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would sometimes result in a corrupted file was reported via email. This problem appears to have been caused by r251719 (reverting r251719 fixed the problem). Although I have not been able to reproduce this problem, I suspect it is caused by another thread increasing np->n_size after the mtx_unlock(&np->n_mtx) but before the vnode_pager_setsize() call. Since the np->n_mtx mutex serializes updates to np->n_size, doing the vnode_pager_setsize() with the mutex locked appears to avoid the problem. Unfortunately, vnode_pager_setsize() where the new size is smaller, cannot be called with a mutex held. This patch returns the semantics to be close to pre-r251719 (actually pre-r248567, r248581, r248567 for the new client) such that the call to vnode_pager_setsize() is only delayed until after the mutex is unlocked when np->n_size is shrinking. Since the file is growing when being written, I believe this will fix the corruption. A better solution might be to replace the mutex with a sleep lock, but that is a non-trivial conversion, so this fix is hoped to be sufficient in the meantime. Reported by: David G. Lawrence (dg@dglawrence.com) Tested by: David G. Lawrence (to be done soon) Reviewed by: kib MFC after: 1 week
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