On Sat, Apr 12, 2014 at 09:59:06AM -0400, Theodore Ts'o wrote: > On Fri, Apr 11, 2014 at 08:57:44PM +0200, Lukas Czerner wrote: > > Currently in do_fallocate in collapse range case we're checking whether > > offset + len is not bigger than i_size. However there is nothing which > > would prevent i_size from changing so the check is pointless. It should > > be done in the file system itself and the file system needs to make sure > > that i_size is not going to change. > > > > As it is now we can easily crash kernel by having two processes doing > > truncate and fallocate collapse range at the same time. This can be > > reproduced on ext4 and it is theoretically possible on xfs even though I > > was not able to trigger it with this simple test. > > > > This commit removes the check from do_fallocate and adds it to the file > > system. > > > > Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx> > > --- > > fs/ext4/extents.c | 11 +++++++++-- > > fs/open.c | 8 -------- > > fs/xfs/xfs_file.c | 10 +++++++++- > > 3 files changed, 18 insertions(+), 11 deletions(-) > > Looks good to me. Do the xfs folks mind if I carry this in the ext4 > tree and push it to Linus shortly after -rc1? If so, please send me > an ack'ed by. No, go ahead. I was going to do the same thing, anyway, if nobody else beat me to it... Acked-by: Dave Chinner <david@xxxxxxxxxxxxx> Cheers, Dave -- Dave Chinner david@xxxxxxxxxxxxx -- 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
