Differential D19737

Handle ro remount of tmpfs rw mount.
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Authored by kib on Mar 28 2019, 3:55 PM.

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Commits

rS345803: tmpfs: plug holes on rw->ro mount update.
rS345800: tmpfs: ignore tmpfs_set_status() if mount point is read-only.
rS345799: Block creation of the new nodes for read-only tmpfs mounts.

Summary

In particular:

suspend the mount around vflush() to avoid new writes come after the vnode is processed
flush pending metadata updates (mostly node times)
remap all rw mappings of files from the mount into ro (this is not clear to me how to handle best, might be revoke the mapping at all)
disable metadata updates after the mp is ro

Diff Detail

Repository

rS FreeBSD src repository - subversion

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Event Timeline

kib created this revision.Mar 28 2019, 3:55 PM

Herald added a subscriber: imp. · View Herald TranscriptMar 28 2019, 3:55 PM

Harbormaster completed remote builds in B23349: Diff 55539.Mar 28 2019, 3:55 PM

At the moment this is FYI, the patch is the work in progress. Most important, it handles things I know are broken already, but complete audit of tmpfs is needed to identify the rest of it.

Looks good to my VFS-naive eye. Thanks!

This revision is now accepted and ready to land.Mar 28 2019, 5:36 PM

kib added a subscriber: pho.Mar 30 2019, 2:14 PM

Update diff to the fixed committable version.

This revision now requires review to proceed.Apr 2 2019, 1:37 PM

Harbormaster completed remote builds in B23469: Diff 55728.Apr 2 2019, 1:37 PM

This revision was not accepted when it landed; it landed in state Needs Review.Apr 2 2019, 1:41 PM

Closed by commit rS345799: Block creation of the new nodes for read-only tmpfs mounts. (authored by kib). · Explain Why

This revision was automatically updated to reflect the committed changes.