1 /* 2 * QEMU Block backends 3 * 4 * Copyright (C) 2014-2016 Red Hat, Inc. 5 * 6 * Authors: 7 * Markus Armbruster <armbru@redhat.com>, 8 * 9 * This work is licensed under the terms of the GNU LGPL, version 2.1 10 * or later. See the COPYING.LIB file in the top-level directory. 11 */ 12 13 #ifndef BLOCK_BACKEND_H 14 #define BLOCK_BACKEND_H 15 16 #include "qemu/iov.h" 17 #include "block/throttle-groups.h" 18 19 /* 20 * TODO Have to include block/block.h for a bunch of block layer 21 * types. Unfortunately, this pulls in the whole BlockDriverState 22 * API, which we don't want used by many BlockBackend users. Some of 23 * the types belong here, and the rest should be split into a common 24 * header and one for the BlockDriverState API. 25 */ 26 #include "block/block.h" 27 28 /* Callbacks for block device models */ 29 typedef struct BlockDevOps { 30 /* 31 * Runs when virtual media changed (monitor commands eject, change) 32 * Argument load is true on load and false on eject. 33 * Beware: doesn't run when a host device's physical media 34 * changes. Sure would be useful if it did. 35 * Device models with removable media must implement this callback. 36 */ 37 void (*change_media_cb)(void *opaque, bool load); 38 /* 39 * Runs when an eject request is issued from the monitor, the tray 40 * is closed, and the medium is locked. 41 * Device models that do not implement is_medium_locked will not need 42 * this callback. Device models that can lock the medium or tray might 43 * want to implement the callback and unlock the tray when "force" is 44 * true, even if they do not support eject requests. 45 */ 46 void (*eject_request_cb)(void *opaque, bool force); 47 /* 48 * Is the virtual tray open? 49 * Device models implement this only when the device has a tray. 50 */ 51 bool (*is_tray_open)(void *opaque); 52 /* 53 * Is the virtual medium locked into the device? 54 * Device models implement this only when device has such a lock. 55 */ 56 bool (*is_medium_locked)(void *opaque); 57 /* 58 * Runs when the size changed (e.g. monitor command block_resize) 59 */ 60 void (*resize_cb)(void *opaque); 61 } BlockDevOps; 62 63 /* This struct is embedded in (the private) BlockBackend struct and contains 64 * fields that must be public. This is in particular for QLIST_ENTRY() and 65 * friends so that BlockBackends can be kept in lists outside block-backend.c */ 66 typedef struct BlockBackendPublic { 67 /* I/O throttling has its own locking, but also some fields are 68 * protected by the AioContext lock. 69 */ 70 71 /* Protected by AioContext lock. */ 72 CoQueue throttled_reqs[2]; 73 74 /* Nonzero if the I/O limits are currently being ignored; generally 75 * it is zero. */ 76 unsigned int io_limits_disabled; 77 78 /* The following fields are protected by the ThrottleGroup lock. 79 * See the ThrottleGroup documentation for details. 80 * throttle_state tells us if I/O limits are configured. */ 81 ThrottleState *throttle_state; 82 ThrottleTimers throttle_timers; 83 unsigned pending_reqs[2]; 84 QLIST_ENTRY(BlockBackendPublic) round_robin; 85 } BlockBackendPublic; 86 87 BlockBackend *blk_new(void); 88 BlockBackend *blk_new_open(const char *filename, const char *reference, 89 QDict *options, int flags, Error **errp); 90 int blk_get_refcnt(BlockBackend *blk); 91 void blk_ref(BlockBackend *blk); 92 void blk_unref(BlockBackend *blk); 93 void blk_remove_all_bs(void); 94 const char *blk_name(BlockBackend *blk); 95 BlockBackend *blk_by_name(const char *name); 96 BlockBackend *blk_next(BlockBackend *blk); 97 bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp); 98 void monitor_remove_blk(BlockBackend *blk); 99 100 BlockBackendPublic *blk_get_public(BlockBackend *blk); 101 BlockBackend *blk_by_public(BlockBackendPublic *public); 102 103 BlockDriverState *blk_bs(BlockBackend *blk); 104 void blk_remove_bs(BlockBackend *blk); 105 void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs); 106 bool bdrv_has_blk(BlockDriverState *bs); 107 bool bdrv_is_root_node(BlockDriverState *bs); 108 109 void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow); 110 void blk_iostatus_enable(BlockBackend *blk); 111 bool blk_iostatus_is_enabled(const BlockBackend *blk); 112 BlockDeviceIoStatus blk_iostatus(const BlockBackend *blk); 113 void blk_iostatus_disable(BlockBackend *blk); 114 void blk_iostatus_reset(BlockBackend *blk); 115 void blk_iostatus_set_err(BlockBackend *blk, int error); 116 int blk_attach_dev(BlockBackend *blk, DeviceState *dev); 117 void blk_attach_dev_legacy(BlockBackend *blk, void *dev); 118 void blk_detach_dev(BlockBackend *blk, void *dev); 119 void *blk_get_attached_dev(BlockBackend *blk); 120 BlockBackend *blk_by_dev(void *dev); 121 BlockBackend *blk_by_qdev_id(const char *id, Error **errp); 122 void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, void *opaque); 123 int blk_pread_unthrottled(BlockBackend *blk, int64_t offset, uint8_t *buf, 124 int count); 125 int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset, 126 unsigned int bytes, QEMUIOVector *qiov, 127 BdrvRequestFlags flags); 128 int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset, 129 unsigned int bytes, QEMUIOVector *qiov, 130 BdrvRequestFlags flags); 131 int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset, 132 int count, BdrvRequestFlags flags); 133 BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset, 134 int count, BdrvRequestFlags flags, 135 BlockCompletionFunc *cb, void *opaque); 136 int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags); 137 int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int count); 138 int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int count, 139 BdrvRequestFlags flags); 140 int64_t blk_getlength(BlockBackend *blk); 141 void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr); 142 int64_t blk_nb_sectors(BlockBackend *blk); 143 BlockAIOCB *blk_aio_preadv(BlockBackend *blk, int64_t offset, 144 QEMUIOVector *qiov, BdrvRequestFlags flags, 145 BlockCompletionFunc *cb, void *opaque); 146 BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset, 147 QEMUIOVector *qiov, BdrvRequestFlags flags, 148 BlockCompletionFunc *cb, void *opaque); 149 BlockAIOCB *blk_aio_flush(BlockBackend *blk, 150 BlockCompletionFunc *cb, void *opaque); 151 BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk, int64_t offset, int count, 152 BlockCompletionFunc *cb, void *opaque); 153 void blk_aio_cancel(BlockAIOCB *acb); 154 void blk_aio_cancel_async(BlockAIOCB *acb); 155 int blk_co_ioctl(BlockBackend *blk, unsigned long int req, void *buf); 156 int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf); 157 BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf, 158 BlockCompletionFunc *cb, void *opaque); 159 int blk_co_pdiscard(BlockBackend *blk, int64_t offset, int count); 160 int blk_co_flush(BlockBackend *blk); 161 int blk_flush(BlockBackend *blk); 162 int blk_commit_all(void); 163 void blk_drain(BlockBackend *blk); 164 void blk_drain_all(void); 165 void blk_set_on_error(BlockBackend *blk, BlockdevOnError on_read_error, 166 BlockdevOnError on_write_error); 167 BlockdevOnError blk_get_on_error(BlockBackend *blk, bool is_read); 168 BlockErrorAction blk_get_error_action(BlockBackend *blk, bool is_read, 169 int error); 170 void blk_error_action(BlockBackend *blk, BlockErrorAction action, 171 bool is_read, int error); 172 int blk_is_read_only(BlockBackend *blk); 173 int blk_is_sg(BlockBackend *blk); 174 int blk_enable_write_cache(BlockBackend *blk); 175 void blk_set_enable_write_cache(BlockBackend *blk, bool wce); 176 void blk_invalidate_cache(BlockBackend *blk, Error **errp); 177 bool blk_is_inserted(BlockBackend *blk); 178 bool blk_is_available(BlockBackend *blk); 179 void blk_lock_medium(BlockBackend *blk, bool locked); 180 void blk_eject(BlockBackend *blk, bool eject_flag); 181 int blk_get_flags(BlockBackend *blk); 182 uint32_t blk_get_max_transfer(BlockBackend *blk); 183 int blk_get_max_iov(BlockBackend *blk); 184 void blk_set_guest_block_size(BlockBackend *blk, int align); 185 void *blk_try_blockalign(BlockBackend *blk, size_t size); 186 void *blk_blockalign(BlockBackend *blk, size_t size); 187 bool blk_op_is_blocked(BlockBackend *blk, BlockOpType op, Error **errp); 188 void blk_op_unblock(BlockBackend *blk, BlockOpType op, Error *reason); 189 void blk_op_block_all(BlockBackend *blk, Error *reason); 190 void blk_op_unblock_all(BlockBackend *blk, Error *reason); 191 AioContext *blk_get_aio_context(BlockBackend *blk); 192 void blk_set_aio_context(BlockBackend *blk, AioContext *new_context); 193 void blk_add_aio_context_notifier(BlockBackend *blk, 194 void (*attached_aio_context)(AioContext *new_context, void *opaque), 195 void (*detach_aio_context)(void *opaque), void *opaque); 196 void blk_remove_aio_context_notifier(BlockBackend *blk, 197 void (*attached_aio_context)(AioContext *, 198 void *), 199 void (*detach_aio_context)(void *), 200 void *opaque); 201 void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify); 202 void blk_add_insert_bs_notifier(BlockBackend *blk, Notifier *notify); 203 void blk_io_plug(BlockBackend *blk); 204 void blk_io_unplug(BlockBackend *blk); 205 BlockAcctStats *blk_get_stats(BlockBackend *blk); 206 BlockBackendRootState *blk_get_root_state(BlockBackend *blk); 207 void blk_update_root_state(BlockBackend *blk); 208 bool blk_get_detect_zeroes_from_root_state(BlockBackend *blk); 209 int blk_get_open_flags_from_root_state(BlockBackend *blk); 210 211 void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk, 212 BlockCompletionFunc *cb, void *opaque); 213 int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset, 214 int count, BdrvRequestFlags flags); 215 int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf, 216 int count); 217 int blk_truncate(BlockBackend *blk, int64_t offset); 218 int blk_pdiscard(BlockBackend *blk, int64_t offset, int count); 219 int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf, 220 int64_t pos, int size); 221 int blk_load_vmstate(BlockBackend *blk, uint8_t *buf, int64_t pos, int size); 222 int blk_probe_blocksizes(BlockBackend *blk, BlockSizes *bsz); 223 int blk_probe_geometry(BlockBackend *blk, HDGeometry *geo); 224 BlockAIOCB *blk_abort_aio_request(BlockBackend *blk, 225 BlockCompletionFunc *cb, 226 void *opaque, int ret); 227 228 void blk_set_io_limits(BlockBackend *blk, ThrottleConfig *cfg); 229 void blk_io_limits_disable(BlockBackend *blk); 230 void blk_io_limits_enable(BlockBackend *blk, const char *group); 231 void blk_io_limits_update_group(BlockBackend *blk, const char *group); 232 233 #endif 234