On 10/13/23 8:13 PM, Jan Kara wrote: > Gao Xiang has reported that on ext4 O_SYNC direct IO does not properly > sync file size update and thus if we crash at unfortunate moment, the > file can have smaller size although O_SYNC IO has reported successful > completion. The problem happens because update of on-disk inode size is > handled in ext4_dio_write_iter() *after* iomap_dio_rw() (and thus > dio_complete() in particular) has returned and generic_file_sync() gets > called by dio_complete(). Fix the problem by handling on-disk inode size > update directly in our ->end_io completion handler. > > References: https://lore.kernel.org/all/02d18236-26ef-09b0-90ad-030c4fe3ee20@xxxxxxxxxxxxxxxxx > Reported-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx> > CC: stable@xxxxxxxxxxxxxxx > Fixes: 378f32bab371 ("ext4: introduce direct I/O write using iomap infrastructure") > Signed-off-by: Jan Kara <jack@xxxxxxx> Tested with the reproducer after applying to 6.6-rc5, Tested-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx> BTW, once backported to older kernel like 5.10, it seems that it depends on the following commit: 936e114a245b iomap: update ki_pos a little later in iomap_dio_complete Otherwise, it will fail the following xfstests cases: generic/091 generic/094 generic/225 generic/263 generic/311 generic/617 Thanks, Joseph
