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Re: CVS commit: src/sys/fs/tmpfs
On Jan 3, 2014, at 10:18 PM, J. Hannken-Illjes
> On Jan 3, 2014, at 10:13 PM, Mindaugas Rasiukevicius
> <rmind%netbsd.org@localhost> wrote:
>> "Juergen Hannken-Illjes" <hannken%netbsd.org@localhost> wrote:
>>> Module Name: src
>>> Committed By: hannken
>>> Date: Fri Jan 3 09:53:12 UTC 2014
>>> Modified Files:
>>> src/sys/fs/tmpfs: tmpfs_subr.c tmpfs_vnops.c
>>> Log Message:
>>> Fix a race where thread1 runs VOP_REMOVE() and gets preempted in
>>> tmpfs_reclaim() before the call to tmpfs_free_node(). Thread2
>>> runs VFS_FHTOVP() and gets a new vnode attached to the node thread1
>>> is about to destroy.
>>> Change tmpfs_alloc_node() to always assign non-zero generation number
>>> and tmpfs_inactive() to set the generation number of unlinked nodes
>>> to zero.
>> Can you explain how does this help? It still seems racy to me.
> Please describe the race in more detail. Tmpfs_fhtovp() will fail
> as soon as an unlinked tmpfs node drops its last vnode reference.
Ok -- got it. We check the generation number too early in tmpfs_fhtovp().
Should be fixed with tmpfs_vfsops.c Rev. 1.55
J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig
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