The algorithm for laying out new directories was devised in the 1980s
and markedly improved the performance of the filesystem. In those days
large disks had at most 100 cylinder groups and often as few as 10-20.
Modern multi-terrabyte disks have thousands of cylinder groups. The
original algorithm does not handle these large sizes well. This change
attempts to expand the scope of the original algorithm to work well
with these much larger disks while still retaining the properties
of the original algorithm for small disks.
The filesystem implementation is divided into policy routines and
implementation routines. The policy routines can be changed in any
way desired without risk of corrupting the filesystem. The policy
requests are handled by the implementation layer. If the policy
asks for an available resource, it is granted. But if it asks for
an already in-use resource, then the implementation will provide
an available one nearby the request. Thus it is impossible for a
policy to double allocate. This change is limited to the policy
implementation.
This change updates the ffs_dirpref() routine which is responsible
for selecting the cylinder group into which a new directory should
be placed. If we are near the root of the filesystem we aim to
spread them out as much as possible. As we descend deeper from the
root we cluster them closer together around their parent as we
expect them to be more closely interactive. Higher-level directories
like usr/src/sys and usr/src/bin should be separated while the
directories in these areas are more likely to be accessed together
so should be closer. And directories within commands or kernel
subsystems should be closer still.
We pick a range of cylinder groups around the cylinder group of the
directory in which we are being created. The size of the range for
our search is based on our depth from the root of our filesystem.
We then probe that range based on how many directories are already
present. The first new directory is at 1/2 (middle) of the range;
the second is in the first 1/4 of the range, then at 3/4, 1/8, 3/8,
5/8, 7/8, 1/16, 3/16, 5/16, etc.
It is desirable to store the depth of a directory in its on-disk
inode so that it is available when we need it. We add a new field
di_dirdepth to track the depth of each directory. Because there are
few spare fields left in the inode, we choose to share an existing
field in the inode rather than having one of our own. Specifically
we create a union with the di_freelink field. The di_freelink field
is used to track inodes that have been unlinked but remain referenced.
It is not needed until a rmdir(2) operation has been done on a
directory. At that point, the directory has no contents and even
if it is kept active as a current directory is no longer able to
have any new directories or files created in it. Thus the use of
di_dirdepth and di_freelink will never coincide.
Reported by: Timo Voelker
Reviewed by: kib
Tested by: Peter Holm
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D39246
If a directory entry has an illegal inode number (less than zero
or greater than the last inode in the filesystem) the entry is removed.
If a directory '.' or '..' entry had an illegal inode number they
were being removed. Since fsck_ffs knows what the correct value is
for these two entries fix them rather deleting them.
Add much more extensive cylinder group checks and use them to be
more careful about rebuilding a cylinder group.
Check for out-of-range block numbers before trying to free them.
When a directory is deleted also remove its cache entry created
in pass1 so that later passes do not try to operate on a deleted
directory.
Check for ctime(3) returning NULL before trying to use its return.
When freeing a directory inode, do not try to interpret it as a
directory.
Reserve space in the inostatlist to have room to allocate a
lost+found directory.
If an invalid block number is found past the end of an inode simply
remove it rather than clearing and removing the inode.
Modernize the inoinfo structure to use queue(3) LIST rather than a
handrolled linked list implementation.
Reported by: Bob Prohaska, John-Mark Gurney, and Mark Millard
Tested by: Peter Holm
Reviewed by: Peter Holm
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D38668
The UFS filesystem expects to find '.' and '..' as the first two entries
in a directory. The kernel's UFS name cache can become quite confused
when these two entries are not present as the first two entries.
Prior to this change, when the fsck_ffs(8) utility detected that
'.' and/or '..' were missing, it would report them, but only offered
to replace them if the space at the beginning of the directory was
available. Otherwise it was left to the system administrator to
move the offending file(s) out of the way and then rerun fsck_ffs(8)
to create the '.' and '..' entries.
With this change, fsck_ffs(8) will always be able to create the '.'
and/or '..' entries. It moves any files in the way elsewhere in the
directory block. If there is no room in the directory block to which
to move them, they are placed in the lost+found directory.
Reported by: Peter Holm
Sponsored by: The FreeBSD Foundation
making fsck_ffs(8) run faster, there should be no functional change.
The original fsck_ffs(8) had its own disk I/O management system.
When gjournal(8) was added to FreeBSD 7, code was added to fsck_ffs(8)
to do the necessary gjournal rollback. Rather than use the existing
fsck_ffs(8) disk I/O system, it wrote its own from scratch. Similarly
when journalled soft updates were added in FreeBSD 9, code was added
to fsck_ffs(8) to do the necessary journal rollback. And once again,
rather than using either of the existing fsck_ffs(8) disk I/O
systems, it wrote its own from scratch. Lastly the fsdb(8) utility
uses the fsck_ffs(8) disk I/O management system. In preparation for
making the changes necessary to enable snapshots to be taken when
using journalled soft updates, it was necessary to have a single
disk I/O system used by all the various subsystems in fsck_ffs(8).
This commit merges the functionality required by all the different
subsystems into a single disk I/O system that supports all of their
needs. In so doing it picks up optimizations from each of them
with the results that each of the subsystems does fewer reads and
writes than it did with its own customized I/O system. It also
greatly simplifies making changes to fsck_ffs(8) since everything
goes through a single place. For example the ginode() function
fetches an inode from the disk. When inode check hashes were added,
they previously had to be checked in the code implementing inode
fetch in each of the three different disk I/O systems. Now they
need only be checked in ginode().
Tested by: Peter Holm
Sponsored by: Netflix
Followup to r313780. Also prefix ext2's and nandfs's versions with
EXT2_ and NANDFS_.
Reported by: kib
Reviewed by: kib, mckusick
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D9623
Mainly focus on files that use BSD 3-Clause license.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
The index() and rindex() functions were marked LEGACY in the 2001
revision of POSIX and were subsequently removed from the 2008 revision.
The strchr() and strrchr() functions are part of the C standard.
This makes the source code a lot more consistent, as most of these C
files also call into other str*() routines. In fact, about a dozen
already perform strchr() calls.
in background mode to correct expected inconsistencies that arise
during directory rename (see immediately previous update to this
file for details). If run on a kernel without the new functionality,
background fsck will simply ignore these inconsistencies rather
than fail.
Reported by: jeff
states. First its new name will be created causing it to have two
names (from possibly different parents). Next, if it has different
parents, its value of ".." will be changed from pointing to the old
parent to pointing to the new parent. Concurrently, its old name
will be removed bringing it back into a consistent state. When fsck
encounters an extra name for a directory, it offers to remove the
"extraneous hard link"; when it finds that the names have been
changed but the update to ".." has not happened, it offers to rewrite
".." to point at the correct parent. Both of these changes were
considered unexpected so would cause fsck in preen mode or fsck in
background mode to fail with the need to run fsck manually to fix
these problems.
This update changes these errors to be expected so that in preen
mode fsck will simply fix these transitional errors. For now,
background fsck will note these errors, but will need additional
kernel support to fix them, so will simply ignore them rather than
fail. A future update will allow background fsck to fix these
problems.
Reported by: jeff
processing the information. chk1 is more prone to crash when insane
information is provided by the on-disk inode, and does not even work
if the inode is being smarshed badly.
count of zero and instead encode this information in the inode state.
Pass 4 performed a linear search of this list for each inode in
the file system, which performs poorly if the list is long.
Reviewed by: sam & keramida (an earlier version of the patch), mckusick
MFC after: 1 month
filesystem expands the inode to 256 bytes to make space for 64-bit
block pointers. It also adds a file-creation time field, an ability
to use jumbo blocks per inode to allow extent like pointer density,
and space for extended attributes (up to twice the filesystem block
size worth of attributes, e.g., on a 16K filesystem, there is space
for 32K of attributes). UFS2 fully supports and runs existing UFS1
filesystems. New filesystems built using newfs can be built in either
UFS1 or UFS2 format using the -O option. In this commit UFS1 is
the default format, so if you want to build UFS2 format filesystems,
you must specify -O 2. This default will be changed to UFS2 when
UFS2 proves itself to be stable. In this commit the boot code for
reading UFS2 filesystems is not compiled (see /sys/boot/common/ufsread.c)
as there is insufficient space in the boot block. Once the size of the
boot block is increased, this code can be defined.
Things to note: the definition of SBSIZE has changed to SBLOCKSIZE.
The header file <ufs/ufs/dinode.h> must be included before
<ufs/ffs/fs.h> so as to get the definitions of ufs2_daddr_t and
ufs_lbn_t.
Still TODO:
Verify that the first level bootstraps work for all the architectures.
Convert the utility ffsinfo to understand UFS2 and test growfs.
Add support for the extended attribute storage. Update soft updates
to ensure integrity of extended attribute storage. Switch the
current extended attribute interfaces to use the extended attribute
storage. Add the extent like functionality (framework is there,
but is currently never used).
Sponsored by: DARPA & NAI Labs.
Reviewed by: Poul-Henning Kamp <phk@freebsd.org>
It does not help modern compilers, and some may take some hit from it.
(I also found several functions that listed *every* of its 10 local vars with
"register" -- just how many free registers do people think machines have?)
These were mainly missing casts or wrong format strings in printf
statements, but there were also missing includes, unused variables,
functions and arguments.
The choice of `long' vs `int' still seems almost random in a lot
of places though.
directory is encountered. This includes the full path of the
directory that will be removed if the user answers "y" to the
"REMOVE?" question.
PR: bin/226851
Submitted by: KOIE Hide <hide@koie.org>
MFC after: 1 week
affect current systems until fsck is modified to use these new
facilities. To try out this change, set the fsck passno to zero
in /etc/fstab to cause the filesystem to be mounted without running
fsck, then run `fsck_ffs -p -B <filesystem>' after the system has
been brought up multiuser to run a background cleanup on <filesystem>.
Note that the <filesystem> in question must have soft updates enabled.
a SIGINFO (normally via Ctrl-T), a line will be output indicating
the current phase number and progress information relevant to the
current phase.
Approved by: mckusick
Submitted by: Kirk McKusick <mckusick@McKusick.COM>
Obtained from: Mckusick, BSDI and a host of others
This exactly matches Kirks sources imported under the
Tag MCKUSICK2. These are as supplied by kirk with one small
change needed to compile under freeBSD.
Some FreeBSD patches will be added back, though many have been
added to Kirk's sources already.