block: Set request_alignment during .bdrv_refresh_limits()

We want to eventually stick request_alignment alongside other
BlockLimits, but first, we must ensure it is populated at the
same time as all other limits, rather than being a special case
that is set only when a block is first opened.

Add a .bdrv_refresh_limits() to all four of our legacy devices
that will always be sector-only (bochs, cloop, dmg, vvfat), in
spite of their recent conversion to expose a byte interface.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/bochs.c

@@ -105,7 +105,6 @@ static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
     int ret;
 
     bs->read_only = 1; // no write support yet
-    bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
 
     ret = bdrv_pread(bs->file->bs, 0, &bochs, sizeof(bochs));
     if (ret < 0) {
@@ -189,6 +188,11 @@ fail:
     return ret;
 }
 
+static void bochs_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+    bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
+}
+
 static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
 {
     BDRVBochsState *s = bs->opaque;
@@ -283,6 +287,7 @@ static BlockDriver bdrv_bochs = {
     .instance_size	= sizeof(BDRVBochsState),
     .bdrv_probe		= bochs_probe,
     .bdrv_open		= bochs_open,
+    .bdrv_refresh_limits = bochs_refresh_limits,
     .bdrv_co_preadv = bochs_co_preadv,
     .bdrv_close		= bochs_close,
 };

block/cloop.c

@@ -67,7 +67,6 @@ static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
     int ret;
 
     bs->read_only = 1;
-    bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
 
     /* read header */
     ret = bdrv_pread(bs->file->bs, 128, &s->block_size, 4);
@@ -199,6 +198,11 @@ fail:
     return ret;
 }
 
+static void cloop_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+    bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
+}
+
 static inline int cloop_read_block(BlockDriverState *bs, int block_num)
 {
     BDRVCloopState *s = bs->opaque;
@@ -280,6 +284,7 @@ static BlockDriver bdrv_cloop = {
     .instance_size  = sizeof(BDRVCloopState),
     .bdrv_probe     = cloop_probe,
     .bdrv_open      = cloop_open,
+    .bdrv_refresh_limits = cloop_refresh_limits,
     .bdrv_co_preadv = cloop_co_preadv,
     .bdrv_close     = cloop_close,
 };

block/dmg.c

@@ -439,7 +439,6 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
     int ret;
 
     bs->read_only = 1;
-    bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
 
     s->n_chunks = 0;
     s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
@@ -547,6 +546,11 @@ fail:
     return ret;
 }
 
+static void dmg_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+    bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
+}
+
 static inline int is_sector_in_chunk(BDRVDMGState* s,
                 uint32_t chunk_num, uint64_t sector_num)
 {
@@ -720,6 +724,7 @@ static BlockDriver bdrv_dmg = {
     .instance_size  = sizeof(BDRVDMGState),
     .bdrv_probe     = dmg_probe,
     .bdrv_open      = dmg_open,
+    .bdrv_refresh_limits = dmg_refresh_limits,
     .bdrv_co_preadv = dmg_co_preadv,
     .bdrv_close     = dmg_close,
 };

block/vvfat.c

@@ -1177,7 +1177,6 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
         bs->read_only = 0;
     }
 
-    bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
     bs->total_sectors = cyls * heads * secs;
 
     if (init_directories(s, dirname, heads, secs, errp)) {
@@ -1209,6 +1208,11 @@ fail:
     return ret;
 }
 
+static void vvfat_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+    bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
+}
+
 static inline void vvfat_close_current_file(BDRVVVFATState *s)
 {
     if(s->current_mapping) {
@@ -3046,6 +3050,7 @@ static BlockDriver bdrv_vvfat = {
 
     .bdrv_parse_filename    = vvfat_parse_filename,
     .bdrv_file_open         = vvfat_open,
+    .bdrv_refresh_limits    = vvfat_refresh_limits,
     .bdrv_close             = vvfat_close,
 
     .bdrv_co_preadv         = vvfat_co_preadv,