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, 10 insertions, 2 deletions

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 77b09750e92c..3f9949fee391 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -652,7 +652,10 @@ xfs_buf_item_unlock(
 
 	/*
 	 * If the buf item isn't tracking any data, free it, otherwise drop the
-	 * reference we hold to it.
+	 * reference we hold to it. If we are aborting the transaction, this may
+	 * be the only reference to the buf item, so we free it anyway
+	 * regardless of whether it is dirty or not. A dirty abort implies a
+	 * shutdown, anyway.
 	 */
 	clean = 1;
 	for (i = 0; i < bip->bli_format_count; i++) {
@@ -664,7 +667,12 @@ xfs_buf_item_unlock(
 	}
 	if (clean)
 		xfs_buf_item_relse(bp);
-	else
+	else if (aborted) {
+		if (atomic_dec_and_test(&bip->bli_refcount)) {
+			ASSERT(XFS_FORCED_SHUTDOWN(lip->li_mountp));
+			xfs_buf_item_relse(bp);
+		}
+	} else
 		atomic_dec(&bip->bli_refcount);
 
 	if (!hold)