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| author | kib <kib@FreeBSD.org> | 2013-07-09 20:49:32 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2013-07-09 20:49:32 +0000 |
| commit | a7b76b76e17881d47ffd2715135b3512e07d0fbf (patch) | |
| tree | 163763327fb3a8dbae9807ce2cbea1c3bb9f69f6 /contrib/libc++/src/debug.cpp | |
| parent | 247743cbbaf231a82a50f74ca849e50b747d1401 (diff) | |
| download | FreeBSD-src-a7b76b76e17881d47ffd2715135b3512e07d0fbf.zip FreeBSD-src-a7b76b76e17881d47ffd2715135b3512e07d0fbf.tar.gz | |
There are several code sequences like
vfs_busy(mp);
vfs_write_suspend(mp);
which are problematic if other thread starts unmount between two
calls. The unmount starts a write, while vfs_write_suspend() drain
writers. On the other hand, unmount drains busy references, causing
the deadlock.
Add a flag argument to vfs_write_suspend and require the callers of it
to specify VS_SKIP_UNMOUNT flag, when the call is performed not in the
mount path, i.e. the covered vnode is not locked. The suspension is
not attempted if VS_SKIP_UNMOUNT is specified and unmount is in
progress.
Reported and tested by: Andreas Longwitz <longwitz@incore.de>
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
Diffstat (limited to 'contrib/libc++/src/debug.cpp')
0 files changed, 0 insertions, 0 deletions
