On 2/7/12 4:07 PM, Eric Sandeen wrote: > journal_unmap_buffer()'s zap_buffer: code clears a lot of buffer head > state ala discard_buffer(), but does not touch _Delay or _Unwritten > as discard_buffer() does. > > This can be problematic in some areas of the ext4 code which assume > that if they have found a buffer marked unwritten or delay, then it's > a live one. Perhaps those spots should check whether it is mapped > as well, but if jbd2 is going to tear down a buffer, let's really > tear it down completely. > > Without this I get some fsx failures on sub-page-block filesystems > up until v3.2, at which point 4e96b2dbbf1d7e81f22047a50f862555a6cb87cb > and 189e868fa8fdca702eb9db9d8afc46b5cb9144c9 make the failures go > away, because buried within that large change is some more flag > clearing. I still think it's worth doing in jbd2, since > ->invalidatepage leads here directly, and it's the right place > to clear away these flags. Addresses CVE-2011-4086 BTW. > Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > --- > > diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c > index 35ae096..52653306 100644 > --- a/fs/jbd2/transaction.c > +++ b/fs/jbd2/transaction.c > @@ -1949,6 +1949,8 @@ zap_buffer_unlocked: > clear_buffer_mapped(bh); > clear_buffer_req(bh); > clear_buffer_new(bh); > + clear_buffer_delay(bh); > + clear_buffer_unwritten(bh); > bh->b_bdev = NULL; > return may_free; > } > > > -- > 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 -- 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
