On 08/17/2011 02:29 AM, Ted Ts'o wrote: > On Tue, Aug 16, 2011 at 02:37:53PM +0800, Tao Ma wrote: >> From: Tao Ma <boyu.mt@xxxxxxxxxx> >> >> EXT4_IO_END_UNWRITTEN flag set and the increase of i_aiodio_unwritten should >> be done simultaneously since ext4_end_io_nolock always clear the flag and >> decrease the counter in the same time. >> >> We don't increase i_aiodio_unwritten when setting EXT4_IO_END_UNWRITTEN so >> it will go nagative and causes some process to wait forever. >> >> Part of the patch came from Eric in his e-mail, but it doesn't fix the problem >> met by Michael actually. >> http://marc.info/?l=linux-ext4&m=131316851417460&w=2 >> >> Reported-and-Tested-by: Michael Tokarev<mjt@xxxxxxxxxx> >> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> >> Signed-off-by: Tao Ma <boyu.mt@xxxxxxxxxx> > > Thanks I've taken this into the ext4 tree. I am a bit worried this > will trigger a GCC warning: > > + /* > + * It may be over-defensive here to check EXT4_IO_END_UNWRITTEN now, > + * but being more careful is always safe for the future change. > + */ > inode = io_end->inode; > + if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) { > + io_end->flag |= EXT4_IO_END_UNWRITTEN; > + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + } > > /* Add the io_end to per-inode completed io list*/ > spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); > > ... since in Google we've been compiling with -Werror, but it's not > causing an error on gcc 4.4, which is what I still have on my laptop. > It may be that newer versions of GCC are smart enough to notice tha > the above is dead code, and then complain with a warning. Sorry for my bluntness. But where is the 'dead code' you mean? Thanks Tao -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
