On Tue, Apr 14, 2015 at 05:26:50PM +1000, Dave Chinner wrote: > From: Dave Chinner <dchinner@xxxxxxxxxx> > > When we are doing AIO DIO writes, the IOLOCK only provides an IO > submission barrier. When we need to do EOF zeroing, we need to ensure > that no other IO is in progress and all pending in-core EOF updates > have been completed. This requires us to wait for all outstanding > AIO DIO writes to the inode to complete and, if necessary, run their > EOF updates. > > Once all the EOF updates are complete, we can then restart > xfs_file_aio_write_checks() while holding the IOLOCK_EXCL, knowing > that EOF is up to date and we have exclusive IO access to the file > so we can run EOF block zeroing if we need to without interference. > This gives EOF zeroing the same exclusivity against other IO as we > provide truncate operations. > > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> > --- Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx> > fs/xfs/xfs_file.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 5d5b4ba..c398ec7 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -587,6 +587,16 @@ restart: > xfs_rw_iunlock(ip, *iolock); > *iolock = XFS_IOLOCK_EXCL; > xfs_rw_ilock(ip, *iolock); > + > + /* > + * We now have an IO submission barrier in place, but > + * AIO can do EOF updates during IO completion and hence > + * we now need to wait for all of them to drain. Non-AIO > + * DIO will have drained before we are given the > + * XFS_IOLOCK_EXCL, and so for most cases this wait is a > + * no-op. > + */ > + inode_dio_wait(inode); > goto restart; > } > error = xfs_zero_eof(ip, *pos, i_size_read(inode), &zero); > -- > 2.0.0 > > _______________________________________________ > xfs mailing list > xfs@xxxxxxxxxxx > http://oss.sgi.com/mailman/listinfo/xfs _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
