backing file per attribute type indexed by inode number to hold the extended
attributes.
This is working pretty well on my test systems, except for the "autostart"
feature. I need someone with a better handle on the VFS locking protocol
to go over that.
This is a work-in-progress. There are parts of this that could be re-factored
allowing this approach to be used on other types of file systems.
Adapted from FreeBSD.
- Ffs internal snapshots get compiled in unconditionally.
- File system snapshot device fss(4) added to all kernel configs that
have a disk. Device is commented out on all non-GENERIC kernels.
Reviewed by: Jason Thorpe <thorpej@netbsd.org>
directories are created on the fly and used to increase
performance by circumventing ufs_lookup's linear search.
Dirhash is enabled by the UFS_DIRHASH option, but not
by default.
- 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>
This is the bulk of PR #17345
The general approach is to use a run time deteriminable value
for DIRBLKSIZ. Additional allowances are included for using
MAXSYMLINKLEN with FS_42INODEFMT and a shift in the cylinder group
cluster summary count array. Support is added for managing
the Apple UFS volume label.
