Here's the 4th version of my patch to "fix" the floppy driver which
got broken by the 2.5.13-2.5.19 and 2.5.28 block dev changes.
In 2.5.28 there was a change in fs/block_dev.c which set the
floppy block dev's size to 0, and this causes ENOSPC errors on writes
to the floppy dev. This 4th version of the patch adds a workaround
for this problem.
Partial VFS access _may_ work now. I created an ext2 fs on /dev/fd0
under 2.5.28+this patch, and it fsck'd ok under both 2.5.28 and
2.4.19rc3. However, when I attempted to put lilo on that floppy
the kernel oopsed with a "buffer layer error at buffer.c:403", so
things are still not quite right.
/Mikael
diff -ruN linux-2.5.28/drivers/block/floppy.c linux-2.5.28.fix-floppy/drivers/block/floppy.c
--- linux-2.5.28/drivers/block/floppy.c Thu Jul 25 01:27:30 2002
+++ linux-2.5.28.fix-floppy/drivers/block/floppy.c Thu Jul 25 14:33:49 2002
@@ -3699,6 +3699,10 @@
UDRS->fd_ref = 0;
}
floppy_release_irq_and_dma();
+
+ /* undo ++bd_openers in floppy_open() */
+ --inode->i_bdev->bd_openers;
+
return 0;
}
@@ -3791,6 +3795,43 @@
invalidate_buffers(mk_kdev(FLOPPY_MAJOR,old_dev));
}
+ /* Problems:
+ * 1. floppy_open() triggers a call to submit_bio(), but
+ * bdev->bd_queue may be NULL since it is not set up until
+ * after floppy_open() has returned. Prior to 2.5.18, NULL
+ * queues were initialised when needed.
+ * 2. fs/block_dev.c:do_open() changes bdev's block size
+ * after floppy_open() has returned. For some reason, this
+ * causes data corruption durings writes.
+ * 3. fs/block_dev.c:do_open() sets bdev->bd_inode->i_size to 0
+ * after floppy_open() has returned. This cases ENOSPC errors
+ * on writes.
+ * Workarounds:
+ * 1. bdev->bd_queue is initialised here.
+ * 2. Set bdev block size equal to the hardsect/queue size.
+ * This seems to cure the data corruption problem for raw
+ * accesses. VFS accesses to mounted floppies still cause
+ * data corruption for unknown reasons.
+ * 3. Set i_size to 1.44M and bd_offset to 0.
+ * 2&3. ++bdev->bd_openers to bypass do_open()'s changes.
+ * floppy_release() does a --bdev->bd_openers.
+ */
+ {
+ struct block_device *bdev = inode->i_bdev;
+ kdev_t dev = inode->i_rdev;
+ struct blk_dev_struct *p = blk_dev + major(dev);
+
+ if (p->queue)
+ bdev->bd_queue = p->queue(dev);
+ else
+ bdev->bd_queue = &p->request_queue;
+ bdev->bd_block_size = bdev_hardsect_size(bdev);
+ bdev->bd_inode->i_blkbits = blksize_bits(block_size(bdev));
+ bdev->bd_offset = 0;
+ bdev->bd_inode->i_size = 1440 * 1024;
+ ++bdev->bd_openers;
+ }
+
/* Allow ioctls if we have write-permissions even if read-only open.
* Needed so that programs such as fdrawcmd still can work on write
* protected disks */
@@ -4228,8 +4269,6 @@
{
int i,unit,drive;
- register_sys_device(&device_floppy);
-
raw_cmd = NULL;
devfs_handle = devfs_mk_dir (NULL, "floppy", NULL);
@@ -4356,6 +4395,9 @@
register_disk(NULL, mk_kdev(MAJOR_NR,TOMINOR(drive)+i*4),
1, &floppy_fops, 0);
}
+
+ register_sys_device(&device_floppy);
+
return have_no_fdc;
}
@@ -4538,6 +4580,7 @@
{
int dummy;
+ unregister_sys_device(&device_floppy);
devfs_unregister (devfs_handle);
devfs_unregister_blkdev(MAJOR_NR, "fd");
-
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This archive was generated by hypermail 2b29 : Tue Jul 30 2002 - 14:00:20 EST