On Thu, Aug 25, 2016 at 04:39:13PM -0700, Darrick J. Wong wrote: > From: Christoph Hellwig <hch@xxxxxx> > > Have xfs_vm_bmap return zero for reflinked files. This hack prevents > using a file with shared blocks as a swap file, because we don't want > to deal with CoW when we're (probably) low on memory. > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > [darrick.wong@xxxxxxxxxx: add a more descriptive changelog] Which happens to be incorrect :) The swap code uses ->bmap to build a logical to physical block map at swapon time (to avoid allocations or even just block mappings under memory pressure I suspect). This means we'd get reliable data corruption when COWing a swap file. > + * The swap code (ab-)uses ->bmap to get a block mapping and then > + * bypasse?? the file system for actual I/O. We really can't allow Also it seems like I introduced some weird character instead of an "s" here.. -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
