| Message ID | 1490050729-3578-2-git-send-email-mlin@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Mar 20, 2017 at 3:58 PM, Ming Lin <mlin@kernel.org> wrote: > From: Ratna Manoj Bolla <manoj.br@gmail.com> > > 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 <manoj.br@gmail.com > --- > 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 cb4ccfc..a6a3643 100644 > --- a/drivers/block/nbd.c > +++ b/drivers/block/nbd.c > @@ -125,7 +125,8 @@ 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); > > @@ -603,6 +604,8 @@ 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) { > @@ -666,7 +669,8 @@ 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 > -- > 1.8.3.1 Hi Josef, Any comments? Thanks, Ming
Hey sorry I just got back from LSF, I’ll look at this in the morning. Thanks, Josef On 3/22/17, 4:48 PM, "Ming Lin" <mlin@kernel.org> wrote: On Mon, Mar 20, 2017 at 3:58 PM, Ming Lin <mlin@kernel.org> wrote: > From: Ratna Manoj Bolla <manoj.br@gmail.com> > > 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 <manoj.br@gmail.com > --- > 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 cb4ccfc..a6a3643 100644 > --- a/drivers/block/nbd.c > +++ b/drivers/block/nbd.c > @@ -125,7 +125,8 @@ 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); > > @@ -603,6 +604,8 @@ 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) { > @@ -666,7 +669,8 @@ 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 > -- > 1.8.3.1 Hi Josef, Any comments? Thanks, Ming
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index cb4ccfc..a6a3643 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -125,7 +125,8 @@ 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); @@ -603,6 +604,8 @@ 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) { @@ -666,7 +669,8 @@ 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