On Tue, Jul 21, 2015 at 10:11:05AM -0500, Eric Sandeen wrote: > > > > On Jul 21, 2015, at 7:31 AM, Brian Foster <bfoster@xxxxxxxxxx> wrote: > > > >> On Thu, Jul 16, 2015 at 01:20:30PM -0500, Eric Sandeen wrote: > >> My prior commit, aaf90a2 xfs_copy: fix copy of hard 4k devices > >> causes xfs_copy to emit a CRC error warning when copying a > >> CRC filesystem. > >> > >> This is because we are now reading the maximum sector size, > >> and attempting to verify the CRC based on that (likely incorrect) > >> length. > >> > >> In xfs_db, we currently just don't verify this read, so it's > >> not a problem. In xfs_copy, we almost certainly want to verify. > >> > >> So, first do the maximal read with no verifier; once it's read, > >> drop that buffer, and re-read with the proper sector size and > >> verifier. > >> > >> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> > >> --- > >> > >> diff --git a/copy/xfs_copy.c b/copy/xfs_copy.c > >> index 44a32e8..fd96e15 100644 > >> --- a/copy/xfs_copy.c > >> +++ b/copy/xfs_copy.c > >> @@ -654,11 +654,17 @@ main(int argc, char **argv) > >> > >> memset(&mbuf, 0, sizeof(xfs_mount_t)); > >> libxfs_buftarg_init(&mbuf, xargs.ddev, xargs.logdev, xargs.rtdev); > >> + /* We don't yet know the sector size, so read maximal size */ > >> sbp = libxfs_readbuf(mbuf.m_ddev_targp, XFS_SB_DADDR, > >> - 1 << (XFS_MAX_SECTORSIZE_LOG - BBSHIFT), > >> - 0, &xfs_sb_buf_ops); > >> + 1 << (XFS_MAX_SECTORSIZE_LOG - BBSHIFT), 0, NULL); > >> sb = &mbuf.m_sb; > >> libxfs_sb_from_disk(sb, XFS_BUF_TO_SBP(sbp)); > >> + /* Do it again, now with proper length and verifier */ > >> + libxfs_putbuf(sbp); > >> + libxfs_purgebuf(sbp); > > > > Why the purge? On a quick look, it looks like the buffer cache code > > would handle this if the buffer size changes. > > > > Hmm, is it to ensure the verification occurs if the buffer size doesn't > > actually change? If so, I'd suggest to enhance the comment. :) > > > Without the purge, a re-read of a different size at the same offset seems to cause cache mismatch problems. > Ok, fair enough. Care to update the comment? Otherwise this seems good to me: Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx> > Eric > > > Brian > > > >> + sbp = libxfs_readbuf(mbuf.m_ddev_targp, XFS_SB_DADDR, > >> + 1 << (sb->sb_sectlog - BBSHIFT), > >> + 0, &xfs_sb_buf_ops); > >> > >> /* > >> * For now, V5 superblock filesystems are not supported without -d; > >> > >> _______________________________________________ > >> xfs mailing list > >> xfs@xxxxxxxxxxx > >> http://oss.sgi.com/mailman/listinfo/xfs > > _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
