_NETBSD_SOURCE as this makes cross building from older/newer versions of
NetBSD harder, not easier (and also makes the resulting tools 'different')
Wrap all required code with the inclusion of nbtool_config.h, attempt to
only use POSIX code in all places (or when reasonable test w. configure and
provide definitions: ala u_int, etc).
Reviewed by lukem. Tested on FreeBSD 4.9, Redhat Linux ES3, NetBSD 1.6.2 x86
NetBSD current (x86 and amd64) and Solaris 9.
Fixes PR's: PR#17762 PR#25944
doing copy-on-write.
- Change VFS_SNAPSHOT() to return the snapshot vnode locked.
- Make the IO path for copy-on-write and snapshot-read more lightweight.
Avoids deadlocks where vn_rdwr(...READ...) has a shared lock and needs
to copy-on-write.
Avoids deadlocks/panics where to clean pages the copy-on-write needs
to allocate pages for its VOP_PUTPAGES().
L_COWINPROGRESS part approved by: Jason R. Thorpe <thorpej@netbsd.org>
as LK_SHARED, the VOP_ code (in all our existing file systems)
was implememted assuming exclusive locking. Use of LK_SHARED
is technically a bug and only works right for uni-processor and
big-lock SMP systems. Our current file systems will blow up
(probably quite subtlely) with LK_SHARED and fine-grained SMP
locking.
- Not enabled by default. Needs kernel option FFS_SNAPSHOT.
- Change parameters of ffs_blkfree.
- Let the copy-on-write functions return an error so spec_strategy
may fail if the copy-on-write fails.
- Change genfs_*lock*() to use vp->v_vnlock instead of &vp->v_lock.
- Add flag B_METAONLY to VOP_BALLOC to return indirect block buffer.
- Add a function ffs_checkfreefile needed for snapshot creation.
- Add special handling of snapshot files:
Snapshots may not be opened for writing and the attributes are read-only.
Use the mtime as the time this snapshot was taken.
Deny mtime updates for snapshot files.
- Add function transferlockers to transfer any waiting processes from
one lock to another.
- Add vfsop VFS_SNAPSHOT to take a snapshot and make it accessible through
a vnode.
- Add snapshot support to ls, fsck_ffs and dump.
Welcome to 2.0F.
Approved by: Jason R. Thorpe <thorpej@netbsd.org>
and don't install the (.a) library.
This is useful for "build only" helper libraries.
* Add some #{ [...] #} comments around large conditional statements.
