Differential D33128

vfs: fully lockless v_writecount adjustment
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Authored by mjg on Nov 26 2021, 1:03 PM.

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rGe511bd1406fa: vfs: fully lockless v_writecount adjustment

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rG FreeBSD src repository

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mjg created this revision.Nov 26 2021, 1:03 PM

Herald added a subscriber: imp. · View Herald TranscriptNov 26 2021, 1:03 PM

upload correct patch

kib added inline comments.Nov 27 2021, 12:33 AM

sys/kern/vfs_default.c
1322	Isn't this unsafe? You should ref the vnode before adding 1 to execcount if you ever saw n == 0, and rollback before returning if actually used cmpset was for n < 0.

mjg added inline comments.Nov 27 2021, 1:21 PM

sys/kern/vfs_default.c
1322	this can only be a problem if someone bogusly adjusts writecount back to 0, but i can make the change if you insist

mjg updated this revision to Diff 99075.Nov 27 2021, 2:43 PM

mjg retitled this revision from vfs: fully lockless v_writecount adjustmen to vfs: fully lockless v_writecount adjustment.

kib accepted this revision.Nov 27 2021, 9:22 PM

This revision is now accepted and ready to land.Nov 27 2021, 9:22 PM

Closed by commit rGe511bd1406fa: vfs: fully lockless v_writecount adjustment (authored by mjg). · Explain WhyNov 27 2021, 11:19 PM

This revision was automatically updated to reflect the committed changes.

mjg added a commit: rGe511bd1406fa: vfs: fully lockless v_writecount adjustment.

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sys/

kern/

126 lines

Diff 99075

sys/kern/vfs_default.c

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