Commit Graph

384 Commits

Author SHA1 Message Date
Konstantin Belousov
714b7df502 Provide simple mutual exclusion between mount point update and unmount.
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
2016-11-13 21:49:51 +00:00
Konstantin Belousov
9eb8f495b8 Move common cleanup code into helper.
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2016-11-13 21:39:55 +00:00
Mateusz Guzik
45571f8886 vfs: assert empty tmp free list on unmount 2016-10-08 13:38:05 +00:00
Konstantin Belousov
f71d08566c Limit scope of the optimization in r306608 to dounmount() caller only.
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
2016-10-07 11:38:28 +00:00
Mateusz Guzik
5bb81f9b2d vfs: batch free vnodes in per-mnt lists
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
2016-09-30 17:27:17 +00:00
Edward Tomasz Napierala
e313b4dd95 Fix bug introduced with r302388, which could cause processes accessing
automounted shares to hang with "vfs_busy" wchan.

(As a workaround one can run 'automount -u' from cron.)

Reviewed by:	kib@
MFC after:	1 month
2016-09-21 05:44:13 +00:00
Ed Maste
69a2875821 Renumber license clauses in sys/kern to avoid skipping #3 2016-09-15 13:16:20 +00:00
Edward Tomasz Napierala
411455a8fb Replace all remaining calls to vprint(9) with vn_printf(9), and remove
the old macro.

MFC after:	1 month
2016-08-10 16:12:31 +00:00
Edward Tomasz Napierala
debc480e03 Add new unmount(2) flag, MNT_NONBUSY, to check whether there are
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
2016-07-07 09:03:57 +00:00
Konstantin Belousov
9fdbfd3b6c Do not assume that we own the use reference on the covered vnode until
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
2016-06-15 15:56:03 +00:00
Andriy Gapon
8614f45b2d dounmount: do not call mountcheckdirs() for mounts with MNT_IGNORE
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
2016-05-16 07:23:24 +00:00
Konstantin Belousov
76c404fce5 Do not copy by field when converting struct oexport_args to struct
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
2016-02-04 16:32:21 +00:00
Edward Tomasz Napierala
c9ba65040f Make vfs_unmountall() unmount /dev after /, not before. The only
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
2015-08-24 13:18:13 +00:00
Konstantin Belousov
1965f86c72 Vnode is not referenced by the vfs_domount() at the point where
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
2015-07-02 14:31:47 +00:00
Konstantin Belousov
780dca1b1e Right now, dounmount() is called with unreferenced mount point.
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
2015-05-27 09:22:50 +00:00
Konstantin Belousov
5d6f5b24ca Mountd iterating over the mount points may race with the parallel
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
2015-02-10 18:00:32 +00:00
Konstantin Belousov
b2344ab5ff Do not call VFS_SYNC() before VFS_UNMOUNT() for forced unmount.
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
2014-12-09 10:00:47 +00:00
Edward Tomasz Napierala
3914ddf8a7 Bring in the new automounter, similar to what's provided in most other
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
2014-08-17 09:44:42 +00:00
Konstantin Belousov
168f4ee0a8 Remove Giant acquisition from the mount and unmount pathes.
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
2014-08-03 03:27:54 +00:00
Bryan Drewery
97c0df733f Use proper MFSNAMELEN for fs type.
MFC after:	2 weeks
Reviewed by:	rodrigc
Also spotted by:ambrisko
2014-04-12 21:39:17 +00:00
Sean Bruno
d3baefa809 Change len checks for fstypelen and fspathlen to be against absolute len
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
2013-10-03 22:52:03 +00:00
Rick Macklem
8fe6bddff7 Forced dismounts of NFS mounts can fail when thread(s) are stuck
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
2013-09-01 23:02:59 +00:00
Marcel Moolenaar
8939c0693c Add vfs_mounted and vfs_unmounted events so that components can be informed
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.
2013-07-10 15:35:25 +00:00
Marcel Moolenaar
4612275fdb Revert r251590. It unexpectedly broke the build and there were some
questions on locking. As part of commit-bit grooming, I'd like Steve
to handle this, but can't leave things broken in the mean time.
2013-06-10 15:22:27 +00:00
Marcel Moolenaar
8c7ca16f63 Add vfs_mounted and vfs_unmounted events so that components can be informed
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
2013-06-09 23:51:26 +00:00
Gabor Kovesdan
ab3f6b347e - Correct mispellings of the word occurrence
Submitted by:	Christoph Mallon <christoph.mallon@gmx.de> (via private mail)
2013-04-17 11:40:10 +00:00
Konstantin Belousov
8d6884ce9c When the journaled FFS volume is suspended due to the journal space
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
2013-03-20 21:07:49 +00:00
David Xu
eea8d86d4d Revert revision 244760 because strncpy pads trailing space with zero,
this prevents kernel data from being leaked.

Noticed by: Joerg Sonnenberger &lt; joerg at britannica dot bec dot de &gt;
2013-01-04 11:11:12 +00:00
Konstantin Belousov
d1c5e3f8b0 Remove the deprecated MNT_VNODE_FOREACH interface. Use the
MNT_VNODE_FOREACH_ALL instead.
2013-01-03 19:02:52 +00:00
David Xu
9d4bf0db7c Use strlcpy to NULL-terminate error message even if user provided a short
buffer.
2012-12-28 02:43:33 +00:00
Attilio Rao
b1308d72c2 Fixup r218424: uio_yield() was scaling directly to userland priority.
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
2012-12-21 13:14:12 +00:00
Konstantin Belousov
796fa4fb86 Fix typo.
MFC after:	3 days
2012-12-09 20:26:51 +00:00
Pawel Jakub Dawidek
e1216d1335 IFp4 @208450:
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
2012-11-30 22:49:28 +00:00
Konstantin Belousov
5050aa86cf Remove the support for using non-mpsafe filesystem modules.
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
2012-10-22 17:50:54 +00:00
Konstantin Belousov
bcd5bb8e57 Add a facility for vgone() to inform the set of subscribed mounts
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
2012-09-09 19:17:15 +00:00
Kirk McKusick
f257ebbb2e This change creates a new list of active vnodes associated with
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
2012-04-20 06:50:44 +00:00
Kirk McKusick
71469bb38f Replace the MNT_VNODE_FOREACH interface with MNT_VNODE_FOREACH_ALL.
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
2012-04-17 16:28:22 +00:00
Gleb Kurtsou
0ff93c48da Add vfs_getopt_size. Support human readable file system options in tmpfs.
Increase maximum tmpfs file system size to 4GB*PAGE_SIZE on 32 bit archs.

Discussed with:	delphij
MFC after:	2 weeks
2012-04-07 15:27:34 +00:00
Konstantin Belousov
38ddb5725b Decomission mnt_noasync. Introduce MNTK_NOASYNC mnt_kern_flag which
allows a filesystem to request VFS to not allow MNTK_ASYNC.

MFC after:	1 week
2012-03-09 00:12:05 +00:00
Martin Matuska
a91d2201f9 Analogous to r230407 a separate path buffer in vfs_mount.c is required
for r230129. Fixes a out of bounds write to fspath.

MFC after:	10 days
2012-02-05 10:59:50 +00:00
Kirk McKusick
cc672d3599 Make sure all intermediate variables holding mount flags (mnt_flag)
and that all internal kernel calls passing mount flags are declared
as uint64_t so that flags in the top 32-bits are not lost.

MFC after: 2 weeks
2012-01-17 01:08:01 +00:00
Martin Matuska
f6e633a9e1 Introduce vn_path_to_global_path()
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
2012-01-15 12:08:20 +00:00
Attilio Rao
ed1f6dc235 Introduce the option VFS_ALLOW_NONMPSAFE and turn it on by default on
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
2011-11-08 10:18:07 +00:00
Ed Schouten
d745c852be Mark MALLOC_DEFINEs static that have no corresponding MALLOC_DECLAREs.
This means that their use is restricted to a single C file.
2011-11-07 06:44:47 +00:00
Kirk McKusick
cd795a6e1f When unmounting a filesystem always wait for the vfs_busy lock to clear
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
2011-10-11 18:46:41 +00:00
Kip Macy
8451d0dd78 In order to maximize the re-usability of kernel code in user space this
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)
2011-09-16 13:58:51 +00:00
Martin Matuska
d16eac5c57 Revert r224655 and r224614 because vn_fullpath* does not always work
on nullfs mounts.

Change shall be reconsidered after 9.0 is released.

Requested by:	re (kib)
Approved by:	re (kib)
2011-08-08 14:02:08 +00:00
Martin Matuska
5388625fff The change in r224615 didn't take into account that vn_fullpath_global()
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
2011-08-05 11:12:50 +00:00
Martin Matuska
f6c1d63e47 For mount, discover f_mntonname from supplied path argument
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
2011-08-02 19:13:56 +00:00
Kirk McKusick
6beb3bb4eb This update changes the mnt_flag field in the mount structure from
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)
2011-07-24 17:43:09 +00:00