Author: trasz
Date: Thu May 18 20:29:47 2017
New Revision: 318485
URL: https://svnweb.freebsd.org/changeset/base/318485
Log:
MFC r316941:
Don't try to write out bufs that have already failed with ENXIO.
This fixes some panics after disconnecting mounted disks.
Modified:
stable/11/sys/kern/vfs_bio.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/kern/vfs_bio.c
==============================================================================
--- stable/11/sys/kern/vfs_bio.c Thu May 18 20:15:35 2017
(r318484)
+++ stable/11/sys/kern/vfs_bio.c Thu May 18 20:29:47 2017
(r318485)
@@ -2303,18 +2303,28 @@ brelse(struct buf *bp)
bdirty(bp);
}
if (bp->b_iocmd == BIO_WRITE && (bp->b_ioflags & BIO_ERROR) &&
+ (bp->b_error != ENXIO || !LIST_EMPTY(&bp->b_dep)) &&
!(bp->b_flags & B_INVAL)) {
/*
- * Failed write, redirty. Must clear BIO_ERROR to prevent
- * pages from being scrapped.
+ * Failed write, redirty. All errors except ENXIO (which
+ * means the device is gone) are expected to be potentially
+ * transient - underlying media might work if tried again
+ * after EIO, and memory might be available after an ENOMEM.
+ *
+ * Do this also for buffers that failed with ENXIO, but have
+ * non-empty dependencies - the soft updates code might need
+ * to access the buffer to untangle them.
+ *
+ * Must clear BIO_ERROR to prevent pages from being scrapped.
*/
bp->b_ioflags &= ~BIO_ERROR;
bdirty(bp);
} else if ((bp->b_flags & (B_NOCACHE | B_INVAL)) ||
(bp->b_ioflags & BIO_ERROR) || (bp->b_bufsize <= 0)) {
/*
- * Either a failed read I/O or we were asked to free or not
- * cache the buffer.
+ * Either a failed read I/O, or we were asked to free or not
+ * cache the buffer, or we failed to write to a device that's
+ * no longer present.
*/
bp->b_flags |= B_INVAL;
if (!LIST_EMPTY(&bp->b_dep))
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