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Chris LuandGitHub
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* mount: leave the target alone when a move has no source MovePath cleared whatever sat at the target before it checked that the source was still there, so a move it then declined to make had already taken the target's mapping apart. The same rename reaching the table twice - once for an open handle, once for the invalidation behind it - was enough to leave the moved inode with no path at all. * mount: move the inode table when a rename arrives from the cluster A rename made by another client reaches this mount only as a metadata event, and the only table update on that path sat inside the open-file-handle branch. Every other inode the kernel still addresses by nodeid kept resolving to its pre-rename path, so the next operation on it went to a path the filer no longer has. Move the entry for every rename invalidation. The filer sends one event per moved entry, so a renamed directory's children follow their parent without a descendant walk. * mount: move the inode table exactly once per rename event Making MovePath return early on a missing source was the wrong half to fix. The source is also missing when the rename came from a client that never visited it, and there the destination really was replaced and has to be unlinked - the early return kept the name resolving to a file the rename destroyed, so a dirty handle on it could still flush over what took its place. The two cases are indistinguishable from inside MovePath, so leave it alone and stop calling it twice: invalidateOpenFileHandle reports whether it moved, and the handler moves only when it did not. Both paths mark a replaced file's handle deleted, which the no-handle path previously did not do at all. * mount: leave a rename alone unless the source is still ours to move Two ways the fallback move could act on state it did not own. A handle whose version guard skipped the event never reached RememberPath, so moving the table under it left the handle flushing to the pre-rename path; the handle path owns its inode's rename, so the fallback now runs only for an inode without one. And the subscription can redeliver a rename once it falls out of the 4096-entry dedup ring. A replay found no source and a live target, unlinked the mapping the first delivery had just made, and marked the moved file's handle deleted - worse than the stale path this set out to fix. Only a source still in the table is moved now. That gives up unlinking a destination the rename replaced when the source was never visited here, which is where this started. It is what the mount already did before this branch, and it is the safer of the two: retaining a stale name costs a wrong lookup, while unlinking the wrong one costs a file's dirty data. * mount: decide a rename move inside the table's lock The source-presence check sat outside MovePath, so two invalidations for one rename could both see the source and the loser would unlink what the winner had just placed - the same damage the check was added to prevent. MovePath makes the decision under its own lock now and reports that nothing moved. The handle a rename destroyed is also marked from the caller rather than from inside invalidateOpenFileHandle, which was setting isDeleted bare on a second handle while holding the first one's lock. markHandleDeleted already takes the lock the flush reads that flag under, and marking from the caller keeps it to one handle lock at a time. The invalidation test harness wires onEntryInvalidation now, the way the mount does, rather than reaching past it. * mount: apply a rename ahead of the handle's version fence The fence exists so an old event cannot roll a handle's entry back to stale content. A rename carries no content: it says the name the inode answered to is gone. Skipping one on the strength of the fence left the inode and the handle both pointing at a name the filer had vacated, and no fallback ran either, since a handle owns its inode's rename. Applied before the fence now, and only when MovePath reports the source was still ours to move - which is what keeps a replayed rename from remembering a path the handle has already moved past.