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floppy: reintroduce O_NDELAY fix 

commit 8a0c014cd20516ade9654fc13b51345ec58e7be8 upstream.

This issue was originally fixed in 09954bad4 ("floppy: refactor open()
flags handling").

The fix as a side-effect, however, introduce issue for open(O_ACCMODE)
that is being used for ioctl-only open. I wrote a fix for that, but
instead of it being merged, full revert of 09954bad4 was performed,
re-introducing the O_NDELAY / O_NONBLOCK issue, and it strikes again.

This is a forward-port of the original fix to current codebase; the
original submission 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.

Link: https://lore.kernel.org/r/nycvar.YFH.7.76.2101221209060.5622@cbobk.fhfr.pm
Cc: stable@vger.kernel.org
Reported-by: Wim Osterholt <wim@djo.tudelft.nl>
Tested-by: Wim Osterholt <wim@djo.tudelft.nl>
Reported-and-tested-by: Kurt Garloff <kurt@garloff.de>
Fixes: 09954bad4 ("floppy: refactor open() flags handling")
Fixes: f2791e7ead ("Revert "floppy: refactor open() flags handling"")
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Kosina 2021-01-22 12:13:20 +01:00 committed by Greg Kroah-Hartman
parent 337bba09d8
commit d4a7d6c022
1 changed files with 14 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
drivers/block/floppy.c
View File

@ -4063,21 +4063,22 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
if (UFDCS->rawcmd == 1)
UFDCS->rawcmd = 2;
if (!(mode & FMODE_NDELAY)) {
if (mode & (FMODE_READ|FMODE_WRITE)) {
UDRS->last_checked = 0;
clear_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags);
check_disk_change(bdev);
if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags))
goto out;
if (test_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags))
goto out;
}
res = -EROFS;
if ((mode & FMODE_WRITE) &&
!test_bit(FD_DISK_WRITABLE_BIT, &UDRS->flags))
if (mode & (FMODE_READ|FMODE_WRITE)) {
UDRS->last_checked = 0;
clear_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags);
check_disk_change(bdev);
if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags))
goto out;
if (test_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags))
goto out;
}
res = -EROFS;
if ((mode & FMODE_WRITE) &&
!test_bit(FD_DISK_WRITABLE_BIT, &UDRS->flags))
goto out;
mutex_unlock(&open_lock);
mutex_unlock(&floppy_mutex);
return 0;