Bug 202799

Summary: ext3 fails to mount a 16T filesystem due to overflows
Product: [Fedora] Fedora Reporter: Eric Sandeen <esandeen>
Component: kernelAssignee: Eric Sandeen <esandeen>
Status: CLOSED RAWHIDE QA Contact: Brian Brock <bbrock>
Severity: medium Docs Contact:
Priority: medium    
Version: 6CC: jarod, mgarski, wtogami
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OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2006-10-04 16:35:22 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 202807    
Bug Blocks: 206721    

Description Eric Sandeen 2006-08-16 15:07:10 UTC 
Although patches recently went into the kernel to change block containers to
unsigned types, arithmetic on those types can still cause overflows.

This is immediately obvious at mount time, when attempting to mount a filesystem
with 2^32-1 blocks.*

Care must be taken when iterating over group descriptors, and calculating group
descriptor count, to not overflow towards the end of the filesystem.

These patches are now upstream in the -mm kernel, for ext2 and ext3.

*actually creating such a filesystem requires changes to e2fsprogs, addressed by
another bugzilla entry, still to come.
Comment 1 Jarod Wilson 2006-08-18 14:50:47 UTC 
And for the record, said patches are working on two test boxes I've got.

# df -h /mnt/sparsefs/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/sparsefs   16T   25G   15T   1% /mnt/sparsefs
Comment 2 Eric Sandeen 2006-10-04 16:35:22 UTC 
in fc6 stream now.