document the libufs interface for fetching and storing inodes.
The undocumented getino / putino interface has been replaced
with a new getinode / putinode interface.
Convert the utilities that had been using the undocumented
interface to use the new documented interface.
No functional change (as for now the libufs library does not
do inode check-hashes).
Reviewed by: kib
Tested by: Peter Holm
Sponsored by: Netflix
Specifically reading is done if ffs_sbget() and writing is done
in ffs_sbput(). These functions are exported to libufs via the
sbget() and sbput() functions which then used in the various
filesystem utilities. This work is in preparation for adding
subperblock check hashes.
No functional change intended.
Reviewed by: kib
check-hash after making changes to the cylinder group. The problem
was that the journal-recovery code was calling the libufs bwrite()
function instead of the cgput() function. The cgput() function updates
the cylinder-group check-hash before writing the cylinder group.
This change required the additions of the cgget() and cgput() functions
to the libufs API to avoid a gratuitous bcopy of every cylinder group
to be read or written. These new functions have been added to the
libufs manual pages. This was the first opportunity that I have had
to use and document the use of the EDOOFUS error code.
Reviewed by: kib
Reported by: emaste and others
check hash to cylinder groups. If a check hash fails when a cylinder
group is read, no further allocations are attempted in that cylinder
group until it has been fixed by fsck. This avoids a class of
filesystem panics related to corrupted cylinder group maps. The
hash is done using crc32c.
Check hases are added only to UFS2 and not to UFS1 as UFS1 is primarily
used in embedded systems with small memories and low-powered processors
which need as light-weight a filesystem as possible.
Specifics of the changes:
sys/sys/buf.h:
Add BX_FSPRIV to reserve a set of eight b_xflags that may be used
by individual filesystems for their own purpose. Their specific
definitions are found in the header files for each filesystem
that uses them. Also add fields to struct buf as noted below.
sys/kern/vfs_bio.c:
It is only necessary to compute a check hash for a cylinder
group when it is actually read from disk. When calling bread,
you do not know whether the buffer was found in the cache or
read. So a new flag (GB_CKHASH) and a pointer to a function to
perform the hash has been added to breadn_flags to say that the
function should be called to calculate a hash if the data has
been read. The check hash is placed in b_ckhash and the B_CKHASH
flag is set to indicate that a read was done and a check hash
calculated. Though a rather elaborate mechanism, it should
also work for check hashing other metadata in the future. A
kernel internal API change was to change breada into a static
fucntion and add flags and a function pointer to a check-hash
function.
sys/ufs/ffs/fs.h:
Add flags for types of check hashes; stored in a new word in the
superblock. Define corresponding BX_ flags for the different types
of check hashes. Add a check hash word in the cylinder group.
sys/ufs/ffs/ffs_alloc.c:
In ffs_getcg do the dance with breadn_flags to get a check hash and
if one is provided, check it.
sys/ufs/ffs/ffs_vfsops.c:
Copy across the BX_FFSTYPES flags in background writes.
Update the check hash when writing out buffers that need them.
sys/ufs/ffs/ffs_snapshot.c:
Recompute check hash when updating snapshot cylinder groups.
sys/libkern/crc32.c:
lib/libufs/Makefile:
lib/libufs/libufs.h:
lib/libufs/cgroup.c:
Include libkern/crc32.c in libufs and use it to compute check
hashes when updating cylinder groups.
Four utilities are affected:
sbin/newfs/mkfs.c:
Add the check hashes when building the cylinder groups.
sbin/fsck_ffs/fsck.h:
sbin/fsck_ffs/fsutil.c:
Verify and update check hashes when checking and writing cylinder groups.
sbin/fsck_ffs/pass5.c:
Offer to add check hashes to existing filesystems.
Precompute check hashes when rebuilding cylinder group
(although this will be done when it is written in fsutil.c
it is necessary to do it early before comparing with the old
cylinder group)
sbin/dumpfs/dumpfs.c
Print out the new check hash flag(s)
sbin/fsdb/Makefile:
Needs to add libufs now used by pass5.c imported from fsck_ffs.
Reviewed by: kib
Tested by: Peter Holm (pho)
brings in support for an optional intent log which eliminates the need
for background fsck on unclean shutdown.
Sponsored by: iXsystems, Yahoo!, and Juniper.
With help from: McKusick and Peter Holm
Similar to libexec/, do the same with lib/. Make WARNS=6 the norm and
lower it when needed.
I'm setting WARNS?=0 for secure/. It seems secure/ includes the
Makefile.inc provided by lib/. I'm not going to touch that directory.
Most of the code there is contributed anyway.
binaries in /bin and /sbin installed in /lib. Only the versioned files
reside in /lib, the .so symlink continues to live /usr/lib so the
toolchain doesn't need to be modified.
getino(3)/putino(3), inode.c has been reworked in Perforce to the point
where a manual page may not be accurate. Certainly putino(3) has not
even been merged back yet.
These will need a lot of improvement for most applications, but they
document the API enough to get someone on their feet, most likely. The
best documentation still exists in the form of libufs(3) consumers in the
base system.
the build. It is here to compartmentalise functionality currently duplicated
in many notable programs in the base system. It currently handles block
reads and writes, as well as reading and writing of the filesystem superblock,
and the reading/lookup of inode data. It supports both UFS and UFS2. I
will be maintaining it, and porting programs to use it, however for now, it
is simply being built as part of world.
