From 277f2007ce187a6ff467579cb016824f80a2be10 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 29 Sep 2023 16:51:52 +0200 Subject: [PATCH] block: Mark bdrv_op_is_blocked() and callers GRAPH_RDLOCK This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_op_is_blocked() need to hold a reader lock for the graph because it calls bdrv_get_device_or_node_name(), which accesses the parents list of a node. Signed-off-by: Kevin Wolf Message-ID: <20230929145157.45443-18-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block.c | 2 -- block/block-backend.c | 1 + block/commit.c | 1 + block/monitor/block-hmp-cmds.c | 3 +++ block/qapi-sysemu.c | 9 +++++++-- blockdev.c | 15 +++++++++++++++ include/block/block-global-state.h | 4 +++- 7 files changed, 30 insertions(+), 5 deletions(-) diff --git a/block.c b/block.c index d1a3466069..fd348f5069 100644 --- a/block.c +++ b/block.c @@ -7251,8 +7251,6 @@ bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp) BdrvOpBlocker *blocker; GLOBAL_STATE_CODE(); - assume_graph_lock(); /* FIXME */ - assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); if (!QLIST_EMPTY(&bs->op_blockers[op])) { blocker = QLIST_FIRST(&bs->op_blockers[op]); diff --git a/block/block-backend.c b/block/block-backend.c index fd10fcc2d0..39aac1bbce 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -2388,6 +2388,7 @@ bool blk_op_is_blocked(BlockBackend *blk, BlockOpType op, Error **errp) { BlockDriverState *bs = blk_bs(blk); GLOBAL_STATE_CODE(); + GRAPH_RDLOCK_GUARD_MAINLOOP(); if (!bs) { return false; diff --git a/block/commit.c b/block/commit.c index aa45beb0f0..43d1de7577 100644 --- a/block/commit.c +++ b/block/commit.c @@ -434,6 +434,7 @@ int bdrv_commit(BlockDriverState *bs) Error *local_err = NULL; GLOBAL_STATE_CODE(); + GRAPH_RDLOCK_GUARD_MAINLOOP(); if (!drv) return -ENOMEDIUM; diff --git a/block/monitor/block-hmp-cmds.c b/block/monitor/block-hmp-cmds.c index 6b7d7dd072..7645c7e5fb 100644 --- a/block/monitor/block-hmp-cmds.c +++ b/block/monitor/block-hmp-cmds.c @@ -144,6 +144,9 @@ void hmp_drive_del(Monitor *mon, const QDict *qdict) AioContext *aio_context; Error *local_err = NULL; + GLOBAL_STATE_CODE(); + GRAPH_RDLOCK_GUARD_MAINLOOP(); + bs = bdrv_find_node(id); if (bs) { qmp_blockdev_del(id, &local_err); diff --git a/block/qapi-sysemu.c b/block/qapi-sysemu.c index e885a64c32..3f614cbc04 100644 --- a/block/qapi-sysemu.c +++ b/block/qapi-sysemu.c @@ -169,14 +169,16 @@ void qmp_blockdev_close_tray(const char *device, } } -static void blockdev_remove_medium(const char *device, const char *id, - Error **errp) +static void GRAPH_UNLOCKED +blockdev_remove_medium(const char *device, const char *id, Error **errp) { BlockBackend *blk; BlockDriverState *bs; AioContext *aio_context; bool has_attached_device; + GLOBAL_STATE_CODE(); + blk = qmp_get_blk(device, id, errp); if (!blk) { return; @@ -205,9 +207,12 @@ static void blockdev_remove_medium(const char *device, const char *id, aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); + bdrv_graph_rdlock_main_loop(); if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_EJECT, errp)) { + bdrv_graph_rdunlock_main_loop(); goto out; } + bdrv_graph_rdunlock_main_loop(); blk_remove_bs(blk); diff --git a/blockdev.c b/blockdev.c index 51c58dd432..a01c62596b 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1696,9 +1696,12 @@ static void drive_backup_action(DriveBackup *backup, } /* Early check to avoid creating target */ + bdrv_graph_rdlock_main_loop(); if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) { + bdrv_graph_rdunlock_main_loop(); goto out; } + bdrv_graph_rdunlock_main_loop(); flags = bs->open_flags | BDRV_O_RDWR; @@ -2360,10 +2363,13 @@ void coroutine_fn qmp_block_resize(const char *device, const char *node_name, return; } + bdrv_graph_co_rdlock(); if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_RESIZE, NULL)) { error_setg(errp, QERR_DEVICE_IN_USE, device); + bdrv_graph_co_rdunlock(); return; } + bdrv_graph_co_rdunlock(); blk = blk_co_new_with_bs(bs, BLK_PERM_RESIZE, BLK_PERM_ALL, errp); if (!blk) { @@ -2487,13 +2493,16 @@ 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(); for (iter = bs; iter && iter != iter_end; iter = bdrv_filter_or_cow_bs(iter)) { if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_STREAM, errp)) { + bdrv_graph_rdunlock_main_loop(); goto out; } } + bdrv_graph_rdunlock_main_loop(); /* if we are streaming the entire chain, the result will have no backing * file, and specifying one is therefore an error */ @@ -3021,9 +3030,12 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) } /* Early check to avoid creating target */ + bdrv_graph_rdlock_main_loop(); if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_MIRROR_SOURCE, errp)) { + bdrv_graph_rdunlock_main_loop(); return; } + bdrv_graph_rdunlock_main_loop(); aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); @@ -3409,9 +3421,12 @@ void qmp_change_backing_file(const char *device, /* even though we are not necessarily operating on bs, we need it to * determine if block ops are currently prohibited on the chain */ + bdrv_graph_rdlock_main_loop(); if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_CHANGE, errp)) { + bdrv_graph_rdunlock_main_loop(); goto out; } + bdrv_graph_rdunlock_main_loop(); /* final sanity check */ if (!bdrv_chain_contains(bs, image_bs)) { diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h index 794ef34ded..6bfafe781d 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -246,7 +246,9 @@ bdrv_attach_child(BlockDriverState *parent_bs, BdrvChildRole child_role, Error **errp); -bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp); +bool GRAPH_RDLOCK +bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp); + void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason); void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason); void bdrv_op_block_all(BlockDriverState *bs, Error *reason);