Attachment 573679 Details for Bug 848796

[patch] [PATCH] floppy: bail out in open() if drive is not responding

0001-floppy-bail-out-in-open-if-drive-is-not-responding.patch (text/plain), 3.16 KB, created by Jiri Kosina on 2014-01-08 11:05:57 UTC

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Creator: Jiri Kosina

Created: 2014-01-08 11:05:57 UTC

Size: 3.16 KB

patch

obsolete

>From 18eb4fec00b643a492992c2749dacae62657880e Mon Sep 17 00:00:00 2001
>From: Jiri Kosina <jkosina@suse.cz>
>Date: Wed, 8 Jan 2014 11:59:48 +0100
>Subject: [PATCH] floppy: bail out in open() if drive is not responding
>
>There are reportedly machines with BIOSes that are reporting everything
>as if the floppy drive was present on the system, except it is not.
>
>We are then sleeping long time until timeout in open(/dev/fdX). What is
>worse, the open() syscall then succeeds, as there is no way check_disk_change()
>is expected to fail.
>
>Fix this by introducing FD_DRIVE_BROKEN_BIT flag, and setting it in case the
>bio callback encounters an error while trying to read block 0.
>
>NOT-YET-Signed-off-by: Jiri Kosina <jkosina@suse.cz>
>---
> drivers/block/floppy.c  |   29 ++++++++++++++++++++++-------
> include/uapi/linux/fd.h |    3 ++-
> 2 files changed, 24 insertions(+), 8 deletions(-)
>
>diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
>index 000abe2..290be37 100644
>--- a/drivers/block/floppy.c
>+++ b/drivers/block/floppy.c
>@@ -3694,6 +3694,8 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
> 			check_disk_change(bdev);
> 			if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags))
> 				goto out;
>+			if (test_bit(FD_DRIVE_BROKEN_BIT, &UDRS->flags))
>+				goto out;
> 		}
> 		res = -EROFS;
> 		if ((mode & FMODE_WRITE) &&
>@@ -3746,17 +3748,29 @@ 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) {
>+		printk(KERN_DEBUG "floppy: error %d while reading block 0", err);
>+		set_bit(FD_DRIVE_BROKEN_BIT, &UDRS->flags);
>+	}
>+	complete(&cbdata->complete);
> }
> 
> static int __floppy_read_block_0(struct block_device *bdev)
> {
> 	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);
>@@ -3779,13 +3793,14 @@ static int __floppy_read_block_0(struct block_device *bdev)
> 	bio.bi_bdev = bdev;
> 	bio.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);
> 
>diff --git a/include/uapi/linux/fd.h b/include/uapi/linux/fd.h
>index f1f3dd5..4ec49a0 100644
>--- a/include/uapi/linux/fd.h
>+++ b/include/uapi/linux/fd.h
>@@ -185,7 +185,8 @@ enum {
> 				 * to clear media change status */
> 	FD_UNUSED_BIT,
> 	FD_DISK_CHANGED_BIT,	/* disk has been changed since last i/o */
>-	FD_DISK_WRITABLE_BIT	/* disk is writable */
>+	FD_DISK_WRITABLE_BIT,	/* disk is writable */
>+	FD_DRIVE_BROKEN_BIT
> };
> 
> #define FDSETDRVPRM _IOW(2, 0x90, struct floppy_drive_params)
>-- 
>1.7.3.1
>

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Attachments on bug 848796: 573679