freebsd-nq/sys/cddl
Andriy Gapon f6bb41924c zfs + sendfile: do not produce partially valid pages for vnode's tail
Since r212650 and before this change sendfile(2) could produce
a partially valid page for a trailing portion of a ZFS vnode.
vm_fault() always wants to see a fully valid page even if it's the last
page that partially extends beyond vnode's end.  Otherwise it calls
vop_getpages() to bring in the page.  In the case of ZFS this means
that the data is read from the page into the same page and this breaks
checks in ZFS mappedread() - a thread that set VPO_BUSY on the page in
vm_fault() will get blocked forever waiting for it to be cleared.

Many thanks to Kai and Jeremy for reproducing the issue and providing
important debugging information and help.

Reported by:	Kai Gallasch <gallasch@free.de>,
		Jeremy Chadwick <freebsd@jdc.parodius.com>
Tested by:	Kai Gallasch <gallasch@free.de>,
		Jeremy Chadwick <freebsd@jdc.parodius.com>
Reviewed by:	kib
MFC after:	3 days
To-Do:		apply the same treatment to tmpfs + sendfile
2010-10-12 17:04:21 +00:00
..
boot/zfs Forgot to commit this file. Add ZPOOL_CONFIG_IS_LOG. 2010-09-10 04:44:13 +00:00
compat/opensolaris opensolaris_kmem kmem_size(): report lesser of vm_kmem_size and available 2010-10-07 18:16:14 +00:00
contrib/opensolaris zfs + sendfile: do not produce partially valid pages for vnode's tail 2010-10-12 17:04:21 +00:00
dev Make the /dev/dtrace/helper node have the mode 0660. This allows 2010-09-01 12:08:32 +00:00