Il 01/02/2013 14:08, Greg Kroah-Hartman ha scritto: > 3.7-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Dave Chinner <dchin...@redhat.com> > > commit eb178619f930fa2ba2348de332a1ff1c66a31424 upstream. > > When _xfs_buf_find is passed an out of range address, it will fail > to find a relevant struct xfs_perag and oops with a null > dereference. This can happen when trying to walk a filesystem with a > metadata inode that has a partially corrupted extent map (i.e. the > block number returned is corrupt, but is otherwise intact) and we > try to read from the corrupted block address. > > In this case, just fail the lookup. If it is readahead being issued, > it will simply not be done, but if it is real read that fails we > will get an error being reported. Ideally this case should result > in an EFSCORRUPTED error being reported, but we cannot return an > error through xfs_buf_read() or xfs_buf_get() so this lookup failure > may result in ENOMEM or EIO errors being reported instead.
It looks like this breaks xfs_growfs. See http://bugzilla.redhat.com/show_bug.cgi?id=909602. Paolo > Signed-off-by: Dave Chinner <dchin...@redhat.com> > Reviewed-by: Brian Foster <bfos...@redhat.com> > Reviewed-by: Ben Myers <b...@sgi.com> > Signed-off-by: Ben Myers <b...@sgi.com> > Cc: CAI Qian <caiq...@redhat.com> > Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> > > --- > fs/xfs/xfs_buf.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > --- a/fs/xfs/xfs_buf.c > +++ b/fs/xfs/xfs_buf.c > @@ -487,6 +487,7 @@ _xfs_buf_find( > struct rb_node *parent; > xfs_buf_t *bp; > xfs_daddr_t blkno = map[0].bm_bn; > + xfs_daddr_t eofs; > int numblks = 0; > int i; > > @@ -498,6 +499,23 @@ _xfs_buf_find( > ASSERT(!(numbytes < (1 << btp->bt_sshift))); > ASSERT(!(BBTOB(blkno) & (xfs_off_t)btp->bt_smask)); > > + /* > + * Corrupted block numbers can get through to here, unfortunately, so we > + * have to check that the buffer falls within the filesystem bounds. > + */ > + eofs = XFS_FSB_TO_BB(btp->bt_mount, btp->bt_mount->m_sb.sb_dblocks); > + if (blkno >= eofs) { > + /* > + * XXX (dgc): we should really be returning EFSCORRUPTED here, > + * but none of the higher level infrastructure supports > + * returning a specific error on buffer lookup failures. > + */ > + xfs_alert(btp->bt_mount, > + "%s: Block out of range: block 0x%llx, EOFS 0x%llx ", > + __func__, blkno, eofs); > + return NULL; > + } > + > /* get tree root */ > pag = xfs_perag_get(btp->bt_mount, > xfs_daddr_to_agno(btp->bt_mount, blkno)); > > -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
