw_read_blk(io_channel channel,
+ struct mmap_private_data *data,
+ unsigned long long block,
+ int count, void *bufv)
+{
+ ssize_t size;
+ ext2_loff_t location;
+ int actual = 0;
+ unsigned char *buf = bufv;
+
+ size = (count < 0) ? -count : count * channel->block_size;
+ data->io_stats.bytes_read += size;
+ location = ((ext2_loff_t) block * channel->block_size) + data->offset;
+ memcpy(buf, data->map + location, size);
+
+ return 0;
+}
+
+static errcode_t raw_write_blk(io_channel channel,
+ struct mmap_private_data *data,
+ unsigned long long block,
+ int count, const void *bufv)
+{
+ ssize_t size;
+ ext2_loff_t location;
+ int actual = 0;
+ const unsigned char *buf = bufv;
+
+ size = (count < 0) ? -count : count * channel->block_size;
+ data->io_stats.bytes_written += size;
+ location = ((ext2_loff_t) block * channel->block_size) + data->offset;
+ memcpy(data->map + location, buf, size);
+
+ return 0;
+}
+
+#ifdef __linux__
+#ifndef BLKDISCARDZEROES
+#define BLKDISCARDZEROES _IO(0x12, 124)
+#endif
+#endif
+
+static errcode_t mmap_open(const char *name, int flags, io_channel *channel)
+{
+ io_channel io = NULL;
+ struct mmap_private_data *data = NULL;
+ errcode_t retval;
+ int open_flags;
+ int f_nocache = 0;
+ ext2fs_struct_stat st;
+#ifdef __linux__
+ struct utsname ut;
+#endif
+
+ if (name == 0)
+ return EXT2_ET_BAD_DEVICE_NAME;
+ retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
+ if (retval)
+ goto cleanup;
+ memset(io, 0, sizeof(struct struct_io_channel));
+ io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
+ retval = ext2fs_get_mem(sizeof(struct mmap_private_data), &data);
+ if (retval)
+ goto cleanup;
+
+ io->manager = mmap_io_manager;
+ retval = ext2fs_get_mem(strlen(name)+1, &io->name);
+ if (retval)
+ goto cleanup;
+
+ strcpy(io->name, name);
+ io->private_data = data;
+ io->block_size = 1024;
+ io->read_error = 0;
+ io->write_error = 0;
+ io->refcount = 1;
+
+ memset(data, 0, sizeof(struct mmap_private_data));
+ data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL;
+ data->io_stats.num_fields = 2;
+ data->dev = -1;
+
+ open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY;
+ if (flags & IO_FLAG_EXCLUSIVE)
+ open_flags |= O_EXCL;
+#if defined(O_DIRECT)
+ if (flags & IO_FLAG_DIRECT_IO)
+ open_flags |= O_DIRECT;
+#elif defined(F_NOCACHE)
+ if (flags & IO_FLAG_DIRECT_IO)
+ f_nocache = F_NOCACHE;
+#endif
+ data->flags = flags;
+
+ data->dev = ext2fs_open_file(io->name, open_flags, 0);
+ if (data->dev < 0) {
+ retval = errno;
+ goto cleanup;
+ }
+ if (f_nocache) {
+ if (fcntl(data->dev, f_nocache, 1) < 0) {
+ retval = errno;
+ goto cleanup;
+ }
+ }
+
+ /*
+ * If the device is really a block device, then set the
+ * appropriate flag, otherwise we can set DISCARD_ZEROES flag
+ * because we are going to use punch hole instead of discard
+ * and if it succeed, subsequent read from sparse area returns
+ * zero.
+ */
+ if (ext2fs_stat(io->name, &st) == 0) {
+ if (S_ISBLK(st.st_mode))
+ io->flags |= CHANNEL_FLAGS_BLOCK_DEVICE;
+ else
+ io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES;
+ }
+
+#ifdef BLKDISCARDZEROES
+ {
+ int zeroes = 0;
+ if (ioctl(data->dev, BLKDISCARDZEROES, &zeroes) == 0 &&
+ zeroes)
+ io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES;
+ }
+#endif
+
+#ifdef BLKROGET
+ if (flags & IO_FLAG_RW) {
+ int error;
+ int readonly = 0;
+
+ /* Is the block device actually writable? */
+ error = ioctl(data->dev, BLKROGET, &readonly);
+ if (!error && readonly) {
+ retval = EPERM;
+ goto cleanup;
+ }
+ }
+#endif
+
+ retval = ext2fs_get_device_size2(name, 1024, &data->length);
+ if (retval)
+ goto cleanup;
+ if (data->length == 0) {
+ retval = EINVAL;
+ goto cleanup;
+ }
+ data->length *= 1024;
+ data->map = mmap(NULL, data->length,
+ PROT_READ | (flags & IO_FLAG_RW ? PROT_WRITE : 0),
+ MAP_SHARED, data->dev, 0);
+ if (data->map == MAP_FAILED) {
+ retval = errno;
+ goto cleanup;
+ }
+
+#ifdef __linux__
+#undef RLIM_INFINITY
+#if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4)))
+#define RLIM_INFINITY ((unsigned long)(~0UL>>1))
+#else
+#define RLIM_INFINITY (~0UL)
+#endif
+ /*
+ * Work around a bug in 2.4.10-2.4.18 kernels where writes to
+ * block devices are wrongly getting hit by the filesize
+ * limit. This workaround isn't perfect, since it won't work
+ * if glibc wasn't built against 2.2 header files. (Sigh.)
+ *
+ */
+ if ((flags & IO_FLAG_RW) &&
+ (uname(&ut) == 0) &&
+ ((ut.release[0] == '2') && (ut.release[1] == '.') &&
+ (ut.release[2] == '4') && (ut.release[3] == '.') &&
+ (ut.release[4] == '1') && (ut.release[5] >= '0') &&
+ (ut.release[5] < '8')) &&
+ (ext2fs_stat(io->name, &st) == 0) &&
+ (S_ISBLK(st.st_mode))) {
+ struct rlimit rlim;
+
+ rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY;
+ setrlimit(RLIMIT_FSIZE, &rlim);
+ getrlimit(RLIMIT_FSIZE, &rlim);
+ if (((unsigned long) rlim.rlim_cur) <
+ ((unsigned long) rlim.rlim_max)) {
+ rlim.rlim_cur = rlim.rlim_max;
+ setrlimit(RLIMIT_FSIZE, &rlim);
+ }
+ }
+#endif
+ *channel = io;
+ return 0;
+
+cleanup:
+ if (data) {
+ if (data->dev >= 0)
+ close(data->dev);
+ ext2fs_free_mem(&data);
+ }
+ if (io) {
+ if (io->name)
+ ext2fs_free_mem(&io->name);
+ ext2fs_free_mem(&io);
+ }
+ return retval;
+}
+
+static errcode_t mmap_close(io_channel channel)
+{
+ struct mmap_private_data *data;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct mmap_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (--channel->refcount > 0)
+ return 0;
+
+ munmap(data->map, data->length);
+
+ if (close(data->dev) < 0)
+ retval = errno;
+
+ ext2fs_free_mem(&channel->private_data);
+ if (channel->name)
+ ext2fs_free_mem(&channel->name);
+ ext2fs_free_mem(&channel);
+ return retval;
+}
+
+static errcode_t mmap_set_blksize(io_channel channel, int blksize)
+{
+ struct mmap_private_data *data;
+ errcode_t retval;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct mmap_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ channel->block_size = blksize;
+ return 0;
+}
+
+
+static errcode_t mmap_read_blk64(io_channel channel, unsigned long long block,
+ int count, void *buf)
+{
+ struct mmap_private_data *data;
+ errcode_t retval;
+ char *cp;
+ int i, j;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct mmap_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ return raw_read_blk(channel, data, block, count, buf);
+}
+
+static errcode_t mmap_read_blk(io_channel channel, unsigned long block,
+ int count, void *buf)
+{
+ return mmap_read_blk64(channel, block, count, buf);
+}
+
+static errcode_t mmap_write_blk64(io_channel channel, unsigned long long block,
+ int count, const void *buf)
+{
+ struct mmap_private_data *data;
+ errcode_t retval = 0;
+ const char *cp;
+ int writethrough;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct mmap_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ return raw_write_blk(channel, data, block, count, buf);
+}
+
+static errcode_t mmap_write_blk(io_channel channel, unsigned long block,
+ int count, const void *buf)
+{
+ return mmap_write_blk64(channel, block, count, buf);
+}
+
+static errcode_t mmap_write_byte(io_channel channel, unsigned long offset,
+ int size, const void *buf)
+{
+ struct mmap_private_data *data;
+ errcode_t retval = 0;
+ ssize_t actual;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct mmap_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ memcpy(data->map + offset + data->offset, buf, size);
+ return 0;
+}
+
+/*
+ * Flush data buffers to disk.
+ */
+static errcode_t mmap_flush(io_channel channel)
+{
+ struct mmap_private_data *data;
+ errcode_t retval = 0;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct mmap_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ fsync(data->dev);
+ return retval;
+}
+
+static errcode_t mmap_set_option(io_channel channel, const char *option,
+ const char *arg)
+{
+ struct mmap_private_data *data;
+ unsigned long long tmp;
+ char *end;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct mmap_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (!strcmp(option, "offset")) {
+ if (!arg)
+ return EXT2_ET_INVALID_ARGUMENT;
+
+ tmp = strtoull(arg, &end, 0);
+ if (*end)
+ return EXT2_ET_INVALID_ARGUMENT;
+ data->offset = tmp;
+ if (data->offset < 0)
+ return EXT2_ET_INVALID_ARGUMENT;
+ return 0;
+ }
+ return EXT2_ET_INVALID_ARGUMENT;
+}
+
+#if defined(__linux__) && !defined(BLKDISCARD)
+#define BLKDISCARD _IO(0x12, 119)
+#endif
+
+static errcode_t mmap_discard(io_channel channel, unsigned long long block,
+ unsigned long long count)
+{
+ struct mmap_private_data *data;
+ int ret;
+
+ EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+ data = (struct mmap_private_data *) channel->private_data;
+ EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+ if (channel->flags & CHANNEL_FLAGS_BLOCK_DEVICE) {
+#ifdef BLKDISCARD
+ __uint64_t range[2];
+
+ range[0] = (__uint64_t)(block) * channel->block_size;
+ range[1] = (__uint64_t)(count) * channel->block_size;
+
+ ret = ioctl(data->dev, BLKDISCARD, &range);
+#else
+ goto unimplemented;
+#endif
+ } else {
+#if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_PUNCH_HOLE)
+ /*
+ * If we are not on block device, try to use punch hole
+ * to reclaim free space.
+ */
+ ret = fallocate(data->dev,
+ FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ (off_t)(block) * channel->block_size,
+ (off_t)(count) * channel->block_size);
+#else
+ goto unimplemented;
+#endif
+ }
+ if (ret < 0) {
+ if (errno == EOPNOTSUPP)
+ goto unimplemented;
+ return errno;
+ }
+ return 0;
+unimplemented:
+ return EXT2_ET_UNIMPLEMENTED;
+}
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