From ddf5636dc9e4be894f2ab4a5f803d915478b5099 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Tue, 18 Feb 2014 18:33:06 +0100 Subject: [PATCH] block: Add reference parameter to bdrv_open() Allow bdrv_open() to handle references to existing block devices just as bdrv_file_open() is already capable of. Signed-off-by: Max Reitz Signed-off-by: Kevin Wolf --- block.c | 44 ++++++++++++++++++++++++++++++++++++------- block/qcow2.c | 4 ++-- block/vmdk.c | 3 ++- block/vvfat.c | 2 +- blockdev.c | 12 ++++++------ hw/block/xen_disk.c | 4 ++-- include/block/block.h | 5 +++-- qemu-img.c | 8 ++++---- qemu-io.c | 4 +++- qemu-nbd.c | 2 +- 10 files changed, 61 insertions(+), 27 deletions(-) diff --git a/block.c b/block.c index c39bd3d198..86a32e7192 100644 --- a/block.c +++ b/block.c @@ -1046,7 +1046,7 @@ int bdrv_file_open(BlockDriverState **pbs, const char *filename, } if (!drv->bdrv_file_open) { - ret = bdrv_open(&bs, filename, options, flags, drv, &local_err); + 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); @@ -1125,7 +1125,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) assert(bs->backing_hd == NULL); ret = bdrv_open(&bs->backing_hd, - *backing_filename ? backing_filename : NULL, options, + *backing_filename ? backing_filename : NULL, NULL, options, back_flags, back_drv, &local_err); if (ret < 0) { bs->backing_hd = NULL; @@ -1206,7 +1206,7 @@ int bdrv_open_image(BlockDriverState **pbs, const char *filename, goto done; } - ret = bdrv_open(pbs, filename, image_options, flags, NULL, errp); + ret = bdrv_open(pbs, filename, NULL, image_options, flags, NULL, errp); } else { ret = bdrv_file_open(pbs, filename, reference, image_options, flags, errp); @@ -1227,9 +1227,14 @@ done: * * 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, QDict *options, - int flags, BlockDriver *drv, Error **errp) +int bdrv_open(BlockDriverState **pbs, const char *filename, + const char *reference, QDict *options, int flags, + BlockDriver *drv, Error **errp) { int ret; /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */ @@ -1240,6 +1245,31 @@ int bdrv_open(BlockDriverState **pbs, const char *filename, QDict *options, 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 { @@ -1268,7 +1298,7 @@ int bdrv_open(BlockDriverState **pbs, const char *filename, QDict *options, /* Get the required size from the image */ QINCREF(options); bs1 = NULL; - ret = bdrv_open(&bs1, filename, options, BDRV_O_NO_BACKING, + ret = bdrv_open(&bs1, filename, NULL, options, BDRV_O_NO_BACKING, drv, &local_err); if (ret < 0) { goto fail; @@ -5309,7 +5339,7 @@ void bdrv_img_create(const char *filename, const char *fmt, flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); bs = NULL; - ret = bdrv_open(&bs, backing_file->value.s, NULL, back_flags, + 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", diff --git a/block/qcow2.c b/block/qcow2.c index 309ea12b7d..e2aa5c1b3c 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1553,7 +1553,7 @@ static int qcow2_create2(const char *filename, int64_t total_size, */ BlockDriver* drv = bdrv_find_format("qcow2"); assert(drv != NULL); - ret = bdrv_open(&bs, filename, NULL, + ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, drv, &local_err); if (ret < 0) { error_propagate(errp, local_err); @@ -1604,7 +1604,7 @@ static int qcow2_create2(const char *filename, int64_t total_size, bs = NULL; /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ - ret = bdrv_open(&bs, filename, NULL, + ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING, drv, &local_err); if (local_err) { diff --git a/block/vmdk.c b/block/vmdk.c index 0622db51c4..5df486fa8e 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -1756,7 +1756,8 @@ static int vmdk_create(const char *filename, QEMUOptionParameter *options, } if (backing_file) { BlockDriverState *bs = NULL; - ret = bdrv_open(&bs, backing_file, NULL, BDRV_O_NO_BACKING, NULL, errp); + ret = bdrv_open(&bs, backing_file, NULL, NULL, BDRV_O_NO_BACKING, NULL, + errp); if (ret != 0) { goto exit; } diff --git a/block/vvfat.c b/block/vvfat.c index 0a9f886a20..4bde3bd220 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -2937,7 +2937,7 @@ static int enable_write_target(BDRVVVFATState *s) } s->qcow = NULL; - ret = bdrv_open(&s->qcow, s->qcow_filename, NULL, + ret = bdrv_open(&s->qcow, s->qcow_filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, bdrv_qcow, &local_err); if (ret < 0) { diff --git a/blockdev.c b/blockdev.c index 056ec4c8c1..357f7607ff 100644 --- a/blockdev.c +++ b/blockdev.c @@ -504,7 +504,7 @@ static DriveInfo *blockdev_init(const char *file, QDict *bs_opts, bdrv_flags |= ro ? 0 : BDRV_O_RDWR; QINCREF(bs_opts); - ret = bdrv_open(&dinfo->bdrv, file, bs_opts, bdrv_flags, drv, &error); + ret = bdrv_open(&dinfo->bdrv, file, NULL, bs_opts, bdrv_flags, drv, &error); if (ret < 0) { error_setg(errp, "could not open disk image %s: %s", @@ -1333,7 +1333,7 @@ static void external_snapshot_prepare(BlkTransactionState *common, /* TODO Inherit bs->options or only take explicit options with an * extended QMP command? */ assert(state->new_bs == NULL); - ret = bdrv_open(&state->new_bs, new_image_file, options, + ret = bdrv_open(&state->new_bs, new_image_file, NULL, options, flags | BDRV_O_NO_BACKING, drv, &local_err); /* We will manually add the backing_hd field to the bs later */ if (ret != 0) { @@ -1582,7 +1582,7 @@ static void qmp_bdrv_open_encrypted(BlockDriverState *bs, const char *filename, Error *local_err = NULL; int ret; - ret = bdrv_open(&bs, filename, NULL, bdrv_flags, drv, &local_err); + ret = bdrv_open(&bs, filename, NULL, NULL, bdrv_flags, drv, &local_err); if (ret < 0) { error_propagate(errp, local_err); return; @@ -2019,7 +2019,7 @@ void qmp_drive_backup(const char *device, const char *target, } target_bs = NULL; - ret = bdrv_open(&target_bs, target, NULL, flags, drv, &local_err); + ret = bdrv_open(&target_bs, target, NULL, NULL, flags, drv, &local_err); if (ret < 0) { error_propagate(errp, local_err); return; @@ -2162,8 +2162,8 @@ void qmp_drive_mirror(const char *device, const char *target, * file. */ target_bs = NULL; - ret = bdrv_open(&target_bs, target, NULL, flags | BDRV_O_NO_BACKING, drv, - &local_err); + ret = bdrv_open(&target_bs, target, NULL, NULL, flags | BDRV_O_NO_BACKING, + drv, &local_err); if (ret < 0) { error_propagate(errp, local_err); return; diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c index 14e6d0b56e..61e6ff3208 100644 --- a/hw/block/xen_disk.c +++ b/hw/block/xen_disk.c @@ -813,8 +813,8 @@ static int blk_connect(struct XenDevice *xendev) Error *local_err = NULL; BlockDriver *drv = bdrv_find_whitelisted_format(blkdev->fileproto, readonly); - if (bdrv_open(&blkdev->bs, - blkdev->filename, NULL, qflags, drv, &local_err) != 0) + if (bdrv_open(&blkdev->bs, blkdev->filename, NULL, NULL, qflags, + drv, &local_err) != 0) { xen_be_printf(&blkdev->xendev, 0, "error: %s\n", error_get_pretty(local_err)); diff --git a/include/block/block.h b/include/block/block.h index 980869dd3f..a421041690 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -190,8 +190,9 @@ int bdrv_open_image(BlockDriverState **pbs, const char *filename, QDict *options, const char *bdref_key, int flags, bool force_raw, bool allow_none, Error **errp); int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp); -int bdrv_open(BlockDriverState **pbs, const char *filename, QDict *options, - int flags, BlockDriver *drv, Error **errp); +int bdrv_open(BlockDriverState **pbs, const char *filename, + const char *reference, QDict *options, int flags, + BlockDriver *drv, Error **errp); BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, BlockDriverState *bs, int flags); int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp); diff --git a/qemu-img.c b/qemu-img.c index 59b101347c..79ab3e8cbe 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -289,7 +289,7 @@ static BlockDriverState *bdrv_new_open(const char *filename, drv = NULL; } - ret = bdrv_open(&bs, filename, NULL, flags, drv, &local_err); + ret = bdrv_open(&bs, filename, NULL, NULL, flags, drv, &local_err); if (ret < 0) { error_report("Could not open '%s': %s", filename, error_get_pretty(local_err)); @@ -2312,7 +2312,7 @@ static int img_rebase(int argc, char **argv) bs_old_backing = bdrv_new("old_backing"); bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name)); - ret = bdrv_open(&bs_old_backing, backing_name, NULL, BDRV_O_FLAGS, + ret = bdrv_open(&bs_old_backing, backing_name, NULL, NULL, BDRV_O_FLAGS, old_backing_drv, &local_err); if (ret) { error_report("Could not open old backing file '%s': %s", @@ -2322,8 +2322,8 @@ static int img_rebase(int argc, char **argv) } if (out_baseimg[0]) { bs_new_backing = bdrv_new("new_backing"); - ret = bdrv_open(&bs_new_backing, out_baseimg, NULL, BDRV_O_FLAGS, - new_backing_drv, &local_err); + ret = bdrv_open(&bs_new_backing, out_baseimg, NULL, NULL, + BDRV_O_FLAGS, new_backing_drv, &local_err); if (ret) { error_report("Could not open new backing file '%s': %s", out_baseimg, error_get_pretty(local_err)); diff --git a/qemu-io.c b/qemu-io.c index 8da8f6ec67..61d54c01a0 100644 --- a/qemu-io.c +++ b/qemu-io.c @@ -68,7 +68,9 @@ static int openfile(char *name, int flags, int growable, QDict *opts) } else { qemuio_bs = bdrv_new("hda"); - if (bdrv_open(&qemuio_bs, name, opts, flags, NULL, &local_err) < 0) { + if (bdrv_open(&qemuio_bs, name, NULL, opts, flags, NULL, &local_err) + < 0) + { fprintf(stderr, "%s: can't open device %s: %s\n", progname, name, error_get_pretty(local_err)); error_free(local_err); diff --git a/qemu-nbd.c b/qemu-nbd.c index 0cf123cef2..711162c2ec 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -597,7 +597,7 @@ int main(int argc, char **argv) bs = bdrv_new("hda"); srcpath = argv[optind]; - ret = bdrv_open(&bs, srcpath, NULL, flags, drv, &local_err); + ret = bdrv_open(&bs, srcpath, NULL, NULL, flags, drv, &local_err); if (ret < 0) { errno = -ret; err(EXIT_FAILURE, "Failed to bdrv_open '%s': %s", argv[optind],