* Add lfs_balloc capability to the lfs library.
* Extend the Ifile if we run out of free inodes when creating lost+found.
* Don't roll forward if we have allocated a lost+found, to avoid
conflicts when adding new files in roll-forward.
* Make some messages slightly more verbose (e.g. include inode number,
and use pwarn() instead of printf() so the messages include the device
name when preening).
* Change superblock detection/avoidance to use the offset table in the
primary superblock, rather than looking at the contents.
* Be more verbose about various operations when passed the -d flag,
especially roll-forward.
* Be more careful about dirops during roll forward, since the cleaner can
sometimes write blocks from dirop vnodes. Detect and avoid this problem.
* Always check the free list, even if given -i; if we're going to write
it we have to check it first.
* Mark inodes dirty when blocks are found during roll forward, so the
inodes are written with the new block locations.
* Update size of inodes if blocks beyond EOF are found during roll
forward.
* Fix segment accounting for blocks and inodes found during roll
forward.
* Report statistics on roll forward: how many new/deleted/moved files
and how many updated blocks (or "nothing new").
* Don't care if the device being checked is really a device, if we have
been passed the -f flag (to facilitate automated testing).
* When writing to the disk, use the current time in the segment headers
rathern than time 0.
* When passed the -i flag, locate the partial segment containing the
Ifile inode and use that to calculate lfs_offset, lfs_curseg,
lfs_nextseg. (Again for automated testing.)
64 bit block pointers, extended attribute storage, and a few
other things.
This commit does not yet include the code to manipulate the extended
storage (for e.g. ACLs), this will be done later.
Originally written by Kirk McKusick and Network Associates Laboratories for
FreeBSD.
(there are still some details to work out) but expect that to go
away soon. To support these basic changes (creation of lfs_putpages,
lfs_gop_write, mods to lfs_balloc) several other changes were made, to
wit:
* Create a writer daemon kernel thread whose purpose is to handle page
writes for the pagedaemon, but which also takes over some of the
functions of lfs_check(). This thread is started the first time an
LFS is mounted.
* Add a "flags" parameter to GOP_SIZE. Current values are
GOP_SIZE_READ, meaning that the call should return the size of the
in-core version of the file, and GOP_SIZE_WRITE, meaning that it
should return the on-disk size. One of GOP_SIZE_READ or
GOP_SIZE_WRITE must be specified.
* Instead of using malloc(...M_WAITOK) for everything, reserve enough
resources to get by and use malloc(...M_NOWAIT), using the reserves if
necessary. Use the pool subsystem for structures small enough that
this is feasible. This also obsoletes LFS_THROTTLE.
And a few that are not strictly necessary:
* Moves the LFS inode extensions off onto a separately allocated
structure; getting closer to LFS as an LKM. "Welcome to 1.6O."
* Unified GOP_ALLOC between FFS and LFS.
* Update LFS copyright headers to correct values.
* Actually cast to unsigned in lfs_shellsort, like the comment says.
* Keep track of which segments were empty before the previous
checkpoint; any segments that pass two checkpoints both dirty and
empty can be summarily cleaned. Do this. Right now lfs_segclean
still works, but this should be turned into an effectless
compatibility syscall.
Kernels and tools understand both v1 and v2 filesystems; newfs_lfs
generates v2 by default. Changes for the v2 layout include:
- Segments of non-PO2 size and arbitrary block offset, so these can be
matched to convenient physical characteristics of the partition (e.g.,
stripe or track size and offset).
- Address by fragment instead of by disk sector, paving the way for
non-512-byte-sector devices. In theory fragments can be as large
as you like, though in reality they must be smaller than MAXBSIZE in size.
- Use serial number and filesystem identifier to ensure that roll-forward
doesn't get old data and think it's new. Roll-forward is enabled for
v2 filesystems, though not for v1 filesystems by default.
- The inode free list is now a tailq, paving the way for undelete (undelete
is not yet implemented, but can be without further non-backwards-compatible
changes to disk structures).
- Inode atime information is kept in the Ifile, instead of on the inode;
that is, the inode is never written *just* because atime was changed.
Because of this the inodes remain near the file data on the disk, rather
than wandering all over as the disk is read repeatedly. This speeds up
repeated reads by a small but noticeable amount.
Other changes of note include:
- The ifile written by newfs_lfs can now be of arbitrary length, it is no
longer restricted to a single indirect block.
- Fixed an old bug where ctime was changed every time a vnode was created.
I need to look more closely to make sure that the times are only updated
during write(2) and friends, not after-the-fact during a segment write,
and certainly not by the cleaner.
(though still not all) errors in a damaged lfs. Segment byte accounting
is corrected in pass 5. "fsck_lfs -p" will do a partial roll-forward,
verifying the checkpoint from the newer superblock. fscknames[] is
updated so that fsck knows about fsck_lfs.
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