/* * 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 "block/trace.h" #include "block/block_int.h" #include "block/blockjob.h" #include "block/nbd.h" #include "qemu/error-report.h" #include "module_block.h" #include "qemu/module.h" #include "qapi/error.h" #include "qapi/qmp/qdict.h" #include "qapi/qmp/qjson.h" #include "qapi/qmp/qstring.h" #include "sysemu/block-backend.h" #include "sysemu/sysemu.h" #include "qemu/notify.h" #include "qemu/option.h" #include "qemu/coroutine.h" #include "block/qapi.h" #include "qemu/timer.h" #include "qemu/cutils.h" #include "qemu/id.h" #ifdef CONFIG_BSD #include <sys/ioctl.h> #include <sys/queue.h> #ifndef __DragonFly__ #include <sys/disk.h> #endif #endif #ifdef _WIN32 #include <windows.h> #endif #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ 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 BlockDriverState *bdrv_open_inherit(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; #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 "<protocol>:" */ 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 { const char *protocol_stripped = NULL; if (path_has_protocol(base_path)) { protocol_stripped = strchr(base_path, ':'); if (protocol_stripped) { protocol_stripped++; } } p = protocol_stripped ?: 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); } } /* * Helper function for bdrv_parse_filename() implementations to remove optional * protocol prefixes (especially "file:") from a filename and for putting the * stripped filename into the options QDict if there is such a prefix. */ void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, QDict *options) { if (strstart(filename, prefix, &filename)) { /* Stripping the explicit protocol prefix may result in a protocol * prefix being (wrongly) detected (if the filename contains a colon) */ if (path_has_protocol(filename)) { QString *fat_filename; /* This means there is some colon before the first slash; therefore, * this cannot be an absolute path */ assert(!path_is_absolute(filename)); /* And we can thus fix the protocol detection issue by prefixing it * by "./" */ fat_filename = qstring_from_str("./"); qstring_append(fat_filename, filename); assert(!path_has_protocol(qstring_get_str(fat_filename))); qdict_put(options, "filename", fat_filename); } else { /* If no protocol prefix was detected, we can use the shortened * filename as-is */ qdict_put_str(options, "filename", filename); } } } /* Returns whether the image file is opened as read-only. Note that this can * return false and writing to the image file is still not possible because the * image is inactivated. */ bool bdrv_is_read_only(BlockDriverState *bs) { return bs->read_only; } int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, bool ignore_allow_rdw, Error **errp) { /* Do not set read_only if copy_on_read is enabled */ if (bs->copy_on_read && read_only) { error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled", bdrv_get_device_or_node_name(bs)); return -EINVAL; } /* Do not clear read_only if it is prohibited */ if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR) && !ignore_allow_rdw) { error_setg(errp, "Node '%s' is read only", bdrv_get_device_or_node_name(bs)); return -EPERM; } return 0; } /* TODO Remove (deprecated since 2.11) * Block drivers are not supposed to automatically change bs->read_only. * Instead, they should just check whether they can provide what the user * explicitly requested and error out if read-write is requested, but they can * only provide read-only access. */ int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp) { int ret = 0; ret = bdrv_can_set_read_only(bs, read_only, false, errp); if (ret < 0) { return ret; } bs->read_only = read_only; return 0; } 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) { QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list); } 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_mutex_init(&bs->reqs_lock); qemu_mutex_init(&bs->dirty_bitmap_mutex); bs->refcnt = 1; bs->aio_context = qemu_get_aio_context(); qemu_co_queue_init(&bs->flush_queue); QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list); return bs; } static BlockDriver *bdrv_do_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; } BlockDriver *bdrv_find_format(const char *format_name) { BlockDriver *drv1; int i; drv1 = bdrv_do_find_format(format_name); if (drv1) { return drv1; } /* The driver isn't registered, maybe we need to load a module */ for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) { if (!strcmp(block_driver_modules[i].format_name, format_name)) { block_module_load_one(block_driver_modules[i].library_name); break; } } return bdrv_do_find_format(format_name); } 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; } bool bdrv_uses_whitelist(void) { return use_bdrv_whitelist; } 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_co_create_opts(cco->filename, cco->opts, &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_co_create_opts) { 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, &cco); qemu_coroutine_enter(co); 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); 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); } else if (drv && drv->is_filter && bs->file) { return bdrv_probe_blocksizes(bs->file->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); } else if (drv && drv->is_filter && bs->file) { return bdrv_probe_geometry(bs->file->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; } static BlockDriver *bdrv_do_find_protocol(const char *protocol) { BlockDriver *drv1; QLIST_FOREACH(drv1, &bdrv_drivers, list) { if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) { return drv1; } } return NULL; } BlockDriver *bdrv_find_protocol(const char *filename, bool allow_protocol_prefix, Error **errp) { BlockDriver *drv1; char protocol[128]; int len; const char *p; int i; /* 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'; drv1 = bdrv_do_find_protocol(protocol); if (drv1) { return drv1; } for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) { if (block_driver_modules[i].protocol_name && !strcmp(block_driver_modules[i].protocol_name, protocol)) { block_module_load_one(block_driver_modules[i].library_name); break; } } drv1 = bdrv_do_find_protocol(protocol); if (!drv1) { error_setg(errp, "Unknown protocol '%s'", protocol); } return drv1; } /* * 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(BlockBackend *file, 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 (blk_is_sg(file) || !blk_is_inserted(file) || blk_getlength(file) == 0) { *pdrv = &bdrv_raw; return ret; } ret = blk_pread(file, 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; if (!drv) { return -ENOMEDIUM; } /* 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_mode(const char *mode, int *flags, bool *writethrough) { *flags &= ~BDRV_O_CACHE_MASK; if (!strcmp(mode, "off") || !strcmp(mode, "none")) { *writethrough = false; *flags |= BDRV_O_NOCACHE; } else if (!strcmp(mode, "directsync")) { *writethrough = true; *flags |= BDRV_O_NOCACHE; } else if (!strcmp(mode, "writeback")) { *writethrough = false; } else if (!strcmp(mode, "unsafe")) { *writethrough = false; *flags |= BDRV_O_NO_FLUSH; } else if (!strcmp(mode, "writethrough")) { *writethrough = true; } else { return -1; } return 0; } static char *bdrv_child_get_parent_desc(BdrvChild *c) { BlockDriverState *parent = c->opaque; return g_strdup(bdrv_get_device_or_node_name(parent)); } static void bdrv_child_cb_drained_begin(BdrvChild *child) { BlockDriverState *bs = child->opaque; bdrv_drained_begin(bs); } static void bdrv_child_cb_drained_end(BdrvChild *child) { BlockDriverState *bs = child->opaque; bdrv_drained_end(bs); } static void bdrv_child_cb_attach(BdrvChild *child) { BlockDriverState *bs = child->opaque; bdrv_apply_subtree_drain(child, bs); } static void bdrv_child_cb_detach(BdrvChild *child) { BlockDriverState *bs = child->opaque; bdrv_unapply_subtree_drain(child, bs); } static int bdrv_child_cb_inactivate(BdrvChild *child) { BlockDriverState *bs = child->opaque; assert(bs->open_flags & BDRV_O_INACTIVE); 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_DIRECT, "off"); qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on"); /* Copy the read-only option from the parent */ qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY); /* aio=native doesn't work for cache.direct=off, so disable it for the * temporary snapshot */ *child_flags &= ~BDRV_O_NATIVE_AIO; } /* * 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); qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE); /* Inherit the read-only option from the parent if it's not set */ qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY); /* 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_DISCARD, "unmap"); /* Clear flags that only apply to the top layer */ flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ | BDRV_O_NO_IO); *child_flags = flags; } const BdrvChildRole child_file = { .get_parent_desc = bdrv_child_get_parent_desc, .inherit_options = bdrv_inherited_options, .drained_begin = bdrv_child_cb_drained_begin, .drained_end = bdrv_child_cb_drained_end, .attach = bdrv_child_cb_attach, .detach = bdrv_child_cb_detach, .inactivate = bdrv_child_cb_inactivate, }; /* * 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 | BDRV_O_NO_IO); } const BdrvChildRole child_format = { .get_parent_desc = bdrv_child_get_parent_desc, .inherit_options = bdrv_inherited_fmt_options, .drained_begin = bdrv_child_cb_drained_begin, .drained_end = bdrv_child_cb_drained_end, .attach = bdrv_child_cb_attach, .detach = bdrv_child_cb_detach, .inactivate = bdrv_child_cb_inactivate, }; static void bdrv_backing_attach(BdrvChild *c) { BlockDriverState *parent = c->opaque; BlockDriverState *backing_hd = c->bs; assert(!parent->backing_blocker); error_setg(&parent->backing_blocker, "node is used as backing hd of '%s'", bdrv_get_device_or_node_name(parent)); parent->open_flags &= ~BDRV_O_NO_BACKING; pstrcpy(parent->backing_file, sizeof(parent->backing_file), backing_hd->filename); pstrcpy(parent->backing_format, sizeof(parent->backing_format), backing_hd->drv ? backing_hd->drv->format_name : ""); bdrv_op_block_all(backing_hd, parent->backing_blocker); /* Otherwise we won't be able to commit or stream */ bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET, parent->backing_blocker); bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM, parent->backing_blocker); /* * We do backup in 3 ways: * 1. drive backup * The target bs is new opened, and the source is top BDS * 2. blockdev backup * Both the source and the target are top BDSes. * 3. internal backup(used for block replication) * Both the source and the target are backing file * * In case 1 and 2, neither the source nor the target is the backing file. * In case 3, we will block the top BDS, so there is only one block job * for the top BDS and its backing chain. */ bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE, parent->backing_blocker); bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET, parent->backing_blocker); bdrv_child_cb_attach(c); } static void bdrv_backing_detach(BdrvChild *c) { BlockDriverState *parent = c->opaque; assert(parent->backing_blocker); bdrv_op_unblock_all(c->bs, parent->backing_blocker); error_free(parent->backing_blocker); parent->backing_blocker = NULL; bdrv_child_cb_detach(c); } /* * 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; except WCE, * which is only applied on the top level (BlockBackend) */ qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT); qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH); qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE); /* backing files always opened read-only */ qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on"); flags &= ~BDRV_O_COPY_ON_READ; /* snapshot=on is handled on the top layer */ flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY); *child_flags = flags; } static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base, const char *filename, Error **errp) { BlockDriverState *parent = c->opaque; int orig_flags = bdrv_get_flags(parent); int ret; if (!(orig_flags & BDRV_O_RDWR)) { ret = bdrv_reopen(parent, orig_flags | BDRV_O_RDWR, errp); if (ret < 0) { return ret; } } ret = bdrv_change_backing_file(parent, filename, base->drv ? base->drv->format_name : ""); if (ret < 0) { error_setg_errno(errp, -ret, "Could not update backing file link"); } if (!(orig_flags & BDRV_O_RDWR)) { bdrv_reopen(parent, orig_flags, NULL); } return ret; } const BdrvChildRole child_backing = { .get_parent_desc = bdrv_child_get_parent_desc, .attach = bdrv_backing_attach, .detach = bdrv_backing_detach, .inherit_options = bdrv_backing_options, .drained_begin = bdrv_child_cb_drained_begin, .drained_end = bdrv_child_cb_drained_end, .inactivate = bdrv_child_cb_inactivate, .update_filename = bdrv_backing_update_filename, }; static int bdrv_open_flags(BlockDriverState *bs, int flags) { int open_flags = flags; /* * 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_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; } *flags &= ~BDRV_O_RDWR; assert(qemu_opt_find(opts, BDRV_OPT_READ_ONLY)); if (!qemu_opt_get_bool(opts, BDRV_OPT_READ_ONLY, false)) { *flags |= BDRV_O_RDWR; } } static void update_options_from_flags(QDict *options, int flags) { if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) { qdict_put_bool(options, BDRV_OPT_CACHE_DIRECT, flags & BDRV_O_NOCACHE); } if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) { qdict_put_bool(options, BDRV_OPT_CACHE_NO_FLUSH, flags & BDRV_O_NO_FLUSH); } if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) { qdict_put_bool(options, BDRV_OPT_READ_ONLY, !(flags & BDRV_O_RDWR)); } } 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 int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv, const char *node_name, QDict *options, int open_flags, Error **errp) { Error *local_err = NULL; int ret; bdrv_assign_node_name(bs, node_name, &local_err); if (local_err) { error_propagate(errp, local_err); return -EINVAL; } bs->drv = drv; bs->read_only = !(bs->open_flags & BDRV_O_RDWR); bs->opaque = g_malloc0(drv->instance_size); if (drv->bdrv_file_open) { assert(!drv->bdrv_needs_filename || bs->filename[0]); ret = drv->bdrv_file_open(bs, options, open_flags, &local_err); } else if (drv->bdrv_open) { ret = drv->bdrv_open(bs, options, open_flags, &local_err); } else { ret = 0; } 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 open_failed; } ret = refresh_total_sectors(bs, bs->total_sectors); if (ret < 0) { error_setg_errno(errp, -ret, "Could not refresh total sector count"); return ret; } bdrv_refresh_limits(bs, &local_err); if (local_err) { error_propagate(errp, local_err); return -EINVAL; } assert(bdrv_opt_mem_align(bs) != 0); assert(bdrv_min_mem_align(bs) != 0); assert(is_power_of_2(bs->bl.request_alignment)); return 0; open_failed: bs->drv = NULL; if (bs->file != NULL) { bdrv_unref_child(bs, bs->file); bs->file = NULL; } g_free(bs->opaque); bs->opaque = NULL; return ret; } BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name, int flags, Error **errp) { BlockDriverState *bs; int ret; bs = bdrv_new(); bs->open_flags = flags; bs->explicit_options = qdict_new(); bs->options = qdict_new(); bs->opaque = NULL; update_options_from_flags(bs->options, flags); ret = bdrv_open_driver(bs, drv, node_name, bs->options, flags, errp); if (ret < 0) { QDECREF(bs->explicit_options); bs->explicit_options = NULL; QDECREF(bs->options); bs->options = NULL; bdrv_unref(bs); return NULL; } return bs; } 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_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", }, { .name = BDRV_OPT_READ_ONLY, .type = QEMU_OPT_BOOL, .help = "Node is opened in read-only mode", }, { .name = "detect-zeroes", .type = QEMU_OPT_STRING, .help = "try to optimize zero writes (off, on, unmap)", }, { .name = "discard", .type = QEMU_OPT_STRING, .help = "discard operation (ignore/off, unmap/on)", }, { .name = BDRV_OPT_FORCE_SHARE, .type = QEMU_OPT_BOOL, .help = "always accept other writers (default: off)", }, { /* end of list */ } }, }; /* * Common part for opening disk images and files * * Removes all processed options from *options. */ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file, QDict *options, Error **errp) { int ret, open_flags; const char *filename; const char *driver_name = NULL; const char *node_name = NULL; const char *discard; const char *detect_zeroes; 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; } update_flags_from_options(&bs->open_flags, opts); driver_name = qemu_opt_get(opts, "driver"); drv = bdrv_find_format(driver_name); assert(drv != NULL); bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false); if (bs->force_share && (bs->open_flags & BDRV_O_RDWR)) { error_setg(errp, BDRV_OPT_FORCE_SHARE "=on can only be used with read-only images"); ret = -EINVAL; goto fail_opts; } if (file != NULL) { filename = blk_bs(file)->filename; } else { /* * Caution: while qdict_get_try_str() is fine, getting * non-string types would require more care. When @options * come from -blockdev or blockdev_add, its members are typed * according to the QAPI schema, but when they come from * -drive, they're all QString. */ filename = qdict_get_try_str(options, "filename"); } if (drv->bdrv_needs_filename && (!filename || !filename[0])) { 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); 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; } /* bdrv_new() and bdrv_close() make it so */ assert(atomic_read(&bs->copy_on_read) == 0); 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; } } discard = qemu_opt_get(opts, "discard"); if (discard != NULL) { if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) { error_setg(errp, "Invalid discard option"); ret = -EINVAL; goto fail_opts; } } detect_zeroes = qemu_opt_get(opts, "detect-zeroes"); if (detect_zeroes) { BlockdevDetectZeroesOptions value = qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup, detect_zeroes, BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF, &local_err); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto fail_opts; } if (value == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP && !(bs->open_flags & BDRV_O_UNMAP)) { error_setg(errp, "setting detect-zeroes to unmap is not allowed " "without setting discard operation to unmap"); ret = -EINVAL; goto fail_opts; } bs->detect_zeroes = value; } 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); /* Open the image, either directly or using a protocol */ open_flags = bdrv_open_flags(bs, bs->open_flags); node_name = qemu_opt_get(opts, "node-name"); assert(!drv->bdrv_file_open || file == NULL); ret = bdrv_open_driver(bs, drv, node_name, options, open_flags, errp); if (ret < 0) { goto fail_opts; } qemu_opts_del(opts); return 0; 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, errp); if (!options_obj) { /* Work around qobject_from_json() lossage TODO fix that */ if (errp && !*errp) { error_setg(errp, "Could not parse the JSON options"); return NULL; } error_prepend(errp, "Could not parse the JSON options: "); return NULL; } options = qobject_to_qdict(options_obj); if (!options) { qobject_decref(options_obj); error_setg(errp, "Invalid JSON object given"); return NULL; } 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; /* * Caution: while qdict_get_try_str() is fine, getting non-string * types would require more care. When @options come from * -blockdev or blockdev_add, its members are typed according to * the QAPI schema, but when they come from -drive, they're all * QString. */ 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_str(*options, "filename", 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 */ /* See cautionary note on accessing @options above */ 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_str(*options, "driver", 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 int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, uint64_t perm, uint64_t shared, GSList *ignore_children, Error **errp); static void bdrv_child_abort_perm_update(BdrvChild *c); static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); typedef struct BlockReopenQueueEntry { bool prepared; BDRVReopenState state; QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; } BlockReopenQueueEntry; /* * Return the flags that @bs will have after the reopens in @q have * successfully completed. If @q is NULL (or @bs is not contained in @q), * return the current flags. */ static int bdrv_reopen_get_flags(BlockReopenQueue *q, BlockDriverState *bs) { BlockReopenQueueEntry *entry; if (q != NULL) { QSIMPLEQ_FOREACH(entry, q, entry) { if (entry->state.bs == bs) { return entry->state.flags; } } } return bs->open_flags; } /* Returns whether the image file can be written to after the reopen queue @q * has been successfully applied, or right now if @q is NULL. */ static bool bdrv_is_writable(BlockDriverState *bs, BlockReopenQueue *q) { int flags = bdrv_reopen_get_flags(q, bs); return (flags & (BDRV_O_RDWR | BDRV_O_INACTIVE)) == BDRV_O_RDWR; } static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs, BdrvChild *c, const BdrvChildRole *role, BlockReopenQueue *reopen_queue, uint64_t parent_perm, uint64_t parent_shared, uint64_t *nperm, uint64_t *nshared) { if (bs->drv && bs->drv->bdrv_child_perm) { bs->drv->bdrv_child_perm(bs, c, role, reopen_queue, parent_perm, parent_shared, nperm, nshared); } /* TODO Take force_share from reopen_queue */ if (child_bs && child_bs->force_share) { *nshared = BLK_PERM_ALL; } } /* * Check whether permissions on this node can be changed in a way that * @cumulative_perms and @cumulative_shared_perms are the new cumulative * permissions of all its parents. This involves checking whether all necessary * permission changes to child nodes can be performed. * * A call to this function must always be followed by a call to bdrv_set_perm() * or bdrv_abort_perm_update(). */ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, uint64_t cumulative_perms, uint64_t cumulative_shared_perms, GSList *ignore_children, Error **errp) { BlockDriver *drv = bs->drv; BdrvChild *c; int ret; /* Write permissions never work with read-only images */ if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) && !bdrv_is_writable(bs, q)) { error_setg(errp, "Block node is read-only"); return -EPERM; } /* Check this node */ if (!drv) { return 0; } if (drv->bdrv_check_perm) { return drv->bdrv_check_perm(bs, cumulative_perms, cumulative_shared_perms, errp); } /* Drivers that never have children can omit .bdrv_child_perm() */ if (!drv->bdrv_child_perm) { assert(QLIST_EMPTY(&bs->children)); return 0; } /* Check all children */ QLIST_FOREACH(c, &bs->children, next) { uint64_t cur_perm, cur_shared; bdrv_child_perm(bs, c->bs, c, c->role, q, cumulative_perms, cumulative_shared_perms, &cur_perm, &cur_shared); ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, ignore_children, errp); if (ret < 0) { return ret; } } return 0; } /* * Notifies drivers that after a previous bdrv_check_perm() call, the * permission update is not performed and any preparations made for it (e.g. * taken file locks) need to be undone. * * This function recursively notifies all child nodes. */ static void bdrv_abort_perm_update(BlockDriverState *bs) { BlockDriver *drv = bs->drv; BdrvChild *c; if (!drv) { return; } if (drv->bdrv_abort_perm_update) { drv->bdrv_abort_perm_update(bs); } QLIST_FOREACH(c, &bs->children, next) { bdrv_child_abort_perm_update(c); } } static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms, uint64_t cumulative_shared_perms) { BlockDriver *drv = bs->drv; BdrvChild *c; if (!drv) { return; } /* Update this node */ if (drv->bdrv_set_perm) { drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms); } /* Drivers that never have children can omit .bdrv_child_perm() */ if (!drv->bdrv_child_perm) { assert(QLIST_EMPTY(&bs->children)); return; } /* Update all children */ QLIST_FOREACH(c, &bs->children, next) { uint64_t cur_perm, cur_shared; bdrv_child_perm(bs, c->bs, c, c->role, NULL, cumulative_perms, cumulative_shared_perms, &cur_perm, &cur_shared); bdrv_child_set_perm(c, cur_perm, cur_shared); } } static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, uint64_t *shared_perm) { BdrvChild *c; uint64_t cumulative_perms = 0; uint64_t cumulative_shared_perms = BLK_PERM_ALL; QLIST_FOREACH(c, &bs->parents, next_parent) { cumulative_perms |= c->perm; cumulative_shared_perms &= c->shared_perm; } *perm = cumulative_perms; *shared_perm = cumulative_shared_perms; } static char *bdrv_child_user_desc(BdrvChild *c) { if (c->role->get_parent_desc) { return c->role->get_parent_desc(c); } return g_strdup("another user"); } char *bdrv_perm_names(uint64_t perm) { struct perm_name { uint64_t perm; const char *name; } permissions[] = { { BLK_PERM_CONSISTENT_READ, "consistent read" }, { BLK_PERM_WRITE, "write" }, { BLK_PERM_WRITE_UNCHANGED, "write unchanged" }, { BLK_PERM_RESIZE, "resize" }, { BLK_PERM_GRAPH_MOD, "change children" }, { 0, NULL } }; char *result = g_strdup(""); struct perm_name *p; for (p = permissions; p->name; p++) { if (perm & p->perm) { char *old = result; result = g_strdup_printf("%s%s%s", old, *old ? ", " : "", p->name); g_free(old); } } return result; } /* * Checks whether a new reference to @bs can be added if the new user requires * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is * set, the BdrvChild objects in this list are ignored in the calculations; * this allows checking permission updates for an existing reference. * * Needs to be followed by a call to either bdrv_set_perm() or * bdrv_abort_perm_update(). */ static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, uint64_t new_used_perm, uint64_t new_shared_perm, GSList *ignore_children, Error **errp) { BdrvChild *c; uint64_t cumulative_perms = new_used_perm; uint64_t cumulative_shared_perms = new_shared_perm; /* There is no reason why anyone couldn't tolerate write_unchanged */ assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED); QLIST_FOREACH(c, &bs->parents, next_parent) { if (g_slist_find(ignore_children, c)) { continue; } if ((new_used_perm & c->shared_perm) != new_used_perm) { char *user = bdrv_child_user_desc(c); char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm); error_setg(errp, "Conflicts with use by %s as '%s', which does not " "allow '%s' on %s", user, c->name, perm_names, bdrv_get_node_name(c->bs)); g_free(user); g_free(perm_names); return -EPERM; } if ((c->perm & new_shared_perm) != c->perm) { char *user = bdrv_child_user_desc(c); char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm); error_setg(errp, "Conflicts with use by %s as '%s', which uses " "'%s' on %s", user, c->name, perm_names, bdrv_get_node_name(c->bs)); g_free(user); g_free(perm_names); return -EPERM; } cumulative_perms |= c->perm; cumulative_shared_perms &= c->shared_perm; } return bdrv_check_perm(bs, q, cumulative_perms, cumulative_shared_perms, ignore_children, errp); } /* Needs to be followed by a call to either bdrv_child_set_perm() or * bdrv_child_abort_perm_update(). */ static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, uint64_t perm, uint64_t shared, GSList *ignore_children, Error **errp) { int ret; ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c); ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children, errp); g_slist_free(ignore_children); return ret; } static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared) { uint64_t cumulative_perms, cumulative_shared_perms; c->perm = perm; c->shared_perm = shared; bdrv_get_cumulative_perm(c->bs, &cumulative_perms, &cumulative_shared_perms); bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms); } static void bdrv_child_abort_perm_update(BdrvChild *c) { bdrv_abort_perm_update(c->bs); } int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, Error **errp) { int ret; ret = bdrv_child_check_perm(c, NULL, perm, shared, NULL, errp); if (ret < 0) { bdrv_child_abort_perm_update(c); return ret; } bdrv_child_set_perm(c, perm, shared); return 0; } #define DEFAULT_PERM_PASSTHROUGH (BLK_PERM_CONSISTENT_READ \ | BLK_PERM_WRITE \ | BLK_PERM_WRITE_UNCHANGED \ | BLK_PERM_RESIZE) #define DEFAULT_PERM_UNCHANGED (BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH) void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, const BdrvChildRole *role, BlockReopenQueue *reopen_queue, uint64_t perm, uint64_t shared, uint64_t *nperm, uint64_t *nshared) { if (c == NULL) { *nperm = perm & DEFAULT_PERM_PASSTHROUGH; *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED; return; } *nperm = (perm & DEFAULT_PERM_PASSTHROUGH) | (c->perm & DEFAULT_PERM_UNCHANGED); *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | (c->shared_perm & DEFAULT_PERM_UNCHANGED); } void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, const BdrvChildRole *role, BlockReopenQueue *reopen_queue, uint64_t perm, uint64_t shared, uint64_t *nperm, uint64_t *nshared) { bool backing = (role == &child_backing); assert(role == &child_backing || role == &child_file); if (!backing) { int flags = bdrv_reopen_get_flags(reopen_queue, bs); /* Apart from the modifications below, the same permissions are * forwarded and left alone as for filters */ bdrv_filter_default_perms(bs, c, role, reopen_queue, perm, shared, &perm, &shared); /* Format drivers may touch metadata even if the guest doesn't write */ if (bdrv_is_writable(bs, reopen_queue)) { perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE; } /* bs->file always needs to be consistent because of the metadata. We * can never allow other users to resize or write to it. */ if (!(flags & BDRV_O_NO_IO)) { perm |= BLK_PERM_CONSISTENT_READ; } shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); } else { /* We want consistent read from backing files if the parent needs it. * No other operations are performed on backing files. */ perm &= BLK_PERM_CONSISTENT_READ; /* If the parent can deal with changing data, we're okay with a * writable and resizable backing file. */ /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */ if (shared & BLK_PERM_WRITE) { shared = BLK_PERM_WRITE | BLK_PERM_RESIZE; } else { shared = 0; } shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD | BLK_PERM_WRITE_UNCHANGED; } if (bs->open_flags & BDRV_O_INACTIVE) { shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE; } *nperm = perm; *nshared = shared; } static void bdrv_replace_child_noperm(BdrvChild *child, BlockDriverState *new_bs) { BlockDriverState *old_bs = child->bs; int i; if (old_bs && new_bs) { assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs)); } if (old_bs) { /* Detach first so that the recursive drain sections coming from @child * are already gone and we only end the drain sections that came from * elsewhere. */ if (child->role->detach) { child->role->detach(child); } if (old_bs->quiesce_counter && child->role->drained_end) { for (i = 0; i < old_bs->quiesce_counter; i++) { child->role->drained_end(child); } } QLIST_REMOVE(child, next_parent); } child->bs = new_bs; if (new_bs) { QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); if (new_bs->quiesce_counter && child->role->drained_begin) { for (i = 0; i < new_bs->quiesce_counter; i++) { child->role->drained_begin(child); } } /* Attach only after starting new drained sections, so that recursive * drain sections coming from @child don't get an extra .drained_begin * callback. */ if (child->role->attach) { child->role->attach(child); } } } /* * Updates @child to change its reference to point to @new_bs, including * checking and applying the necessary permisson updates both to the old node * and to @new_bs. * * NULL is passed as @new_bs for removing the reference before freeing @child. * * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this * function uses bdrv_set_perm() to update the permissions according to the new * reference that @new_bs gets. */ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) { BlockDriverState *old_bs = child->bs; uint64_t perm, shared_perm; bdrv_replace_child_noperm(child, new_bs); if (old_bs) { /* Update permissions for old node. This is guaranteed to succeed * because we're just taking a parent away, so we're loosening * restrictions. */ bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm); bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL, &error_abort); bdrv_set_perm(old_bs, perm, shared_perm); } if (new_bs) { bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm); bdrv_set_perm(new_bs, perm, shared_perm); } } BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, const char *child_name, const BdrvChildRole *child_role, uint64_t perm, uint64_t shared_perm, void *opaque, Error **errp) { BdrvChild *child; int ret; ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp); if (ret < 0) { bdrv_abort_perm_update(child_bs); return NULL; } child = g_new(BdrvChild, 1); *child = (BdrvChild) { .bs = NULL, .name = g_strdup(child_name), .role = child_role, .perm = perm, .shared_perm = shared_perm, .opaque = opaque, }; /* This performs the matching bdrv_set_perm() for the above check. */ bdrv_replace_child(child, child_bs); return child; } BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, BlockDriverState *child_bs, const char *child_name, const BdrvChildRole *child_role, Error **errp) { BdrvChild *child; uint64_t perm, shared_perm; bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm); assert(parent_bs->drv); assert(bdrv_get_aio_context(parent_bs) == bdrv_get_aio_context(child_bs)); bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL, perm, shared_perm, &perm, &shared_perm); child = bdrv_root_attach_child(child_bs, child_name, child_role, perm, shared_perm, parent_bs, errp); if (child == NULL) { return NULL; } QLIST_INSERT_HEAD(&parent_bs->children, child, next); return child; } static void bdrv_detach_child(BdrvChild *child) { if (child->next.le_prev) { QLIST_REMOVE(child, next); child->next.le_prev = NULL; } bdrv_replace_child(child, NULL); g_free(child->name); g_free(child); } void bdrv_root_unref_child(BdrvChild *child) { BlockDriverState *child_bs; child_bs = child->bs; bdrv_detach_child(child); bdrv_unref(child_bs); } void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) { if (child == NULL) { return; } if (child->bs->inherits_from == parent) { BdrvChild *c; /* Remove inherits_from only when the last reference between parent and * child->bs goes away. */ QLIST_FOREACH(c, &parent->children, next) { if (c != child && c->bs == child->bs) { break; } } if (c == NULL) { child->bs->inherits_from = NULL; } } bdrv_root_unref_child(child); } static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load) { BdrvChild *c; QLIST_FOREACH(c, &bs->parents, next_parent) { if (c->role->change_media) { c->role->change_media(c, load); } } } static void bdrv_parent_cb_resize(BlockDriverState *bs) { BdrvChild *c; QLIST_FOREACH(c, &bs->parents, next_parent) { if (c->role->resize) { c->role->resize(c); } } } /* * 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, Error **errp) { if (backing_hd) { bdrv_ref(backing_hd); } if (bs->backing) { bdrv_unref_child(bs, bs->backing); } if (!backing_hd) { bs->backing = NULL; goto out; } bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing, errp); if (!bs->backing) { bdrv_unref(backing_hd); } bdrv_refresh_filename(bs); 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); /* * Caution: while qdict_get_try_str() is fine, getting non-string * types would require more care. When @parent_options come from * -blockdev or blockdev_add, its members are typed according to * the QAPI schema, but when they come from -drive, they're all * QString. */ 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 (!reference && bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) { qdict_put_str(options, "driver", bs->backing_format); } backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL, reference, options, 0, bs, &child_backing, errp); if (!backing_hd) { bs->open_flags |= BDRV_O_NO_BACKING; error_prepend(errp, "Could not open backing file: "); ret = -EINVAL; goto free_exit; } bdrv_set_aio_context(backing_hd, bdrv_get_aio_context(bs)); /* Hook up the backing file link; drop our reference, bs owns the * backing_hd reference now */ bdrv_set_backing_hd(bs, backing_hd, &local_err); bdrv_unref(backing_hd); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto free_exit; } qdict_del(parent_options, bdref_key); free_exit: g_free(backing_filename); QDECREF(tmp_parent_options); return ret; } static BlockDriverState * bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key, BlockDriverState *parent, const BdrvChildRole *child_role, bool allow_none, Error **errp) { BlockDriverState *bs = NULL; QDict *image_options; 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); /* * Caution: while qdict_get_try_str() is fine, getting non-string * types would require more care. When @options come from * -blockdev or blockdev_add, its members are typed according to * the QAPI schema, but when they come from -drive, they're all * QString. */ 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 = bdrv_open_inherit(filename, reference, image_options, 0, parent, child_role, errp); if (!bs) { goto done; } done: qdict_del(options, bdref_key); return bs; } /* * 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; BlockDriverState *bs; bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role, allow_none, errp); if (bs == NULL) { return NULL; } c = bdrv_attach_child(parent, bs, bdref_key, child_role, errp); if (!c) { bdrv_unref(bs); return NULL; } return c; } static BlockDriverState *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 = NULL; 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) { 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_str(snapshot_options, "file.driver", "file"); qdict_put_str(snapshot_options, "file.filename", tmp_filename); qdict_put_str(snapshot_options, "driver", "qcow2"); bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp); snapshot_options = NULL; if (!bs_snapshot) { goto out; } /* bdrv_append() consumes a strong reference to bs_snapshot * (i.e. it will call bdrv_unref() on it) even on error, so in * order to be able to return one, we have to increase * bs_snapshot's refcount here */ bdrv_ref(bs_snapshot); bdrv_append(bs_snapshot, bs, &local_err); if (local_err) { error_propagate(errp, local_err); bs_snapshot = NULL; goto out; } out: QDECREF(snapshot_options); g_free(tmp_filename); return bs_snapshot; } /* * 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 BlockDriverState *bdrv_open_inherit(const char *filename, const char *reference, QDict *options, int flags, BlockDriverState *parent, const BdrvChildRole *child_role, Error **errp) { int ret; BlockBackend *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(!child_role || !flags); assert(!child_role == !parent); if (reference) { bool options_non_empty = options ? qdict_size(options) : false; QDECREF(options); if (filename || options_non_empty) { error_setg(errp, "Cannot reference an existing block device with " "additional options or a new filename"); return NULL; } bs = bdrv_lookup_bs(reference, reference, errp); if (!bs) { return NULL; } bdrv_ref(bs); return bs; } 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) { 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; } /* * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags. * Caution: getting a boolean member of @options requires care. * When @options come from -blockdev or blockdev_add, members are * typed according to the QAPI schema, but when they come from * -drive, they're all QString. */ if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") && !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) { flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR); } else { flags &= ~BDRV_O_RDWR; } if (flags & BDRV_O_SNAPSHOT) { snapshot_options = qdict_new(); bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options, flags, options); /* Let bdrv_backing_options() override "read-only" */ qdict_del(options, BDRV_OPT_READ_ONLY); bdrv_backing_options(&flags, options, flags, options); } bs->open_flags = flags; bs->options = options; options = qdict_clone_shallow(options); /* Find the right image format driver */ /* See cautionary note on accessing @options above */ drvname = qdict_get_try_str(options, "driver"); if (drvname) { drv = bdrv_find_format(drvname); if (!drv) { error_setg(errp, "Unknown driver: '%s'", drvname); goto fail; } } assert(drvname || !(flags & BDRV_O_PROTOCOL)); /* See cautionary note on accessing @options above */ 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. This BlockBackend is only used for * probing, the block drivers will do their own bdrv_open_child() for the * same BDS, which is why we put the node name back into options. */ if ((flags & BDRV_O_PROTOCOL) == 0) { BlockDriverState *file_bs; file_bs = bdrv_open_child_bs(filename, options, "file", bs, &child_file, true, &local_err); if (local_err) { goto fail; } if (file_bs != NULL) { /* Not requesting BLK_PERM_CONSISTENT_READ because we're only * looking at the header to guess the image format. This works even * in cases where a guest would not see a consistent state. */ file = blk_new(0, BLK_PERM_ALL); blk_insert_bs(file, file_bs, &local_err); bdrv_unref(file_bs); if (local_err) { goto fail; } qdict_put_str(options, "file", bdrv_get_node_name(file_bs)); } } /* Image format probing */ bs->probed = !drv; if (!drv && file) { ret = find_image_format(file, 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_str(bs->options, "driver", drv->format_name); qdict_put_str(options, "driver", drv->format_name); } else if (!drv) { error_setg(errp, "Must specify either driver or file"); 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) { blk_unref(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 (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); } goto close_and_fail; } bdrv_parent_cb_change_media(bs, true); QDECREF(options); /* For snapshot=on, create a temporary qcow2 overlay. bs points to the * temporary snapshot afterwards. */ if (snapshot_flags) { BlockDriverState *snapshot_bs; snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags, snapshot_options, &local_err); snapshot_options = NULL; if (local_err) { goto close_and_fail; } /* We are not going to return bs but the overlay on top of it * (snapshot_bs); thus, we have to drop the strong reference to bs * (which we obtained by calling bdrv_new()). bs will not be deleted, * though, because the overlay still has a reference to it. */ bdrv_unref(bs); bs = snapshot_bs; } return bs; fail: blk_unref(file); QDECREF(snapshot_options); QDECREF(bs->explicit_options); QDECREF(bs->options); QDECREF(options); bs->options = NULL; bs->explicit_options = NULL; bdrv_unref(bs); error_propagate(errp, local_err); return NULL; close_and_fail: bdrv_unref(bs); QDECREF(snapshot_options); QDECREF(options); error_propagate(errp, local_err); return NULL; } BlockDriverState *bdrv_open(const char *filename, const char *reference, QDict *options, int flags, Error **errp) { return bdrv_open_inherit(filename, reference, options, flags, NULL, NULL, errp); } /* * 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. * * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple(). */ 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; /* Make sure that the caller remembered to use a drained section. This is * important to avoid graph changes between the recursive queuing here and * bdrv_reopen_multiple(). */ assert(bs->quiesce_counter > 0); if (bs_queue == NULL) { bs_queue = g_new0(BlockReopenQueue, 1); QSIMPLEQ_INIT(bs_queue); } if (!options) { options = qdict_new(); } /* Check if this BlockDriverState is already in the queue */ QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { if (bs == bs_entry->state.bs) { break; } } /* * 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) */ if (bs_entry) { old_options = qdict_clone_shallow(bs_entry->state.explicit_options); } else { 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_inherit() sets and clears some additional flags internally */ flags &= ~BDRV_O_PROTOCOL; if (flags & BDRV_O_RDWR) { flags |= BDRV_O_ALLOW_RDWR; } if (!bs_entry) { bs_entry = g_new0(BlockReopenQueueEntry, 1); QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry); } else { QDECREF(bs_entry->state.options); QDECREF(bs_entry->state.explicit_options); } bs_entry->state.bs = bs; bs_entry->state.options = options; bs_entry->state.explicit_options = explicit_options; bs_entry->state.flags = flags; /* This needs to be overwritten in bdrv_reopen_prepare() */ bs_entry->state.perm = UINT64_MAX; bs_entry->state.shared_perm = 0; 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); } 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. * * All affected nodes must be drained between bdrv_reopen_queue() and * bdrv_reopen_multiple(). */ int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp) { int ret = -1; BlockReopenQueueEntry *bs_entry, *next; Error *local_err = NULL; assert(bs_queue != NULL); QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { assert(bs_entry->state.bs->quiesce_counter > 0); 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_subtree_drained_begin(bs); queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags); ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, &local_err); if (local_err != NULL) { error_propagate(errp, local_err); } bdrv_subtree_drained_end(bs); return ret; } static BlockReopenQueueEntry *find_parent_in_reopen_queue(BlockReopenQueue *q, BdrvChild *c) { BlockReopenQueueEntry *entry; QSIMPLEQ_FOREACH(entry, q, entry) { BlockDriverState *bs = entry->state.bs; BdrvChild *child; QLIST_FOREACH(child, &bs->children, next) { if (child == c) { return entry; } } } return NULL; } static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs, uint64_t *perm, uint64_t *shared) { BdrvChild *c; BlockReopenQueueEntry *parent; uint64_t cumulative_perms = 0; uint64_t cumulative_shared_perms = BLK_PERM_ALL; QLIST_FOREACH(c, &bs->parents, next_parent) { parent = find_parent_in_reopen_queue(q, c); if (!parent) { cumulative_perms |= c->perm; cumulative_shared_perms &= c->shared_perm; } else { uint64_t nperm, nshared; bdrv_child_perm(parent->state.bs, bs, c, c->role, q, parent->state.perm, parent->state.shared_perm, &nperm, &nshared); cumulative_perms |= nperm; cumulative_shared_perms &= nshared; } } *perm = cumulative_perms; *shared = cumulative_shared_perms; } /* * 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; bool read_only; 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); /* 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_str(reopen_state->options, "node-name", value); } value = qemu_opt_get(opts, "driver"); if (value) { qdict_put_str(reopen_state->options, "driver", value); } /* If we are to stay read-only, do not allow permission change * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is * not set, or if the BDS still has copy_on_read enabled */ read_only = !(reopen_state->flags & BDRV_O_RDWR); ret = bdrv_can_set_read_only(reopen_state->bs, read_only, true, &local_err); if (local_err) { error_propagate(errp, local_err); goto error; } /* Calculate required permissions after reopening */ bdrv_reopen_perm(queue, reopen_state->bs, &reopen_state->perm, &reopen_state->shared_perm); 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 { QObject *new = entry->value; QObject *old = qdict_get(reopen_state->bs->options, entry->key); /* * TODO: When using -drive to specify blockdev options, all values * will be strings; however, when using -blockdev, blockdev-add or * filenames using the json:{} pseudo-protocol, they will be * correctly typed. * In contrast, reopening options are (currently) always strings * (because you can only specify them through qemu-io; all other * callers do not specify any options). * Therefore, when using anything other than -drive to create a BDS, * this cannot detect non-string options as unchanged, because * qobject_is_equal() always returns false for objects of different * type. In the future, this should be remedied by correctly typing * all options. For now, this is not too big of an issue because * the user can simply omit options which cannot be changed anyway, * so they will stay unchanged. */ if (!qobject_is_equal(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 = bdrv_check_perm(reopen_state->bs, queue, reopen_state->perm, reopen_state->shared_perm, NULL, errp); if (ret < 0) { goto error; } 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; BlockDriverState *bs; bool old_can_write, new_can_write; assert(reopen_state != NULL); bs = reopen_state->bs; drv = bs->drv; assert(drv != NULL); old_can_write = !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE); /* 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(bs->explicit_options); bs->explicit_options = reopen_state->explicit_options; bs->open_flags = reopen_state->flags; bs->read_only = !(reopen_state->flags & BDRV_O_RDWR); bdrv_refresh_limits(bs, NULL); bdrv_set_perm(reopen_state->bs, reopen_state->perm, reopen_state->shared_perm); new_can_write = !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE); if (!old_can_write && new_can_write && drv->bdrv_reopen_bitmaps_rw) { Error *local_err = NULL; if (drv->bdrv_reopen_bitmaps_rw(bs, &local_err) < 0) { /* This is not fatal, bitmaps just left read-only, so all following * writes will fail. User can remove read-only bitmaps to unblock * writes. */ error_reportf_err(local_err, "%s: Failed to make dirty bitmaps writable: ", bdrv_get_node_name(bs)); } } } /* * 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); bdrv_abort_perm_update(reopen_state->bs); } static void bdrv_close(BlockDriverState *bs) { BdrvAioNotifier *ban, *ban_next; BdrvChild *child, *next; assert(!bs->job); assert(!bs->refcnt); bdrv_drained_begin(bs); /* complete I/O */ bdrv_flush(bs); bdrv_drain(bs); /* in case flush left pending I/O */ if (bs->drv) { bs->drv->bdrv_close(bs); bs->drv = NULL; } bdrv_set_backing_hd(bs, NULL, &error_abort); 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; atomic_set(&bs->copy_on_read, 0); bs->backing_file[0] = '\0'; bs->backing_format[0] = '\0'; bs->total_sectors = 0; bs->encrypted = false; bs->sg = false; QDECREF(bs->options); QDECREF(bs->explicit_options); bs->options = NULL; bs->explicit_options = NULL; QDECREF(bs->full_open_options); bs->full_open_options = NULL; bdrv_release_named_dirty_bitmaps(bs); assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 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) { block_job_cancel_sync_all(); nbd_export_close_all(); /* 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(); assert(QTAILQ_EMPTY(&all_bdrv_states)); } static bool should_update_child(BdrvChild *c, BlockDriverState *to) { BdrvChild *to_c; if (c->role->stay_at_node) { return false; } if (c->role == &child_backing) { /* If @from is a backing file of @to, ignore the child to avoid * creating a loop. We only want to change the pointer of other * parents. */ QLIST_FOREACH(to_c, &to->children, next) { if (to_c == c) { break; } } if (to_c) { return false; } } return true; } void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, Error **errp) { BdrvChild *c, *next; GSList *list = NULL, *p; uint64_t old_perm, old_shared; uint64_t perm = 0, shared = BLK_PERM_ALL; int ret; assert(!atomic_read(&from->in_flight)); assert(!atomic_read(&to->in_flight)); /* Make sure that @from doesn't go away until we have successfully attached * all of its parents to @to. */ bdrv_ref(from); /* Put all parents into @list and calculate their cumulative permissions */ QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) { if (!should_update_child(c, to)) { continue; } list = g_slist_prepend(list, c); perm |= c->perm; shared &= c->shared_perm; } /* Check whether the required permissions can be granted on @to, ignoring * all BdrvChild in @list so that they can't block themselves. */ ret = bdrv_check_update_perm(to, NULL, perm, shared, list, errp); if (ret < 0) { bdrv_abort_perm_update(to); goto out; } /* Now actually perform the change. We performed the permission check for * all elements of @list at once, so set the permissions all at once at the * very end. */ for (p = list; p != NULL; p = p->next) { c = p->data; bdrv_ref(to); bdrv_replace_child_noperm(c, to); bdrv_unref(from); } bdrv_get_cumulative_perm(to, &old_perm, &old_shared); bdrv_set_perm(to, old_perm | perm, old_shared | shared); out: g_slist_free(list); bdrv_unref(from); } /* * 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, Error **errp) { Error *local_err = NULL; bdrv_set_backing_hd(bs_new, bs_top, &local_err); if (local_err) { error_propagate(errp, local_err); goto out; } bdrv_replace_node(bs_top, bs_new, &local_err); if (local_err) { error_propagate(errp, local_err); bdrv_set_backing_hd(bs_new, NULL, &error_abort); goto out; } /* bs_new is now referenced by its new parents, we don't need the * additional reference any more. */ out: bdrv_unref(bs_new); } 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 */ if (bs->node_name[0] != '\0') { QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list); } 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); } /* * 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; if (!drv) { return -ENOMEDIUM; } /* 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 *top, BlockDriverState *base, const char *backing_file_str) { BdrvChild *c, *next; Error *local_err = NULL; int ret = -EIO; bdrv_ref(top); if (!top->drv || !base->drv) { 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 */ /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once * we've figured out how they should work. */ backing_file_str = backing_file_str ? backing_file_str : base->filename; QLIST_FOREACH_SAFE(c, &top->parents, next_parent, next) { /* Check whether we are allowed to switch c from top to base */ GSList *ignore_children = g_slist_prepend(NULL, c); bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm, ignore_children, &local_err); if (local_err) { ret = -EPERM; error_report_err(local_err); goto exit; } g_slist_free(ignore_children); /* If so, update the backing file path in the image file */ if (c->role->update_filename) { ret = c->role->update_filename(c, base, backing_file_str, &local_err); if (ret < 0) { bdrv_abort_perm_update(base); error_report_err(local_err); goto exit; } } /* Do the actual switch in the in-memory graph. * Completes bdrv_check_update_perm() transaction internally. */ bdrv_ref(base); bdrv_replace_child(c, base); bdrv_unref(top); } ret = 0; exit: bdrv_unref(top); return ret; } /** * Truncate file to 'offset' bytes (needed only for file protocols) */ int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc, Error **errp) { BlockDriverState *bs = child->bs; BlockDriver *drv = bs->drv; int ret; assert(child->perm & BLK_PERM_RESIZE); /* if bs->drv == NULL, bs is closed, so there's nothing to do here */ if (!drv) { error_setg(errp, "No medium inserted"); return -ENOMEDIUM; } if (!drv->bdrv_truncate) { if (bs->file && drv->is_filter) { return bdrv_truncate(bs->file, offset, prealloc, errp); } error_setg(errp, "Image format driver does not support resize"); return -ENOTSUP; } if (bs->read_only) { error_setg(errp, "Image is read-only"); return -EACCES; } assert(!(bs->open_flags & BDRV_O_INACTIVE)); ret = drv->bdrv_truncate(bs, offset, prealloc, errp); if (ret < 0) { return ret; } ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); if (ret < 0) { error_setg_errno(errp, -ret, "Could not refresh total sector count"); } else { offset = bs->total_sectors * BDRV_SECTOR_SIZE; } bdrv_dirty_bitmap_truncate(bs, offset); bdrv_parent_cb_resize(bs); atomic_inc(&bs->write_gen); 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; } /* * bdrv_measure: * @drv: Format driver * @opts: Creation options for new image * @in_bs: Existing image containing data for new image (may be NULL) * @errp: Error object * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo()) * or NULL on error * * Calculate file size required to create a new image. * * If @in_bs is given then space for allocated clusters and zero clusters * from that image are included in the calculation. If @opts contains a * backing file that is shared by @in_bs then backing clusters may be omitted * from the calculation. * * If @in_bs is NULL then the calculation includes no allocated clusters * unless a preallocation option is given in @opts. * * Note that @in_bs may use a different BlockDriver from @drv. * * If an error occurs the @errp pointer is set. */ BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts, BlockDriverState *in_bs, Error **errp) { if (!drv->bdrv_measure) { error_setg(errp, "Block driver '%s' does not support size measurement", drv->format_name); return NULL; } return drv->bdrv_measure(opts, in_bs, errp); } /** * 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; } bool bdrv_is_sg(BlockDriverState *bs) { return bs->sg; } bool bdrv_is_encrypted(BlockDriverState *bs) { if (bs->backing && bs->backing->bs->encrypted) { return true; } return bs->encrypted; } 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(*(char *const *)a, *(char *const *)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; } } } for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); i++) { const char *format_name = block_driver_modules[i].format_name; if (format_name) { bool found = false; int j = count; while (formats && j && !found) { found = !strcmp(formats[--j], format_name); } if (!found) { formats = g_renew(const char *, formats, count + 1); formats[count++] = 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(NULL, 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); } const char *bdrv_get_node_name(const BlockDriverState *bs) { return bs->node_name; } const char *bdrv_get_parent_name(const BlockDriverState *bs) { BdrvChild *c; const char *name; /* If multiple parents have a name, just pick the first one. */ QLIST_FOREACH(c, &bs->parents, next_parent) { if (c->role->get_name) { name = c->role->get_name(c); if (name && *name) { return name; } } } return NULL; } /* TODO check what callers really want: bs->node_name or blk_name() */ const char *bdrv_get_device_name(const BlockDriverState *bs) { return bdrv_get_parent_name(bs) ?: ""; } /* 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 bdrv_get_parent_name(bs) ?: 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) { if (!bs->drv) { return 0; } /* 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); } if (bs->file && bs->drv->is_filter) { return bdrv_has_zero_init(bs->file->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) { if (!(bs->open_flags & BDRV_O_UNMAP)) { return false; } return bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP; } 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 bs->drv == NULL, bs is closed, so there's nothing to do here */ if (!drv) { return -ENOMEDIUM; } if (!drv->bdrv_get_info) { if (bs->file && drv->is_filter) { return bdrv_get_info(bs->file->bs, bdi); } 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; } /* 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; Error *local_error = 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; } /* Also check against the full backing filename for the image */ bdrv_get_full_backing_filename(curr_bs, backing_file_full, PATH_MAX, &local_error); if (local_error == NULL) { if (strcmp(backing_file, backing_file_full) == 0) { retval = curr_bs->backing->bs; break; } } else { error_free(local_error); local_error = NULL; } } 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; } 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) { BdrvChild *child, *parent; uint64_t perm, shared_perm; Error *local_err = NULL; int ret; if (!bs->drv) { return; } if (!(bs->open_flags & BDRV_O_INACTIVE)) { return; } QLIST_FOREACH(child, &bs->children, next) { bdrv_invalidate_cache(child->bs, &local_err); if (local_err) { error_propagate(errp, local_err); return; } } /* * Update permissions, they may differ for inactive nodes. * * Note that the required permissions of inactive images are always a * subset of the permissions required after activating the image. This * allows us to just get the permissions upfront without restricting * drv->bdrv_invalidate_cache(). * * It also means that in error cases, we don't have to try and revert to * the old permissions (which is an operation that could fail, too). We can * just keep the extended permissions for the next time that an activation * of the image is tried. */ bs->open_flags &= ~BDRV_O_INACTIVE; bdrv_get_cumulative_perm(bs, &perm, &shared_perm); ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, &local_err); if (ret < 0) { bs->open_flags |= BDRV_O_INACTIVE; error_propagate(errp, local_err); return; } bdrv_set_perm(bs, perm, shared_perm); if (bs->drv->bdrv_invalidate_cache) { bs->drv->bdrv_invalidate_cache(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; } QLIST_FOREACH(parent, &bs->parents, next_parent) { if (parent->role->activate) { parent->role->activate(parent, &local_err); if (local_err) { error_propagate(errp, local_err); return; } } } } void bdrv_invalidate_cache_all(Error **errp) { BlockDriverState *bs; Error *local_err = NULL; BdrvNextIterator it; for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 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); bdrv_next_cleanup(&it); return; } } } static int bdrv_inactivate_recurse(BlockDriverState *bs, bool setting_flag) { BdrvChild *child, *parent; int ret; if (!bs->drv) { return -ENOMEDIUM; } if (!setting_flag && bs->drv->bdrv_inactivate) { ret = bs->drv->bdrv_inactivate(bs); if (ret < 0) { return ret; } } if (setting_flag && !(bs->open_flags & BDRV_O_INACTIVE)) { uint64_t perm, shared_perm; QLIST_FOREACH(parent, &bs->parents, next_parent) { if (parent->role->inactivate) { ret = parent->role->inactivate(parent); if (ret < 0) { return ret; } } } bs->open_flags |= BDRV_O_INACTIVE; /* Update permissions, they may differ for inactive nodes */ bdrv_get_cumulative_perm(bs, &perm, &shared_perm); bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, &error_abort); bdrv_set_perm(bs, perm, shared_perm); } QLIST_FOREACH(child, &bs->children, next) { ret = bdrv_inactivate_recurse(child->bs, setting_flag); if (ret < 0) { return ret; } } /* At this point persistent bitmaps should be already stored by the format * driver */ bdrv_release_persistent_dirty_bitmaps(bs); return 0; } int bdrv_inactivate_all(void) { BlockDriverState *bs = NULL; BdrvNextIterator it; int ret = 0; int pass; GSList *aio_ctxs = NULL, *ctx; for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { AioContext *aio_context = bdrv_get_aio_context(bs); if (!g_slist_find(aio_ctxs, aio_context)) { aio_ctxs = g_slist_prepend(aio_ctxs, aio_context); aio_context_acquire(aio_context); } } /* We do two passes of inactivation. The first pass calls to drivers' * .bdrv_inactivate callbacks recursively so all cache is flushed to disk; * the second pass sets the BDRV_O_INACTIVE flag so that no further write * is allowed. */ for (pass = 0; pass < 2; pass++) { for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { ret = bdrv_inactivate_recurse(bs, pass); if (ret < 0) { bdrv_next_cleanup(&it); goto out; } } } out: for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) { AioContext *aio_context = ctx->data; aio_context_release(aio_context); } g_slist_free(aio_ctxs); return ret; } /**************************************************************/ /* 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; } /** * If eject_flag is TRUE, eject the media. Otherwise, close the tray */ void bdrv_eject(BlockDriverState *bs, bool eject_flag) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_eject) { drv->bdrv_eject(bs, eject_flag); } } /** * 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]); error_propagate(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, bool quiet, Error **errp) { 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, unless we have a backing * file and we have not been forbidden from opening it. */ size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size); if (backing_file && !(flags & BDRV_O_NO_BACKING)) { BlockDriverState *bs; char *full_backing = g_new0(char, PATH_MAX); 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; back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); backing_options = qdict_new(); if (backing_fmt) { qdict_put_str(backing_options, "driver", backing_fmt); } qdict_put_bool(backing_options, BDRV_OPT_FORCE_SHARE, true); bs = bdrv_open(full_backing, NULL, backing_options, back_flags, &local_err); g_free(full_backing); if (!bs && size != -1) { /* Couldn't open BS, but we have a size, so it's nonfatal */ warn_reportf_err(local_err, "Could not verify backing image. " "This may become an error in future versions.\n"); local_err = NULL; } else if (!bs) { /* Couldn't open bs, do not have size */ error_append_hint(&local_err, "Could not open backing image to determine size.\n"); goto out; } else { if (size == -1) { /* Opened BS, have no size */ 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); } } /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */ if (size == -1) { 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); error_propagate(errp, local_err); } AioContext *bdrv_get_aio_context(BlockDriverState *bs) { return bs ? bs->aio_context : qemu_get_aio_context(); } AioWait *bdrv_get_aio_wait(BlockDriverState *bs) { return bs ? &bs->wait : NULL; } void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co) { aio_co_enter(bdrv_get_aio_context(bs), co); } static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban) { QLIST_REMOVE(ban, list); g_free(ban); } void bdrv_detach_aio_context(BlockDriverState *bs) { BdrvAioNotifier *baf, *baf_tmp; BdrvChild *child; if (!bs->drv) { return; } assert(!bs->walking_aio_notifiers); bs->walking_aio_notifiers = true; QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) { if (baf->deleted) { bdrv_do_remove_aio_context_notifier(baf); } else { baf->detach_aio_context(baf->opaque); } } /* Never mind iterating again to check for ->deleted. bdrv_close() will * remove remaining aio notifiers if we aren't called again. */ bs->walking_aio_notifiers = false; if (bs->drv->bdrv_detach_aio_context) { bs->drv->bdrv_detach_aio_context(bs); } QLIST_FOREACH(child, &bs->children, next) { bdrv_detach_aio_context(child->bs); } bs->aio_context = NULL; } void bdrv_attach_aio_context(BlockDriverState *bs, AioContext *new_context) { BdrvAioNotifier *ban, *ban_tmp; BdrvChild *child; if (!bs->drv) { return; } bs->aio_context = new_context; QLIST_FOREACH(child, &bs->children, next) { bdrv_attach_aio_context(child->bs, new_context); } if (bs->drv->bdrv_attach_aio_context) { bs->drv->bdrv_attach_aio_context(bs, new_context); } assert(!bs->walking_aio_notifiers); bs->walking_aio_notifiers = true; QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) { if (ban->deleted) { bdrv_do_remove_aio_context_notifier(ban); } else { ban->attached_aio_context(new_context, ban->opaque); } } bs->walking_aio_notifiers = false; } void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) { AioContext *ctx = bdrv_get_aio_context(bs); aio_disable_external(ctx); bdrv_parent_drained_begin(bs, NULL); bdrv_drain(bs); /* ensure there are no in-flight requests */ while (aio_poll(ctx, false)) { /* wait for all bottom halves to execute */ } 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); bdrv_parent_drained_end(bs, NULL); aio_enable_external(ctx); 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 && ban->deleted == false) { if (bs->walking_aio_notifiers) { ban->deleted = true; } else { bdrv_do_remove_aio_context_notifier(ban); } return; } } abort(); } int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts, BlockDriverAmendStatusCB *status_cb, void *cb_opaque) { if (!bs->drv) { return -ENOMEDIUM; } 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; BdrvNextIterator it; /* walk down the bs forest recursively */ for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 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) { bdrv_next_cleanup(&it); 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_str(opts, "driver", drv->format_name); QINCREF(bs->file->bs->full_open_options); qdict_put(opts, "file", 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_str(opts, "driver", 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_str(opts, "filename", 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); } } /* * Hot add/remove a BDS's child. So the user can take a child offline when * it is broken and take a new child online */ void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs, Error **errp) { if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) { error_setg(errp, "The node %s does not support adding a child", bdrv_get_device_or_node_name(parent_bs)); return; } if (!QLIST_EMPTY(&child_bs->parents)) { error_setg(errp, "The node %s already has a parent", child_bs->node_name); return; } parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp); } void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp) { BdrvChild *tmp; if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) { error_setg(errp, "The node %s does not support removing a child", bdrv_get_device_or_node_name(parent_bs)); return; } QLIST_FOREACH(tmp, &parent_bs->children, next) { if (tmp == child) { break; } } if (!tmp) { error_setg(errp, "The node %s does not have a child named %s", bdrv_get_device_or_node_name(parent_bs), bdrv_get_device_or_node_name(child->bs)); return; } parent_bs->drv->bdrv_del_child(parent_bs, child, errp); } bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, uint32_t granularity, Error **errp) { BlockDriver *drv = bs->drv; if (!drv) { error_setg_errno(errp, ENOMEDIUM, "Can't store persistent bitmaps to %s", bdrv_get_device_or_node_name(bs)); return false; } if (!drv->bdrv_can_store_new_dirty_bitmap) { error_setg_errno(errp, ENOTSUP, "Can't store persistent bitmaps to %s", bdrv_get_device_or_node_name(bs)); return false; } return drv->bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp); }