Patch Name: PHKL_20411

Patch Description: s700_800 11.00 Adv VxFS snapshot filesystem fixes

Creation Date: 99/11/08

Post Date:  99/11/12

Hardware Platforms - OS Releases:
	s700: 11.00
	s800: 11.00

Products:
	HP OnLineJFS (Advanced VxFS) B.11.00

Filesets:
	AdvJournalFS.VXFS-ADV-KRN,fr=B.11.00,fa=HP-UX_B.11.00_32,v=HP
	AdvJournalFS.VXFS-ADV-KRN,fr=B.11.00,fa=HP-UX_B.11.00_64,v=HP

Automatic Reboot?: Yes

Status: General Release

Critical:
	Yes
	PHKL_20411: HANG
	PHKL_18532: PANIC
	PHKL_16206: HANG

Category Tags:
	defect_repair general_release critical panic halts_system

Path Name: /hp-ux_patches/s700_800/11.X/PHKL_20411

Symptoms:
	PHKL_20411:
	( SR: 8606100400 DTS: JAGab31753 )
	VxFS snapshot may hang. The chances of hitting this
	problem is remote.  When this happens threads hang
	sleeping on busy reserved snapshot copy buffers.

	PHKL_18532:
	System using VxFS snapshot panics with a non-access
	data TLB miss. The stack trace looks like:

	panic+0x14 report_trap_or_int_and_panic+0x80 trap+0xe08
	nokgdb+0x8 epic_map_dma_context+0x98
	epic_map_dma_buffer+0x150 dma_setup+0x120
	c720_if_start+0x178 scsi_strategy_real+0x3c4
	pa_ioforw_sched+0x254 scsi_strategy+0xd4
	pa_ioforw_sched+0x254 scsi_strategy+0xd4 lv_startpv+0x1a4
	lv_begin+0x128 lv_schedule+0x4e0 lv_initiate+0x198
	lv_strategy+0x208 vx_dev_strategy+0x170
	vx_snap_bpcopy+0x260 vx_snap_copyblk+0x140
	vx_snap_copy+0x50 vx_dio_chain_start+0xa4
	vx_dio_iovec+0x5d0 vx_dio_rdwri+0x14c
	vx_dio_writei+0x8c vx_write1+0xcfc
	vx_rdwr+0x330 vno_rw+0xa0 write+0x104 syscall+0x5cc
	$syscallrtn+0x0

	PHKL_16206:
	Vxdump hangs while backing up a JFS snapshot system,
	causing the system tohang eventualy.

Defect Description:
	PHKL_20411:
	( SR: 8606100400 DTS: JAGab31753 )

	This is a bug in the VxFS snapshot code.  For copying
	blocks to the snapshot device, vx_getblk() is called to
	return a buffer without waiting.  If no buffer is returned,
	buffers from reserved copy buffer for the file system are
	used. If the reserved buffer is busy, the thread will be
	put to sleep on the buffer but never woken up. This is
	because the VX_COPYBUF_LOCK macro sets the b_wanted field
	of the reserved buffer while VX_COPYBUF_UNLOCK only tests
	the B_WANTED flag in b_flags. The two macros were not
	in sync.

	Resolution:
	Check buffer b_wanted also in VX_COPYBUF_UNLOCK.

	PHKL_18532:
	When multiple fragments of the buffer passed to
	vx_snap_bpcopy() are written (rather than the entire
	buffer), vx_snap_bpcopy() incorrectly calculates the
	offset into the buffer of the second and subsequent
	fragments. Copying data beyond the valid address
	range results non-access data TLB miss.

	Resolution:
	The fix is to use the correct buffer address and
	offset from that.

	PHKL_16206:
	When multiple processes read fron the same JFS snapshot
	file system, a deadlock situation occurred in
	vx_snap_read() where one process holding a snapshot
	bitmap buffer was waiting for a shapshot structure lock
	while the process owning the shapshot structure lock was
	sleeping for the bitmap buffer.  THe fix was to release
	the snapshot bitmap buffer properly to avoid the deadlock.

SR:
	4701368415 4701425090 8606100400

Patch Files:
	
	AdvJournalFS.VXFS-ADV-KRN,fr=B.11.00,fa=HP-UX_B.11.00_32,
		v=HP:
	/usr/conf/lib/libvxfs_adv.a(vx_snap.o)

	AdvJournalFS.VXFS-ADV-KRN,fr=B.11.00,fa=HP-UX_B.11.00_64,
		v=HP:
	/usr/conf/lib/libvxfs_adv.a(vx_snap.o)

what(1) Output:
	
	AdvJournalFS.VXFS-ADV-KRN,fr=B.11.00,fa=HP-UX_B.11.00_32,
		v=HP:
	/usr/conf/lib/libvxfs_adv.a(vx_snap.o):
		vx_snap.c $Date: 1999/11/08 10:16:56 $Revision: r11r
			os/5 PATCH_11.00 (PHKL_20411)

	AdvJournalFS.VXFS-ADV-KRN,fr=B.11.00,fa=HP-UX_B.11.00_64,
		v=HP:
	/usr/conf/lib/libvxfs_adv.a(vx_snap.o):
		vx_snap.c $Date: 1999/11/08 10:16:56 $Revision: r11r
			os/5 PATCH_11.00 (PHKL_20411)

cksum(1) Output:
	
	AdvJournalFS.VXFS-ADV-KRN,fr=B.11.00,fa=HP-UX_B.11.00_32,
		v=HP:
	3621142625 13432 /usr/conf/lib/libvxfs_adv.a(vx_snap.o)

	AdvJournalFS.VXFS-ADV-KRN,fr=B.11.00,fa=HP-UX_B.11.00_64,
		v=HP:
	359592478 27760 /usr/conf/lib/libvxfs_adv.a(vx_snap.o)

Patch Conflicts: None

Patch Dependencies: None

Hardware Dependencies: None

Other Dependencies: None

Supersedes:
	PHKL_18532 PHKL_16206

Equivalent Patches:
	PHKL_20357:
	s700: 10.20

	PHKL_20358:
	s800: 10.20

Patch Package Size: 70 KBytes

Installation Instructions:
	Please review all instructions and the Hewlett-Packard
	SupportLine User Guide or your Hewlett-Packard support terms
	and conditions for precautions, scope of license,
	restrictions, and, limitation of liability and warranties,
	before installing this patch.
	------------------------------------------------------------
	1. Back up your system before installing a patch.

	2. Login as root.

	3. Copy the patch to the /tmp directory.

	4. Move to the /tmp directory and unshar the patch:

		cd /tmp
		sh PHKL_20411

	5. Run swinstall to install the patch:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -s /tmp/PHKL_20411.depot

	By default swinstall will archive the original software in 
	/var/adm/sw/save/PHKL_20411.  If you do not wish to retain a
	copy of the original software, use the patch_save_files option:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -x patch_save_files=false -s /tmp/PHKL_20411.depot

	WARNING: If patch_save_files is false when a patch is installed,
		 the patch cannot be deinstalled.  Please be careful
		 when using this feature.

	For future reference, the contents of the PHKL_20411.text file is 
	available in the product readme:

		swlist -l product -a readme -d @ /tmp/PHKL_20411.depot

	To put this patch on a magnetic tape and install from the
	tape drive, use the command:

		dd if=/tmp/PHKL_20411.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions: None