From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: From: Josef Bacik To: axboe@kernel.dk, nbd-general@lists.sourceforge.net, linux-block@vger.kernel.org, kernel-team@fb.com Cc: Ratna Manoj Bolla Subject: [PATCH 4/4] nbd: replace kill_bdev() with __invalidate_device() Date: Fri, 24 Mar 2017 14:08:29 -0400 Message-Id: <1490378909-4056-5-git-send-email-josef@toxicpanda.com> In-Reply-To: <1490378909-4056-1-git-send-email-josef@toxicpanda.com> References: <1490378909-4056-1-git-send-email-josef@toxicpanda.com> List-ID: From: Ratna Manoj Bolla 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: Ratna Manoj Bolla --- drivers/block/nbd.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index b0003da..d8a2356 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -126,7 +126,8 @@ static const char *nbdcmd_to_ascii(int cmd) static int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev) { - bd_set_size(bdev, 0); + 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 -- 2.7.4