Use buf to send speedup
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Authored by imp on Jan 9 2020, 11:10 PM.

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mckusick
chs

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rS356819: Use buf to send speedup

Summary

It turns out there's a problem with using g_io to send the speedup. It leads to
a race when there's a resource shortage when a disk fails.

Instead, send BIO_SPEEDUP via struct buf. This is pretty straight forward,
except we need to transfer the bio_flags from b_ioflags for BIO_SPEEDUP commands
in g_vfs_strategy.

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Repository

rS FreeBSD src repository - subversion

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Event Timeline

imp created this revision.Jan 9 2020, 11:10 PM

Harbormaster completed remote builds in B28584: Diff 66582.Jan 9 2020, 11:10 PM

imp added reviewers: mckusick, chs.Jan 9 2020, 11:11 PM

I have never been a fan of short-circuiting the layers, so am fine with keeping them intact.

This revision is now accepted and ready to land.Jan 13 2020, 4:47 AM

minor nit: the returned "resid" value is unused. otherwise looks good.

In D23117#508978, @chs wrote:

minor nit: the returned "resid" value is unused. otherwise looks good.

I go back and forth on this. I'd like the interface to return how much of the shortage it could handle, but neither place I use it now does....
I'll take it out for now.

Closed by commit rS356819: Use buf to send speedup (authored by imp). · Explain WhyJan 17 2020, 1:16 AM

This revision was automatically updated to reflect the committed changes.

imp added a commit: rS356819: Use buf to send speedup.