[ ssic-linux-Bugs-1701165 ] 2.6.11-ssi cfs_update_attr() cannot use BKL as i_sem

Bugs item #1701165, was opened at 2007-04-15 18:37
Message generated for change (Settings changed) made by rogertsang
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Category: Filesystem
Group: None
>Status: Closed
Resolution: Fixed
Priority: 5
Private: No
Submitted By: Roger Tsang (rogertsang)
Assigned to: Roger Tsang (rogertsang)
Summary: 2.6.11-ssi cfs_update_attr() cannot use BKL as i_sem

Initial Comment:
As of kernel 2.6.11-ssi the big kernel lock (BKL) implementation has changed.  BKL can no longer be used in place of i_sem in cfs_update_attr().  Either the BKL is used in all Linux + OpenSSI code under i_sem or we fix cfs_update_attr() to use i_sem which is what I'm doing by making the i_sem a responsibility of cfs_update_attr() callers.

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Comment By: Roger Tsang (rogertsang)
Date: 2007-04-19 22:34

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However cfs_refresh_inode() doesn't do locking.  cfs_update_attr() callers
have CFS token and/or already have i_sem.  Testing cfs_update_attr()
without locking.

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Comment By: Roger Tsang (rogertsang)
Date: 2007-04-16 17:47

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Most of the cfs_update_attr() callers have i_sem, but we cannot be sure
that we won't deadlock for code paths that are CFS async because some
writers in base acquire i_sem.  Currently testing cfs_update_attr() that
replaces big kernel lock with a combination of CXLOCK, lock ownership
detection, and blocking and non-blocking i_sem.

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