ceph: fix recursion between ceph_set_acl() and __ceph_setattr()

ceph_set_acl() calls __ceph_setattr() if the setacl operation needs
to modify inode's i_mode. __ceph_setattr() updates inode's i_mode,
then calls posix_acl_chmod().

The problem is that __ceph_setattr() calls posix_acl_chmod() before
sending the setattr request. The get_acl() call in posix_acl_chmod()
can trigger a getxattr request. The reply of the getxattr request
can restore inode's i_mode to its old value. The set_acl() call in
posix_acl_chmod() sees old value of inode's i_mode, so it calls
__ceph_setattr() again.

Cc: [email protected] # needs backporting for < 4.9
Link: http://tracker.ceph.com/issues/19688
Reported-by: Jerry Lee <[email protected]>
Signed-off-by: "Yan, Zheng" <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Tested-by: Luis Henriques <[email protected]>
Signed-off-by: Ilya Dryomov <[email protected]>

0 files changed, 0 insertions, 0 deletions