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raw-posix: Fail gracefully if no working alignment is found

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If qemu couldn't find out what O_DIRECT alignment to use with a given
file, it would run into assert(bdrv_opt_mem_align(bs) != 0); in block.c
and confuse users. This adds a more descriptive error message for such
cases.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Kevin Wolf 2014-07-16 17:48:17 +02:00 committed by Stefan Hajnoczi
parent 3baca89139
commit df26a35025
1 changed files with 27 additions and 8 deletions
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35
block/raw-posix.c
View file

@ -221,7 +221,7 @@ static int raw_normalize_devicepath(const char **filename)
}
#endif
static void raw_probe_alignment(BlockDriverState *bs)
static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp)
{
BDRVRawState *s = bs->opaque;
char *buf;
@ -240,24 +240,24 @@ static void raw_probe_alignment(BlockDriverState *bs)
s->buf_align = 0;
#ifdef BLKSSZGET
if (ioctl(s->fd, BLKSSZGET, &sector_size) >= 0) {
if (ioctl(fd, BLKSSZGET, &sector_size) >= 0) {
bs->request_alignment = sector_size;
}
#endif
#ifdef DKIOCGETBLOCKSIZE
if (ioctl(s->fd, DKIOCGETBLOCKSIZE, &sector_size) >= 0) {
if (ioctl(fd, DKIOCGETBLOCKSIZE, &sector_size) >= 0) {
bs->request_alignment = sector_size;
}
#endif
#ifdef DIOCGSECTORSIZE
if (ioctl(s->fd, DIOCGSECTORSIZE, &sector_size) >= 0) {
if (ioctl(fd, DIOCGSECTORSIZE, &sector_size) >= 0) {
bs->request_alignment = sector_size;
}
#endif
#ifdef CONFIG_XFS
if (s->is_xfs) {
struct dioattr da;
if (xfsctl(NULL, s->fd, XFS_IOC_DIOINFO, &da) >= 0) {
if (xfsctl(NULL, fd, XFS_IOC_DIOINFO, &da) >= 0) {
bs->request_alignment = da.d_miniosz;
/* The kernel returns wrong information for d_mem */
/* s->buf_align = da.d_mem; */
@ -270,7 +270,7 @@ static void raw_probe_alignment(BlockDriverState *bs)
size_t align;
buf = qemu_memalign(MAX_BLOCKSIZE, 2 * MAX_BLOCKSIZE);
for (align = 512; align <= MAX_BLOCKSIZE; align <<= 1) {
if (pread(s->fd, buf + align, MAX_BLOCKSIZE, 0) >= 0) {
if (pread(fd, buf + align, MAX_BLOCKSIZE, 0) >= 0) {
s->buf_align = align;
break;
}
@ -282,13 +282,18 @@ static void raw_probe_alignment(BlockDriverState *bs)
size_t align;
buf = qemu_memalign(s->buf_align, MAX_BLOCKSIZE);
for (align = 512; align <= MAX_BLOCKSIZE; align <<= 1) {
if (pread(s->fd, buf, align, 0) >= 0) {
if (pread(fd, buf, align, 0) >= 0) {
bs->request_alignment = align;
break;
}
}
qemu_vfree(buf);
}
if (!s->buf_align || !bs->request_alignment) {
error_setg(errp, "Could not find working O_DIRECT alignment. "
"Try cache.direct=off.");
}
}
static void raw_parse_flags(int bdrv_flags, int *open_flags)
@ -505,6 +510,7 @@ static int raw_reopen_prepare(BDRVReopenState *state,
BDRVRawState *s;
BDRVRawReopenState *raw_s;
int ret = 0;
Error *local_err = NULL;
assert(state != NULL);
assert(state->bs != NULL);
@ -577,6 +583,19 @@ static int raw_reopen_prepare(BDRVReopenState *state,
ret = -1;
}
}
/* Fail already reopen_prepare() if we can't get a working O_DIRECT
* alignment with the new fd. */
if (raw_s->fd != -1) {
raw_probe_alignment(state->bs, raw_s->fd, &local_err);
if (local_err) {
qemu_close(raw_s->fd);
raw_s->fd = -1;
error_propagate(errp, local_err);
ret = -EINVAL;
}
}
return ret;
}
@ -619,7 +638,7 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
{
BDRVRawState *s = bs->opaque;
raw_probe_alignment(bs);
raw_probe_alignment(bs, s->fd, errp);
bs->bl.opt_mem_alignment = s->buf_align;
}