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Commit abbbdf12 authored by Ratna Manoj Bolla's avatar Ratna Manoj Bolla Committed by Jens Axboe
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nbd: replace kill_bdev() with __invalidate_device() 



When a filesystem is mounted on a nbd device and on a disconnect, because
of kill_bdev(), and resetting bdev size to zero, buffer_head mappings are
getting destroyed under mounted filesystem.

After a bdev size reset(i.e bdev->bd_inode->i_size = 0) on a disconnect,
followed by a sys_umount(),
        generic_shutdown_super()->...
        ->__sync_blockdev()->...
        -blkdev_writepages()->...
        ->do_invalidatepage()->...
        -discard_buffer()   is discarding superblock buffer_head assumed
to be in mapped state by ext4_commit_super().

[mlin: ported to 4.11-rc2]
Signed-off-by: default avatarRatna Manoj Bolla <manoj.br@gmail.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent f8586855

drivers/block/nbd.c

+6 −2
Original line number Diff line number Diff line
@@ -126,6 +126,7 @@ static const char *nbdcmd_to_ascii(int cmd) 


static int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev)

{

	if (bdev->bd_openers <= 1)

		bd_set_size(bdev, 0);

	set_capacity(nbd->disk, 0);

	kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
@@ -665,6 +666,8 @@ static void nbd_reset(struct nbd_device *nbd) 


static void nbd_bdev_reset(struct block_device *bdev)

{

	if (bdev->bd_openers > 1)

		return;

	set_device_ro(bdev, false);

	bdev->bd_inode->i_size = 0;

	if (max_part > 0) {
@@ -728,7 +731,8 @@ static int nbd_clear_sock(struct nbd_device *nbd, struct block_device *bdev) 
{

	sock_shutdown(nbd);

	nbd_clear_que(nbd);

	kill_bdev(bdev);



	__invalidate_device(bdev, true);

	nbd_bdev_reset(bdev);

	/*

	 * We want to give the run thread a chance to wait for everybody