From: Kevin Wolf Date: Fri, 27 Oct 2023 15:53:15 +0000 (+0200) Subject: block: Mark bdrv_filter_or_cow_bs() and callers GRAPH_RDLOCK X-Git-Tag: v8.2.0~61^2~19 X-Git-Url: https://git.proxmox.com/?p=mirror_qemu.git;a=commitdiff_plain;h=372b69f503d47eb6619a98cac2ab5a6a569e3483 block: Mark bdrv_filter_or_cow_bs() and callers GRAPH_RDLOCK This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_filter_or_cow_bs() need to hold a reader lock for the graph because it calls bdrv_filter_or_cow_child(), which accesses bs->file/backing. Signed-off-by: Kevin Wolf Message-ID: <20231027155333.420094-7-kwolf@redhat.com> Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- diff --git a/block.c b/block.c index 5f92eb4950..a6060eddbc 100644 --- a/block.c +++ b/block.c @@ -5435,17 +5435,6 @@ static int bdrv_replace_node_common(BlockDriverState *from, GLOBAL_STATE_CODE(); - if (detach_subchain) { - assert(bdrv_chain_contains(from, to)); - assert(from != to); - for (to_cow_parent = from; - bdrv_filter_or_cow_bs(to_cow_parent) != to; - to_cow_parent = bdrv_filter_or_cow_bs(to_cow_parent)) - { - ; - } - } - /* Make sure that @from doesn't go away until we have successfully attached * all of its parents to @to. */ bdrv_ref(from); @@ -5457,6 +5446,17 @@ static int bdrv_replace_node_common(BlockDriverState *from, bdrv_graph_wrlock(to); + if (detach_subchain) { + assert(bdrv_chain_contains(from, to)); + assert(from != to); + for (to_cow_parent = from; + bdrv_filter_or_cow_bs(to_cow_parent) != to; + to_cow_parent = bdrv_filter_or_cow_bs(to_cow_parent)) + { + ; + } + } + /* * Do the replacement without permission update. * Replacement may influence the permissions, we should calculate new @@ -5504,10 +5504,14 @@ int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, int bdrv_drop_filter(BlockDriverState *bs, Error **errp) { + BlockDriverState *child_bs; + GLOBAL_STATE_CODE(); + bdrv_graph_rdlock_main_loop(); + child_bs = bdrv_filter_or_cow_bs(bs); + bdrv_graph_rdunlock_main_loop(); - return bdrv_replace_node_common(bs, bdrv_filter_or_cow_bs(bs), true, true, - errp); + return bdrv_replace_node_common(bs, child_bs, true, true, errp); } /* @@ -6509,6 +6513,7 @@ bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base) { GLOBAL_STATE_CODE(); + GRAPH_RDLOCK_GUARD_MAINLOOP(); while (top && top != base) { top = bdrv_filter_or_cow_bs(top); diff --git a/block/stream.c b/block/stream.c index 51333e460b..2781441191 100644 --- a/block/stream.c +++ b/block/stream.c @@ -60,6 +60,8 @@ static int stream_prepare(Job *job) Error *local_err = NULL; int ret = 0; + GLOBAL_STATE_CODE(); + /* We should drop filter at this point, as filter hold the backing chain */ bdrv_cor_filter_drop(s->cor_filter_bs); s->cor_filter_bs = NULL; @@ -78,8 +80,10 @@ static int stream_prepare(Job *job) bdrv_drained_begin(unfiltered_bs_cow); } + bdrv_graph_rdlock_main_loop(); base = bdrv_filter_or_cow_bs(s->above_base); unfiltered_base = bdrv_skip_filters(base); + bdrv_graph_rdunlock_main_loop(); if (bdrv_cow_child(unfiltered_bs)) { const char *base_id = NULL, *base_fmt = NULL; diff --git a/blockdev.c b/blockdev.c index 148df99e00..4cb8e1d91a 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2501,8 +2501,8 @@ void qmp_block_stream(const char *job_id, const char *device, /* * Check for op blockers in the whole chain between bs and base (or bottom) */ - iter_end = bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs; bdrv_graph_rdlock_main_loop(); + iter_end = bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs; for (iter = bs; iter && iter != iter_end; iter = bdrv_filter_or_cow_bs(iter)) { diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h index 26bff94e4e..6800af7590 100644 --- a/include/block/block_int-io.h +++ b/include/block/block_int-io.h @@ -150,7 +150,8 @@ bdrv_filter_bs(BlockDriverState *bs) return child_bs(bdrv_filter_child(bs)); } -static inline BlockDriverState *bdrv_filter_or_cow_bs(BlockDriverState *bs) +static inline BlockDriverState * GRAPH_RDLOCK +bdrv_filter_or_cow_bs(BlockDriverState *bs) { IO_CODE(); return child_bs(bdrv_filter_or_cow_child(bs)); diff --git a/nbd/server.c b/nbd/server.c index 859c163d19..895cf0a752 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1689,6 +1689,7 @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, size_t i; int ret; + GLOBAL_STATE_CODE(); assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); if (!nbd_server_is_running()) { @@ -1743,6 +1744,8 @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, } exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); + bdrv_graph_rdlock_main_loop(); + for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) { exp->nr_export_bitmaps++; } @@ -1825,9 +1828,12 @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, QTAILQ_INSERT_TAIL(&exports, exp, next); + bdrv_graph_rdunlock_main_loop(); + return 0; fail: + bdrv_graph_rdunlock_main_loop(); g_free(exp->export_bitmaps); g_free(exp->name); g_free(exp->description);