On Sat 23-12-17 16:57:20, Dan Williams wrote: > Catch cases where truncate encounters pages that are still under active > dma. This warning is a canary for potential data corruption as truncated > blocks could be allocated to a new file while the device is still > perform i/o. > > Here is an example of a collision that this implementation catches: > > WARNING: CPU: 2 PID: 1286 at fs/dax.c:343 dax_disassociate_entry+0x55/0x80 > [..] > Call Trace: > __dax_invalidate_mapping_entry+0x6c/0xf0 > dax_delete_mapping_entry+0xf/0x20 > truncate_exceptional_pvec_entries.part.12+0x1af/0x200 > truncate_inode_pages_range+0x268/0x970 > ? tlb_gather_mmu+0x10/0x20 > ? up_write+0x1c/0x40 > ? unmap_mapping_range+0x73/0x140 > xfs_free_file_space+0x1b6/0x5b0 [xfs] > ? xfs_file_fallocate+0x7f/0x320 [xfs] > ? down_write_nested+0x40/0x70 > ? xfs_ilock+0x21d/0x2f0 [xfs] > xfs_file_fallocate+0x162/0x320 [xfs] > ? rcu_read_lock_sched_held+0x3f/0x70 > ? rcu_sync_lockdep_assert+0x2a/0x50 > ? __sb_start_write+0xd0/0x1b0 > ? vfs_fallocate+0x20c/0x270 > vfs_fallocate+0x154/0x270 > SyS_fallocate+0x43/0x80 > entry_SYSCALL_64_fastpath+0x1f/0x96 > > Cc: Jan Kara <jack@xxxxxxx> > Cc: Jeff Moyer <jmoyer@xxxxxxxxxx> > Cc: Christoph Hellwig <hch@xxxxxx> > Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> > Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> Looks good to me. You can add: Reviewed-by: Jan Kara <jack@xxxxxxx> Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
