and isn't strictly required. However, it lowers the number of false
positives found when grep'ing the kernel sources for p_ucred to ensure
proper locking.
Remove bowrite(), it is now unused.
This is the first step in getting entirely rid of BIO_ORDERED which is
a generally accepted evil thing.
Approved by: mckusick
The use of the zone allocator may or may not be overkill.
There is an XXX: over in ufs/ufs/ufs_vnops.c that jlemon may need
to revisit.
This shaves about 60 bytes of struct vnode which on my laptop means
600k less RAM used for vnodes.
o Modify the system call syntax for extattr_{get,set}_{fd,file}() so
as not to use the scatter gather API (which appeared not to be used
by any consumers, and be less portable), rather, accepts 'data'
and 'nbytes' in the style of other simple read/write interfaces.
This changes the API and ABI.
o Modify system call semantics so that extattr_get_{fd,file}() return
a size_t. When performing a read, the number of bytes read will
be returned, unless the data pointer is NULL, in which case the
number of bytes of data are returned. This changes the API only.
o Modify the VOP_GETEXTATTR() vnode operation to accept a *size_t
argument so as to return the size, if desirable. If set to NULL,
the size will not be returned.
o Update various filesystems (pseodofs, ufs) to DTRT.
These changes should make extended attributes more useful and more
portable. More commits to rebuild the system call files, as well
as update userland utilities to follow.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
inode'' panic. This change corrects that problem by setting the
fs_active flag when the inode map changes to notify the snapshot
code that the cylinder group must be rescanned.
Submitted by: Robert Watson <rwatson@FreeBSD.org>
without being reclaimed. This bug was introduced in revision 1.95
dealing with filenames placed in newly allocated directory blocks,
thus is not present in 4.X systems. The bug is triggered when a
new entry is made in a directory after the data block containing
the original new entry has been written, but before the inode
that references the data block has been written.
Submitted by: Bill Fenner <fenner@research.att.com>
been unlinked (e.g., with a zero link count). We have to expunge
all trace of these files from the snapshot so that they are neither
reclaimed prematurely by fsck nor saved unnecessarily by dump.
which small and/or nearly full filesystems would fail with `file
system full' messages when trying to replace a number of existing
files (for example during a system installation). When the allocation
routines are about to fail with a file system full condition, they
make a call to softdep_request_cleanup() which attempts to accelerate
the flushing of pending deletion requests in an effort to free up
space. In the face of filesystem I/O requests that exceed the
available disk transfer capacity, the cleanup request could take
an unbounded amount of time. Thus, the softdep_request_cleanup()
routine will only try for tickdelay seconds (default 2 seconds)
before giving up and returning a filesystem full error. Under typical
conditions, the softdep_request_cleanup() routine is able to free
up space in under fifty milliseconds.
which caused incomplete snapshots to be taken. When background
fsck would run on these snapshots, the result would be files
being incorrectly released which would subsequently panic the
kernel with ``handle_workitem_freefile: inodedep survived'',
``handle_written_inodeblock: live inodedep'', and
``handle_workitem_remove: lost inodedep'' errors.
involving file removal or file update were not always being fully
committed to disk. The result was lost files or corrupted file data.
This change ensures that the filesystem is properly synced to disk
before the filesystem is down-graded.
This delta also fixes a long standing bug in which a file open for
reading has been unlinked. When the last open reference to the file
is closed, the inode is reclaimed by the filesystem. Previously,
if the filesystem had been down-graded to read-only, the inode could
not be reclaimed, and thus was lost and had to be later recovered
by fsck. With this change, such files are found at the time of the
down-grade. Normally they will result in the filesystem down-grade
failing with `device busy'. If a forcible down-grade is done, then
the affected files will be revoked causing the inode to be released
and the open file descriptors to begin failing on attempts to read.
Submitted by: "Sam Leffler" <sam@errno.com>
Seigo Tanimura (tanimura) posted the initial delta.
I've polished it quite a bit reducing the need for locking and
adapting it for KSE.
Locks:
1 mutex in each filedesc
protects all the fields.
protects "struct file" initialization, while a struct file
is being changed from &badfileops -> &pipeops or something
the filedesc should be locked.
1 mutex in each struct file
protects the refcount fields.
doesn't protect anything else.
the flags used for garbage collection have been moved to
f_gcflag which was the FILLER short, this doesn't need
locking because the garbage collection is a single threaded
container.
could likely be made to use a pool mutex.
1 sx lock for the global filelist.
struct file * fhold(struct file *fp);
/* increments reference count on a file */
struct file * fhold_locked(struct file *fp);
/* like fhold but expects file to locked */
struct file * ffind_hold(struct thread *, int fd);
/* finds the struct file in thread, adds one reference and
returns it unlocked */
struct file * ffind_lock(struct thread *, int fd);
/* ffind_hold, but returns file locked */
I still have to smp-safe the fget cruft, I'll get to that asap.
lost if some other process uses the lock while we are sleeping. We
restore it after we have slept. This functionality is provided by
a new routine interlocked_sleep() that wraps the interlocking with
functions that sleep. This function is then used in place of the
old ACQUIRE_LOCK_INTERLOCKED() and FREE_LOCK_INTERLOCKED() macros.
Submitted by: Debbie Chu <dchu@juniper.net>
in softdep_sync_metadata(). Otherwise we may miss dependencies
that need to be flushed which will result in a later panic
with the message ``vinvalbuf: dirty bufs''.
Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
MFC after: 1 week
been removed from the cache-list as part of a previous unmount.
This would result in panics (page fault in dqflush()) during subsequent
umounts provided that enough distinct UID's to actually make the
hash do something are active.
This can probably explain a number of weird quota related behaviours.
PR: 32331 maybe more.
Reproduced by: Søren Schrørder <sch@cybercity.dk>
against VM_WAIT in the pageout code. Both fixes involve adjusting
the lockmgr's timeout capability so locks obtained with timeouts do not
interfere with locks obtained without a timeout.
Hopefully MFC: before the 4.5 release
superblock that is already set up to handle pointer types. This
fixes an accidental change in the superblock size on 64-bit platforms
caused by revision 1.24.
when taking a snapshot. The two time consuming operations are
scanning all the filesystem bitmaps to determine which blocks
are in use and scanning all the other snapshots so as to be able
to expunge their blocks from the view of the current snapshot.
The bitmap scanning is broken into two passes. Before suspending
the filesystem all bitmaps are scanned. After the suspension,
those bitmaps that changed after being scanned the first time
are rescanned. Typically there are few bitmaps that need to be
rescanned. The expunging of other snapshots is now done after
the suspension is released by observing that we can easily
identify any blocks that were allocated to them after the
suspension (they will be maked as `not needing to be copied'
in the just created snapshot). For all the gory details, see
the ``Running fsck in the Background'' paper in the Usenix
BSDCon 2002 Conference Proceedings, pages 55-64.
new file end will land in the middle of a file hole. Since the last
block of a file must always be allocated, the hole is filled by
allocating a block at that location. If the hole being filled is
a direct block, then the truncation may eventually reduce the
full sized block down to a fragment. When running with soft
updates, it is necessary to FSYNC the file after allocating the
block and before creating the fragment to avoid triggering a
soft updates inconsistency when the block unexpectedly shrinks.
Found by: Matthew Dillon <dillon@apollo.backplane.com>
MFC after: 1 week
compare the slot offset against the predicted offset, not a boolean
flag. This typo effectively disabled the sequential optimisation,
but was otherwise harmless.
Not surprisingly, fixing this improves performance in the sequential
access case. I am seeing a 7% speedup on one machine here; using
dirhash when sequentially looking up directory entries is now about
5% faster instead of 2% slower than the non-dirhash case.
Submitted by: KOIE Hidetaka <koie@suri.co.jp>
MFC after: 1 week
in wdrain during a write. This flag needs to be used in devices whos
strategy routines turn-around and issue another high level I/O, such as
when MD turns around and issues a VOP_WRITE to vnode backing store, in order
to avoid deadlocking the dirty buffer draining code.
Remove a vprintf() warning from MD when the backing vnode is found to be
in-use. The syncer of buf_daemon could be flushing the backing vnode at
the time of an MD operation so the warning is not correct.
MFC after: 1 week
o Add reference to TrustedBSD Project in license header.
o Update dated comments, including comment in extattr.h claiming that
no file systems support extended attributes.
o Improve comment consistency.
coerces the deletion of a default ACL on a directory when no default
ACL EA is present to success. Because the UFS EA implementation doesn't
disinguish the EA failure modes "that EA name has not been
administratively enabled" from "that EA name has no defined data",
there's a potential conflict in error return values. Normally, the
lack of administratively configured EA support is coerced to
EOPNOTSUPP to indicate that ACLs are not available; in this case,
it is possible to get a successful return, even if ACLs are not
available because EA support for them has not been enabled.
Expand the comment in ufs_setacl() to identify this case.
Obtained from: TrustedBSD Project
from ufs_extattr_enable_with_open().
o Print auto-start notifications if (bootverbose). This was previously
commented out since it didn't know how to check for bootverbose.
o Drop in comments throughout indicating where ENOENT should be replaced
with ENOATTR once that is available.
Obtained from: TrustedBSD Project
implementation to replace single-character namespace prefixes, '$' is no
longer an invalid attribute name, and the namespace is relevant to
validity determination.
o Remove '$' case from ufs_extattr_valid_attrname()
o Add attrnamespace argument to ufs_extattr_valid_attrname(), and
fill out appropriately.
Currently no decisions are made based on the namespace argument, but
may be in the future.
Obtained from: TrustedBSD Project
real effect.
Optimize vfs_msync(). Avoid having to continually drop and re-obtain
mutexes when scanning the vnode list. Improves looping case by 500%.
Optimize ffs_sync(). Avoid having to continually drop and re-obtain
mutexes when scanning the vnode list. This makes a couple of assumptions,
which I believe are ok, in regards to vnode stability when the mount list
mutex is held. Improves looping case by 500%.
(more optimization work is needed on top of these fixes)
MFC after: 1 week
sanity check after every directory modification. This check can be
re-enabled at any time by setting the sysctl "vfs.ufs.dirhash_docheck"
to 1.
This group of sanity tests was there to ensure that any UFS_DIRHASH
bugs could be caught by a panic before a potentially corrupted
directory block would be written to disk. It has served its main
purpose now, so disable it in the interest of performance.
MFC after: 1 week
- crhold() returns a reference to the ucred whose refcount it bumps.
- crcopy() now simply copies the credentials from one credential to
another and has no return value.
- a new crshared() primitive is added which returns true if a ucred's
refcount is > 1 and false (0) otherwise.
because the IN_RENAME flag only fixes a few of the huge number of race
conditions that can result in the source path becoming invalid even
prior to the VOP_RENAME() call. The panics created a serious security
issue whereby an attacker could fairly easily cause the panic to
occur, crashing the machine.
The correct solution requires a great deal of work in the namei
path cache code.
MFC after: 0 days
first thought and may require serious work to the VOP_RENAME() api itself.
Basically, by the time the VOP_RENAME() function is called, it's already
too late.
- Move the SPECIAL_FLAG #define up next to the NOHOLDER #define and fix a
little nit that caused it to be defined as -(sizeof (struct thread) + 1)
instead of -2.
PRISON_ROOT to the suser_xxx() check. Since securelevels may now
be raised in specific jails, use of system flags can still be
restricted in jail(), but in a more configurable way.
o Users of jail() expecting system flags (such as schg) to restrict
jail()'s should be sure to set the securelevel appropriately in
jail()'s.
o This fixes activities involving automated system flag removal in
jail(), including installkernel and friends.
Obtained from: TrustedBSD Project
refering to securelevels; also, update the unprivileged process text
to better indicate the scope of actions permittable when any system
flags are already set (limited).
Submitted by: Udo Schweigert <udo.schweigert@siemens.com>
sizeof(struct inode) into a new malloc bucket on the i386. This
didn't happen in -current due to the removal of i_lock, but it does
no harm to apply the workaround to -current first.
Reduce the size of the i_spare[] array in struct inode from 4 to
3 entries, and change ext2fs to use i_din.di_spare[1] so that it
does not need i_spare[3].
Reviewed by: bde
MFC after: 3 days
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
an array "fs_contigdirs[]" to avoid too many directories getting
created in each cylinder group. The memory required for this and
two other arrays (fs_csp[] and fs_maxcluster[]) is allocated with
a single malloc() call, and divided up afterwards. However, the
'space' pointer is not advanced correctly, so fs_contigdirs and
fs_maxcluster end up pointing to the same address.
Add the missing code to advance the 'space' pointer, and remove
an unnecessary update of the pointer that follows.
This is likely to fix the "ffs_clusteralloc: map mismatch" panics
that have been reported recently.
Submitted by: Luke Mewburn <lukem@wasabisystems.com>
in got a bit broken, when ufs_extattr_stop() was called and failed,
ufs_extattr_destroy() would panic. This makes the call to destroy()
conditional on the success of stop().
Submitted by: Christian Carstensen <cc@devcon.net>
Obtained from: TrustedBSD Project
file. ffs will discard any pending dirty pages when it is closed,
so we may as well not waste time trying to clean them. This doesn't
stop other things from writing it out, eg: pageout, fsync(2) etc.
never attempt to hash directories once they are deleted. This fixes
a problem where operations on a deleted directory could trigger
dirhash sanity panics.
to supply the number of bytes to be bcopy()'d to move an entry. If
d_ino == 0 however, DIRSIZ() is not guaranteed to return a sensible
length, so ufs_direnter could end up corrupting a directory during
compaction. In practice I believe this can only happen after fsck_ffs
has fixed a previously-corrupted directory.
We now deal with any mid-block unused entries specially to avoid
using DIRSIZ() or bcopy() on such entries. We also ensure that the
variables 'dsize' and 'spacefree' contain meaningful values at all
times. Add a few comments to describe better this intricate piece
of code.
The special handling of mid-block unused entries makes the dirhash-
specific bugfix in the previous revision (1.53) now uncecessary,
so this change removes it.
Reviewed by: mckusick
that the directory entry was in use before attempting to find it
in the hash structures to change its offset. Normally, unused
entries do not need to be moved, but fsck can leave behind some
unused entries that do. A dirhash sanity panic resulted when the
entry to be moved was not found. Add a check that stops entries
with d_ino == 0 from being passed to ufsdirhash_move().
because it shares ufs code. In ufs_fhtovp(), the test on i_effnlink
is invalid because ext2fs does not maintain this field. In ufs_close(),
i_effnlink is also tested, to determines whether or not to call
vn_start_write(). The ufs_fhtovp issue breaks NFS exporting of
ext2fs filesystems; I believe the other is harmless.
Fix both cases by checking um_i_effnlink_valid in the ufsmount
struct, and use i_nlink if necessary.
Noticed by: bde
Reviewed by: mckusick, bde
entry (d_ino == 0) is found in a position that is not the start of
a DIRBLKSIZ block.
While such entries cannot occur normally (ufs always extends the
previous entry to cover the free space instead), they do not cause
problems and fsck does not fix them, so panicking is bad.
extra getblk/brelse sequence for each lookup. We already had this
buf in ufsdirhash_lookup(), so there was no point in brelse'ing it
only to have the caller immediately reaquire the same buffer.
This should make the case of sequential lookups marginally faster;
in my tests, sequential lookups with dirhash enabled are now only
around 1% slower than without dirhash.
directories. When enabled via "options UFS_DIRHASH", in-core hash
arrays are maintained for large directories. These allow all
directory operations to take place quickly instead of requiring
long linear searches. For now anyway, dirhash is not enabled by
default.
The in-core hash arrays have a memory requirement that is approximately
half the size of the size of the on-disk directory file. A number
of new sysctl variables allow control over which directories get
hashed and over the maximum amount of memory that dirhash will use:
vfs.ufs.dirhash_minsize
The minimum on-disk directory size for which hashing should be
used. The default is 2560 (2.5k).
vfs.ufs.dirhash_maxmem
The system-wide maximum total memory to be used by dirhash data
structures. The default is 2097152 (2MB).
The current amount of memory being used by dirhash is visible
through the read-only sysctl variable vfs.ufs.dirhash_maxmem.
Finally, some extra sanity checks that are enabled by default, but
which may have an impact on performance, can be disabled by setting
vfs.ufs.dirhash_docheck to 0.
Discussed on: -fs, -hackers
(this commit is just the first stage). Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to test in a more piecemeal
fashion. These macros will allow us to test fine-grained locks to a degree
before removing Giant, and also after, and to remove Giant in a piecemeal
fashion via sysctl's on those subsystems which the authors believe can
operate without Giant.
The symptom being treated in 1.98 was to avoid freeing a
pagedep dependency if there was still a newdirblk dependency
referencing it. That change is correct and no longer prints
a warning message when it occurs. The other part of revision
1.98 was to panic when a newdirblk dependency was encountered
during a file truncation. This fix removes that panic and
replaces it with code to find and delete the newdirblk
dependency so that the truncation can succeed.
true. This permits better interoperability with programs which register
filters on their stdin/stdout handles.
Submitted by: Niels Provos <provos@citi.umich.edu>
incorrect due to a missing check for some dependency. This change
avoids the freelist corruption (but not the temporarily inconsistent
state of the file system).
A message is printed as a reminder of the under lying problem when a
pagedep structure is not freed due to the NEWBLOCK flag being set.
Submitted by: Tor.Egge@fast.no
initialized on the file system before trying to grab the lock of the
per-mount extattr structure, as this lock is unitialized in that case.
This is needed because ufs_extattr_vnode_inactive is called from
ufs_inactive, which is also used by EA-unaware file systems such as
ext2fs.
Reviewed by: rwatson
real uid, saved uid, real gid, and saved gid to ucred, as well as the
pcred->pc_uidinfo, which was associated with the real uid, only rename
it to cr_ruidinfo so as not to conflict with cr_uidinfo, which
corresponds to the effective uid.
o Remove p_cred from struct proc; add p_ucred to struct proc, replacing
original macro that pointed.
p->p_ucred to p->p_cred->pc_ucred.
o Universally update code so that it makes use of ucred instead of pcred,
p->p_ucred instead of p->p_pcred, cr_ruidinfo instead of p_uidinfo,
cr_{r,sv}{u,g}id instead of p_*, etc.
o Remove pcred0 and its initialization from init_main.c; initialize
cr_ruidinfo there.
o Restruction many credential modification chunks to always crdup while
we figure out locking and optimizations; generally speaking, this
means moving to a structure like this:
newcred = crdup(oldcred);
...
p->p_ucred = newcred;
crfree(oldcred);
It's not race-free, but better than nothing. There are also races
in sys_process.c, all inter-process authorization, fork, exec, and
exit.
o Remove sigio->sio_ruid since sigio->sio_ucred now contains the ruid;
remove comments indicating that the old arrangement was a problem.
o Restructure exec1() a little to use newcred/oldcred arrangement, and
use improved uid management primitives.
o Clean up exit1() so as to do less work in credential cleanup due to
pcred removal.
o Clean up fork1() so as to do less work in credential cleanup and
allocation.
o Clean up ktrcanset() to take into account changes, and move to using
suser_xxx() instead of performing a direct uid==0 comparision.
o Improve commenting in various kern_prot.c credential modification
calls to better document current behavior. In a couple of places,
current behavior is a little questionable and we need to check
POSIX.1 to make sure it's "right". More commenting work still
remains to be done.
o Update credential management calls, such as crfree(), to take into
account new ruidinfo reference.
o Modify or add the following uid and gid helper routines:
change_euid()
change_egid()
change_ruid()
change_rgid()
change_svuid()
change_svgid()
In each case, the call now acts on a credential not a process, and as
such no longer requires more complicated process locking/etc. They
now assume the caller will do any necessary allocation of an
exclusive credential reference. Each is commented to document its
reference requirements.
o CANSIGIO() is simplified to require only credentials, not processes
and pcreds.
o Remove lots of (p_pcred==NULL) checks.
o Add an XXX to authorization code in nfs_lock.c, since it's
questionable, and needs to be considered carefully.
o Simplify posix4 authorization code to require only credentials, not
processes and pcreds. Note that this authorization, as well as
CANSIGIO(), needs to be updated to use the p_cansignal() and
p_cansched() centralized authorization routines, as they currently
do not take into account some desirable restrictions that are handled
by the centralized routines, as well as being inconsistent with other
similar authorization instances.
o Update libkvm to take these changes into account.
Obtained from: TrustedBSD Project
Reviewed by: green, bde, jhb, freebsd-arch, freebsd-audit
Tor created a while ago, removes the raw I/O piece (that has cache coherency
problems), and adds a buffer cache / VM freeing piece.
Essentially this patch causes O_DIRECT I/O to not be left in the cache, but
does not prevent it from going through the cache, hence the 80%. For
the last 20% we need a method by which the I/O can be issued directly to
buffer supplied by the user process and bypass the buffer cache entirely,
but still maintain cache coherency.
I also have the code working under -stable but the changes made to sys/file.h
may not be MFCable, so an MFC is not on the table yet.
Submitted by: tegge, dillon
systems were repo-copied from sys/miscfs to sys/fs.
- Renamed the following file systems and their modules:
fdesc -> fdescfs, portal -> portalfs, union -> unionfs.
- Renamed corresponding kernel options:
FDESC -> FDESCFS, PORTAL -> PORTALFS, UNION -> UNIONFS.
- Install header files for the above file systems.
- Removed bogus -I${.CURDIR}/../../sys CFLAGS from userland
Makefiles.
committed to disk before clearing them. More specifically, when
free_newdirblk is called, we know that the inode claims the new
directory block. However, if the associated pagedep is still linked
onto the directory buffer dependency chain, then some of the entries
on the pd_pendinghd list may not be committed to disk yet. In this
case, we will simply note that the inode claims the block and let
the pd_pendinghd list be processed when the pagedep is next written.
If the pagedep is no longer on the buffer dependency chain, then
all the entries on the pd_pending list are committed to disk and
we can free them in free_newdirblk. This corrects a window of
vulnerability introduced in the code added in version 1.95.
vm_mtx does not recurse and is required for most low level
vm operations.
faults can not be taken without holding Giant.
Memory subsystems can now call the base page allocators safely.
Almost all atomic ops were removed as they are covered under the
vm mutex.
Alpha and ia64 now need to catch up to i386's trap handlers.
FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).
Reviewed (partially) by: jake, jhb
whose name is within that block must ensure not only that the block
containing the file name has been written, but also that the on-disk
directory inode references that block. When a new directory block
is created, we allocate a newdirblk structure which is linked to
the associated allocdirect (on its ad_newdirblk list). When the
allocdirect has been satisfied, the newdirblk structure is moved
to the inodedep id_bufwait list of its directory to await the inode
being written. When the inode is written, the directory entries
are fully committed and can be deleted from their pagedep->id_pendinghd
and inodedep->id_pendinghd lists.
the number of references on the filesystem root vnode to be both
expected and released. Many filesystems hold an extra reference on
the filesystem root vnode, which must be accounted for when
determining if the filesystem is busy and then released if it isn't
busy. The old `skipvp' approach required individual filesystem
xxx_unmount functions to re-implement much of vflush()'s logic to
deal with the root vnode.
All 9 filesystems that hold an extra reference on the root vnode
got the logic wrong in the case of forced unmounts, so `umount -f'
would always fail if there were any extra root vnode references.
Fix this issue centrally in vflush(), now that we can.
This commit also fixes a vnode reference leak in devfs, which could
result in idle devfs filesystems that refuse to unmount.
Reviewed by: phk, bp
comes in for it, the file is really gone, so return ESTALE.
The problem arises when the last reference to an FFS file is
released because soft-updates may delay the actual freeing of the
inode for some time. Since there are no filesystem links or open
file descriptors referencing the inode, from the point of view of
the system, the file is inaccessible. However, if the filesystem
is NFS exported, then the remote client can still access the inode
via ufs_fhtovp() until the inode really goes away. To prevent this
anomoly, it is necessary to begin returning ESTALE at the same time
that the file ceases to be accessible to the local filesystem.
Obtained from: Ian Dowse <iedowse@maths.tcd.ie>
that are committed to being freed and reflect these blocks in the
counts returned by statfs (and thus also by the `df' command). This
change allows programs such as those that do news expiration to
know when to stop if they are trying to create a certain percentage
of free space. Note that this change does not solve the much harder
problem of making this to-be-freed space available to applications
that want it (thus on a nearly full filesystem, you may still
encounter out-of-space conditions even though the free space will
show up eventually). Hopefully this harder problem will be the
subject of a future enhancement.
1) Do not assume that the superblock will be of size fs->fs_bsize.
This fixes a panic when taking a snapshot on a filesystem with
a block size bigger than 8K.
2) Properly calculate the number of fragments that follow the
superblock summary information. This fixes a bug with inconsistent
snapshots.
3) When cleaning up a snapshot that is about to be removed, properly
calculate the number of blocks that need to be checked. This fixes
a bug that created partially allocated inodes.
4) When moving blocks from a snapshot that is about to be removed
to another snapshot, properly account for the reduced number of
blocks in the snapshot from which they are taken. This fixes a
bug in which the number of blocks released from a snapshot did not
match the number that it claimed to have.
other "system" header files.
Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.
Sort sys/*.h includes where possible in affected files.
OK'ed by: bde (with reservations)
Make 7 filesystems which don't really know about VOP_BMAP rely
on the default vector, rather than more or less complete local
vop_nopbmap() implementations.
by the inactive routine. Because the freeing causes the filesystem
to be modified, the close must be held up during periods when the
filesystem is suspended.
For snapshots to be consistent across crashes, they must write
blocks that they copy and claim those written blocks in their
on-disk block pointers before the old blocks that they referenced
can be allowed to be written.
Close a loophole that allowed unwritten blocks to be skipped when
doing ffs_sync with a request to wait for all I/O activity to be
completed.
to struct mount.
This makes the "struct netexport *" paramter to the vfs_export
and vfs_checkexport interface unneeded.
Consequently that all non-stacking filesystems can use
vfs_stdcheckexp().
At the same time, make it a pointer to a struct netexport
in struct mount, so that we can remove the bogus AF_MAX
and #include <net/radix.h> from <sys/mount.h>
fs_contigdirs, fs_avgfilesize and fs_avgfpdir. This could cause
panics if these fields were zeroed while a filesystem was mounted
read-only, and then remounted read-write.
Add code to ffs_reload() which copies the fs_contigdirs pointer
from the previous superblock, and reinitialises fs_avgf* if necessary.
Reviewed by: mckusick
VOP_BWRITE() was a hack which made it possible for NFS client
side to use struct buf with non-bio backing.
This patch takes a more general approach and adds a bp->b_op
vector where more methods can be added.
The success of this patch depends on bp->b_op being initialized
all relevant places for some value of "relevant" which is not
easy to determine. For now the buffers have grown a b_magic
element which will make such issues a tiny bit easier to debug.
sized blocks. To enable this option, use: `sysctl -w debug.bigcgs=1'.
Add debugging option to disable background writes of cylinder
groups. To enable this option, use: `sysctl -w debug.dobkgrdwrite=0'.
These debugging options should be tried on systems that are panicing
with corrupted cylinder group maps to see if it makes the problem
go away. The set of panics in question are:
ffs_clusteralloc: map mismatch
ffs_nodealloccg: map corrupted
ffs_nodealloccg: block not in map
ffs_alloccg: map corrupted
ffs_alloccg: block not in map
ffs_alloccgblk: cyl groups corrupted
ffs_alloccgblk: can't find blk in cyl
ffs_checkblk: partially free fragment
The following panics are less likely to be related to this problem,
but might be helped by these debugging options:
ffs_valloc: dup alloc
ffs_blkfree: freeing free block
ffs_blkfree: freeing free frag
ffs_vfree: freeing free inode
If you try these options, please report whether they helped reduce your
bitmap corruption panics to Kirk McKusick at <mckusick@mckusick.com>
and to Matt Dillon <dillon@earth.backplane.com>.
ACL_USER_OBJ and ACL_GROUP_OBJ fields, believing that modification of the
access ACL could be used by privileged processes to change file/directory
ownership. In fact, this is incorrect; ACL_*_OBJ (+ ACL_MASK and
ACL_OTHER) should have undefined ae_id fields; this commit attempts
to correct that misunderstanding.
o Modify arguments to vaccess_acl_posix1e() to accept the uid and gid
associated with the vnode, as those can no longer be extracted from
the ACL passed as an argument. Perform all comparisons against
the passed arguments. This actually has the effect of simplifying
a number of components of this call, as well as reducing the indent
level, but now seperates handling of ACL_GROUP_OBJ from ACL_GROUP.
o Modify acl_posix1e_check() to return EINVAL if the ae_id field of
any of the ACL_{USER_OBJ,GROUP_OBJ,MASK,OTHER} entries is a value
other than ACL_UNDEFINED_ID. As a temporary work-around to allow
clean upgrades, set the ae_id field to ACL_UNDEFINED_ID before
each check so that this cannot cause a failure in the short term
(this work-around will be removed when the userland libraries and
utilities are updated to take this change into account).
o Modify ufs_sync_acl_from_inode() so that it forces
ACL_{USER_OBJ,GROUP_OBJ,MASK,OTHER} ae_id fields to ACL_UNDEFINED_ID
when synchronizing the ACL from the inode.
o Modify ufs_sync_inode_from_acl to not propagate uid and gid
information to the inode from the ACL during ACL update. Also
modify the masking of permission bits that may be set from
ALLPERMS to (S_IRWXU|S_IRWXG|S_IRWXO), as ACLs currently do not
carry none-ACCESSPERMS (S_ISUID, S_ISGID, S_ISTXT).
o Modify ufs_getacl() so that when it emulates an access ACL from
the inode, it initializes the ae_id fields to ACL_UNDEFINED_ID.
o Clean up ufs_setacl() substantially since it is no longer possible
to perform chown/chgrp operations using vop_setacl(), so all the
access control for that can be eliminated.
o Modify ufs_access() so that it passes owner uid and gid information
into vaccess_acl_posix1e().
Pointed out by: jedger
Obtained from: TrustedBSD Project
It is described in ufs/ffs/fs.h as follows:
/*
* Filesystem flags.
*
* Note that the FS_NEEDSFSCK flag is set and cleared only by the
* fsck utility. It is set when background fsck finds an unexpected
* inconsistency which requires a traditional foreground fsck to be
* run. Such inconsistencies should only be found after an uncorrectable
* disk error. A foreground fsck will clear the FS_NEEDSFSCK flag when
* it has successfully cleaned up the filesystem. The kernel uses this
* flag to enforce that inconsistent filesystems be mounted read-only.
*/
#define FS_UNCLEAN 0x01 /* filesystem not clean at mount */
#define FS_DOSOFTDEP 0x02 /* filesystem using soft dependencies */
#define FS_NEEDSFSCK 0x04 /* filesystem needs sync fsck before mount */
His description of the problem and solution follow. My own tests show
speedups on typical filesystem intensive workloads of 5% to 12% which
is very impressive considering the small amount of code change involved.
------
One day I noticed that some file operations run much faster on
small file systems then on big ones. I've looked at the ffs
algorithms, thought about them, and redesigned the dirpref algorithm.
First I want to describe the results of my tests. These results are old
and I have improved the algorithm after these tests were done. Nevertheless
they show how big the perfomance speedup may be. I have done two file/directory
intensive tests on a two OpenBSD systems with old and new dirpref algorithm.
The first test is "tar -xzf ports.tar.gz", the second is "rm -rf ports".
The ports.tar.gz file is the ports collection from the OpenBSD 2.8 release.
It contains 6596 directories and 13868 files. The test systems are:
1. Celeron-450, 128Mb, two IDE drives, the system at wd0, file system for
test is at wd1. Size of test file system is 8 Gb, number of cg=991,
size of cg is 8m, block size = 8k, fragment size = 1k OpenBSD-current
from Dec 2000 with BUFCACHEPERCENT=35
2. PIII-600, 128Mb, two IBM DTLA-307045 IDE drives at i815e, the system
at wd0, file system for test is at wd1. Size of test file system is 40 Gb,
number of cg=5324, size of cg is 8m, block size = 8k, fragment size = 1k
OpenBSD-current from Dec 2000 with BUFCACHEPERCENT=50
You can get more info about the test systems and methods at:
http://www.ptci.ru/gluk/dirpref/old/dirpref.html
Test Results
tar -xzf ports.tar.gz rm -rf ports
mode old dirpref new dirpref speedup old dirprefnew dirpref speedup
First system
normal 667 472 1.41 477 331 1.44
async 285 144 1.98 130 14 9.29
sync 768 616 1.25 477 334 1.43
softdep 413 252 1.64 241 38 6.34
Second system
normal 329 81 4.06 263.5 93.5 2.81
async 302 25.7 11.75 112 2.26 49.56
sync 281 57.0 4.93 263 90.5 2.9
softdep 341 40.6 8.4 284 4.76 59.66
"old dirpref" and "new dirpref" columns give a test time in seconds.
speedup - speed increasement in times, ie. old dirpref / new dirpref.
------
Algorithm description
The old dirpref algorithm is described in comments:
/*
* Find a cylinder to place a directory.
*
* The policy implemented by this algorithm is to select from
* among those cylinder groups with above the average number of
* free inodes, the one with the smallest number of directories.
*/
A new directory is allocated in a different cylinder groups than its
parent directory resulting in a directory tree that is spreaded across
all the cylinder groups. This spreading out results in a non-optimal
access to the directories and files. When we have a small filesystem
it is not a problem but when the filesystem is big then perfomance
degradation becomes very apparent.
What I mean by a big file system ?
1. A big filesystem is a filesystem which occupy 20-30 or more percent
of total drive space, i.e. first and last cylinder are physically
located relatively far from each other.
2. It has a relatively large number of cylinder groups, for example
more cylinder groups than 50% of the buffers in the buffer cache.
The first results in long access times, while the second results in
many buffers being used by metadata operations. Such operations use
cylinder group blocks and on-disk inode blocks. The cylinder group
block (fs->fs_cblkno) contains struct cg, inode and block bit maps.
It is 2k in size for the default filesystem parameters. If new and
parent directories are located in different cylinder groups then the
system performs more input/output operations and uses more buffers.
On filesystems with many cylinder groups, lots of cache buffers are
used for metadata operations.
My solution for this problem is very simple. I allocate many directories
in one cylinder group. I also do some things, so that the new allocation
method does not cause excessive fragmentation and all directory inodes
will not be located at a location far from its file's inodes and data.
The algorithm is:
/*
* Find a cylinder group to place a directory.
*
* The policy implemented by this algorithm is to allocate a
* directory inode in the same cylinder group as its parent
* directory, but also to reserve space for its files inodes
* and data. Restrict the number of directories which may be
* allocated one after another in the same cylinder group
* without intervening allocation of files.
*
* If we allocate a first level directory then force allocation
* in another cylinder group.
*/
My early versions of dirpref give me a good results for a wide range of
file operations and different filesystem capacities except one case:
those applications that create their entire directory structure first
and only later fill this structure with files.
My solution for such and similar cases is to limit a number of
directories which may be created one after another in the same cylinder
group without intervening file creations. For this purpose, I allocate
an array of counters at mount time. This array is linked to the superblock
fs->fs_contigdirs[cg]. Each time a directory is created the counter
increases and each time a file is created the counter decreases. A 60Gb
filesystem with 8mb/cg requires 10kb of memory for the counters array.
The maxcontigdirs is a maximum number of directories which may be created
without an intervening file creation. I found in my tests that the best
performance occurs when I restrict the number of directories in one cylinder
group such that all its files may be located in the same cylinder group.
There may be some deterioration in performance if all the file inodes
are in the same cylinder group as its containing directory, but their
data partially resides in a different cylinder group. The maxcontigdirs
value is calculated to try to prevent this condition. Since there is
no way to know how many files and directories will be allocated later
I added two optimization parameters in superblock/tunefs. They are:
int32_t fs_avgfilesize; /* expected average file size */
int32_t fs_avgfpdir; /* expected # of files per directory */
These parameters have reasonable defaults but may be tweeked for special
uses of a filesystem. They are only necessary in rare cases like better
tuning a filesystem being used to store a squid cache.
I have been using this algorithm for about 3 months. I have done
a lot of testing on filesystems with different capacities, average
filesize, average number of files per directory, and so on. I think
this algorithm has no negative impact on filesystem perfomance. It
works better than the default one in all cases. The new dirpref
will greatly improve untarring/removing/coping of big directories,
decrease load on cvs servers and much more. The new dirpref doesn't
speedup a compilation process, but also doesn't slow it down.
Obtained from: Grigoriy Orlov <gluk@ptci.ru>
to not using IO_SYNC. Expose a sysctl (debug.ufs_extattr_sync) for
enabling the use of IO_SYNC.
- Use of IO_SYNC substantially degrades ACL performance when a
default ACL is set on a directory, as there are four synchronous
writes initiated to define both supporting EAs for new
sub-directories, and to set the data; two for new files. Later, this
may be optimized to two writes for sub-directories, one for new
files.
- IO_SYNC does not substantially improve consistency properties due
to the poor consistency properties of existing permissions (which
ACLs are a superset of), due to interaction with soft updates,
and due to differences in handling consistency for data and file
system meta-data.
- In macro-benchmarks, this reduces the overhead of setting default
ACLs down to the same overhead as enabling ACLs on a file system
and not using them. Enabling ACLs still introduces a small
overhead (I measure 7% on a -j 2 buildworld with pre-allocated
EA backing store, but this is not rigorous testing, nor in any way
optimized).
- The sysctl will probably change to another administration method
(or at least, a better name) in the near future, but consistency
properties of EAs are still being worked out. The toggle is defined
right now to allow easier performance analysis and exploration
of possible guarantees.
Obtained from: TrustedBSD Project
under heavy use when default ACLs were bgin inherited by new files
or directories. This is done by removing a bug in default ACL
reading, and improving error handling for this failure case:
- Move the setting of the buffer length (len) variable to above the
ACL type (ap->a_type) switch rather than having it only for
ACL_TYPE_ACCESS. Otherwise, the len variable is unitialized in
the ACL_TYPE_DEFAULT case, which generally worked right, but could
result in failure.
- Add a check for a short/long read of the ACL_TYPE_DEFAULT type from
the underlying EA, resulting in EPERM rather than passing a
potentially corrupted ACL back to the caller (resulting "cleaner"
failures if the EA is damaged: right now, the caller will almost
always panic in the presence of a corrupted EA). This code is similar
to code in the ACL_TYPE_ACCESS handling in the previous switch case.
- While I'm fixing this code, remove a redundant bzero() of the ACL
reader buffer; it need only be initialized above the acl_type
switch.
Obtained from: TrustedBSD Project
implementation is still experimental, and while fairly broadly tested,
is not yet intended for production use. Support for POSIX.1e ACLs on
UFS will not be MFC'd to RELENG_4.
This implementation works by providing implementations of VOP_[GS]ETACL()
for FFS, as well as modifying the appropriate access control and file
creation routines. In this implementation, ACLs are backed into extended
attributes; the base ACL (owner, group, other) permissions remain in the
inode for performance and compatibility reasons, so only the extended and
default ACLs are placed in extended attributes. The logic for ACL
evaluation is provided by the fs-independent kern/kern_acl.c.
o Introduce UFS_ACL, a compile-time configuration option that enables
support for ACLs on FFS (and potentially other UFS-based file systems).
o Introduce ufs_getacl(), ufs_setacl(), ufs_aclcheck(), which
respectively get, set, and check the ACLs on the passed vnode.
o Introduce ufs_sync_acl_from_inode(), ufs_sync_inode_from_acl() to
maintain access control information between inode permissions and
extended attribute data.
o Modify ufs_access() to load a file access ACL and invoke
vaccess_acl_posix1e() if ACLs are available on the file system
o Modify ufs_mkdir() and ufs_makeinode() to associate ACLs with newly
created directories and files, inheriting from the parent directory's
default ACL.
o Enable these new vnode operations and conditionally compiled code
paths if UFS_ACL is defined.
A few notes:
o This implementation is fairly widely tested, but still should be
considered experimental.
o Currently, ACLs are not exported via NFS, instead, the summarizing
file mode/etc from the inode is. This results in conservative
protection behavior, similar to the behavior of ACL-nonaware programs
acting locally.
o It is possible that underlying binary data formats associated with
this implementation may change. Consumers of the implementation
should expect to find their local configuration obsoleted in the
next few months, resulting in possible loss of ACL data during an
upgrade.
o The extended attributes interface and implementation is still
undergoing modification to address portable interface concerns, as
well as performance.
o Many applications do not yet correctly handle ACLs. In general,
due to the POSIX.1e ACL model, behavior of ACL-unaware applications
will be conservative with respects to file protection; some caution
is recommended.
o Instructions for configuring and maintaining ACLs on UFS will be
committed in the near future; in the mean time it is possible to
reference the README included in the last UFS ACL distribution
placed in the TrustedBSD web site:
http://www.TrustedBSD.org/downloads/
Substantial debugging, hardware, travel, or connectivity support for this
project was provided by: BSDi, Safeport Network Services, and NAI Labs.
Significant coding contributions were made by Chris Faulhaber. Additional
support was provided by Brian Feldman, Thomas Moestl, and Ilmar Habibulin.
Reviewed by: jedgar, keichii, mckusick, trustedbsd-discuss, freebsd-fs
Obtained from: TrustedBSD Project
which resulted in the output of warning messages at boot if
UFS_EXTATTR_AUTOSTART was enabled but ".attribute" and possible
sub-directories weren't in a mounted MFS or UFS file systems.
Pointed out by: dcs
Obtained from: TrustedBSD Project
(as is done in unmount).
Remove a snapshot inode from the superblock list when its last
name goes away rather than when its last reference goes away.
That way it will be properly reclaimed by fsck after a crash
rather than reenabled when the filesystem is mounted.
is under-tested, and that MFS appears to be in the process of being
deprecated in favor of FFS over md. Note also that UFS_EXTATTR_AUTOSTART
doesn't make much sense on MFS unless the MFSROOT is compiled in, so
manual configuration is generally required.
Obtained from: TrustedBSD Project
options UFS_EXTATTR and UFS_EXTATTR_AUTOSTART respectively. This change
reflects the fact that our EA support is implemented entirely at the
UFS layer (modulo FFS start/stop/autostart hooks for mount and unmount
events). This also better reflects the fact that [shortly] MFS will also
support EAs, as well as possibly IFS.
o Consumers of the EA support in FFS are reminded that as a result, they
must change kernel config files to reflect the new option names.
Obtained from: TrustedBSD Project
off of the file system root: "user" for user attributes, and "system"
for system attributes. When the scan occurs, attribute backing files
discovered in those directories will be started in the respective
namespaces. This re-introduces support for auto-starting of user
attributes, which was removed when the "$" prefix for system attributes
was replaced with explicit namespacing.
For users of the TrustedBSD UFS POSIX.1e ACL code, you'll need to:
mv ${FSROOT}/'$posix1e.acl_access' ${FSROOT}/system/posix1e.acl_access
mv ${FSROOT}/'$posix1e.acl_default' ${FSROOT}/system/posix1e.acl_default
For users of the TrustedBSD POSIX.1e Capability code, you'll need to:
mv ${FSROOT}/'$posix1e.cap' ${FSROOT}/system/posix1e.cap
For users of the TrustedBSD MAC code, you'll need to:
mv ${FSROOT}/'$freebsd.mac' ${FSROOT}/system/freebsd.mac
Updated versions of relevant patches will be released in the near
future.
Obtained from: TrustedBSD Project
introduce a new argument, "namespace", rather than relying on a first-
character namespace indicator. This is in line with more recent
thinking on EA interfaces on various mailing lists, including the
posix1e, Linux acl-devel, and trustedbsd-discuss forums. Two namespaces
are defined by default, EXTATTR_NAMESPACE_SYSTEM and
EXTATTR_NAMESPACE_USER, where the primary distinction lies in the
access control model: user EAs are accessible based on the normal
MAC and DAC file/directory protections, and system attributes are
limited to kernel-originated or appropriately privileged userland
requests.
o These API changes occur at several levels: the namespace argument is
introduced in the extattr_{get,set}_file() system call interfaces,
at the vnode operation level in the vop_{get,set}extattr() interfaces,
and in the UFS extended attribute implementation. Changes are also
introduced in the VFS extattrctl() interface (system call, VFS,
and UFS implementation), where the arguments are modified to include
a namespace field, as well as modified to advoid direct access to
userspace variables from below the VFS layer (in the style of recent
changes to mount by adrian@FreeBSD.org). This required some cleanup
and bug fixing regarding VFS locks and the VFS interface, as a vnode
pointer may now be optionally submitted to the VFS_EXTATTRCTL()
call. Updated documentation for the VFS interface will be committed
shortly.
o In the near future, the auto-starting feature will be updated to
search two sub-directories to the ".attribute" directory in appropriate
file systems: "user" and "system" to locate attributes intended for
those namespaces, as the single filename is no longer sufficient
to indicate what namespace the attribute is intended for. Until this
is committed, all attributes auto-started by UFS will be placed in
the EXTATTR_NAMESPACE_SYSTEM namespace.
o The default POSIX.1e attribute names for ACLs and Capabilities have
been updated to no longer include the '$' in their filename. As such,
if you're using these features, you'll need to rename the attribute
backing files to the same names without '$' symbols in front.
o Note that these changes will require changes in userland, which will
be committed shortly. These include modifications to the extended
attribute utilities, as well as to libutil for new namespace
string conversion routines. Once the matching userland changes are
committed, a buildworld is recommended to update all the necessary
include files and verify that the kernel and userland environments
are in sync. Note: If you do not use extended attributes (most people
won't), upgrading is not imperative although since the system call
API has changed, the new userland extended attribute code will no longer
compile with old include files.
o Couple of minor cleanups while I'm there: make more code compilation
conditional on FFS_EXTATTR, which should recover a bit of space on
kernels running without EA's, as well as update copyright dates.
Obtained from: TrustedBSD Project
"options FFS_EXTATTR". When extended attribute auto-starting
is enabled, FFS will scan the .attribute directory off of the
root of each file system, as it is mounted. If .attribute
exists, EA support will be started for the file system. If
there are files in the directory, FFS will attempt to start
them as attribute backing files for attributes baring the same
name. All attributes are started before access to the file
system is permitted, so this permits race-free enabling of
attributes. For attributes backing support for security
features, such as ACLs, MAC, Capabilities, this is vital, as
it prevents the file system attributes from getting out of
sync as a result of file system operations between mount-time
and the enabling of the extended attribute. The userland
extattrctl tool will still function exactly as previously.
Files must be placed directly in .attribute, which must be
directly off of the file system root: symbolic links are
not permitted. FFS_EXTATTR will continue to be able
to function without FFS_EXTATTR_AUTOSTART for sites that do not
want/require auto-starting. If you're using the UFS_ACL code
available from www.TrustedBSD.org, using FFS_EXTATTR_AUTOSTART
is recommended.
o This support is implemented by adding an invocation of
ufs_extattr_autostart() to ffs_mountfs(). In addition,
several new supporting calls are introduced in
ufs_extattr.c:
ufs_extattr_autostart(): start EAs on the specified mount
ufs_extattr_lookup(): given a directory and filename,
return the vnode for the file.
ufs_extattr_enable_with_open(): invoke ufs_extattr_enable()
after doing the equililent of vn_open()
on the passed file.
ufs_extattr_iterate_directory(): iterate over a directory,
invoking ufs_extattr_lookup() and
ufs_extattr_enable_with_open() on each
entry.
o This feature is not widely tested, and therefore may contain
bugs, caution is advised. Several changes are in the pipeline
for this feature, including breaking out of EA namespaces into
subdirectories of .attribute (this is waiting on the updated
EA API), as well as a per-filesystem flag indicating whether
or not EAs should be auto-started. This is required because
administrators may not want .attribute auto-started on all
file systems, especially if non-administrators have write access
to the root of a file system.
Obtained from: TrustedBSD Project
