gfs2: annotate i_gl with __rcu

ip->i_gl is always set over the lifetime of a gfs2 inode; it is
initialized at inode create time and torn down during evict.

However, gfs2_permission() can be called on an inode in non-blocking
mode, when the inode may already be undergoing evict.  So far, to make
that work, we have been using rcu_dereference_check() in
gfs2_permission() and rcu_assign_pointer() in gfs2_evict_inode().

However, ip->i_gl wasn't marked as __rcu so far.
rcu_dereference_check() and rcu_assign_pointer() expect __rcu pointer
arguments, and sparse complains when regular pointers are passed to
those functions:

fs/gfs2/super.c:1516:17: error: incompatible types in comparison expression (different address spaces):
fs/gfs2/super.c:1516:17:    struct gfs2_glock [noderef] __rcu *
fs/gfs2/super.c:1516:17:    struct gfs2_glock *
fs/gfs2/inode.c:1988:14: error: incompatible types in comparison expression (different address spaces):
fs/gfs2/inode.c:1988:14:    struct gfs2_glock [noderef] __rcu *
fs/gfs2/inode.c:1988:14:    struct gfs2_glock *

To fix those errors, turn ip->i_gl into a __rcu variable.  Use
rcu_assign_pointer() to assign to it, and rcu_dereference_protected() to
access it when the pointer is known to be valid.

Make sure not to use gfs2_inode_glock() in gfs2_permission().

Based on a patch from Adrian Garcia Casado <adriangarciacasado42@gmail.com>.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

0 files changed, 0 insertions, 0 deletions