blob: 7e19bbff5f67a7596795b726ac044a040b99c45e [file] [log] [blame]
/*
* Block driver for RAW files (posix)
*
* Copyright (c) 2006 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qapi/error.h"
#include "qemu/cutils.h"
#include "qemu/error-report.h"
#include "block/block_int.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "trace.h"
#include "block/thread-pool.h"
#include "qemu/iov.h"
#include "block/raw-aio.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "scsi/pr-manager.h"
#include "scsi/constants.h"
#if defined(__APPLE__) && (__MACH__)
#include <paths.h>
#include <sys/param.h>
#include <IOKit/IOKitLib.h>
#include <IOKit/IOBSD.h>
#include <IOKit/storage/IOMediaBSDClient.h>
#include <IOKit/storage/IOMedia.h>
#include <IOKit/storage/IOCDMedia.h>
//#include <IOKit/storage/IOCDTypes.h>
#include <IOKit/storage/IODVDMedia.h>
#include <CoreFoundation/CoreFoundation.h>
#endif
#ifdef __sun__
#define _POSIX_PTHREAD_SEMANTICS 1
#include <sys/dkio.h>
#endif
#ifdef __linux__
#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/syscall.h>
#include <linux/cdrom.h>
#include <linux/fd.h>
#include <linux/fs.h>
#include <linux/hdreg.h>
#include <scsi/sg.h>
#ifdef __s390__
#include <asm/dasd.h>
#endif
#ifndef FS_NOCOW_FL
#define FS_NOCOW_FL 0x00800000 /* Do not cow file */
#endif
#endif
#if defined(CONFIG_FALLOCATE_PUNCH_HOLE) || defined(CONFIG_FALLOCATE_ZERO_RANGE)
#include <linux/falloc.h>
#endif
#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
#include <sys/disk.h>
#include <sys/cdio.h>
#endif
#ifdef __OpenBSD__
#include <sys/ioctl.h>
#include <sys/disklabel.h>
#include <sys/dkio.h>
#endif
#ifdef __NetBSD__
#include <sys/ioctl.h>
#include <sys/disklabel.h>
#include <sys/dkio.h>
#include <sys/disk.h>
#endif
#ifdef __DragonFly__
#include <sys/ioctl.h>
#include <sys/diskslice.h>
#endif
#ifdef CONFIG_XFS
#include <xfs/xfs.h>
#endif
#include "trace.h"
/* OS X does not have O_DSYNC */
#ifndef O_DSYNC
#ifdef O_SYNC
#define O_DSYNC O_SYNC
#elif defined(O_FSYNC)
#define O_DSYNC O_FSYNC
#endif
#endif
/* Approximate O_DIRECT with O_DSYNC if O_DIRECT isn't available */
#ifndef O_DIRECT
#define O_DIRECT O_DSYNC
#endif
#define FTYPE_FILE 0
#define FTYPE_CD 1
#define MAX_BLOCKSIZE 4096
/* Posix file locking bytes. Libvirt takes byte 0, we start from higher bytes,
* leaving a few more bytes for its future use. */
#define RAW_LOCK_PERM_BASE 100
#define RAW_LOCK_SHARED_BASE 200
typedef struct BDRVRawState {
int fd;
bool use_lock;
int type;
int open_flags;
size_t buf_align;
/* The current permissions. */
uint64_t perm;
uint64_t shared_perm;
/* The perms bits whose corresponding bytes are already locked in
* s->fd. */
uint64_t locked_perm;
uint64_t locked_shared_perm;
int perm_change_fd;
int perm_change_flags;
BDRVReopenState *reopen_state;
#ifdef CONFIG_XFS
bool is_xfs:1;
#endif
bool has_discard:1;
bool has_write_zeroes:1;
bool discard_zeroes:1;
bool use_linux_aio:1;
bool use_linux_io_uring:1;
bool page_cache_inconsistent:1;
bool has_fallocate;
bool needs_alignment;
bool drop_cache;
bool check_cache_dropped;
struct {
uint64_t discard_nb_ok;
uint64_t discard_nb_failed;
uint64_t discard_bytes_ok;
} stats;
PRManager *pr_mgr;
} BDRVRawState;
typedef struct BDRVRawReopenState {
int fd;
int open_flags;
bool drop_cache;
bool check_cache_dropped;
} BDRVRawReopenState;
static int fd_open(BlockDriverState *bs);
static int64_t raw_getlength(BlockDriverState *bs);
typedef struct RawPosixAIOData {
BlockDriverState *bs;
int aio_type;
int aio_fildes;
off_t aio_offset;
uint64_t aio_nbytes;
union {
struct {
struct iovec *iov;
int niov;
} io;
struct {
uint64_t cmd;
void *buf;
} ioctl;
struct {
int aio_fd2;
off_t aio_offset2;
} copy_range;
struct {
PreallocMode prealloc;
Error **errp;
} truncate;
};
} RawPosixAIOData;
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
static int cdrom_reopen(BlockDriverState *bs);
#endif
#if defined(__NetBSD__)
static int raw_normalize_devicepath(const char **filename, Error **errp)
{
static char namebuf[PATH_MAX];
const char *dp, *fname;
struct stat sb;
fname = *filename;
dp = strrchr(fname, '/');
if (lstat(fname, &sb) < 0) {
error_setg_file_open(errp, errno, fname);
return -errno;
}
if (!S_ISBLK(sb.st_mode)) {
return 0;
}
if (dp == NULL) {
snprintf(namebuf, PATH_MAX, "r%s", fname);
} else {
snprintf(namebuf, PATH_MAX, "%.*s/r%s",
(int)(dp - fname), fname, dp + 1);
}
*filename = namebuf;
warn_report("%s is a block device, using %s", fname, *filename);
return 0;
}
#else
static int raw_normalize_devicepath(const char **filename, Error **errp)
{
return 0;
}
#endif
/*
* Get logical block size via ioctl. On success store it in @sector_size_p.
*/
static int probe_logical_blocksize(int fd, unsigned int *sector_size_p)
{
unsigned int sector_size;
bool success = false;
int i;
errno = ENOTSUP;
static const unsigned long ioctl_list[] = {
#ifdef BLKSSZGET
BLKSSZGET,
#endif
#ifdef DKIOCGETBLOCKSIZE
DKIOCGETBLOCKSIZE,
#endif
#ifdef DIOCGSECTORSIZE
DIOCGSECTORSIZE,
#endif
};
/* Try a few ioctls to get the right size */
for (i = 0; i < (int)ARRAY_SIZE(ioctl_list); i++) {
if (ioctl(fd, ioctl_list[i], &sector_size) >= 0) {
*sector_size_p = sector_size;
success = true;
}
}
return success ? 0 : -errno;
}
/**
* Get physical block size of @fd.
* On success, store it in @blk_size and return 0.
* On failure, return -errno.
*/
static int probe_physical_blocksize(int fd, unsigned int *blk_size)
{
#ifdef BLKPBSZGET
if (ioctl(fd, BLKPBSZGET, blk_size) < 0) {
return -errno;
}
return 0;
#else
return -ENOTSUP;
#endif
}
/* Check if read is allowed with given memory buffer and length.
*
* This function is used to check O_DIRECT memory buffer and request alignment.
*/
static bool raw_is_io_aligned(int fd, void *buf, size_t len)
{
ssize_t ret = pread(fd, buf, len, 0);
if (ret >= 0) {
return true;
}
#ifdef __linux__
/* The Linux kernel returns EINVAL for misaligned O_DIRECT reads. Ignore
* other errors (e.g. real I/O error), which could happen on a failed
* drive, since we only care about probing alignment.
*/
if (errno != EINVAL) {
return true;
}
#endif
return false;
}
static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp)
{
BDRVRawState *s = bs->opaque;
char *buf;
size_t max_align = MAX(MAX_BLOCKSIZE, qemu_real_host_page_size);
size_t alignments[] = {1, 512, 1024, 2048, 4096};
/* For SCSI generic devices the alignment is not really used.
With buffered I/O, we don't have any restrictions. */
if (bdrv_is_sg(bs) || !s->needs_alignment) {
bs->bl.request_alignment = 1;
s->buf_align = 1;
return;
}
bs->bl.request_alignment = 0;
s->buf_align = 0;
/* Let's try to use the logical blocksize for the alignment. */
if (probe_logical_blocksize(fd, &bs->bl.request_alignment) < 0) {
bs->bl.request_alignment = 0;
}
#ifdef CONFIG_XFS
if (s->is_xfs) {
struct dioattr da;
if (xfsctl(NULL, fd, XFS_IOC_DIOINFO, &da) >= 0) {
bs->bl.request_alignment = da.d_miniosz;
/* The kernel returns wrong information for d_mem */
/* s->buf_align = da.d_mem; */
}
}
#endif
/*
* If we could not get the sizes so far, we can only guess them. First try
* to detect request alignment, since it is more likely to succeed. Then
* try to detect buf_align, which cannot be detected in some cases (e.g.
* Gluster). If buf_align cannot be detected, we fallback to the value of
* request_alignment.
*/
if (!bs->bl.request_alignment) {
int i;
size_t align;
buf = qemu_memalign(max_align, max_align);
for (i = 0; i < ARRAY_SIZE(alignments); i++) {
align = alignments[i];
if (raw_is_io_aligned(fd, buf, align)) {
/* Fallback to safe value. */
bs->bl.request_alignment = (align != 1) ? align : max_align;
break;
}
}
qemu_vfree(buf);
}
if (!s->buf_align) {
int i;
size_t align;
buf = qemu_memalign(max_align, 2 * max_align);
for (i = 0; i < ARRAY_SIZE(alignments); i++) {
align = alignments[i];
if (raw_is_io_aligned(fd, buf + align, max_align)) {
/* Fallback to request_alignment. */
s->buf_align = (align != 1) ? align : bs->bl.request_alignment;
break;
}
}
qemu_vfree(buf);
}
if (!s->buf_align || !bs->bl.request_alignment) {
error_setg(errp, "Could not find working O_DIRECT alignment");
error_append_hint(errp, "Try cache.direct=off\n");
}
}
static void raw_parse_flags(int bdrv_flags, int *open_flags, bool has_writers)
{
bool read_write = false;
assert(open_flags != NULL);
*open_flags |= O_BINARY;
*open_flags &= ~O_ACCMODE;
if (bdrv_flags & BDRV_O_AUTO_RDONLY) {
read_write = has_writers;
} else if (bdrv_flags & BDRV_O_RDWR) {
read_write = true;
}
if (read_write) {
*open_flags |= O_RDWR;
} else {
*open_flags |= O_RDONLY;
}
/* Use O_DSYNC for write-through caching, no flags for write-back caching,
* and O_DIRECT for no caching. */
if ((bdrv_flags & BDRV_O_NOCACHE)) {
*open_flags |= O_DIRECT;
}
}
static void raw_parse_filename(const char *filename, QDict *options,
Error **errp)
{
bdrv_parse_filename_strip_prefix(filename, "file:", options);
}
static QemuOptsList raw_runtime_opts = {
.name = "raw",
.head = QTAILQ_HEAD_INITIALIZER(raw_runtime_opts.head),
.desc = {
{
.name = "filename",
.type = QEMU_OPT_STRING,
.help = "File name of the image",
},
{
.name = "aio",
.type = QEMU_OPT_STRING,
.help = "host AIO implementation (threads, native, io_uring)",
},
{
.name = "locking",
.type = QEMU_OPT_STRING,
.help = "file locking mode (on/off/auto, default: auto)",
},
{
.name = "pr-manager",
.type = QEMU_OPT_STRING,
.help = "id of persistent reservation manager object (default: none)",
},
#if defined(__linux__)
{
.name = "drop-cache",
.type = QEMU_OPT_BOOL,
.help = "invalidate page cache during live migration (default: on)",
},
#endif
{
.name = "x-check-cache-dropped",
.type = QEMU_OPT_BOOL,
.help = "check that page cache was dropped on live migration (default: off)"
},
{ /* end of list */ }
},
};
static const char *const mutable_opts[] = { "x-check-cache-dropped", NULL };
static int raw_open_common(BlockDriverState *bs, QDict *options,
int bdrv_flags, int open_flags,
bool device, Error **errp)
{
BDRVRawState *s = bs->opaque;
QemuOpts *opts;
Error *local_err = NULL;
const char *filename = NULL;
const char *str;
BlockdevAioOptions aio, aio_default;
int fd, ret;
struct stat st;
OnOffAuto locking;
opts = qemu_opts_create(&raw_runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
filename = qemu_opt_get(opts, "filename");
ret = raw_normalize_devicepath(&filename, errp);
if (ret != 0) {
goto fail;
}
if (bdrv_flags & BDRV_O_NATIVE_AIO) {
aio_default = BLOCKDEV_AIO_OPTIONS_NATIVE;
#ifdef CONFIG_LINUX_IO_URING
} else if (bdrv_flags & BDRV_O_IO_URING) {
aio_default = BLOCKDEV_AIO_OPTIONS_IO_URING;
#endif
} else {
aio_default = BLOCKDEV_AIO_OPTIONS_THREADS;
}
aio = qapi_enum_parse(&BlockdevAioOptions_lookup,
qemu_opt_get(opts, "aio"),
aio_default, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
s->use_linux_aio = (aio == BLOCKDEV_AIO_OPTIONS_NATIVE);
#ifdef CONFIG_LINUX_IO_URING
s->use_linux_io_uring = (aio == BLOCKDEV_AIO_OPTIONS_IO_URING);
#endif
locking = qapi_enum_parse(&OnOffAuto_lookup,
qemu_opt_get(opts, "locking"),
ON_OFF_AUTO_AUTO, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
switch (locking) {
case ON_OFF_AUTO_ON:
s->use_lock = true;
if (!qemu_has_ofd_lock()) {
warn_report("File lock requested but OFD locking syscall is "
"unavailable, falling back to POSIX file locks");
error_printf("Due to the implementation, locks can be lost "
"unexpectedly.\n");
}
break;
case ON_OFF_AUTO_OFF:
s->use_lock = false;
break;
case ON_OFF_AUTO_AUTO:
s->use_lock = qemu_has_ofd_lock();
break;
default:
abort();
}
str = qemu_opt_get(opts, "pr-manager");
if (str) {
s->pr_mgr = pr_manager_lookup(str, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
}
s->drop_cache = qemu_opt_get_bool(opts, "drop-cache", true);
s->check_cache_dropped = qemu_opt_get_bool(opts, "x-check-cache-dropped",
false);
s->open_flags = open_flags;
raw_parse_flags(bdrv_flags, &s->open_flags, false);
s->fd = -1;
fd = qemu_open(filename, s->open_flags, 0644);
ret = fd < 0 ? -errno : 0;
if (ret < 0) {
error_setg_file_open(errp, -ret, filename);
if (ret == -EROFS) {
ret = -EACCES;
}
goto fail;
}
s->fd = fd;
s->perm = 0;
s->shared_perm = BLK_PERM_ALL;
#ifdef CONFIG_LINUX_AIO
/* Currently Linux does AIO only for files opened with O_DIRECT */
if (s->use_linux_aio) {
if (!(s->open_flags & O_DIRECT)) {
error_setg(errp, "aio=native was specified, but it requires "
"cache.direct=on, which was not specified.");
ret = -EINVAL;
goto fail;
}
if (!aio_setup_linux_aio(bdrv_get_aio_context(bs), errp)) {
error_prepend(errp, "Unable to use native AIO: ");
goto fail;
}
}
#else
if (s->use_linux_aio) {
error_setg(errp, "aio=native was specified, but is not supported "
"in this build.");
ret = -EINVAL;
goto fail;
}
#endif /* !defined(CONFIG_LINUX_AIO) */
#ifdef CONFIG_LINUX_IO_URING
if (s->use_linux_io_uring) {
if (!aio_setup_linux_io_uring(bdrv_get_aio_context(bs), errp)) {
error_prepend(errp, "Unable to use io_uring: ");
goto fail;
}
}
#else
if (s->use_linux_io_uring) {
error_setg(errp, "aio=io_uring was specified, but is not supported "
"in this build.");
ret = -EINVAL;
goto fail;
}
#endif /* !defined(CONFIG_LINUX_IO_URING) */
s->has_discard = true;
s->has_write_zeroes = true;
if ((bs->open_flags & BDRV_O_NOCACHE) != 0) {
s->needs_alignment = true;
}
if (fstat(s->fd, &st) < 0) {
ret = -errno;
error_setg_errno(errp, errno, "Could not stat file");
goto fail;
}
if (!device) {
if (S_ISBLK(st.st_mode)) {
warn_report("Opening a block device as a file using the '%s' "
"driver is deprecated", bs->drv->format_name);
} else if (S_ISCHR(st.st_mode)) {
warn_report("Opening a character device as a file using the '%s' "
"driver is deprecated", bs->drv->format_name);
} else if (!S_ISREG(st.st_mode)) {
error_setg(errp, "A regular file was expected by the '%s' driver, "
"but something else was given", bs->drv->format_name);
ret = -EINVAL;
goto fail;
} else {
s->discard_zeroes = true;
s->has_fallocate = true;
}
} else {
if (!(S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode))) {
error_setg(errp, "'%s' driver expects either "
"a character or block device", bs->drv->format_name);
ret = -EINVAL;
goto fail;
}
}
if (S_ISBLK(st.st_mode)) {
#ifdef BLKDISCARDZEROES
unsigned int arg;
if (ioctl(s->fd, BLKDISCARDZEROES, &arg) == 0 && arg) {
s->discard_zeroes = true;
}
#endif
#ifdef __linux__
/* On Linux 3.10, BLKDISCARD leaves stale data in the page cache. Do
* not rely on the contents of discarded blocks unless using O_DIRECT.
* Same for BLKZEROOUT.
*/
if (!(bs->open_flags & BDRV_O_NOCACHE)) {
s->discard_zeroes = false;
s->has_write_zeroes = false;
}
#endif
}
#ifdef __FreeBSD__
if (S_ISCHR(st.st_mode)) {
/*
* The file is a char device (disk), which on FreeBSD isn't behind
* a pager, so force all requests to be aligned. This is needed
* so QEMU makes sure all IO operations on the device are aligned
* to sector size, or else FreeBSD will reject them with EINVAL.
*/
s->needs_alignment = true;
}
#endif
#ifdef CONFIG_XFS
if (platform_test_xfs_fd(s->fd)) {
s->is_xfs = true;
}
#endif
bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK;
ret = 0;
fail:
if (filename && (bdrv_flags & BDRV_O_TEMPORARY)) {
unlink(filename);
}
qemu_opts_del(opts);
return ret;
}
static int raw_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVRawState *s = bs->opaque;
s->type = FTYPE_FILE;
return raw_open_common(bs, options, flags, 0, false, errp);
}
typedef enum {
RAW_PL_PREPARE,
RAW_PL_COMMIT,
RAW_PL_ABORT,
} RawPermLockOp;
#define PERM_FOREACH(i) \
for ((i) = 0; (1ULL << (i)) <= BLK_PERM_ALL; i++)
/* Lock bytes indicated by @perm_lock_bits and @shared_perm_lock_bits in the
* file; if @unlock == true, also unlock the unneeded bytes.
* @shared_perm_lock_bits is the mask of all permissions that are NOT shared.
*/
static int raw_apply_lock_bytes(BDRVRawState *s, int fd,
uint64_t perm_lock_bits,
uint64_t shared_perm_lock_bits,
bool unlock, Error **errp)
{
int ret;
int i;
uint64_t locked_perm, locked_shared_perm;
if (s) {
locked_perm = s->locked_perm;
locked_shared_perm = s->locked_shared_perm;
} else {
/*
* We don't have the previous bits, just lock/unlock for each of the
* requested bits.
*/
if (unlock) {
locked_perm = BLK_PERM_ALL;
locked_shared_perm = BLK_PERM_ALL;
} else {
locked_perm = 0;
locked_shared_perm = 0;
}
}
PERM_FOREACH(i) {
int off = RAW_LOCK_PERM_BASE + i;
uint64_t bit = (1ULL << i);
if ((perm_lock_bits & bit) && !(locked_perm & bit)) {
ret = qemu_lock_fd(fd, off, 1, false);
if (ret) {
error_setg(errp, "Failed to lock byte %d", off);
return ret;
} else if (s) {
s->locked_perm |= bit;
}
} else if (unlock && (locked_perm & bit) && !(perm_lock_bits & bit)) {
ret = qemu_unlock_fd(fd, off, 1);
if (ret) {
error_setg(errp, "Failed to unlock byte %d", off);
return ret;
} else if (s) {
s->locked_perm &= ~bit;
}
}
}
PERM_FOREACH(i) {
int off = RAW_LOCK_SHARED_BASE + i;
uint64_t bit = (1ULL << i);
if ((shared_perm_lock_bits & bit) && !(locked_shared_perm & bit)) {
ret = qemu_lock_fd(fd, off, 1, false);
if (ret) {
error_setg(errp, "Failed to lock byte %d", off);
return ret;
} else if (s) {
s->locked_shared_perm |= bit;
}
} else if (unlock && (locked_shared_perm & bit) &&
!(shared_perm_lock_bits & bit)) {
ret = qemu_unlock_fd(fd, off, 1);
if (ret) {
error_setg(errp, "Failed to unlock byte %d", off);
return ret;
} else if (s) {
s->locked_shared_perm &= ~bit;
}
}
}
return 0;
}
/* Check "unshared" bytes implied by @perm and ~@shared_perm in the file. */
static int raw_check_lock_bytes(int fd, uint64_t perm, uint64_t shared_perm,
Error **errp)
{
int ret;
int i;
PERM_FOREACH(i) {
int off = RAW_LOCK_SHARED_BASE + i;
uint64_t p = 1ULL << i;
if (perm & p) {
ret = qemu_lock_fd_test(fd, off, 1, true);
if (ret) {
char *perm_name = bdrv_perm_names(p);
error_setg(errp,
"Failed to get \"%s\" lock",
perm_name);
g_free(perm_name);
return ret;
}
}
}
PERM_FOREACH(i) {
int off = RAW_LOCK_PERM_BASE + i;
uint64_t p = 1ULL << i;
if (!(shared_perm & p)) {
ret = qemu_lock_fd_test(fd, off, 1, true);
if (ret) {
char *perm_name = bdrv_perm_names(p);
error_setg(errp,
"Failed to get shared \"%s\" lock",
perm_name);
g_free(perm_name);
return ret;
}
}
}
return 0;
}
static int raw_handle_perm_lock(BlockDriverState *bs,
RawPermLockOp op,
uint64_t new_perm, uint64_t new_shared,
Error **errp)
{
BDRVRawState *s = bs->opaque;
int ret = 0;
Error *local_err = NULL;
if (!s->use_lock) {
return 0;
}
if (bdrv_get_flags(bs) & BDRV_O_INACTIVE) {
return 0;
}
switch (op) {
case RAW_PL_PREPARE:
if ((s->perm | new_perm) == s->perm &&
(s->shared_perm & new_shared) == s->shared_perm)
{
/*
* We are going to unlock bytes, it should not fail. If it fail due
* to some fs-dependent permission-unrelated reasons (which occurs
* sometimes on NFS and leads to abort in bdrv_replace_child) we
* can't prevent such errors by any check here. And we ignore them
* anyway in ABORT and COMMIT.
*/
return 0;
}
ret = raw_apply_lock_bytes(s, s->fd, s->perm | new_perm,
~s->shared_perm | ~new_shared,
false, errp);
if (!ret) {
ret = raw_check_lock_bytes(s->fd, new_perm, new_shared, errp);
if (!ret) {
return 0;
}
error_append_hint(errp,
"Is another process using the image [%s]?\n",
bs->filename);
}
/* fall through to unlock bytes. */
case RAW_PL_ABORT:
raw_apply_lock_bytes(s, s->fd, s->perm, ~s->shared_perm,
true, &local_err);
if (local_err) {
/* Theoretically the above call only unlocks bytes and it cannot
* fail. Something weird happened, report it.
*/
warn_report_err(local_err);
}
break;
case RAW_PL_COMMIT:
raw_apply_lock_bytes(s, s->fd, new_perm, ~new_shared,
true, &local_err);
if (local_err) {
/* Theoretically the above call only unlocks bytes and it cannot
* fail. Something weird happened, report it.
*/
warn_report_err(local_err);
}
break;
}
return ret;
}
static int raw_reconfigure_getfd(BlockDriverState *bs, int flags,
int *open_flags, uint64_t perm, bool force_dup,
Error **errp)
{
BDRVRawState *s = bs->opaque;
int fd = -1;
int ret;
bool has_writers = perm &
(BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED | BLK_PERM_RESIZE);
int fcntl_flags = O_APPEND | O_NONBLOCK;
#ifdef O_NOATIME
fcntl_flags |= O_NOATIME;
#endif
*open_flags = 0;
if (s->type == FTYPE_CD) {
*open_flags |= O_NONBLOCK;
}
raw_parse_flags(flags, open_flags, has_writers);
#ifdef O_ASYNC
/* Not all operating systems have O_ASYNC, and those that don't
* will not let us track the state into rs->open_flags (typically
* you achieve the same effect with an ioctl, for example I_SETSIG
* on Solaris). But we do not use O_ASYNC, so that's fine.
*/
assert((s->open_flags & O_ASYNC) == 0);
#endif
if (!force_dup && *open_flags == s->open_flags) {
/* We're lucky, the existing fd is fine */
return s->fd;
}
if ((*open_flags & ~fcntl_flags) == (s->open_flags & ~fcntl_flags)) {
/* dup the original fd */
fd = qemu_dup(s->fd);
if (fd >= 0) {
ret = fcntl_setfl(fd, *open_flags);
if (ret) {
qemu_close(fd);
fd = -1;
}
}
}
/* If we cannot use fcntl, or fcntl failed, fall back to qemu_open() */
if (fd == -1) {
const char *normalized_filename = bs->filename;
ret = raw_normalize_devicepath(&normalized_filename, errp);
if (ret >= 0) {
assert(!(*open_flags & O_CREAT));
fd = qemu_open(normalized_filename, *open_flags);
if (fd == -1) {
error_setg_errno(errp, errno, "Could not reopen file");
return -1;
}
}
}
return fd;
}
static int raw_reopen_prepare(BDRVReopenState *state,
BlockReopenQueue *queue, Error **errp)
{
BDRVRawState *s;
BDRVRawReopenState *rs;
QemuOpts *opts;
int ret;
Error *local_err = NULL;
assert(state != NULL);
assert(state->bs != NULL);
s = state->bs->opaque;
state->opaque = g_new0(BDRVRawReopenState, 1);
rs = state->opaque;
/* Handle options changes */
opts = qemu_opts_create(&raw_runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, state->options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto out;
}
rs->drop_cache = qemu_opt_get_bool_del(opts, "drop-cache", true);
rs->check_cache_dropped =
qemu_opt_get_bool_del(opts, "x-check-cache-dropped", false);
/* This driver's reopen function doesn't currently allow changing
* other options, so let's put them back in the original QDict and
* bdrv_reopen_prepare() will detect changes and complain. */
qemu_opts_to_qdict(opts, state->options);
rs->fd = raw_reconfigure_getfd(state->bs, state->flags, &rs->open_flags,
state->perm, true, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -1;
goto out;
}
/* Fail already reopen_prepare() if we can't get a working O_DIRECT
* alignment with the new fd. */
if (rs->fd != -1) {
raw_probe_alignment(state->bs, rs->fd, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto out_fd;
}
}
s->reopen_state = state;
ret = 0;
out_fd:
if (ret < 0) {
qemu_close(rs->fd);
rs->fd = -1;
}
out:
qemu_opts_del(opts);
return ret;
}
static void raw_reopen_commit(BDRVReopenState *state)
{
BDRVRawReopenState *rs = state->opaque;
BDRVRawState *s = state->bs->opaque;
s->drop_cache = rs->drop_cache;
s->check_cache_dropped = rs->check_cache_dropped;
s->open_flags = rs->open_flags;
qemu_close(s->fd);
s->fd = rs->fd;
g_free(state->opaque);
state->opaque = NULL;
assert(s->reopen_state == state);
s->reopen_state = NULL;
}
static void raw_reopen_abort(BDRVReopenState *state)
{
BDRVRawReopenState *rs = state->opaque;
BDRVRawState *s = state->bs->opaque;
/* nothing to do if NULL, we didn't get far enough */
if (rs == NULL) {
return;
}
if (rs->fd >= 0) {
qemu_close(rs->fd);
rs->fd = -1;
}
g_free(state->opaque);
state->opaque = NULL;
assert(s->reopen_state == state);
s->reopen_state = NULL;
}
static int sg_get_max_transfer_length(int fd)
{
#ifdef BLKSECTGET
int max_bytes = 0;
if (ioctl(fd, BLKSECTGET, &max_bytes) == 0) {
return max_bytes;
} else {
return -errno;
}
#else
return -ENOSYS;
#endif
}
static int sg_get_max_segments(int fd)
{
#ifdef CONFIG_LINUX
char buf[32];
const char *end;
char *sysfspath = NULL;
int ret;
int sysfd = -1;
long max_segments;
struct stat st;
if (fstat(fd, &st)) {
ret = -errno;
goto out;
}
sysfspath = g_strdup_printf("/sys/dev/block/%u:%u/queue/max_segments",
major(st.st_rdev), minor(st.st_rdev));
sysfd = open(sysfspath, O_RDONLY);
if (sysfd == -1) {
ret = -errno;
goto out;
}
do {
ret = read(sysfd, buf, sizeof(buf) - 1);
} while (ret == -1 && errno == EINTR);
if (ret < 0) {
ret = -errno;
goto out;
} else if (ret == 0) {
ret = -EIO;
goto out;
}
buf[ret] = 0;
/* The file is ended with '\n', pass 'end' to accept that. */
ret = qemu_strtol(buf, &end, 10, &max_segments);
if (ret == 0 && end && *end == '\n') {
ret = max_segments;
}
out:
if (sysfd != -1) {
close(sysfd);
}
g_free(sysfspath);
return ret;
#else
return -ENOTSUP;
#endif
}
static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
{
BDRVRawState *s = bs->opaque;
if (bs->sg) {
int ret = sg_get_max_transfer_length(s->fd);
if (ret > 0 && ret <= BDRV_REQUEST_MAX_BYTES) {
bs->bl.max_transfer = pow2floor(ret);
}
ret = sg_get_max_segments(s->fd);
if (ret > 0) {
bs->bl.max_transfer = MIN(bs->bl.max_transfer,
ret * qemu_real_host_page_size);
}
}
raw_probe_alignment(bs, s->fd, errp);
bs->bl.min_mem_alignment = s->buf_align;
bs->bl.opt_mem_alignment = MAX(s->buf_align, qemu_real_host_page_size);
}
static int check_for_dasd(int fd)
{
#ifdef BIODASDINFO2
struct dasd_information2_t info = {0};
return ioctl(fd, BIODASDINFO2, &info);
#else
return -1;
#endif
}
/**
* Try to get @bs's logical and physical block size.
* On success, store them in @bsz and return zero.
* On failure, return negative errno.
*/
static int hdev_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
{
BDRVRawState *s = bs->opaque;
int ret;
/* If DASD, get blocksizes */
if (check_for_dasd(s->fd) < 0) {
return -ENOTSUP;
}
ret = probe_logical_blocksize(s->fd, &bsz->log);
if (ret < 0) {
return ret;
}
return probe_physical_blocksize(s->fd, &bsz->phys);
}
/**
* Try to get @bs's geometry: cyls, heads, sectors.
* On success, store them in @geo and return 0.
* On failure return -errno.
* (Allows block driver to assign default geometry values that guest sees)
*/
#ifdef __linux__
static int hdev_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
{
BDRVRawState *s = bs->opaque;
struct hd_geometry ioctl_geo = {0};
/* If DASD, get its geometry */
if (check_for_dasd(s->fd) < 0) {
return -ENOTSUP;
}
if (ioctl(s->fd, HDIO_GETGEO, &ioctl_geo) < 0) {
return -errno;
}
/* HDIO_GETGEO may return success even though geo contains zeros
(e.g. certain multipath setups) */
if (!ioctl_geo.heads || !ioctl_geo.sectors || !ioctl_geo.cylinders) {
return -ENOTSUP;
}
/* Do not return a geometry for partition */
if (ioctl_geo.start != 0) {
return -ENOTSUP;
}
geo->heads = ioctl_geo.heads;
geo->sectors = ioctl_geo.sectors;
geo->cylinders = ioctl_geo.cylinders;
return 0;
}
#else /* __linux__ */
static int hdev_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
{
return -ENOTSUP;
}
#endif
#if defined(__linux__)
static int handle_aiocb_ioctl(void *opaque)
{
RawPosixAIOData *aiocb = opaque;
int ret;
ret = ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd, aiocb->ioctl.buf);
if (ret == -1) {
return -errno;
}
return 0;
}
#endif /* linux */
static int handle_aiocb_flush(void *opaque)
{
RawPosixAIOData *aiocb = opaque;
BDRVRawState *s = aiocb->bs->opaque;
int ret;
if (s->page_cache_inconsistent) {
return -EIO;
}
ret = qemu_fdatasync(aiocb->aio_fildes);
if (ret == -1) {
/* There is no clear definition of the semantics of a failing fsync(),
* so we may have to assume the worst. The sad truth is that this
* assumption is correct for Linux. Some pages are now probably marked
* clean in the page cache even though they are inconsistent with the
* on-disk contents. The next fdatasync() call would succeed, but no
* further writeback attempt will be made. We can't get back to a state
* in which we know what is on disk (we would have to rewrite
* everything that was touched since the last fdatasync() at least), so
* make bdrv_flush() fail permanently. Given that the behaviour isn't
* really defined, I have little hope that other OSes are doing better.
*
* Obviously, this doesn't affect O_DIRECT, which bypasses the page
* cache. */
if ((s->open_flags & O_DIRECT) == 0) {
s->page_cache_inconsistent = true;
}
return -errno;
}
return 0;
}
#ifdef CONFIG_PREADV
static bool preadv_present = true;
static ssize_t
qemu_preadv(int fd, const struct iovec *iov, int nr_iov, off_t offset)
{
return preadv(fd, iov, nr_iov, offset);
}
static ssize_t
qemu_pwritev(int fd, const struct iovec *iov, int nr_iov, off_t offset)
{
return pwritev(fd, iov, nr_iov, offset);
}
#else
static bool preadv_present = false;
static ssize_t
qemu_preadv(int fd, const struct iovec *iov, int nr_iov, off_t offset)
{
return -ENOSYS;
}
static ssize_t
qemu_pwritev(int fd, const struct iovec *iov, int nr_iov, off_t offset)
{
return -ENOSYS;
}
#endif
static ssize_t handle_aiocb_rw_vector(RawPosixAIOData *aiocb)
{
ssize_t len;
do {
if (aiocb->aio_type & QEMU_AIO_WRITE)
len = qemu_pwritev(aiocb->aio_fildes,
aiocb->io.iov,
aiocb->io.niov,
aiocb->aio_offset);
else
len = qemu_preadv(aiocb->aio_fildes,
aiocb->io.iov,
aiocb->io.niov,
aiocb->aio_offset);
} while (len == -1 && errno == EINTR);
if (len == -1) {
return -errno;
}
return len;
}
/*
* Read/writes the data to/from a given linear buffer.
*
* Returns the number of bytes handles or -errno in case of an error. Short
* reads are only returned if the end of the file is reached.
*/
static ssize_t handle_aiocb_rw_linear(RawPosixAIOData *aiocb, char *buf)
{
ssize_t offset = 0;
ssize_t len;
while (offset < aiocb->aio_nbytes) {
if (aiocb->aio_type & QEMU_AIO_WRITE) {
len = pwrite(aiocb->aio_fildes,
(const char *)buf + offset,
aiocb->aio_nbytes - offset,
aiocb->aio_offset + offset);
} else {
len = pread(aiocb->aio_fildes,
buf + offset,
aiocb->aio_nbytes - offset,
aiocb->aio_offset + offset);
}
if (len == -1 && errno == EINTR) {
continue;
} else if (len == -1 && errno == EINVAL &&
(aiocb->bs->open_flags & BDRV_O_NOCACHE) &&
!(aiocb->aio_type & QEMU_AIO_WRITE) &&
offset > 0) {
/* O_DIRECT pread() may fail with EINVAL when offset is unaligned
* after a short read. Assume that O_DIRECT short reads only occur
* at EOF. Therefore this is a short read, not an I/O error.
*/
break;
} else if (len == -1) {
offset = -errno;
break;
} else if (len == 0) {
break;
}
offset += len;
}
return offset;
}
static int handle_aiocb_rw(void *opaque)
{
RawPosixAIOData *aiocb = opaque;
ssize_t nbytes;
char *buf;
if (!(aiocb->aio_type & QEMU_AIO_MISALIGNED)) {
/*
* If there is just a single buffer, and it is properly aligned
* we can just use plain pread/pwrite without any problems.
*/
if (aiocb->io.niov == 1) {
nbytes = handle_aiocb_rw_linear(aiocb, aiocb->io.iov->iov_base);
goto out;
}
/*
* We have more than one iovec, and all are properly aligned.
*
* Try preadv/pwritev first and fall back to linearizing the
* buffer if it's not supported.
*/
if (preadv_present) {
nbytes = handle_aiocb_rw_vector(aiocb);
if (nbytes == aiocb->aio_nbytes ||
(nbytes < 0 && nbytes != -ENOSYS)) {
goto out;
}
preadv_present = false;
}
/*
* XXX(hch): short read/write. no easy way to handle the reminder
* using these interfaces. For now retry using plain
* pread/pwrite?
*/
}
/*
* Ok, we have to do it the hard way, copy all segments into
* a single aligned buffer.
*/
buf = qemu_try_blockalign(aiocb->bs, aiocb->aio_nbytes);
if (buf == NULL) {
nbytes = -ENOMEM;
goto out;
}
if (aiocb->aio_type & QEMU_AIO_WRITE) {
char *p = buf;
int i;
for (i = 0; i < aiocb->io.niov; ++i) {
memcpy(p, aiocb->io.iov[i].iov_base, aiocb->io.iov[i].iov_len);
p += aiocb->io.iov[i].iov_len;
}
assert(p - buf == aiocb->aio_nbytes);
}
nbytes = handle_aiocb_rw_linear(aiocb, buf);
if (!(aiocb->aio_type & QEMU_AIO_WRITE)) {
char *p = buf;
size_t count = aiocb->aio_nbytes, copy;
int i;
for (i = 0; i < aiocb->io.niov && count; ++i) {
copy = count;
if (copy > aiocb->io.iov[i].iov_len) {
copy = aiocb->io.iov[i].iov_len;
}
memcpy(aiocb->io.iov[i].iov_base, p, copy);
assert(count >= copy);
p += copy;
count -= copy;
}
assert(count == 0);
}
qemu_vfree(buf);
out:
if (nbytes == aiocb->aio_nbytes) {
return 0;
} else if (nbytes >= 0 && nbytes < aiocb->aio_nbytes) {
if (aiocb->aio_type & QEMU_AIO_WRITE) {
return -EINVAL;
} else {
iov_memset(aiocb->io.iov, aiocb->io.niov, nbytes,
0, aiocb->aio_nbytes - nbytes);
return 0;
}
} else {
assert(nbytes < 0);
return nbytes;
}
}
static int translate_err(int err)
{
if (err == -ENODEV || err == -ENOSYS || err == -EOPNOTSUPP ||
err == -ENOTTY) {
err = -ENOTSUP;
}
return err;
}
#ifdef CONFIG_FALLOCATE
static int do_fallocate(int fd, int mode, off_t offset, off_t len)
{
do {
if (fallocate(fd, mode, offset, len) == 0) {
return 0;
}
} while (errno == EINTR);
return translate_err(-errno);
}
#endif
static ssize_t handle_aiocb_write_zeroes_block(RawPosixAIOData *aiocb)
{
int ret = -ENOTSUP;
BDRVRawState *s = aiocb->bs->opaque;
if (!s->has_write_zeroes) {
return -ENOTSUP;
}
#ifdef BLKZEROOUT
/* The BLKZEROOUT implementation in the kernel doesn't set
* BLKDEV_ZERO_NOFALLBACK, so we can't call this if we have to avoid slow
* fallbacks. */
if (!(aiocb->aio_type & QEMU_AIO_NO_FALLBACK)) {
do {
uint64_t range[2] = { aiocb->aio_offset, aiocb->aio_nbytes };
if (ioctl(aiocb->aio_fildes, BLKZEROOUT, range) == 0) {
return 0;
}
} while (errno == EINTR);
ret = translate_err(-errno);
if (ret == -ENOTSUP) {
s->has_write_zeroes = false;
}
}
#endif
return ret;
}
static int handle_aiocb_write_zeroes(void *opaque)
{
RawPosixAIOData *aiocb = opaque;
#ifdef CONFIG_FALLOCATE
BDRVRawState *s = aiocb->bs->opaque;
int64_t len;
#endif
if (aiocb->aio_type & QEMU_AIO_BLKDEV) {
return handle_aiocb_write_zeroes_block(aiocb);
}
#ifdef CONFIG_FALLOCATE_ZERO_RANGE
if (s->has_write_zeroes) {
int ret = do_fallocate(s->fd, FALLOC_FL_ZERO_RANGE,
aiocb->aio_offset, aiocb->aio_nbytes);
if (ret == -EINVAL) {
/*
* Allow falling back to pwrite for file systems that
* do not support fallocate() for an unaligned byte range.
*/
return -ENOTSUP;
}
if (ret == 0 || ret != -ENOTSUP) {
return ret;
}
s->has_write_zeroes = false;
}
#endif
#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
if (s->has_discard && s->has_fallocate) {
int ret = do_fallocate(s->fd,
FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
aiocb->aio_offset, aiocb->aio_nbytes);
if (ret == 0) {
ret = do_fallocate(s->fd, 0, aiocb->aio_offset, aiocb->aio_nbytes);
if (ret == 0 || ret != -ENOTSUP) {
return ret;
}
s->has_fallocate = false;
} else if (ret != -ENOTSUP) {
return ret;
} else {
s->has_discard = false;
}
}
#endif
#ifdef CONFIG_FALLOCATE
/* Last resort: we are trying to extend the file with zeroed data. This
* can be done via fallocate(fd, 0) */
len = bdrv_getlength(aiocb->bs);
if (s->has_fallocate && len >= 0 && aiocb->aio_offset >= len) {
int ret = do_fallocate(s->fd, 0, aiocb->aio_offset, aiocb->aio_nbytes);
if (ret == 0 || ret != -ENOTSUP) {
return ret;
}
s->has_fallocate = false;
}
#endif
return -ENOTSUP;
}
static int handle_aiocb_write_zeroes_unmap(void *opaque)
{
RawPosixAIOData *aiocb = opaque;
BDRVRawState *s G_GNUC_UNUSED = aiocb->bs->opaque;
int ret;
/* First try to write zeros and unmap at the same time */
#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
ret = do_fallocate(s->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
aiocb->aio_offset, aiocb->aio_nbytes);
if (ret != -ENOTSUP) {
return ret;
}
#endif
/* If we couldn't manage to unmap while guaranteed that the area reads as
* all-zero afterwards, just write zeroes without unmapping */
ret = handle_aiocb_write_zeroes(aiocb);
return ret;
}
#ifndef HAVE_COPY_FILE_RANGE
static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
off_t *out_off, size_t len, unsigned int flags)
{
#ifdef __NR_copy_file_range
return syscall(__NR_copy_file_range, in_fd, in_off, out_fd,
out_off, len, flags);
#else
errno = ENOSYS;
return -1;
#endif
}
#endif
static int handle_aiocb_copy_range(void *opaque)
{
RawPosixAIOData *aiocb = opaque;
uint64_t bytes = aiocb->aio_nbytes;
off_t in_off = aiocb->aio_offset;
off_t out_off = aiocb->copy_range.aio_offset2;
while (bytes) {
ssize_t ret = copy_file_range(aiocb->aio_fildes, &in_off,
aiocb->copy_range.aio_fd2, &out_off,
bytes, 0);
trace_file_copy_file_range(aiocb->bs, aiocb->aio_fildes, in_off,
aiocb->copy_range.aio_fd2, out_off, bytes,
0, ret);
if (ret == 0) {
/* No progress (e.g. when beyond EOF), let the caller fall back to
* buffer I/O. */
return -ENOSPC;
}
if (ret < 0) {
switch (errno) {
case ENOSYS:
return -ENOTSUP;
case EINTR:
continue;
default:
return -errno;
}
}
bytes -= ret;
}
return 0;
}
static int handle_aiocb_discard(void *opaque)
{
RawPosixAIOData *aiocb = opaque;
int ret = -EOPNOTSUPP;
BDRVRawState *s = aiocb->bs->opaque;
if (!s->has_discard) {
return -ENOTSUP;
}
if (aiocb->aio_type & QEMU_AIO_BLKDEV) {
#ifdef BLKDISCARD
do {
uint64_t range[2] = { aiocb->aio_offset, aiocb->aio_nbytes };
if (ioctl(aiocb->aio_fildes, BLKDISCARD, range) == 0) {
return 0;
}
} while (errno == EINTR);
ret = -errno;
#endif
} else {
#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
ret = do_fallocate(s->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
aiocb->aio_offset, aiocb->aio_nbytes);
#endif
}
ret = translate_err(ret);
if (ret == -ENOTSUP) {
s->has_discard = false;
}
return ret;
}
/*
* Help alignment probing by allocating the first block.
*
* When reading with direct I/O from unallocated area on Gluster backed by XFS,
* reading succeeds regardless of request length. In this case we fallback to
* safe alignment which is not optimal. Allocating the first block avoids this
* fallback.
*
* fd may be opened with O_DIRECT, but we don't know the buffer alignment or
* request alignment, so we use safe values.
*
* Returns: 0 on success, -errno on failure. Since this is an optimization,
* caller may ignore failures.
*/
static int allocate_first_block(int fd, size_t max_size)
{
size_t write_size = (max_size < MAX_BLOCKSIZE)
? BDRV_SECTOR_SIZE
: MAX_BLOCKSIZE;
size_t max_align = MAX(MAX_BLOCKSIZE, qemu_real_host_page_size);
void *buf;
ssize_t n;
int ret;
buf = qemu_memalign(max_align, write_size);
memset(buf, 0, write_size);
do {
n = pwrite(fd, buf, write_size, 0);
} while (n == -1 && errno == EINTR);
ret = (n == -1) ? -errno : 0;
qemu_vfree(buf);
return ret;
}
static int handle_aiocb_truncate(void *opaque)
{
RawPosixAIOData *aiocb = opaque;
int result = 0;
int64_t current_length = 0;
char *buf = NULL;
struct stat st;
int fd = aiocb->aio_fildes;
int64_t offset = aiocb->aio_offset;
PreallocMode prealloc = aiocb->truncate.prealloc;
Error **errp = aiocb->truncate.errp;
if (fstat(fd, &st) < 0) {
result = -errno;
error_setg_errno(errp, -result, "Could not stat file");
return result;
}
current_length = st.st_size;
if (current_length > offset && prealloc != PREALLOC_MODE_OFF) {
error_setg(errp, "Cannot use preallocation for shrinking files");
return -ENOTSUP;
}
switch (prealloc) {
#ifdef CONFIG_POSIX_FALLOCATE
case PREALLOC_MODE_FALLOC:
/*
* Truncating before posix_fallocate() makes it about twice slower on
* file systems that do not support fallocate(), trying to check if a
* block is allocated before allocating it, so don't do that here.
*/
if (offset != current_length) {
result = -posix_fallocate(fd, current_length,
offset - current_length);
if (result != 0) {
/* posix_fallocate() doesn't set errno. */
error_setg_errno(errp, -result,
"Could not preallocate new data");
} else if (current_length == 0) {
/*
* posix_fallocate() uses fallocate() if the filesystem
* supports it, or fallback to manually writing zeroes. If
* fallocate() was used, unaligned reads from the fallocated
* area in raw_probe_alignment() will succeed, hence we need to
* allocate the first block.
*
* Optimize future alignment probing; ignore failures.
*/
allocate_first_block(fd, offset);
}
} else {
result = 0;
}
goto out;
#endif
case PREALLOC_MODE_FULL:
{
int64_t num = 0, left = offset - current_length;
off_t seek_result;
/*
* Knowing the final size from the beginning could allow the file
* system driver to do less allocations and possibly avoid
* fragmentation of the file.
*/
if (ftruncate(fd, offset) != 0) {
result = -errno;
error_setg_errno(errp, -result, "Could not resize file");
goto out;
}
buf = g_malloc0(65536);
seek_result = lseek(fd, current_length, SEEK_SET);
if (seek_result < 0) {
result = -errno;
error_setg_errno(errp, -result,
"Failed to seek to the old end of file");
goto out;
}
while (left > 0) {
num = MIN(left, 65536);
result = write(fd, buf, num);
if (result < 0) {
if (errno == EINTR) {
continue;
}
result = -errno;
error_setg_errno(errp, -result,
"Could not write zeros for preallocation");
goto out;
}
left -= result;
}
if (result >= 0) {
result = fsync(fd);
if (result < 0) {
result = -errno;
error_setg_errno(errp, -result,
"Could not flush file to disk");
goto out;
}
}
goto out;
}
case PREALLOC_MODE_OFF:
if (ftruncate(fd, offset) != 0) {
result = -errno;
error_setg_errno(errp, -result, "Could not resize file");
} else if (current_length == 0 && offset > current_length) {
/* Optimize future alignment probing; ignore failures. */
allocate_first_block(fd, offset);
}
return result;
default:
result = -ENOTSUP;
error_setg(errp, "Unsupported preallocation mode: %s",
PreallocMode_str(prealloc));
return result;
}
out:
if (result < 0) {
if (ftruncate(fd, current_length) < 0) {
error_report("Failed to restore old file length: %s",
strerror(errno));
}
}
g_free(buf);
return result;
}
static int coroutine_fn raw_thread_pool_submit(BlockDriverState *bs,
ThreadPoolFunc func, void *arg)
{
/* @bs can be NULL, bdrv_get_aio_context() returns the main context then */
ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
return thread_pool_submit_co(pool, func, arg);
}
static int coroutine_fn raw_co_prw(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov, int type)
{
BDRVRawState *s = bs->opaque;
RawPosixAIOData acb;
if (fd_open(bs) < 0)
return -EIO;
/*
* When using O_DIRECT, the request must be aligned to be able to use
* either libaio or io_uring interface. If not fail back to regular thread
* pool read/write code which emulates this for us if we
* set QEMU_AIO_MISALIGNED.
*/
if (s->needs_alignment && !bdrv_qiov_is_aligned(bs, qiov)) {
type |= QEMU_AIO_MISALIGNED;
#ifdef CONFIG_LINUX_IO_URING
} else if (s->use_linux_io_uring) {
LuringState *aio = aio_get_linux_io_uring(bdrv_get_aio_context(bs));
assert(qiov->size == bytes);
return luring_co_submit(bs, aio, s->fd, offset, qiov, type);
#endif
#ifdef CONFIG_LINUX_AIO
} else if (s->use_linux_aio) {
LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
assert(qiov->size == bytes);
return laio_co_submit(bs, aio, s->fd, offset, qiov, type);
#endif
}
acb = (RawPosixAIOData) {
.bs = bs,
.aio_fildes = s->fd,
.aio_type = type,
.aio_offset = offset,
.aio_nbytes = bytes,
.io = {
.iov = qiov->iov,
.niov = qiov->niov,
},
};
assert(qiov->size == bytes);
return raw_thread_pool_submit(bs, handle_aiocb_rw, &acb);
}
static int coroutine_fn raw_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
return raw_co_prw(bs, offset, bytes, qiov, QEMU_AIO_READ);
}
static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
assert(flags == 0);
return raw_co_prw(bs, offset, bytes, qiov, QEMU_AIO_WRITE);
}
static void raw_aio_plug(BlockDriverState *bs)
{
BDRVRawState __attribute__((unused)) *s = bs->opaque;
#ifdef CONFIG_LINUX_AIO
if (s->use_linux_aio) {
LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
laio_io_plug(bs, aio);
}
#endif
#ifdef CONFIG_LINUX_IO_URING
if (s->use_linux_io_uring) {
LuringState *aio = aio_get_linux_io_uring(bdrv_get_aio_context(bs));
luring_io_plug(bs, aio);
}
#endif
}
static void raw_aio_unplug(BlockDriverState *bs)
{
BDRVRawState __attribute__((unused)) *s = bs->opaque;
#ifdef CONFIG_LINUX_AIO
if (s->use_linux_aio) {
LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
laio_io_unplug(bs, aio);
}
#endif
#ifdef CONFIG_LINUX_IO_URING
if (s->use_linux_io_uring) {
LuringState *aio = aio_get_linux_io_uring(bdrv_get_aio_context(bs));
luring_io_unplug(bs, aio);
}
#endif
}
static int raw_co_flush_to_disk(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
RawPosixAIOData acb;
int ret;
ret = fd_open(bs);
if (ret < 0) {
return ret;
}
acb = (RawPosixAIOData) {
.bs = bs,
.aio_fildes = s->fd,
.aio_type = QEMU_AIO_FLUSH,
};
#ifdef CONFIG_LINUX_IO_URING
if (s->use_linux_io_uring) {
LuringState *aio = aio_get_linux_io_uring(bdrv_get_aio_context(bs));
return luring_co_submit(bs, aio, s->fd, 0, NULL, QEMU_AIO_FLUSH);
}
#endif
return raw_thread_pool_submit(bs, handle_aiocb_flush, &acb);
}
static void raw_aio_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
BDRVRawState __attribute__((unused)) *s = bs->opaque;
#ifdef CONFIG_LINUX_AIO
if (s->use_linux_aio) {
Error *local_err = NULL;
if (!aio_setup_linux_aio(new_context, &local_err)) {
error_reportf_err(local_err, "Unable to use native AIO, "
"falling back to thread pool: ");
s->use_linux_aio = false;
}
}
#endif
#ifdef CONFIG_LINUX_IO_URING
if (s->use_linux_io_uring) {
Error *local_err;
if (!aio_setup_linux_io_uring(new_context, &local_err)) {
error_reportf_err(local_err, "Unable to use linux io_uring, "
"falling back to thread pool: ");
s->use_linux_io_uring = false;
}
}
#endif
}
static void raw_close(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
if (s->fd >= 0) {
qemu_close(s->fd);
s->fd = -1;
}
}
/**
* Truncates the given regular file @fd to @offset and, when growing, fills the
* new space according to @prealloc.
*
* Returns: 0 on success, -errno on failure.
*/
static int coroutine_fn
raw_regular_truncate(BlockDriverState *bs, int fd, int64_t offset,
PreallocMode prealloc, Error **errp)
{
RawPosixAIOData acb;
acb = (RawPosixAIOData) {
.bs = bs,
.aio_fildes = fd,
.aio_type = QEMU_AIO_TRUNCATE,
.aio_offset = offset,
.truncate = {
.prealloc = prealloc,
.errp = errp,
},
};
return raw_thread_pool_submit(bs, handle_aiocb_truncate, &acb);
}
static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
bool exact, PreallocMode prealloc,
Error **errp)
{
BDRVRawState *s = bs->opaque;
struct stat st;
int ret;
if (fstat(s->fd, &st)) {
ret = -errno;
error_setg_errno(errp, -ret, "Failed to fstat() the file");
return ret;
}
if (S_ISREG(st.st_mode)) {
/* Always resizes to the exact @offset */
return raw_regular_truncate(bs, s->fd, offset, prealloc, errp);
}
if (prealloc != PREALLOC_MODE_OFF) {
error_setg(errp, "Preallocation mode '%s' unsupported for this "
"non-regular file", PreallocMode_str(prealloc));
return -ENOTSUP;
}
if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
int64_t cur_length = raw_getlength(bs);
if (offset != cur_length && exact) {
error_setg(errp, "Cannot resize device files");
return -ENOTSUP;
} else if (offset > cur_length) {
error_setg(errp, "Cannot grow device files");
return -EINVAL;
}
} else {
error_setg(errp, "Resizing this file is not supported");
return -ENOTSUP;
}
return 0;
}
#ifdef __OpenBSD__
static int64_t raw_getlength(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
int fd = s->fd;
struct stat st;
if (fstat(fd, &st))
return -errno;
if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
struct disklabel dl;
if (ioctl(fd, DIOCGDINFO, &dl))
return -errno;
return (uint64_t)dl.d_secsize *
dl.d_partitions[DISKPART(st.st_rdev)].p_size;
} else
return st.st_size;
}
#elif defined(__NetBSD__)
static int64_t raw_getlength(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
int fd = s->fd;
struct stat st;
if (fstat(fd, &st))
return -errno;
if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
struct dkwedge_info dkw;
if (ioctl(fd, DIOCGWEDGEINFO, &dkw) != -1) {
return dkw.dkw_size * 512;
} else {
struct disklabel dl;
if (ioctl(fd, DIOCGDINFO, &dl))
return -errno;
return (uint64_t)dl.d_secsize *
dl.d_partitions[DISKPART(st.st_rdev)].p_size;
}
} else
return st.st_size;
}
#elif defined(__sun__)
static int64_t raw_getlength(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
struct dk_minfo minfo;
int ret;
int64_t size;
ret = fd_open(bs);
if (ret < 0) {
return ret;
}
/*
* Use the DKIOCGMEDIAINFO ioctl to read the size.
*/
ret = ioctl(s->fd, DKIOCGMEDIAINFO, &minfo);
if (ret != -1) {
return minfo.dki_lbsize * minfo.dki_capacity;
}
/*
* There are reports that lseek on some devices fails, but
* irc discussion said that contingency on contingency was overkill.
*/
size = lseek(s->fd, 0, SEEK_END);
if (size < 0) {
return -errno;
}
return size;
}
#elif defined(CONFIG_BSD)
static int64_t raw_getlength(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
int fd = s->fd;
int64_t size;
struct stat sb;
#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
int reopened = 0;
#endif
int ret;
ret = fd_open(bs);
if (ret < 0)
return ret;
#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
again:
#endif
if (!fstat(fd, &sb) && (S_IFCHR & sb.st_mode)) {
#ifdef DIOCGMEDIASIZE
if (ioctl(fd, DIOCGMEDIASIZE, (off_t *)&size))
#elif defined(DIOCGPART)
{
struct partinfo pi;
if (ioctl(fd, DIOCGPART, &pi) == 0)
size = pi.media_size;
else
size = 0;
}
if (size == 0)
#endif
#if defined(__APPLE__) && defined(__MACH__)
{
uint64_t sectors = 0;
uint32_t sector_size = 0;
if (ioctl(fd, DKIOCGETBLOCKCOUNT, &sectors) == 0
&& ioctl(fd, DKIOCGETBLOCKSIZE, &sector_size) == 0) {
size = sectors * sector_size;
} else {
size = lseek(fd, 0LL, SEEK_END);
if (size < 0) {
return -errno;
}
}
}
#else
size = lseek(fd, 0LL, SEEK_END);
if (size < 0) {
return -errno;
}
#endif
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
switch(s->type) {
case FTYPE_CD:
/* XXX FreeBSD acd returns UINT_MAX sectors for an empty drive */
if (size == 2048LL * (unsigned)-1)
size = 0;
/* XXX no disc? maybe we need to reopen... */
if (size <= 0 && !reopened && cdrom_reopen(bs) >= 0) {
reopened = 1;
goto again;
}
}
#endif
} else {
size = lseek(fd, 0, SEEK_END);
if (size < 0) {
return -errno;
}
}
return size;
}
#else
static int64_t raw_getlength(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
int ret;
int64_t size;
ret = fd_open(bs);
if (ret < 0) {
return ret;
}
size = lseek(s->fd, 0, SEEK_END);
if (size < 0) {
return -errno;
}
return size;
}
#endif
static int64_t raw_get_allocated_file_size(BlockDriverState *bs)
{
struct stat st;
BDRVRawState *s = bs->opaque;
if (fstat(s->fd, &st) < 0) {
return -errno;
}
return (int64_t)st.st_blocks * 512;
}
static int coroutine_fn
raw_co_create(BlockdevCreateOptions *options, Error **errp)
{
BlockdevCreateOptionsFile *file_opts;
Error *local_err = NULL;
int fd;
uint64_t perm, shared;
int result = 0;
/* Validate options and set default values */
assert(options->driver == BLOCKDEV_DRIVER_FILE);
file_opts = &options->u.file;
if (!file_opts->has_nocow) {
file_opts->nocow = false;
}
if (!file_opts->has_preallocation) {
file_opts->preallocation = PREALLOC_MODE_OFF;
}
/* Create file */
fd = qemu_open(file_opts->filename, O_RDWR | O_CREAT | O_BINARY, 0644);
if (fd < 0) {
result = -errno;
error_setg_errno(errp, -result, "Could not create file");
goto out;
}
/* Take permissions: We want to discard everything, so we need
* BLK_PERM_WRITE; and truncation to the desired size requires
* BLK_PERM_RESIZE.
* On the other hand, we cannot share the RESIZE permission
* because we promise that after this function, the file has the
* size given in the options. If someone else were to resize it
* concurrently, we could not guarantee that.
* Note that after this function, we can no longer guarantee that
* the file is not touched by a third party, so it may be resized
* then. */
perm = BLK_PERM_WRITE | BLK_PERM_RESIZE;
shared = BLK_PERM_ALL & ~BLK_PERM_RESIZE;
/* Step one: Take locks */
result = raw_apply_lock_bytes(NULL, fd, perm, ~shared, false, errp);
if (result < 0) {
goto out_close;
}
/* Step two: Check that nobody else has taken conflicting locks */
result = raw_check_lock_bytes(fd, perm, shared, errp);
if (result < 0) {
error_append_hint(errp,
"Is another process using the image [%s]?\n",
file_opts->filename);
goto out_unlock;
}
/* Clear the file by truncating it to 0 */
result = raw_regular_truncate(NULL, fd, 0, PREALLOC_MODE_OFF, errp);
if (result < 0) {
goto out_unlock;
}
if (file_opts->nocow) {
#ifdef __linux__
/* Set NOCOW flag to solve performance issue on fs like btrfs.
* This is an optimisation. The FS_IOC_SETFLAGS ioctl return value
* will be ignored since any failure of this operation should not
* block the left work.
*/
int attr;
if (ioctl(fd, FS_IOC_GETFLAGS, &attr) == 0) {
attr |= FS_NOCOW_FL;
ioctl(fd, FS_IOC_SETFLAGS, &attr);
}
#endif
}
/* Resize and potentially preallocate the file to the desired
* final size */
result = raw_regular_truncate(NULL, fd, file_opts->size,
file_opts->preallocation, errp);
if (result < 0) {
goto out_unlock;
}
out_unlock:
raw_apply_lock_bytes(NULL, fd, 0, 0, true, &local_err);
if (local_err) {
/* The above call should not fail, and if it does, that does
* not mean the whole creation operation has failed. So
* report it the user for their convenience, but do not report
* it to the caller. */
warn_report_err(local_err);
}
out_close:
if (qemu_close(fd) != 0 && result == 0) {
result = -errno;
error_setg_errno(errp, -result, "Could not close the new file");
}
out:
return result;
}
static int coroutine_fn raw_co_create_opts(BlockDriver *drv,
const char *filename,
QemuOpts *opts,
Error **errp)
{
BlockdevCreateOptions options;
int64_t total_size = 0;
bool nocow = false;
PreallocMode prealloc;
char *buf = NULL;
Error *local_err = NULL;
/* Skip file: protocol prefix */
strstart(filename, "file:", &filename);
/* Read out options */
total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
BDRV_SECTOR_SIZE);
nocow = qemu_opt_get_bool(opts, BLOCK_OPT_NOCOW, false);
buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
prealloc = qapi_enum_parse(&PreallocMode_lookup, buf,
PREALLOC_MODE_OFF, &local_err);
g_free(buf);
if (local_err) {
error_propagate(errp, local_err);
return -EINVAL;
}
options = (BlockdevCreateOptions) {
.driver = BLOCKDEV_DRIVER_FILE,
.u.file = {
.filename = (char *) filename,
.size = total_size,
.has_preallocation = true,
.preallocation = prealloc,
.has_nocow = true,
.nocow = nocow,
},
};
return raw_co_create(&options, errp);
}
static int coroutine_fn raw_co_delete_file(BlockDriverState *bs,
Error **errp)
{
struct stat st;
int ret;
if (!(stat(bs->filename, &st) == 0) || !S_ISREG(st.st_mode)) {
error_setg_errno(errp, ENOENT, "%s is not a regular file",
bs->filename);
return -ENOENT;
}
ret = unlink(bs->filename);
if (ret < 0) {
ret = -errno;
error_setg_errno(errp, -ret, "Error when deleting file %s",
bs->filename);
}
return ret;
}
/*
* Find allocation range in @bs around offset @start.
* May change underlying file descriptor's file offset.
* If @start is not in a hole, store @start in @data, and the
* beginning of the next hole in @hole, and return 0.
* If @start is in a non-trailing hole, store @start in @hole and the
* beginning of the next non-hole in @data, and return 0.
* If @start is in a trailing hole or beyond EOF, return -ENXIO.
* If we can't find out, return a negative errno other than -ENXIO.
*/
static int find_allocation(BlockDriverState *bs, off_t start,
off_t *data, off_t *hole)
{
#if defined SEEK_HOLE && defined SEEK_DATA
BDRVRawState *s = bs->opaque;
off_t offs;
/*
* SEEK_DATA cases:
* D1. offs == start: start is in data
* D2. offs > start: start is in a hole, next data at offs
* D3. offs < 0, errno = ENXIO: either start is in a trailing hole
* or start is beyond EOF
* If the latter happens, the file has been truncated behind
* our back since we opened it. All bets are off then.
* Treating like a trailing hole is simplest.
* D4. offs < 0, errno != ENXIO: we learned nothing
*/
offs = lseek(s->fd, start, SEEK_DATA);
if (offs < 0) {
return -errno; /* D3 or D4 */
}
if (offs < start) {
/* This is not a valid return by lseek(). We are safe to just return
* -EIO in this case, and we'll treat it like D4. */
return -EIO;
}
if (offs > start) {
/* D2: in hole, next data at offs */
*hole = start;
*data = offs;
return 0;
}
/* D1: in data, end not yet known */
/*
* SEEK_HOLE cases:
* H1. offs == start: start is in a hole
* If this happens here, a hole has been dug behind our back
* since the previous lseek().
* H2. offs > start: either start is in data, next hole at offs,
* or start is in trailing hole, EOF at offs
* Linux treats trailing holes like any other hole: offs ==
* start. Solaris seeks to EOF instead: offs > start (blech).
* If that happens here, a hole has been dug behind our back
* since the previous lseek().
* H3. offs < 0, errno = ENXIO: start is beyond EOF
* If this happens, the file has been truncated behind our
* back since we opened it. Treat it like a trailing hole.
* H4. offs < 0, errno != ENXIO: we learned nothing
* Pretend we know nothing at all, i.e. "forget" about D1.
*/
offs = lseek(s->fd, start, SEEK_HOLE);
if (offs < 0) {
return -errno; /* D1 and (H3 or H4) */
}
if (offs < start) {
/* This is not a valid return by lseek(). We are safe to just return
* -EIO in this case, and we'll treat it like H4. */
return -EIO;
}
if (offs > start) {
/*
* D1 and H2: either in data, next hole at offs, or it was in
* data but is now in a trailing hole. In the latter case,
* all bets are off. Treating it as if it there was data all
* the way to EOF is safe, so simply do that.
*/
*data = start;
*hole = offs;
return 0;
}
/* D1 and H1 */
return -EBUSY;
#else
return -ENOTSUP;
#endif
}
/*
* Returns the allocation status of the specified offset.
*
* The block layer guarantees 'offset' and 'bytes' are within bounds.
*
* 'pnum' is set to the number of bytes (including and immediately following
* the specified offset) that are known to be in the same
* allocated/unallocated state.
*
* 'bytes' is the max value 'pnum' should be set to.
*/
static int coroutine_fn raw_co_block_status(BlockDriverState *bs,
bool want_zero,
int64_t offset,
int64_t bytes, int64_t *pnum,
int64_t *map,
BlockDriverState **file)
{
off_t data = 0, hole = 0;
int ret;
assert(QEMU_IS_ALIGNED(offset | bytes, bs->bl.request_alignment));
ret = fd_open(bs);
if (ret < 0) {
return ret;
}
if (!want_zero) {
*pnum = bytes;
*map = offset;
*file = bs;
return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
}
ret = find_allocation(bs, offset, &data, &hole);
if (ret == -ENXIO) {
/* Trailing hole */
*pnum = bytes;
ret = BDRV_BLOCK_ZERO;
} else if (ret < 0) {
/* No info available, so pretend there are no holes */
*pnum = bytes;
ret = BDRV_BLOCK_DATA;
} else if (data == offset) {
/* On a data extent, compute bytes to the end of the extent,
* possibly including a partial sector at EOF. */
*pnum = MIN(bytes, hole - offset);
/*
* We are not allowed to return partial sectors, though, so
* round up if necessary.
*/
if (!QEMU_IS_ALIGNED(*pnum, bs->bl.request_alignment)) {
int64_t file_length = raw_getlength(bs);
if (file_length > 0) {
/* Ignore errors, this is just a safeguard */
assert(hole == file_length);
}
*pnum = ROUND_UP(*pnum, bs->bl.request_alignment);
}
ret = BDRV_BLOCK_DATA;
} else {
/* On a hole, compute bytes to the beginning of the next extent. */
assert(hole == offset);
*pnum = MIN(bytes, data - offset);
ret = BDRV_BLOCK_ZERO;
}
*map = offset;
*file = bs;
return ret | BDRV_BLOCK_OFFSET_VALID;
}
#if defined(__linux__)
/* Verify that the file is not in the page cache */
static void check_cache_dropped(BlockDriverState *bs, Error **errp)
{
const size_t window_size = 128 * 1024 * 1024;
BDRVRawState *s = bs->opaque;
void *window = NULL;
size_t length = 0;
unsigned char *vec;
size_t page_size;
off_t offset;
off_t end;
/* mincore(2) page status information requires 1 byte per page */
page_size = sysconf(_SC_PAGESIZE);
vec = g_malloc(DIV_ROUND_UP(window_size, page_size));
end = raw_getlength(bs);
for (offset = 0; offset < end; offset += window_size) {
void *new_window;
size_t new_length;
size_t vec_end;
size_t i;
int ret;
/* Unmap previous window if size has changed */
new_length = MIN(end - offset, window_size);
if (new_length != length) {
munmap(window, length);
window = NULL;
length = 0;
}
new_window = mmap(window, new_length, PROT_NONE, MAP_PRIVATE,
s->fd, offset);
if (new_window == MAP_FAILED) {
error_setg_errno(errp, errno, "mmap failed");
break;
}
window = new_window;
length = new_length;
ret = mincore(window, length, vec);
if (ret < 0) {
error_setg_errno(errp, errno, "mincore failed");
break;
}
vec_end = DIV_ROUND_UP(length, page_size);
for (i = 0; i < vec_end; i++) {
if (vec[i] & 0x1) {
error_setg(errp, "page cache still in use!");
break;
}
}
}
if (window) {
munmap(window, length);
}
g_free(vec);
}
#endif /* __linux__ */
static void coroutine_fn raw_co_invalidate_cache(BlockDriverState *bs,
Error **errp)
{
BDRVRawState *s = bs->opaque;
int ret;
ret = fd_open(bs);
if (ret < 0) {
error_setg_errno(errp, -ret, "The file descriptor is not open");
return;
}
if (!s->drop_cache) {
return;
}
if (s->open_flags & O_DIRECT) {
return; /* No host kernel page cache */
}
#if defined(__linux__)
/* This sets the scene for the next syscall... */
ret = bdrv_co_flush(bs);
if (ret < 0) {
error_setg_errno(errp, -ret, "flush failed");
return;
}
/* Linux does not invalidate pages that are dirty, locked, or mmapped by a
* process. These limitations are okay because we just fsynced the file,
* we don't use mmap, and the file should not be in use by other processes.
*/
ret = posix_fadvise(s->fd, 0, 0, POSIX_FADV_DONTNEED);
if (ret != 0) { /* the return value is a positive errno */
error_setg_errno(errp, ret, "fadvise failed");
return;
}
if (s->check_cache_dropped) {
check_cache_dropped(bs, errp);
}
#else /* __linux__ */
/* Do nothing. Live migration to a remote host with cache.direct=off is
* unsupported on other host operating systems. Cache consistency issues
* may occur but no error is reported here, partly because that's the
* historical behavior and partly because it's hard to differentiate valid
* configurations that should not cause errors.
*/
#endif /* !__linux__ */
}
static void raw_account_discard(BDRVRawState *s, uint64_t nbytes, int ret)
{
if (ret) {
s->stats.discard_nb_failed++;
} else {
s->stats.discard_nb_ok++;
s->stats.discard_bytes_ok += nbytes;
}
}
static coroutine_fn int
raw_do_pdiscard(BlockDriverState *bs, int64_t offset, int bytes, bool blkdev)
{
BDRVRawState *s = bs->opaque;
RawPosixAIOData acb;
int ret;
acb = (RawPosixAIOData) {
.bs = bs,
.aio_fildes = s->fd,
.aio_type = QEMU_AIO_DISCARD,
.aio_offset = offset,
.aio_nbytes = bytes,
};
if (blkdev) {
acb.aio_type |= QEMU_AIO_BLKDEV;
}
ret = raw_thread_pool_submit(bs, handle_aiocb_discard, &acb);
raw_account_discard(s, bytes, ret);
return ret;
}
static coroutine_fn int
raw_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes)
{
return raw_do_pdiscard(bs, offset, bytes, false);
}
static int coroutine_fn
raw_do_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes,
BdrvRequestFlags flags, bool blkdev)
{
BDRVRawState *s = bs->opaque;
RawPosixAIOData acb;
ThreadPoolFunc *handler;
#ifdef CONFIG_FALLOCATE
if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) {
BdrvTrackedRequest *req;
uint64_t end;
/*
* This is a workaround for a bug in the Linux XFS driver,
* where writes submitted through the AIO interface will be
* discarded if they happen beyond a concurrently running
* fallocate() that increases the file length (i.e., both the
* write and the fallocate() happen beyond the EOF).
*
* To work around it, we extend the tracked request for this
* zero write until INT64_MAX (effectively infinity), and mark
* it as serializing.
*
* We have to enable this workaround for all filesystems and
* AIO modes (not just XFS with aio=native), because for
* remote filesystems we do not know the host configuration.
*/
req = bdrv_co_get_self_request(bs);
assert(req);
assert(req->type == BDRV_TRACKED_WRITE);
assert(req->offset <= offset);
assert(req->offset + req->bytes >= offset + bytes);
end = INT64_MAX & -(uint64_t)bs->bl.request_alignment;
req->bytes = end - req->offset;
req->overlap_bytes = req->bytes;
bdrv_mark_request_serialising(req, bs->bl.request_alignment);
}
#endif
acb = (RawPosixAIOData) {
.bs = bs,
.aio_fildes = s->fd,
.aio_type = QEMU_AIO_WRITE_ZEROES,
.aio_offset = offset,
.aio_nbytes = bytes,
};
if (blkdev) {
acb.aio_type |= QEMU_AIO_BLKDEV;
}
if (flags & BDRV_REQ_NO_FALLBACK) {
acb.aio_type |= QEMU_AIO_NO_FALLBACK;
}
if (flags & BDRV_REQ_MAY_UNMAP) {
acb.aio_type |= QEMU_AIO_DISCARD;
handler = handle_aiocb_write_zeroes_unmap;
} else {
handler = handle_aiocb_write_zeroes;
}
return raw_thread_pool_submit(bs, handler, &acb);
}
static int coroutine_fn raw_co_pwrite_zeroes(
BlockDriverState *bs, int64_t offset,
int bytes, BdrvRequestFlags flags)
{
return raw_do_pwrite_zeroes(bs, offset, bytes, flags, false);
}
static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BDRVRawState *s = bs->opaque;
bdi->unallocated_blocks_are_zero = s->discard_zeroes;
return 0;
}
static BlockStatsSpecificFile get_blockstats_specific_file(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
return (BlockStatsSpecificFile) {
.discard_nb_ok = s->stats.discard_nb_ok,
.discard_nb_failed = s->stats.discard_nb_failed,
.discard_bytes_ok = s->stats.discard_bytes_ok,
};
}
static BlockStatsSpecific *raw_get_specific_stats(BlockDriverState *bs)
{
BlockStatsSpecific *stats = g_new(BlockStatsSpecific, 1);
stats->driver = BLOCKDEV_DRIVER_FILE;
stats->u.file = get_blockstats_specific_file(bs);
return stats;
}
static BlockStatsSpecific *hdev_get_specific_stats(BlockDriverState *bs)
{
BlockStatsSpecific *stats = g_new(BlockStatsSpecific, 1);
stats->driver = BLOCKDEV_DRIVER_HOST_DEVICE;
stats->u.host_device = get_blockstats_specific_file(bs);
return stats;
}
static QemuOptsList raw_create_opts = {
.name = "raw-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
{
.name = BLOCK_OPT_NOCOW,
.type = QEMU_OPT_BOOL,
.help = "Turn off copy-on-write (valid only on btrfs)"
},
{
.name = BLOCK_OPT_PREALLOC,
.type = QEMU_OPT_STRING,
.help = "Preallocation mode (allowed values: off"
#ifdef CONFIG_POSIX_FALLOCATE
", falloc"
#endif
", full)"
},
{ /* end of list */ }
}
};
static int raw_check_perm(BlockDriverState *bs, uint64_t perm, uint64_t shared,
Error **errp)
{
BDRVRawState *s = bs->opaque;
BDRVRawReopenState *rs = NULL;
int open_flags;
int ret;
if (s->perm_change_fd) {
/*
* In the context of reopen, this function may be called several times
* (directly and recursively while change permissions of the parent).
* This is even true for children that don't inherit from the original
* reopen node, so s->reopen_state is not set.
*
* Ignore all but the first call.
*/
return 0;
}
if (s->reopen_state) {
/* We already have a new file descriptor to set permissions for */
assert(s->reopen_state->perm == perm);
assert(s->reopen_state->shared_perm == shared);
rs = s->reopen_state->opaque;
s->perm_change_fd = rs->fd;
s->perm_change_flags = rs->open_flags;
} else {
/* We may need a new fd if auto-read-only switches the mode */
ret = raw_reconfigure_getfd(bs, bs->open_flags, &open_flags, perm,
false, errp);
if (ret < 0) {
return ret;
} else if (ret != s->fd) {
s->perm_change_fd = ret;
s->perm_change_flags = open_flags;
}
}
/* Prepare permissions on old fd to avoid conflicts between old and new,
* but keep everything locked that new will need. */
ret = raw_handle_perm_lock(bs, RAW_PL_PREPARE, perm, shared, errp);
if (ret < 0) {
goto fail;
}
/* Copy locks to the new fd */
if (s->perm_change_fd) {
ret = raw_apply_lock_bytes(NULL, s->perm_change_fd, perm, ~shared,
false, errp);
if (ret < 0) {
raw_handle_perm_lock(bs, RAW_PL_ABORT, 0, 0, NULL);
goto fail;
}
}
return 0;
fail:
if (s->perm_change_fd && !s->reopen_state) {
qemu_close(s->perm_change_fd);
}
s->perm_change_fd = 0;
return ret;
}
static void raw_set_perm(BlockDriverState *bs, uint64_t perm, uint64_t shared)
{
BDRVRawState *s = bs->opaque;
/* For reopen, we have already switched to the new fd (.bdrv_set_perm is
* called after .bdrv_reopen_commit) */
if (s->perm_change_fd && s->fd != s->perm_change_fd) {
qemu_close(s->fd);
s->fd = s->perm_change_fd;
s->open_flags = s->perm_change_flags;
}
s->perm_change_fd = 0;
raw_handle_perm_lock(bs, RAW_PL_COMMIT, perm, shared, NULL);
s->perm = perm;
s->shared_perm = shared;
}
static void raw_abort_perm_update(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
/* For reopen, .bdrv_reopen_abort is called afterwards and will close
* the file descriptor. */
if (s->perm_change_fd && !s->reopen_state) {
qemu_close(s->perm_change_fd);
}
s->perm_change_fd = 0;
raw_handle_perm_lock(bs, RAW_PL_ABORT, 0, 0, NULL);
}
static int coroutine_fn raw_co_copy_range_from(
BlockDriverState *bs, BdrvChild *src, uint64_t src_offset,
BdrvChild *dst, uint64_t dst_offset, uint64_t bytes,
BdrvRequestFlags read_flags, BdrvRequestFlags write_flags)
{
return bdrv_co_copy_range_to(src, src_offset, dst, dst_offset, bytes,
read_flags, write_flags);
}
static int coroutine_fn raw_co_copy_range_to(BlockDriverState *bs,
BdrvChild