Implement new world order in VFS locking for extended attributes. This will

remove the unconditional acquisition of Giant for extended attribute related
operations. If the file system is set as being MP safe and debug.mpsafevfs is
1, do not pickup Giant.

Mark the following system calls as being MP safe so we no longer pickup Giant
in the system call handler:

o extattrctl
o extattr_set_file
o extattr_get_file
o extattr_delete_file
o extattr_set_fd
o extattr_get_fd
o extattr_delete_fd
o extattr_set_link
o extattr_get_link
o extattr_delete_link
o extattr_list_file
o extattr_list_link
o extattr_list_fd

-Pass MPSAFE flags to namei(9) lookup and introduce vfslocked variable which
 will keep track of any Giant acquisitions.
-Wrap any fd operations which manipulate vnodes in VFS_{UN}LOCK_GIANT
-Drop VFS_ASSERT_GIANT into function which operate on vnodes to ensure that
 we are sufficiently protected.

I've tested these changes with various TrustedBSD MAC policies which use
extended attribute a lot on SMP and UP systems (thanks to Scott Long for
making some SMP hardware available to me for testing).

Discussed with:	jeff
Requested by:	jhb, rwatson

1 files changed, 13 insertions, 13 deletions

diff --git a/sys/kern/init_sysent.c b/sys/kern/init_sysent.c
index e67baf2..03a0d6e 100644
--- a/sys/kern/init_sysent.c
+++ b/sys/kern/init_sysent.c
@@ -384,10 +384,10 @@ struct sysent sysent[] = {
 	{ SYF_MPSAFE | AS(__acl_delete_fd_args), (sy_call_t *)__acl_delete_fd, AUE_NULL },	/* 352 = __acl_delete_fd */
 	{ SYF_MPSAFE | AS(__acl_aclcheck_file_args), (sy_call_t *)__acl_aclcheck_file, AUE_NULL },	/* 353 = __acl_aclcheck_file */
 	{ SYF_MPSAFE | AS(__acl_aclcheck_fd_args), (sy_call_t *)__acl_aclcheck_fd, AUE_NULL },	/* 354 = __acl_aclcheck_fd */
-	{ AS(extattrctl_args), (sy_call_t *)extattrctl, AUE_NULL },	/* 355 = extattrctl */
-	{ AS(extattr_set_file_args), (sy_call_t *)extattr_set_file, AUE_NULL },	/* 356 = extattr_set_file */
-	{ AS(extattr_get_file_args), (sy_call_t *)extattr_get_file, AUE_NULL },	/* 357 = extattr_get_file */
-	{ AS(extattr_delete_file_args), (sy_call_t *)extattr_delete_file, AUE_NULL },	/* 358 = extattr_delete_file */
+	{ SYF_MPSAFE | AS(extattrctl_args), (sy_call_t *)extattrctl, AUE_NULL },	/* 355 = extattrctl */
+	{ SYF_MPSAFE | AS(extattr_set_file_args), (sy_call_t *)extattr_set_file, AUE_NULL },	/* 356 = extattr_set_file */
+	{ SYF_MPSAFE | AS(extattr_get_file_args), (sy_call_t *)extattr_get_file, AUE_NULL },	/* 357 = extattr_get_file */
+	{ SYF_MPSAFE | AS(extattr_delete_file_args), (sy_call_t *)extattr_delete_file, AUE_NULL },	/* 358 = extattr_delete_file */
 	{ AS(aio_waitcomplete_args), (sy_call_t *)lkmressys, AUE_NULL },	/* 359 = aio_waitcomplete */
 	{ SYF_MPSAFE | AS(getresuid_args), (sy_call_t *)getresuid, AUE_NULL },	/* 360 = getresuid */
 	{ SYF_MPSAFE | AS(getresgid_args), (sy_call_t *)getresgid, AUE_NULL },	/* 361 = getresgid */
@@ -400,9 +400,9 @@ struct sysent sysent[] = {
 	{ 0, (sy_call_t *)nosys, AUE_NULL },			/* 368 = __cap_set_fd */
 	{ 0, (sy_call_t *)nosys, AUE_NULL },			/* 369 = __cap_set_file */
 	{ AS(nosys_args), (sy_call_t *)lkmressys, AUE_NULL },	/* 370 = lkmressys */
-	{ AS(extattr_set_fd_args), (sy_call_t *)extattr_set_fd, AUE_NULL },	/* 371 = extattr_set_fd */
-	{ AS(extattr_get_fd_args), (sy_call_t *)extattr_get_fd, AUE_NULL },	/* 372 = extattr_get_fd */
-	{ AS(extattr_delete_fd_args), (sy_call_t *)extattr_delete_fd, AUE_NULL },	/* 373 = extattr_delete_fd */
+	{ SYF_MPSAFE | AS(extattr_set_fd_args), (sy_call_t *)extattr_set_fd, AUE_NULL },	/* 371 = extattr_set_fd */
+	{ SYF_MPSAFE | AS(extattr_get_fd_args), (sy_call_t *)extattr_get_fd, AUE_NULL },	/* 372 = extattr_get_fd */
+	{ SYF_MPSAFE | AS(extattr_delete_fd_args), (sy_call_t *)extattr_delete_fd, AUE_NULL },	/* 373 = extattr_delete_fd */
 	{ SYF_MPSAFE | AS(__setugid_args), (sy_call_t *)__setugid, AUE_NULL },	/* 374 = __setugid */
 	{ AS(nfsclnt_args), (sy_call_t *)nosys, AUE_NULL },	/* 375 = nfsclnt */
 	{ SYF_MPSAFE | AS(eaccess_args), (sy_call_t *)eaccess, AUE_NULL },	/* 376 = eaccess */
@@ -441,9 +441,9 @@ struct sysent sysent[] = {
 	{ SYF_MPSAFE | AS(__mac_get_pid_args), (sy_call_t *)__mac_get_pid, AUE_NULL },	/* 409 = __mac_get_pid */
 	{ SYF_MPSAFE | AS(__mac_get_link_args), (sy_call_t *)__mac_get_link, AUE_NULL },	/* 410 = __mac_get_link */
 	{ SYF_MPSAFE | AS(__mac_set_link_args), (sy_call_t *)__mac_set_link, AUE_NULL },	/* 411 = __mac_set_link */
-	{ AS(extattr_set_link_args), (sy_call_t *)extattr_set_link, AUE_NULL },	/* 412 = extattr_set_link */
-	{ AS(extattr_get_link_args), (sy_call_t *)extattr_get_link, AUE_NULL },	/* 413 = extattr_get_link */
-	{ AS(extattr_delete_link_args), (sy_call_t *)extattr_delete_link, AUE_NULL },	/* 414 = extattr_delete_link */
+	{ SYF_MPSAFE | AS(extattr_set_link_args), (sy_call_t *)extattr_set_link, AUE_NULL },	/* 412 = extattr_set_link */
+	{ SYF_MPSAFE | AS(extattr_get_link_args), (sy_call_t *)extattr_get_link, AUE_NULL },	/* 413 = extattr_get_link */
+	{ SYF_MPSAFE | AS(extattr_delete_link_args), (sy_call_t *)extattr_delete_link, AUE_NULL },	/* 414 = extattr_delete_link */
 	{ SYF_MPSAFE | AS(__mac_execve_args), (sy_call_t *)__mac_execve, AUE_NULL },	/* 415 = __mac_execve */
 	{ SYF_MPSAFE | AS(sigaction_args), (sy_call_t *)sigaction, AUE_NULL },	/* 416 = sigaction */
 	{ SYF_MPSAFE | AS(sigreturn_args), (sy_call_t *)sigreturn, AUE_NULL },	/* 417 = sigreturn */
@@ -466,9 +466,9 @@ struct sysent sysent[] = {
 	{ SYF_MPSAFE | AS(_umtx_lock_args), (sy_call_t *)_umtx_lock, AUE_NULL },	/* 434 = _umtx_lock */
 	{ SYF_MPSAFE | AS(_umtx_unlock_args), (sy_call_t *)_umtx_unlock, AUE_NULL },	/* 435 = _umtx_unlock */
 	{ SYF_MPSAFE | AS(jail_attach_args), (sy_call_t *)jail_attach, AUE_NULL },	/* 436 = jail_attach */
-	{ AS(extattr_list_fd_args), (sy_call_t *)extattr_list_fd, AUE_NULL },	/* 437 = extattr_list_fd */
-	{ AS(extattr_list_file_args), (sy_call_t *)extattr_list_file, AUE_NULL },	/* 438 = extattr_list_file */
-	{ AS(extattr_list_link_args), (sy_call_t *)extattr_list_link, AUE_NULL },	/* 439 = extattr_list_link */
+	{ SYF_MPSAFE | AS(extattr_list_fd_args), (sy_call_t *)extattr_list_fd, AUE_NULL },	/* 437 = extattr_list_fd */
+	{ SYF_MPSAFE | AS(extattr_list_file_args), (sy_call_t *)extattr_list_file, AUE_NULL },	/* 438 = extattr_list_file */
+	{ SYF_MPSAFE | AS(extattr_list_link_args), (sy_call_t *)extattr_list_link, AUE_NULL },	/* 439 = extattr_list_link */
 	{ SYF_MPSAFE | AS(kse_switchin_args), (sy_call_t *)kse_switchin, AUE_NULL },	/* 440 = kse_switchin */
 	{ SYF_MPSAFE | AS(ksem_timedwait_args), (sy_call_t *)lkmressys, AUE_NULL },	/* 441 = ksem_timedwait */
 	{ SYF_MPSAFE | AS(thr_suspend_args), (sy_call_t *)thr_suspend, AUE_NULL },	/* 442 = thr_suspend */