OpenAFS Master Repository branch, master, updated. openafs-devel-1_9_1-266-gd460b61

[Gerrit Code Review]

The following commit has been merged in the master branch:
commit d460b616ebad763f7e480e194b2bffc28df99721
Author: Andrew Deason <adeason@sinenomine.net>
Date:   Fri Apr 7 16:09:30 2023 -0500

    LINUX: Make 'fs flush*' invalidate dentry
    
    Our 'fs flush' and related commands (flushall, flushvolume) clear the
    relevant entries in the OpenAFS stat cache and data cache, which can
    fix problems if the cache ever becomes incorrect for any reason. (This
    can happen after bugs, repairing corrupted volumes, disaster recovery
    scenarios, and similar edge cases.)
    
    However, on Linux, these commands don't affect the VFS dentry cache.
    If someone needs to use an 'fs flush' command to fix a problem, this
    will fix the OpenAFS cache, but the Linux dcache can still be wrong.
    The only way to manually flush dcache entries is to use the global
    'drop_caches' mechanism, which is a very heavweight operation, only
    accessible to root.
    
    For example:
    
        $ ls -l
        ls: cannot access foo.1: No such file or directory
        total 2
        drwxrwxr-x. 2 bin adeason 2048 Apr  6 14:20 dir
        -?????????? ? ?   ?          ?            ? foo.1
        $ fs flush .
        $ ls -l
        ls: cannot access foo.1: No such file or directory
        total 2
        drwxrwxr-x. 2 bin adeason 2048 Apr  6 14:20 dir
        -?????????? ? ?   ?          ?            ? foo.1
        $ sudo sysctl -q -w vm.drop_caches=3
        $ ls -l
        total 3
        drwxrwxr-x. 2 bin adeason 2048 Apr  6 14:20 dir
        -rw-rw-r--. 1 bin adeason   29 Sep 22  2022 foo.1
    
    To make the 'fs flush' commands be effective in more situations,
    change afs_ResetVCache() to also invalidate the dcache entries
    associated with each vcache we reset. To make things simpler and
    reduce locking complexity, do this by setting d_time to 0, and don't
    directly run dcache-managing functions like d_invalidate or d_drop,
    etc.
    
    The above example now becomes:
    
        $ ls -l
        ls: cannot access foo.1: No such file or directory
        total 2
        drwxrwxr-x. 2 bin adeason 2048 Apr  6 14:20 dir
        -?????????? ? ?   ?          ?            ? foo.1
        $ fs flush .
        $ ls -l
        total 3
        drwxrwxr-x. 2 bin adeason 2048 Apr  6 14:20 dir
        -rw-rw-r--. 1 bin adeason   29 Sep 22  2022 foo.1
    
    Change-Id: Ic95ef6137f5b671baf68a4890ef1562f029af794
    Reviewed-on: https://gerrit.openafs.org/15391
    Reviewed-by: Cheyenne Wills <cwills@sinenomine.net>
    Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
    Tested-by: BuildBot <buildbot@rampaginggeek.com>

 src/afs/LINUX/osi_compat.h    |  4 ++++
 src/afs/LINUX/osi_vcache.c    | 53 +++++++++++++++++++++++++++++++++++++++++++
 src/afs/afs_osi.h             |  6 +++++
 src/afs/afs_vcache.c          |  2 ++
 src/cf/linux-kernel-struct.m4 |  3 +++
 5 files changed, 68 insertions(+)

-- 
OpenAFS Master Repository