our cached 'next vnode' being removed from this mountpoint. If we
find that it was recycled, we restart our traversal from the start
of the list.
Code to do that is in all local disk filesystems (and a few other
places) and looks roughly like this:
MNT_ILOCK(mp);
loop:
for (vp = TAILQ_FIRST(&mp...);
(vp = nvp) != NULL;
nvp = TAILQ_NEXT(vp,...)) {
if (vp->v_mount != mp)
goto loop;
MNT_IUNLOCK(mp);
...
MNT_ILOCK(mp);
}
MNT_IUNLOCK(mp);
The code which takes vnodes off a mountpoint looks like this:
MNT_ILOCK(vp->v_mount);
...
TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes);
...
MNT_IUNLOCK(vp->v_mount);
...
vp->v_mount = something;
(Take a moment and try to spot the locking error before you read on.)
On a SMP system, one CPU could have removed nvp from our mountlist
but not yet gotten to assign a new value to vp->v_mount while another
CPU simultaneously get to the top of the traversal loop where it
finds that (vp->v_mount != mp) is not true despite the fact that
the vnode has indeed been removed from our mountpoint.
Fix:
Introduce the macro MNT_VNODE_FOREACH() to traverse the list of
vnodes on a mountpoint while taking into account that vnodes may
be removed from the list as we go. This saves approx 65 lines of
duplicated code.
Split the insmntque() which potentially moves a vnode from one mount
point to another into delmntque() and insmntque() which does just
what the names say.
Fix delmntque() to set vp->v_mount to NULL while holding the
mountpoint lock.
because UFS uses fixed-size directory blocks. When using this code with
other file systems, such as HFS+, the value of auio.uio_resid will need
to be taken into account.
local to a function. Remove a couple of blank lines in variable
declarations.
In one case, explicitly test against NULL rather than using a pointer
as a boolean directly.
lots of errors. Blind substitution of "dev_t foo" by "struct cdev *foo"
in comments usually just created an English syntax error (e.g.,
"struct cdev *changes"), but here it did less than that since the dev_t
is a user dev_t.
fixes was applicable to HEAD, originally it was thought this
should only be done in RELENG_4. Implement IO_INVAL in the vnode
op for writing by marking the buffer as "no cache". This fix
has already been applied to RELENG_4 as Rev. 1.65.2.15 of
ufs/ufs/ufs_readwrite.c.
Reviewed by: alc, tegge
fragment to zero the valid parts of a VM_IO buffer.
RE would like this to be part of 4.10-RC3 so this will be MFC-ed immediately.
Reviewed by: alc, tegge
things which compare /etc/fstab entries to results from
getfsstat(). The real way to fix this is to make 'ufs2'
a recognized filesystem (for real, no beating around the
bush).
This should fix things like 'umount -a -t ufs' now.
Appologies for the previous breakage.
libufs, which only works for Charlie root.
This change reverts the introduction of libufs and moves the
check into the kernel. Since the f_fstypename is the same
for both ufs and ufs2, we check fs_magic for presence of
ufs2 and copy "ufs2" explicitly instead.
Submitted by: Christian S.J. Peron <maneo@bsdpro.com>
license, per letter dated July 22, 1999 and irc message from Robert
Watson saying that clause 3 can be removed from those files with an
NAI copyright that also have only a University of California
copyrights.
Approved by: core, rwatson
WARNS=6. I don't change the WARNS level in the Makefile because I
didn't tested this on other archs.
The fs.h fix was suggested by: marcel
Reviewed by: md5(1)
group block locked. If filesystem has any active snapshots, bawrite
can come back trying to allocate new snapshot data block from the same
cylinder group and cause panic due to recursive lock attempt.
PR: 64206
Reviewed by: mckusick
Tested by: pjd
were a rather overwhelming task. I soon learned that if you don't know
where you're going to store something, at least try to pile it next to
something slightly related in the hope that a pattern emerges.
Apply the same principle to the ffs/snapshot/softupdates code which have
leaked into specfs: Add yet a buf-quasi-method and call it from the
only two places I can see it can make a difference and implement the
magic in ffs_softdep.c where it belongs.
It's not pretty, but at least it's one less layer violated.
AFTER the call to vn_start_write(), not before it. Otherwise, it is
possible to unlock it multiple times if the vn_start_write() fails.
Submitted by: Juergen Hannken-Illjes <hannken@eis.cs.tu-bs.de>
In ufs_lock, check for attempts to acquire shared locks on
snapshot files and change them to be exclusive locks. This
change eliminates deadlocks and machine lockups reported in
-current since most read requests started using shared lock
requests.
Submitted by: Jun Kuriyama <kuriyama@imgsrc.co.jp>
to use the "year1-year3" format, as opposed to "year1, year2, year3".
This seems to make lawyers more happy, but also prevents the
lines from getting excessively long as the years start to add up.
Suggested by: imp
- don't unlock the vnode after vinvalbuf() only to have to relock it
almost immediately.
- don't refer to devices classified by vn_isdisk() as block devices.
operators) in and near revs.1.169-1.170 (open mode bandaid). This
(or better a proper fix) should have been done before cloning the
bandaid to many other file systems.
- rev.1.42 of ffs_readwrite.c added a special case in ffs_read() for reads
that are initially at EOF, and rev.1.62 of ufs_readwrite.c fixed
timestamp bugs in it. Removal of most of vfs_ioopt made it just and
optimization, and removal of the vm object reference calls made it less
than an optimization. It was cloned in rev.1.94 of ufs_readwrite.c as
part of cloning ffs_extwrite() although it was always less than an
optimization in ffs_extwrite().
- some comments, compound statements and vertical whitespace were vestiges
of dead code.
- struct plimit includes a mutex to protect a reference count. The plimit
structure is treated similarly to struct ucred in that is is always copy
on write, so having a reference to a structure is sufficient to read from
it without needing a further lock.
- The proc lock protects the p_limit pointer and must be held while reading
limits from a process to keep the limit structure from changing out from
under you while reading from it.
- Various global limits that are ints are not protected by a lock since
int writes are atomic on all the archs we support and thus a lock
wouldn't buy us anything.
- All accesses to individual resource limits from a process are abstracted
behind a simple lim_rlimit(), lim_max(), and lim_cur() API that return
either an rlimit, or the current or max individual limit of the specified
resource from a process.
- dosetrlimit() was renamed to kern_setrlimit() to match existing style of
other similar syscall helper functions.
- The alpha OSF/1 compat layer no longer calls getrlimit() and setrlimit()
(it didn't used the stackgap when it should have) but uses lim_rlimit()
and kern_setrlimit() instead.
- The svr4 compat no longer uses the stackgap for resource limits calls,
but uses lim_rlimit() and kern_setrlimit() instead.
- The ibcs2 compat no longer uses the stackgap for resource limits. It
also no longer uses the stackgap for accessing sysctl's for the
ibcs2_sysconf() syscall but uses kernel_sysctl() instead. As a result,
ibcs2_sysconf() no longer needs Giant.
- The p_rlimit macro no longer exists.
Submitted by: mtm (mostly, I only did a few cleanups and catchups)
Tested on: i386
Compiled on: alpha, amd64
and ffs_write(). These calls trace their origins to the dead vfs_ioopt
code, first appearing in revision 1.39 of ufs_readwrite.c.
Observed by: bde
Discussed with: tegge
Replace wrong check returned EFBIG with EOVERFLOW handling from POSIX:
36708 [EOVERFLOW] The file is a regular file, nbyte is greater than 0, the
starting position is before the end-of-file, and the starting position is
greater than or equal to the offset maximum established in the open file
description associated with fildes.
ffs_write:
Replace u_int64_t cast with uoff_t cast which is more natural for types
used.
ffs_write & ffs_read:
Remove uio_offset and uio_resid checks for negative values, the caller
supposed to do it already. Add comments about it.
Reviewed by: bde
Move diagnostic printf after vget. This might delay the debug
output some, but at least it keeps kernel from exploding if
DEBUG_VFS_LOCKS is in effect.
system super block after fsck has repaired the file system. The value of
fs_ronly was getting overwritten, which caused ffs_update() to attempt to
update inode timestamps even though the file system was still mounted
read-only.
This fixes the "giving up on N buffers" error that is triggered by running
fsck on the root file system and then rebooting without mounting the file
system read-write.
of newfs, to signify the newfs operation has not yet completed. Re-
write the superblock with the correct magic number once all of the
cylinder groups have been created to show the operation has finished.
Sponsored by: St. Bernard Software
accurate reporting of multi-terabyte filesystem sizes.
You should build and boot a new kernel BEFORE doing a `make world'
as the new kernel will know about binaries using the old statfs
structure, but an old kernel will not know about the new system
calls that support the new statfs structure. Running an old kernel
after a `make world' will cause programs such as `df' that do a
statfs system call to fail with a bad system call.
Reviewed by: Bruce Evans <bde@zeta.org.au>
Reviewed by: Tim Robbins <tjr@freebsd.org>
Reviewed by: Julian Elischer <julian@elischer.org>
Reviewed by: the hoards of <arch@freebsd.org>
Sponsored by: DARPA & NAI Labs.
Introduce two new macros MNT_ILOCK(mp)/MNT_IUNLOCK(mp) to
operate on this mutex transparently.
Eventually new mutex will be protecting more fields in
struct mount, not only vnode list.
Discussed with: jeff
