On 10:04 07/09, Dave Chinner wrote: > On Thu, Sep 03, 2020 at 06:32:36PM +0200, Christoph Hellwig wrote: > > We could trivially do something like this to allow the file system > > to call iomap_dio_complete without i_rwsem: > > That just exposes another deadlock vector: > > P0 P1 > inode_lock() fallocate(FALLOC_FL_ZERO_RANGE) > __iomap_dio_rw() inode_lock() > <block> > <submits IO> > <completes IO> > inode_unlock() > <gets inode_lock()> > inode_dio_wait() > iomap_dio_complete() > generic_write_sync() > btrfs_file_fsync() > inode_lock() > <deadlock> Can inode_dio_end() be called before generic_write_sync(), as it is done in fs/direct-io.c:dio_complete()? Christoph's solution is a clean approach and would prefer to use it as the final solution. -- Goldwyn
