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/*-
* Copyright (c) 2014-2015 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
/*
* __wt_read --
* Read a chunk.
*/
int
__wt_read(
WT_SESSION_IMPL *session, WT_FH *fh, wt_off_t offset, size_t len, void *buf)
{
size_t chunk;
ssize_t nr;
uint8_t *addr;
WT_STAT_FAST_CONN_INCR(session, read_io);
WT_RET(__wt_verbose(session, WT_VERB_FILEOPS,
"%s: read %" WT_SIZET_FMT " bytes at offset %" PRIuMAX,
fh->name, len, (uintmax_t)offset));
/* Assert direct I/O is aligned and a multiple of the alignment. */
WT_ASSERT(session,
!fh->direct_io ||
S2C(session)->buffer_alignment == 0 ||
(!((uintptr_t)buf &
(uintptr_t)(S2C(session)->buffer_alignment - 1)) &&
len >= S2C(session)->buffer_alignment &&
len % S2C(session)->buffer_alignment == 0));
/* Break reads larger than 1GB into 1GB chunks. */
for (addr = buf; len > 0; addr += nr, len -= (size_t)nr, offset += nr) {
chunk = WT_MIN(len, WT_GIGABYTE);
if ((nr = pread(fh->fd, addr, chunk, offset)) <= 0)
WT_RET_MSG(session, nr == 0 ? WT_ERROR : __wt_errno(),
"%s read error: failed to read %" WT_SIZET_FMT
" bytes at offset %" PRIuMAX,
fh->name, chunk, (uintmax_t)offset);
}
return (0);
}
/*
* __wt_write --
* Write a chunk.
*/
int
__wt_write(WT_SESSION_IMPL *session,
WT_FH *fh, wt_off_t offset, size_t len, const void *buf)
{
size_t chunk;
ssize_t nw;
const uint8_t *addr;
WT_STAT_FAST_CONN_INCR(session, write_io);
WT_RET(__wt_verbose(session, WT_VERB_FILEOPS,
"%s: write %" WT_SIZET_FMT " bytes at offset %" PRIuMAX,
fh->name, len, (uintmax_t)offset));
/* Assert direct I/O is aligned and a multiple of the alignment. */
WT_ASSERT(session,
!fh->direct_io ||
S2C(session)->buffer_alignment == 0 ||
(!((uintptr_t)buf &
(uintptr_t)(S2C(session)->buffer_alignment - 1)) &&
len >= S2C(session)->buffer_alignment &&
len % S2C(session)->buffer_alignment == 0));
/* Break writes larger than 1GB into 1GB chunks. */
for (addr = buf; len > 0; addr += nw, len -= (size_t)nw, offset += nw) {
chunk = WT_MIN(len, WT_GIGABYTE);
if ((nw = pwrite(fh->fd, addr, chunk, offset)) < 0)
WT_RET_MSG(session, __wt_errno(),
"%s write error: failed to write %" WT_SIZET_FMT
" bytes at offset %" PRIuMAX,
fh->name, chunk, (uintmax_t)offset);
}
return (0);
}
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