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[PULL 11/12] file-posix: Fix check_hdev_writable() with auto-read-only
From: |
Kevin Wolf |
Subject: |
[PULL 11/12] file-posix: Fix check_hdev_writable() with auto-read-only |
Date: |
Fri, 17 Jul 2020 14:55:09 +0200 |
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>
Message-Id: <20200717105426.51134-3-kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block/file-posix.c | 33 +++++++++++++++++++++------------
1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/block/file-posix.c b/block/file-posix.c
index dd7dab07d6..996e45ab95 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -425,7 +425,7 @@ 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).
@@ -439,7 +439,7 @@ static int check_hdev_writable(BDRVRawState *s)
struct stat st;
int readonly = 0;
- if (fstat(s->fd, &st)) {
+ if (fstat(fd, &st)) {
return -errno;
}
@@ -447,7 +447,7 @@ static int check_hdev_writable(BDRVRawState *s)
return 0;
}
- if (ioctl(s->fd, BLKROGET, &readonly) < 0) {
+ if (ioctl(fd, BLKROGET, &readonly) < 0) {
return -errno;
}
@@ -642,6 +642,15 @@ 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;
@@ -1034,6 +1043,15 @@ 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;
}
@@ -3478,15 +3496,6 @@ 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;
}
--
2.25.4
- [PULL 01/12] vvfat: set status to odd fixes, (continued)
- [PULL 01/12] vvfat: set status to odd fixes, Kevin Wolf, 2020/07/17
- [PULL 03/12] qemu-img resize: Require --shrink for shrinking all image formats, Kevin Wolf, 2020/07/17
- [PULL 05/12] iotests/030: Reduce job speed to make race less likely, Kevin Wolf, 2020/07/17
- [PULL 02/12] Remove VXHS block device, Kevin Wolf, 2020/07/17
- [PULL 06/12] nbd: make nbd_export_close_all() synchronous, Kevin Wolf, 2020/07/17
- [PULL 04/12] crypto: use a stronger private key for tests, Kevin Wolf, 2020/07/17
- [PULL 08/12] block: Require aligned image size to avoid assertion failure, Kevin Wolf, 2020/07/17
- [PULL 09/12] file-posix: Allow byte-aligned O_DIRECT with NFS, Kevin Wolf, 2020/07/17
- [PULL 07/12] iotests: test shutdown when bitmap is exported through NBD, Kevin Wolf, 2020/07/17
- [PULL 10/12] file-posix: Move check_hdev_writable() up, Kevin Wolf, 2020/07/17
- [PULL 11/12] file-posix: Fix check_hdev_writable() with auto-read-only,
Kevin Wolf <=
- [PULL 12/12] file-posix: Fix leaked fd in raw_open_common() error path, Kevin Wolf, 2020/07/17
- Re: [PULL 00/12] Block layer patches for 5.1.0-rc1, Peter Maydell, 2020/07/18