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https://issues.apache.org/jira/browse/MYNEWT-160?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Christopher Collins closed MYNEWT-160.
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Resolution: Fixed
> NFFS - Files with scattered data blocks can cause restore failures
> ------------------------------------------------------------------
>
> Key: MYNEWT-160
> URL: https://issues.apache.org/jira/browse/MYNEWT-160
> Project: Mynewt
> Issue Type: Bug
> Components: NFFS
> Reporter: Christopher Collins
> Assignee: Christopher Collins
> Fix For: v0_8_0_beta2
>
>
> If a file's data blocks are written to disk in an "unexpected" order, the
> subsequent restore operation can fail in a few ways:
> 1. The restore fails with an FS_ECORRUPT error code.
> 2. The file is only partially restored; the end of the file will be
> inaccessible.
> This bug is rooted in the inconvenient data structure that NFFS uses for
> chained data blocks (reverse singly-linked list). The data structure is
> inconvenient, but it is used to minimize RAM and flash usage.
> On disk, each data block indicates the ID of the preceding data block in the
> parent file. In RAM, a file inode provides access to all the constituent
> data blocks by maintaining a pointer to the last data block.
> The bug is that the NFFS code does not always ensure that a file inode points
> to its last data block. The code assumes that data blocks will be restored
> in order of increasing file offset. If data blocks are restored in any other
> order, this bug occurs.
> The correct fix will be quite involved. I am going to implement a quick fix
> for 0.8.0 which fixes the bug, but introduces some horrible inefficiencies
> when large files are restored. I will schedule a proper fix for 0.9.0.
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