Am 07.08.2017 um 22:30 hat Eric Blake geschrieben: > This also requires changing the return type of get_cluster_offset() > and adjusting all callers. > > Use osdep.h macros instead of open-coded rounding while in the > area. > > Reported-by: Markus Armbruster <arm...@redhat.com> > Signed-off-by: Eric Blake <ebl...@redhat.com> > --- > block/qcow.c | 64 > ++++++++++++++++++++++++++++++++++++++++++------------------ > 1 file changed, 45 insertions(+), 19 deletions(-) > > diff --git a/block/qcow.c b/block/qcow.c > index c08cdc4a7b..937023d447 100644 > --- a/block/qcow.c > +++ b/block/qcow.c > @@ -347,16 +347,17 @@ static int qcow_reopen_prepare(BDRVReopenState *state, > * 'compressed_size'. 'compressed_size' must be > 0 and < > * cluster_size > * > - * return 0 if not allocated. > + * return 0 if not allocated, -errno on failure. > */ > -static uint64_t get_cluster_offset(BlockDriverState *bs, > - uint64_t offset, int allocate, > - int compressed_size, > - int n_start, int n_end) > +static int64_t get_cluster_offset(BlockDriverState *bs, > + uint64_t offset, int allocate, > + int compressed_size, > + int n_start, int n_end)
qcow2 ended up with this prototype: int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, unsigned int *bytes, uint64_t *cluster_offset) Separating a full uin64_t offset by-reference parameter and an 0/-errno status return code feels a little cleaner to me. And in fact, it's not only cleaner, but bit 63 is QCOW_OFLAG_COMPRESSED, so this patch breaks compressed images. > { > BDRVQcowState *s = bs->opaque; > int min_index, i, j, l1_index, l2_index; > - uint64_t l2_offset, *l2_table, cluster_offset, tmp; > + int64_t l2_offset, cluster_offset; > + uint64_t *l2_table, tmp; > uint32_t min_count; > int new_l2_table; > > @@ -368,8 +369,11 @@ static uint64_t get_cluster_offset(BlockDriverState *bs, > return 0; > /* allocate a new l2 entry */ > l2_offset = bdrv_getlength(bs->file->bs); > + if (l2_offset < 0) { > + return l2_offset; > + } > /* round to cluster size */ > - l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - > 1); > + l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size); > /* update the L1 entry */ > s->l1_table[l1_index] = l2_offset; > tmp = cpu_to_be64(l2_offset); > @@ -430,8 +434,10 @@ static uint64_t get_cluster_offset(BlockDriverState *bs, > if (decompress_cluster(bs, cluster_offset) < 0) > return 0; > cluster_offset = bdrv_getlength(bs->file->bs); > - cluster_offset = (cluster_offset + s->cluster_size - 1) & > - ~(s->cluster_size - 1); > + if (cluster_offset < 0) { > + return cluster_offset; > + } > + cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); > /* write the cluster content */ > if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, > s->cluster_size) != > @@ -439,12 +445,19 @@ static uint64_t get_cluster_offset(BlockDriverState *bs, > return -1; > } else { > cluster_offset = bdrv_getlength(bs->file->bs); > + if (cluster_offset < 0) { > + return cluster_offset; > + } > if (allocate == 1) { > + int ret; > + > /* round to cluster size */ > - cluster_offset = (cluster_offset + s->cluster_size - 1) & > - ~(s->cluster_size - 1); > - bdrv_truncate(bs->file, cluster_offset + s->cluster_size, > - PREALLOC_MODE_OFF, NULL); > + cluster_offset = QEMU_ALIGN_UP(cluster_offset, > s->cluster_size); > + ret = bdrv_truncate(bs->file, cluster_offset + > s->cluster_size, > + PREALLOC_MODE_OFF, NULL); > + if (ret < 0) { > + return ret; > + } > /* if encrypted, we must initialize the cluster > content which won't be written */ > if (bs->encrypted && > @@ -491,11 +504,14 @@ static int64_t coroutine_fn > qcow_co_get_block_status(BlockDriverState *bs, > { > BDRVQcowState *s = bs->opaque; > int index_in_cluster, n; > - uint64_t cluster_offset; > + int64_t cluster_offset; > > qemu_co_mutex_lock(&s->lock); > cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); > qemu_co_mutex_unlock(&s->lock); > + if (cluster_offset < 0) { > + return cluster_offset; > + } > index_in_cluster = sector_num & (s->cluster_sectors - 1); > n = s->cluster_sectors - index_in_cluster; > if (n > nb_sectors) > @@ -567,7 +583,7 @@ static coroutine_fn int qcow_co_readv(BlockDriverState > *bs, int64_t sector_num, > BDRVQcowState *s = bs->opaque; > int index_in_cluster; > int ret = 0, n; > - uint64_t cluster_offset; > + int64_t cluster_offset; > struct iovec hd_iov; > QEMUIOVector hd_qiov; > uint8_t *buf; > @@ -588,8 +604,10 @@ static coroutine_fn int qcow_co_readv(BlockDriverState > *bs, int64_t sector_num, > > while (nb_sectors != 0) { > /* prepare next request */ > - cluster_offset = get_cluster_offset(bs, sector_num << 9, > - 0, 0, 0, 0); > + cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); > + if (cluster_offset < 0) { > + return cluster_offset; > + } Oops, we're still holding s->lock. Combined with the bug that compressed clusters are treated as errors now, this makes compressed images result in an assertion failure: qemu-system-x86_64: util/qemu-coroutine.c:138: qemu_aio_coroutine_enter: Assertion `!co->locks_held' failed. > index_in_cluster = sector_num & (s->cluster_sectors - 1); > n = s->cluster_sectors - index_in_cluster; > if (n > nb_sectors) { Kevin