Access Violation when the network connection is lost and VSI_CACHE=true

[AndresPozo]

Expected behavior and actual behavior.

The GeoTIFF driver produces an Access Violation when reading from a network drive and the connection is lost. This only happens when VSI_CACHE=TRUE. When VSI_CACHE=FALSE, the reading fails, but there is no Access Violation.

My hypothesis is that in cpl_vsi_cache.cpp there are many calls to "poBase->Seek" and "poBase->Read" that do not check if there is an error in the underlying calls.

Steps to reproduce the problem.

1 - Open a big enough GeoTIFF in a network share.
2 - Disconnect the network.
3 - Do several reads from random parts of the file.
4 - Access Violation

Operating system

Windows 10 Pro x64

GDAL version and provenance

GDAL 3.2.0 from https://www.gisinternals.com/

[AndresPozo]

Many thanks Rouault!!
I still have a doubt: In the VSICachedFile::LoadBlocks method, line 304 there is an unchecked poBase->Seek. Wouldn't it be necessary to check it as it is done in the call to poBase->Seek on line 343? I don't know the code well, so I don't know if the check is necessary.

[rouault]

I still have a doubt: In the VSICachedFile::LoadBlocks method, line 304 there is an unchecked poBase->Seek.

I've just added a check for consistency, but I believe I've never seen a Seek() failing (seeking beyond the extent of a file is a valid operation for example)