Don't do null Setattr RPCs for VA_MARK_ATIME. When we added the
VA_MARK_ATIME feature to fix POSIX conformance fore execve() and mmap(), we thought that it was optimized well enough for the one file system that supports it (ffs) and harmless for other file systems (except layered ones which already get the layering for VOP_SETATTR() wrong). However, nfs_setattr() doesn't do much parameter checking, so when it gets a combination of parameters that it doesn't understand, it always does a Setattr RPC. This RPC can't do anything good, and for VA_MARK_ATIME it is null except for wasting a lot of time. This is the smallest and easiest to fix of several bugs that have increased the number of RPCs for kernel builds on nfs by more than 100% since 2004-11-05. The real-time increase depends on network latency and parallelization and can also be very large (approaching the same percentage for unparallelized operations like "make depend" on systems with fast CPUs and high-latency networks).
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svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=163341
@ -668,9 +668,9 @@ nfs_setattr(struct vop_setattr_args *ap)
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#endif
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/*
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* Setting of flags is not supported.
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* Setting of flags and marking of atimes are not supported.
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*/
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if (vap->va_flags != VNOVAL)
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if (vap->va_flags != VNOVAL || (vap->va_vaflags & VA_MARK_ATIME))
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return (EOPNOTSUPP);
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/*
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