Bug 101555
| Summary: | Kernel doesn't report write errors to applications | ||||||
|---|---|---|---|---|---|---|---|
| Product: | [Retired] Red Hat Linux | Reporter: | yuval yeret <yuval> | ||||
| Component: | kernel | Assignee: | Arjan van de Ven <arjanv> | ||||
| Status: | CLOSED WONTFIX | QA Contact: | Brian Brock <bbrock> | ||||
| Severity: | high | Docs Contact: | |||||
| Priority: | high | ||||||
| Version: | 8.0 | CC: | riel, yuval | ||||
| Target Milestone: | --- | ||||||
| Target Release: | --- | ||||||
| Hardware: | i686 | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2004-09-30 15:41:23 UTC | Type: | --- | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Attachments: |
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Created attachment 93368 [details]
rtest is an easy test to reproduce the problem.
use synced writes
example usage:
rtest -filename=/dev/sdd -count=1000 -sync=1
Thanks for the bug report. However, Red Hat no longer maintains this version of the product. Please upgrade to the latest version and open a new bug if the problem persists. The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases, and if you believe this bug is interesting to them, please report the problem in the bug tracker at: http://bugzilla.fedora.us/ |
Description of problem: Writes to block devices / filesystem mounted over block devices can fail if the block device is suddenly unreachable (e.g. link loss to RAID). Kernel should not acknowledge userspace synced writes in this situation, but surprisingly thats exactly what it does. Version-Release number of selected component (if applicable): 2.4.18-24 Redhat Errata kernel How reproducible: Every time. Steps to Reproduce: 1. from userspace code do synced writes to a block device file (e.g. /dev/sdd) which is actually a RAID LUN / disconnectable SCSI disk. use strace to track the write progress 2. disconnect cable / disk 3. keep tracking write progress Actual results: last write which started before the disconneciton is hung for some time. after a while that write returns ok, and all writes after that return ok as well. after rebooting the machine the data is of course missing Expected results: 1. first write which cannot complete due to disconnection should hang forever. (process should be in D state until a hard kill) this is how SuSE kernel 2.4.20 behaves 2. better - return EIO or other error code to the userspace and let it handle/report the error as it sees fit. Additional info: This was discussed in the linux-kernel mailing list some time ago: [PATCH 2.4] Report write errors to applications - http://lists.insecure.org/lists/linux-kernel/2003/Jan/7178.html (contains suggested patch to marcello's 2.4.21pre3 kernel http://www.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/2.4.21pre5aa1/ 9999_fsync-msync-async-errors-1 - contains patch for the aa kernel