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DEBUG_VFS_LOCKS: stop excluding devfs and doomed vnode from asserts

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We do not require devvp vnode locked for metadata io.  It is typically
not needed indeed, since correctness of the file system using
corresponding block device ensures that there is no incorrect or racy
manipulations.

But right now DEBUG_VFS_LOCKS option excludes both character device
vnodes and completely destroyed (VBAD) vnodes from asserts.  This is not
too bad since WITNESS still ensures that we do not leak locks.  On the
other hand, asserts do not mean what they should, to the reader, and
reliance on them being enforced might result in wrong code.

Note that ASSERT_VOP_LOCKED() still silently accepts NULLVP, I think it
is worth fixing as well, in the next round.

In collaboration with:	pho
Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Differential revision:	https://reviews.freebsd.org/D32761
This commit is contained in:
Konstantin Belousov 2021-10-31 23:34:57 +02:00
parent 47b248ac65
commit d032cda0d0
1 changed files with 12 additions and 14 deletions
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20
sys/kern/vfs_subr.c
View File

@ -5365,13 +5365,6 @@ extattr_check_cred(struct vnode *vp, int attrnamespace, struct ucred *cred,
}
#ifdef DEBUG_VFS_LOCKS
/*
* This only exists to suppress warnings from unlocked specfs accesses. It is
* no longer ok to have an unlocked VFS.
*/
#define IGNORE_LOCK(vp) (KERNEL_PANICKED() || (vp) == NULL || \
(vp)->v_type == VCHR || (vp)->v_type == VBAD)
int vfs_badlock_ddb = 1; /* Drop into debugger on violation. */
SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0,
"Drop into debugger on lock violation");
@ -5431,26 +5424,31 @@ assert_vop_locked(struct vnode *vp, const char *str)
{
int locked;
if (!IGNORE_LOCK(vp)) {
if (KERNEL_PANICKED() || vp == NULL)
return;
locked = VOP_ISLOCKED(vp);
if (locked == 0 || locked == LK_EXCLOTHER)
vfs_badlock("is not locked but should be", str, vp);
}
}
void
assert_vop_unlocked(struct vnode *vp, const char *str)
{
if (KERNEL_PANICKED() || vp == NULL)
return;
if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
vfs_badlock("is locked but should not be", str, vp);
}
void
assert_vop_elocked(struct vnode *vp, const char *str)
{
if (KERNEL_PANICKED() || vp == NULL)
return;
if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
vfs_badlock("is not exclusive locked but should be", str, vp);
}
#endif /* DEBUG_VFS_LOCKS */