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由 Jeff Layton 提交于
We currently can hit a deadlock (of sorts) when trying to use flexfiles layouts with XFS. XFS will call break_layout when something wants to write to the file. In the case of the (super-simple) flexfiles layout driver in knfsd, the MDS and DS are the same machine. The client can get a layout and then issue a v3 write to do its I/O. XFS will then call xfs_break_layouts, which will cause a CB_LAYOUTRECALL to be issued to the client. The client however can't return the layout until the v3 WRITE completes, but XFS won't allow the write to proceed until the layout is returned. Christoph says: XFS only cares about block-like layouts where the client has direct access to the file blocks. I'd need to look how to propagate the flag into break_layout, but in principle we don't need to do any recalls on truncate ever for file and flexfile layouts. If we're never going to recall the layout, then we don't even need to set the lease at all. Just skip doing so on flexfiles layouts by adding a new flag to struct nfsd4_layout_ops and skipping the lease setting and removal when that flag is true. Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: NJeff Layton <jlayton@redhat.com> Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
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