/* * QEMU System Emulator block driver * * Copyright (c) 2003 Fabrice Bellard * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "qemu/osdep.h" #include "qemu-common.h" #include "trace.h" #include "block/block_int.h" #include "block/blockjob.h" #include "qemu/error-report.h" #include "qemu/module.h" #include "qapi/qmp/qerror.h" #include "qapi/qmp/qbool.h" #include "qapi/qmp/qjson.h" #include "sysemu/block-backend.h" #include "sysemu/sysemu.h" #include "qemu/notify.h" #include "qemu/coroutine.h" #include "block/qapi.h" #include "qmp-commands.h" #include "qemu/timer.h" #include "qapi-event.h" #include "block/throttle-groups.h" #ifdef CONFIG_BSD #include #include #ifndef __DragonFly__ #include #endif #endif #ifdef _WIN32 #include #endif #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ struct BdrvStates bdrv_states = QTAILQ_HEAD_INITIALIZER(bdrv_states); static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states = QTAILQ_HEAD_INITIALIZER(graph_bdrv_states); static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states = QTAILQ_HEAD_INITIALIZER(all_bdrv_states); static QLIST_HEAD(, BlockDriver) bdrv_drivers = QLIST_HEAD_INITIALIZER(bdrv_drivers); static int bdrv_open_inherit(BlockDriverState **pbs, const char *filename, const char *reference, QDict *options, int flags, BlockDriverState *parent, const BdrvChildRole *child_role, Error **errp); /* If non-zero, use only whitelisted block drivers */ static int use_bdrv_whitelist; static void bdrv_close(BlockDriverState *bs); #ifdef _WIN32 static int is_windows_drive_prefix(const char *filename) { return (((filename[0] >= 'a' && filename[0] <= 'z') || (filename[0] >= 'A' && filename[0] <= 'Z')) && filename[1] == ':'); } int is_windows_drive(const char *filename) { if (is_windows_drive_prefix(filename) && filename[2] == '\0') return 1; if (strstart(filename, "\\\\.\\", NULL) || strstart(filename, "//./", NULL)) return 1; return 0; } #endif size_t bdrv_opt_mem_align(BlockDriverState *bs) { if (!bs || !bs->drv) { /* page size or 4k (hdd sector size) should be on the safe side */ return MAX(4096, getpagesize()); } return bs->bl.opt_mem_alignment; } size_t bdrv_min_mem_align(BlockDriverState *bs) { if (!bs || !bs->drv) { /* page size or 4k (hdd sector size) should be on the safe side */ return MAX(4096, getpagesize()); } return bs->bl.min_mem_alignment; } /* check if the path starts with ":" */ int path_has_protocol(const char *path) { const char *p; #ifdef _WIN32 if (is_windows_drive(path) || is_windows_drive_prefix(path)) { return 0; } p = path + strcspn(path, ":/\\"); #else p = path + strcspn(path, ":/"); #endif return *p == ':'; } int path_is_absolute(const char *path) { #ifdef _WIN32 /* specific case for names like: "\\.\d:" */ if (is_windows_drive(path) || is_windows_drive_prefix(path)) { return 1; } return (*path == '/' || *path == '\\'); #else return (*path == '/'); #endif } /* if filename is absolute, just copy it to dest. Otherwise, build a path to it by considering it is relative to base_path. URL are supported. */ void path_combine(char *dest, int dest_size, const char *base_path, const char *filename) { const char *p, *p1; int len; if (dest_size <= 0) return; if (path_is_absolute(filename)) { pstrcpy(dest, dest_size, filename); } else { p = strchr(base_path, ':'); if (p) p++; else p = base_path; p1 = strrchr(base_path, '/'); #ifdef _WIN32 { const char *p2; p2 = strrchr(base_path, '\\'); if (!p1 || p2 > p1) p1 = p2; } #endif if (p1) p1++; else p1 = base_path; if (p1 > p) p = p1; len = p - base_path; if (len > dest_size - 1) len = dest_size - 1; memcpy(dest, base_path, len); dest[len] = '\0'; pstrcat(dest, dest_size, filename); } } void bdrv_get_full_backing_filename_from_filename(const char *backed, const char *backing, char *dest, size_t sz, Error **errp) { if (backing[0] == '\0' || path_has_protocol(backing) || path_is_absolute(backing)) { pstrcpy(dest, sz, backing); } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) { error_setg(errp, "Cannot use relative backing file names for '%s'", backed); } else { path_combine(dest, sz, backed, backing); } } void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz, Error **errp) { char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename; bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file, dest, sz, errp); } void bdrv_register(BlockDriver *bdrv) { bdrv_setup_io_funcs(bdrv); QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list); } BlockDriverState *bdrv_new_root(void) { BlockDriverState *bs = bdrv_new(); QTAILQ_INSERT_TAIL(&bdrv_states, bs, device_list); return bs; } BlockDriverState *bdrv_new(void) { BlockDriverState *bs; int i; bs = g_new0(BlockDriverState, 1); QLIST_INIT(&bs->dirty_bitmaps); for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { QLIST_INIT(&bs->op_blockers[i]); } notifier_with_return_list_init(&bs->before_write_notifiers); qemu_co_queue_init(&bs->throttled_reqs[0]); qemu_co_queue_init(&bs->throttled_reqs[1]); bs->refcnt = 1; bs->aio_context = qemu_get_aio_context(); QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list); return bs; } BlockDriver *bdrv_find_format(const char *format_name) { BlockDriver *drv1; QLIST_FOREACH(drv1, &bdrv_drivers, list) { if (!strcmp(drv1->format_name, format_name)) { return drv1; } } return NULL; } static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only) { static const char *whitelist_rw[] = { CONFIG_BDRV_RW_WHITELIST }; static const char *whitelist_ro[] = { CONFIG_BDRV_RO_WHITELIST }; const char **p; if (!whitelist_rw[0] && !whitelist_ro[0]) { return 1; /* no whitelist, anything goes */ } for (p = whitelist_rw; *p; p++) { if (!strcmp(drv->format_name, *p)) { return 1; } } if (read_only) { for (p = whitelist_ro; *p; p++) { if (!strcmp(drv->format_name, *p)) { return 1; } } } return 0; } typedef struct CreateCo { BlockDriver *drv; char *filename; QemuOpts *opts; int ret; Error *err; } CreateCo; static void coroutine_fn bdrv_create_co_entry(void *opaque) { Error *local_err = NULL; int ret; CreateCo *cco = opaque; assert(cco->drv); ret = cco->drv->bdrv_create(cco->filename, cco->opts, &local_err); if (local_err) { error_propagate(&cco->err, local_err); } cco->ret = ret; } int bdrv_create(BlockDriver *drv, const char* filename, QemuOpts *opts, Error **errp) { int ret; Coroutine *co; CreateCo cco = { .drv = drv, .filename = g_strdup(filename), .opts = opts, .ret = NOT_DONE, .err = NULL, }; if (!drv->bdrv_create) { error_setg(errp, "Driver '%s' does not support image creation", drv->format_name); ret = -ENOTSUP; goto out; } if (qemu_in_coroutine()) { /* Fast-path if already in coroutine context */ bdrv_create_co_entry(&cco); } else { co = qemu_coroutine_create(bdrv_create_co_entry); qemu_coroutine_enter(co, &cco); while (cco.ret == NOT_DONE) { aio_poll(qemu_get_aio_context(), true); } } ret = cco.ret; if (ret < 0) { if (cco.err) { error_propagate(errp, cco.err); } else { error_setg_errno(errp, -ret, "Could not create image"); } } out: g_free(cco.filename); return ret; } int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp) { BlockDriver *drv; Error *local_err = NULL; int ret; drv = bdrv_find_protocol(filename, true, errp); if (drv == NULL) { return -ENOENT; } ret = bdrv_create(drv, filename, opts, &local_err); if (local_err) { error_propagate(errp, local_err); } return ret; } /** * Try to get @bs's logical and physical block size. * On success, store them in @bsz struct and return 0. * On failure return -errno. * @bs must not be empty. */ int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_probe_blocksizes) { return drv->bdrv_probe_blocksizes(bs, bsz); } return -ENOTSUP; } /** * Try to get @bs's geometry (cyls, heads, sectors). * On success, store them in @geo struct and return 0. * On failure return -errno. * @bs must not be empty. */ int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_probe_geometry) { return drv->bdrv_probe_geometry(bs, geo); } return -ENOTSUP; } /* * Create a uniquely-named empty temporary file. * Return 0 upon success, otherwise a negative errno value. */ int get_tmp_filename(char *filename, int size) { #ifdef _WIN32 char temp_dir[MAX_PATH]; /* GetTempFileName requires that its output buffer (4th param) have length MAX_PATH or greater. */ assert(size >= MAX_PATH); return (GetTempPath(MAX_PATH, temp_dir) && GetTempFileName(temp_dir, "qem", 0, filename) ? 0 : -GetLastError()); #else int fd; const char *tmpdir; tmpdir = getenv("TMPDIR"); if (!tmpdir) { tmpdir = "/var/tmp"; } if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) { return -EOVERFLOW; } fd = mkstemp(filename); if (fd < 0) { return -errno; } if (close(fd) != 0) { unlink(filename); return -errno; } return 0; #endif } /* * Detect host devices. By convention, /dev/cdrom[N] is always * recognized as a host CDROM. */ static BlockDriver *find_hdev_driver(const char *filename) { int score_max = 0, score; BlockDriver *drv = NULL, *d; QLIST_FOREACH(d, &bdrv_drivers, list) { if (d->bdrv_probe_device) { score = d->bdrv_probe_device(filename); if (score > score_max) { score_max = score; drv = d; } } } return drv; } BlockDriver *bdrv_find_protocol(const char *filename, bool allow_protocol_prefix, Error **errp) { BlockDriver *drv1; char protocol[128]; int len; const char *p; /* TODO Drivers without bdrv_file_open must be specified explicitly */ /* * XXX(hch): we really should not let host device detection * override an explicit protocol specification, but moving this * later breaks access to device names with colons in them. * Thanks to the brain-dead persistent naming schemes on udev- * based Linux systems those actually are quite common. */ drv1 = find_hdev_driver(filename); if (drv1) { return drv1; } if (!path_has_protocol(filename) || !allow_protocol_prefix) { return &bdrv_file; } p = strchr(filename, ':'); assert(p != NULL); len = p - filename; if (len > sizeof(protocol) - 1) len = sizeof(protocol) - 1; memcpy(protocol, filename, len); protocol[len] = '\0'; QLIST_FOREACH(drv1, &bdrv_drivers, list) { if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) { return drv1; } } error_setg(errp, "Unknown protocol '%s'", protocol); return NULL; } /* * Guess image format by probing its contents. * This is not a good idea when your image is raw (CVE-2008-2004), but * we do it anyway for backward compatibility. * * @buf contains the image's first @buf_size bytes. * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE, * but can be smaller if the image file is smaller) * @filename is its filename. * * For all block drivers, call the bdrv_probe() method to get its * probing score. * Return the first block driver with the highest probing score. */ BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, const char *filename) { int score_max = 0, score; BlockDriver *drv = NULL, *d; QLIST_FOREACH(d, &bdrv_drivers, list) { if (d->bdrv_probe) { score = d->bdrv_probe(buf, buf_size, filename); if (score > score_max) { score_max = score; drv = d; } } } return drv; } static int find_image_format(BlockDriverState *bs, const char *filename, BlockDriver **pdrv, Error **errp) { BlockDriver *drv; uint8_t buf[BLOCK_PROBE_BUF_SIZE]; int ret = 0; /* Return the raw BlockDriver * to scsi-generic devices or empty drives */ if (bdrv_is_sg(bs) || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) { *pdrv = &bdrv_raw; return ret; } ret = bdrv_pread(bs, 0, buf, sizeof(buf)); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read image for determining its " "format"); *pdrv = NULL; return ret; } drv = bdrv_probe_all(buf, ret, filename); if (!drv) { error_setg(errp, "Could not determine image format: No compatible " "driver found"); ret = -ENOENT; } *pdrv = drv; return ret; } /** * Set the current 'total_sectors' value * Return 0 on success, -errno on error. */ static int refresh_total_sectors(BlockDriverState *bs, int64_t hint) { BlockDriver *drv = bs->drv; /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */ if (bdrv_is_sg(bs)) return 0; /* query actual device if possible, otherwise just trust the hint */ if (drv->bdrv_getlength) { int64_t length = drv->bdrv_getlength(bs); if (length < 0) { return length; } hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE); } bs->total_sectors = hint; return 0; } /** * Combines a QDict of new block driver @options with any missing options taken * from @old_options, so that leaving out an option defaults to its old value. */ static void bdrv_join_options(BlockDriverState *bs, QDict *options, QDict *old_options) { if (bs->drv && bs->drv->bdrv_join_options) { bs->drv->bdrv_join_options(options, old_options); } else { qdict_join(options, old_options, false); } } /** * Set open flags for a given discard mode * * Return 0 on success, -1 if the discard mode was invalid. */ int bdrv_parse_discard_flags(const char *mode, int *flags) { *flags &= ~BDRV_O_UNMAP; if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) { /* do nothing */ } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) { *flags |= BDRV_O_UNMAP; } else { return -1; } return 0; } /** * Set open flags for a given cache mode * * Return 0 on success, -1 if the cache mode was invalid. */ int bdrv_parse_cache_flags(const char *mode, int *flags) { *flags &= ~BDRV_O_CACHE_MASK; if (!strcmp(mode, "off") || !strcmp(mode, "none")) { *flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; } else if (!strcmp(mode, "directsync")) { *flags |= BDRV_O_NOCACHE; } else if (!strcmp(mode, "writeback")) { *flags |= BDRV_O_CACHE_WB; } else if (!strcmp(mode, "unsafe")) { *flags |= BDRV_O_CACHE_WB; *flags |= BDRV_O_NO_FLUSH; } else if (!strcmp(mode, "writethrough")) { /* this is the default */ } else { return -1; } return 0; } /* * Returns the options and flags that a temporary snapshot should get, based on * the originally requested flags (the originally requested image will have * flags like a backing file) */ static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options, int parent_flags, QDict *parent_options) { *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY; /* For temporary files, unconditional cache=unsafe is fine */ qdict_set_default_str(child_options, BDRV_OPT_CACHE_WB, "on"); qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off"); qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on"); } /* * Returns the options and flags that bs->file should get if a protocol driver * is expected, based on the given options and flags for the parent BDS */ static void bdrv_inherited_options(int *child_flags, QDict *child_options, int parent_flags, QDict *parent_options) { int flags = parent_flags; /* Enable protocol handling, disable format probing for bs->file */ flags |= BDRV_O_PROTOCOL; /* If the cache mode isn't explicitly set, inherit direct and no-flush from * the parent. */ qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT); qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH); /* Our block drivers take care to send flushes and respect unmap policy, * so we can default to enable both on lower layers regardless of the * corresponding parent options. */ qdict_set_default_str(child_options, BDRV_OPT_CACHE_WB, "on"); flags |= BDRV_O_UNMAP; /* Clear flags that only apply to the top layer */ flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ); *child_flags = flags; } const BdrvChildRole child_file = { .inherit_options = bdrv_inherited_options, }; /* * Returns the options and flags that bs->file should get if the use of formats * (and not only protocols) is permitted for it, based on the given options and * flags for the parent BDS */ static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options, int parent_flags, QDict *parent_options) { child_file.inherit_options(child_flags, child_options, parent_flags, parent_options); *child_flags &= ~BDRV_O_PROTOCOL; } const BdrvChildRole child_format = { .inherit_options = bdrv_inherited_fmt_options, }; /* * Returns the options and flags that bs->backing should get, based on the * given options and flags for the parent BDS */ static void bdrv_backing_options(int *child_flags, QDict *child_options, int parent_flags, QDict *parent_options) { int flags = parent_flags; /* The cache mode is inherited unmodified for backing files */ qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_WB); qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT); qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH); /* backing files always opened read-only */ flags &= ~(BDRV_O_RDWR | BDRV_O_COPY_ON_READ); /* snapshot=on is handled on the top layer */ flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY); *child_flags = flags; } static const BdrvChildRole child_backing = { .inherit_options = bdrv_backing_options, }; static int bdrv_open_flags(BlockDriverState *bs, int flags) { int open_flags = flags | BDRV_O_CACHE_WB; /* * Clear flags that are internal to the block layer before opening the * image. */ open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL); /* * Snapshots should be writable. */ if (flags & BDRV_O_TEMPORARY) { open_flags |= BDRV_O_RDWR; } return open_flags; } static void update_flags_from_options(int *flags, QemuOpts *opts) { *flags &= ~BDRV_O_CACHE_MASK; assert(qemu_opt_find(opts, BDRV_OPT_CACHE_WB)); if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_WB, false)) { *flags |= BDRV_O_CACHE_WB; } assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH)); if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) { *flags |= BDRV_O_NO_FLUSH; } assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT)); if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) { *flags |= BDRV_O_NOCACHE; } } static void update_options_from_flags(QDict *options, int flags) { if (!qdict_haskey(options, BDRV_OPT_CACHE_WB)) { qdict_put(options, BDRV_OPT_CACHE_WB, qbool_from_bool(flags & BDRV_O_CACHE_WB)); } if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) { qdict_put(options, BDRV_OPT_CACHE_DIRECT, qbool_from_bool(flags & BDRV_O_NOCACHE)); } if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) { qdict_put(options, BDRV_OPT_CACHE_NO_FLUSH, qbool_from_bool(flags & BDRV_O_NO_FLUSH)); } } static void bdrv_assign_node_name(BlockDriverState *bs, const char *node_name, Error **errp) { char *gen_node_name = NULL; if (!node_name) { node_name = gen_node_name = id_generate(ID_BLOCK); } else if (!id_wellformed(node_name)) { /* * Check for empty string or invalid characters, but not if it is * generated (generated names use characters not available to the user) */ error_setg(errp, "Invalid node name"); return; } /* takes care of avoiding namespaces collisions */ if (blk_by_name(node_name)) { error_setg(errp, "node-name=%s is conflicting with a device id", node_name); goto out; } /* takes care of avoiding duplicates node names */ if (bdrv_find_node(node_name)) { error_setg(errp, "Duplicate node name"); goto out; } /* copy node name into the bs and insert it into the graph list */ pstrcpy(bs->node_name, sizeof(bs->node_name), node_name); QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list); out: g_free(gen_node_name); } static QemuOptsList bdrv_runtime_opts = { .name = "bdrv_common", .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head), .desc = { { .name = "node-name", .type = QEMU_OPT_STRING, .help = "Node name of the block device node", }, { .name = "driver", .type = QEMU_OPT_STRING, .help = "Block driver to use for the node", }, { .name = BDRV_OPT_CACHE_WB, .type = QEMU_OPT_BOOL, .help = "Enable writeback mode", }, { .name = BDRV_OPT_CACHE_DIRECT, .type = QEMU_OPT_BOOL, .help = "Bypass software writeback cache on the host", }, { .name = BDRV_OPT_CACHE_NO_FLUSH, .type = QEMU_OPT_BOOL, .help = "Ignore flush requests", }, { /* end of list */ } }, }; /* * Common part for opening disk images and files * * Removes all processed options from *options. */ static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file, QDict *options, Error **errp) { int ret, open_flags; const char *filename; const char *driver_name = NULL; const char *node_name = NULL; QemuOpts *opts; BlockDriver *drv; Error *local_err = NULL; assert(bs->file == NULL); assert(options != NULL && bs->options != options); opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort); qemu_opts_absorb_qdict(opts, options, &local_err); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto fail_opts; } driver_name = qemu_opt_get(opts, "driver"); drv = bdrv_find_format(driver_name); assert(drv != NULL); if (file != NULL) { filename = file->bs->filename; } else { filename = qdict_get_try_str(options, "filename"); } if (drv->bdrv_needs_filename && !filename) { error_setg(errp, "The '%s' block driver requires a file name", drv->format_name); ret = -EINVAL; goto fail_opts; } trace_bdrv_open_common(bs, filename ?: "", bs->open_flags, drv->format_name); node_name = qemu_opt_get(opts, "node-name"); bdrv_assign_node_name(bs, node_name, &local_err); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto fail_opts; } bs->request_alignment = 512; bs->zero_beyond_eof = true; bs->read_only = !(bs->open_flags & BDRV_O_RDWR); if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) { error_setg(errp, !bs->read_only && bdrv_is_whitelisted(drv, true) ? "Driver '%s' can only be used for read-only devices" : "Driver '%s' is not whitelisted", drv->format_name); ret = -ENOTSUP; goto fail_opts; } assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */ if (bs->open_flags & BDRV_O_COPY_ON_READ) { if (!bs->read_only) { bdrv_enable_copy_on_read(bs); } else { error_setg(errp, "Can't use copy-on-read on read-only device"); ret = -EINVAL; goto fail_opts; } } if (filename != NULL) { pstrcpy(bs->filename, sizeof(bs->filename), filename); } else { bs->filename[0] = '\0'; } pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename); bs->drv = drv; bs->opaque = g_malloc0(drv->instance_size); /* Apply cache mode options */ update_flags_from_options(&bs->open_flags, opts); bdrv_set_enable_write_cache(bs, bs->open_flags & BDRV_O_CACHE_WB); /* Open the image, either directly or using a protocol */ open_flags = bdrv_open_flags(bs, bs->open_flags); if (drv->bdrv_file_open) { assert(file == NULL); assert(!drv->bdrv_needs_filename || filename != NULL); ret = drv->bdrv_file_open(bs, options, open_flags, &local_err); } else { if (file == NULL) { error_setg(errp, "Can't use '%s' as a block driver for the " "protocol level", drv->format_name); ret = -EINVAL; goto free_and_fail; } bs->file = file; ret = drv->bdrv_open(bs, options, open_flags, &local_err); } if (ret < 0) { if (local_err) { error_propagate(errp, local_err); } else if (bs->filename[0]) { error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename); } else { error_setg_errno(errp, -ret, "Could not open image"); } goto free_and_fail; } if (bs->encrypted) { error_report("Encrypted images are deprecated"); error_printf("Support for them will be removed in a future release.\n" "You can use 'qemu-img convert' to convert your image" " to an unencrypted one.\n"); } ret = refresh_total_sectors(bs, bs->total_sectors); if (ret < 0) { error_setg_errno(errp, -ret, "Could not refresh total sector count"); goto free_and_fail; } bdrv_refresh_limits(bs, &local_err); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto free_and_fail; } assert(bdrv_opt_mem_align(bs) != 0); assert(bdrv_min_mem_align(bs) != 0); assert((bs->request_alignment != 0) || bdrv_is_sg(bs)); qemu_opts_del(opts); return 0; free_and_fail: bs->file = NULL; g_free(bs->opaque); bs->opaque = NULL; bs->drv = NULL; fail_opts: qemu_opts_del(opts); return ret; } static QDict *parse_json_filename(const char *filename, Error **errp) { QObject *options_obj; QDict *options; int ret; ret = strstart(filename, "json:", &filename); assert(ret); options_obj = qobject_from_json(filename); if (!options_obj) { error_setg(errp, "Could not parse the JSON options"); return NULL; } if (qobject_type(options_obj) != QTYPE_QDICT) { qobject_decref(options_obj); error_setg(errp, "Invalid JSON object given"); return NULL; } options = qobject_to_qdict(options_obj); qdict_flatten(options); return options; } static void parse_json_protocol(QDict *options, const char **pfilename, Error **errp) { QDict *json_options; Error *local_err = NULL; /* Parse json: pseudo-protocol */ if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) { return; } json_options = parse_json_filename(*pfilename, &local_err); if (local_err) { error_propagate(errp, local_err); return; } /* Options given in the filename have lower priority than options * specified directly */ qdict_join(options, json_options, false); QDECREF(json_options); *pfilename = NULL; } /* * Fills in default options for opening images and converts the legacy * filename/flags pair to option QDict entries. * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a * block driver has been specified explicitly. */ static int bdrv_fill_options(QDict **options, const char *filename, int *flags, Error **errp) { const char *drvname; bool protocol = *flags & BDRV_O_PROTOCOL; bool parse_filename = false; BlockDriver *drv = NULL; Error *local_err = NULL; drvname = qdict_get_try_str(*options, "driver"); if (drvname) { drv = bdrv_find_format(drvname); if (!drv) { error_setg(errp, "Unknown driver '%s'", drvname); return -ENOENT; } /* If the user has explicitly specified the driver, this choice should * override the BDRV_O_PROTOCOL flag */ protocol = drv->bdrv_file_open; } if (protocol) { *flags |= BDRV_O_PROTOCOL; } else { *flags &= ~BDRV_O_PROTOCOL; } /* Translate cache options from flags into options */ update_options_from_flags(*options, *flags); /* Fetch the file name from the options QDict if necessary */ if (protocol && filename) { if (!qdict_haskey(*options, "filename")) { qdict_put(*options, "filename", qstring_from_str(filename)); parse_filename = true; } else { error_setg(errp, "Can't specify 'file' and 'filename' options at " "the same time"); return -EINVAL; } } /* Find the right block driver */ filename = qdict_get_try_str(*options, "filename"); if (!drvname && protocol) { if (filename) { drv = bdrv_find_protocol(filename, parse_filename, errp); if (!drv) { return -EINVAL; } drvname = drv->format_name; qdict_put(*options, "driver", qstring_from_str(drvname)); } else { error_setg(errp, "Must specify either driver or file"); return -EINVAL; } } assert(drv || !protocol); /* Driver-specific filename parsing */ if (drv && drv->bdrv_parse_filename && parse_filename) { drv->bdrv_parse_filename(filename, *options, &local_err); if (local_err) { error_propagate(errp, local_err); return -EINVAL; } if (!drv->bdrv_needs_filename) { qdict_del(*options, "filename"); } } return 0; } static BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, BlockDriverState *child_bs, const char *child_name, const BdrvChildRole *child_role) { BdrvChild *child = g_new(BdrvChild, 1); *child = (BdrvChild) { .bs = child_bs, .name = g_strdup(child_name), .role = child_role, }; QLIST_INSERT_HEAD(&parent_bs->children, child, next); QLIST_INSERT_HEAD(&child_bs->parents, child, next_parent); return child; } static void bdrv_detach_child(BdrvChild *child) { QLIST_REMOVE(child, next); QLIST_REMOVE(child, next_parent); g_free(child->name); g_free(child); } void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) { BlockDriverState *child_bs; if (child == NULL) { return; } if (child->bs->inherits_from == parent) { child->bs->inherits_from = NULL; } child_bs = child->bs; bdrv_detach_child(child); bdrv_unref(child_bs); } /* * Sets the backing file link of a BDS. A new reference is created; callers * which don't need their own reference any more must call bdrv_unref(). */ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd) { if (backing_hd) { bdrv_ref(backing_hd); } if (bs->backing) { assert(bs->backing_blocker); bdrv_op_unblock_all(bs->backing->bs, bs->backing_blocker); bdrv_unref_child(bs, bs->backing); } else if (backing_hd) { error_setg(&bs->backing_blocker, "node is used as backing hd of '%s'", bdrv_get_device_or_node_name(bs)); } if (!backing_hd) { error_free(bs->backing_blocker); bs->backing_blocker = NULL; bs->backing = NULL; goto out; } bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing); bs->open_flags &= ~BDRV_O_NO_BACKING; pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename); pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_hd->drv ? backing_hd->drv->format_name : ""); bdrv_op_block_all(backing_hd, bs->backing_blocker); /* Otherwise we won't be able to commit due to check in bdrv_commit */ bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET, bs->backing_blocker); out: bdrv_refresh_limits(bs, NULL); } /* * Opens the backing file for a BlockDriverState if not yet open * * bdref_key specifies the key for the image's BlockdevRef in the options QDict. * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict * itself, all options starting with "${bdref_key}." are considered part of the * BlockdevRef. * * TODO Can this be unified with bdrv_open_image()? */ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, const char *bdref_key, Error **errp) { char *backing_filename = g_malloc0(PATH_MAX); char *bdref_key_dot; const char *reference = NULL; int ret = 0; BlockDriverState *backing_hd; QDict *options; QDict *tmp_parent_options = NULL; Error *local_err = NULL; if (bs->backing != NULL) { goto free_exit; } /* NULL means an empty set of options */ if (parent_options == NULL) { tmp_parent_options = qdict_new(); parent_options = tmp_parent_options; } bs->open_flags &= ~BDRV_O_NO_BACKING; bdref_key_dot = g_strdup_printf("%s.", bdref_key); qdict_extract_subqdict(parent_options, &options, bdref_key_dot); g_free(bdref_key_dot); reference = qdict_get_try_str(parent_options, bdref_key); if (reference || qdict_haskey(options, "file.filename")) { backing_filename[0] = '\0'; } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { QDECREF(options); goto free_exit; } else { bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX, &local_err); if (local_err) { ret = -EINVAL; error_propagate(errp, local_err); QDECREF(options); goto free_exit; } } if (!bs->drv || !bs->drv->supports_backing) { ret = -EINVAL; error_setg(errp, "Driver doesn't support backing files"); QDECREF(options); goto free_exit; } if (bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) { qdict_put(options, "driver", qstring_from_str(bs->backing_format)); } backing_hd = NULL; ret = bdrv_open_inherit(&backing_hd, *backing_filename ? backing_filename : NULL, reference, options, 0, bs, &child_backing, errp); if (ret < 0) { bs->open_flags |= BDRV_O_NO_BACKING; error_prepend(errp, "Could not open backing file: "); goto free_exit; } /* Hook up the backing file link; drop our reference, bs owns the * backing_hd reference now */ bdrv_set_backing_hd(bs, backing_hd); bdrv_unref(backing_hd); qdict_del(parent_options, bdref_key); free_exit: g_free(backing_filename); QDECREF(tmp_parent_options); return ret; } /* * Opens a disk image whose options are given as BlockdevRef in another block * device's options. * * If allow_none is true, no image will be opened if filename is false and no * BlockdevRef is given. NULL will be returned, but errp remains unset. * * bdrev_key specifies the key for the image's BlockdevRef in the options QDict. * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict * itself, all options starting with "${bdref_key}." are considered part of the * BlockdevRef. * * The BlockdevRef will be removed from the options QDict. */ BdrvChild *bdrv_open_child(const char *filename, QDict *options, const char *bdref_key, BlockDriverState* parent, const BdrvChildRole *child_role, bool allow_none, Error **errp) { BdrvChild *c = NULL; BlockDriverState *bs; QDict *image_options; int ret; char *bdref_key_dot; const char *reference; assert(child_role != NULL); bdref_key_dot = g_strdup_printf("%s.", bdref_key); qdict_extract_subqdict(options, &image_options, bdref_key_dot); g_free(bdref_key_dot); reference = qdict_get_try_str(options, bdref_key); if (!filename && !reference && !qdict_size(image_options)) { if (!allow_none) { error_setg(errp, "A block device must be specified for \"%s\"", bdref_key); } QDECREF(image_options); goto done; } bs = NULL; ret = bdrv_open_inherit(&bs, filename, reference, image_options, 0, parent, child_role, errp); if (ret < 0) { goto done; } c = bdrv_attach_child(parent, bs, bdref_key, child_role); done: qdict_del(options, bdref_key); return c; } static int bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, QDict *snapshot_options, Error **errp) { /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */ char *tmp_filename = g_malloc0(PATH_MAX + 1); int64_t total_size; QemuOpts *opts = NULL; BlockDriverState *bs_snapshot; Error *local_err = NULL; int ret; /* if snapshot, we create a temporary backing file and open it instead of opening 'filename' directly */ /* Get the required size from the image */ total_size = bdrv_getlength(bs); if (total_size < 0) { ret = total_size; error_setg_errno(errp, -total_size, "Could not get image size"); goto out; } /* Create the temporary image */ ret = get_tmp_filename(tmp_filename, PATH_MAX + 1); if (ret < 0) { error_setg_errno(errp, -ret, "Could not get temporary filename"); goto out; } opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0, &error_abort); qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort); ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp); qemu_opts_del(opts); if (ret < 0) { error_prepend(errp, "Could not create temporary overlay '%s': ", tmp_filename); goto out; } /* Prepare options QDict for the temporary file */ qdict_put(snapshot_options, "file.driver", qstring_from_str("file")); qdict_put(snapshot_options, "file.filename", qstring_from_str(tmp_filename)); qdict_put(snapshot_options, "driver", qstring_from_str("qcow2")); bs_snapshot = bdrv_new(); ret = bdrv_open(&bs_snapshot, NULL, NULL, snapshot_options, flags, &local_err); snapshot_options = NULL; if (ret < 0) { error_propagate(errp, local_err); goto out; } bdrv_append(bs_snapshot, bs); out: QDECREF(snapshot_options); g_free(tmp_filename); return ret; } /* * Opens a disk image (raw, qcow2, vmdk, ...) * * options is a QDict of options to pass to the block drivers, or NULL for an * empty set of options. The reference to the QDict belongs to the block layer * after the call (even on failure), so if the caller intends to reuse the * dictionary, it needs to use QINCREF() before calling bdrv_open. * * If *pbs is NULL, a new BDS will be created with a pointer to it stored there. * If it is not NULL, the referenced BDS will be reused. * * The reference parameter may be used to specify an existing block device which * should be opened. If specified, neither options nor a filename may be given, * nor can an existing BDS be reused (that is, *pbs has to be NULL). */ static int bdrv_open_inherit(BlockDriverState **pbs, const char *filename, const char *reference, QDict *options, int flags, BlockDriverState *parent, const BdrvChildRole *child_role, Error **errp) { int ret; BdrvChild *file = NULL; BlockDriverState *bs; BlockDriver *drv = NULL; const char *drvname; const char *backing; Error *local_err = NULL; QDict *snapshot_options = NULL; int snapshot_flags = 0; assert(pbs); assert(!child_role || !flags); assert(!child_role == !parent); if (reference) { bool options_non_empty = options ? qdict_size(options) : false; QDECREF(options); if (*pbs) { error_setg(errp, "Cannot reuse an existing BDS when referencing " "another block device"); return -EINVAL; } if (filename || options_non_empty) { error_setg(errp, "Cannot reference an existing block device with " "additional options or a new filename"); return -EINVAL; } bs = bdrv_lookup_bs(reference, reference, errp); if (!bs) { return -ENODEV; } bdrv_ref(bs); *pbs = bs; return 0; } if (*pbs) { bs = *pbs; } else { bs = bdrv_new(); } /* NULL means an empty set of options */ if (options == NULL) { options = qdict_new(); } /* json: syntax counts as explicit options, as if in the QDict */ parse_json_protocol(options, &filename, &local_err); if (local_err) { ret = -EINVAL; goto fail; } bs->explicit_options = qdict_clone_shallow(options); if (child_role) { bs->inherits_from = parent; child_role->inherit_options(&flags, options, parent->open_flags, parent->options); } ret = bdrv_fill_options(&options, filename, &flags, &local_err); if (local_err) { goto fail; } bs->open_flags = flags; bs->options = options; options = qdict_clone_shallow(options); /* Find the right image format driver */ drvname = qdict_get_try_str(options, "driver"); if (drvname) { drv = bdrv_find_format(drvname); if (!drv) { error_setg(errp, "Unknown driver: '%s'", drvname); ret = -EINVAL; goto fail; } } assert(drvname || !(flags & BDRV_O_PROTOCOL)); backing = qdict_get_try_str(options, "backing"); if (backing && *backing == '\0') { flags |= BDRV_O_NO_BACKING; qdict_del(options, "backing"); } /* Open image file without format layer */ if ((flags & BDRV_O_PROTOCOL) == 0) { if (flags & BDRV_O_RDWR) { flags |= BDRV_O_ALLOW_RDWR; } if (flags & BDRV_O_SNAPSHOT) { snapshot_options = qdict_new(); bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options, flags, options); bdrv_backing_options(&flags, options, flags, options); } bs->open_flags = flags; file = bdrv_open_child(filename, options, "file", bs, &child_file, true, &local_err); if (local_err) { ret = -EINVAL; goto fail; } } /* Image format probing */ bs->probed = !drv; if (!drv && file) { ret = find_image_format(file->bs, filename, &drv, &local_err); if (ret < 0) { goto fail; } /* * This option update would logically belong in bdrv_fill_options(), * but we first need to open bs->file for the probing to work, while * opening bs->file already requires the (mostly) final set of options * so that cache mode etc. can be inherited. * * Adding the driver later is somewhat ugly, but it's not an option * that would ever be inherited, so it's correct. We just need to make * sure to update both bs->options (which has the full effective * options for bs) and options (which has file.* already removed). */ qdict_put(bs->options, "driver", qstring_from_str(drv->format_name)); qdict_put(options, "driver", qstring_from_str(drv->format_name)); } else if (!drv) { error_setg(errp, "Must specify either driver or file"); ret = -EINVAL; goto fail; } /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */ assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open); /* file must be NULL if a protocol BDS is about to be created * (the inverse results in an error message from bdrv_open_common()) */ assert(!(flags & BDRV_O_PROTOCOL) || !file); /* Open the image */ ret = bdrv_open_common(bs, file, options, &local_err); if (ret < 0) { goto fail; } if (file && (bs->file != file)) { bdrv_unref_child(bs, file); file = NULL; } /* If there is a backing file, use it */ if ((flags & BDRV_O_NO_BACKING) == 0) { ret = bdrv_open_backing_file(bs, options, "backing", &local_err); if (ret < 0) { goto close_and_fail; } } bdrv_refresh_filename(bs); /* Check if any unknown options were used */ if (options && (qdict_size(options) != 0)) { const QDictEntry *entry = qdict_first(options); if (flags & BDRV_O_PROTOCOL) { error_setg(errp, "Block protocol '%s' doesn't support the option " "'%s'", drv->format_name, entry->key); } else { error_setg(errp, "Block format '%s' does not support the option '%s'", drv->format_name, entry->key); } ret = -EINVAL; goto close_and_fail; } if (!bdrv_key_required(bs)) { if (bs->blk) { blk_dev_change_media_cb(bs->blk, true); } } else if (!runstate_check(RUN_STATE_PRELAUNCH) && !runstate_check(RUN_STATE_INMIGRATE) && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */ error_setg(errp, "Guest must be stopped for opening of encrypted image"); ret = -EBUSY; goto close_and_fail; } QDECREF(options); *pbs = bs; /* For snapshot=on, create a temporary qcow2 overlay. bs points to the * temporary snapshot afterwards. */ if (snapshot_flags) { ret = bdrv_append_temp_snapshot(bs, snapshot_flags, snapshot_options, &local_err); snapshot_options = NULL; if (local_err) { goto close_and_fail; } } return 0; fail: if (file != NULL) { bdrv_unref_child(bs, file); } QDECREF(snapshot_options); QDECREF(bs->explicit_options); QDECREF(bs->options); QDECREF(options); bs->options = NULL; if (!*pbs) { /* If *pbs is NULL, a new BDS has been created in this function and needs to be freed now. Otherwise, it does not need to be closed, since it has not really been opened yet. */ bdrv_unref(bs); } if (local_err) { error_propagate(errp, local_err); } return ret; close_and_fail: /* See fail path, but now the BDS has to be always closed */ if (*pbs) { bdrv_close(bs); } else { bdrv_unref(bs); } QDECREF(snapshot_options); QDECREF(options); if (local_err) { error_propagate(errp, local_err); } return ret; } int bdrv_open(BlockDriverState **pbs, const char *filename, const char *reference, QDict *options, int flags, Error **errp) { return bdrv_open_inherit(pbs, filename, reference, options, flags, NULL, NULL, errp); } typedef struct BlockReopenQueueEntry { bool prepared; BDRVReopenState state; QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; } BlockReopenQueueEntry; /* * Adds a BlockDriverState to a simple queue for an atomic, transactional * reopen of multiple devices. * * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT * already performed, or alternatively may be NULL a new BlockReopenQueue will * be created and initialized. This newly created BlockReopenQueue should be * passed back in for subsequent calls that are intended to be of the same * atomic 'set'. * * bs is the BlockDriverState to add to the reopen queue. * * options contains the changed options for the associated bs * (the BlockReopenQueue takes ownership) * * flags contains the open flags for the associated bs * * returns a pointer to bs_queue, which is either the newly allocated * bs_queue, or the existing bs_queue being used. * */ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, BlockDriverState *bs, QDict *options, int flags, const BdrvChildRole *role, QDict *parent_options, int parent_flags) { assert(bs != NULL); BlockReopenQueueEntry *bs_entry; BdrvChild *child; QDict *old_options, *explicit_options; if (bs_queue == NULL) { bs_queue = g_new0(BlockReopenQueue, 1); QSIMPLEQ_INIT(bs_queue); } if (!options) { options = qdict_new(); } /* * Precedence of options: * 1. Explicitly passed in options (highest) * 2. Set in flags (only for top level) * 3. Retained from explicitly set options of bs * 4. Inherited from parent node * 5. Retained from effective options of bs */ if (!parent_options) { /* * Any setting represented by flags is always updated. If the * corresponding QDict option is set, it takes precedence. Otherwise * the flag is translated into a QDict option. The old setting of bs is * not considered. */ update_options_from_flags(options, flags); } /* Old explicitly set values (don't overwrite by inherited value) */ old_options = qdict_clone_shallow(bs->explicit_options); bdrv_join_options(bs, options, old_options); QDECREF(old_options); explicit_options = qdict_clone_shallow(options); /* Inherit from parent node */ if (parent_options) { assert(!flags); role->inherit_options(&flags, options, parent_flags, parent_options); } /* Old values are used for options that aren't set yet */ old_options = qdict_clone_shallow(bs->options); bdrv_join_options(bs, options, old_options); QDECREF(old_options); /* bdrv_open() masks this flag out */ flags &= ~BDRV_O_PROTOCOL; QLIST_FOREACH(child, &bs->children, next) { QDict *new_child_options; char *child_key_dot; /* reopen can only change the options of block devices that were * implicitly created and inherited options. For other (referenced) * block devices, a syntax like "backing.foo" results in an error. */ if (child->bs->inherits_from != bs) { continue; } child_key_dot = g_strdup_printf("%s.", child->name); qdict_extract_subqdict(options, &new_child_options, child_key_dot); g_free(child_key_dot); bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0, child->role, options, flags); } bs_entry = g_new0(BlockReopenQueueEntry, 1); QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry); bs_entry->state.bs = bs; bs_entry->state.options = options; bs_entry->state.explicit_options = explicit_options; bs_entry->state.flags = flags; return bs_queue; } BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, BlockDriverState *bs, QDict *options, int flags) { return bdrv_reopen_queue_child(bs_queue, bs, options, flags, NULL, NULL, 0); } /* * Reopen multiple BlockDriverStates atomically & transactionally. * * The queue passed in (bs_queue) must have been built up previous * via bdrv_reopen_queue(). * * Reopens all BDS specified in the queue, with the appropriate * flags. All devices are prepared for reopen, and failure of any * device will cause all device changes to be abandonded, and intermediate * data cleaned up. * * If all devices prepare successfully, then the changes are committed * to all devices. * */ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) { int ret = -1; BlockReopenQueueEntry *bs_entry, *next; Error *local_err = NULL; assert(bs_queue != NULL); bdrv_drain_all(); QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) { error_propagate(errp, local_err); goto cleanup; } bs_entry->prepared = true; } /* If we reach this point, we have success and just need to apply the * changes */ QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { bdrv_reopen_commit(&bs_entry->state); } ret = 0; cleanup: QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { if (ret && bs_entry->prepared) { bdrv_reopen_abort(&bs_entry->state); } else if (ret) { QDECREF(bs_entry->state.explicit_options); } QDECREF(bs_entry->state.options); g_free(bs_entry); } g_free(bs_queue); return ret; } /* Reopen a single BlockDriverState with the specified flags. */ int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp) { int ret = -1; Error *local_err = NULL; BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags); ret = bdrv_reopen_multiple(queue, &local_err); if (local_err != NULL) { error_propagate(errp, local_err); } return ret; } /* * Prepares a BlockDriverState for reopen. All changes are staged in the * 'opaque' field of the BDRVReopenState, which is used and allocated by * the block driver layer .bdrv_reopen_prepare() * * bs is the BlockDriverState to reopen * flags are the new open flags * queue is the reopen queue * * Returns 0 on success, non-zero on error. On error errp will be set * as well. * * On failure, bdrv_reopen_abort() will be called to clean up any data. * It is the responsibility of the caller to then call the abort() or * commit() for any other BDS that have been left in a prepare() state * */ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, Error **errp) { int ret = -1; Error *local_err = NULL; BlockDriver *drv; QemuOpts *opts; const char *value; assert(reopen_state != NULL); assert(reopen_state->bs->drv != NULL); drv = reopen_state->bs->drv; /* Process generic block layer options */ opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort); qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto error; } update_flags_from_options(&reopen_state->flags, opts); /* If a guest device is attached, it owns WCE */ if (reopen_state->bs->blk && blk_get_attached_dev(reopen_state->bs->blk)) { bool old_wce = bdrv_enable_write_cache(reopen_state->bs); bool new_wce = (reopen_state->flags & BDRV_O_CACHE_WB); if (old_wce != new_wce) { error_setg(errp, "Cannot change cache.writeback: Device attached"); ret = -EINVAL; goto error; } } /* node-name and driver must be unchanged. Put them back into the QDict, so * that they are checked at the end of this function. */ value = qemu_opt_get(opts, "node-name"); if (value) { qdict_put(reopen_state->options, "node-name", qstring_from_str(value)); } value = qemu_opt_get(opts, "driver"); if (value) { qdict_put(reopen_state->options, "driver", qstring_from_str(value)); } /* if we are to stay read-only, do not allow permission change * to r/w */ if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) && reopen_state->flags & BDRV_O_RDWR) { error_setg(errp, "Node '%s' is read only", bdrv_get_device_or_node_name(reopen_state->bs)); goto error; } ret = bdrv_flush(reopen_state->bs); if (ret) { error_setg_errno(errp, -ret, "Error flushing drive"); goto error; } if (drv->bdrv_reopen_prepare) { ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err); if (ret) { if (local_err != NULL) { error_propagate(errp, local_err); } else { error_setg(errp, "failed while preparing to reopen image '%s'", reopen_state->bs->filename); } goto error; } } else { /* It is currently mandatory to have a bdrv_reopen_prepare() * handler for each supported drv. */ error_setg(errp, "Block format '%s' used by node '%s' " "does not support reopening files", drv->format_name, bdrv_get_device_or_node_name(reopen_state->bs)); ret = -1; goto error; } /* Options that are not handled are only okay if they are unchanged * compared to the old state. It is expected that some options are only * used for the initial open, but not reopen (e.g. filename) */ if (qdict_size(reopen_state->options)) { const QDictEntry *entry = qdict_first(reopen_state->options); do { QString *new_obj = qobject_to_qstring(entry->value); const char *new = qstring_get_str(new_obj); const char *old = qdict_get_try_str(reopen_state->bs->options, entry->key); if (!old || strcmp(new, old)) { error_setg(errp, "Cannot change the option '%s'", entry->key); ret = -EINVAL; goto error; } } while ((entry = qdict_next(reopen_state->options, entry))); } ret = 0; error: qemu_opts_del(opts); return ret; } /* * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and * makes them final by swapping the staging BlockDriverState contents into * the active BlockDriverState contents. */ void bdrv_reopen_commit(BDRVReopenState *reopen_state) { BlockDriver *drv; assert(reopen_state != NULL); drv = reopen_state->bs->drv; assert(drv != NULL); /* If there are any driver level actions to take */ if (drv->bdrv_reopen_commit) { drv->bdrv_reopen_commit(reopen_state); } /* set BDS specific flags now */ QDECREF(reopen_state->bs->explicit_options); reopen_state->bs->explicit_options = reopen_state->explicit_options; reopen_state->bs->open_flags = reopen_state->flags; reopen_state->bs->enable_write_cache = !!(reopen_state->flags & BDRV_O_CACHE_WB); reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR); bdrv_refresh_limits(reopen_state->bs, NULL); } /* * Abort the reopen, and delete and free the staged changes in * reopen_state */ void bdrv_reopen_abort(BDRVReopenState *reopen_state) { BlockDriver *drv; assert(reopen_state != NULL); drv = reopen_state->bs->drv; assert(drv != NULL); if (drv->bdrv_reopen_abort) { drv->bdrv_reopen_abort(reopen_state); } QDECREF(reopen_state->explicit_options); } static void bdrv_close(BlockDriverState *bs) { BdrvAioNotifier *ban, *ban_next; assert(!bs->job); /* Disable I/O limits and drain all pending throttled requests */ if (bs->throttle_state) { bdrv_io_limits_disable(bs); } bdrv_drained_begin(bs); /* complete I/O */ bdrv_flush(bs); bdrv_drain(bs); /* in case flush left pending I/O */ bdrv_release_named_dirty_bitmaps(bs); assert(QLIST_EMPTY(&bs->dirty_bitmaps)); if (bs->blk) { blk_dev_change_media_cb(bs->blk, false); } if (bs->drv) { BdrvChild *child, *next; bs->drv->bdrv_close(bs); bs->drv = NULL; bdrv_set_backing_hd(bs, NULL); if (bs->file != NULL) { bdrv_unref_child(bs, bs->file); bs->file = NULL; } QLIST_FOREACH_SAFE(child, &bs->children, next, next) { /* TODO Remove bdrv_unref() from drivers' close function and use * bdrv_unref_child() here */ if (child->bs->inherits_from == bs) { child->bs->inherits_from = NULL; } bdrv_detach_child(child); } g_free(bs->opaque); bs->opaque = NULL; bs->copy_on_read = 0; bs->backing_file[0] = '\0'; bs->backing_format[0] = '\0'; bs->total_sectors = 0; bs->encrypted = 0; bs->valid_key = 0; bs->sg = 0; bs->zero_beyond_eof = false; QDECREF(bs->options); QDECREF(bs->explicit_options); bs->options = NULL; QDECREF(bs->full_open_options); bs->full_open_options = NULL; } QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) { g_free(ban); } QLIST_INIT(&bs->aio_notifiers); bdrv_drained_end(bs); } void bdrv_close_all(void) { BlockDriverState *bs; AioContext *aio_context; /* Drop references from requests still in flight, such as canceled block * jobs whose AIO context has not been polled yet */ bdrv_drain_all(); blk_remove_all_bs(); blockdev_close_all_bdrv_states(); /* Cancel all block jobs */ while (!QTAILQ_EMPTY(&all_bdrv_states)) { QTAILQ_FOREACH(bs, &all_bdrv_states, bs_list) { aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); if (bs->job) { block_job_cancel_sync(bs->job); aio_context_release(aio_context); break; } aio_context_release(aio_context); } /* All the remaining BlockDriverStates are referenced directly or * indirectly from block jobs, so there needs to be at least one BDS * directly used by a block job */ assert(bs); } } /* Note that bs->device_list.tqe_prev is initially null, * and gets set to non-null by QTAILQ_INSERT_TAIL(). Establish * the useful invariant "bs in bdrv_states iff bs->tqe_prev" by * resetting it to null on remove. */ void bdrv_device_remove(BlockDriverState *bs) { QTAILQ_REMOVE(&bdrv_states, bs, device_list); bs->device_list.tqe_prev = NULL; } /* make a BlockDriverState anonymous by removing from bdrv_state and * graph_bdrv_state list. Also, NULL terminate the device_name to prevent double remove */ void bdrv_make_anon(BlockDriverState *bs) { /* Take care to remove bs from bdrv_states only when it's actually * in it. */ if (bs->device_list.tqe_prev) { bdrv_device_remove(bs); } if (bs->node_name[0] != '\0') { QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list); } bs->node_name[0] = '\0'; } /* Fields that need to stay with the top-level BDS */ static void bdrv_move_feature_fields(BlockDriverState *bs_dest, BlockDriverState *bs_src) { /* move some fields that need to stay attached to the device */ /* dev info */ bs_dest->copy_on_read = bs_src->copy_on_read; bs_dest->enable_write_cache = bs_src->enable_write_cache; /* dirty bitmap */ bs_dest->dirty_bitmaps = bs_src->dirty_bitmaps; } static void change_parent_backing_link(BlockDriverState *from, BlockDriverState *to) { BdrvChild *c, *next; QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) { assert(c->role != &child_backing); c->bs = to; QLIST_REMOVE(c, next_parent); QLIST_INSERT_HEAD(&to->parents, c, next_parent); bdrv_ref(to); bdrv_unref(from); } if (from->blk) { blk_set_bs(from->blk, to); if (!to->device_list.tqe_prev) { QTAILQ_INSERT_BEFORE(from, to, device_list); } bdrv_device_remove(from); } } static void swap_feature_fields(BlockDriverState *bs_top, BlockDriverState *bs_new) { BlockDriverState tmp; bdrv_move_feature_fields(&tmp, bs_top); bdrv_move_feature_fields(bs_top, bs_new); bdrv_move_feature_fields(bs_new, &tmp); assert(!bs_new->throttle_state); if (bs_top->throttle_state) { assert(bs_top->io_limits_enabled); bdrv_io_limits_enable(bs_new, throttle_group_get_name(bs_top)); bdrv_io_limits_disable(bs_top); } } /* * Add new bs contents at the top of an image chain while the chain is * live, while keeping required fields on the top layer. * * This will modify the BlockDriverState fields, and swap contents * between bs_new and bs_top. Both bs_new and bs_top are modified. * * bs_new must not be attached to a BlockBackend. * * This function does not create any image files. * * bdrv_append() takes ownership of a bs_new reference and unrefs it because * that's what the callers commonly need. bs_new will be referenced by the old * parents of bs_top after bdrv_append() returns. If the caller needs to keep a * reference of its own, it must call bdrv_ref(). */ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top) { assert(!bdrv_requests_pending(bs_top)); assert(!bdrv_requests_pending(bs_new)); bdrv_ref(bs_top); change_parent_backing_link(bs_top, bs_new); /* Some fields always stay on top of the backing file chain */ swap_feature_fields(bs_top, bs_new); bdrv_set_backing_hd(bs_new, bs_top); bdrv_unref(bs_top); /* bs_new is now referenced by its new parents, we don't need the * additional reference any more. */ bdrv_unref(bs_new); } void bdrv_replace_in_backing_chain(BlockDriverState *old, BlockDriverState *new) { assert(!bdrv_requests_pending(old)); assert(!bdrv_requests_pending(new)); bdrv_ref(old); if (old->blk) { /* As long as these fields aren't in BlockBackend, but in the top-level * BlockDriverState, it's not possible for a BDS to have two BBs. * * We really want to copy the fields from old to new, but we go for a * swap instead so that pointers aren't duplicated and cause trouble. * (Also, bdrv_swap() used to do the same.) */ assert(!new->blk); swap_feature_fields(old, new); } change_parent_backing_link(old, new); /* Change backing files if a previously independent node is added to the * chain. For active commit, we replace top by its own (indirect) backing * file and don't do anything here so we don't build a loop. */ if (new->backing == NULL && !bdrv_chain_contains(backing_bs(old), new)) { bdrv_set_backing_hd(new, backing_bs(old)); bdrv_set_backing_hd(old, NULL); } bdrv_unref(old); } static void bdrv_delete(BlockDriverState *bs) { assert(!bs->job); assert(bdrv_op_blocker_is_empty(bs)); assert(!bs->refcnt); bdrv_close(bs); /* remove from list, if necessary */ bdrv_make_anon(bs); QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list); g_free(bs); } /* * Run consistency checks on an image * * Returns 0 if the check could be completed (it doesn't mean that the image is * free of errors) or -errno when an internal error occurred. The results of the * check are stored in res. */ int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix) { if (bs->drv == NULL) { return -ENOMEDIUM; } if (bs->drv->bdrv_check == NULL) { return -ENOTSUP; } memset(res, 0, sizeof(*res)); return bs->drv->bdrv_check(bs, res, fix); } #define COMMIT_BUF_SECTORS 2048 /* commit COW file into the raw image */ int bdrv_commit(BlockDriverState *bs) { BlockDriver *drv = bs->drv; int64_t sector, total_sectors, length, backing_length; int n, ro, open_flags; int ret = 0; uint8_t *buf = NULL; if (!drv) return -ENOMEDIUM; if (!bs->backing) { return -ENOTSUP; } if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) || bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) { return -EBUSY; } ro = bs->backing->bs->read_only; open_flags = bs->backing->bs->open_flags; if (ro) { if (bdrv_reopen(bs->backing->bs, open_flags | BDRV_O_RDWR, NULL)) { return -EACCES; } } length = bdrv_getlength(bs); if (length < 0) { ret = length; goto ro_cleanup; } backing_length = bdrv_getlength(bs->backing->bs); if (backing_length < 0) { ret = backing_length; goto ro_cleanup; } /* If our top snapshot is larger than the backing file image, * grow the backing file image if possible. If not possible, * we must return an error */ if (length > backing_length) { ret = bdrv_truncate(bs->backing->bs, length); if (ret < 0) { goto ro_cleanup; } } total_sectors = length >> BDRV_SECTOR_BITS; /* qemu_try_blockalign() for bs will choose an alignment that works for * bs->backing->bs as well, so no need to compare the alignment manually. */ buf = qemu_try_blockalign(bs, COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE); if (buf == NULL) { ret = -ENOMEM; goto ro_cleanup; } for (sector = 0; sector < total_sectors; sector += n) { ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n); if (ret < 0) { goto ro_cleanup; } if (ret) { ret = bdrv_read(bs, sector, buf, n); if (ret < 0) { goto ro_cleanup; } ret = bdrv_write(bs->backing->bs, sector, buf, n); if (ret < 0) { goto ro_cleanup; } } } if (drv->bdrv_make_empty) { ret = drv->bdrv_make_empty(bs); if (ret < 0) { goto ro_cleanup; } bdrv_flush(bs); } /* * Make sure all data we wrote to the backing device is actually * stable on disk. */ if (bs->backing) { bdrv_flush(bs->backing->bs); } ret = 0; ro_cleanup: qemu_vfree(buf); if (ro) { /* ignoring error return here */ bdrv_reopen(bs->backing->bs, open_flags & ~BDRV_O_RDWR, NULL); } return ret; } /* * Return values: * 0 - success * -EINVAL - backing format specified, but no file * -ENOSPC - can't update the backing file because no space is left in the * image file header * -ENOTSUP - format driver doesn't support changing the backing file */ int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file, const char *backing_fmt) { BlockDriver *drv = bs->drv; int ret; /* Backing file format doesn't make sense without a backing file */ if (backing_fmt && !backing_file) { return -EINVAL; } if (drv->bdrv_change_backing_file != NULL) { ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt); } else { ret = -ENOTSUP; } if (ret == 0) { pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); } return ret; } /* * Finds the image layer in the chain that has 'bs' as its backing file. * * active is the current topmost image. * * Returns NULL if bs is not found in active's image chain, * or if active == bs. * * Returns the bottommost base image if bs == NULL. */ BlockDriverState *bdrv_find_overlay(BlockDriverState *active, BlockDriverState *bs) { while (active && bs != backing_bs(active)) { active = backing_bs(active); } return active; } /* Given a BDS, searches for the base layer. */ BlockDriverState *bdrv_find_base(BlockDriverState *bs) { return bdrv_find_overlay(bs, NULL); } /* * Drops images above 'base' up to and including 'top', and sets the image * above 'top' to have base as its backing file. * * Requires that the overlay to 'top' is opened r/w, so that the backing file * information in 'bs' can be properly updated. * * E.g., this will convert the following chain: * bottom <- base <- intermediate <- top <- active * * to * * bottom <- base <- active * * It is allowed for bottom==base, in which case it converts: * * base <- intermediate <- top <- active * * to * * base <- active * * If backing_file_str is non-NULL, it will be used when modifying top's * overlay image metadata. * * Error conditions: * if active == top, that is considered an error * */ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, BlockDriverState *base, const char *backing_file_str) { BlockDriverState *new_top_bs = NULL; int ret = -EIO; if (!top->drv || !base->drv) { goto exit; } new_top_bs = bdrv_find_overlay(active, top); if (new_top_bs == NULL) { /* we could not find the image above 'top', this is an error */ goto exit; } /* special case of new_top_bs->backing->bs already pointing to base - nothing * to do, no intermediate images */ if (backing_bs(new_top_bs) == base) { ret = 0; goto exit; } /* Make sure that base is in the backing chain of top */ if (!bdrv_chain_contains(top, base)) { goto exit; } /* success - we can delete the intermediate states, and link top->base */ backing_file_str = backing_file_str ? backing_file_str : base->filename; ret = bdrv_change_backing_file(new_top_bs, backing_file_str, base->drv ? base->drv->format_name : ""); if (ret) { goto exit; } bdrv_set_backing_hd(new_top_bs, base); ret = 0; exit: return ret; } /** * Truncate file to 'offset' bytes (needed only for file protocols) */ int bdrv_truncate(BlockDriverState *bs, int64_t offset) { BlockDriver *drv = bs->drv; int ret; if (!drv) return -ENOMEDIUM; if (!drv->bdrv_truncate) return -ENOTSUP; if (bs->read_only) return -EACCES; ret = drv->bdrv_truncate(bs, offset); if (ret == 0) { ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); bdrv_dirty_bitmap_truncate(bs); if (bs->blk) { blk_dev_resize_cb(bs->blk); } } return ret; } /** * Length of a allocated file in bytes. Sparse files are counted by actual * allocated space. Return < 0 if error or unknown. */ int64_t bdrv_get_allocated_file_size(BlockDriverState *bs) { BlockDriver *drv = bs->drv; if (!drv) { return -ENOMEDIUM; } if (drv->bdrv_get_allocated_file_size) { return drv->bdrv_get_allocated_file_size(bs); } if (bs->file) { return bdrv_get_allocated_file_size(bs->file->bs); } return -ENOTSUP; } /** * Return number of sectors on success, -errno on error. */ int64_t bdrv_nb_sectors(BlockDriverState *bs) { BlockDriver *drv = bs->drv; if (!drv) return -ENOMEDIUM; if (drv->has_variable_length) { int ret = refresh_total_sectors(bs, bs->total_sectors); if (ret < 0) { return ret; } } return bs->total_sectors; } /** * Return length in bytes on success, -errno on error. * The length is always a multiple of BDRV_SECTOR_SIZE. */ int64_t bdrv_getlength(BlockDriverState *bs) { int64_t ret = bdrv_nb_sectors(bs); ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret; return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE; } /* return 0 as number of sectors if no device present or error */ void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr) { int64_t nb_sectors = bdrv_nb_sectors(bs); *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors; } int bdrv_is_read_only(BlockDriverState *bs) { return bs->read_only; } int bdrv_is_sg(BlockDriverState *bs) { return bs->sg; } int bdrv_enable_write_cache(BlockDriverState *bs) { return bs->enable_write_cache; } void bdrv_set_enable_write_cache(BlockDriverState *bs, bool wce) { bs->enable_write_cache = wce; /* so a reopen() will preserve wce */ if (wce) { bs->open_flags |= BDRV_O_CACHE_WB; } else { bs->open_flags &= ~BDRV_O_CACHE_WB; } } int bdrv_is_encrypted(BlockDriverState *bs) { if (bs->backing && bs->backing->bs->encrypted) { return 1; } return bs->encrypted; } int bdrv_key_required(BlockDriverState *bs) { BdrvChild *backing = bs->backing; if (backing && backing->bs->encrypted && !backing->bs->valid_key) { return 1; } return (bs->encrypted && !bs->valid_key); } int bdrv_set_key(BlockDriverState *bs, const char *key) { int ret; if (bs->backing && bs->backing->bs->encrypted) { ret = bdrv_set_key(bs->backing->bs, key); if (ret < 0) return ret; if (!bs->encrypted) return 0; } if (!bs->encrypted) { return -EINVAL; } else if (!bs->drv || !bs->drv->bdrv_set_key) { return -ENOMEDIUM; } ret = bs->drv->bdrv_set_key(bs, key); if (ret < 0) { bs->valid_key = 0; } else if (!bs->valid_key) { bs->valid_key = 1; if (bs->blk) { /* call the change callback now, we skipped it on open */ blk_dev_change_media_cb(bs->blk, true); } } return ret; } /* * Provide an encryption key for @bs. * If @key is non-null: * If @bs is not encrypted, fail. * Else if the key is invalid, fail. * Else set @bs's key to @key, replacing the existing key, if any. * If @key is null: * If @bs is encrypted and still lacks a key, fail. * Else do nothing. * On failure, store an error object through @errp if non-null. */ void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp) { if (key) { if (!bdrv_is_encrypted(bs)) { error_setg(errp, "Node '%s' is not encrypted", bdrv_get_device_or_node_name(bs)); } else if (bdrv_set_key(bs, key) < 0) { error_setg(errp, QERR_INVALID_PASSWORD); } } else { if (bdrv_key_required(bs)) { error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED, "'%s' (%s) is encrypted", bdrv_get_device_or_node_name(bs), bdrv_get_encrypted_filename(bs)); } } } const char *bdrv_get_format_name(BlockDriverState *bs) { return bs->drv ? bs->drv->format_name : NULL; } static int qsort_strcmp(const void *a, const void *b) { return strcmp(a, b); } void bdrv_iterate_format(void (*it)(void *opaque, const char *name), void *opaque) { BlockDriver *drv; int count = 0; int i; const char **formats = NULL; QLIST_FOREACH(drv, &bdrv_drivers, list) { if (drv->format_name) { bool found = false; int i = count; while (formats && i && !found) { found = !strcmp(formats[--i], drv->format_name); } if (!found) { formats = g_renew(const char *, formats, count + 1); formats[count++] = drv->format_name; } } } qsort(formats, count, sizeof(formats[0]), qsort_strcmp); for (i = 0; i < count; i++) { it(opaque, formats[i]); } g_free(formats); } /* This function is to find a node in the bs graph */ BlockDriverState *bdrv_find_node(const char *node_name) { BlockDriverState *bs; assert(node_name); QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { if (!strcmp(node_name, bs->node_name)) { return bs; } } return NULL; } /* Put this QMP function here so it can access the static graph_bdrv_states. */ BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp) { BlockDeviceInfoList *list, *entry; BlockDriverState *bs; list = NULL; QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { BlockDeviceInfo *info = bdrv_block_device_info(bs, errp); if (!info) { qapi_free_BlockDeviceInfoList(list); return NULL; } entry = g_malloc0(sizeof(*entry)); entry->value = info; entry->next = list; list = entry; } return list; } BlockDriverState *bdrv_lookup_bs(const char *device, const char *node_name, Error **errp) { BlockBackend *blk; BlockDriverState *bs; if (device) { blk = blk_by_name(device); if (blk) { bs = blk_bs(blk); if (!bs) { error_setg(errp, "Device '%s' has no medium", device); } return bs; } } if (node_name) { bs = bdrv_find_node(node_name); if (bs) { return bs; } } error_setg(errp, "Cannot find device=%s nor node_name=%s", device ? device : "", node_name ? node_name : ""); return NULL; } /* If 'base' is in the same chain as 'top', return true. Otherwise, * return false. If either argument is NULL, return false. */ bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base) { while (top && top != base) { top = backing_bs(top); } return top != NULL; } BlockDriverState *bdrv_next_node(BlockDriverState *bs) { if (!bs) { return QTAILQ_FIRST(&graph_bdrv_states); } return QTAILQ_NEXT(bs, node_list); } /* Iterates over all top-level BlockDriverStates, i.e. BDSs that are owned by * the monitor or attached to a BlockBackend */ BlockDriverState *bdrv_next(BlockDriverState *bs) { if (!bs || bs->blk) { bs = blk_next_root_bs(bs); if (bs) { return bs; } } /* Ignore all BDSs that are attached to a BlockBackend here; they have been * handled by the above block already */ do { bs = bdrv_next_monitor_owned(bs); } while (bs && bs->blk); return bs; } const char *bdrv_get_node_name(const BlockDriverState *bs) { return bs->node_name; } /* TODO check what callers really want: bs->node_name or blk_name() */ const char *bdrv_get_device_name(const BlockDriverState *bs) { return bs->blk ? blk_name(bs->blk) : ""; } /* This can be used to identify nodes that might not have a device * name associated. Since node and device names live in the same * namespace, the result is unambiguous. The exception is if both are * absent, then this returns an empty (non-null) string. */ const char *bdrv_get_device_or_node_name(const BlockDriverState *bs) { return bs->blk ? blk_name(bs->blk) : bs->node_name; } int bdrv_get_flags(BlockDriverState *bs) { return bs->open_flags; } int bdrv_has_zero_init_1(BlockDriverState *bs) { return 1; } int bdrv_has_zero_init(BlockDriverState *bs) { assert(bs->drv); /* If BS is a copy on write image, it is initialized to the contents of the base image, which may not be zeroes. */ if (bs->backing) { return 0; } if (bs->drv->bdrv_has_zero_init) { return bs->drv->bdrv_has_zero_init(bs); } /* safe default */ return 0; } bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs) { BlockDriverInfo bdi; if (bs->backing) { return false; } if (bdrv_get_info(bs, &bdi) == 0) { return bdi.unallocated_blocks_are_zero; } return false; } bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) { BlockDriverInfo bdi; if (bs->backing || !(bs->open_flags & BDRV_O_UNMAP)) { return false; } if (bdrv_get_info(bs, &bdi) == 0) { return bdi.can_write_zeroes_with_unmap; } return false; } const char *bdrv_get_encrypted_filename(BlockDriverState *bs) { if (bs->backing && bs->backing->bs->encrypted) return bs->backing_file; else if (bs->encrypted) return bs->filename; else return NULL; } void bdrv_get_backing_filename(BlockDriverState *bs, char *filename, int filename_size) { pstrcpy(filename, filename_size, bs->backing_file); } int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BlockDriver *drv = bs->drv; if (!drv) return -ENOMEDIUM; if (!drv->bdrv_get_info) return -ENOTSUP; memset(bdi, 0, sizeof(*bdi)); return drv->bdrv_get_info(bs, bdi); } ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_get_specific_info) { return drv->bdrv_get_specific_info(bs); } return NULL; } void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event) { if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) { return; } bs->drv->bdrv_debug_event(bs, event); } int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event, const char *tag) { while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) { bs = bs->file ? bs->file->bs : NULL; } if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) { return bs->drv->bdrv_debug_breakpoint(bs, event, tag); } return -ENOTSUP; } int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag) { while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) { bs = bs->file ? bs->file->bs : NULL; } if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) { return bs->drv->bdrv_debug_remove_breakpoint(bs, tag); } return -ENOTSUP; } int bdrv_debug_resume(BlockDriverState *bs, const char *tag) { while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) { bs = bs->file ? bs->file->bs : NULL; } if (bs && bs->drv && bs->drv->bdrv_debug_resume) { return bs->drv->bdrv_debug_resume(bs, tag); } return -ENOTSUP; } bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag) { while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) { bs = bs->file ? bs->file->bs : NULL; } if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) { return bs->drv->bdrv_debug_is_suspended(bs, tag); } return false; } int bdrv_is_snapshot(BlockDriverState *bs) { return !!(bs->open_flags & BDRV_O_SNAPSHOT); } /* backing_file can either be relative, or absolute, or a protocol. If it is * relative, it must be relative to the chain. So, passing in bs->filename * from a BDS as backing_file should not be done, as that may be relative to * the CWD rather than the chain. */ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, const char *backing_file) { char *filename_full = NULL; char *backing_file_full = NULL; char *filename_tmp = NULL; int is_protocol = 0; BlockDriverState *curr_bs = NULL; BlockDriverState *retval = NULL; if (!bs || !bs->drv || !backing_file) { return NULL; } filename_full = g_malloc(PATH_MAX); backing_file_full = g_malloc(PATH_MAX); filename_tmp = g_malloc(PATH_MAX); is_protocol = path_has_protocol(backing_file); for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) { /* If either of the filename paths is actually a protocol, then * compare unmodified paths; otherwise make paths relative */ if (is_protocol || path_has_protocol(curr_bs->backing_file)) { if (strcmp(backing_file, curr_bs->backing_file) == 0) { retval = curr_bs->backing->bs; break; } } else { /* If not an absolute filename path, make it relative to the current * image's filename path */ path_combine(filename_tmp, PATH_MAX, curr_bs->filename, backing_file); /* We are going to compare absolute pathnames */ if (!realpath(filename_tmp, filename_full)) { continue; } /* We need to make sure the backing filename we are comparing against * is relative to the current image filename (or absolute) */ path_combine(filename_tmp, PATH_MAX, curr_bs->filename, curr_bs->backing_file); if (!realpath(filename_tmp, backing_file_full)) { continue; } if (strcmp(backing_file_full, filename_full) == 0) { retval = curr_bs->backing->bs; break; } } } g_free(filename_full); g_free(backing_file_full); g_free(filename_tmp); return retval; } int bdrv_get_backing_file_depth(BlockDriverState *bs) { if (!bs->drv) { return 0; } if (!bs->backing) { return 0; } return 1 + bdrv_get_backing_file_depth(bs->backing->bs); } void bdrv_init(void) { module_call_init(MODULE_INIT_BLOCK); } void bdrv_init_with_whitelist(void) { use_bdrv_whitelist = 1; bdrv_init(); } void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) { Error *local_err = NULL; int ret; if (!bs->drv) { return; } if (!(bs->open_flags & BDRV_O_INACTIVE)) { return; } bs->open_flags &= ~BDRV_O_INACTIVE; if (bs->drv->bdrv_invalidate_cache) { bs->drv->bdrv_invalidate_cache(bs, &local_err); } else if (bs->file) { bdrv_invalidate_cache(bs->file->bs, &local_err); } if (local_err) { bs->open_flags |= BDRV_O_INACTIVE; error_propagate(errp, local_err); return; } ret = refresh_total_sectors(bs, bs->total_sectors); if (ret < 0) { bs->open_flags |= BDRV_O_INACTIVE; error_setg_errno(errp, -ret, "Could not refresh total sector count"); return; } } void bdrv_invalidate_cache_all(Error **errp) { BlockDriverState *bs; Error *local_err = NULL; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); bdrv_invalidate_cache(bs, &local_err); aio_context_release(aio_context); if (local_err) { error_propagate(errp, local_err); return; } } } static int bdrv_inactivate(BlockDriverState *bs) { int ret; if (bs->drv->bdrv_inactivate) { ret = bs->drv->bdrv_inactivate(bs); if (ret < 0) { return ret; } } bs->open_flags |= BDRV_O_INACTIVE; return 0; } int bdrv_inactivate_all(void) { BlockDriverState *bs; int ret; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); ret = bdrv_inactivate(bs); aio_context_release(aio_context); if (ret < 0) { return ret; } } return 0; } /**************************************************************/ /* removable device support */ /** * Return TRUE if the media is present */ bool bdrv_is_inserted(BlockDriverState *bs) { BlockDriver *drv = bs->drv; BdrvChild *child; if (!drv) { return false; } if (drv->bdrv_is_inserted) { return drv->bdrv_is_inserted(bs); } QLIST_FOREACH(child, &bs->children, next) { if (!bdrv_is_inserted(child->bs)) { return false; } } return true; } /** * Return whether the media changed since the last call to this * function, or -ENOTSUP if we don't know. Most drivers don't know. */ int bdrv_media_changed(BlockDriverState *bs) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_media_changed) { return drv->bdrv_media_changed(bs); } return -ENOTSUP; } /** * If eject_flag is TRUE, eject the media. Otherwise, close the tray */ void bdrv_eject(BlockDriverState *bs, bool eject_flag) { BlockDriver *drv = bs->drv; const char *device_name; if (drv && drv->bdrv_eject) { drv->bdrv_eject(bs, eject_flag); } device_name = bdrv_get_device_name(bs); if (device_name[0] != '\0') { qapi_event_send_device_tray_moved(device_name, eject_flag, &error_abort); } } /** * Lock or unlock the media (if it is locked, the user won't be able * to eject it manually). */ void bdrv_lock_medium(BlockDriverState *bs, bool locked) { BlockDriver *drv = bs->drv; trace_bdrv_lock_medium(bs, locked); if (drv && drv->bdrv_lock_medium) { drv->bdrv_lock_medium(bs, locked); } } /* Get a reference to bs */ void bdrv_ref(BlockDriverState *bs) { bs->refcnt++; } /* Release a previously grabbed reference to bs. * If after releasing, reference count is zero, the BlockDriverState is * deleted. */ void bdrv_unref(BlockDriverState *bs) { if (!bs) { return; } assert(bs->refcnt > 0); if (--bs->refcnt == 0) { bdrv_delete(bs); } } struct BdrvOpBlocker { Error *reason; QLIST_ENTRY(BdrvOpBlocker) list; }; bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp) { BdrvOpBlocker *blocker; assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); if (!QLIST_EMPTY(&bs->op_blockers[op])) { blocker = QLIST_FIRST(&bs->op_blockers[op]); if (errp) { *errp = error_copy(blocker->reason); error_prepend(errp, "Node '%s' is busy: ", bdrv_get_device_or_node_name(bs)); } return true; } return false; } void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason) { BdrvOpBlocker *blocker; assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); blocker = g_new0(BdrvOpBlocker, 1); blocker->reason = reason; QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list); } void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason) { BdrvOpBlocker *blocker, *next; assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) { if (blocker->reason == reason) { QLIST_REMOVE(blocker, list); g_free(blocker); } } } void bdrv_op_block_all(BlockDriverState *bs, Error *reason) { int i; for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { bdrv_op_block(bs, i, reason); } } void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason) { int i; for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { bdrv_op_unblock(bs, i, reason); } } bool bdrv_op_blocker_is_empty(BlockDriverState *bs) { int i; for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { if (!QLIST_EMPTY(&bs->op_blockers[i])) { return false; } } return true; } void bdrv_img_create(const char *filename, const char *fmt, const char *base_filename, const char *base_fmt, char *options, uint64_t img_size, int flags, Error **errp, bool quiet) { QemuOptsList *create_opts = NULL; QemuOpts *opts = NULL; const char *backing_fmt, *backing_file; int64_t size; BlockDriver *drv, *proto_drv; Error *local_err = NULL; int ret = 0; /* Find driver and parse its options */ drv = bdrv_find_format(fmt); if (!drv) { error_setg(errp, "Unknown file format '%s'", fmt); return; } proto_drv = bdrv_find_protocol(filename, true, errp); if (!proto_drv) { return; } if (!drv->create_opts) { error_setg(errp, "Format driver '%s' does not support image creation", drv->format_name); return; } if (!proto_drv->create_opts) { error_setg(errp, "Protocol driver '%s' does not support image creation", proto_drv->format_name); return; } create_opts = qemu_opts_append(create_opts, drv->create_opts); create_opts = qemu_opts_append(create_opts, proto_drv->create_opts); /* Create parameter list with default values */ opts = qemu_opts_create(create_opts, NULL, 0, &error_abort); qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort); /* Parse -o options */ if (options) { qemu_opts_do_parse(opts, options, NULL, &local_err); if (local_err) { error_report_err(local_err); local_err = NULL; error_setg(errp, "Invalid options for file format '%s'", fmt); goto out; } } if (base_filename) { qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err); if (local_err) { error_setg(errp, "Backing file not supported for file format '%s'", fmt); goto out; } } if (base_fmt) { qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err); if (local_err) { error_setg(errp, "Backing file format not supported for file " "format '%s'", fmt); goto out; } } backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); if (backing_file) { if (!strcmp(filename, backing_file)) { error_setg(errp, "Error: Trying to create an image with the " "same filename as the backing file"); goto out; } } backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); // The size for the image must always be specified, with one exception: // If we are using a backing file, we can obtain the size from there size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); if (size == -1) { if (backing_file) { BlockDriverState *bs; char *full_backing = g_new0(char, PATH_MAX); int64_t size; int back_flags; QDict *backing_options = NULL; bdrv_get_full_backing_filename_from_filename(filename, backing_file, full_backing, PATH_MAX, &local_err); if (local_err) { g_free(full_backing); goto out; } /* backing files always opened read-only */ back_flags = flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); if (backing_fmt) { backing_options = qdict_new(); qdict_put(backing_options, "driver", qstring_from_str(backing_fmt)); } bs = NULL; ret = bdrv_open(&bs, full_backing, NULL, backing_options, back_flags, &local_err); g_free(full_backing); if (ret < 0) { goto out; } size = bdrv_getlength(bs); if (size < 0) { error_setg_errno(errp, -size, "Could not get size of '%s'", backing_file); bdrv_unref(bs); goto out; } qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort); bdrv_unref(bs); } else { error_setg(errp, "Image creation needs a size parameter"); goto out; } } if (!quiet) { printf("Formatting '%s', fmt=%s ", filename, fmt); qemu_opts_print(opts, " "); puts(""); } ret = bdrv_create(drv, filename, opts, &local_err); if (ret == -EFBIG) { /* This is generally a better message than whatever the driver would * deliver (especially because of the cluster_size_hint), since that * is most probably not much different from "image too large". */ const char *cluster_size_hint = ""; if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) { cluster_size_hint = " (try using a larger cluster size)"; } error_setg(errp, "The image size is too large for file format '%s'" "%s", fmt, cluster_size_hint); error_free(local_err); local_err = NULL; } out: qemu_opts_del(opts); qemu_opts_free(create_opts); if (local_err) { error_propagate(errp, local_err); } } AioContext *bdrv_get_aio_context(BlockDriverState *bs) { return bs->aio_context; } void bdrv_detach_aio_context(BlockDriverState *bs) { BdrvAioNotifier *baf; if (!bs->drv) { return; } QLIST_FOREACH(baf, &bs->aio_notifiers, list) { baf->detach_aio_context(baf->opaque); } if (bs->throttle_state) { throttle_timers_detach_aio_context(&bs->throttle_timers); } if (bs->drv->bdrv_detach_aio_context) { bs->drv->bdrv_detach_aio_context(bs); } if (bs->file) { bdrv_detach_aio_context(bs->file->bs); } if (bs->backing) { bdrv_detach_aio_context(bs->backing->bs); } bs->aio_context = NULL; } void bdrv_attach_aio_context(BlockDriverState *bs, AioContext *new_context) { BdrvAioNotifier *ban; if (!bs->drv) { return; } bs->aio_context = new_context; if (bs->backing) { bdrv_attach_aio_context(bs->backing->bs, new_context); } if (bs->file) { bdrv_attach_aio_context(bs->file->bs, new_context); } if (bs->drv->bdrv_attach_aio_context) { bs->drv->bdrv_attach_aio_context(bs, new_context); } if (bs->throttle_state) { throttle_timers_attach_aio_context(&bs->throttle_timers, new_context); } QLIST_FOREACH(ban, &bs->aio_notifiers, list) { ban->attached_aio_context(new_context, ban->opaque); } } void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) { bdrv_drain(bs); /* ensure there are no in-flight requests */ bdrv_detach_aio_context(bs); /* This function executes in the old AioContext so acquire the new one in * case it runs in a different thread. */ aio_context_acquire(new_context); bdrv_attach_aio_context(bs, new_context); aio_context_release(new_context); } void bdrv_add_aio_context_notifier(BlockDriverState *bs, void (*attached_aio_context)(AioContext *new_context, void *opaque), void (*detach_aio_context)(void *opaque), void *opaque) { BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1); *ban = (BdrvAioNotifier){ .attached_aio_context = attached_aio_context, .detach_aio_context = detach_aio_context, .opaque = opaque }; QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list); } void bdrv_remove_aio_context_notifier(BlockDriverState *bs, void (*attached_aio_context)(AioContext *, void *), void (*detach_aio_context)(void *), void *opaque) { BdrvAioNotifier *ban, *ban_next; QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) { if (ban->attached_aio_context == attached_aio_context && ban->detach_aio_context == detach_aio_context && ban->opaque == opaque) { QLIST_REMOVE(ban, list); g_free(ban); return; } } abort(); } int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts, BlockDriverAmendStatusCB *status_cb, void *cb_opaque) { if (!bs->drv->bdrv_amend_options) { return -ENOTSUP; } return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque); } /* This function will be called by the bdrv_recurse_is_first_non_filter method * of block filter and by bdrv_is_first_non_filter. * It is used to test if the given bs is the candidate or recurse more in the * node graph. */ bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs, BlockDriverState *candidate) { /* return false if basic checks fails */ if (!bs || !bs->drv) { return false; } /* the code reached a non block filter driver -> check if the bs is * the same as the candidate. It's the recursion termination condition. */ if (!bs->drv->is_filter) { return bs == candidate; } /* Down this path the driver is a block filter driver */ /* If the block filter recursion method is defined use it to recurse down * the node graph. */ if (bs->drv->bdrv_recurse_is_first_non_filter) { return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate); } /* the driver is a block filter but don't allow to recurse -> return false */ return false; } /* This function checks if the candidate is the first non filter bs down it's * bs chain. Since we don't have pointers to parents it explore all bs chains * from the top. Some filters can choose not to pass down the recursion. */ bool bdrv_is_first_non_filter(BlockDriverState *candidate) { BlockDriverState *bs; /* walk down the bs forest recursively */ QTAILQ_FOREACH(bs, &bdrv_states, device_list) { bool perm; /* try to recurse in this top level bs */ perm = bdrv_recurse_is_first_non_filter(bs, candidate); /* candidate is the first non filter */ if (perm) { return true; } } return false; } BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs, const char *node_name, Error **errp) { BlockDriverState *to_replace_bs = bdrv_find_node(node_name); AioContext *aio_context; if (!to_replace_bs) { error_setg(errp, "Node name '%s' not found", node_name); return NULL; } aio_context = bdrv_get_aio_context(to_replace_bs); aio_context_acquire(aio_context); if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) { to_replace_bs = NULL; goto out; } /* We don't want arbitrary node of the BDS chain to be replaced only the top * most non filter in order to prevent data corruption. * Another benefit is that this tests exclude backing files which are * blocked by the backing blockers. */ if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) { error_setg(errp, "Only top most non filter can be replaced"); to_replace_bs = NULL; goto out; } out: aio_context_release(aio_context); return to_replace_bs; } static bool append_open_options(QDict *d, BlockDriverState *bs) { const QDictEntry *entry; QemuOptDesc *desc; BdrvChild *child; bool found_any = false; const char *p; for (entry = qdict_first(bs->options); entry; entry = qdict_next(bs->options, entry)) { /* Exclude options for children */ QLIST_FOREACH(child, &bs->children, next) { if (strstart(qdict_entry_key(entry), child->name, &p) && (!*p || *p == '.')) { break; } } if (child) { continue; } /* And exclude all non-driver-specific options */ for (desc = bdrv_runtime_opts.desc; desc->name; desc++) { if (!strcmp(qdict_entry_key(entry), desc->name)) { break; } } if (desc->name) { continue; } qobject_incref(qdict_entry_value(entry)); qdict_put_obj(d, qdict_entry_key(entry), qdict_entry_value(entry)); found_any = true; } return found_any; } /* Updates the following BDS fields: * - exact_filename: A filename which may be used for opening a block device * which (mostly) equals the given BDS (even without any * other options; so reading and writing must return the same * results, but caching etc. may be different) * - full_open_options: Options which, when given when opening a block device * (without a filename), result in a BDS (mostly) * equalling the given one * - filename: If exact_filename is set, it is copied here. Otherwise, * full_open_options is converted to a JSON object, prefixed with * "json:" (for use through the JSON pseudo protocol) and put here. */ void bdrv_refresh_filename(BlockDriverState *bs) { BlockDriver *drv = bs->drv; QDict *opts; if (!drv) { return; } /* This BDS's file name will most probably depend on its file's name, so * refresh that first */ if (bs->file) { bdrv_refresh_filename(bs->file->bs); } if (drv->bdrv_refresh_filename) { /* Obsolete information is of no use here, so drop the old file name * information before refreshing it */ bs->exact_filename[0] = '\0'; if (bs->full_open_options) { QDECREF(bs->full_open_options); bs->full_open_options = NULL; } opts = qdict_new(); append_open_options(opts, bs); drv->bdrv_refresh_filename(bs, opts); QDECREF(opts); } else if (bs->file) { /* Try to reconstruct valid information from the underlying file */ bool has_open_options; bs->exact_filename[0] = '\0'; if (bs->full_open_options) { QDECREF(bs->full_open_options); bs->full_open_options = NULL; } opts = qdict_new(); has_open_options = append_open_options(opts, bs); /* If no specific options have been given for this BDS, the filename of * the underlying file should suffice for this one as well */ if (bs->file->bs->exact_filename[0] && !has_open_options) { strcpy(bs->exact_filename, bs->file->bs->exact_filename); } /* Reconstructing the full options QDict is simple for most format block * drivers, as long as the full options are known for the underlying * file BDS. The full options QDict of that file BDS should somehow * contain a representation of the filename, therefore the following * suffices without querying the (exact_)filename of this BDS. */ if (bs->file->bs->full_open_options) { qdict_put_obj(opts, "driver", QOBJECT(qstring_from_str(drv->format_name))); QINCREF(bs->file->bs->full_open_options); qdict_put_obj(opts, "file", QOBJECT(bs->file->bs->full_open_options)); bs->full_open_options = opts; } else { QDECREF(opts); } } else if (!bs->full_open_options && qdict_size(bs->options)) { /* There is no underlying file BDS (at least referenced by BDS.file), * so the full options QDict should be equal to the options given * specifically for this block device when it was opened (plus the * driver specification). * Because those options don't change, there is no need to update * full_open_options when it's already set. */ opts = qdict_new(); append_open_options(opts, bs); qdict_put_obj(opts, "driver", QOBJECT(qstring_from_str(drv->format_name))); if (bs->exact_filename[0]) { /* This may not work for all block protocol drivers (some may * require this filename to be parsed), but we have to find some * default solution here, so just include it. If some block driver * does not support pure options without any filename at all or * needs some special format of the options QDict, it needs to * implement the driver-specific bdrv_refresh_filename() function. */ qdict_put_obj(opts, "filename", QOBJECT(qstring_from_str(bs->exact_filename))); } bs->full_open_options = opts; } if (bs->exact_filename[0]) { pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename); } else if (bs->full_open_options) { QString *json = qobject_to_json(QOBJECT(bs->full_open_options)); snprintf(bs->filename, sizeof(bs->filename), "json:%s", qstring_get_str(json)); QDECREF(json); } }