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[Qemu-devel] [PATCH 23/23] block: Fix direct use of protocols as driver
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH 23/23] block: Fix direct use of protocols as driver for bdrv_open() |
Date: |
Thu, 28 Mar 2013 17:40:37 +0100 |
From: Kevin Wolf <address@hidden>
bdrv_open_common() implements direct use of protocols by copying the
pre-opened BlockDriverStates to bs using bdrv_swap(). It did however
first set some fields in bs, which end up in file after the swap. When
bdrv_open() destroys file, it appears to be open, and because it isn't,
qemu could segfault while trying to close it.
Reorder the operations to return immediately in such cases so that file
is correctly detected as closed.
Signed-off-by: Kevin Wolf <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)
diff --git a/block.c b/block.c
index 16a92a4..0ae2e93 100644
--- a/block.c
+++ b/block.c
@@ -680,6 +680,18 @@ static int bdrv_open_common(BlockDriverState *bs,
BlockDriverState *file,
trace_bdrv_open_common(bs, filename, flags, drv->format_name);
+ if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv)) {
+ return -ENOTSUP;
+ }
+
+ /* bdrv_open() with directly using a protocol as drv. This layer is already
+ * opened, so assign it to bs (while file becomes a closed
BlockDriverState)
+ * and return immediately. */
+ if (file != NULL && drv->bdrv_file_open) {
+ bdrv_swap(file, bs);
+ return 0;
+ }
+
bs->open_flags = flags;
bs->buffer_alignment = 512;
@@ -694,10 +706,6 @@ static int bdrv_open_common(BlockDriverState *bs,
BlockDriverState *file,
bs->filename[0] = '\0';
}
- if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv)) {
- return -ENOTSUP;
- }
-
bs->drv = drv;
bs->opaque = g_malloc0(drv->instance_size);
@@ -708,13 +716,9 @@ static int bdrv_open_common(BlockDriverState *bs,
BlockDriverState *file,
/* Open the image, either directly or using a protocol */
if (drv->bdrv_file_open) {
- if (file != NULL) {
- bdrv_swap(file, bs);
- ret = 0;
- } else {
- assert(drv->bdrv_parse_filename || filename != NULL);
- ret = drv->bdrv_file_open(bs, filename, options, open_flags);
- }
+ assert(file == NULL);
+ assert(drv->bdrv_parse_filename || filename != NULL);
+ ret = drv->bdrv_file_open(bs, filename, options, open_flags);
} else {
assert(file != NULL);
bs->file = file;
--
1.8.1.4
- [Qemu-devel] [PATCH 13/23] qcow2: Clean up handle_alloc(), (continued)
- [Qemu-devel] [PATCH 13/23] qcow2: Clean up handle_alloc(), Stefan Hajnoczi, 2013/03/28
- [Qemu-devel] [PATCH 14/23] qcow2: Factor out handle_copied(), Stefan Hajnoczi, 2013/03/28
- [Qemu-devel] [PATCH 15/23] qcow2: handle_copied(): Get rid of nb_clusters parameter, Stefan Hajnoczi, 2013/03/28
- [Qemu-devel] [PATCH 16/23] qcow2: handle_copied(): Get rid of keep_clusters parameter, Stefan Hajnoczi, 2013/03/28
- [Qemu-devel] [PATCH 18/23] qcow2: Prepare handle_alloc/copied() for byte granularity, Stefan Hajnoczi, 2013/03/28
- [Qemu-devel] [PATCH 17/23] qcow2: handle_copied(): Implement non-zero host_offset, Stefan Hajnoczi, 2013/03/28
- [Qemu-devel] [PATCH 19/23] qcow2: Use byte granularity in qcow2_alloc_cluster_offset(), Stefan Hajnoczi, 2013/03/28
- [Qemu-devel] [PATCH 20/23] qcow2: Allow requests with multiple l2metas, Stefan Hajnoczi, 2013/03/28
- [Qemu-devel] [PATCH 21/23] qcow2: Move cluster gathering to a non-looping loop, Stefan Hajnoczi, 2013/03/28
- [Qemu-devel] [PATCH 22/23] qcow2: Gather clusters in a looping loop, Stefan Hajnoczi, 2013/03/28
- [Qemu-devel] [PATCH 23/23] block: Fix direct use of protocols as driver for bdrv_open(),
Stefan Hajnoczi <=