@@ -401,7 +401,7 @@ static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp)
}
}
-static int check_hdev_writable(BDRVRawState *s)
+static int check_hdev_writable(int fd)
{
#if defined(BLKROGET)
/* Linux block devices can be configured "read-only" using blockdev(8).
@@ -415,7 +415,7 @@ static int check_hdev_writable(BDRVRawState *s)
struct stat st;
int readonly = 0;
- if (fstat(s->fd, &st)) {
+ if (fstat(fd, &st)) {
return -errno;
}
@@ -423,7 +423,7 @@ static int check_hdev_writable(BDRVRawState *s)
return 0;
}
- if (ioctl(s->fd, BLKROGET, &readonly) < 0) {
+ if (ioctl(fd, BLKROGET, &readonly) < 0) {
return -errno;
}
@@ -618,6 +618,15 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
}
s->fd = fd;
+ /* Check s->open_flags rather than bdrv_flags due to auto-read-only */
+ if (s->open_flags & O_RDWR) {
+ ret = check_hdev_writable(s->fd);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "The device is not writable");
+ goto fail;
+ }
+ }
+
s->perm = 0;
s->shared_perm = BLK_PERM_ALL;
@@ -1010,6 +1019,15 @@ static int raw_reconfigure_getfd(BlockDriverState *bs, int flags,
}
}
+ if (fd != -1 && (*open_flags & O_RDWR)) {
+ ret = check_hdev_writable(fd);
+ if (ret < 0) {
+ qemu_close(fd);
+ error_setg_errno(errp, -ret, "The device is not writable");
+ return -1;
+ }
+ }
+
return fd;
}
@@ -3454,15 +3472,6 @@ hdev_open_Mac_error:
/* Since this does ioctl the device must be already opened */
bs->sg = hdev_is_sg(bs);
- if (flags & BDRV_O_RDWR) {
- ret = check_hdev_writable(s);
- if (ret < 0) {
- raw_close(bs);
- error_setg_errno(errp, -ret, "The device is not writable");
- return ret;
- }
- }
-
return ret;
}
For Linux block devices, being able to open the device read-write doesn't necessarily mean that the device is actually writable (one example is a read-only LV, as you get with lvchange -pr <device>). We have check_hdev_writable() to check this condition and fail opening the image read-write if it's not actually writable. However, this check doesn't take auto-read-only into account, but results in a hard failure instead of downgrading to read-only where possible. Fix this and do the writable check not based on BDRV_O_RDWR, but only when this actually results in opening the file read-write. A second check is inserted in raw_reconfigure_getfd() to have the same check when dynamic auto-read-only upgrades an image file from read-only to read-write. Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/file-posix.c | 33 +++++++++++++++++++++------------ 1 file changed, 21 insertions(+), 12 deletions(-)