Commit Graph

260 Commits

Author SHA1 Message Date
Konstantin Belousov
78022527bb Switch to use shared vnode locks for text files during image activation.
kern_execve() locks text vnode exclusive to be able to set and clear
VV_TEXT flag. VV_TEXT is mutually exclusive with the v_writecount > 0
condition.

The change removes VV_TEXT, replacing it with the condition
v_writecount <= -1, and puts v_writecount under the vnode interlock.
Each text reference decrements v_writecount.  To clear the text
reference when the segment is unmapped, it is recorded in the
vm_map_entry backed by the text file as MAP_ENTRY_VN_TEXT flag, and
v_writecount is incremented on the map entry removal

The operations like VOP_ADD_WRITECOUNT() and VOP_SET_TEXT() check that
v_writecount does not contradict the desired change.  vn_writecheck()
is now racy and its use was eliminated everywhere except access.
Atomic check for writeability and increment of v_writecount is
performed by the VOP.  vn_truncate() now increments v_writecount
around VOP_SETATTR() call, lack of which is arguably a bug on its own.

nullfs bypasses v_writecount to the lower vnode always, so nullfs
vnode has its own v_writecount correct, and lower vnode gets all
references, since object->handle is always lower vnode.

On the text vnode' vm object dealloc, the v_writecount value is reset
to zero, and deadfs vop_unset_text short-circuit the operation.
Reclamation of lowervp always reclaims all nullfs vnodes referencing
lowervp first, so no stray references are left.

Reviewed by:	markj, trasz
Tested by:	mjg, pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 month
Differential revision:	https://reviews.freebsd.org/D19923
2019-05-05 11:20:43 +00:00
Konstantin Belousov
7ae3486e6d nullfs: fix unmounts when filesystem is active.
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
2019-03-21 13:30:48 +00:00
Konstantin Belousov
b9662886ef Un null_vptocnp(), cache vp->v_mount and use it for null_nodeget() call.
The vp vnode is unlocked during the execution of the VOP method and
can be reclaimed, zeroing vp->v_data.  Caching allows to use the
correct mount point.

Reported and tested by:	pho
PR: 235549
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2019-02-08 08:20:18 +00:00
Konstantin Belousov
25728e8411 Before using VTONULL(), check that the covered vnode belongs to nullfs.
Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2019-02-08 08:17:31 +00:00
Konstantin Belousov
930cc2dbef Some style for nullfs_mount(). Also use bool type for isvnunlocked.
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2019-02-08 08:15:29 +00:00
Jamie Gritton
0e5c6bd436 Make it easier for filesystems to count themselves as jail-enabled,
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
2018-05-04 20:54:27 +00:00
Edward Tomasz Napierala
ed5cdcb6c3 Make nullfs properly report MNT_AUTOMOUNTED set on the nullfs mount itself,
instead of copying from the underlying filesystem.

PR:		224851
Reported by:	Jamie Landeg-Jones <jamie at dyslexicfish.net>
Tested by:	Jamie Landeg-Jones <jamie at dyslexicfish.net>
MFC after:	2 weeks
2018-01-10 17:51:02 +00:00
Pedro F. Giffuni
51369649b0 sys: further adoption of SPDX licensing ID tags.
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.
2017-11-20 19:43:44 +00:00
Warner Losh
fbbd9655e5 Renumber copyright clause 4
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
2017-02-28 23:42:47 +00:00
Konstantin Belousov
2f304845e2 Do not allocate struct statfs on kernel stack.
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
2017-01-05 17:19:26 +00:00
Konstantin Belousov
abc1515601 NFSv4 client tracks opens, and the track records are only dropped when
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
2016-11-27 09:20:58 +00:00
Bryan Drewery
28323add09 Fix improper use of "its".
Sponsored by:	Dell EMC Isilon
2016-11-08 23:59:41 +00:00
Edward Tomasz Napierala
e583d99909 Change the getnewvnode(9) tag for nullfs from "null" to "nullfs".
It's more consistent, and besides, the "null" alone looks weird.

MFC after:	1 month
2016-09-15 13:57:37 +00:00
Mateusz Guzik
6a3e46059a nullfs: plug vnode ref leak in null_vptocnp
The lower vnode is already referenced and nodeget is supposed to consume
the reference. Thus the extra vref call was causing a leak.

Reported by:	pho
Reviewed by:	kib
MFC after:	1 week
2016-09-09 10:40:55 +00:00
Mateusz Guzik
2740551545 nullfs: stop special-casing directories in null_vptocnp
The previous code was forcing an expensive walk in vop_stdvptocnp,
which was causing performance issues on highly contended zfs.

No objections:	kib
MFC after:	2 weeks
2016-09-06 21:22:03 +00:00
Pedro F. Giffuni
b3a15ddd5b sys/fs: spelling fixes in comments.
No functional change.
2016-04-29 20:51:24 +00:00
Konstantin Belousov
f36aa2b792 Pass MNTK_NO_IOPF and MNTK_UNMAPPED_BUFS flags from the lower
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
2016-03-04 17:24:28 +00:00
Konstantin Belousov
830cd4b810 After nullfs rmdir operation, reclaim the directory vnode which was
unlinked.  Otherwise the vnode stays cached, causing leak.  This is
similar to r292961 for regular files.

Reported and tested by:	pho (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2016-02-17 19:43:03 +00:00
Konstantin Belousov
6f73b583d9 Force nullfs vnode reclaim after unlinking, to potentially unlink
lower vnode.  Otherwise, reference to the lower vnode from the upper
one prevents final unlink.

PR:	178238
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2015-12-30 19:49:22 +00:00
Mark Johnston
5f34e93c58 Check suspendability on the mountpoint returned by VOP_GETWRITEMOUNT.
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
2015-07-05 22:37:33 +00:00
Rick Macklem
dda11d4ab9 File systems that do not use the buffer cache (such as ZFS) must
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
2015-04-15 20:16:31 +00:00
Mateusz Guzik
cd29b292b8 Convert nullfs hash lock from a mutex to an rwlock. 2014-12-30 21:41:35 +00:00
Mateusz Guzik
4fce16e4c9 Provide vfs suspension support only for filesystems which need it, take
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
2014-10-20 18:00:50 +00:00
Konstantin Belousov
effc6a3593 VOP_LOOKUP() may relock the directory vnode for some reasons. Since
nullfs vnode shares vnode lock with lower vnode, this allows the
reclamation of nullfs directory vnode in null_lookup().  In this
situation, VOP must return ENOENT.

More, since after the reclamation, the locks of nullfs directory vnode
and lower vnode are no longer shared, the relock of the ldvp does not
restore the correct locking state of dvp, and leaks ldvp lock.
Correct this by unlocking ldvp and locking dvp.

Use cached value of dvp->v_mount.

Reported by:	bdrewery
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2014-08-08 11:39:05 +00:00
Konstantin Belousov
0ebe0000b6 Assert that nullfs vnode has VV_ROOT set whenever lower vnode has.
Assert that dotdot lookup on the root vnode is not performed.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-07-28 14:20:31 +00:00
Konstantin Belousov
289dd6dd7c Fix typo.
MFC after:	3 days
2014-07-24 23:14:03 +00:00
Konstantin Belousov
65589a29f4 Check for the cross-device cross-link attempt in the VFS, instead of
forcing filesystem VOP_LINK() methods to repeat the code.  In
tmpfs_link(), remove redundand check for the type of the source,
already done by VFS.

Note that NFS server already performs this check before calling
VOP_LINK().

Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2014-07-16 14:04:46 +00:00
Dag-Erling Smørgrav
1a05c762b9 Fix the length calculation for the final block of a sendfile(2)
transmission which could be tricked into rounding up to the nearest
page size, leaking up to a page of kernel memory.  [13:11]

In IPv6 and NetATM, stop SIOCSIFADDR, SIOCSIFBRDADDR, SIOCSIFDSTADDR
and SIOCSIFNETMASK at the socket layer rather than pass them on to the
link layer without validation or credential checks.  [SA-13:12]

Prevent cross-mount hardlinks between different nullfs mounts of the
same underlying filesystem.  [SA-13:13]

Security:	CVE-2013-5666
Security:	FreeBSD-SA-13:11.sendfile
Security:	CVE-2013-5691
Security:	FreeBSD-SA-13:12.ifioctl
Security:	CVE-2013-5710
Security:	FreeBSD-SA-13:13.nullfs
Approved by:	re
2013-09-10 10:05:59 +00:00
Konstantin Belousov
18a8d3d7f8 The tvp vnode on rename is usually unlinked. Drop the cached null
vnode for tvp to allow the free of the lower vnode, if needed.

PR:	kern/180236
Tested by:	smh
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2013-07-04 19:01:18 +00:00
Konstantin Belousov
74c7ff1a0e Do not leak the NULLV_NOUNLOCK flag from the nullfs_unlink_lowervp(),
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
2013-05-21 11:31:56 +00:00
Konstantin Belousov
0fc6daa72d - Fix nullfs vnode reference leak in nullfs_reclaim_lowervp(). The
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
2013-05-11 11:17:44 +00:00
Jilles Tjoelker
6d6a91c50f nullfs: Improve f_flags in statfs().
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
2013-03-02 12:42:23 +00:00
Konstantin Belousov
e8f966eeb8 Remove the filtering of the acceptable mount options for nullfs, added
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
2013-01-16 05:32:49 +00:00
Konstantin Belousov
603f963e56 The current default size of the nullfs hash table used to lookup the
existing nullfs vnode by the lower vnode is only 16 slots.  Since the
default mode for the nullfs is to cache the vnodes, hash has extremely
huge chains.

Size the nullfs hashtbl based on the current value of
desiredvnodes. Use vfs_hash_index() to calculate the hash bucket for a
given vnode.

Pointy hat to:	    kib
Diagnosed and reviewed by:	peter
Tested by:    peter, pho (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	5 days
2013-01-14 05:44:47 +00:00
Konstantin Belousov
6b17595133 When nullfs mount is forcibly unmounted and nullfs vnode is reclaimed,
get back the leased write reference from the lower vnode.  There is no
other path which can correct v_writecount on the lowervp.

Reported by:	flo
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
2013-01-10 18:24:48 +00:00
Konstantin Belousov
268dd286a0 Fix reversed condition in the assertion.
Pointy hat to:	kib
MFC after:	13 days
2013-01-04 07:52:47 +00:00
Konstantin Belousov
9cf4c952ca Add the "nocache" nullfs mount option, which disables the caching of
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
2013-01-03 19:17:57 +00:00
Konstantin Belousov
6db79c26ce Remove the check and panic for an impossible condition. The NULL
lowervp vnode v_vnlock would cause panic due to NULL pointer
dereference much earlier.

MFC after:	1 week
2012-11-20 15:25:00 +00:00
Attilio Rao
c6e0355cee r16312 is not any longer real since many years (likely since when VFS
received granular locking) but the comment present in UFS has been
copied all over other filesystems code incorrectly for several times.

Removes comments that makes no sense now.

Reviewed by:	kib
MFC after:	3 days
2012-11-19 22:43:45 +00:00
Attilio Rao
bc2258da88 Complete MPSAFE VFS interface and remove MNTK_MPSAFE flag.
Porters should refer to __FreeBSD_version 1000021 for this change as
it may have happened at the same timeframe.
2012-11-09 18:02:25 +00:00
Konstantin Belousov
140dedb81c The r241025 fixed the case when a binary, executed from nullfs mount,
was still possible to open for write from the lower filesystem.  There
is a symmetric situation where the binary could already has file
descriptors opened for write, but it can be executed from the nullfs
overlay.

Handle the issue by passing one v_writecount reference to the lower
vnode if nullfs vnode has non-zero v_writecount.  Note that only one
write reference can be donated, since nullfs only keeps one use
reference on the lower vnode.  Always use the lower vnode v_writecount
for the checks.

Introduce the VOP_GET_WRITECOUNT to read v_writecount, which is
currently always bypassed to the lower vnode, and VOP_ADD_WRITECOUNT
to manipulate the v_writecount value, which manages a single bypass
reference to the lower vnode.  Caling the VOPs instead of directly
accessing v_writecount provide the fix described in the previous
paragraph.

Tested by:	pho
MFC after:	3 weeks
2012-11-02 13:56:36 +00:00
Konstantin Belousov
82ed933c6f Grammar fixes.
Submitted by:	bf
MFC after:	1 week
2012-10-14 18:13:33 +00:00
Konstantin Belousov
806efacae0 Replace the XXX comment with the proper description.
MFC after:	1 week
2012-10-14 17:07:34 +00:00
Konstantin Belousov
d9e9650a36 Allow shared lookups for nullfs mounts, if lower filesystem supports
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
2012-09-09 19:20:23 +00:00
Edward Tomasz Napierala
af6e6b87ad Remove unused thread argument to vrecycle().
Reviewed by:	kib
2012-04-23 14:10:34 +00:00
Kevin Lo
11753bd018 Use NULL instead of 0 2012-03-13 10:04:13 +00:00
Konstantin Belousov
66f02f4b25 Do not expose unlocked unconstructed nullfs vnode on mount list.
Lock the native nullfs vnode lock before switching the locks.

Tested by:	pho
MFC after:	1 week
2012-03-02 09:48:46 +00:00
Konstantin Belousov
37a1046e61 Allow shared locks for reads when lower filesystem accept shared locking.
Tested by:	pho
MFC after:	1 week
2012-02-29 15:18:53 +00:00
Konstantin Belousov
cec1d07726 Document that null_nodeget() cannot take shared-locked lowervp due to
insmntque() requirements.

Tested by:	pho
MFC after:	1 week
2012-02-29 15:18:04 +00:00
Konstantin Belousov
409b12c08a In null_reclaim(), assert that reclaimed vnode is fully constructed,
instead of accepting half-constructed vnode. Previous code cannot decide
what to do with such vnode anyway, and although processing it for hash
removal, paniced later when getting rid of nullfs reference on lowervp.

While there, remove initializations from the declaration block.

Tested by:	pho
MFC after:	1 week
2012-02-29 15:15:36 +00:00