freebsd-skq/sys/nfsclient
Rick Macklem 175b3f31d3 Both NFS clients can deadlock when using the "rdirplus" mount
option. This can occur when an nfsiod thread that already holds
a buffer lock attempts to acquire a vnode lock on an entry in
the directory (a LOR) when another thread holding the vnode lock
is waiting on an nfsiod thread. This patch avoids the deadlock by disabling
readahead for this case, so the nfsiod threads never do readdirplus.
Since readaheads for directories need the directory offset cookie
from the previous read, they cannot normally happen in parallel.
As such, testing by jhb@ and myself didn't find any performance
degredation when this patch is applied. If there is a case where
this results in a significant performance degradation, mounting
without the "rdirplus" option can be done to re-enable readahead
for directories.

Reported and tested by:	jhb
Reviewed by:	jhb
MFC after:	2 weeks
2013-04-18 13:09:04 +00:00
..
nfs_bio.c Both NFS clients can deadlock when using the "rdirplus" mount 2013-04-18 13:09:04 +00:00
nfs_kdtrace.c Fix the module dependency in nfs_kdtrace.c for the old NFS 2011-05-06 19:55:15 +00:00
nfs_krpc.c Further refine the handling of stop signals in the NFS client. The 2013-02-21 19:02:50 +00:00
nfs_nfsiod.c Change the sysctl naming for the old and new NFS clients 2011-05-15 20:52:43 +00:00
nfs_node.c r16312 is not any longer real since many years (likely since when VFS 2012-11-19 22:43:45 +00:00
nfs_subs.c - Use m_get2() instead of nfsm_reqhead(). 2013-03-12 12:23:47 +00:00
nfs_vfsops.c Functions m_getm2() and m_get2() have different order of arguments, 2013-03-12 13:42:47 +00:00
nfs_vnops.c Revert 195703 and 195821 as this special stop handling in NFS is now 2013-03-13 21:06:03 +00:00
nfs.h Fix a comment that got missed by r221973 which changed 2011-05-16 13:12:09 +00:00
nfsargs.h Move the NFSv4.1 client patches over from projects/nfsv4.1-client 2012-12-08 22:52:39 +00:00
nfsm_subs.h - Use m_get2() instead of nfsm_reqhead(). 2013-03-12 12:23:47 +00:00
nfsmount.h Revert 195703 and 195821 as this special stop handling in NFS is now 2013-03-13 21:06:03 +00:00
nfsnode.h PR# 165923 reported intermittent write failures for dirty 2012-05-12 12:02:51 +00:00
nfsstats.h
nlminfo.h