[SCM] Hurd branch, master, updated. v0.9.git20230520-30-g6f5bf154

[Samuel Thibault]

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- Log -----------------------------------------------------------------
commit 6f5bf154ba60bc5067760fcaf52a222ee7e2bc2e
Author: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date:   Sat Aug 12 21:22:12 2023 +0200

    file-syncfs: Avoid deadlock
    
    This is a four-player problem (here for diskfs):
    
    - One runs sync, which calls diskfs_S_file_syncfs, which triggers
      fsys_syncfs on all active translators, while keeping the
      translator_ihash_lock lock.
    
    - One of the active translators is hung, for some reason
    
    - Another ext2fs thread is trying to call fshelp_set_active_translator from
      dir_lookup. It is stuck on trying to acquire translator_ihash_lock, and it
      holds the np.
    
    - The ext2fs thread running diskfs_sync_everything tries to lock that
      np, while holding the nodecache_lock.
    
    In the end everything is locked. While diskfs_S_file_syncfs can as well just
    atomically get the list of active translators, and then call fsys_syncfs
    without keeping translator_ihash_lock held.

-----------------------------------------------------------------------

Summary of changes:
 libdiskfs/file-syncfs.c | 36 +++++++++++++++++++-----------------
 libnetfs/file-syncfs.c  | 35 +++++++++++++++++++----------------
 2 files changed, 38 insertions(+), 33 deletions(-)


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