From: Jiri Kosina jkosina@suse.cz
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
--- drivers/block/floppy.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-)
--- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -4066,21 +4066,22 @@ static int floppy_open(struct block_devi 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;