CVS commit: src/lib

["Emmanuel Dreyfus" <manu%netbsd.org@localhost>]

Module Name:    src
Committed By:   manu
Date:           Thu Aug 16 09:25:44 UTC 2012

Modified Files:
        src/lib/libp2k: p2k.c
        src/lib/libpuffs: dispatcher.c pnode.c puffs.3 puffs.h puffs_ops.3

Log Message:
Fix regression that has been introduced when the lookup/reclaim race
condition was addressed in libpuffs by counting lookups.

The fix assumes that cookies map to struct puffs_cookie, which has not
been documented as a requirement for filesystems using libpuffs. As an
example, we got burnt by this assumption in libp2k (kern/46734), and
we fixed bit by actually mapping libp2k cookies to struct puffs_node.

It is unlikely, but there may be third party filesystems that use cookies
unmapped to struct puffs_node, and they were left broken for now.

- we introduce a puffs_init() flag PUFFS_FLAG_PNCOOKIE that let filesystems
inform libpuffs that they map cookies to struct puffs_node. Is that flag
is used, the lookup/reclaim race condition fix is enabled. We enable the
flag for libp2k.

- filesystems that use puffs_pn_new() obviouslty use struct puffs_node
and gain PUFFS_FLAG_PNCOOKIE automatically even if they did not specify
it in puffs_init(). This include all our PUFFS filesystem in-tree except
libp2k.

- for filesystems not willing to use struct puffs_node, we introduce a
reclaim2 vnop, which is reclaim with an additionnal lookup count argument.
This vnop let the filesystem implement the lookup/reclaim race fix on
its own.


To generate a diff of this commit:
cvs rdiff -u -r1.56 -r1.57 src/lib/libp2k/p2k.c
cvs rdiff -u -r1.43 -r1.44 src/lib/libpuffs/dispatcher.c
cvs rdiff -u -r1.12 -r1.13 src/lib/libpuffs/pnode.c
cvs rdiff -u -r1.55 -r1.56 src/lib/libpuffs/puffs.3
cvs rdiff -u -r1.123 -r1.124 src/lib/libpuffs/puffs.h
cvs rdiff -u -r1.34 -r1.35 src/lib/libpuffs/puffs_ops.3

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.