OpenAFS Master Repository branch, master, updated. BP--openafs-stable-1_6_x-1337-g31a001f

[Gerrit Code Review]

The following commit has been merged in the master branch:
commit 31a001f60e5fe729b315f679d1d43b367bd74ea5
Author: Andrew Deason <adeason@sinenomine.net>
Date:   Wed Jun 29 13:51:22 2011 -0500

    SOLARIS: Granular multiPage detection
    
    Currently, a struct vcache has a multiPage counter, indicating how
    many afs_getpage requests are in-flight for that vcache that involve
    retrieving multiple pages. Any dcache associated with such vcaches are
    then avoided when choosing dcache entries to evict from the cache,
    since we may deadlock when trying to evict a dcache entry from one of
    the earlier afs_GetOnePage calls in a particular afs_getpage request.
    
    This behavior can cause the client to become unusable if the cache
    becomes full, and the only items in the cache are dcache entries in a
    file that has an in-flight multi-page afs_getpage request. Since, in
    that case, we cannot kick out any entries from the cache, and so we
    wait forever to wait for the cache utilization to go down.
    
    To prevent this from occurring, record exactly which ranges in the
    file have in-flight multi-page afs_getpage requests, and just avoid
    dcache entries in those ranges. This way afs_GetDownD can evict dcache
    entries in the same file, but still avoid entries that would cause a
    deadlock.
    
    Also add some comments explaining this situation a bit more.
    
    Change-Id: Idb305c8b7511065301739542772d16d4fe8cd574
    Reviewed-on: http://gerrit.openafs.org/4896
    Reviewed-by: Derrick Brashear <shadow@dementia.org>
    Tested-by: BuildBot <buildbot@rampaginggeek.com>

 src/afs/SOLARIS/osi_vcache.c   |    2 ++
 src/afs/SOLARIS/osi_vm.c       |   28 ++++++++++++++++++++++++++++
 src/afs/SOLARIS/osi_vnodeops.c |   29 +++++++++++++++++++++++++++--
 src/afs/afs.h                  |   17 ++++++++++++++++-
 src/afs/afs_dcache.c           |   12 ++++++++----
 src/afs/afs_prototypes.h       |    1 +
 6 files changed, 82 insertions(+), 7 deletions(-)

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