Re: [PATCH] bulkstat fixups

[Vlad Apostolov <vapo@xxxxxxx>]

It is looking good Lachlan.

I also verified the patch with XFS QA and Judith reported that
it fixed the xfs_bulkstat() problem - skipping inodes in the last AG.

Regards,
Vlad

Lachlan McIlroy wrote:
> Here's a collection of fixups for bulkstat for all the remaining issues.
>
> - sanity check for NULL user buffer in xfs_ioc_bulkstat[_compat]()
>
> - remove the special case for XFS_IOC_FSBULKSTAT with count == 1.  
> This special
>   case causes bulkstat to fail because the special case uses 
> xfs_bulkstat_single()
>   instead of xfs_bulkstat() and the two functions have different 
> semantics.
>   xfs_bulkstat() will return the next inode after the one supplied 
> while skipping
>   internal inodes (ie quota inodes).  xfs_bulkstate_single() will only 
> lookup the
>   inode supplied and return an error if it is an internal inode.
>
> - in xfs_bulkstat(), need to initialise 'lastino' to the inode 
> supplied so in cases
>   were we return without examining any inodes the scan wont restart 
> back at zero.
> - sanity check for valid *ubcountp values.  Cannot sanity check for 
> valid ubuffer
>   here because some users of xfs_bulkstat() don't supply a buffer.
>
> - checks against 'ubleft' (the space left in the user's buffer) should 
> be against
>   'statstruct_size' which is the supplied minimum object size.  The 
> mixture of
>   checks against statstruct_size and 0 was one of the reasons we were 
> skipping
>   inodes.
>
> - if the formatter function returns BULKSTAT_RV_NOTHING and an error 
> and the error
>   is not ENOENT or EINVAL then we need to abort the scan.  ENOENT is 
> for inodes that
>   are no longer valid and we just skip them.  EINVAL is returned if we 
> try to lookup
>   an internal inode so we skip them too.  For a DMF scan if the inode 
> and DMF
>   attribute cannot fit into the space left in the user's buffer it 
> would return
>   ERANGE.  We didn't handle this error and skipped the inode.  We 
> would continue to
>   skip inodes until one fitted into the user's buffer or we completed 
> the scan.
> - put back the recalculation of agino (that got removed with the last 
> fix) at the
>   end of the while loop.  This is because the code at the start of the 
> loop expects
>   agino to be the last inode examined if it is non-zero.
>
> - if we found some inodes but then encountered an error, return 
> success this time
>   and the error next time.  If the formatter aborted with ENOMEM we 
> will now return
>   this error but only if we couldn't read any inodes.  Previously if 
> we encountered
>   ENOMEM without reading any inodes we returned a zero count and no 
> error which
>   falsely indicated the scan was complete.