kill-the-bkl/reiserfs: acquire the inode mutex safely

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While searching a pathname, an inode mutex can be acquired
in do_lookup() which calls reiserfs_lookup() which in turn
acquires the write lock.

On the other side reiserfs_fill_super() can acquire the write_lock
and then call reiserfs_lookup_privroot() which can acquire an
inode mutex (the root of the mount point).

So we theoretically risk an AB - BA lock inversion that could lead
to a deadlock.

As for other lock dependencies found since the bkl to mutex
conversion, the fix is to use reiserfs_mutex_lock_safe() which
drops the lock dependency to the write lock.

[ Impact: fix a possible deadlock with reiserfs ]

Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

...

This commit is contained in:

Frederic Weisbecker 2009-05-16 18:12:08 +02:00

parent 2ac626955e

commit c72e05756b

3 changed files with 37 additions and 36 deletions

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34

fs/reiserfs/journal.c

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4

fs/reiserfs/xattr.c

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35

include/linux/reiserfs_fs.h

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