In certain emergency cases such as media failure or removal, UFS will
initiate a forced unmount in order to prevent dirty buffers from
accumulating against the no-longer-usable filesystem. The presence
of a stacked filesystem such as nullfs or unionfs above the UFS mount
will prevent this forced unmount from succeeding.
This change addreses the situation by allowing stacked filesystems to
be recursively unmounted on a taskqueue thread when the MNT_RECURSE
flag is specified to dounmount(). This call will block until all upper
mounts have been removed unless the caller specifies the MNT_DEFERRED
flag to indicate the base filesystem should also be unmounted from the
taskqueue.
To achieve this, the recently-added vfs_pin_from_vp()/vfs_unpin() KPIs
have been combined with the existing 'mnt_uppers' list used by nullfs
and renamed to vfs_register_upper_from_vp()/vfs_unregister_upper().
The format of the mnt_uppers list has also been changed to accommodate
filesystems such as unionfs in which a given mount may be stacked atop
more than one lower mount. Additionally, management of lower FS
reclaim/unlink notifications has been split into a separate list
managed by a separate set of KPIs, as registration of an upper FS no
longer implies interest in these notifications.
Reviewed by: kib, mckusick
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D31016
This is aimed at preventing stacked filesystems like nullfs and unionfs
from "losing" their lower mounts due to forced unmount. Otherwise,
VFS operations that are passed through to the lower filesystem(s) may
crash or otherwise cause unpredictable behavior.
Introduce two new functions: vfs_pin_from_vp() and vfs_unpin().
which are intended to be called on the lower mount(s) when the stacked
filesystem is mounted and unmounted, respectively.
Much as registration in the mnt_uppers list previously did, pinning
will prevent even forced unmount of the lower FS and will allow the
stacked FS to freely operate on the lower mount either by direct
use of the struct mount* or indirect use through a properly-referenced
vnode's v_mount field.
vfs_pin_from_vp() is modeled after vfs_ref_from_vp() in that it uses
the mount interlock coupled with re-checking vp->v_mount to ensure
that it will fail in the face of a pending unmount request, even if
the concurrent unmount fully completes.
Adopt these new functions in both nullfs and unionfs.
Reviewed By: kib, markj
Differential Revision: https://reviews.freebsd.org/D30401
Instead of requiring all implementations of vfs_quotactl to unbusy
the mount for Q_QUOTAON and Q_QUOTAOFF, add an "mp_busy" in/out param
to VFS_QUOTACTL(9). The implementation may then indicate to the caller
whether it needed to unbusy the mount.
Also, add stbool.h to libprocstat modules which #define _KERNEL
before including sys/mount.h. Otherwise they'll pull in sys/types.h
before defining _KERNEL and therefore won't have the bool definition
they need for mp_busy.
Reviewed By: kib, markj
Differential Revision: https://reviews.freebsd.org/D30556
Parts of libprocstat like to pretend they're kernel components for the
sake of including mount.h, and including sys/types.h in the _KERNEL
case doesn't fix the build for some reason. Revert both the
VFS_QUOTACTL() change and the follow-up "fix" for now.
Instead of requiring all implementations of vfs_quotactl to unbusy
the mount for Q_QUOTAON and Q_QUOTAOFF, add an "mp_busy" in/out param
to VFS_QUOTACTL(9). The implementation may then indicate to the caller
whether it needed to unbusy the mount.
Reviewed By: kib, markj
Differential Revision: https://reviews.freebsd.org/D30218
instead of mount_nullfs(8).
Obviously you'd need to force mount(8) to not call
mount_nullfs(8) to make use of it.
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D26934
Nullfs needs to know the root vnode of the lower fs during the
operation. Currently it caches the upper vnode of it, which is also
the root of the nullfs mount. On unmount, nullfs calls vflush() with
rootrefs == 1, and aborts non-forced unmount if there are any more
vnodes instantiated during vflush(). This means that the reference to
the root vnode after failed non-forced unmount could be lost and
nullm_rootvp points to the freed memory.
Fix it by storing the reference for lower vnode instead, which is kept
intact during vflush(). nullfs_root() now instantiates the upper
vnode of lower root. Care about VV_ROOT flag in null_nodeget().
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D21427
The current vnode layout is not smp-friendly by having frequently read data
avoidably sharing cachelines with very frequently modified fields. In
particular v_iflag inspected for VI_DOOMED can be found in the same line with
v_usecount. Instead make it available in the same cacheline as the v_op, v_data
and v_type which all get read all the time.
v_type is avoidably 4 bytes while the necessary data will easily fit in 1.
Shrinking it frees up 3 bytes, 2 of which get used here to introduce a new
flag field with a new value: VIRF_DOOMED.
Reviewed by: kib, jeff
Differential Revision: https://reviews.freebsd.org/D22715
If vflush() did not completely flushed the mount vnodes queue, either
retry for forced unmounts, or give up for non-forced. This situation
can occur when new vnodes are instantiated while vflush() worked.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
by doing most of the work in a new function prison_add_vfs in kern_jail.c
Now a jail-enabled filesystem need only mark itself with VFCF_JAIL, and
the rest is taken care of. This includes adding a jail parameter like
allow.mount.foofs, and a sysctl like security.jail.mount_foofs_allowed.
Both of these used to be a static list of known filesystems, with
predefined permission bits.
Reviewed by: kib
Differential Revision: D14681
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
Right now size of the structure is 472 bytes on amd64, which is
already large and stack allocations are indesirable. With the ino64
work, MNAMELEN is increased to 1024, which will make it impossible to have
struct statfs on the stack.
Extracted from: ino64 work by gleb
Discussed with: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
the vnode is inactivated. This contradicts with the nullfs caching
which keeps upper vnode around, as consequence keeping the use
reference to lower vnode.
Add a filesystem flag to request nullfs to not cache when mounted over
that filesystem, and set the flag for nfs v4 mounts.
Reported by: asomers
Reviewed by: rmacklem
Tested by: asomers, rmacklem
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
filesystem to the nullfs mount.
MNTK_NO_IOPF must be present on the nullfs struct mount so that struct
file fo_read and fo_write fops operate in the mode requested by the
lower mount.
MNTK_UNMAPPED_BUFS allows VOP_GETPAGES() to use unmapped buffers. It
does not matter for VOP_GETPAGES() calls from vm_fault() since handle
of the vm_object always points to the lower vnode. But it may be
useful for other situations where VOP_GETPAGES() is used.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
This obviates the need for a MNTK_SUSPENDABLE flag, since passthrough
filesystems like nullfs and unionfs no longer need to inherit this
information from their lower layer(s). This change also restores the
pre-r273336 behaviour of using the presence of a susp_clean VFS method to
request suspension support.
Reviewed by: kib, mjg
Differential Revision: https://reviews.freebsd.org/D2937
use VOP_FSYNC() to perform the NFS server's Commit operation.
This patch adds a mnt_kern_flag called MNTK_USES_BCACHE which
is set by file systems that use the buffer cache. If this flag
is not set, the NFS server always does a VOP_FSYNC().
This should be ok for old file system modules that do not set
MNTK_USES_BCACHE, since calling VOP_FSYNC() is correct, although
it might not be optimal for file systems that use the buffer cache.
Reviewed by: kib
MFC after: 2 weeks
two.
nullfs and unionfs need to request suspension if underlying filesystem(s)
use it. Utilize mnt_kern_flag for this purpose.
This is a fixup for 273271.
No strong objections from: kib
Pointy hat to: mjg
MFC after: 2 weeks
for the case when the nullfs vnode is not reclaimed. Otherwise, later
reclamation would not unlock the lower vnode.
Reported by: antoine
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
null_hashget() obtains the reference on the nullfs vnode, which must
be dropped.
- Fix a wart which existed from the introduction of the nullfs
caching, do not unlock lower vnode in the nullfs_reclaim_lowervp().
It should be innocent, but now it is also formally safe. Inform the
nullfs_reclaim() about this using the NULLV_NOUNLOCK flag set on
nullfs inode.
- Add a callback to the upper filesystems for the lower vnode
unlinking. When inactivating a nullfs vnode, check if the lower
vnode was unlinked, indicated by nullfs flag NULLV_DROP or VV_NOSYNC
on the lower vnode, and reclaim upper vnode if so. This allows
nullfs to purge cached vnodes for the unlinked lower vnode, avoiding
excessive caching.
Reported by: G??ran L??wkrantz <goran.lowkrantz@ismobile.com>
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Include some flags of the nullfs mount itself:
MNT_RDONLY, MNT_NOEXEC, MNT_NOSUID, MNT_UNION, MNT_NOSYMFOLLOW.
This allows userland code calling statfs() or fstatfs() to see these flags.
In particular, this allows opendir() to detect that a -t nullfs -o union
mount needs deduplication (otherwise at least . and .. are returned twice)
and allows rtld to detect a -t nullfs -o noexec mount as noexec.
Turn off the MNT_ROOTFS flag from the underlying filesystem because the
nullfs mount is definitely not the root filesystem.
Reviewed by: kib
MFC after: 1 week
in r245004. Although the report was for noatime option which is
non-functional for the nullfs, other standard options like nosuid or
noexec are useful with it.
Reported by: Dewayne Geraghty <dewayne.geraghty@heuristicsystems.com.au>
MFC after: 3 days
the free nullfs vnodes, switching nullfs behaviour to pre-r240285.
The option is mostly intended as the last-resort when higher pressure
on the vnode cache due to doubling of the vnode counts is not
desirable.
Note that disabling the cache costs more than 2x wall time in the
metadata-hungry scenarious. The default is "cache".
Tested and benchmarked by: pho (previous version)
MFC after: 2 weeks
it. There are two problems which shall be addressed for shared
lookups use to have measurable effect on nullfs scalability:
1. When vfs_lookup() calls VOP_LOOKUP() for nullfs, which passes lookup
operation to lower fs, resulting vnode is often only shared-locked. Then
null_nodeget() cannot instantiate covering vnode for lower vnode, since
insmntque1() and null_hashins() require exclusive lock on the lower.
Change the assert that lower vnode is exclusively locked to only
require any lock. If null hash failed to find pre-existing nullfs
vnode for lower vnode and the vnode is shared-locked, the lower vnode
lock is upgraded.
2. Nullfs reclaims its vnodes on deactivation. This is due to nullfs
inability to detect reclamation of the lower vnode. Reclamation of a
nullfs vnode at deactivation time prevents a reference to the lower
vnode to become stale.
Change nullfs VOP_INACTIVE to not reclaim the vnode, instead use the
VFS_RECLAIM_LOWERVP to get notification and reclaim upper vnode
together with the reclamation of the lower vnode.
Note that nullfs reclamation procedure calls vput() on the lowervp
vnode, temporary unlocking the vnode being reclaimed. This seems to be
fine for MPSAFE filesystems, but not-MPSAFE code often put partially
initialized vnode on some globally visible list, and later can decide
that half-constructed vnode is not needed. If nullfs mount is created
above such filesystem, then other threads might catch such not
properly initialized vnode. Instead of trying to overcome this case,
e.g. by recursing the lower vnode lock in null_reclaim_lowervp(), I
decided to rely on nearby removal of the support for non-MPSAFE
filesystems.
In collaboration with: pho
MFC after: 3 weeks
a new jail parameter node with the following parameters:
allow.mount.devfs:
allow mounting the devfs filesystem inside a jail
allow.mount.nullfs:
allow mounting the nullfs filesystem inside a jail
Both parameters are disabled by default (equals the behavior before
devfs and nullfs in jails). Administrators have to explicitly allow
mounting devfs and nullfs for each jail. The value "-1" of the
devfs_ruleset parameter is removed in favor of the new allow setting.
Reviewed by: jamie
Suggested by: pjd
MFC after: 2 weeks
Several callers of null_nodeget() did the cleanup itself, but several
missed it, most prominent being null_bypass(). Remove the cleanup from
the callers, now null_nodeget() handles lowervp free itself.
Reported and tested by: pho
MFC after: 1 week
failure (the getnewvnode cannot return an error). In this case, the
null_insmntque_dtr() already unlocked the reclaimed vnode, so VOP_UNLOCK()
in the nullfs_mount() after null_nodeget() failure is wrong.
Tested by: pho
MFC after: 1 week
method, so that callers can indicate the minimum vnode
locking requirement. This will allow some file systems to choose
to return a LK_SHARED locked vnode when LK_SHARED is specified
for the flags argument. This patch only adds the flag. It
does not change any file system to use it and all callers
specify LK_EXCLUSIVE, so file system semantics are not changed.
Reviewed by: kib
the VFS. Now all the VFS_* functions and relating parts don't want the
context as long as it always refers to curthread.
In some points, in particular when dealing with VOPs and functions living
in the same namespace (eg. vflush) which still need to be converted,
pass curthread explicitly in order to retain the old behaviour.
Such loose ends will be fixed ASAP.
While here fix a bug: now, UFS_EXTATTR can be compiled alone without the
UFS_EXTATTR_AUTOSTART option.
VFS KPI is heavilly changed by this commit so thirdy parts modules needs
to be recompiled. Bump __FreeBSD_version in order to signal such
situation.
always curthread.
As KPI gets broken by this patch, manpages and __FreeBSD_version will be
updated by further commits.
Tested by: Andrea Barberio <insomniac at slackware dot it>
VOP_ISLOCKED(arg, curthread). Now, VOP_ISLOCKED() and lockstatus() should
only acquire curthread as argument; this will lead in axing the additional
argument from both functions, making the code cleaner.
Reviewed by: jeff, kib
conjuction with 'thread' argument passing which is always curthread.
Remove the unuseful extra-argument and pass explicitly curthread to lower
layer functions, when necessary.
KPI results broken by this change, which should affect several ports, so
version bumping and manpage update will be further committed.
Tested by: kris, pho, Diego Sardina <siarodx at gmail dot com>
Remove this argument and pass curthread directly to underlying
VOP_LOCK1() VFS method. This modify makes the code cleaner and in
particular remove an annoying dependence helping next lockmgr() cleanup.
KPI results, obviously, changed.
Manpage and FreeBSD_version will be updated through further commits.
As a side note, would be valuable to say that next commits will address
a similar cleanup about VFS methods, in particular vop_lock1 and
vop_unlock.
Tested by: Diego Sardina <siarodx at gmail dot com>,
Andrea Di Pasquale <whyx dot it at gmail dot com>
