From 7b7b68bba5ef23734c35ffb0d8d82079ed604d33 Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Fri, 10 Jan 2014 02:08:13 +0100 Subject: floppy: bail out in open() if drive is not responding to block0 read In case reading of block 0 during open() fails, it is not the right thing to let open() succeed. Fix this by introducing FD_OPEN_SHOULD_FAIL_BIT flag, and setting it in case the bio callback encounters an error while trying to read block 0. As a bonus, this works around certain broken userspace (blkid), which is not able to properly handle read()s returning IO errors. Hence be nice to those, and bail out during open() already; if block 0 is not readable, read()s are not going to provide any meaningful data anyway. Signed-off-by: Jiri Kosina --- drivers/block/floppy.c | 36 +++++++++++++++++++++++++++--------- 1 file changed, 27 insertions(+), 9 deletions(-) (limited to 'drivers/block/floppy.c') diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 6b29c4422828..2023043ce7c0 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3691,9 +3691,12 @@ static int floppy_open(struct block_device *bdev, fmode_t mode) 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) && @@ -3746,17 +3749,29 @@ static unsigned int floppy_check_events(struct gendisk *disk, * a disk in the drive, and whether that disk is writable. */ -static void floppy_rb0_complete(struct bio *bio, int err) +struct rb0_cbdata { + int drive; + struct completion complete; +}; + +static void floppy_rb0_cb(struct bio *bio, int err) { - complete((struct completion *)bio->bi_private); + struct rb0_cbdata *cbdata = (struct rb0_cbdata *)bio->bi_private; + int drive = cbdata->drive; + + if (err) { + pr_info("floppy: error %d while reading block 0", err); + set_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags); + } + complete(&cbdata->complete); } -static int __floppy_read_block_0(struct block_device *bdev) +static int __floppy_read_block_0(struct block_device *bdev, int drive) { struct bio bio; struct bio_vec bio_vec; - struct completion complete; struct page *page; + struct rb0_cbdata cbdata; size_t size; page = alloc_page(GFP_NOIO); @@ -3769,6 +3784,8 @@ static int __floppy_read_block_0(struct block_device *bdev) if (!size) size = 1024; + cbdata.drive = drive; + bio_init(&bio); bio.bi_io_vec = &bio_vec; bio_vec.bv_page = page; @@ -3779,13 +3796,14 @@ static int __floppy_read_block_0(struct block_device *bdev) bio.bi_bdev = bdev; bio.bi_iter.bi_sector = 0; bio.bi_flags = (1 << BIO_QUIET); - init_completion(&complete); - bio.bi_private = &complete; - bio.bi_end_io = floppy_rb0_complete; + bio.bi_private = &cbdata; + bio.bi_end_io = floppy_rb0_cb; submit_bio(READ, &bio); process_fd_request(); - wait_for_completion(&complete); + + init_completion(&cbdata.complete); + wait_for_completion(&cbdata.complete); __free_page(page); @@ -3827,7 +3845,7 @@ static int floppy_revalidate(struct gendisk *disk) UDRS->generation++; if (drive_no_geom(drive)) { /* auto-sensing */ - res = __floppy_read_block_0(opened_bdev[drive]); + res = __floppy_read_block_0(opened_bdev[drive], drive); } else { if (cf) poll_drive(false, FD_RAW_NEED_DISK); -- cgit v1.2.3