]> git.proxmox.com Git - mirror_qemu.git/blobdiff - include/block/block.h
Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging
[mirror_qemu.git] / include / block / block.h
index cdec3639a353cf296be4d4d1233ed69863b5cc79..734c9d2f765a982067d93517cc3b9d22c21dfd41 100644 (file)
@@ -43,19 +43,53 @@ typedef struct BlockFragInfo {
 typedef enum {
     BDRV_REQ_COPY_ON_READ       = 0x1,
     BDRV_REQ_ZERO_WRITE         = 0x2,
-    /* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver
-     * is allowed to optimize a write zeroes request by unmapping (discarding)
-     * blocks if it is guaranteed that the result will read back as
-     * zeroes. The flag is only passed to the driver if the block device is
-     * opened with BDRV_O_UNMAP.
+
+    /*
+     * The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate
+     * that the block driver should unmap (discard) blocks if it is guaranteed
+     * that the result will read back as zeroes. The flag is only passed to the
+     * driver if the block device is opened with BDRV_O_UNMAP.
      */
     BDRV_REQ_MAY_UNMAP          = 0x4,
+
+    /*
+     * The BDRV_REQ_NO_SERIALISING flag is only valid for reads and means that
+     * we don't want wait_serialising_requests() during the read operation.
+     *
+     * This flag is used for backup copy-on-write operations, when we need to
+     * read old data before write (write notifier triggered). It is okay since
+     * we already waited for other serializing requests in the initiating write
+     * (see bdrv_aligned_pwritev), and it is necessary if the initiating write
+     * is already serializing (without the flag, the read would deadlock
+     * waiting for the serialising write to complete).
+     */
     BDRV_REQ_NO_SERIALISING     = 0x8,
     BDRV_REQ_FUA                = 0x10,
     BDRV_REQ_WRITE_COMPRESSED   = 0x20,
 
+    /* Signifies that this write request will not change the visible disk
+     * content. */
+    BDRV_REQ_WRITE_UNCHANGED    = 0x40,
+
+    /*
+     * BDRV_REQ_SERIALISING forces request serialisation for writes.
+     * It is used to ensure that writes to the backing file of a backup process
+     * target cannot race with a read of the backup target that defers to the
+     * backing file.
+     *
+     * Note, that BDRV_REQ_SERIALISING is _not_ opposite in meaning to
+     * BDRV_REQ_NO_SERIALISING. A more descriptive name for the latter might be
+     * _DO_NOT_WAIT_FOR_SERIALISING, except that is too long.
+     */
+    BDRV_REQ_SERIALISING        = 0x80,
+
+    /* Execute the request only if the operation can be offloaded or otherwise
+     * be executed efficiently, but return an error instead of using a slow
+     * fallback. */
+    BDRV_REQ_NO_FALLBACK        = 0x100,
+
     /* Mask of valid flags */
-    BDRV_REQ_MASK               = 0x3f,
+    BDRV_REQ_MASK               = 0x1ff,
 } BdrvRequestFlags;
 
 typedef struct BlockSizes {
@@ -86,6 +120,7 @@ typedef struct HDGeometry {
                                       select an appropriate protocol driver,
                                       ignoring the format layer */
 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
+#define BDRV_O_AUTO_RDONLY 0x20000 /* degrade to read-only if opening read-write fails */
 
 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
 
@@ -96,6 +131,7 @@ typedef struct HDGeometry {
 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
 #define BDRV_OPT_READ_ONLY      "read-only"
+#define BDRV_OPT_AUTO_READ_ONLY "auto-read-only"
 #define BDRV_OPT_DISCARD        "discard"
 #define BDRV_OPT_FORCE_SHARE    "force-share"
 
@@ -120,10 +156,15 @@ typedef struct HDGeometry {
  * BDRV_BLOCK_EOF: the returned pnum covers through end of file for this
  *                 layer, set by block layer
  *
- * Internal flag:
+ * Internal flags:
  * BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request
  *                 that the block layer recompute the answer from the returned
  *                 BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
+ * BDRV_BLOCK_RECURSE: request that the block layer will recursively search for
+ *                     zeroes in file child of current block node inside
+ *                     returned region. Only valid together with both
+ *                     BDRV_BLOCK_DATA and BDRV_BLOCK_OFFSET_VALID. Should not
+ *                     appear with BDRV_BLOCK_ZERO.
  *
  * If BDRV_BLOCK_OFFSET_VALID is set, the map parameter represents the
  * host offset within the returned BDS that is allocated for the
@@ -148,6 +189,7 @@ typedef struct HDGeometry {
 #define BDRV_BLOCK_RAW          0x08
 #define BDRV_BLOCK_ALLOCATED    0x10
 #define BDRV_BLOCK_EOF          0x20
+#define BDRV_BLOCK_RECURSE      0x40
 #define BDRV_BLOCK_OFFSET_MASK  BDRV_SECTOR_MASK
 
 typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
@@ -155,6 +197,10 @@ typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
 typedef struct BDRVReopenState {
     BlockDriverState *bs;
     int flags;
+    BlockdevDetectZeroesOptions detect_zeroes;
+    bool backing_missing;
+    bool replace_backing_bs;  /* new_backing_bs is ignored if this is false */
+    BlockDriverState *new_backing_bs; /* If NULL then detach the current bs */
     uint64_t perm, shared_perm;
     QDict *options;
     QDict *explicit_options;
@@ -205,6 +251,9 @@ enum {
      * This permission (which is weaker than BLK_PERM_WRITE) is both enough and
      * required for writes to the block node when the caller promises that
      * the visible disk content doesn't change.
+     *
+     * As the BLK_PERM_WRITE permission is strictly stronger, either is
+     * sufficient to perform an unchanging write.
      */
     BLK_PERM_WRITE_UNCHANGED    = 0x04,
 
@@ -218,6 +267,13 @@ enum {
     BLK_PERM_GRAPH_MOD          = 0x10,
 
     BLK_PERM_ALL                = 0x1f,
+
+    DEFAULT_PERM_PASSTHROUGH    = BLK_PERM_CONSISTENT_READ
+                                 | BLK_PERM_WRITE
+                                 | BLK_PERM_WRITE_UNCHANGED
+                                 | BLK_PERM_RESIZE,
+
+    DEFAULT_PERM_UNCHANGED      = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
 };
 
 char *bdrv_perm_names(uint64_t perm);
@@ -257,18 +313,15 @@ BlockDriverState *bdrv_open(const char *filename, const char *reference,
 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
                                        int flags, Error **errp);
 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
-                                    BlockDriverState *bs,
-                                    QDict *options, int flags);
-int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp);
-int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp);
+                                    BlockDriverState *bs, QDict *options,
+                                    bool keep_old_opts);
+int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp);
+int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
+                              Error **errp);
 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
                         BlockReopenQueue *queue, Error **errp);
 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
-int bdrv_read(BdrvChild *child, int64_t sector_num,
-              uint8_t *buf, int nb_sectors);
-int bdrv_write(BdrvChild *child, int64_t sector_num,
-               const uint8_t *buf, int nb_sectors);
 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
                        int bytes, BdrvRequestFlags flags);
 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
@@ -278,10 +331,6 @@ int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
                      const void *buf, int count);
-int coroutine_fn bdrv_co_readv(BdrvChild *child, int64_t sector_num,
-                               int nb_sectors, QEMUIOVector *qiov);
-int coroutine_fn bdrv_co_writev(BdrvChild *child, int64_t sector_num,
-                               int nb_sectors, QEMUIOVector *qiov);
 /*
  * Efficiently zero a region of the disk image.  Note that this is a regular
  * I/O request like read or write and should have a reasonable size.  This
@@ -293,8 +342,12 @@ int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
     const char *backing_file);
 void bdrv_refresh_filename(BlockDriverState *bs);
+
+int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset,
+                                  PreallocMode prealloc, Error **errp);
 int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
                   Error **errp);
+
 int64_t bdrv_nb_sectors(BlockDriverState *bs);
 int64_t bdrv_getlength(BlockDriverState *bs);
 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
@@ -311,6 +364,11 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
                                     BlockDriverState *bs);
 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
+bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
+                                  Error **errp);
+int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
+                              Error **errp);
+void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
 
 
 typedef struct BdrvCheckResult {
@@ -336,7 +394,8 @@ int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
                                       int64_t total_work_size, void *opaque);
 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
-                       BlockDriverAmendStatusCB *status_cb, void *cb_opaque);
+                       BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
+                       Error **errp);
 
 /* external snapshots */
 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
@@ -370,17 +429,13 @@ void bdrv_drain_all_begin(void);
 void bdrv_drain_all_end(void);
 void bdrv_drain_all(void);
 
-/* Returns NULL when bs == NULL */
-AioWait *bdrv_get_aio_wait(BlockDriverState *bs);
-
 #define BDRV_POLL_WHILE(bs, cond) ({                       \
     BlockDriverState *bs_ = (bs);                          \
-    AIO_WAIT_WHILE(bdrv_get_aio_wait(bs_),                 \
-                   bdrv_get_aio_context(bs_),              \
+    AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
                    cond); })
 
-int bdrv_pdiscard(BlockDriverState *bs, int64_t offset, int bytes);
-int bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes);
+int bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
+int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 int bdrv_has_zero_init_1(BlockDriverState *bs);
 int bdrv_has_zero_init(BlockDriverState *bs);
 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
@@ -394,12 +449,15 @@ int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
                       int64_t *pnum);
 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
-                            int64_t offset, int64_t bytes, int64_t *pnum);
+                            bool include_base, int64_t offset, int64_t bytes,
+                            int64_t *pnum);
 
 bool bdrv_is_read_only(BlockDriverState *bs);
 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
                            bool ignore_allow_rdw, Error **errp);
-int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
+int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
+                              Error **errp);
+bool bdrv_is_writable(BlockDriverState *bs);
 bool bdrv_is_sg(BlockDriverState *bs);
 bool bdrv_is_inserted(BlockDriverState *bs);
 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
@@ -407,11 +465,13 @@ void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 const char *bdrv_get_format_name(BlockDriverState *bs);
 BlockDriverState *bdrv_find_node(const char *node_name);
 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
+XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp);
 BlockDriverState *bdrv_lookup_bs(const char *device,
                                  const char *node_name,
                                  Error **errp);
 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
+BlockDriverState *bdrv_next_all_states(BlockDriverState *bs);
 
 typedef struct BdrvNextIterator {
     enum {
@@ -429,33 +489,30 @@ void bdrv_next_cleanup(BdrvNextIterator *it);
 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
 bool bdrv_is_encrypted(BlockDriverState *bs);
 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
-                         void *opaque);
+                         void *opaque, bool read_only);
 const char *bdrv_get_node_name(const BlockDriverState *bs);
 const char *bdrv_get_device_name(const BlockDriverState *bs);
 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
 int bdrv_get_flags(BlockDriverState *bs);
 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
-ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs);
+ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
+                                          Error **errp);
 void bdrv_round_to_clusters(BlockDriverState *bs,
                             int64_t offset, int64_t bytes,
                             int64_t *cluster_offset,
                             int64_t *cluster_bytes);
 
-const char *bdrv_get_encrypted_filename(BlockDriverState *bs);
 void bdrv_get_backing_filename(BlockDriverState *bs,
                                char *filename, int filename_size);
-void bdrv_get_full_backing_filename(BlockDriverState *bs,
-                                    char *dest, size_t sz, Error **errp);
-void bdrv_get_full_backing_filename_from_filename(const char *backed,
-                                                  const char *backing,
-                                                  char *dest, size_t sz,
-                                                  Error **errp);
+char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp);
+char *bdrv_get_full_backing_filename_from_filename(const char *backed,
+                                                   const char *backing,
+                                                   Error **errp);
+char *bdrv_dirname(BlockDriverState *bs, Error **errp);
 
 int path_has_protocol(const char *path);
 int path_is_absolute(const char *path);
-void path_combine(char *dest, int dest_size,
-                  const char *base_path,
-                  const char *filename);
+char *path_combine(const char *base_path, const char *filename);
 
 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
@@ -527,15 +584,16 @@ AioContext *bdrv_get_aio_context(BlockDriverState *bs);
  */
 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
 
-/**
- * bdrv_set_aio_context:
- *
- * Changes the #AioContext used for fd handlers, timers, and BHs by this
- * BlockDriverState and all its children.
- *
- * This function must be called with iothread lock held.
- */
-void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);
+void bdrv_set_aio_context_ignore(BlockDriverState *bs,
+                                 AioContext *new_context, GSList **ignore);
+int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
+                             Error **errp);
+int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
+                                   BdrvChild *ignore_child, Error **errp);
+bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx,
+                                    GSList **ignore, Error **errp);
+bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
+                              GSList **ignore, Error **errp);
 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
 
@@ -548,7 +606,16 @@ void bdrv_io_unplug(BlockDriverState *bs);
  * Begin a quiesced section of all users of @bs. This is part of
  * bdrv_drained_begin.
  */
-void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore);
+void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore,
+                               bool ignore_bds_parents);
+
+/**
+ * bdrv_parent_drained_begin_single:
+ *
+ * Begin a quiesced section for the parent of @c. If @poll is true, wait for
+ * any pending activity to cease.
+ */
+void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);
 
 /**
  * bdrv_parent_drained_end:
@@ -556,7 +623,23 @@ void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore);
  * End a quiesced section of all users of @bs. This is part of
  * bdrv_drained_end.
  */
-void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore);
+void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore,
+                             bool ignore_bds_parents);
+
+/**
+ * bdrv_drain_poll:
+ *
+ * Poll for pending requests in @bs, its parents (except for @ignore_parent),
+ * and if @recursive is true its children as well (used for subtree drain).
+ *
+ * If @ignore_bds_parents is true, parents that are BlockDriverStates must
+ * ignore the drain request because they will be drained separately (used for
+ * drain_all).
+ *
+ * This is part of bdrv_drained_begin.
+ */
+bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
+                     BdrvChild *ignore_parent, bool ignore_bds_parents);
 
 /**
  * bdrv_drained_begin:
@@ -570,6 +653,15 @@ void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore);
  */
 void bdrv_drained_begin(BlockDriverState *bs);
 
+/**
+ * bdrv_do_drained_begin_quiesce:
+ *
+ * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
+ * running requests to complete.
+ */
+void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
+                                   BdrvChild *parent, bool ignore_bds_parents);
+
 /**
  * Like bdrv_drained_begin, but recursively begins a quiesced section for
  * exclusive access to all child nodes as well.
@@ -604,4 +696,38 @@ bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
  */
 void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
 void bdrv_unregister_buf(BlockDriverState *bs, void *host);
+
+/**
+ *
+ * bdrv_co_copy_range:
+ *
+ * Do offloaded copy between two children. If the operation is not implemented
+ * by the driver, or if the backend storage doesn't support it, a negative
+ * error code will be returned.
+ *
+ * Note: block layer doesn't emulate or fallback to a bounce buffer approach
+ * because usually the caller shouldn't attempt offloaded copy any more (e.g.
+ * calling copy_file_range(2)) after the first error, thus it should fall back
+ * to a read+write path in the caller level.
+ *
+ * @src: Source child to copy data from
+ * @src_offset: offset in @src image to read data
+ * @dst: Destination child to copy data to
+ * @dst_offset: offset in @dst image to write data
+ * @bytes: number of bytes to copy
+ * @flags: request flags. Supported flags:
+ *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
+ *                               write on @dst as if bdrv_co_pwrite_zeroes is
+ *                               called. Used to simplify caller code, or
+ *                               during BlockDriver.bdrv_co_copy_range_from()
+ *                               recursion.
+ *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
+ *                                   requests currently in flight.
+ *
+ * Returns: 0 if succeeded; negative error code if failed.
+ **/
+int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset,
+                                    BdrvChild *dst, uint64_t dst_offset,
+                                    uint64_t bytes, BdrvRequestFlags read_flags,
+                                    BdrvRequestFlags write_flags);
 #endif