Author: kmacy
Date: Sun Aug 30 20:45:24 2009
New Revision: 196661
URL: http://svn.freebsd.org/changeset/base/196661
Log:
add core dump support to blkfront
Obtained from: Frank Suchomel
Modified:
head/sys/dev/xen/blkfront/blkfront.c
Modified: head/sys/dev/xen/blkfront/blkfront.c
==============================================================================
--- head/sys/dev/xen/blkfront/blkfront.c Sun Aug 30 19:40:09 2009
(r196660)
+++ head/sys/dev/xen/blkfront/blkfront.c Sun Aug 30 20:45:24 2009
(r196661)
@@ -16,7 +16,9 @@
*/
/*
- * XenoBSD block device driver
+ * XenBSD block device driver
+ *
+ * Copyright (c) 2009 Frank Suchomel, Citrix
*/
#include <sys/cdefs.h>
@@ -122,6 +124,10 @@ static int blkif_ioctl(struct disk *dp,
static int blkif_queue_request(struct bio *bp);
static void xb_strategy(struct bio *bp);
+// In order to quiesce the device during kernel dumps, outstanding requests to
+// DOM0 for disk reads/writes need to be accounted for.
+static int blkif_queued_requests;
+static int xb_dump(void *, void *, vm_offset_t, off_t, size_t);
/* XXX move to xb_vbd.c when VBD update support is added */
@@ -231,6 +237,7 @@ xlvbd_add(device_t dev, blkif_sector_t c
sc->xb_disk->d_close = blkif_close;
sc->xb_disk->d_ioctl = blkif_ioctl;
sc->xb_disk->d_strategy = xb_strategy;
+ sc->xb_disk->d_dump = xb_dump;
sc->xb_disk->d_name = name;
sc->xb_disk->d_drv1 = sc;
sc->xb_disk->d_sectorsize = sector_size;
@@ -286,9 +293,10 @@ xb_strategy(struct bio *bp)
* Place it in the queue of disk activities for this disk
*/
mtx_lock(&blkif_io_lock);
- bioq_disksort(&sc->xb_bioq, bp);
+ bioq_disksort(&sc->xb_bioq, bp);
xb_startio(sc);
+
mtx_unlock(&blkif_io_lock);
return;
@@ -301,6 +309,81 @@ xb_strategy(struct bio *bp)
return;
}
+static void xb_quiesce(struct blkfront_info *info);
+// Quiesce the disk writes for a dump file before allowing the next buffer.
+static void
+xb_quiesce(struct blkfront_info *info)
+{
+ int mtd;
+
+ // While there are outstanding requests
+ while (blkif_queued_requests) {
+ RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, mtd);
+ if (mtd) {
+ // Recieved request completions, update queue.
+ blkif_int(info);
+ }
+ if (blkif_queued_requests) {
+ // Still pending requests, wait for the disk i/o to
complete
+ HYPERVISOR_block();
+ }
+ }
+}
+
+// Some bio structures for dumping core
+#define DUMP_BIO_NO 16 // 16 * 4KB = 64KB dump block
+static struct bio xb_dump_bp[DUMP_BIO_NO];
+
+// Kernel dump function for a paravirtualized disk device
+static int
+xb_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset,
+ size_t length)
+{
+ int sbp;
+ int mbp;
+ size_t chunk;
+ struct disk *dp = arg;
+ struct xb_softc *sc = (struct xb_softc *) dp->d_drv1;
+ int rc = 0;
+
+ xb_quiesce(sc->xb_info); // All quiet on the western
front.
+ if (length > 0) {
+ // If this lock is held, then this module is failing, and a
successful
+ // kernel dump is highly unlikely anyway.
+ mtx_lock(&blkif_io_lock);
+ // Split the 64KB block into 16 4KB blocks
+ for (sbp=0; length>0 && sbp<DUMP_BIO_NO; sbp++) {
+ chunk = length > PAGE_SIZE ? PAGE_SIZE : length;
+ xb_dump_bp[sbp].bio_disk = dp;
+ xb_dump_bp[sbp].bio_pblkno = offset / dp->d_sectorsize;
+ xb_dump_bp[sbp].bio_bcount = chunk;
+ xb_dump_bp[sbp].bio_resid = chunk;
+ xb_dump_bp[sbp].bio_data = virtual;
+ xb_dump_bp[sbp].bio_cmd = BIO_WRITE;
+ xb_dump_bp[sbp].bio_done = NULL;
+
+ bioq_disksort(&sc->xb_bioq, &xb_dump_bp[sbp]);
+
+ length -= chunk;
+ offset += chunk;
+ virtual = (char *) virtual + chunk;
+ }
+ // Tell DOM0 to do the I/O
+ xb_startio(sc);
+ mtx_unlock(&blkif_io_lock);
+
+ // Must wait for the completion: the dump routine reuses the
same
+ // 16 x 4KB buffer space.
+ xb_quiesce(sc->xb_info); // All quite on the eastern
front
+ // If there were any errors, bail out...
+ for (mbp=0; mbp<sbp; mbp++) {
+ if ((rc = xb_dump_bp[mbp].bio_error)) break;
+ }
+ }
+ return (rc);
+}
+
+
static int
blkfront_probe(device_t dev)
{
@@ -646,6 +729,7 @@ GET_ID_FROM_FREELIST(struct blkfront_inf
KASSERT(nfree <= BLK_RING_SIZE, ("free %lu > RING_SIZE", nfree));
info->shadow_free = info->shadow[nfree].req.id;
info->shadow[nfree].req.id = 0x0fffffee; /* debug */
+ atomic_add_int(&blkif_queued_requests, 1);
return nfree;
}
@@ -655,6 +739,7 @@ ADD_ID_TO_FREELIST(struct blkfront_info
info->shadow[id].req.id = info->shadow_free;
info->shadow[id].request = 0;
info->shadow_free = id;
+ atomic_subtract_int(&blkif_queued_requests, 1);
}
static inline void
_______________________________________________
svn-src-all@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
