aboutsummaryrefslogtreecommitdiff
path: root/block/vhdx.c
diff options
context:
space:
mode:
Diffstat (limited to 'block/vhdx.c')
-rw-r--r--block/vhdx.c212
1 files changed, 208 insertions, 4 deletions
diff --git a/block/vhdx.c b/block/vhdx.c
index 574ac4c931..050f0719c8 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -914,7 +914,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
if (payblocks--) {
/* payload bat entries */
if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
- PAYLOAD_BLOCK_FULL_PRESENT) {
+ PAYLOAD_BLOCK_FULLY_PRESENT) {
ret = vhdx_region_check(s, s->bat[i] & VHDX_BAT_FILE_OFF_MASK,
s->block_size);
if (ret < 0) {
@@ -935,7 +935,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
}
}
- /* TODO: differencing files, write */
+ /* TODO: differencing files */
/* Disable migration when VHDX images are used */
error_set(&s->migration_blocker,
@@ -1040,7 +1040,7 @@ static coroutine_fn int vhdx_co_readv(BlockDriverState *bs, int64_t sector_num,
/* return zero */
qemu_iovec_memset(&hd_qiov, 0, 0, sinfo.bytes_avail);
break;
- case PAYLOAD_BLOCK_FULL_PRESENT:
+ case PAYLOAD_BLOCK_FULLY_PRESENT:
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_readv(bs->file,
sinfo.file_offset >> BDRV_SECTOR_BITS,
@@ -1070,7 +1070,43 @@ exit:
return ret;
}
+/*
+ * Allocate a new payload block at the end of the file.
+ *
+ * Allocation will happen at 1MB alignment inside the file
+ *
+ * Returns the file offset start of the new payload block
+ */
+static int vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
+ uint64_t *new_offset)
+{
+ *new_offset = bdrv_getlength(bs->file);
+
+ /* per the spec, the address for a block is in units of 1MB */
+ *new_offset = ROUND_UP(*new_offset, 1024 * 1024);
+
+ return bdrv_truncate(bs->file, *new_offset + s->block_size);
+}
+
+/*
+ * Update the BAT table entry with the new file offset, and the new entry
+ * state */
+static void vhdx_update_bat_table_entry(BlockDriverState *bs, BDRVVHDXState *s,
+ VHDXSectorInfo *sinfo,
+ uint64_t *bat_entry_le,
+ uint64_t *bat_offset, int state)
+{
+ /* The BAT entry is a uint64, with 44 bits for the file offset in units of
+ * 1MB, and 3 bits for the block state. */
+ s->bat[sinfo->bat_idx] = ((sinfo->file_offset>>20) <<
+ VHDX_BAT_FILE_OFF_BITS);
+ s->bat[sinfo->bat_idx] |= state & VHDX_BAT_STATE_BIT_MASK;
+
+ *bat_entry_le = cpu_to_le64(s->bat[sinfo->bat_idx]);
+ *bat_offset = s->bat_offset + sinfo->bat_idx * sizeof(VHDXBatEntry);
+
+}
/* Per the spec, on the first write of guest-visible data to the file the
* data write guid must be updated in the header */
@@ -1087,7 +1123,175 @@ int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
- return -ENOTSUP;
+ int ret = -ENOTSUP;
+ BDRVVHDXState *s = bs->opaque;
+ VHDXSectorInfo sinfo;
+ uint64_t bytes_done = 0;
+ uint64_t bat_entry = 0;
+ uint64_t bat_entry_offset = 0;
+ QEMUIOVector hd_qiov;
+ struct iovec iov1 = { 0 };
+ struct iovec iov2 = { 0 };
+ int sectors_to_write;
+ int bat_state;
+ uint64_t bat_prior_offset = 0;
+ bool bat_update = false;
+
+ qemu_iovec_init(&hd_qiov, qiov->niov);
+
+ qemu_co_mutex_lock(&s->lock);
+
+ ret = vhdx_user_visible_write(bs, s);
+ if (ret < 0) {
+ goto exit;
+ }
+
+ while (nb_sectors > 0) {
+ bool use_zero_buffers = false;
+ bat_update = false;
+ if (s->params.data_bits & VHDX_PARAMS_HAS_PARENT) {
+ /* not supported yet */
+ ret = -ENOTSUP;
+ goto exit;
+ } else {
+ vhdx_block_translate(s, sector_num, nb_sectors, &sinfo);
+ sectors_to_write = sinfo.sectors_avail;
+
+ qemu_iovec_reset(&hd_qiov);
+ /* check the payload block state */
+ bat_state = s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK;
+ switch (bat_state) {
+ case PAYLOAD_BLOCK_ZERO:
+ /* in this case, we need to preserve zero writes for
+ * data that is not part of this write, so we must pad
+ * the rest of the buffer to zeroes */
+
+ /* if we are on a posix system with ftruncate() that extends
+ * a file, then it is zero-filled for us. On Win32, the raw
+ * layer uses SetFilePointer and SetFileEnd, which does not
+ * zero fill AFAIK */
+
+ /* Queue another write of zero buffers if the underlying file
+ * does not zero-fill on file extension */
+
+ if (bdrv_has_zero_init(bs->file) == 0) {
+ use_zero_buffers = true;
+
+ /* zero fill the front, if any */
+ if (sinfo.block_offset) {
+ iov1.iov_len = sinfo.block_offset;
+ iov1.iov_base = qemu_blockalign(bs, iov1.iov_len);
+ memset(iov1.iov_base, 0, iov1.iov_len);
+ qemu_iovec_concat_iov(&hd_qiov, &iov1, 1, 0,
+ sinfo.block_offset);
+ sectors_to_write += iov1.iov_len >> BDRV_SECTOR_BITS;
+ }
+
+ /* our actual data */
+ qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
+ sinfo.bytes_avail);
+
+ /* zero fill the back, if any */
+ if ((sinfo.bytes_avail - sinfo.block_offset) <
+ s->block_size) {
+ iov2.iov_len = s->block_size -
+ (sinfo.bytes_avail + sinfo.block_offset);
+ iov2.iov_base = qemu_blockalign(bs, iov2.iov_len);
+ memset(iov2.iov_base, 0, iov2.iov_len);
+ qemu_iovec_concat_iov(&hd_qiov, &iov2, 1, 0,
+ sinfo.block_offset);
+ sectors_to_write += iov2.iov_len >> BDRV_SECTOR_BITS;
+ }
+ }
+
+ /* fall through */
+ case PAYLOAD_BLOCK_NOT_PRESENT: /* fall through */
+ case PAYLOAD_BLOCK_UNMAPPED: /* fall through */
+ case PAYLOAD_BLOCK_UNDEFINED: /* fall through */
+ bat_prior_offset = sinfo.file_offset;
+ ret = vhdx_allocate_block(bs, s, &sinfo.file_offset);
+ if (ret < 0) {
+ goto exit;
+ }
+ /* once we support differencing files, this may also be
+ * partially present */
+ /* update block state to the newly specified state */
+ vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
+ &bat_entry_offset,
+ PAYLOAD_BLOCK_FULLY_PRESENT);
+ bat_update = true;
+ /* since we just allocated a block, file_offset is the
+ * beginning of the payload block. It needs to be the
+ * write address, which includes the offset into the block */
+ if (!use_zero_buffers) {
+ sinfo.file_offset += sinfo.block_offset;
+ }
+ /* fall through */
+ case PAYLOAD_BLOCK_FULLY_PRESENT:
+ /* if the file offset address is in the header zone,
+ * there is a problem */
+ if (sinfo.file_offset < (1024 * 1024)) {
+ ret = -EFAULT;
+ goto error_bat_restore;
+ }
+
+ if (!use_zero_buffers) {
+ qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
+ sinfo.bytes_avail);
+ }
+ /* block exists, so we can just overwrite it */
+ qemu_co_mutex_unlock(&s->lock);
+ ret = bdrv_co_writev(bs->file,
+ sinfo.file_offset >> BDRV_SECTOR_BITS,
+ sectors_to_write, &hd_qiov);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ goto error_bat_restore;
+ }
+ break;
+ case PAYLOAD_BLOCK_PARTIALLY_PRESENT:
+ /* we don't yet support difference files, fall through
+ * to error */
+ default:
+ ret = -EIO;
+ goto exit;
+ break;
+ }
+
+ if (bat_update) {
+ /* this will update the BAT entry into the log journal, and
+ * then flush the log journal out to disk */
+ ret = vhdx_log_write_and_flush(bs, s, &bat_entry,
+ sizeof(VHDXBatEntry),
+ bat_entry_offset);
+ if (ret < 0) {
+ goto exit;
+ }
+ }
+
+ nb_sectors -= sinfo.sectors_avail;
+ sector_num += sinfo.sectors_avail;
+ bytes_done += sinfo.bytes_avail;
+
+ }
+ }
+
+ goto exit;
+
+error_bat_restore:
+ if (bat_update) {
+ /* keep metadata in sync, and restore the bat entry state
+ * if error. */
+ sinfo.file_offset = bat_prior_offset;
+ vhdx_update_bat_table_entry(bs, s, &sinfo, &bat_entry,
+ &bat_entry_offset, bat_state);
+ }
+exit:
+ qemu_vfree(iov1.iov_base);
+ qemu_vfree(iov2.iov_base);
+ qemu_co_mutex_unlock(&s->lock);
+ qemu_iovec_destroy(&hd_qiov);
+ return ret;
}
generated by cgit v1.2.3 (git 2.26.2) at 2024-12-21 01:18:38 +0000