Re: [RFD] FS behavior (I/O failure) in kernel summit

[Jeff Mahoney <jeffm@suse.com>]

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Dave Chinner wrote:
>>Well it seems to me that all the XFS code does is check to see if the FS
>>is in a shutdown state really early in the call path.
> 
> FYI, the up front checks in XFS are simply to stop new I/O from starting
> if we're already in the shutdown state.
> 
> However, there's more than that in XFS - there's checks all through
> it's I/O paths so that I/Os and transactions in flight at (or
> started after) the time of the shutdown can be aborted before doing
> further damage to a potentially corrupted filesystem. This part
> cannot be done generically as it is intimately tied to the
> filesystem.
> 
> It is also worth noting that XFS won't shutdown a filesystem on just
> any I/O error. Shutdowns due to I/O errors only occur when the
> failure has the potential to leave the filesystem in an inconsistent
> state.  Hence any given operation can return different errors
> depending on where the I/O error occurred in XFS and what effect
> that I/O error has on the consistency of the filesystem.....

Sorry, I should have clarified. I was only refering to the handling of
operations that aren't already in flight.

Currently, ReiserFS (and ext3) will set the filesystem read-only on
error, which ends up returning -EROFS in situations where that error
code is correct, but not entirely appropriate.

- -Jeff

- --
Jeff Mahoney
SuSE Labs
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