[PATCH 1/2] xfs: introduce XFS_BMAPI_STACK_SWITCH

[Mark Tinguely]

On 10/04/12 20:06, Dave Chinner wrote:
> From: Dave Chinner<dchinner at redhat.com>
>
> Certain allocation paths through xfs_bmapi_write() are in situations
> where we have limited stack available. These are almost always in
> the buffered IO writeback path when convertion delayed allocation
> extents to real extents.
>
> The current stack switch occurs for userdata allocations, which
> means we also do stack switches for preallocation, direct IO and
> unwritten extent conversion, even those these call chains have never
> been implicated in a stack overrun.
>
> Hence, let's target just the single stack overun offended for stack
> switches. To do that, introduce a XFS_BMAPI_STACK_SWITCH flag that
> the caller can pass xfs_bmapi_write() to indicate it should switch
> stacks if it needs to do allocation.
>
> Signed-off-by: Dave Chinner<dchinner at redhat.com>
> ---

Looks good.

Reviewed-by: Mark Tinguely <tinguely at sgi.com>