John Baldwin 5aefb4cbbf Close a race in NFS lookup processing that could result in stale name cache ... entries on one client when a directory was renamed on another client. The root cause for the stale entry being trusted is that each per-vnode nfsnode structure has a single 'n_ctime' timestamp used to validate positive name cache entries. However, if there are multiple entries for a single vnode, they all share a single timestamp. To fix this, extend the name cache to allow filesystems to optionally store a timestamp value in each name cache entry. The NFS clients now fetch the timestamp associated with each name cache entry and use that to validate cache hits instead of the timestamps previously stored in the nfsnode. Another part of the fix is that the NFS clients now use timestamps from the post-op attributes of RPCs when adding name cache entries rather than pulling the timestamps out of the file's attribute cache. The latter is subject to races with other lookups updating the attribute cache concurrently. Some more details: - Add a variant of nfsm_postop_attr() to the old NFS client that can return a vattr structure with a copy of the post-op attributes. - Handle lookups of "." as a special case in the NFS clients since the name cache does not store name cache entries for ".", so we cannot get a useful timestamp. It didn't really make much sense to recheck the attributes on the the directory to validate the namecache hit for "." anyway. - ABI compat shims for the name cache routines are present in this commit so that it is safe to MFC. MFC after: 2 weeks		2012-01-20 20:02:01 +00:00
..
nfs_bio.c	Rename vm_page_set_valid() to vm_page_set_valid_range().	2011-11-30 17:39:00 +00:00
nfs_kdtrace.c
nfs_krpc.c	jwd@ reported a problem via email where the old NFS client would	2011-12-21 02:45:51 +00:00
nfs_nfsiod.c
nfs_node.c	Fix a LOR in the NFS client which could cause a deadlock.	2011-08-02 11:24:42 +00:00
nfs_subs.c	Close a race in NFS lookup processing that could result in stale name cache	2012-01-20 20:02:01 +00:00
nfs_vfsops.c	Make sure all intermediate variables holding mount flags (mnt_flag)	2012-01-17 01:08:01 +00:00
nfs_vnops.c	Close a race in NFS lookup processing that could result in stale name cache	2012-01-20 20:02:01 +00:00
nfs.h	Fix a comment that got missed by r221973 which changed	2011-05-16 13:12:09 +00:00
nfsargs.h
nfsm_subs.h	Close a race in NFS lookup processing that could result in stale name cache	2012-01-20 20:02:01 +00:00
nfsmount.h
nfsnode.h	Close a race in NFS lookup processing that could result in stale name cache	2012-01-20 20:02:01 +00:00
nfsstats.h
nlminfo.h