1 From 48f550221420bd90ddca06c6c7492ea3aca9b644 Mon Sep 17 00:00:00 2001
2 From: Jeff Cody <jcody@redhat.com>
3 Date: Thu, 20 Sep 2012 15:13:17 -0400
4 Subject: [PATCH] block: correctly set the keep_read_only flag
6 I believe the bs->keep_read_only flag is supposed to reflect
7 the initial open state of the device. If the device is initially
8 opened R/O, then commit operations, or reopen operations changing
9 to R/W, are prohibited.
11 Currently, the keep_read_only flag is only accurate for the active
12 layer, and its backing file. Subsequent images end up always having
13 the keep_read_only flag set.
15 For instance, what happens now:
17 [ base ] kro = 1, ro = 1
20 [ snap-1 ] kro = 1, ro = 1
23 [ snap-2 ] kro = 0, ro = 1
26 [ active ] kro = 0, ro = 0
30 [ base ] kro = 0, ro = 1
33 [ snap-1 ] kro = 0, ro = 1
36 [ snap-2 ] kro = 0, ro = 1
39 [ active ] kro = 0, ro = 0
41 Signed-off-by: Jeff Cody <jcody@redhat.com>
42 Signed-off-by: Kevin Wolf <kwolf@redhat.com>
43 (cherry picked from commit be028adcedd68ca4d78fdc43e7e2fa4f1cdbc653)
45 Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
47 block.c | 14 +++++++-------
49 2 files changed, 8 insertions(+), 7 deletions(-)
51 diff --git a/block.c b/block.c
52 index e78039b..4c0e7f5 100644
55 @@ -668,7 +668,7 @@ static int bdrv_open_common(BlockDriverState *bs, const char *filename,
56 open_flags |= BDRV_O_RDWR;
59 - bs->keep_read_only = bs->read_only = !(open_flags & BDRV_O_RDWR);
60 + bs->read_only = !(open_flags & BDRV_O_RDWR);
62 /* Open the image, either directly or using a protocol */
63 if (drv->bdrv_file_open) {
64 @@ -808,6 +808,12 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
68 + if (flags & BDRV_O_RDWR) {
69 + flags |= BDRV_O_ALLOW_RDWR;
72 + bs->keep_read_only = !(flags & BDRV_O_ALLOW_RDWR);
75 ret = bdrv_open_common(bs, filename, flags, drv);
77 @@ -837,12 +843,6 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
81 - if (bs->is_temporary) {
82 - bs->backing_hd->keep_read_only = !(flags & BDRV_O_RDWR);
84 - /* base image inherits from "parent" */
85 - bs->backing_hd->keep_read_only = bs->keep_read_only;
89 if (!bdrv_key_required(bs)) {
90 diff --git a/block.h b/block.h
91 index 2e2be11..4d919c2 100644
94 @@ -80,6 +80,7 @@ typedef struct BlockDevOps {
95 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
96 #define BDRV_O_INCOMING 0x0800 /* consistency hint for incoming migration */
97 #define BDRV_O_CHECK 0x1000 /* open solely for consistency check */
98 +#define BDRV_O_ALLOW_RDWR 0x2000 /* allow reopen to change from r/o to r/w */
100 #define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH)