OpenAFS Master Repository branch, master, updated. openafs-devel-1_5_76-3661-g42351db

[Gerrit Code Review]

The following commit has been merged in the master branch:
commit 42351db75e04e46012208d38f80dc17be7ab776d
Author: Mark Vitale <mvitale@sinenomine.net>
Date:   Tue Mar 12 22:13:20 2013 -0400

    dafs: prevent corruption in large fsstate.dat files
    
    If while writing to the fsstate.dat file, it exceeds the current
    size of the file (multiples of FS_STATE_INIT_FILESIZE (8MiB)),
    we call fs_stateResizeFile.  This un-mmaps, truncates, and
    re-mmaps the file.  Unfortunately, fs_stateMapFile() resets the
    state->mmap.offset and .cursor, so any writes in flight over
    the resize will overwrite the first bytes of the file (and leave
    zeros in the file where the data should have been written).
    
    Upon return from the write that caused a file resize, the offset
    is eventually corrected and the state dump continues with a
    silent failure.  Eventually the state dump completes and the
    file header is rewritten; this may conceal some or all of
    the overwrite damage at offset 0.  However, any zeros near the 8MiB
    offset (and its multiples) remain as corruption.
    
    Add a flag to fs_stateMapFile() to allow the caller to specify if
    the offset and cursor should be preserved.  Modify fs_stateResizeFile()
    to use this capability.
    
    testing note: temporarily reduced FS_STATE_INIT_FILESIZE to 256 bytes
    during testing in order to make the problem easier to reproduce.
    This problem would normally occur only on relatively large/active
    DAFS fileservers.
    
    Change-Id: I9b6c57ef7727837ae7cfc00d02192983355dad2b
    Reviewed-on: http://gerrit.openafs.org/9599
    Tested-by: BuildBot <buildbot@rampaginggeek.com>
    Reviewed-by: Derrick Brashear <shadow@your-file-system.com>

 src/viced/serialize_state.c |   20 ++++++++++++++------
 1 files changed, 14 insertions(+), 6 deletions(-)

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