John Baldwin 12ac99dc46 Close a race with caching of -ve name lookups in the NFS client. ... Specifically, clients only trust -ve cache entries while the directory remains unchanged and discard any -ve cache entries for a directory when they notice that the modification time of a directory entry changes. The race involves two concurrent lookups as follows: - Thread A does a lookup for file 'foo' which sends a lookup RPC to the server. The lookup fails and the server replies. - The 'foo' file is created (either by the same client or a different client) updating the modification time on the parent directory of 'foo'. - Thread B does a lookup for a different file 'bar' which updates the cached attributes of the parent directory of 'foo' to reflect the new modification time after 'foo' was created. - Thread A finally resumes execution to parse the reply from the NFS server. It adds a -ve cache entry and sets the cached value of the directory's modification time that is used for invalidating -ve cached lookups to the new modification time set by thread B. At this point, future lookups of 'foo' will honor the -ve cached entry until the cached entry is pushed out of the name cache's LRU or the modification time of the parent directory is changed again by some other change. The fix is to read the directory's modification time before sending the lookup RPC and use that cached modification time when setting the directory's cached modification time. Also, we do not add a -ve cache entry if another thread has added -ve cache entry that set the directory's cached modification time to a newer value than the value we read before sending the lookup RPC. Reviewed by: rmacklem MFC after: 1 week		2009-10-16 19:30:48 +00:00
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bootp_subr.c	Rework global locks for interface list and index management, correcting	2009-08-23 20:40:19 +00:00
krpc_subr.c	Remove the old kernel RPC implementation and the NFS_LEGACYRPC option.	2009-06-30 19:03:27 +00:00
krpc.h
nfs_bio.c	Use PBDRY flag for msleep(9) in NFS and NLM when sleeping thread owns	2009-07-14 22:54:29 +00:00
nfs_diskless.c	Merge the remainder of kern_vimage.c and vimage.h into vnet.c and	2009-08-01 19:26:27 +00:00
nfs_kdtrace.c	Add a MODULE_DEPEND() on the NFS client from dtnfsclient so that dtnfsclient	2009-10-12 18:58:42 +00:00
nfs_kdtrace.h	Fix two bugs in DTrace tracing of accesscache and attrcache load events:	2009-03-24 23:16:48 +00:00
nfs_krpc.c	Adjust the internal NFS KPI to avoid the last traces of NFS_LEGACYRPC.	2009-06-30 19:10:17 +00:00
nfs_lock.c	Remove the old kernel RPC implementation and the NFS_LEGACYRPC option.	2009-06-30 19:03:27 +00:00
nfs_lock.h
nfs_nfsiod.c	Remove the old kernel RPC implementation and the NFS_LEGACYRPC option.	2009-06-30 19:03:27 +00:00
nfs_node.c	Add LK_NOWITNESS to the vn_lock() calls done on newly created nfs	2009-09-09 20:37:49 +00:00
nfs_subs.c	In nfs_upgrade_vnlock(), assert that the vnode is locked. It is for all	2009-08-14 10:59:17 +00:00
nfs_vfsops.c	Reverting the previous change for now. Some users reports the patch	2009-09-15 22:09:42 +00:00
nfs_vnops.c	Close a race with caching of -ve name lookups in the NFS client.	2009-10-16 19:30:48 +00:00
nfs.h	Adjust the internal NFS KPI to avoid the last traces of NFS_LEGACYRPC.	2009-06-30 19:10:17 +00:00
nfsargs.h
nfsdiskless.h
nfsm_subs.h	Remove the old kernel RPC implementation and the NFS_LEGACYRPC option.	2009-06-30 19:03:27 +00:00
nfsmount.h	Use PBDRY flag for msleep(9) in NFS and NLM when sleeping thread owns	2009-07-14 22:54:29 +00:00
nfsnode.h	Remove the unmaintained University of Michigan NFSv4 client from 8.x	2009-05-22 12:35:12 +00:00
nfsstats.h
nlminfo.h