Bug 147969
| Summary: | msync(..., ..., MS_SYNC) returning before data written to disk | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 3 | Reporter: | Chris Richards <chris.richards> |
| Component: | kernel | Assignee: | Larry Woodman <lwoodman> |
| Status: | CLOSED ERRATA | QA Contact: | Brian Brock <bbrock> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 3.0 | CC: | agk, bstevens, jturner, pcormier, peterm, petrides, riel, sct, tao, tburke, tkincaid |
| Target Milestone: | --- | Keywords: | Regression |
| Target Release: | --- | ||
| Hardware: | i686 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2005-04-22 20:17:34 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: | |||
| Bug Depends On: | |||
| Bug Blocks: | 132991 | ||
linux-2.4.21-mmap-updates.patch lines 193/4 seem to be the problem. Upper limit test on end >= vma->vm_end fails when you sync the whole memory mapped area, but returns error (==0 ==success) so that you have no idea that it hasn't sync'ed anything at all. The patch to fix this problem was sent to rhkernel-list and has recieved the nexessary ACKs for inclusion in RHEL3-U5. Larry Woodman A fix for this problem has just been committed to the RHEL3 U5 patch pool this evening (in kernel version 2.4.21-27.16.EL). A fix for this problem has also been committed to the RHEL3 E5 patch pool this afternoon (in kernel version 2.4.21-27.0.4.EL). An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2005-293.html An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2005-294.html |
From Bugzilla Helper: User-Agent: Mozilla/5.0 (compatible; Konqueror/3.2) (KHTML, like Gecko) Description of problem: Calling msync(p, size, MS_SYNC) on a memory mapped file is not waiting for the data to be flushed to disk [eg a 128Mb chunk of data is claiming to be flushed in 1-2ms : cf 2.4.21-15 / 2.6.8-1.521 where the same test code takes 2-3s to do this] This means that there is no way for code to know that the data it has just written to a memory mapped file has actually made it to disk. Version-Release number of selected component (if applicable): kernel-2.4.21-20.EL and kernel-2.4.21-27.0.2.EL How reproducible: Always Steps to Reproduce: 1.mmap a (large-ish) file 2.write some data into the memory region 3.call msync with the MS_SYNC option 4.reboot the PC by hitting the power switch once msync has completed... [or time how long it takes to sync the data] 5.look at the contents of the file Actual Results: Data missing from file on disk (was present in file (ie disk buffers) prior to hitting power) Expected Results: msync should wait for the data to be written to disk when the MS_SYNC flag is used. Additional info: