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| author | Sam Eiderman | 2019-05-23 18:33:37 +0200 |
|---|---|---|
| committer | Max Reitz | 2019-05-28 20:30:55 +0200 |
| commit | 330c72957196e0ae382abcaa97ebf4eb9bc8574f (patch) | |
| tree | c6f6d6855154ae8a323f101560506586b922239f /qemu-img.c | |
| parent | qemu-img: rebase: Reduce reads on in-chain rebase (diff) | |
| download | qemu-330c72957196e0ae382abcaa97ebf4eb9bc8574f.tar.gz qemu-330c72957196e0ae382abcaa97ebf4eb9bc8574f.tar.xz qemu-330c72957196e0ae382abcaa97ebf4eb9bc8574f.zip | |
qemu-img: rebase: Reuse in-chain BlockDriverState
If a chain was detected, don't open a new BlockBackend from the target
backing file which will create a new BlockDriverState. Instead, create
an empty BlockBackend and attach the already open BlockDriverState.
Permissions for blk_new() were copied from blk_new_open() when
flags = 0.
Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
Reviewed-by: Eyal Moscovici <eyal.moscovici@oracle.com>
Signed-off-by: Sagi Amit <sagi.amit@oracle.com>
Co-developed-by: Sagi Amit <sagi.amit@oracle.com>
Signed-off-by: Sam Eiderman <shmuel.eiderman@oracle.com>
Message-id: 20190523163337.4497-4-shmuel.eiderman@oracle.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'qemu-img.c')
| -rw-r--r-- | qemu-img.c | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/qemu-img.c b/qemu-img.c index 2d96a491e2..b0535919b1 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3358,16 +3358,29 @@ static int img_rebase(int argc, char **argv) * in its chain. */ prefix_chain_bs = bdrv_find_backing_image(bs, out_real_path); - - blk_new_backing = blk_new_open(out_real_path, NULL, - options, src_flags, &local_err); - g_free(out_real_path); - if (!blk_new_backing) { - error_reportf_err(local_err, - "Could not open new backing file '%s': ", - out_baseimg); - ret = -1; - goto out; + if (prefix_chain_bs) { + g_free(out_real_path); + blk_new_backing = blk_new(BLK_PERM_CONSISTENT_READ, + BLK_PERM_ALL); + ret = blk_insert_bs(blk_new_backing, prefix_chain_bs, + &local_err); + if (ret < 0) { + error_reportf_err(local_err, + "Could not reuse backing file '%s': ", + out_baseimg); + goto out; + } + } else { + blk_new_backing = blk_new_open(out_real_path, NULL, + options, src_flags, &local_err); + g_free(out_real_path); + if (!blk_new_backing) { + error_reportf_err(local_err, + "Could not open new backing file '%s': ", + out_baseimg); + ret = -1; + goto out; + } } } } |