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[Qemu-devel] [PATCH for-2.10 2/9] block: do not set BDS read_only if cop
From: |
Jeff Cody |
Subject: |
[Qemu-devel] [PATCH for-2.10 2/9] block: do not set BDS read_only if copy_on_read enabled |
Date: |
Wed, 5 Apr 2017 14:28:44 -0400 |
A few block drivers will set the BDS read_only flag from their
.bdrv_open() function. This means the bs->read_only flag could
be set after we enable copy_on_read, as the BDRV_O_COPY_ON_READ
flag check occurs prior to the call to bdrv->bdrv_open().
This adds an error return to bdrv_set_read_only(), and an error will be
return if we try to set the BDS to read_only while copy_on_read is
enabled.
Signed-off-by: Jeff Cody <address@hidden>
---
block.c | 10 +++++++++-
block/bochs.c | 5 ++++-
block/cloop.c | 5 ++++-
block/dmg.c | 6 +++++-
block/rbd.c | 6 +++++-
block/vvfat.c | 15 ++++++++++++---
include/block/block.h | 2 +-
7 files changed, 40 insertions(+), 9 deletions(-)
diff --git a/block.c b/block.c
index 7b4c7ef..f60d5ea 100644
--- a/block.c
+++ b/block.c
@@ -192,9 +192,17 @@ void path_combine(char *dest, int dest_size,
}
}
-void bdrv_set_read_only(BlockDriverState *bs, bool read_only)
+int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
{
+ /* Do not set read_only if copy_on_read is enabled */
+ if (bs->copy_on_read && read_only) {
+ error_setg(errp, "Cannot set node '%s' to r/o while COW enabled",
+ bdrv_get_device_or_node_name(bs));
+ return -EINVAL;
+ }
+
bs->read_only = read_only;
+ return 0;
}
void bdrv_get_full_backing_filename_from_filename(const char *backed,
diff --git a/block/bochs.c b/block/bochs.c
index bdc2831..a759b6e 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -110,7 +110,10 @@ static int bochs_open(BlockDriverState *bs, QDict
*options, int flags,
return -EINVAL;
}
- bdrv_set_read_only(bs, true); /* no write support yet */
+ ret = bdrv_set_read_only(bs, true, errp); /* no write support yet */
+ if (ret < 0) {
+ return ret;
+ }
ret = bdrv_pread(bs->file, 0, &bochs, sizeof(bochs));
if (ret < 0) {
diff --git a/block/cloop.c b/block/cloop.c
index 11f17c8..d6597fc 100644
--- a/block/cloop.c
+++ b/block/cloop.c
@@ -72,7 +72,10 @@ static int cloop_open(BlockDriverState *bs, QDict *options,
int flags,
return -EINVAL;
}
- bdrv_set_read_only(bs, true);
+ ret = bdrv_set_read_only(bs, true, errp);
+ if (ret < 0) {
+ return ret;
+ }
/* read header */
ret = bdrv_pread(bs->file, 128, &s->block_size, 4);
diff --git a/block/dmg.c b/block/dmg.c
index 27ce4a6..900ae5a 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -419,8 +419,12 @@ static int dmg_open(BlockDriverState *bs, QDict *options,
int flags,
return -EINVAL;
}
+ ret = bdrv_set_read_only(bs, true, errp);
+ if (ret < 0) {
+ return ret;
+ }
+
block_module_load_one("dmg-bz2");
- bdrv_set_read_only(bs, true);
s->n_chunks = 0;
s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
diff --git a/block/rbd.c b/block/rbd.c
index 6ad2904..328e4a9 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -641,7 +641,11 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict
*options, int flags,
goto failed_open;
}
- bdrv_set_read_only(bs, (s->snap != NULL));
+ r = bdrv_set_read_only(bs, (s->snap != NULL), &local_err);
+ if (r < 0) {
+ error_propagate(errp, local_err);
+ goto failed_open;
+ }
qemu_opts_del(opts);
return 0;
diff --git a/block/vvfat.c b/block/vvfat.c
index d4ce6d7..34a2854 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -1156,8 +1156,6 @@ static int vvfat_open(BlockDriverState *bs, QDict
*options, int flags,
s->current_cluster=0xffffffff;
- /* read only is the default for safety */
- bdrv_set_read_only(bs, true);
s->qcow = NULL;
s->qcow_filename = NULL;
s->fat2 = NULL;
@@ -1173,7 +1171,18 @@ static int vvfat_open(BlockDriverState *bs, QDict
*options, int flags,
if (ret < 0) {
goto fail;
}
- bdrv_set_read_only(bs, false);
+ ret = bdrv_set_read_only(bs, false, &local_err);
+ if (ret < 0) {
+ error_propagate(errp, local_err);
+ goto fail;
+ }
+ } else {
+ /* read only is the default for safety */
+ ret = bdrv_set_read_only(bs, true, &local_err);
+ if (ret < 0) {
+ error_propagate(errp, local_err);
+ goto fail;
+ }
}
bs->total_sectors = cyls * heads * secs;
diff --git a/include/block/block.h b/include/block/block.h
index 06c9032..beb563a 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -426,7 +426,7 @@ int bdrv_is_allocated_above(BlockDriverState *top,
BlockDriverState *base,
int64_t sector_num, int nb_sectors, int *pnum);
bool bdrv_is_read_only(BlockDriverState *bs);
-void bdrv_set_read_only(BlockDriverState *bs, bool read_only);
+int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
bool bdrv_is_sg(BlockDriverState *bs);
bool bdrv_is_inserted(BlockDriverState *bs);
int bdrv_media_changed(BlockDriverState *bs);
--
2.9.3
- [Qemu-devel] [PATCH for-2.10 1/9] block: add bdrv_set_read_only() helper function, (continued)
[Qemu-devel] [PATCH for-2.10 4/9] block: code movement, Jeff Cody, 2017/04/05
[Qemu-devel] [PATCH for-2.10 2/9] block: do not set BDS read_only if copy_on_read enabled,
Jeff Cody <=
[Qemu-devel] [PATCH for-2.10 5/9] block: introduce bdrv_try_set_read_only(), Jeff Cody, 2017/04/05
[Qemu-devel] [PATCH for-2.10 6/9] block: use bdrv_try_set_read_only() during reopen, Jeff Cody, 2017/04/05