[SVN-4858] FSFS corruption - Found malformed header - Corrupt node-revision

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Cannot Reproduce
• Assignee: Unassigned
• Reporter: Julian Foad
• Created: 01/Jun/20 10:56
• Updated: 02/Mar/21 15:39
• Resolved: 10/Jun/20 15:02

Description

This issue exists to document a form of repository corruption that has been seen "in the wild".

The following error was seen by a WANdisco customer at the time of calling the FS layer commit-txn API via WANdisco's own replicator product:

160004 Found malformed header '2-8080.0-58760.r87127/41271' in revision file
160004 Corrupt node-revision '2-8080.0-58760.r87127/41275'

I can artificially create a repository corruption that produces that exact form of error, in a 1.6-compatible repository served by svn 1.10, in standard Subversion. By my analysis the error almost certainly resulted from this kind of corruption.

The essence of the corruption is: within a directory representation, in either a 'dir' entry or a 'file' entry, add 4 to the byte-offset part of the entry's node-rev reference.

The observed failure was in a FSFS repo format 5, filesystem format 4, shard size 1000, 60 shards packed; the error reported references r87127 so is in a non-packed revision.

 

Issue Links

• blocks: SVN-3885 FSFS corruption issues