Make zvol minor functionality more robust

Close the race window in zvol_open() to prevent removal of
zvol_state in the 'first open' code path. Move the call to
check_disk_change() under zvol_state_lock to make sure the
zvol_media_changed() and zvol_revalidate_disk() called by
check_disk_change() are invoked with positive zv_open_count.

Skip opened zvols when removing minors and set private_data
to NULL for zvols that are not in use whose minors are being
removed, to indicate to zvol_open() that the state is gone.
Skip opened zvols when renaming minors to avoid modifying
zv_name that might be in use, e.g. in zvol_ioctl().

Drop zvol_state_lock before calling add_disk() when creating
minors to avoid deadlocks with zvol_open().

Wrap dmu_objset_find() with spl_fstran_mark()/unmark().

Signed-off-by: Boris Protopopov <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: Richard Yao <[email protected]>
Closes #4344

0 files changed, 0 insertions, 0 deletions