[Precise][SRU][PATCH 1/1] Revert "xfs: fix _xfs_buf_find oops on blocks beyond the filesystem end"

[Luis Henriques]

BugLink: http://bugs.launchpad.net/bugs/1236041

This reverts commit 150c8fee1a79a70043605185f88e38a2cb6bb64f which is
commit eb178619f930fa2ba2348de332a1ff1c66a31424 upstream.

Several people have reported issues using xfs_growfs after applying the
CVE-2013-1819 fix backport:

[  133.574503] XFS (loop0): _xfs_buf_find: Block out of range: block 0x500001, EOFS 0x400000
[  133.575554] XFS (loop0): _xfs_buf_find: Block out of range: block 0x500001, EOFS 0x400000

Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/xfs/xfs_buf.c | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index c13fff4..2f5a8f7 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -434,7 +434,6 @@ _xfs_buf_find(
 	struct rb_node		**rbp;
 	struct rb_node		*parent;
 	xfs_buf_t		*bp;
-	xfs_daddr_t		eofs;
 
 	range_base = (ioff << BBSHIFT);
 	range_length = (isize << BBSHIFT);
@@ -443,23 +442,6 @@ _xfs_buf_find(
 	ASSERT(!(range_length < (1 << btp->bt_sshift)));
 	ASSERT(!(range_base & (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 (ioff >= 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__, ioff, eofs);
-		return NULL;
-	}
-
 	/* get tree root */
 	pag = xfs_perag_get(btp->bt_mount,
 				xfs_daddr_to_agno(btp->bt_mount, ioff));
-- 
1.8.3.2