/* * 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 "config-host.h" #include "qemu-common.h" #include "trace.h" #include "monitor/monitor.h" #include "block/block_int.h" #include "block/blockjob.h" #include "qemu/module.h" #include "qapi/qmp/qjson.h" #include "sysemu/sysemu.h" #include "qemu/notify.h" #include "block/coroutine.h" #include "block/qapi.h" #include "qmp-commands.h" #include "qemu/timer.h" #ifdef CONFIG_BSD #include #include #include #include #ifndef __DragonFly__ #include #endif #endif #ifdef _WIN32 #include #endif struct BdrvDirtyBitmap { HBitmap *bitmap; QLIST_ENTRY(BdrvDirtyBitmap) list; }; #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load); static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque); static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque); static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *iov); static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *iov); static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs, int64_t offset, unsigned int bytes, QEMUIOVector *qiov, BdrvRequestFlags flags); static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs, int64_t offset, unsigned int bytes, QEMUIOVector *qiov, BdrvRequestFlags flags); static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BdrvRequestFlags flags, BlockDriverCompletionFunc *cb, void *opaque, bool is_write); static void coroutine_fn bdrv_co_do_rw(void *opaque); static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, int64_t sector_num, int nb_sectors, BdrvRequestFlags flags); static QTAILQ_HEAD(, BlockDriverState) bdrv_states = QTAILQ_HEAD_INITIALIZER(bdrv_states); static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states = QTAILQ_HEAD_INITIALIZER(graph_bdrv_states); static QLIST_HEAD(, BlockDriver) bdrv_drivers = QLIST_HEAD_INITIALIZER(bdrv_drivers); /* 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 /* throttling disk I/O limits */ void bdrv_set_io_limits(BlockDriverState *bs, ThrottleConfig *cfg) { int i; throttle_config(&bs->throttle_state, cfg); for (i = 0; i < 2; i++) { qemu_co_enter_next(&bs->throttled_reqs[i]); } } /* this function drain all the throttled IOs */ static bool bdrv_start_throttled_reqs(BlockDriverState *bs) { bool drained = false; bool enabled = bs->io_limits_enabled; int i; bs->io_limits_enabled = false; for (i = 0; i < 2; i++) { while (qemu_co_enter_next(&bs->throttled_reqs[i])) { drained = true; } } bs->io_limits_enabled = enabled; return drained; } void bdrv_io_limits_disable(BlockDriverState *bs) { bs->io_limits_enabled = false; bdrv_start_throttled_reqs(bs); throttle_destroy(&bs->throttle_state); } static void bdrv_throttle_read_timer_cb(void *opaque) { BlockDriverState *bs = opaque; qemu_co_enter_next(&bs->throttled_reqs[0]); } static void bdrv_throttle_write_timer_cb(void *opaque) { BlockDriverState *bs = opaque; qemu_co_enter_next(&bs->throttled_reqs[1]); } /* should be called before bdrv_set_io_limits if a limit is set */ void bdrv_io_limits_enable(BlockDriverState *bs) { assert(!bs->io_limits_enabled); throttle_init(&bs->throttle_state, QEMU_CLOCK_VIRTUAL, bdrv_throttle_read_timer_cb, bdrv_throttle_write_timer_cb, bs); bs->io_limits_enabled = true; } /* This function makes an IO wait if needed * * @nb_sectors: the number of sectors of the IO * @is_write: is the IO a write */ static void bdrv_io_limits_intercept(BlockDriverState *bs, unsigned int bytes, bool is_write) { /* does this io must wait */ bool must_wait = throttle_schedule_timer(&bs->throttle_state, is_write); /* if must wait or any request of this type throttled queue the IO */ if (must_wait || !qemu_co_queue_empty(&bs->throttled_reqs[is_write])) { qemu_co_queue_wait(&bs->throttled_reqs[is_write]); } /* the IO will be executed, do the accounting */ throttle_account(&bs->throttle_state, is_write, bytes); /* if the next request must wait -> do nothing */ if (throttle_schedule_timer(&bs->throttle_state, is_write)) { return; } /* else queue next request for execution */ qemu_co_queue_next(&bs->throttled_reqs[is_write]); } size_t bdrv_opt_mem_align(BlockDriverState *bs) { if (!bs || !bs->drv) { /* 4k should be on the safe side */ return 4096; } return bs->bl.opt_mem_alignment; } /* check if the path starts with ":" */ static int path_has_protocol(const char *path) { const char *p; #ifdef _WIN32 if (is_windows_drive(path) || is_windows_drive_prefix(path)) { return 0; } p = path + strcspn(path, ":/\\"); #else p = path + strcspn(path, ":/"); #endif return *p == ':'; } int path_is_absolute(const char *path) { #ifdef _WIN32 /* specific case for names like: "\\.\d:" */ if (is_windows_drive(path) || is_windows_drive_prefix(path)) { return 1; } return (*path == '/' || *path == '\\'); #else return (*path == '/'); #endif } /* if filename is absolute, just copy it to dest. Otherwise, build a path to it by considering it is relative to base_path. URL are supported. */ void path_combine(char *dest, int dest_size, const char *base_path, const char *filename) { const char *p, *p1; int len; if (dest_size <= 0) return; if (path_is_absolute(filename)) { pstrcpy(dest, dest_size, filename); } else { p = strchr(base_path, ':'); if (p) p++; else p = base_path; p1 = strrchr(base_path, '/'); #ifdef _WIN32 { const char *p2; p2 = strrchr(base_path, '\\'); if (!p1 || p2 > p1) p1 = p2; } #endif if (p1) p1++; else p1 = base_path; if (p1 > p) p = p1; len = p - base_path; if (len > dest_size - 1) len = dest_size - 1; memcpy(dest, base_path, len); dest[len] = '\0'; pstrcat(dest, dest_size, filename); } } void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz) { if (bs->backing_file[0] == '\0' || path_has_protocol(bs->backing_file)) { pstrcpy(dest, sz, bs->backing_file); } else { path_combine(dest, sz, bs->filename, bs->backing_file); } } void bdrv_register(BlockDriver *bdrv) { /* Block drivers without coroutine functions need emulation */ if (!bdrv->bdrv_co_readv) { bdrv->bdrv_co_readv = bdrv_co_readv_em; bdrv->bdrv_co_writev = bdrv_co_writev_em; /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if * the block driver lacks aio we need to emulate that too. */ if (!bdrv->bdrv_aio_readv) { /* add AIO emulation layer */ bdrv->bdrv_aio_readv = bdrv_aio_readv_em; bdrv->bdrv_aio_writev = bdrv_aio_writev_em; } } QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list); } /* create a new block device (by default it is empty) */ BlockDriverState *bdrv_new(const char *device_name) { BlockDriverState *bs; bs = g_malloc0(sizeof(BlockDriverState)); QLIST_INIT(&bs->dirty_bitmaps); pstrcpy(bs->device_name, sizeof(bs->device_name), device_name); if (device_name[0] != '\0') { QTAILQ_INSERT_TAIL(&bdrv_states, bs, device_list); } bdrv_iostatus_disable(bs); notifier_list_init(&bs->close_notifiers); notifier_with_return_list_init(&bs->before_write_notifiers); qemu_co_queue_init(&bs->throttled_reqs[0]); qemu_co_queue_init(&bs->throttled_reqs[1]); bs->refcnt = 1; return bs; } void bdrv_add_close_notifier(BlockDriverState *bs, Notifier *notify) { notifier_list_add(&bs->close_notifiers, notify); } BlockDriver *bdrv_find_format(const char *format_name) { BlockDriver *drv1; QLIST_FOREACH(drv1, &bdrv_drivers, list) { if (!strcmp(drv1->format_name, format_name)) { return drv1; } } return NULL; } static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only) { static const char *whitelist_rw[] = { CONFIG_BDRV_RW_WHITELIST }; static const char *whitelist_ro[] = { CONFIG_BDRV_RO_WHITELIST }; const char **p; if (!whitelist_rw[0] && !whitelist_ro[0]) { return 1; /* no whitelist, anything goes */ } for (p = whitelist_rw; *p; p++) { if (!strcmp(drv->format_name, *p)) { return 1; } } if (read_only) { for (p = whitelist_ro; *p; p++) { if (!strcmp(drv->format_name, *p)) { return 1; } } } return 0; } BlockDriver *bdrv_find_whitelisted_format(const char *format_name, bool read_only) { BlockDriver *drv = bdrv_find_format(format_name); return drv && bdrv_is_whitelisted(drv, read_only) ? drv : NULL; } typedef struct CreateCo { BlockDriver *drv; char *filename; QEMUOptionParameter *options; int ret; Error *err; } CreateCo; static void coroutine_fn bdrv_create_co_entry(void *opaque) { Error *local_err = NULL; int ret; CreateCo *cco = opaque; assert(cco->drv); ret = cco->drv->bdrv_create(cco->filename, cco->options, &local_err); if (local_err) { error_propagate(&cco->err, local_err); } cco->ret = ret; } int bdrv_create(BlockDriver *drv, const char* filename, QEMUOptionParameter *options, Error **errp) { int ret; Coroutine *co; CreateCo cco = { .drv = drv, .filename = g_strdup(filename), .options = options, .ret = NOT_DONE, .err = NULL, }; if (!drv->bdrv_create) { error_setg(errp, "Driver '%s' does not support image creation", drv->format_name); ret = -ENOTSUP; goto out; } if (qemu_in_coroutine()) { /* Fast-path if already in coroutine context */ bdrv_create_co_entry(&cco); } else { co = qemu_coroutine_create(bdrv_create_co_entry); qemu_coroutine_enter(co, &cco); while (cco.ret == NOT_DONE) { qemu_aio_wait(); } } 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, QEMUOptionParameter *options, Error **errp) { BlockDriver *drv; Error *local_err = NULL; int ret; drv = bdrv_find_protocol(filename, true); if (drv == NULL) { error_setg(errp, "Could not find protocol for file '%s'", filename); return -ENOENT; } ret = bdrv_create(drv, filename, options, &local_err); if (local_err) { error_propagate(errp, local_err); } return ret; } int bdrv_refresh_limits(BlockDriverState *bs) { BlockDriver *drv = bs->drv; memset(&bs->bl, 0, sizeof(bs->bl)); if (!drv) { return 0; } /* Take some limits from the children as a default */ if (bs->file) { bdrv_refresh_limits(bs->file); bs->bl.opt_transfer_length = bs->file->bl.opt_transfer_length; bs->bl.opt_mem_alignment = bs->file->bl.opt_mem_alignment; } else { bs->bl.opt_mem_alignment = 512; } if (bs->backing_hd) { bdrv_refresh_limits(bs->backing_hd); bs->bl.opt_transfer_length = MAX(bs->bl.opt_transfer_length, bs->backing_hd->bl.opt_transfer_length); bs->bl.opt_mem_alignment = MAX(bs->bl.opt_mem_alignment, bs->backing_hd->bl.opt_mem_alignment); } /* Then let the driver override it */ if (drv->bdrv_refresh_limits) { return drv->bdrv_refresh_limits(bs); } return 0; } /* * Create a uniquely-named empty temporary file. * Return 0 upon success, otherwise a negative errno value. */ int get_tmp_filename(char *filename, int size) { #ifdef _WIN32 char temp_dir[MAX_PATH]; /* GetTempFileName requires that its output buffer (4th param) have length MAX_PATH or greater. */ assert(size >= MAX_PATH); return (GetTempPath(MAX_PATH, temp_dir) && GetTempFileName(temp_dir, "qem", 0, filename) ? 0 : -GetLastError()); #else int fd; const char *tmpdir; tmpdir = getenv("TMPDIR"); if (!tmpdir) { tmpdir = "/var/tmp"; } if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) { return -EOVERFLOW; } fd = mkstemp(filename); if (fd < 0) { return -errno; } if (close(fd) != 0) { unlink(filename); return -errno; } return 0; #endif } /* * Detect host devices. By convention, /dev/cdrom[N] is always * recognized as a host CDROM. */ static BlockDriver *find_hdev_driver(const char *filename) { int score_max = 0, score; BlockDriver *drv = NULL, *d; QLIST_FOREACH(d, &bdrv_drivers, list) { if (d->bdrv_probe_device) { score = d->bdrv_probe_device(filename); if (score > score_max) { score_max = score; drv = d; } } } return drv; } BlockDriver *bdrv_find_protocol(const char *filename, bool allow_protocol_prefix) { BlockDriver *drv1; char protocol[128]; int len; const char *p; /* TODO Drivers without bdrv_file_open must be specified explicitly */ /* * XXX(hch): we really should not let host device detection * override an explicit protocol specification, but moving this * later breaks access to device names with colons in them. * Thanks to the brain-dead persistent naming schemes on udev- * based Linux systems those actually are quite common. */ drv1 = find_hdev_driver(filename); if (drv1) { return drv1; } if (!path_has_protocol(filename) || !allow_protocol_prefix) { return bdrv_find_format("file"); } p = strchr(filename, ':'); assert(p != NULL); len = p - filename; if (len > sizeof(protocol) - 1) len = sizeof(protocol) - 1; memcpy(protocol, filename, len); protocol[len] = '\0'; QLIST_FOREACH(drv1, &bdrv_drivers, list) { if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) { return drv1; } } return NULL; } static int find_image_format(BlockDriverState *bs, const char *filename, BlockDriver **pdrv, Error **errp) { int score, score_max; BlockDriver *drv1, *drv; uint8_t buf[2048]; int ret = 0; /* Return the raw BlockDriver * to scsi-generic devices or empty drives */ if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) { drv = bdrv_find_format("raw"); if (!drv) { error_setg(errp, "Could not find raw image format"); ret = -ENOENT; } *pdrv = drv; return ret; } ret = bdrv_pread(bs, 0, buf, sizeof(buf)); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read image for determining its " "format"); *pdrv = NULL; return ret; } score_max = 0; drv = NULL; QLIST_FOREACH(drv1, &bdrv_drivers, list) { if (drv1->bdrv_probe) { score = drv1->bdrv_probe(buf, ret, filename); if (score > score_max) { score_max = score; drv = drv1; } } } 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 */ static int refresh_total_sectors(BlockDriverState *bs, int64_t hint) { BlockDriver *drv = bs->drv; /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */ if (bs->sg) 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; } /** * Set open flags for a given discard mode * * Return 0 on success, -1 if the discard mode was invalid. */ int bdrv_parse_discard_flags(const char *mode, int *flags) { *flags &= ~BDRV_O_UNMAP; if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) { /* do nothing */ } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) { *flags |= BDRV_O_UNMAP; } else { return -1; } return 0; } /** * Set open flags for a given cache mode * * Return 0 on success, -1 if the cache mode was invalid. */ int bdrv_parse_cache_flags(const char *mode, int *flags) { *flags &= ~BDRV_O_CACHE_MASK; if (!strcmp(mode, "off") || !strcmp(mode, "none")) { *flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; } else if (!strcmp(mode, "directsync")) { *flags |= BDRV_O_NOCACHE; } else if (!strcmp(mode, "writeback")) { *flags |= BDRV_O_CACHE_WB; } else if (!strcmp(mode, "unsafe")) { *flags |= BDRV_O_CACHE_WB; *flags |= BDRV_O_NO_FLUSH; } else if (!strcmp(mode, "writethrough")) { /* this is the default */ } else { return -1; } return 0; } /** * The copy-on-read flag is actually a reference count so multiple users may * use the feature without worrying about clobbering its previous state. * Copy-on-read stays enabled until all users have called to disable it. */ void bdrv_enable_copy_on_read(BlockDriverState *bs) { bs->copy_on_read++; } void bdrv_disable_copy_on_read(BlockDriverState *bs) { assert(bs->copy_on_read > 0); bs->copy_on_read--; } static int bdrv_open_flags(BlockDriverState *bs, int flags) { int open_flags = flags | BDRV_O_CACHE_WB; /* The backing file of a temporary snapshot is read-only */ if (flags & BDRV_O_SNAPSHOT) { open_flags &= ~BDRV_O_RDWR; } /* * Clear flags that are internal to the block layer before opening the * image. */ open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); /* * Snapshots should be writable. */ if (bs->is_temporary) { open_flags |= BDRV_O_RDWR; } return open_flags; } static int bdrv_assign_node_name(BlockDriverState *bs, const char *node_name, Error **errp) { if (!node_name) { return 0; } /* empty string node name is invalid */ if (node_name[0] == '\0') { error_setg(errp, "Empty node name"); return -EINVAL; } /* takes care of avoiding namespaces collisions */ if (bdrv_find(node_name)) { error_setg(errp, "node-name=%s is conflicting with a device id", node_name); return -EINVAL; } /* takes care of avoiding duplicates node names */ if (bdrv_find_node(node_name)) { error_setg(errp, "Duplicate node name"); return -EINVAL; } /* 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); return 0; } /* * Common part for opening disk images and files * * Removes all processed options from *options. */ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file, QDict *options, int flags, BlockDriver *drv, Error **errp) { int ret, open_flags; const char *filename; const char *node_name = NULL; Error *local_err = NULL; assert(drv != NULL); assert(bs->file == NULL); assert(options != NULL && bs->options != options); if (file != NULL) { filename = file->filename; } else { filename = qdict_get_try_str(options, "filename"); } if (drv->bdrv_needs_filename && !filename) { error_setg(errp, "The '%s' block driver requires a file name", drv->format_name); return -EINVAL; } trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name); node_name = qdict_get_try_str(options, "node-name"); ret = bdrv_assign_node_name(bs, node_name, errp); if (ret < 0) { return ret; } qdict_del(options, "node-name"); /* bdrv_open() with directly using a protocol as drv. This layer is already * opened, so assign it to bs (while file becomes a closed BlockDriverState) * and return immediately. */ if (file != NULL && drv->bdrv_file_open) { bdrv_swap(file, bs); return 0; } bs->open_flags = flags; bs->guest_block_size = 512; bs->request_alignment = 512; bs->zero_beyond_eof = true; open_flags = bdrv_open_flags(bs, flags); bs->read_only = !(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); return -ENOTSUP; } assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */ if (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"); return -EINVAL; } } if (filename != NULL) { pstrcpy(bs->filename, sizeof(bs->filename), filename); } else { bs->filename[0] = '\0'; } bs->drv = drv; bs->opaque = g_malloc0(drv->instance_size); bs->enable_write_cache = !!(flags & BDRV_O_CACHE_WB); /* Open the image, either directly or using a protocol */ if (drv->bdrv_file_open) { assert(file == NULL); assert(!drv->bdrv_needs_filename || filename != NULL); ret = drv->bdrv_file_open(bs, options, open_flags, &local_err); } else { if (file == NULL) { error_setg(errp, "Can't use '%s' as a block driver for the " "protocol level", drv->format_name); ret = -EINVAL; goto free_and_fail; } bs->file = file; ret = drv->bdrv_open(bs, options, open_flags, &local_err); } if (ret < 0) { if (local_err) { error_propagate(errp, local_err); } else if (bs->filename[0]) { error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename); } else { error_setg_errno(errp, -ret, "Could not open image"); } goto free_and_fail; } ret = refresh_total_sectors(bs, bs->total_sectors); if (ret < 0) { error_setg_errno(errp, -ret, "Could not refresh total sector count"); goto free_and_fail; } bdrv_refresh_limits(bs); assert(bdrv_opt_mem_align(bs) != 0); assert((bs->request_alignment != 0) || bs->sg); #ifndef _WIN32 if (bs->is_temporary) { assert(bs->filename[0] != '\0'); unlink(bs->filename); } #endif return 0; free_and_fail: bs->file = NULL; g_free(bs->opaque); bs->opaque = NULL; bs->drv = NULL; return ret; } /* * Opens a file using a protocol (file, host_device, nbd, ...) * * options is an indirect pointer to a QDict of options to pass to the block * drivers, or pointer to NULL for an empty set of options. If this function * takes ownership of the QDict reference, it will set *options to NULL; * otherwise, it will contain unused/unrecognized options after this function * returns. Then, the caller is responsible for freeing it. If it intends to * reuse the QDict, QINCREF() should be called beforehand. */ static int bdrv_file_open(BlockDriverState *bs, const char *filename, QDict **options, int flags, Error **errp) { BlockDriver *drv; const char *drvname; bool parse_filename = false; Error *local_err = NULL; int ret; /* Fetch the file name from the options QDict if necessary */ if (!filename) { filename = qdict_get_try_str(*options, "filename"); } else if (filename && !qdict_haskey(*options, "filename")) { qdict_put(*options, "filename", qstring_from_str(filename)); parse_filename = true; } else { error_setg(errp, "Can't specify 'file' and 'filename' options at the " "same time"); ret = -EINVAL; goto fail; } /* Find the right block driver */ drvname = qdict_get_try_str(*options, "driver"); if (drvname) { drv = bdrv_find_format(drvname); if (!drv) { error_setg(errp, "Unknown driver '%s'", drvname); } qdict_del(*options, "driver"); } else if (filename) { drv = bdrv_find_protocol(filename, parse_filename); if (!drv) { error_setg(errp, "Unknown protocol"); } } else { error_setg(errp, "Must specify either driver or file"); drv = NULL; } if (!drv) { /* errp has been set already */ ret = -ENOENT; goto fail; } /* Parse the filename and open it */ if (drv->bdrv_parse_filename && parse_filename) { drv->bdrv_parse_filename(filename, *options, &local_err); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto fail; } if (!drv->bdrv_needs_filename) { qdict_del(*options, "filename"); } else { filename = qdict_get_str(*options, "filename"); } } if (!drv->bdrv_file_open) { ret = bdrv_open(&bs, filename, NULL, *options, flags, drv, &local_err); *options = NULL; } else { ret = bdrv_open_common(bs, NULL, *options, flags, drv, &local_err); } if (ret < 0) { error_propagate(errp, local_err); goto fail; } bs->growable = 1; return 0; fail: return ret; } /* * Opens the backing file for a BlockDriverState if not yet open * * 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 is transferred to this * function (even on failure), so if the caller intends to reuse the dictionary, * it needs to use QINCREF() before calling bdrv_file_open. */ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) { char backing_filename[PATH_MAX]; int back_flags, ret; BlockDriver *back_drv = NULL; Error *local_err = NULL; if (bs->backing_hd != NULL) { QDECREF(options); return 0; } /* NULL means an empty set of options */ if (options == NULL) { options = qdict_new(); } bs->open_flags &= ~BDRV_O_NO_BACKING; if (qdict_haskey(options, "file.filename")) { backing_filename[0] = '\0'; } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { QDECREF(options); return 0; } else { bdrv_get_full_backing_filename(bs, backing_filename, sizeof(backing_filename)); } if (bs->backing_format[0] != '\0') { back_drv = bdrv_find_format(bs->backing_format); } /* backing files always opened read-only */ back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_COPY_ON_READ); assert(bs->backing_hd == NULL); ret = bdrv_open(&bs->backing_hd, *backing_filename ? backing_filename : NULL, NULL, options, back_flags, back_drv, &local_err); if (ret < 0) { bs->backing_hd = NULL; bs->open_flags |= BDRV_O_NO_BACKING; error_setg(errp, "Could not open backing file: %s", error_get_pretty(local_err)); error_free(local_err); return ret; } if (bs->backing_hd->file) { pstrcpy(bs->backing_file, sizeof(bs->backing_file), bs->backing_hd->file->filename); } /* Recalculate the BlockLimits with the backing file */ bdrv_refresh_limits(bs); return 0; } /* * 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. *pbs will remain unchanged and 0 will be returned. * * 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. * * To conform with the behavior of bdrv_open(), *pbs has to be NULL. */ int bdrv_open_image(BlockDriverState **pbs, const char *filename, QDict *options, const char *bdref_key, int flags, bool allow_none, Error **errp) { QDict *image_options; int ret; char *bdref_key_dot; const char *reference; assert(pbs); assert(*pbs == NULL); bdref_key_dot = g_strdup_printf("%s.", bdref_key); qdict_extract_subqdict(options, &image_options, bdref_key_dot); g_free(bdref_key_dot); reference = qdict_get_try_str(options, bdref_key); if (!filename && !reference && !qdict_size(image_options)) { if (allow_none) { ret = 0; } else { error_setg(errp, "A block device must be specified for \"%s\"", bdref_key); ret = -EINVAL; } goto done; } ret = bdrv_open(pbs, filename, reference, image_options, flags, NULL, errp); done: qdict_del(options, bdref_key); return ret; } void bdrv_append_temp_snapshot(BlockDriverState *bs, Error **errp) { /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */ char tmp_filename[PATH_MAX + 1]; int64_t total_size; BlockDriver *bdrv_qcow2; QEMUOptionParameter *create_options; QDict *snapshot_options; BlockDriverState *bs_snapshot; Error *local_err; 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"); return; } total_size &= BDRV_SECTOR_MASK; /* Create the temporary image */ ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename)); if (ret < 0) { error_setg_errno(errp, -ret, "Could not get temporary filename"); return; } bdrv_qcow2 = bdrv_find_format("qcow2"); create_options = parse_option_parameters("", bdrv_qcow2->create_options, NULL); set_option_parameter_int(create_options, BLOCK_OPT_SIZE, total_size); ret = bdrv_create(bdrv_qcow2, tmp_filename, create_options, &local_err); free_option_parameters(create_options); if (ret < 0) { error_setg_errno(errp, -ret, "Could not create temporary overlay " "'%s': %s", tmp_filename, error_get_pretty(local_err)); error_free(local_err); return; } /* Prepare a new options QDict for the temporary file */ snapshot_options = qdict_new(); qdict_put(snapshot_options, "file.driver", qstring_from_str("file")); qdict_put(snapshot_options, "file.filename", qstring_from_str(tmp_filename)); bs_snapshot = bdrv_new(""); bs_snapshot->is_temporary = 1; ret = bdrv_open(&bs_snapshot, NULL, NULL, snapshot_options, bs->open_flags & ~BDRV_O_SNAPSHOT, bdrv_qcow2, &local_err); if (ret < 0) { error_propagate(errp, local_err); return; } bdrv_append(bs_snapshot, bs); } /* * 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). */ int bdrv_open(BlockDriverState **pbs, const char *filename, const char *reference, QDict *options, int flags, BlockDriver *drv, Error **errp) { int ret; BlockDriverState *file = NULL, *bs; const char *drvname; Error *local_err = NULL; assert(pbs); if (reference) { bool options_non_empty = options ? qdict_size(options) : false; QDECREF(options); if (*pbs) { error_setg(errp, "Cannot reuse an existing BDS when referencing " "another block device"); return -EINVAL; } if (filename || options_non_empty) { error_setg(errp, "Cannot reference an existing block device with " "additional options or a new filename"); return -EINVAL; } bs = bdrv_lookup_bs(reference, reference, errp); if (!bs) { return -ENODEV; } bdrv_ref(bs); *pbs = bs; return 0; } if (*pbs) { bs = *pbs; } else { bs = bdrv_new(""); } /* NULL means an empty set of options */ if (options == NULL) { options = qdict_new(); } bs->options = options; options = qdict_clone_shallow(options); if (flags & BDRV_O_PROTOCOL) { assert(!drv); ret = bdrv_file_open(bs, filename, &options, flags & ~BDRV_O_PROTOCOL, &local_err); if (!ret) { drv = bs->drv; goto done; } else if (bs->drv) { goto close_and_fail; } else { goto fail; } } /* Open image file without format layer */ if (flags & BDRV_O_RDWR) { flags |= BDRV_O_ALLOW_RDWR; } assert(file == NULL); ret = bdrv_open_image(&file, filename, options, "file", bdrv_open_flags(bs, flags | BDRV_O_UNMAP) | BDRV_O_PROTOCOL, true, &local_err); if (ret < 0) { goto unlink_and_fail; } /* Find the right image format driver */ drvname = qdict_get_try_str(options, "driver"); if (drvname) { drv = bdrv_find_format(drvname); qdict_del(options, "driver"); if (!drv) { error_setg(errp, "Invalid driver: '%s'", drvname); ret = -EINVAL; goto unlink_and_fail; } } if (!drv) { if (file) { ret = find_image_format(file, filename, &drv, &local_err); } else { error_setg(errp, "Must specify either driver or file"); ret = -EINVAL; goto unlink_and_fail; } } if (!drv) { goto unlink_and_fail; } /* Open the image */ ret = bdrv_open_common(bs, file, options, flags, drv, &local_err); if (ret < 0) { goto unlink_and_fail; } if (file && (bs->file != file)) { bdrv_unref(file); file = NULL; } /* If there is a backing file, use it */ if ((flags & BDRV_O_NO_BACKING) == 0) { QDict *backing_options; qdict_extract_subqdict(options, &backing_options, "backing."); ret = bdrv_open_backing_file(bs, backing_options, &local_err); if (ret < 0) { goto close_and_fail; } } /* For snapshot=on, create a temporary qcow2 overlay. bs points to the * temporary snapshot afterwards. */ if (flags & BDRV_O_SNAPSHOT) { bdrv_append_temp_snapshot(bs, &local_err); if (local_err) { error_propagate(errp, local_err); goto close_and_fail; } } done: /* Check if any unknown options were used */ if (options && (qdict_size(options) != 0)) { const QDictEntry *entry = qdict_first(options); if (flags & BDRV_O_PROTOCOL) { error_setg(errp, "Block protocol '%s' doesn't support the option " "'%s'", drv->format_name, entry->key); } else { error_setg(errp, "Block format '%s' used by device '%s' doesn't " "support the option '%s'", drv->format_name, bs->device_name, entry->key); } ret = -EINVAL; goto close_and_fail; } if (!bdrv_key_required(bs)) { bdrv_dev_change_media_cb(bs, true); } else if (!runstate_check(RUN_STATE_PRELAUNCH) && !runstate_check(RUN_STATE_INMIGRATE) && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */ error_setg(errp, "Guest must be stopped for opening of encrypted image"); ret = -EBUSY; goto close_and_fail; } QDECREF(options); *pbs = bs; return 0; unlink_and_fail: if (file != NULL) { bdrv_unref(file); } if (bs->is_temporary) { unlink(filename); } fail: QDECREF(bs->options); QDECREF(options); bs->options = NULL; if (!*pbs) { /* If *pbs is NULL, a new BDS has been created in this function and needs to be freed now. Otherwise, it does not need to be closed, since it has not really been opened yet. */ bdrv_unref(bs); } if (local_err) { error_propagate(errp, local_err); } return ret; close_and_fail: /* See fail path, but now the BDS has to be always closed */ if (*pbs) { bdrv_close(bs); } else { bdrv_unref(bs); } QDECREF(options); if (local_err) { error_propagate(errp, local_err); } return ret; } typedef struct BlockReopenQueueEntry { bool prepared; BDRVReopenState state; QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; } BlockReopenQueueEntry; /* * Adds a BlockDriverState to a simple queue for an atomic, transactional * reopen of multiple devices. * * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT * already performed, or alternatively may be NULL a new BlockReopenQueue will * be created and initialized. This newly created BlockReopenQueue should be * passed back in for subsequent calls that are intended to be of the same * atomic 'set'. * * bs is the BlockDriverState to add to the reopen queue. * * 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. * */ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, BlockDriverState *bs, int flags) { assert(bs != NULL); BlockReopenQueueEntry *bs_entry; if (bs_queue == NULL) { bs_queue = g_new0(BlockReopenQueue, 1); QSIMPLEQ_INIT(bs_queue); } if (bs->file) { bdrv_reopen_queue(bs_queue, bs->file, flags); } bs_entry = g_new0(BlockReopenQueueEntry, 1); QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry); bs_entry->state.bs = bs; bs_entry->state.flags = flags; return bs_queue; } /* * Reopen multiple BlockDriverStates atomically & transactionally. * * The queue passed in (bs_queue) must have been built up previous * via bdrv_reopen_queue(). * * Reopens all BDS specified in the queue, with the appropriate * flags. All devices are prepared for reopen, and failure of any * device will cause all device changes to be abandonded, and intermediate * data cleaned up. * * If all devices prepare successfully, then the changes are committed * to all devices. * */ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) { int ret = -1; BlockReopenQueueEntry *bs_entry, *next; Error *local_err = NULL; assert(bs_queue != NULL); bdrv_drain_all(); QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) { error_propagate(errp, local_err); goto cleanup; } bs_entry->prepared = true; } /* If we reach this point, we have success and just need to apply the * changes */ QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { bdrv_reopen_commit(&bs_entry->state); } ret = 0; cleanup: QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { if (ret && bs_entry->prepared) { bdrv_reopen_abort(&bs_entry->state); } g_free(bs_entry); } g_free(bs_queue); return ret; } /* Reopen a single BlockDriverState with the specified flags. */ int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp) { int ret = -1; Error *local_err = NULL; BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, bdrv_flags); ret = bdrv_reopen_multiple(queue, &local_err); if (local_err != NULL) { error_propagate(errp, local_err); } return ret; } /* * Prepares a BlockDriverState for reopen. All changes are staged in the * 'opaque' field of the BDRVReopenState, which is used and allocated by * the block driver layer .bdrv_reopen_prepare() * * bs is the BlockDriverState to reopen * flags are the new open flags * queue is the reopen queue * * Returns 0 on success, non-zero on error. On error errp will be set * as well. * * On failure, bdrv_reopen_abort() will be called to clean up any data. * It is the responsibility of the caller to then call the abort() or * commit() for any other BDS that have been left in a prepare() state * */ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, Error **errp) { int ret = -1; Error *local_err = NULL; BlockDriver *drv; assert(reopen_state != NULL); assert(reopen_state->bs->drv != NULL); drv = reopen_state->bs->drv; /* if we are to stay read-only, do not allow permission change * to r/w */ if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) && reopen_state->flags & BDRV_O_RDWR) { error_set(errp, QERR_DEVICE_IS_READ_ONLY, reopen_state->bs->device_name); goto error; } ret = bdrv_flush(reopen_state->bs); if (ret) { error_set(errp, ERROR_CLASS_GENERIC_ERROR, "Error (%s) flushing drive", strerror(-ret)); 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_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, drv->format_name, reopen_state->bs->device_name, "reopening of file"); ret = -1; goto error; } ret = 0; error: return ret; } /* * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and * makes them final by swapping the staging BlockDriverState contents into * the active BlockDriverState contents. */ void bdrv_reopen_commit(BDRVReopenState *reopen_state) { BlockDriver *drv; assert(reopen_state != NULL); drv = reopen_state->bs->drv; assert(drv != NULL); /* If there are any driver level actions to take */ if (drv->bdrv_reopen_commit) { drv->bdrv_reopen_commit(reopen_state); } /* set BDS specific flags now */ reopen_state->bs->open_flags = reopen_state->flags; reopen_state->bs->enable_write_cache = !!(reopen_state->flags & BDRV_O_CACHE_WB); reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR); bdrv_refresh_limits(reopen_state->bs); } /* * 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); } } void bdrv_close(BlockDriverState *bs) { if (bs->job) { block_job_cancel_sync(bs->job); } bdrv_drain_all(); /* complete I/O */ bdrv_flush(bs); bdrv_drain_all(); /* in case flush left pending I/O */ notifier_list_notify(&bs->close_notifiers, bs); if (bs->drv) { if (bs->backing_hd) { bdrv_unref(bs->backing_hd); bs->backing_hd = NULL; } bs->drv->bdrv_close(bs); g_free(bs->opaque); #ifdef _WIN32 if (bs->is_temporary) { unlink(bs->filename); } #endif bs->opaque = NULL; bs->drv = NULL; bs->copy_on_read = 0; bs->backing_file[0] = '\0'; bs->backing_format[0] = '\0'; bs->total_sectors = 0; bs->encrypted = 0; bs->valid_key = 0; bs->sg = 0; bs->growable = 0; bs->zero_beyond_eof = false; QDECREF(bs->options); bs->options = NULL; if (bs->file != NULL) { bdrv_unref(bs->file); bs->file = NULL; } } bdrv_dev_change_media_cb(bs, false); /*throttling disk I/O limits*/ if (bs->io_limits_enabled) { bdrv_io_limits_disable(bs); } } void bdrv_close_all(void) { BlockDriverState *bs; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { bdrv_close(bs); } } /* Check if any requests are in-flight (including throttled requests) */ static bool bdrv_requests_pending(BlockDriverState *bs) { if (!QLIST_EMPTY(&bs->tracked_requests)) { return true; } if (!qemu_co_queue_empty(&bs->throttled_reqs[0])) { return true; } if (!qemu_co_queue_empty(&bs->throttled_reqs[1])) { return true; } if (bs->file && bdrv_requests_pending(bs->file)) { return true; } if (bs->backing_hd && bdrv_requests_pending(bs->backing_hd)) { return true; } return false; } static bool bdrv_requests_pending_all(void) { BlockDriverState *bs; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { if (bdrv_requests_pending(bs)) { return true; } } return false; } /* * Wait for pending requests to complete across all BlockDriverStates * * This function does not flush data to disk, use bdrv_flush_all() for that * after calling this function. * * Note that completion of an asynchronous I/O operation can trigger any * number of other I/O operations on other devices---for example a coroutine * can be arbitrarily complex and a constant flow of I/O can come until the * coroutine is complete. Because of this, it is not possible to have a * function to drain a single device's I/O queue. */ void bdrv_drain_all(void) { /* Always run first iteration so any pending completion BHs run */ bool busy = true; BlockDriverState *bs; while (busy) { QTAILQ_FOREACH(bs, &bdrv_states, device_list) { bdrv_start_throttled_reqs(bs); } busy = bdrv_requests_pending_all(); busy |= aio_poll(qemu_get_aio_context(), busy); } } /* make a BlockDriverState anonymous by removing from bdrv_state and * graph_bdrv_state list. Also, NULL terminate the device_name to prevent double remove */ void bdrv_make_anon(BlockDriverState *bs) { if (bs->device_name[0] != '\0') { QTAILQ_REMOVE(&bdrv_states, bs, device_list); } bs->device_name[0] = '\0'; if (bs->node_name[0] != '\0') { QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list); } bs->node_name[0] = '\0'; } static void bdrv_rebind(BlockDriverState *bs) { if (bs->drv && bs->drv->bdrv_rebind) { bs->drv->bdrv_rebind(bs); } } static void bdrv_move_feature_fields(BlockDriverState *bs_dest, BlockDriverState *bs_src) { /* move some fields that need to stay attached to the device */ bs_dest->open_flags = bs_src->open_flags; /* dev info */ bs_dest->dev_ops = bs_src->dev_ops; bs_dest->dev_opaque = bs_src->dev_opaque; bs_dest->dev = bs_src->dev; bs_dest->guest_block_size = bs_src->guest_block_size; bs_dest->copy_on_read = bs_src->copy_on_read; bs_dest->enable_write_cache = bs_src->enable_write_cache; /* i/o throttled req */ memcpy(&bs_dest->throttle_state, &bs_src->throttle_state, sizeof(ThrottleState)); bs_dest->throttled_reqs[0] = bs_src->throttled_reqs[0]; bs_dest->throttled_reqs[1] = bs_src->throttled_reqs[1]; bs_dest->io_limits_enabled = bs_src->io_limits_enabled; /* r/w error */ bs_dest->on_read_error = bs_src->on_read_error; bs_dest->on_write_error = bs_src->on_write_error; /* i/o status */ bs_dest->iostatus_enabled = bs_src->iostatus_enabled; bs_dest->iostatus = bs_src->iostatus; /* dirty bitmap */ bs_dest->dirty_bitmaps = bs_src->dirty_bitmaps; /* reference count */ bs_dest->refcnt = bs_src->refcnt; /* job */ bs_dest->in_use = bs_src->in_use; bs_dest->job = bs_src->job; /* keep the same entry in bdrv_states */ pstrcpy(bs_dest->device_name, sizeof(bs_dest->device_name), bs_src->device_name); bs_dest->device_list = bs_src->device_list; } /* * Swap bs contents for two image chains while they are live, * while keeping required fields on the BlockDriverState that is * actually attached to a device. * * This will modify the BlockDriverState fields, and swap contents * between bs_new and bs_old. Both bs_new and bs_old are modified. * * bs_new is required to be anonymous. * * This function does not create any image files. */ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old) { BlockDriverState tmp; /* The code needs to swap the node_name but simply swapping node_list won't * work so first remove the nodes from the graph list, do the swap then * insert them back if needed. */ if (bs_new->node_name[0] != '\0') { QTAILQ_REMOVE(&graph_bdrv_states, bs_new, node_list); } if (bs_old->node_name[0] != '\0') { QTAILQ_REMOVE(&graph_bdrv_states, bs_old, node_list); } /* bs_new must be anonymous and shouldn't have anything fancy enabled */ assert(bs_new->device_name[0] == '\0'); assert(QLIST_EMPTY(&bs_new->dirty_bitmaps)); assert(bs_new->job == NULL); assert(bs_new->dev == NULL); assert(bs_new->in_use == 0); assert(bs_new->io_limits_enabled == false); assert(!throttle_have_timer(&bs_new->throttle_state)); tmp = *bs_new; *bs_new = *bs_old; *bs_old = tmp; /* there are some fields that should not be swapped, move them back */ bdrv_move_feature_fields(&tmp, bs_old); bdrv_move_feature_fields(bs_old, bs_new); bdrv_move_feature_fields(bs_new, &tmp); /* bs_new shouldn't be in bdrv_states even after the swap! */ assert(bs_new->device_name[0] == '\0'); /* Check a few fields that should remain attached to the device */ assert(bs_new->dev == NULL); assert(bs_new->job == NULL); assert(bs_new->in_use == 0); assert(bs_new->io_limits_enabled == false); assert(!throttle_have_timer(&bs_new->throttle_state)); /* insert the nodes back into the graph node list if needed */ if (bs_new->node_name[0] != '\0') { QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs_new, node_list); } if (bs_old->node_name[0] != '\0') { QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs_old, node_list); } bdrv_rebind(bs_new); bdrv_rebind(bs_old); } /* * 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 is required to be anonymous. * * This function does not create any image files. */ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top) { bdrv_swap(bs_new, bs_top); /* The contents of 'tmp' will become bs_top, as we are * swapping bs_new and bs_top contents. */ bs_top->backing_hd = bs_new; bs_top->open_flags &= ~BDRV_O_NO_BACKING; pstrcpy(bs_top->backing_file, sizeof(bs_top->backing_file), bs_new->filename); pstrcpy(bs_top->backing_format, sizeof(bs_top->backing_format), bs_new->drv ? bs_new->drv->format_name : ""); } static void bdrv_delete(BlockDriverState *bs) { assert(!bs->dev); assert(!bs->job); assert(!bs->in_use); assert(!bs->refcnt); assert(QLIST_EMPTY(&bs->dirty_bitmaps)); bdrv_close(bs); /* remove from list, if necessary */ bdrv_make_anon(bs); g_free(bs); } int bdrv_attach_dev(BlockDriverState *bs, void *dev) /* TODO change to DeviceState *dev when all users are qdevified */ { if (bs->dev) { return -EBUSY; } bs->dev = dev; bdrv_iostatus_reset(bs); return 0; } /* TODO qdevified devices don't use this, remove when devices are qdevified */ void bdrv_attach_dev_nofail(BlockDriverState *bs, void *dev) { if (bdrv_attach_dev(bs, dev) < 0) { abort(); } } void bdrv_detach_dev(BlockDriverState *bs, void *dev) /* TODO change to DeviceState *dev when all users are qdevified */ { assert(bs->dev == dev); bs->dev = NULL; bs->dev_ops = NULL; bs->dev_opaque = NULL; bs->guest_block_size = 512; } /* TODO change to return DeviceState * when all users are qdevified */ void *bdrv_get_attached_dev(BlockDriverState *bs) { return bs->dev; } void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops, void *opaque) { bs->dev_ops = ops; bs->dev_opaque = opaque; } void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv, enum MonitorEvent ev, BlockErrorAction action, bool is_read) { QObject *data; const char *action_str; switch (action) { case BDRV_ACTION_REPORT: action_str = "report"; break; case BDRV_ACTION_IGNORE: action_str = "ignore"; break; case BDRV_ACTION_STOP: action_str = "stop"; break; default: abort(); } data = qobject_from_jsonf("{ 'device': %s, 'action': %s, 'operation': %s }", bdrv->device_name, action_str, is_read ? "read" : "write"); monitor_protocol_event(ev, data); qobject_decref(data); } static void bdrv_emit_qmp_eject_event(BlockDriverState *bs, bool ejected) { QObject *data; data = qobject_from_jsonf("{ 'device': %s, 'tray-open': %i }", bdrv_get_device_name(bs), ejected); monitor_protocol_event(QEVENT_DEVICE_TRAY_MOVED, data); qobject_decref(data); } static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load) { if (bs->dev_ops && bs->dev_ops->change_media_cb) { bool tray_was_closed = !bdrv_dev_is_tray_open(bs); bs->dev_ops->change_media_cb(bs->dev_opaque, load); if (tray_was_closed) { /* tray open */ bdrv_emit_qmp_eject_event(bs, true); } if (load) { /* tray close */ bdrv_emit_qmp_eject_event(bs, false); } } } bool bdrv_dev_has_removable_media(BlockDriverState *bs) { return !bs->dev || (bs->dev_ops && bs->dev_ops->change_media_cb); } void bdrv_dev_eject_request(BlockDriverState *bs, bool force) { if (bs->dev_ops && bs->dev_ops->eject_request_cb) { bs->dev_ops->eject_request_cb(bs->dev_opaque, force); } } bool bdrv_dev_is_tray_open(BlockDriverState *bs) { if (bs->dev_ops && bs->dev_ops->is_tray_open) { return bs->dev_ops->is_tray_open(bs->dev_opaque); } return false; } static void bdrv_dev_resize_cb(BlockDriverState *bs) { if (bs->dev_ops && bs->dev_ops->resize_cb) { bs->dev_ops->resize_cb(bs->dev_opaque); } } bool bdrv_dev_is_medium_locked(BlockDriverState *bs) { if (bs->dev_ops && bs->dev_ops->is_medium_locked) { return bs->dev_ops->is_medium_locked(bs->dev_opaque); } return false; } /* * 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->bdrv_check == NULL) { return -ENOTSUP; } memset(res, 0, sizeof(*res)); return bs->drv->bdrv_check(bs, res, fix); } #define COMMIT_BUF_SECTORS 2048 /* commit COW file into the raw image */ int bdrv_commit(BlockDriverState *bs) { BlockDriver *drv = bs->drv; int64_t sector, total_sectors, length, backing_length; int n, ro, open_flags; int ret = 0; uint8_t *buf = NULL; char filename[PATH_MAX]; if (!drv) return -ENOMEDIUM; if (!bs->backing_hd) { return -ENOTSUP; } if (bdrv_in_use(bs) || bdrv_in_use(bs->backing_hd)) { return -EBUSY; } ro = bs->backing_hd->read_only; /* Use pstrcpy (not strncpy): filename must be NUL-terminated. */ pstrcpy(filename, sizeof(filename), bs->backing_hd->filename); open_flags = bs->backing_hd->open_flags; if (ro) { if (bdrv_reopen(bs->backing_hd, open_flags | BDRV_O_RDWR, NULL)) { return -EACCES; } } length = bdrv_getlength(bs); if (length < 0) { ret = length; goto ro_cleanup; } backing_length = bdrv_getlength(bs->backing_hd); if (backing_length < 0) { ret = backing_length; goto ro_cleanup; } /* If our top snapshot is larger than the backing file image, * grow the backing file image if possible. If not possible, * we must return an error */ if (length > backing_length) { ret = bdrv_truncate(bs->backing_hd, length); if (ret < 0) { goto ro_cleanup; } } total_sectors = length >> BDRV_SECTOR_BITS; buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE); for (sector = 0; sector < total_sectors; sector += n) { ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n); if (ret < 0) { goto ro_cleanup; } if (ret) { ret = bdrv_read(bs, sector, buf, n); if (ret < 0) { goto ro_cleanup; } ret = bdrv_write(bs->backing_hd, sector, buf, n); if (ret < 0) { goto ro_cleanup; } } } if (drv->bdrv_make_empty) { ret = drv->bdrv_make_empty(bs); if (ret < 0) { goto ro_cleanup; } bdrv_flush(bs); } /* * Make sure all data we wrote to the backing device is actually * stable on disk. */ if (bs->backing_hd) { bdrv_flush(bs->backing_hd); } ret = 0; ro_cleanup: g_free(buf); if (ro) { /* ignoring error return here */ bdrv_reopen(bs->backing_hd, open_flags & ~BDRV_O_RDWR, NULL); } return ret; } int bdrv_commit_all(void) { BlockDriverState *bs; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { if (bs->drv && bs->backing_hd) { int ret = bdrv_commit(bs); if (ret < 0) { return ret; } } } return 0; } /** * Remove an active request from the tracked requests list * * This function should be called when a tracked request is completing. */ static void tracked_request_end(BdrvTrackedRequest *req) { if (req->serialising) { req->bs->serialising_in_flight--; } QLIST_REMOVE(req, list); qemu_co_queue_restart_all(&req->wait_queue); } /** * Add an active request to the tracked requests list */ static void tracked_request_begin(BdrvTrackedRequest *req, BlockDriverState *bs, int64_t offset, unsigned int bytes, bool is_write) { *req = (BdrvTrackedRequest){ .bs = bs, .offset = offset, .bytes = bytes, .is_write = is_write, .co = qemu_coroutine_self(), .serialising = false, .overlap_offset = offset, .overlap_bytes = bytes, }; qemu_co_queue_init(&req->wait_queue); QLIST_INSERT_HEAD(&bs->tracked_requests, req, list); } static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align) { int64_t overlap_offset = req->offset & ~(align - 1); unsigned int overlap_bytes = ROUND_UP(req->offset + req->bytes, align) - overlap_offset; if (!req->serialising) { req->bs->serialising_in_flight++; req->serialising = true; } req->overlap_offset = MIN(req->overlap_offset, overlap_offset); req->overlap_bytes = MAX(req->overlap_bytes, overlap_bytes); } /** * Round a region to cluster boundaries */ void bdrv_round_to_clusters(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int64_t *cluster_sector_num, int *cluster_nb_sectors) { BlockDriverInfo bdi; if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) { *cluster_sector_num = sector_num; *cluster_nb_sectors = nb_sectors; } else { int64_t c = bdi.cluster_size / BDRV_SECTOR_SIZE; *cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c); *cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num + nb_sectors, c); } } static int bdrv_get_cluster_size(BlockDriverState *bs) { BlockDriverInfo bdi; int ret; ret = bdrv_get_info(bs, &bdi); if (ret < 0 || bdi.cluster_size == 0) { return bs->request_alignment; } else { return bdi.cluster_size; } } static bool tracked_request_overlaps(BdrvTrackedRequest *req, int64_t offset, unsigned int bytes) { /* aaaa bbbb */ if (offset >= req->overlap_offset + req->overlap_bytes) { return false; } /* bbbb aaaa */ if (req->overlap_offset >= offset + bytes) { return false; } return true; } static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self) { BlockDriverState *bs = self->bs; BdrvTrackedRequest *req; bool retry; bool waited = false; if (!bs->serialising_in_flight) { return false; } do { retry = false; QLIST_FOREACH(req, &bs->tracked_requests, list) { if (req == self || (!req->serialising && !self->serialising)) { continue; } if (tracked_request_overlaps(req, self->overlap_offset, self->overlap_bytes)) { /* Hitting this means there was a reentrant request, for * example, a block driver issuing nested requests. This must * never happen since it means deadlock. */ assert(qemu_coroutine_self() != req->co); /* If the request is already (indirectly) waiting for us, or * will wait for us as soon as it wakes up, then just go on * (instead of producing a deadlock in the former case). */ if (!req->waiting_for) { self->waiting_for = req; qemu_co_queue_wait(&req->wait_queue); self->waiting_for = NULL; retry = true; waited = true; break; } } } } while (retry); return waited; } /* * Return values: * 0 - success * -EINVAL - backing format specified, but no file * -ENOSPC - can't update the backing file because no space is left in the * image file header * -ENOTSUP - format driver doesn't support changing the backing file */ int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file, const char *backing_fmt) { BlockDriver *drv = bs->drv; int ret; /* Backing file format doesn't make sense without a backing file */ if (backing_fmt && !backing_file) { return -EINVAL; } if (drv->bdrv_change_backing_file != NULL) { ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt); } else { ret = -ENOTSUP; } if (ret == 0) { pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); } return ret; } /* * Finds the image layer in the chain that has 'bs' as its backing file. * * active is the current topmost image. * * Returns NULL if bs is not found in active's image chain, * or if active == bs. */ BlockDriverState *bdrv_find_overlay(BlockDriverState *active, BlockDriverState *bs) { BlockDriverState *overlay = NULL; BlockDriverState *intermediate; assert(active != NULL); assert(bs != NULL); /* if bs is the same as active, then by definition it has no overlay */ if (active == bs) { return NULL; } intermediate = active; while (intermediate->backing_hd) { if (intermediate->backing_hd == bs) { overlay = intermediate; break; } intermediate = intermediate->backing_hd; } return overlay; } typedef struct BlkIntermediateStates { BlockDriverState *bs; QSIMPLEQ_ENTRY(BlkIntermediateStates) entry; } BlkIntermediateStates; /* * 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 * * Error conditions: * if active == top, that is considered an error * */ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, BlockDriverState *base) { BlockDriverState *intermediate; BlockDriverState *base_bs = NULL; BlockDriverState *new_top_bs = NULL; BlkIntermediateStates *intermediate_state, *next; int ret = -EIO; QSIMPLEQ_HEAD(states_to_delete, BlkIntermediateStates) states_to_delete; QSIMPLEQ_INIT(&states_to_delete); if (!top->drv || !base->drv) { goto exit; } new_top_bs = bdrv_find_overlay(active, top); if (new_top_bs == NULL) { /* we could not find the image above 'top', this is an error */ goto exit; } /* special case of new_top_bs->backing_hd already pointing to base - nothing * to do, no intermediate images */ if (new_top_bs->backing_hd == base) { ret = 0; goto exit; } intermediate = top; /* now we will go down through the list, and add each BDS we find * into our deletion queue, until we hit the 'base' */ while (intermediate) { intermediate_state = g_malloc0(sizeof(BlkIntermediateStates)); intermediate_state->bs = intermediate; QSIMPLEQ_INSERT_TAIL(&states_to_delete, intermediate_state, entry); if (intermediate->backing_hd == base) { base_bs = intermediate->backing_hd; break; } intermediate = intermediate->backing_hd; } if (base_bs == NULL) { /* something went wrong, we did not end at the base. safely * unravel everything, and exit with error */ goto exit; } /* success - we can delete the intermediate states, and link top->base */ ret = bdrv_change_backing_file(new_top_bs, base_bs->filename, base_bs->drv ? base_bs->drv->format_name : ""); if (ret) { goto exit; } new_top_bs->backing_hd = base_bs; bdrv_refresh_limits(new_top_bs); QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) { /* so that bdrv_close() does not recursively close the chain */ intermediate_state->bs->backing_hd = NULL; bdrv_unref(intermediate_state->bs); } ret = 0; exit: QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) { g_free(intermediate_state); } return ret; } static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset, size_t size) { int64_t len; if (!bdrv_is_inserted(bs)) return -ENOMEDIUM; if (bs->growable) return 0; len = bdrv_getlength(bs); if (offset < 0) return -EIO; if ((offset > len) || (len - offset < size)) return -EIO; return 0; } static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num, int nb_sectors) { if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) { return -EIO; } return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE, nb_sectors * BDRV_SECTOR_SIZE); } typedef struct RwCo { BlockDriverState *bs; int64_t offset; QEMUIOVector *qiov; bool is_write; int ret; BdrvRequestFlags flags; } RwCo; static void coroutine_fn bdrv_rw_co_entry(void *opaque) { RwCo *rwco = opaque; if (!rwco->is_write) { rwco->ret = bdrv_co_do_preadv(rwco->bs, rwco->offset, rwco->qiov->size, rwco->qiov, rwco->flags); } else { rwco->ret = bdrv_co_do_pwritev(rwco->bs, rwco->offset, rwco->qiov->size, rwco->qiov, rwco->flags); } } /* * Process a vectored synchronous request using coroutines */ static int bdrv_prwv_co(BlockDriverState *bs, int64_t offset, QEMUIOVector *qiov, bool is_write, BdrvRequestFlags flags) { Coroutine *co; RwCo rwco = { .bs = bs, .offset = offset, .qiov = qiov, .is_write = is_write, .ret = NOT_DONE, .flags = flags, }; /** * In sync call context, when the vcpu is blocked, this throttling timer * will not fire; so the I/O throttling function has to be disabled here * if it has been enabled. */ if (bs->io_limits_enabled) { fprintf(stderr, "Disabling I/O throttling on '%s' due " "to synchronous I/O.\n", bdrv_get_device_name(bs)); bdrv_io_limits_disable(bs); } if (qemu_in_coroutine()) { /* Fast-path if already in coroutine context */ bdrv_rw_co_entry(&rwco); } else { co = qemu_coroutine_create(bdrv_rw_co_entry); qemu_coroutine_enter(co, &rwco); while (rwco.ret == NOT_DONE) { qemu_aio_wait(); } } return rwco.ret; } /* * Process a synchronous request using coroutines */ static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors, bool is_write, BdrvRequestFlags flags) { QEMUIOVector qiov; struct iovec iov = { .iov_base = (void *)buf, .iov_len = nb_sectors * BDRV_SECTOR_SIZE, }; qemu_iovec_init_external(&qiov, &iov, 1); return bdrv_prwv_co(bs, sector_num << BDRV_SECTOR_BITS, &qiov, is_write, flags); } /* return < 0 if error. See bdrv_write() for the return codes */ int bdrv_read(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors) { return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false, 0); } /* Just like bdrv_read(), but with I/O throttling temporarily disabled */ int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors) { bool enabled; int ret; enabled = bs->io_limits_enabled; bs->io_limits_enabled = false; ret = bdrv_read(bs, sector_num, buf, nb_sectors); bs->io_limits_enabled = enabled; return ret; } /* Return < 0 if error. Important errors are: -EIO generic I/O error (may happen for all errors) -ENOMEDIUM No media inserted. -EINVAL Invalid sector number or nb_sectors -EACCES Trying to write a read-only device */ int bdrv_write(BlockDriverState *bs, int64_t sector_num, const uint8_t *buf, int nb_sectors) { return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true, 0); } int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) { return bdrv_rw_co(bs, sector_num, NULL, nb_sectors, true, BDRV_REQ_ZERO_WRITE | flags); } /* * Completely zero out a block device with the help of bdrv_write_zeroes. * The operation is sped up by checking the block status and only writing * zeroes to the device if they currently do not return zeroes. Optional * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). * * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). */ int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags) { int64_t target_size = bdrv_getlength(bs) / BDRV_SECTOR_SIZE; int64_t ret, nb_sectors, sector_num = 0; int n; for (;;) { nb_sectors = target_size - sector_num; if (nb_sectors <= 0) { return 0; } if (nb_sectors > INT_MAX) { nb_sectors = INT_MAX; } ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n); if (ret < 0) { error_report("error getting block status at sector %" PRId64 ": %s", sector_num, strerror(-ret)); return ret; } if (ret & BDRV_BLOCK_ZERO) { sector_num += n; continue; } ret = bdrv_write_zeroes(bs, sector_num, n, flags); if (ret < 0) { error_report("error writing zeroes at sector %" PRId64 ": %s", sector_num, strerror(-ret)); return ret; } sector_num += n; } } int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int bytes) { QEMUIOVector qiov; struct iovec iov = { .iov_base = (void *)buf, .iov_len = bytes, }; int ret; if (bytes < 0) { return -EINVAL; } qemu_iovec_init_external(&qiov, &iov, 1); ret = bdrv_prwv_co(bs, offset, &qiov, false, 0); if (ret < 0) { return ret; } return bytes; } int bdrv_pwritev(BlockDriverState *bs, int64_t offset, QEMUIOVector *qiov) { int ret; ret = bdrv_prwv_co(bs, offset, qiov, true, 0); if (ret < 0) { return ret; } return qiov->size; } int bdrv_pwrite(BlockDriverState *bs, int64_t offset, const void *buf, int bytes) { QEMUIOVector qiov; struct iovec iov = { .iov_base = (void *) buf, .iov_len = bytes, }; if (bytes < 0) { return -EINVAL; } qemu_iovec_init_external(&qiov, &iov, 1); return bdrv_pwritev(bs, offset, &qiov); } /* * Writes to the file and ensures that no writes are reordered across this * request (acts as a barrier) * * Returns 0 on success, -errno in error cases. */ int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset, const void *buf, int count) { int ret; ret = bdrv_pwrite(bs, offset, buf, count); if (ret < 0) { return ret; } /* No flush needed for cache modes that already do it */ if (bs->enable_write_cache) { bdrv_flush(bs); } return 0; } static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { /* Perform I/O through a temporary buffer so that users who scribble over * their read buffer while the operation is in progress do not end up * modifying the image file. This is critical for zero-copy guest I/O * where anything might happen inside guest memory. */ void *bounce_buffer; BlockDriver *drv = bs->drv; struct iovec iov; QEMUIOVector bounce_qiov; int64_t cluster_sector_num; int cluster_nb_sectors; size_t skip_bytes; int ret; /* Cover entire cluster so no additional backing file I/O is required when * allocating cluster in the image file. */ bdrv_round_to_clusters(bs, sector_num, nb_sectors, &cluster_sector_num, &cluster_nb_sectors); trace_bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, cluster_sector_num, cluster_nb_sectors); iov.iov_len = cluster_nb_sectors * BDRV_SECTOR_SIZE; iov.iov_base = bounce_buffer = qemu_blockalign(bs, iov.iov_len); qemu_iovec_init_external(&bounce_qiov, &iov, 1); ret = drv->bdrv_co_readv(bs, cluster_sector_num, cluster_nb_sectors, &bounce_qiov); if (ret < 0) { goto err; } if (drv->bdrv_co_write_zeroes && buffer_is_zero(bounce_buffer, iov.iov_len)) { ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num, cluster_nb_sectors, 0); } else { /* This does not change the data on the disk, it is not necessary * to flush even in cache=writethrough mode. */ ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors, &bounce_qiov); } if (ret < 0) { /* It might be okay to ignore write errors for guest requests. If this * is a deliberate copy-on-read then we don't want to ignore the error. * Simply report it in all cases. */ goto err; } skip_bytes = (sector_num - cluster_sector_num) * BDRV_SECTOR_SIZE; qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes, nb_sectors * BDRV_SECTOR_SIZE); err: qemu_vfree(bounce_buffer); return ret; } /* * Forwards an already correctly aligned request to the BlockDriver. This * handles copy on read and zeroing after EOF; any other features must be * implemented by the caller. */ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, int64_t align, QEMUIOVector *qiov, int flags) { BlockDriver *drv = bs->drv; int ret; int64_t sector_num = offset >> BDRV_SECTOR_BITS; unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS; assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); /* Handle Copy on Read and associated serialisation */ if (flags & BDRV_REQ_COPY_ON_READ) { /* If we touch the same cluster it counts as an overlap. This * guarantees that allocating writes will be serialized and not race * with each other for the same cluster. For example, in copy-on-read * it ensures that the CoR read and write operations are atomic and * guest writes cannot interleave between them. */ mark_request_serialising(req, bdrv_get_cluster_size(bs)); } wait_serialising_requests(req); if (flags & BDRV_REQ_COPY_ON_READ) { int pnum; ret = bdrv_is_allocated(bs, sector_num, nb_sectors, &pnum); if (ret < 0) { goto out; } if (!ret || pnum != nb_sectors) { ret = bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, qiov); goto out; } } /* Forward the request to the BlockDriver */ if (!(bs->zero_beyond_eof && bs->growable)) { ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); } else { /* Read zeros after EOF of growable BDSes */ int64_t len, total_sectors, max_nb_sectors; len = bdrv_getlength(bs); if (len < 0) { ret = len; goto out; } total_sectors = DIV_ROUND_UP(len, BDRV_SECTOR_SIZE); max_nb_sectors = ROUND_UP(MAX(0, total_sectors - sector_num), align >> BDRV_SECTOR_BITS); if (max_nb_sectors > 0) { ret = drv->bdrv_co_readv(bs, sector_num, MIN(nb_sectors, max_nb_sectors), qiov); } else { ret = 0; } /* Reading beyond end of file is supposed to produce zeroes */ if (ret == 0 && total_sectors < sector_num + nb_sectors) { uint64_t offset = MAX(0, total_sectors - sector_num); uint64_t bytes = (sector_num + nb_sectors - offset) * BDRV_SECTOR_SIZE; qemu_iovec_memset(qiov, offset * BDRV_SECTOR_SIZE, 0, bytes); } } out: return ret; } /* * Handle a read request in coroutine context */ static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs, int64_t offset, unsigned int bytes, QEMUIOVector *qiov, BdrvRequestFlags flags) { BlockDriver *drv = bs->drv; BdrvTrackedRequest req; /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); uint8_t *head_buf = NULL; uint8_t *tail_buf = NULL; QEMUIOVector local_qiov; bool use_local_qiov = false; int ret; if (!drv) { return -ENOMEDIUM; } if (bdrv_check_byte_request(bs, offset, bytes)) { return -EIO; } if (bs->copy_on_read) { flags |= BDRV_REQ_COPY_ON_READ; } /* throttling disk I/O */ if (bs->io_limits_enabled) { bdrv_io_limits_intercept(bs, bytes, false); } /* Align read if necessary by padding qiov */ if (offset & (align - 1)) { head_buf = qemu_blockalign(bs, align); qemu_iovec_init(&local_qiov, qiov->niov + 2); qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1)); qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); use_local_qiov = true; bytes += offset & (align - 1); offset = offset & ~(align - 1); } if ((offset + bytes) & (align - 1)) { if (!use_local_qiov) { qemu_iovec_init(&local_qiov, qiov->niov + 1); qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); use_local_qiov = true; } tail_buf = qemu_blockalign(bs, align); qemu_iovec_add(&local_qiov, tail_buf, align - ((offset + bytes) & (align - 1))); bytes = ROUND_UP(bytes, align); } tracked_request_begin(&req, bs, offset, bytes, false); ret = bdrv_aligned_preadv(bs, &req, offset, bytes, align, use_local_qiov ? &local_qiov : qiov, flags); tracked_request_end(&req); if (use_local_qiov) { qemu_iovec_destroy(&local_qiov); qemu_vfree(head_buf); qemu_vfree(tail_buf); } return ret; } static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, BdrvRequestFlags flags) { if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) { return -EINVAL; } return bdrv_co_do_preadv(bs, sector_num << BDRV_SECTOR_BITS, nb_sectors << BDRV_SECTOR_BITS, qiov, flags); } int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { trace_bdrv_co_readv(bs, sector_num, nb_sectors); return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0); } int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { trace_bdrv_co_copy_on_readv(bs, sector_num, nb_sectors); return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, BDRV_REQ_COPY_ON_READ); } /* if no limit is specified in the BlockLimits use a default * of 32768 512-byte sectors (16 MiB) per request. */ #define MAX_WRITE_ZEROES_DEFAULT 32768 static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) { BlockDriver *drv = bs->drv; QEMUIOVector qiov; struct iovec iov = {0}; int ret = 0; int max_write_zeroes = bs->bl.max_write_zeroes ? bs->bl.max_write_zeroes : MAX_WRITE_ZEROES_DEFAULT; while (nb_sectors > 0 && !ret) { int num = nb_sectors; /* Align request. Block drivers can expect the "bulk" of the request * to be aligned. */ if (bs->bl.write_zeroes_alignment && num > bs->bl.write_zeroes_alignment) { if (sector_num % bs->bl.write_zeroes_alignment != 0) { /* Make a small request up to the first aligned sector. */ num = bs->bl.write_zeroes_alignment; num -= sector_num % bs->bl.write_zeroes_alignment; } else if ((sector_num + num) % bs->bl.write_zeroes_alignment != 0) { /* Shorten the request to the last aligned sector. num cannot * underflow because num > bs->bl.write_zeroes_alignment. */ num -= (sector_num + num) % bs->bl.write_zeroes_alignment; } } /* limit request size */ if (num > max_write_zeroes) { num = max_write_zeroes; } ret = -ENOTSUP; /* First try the efficient write zeroes operation */ if (drv->bdrv_co_write_zeroes) { ret = drv->bdrv_co_write_zeroes(bs, sector_num, num, flags); } if (ret == -ENOTSUP) { /* Fall back to bounce buffer if write zeroes is unsupported */ iov.iov_len = num * BDRV_SECTOR_SIZE; if (iov.iov_base == NULL) { iov.iov_base = qemu_blockalign(bs, num * BDRV_SECTOR_SIZE); memset(iov.iov_base, 0, num * BDRV_SECTOR_SIZE); } qemu_iovec_init_external(&qiov, &iov, 1); ret = drv->bdrv_co_writev(bs, sector_num, num, &qiov); /* Keep bounce buffer around if it is big enough for all * all future requests. */ if (num < max_write_zeroes) { qemu_vfree(iov.iov_base); iov.iov_base = NULL; } } sector_num += num; nb_sectors -= num; } qemu_vfree(iov.iov_base); return ret; } /* * Forwards an already correctly aligned write request to the BlockDriver. */ static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs, BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags) { BlockDriver *drv = bs->drv; bool waited; int ret; int64_t sector_num = offset >> BDRV_SECTOR_BITS; unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS; assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); waited = wait_serialising_requests(req); assert(!waited || !req->serialising); assert(req->overlap_offset <= offset); assert(offset + bytes <= req->overlap_offset + req->overlap_bytes); ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req); if (ret < 0) { /* Do nothing, write notifier decided to fail this request */ } else if (flags & BDRV_REQ_ZERO_WRITE) { BLKDBG_EVENT(bs, BLKDBG_PWRITEV_ZERO); ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags); } else { BLKDBG_EVENT(bs, BLKDBG_PWRITEV); ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov); } BLKDBG_EVENT(bs, BLKDBG_PWRITEV_DONE); if (ret == 0 && !bs->enable_write_cache) { ret = bdrv_co_flush(bs); } bdrv_set_dirty(bs, sector_num, nb_sectors); if (bs->wr_highest_sector < sector_num + nb_sectors - 1) { bs->wr_highest_sector = sector_num + nb_sectors - 1; } if (bs->growable && ret >= 0) { bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors); } return ret; } /* * Handle a write request in coroutine context */ static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs, int64_t offset, unsigned int bytes, QEMUIOVector *qiov, BdrvRequestFlags flags) { BdrvTrackedRequest req; /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); uint8_t *head_buf = NULL; uint8_t *tail_buf = NULL; QEMUIOVector local_qiov; bool use_local_qiov = false; int ret; if (!bs->drv) { return -ENOMEDIUM; } if (bs->read_only) { return -EACCES; } if (bdrv_check_byte_request(bs, offset, bytes)) { return -EIO; } /* throttling disk I/O */ if (bs->io_limits_enabled) { bdrv_io_limits_intercept(bs, bytes, true); } /* * Align write if necessary by performing a read-modify-write cycle. * Pad qiov with the read parts and be sure to have a tracked request not * only for bdrv_aligned_pwritev, but also for the reads of the RMW cycle. */ tracked_request_begin(&req, bs, offset, bytes, true); if (offset & (align - 1)) { QEMUIOVector head_qiov; struct iovec head_iov; mark_request_serialising(&req, align); wait_serialising_requests(&req); head_buf = qemu_blockalign(bs, align); head_iov = (struct iovec) { .iov_base = head_buf, .iov_len = align, }; qemu_iovec_init_external(&head_qiov, &head_iov, 1); BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_HEAD); ret = bdrv_aligned_preadv(bs, &req, offset & ~(align - 1), align, align, &head_qiov, 0); if (ret < 0) { goto fail; } BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD); qemu_iovec_init(&local_qiov, qiov->niov + 2); qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1)); qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); use_local_qiov = true; bytes += offset & (align - 1); offset = offset & ~(align - 1); } if ((offset + bytes) & (align - 1)) { QEMUIOVector tail_qiov; struct iovec tail_iov; size_t tail_bytes; bool waited; mark_request_serialising(&req, align); waited = wait_serialising_requests(&req); assert(!waited || !use_local_qiov); tail_buf = qemu_blockalign(bs, align); tail_iov = (struct iovec) { .iov_base = tail_buf, .iov_len = align, }; qemu_iovec_init_external(&tail_qiov, &tail_iov, 1); BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_TAIL); ret = bdrv_aligned_preadv(bs, &req, (offset + bytes) & ~(align - 1), align, align, &tail_qiov, 0); if (ret < 0) { goto fail; } BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL); if (!use_local_qiov) { qemu_iovec_init(&local_qiov, qiov->niov + 1); qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); use_local_qiov = true; } tail_bytes = (offset + bytes) & (align - 1); qemu_iovec_add(&local_qiov, tail_buf + tail_bytes, align - tail_bytes); bytes = ROUND_UP(bytes, align); } ret = bdrv_aligned_pwritev(bs, &req, offset, bytes, use_local_qiov ? &local_qiov : qiov, flags); fail: tracked_request_end(&req); if (use_local_qiov) { qemu_iovec_destroy(&local_qiov); } qemu_vfree(head_buf); qemu_vfree(tail_buf); return ret; } static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, BdrvRequestFlags flags) { if (nb_sectors < 0 || nb_sectors > (INT_MAX >> BDRV_SECTOR_BITS)) { return -EINVAL; } return bdrv_co_do_pwritev(bs, sector_num << BDRV_SECTOR_BITS, nb_sectors << BDRV_SECTOR_BITS, qiov, flags); } int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { trace_bdrv_co_writev(bs, sector_num, nb_sectors); return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov, 0); } int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs, int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) { trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags); if (!(bs->open_flags & BDRV_O_UNMAP)) { flags &= ~BDRV_REQ_MAY_UNMAP; } return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL, BDRV_REQ_ZERO_WRITE | flags); } /** * Truncate file to 'offset' bytes (needed only for file protocols) */ int bdrv_truncate(BlockDriverState *bs, int64_t offset) { BlockDriver *drv = bs->drv; int ret; if (!drv) return -ENOMEDIUM; if (!drv->bdrv_truncate) return -ENOTSUP; if (bs->read_only) return -EACCES; if (bdrv_in_use(bs)) return -EBUSY; ret = drv->bdrv_truncate(bs, offset); if (ret == 0) { ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); bdrv_dev_resize_cb(bs); } 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); } return -ENOTSUP; } /** * Length of a file in bytes. Return < 0 if error or unknown. */ int64_t bdrv_getlength(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 * 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 length; length = bdrv_getlength(bs); if (length < 0) length = 0; else length = length >> BDRV_SECTOR_BITS; *nb_sectors_ptr = length; } void bdrv_set_on_error(BlockDriverState *bs, BlockdevOnError on_read_error, BlockdevOnError on_write_error) { bs->on_read_error = on_read_error; bs->on_write_error = on_write_error; } BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, bool is_read) { return is_read ? bs->on_read_error : bs->on_write_error; } BlockErrorAction bdrv_get_error_action(BlockDriverState *bs, bool is_read, int error) { BlockdevOnError on_err = is_read ? bs->on_read_error : bs->on_write_error; switch (on_err) { case BLOCKDEV_ON_ERROR_ENOSPC: return (error == ENOSPC) ? BDRV_ACTION_STOP : BDRV_ACTION_REPORT; case BLOCKDEV_ON_ERROR_STOP: return BDRV_ACTION_STOP; case BLOCKDEV_ON_ERROR_REPORT: return BDRV_ACTION_REPORT; case BLOCKDEV_ON_ERROR_IGNORE: return BDRV_ACTION_IGNORE; default: abort(); } } /* This is done by device models because, while the block layer knows * about the error, it does not know whether an operation comes from * the device or the block layer (from a job, for example). */ void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action, bool is_read, int error) { assert(error >= 0); bdrv_emit_qmp_error_event(bs, QEVENT_BLOCK_IO_ERROR, action, is_read); if (action == BDRV_ACTION_STOP) { vm_stop(RUN_STATE_IO_ERROR); bdrv_iostatus_set_err(bs, error); } } int bdrv_is_read_only(BlockDriverState *bs) { return bs->read_only; } int bdrv_is_sg(BlockDriverState *bs) { return bs->sg; } int bdrv_enable_write_cache(BlockDriverState *bs) { return bs->enable_write_cache; } void bdrv_set_enable_write_cache(BlockDriverState *bs, bool wce) { bs->enable_write_cache = wce; /* so a reopen() will preserve wce */ if (wce) { bs->open_flags |= BDRV_O_CACHE_WB; } else { bs->open_flags &= ~BDRV_O_CACHE_WB; } } int bdrv_is_encrypted(BlockDriverState *bs) { if (bs->backing_hd && bs->backing_hd->encrypted) return 1; return bs->encrypted; } int bdrv_key_required(BlockDriverState *bs) { BlockDriverState *backing_hd = bs->backing_hd; if (backing_hd && backing_hd->encrypted && !backing_hd->valid_key) return 1; return (bs->encrypted && !bs->valid_key); } int bdrv_set_key(BlockDriverState *bs, const char *key) { int ret; if (bs->backing_hd && bs->backing_hd->encrypted) { ret = bdrv_set_key(bs->backing_hd, key); if (ret < 0) return ret; if (!bs->encrypted) return 0; } if (!bs->encrypted) { return -EINVAL; } else if (!bs->drv || !bs->drv->bdrv_set_key) { return -ENOMEDIUM; } ret = bs->drv->bdrv_set_key(bs, key); if (ret < 0) { bs->valid_key = 0; } else if (!bs->valid_key) { bs->valid_key = 1; /* call the change callback now, we skipped it on open */ bdrv_dev_change_media_cb(bs, true); } return ret; } const char *bdrv_get_format_name(BlockDriverState *bs) { return bs->drv ? bs->drv->format_name : NULL; } void bdrv_iterate_format(void (*it)(void *opaque, const char *name), void *opaque) { BlockDriver *drv; QLIST_FOREACH(drv, &bdrv_drivers, list) { it(opaque, drv->format_name); } } /* This function is to find block backend bs */ BlockDriverState *bdrv_find(const char *name) { BlockDriverState *bs; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { if (!strcmp(name, bs->device_name)) { return bs; } } return NULL; } /* 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(void) { BlockDeviceInfoList *list, *entry; BlockDriverState *bs; list = NULL; QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { entry = g_malloc0(sizeof(*entry)); entry->value = bdrv_block_device_info(bs); entry->next = list; list = entry; } return list; } BlockDriverState *bdrv_lookup_bs(const char *device, const char *node_name, Error **errp) { BlockDriverState *bs = NULL; if (device) { bs = bdrv_find(device); if (bs) { 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; } BlockDriverState *bdrv_next(BlockDriverState *bs) { if (!bs) { return QTAILQ_FIRST(&bdrv_states); } return QTAILQ_NEXT(bs, device_list); } void bdrv_iterate(void (*it)(void *opaque, BlockDriverState *bs), void *opaque) { BlockDriverState *bs; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { it(opaque, bs); } } const char *bdrv_get_device_name(BlockDriverState *bs) { return bs->device_name; } int bdrv_get_flags(BlockDriverState *bs) { return bs->open_flags; } int bdrv_flush_all(void) { BlockDriverState *bs; int result = 0; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { int ret = bdrv_flush(bs); if (ret < 0 && !result) { result = ret; } } return result; } int bdrv_has_zero_init_1(BlockDriverState *bs) { return 1; } int bdrv_has_zero_init(BlockDriverState *bs) { assert(bs->drv); /* If BS is a copy on write image, it is initialized to the contents of the base image, which may not be zeroes. */ if (bs->backing_hd) { return 0; } if (bs->drv->bdrv_has_zero_init) { return bs->drv->bdrv_has_zero_init(bs); } /* safe default */ return 0; } bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs) { BlockDriverInfo bdi; if (bs->backing_hd) { return false; } if (bdrv_get_info(bs, &bdi) == 0) { return bdi.unallocated_blocks_are_zero; } return false; } bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) { BlockDriverInfo bdi; if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) { return false; } if (bdrv_get_info(bs, &bdi) == 0) { return bdi.can_write_zeroes_with_unmap; } return false; } typedef struct BdrvCoGetBlockStatusData { BlockDriverState *bs; BlockDriverState *base; int64_t sector_num; int nb_sectors; int *pnum; int64_t ret; bool done; } BdrvCoGetBlockStatusData; /* * Returns true iff the specified sector is present in the disk image. Drivers * not implementing the functionality are assumed to not support backing files, * hence all their sectors are reported as allocated. * * If 'sector_num' is beyond the end of the disk image the return value is 0 * and 'pnum' is set to 0. * * 'pnum' is set to the number of sectors (including and immediately following * the specified sector) that are known to be in the same * allocated/unallocated state. * * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes * beyond the end of the disk image it will be clamped. */ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum) { int64_t length; int64_t n; int64_t ret, ret2; length = bdrv_getlength(bs); if (length < 0) { return length; } if (sector_num >= (length >> BDRV_SECTOR_BITS)) { *pnum = 0; return 0; } n = bs->total_sectors - sector_num; if (n < nb_sectors) { nb_sectors = n; } if (!bs->drv->bdrv_co_get_block_status) { *pnum = nb_sectors; ret = BDRV_BLOCK_DATA; if (bs->drv->protocol_name) { ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE); } return ret; } ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum); if (ret < 0) { *pnum = 0; return ret; } if (ret & BDRV_BLOCK_RAW) { assert(ret & BDRV_BLOCK_OFFSET_VALID); return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, *pnum, pnum); } if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) { if (bdrv_unallocated_blocks_are_zero(bs)) { ret |= BDRV_BLOCK_ZERO; } else if (bs->backing_hd) { BlockDriverState *bs2 = bs->backing_hd; int64_t length2 = bdrv_getlength(bs2); if (length2 >= 0 && sector_num >= (length2 >> BDRV_SECTOR_BITS)) { ret |= BDRV_BLOCK_ZERO; } } } if (bs->file && (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && (ret & BDRV_BLOCK_OFFSET_VALID)) { ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, *pnum, pnum); if (ret2 >= 0) { /* Ignore errors. This is just providing extra information, it * is useful but not necessary. */ ret |= (ret2 & BDRV_BLOCK_ZERO); } } return ret; } /* Coroutine wrapper for bdrv_get_block_status() */ static void coroutine_fn bdrv_get_block_status_co_entry(void *opaque) { BdrvCoGetBlockStatusData *data = opaque; BlockDriverState *bs = data->bs; data->ret = bdrv_co_get_block_status(bs, data->sector_num, data->nb_sectors, data->pnum); data->done = true; } /* * Synchronous wrapper around bdrv_co_get_block_status(). * * See bdrv_co_get_block_status() for details. */ int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum) { Coroutine *co; BdrvCoGetBlockStatusData data = { .bs = bs, .sector_num = sector_num, .nb_sectors = nb_sectors, .pnum = pnum, .done = false, }; if (qemu_in_coroutine()) { /* Fast-path if already in coroutine context */ bdrv_get_block_status_co_entry(&data); } else { co = qemu_coroutine_create(bdrv_get_block_status_co_entry); qemu_coroutine_enter(co, &data); while (!data.done) { qemu_aio_wait(); } } return data.ret; } int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum) { int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum); if (ret < 0) { return ret; } return (ret & BDRV_BLOCK_DATA) || ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs)); } /* * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] * * Return true if the given sector is allocated in any image between * BASE and TOP (inclusive). BASE can be NULL to check if the given * sector is allocated in any image of the chain. Return false otherwise. * * 'pnum' is set to the number of sectors (including and immediately following * the specified sector) that are known to be in the same * allocated/unallocated state. * */ int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base, int64_t sector_num, int nb_sectors, int *pnum) { BlockDriverState *intermediate; int ret, n = nb_sectors; intermediate = top; while (intermediate && intermediate != base) { int pnum_inter; ret = bdrv_is_allocated(intermediate, sector_num, nb_sectors, &pnum_inter); if (ret < 0) { return ret; } else if (ret) { *pnum = pnum_inter; return 1; } /* * [sector_num, nb_sectors] is unallocated on top but intermediate * might have * * [sector_num+x, nr_sectors] allocated. */ if (n > pnum_inter && (intermediate == top || sector_num + pnum_inter < intermediate->total_sectors)) { n = pnum_inter; } intermediate = intermediate->backing_hd; } *pnum = n; return 0; } const char *bdrv_get_encrypted_filename(BlockDriverState *bs) { if (bs->backing_hd && bs->backing_hd->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_write_compressed(BlockDriverState *bs, int64_t sector_num, const uint8_t *buf, int nb_sectors) { BlockDriver *drv = bs->drv; if (!drv) return -ENOMEDIUM; if (!drv->bdrv_write_compressed) return -ENOTSUP; if (bdrv_check_request(bs, sector_num, nb_sectors)) return -EIO; assert(QLIST_EMPTY(&bs->dirty_bitmaps)); return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors); } int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BlockDriver *drv = bs->drv; if (!drv) return -ENOMEDIUM; if (!drv->bdrv_get_info) return -ENOTSUP; memset(bdi, 0, sizeof(*bdi)); return drv->bdrv_get_info(bs, bdi); } ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_get_specific_info) { return drv->bdrv_get_specific_info(bs); } return NULL; } int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, int64_t pos, int size) { QEMUIOVector qiov; struct iovec iov = { .iov_base = (void *) buf, .iov_len = size, }; qemu_iovec_init_external(&qiov, &iov, 1); return bdrv_writev_vmstate(bs, &qiov, pos); } int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) { BlockDriver *drv = bs->drv; if (!drv) { return -ENOMEDIUM; } else if (drv->bdrv_save_vmstate) { return drv->bdrv_save_vmstate(bs, qiov, pos); } else if (bs->file) { return bdrv_writev_vmstate(bs->file, qiov, pos); } return -ENOTSUP; } int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, int64_t pos, int size) { BlockDriver *drv = bs->drv; if (!drv) return -ENOMEDIUM; if (drv->bdrv_load_vmstate) return drv->bdrv_load_vmstate(bs, buf, pos, size); if (bs->file) return bdrv_load_vmstate(bs->file, buf, pos, size); return -ENOTSUP; } 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; } 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; } 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; } 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; } if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) { return bs->drv->bdrv_debug_is_suspended(bs, tag); } return false; } int bdrv_is_snapshot(BlockDriverState *bs) { return !!(bs->open_flags & BDRV_O_SNAPSHOT); } /* backing_file can either be relative, or absolute, or a protocol. If it is * relative, it must be relative to the chain. So, passing in bs->filename * from a BDS as backing_file should not be done, as that may be relative to * the CWD rather than the chain. */ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, const char *backing_file) { char *filename_full = NULL; char *backing_file_full = NULL; char *filename_tmp = NULL; int is_protocol = 0; BlockDriverState *curr_bs = NULL; BlockDriverState *retval = NULL; if (!bs || !bs->drv || !backing_file) { return NULL; } filename_full = g_malloc(PATH_MAX); backing_file_full = g_malloc(PATH_MAX); filename_tmp = g_malloc(PATH_MAX); is_protocol = path_has_protocol(backing_file); for (curr_bs = bs; curr_bs->backing_hd; curr_bs = curr_bs->backing_hd) { /* 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_hd; break; } } else { /* If not an absolute filename path, make it relative to the current * image's filename path */ path_combine(filename_tmp, PATH_MAX, curr_bs->filename, backing_file); /* We are going to compare absolute pathnames */ if (!realpath(filename_tmp, filename_full)) { continue; } /* We need to make sure the backing filename we are comparing against * is relative to the current image filename (or absolute) */ path_combine(filename_tmp, PATH_MAX, curr_bs->filename, curr_bs->backing_file); if (!realpath(filename_tmp, backing_file_full)) { continue; } if (strcmp(backing_file_full, filename_full) == 0) { retval = curr_bs->backing_hd; break; } } } g_free(filename_full); g_free(backing_file_full); g_free(filename_tmp); return retval; } int bdrv_get_backing_file_depth(BlockDriverState *bs) { if (!bs->drv) { return 0; } if (!bs->backing_hd) { return 0; } return 1 + bdrv_get_backing_file_depth(bs->backing_hd); } BlockDriverState *bdrv_find_base(BlockDriverState *bs) { BlockDriverState *curr_bs = NULL; if (!bs) { return NULL; } curr_bs = bs; while (curr_bs->backing_hd) { curr_bs = curr_bs->backing_hd; } return curr_bs; } /**************************************************************/ /* async I/Os */ BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque) { trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque); return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, cb, opaque, false); } BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque) { trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque); return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, cb, opaque, true); } BlockDriverAIOCB *bdrv_aio_write_zeroes(BlockDriverState *bs, int64_t sector_num, int nb_sectors, BdrvRequestFlags flags, BlockDriverCompletionFunc *cb, void *opaque) { trace_bdrv_aio_write_zeroes(bs, sector_num, nb_sectors, flags, opaque); return bdrv_co_aio_rw_vector(bs, sector_num, NULL, nb_sectors, BDRV_REQ_ZERO_WRITE | flags, cb, opaque, true); } typedef struct MultiwriteCB { int error; int num_requests; int num_callbacks; struct { BlockDriverCompletionFunc *cb; void *opaque; QEMUIOVector *free_qiov; } callbacks[]; } MultiwriteCB; static void multiwrite_user_cb(MultiwriteCB *mcb) { int i; for (i = 0; i < mcb->num_callbacks; i++) { mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error); if (mcb->callbacks[i].free_qiov) { qemu_iovec_destroy(mcb->callbacks[i].free_qiov); } g_free(mcb->callbacks[i].free_qiov); } } static void multiwrite_cb(void *opaque, int ret) { MultiwriteCB *mcb = opaque; trace_multiwrite_cb(mcb, ret); if (ret < 0 && !mcb->error) { mcb->error = ret; } mcb->num_requests--; if (mcb->num_requests == 0) { multiwrite_user_cb(mcb); g_free(mcb); } } static int multiwrite_req_compare(const void *a, const void *b) { const BlockRequest *req1 = a, *req2 = b; /* * Note that we can't simply subtract req2->sector from req1->sector * here as that could overflow the return value. */ if (req1->sector > req2->sector) { return 1; } else if (req1->sector < req2->sector) { return -1; } else { return 0; } } /* * Takes a bunch of requests and tries to merge them. Returns the number of * requests that remain after merging. */ static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs, int num_reqs, MultiwriteCB *mcb) { int i, outidx; // Sort requests by start sector qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare); // Check if adjacent requests touch the same clusters. If so, combine them, // filling up gaps with zero sectors. outidx = 0; for (i = 1; i < num_reqs; i++) { int merge = 0; int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors; // Handle exactly sequential writes and overlapping writes. if (reqs[i].sector <= oldreq_last) { merge = 1; } if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) { merge = 0; } if (merge) { size_t size; QEMUIOVector *qiov = g_malloc0(sizeof(*qiov)); qemu_iovec_init(qiov, reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1); // Add the first request to the merged one. If the requests are // overlapping, drop the last sectors of the first request. size = (reqs[i].sector - reqs[outidx].sector) << 9; qemu_iovec_concat(qiov, reqs[outidx].qiov, 0, size); // We should need to add any zeros between the two requests assert (reqs[i].sector <= oldreq_last); // Add the second request qemu_iovec_concat(qiov, reqs[i].qiov, 0, reqs[i].qiov->size); reqs[outidx].nb_sectors = qiov->size >> 9; reqs[outidx].qiov = qiov; mcb->callbacks[i].free_qiov = reqs[outidx].qiov; } else { outidx++; reqs[outidx].sector = reqs[i].sector; reqs[outidx].nb_sectors = reqs[i].nb_sectors; reqs[outidx].qiov = reqs[i].qiov; } } return outidx + 1; } /* * Submit multiple AIO write requests at once. * * On success, the function returns 0 and all requests in the reqs array have * been submitted. In error case this function returns -1, and any of the * requests may or may not be submitted yet. In particular, this means that the * callback will be called for some of the requests, for others it won't. The * caller must check the error field of the BlockRequest to wait for the right * callbacks (if error != 0, no callback will be called). * * The implementation may modify the contents of the reqs array, e.g. to merge * requests. However, the fields opaque and error are left unmodified as they * are used to signal failure for a single request to the caller. */ int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs) { MultiwriteCB *mcb; int i; /* don't submit writes if we don't have a medium */ if (bs->drv == NULL) { for (i = 0; i < num_reqs; i++) { reqs[i].error = -ENOMEDIUM; } return -1; } if (num_reqs == 0) { return 0; } // Create MultiwriteCB structure mcb = g_malloc0(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks)); mcb->num_requests = 0; mcb->num_callbacks = num_reqs; for (i = 0; i < num_reqs; i++) { mcb->callbacks[i].cb = reqs[i].cb; mcb->callbacks[i].opaque = reqs[i].opaque; } // Check for mergable requests num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb); trace_bdrv_aio_multiwrite(mcb, mcb->num_callbacks, num_reqs); /* Run the aio requests. */ mcb->num_requests = num_reqs; for (i = 0; i < num_reqs; i++) { bdrv_co_aio_rw_vector(bs, reqs[i].sector, reqs[i].qiov, reqs[i].nb_sectors, reqs[i].flags, multiwrite_cb, mcb, true); } return 0; } void bdrv_aio_cancel(BlockDriverAIOCB *acb) { acb->aiocb_info->cancel(acb); } /**************************************************************/ /* async block device emulation */ typedef struct BlockDriverAIOCBSync { BlockDriverAIOCB common; QEMUBH *bh; int ret; /* vector translation state */ QEMUIOVector *qiov; uint8_t *bounce; int is_write; } BlockDriverAIOCBSync; static void bdrv_aio_cancel_em(BlockDriverAIOCB *blockacb) { BlockDriverAIOCBSync *acb = container_of(blockacb, BlockDriverAIOCBSync, common); qemu_bh_delete(acb->bh); acb->bh = NULL; qemu_aio_release(acb); } static const AIOCBInfo bdrv_em_aiocb_info = { .aiocb_size = sizeof(BlockDriverAIOCBSync), .cancel = bdrv_aio_cancel_em, }; static void bdrv_aio_bh_cb(void *opaque) { BlockDriverAIOCBSync *acb = opaque; if (!acb->is_write) qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size); qemu_vfree(acb->bounce); acb->common.cb(acb->common.opaque, acb->ret); qemu_bh_delete(acb->bh); acb->bh = NULL; qemu_aio_release(acb); } static BlockDriverAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque, int is_write) { BlockDriverAIOCBSync *acb; acb = qemu_aio_get(&bdrv_em_aiocb_info, bs, cb, opaque); acb->is_write = is_write; acb->qiov = qiov; acb->bounce = qemu_blockalign(bs, qiov->size); acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb); if (is_write) { qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size); acb->ret = bs->drv->bdrv_write(bs, sector_num, acb->bounce, nb_sectors); } else { acb->ret = bs->drv->bdrv_read(bs, sector_num, acb->bounce, nb_sectors); } qemu_bh_schedule(acb->bh); return &acb->common; } static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque) { return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); } static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque) { return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1); } typedef struct BlockDriverAIOCBCoroutine { BlockDriverAIOCB common; BlockRequest req; bool is_write; bool *done; QEMUBH* bh; } BlockDriverAIOCBCoroutine; static void bdrv_aio_co_cancel_em(BlockDriverAIOCB *blockacb) { BlockDriverAIOCBCoroutine *acb = container_of(blockacb, BlockDriverAIOCBCoroutine, common); bool done = false; acb->done = &done; while (!done) { qemu_aio_wait(); } } static const AIOCBInfo bdrv_em_co_aiocb_info = { .aiocb_size = sizeof(BlockDriverAIOCBCoroutine), .cancel = bdrv_aio_co_cancel_em, }; static void bdrv_co_em_bh(void *opaque) { BlockDriverAIOCBCoroutine *acb = opaque; acb->common.cb(acb->common.opaque, acb->req.error); if (acb->done) { *acb->done = true; } qemu_bh_delete(acb->bh); qemu_aio_release(acb); } /* Invoke bdrv_co_do_readv/bdrv_co_do_writev */ static void coroutine_fn bdrv_co_do_rw(void *opaque) { BlockDriverAIOCBCoroutine *acb = opaque; BlockDriverState *bs = acb->common.bs; if (!acb->is_write) { acb->req.error = bdrv_co_do_readv(bs, acb->req.sector, acb->req.nb_sectors, acb->req.qiov, acb->req.flags); } else { acb->req.error = bdrv_co_do_writev(bs, acb->req.sector, acb->req.nb_sectors, acb->req.qiov, acb->req.flags); } acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); qemu_bh_schedule(acb->bh); } static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BdrvRequestFlags flags, BlockDriverCompletionFunc *cb, void *opaque, bool is_write) { Coroutine *co; BlockDriverAIOCBCoroutine *acb; acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); acb->req.sector = sector_num; acb->req.nb_sectors = nb_sectors; acb->req.qiov = qiov; acb->req.flags = flags; acb->is_write = is_write; acb->done = NULL; co = qemu_coroutine_create(bdrv_co_do_rw); qemu_coroutine_enter(co, acb); return &acb->common; } static void coroutine_fn bdrv_aio_flush_co_entry(void *opaque) { BlockDriverAIOCBCoroutine *acb = opaque; BlockDriverState *bs = acb->common.bs; acb->req.error = bdrv_co_flush(bs); acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); qemu_bh_schedule(acb->bh); } BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs, BlockDriverCompletionFunc *cb, void *opaque) { trace_bdrv_aio_flush(bs, opaque); Coroutine *co; BlockDriverAIOCBCoroutine *acb; acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); acb->done = NULL; co = qemu_coroutine_create(bdrv_aio_flush_co_entry); qemu_coroutine_enter(co, acb); return &acb->common; } static void coroutine_fn bdrv_aio_discard_co_entry(void *opaque) { BlockDriverAIOCBCoroutine *acb = opaque; BlockDriverState *bs = acb->common.bs; acb->req.error = bdrv_co_discard(bs, acb->req.sector, acb->req.nb_sectors); acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); qemu_bh_schedule(acb->bh); } BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque) { Coroutine *co; BlockDriverAIOCBCoroutine *acb; trace_bdrv_aio_discard(bs, sector_num, nb_sectors, opaque); acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); acb->req.sector = sector_num; acb->req.nb_sectors = nb_sectors; acb->done = NULL; co = qemu_coroutine_create(bdrv_aio_discard_co_entry); qemu_coroutine_enter(co, acb); return &acb->common; } void bdrv_init(void) { module_call_init(MODULE_INIT_BLOCK); } void bdrv_init_with_whitelist(void) { use_bdrv_whitelist = 1; bdrv_init(); } void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs, BlockDriverCompletionFunc *cb, void *opaque) { BlockDriverAIOCB *acb; acb = g_slice_alloc(aiocb_info->aiocb_size); acb->aiocb_info = aiocb_info; acb->bs = bs; acb->cb = cb; acb->opaque = opaque; return acb; } void qemu_aio_release(void *p) { BlockDriverAIOCB *acb = p; g_slice_free1(acb->aiocb_info->aiocb_size, acb); } /**************************************************************/ /* Coroutine block device emulation */ typedef struct CoroutineIOCompletion { Coroutine *coroutine; int ret; } CoroutineIOCompletion; static void bdrv_co_io_em_complete(void *opaque, int ret) { CoroutineIOCompletion *co = opaque; co->ret = ret; qemu_coroutine_enter(co->coroutine, NULL); } static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *iov, bool is_write) { CoroutineIOCompletion co = { .coroutine = qemu_coroutine_self(), }; BlockDriverAIOCB *acb; if (is_write) { acb = bs->drv->bdrv_aio_writev(bs, sector_num, iov, nb_sectors, bdrv_co_io_em_complete, &co); } else { acb = bs->drv->bdrv_aio_readv(bs, sector_num, iov, nb_sectors, bdrv_co_io_em_complete, &co); } trace_bdrv_co_io_em(bs, sector_num, nb_sectors, is_write, acb); if (!acb) { return -EIO; } qemu_coroutine_yield(); return co.ret; } static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *iov) { return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false); } static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *iov) { return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true); } static void coroutine_fn bdrv_flush_co_entry(void *opaque) { RwCo *rwco = opaque; rwco->ret = bdrv_co_flush(rwco->bs); } int coroutine_fn bdrv_co_flush(BlockDriverState *bs) { int ret; if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { return 0; } /* Write back cached data to the OS even with cache=unsafe */ BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS); if (bs->drv->bdrv_co_flush_to_os) { ret = bs->drv->bdrv_co_flush_to_os(bs); if (ret < 0) { return ret; } } /* But don't actually force it to the disk with cache=unsafe */ if (bs->open_flags & BDRV_O_NO_FLUSH) { goto flush_parent; } BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK); if (bs->drv->bdrv_co_flush_to_disk) { ret = bs->drv->bdrv_co_flush_to_disk(bs); } else if (bs->drv->bdrv_aio_flush) { BlockDriverAIOCB *acb; CoroutineIOCompletion co = { .coroutine = qemu_coroutine_self(), }; acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co); if (acb == NULL) { ret = -EIO; } else { qemu_coroutine_yield(); ret = co.ret; } } else { /* * Some block drivers always operate in either writethrough or unsafe * mode and don't support bdrv_flush therefore. Usually qemu doesn't * know how the server works (because the behaviour is hardcoded or * depends on server-side configuration), so we can't ensure that * everything is safe on disk. Returning an error doesn't work because * that would break guests even if the server operates in writethrough * mode. * * Let's hope the user knows what he's doing. */ ret = 0; } if (ret < 0) { return ret; } /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH * in the case of cache=unsafe, so there are no useless flushes. */ flush_parent: return bdrv_co_flush(bs->file); } void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) { Error *local_err = NULL; int ret; if (!bs->drv) { return; } if (bs->drv->bdrv_invalidate_cache) { bs->drv->bdrv_invalidate_cache(bs, &local_err); } else if (bs->file) { bdrv_invalidate_cache(bs->file, &local_err); } if (local_err) { error_propagate(errp, local_err); return; } ret = refresh_total_sectors(bs, bs->total_sectors); if (ret < 0) { error_setg_errno(errp, -ret, "Could not refresh total sector count"); return; } } void bdrv_invalidate_cache_all(Error **errp) { BlockDriverState *bs; Error *local_err = NULL; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { bdrv_invalidate_cache(bs, &local_err); if (local_err) { error_propagate(errp, local_err); return; } } } void bdrv_clear_incoming_migration_all(void) { BlockDriverState *bs; QTAILQ_FOREACH(bs, &bdrv_states, device_list) { bs->open_flags = bs->open_flags & ~(BDRV_O_INCOMING); } } int bdrv_flush(BlockDriverState *bs) { Coroutine *co; RwCo rwco = { .bs = bs, .ret = NOT_DONE, }; if (qemu_in_coroutine()) { /* Fast-path if already in coroutine context */ bdrv_flush_co_entry(&rwco); } else { co = qemu_coroutine_create(bdrv_flush_co_entry); qemu_coroutine_enter(co, &rwco); while (rwco.ret == NOT_DONE) { qemu_aio_wait(); } } return rwco.ret; } typedef struct DiscardCo { BlockDriverState *bs; int64_t sector_num; int nb_sectors; int ret; } DiscardCo; static void coroutine_fn bdrv_discard_co_entry(void *opaque) { DiscardCo *rwco = opaque; rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors); } /* if no limit is specified in the BlockLimits use a default * of 32768 512-byte sectors (16 MiB) per request. */ #define MAX_DISCARD_DEFAULT 32768 int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors) { int max_discard; if (!bs->drv) { return -ENOMEDIUM; } else if (bdrv_check_request(bs, sector_num, nb_sectors)) { return -EIO; } else if (bs->read_only) { return -EROFS; } bdrv_reset_dirty(bs, sector_num, nb_sectors); /* Do nothing if disabled. */ if (!(bs->open_flags & BDRV_O_UNMAP)) { return 0; } if (!bs->drv->bdrv_co_discard && !bs->drv->bdrv_aio_discard) { return 0; } max_discard = bs->bl.max_discard ? bs->bl.max_discard : MAX_DISCARD_DEFAULT; while (nb_sectors > 0) { int ret; int num = nb_sectors; /* align request */ if (bs->bl.discard_alignment && num >= bs->bl.discard_alignment && sector_num % bs->bl.discard_alignment) { if (num > bs->bl.discard_alignment) { num = bs->bl.discard_alignment; } num -= sector_num % bs->bl.discard_alignment; } /* limit request size */ if (num > max_discard) { num = max_discard; } if (bs->drv->bdrv_co_discard) { ret = bs->drv->bdrv_co_discard(bs, sector_num, num); } else { BlockDriverAIOCB *acb; CoroutineIOCompletion co = { .coroutine = qemu_coroutine_self(), }; acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors, bdrv_co_io_em_complete, &co); if (acb == NULL) { return -EIO; } else { qemu_coroutine_yield(); ret = co.ret; } } if (ret && ret != -ENOTSUP) { return ret; } sector_num += num; nb_sectors -= num; } return 0; } int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors) { Coroutine *co; DiscardCo rwco = { .bs = bs, .sector_num = sector_num, .nb_sectors = nb_sectors, .ret = NOT_DONE, }; if (qemu_in_coroutine()) { /* Fast-path if already in coroutine context */ bdrv_discard_co_entry(&rwco); } else { co = qemu_coroutine_create(bdrv_discard_co_entry); qemu_coroutine_enter(co, &rwco); while (rwco.ret == NOT_DONE) { qemu_aio_wait(); } } return rwco.ret; } /**************************************************************/ /* removable device support */ /** * Return TRUE if the media is present */ int bdrv_is_inserted(BlockDriverState *bs) { BlockDriver *drv = bs->drv; if (!drv) return 0; if (!drv->bdrv_is_inserted) return 1; return drv->bdrv_is_inserted(bs); } /** * Return whether the media changed since the last call to this * function, or -ENOTSUP if we don't know. Most drivers don't know. */ int bdrv_media_changed(BlockDriverState *bs) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_media_changed) { return drv->bdrv_media_changed(bs); } return -ENOTSUP; } /** * If eject_flag is TRUE, eject the media. Otherwise, close the tray */ void bdrv_eject(BlockDriverState *bs, bool eject_flag) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_eject) { drv->bdrv_eject(bs, eject_flag); } if (bs->device_name[0] != '\0') { bdrv_emit_qmp_eject_event(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); } } /* needed for generic scsi interface */ int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_ioctl) return drv->bdrv_ioctl(bs, req, buf); return -ENOTSUP; } BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs, unsigned long int req, void *buf, BlockDriverCompletionFunc *cb, void *opaque) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_aio_ioctl) return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque); return NULL; } void bdrv_set_guest_block_size(BlockDriverState *bs, int align) { bs->guest_block_size = align; } void *qemu_blockalign(BlockDriverState *bs, size_t size) { return qemu_memalign(bdrv_opt_mem_align(bs), size); } /* * Check if all memory in this vector is sector aligned. */ bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov) { int i; size_t alignment = bdrv_opt_mem_align(bs); for (i = 0; i < qiov->niov; i++) { if ((uintptr_t) qiov->iov[i].iov_base % alignment) { return false; } if (qiov->iov[i].iov_len % alignment) { return false; } } return true; } BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity) { int64_t bitmap_size; BdrvDirtyBitmap *bitmap; assert((granularity & (granularity - 1)) == 0); granularity >>= BDRV_SECTOR_BITS; assert(granularity); bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS); bitmap = g_malloc0(sizeof(BdrvDirtyBitmap)); bitmap->bitmap = hbitmap_alloc(bitmap_size, ffs(granularity) - 1); QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list); return bitmap; } void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) { BdrvDirtyBitmap *bm, *next; QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) { if (bm == bitmap) { QLIST_REMOVE(bitmap, list); hbitmap_free(bitmap->bitmap); g_free(bitmap); return; } } } BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs) { BdrvDirtyBitmap *bm; BlockDirtyInfoList *list = NULL; BlockDirtyInfoList **plist = &list; QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) { BlockDirtyInfo *info = g_malloc0(sizeof(BlockDirtyInfo)); BlockDirtyInfoList *entry = g_malloc0(sizeof(BlockDirtyInfoList)); info->count = bdrv_get_dirty_count(bs, bm); info->granularity = ((int64_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bm->bitmap)); entry->value = info; *plist = entry; plist = &entry->next; } return list; } int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector) { if (bitmap) { return hbitmap_get(bitmap->bitmap, sector); } else { return 0; } } void bdrv_dirty_iter_init(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, HBitmapIter *hbi) { hbitmap_iter_init(hbi, bitmap->bitmap, 0); } void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors) { BdrvDirtyBitmap *bitmap; QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors); } } void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors) { BdrvDirtyBitmap *bitmap; QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors); } } int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) { return hbitmap_count(bitmap->bitmap); } /* 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) { assert(bs->refcnt > 0); if (--bs->refcnt == 0) { bdrv_delete(bs); } } void bdrv_set_in_use(BlockDriverState *bs, int in_use) { assert(bs->in_use != in_use); bs->in_use = in_use; } int bdrv_in_use(BlockDriverState *bs) { return bs->in_use; } void bdrv_iostatus_enable(BlockDriverState *bs) { bs->iostatus_enabled = true; bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK; } /* The I/O status is only enabled if the drive explicitly * enables it _and_ the VM is configured to stop on errors */ bool bdrv_iostatus_is_enabled(const BlockDriverState *bs) { return (bs->iostatus_enabled && (bs->on_write_error == BLOCKDEV_ON_ERROR_ENOSPC || bs->on_write_error == BLOCKDEV_ON_ERROR_STOP || bs->on_read_error == BLOCKDEV_ON_ERROR_STOP)); } void bdrv_iostatus_disable(BlockDriverState *bs) { bs->iostatus_enabled = false; } void bdrv_iostatus_reset(BlockDriverState *bs) { if (bdrv_iostatus_is_enabled(bs)) { bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK; if (bs->job) { block_job_iostatus_reset(bs->job); } } } void bdrv_iostatus_set_err(BlockDriverState *bs, int error) { assert(bdrv_iostatus_is_enabled(bs)); if (bs->iostatus == BLOCK_DEVICE_IO_STATUS_OK) { bs->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE : BLOCK_DEVICE_IO_STATUS_FAILED; } } void bdrv_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie, int64_t bytes, enum BlockAcctType type) { assert(type < BDRV_MAX_IOTYPE); cookie->bytes = bytes; cookie->start_time_ns = get_clock(); cookie->type = type; } void bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie) { assert(cookie->type < BDRV_MAX_IOTYPE); bs->nr_bytes[cookie->type] += cookie->bytes; bs->nr_ops[cookie->type]++; bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns; } void bdrv_img_create(const char *filename, const char *fmt, const char *base_filename, const char *base_fmt, char *options, uint64_t img_size, int flags, Error **errp, bool quiet) { QEMUOptionParameter *param = NULL, *create_options = NULL; QEMUOptionParameter *backing_fmt, *backing_file, *size; BlockDriver *drv, *proto_drv; BlockDriver *backing_drv = NULL; 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); if (!proto_drv) { error_setg(errp, "Unknown protocol '%s'", filename); return; } create_options = append_option_parameters(create_options, drv->create_options); create_options = append_option_parameters(create_options, proto_drv->create_options); /* Create parameter list with default values */ param = parse_option_parameters("", create_options, param); set_option_parameter_int(param, BLOCK_OPT_SIZE, img_size); /* Parse -o options */ if (options) { param = parse_option_parameters(options, create_options, param); if (param == NULL) { error_setg(errp, "Invalid options for file format '%s'.", fmt); goto out; } } if (base_filename) { if (set_option_parameter(param, BLOCK_OPT_BACKING_FILE, base_filename)) { error_setg(errp, "Backing file not supported for file format '%s'", fmt); goto out; } } if (base_fmt) { if (set_option_parameter(param, BLOCK_OPT_BACKING_FMT, base_fmt)) { error_setg(errp, "Backing file format not supported for file " "format '%s'", fmt); goto out; } } backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE); if (backing_file && backing_file->value.s) { if (!strcmp(filename, backing_file->value.s)) { error_setg(errp, "Error: Trying to create an image with the " "same filename as the backing file"); goto out; } } backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT); if (backing_fmt && backing_fmt->value.s) { backing_drv = bdrv_find_format(backing_fmt->value.s); if (!backing_drv) { error_setg(errp, "Unknown backing file format '%s'", backing_fmt->value.s); goto out; } } // The size for the image must always be specified, with one exception: // If we are using a backing file, we can obtain the size from there size = get_option_parameter(param, BLOCK_OPT_SIZE); if (size && size->value.n == -1) { if (backing_file && backing_file->value.s) { BlockDriverState *bs; uint64_t size; char buf[32]; int back_flags; /* backing files always opened read-only */ back_flags = flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); bs = NULL; ret = bdrv_open(&bs, backing_file->value.s, NULL, NULL, back_flags, backing_drv, &local_err); if (ret < 0) { error_setg_errno(errp, -ret, "Could not open '%s': %s", backing_file->value.s, error_get_pretty(local_err)); error_free(local_err); local_err = NULL; goto out; } bdrv_get_geometry(bs, &size); size *= 512; snprintf(buf, sizeof(buf), "%" PRId64, size); set_option_parameter(param, BLOCK_OPT_SIZE, buf); bdrv_unref(bs); } else { error_setg(errp, "Image creation needs a size parameter"); goto out; } } if (!quiet) { printf("Formatting '%s', fmt=%s ", filename, fmt); print_option_parameters(param); puts(""); } ret = bdrv_create(drv, filename, param, &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 (get_option_parameter(create_options, BLOCK_OPT_CLUSTER_SIZE)) { 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: free_option_parameters(create_options); free_option_parameters(param); if (local_err) { error_propagate(errp, local_err); } } AioContext *bdrv_get_aio_context(BlockDriverState *bs) { /* Currently BlockDriverState always uses the main loop AioContext */ return qemu_get_aio_context(); } void bdrv_add_before_write_notifier(BlockDriverState *bs, NotifierWithReturn *notifier) { notifier_with_return_list_add(&bs->before_write_notifiers, notifier); } int bdrv_amend_options(BlockDriverState *bs, QEMUOptionParameter *options) { if (bs->drv->bdrv_amend_options == NULL) { return -ENOTSUP; } return bs->drv->bdrv_amend_options(bs, options); } /* This function will be called by the bdrv_recurse_is_first_non_filter method * of block filter and by bdrv_is_first_non_filter. * It is used to test if the given bs is the candidate or recurse more in the * node graph. */ bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs, BlockDriverState *candidate) { /* return false if basic checks fails */ if (!bs || !bs->drv) { return false; } /* the code reached a non block filter driver -> check if the bs is * the same as the candidate. It's the recursion termination condition. */ if (!bs->drv->is_filter) { return bs == candidate; } /* Down this path the driver is a block filter driver */ /* If the block filter recursion method is defined use it to recurse down * the node graph. */ if (bs->drv->bdrv_recurse_is_first_non_filter) { return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate); } /* the driver is a block filter but don't allow to recurse -> return false */ return false; } /* This function checks if the candidate is the first non filter bs down it's * bs chain. Since we don't have pointers to parents it explore all bs chains * from the top. Some filters can choose not to pass down the recursion. */ bool bdrv_is_first_non_filter(BlockDriverState *candidate) { BlockDriverState *bs; /* walk down the bs forest recursively */ QTAILQ_FOREACH(bs, &bdrv_states, device_list) { bool perm; /* try to recurse in this top level bs */ perm = bdrv_recurse_is_first_non_filter(bs, candidate); /* candidate is the first non filter */ if (perm) { return true; } } return false; }