The symptom was that sometimes file systems would occasionally not appear
in output from 'df' or 'mount' if the system was busy. Resolution:
- Make mount locks work somewhat like vm_map locks.
- vfs_trybusy() now only fails if the mount is gone, or if someone is
unmounting the file system. Simple contention on mnt_lock doesn't
cause it to fail.
- vfs_busy() will wait even if the file system is being unmounted.
- Do reference counting for 'struct mount'. Each vnode associated with a
mount takes a reference, and in turn the mount takes a reference to the
vfsops.
- Now that mounts are reference counted, replace the overcomplicated mount
locking inherited from 4.4BSD with a recursable rwlock.
Introduce a per-FS rename lock and new vfsops to manipulate it.
Get this lock while renaming. Also add another relookup() in do_sys_rename,
which is a hack to kludge around some of the worst deficiencies of
ufs_rename.
reviewed-by: pooka (and an earlier rev by ad)
posted on tech-kern with no objections.
shutdown). There are still problems with device access and a PR will be
filed.
- Kill checkalias(). Allow multiple vnodes to reference a single device.
- Don't play dangerous tricks with block vnodes to ensure that only one
vnode can describe a block device. Instead, prohibit concurrent opens of
block devices. As a bonus remove the unreliable code that prevents
multiple file system mounts on the same device. It's no longer needed.
- Track opens by vnode and by device. Issue cdev_close() when the last open
goes away, instead of abusing vnode::v_usecount to tell if the device is
open.
The general trend is to remove it from all kernel interfaces and
this is a start. In case the calling lwp is desired, curlwp should
be used.
quick consensus on tech-kern
knew what it was supposed to be used for and wrstuden gave a go-ahead
* while rototilling, convert file systems which went easily to
use VFS_PROTOS() instead of manually prototyping the methods
need to understand the locking around that field. Instead of setting
B_ERROR, set b_error instead. b_error is 'owned' by whoever completes
the I/O request.
fs code is a kernel buffer, pass though the length of the buffer as well.
Since the length of the userspace buffer isn'it (yet) passed through the mount
system call, add a field to the vfsops structure containing the default length.
Split sys_mount() for calls from compat code.
Ride one of the recent kernel version changes - old fs LKMs will load, but
sys_mount() will reject any attempt to use them.
an init method. So get rid of it and #ifdef _LKM and just always
init in the init method. Give malloc types the same treatment.
Makes file systems nicer to work with in linksetless environments
and fixes a few LKM discrepancies.
the "smooth" syncer, as if vfs.sync.*delay = 0, but only for LFS. The
default is "on", i.e., ignore lazy sync.
Reduce the amount of polling/busy-waiting done by lfs_putpages(). To
accomplish this, copied genfs_putpages() and modified it to indicate which
page it was that caused it to return with EDEADLK. fsync()/fdatasync()
should no longer ever fail with EAGAIN, and should not consume huge
quantities of cpu.
Also, try to make dirops less likely to be written as the result of a
VOP_PUTPAGES(), while ensuring that they are written regularly.
The suspension helpers are now put into file system specific operations.
This means every file system not supporting these helpers cannot be suspended
and therefore snapshots are no longer possible.
Implemented for file systems of type ffs.
The new API is enabled on a kernel option NEWVNGATE. This option is
not enabled by default in any kernel config.
Presented and discussed on tech-kern with much input from
Bill Studenmund <wrstuden@netbsd.org> and YAMAMOTO Takashi <yamt@netbsd.org>.
Welcome to 4.99.9 (new vfs op vfs_suspendctl).
LFCNWRAPSTOP and LFCNWRAPGO.
Be less verbose about the various looping checks: use log() rather than
printf(), and only log anything if we are really looping ("count = 2" is
not an error condition).
Allow dirops sleeping on available space to be interruptible.
* Mark being-deleted files in the Ifile so we can finish deleting them
at fs mount time.
* Flag the Ifile with "cleaner must clean" when writers are waiting for
the cleaner, rather than relying solely on the cleaner's estimation of
whether it should clean or not.
* Note partial segments written by a user agent (in particular,
fsck_lfs) so that repeated rolls forward don't interfere with one
another.
* Add a new fcntl, LFCNPASS, that allows the log to wrap exactly once,
for better testing of the validity of checkpoints.
* Keep track of the on-disk nlink count when cleaning, so that we don't
partially complete directory operations while cleaning.
* Ensure that every single Ifile inode write represents a consistent
view of the filesystem. In particular, the accounting for the segment
we are writing the inode into must be correct, and the accounting for
the segment that inode used to reside in must be correct. Rather than
just rewriting the inode if we wrote it wrong, rewrite the necessary
ifile blocks before writing the inode so we never write it wrong.
* Don't unmark any VDIROP vnodes if we haven't written them to disk,
avoiding yet another problem with the "wait for the cleaner" error
return from lfs_putpages().
Also, move the last callback to an aiodone call, so we no longer do any
memory management from interrupt context.
While touching all vptofh/fhtovp functions, get rid of VFS_MAXFIDSIZ,
version the getfh(2) syscall and explicitly pass the size available in
the filehandle from userland.
Discussed on tech-kern, with lots of help from yamt (thanks!).
many inodes are cleaned at once. Make sure that we write all the pages
on vnodes that are being flushed, even if we don't think there's room;
drain v_numoutput before lfs_vflush() completes.
Also, don't allow a vnode that is in the process of being cleaned to be
chosen by getnewvnode(); this avoids a segment accounting panic in the case
that a large number of inodes are fed to lfs_markv() all at once.
