Date: Thu, 27 May 2010 18:07:20 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/nfsclient nfs_vnops.c Message-ID: <201005271807.o4RI7hEw088506@repoman.freebsd.org>
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jhb 2010-05-27 18:07:20 UTC
FreeBSD src repository
Modified files:
sys/nfsclient nfs_vnops.c
Log:
SVN rev 208603 on 2010-05-27 18:07:20Z by jhb
More gracefully handle stale file handles and attributes when opening a
file via NFS. Specifically, to satisfy close-to-open-consistency, the NFS
client always performs at least one RPC on a file during an open(2) to see
if the file has changed. Normally this RPC is an ACCESS or GETATTR RPC
that is forced by flushing a file's attribute cache during nfs_open() and
then requesting new attributes. However, if the file is noticed to be
stale during nfs_open(), the only recourse is to fail the open(2) call
with ESTALE. On the other hand, if the ACCESS or GETATTR RPC is sent
during nfs_lookup(), then the NFS client can fall back to a LOOKUP RPC to
obtain the new file handle in the case that a file has been replaced.
This change causes the NFS client to flush the attribute cache during
nfs_lookup() when validating a name cache hit if the attributes fetched
during nfs_lookup() can be reused in nfs_open(). This allows the client
to open a replaced file via the new file handle the first time that it
notices a replaced file rather than failing with ESTALE in some cases.
Reviewed by: rmacklem, bde
Reviewed by: mohans (older version)
MFC after: 1 week
Revision Changes Path
1.326 +20 -3 src/sys/nfsclient/nfs_vnops.c
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