Date: Wed, 25 Jan 2012 00:22:54 +0000 (UTC) From: Rick Macklem <rmacklem@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r230516 - in head/sys: fs/nfsclient nfsclient Message-ID: <201201250022.q0P0MsEY098760@svn.freebsd.org>
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Author: rmacklem Date: Wed Jan 25 00:22:53 2012 New Revision: 230516 URL: http://svn.freebsd.org/changeset/base/230516 Log: If a mount -u is done to either NFS client that switches it from TCP to UDP and the rsize/wsize/readdirsize is greater than NFS_MAXDGRAMDATA, it is possible for a thread doing an I/O RPC to get stuck repeatedly doing retries. This happens because the RPC will use a resize/wsize/readdirsize that won't work for UDP and, as such, it will keep failing indefinitely. This patch returns an error for this case, to avoid the problem. A discussion on freebsd-fs@ seemed to indicate that returning an error was preferable to silently ignoring the "udp"/"mntudp" option. This problem was discovered while investigating a problem reported by pjd@ via email. MFC after: 2 weeks Modified: head/sys/fs/nfsclient/nfs_clvfsops.c head/sys/nfsclient/nfs_vfsops.c Modified: head/sys/fs/nfsclient/nfs_clvfsops.c ============================================================================== --- head/sys/fs/nfsclient/nfs_clvfsops.c Tue Jan 24 23:43:13 2012 (r230515) +++ head/sys/fs/nfsclient/nfs_clvfsops.c Wed Jan 25 00:22:53 2012 (r230516) @@ -989,6 +989,23 @@ nfs_mount(struct mount *mp) error = EIO; goto out; } + + /* + * Cannot switch to UDP if current rsize/wsize/readdirsize is + * too large, since there may be an I/O RPC in progress that + * will get retried after the switch to the UDP socket. These + * retries will fail over and over and over again. + */ + if (args.sotype == SOCK_DGRAM && + (nmp->nm_rsize > NFS_MAXDGRAMDATA || + nmp->nm_wsize > NFS_MAXDGRAMDATA || + nmp->nm_readdirsize > NFS_MAXDGRAMDATA)) { + vfs_mount_error(mp, + "old rsize/wsize/readdirsize greater than UDP max"); + error = EINVAL; + goto out; + } + /* * When doing an update, we can't change version, * security, switch lockd strategies or change cookie Modified: head/sys/nfsclient/nfs_vfsops.c ============================================================================== --- head/sys/nfsclient/nfs_vfsops.c Tue Jan 24 23:43:13 2012 (r230515) +++ head/sys/nfsclient/nfs_vfsops.c Wed Jan 25 00:22:53 2012 (r230516) @@ -1106,6 +1106,23 @@ nfs_mount(struct mount *mp) error = EIO; goto out; } + + /* + * Cannot switch to UDP if current rsize/wsize/readdirsize is + * too large, since there may be an I/O RPC in progress that + * will get retried after the switch to the UDP socket. These + * retries will fail over and over and over again. + */ + if (args.sotype == SOCK_DGRAM && + (nmp->nm_rsize > NFS_MAXDGRAMDATA || + nmp->nm_wsize > NFS_MAXDGRAMDATA || + nmp->nm_readdirsize > NFS_MAXDGRAMDATA)) { + vfs_mount_error(mp, + "old rsize/wsize/readdirsize greater than UDP max"); + error = EINVAL; + goto out; + } + /* * When doing an update, we can't change from or to * v3, switch lockd strategies or change cookie translation
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