Bug 221973
| Summary: | cam iosched: BIO_ZONE commands probably shouldn't use the read queue | ||||||
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| Product: | Base System | Reporter: | Fabian Keil <fk> | ||||
| Component: | kern | Assignee: | Warner Losh <imp> | ||||
| Status: | Closed FIXED | ||||||
| Severity: | Affects Some People | CC: | emaste, imp | ||||
| Priority: | --- | Keywords: | patch | ||||
| Version: | CURRENT | Flags: | fk:
mfc-stable11?
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| Hardware: | Any | ||||||
| OS: | Any | ||||||
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A commit references this bug: Author: imp Date: Wed Sep 20 21:13:21 UTC 2017 New revision: 323828 URL: https://svnweb.freebsd.org/changeset/base/323828 Log: cam iosched: Use the write queue for BIO_ZONE commands Use the write queue for BIO_ZONE commands so they can't get executed ahead of writes that were sent after them. More generally, since they introduce strong ordering into the list, they need to go to the write queue (which is the only queue that BIO_ORDERED is honored for at the moment). In fact, fix mismatch between queueing and dequeueing code by changing this to queue all non-reads (and non-trims) to the write queue. As a side effect this prevents the kernel message: kernel: Found bio_cmd = 0x9 which cam_iosched_next_bio() emits when finding commands other than BIO_READ in the read queue. PR: 221973 Obtained from: ElectroBSD Submitted by: Fabian Keil Differential Revision: https://reviews.freebsd.org/D12353 Changes: head/sys/cam/cam_iosched.c MFC plans? ^Triage: Assign to committer resolving With bugmeister hat, I think any possible MFCs from 3 years ago are OBE. |
Created attachment 185970 [details] cam iosched: Use the write queue for BIO_ZONE commands The attached patch lets iosched put BIO_ZONE commands on the write queue so they can't get executed ahead of writes that were sent after them. I'm not completely sure but believe that this is less likely to cause problems than putting them one the read queue. As I currently don't use SMR drives the patch hasn't been properly tested. It prevents the kernel message: kernel: Found bio_cmd = 0x9 which cam_iosched_next_bio() emits when finding commands other than BIO_READ in the read queue, though. The fact that BIO_ZONE commands are sometimes sent to non-SMR drives may indicate another problem but I haven't looked into this yet. Obtained from: ElectroBSD