Currently mount update keeps vfs_busy(9) reference on the mount point
during MNT_UPDATE VFS_MOUNT() vfsops call. This already provides the
exclusion, but is problematic for filesystems which need to perform
namei(9) during VFS_MOUNT(MNT_UPDATE) operations, e.g. to refresh
mnt_from path, because namei(9) must not be called while the
vfs_busy(9) reference is owned.
Check for MNT_UPDATE flag before setting MNTK_UNMOUNT, and for
MNTK_UNMOUNT before entering innards of vfs_domount_update(), failing
syscalls with EBUSY if conflict is detected. Keep vfs_busy(9)
reference around VFS_MOUNT(MNT_UPDATE) calls still to not change VFS
KPI.
In the update path in ffs_mount(), drop vfs_busy() reference around
namei(), which is now safe due to unmount never executing in parallel
with VFS_MOUNT(MNT_UPDATE), and which avoids the deadlock.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Other uses of cache_purgevfs() do rely on the cache purge for correct
operations, when paths are invalidated without unmount.
Reported and tested by: jkim
Discussed with: mjg
Sponsored by: The FreeBSD Foundation
Previously free vnodes would always by directly returned to the global
LRU list. With this change up to mnt_free_list_batch vnodes are collected
first.
syncer runs always return the batch regardless of its size.
While vnodes on per-mnt lists are not counted as free, they can be
returned in case of vnode shortage.
Reviewed by: kib
Tested by: pho
any open vnodes before proceeding. Make autounmound(8) use this flag.
Without it, even an unsuccessfull unmount causes filesystem flush,
which interferes with normal operation.
Reviewed by: kib@
Approved by: re (gjb@)
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D7047
we set MNTK_UNMOUNT flag on the mp. Otherwise parallel unmount which
wins race with us could dereference the covered vnode, and we are
left with the locked freed memory.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
Approved by: re (gjb)
MFC after: 1 week
This is a bit hackish, but the flag is currently set only for ZFS
snapshots mounted under .zfs. mountcheckdirs() can change cdir/rdir
references to a covered vnode. But for the said snapshots the covered
vnode is really ephemeral and it must never be accessed (except
for a few specific cases).
To do: consider removing mountcheckdirs() entirely
MFC after: 5 days
export_args on mount update, bzero() is consistent with
vfs_oexport_conv().
Make the code structure more explicit by using switch.
Return EINVAL if export option layout (deduced from size) is unknown.
Based on the submission by: bde
Sponsored by: The FreeBSD Foundation
reason this didn't result in an unclean shutdown is that devfs ignores
MNT_FORCE flag.
Reviewed by: kib@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3467
asserts are made. Remove them, since we might dereference freed
memory. Leaked locks are asserted by the syscall return code anyway.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Nothing stops a parallel unmount to suceed before the given call to
dounmount() checks and locks the covered vnode. Prevent dounmount()
from acting on the freed (although type-stable) memory by changing the
interface to require the mount point to be referenced. dounmount()
consumes the reference on return, regardless of the sucessfull or
erronous result.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
unmount, which causes error from nmount(2) call when performing
MNT_DELEXPORT over the directory which ceased to be a mount point.
The race is legitimate and innocent, but results in the chatty mountd.
Silence it by providing an distinguished error code for the situation,
and ignoring the error in mountd loop.
Based on the patch by: Andreas Longwitz <longwitz@incore.de>
Prodded and tested by: bdrewery
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Since VFS does not/cannot stop writes, sync might run indefinitely, or
be a wrong thing to do at all. E. g. NFS ignores VFS_SYNC() for
forced unmounts, since non-responding server does not allow sync to
finish. On the other hand, filesystems can and do stop writes using
fs-specific facilities, and should already fully flush caches in
VFS_UNMOUNT() due to the race.
Adjust msdosfs tp sync in unmount for forced call, to accomodate the
new behaviour. Note that it is still racy, since writes are not
stopped.
Discussed with: avg, bjk, mckusick
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
UNIX systems, eg. MacOS X and Solaris. It uses Sun-compatible map format,
has proper kernel support, and LDAP integration.
There are still a few outstanding problems; they will be fixed shortly.
Reviewed by: allanjude@, emaste@, kib@, wblock@ (earlier versions)
Phabric: D523
MFC after: 2 weeks
Relnotes: yes
Sponsored by: The FreeBSD Foundation
It could be claimed that two things were reasonable protected by
Giant. One is vfsconf list links, which is converted to the new
dedicated sx vfsconf_sx. Another is vfsconf.vfc_refcount, which is
now updated with atomics.
Note that vfc_refcount still has the same races now as it has under
the Giant, the unload of filesystem modules can happen while the
module is still in use.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
not strlen as they are *not* strings.
Discovered by GSOC student, Mike Ma <mikemandarine@gmail.com> during his
fuse.glusterfs port to FreeBSD.
Final patch from mckusick@
Submitted by: mckusick@
Approved by: re (hrs)
MFC after: 2 weeks
waiting for an RPC reply from the server while holding the mount
point busy (mnt_lockref incremented). This happens because dounmount()
msleep()s waiting for mnt_lockref to become 0, before calling
VFS_UNMOUNT(). This patch adds a new VFS operation called VFS_PURGE(),
which the NFS client implements as purging RPCs in progress. Making
this call before checking mnt_lockref fixes the problem, by ensuring
that the VOP_xxx() calls will fail and unbusy the mount point.
Reported by: sbruno
Reviewed by: kib
MFC after: 2 weeks
about mount and unmount events. This is used by Juniper to implement a more
optimal implementation of NetBSD's veriexec.
This change differs from r253224 in the following way:
o The vfs_mounted handler is called before mountcheckdirs() and with
newdp locked. vp is unlocked.
o The event handlers are declared in <sys/eventhandler.h> and not in
<sys/mount.h>. The <sys/mount.h> header is used in user land code
that pretends to be kernel code and as such creates a very convoluted
environment. It's hard to untangle.
Submitted by: stevek@juniper.net
Discussed with: pjd@
Obtained from: Juniper Networks, Inc.
about mount and unmount events. This is used by Juniper to implement a more
optimal implementation of NetBSD's veriexec.
Submitted by: stevek@juniper.net
Obtained from: Juniper Networks, Inc
becoming too low, the softdep flush thread processes the workitems,
which frees the space in journal, and then unsuspends the fs. The
softdep_flush() and other workitem processing functions busy the
filesystem before iterating over the worklist, to prevent the parallel
unmount from freeing the mount data. The vfs_busy() is called with
MBF_NOWAIT flag.
Now, if the unmount is already started and the filesystem is suspended
due to low journal space, the journal is never flushed and filesystem
is never unsuspended, because vfs_busy(MBF_NOWAIT) call cannot succeed
for the unmounting fs, and softdep_flush() does not process the
workitems. Unmount needs to write metadata, where it hangs in the
"suspfs" state.
Move the vn_start_write() call in the dounmount() before setting the
MNTK_UNMOUNT flag. This practically ensures that softdep_flush()
processed the pending journal writes by making dounmount() wait for
the lift of the suspension.
Sponsored by: The FreeBSD Foundation
Reported and tested by: pho
MFC after: 2 weeks
When kern_yield() was introduced with the possibility to specify
a new priority, the behaviour changed by not lowering priority at all
in the consumers, making the yielding mechanism highly ineffective for
high priority kthreads like bufdaemon, syncer, vlrudaemon, etc.
There are no evidences that consumers could bear with such change in
semantic and this situation could finally lead to bugs similar to the
ones fixed in r244240.
Re-specify userland pri for kthreads involved.
Tested by: pho
Reviewed by: kib, mdf
MFC after: 1 week
Remove redundant call to AUDIT_ARG_UPATH1().
Path will be remembered by the following NDINIT(AUDITVNODE1) call.
Sponsored by: FreeBSD Foundation (auditdistd)
MFC after: 2 weeks
In particular, do not lock Giant conditionally when calling into the
filesystem module, remove the VFS_LOCK_GIANT() and related
macros. Stop handling buffers belonging to non-mpsafe filesystems.
The VFS_VERSION is bumped to indicate the interface change which does
not result in the interface signatures changes.
Conducted and reviewed by: attilio
Tested by: pho
about vnode reclamation. Typical use is for the bypass mounts like
nullfs to get a notification about lower vnode going away.
Now, vgone() calls new VFS op vfs_reclaim_lowervp() with an argument
lowervp which is reclaimed. It is possible to register several
reclamation event listeners, to correctly handle the case of several
nullfs mounts over the same directory.
For the filesystem not having nullfs mounts over it, the overhead
added is a single mount interlock lock/unlock in the vnode reclamation
path.
In collaboration with: pho
MFC after: 3 weeks
a mount point. Active vnodes are those with a non-zero use or hold
count, e.g., those vnodes that are not on the free list. Note that
this list is in addition to the list of all the vnodes associated
with a mount point.
To avoid adding another set of linkage pointers to the vnode
structure, the active list uses the existing linkage pointers
used by the free list (previously named v_freelist, now renamed
v_actfreelist).
This update adds the MNT_VNODE_FOREACH_ACTIVE interface that loops
over just the active vnodes associated with a mount point (typically
less than 1% of the vnodes associated with the mount point).
Reviewed by: kib
Tested by: Peter Holm
MFC after: 2 weeks
The primary changes are that the user of the interface no longer
needs to manage the mount-mutex locking and that the vnode that
is returned has its mutex locked (thus avoiding the need to check
to see if its is DOOMED or other possible end of life senarios).
To minimize compatibility issues for third-party developers, the
old MNT_VNODE_FOREACH interface will remain available so that this
change can be MFC'ed to 9. Following the MFC to 9, MNT_VNODE_FOREACH
will be removed in head.
The reason for this update is to prepare for the addition of the
MNT_VNODE_FOREACH_ACTIVE interface that will loop over just the
active vnodes associated with a mount point (typically less than
1% of the vnodes associated with the mount point).
Reviewed by: kib
Tested by: Peter Holm
MFC after: 2 weeks
This function updates path string to vnode's full global path and checks
the size of the new path string against the pathlen argument.
In vfs_domount(), sys_unmount() and kern_jail_set() this new function
is used to update the supplied path argument to the respective global path.
Unbreaks jailed zfs(8) with enforce_statfs set to 1.
Reviewed by: kib
MFC after: 1 month
all the architectures.
The option allows to mount non-MPSAFE filesystem. Without it, the
kernel will refuse to mount a non-MPSAFE filesytem.
This patch is part of the effort of killing non-MPSAFE filesystems
from the tree.
No MFC is expected for this patch.
Tested by: gianni
Reviewed by: kib
so that if no vnodes in the filesystem are actively in use the unmount
will succeed rather than failing with EBUSY.
Reported by: Garrett Cooper
Reviewed by: Attilio Rao and Kostik Belousov
Tested by: Garrett Cooper
PR: kern/161016
MFC after: 3 weeks
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.
Reviewed by: rwatson
Approved by: re (bz)
doesn't operate on locked vnode. This could cause a panic.
Fix by unlocking vnode, re-locking afterwards and verifying that it wasn't
renamed or deleted. To improve readability and reduce code size, move code
to a new static function vfs_verify_global_path().
In addition, fix missing giant unlock in unmount().
Reported by: David Wolfskill <david@catwhisker.org>
Reviewed by: kib
Approved by: re (bz)
MFC after: 2 weeks
using vn_fullpath_global(). This fixes f_mntonname if mounting
inside chroot, jail or with relative path as argument.
For unmount in jail, use vn_fullpath_global() to discover
global path from supplied path argument. This fixes unmount in jail.
Reviewed by: pjd, kib
Approved by: re (kib)
MFC after: 2 weeks
32 bits to 64 bits and eliminates the unused mnt_xflag field. The
existing mnt_flag field is completely out of bits, so this update
gives us room to expand. Note that the f_flags field in the statfs
structure is already 64 bits, so the expanded mnt_flag field can
be exported without having to make any changes in the statfs structure.
Approved by: re (bz)
