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author | Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> | 2017-04-05 11:19:09 +0200 |
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committer | Max Reitz <mreitz@redhat.com> | 2017-04-11 15:33:00 +0200 |
commit | 7a9e51198c24a576275cf509a110d24d7c6ca664 (patch) | |
tree | babdbdcd2c8a486836005c78066c3fc3b8e8ed48 /block | |
parent | aa388ddc36e8032f41cd17bef88cc3ebaeba77c9 (diff) | |
download | qemu-7a9e51198c24a576275cf509a110d24d7c6ca664.zip qemu-7a9e51198c24a576275cf509a110d24d7c6ca664.tar.gz qemu-7a9e51198c24a576275cf509a110d24d7c6ca664.tar.bz2 |
block: pass the right options for BlockDriver.bdrv_open()
raw_open() expects the caller always passing in the right actual
@options parameter. But when trying to applying snapshot on a RBD
image, bdrv_snapshot_goto() calls raw_open() (by calling the
bdrv_open callback on the BlockDriver) with a NULL @options, and
that will result in a Segmentation fault.
For the other non-raw format drivers, it also makes sense to passing
in the actual options, althought they don't trigger the problem so
far.
Let's prepare a @options by adding the "file" key-value pair to a
copy of the actual options that were given for the node (i.e.
bs->options), and pass it to the callback.
BlockDriver.bdrv_open() expects bs->file to be NULL and just
overwrites it with the result from bdrv_open_child(). That means we
should actually make sure it's NULL because otherwise the child BDS
will have a reference count that is 1 too high. So we unconditionally
invoke bdrv_unref_child() before calling BlockDriver.bdrv_open(), and
we wrap everything in bdrv_ref()/bdrv_unref() so the BDS isn't
deleted in the meantime.
Suggested-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Message-id: 20170405091909.36357-2-bjsdjshi@linux.vnet.ibm.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block')
-rw-r--r-- | block/snapshot.c | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/block/snapshot.c b/block/snapshot.c index bf5c2ca..06b1185 100644 --- a/block/snapshot.c +++ b/block/snapshot.c @@ -27,6 +27,7 @@ #include "block/block_int.h" #include "qapi/error.h" #include "qapi/qmp/qerror.h" +#include "qapi/qmp/qstring.h" QemuOptsList internal_snapshot_opts = { .name = "snapshot", @@ -189,14 +190,33 @@ int bdrv_snapshot_goto(BlockDriverState *bs, } if (bs->file) { + BlockDriverState *file; + QDict *options = qdict_clone_shallow(bs->options); + QDict *file_options; + + file = bs->file->bs; + /* Prevent it from getting deleted when detached from bs */ + bdrv_ref(file); + + qdict_extract_subqdict(options, &file_options, "file."); + QDECREF(file_options); + qdict_put(options, "file", qstring_from_str(bdrv_get_node_name(file))); + drv->bdrv_close(bs); - ret = bdrv_snapshot_goto(bs->file->bs, snapshot_id); - open_ret = drv->bdrv_open(bs, NULL, bs->open_flags, NULL); + bdrv_unref_child(bs, bs->file); + bs->file = NULL; + + ret = bdrv_snapshot_goto(file, snapshot_id); + open_ret = drv->bdrv_open(bs, options, bs->open_flags, NULL); + QDECREF(options); if (open_ret < 0) { - bdrv_unref(bs->file->bs); + bdrv_unref(file); bs->drv = NULL; return open_ret; } + + assert(bs->file->bs == file); + bdrv_unref(file); return ret; } |