Patch Name:  PHKL_9153

Patch Description: s700 10.20 NFS server hang; write gathering support

Creation Date: 96/11/26

Post Date:  96/11/27

Hardware Platforms - OS Releases:
        s700: 10.20

Products: N/A

Filesets:
        JournalFS.VXFS-BASE-KRN OS-Core.CORE-KRN

Automatic Reboot?: Yes

Status: General Superseded

Critical:
        No (superseded patches were critical)
        PHKL_8294: HANG

Path Name:  /hp-ux_patches/s700/10.X/PHKL_9153

Symptoms:
        PHKL_9153:
        Add write-gathering support for NFS servers.

        PHKL_8294:
        When multiple nfsd's access the same file simultaneously,
        they hang in a deadlock.

Defect Description:
        PHKL_9153:
        Added code to update the v_last_fsync field on the vnode.
        This field will be used by rfs_write to implement write
        gathering on nfs servers. Patch PHKL_9155/56, which updates
        rfs_write(), must also be applied for this patch to be
        effective. If both patches are applied, server throughput
        should increase for write-intensive workloads, and I/O
        traffic to disk should decrease.

        PHKL_8294:
        ufs_bread(), called by nfs server routines, prematurely
        unlocks the inode while the caller still owns the buffer.
        This opens a window for another process to grab the inode
        lock. Deadlock occurs when the process owning the buffer
        tries to access the inode again and the process holding
        the inode waits for the buffer to be available before
        it can release the inode lock.

        The fix is to delay the inode unlocking in ufs_bread()
        until the inode is no longer needed.

SR:
        4701341669 5003330910

Patch Files:
        /usr/conf/lib/libhp-ux.a(vfs.o)
        /usr/conf/lib/libufs.a(ufs_vnops.o)
        /usr/conf/lib/libvxfs_base.a(vx_vnops.o)

what(1) Output:
        /usr/conf/lib/libhp-ux.a(vfs.o):
                vfs.c          $Date: 96/11/22 17:33:45 $ $Revision:
                         1.25.98.11 $ PATCH_10.20 (PHKL_9153)
        /usr/conf/lib/libufs.a(ufs_vnops.o):
                ufs_vnops.c    $Date: 96/11/22 17:34:38 $ $Revision:
                         1.30.98.17 $ PATCH_10.20 (PHKL_9153)
        /usr/conf/lib/libvxfs_base.a(vx_vnops.o):
                vx_vnops.c     $Date: 96/11/22 17:35:07 $ $Revision:
                         1.8.98.21 $ PATCH_10.20 (PHKL_9153)

cksum(1) Output:
        1148147061 20444 /usr/conf/lib/libhp-ux.a(vfs.o)
        3381483645 33300 /usr/conf/lib/libufs.a(ufs_vnops.o)
        690801697 26052 /usr/conf/lib/libvxfs_base.a(vx_vnops.o)

Patch Conflicts: None

Patch Dependencies:  None

Hardware Dependencies:  None

Other Dependencies:  None

Supersedes:
        PHKL_8294

Equivalent Patches:
        PHKL_9154:
        s800: 10.20

Patch Package Size:  140 Kbytes

Installation Instructions:
        Please review all instructions and the Hewlett-Packard
        SupportLine User Guide or your Hewlett-Packard support terms
        and conditions for precautions, scope of license,
        restrictions, and, limitation of liability and warranties,
        before installing this patch.
        ------------------------------------------------------------
        1. Back up your system before installing a patch.

        2. Login as root.

        3. Copy the patch to the /tmp directory.

        4. Move to the /tmp directory and unshar the patch:

                cd /tmp
                sh PHKL_9153

        5a. For a standalone system, run swinstall to install the
            patch:

                swinstall -x autoreboot=true -x match_target=true \
                        -s /tmp/PHKL_9153.depot

        5b. For a homogeneous NFS Diskless cluster run swcluster on the
            server to install the patch on the server and the clients:

                swcluster -i -b

            This will invoke swcluster in the interactive mode and
            force all clients to be shut down.

            WARNING: All cluster clients must be shut down prior to the
                     patch installation.  Installing the patch while the
                     clients are booted is unsupported and can lead to
                     serious problems.

            The swcluster command will invoke an swinstall session in which
            you must specify:

                alternate root path  -  default is /export/shared_root/OS_700
                source depot path    -  /tmp/PHKL_9153.depot

            To complete the installation, select the patch by choosing
            "Actions -> Match What Target Has" and then "Actions -> Install"
            from the Menubar.

        5c. For a heterogeneous NFS Diskless cluster:

                - run swinstall on the server as in step 5a to install
                  the patch on the cluster server.

                - run swcluster on the server as in step 5b to install
                  the patch on the cluster clients.

        By default swinstall will archive the original software in
        /var/adm/sw/patch/PHKL_9153.  If you do not wish to retain a
        copy of the original software, you can create an empty file
        named /var/adm/sw/patch/PATCH_NOSAVE.

        Warning: If this file exists when a patch is installed, the
                 patch cannot be deinstalled.  Please be careful
                 when using this feature.

        It is recommended that you move the PHKL_9153.text file to
        /var/adm/sw/patch for future reference.

        To put this patch on a magnetic tape and install from the
        tape drive, use the command:

                dd if=/tmp/PHKL_9153.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions:  None