libata: retry FS IOs even if it has failed with AC_ERR_INVALID

libata currently doesn't retry if a command fails with AC_ERR_INVALID assuming that retrying won't get it any further even if retried. However, a failure may be classified as invalid through hardware glitch (incorrect reading of the error register or firmware bug) and there isn't whole lot to gain by not retrying as actually invalid commands will be failed immediately. Also, commands serving FS IOs are extremely unlikely to be invalid. Retry FS IOs even if it's marked invalid.

Transient and incorrect invalid failure was seen while debugging firmware related issue on Samsung n130 on bko#14314.

http://bugzilla.kernel.org/show_bug.cgi?id=14314

---
 drivers/ata/libata-eh.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Index: ata/drivers/ata/libata-eh.c
===================================================================
@@ -2028,8 +2028,9 @@ static void ata_eh_link_autopsy(struct a
 			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_OTHER);
 
 		/* determine whether the command is worth retrying */
-		if (!(qc->err_mask & AC_ERR_INVALID) &&
-		    ((qc->flags & ATA_QCFLAG_IO) || qc->err_mask != AC_ERR_DEV))
+		if (qc->flags & ATA_QCFLAG_IO ||
+		    (!(qc->err_mask & AC_ERR_INVALID) &&
+		     qc->err_mask != AC_ERR_DEV))
 			qc->flags |= ATA_QCFLAG_RETRY;
 
 		/* accumulate error info */

applied