diff options
| -rw-r--r-- | block/file-posix.c | 100 | ||||
| -rw-r--r-- | qapi/block-core.json | 7 |
2 files changed, 104 insertions, 3 deletions
diff --git a/block/file-posix.c b/block/file-posix.c index 3707ea2d1c..5a602cfe37 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -161,6 +161,7 @@ typedef struct BDRVRawState { bool page_cache_inconsistent:1; bool has_fallocate; bool needs_alignment; + bool check_cache_dropped; PRManager *pr_mgr; } BDRVRawState; @@ -168,6 +169,7 @@ typedef struct BDRVRawState { typedef struct BDRVRawReopenState { int fd; int open_flags; + bool check_cache_dropped; } BDRVRawReopenState; static int fd_open(BlockDriverState *bs); @@ -415,6 +417,11 @@ static QemuOptsList raw_runtime_opts = { .type = QEMU_OPT_STRING, .help = "id of persistent reservation manager object (default: none)", }, + { + .name = "x-check-cache-dropped", + .type = QEMU_OPT_BOOL, + .help = "check that page cache was dropped on live migration (default: off)" + }, { /* end of list */ } }, }; @@ -500,6 +507,9 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, } } + s->check_cache_dropped = qemu_opt_get_bool(opts, "x-check-cache-dropped", + false); + s->open_flags = open_flags; raw_parse_flags(bdrv_flags, &s->open_flags); @@ -777,6 +787,7 @@ static int raw_reopen_prepare(BDRVReopenState *state, { BDRVRawState *s; BDRVRawReopenState *rs; + QemuOpts *opts; int ret = 0; Error *local_err = NULL; @@ -787,6 +798,19 @@ static int raw_reopen_prepare(BDRVReopenState *state, state->opaque = g_new0(BDRVRawReopenState, 1); rs = state->opaque; + rs->fd = -1; + + /* Handle options changes */ + opts = qemu_opts_create(&raw_runtime_opts, NULL, 0, &error_abort); + qemu_opts_absorb_qdict(opts, state->options, &local_err); + if (local_err) { + error_propagate(errp, local_err); + ret = -EINVAL; + goto out; + } + + rs->check_cache_dropped = qemu_opt_get_bool(opts, "x-check-cache-dropped", + s->check_cache_dropped); if (s->type == FTYPE_CD) { rs->open_flags |= O_NONBLOCK; @@ -794,8 +818,6 @@ static int raw_reopen_prepare(BDRVReopenState *state, raw_parse_flags(state->flags, &rs->open_flags); - rs->fd = -1; - int fcntl_flags = O_APPEND | O_NONBLOCK; #ifdef O_NOATIME fcntl_flags |= O_NOATIME; @@ -850,6 +872,8 @@ static int raw_reopen_prepare(BDRVReopenState *state, } } +out: + qemu_opts_del(opts); return ret; } @@ -858,6 +882,7 @@ static void raw_reopen_commit(BDRVReopenState *state) BDRVRawReopenState *rs = state->opaque; BDRVRawState *s = state->bs->opaque; + s->check_cache_dropped = rs->check_cache_dropped; s->open_flags = rs->open_flags; qemu_close(s->fd); @@ -2236,6 +2261,73 @@ static int coroutine_fn raw_co_block_status(BlockDriverState *bs, return ret | BDRV_BLOCK_OFFSET_VALID; } +#if defined(__linux__) +/* Verify that the file is not in the page cache */ +static void check_cache_dropped(BlockDriverState *bs, Error **errp) +{ + const size_t window_size = 128 * 1024 * 1024; + BDRVRawState *s = bs->opaque; + void *window = NULL; + size_t length = 0; + unsigned char *vec; + size_t page_size; + off_t offset; + off_t end; + + /* mincore(2) page status information requires 1 byte per page */ + page_size = sysconf(_SC_PAGESIZE); + vec = g_malloc(DIV_ROUND_UP(window_size, page_size)); + + end = raw_getlength(bs); + + for (offset = 0; offset < end; offset += window_size) { + void *new_window; + size_t new_length; + size_t vec_end; + size_t i; + int ret; + + /* Unmap previous window if size has changed */ + new_length = MIN(end - offset, window_size); + if (new_length != length) { + munmap(window, length); + window = NULL; + length = 0; + } + + new_window = mmap(window, new_length, PROT_NONE, MAP_PRIVATE, + s->fd, offset); + if (new_window == MAP_FAILED) { + error_setg_errno(errp, errno, "mmap failed"); + break; + } + + window = new_window; + length = new_length; + + ret = mincore(window, length, vec); + if (ret < 0) { + error_setg_errno(errp, errno, "mincore failed"); + break; + } + + vec_end = DIV_ROUND_UP(length, page_size); + for (i = 0; i < vec_end; i++) { + if (vec[i] & 0x1) { + error_setg(errp, "page cache still in use!"); + break; + } + } + } + + if (window) { + munmap(window, length); + } + + g_free(vec); +} +#endif /* __linux__ */ + static void coroutine_fn raw_co_invalidate_cache(BlockDriverState *bs, Error **errp) { @@ -2269,6 +2361,10 @@ static void coroutine_fn raw_co_invalidate_cache(BlockDriverState *bs, error_setg_errno(errp, ret, "fadvise failed"); return; } + + if (s->check_cache_dropped) { + check_cache_dropped(bs, errp); + } #else /* __linux__ */ /* Do nothing. Live migration to a remote host with cache.direct=off is * unsupported on other host operating systems. Cache consistency issues diff --git a/qapi/block-core.json b/qapi/block-core.json index c50517bff3..21c3470234 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -2530,6 +2530,10 @@ # @locking: whether to enable file locking. If set to 'auto', only enable # when Open File Descriptor (OFD) locking API is available # (default: auto, since 2.10) +# @x-check-cache-dropped: whether to check that page cache was dropped on live +# migration. May cause noticeable delays if the image +# file is large, do not use in production. +# (default: off) (since: 2.13) # # Since: 2.9 ## @@ -2537,7 +2541,8 @@ 'data': { 'filename': 'str', '*pr-manager': 'str', '*locking': 'OnOffAuto', - '*aio': 'BlockdevAioOptions' } } + '*aio': 'BlockdevAioOptions', + '*x-check-cache-dropped': 'bool' } } ## # @BlockdevOptionsNull: |