Merge tag 'for-linus-v3.8-rc6' of git://oss.sgi.com/xfs/xfs

Pull xfs bugfixes from Ben Myers:
 "Here are fixes for returning EFSCORRUPTED on probe of a non-xfs
  filesystem, the stack switch in xfs_bmapi_allocate, a crash in
  _xfs_buf_find, speculative preallocation as the filesystem nears
  ENOSPC, an unmount hang, a race with AIO, and a regression with
  xfs_fsr:

   - fix return value when filesystem probe finds no XFS magic, a
     regression introduced in 9802182.

   - fix stack switch in __xfs_bmapi_allocate by moving the check for
     stack switch up into xfs_bmapi_write.

   - fix oops in _xfs_buf_find by validating that the requested block is
     within the filesystem bounds.

   - limit speculative preallocation near ENOSPC.

   - fix an unmount hang in xfs_wait_buftarg by freeing the
     xfs_buf_log_item in xfs_buf_item_unlock.

   - fix a possible use after free with AIO.

   - fix xfs_swap_extents after removal of xfs_flushinval_pages, a
     regression introduced in commit fb59581404a."

* tag 'for-linus-v3.8-rc6' of git://oss.sgi.com/xfs/xfs:
  xfs: Fix xfs_swap_extents() after removal of xfs_flushinval_pages()
  xfs: Fix possible use-after-free with AIO
  xfs: fix shutdown hang on invalid inode during create
  xfs: limit speculative prealloc near ENOSPC thresholds
  xfs: fix _xfs_buf_find oops on blocks beyond the filesystem end
  xfs: pull up stack_switch check into xfs_bmapi_write
  xfs: Do not return EFSCORRUPTED when filesystem probe finds no XFS magic

1 files changed, 20 insertions, 0 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 56d1614760c..fbbb9eb92e3 100644
--- 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));
@@ -1487,6 +1505,8 @@ restart:
 	while (!list_empty(&btp->bt_lru)) {
 		bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru);
 		if (atomic_read(&bp->b_hold) > 1) {
+			trace_xfs_buf_wait_buftarg(bp, _RET_IP_);
+			list_move_tail(&bp->b_lru, &btp->bt_lru);
 			spin_unlock(&btp->bt_lru_lock);
 			delay(100);
 			goto restart;