>Number:         10463
>Category:       kern
>Synopsis:       LFS: kernel code can mistakenly clear SEGSUM_ACTIVE bit it segment summary struct
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jun 27 11:07:01 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator:     Jim Evans
>Release:        1.4.2
>Organization:
Cray
>Environment:
N/A 

>Description:

lfs_segment.c:545-546.  Code fails to convert lfs_nextseg from daddr 
to segment number prior to using it to index into ifile structures.  
Typically causes checkpoint flushes to mistakenly clear the active 
segment's SEGSUM_ACTIVE bit.  

Typically leads to some of the symptoms described in pr kern/8889
>How-To-Repeat:
Aggravated by small/busy LFS filesystems & small cleanerd sleep intervals. 
>Fix:
510,511c510,511
<                       if (fs->lfs_curseg/fs->lfs_sepb==(ibno-fs->lfs_cleansz))
<                               ((SEGUSE *)(bp->b_data))[fs->lfs_curseg%fs->lfs_sepb].su_flags |= SEGUSE_ACTIVE;
---
>                       if (datosn(fs, fs->lfs_curseg)/fs->lfs_sepb==(ibno-fs->lfs_cleansz))
>                               ((SEGUSE *)(bp->b_data))[datosn(fs, fs->lfs_curseg)%fs->lfs_
>Release-Note:
>Audit-Trail:
>Unformatted: