Re: [PATCH RESEND] floppy: fix open(O_ACCMODE) for ioctl-only open

Jiri Kosina
2021-01-21T14:45:50Z

On Thu, 21 Jan 2021, Jiri Kosina wrote:

> I am currently waiting for confirmation by the original reporter that the
> patch below fixes the issue.

... a now a patch that actually compiles :) (made a mistake when
forward-porting from the older kernel on which this has been reported).

From: Jiri Kosina <jkosina@suse.cz>
Subject: [PATCH v2] floppy: reintroduce O_NDELAY fix

Originally fixed in 09954bad4 ("floppy: refactor open() flags handling")
then reverted for unknown reason in f2791e7eadf437 instead of taking
the open(O_ACCMODE) for ioctl-only open fix, which had the changelog below

====
Commit 09954bad4 ("floppy: refactor open() flags handling"), as a
side-effect, causes open(/dev/fdX, O_ACCMODE) to fail. It turns out that
this is being used setfdprm userspace for ioctl-only open().

Reintroduce back the original behavior wrt !(FMODE_READ|FMODE_WRITE)
modes, while still keeping the original O_NDELAY bug fixed.

Cc: stable@vger.kernel.org # v4.5+
Reported-by: Wim Osterholt <wim@djo.tudelft.nl>
Tested-by: Wim Osterholt <wim@djo.tudelft.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
=====

Fixes: 09954bad4 ("floppy: refactor open() flags handling")
Fixes: f2791e7ead ("Revert "floppy: refactor open() flags handling"")
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---

v1 -> v2: fix build issue due to bad forward-port

drivers/block/floppy.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index dfe1dfc901cc..f9e839c8c5aa 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4121,23 +4121,23 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
if (fdc_state[FDC(drive)].rawcmd == 1)
fdc_state[FDC(drive)].rawcmd = 2;

- if (!(mode & FMODE_NDELAY)) {
- if (mode & (FMODE_READ|FMODE_WRITE)) {
- drive_state[drive].last_checked = 0;
- clear_bit(FD_OPEN_SHOULD_FAIL_BIT,
- &drive_state[drive].flags);
- if (bdev_check_media_change(bdev))
- floppy_revalidate(bdev->bd_disk);
- if (test_bit(FD_DISK_CHANGED_BIT, &drive_state[drive].flags))
- goto out;
- if (test_bit(FD_OPEN_SHOULD_FAIL_BIT, &drive_state[drive].flags))
- goto out;
- }
- res = -EROFS;
- if ((mode & FMODE_WRITE) &&
- !test_bit(FD_DISK_WRITABLE_BIT, &drive_state[drive].flags))
+ if (mode & (FMODE_READ|FMODE_WRITE)) {
+ UDRS->last_checked = 0;
+ clear_bit(FD_OPEN_SHOULD_FAIL_BIT, &drive_state[drive].flags);
+ if (bdev_check_media_change(bdev))
+ floppy_revalidate(bdev->bd_disk);
+ if (test_bit(FD_DISK_CHANGED_BIT, &drive_state[drive].flags))
+ goto out;
+ if (test_bit(FD_OPEN_SHOULD_FAIL_BIT, &drive_state[drive].flags))
goto out;
}
+
+ res = -EROFS;
+
+ if ((mode & FMODE_WRITE) &&
+ !test_bit(FD_DISK_WRITABLE_BIT, &drive_state[drive].flags))
+ goto out;
+
mutex_unlock(&open_lock);
mutex_unlock(&floppy_mutex);
return 0;

--
Jiri Kosina
SUSE Labs