xfs: remove the leftover xfs_{set,clear}_li_failed infrastructure

Marking a log item as failed kept a buffer reference around for
resubmission of inode and dquote items.

For inode items commit 298f7be ("xfs: pin inode backing buffer to
the inode log item") started pinning the inode item buffers
unconditionally and removed the need for this.  Later commit acc8f86
("xfs: attach dquot buffer to dquot log item buffer") did the same for
dquot items but didn't fully clean up the xfs_clear_li_failed side
for them.  Stop adding the extra pin for dquot items and remove the
helpers.

This happens to fix a call to xfs_buf_free with the AIL lock held,
which would be incorrect for the unlikely case freeing the buffer
ends up calling vfree.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

Author: Christoph Hellwig

fs/xfs/xfs_dquot.c

@@ -1186,9 +1186,8 @@ xfs_qm_dqflush_done(
 	if (test_bit(XFS_LI_IN_AIL, &lip->li_flags) &&
 	    (lip->li_lsn == qlip->qli_flush_lsn ||
 	     test_bit(XFS_LI_FAILED, &lip->li_flags))) {
-
 		spin_lock(&ailp->ail_lock);
-		xfs_clear_li_failed(lip);
+		clear_bit(XFS_LI_FAILED, &lip->li_flags);
 		if (lip->li_lsn == qlip->qli_flush_lsn) {
 			/* xfs_ail_update_finish() drops the AIL lock */
 			tail_lsn = xfs_ail_delete_one(ailp, lip);

fs/xfs/xfs_inode_item.c

@@ -1089,13 +1089,7 @@ xfs_iflush_abort(
 	 * state. Whilst the inode is in the AIL, it should have a valid buffer
 	 * pointer for push operations to access - it is only safe to remove the
 	 * inode from the buffer once it has been removed from the AIL.
-	 *
-	 * We also clear the failed bit before removing the item from the AIL
-	 * as xfs_trans_ail_delete()->xfs_clear_li_failed() will release buffer
-	 * references the inode item owns and needs to hold until we've fully
-	 * aborted the inode log item and detached it from the buffer.
 	 */
-	clear_bit(XFS_LI_FAILED, &iip->ili_item.li_flags);
 	xfs_trans_ail_delete(&iip->ili_item, 0);
 
 	/*

fs/xfs/xfs_trans_ail.c

@@ -909,10 +909,9 @@ xfs_trans_ail_delete(
 		return;
 	}
 
-	/* xfs_ail_update_finish() drops the AIL lock */
-	xfs_clear_li_failed(lip);
+	clear_bit(XFS_LI_FAILED, &lip->li_flags);
 	tail_lsn = xfs_ail_delete_one(ailp, lip);
-	xfs_ail_update_finish(ailp, tail_lsn);
+	xfs_ail_update_finish(ailp, tail_lsn);	/* drops the AIL lock */
 }
 
 int

fs/xfs/xfs_trans_priv.h

@@ -167,32 +167,4 @@ xfs_trans_ail_copy_lsn(
 }
 #endif
 
-static inline void
-xfs_clear_li_failed(
-	struct xfs_log_item	*lip)
-{
-	struct xfs_buf	*bp = lip->li_buf;
-
-	ASSERT(test_bit(XFS_LI_IN_AIL, &lip->li_flags));
-	lockdep_assert_held(&lip->li_ailp->ail_lock);
-
-	if (test_and_clear_bit(XFS_LI_FAILED, &lip->li_flags)) {
-		lip->li_buf = NULL;
-		xfs_buf_rele(bp);
-	}
-}
-
-static inline void
-xfs_set_li_failed(
-	struct xfs_log_item	*lip,
-	struct xfs_buf		*bp)
-{
-	lockdep_assert_held(&lip->li_ailp->ail_lock);
-
-	if (!test_and_set_bit(XFS_LI_FAILED, &lip->li_flags)) {
-		xfs_buf_hold(bp);
-		lip->li_buf = bp;
-	}
-}
-
 #endif	/* __XFS_TRANS_PRIV_H__ */