Commit Graph

82 Commits

Author SHA1 Message Date
Konstantin Belousov
706f80801d The tmpfs_link() must not dereference the filesystem-specific data for
a vnode until it is verified that the vnode indeed belongs to tmpfs
mount.  Otherwise, it might access random memory, at least in the
debug kernel.

Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2014-07-14 08:45:29 +00:00
Konstantin Belousov
fca015d301 Remove code separator lines which do not conform to style(9).
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2014-07-14 08:17:11 +00:00
Konstantin Belousov
7b81a399a4 In msdosfs_setattr(), add a check for result of the utimes(2)
permissions test, forgotten in r164033.

Refactor the permission checks for utimes(2) into vnode helper
function vn_utimes_perm(9), and simplify its code comparing with the
UFS origin, by writing the call to VOP_ACCESSX only once.  Use the
helper for UFS(5), tmpfs(5), devfs(5) and msdosfs(5).

Reported by:	bde
Reviewed by:	bde, trasz
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-06-17 07:11:00 +00:00
Bryan Drewery
ac09d109ca Rename cnt to maxcookies and change its use as the condition for when to
lookup cookies to be less obscure.

No functional change.

Since r245115, cnt has not really been needed in tmpfs_dir_getdents().  Keep
it for the MPASS() for now though.

Sponsored by:	EMC / Isilon Storage Division
MFC after:	2 weeks
2014-03-14 13:55:48 +00:00
Konstantin Belousov
41cf41fdfd Extract the general-purpose code from tmpfs to perform uiomove from
the page queue of some vm object.

Discussed with:	alc
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
2013-08-21 17:23:24 +00:00
Attilio Rao
c7aebda8a1 The soft and hard busy mechanism rely on the vm object lock to work.
Unify the 2 concept into a real, minimal, sxlock where the shared
acquisition represent the soft busy and the exclusive acquisition
represent the hard busy.
The old VPO_WANTED mechanism becames the hard-path for this new lock
and it becomes per-page rather than per-object.
The vm_object lock becames an interlock for this functionality:
it can be held in both read or write mode.
However, if the vm_object lock is held in read mode while acquiring
or releasing the busy state, the thread owner cannot make any
assumption on the busy state unless it is also busying it.

Also:
- Add a new flag to directly shared busy pages while vm_page_alloc
  and vm_page_grab are being executed.  This will be very helpful
  once these functions happen under a read object lock.
- Move the swapping sleep into its own per-object flag

The KPI is heavilly changed this is why the version is bumped.
It is very likely that some VM ports users will need to change
their own code.

Sponsored by:	EMC / Isilon storage division
Discussed with:	alc
Reviewed by:	jeff, kib
Tested by:	gavin, bapt (older version)
Tested by:	pho, scottl
2013-08-09 11:11:11 +00:00
Attilio Rao
be99683637 Revert r253939:
We cannot busy a page before doing pagefaults.
Infact, it can deadlock against vnode lock, as it tries to vget().
Other functions, right now, have an opposite lock ordering, like
vm_object_sync(), which acquires the vnode lock first and then
sleeps on the busy mechanism.

Before this patch is reinserted we need to break this ordering.

Sponsored by:	EMC / Isilon storage division
Reported by:	kib
2013-08-05 08:55:35 +00:00
Attilio Rao
3b6714cacb The page hold mechanism is fast but it has couple of fallouts:
- It does not let pages respect the LRU policy
- It bloats the active/inactive queues of few pages

Try to avoid it as much as possible with the long-term target to
completely remove it.
Use the soft-busy mechanism to protect page content accesses during
short-term operations (like uiomove_fromphys()).

After this change only vm_fault_quick_hold_pages() is still using the
hold mechanism for page content access.
There is an additional complexity there as the quick path cannot
immediately access the page object to busy the page and the slow path
cannot however busy more than one page a time (to avoid deadlocks).

Fixing such primitive can bring to complete removal of the page hold
mechanism.

Sponsored by:	EMC / Isilon storage division
Discussed with:	alc
Reviewed by:	jeff
Tested by:	pho
2013-08-04 21:07:24 +00:00
Attilio Rao
878a788734 Remove unnecessary soft busy of the page before to do vn_rdwr() in
kern_sendfile() which is unnecessary.
The page is already wired so it will not be subjected to pagefault.
The content cannot be effectively protected as it is full of races
already.
Multiple accesses to the same indexes are serialized through vn_rdwr().

Sponsored by:	EMC / Isilon storage division
Reviewed by:	alc, jeff
Tested by:	pho
2013-08-04 15:56:19 +00:00
Alan Cox
f50b6721e1 Add missing VM object unlocks in an error case.
Reviewed by:	kib
2013-06-07 19:42:00 +00:00
Alan Cox
27a18d6a23 Don't busy the page unless we are likely to release the object lock.
Reviewed by:	kib
Sponsored by:	EMC / Isilon Storage Division
2013-06-06 06:17:20 +00:00
Alan Cox
ba887a9b33 Eliminate unnecessary vm object locking from tmpfs_nocacheread(). 2013-06-04 15:40:45 +00:00
Konstantin Belousov
3fa456b35d Avoid deactivating the page if it is already on a queue, only requeue
the page.  This both reduces the number of queues locking and avoids
moving the active page to inactive list just because the page was read
or written.

Based on the suggestion by:	alc
Reviewed by: alc
Tested by:   pho
2013-05-06 21:04:42 +00:00
Konstantin Belousov
df6b240b6f Fix the v_object leak for non-regular tmpfs vnodes.
Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
2013-05-02 18:46:31 +00:00
Konstantin Belousov
158cc900bb For the new regular tmpfs vnode, v_object is initialized before
insmntque() is called.  The standard insmntque destructor resets the
vop vector to deadfs one, and calls vgone() on the vnode.  As result,
v_object is kept unchanged, which triggers an assertion in the reclaim
code, on instmntque() failure.  Also, in this case, OBJ_TMPFS flag on
the backed vm object is not cleared.

Provide the tmpfs insmntque() destructor which properly clears
OBJ_TMPFS flag and resets v_object.

Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
2013-05-02 18:44:31 +00:00
Konstantin Belousov
bdefcb6959 The page read or written could be wired. Do not requeue if the page
is not on a queue.

Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
2013-05-02 18:36:52 +00:00
Konstantin Belousov
6f2af3fcf3 Rework the handling of the tmpfs node backing swap object and tmpfs
vnode v_object to avoid double-buffering.  Use the same object both as
the backing store for tmpfs node and as the v_object.

Besides reducing memory use up to 2x times for situation of mapping
files from tmpfs, it also makes tmpfs read and write operations copy
twice bytes less.

VM subsystem was already slightly adapted to tolerate OBJT_SWAP object
as v_object. Now the vm_object_deallocate() is modified to not
reinstantiate OBJ_ONEMAPPING flag and help the VFS to correctly handle
VV_TEXT flag on the last dereference of the tmpfs backing object.

Reviewed by:	alc
Tested by:	pho, bf
MFC after:	1 month
2013-04-28 19:38:59 +00:00
Pawel Jakub Dawidek
051a23d4e8 - Constify local path variable for chflagsat().
- Use correct format characters (%lx) for u_long.

This fixes the build broken in r248599.
2013-03-22 07:40:34 +00:00
Konstantin Belousov
0d3bb4afa8 Remove negative name cache entry pointing to the target name, which
could be instantiated while tdvp was unlocked.

Reported by:	Rick Miller <vmiller at hostileadmin com>
Tested by:	pho
MFC after:	1 week
2013-03-17 15:11:37 +00:00
Attilio Rao
89f6b8632c Switch the vm_object mutex to be a rwlock. This will enable in the
future further optimizations where the vm_object lock will be held
in read mode most of the time the page cache resident pool of pages
are accessed for reading purposes.

The change is mostly mechanical but few notes are reported:
* The KPI changes as follow:
  - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK()
  - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK()
  - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK()
  - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED()
    (in order to avoid visibility of implementation details)
  - The read-mode operations are added:
    VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(),
    VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED()
* The vm/vm_pager.h namespace pollution avoidance (forcing requiring
  sys/mutex.h in consumers directly to cater its inlining functions
  using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h
  consumers now must include also sys/rwlock.h.
* zfs requires a quite convoluted fix to include FreeBSD rwlocks into
  the compat layer because the name clash between FreeBSD and solaris
  versions must be avoided.
  At this purpose zfs redefines the vm_object locking functions
  directly, isolating the FreeBSD components in specific compat stubs.

The KPI results heavilly broken by this commit.  Thirdy part ports must
be updated accordingly (I can think off-hand of VirtualBox, for example).

Sponsored by:	EMC / Isilon storage division
Reviewed by:	jeff
Reviewed by:	pjd (ZFS specific review)
Discussed with:	alc
Tested by:	pho
2013-03-09 02:32:23 +00:00
Attilio Rao
5e60cb948e Remove a racy checks on resident and cached pages for
tmpfs_mapped{read, write}() functions:
- tmpfs_mapped{read, write}() are only called within VOP_{READ, WRITE}(),
  which check before-hand to work only on valid VREG vnodes.  Also the
  vnode is locked for the duration of the work, making vnode reclaiming
  impossible, during the operation. Hence, vobj can never be NULL.
- Currently check on resident pages and cached pages without vm object
  lock held is racy and can do even more harm than good, as a page could
  be transitioning between these 2 pools and then be skipped entirely.
  Skip the checks as lookups on empty splay trees are very cheap.

Discussed with:	alc
Tested by:	flo
MFC after:	2 weeks
2013-02-10 01:04:10 +00:00
Gleb Kurtsou
4fd5efe79e tmpfs: Replace directory entry linked list with RB-Tree.
Use file name hash as a tree key, handle duplicate keys.  Both VOP_LOOKUP
and VOP_READDIR operations utilize same tree for search.  Directory
entry offset (cookie) is either file name hash or incremental id in case
of hash collisions (duplicate-cookies).  Keep sorted per directory list
of duplicate-cookie entries to facilitate cookie number allocation.

Don't fail if previous VOP_READDIR() offset is no longer valid, start
with next dirent instead.  Other file system handle it similarly.

Workaround race prone tn_readdir_last[pn] fields update.

Add tmpfs_dir_destroy() to free all dirents.

Set NFS cookies in tmpfs_dir_getdents(). Return EJUSTRETURN from
tmpfs_dir_getdents() instead of hard coded -1.

Mark directory traversal routines static as they are no longer
used outside of tmpfs_subr.c
2013-01-06 22:15:44 +00:00
Konstantin Belousov
1c771f9222 After the PHYS_TO_VM_PAGE() function was de-inlined, the main reason
to pull vm_param.h was removed.  Other big dependency of vm_page.h on
vm_param.h are PA_LOCK* definitions, which are only needed for
in-kernel code, because modules use KBI-safe functions to lock the
pages.

Stop including vm_param.h into vm_page.h. Include vm_param.h
explicitely for the kernel code which needs it.

Suggested and reviewed by:	alc
MFC after:    2 weeks
2012-08-05 14:11:42 +00:00
Edward Tomasz Napierala
af6e6b87ad Remove unused thread argument to vrecycle().
Reviewed by:	kib
2012-04-23 14:10:34 +00:00
Attilio Rao
a0f2c37b6f - Introduce a cache-miss optimization for consistency with other
accesses of the cache member of vm_object objects.
- Use novel vm_page_is_cached() for checks outside of the vm subsystem.

Reviewed by:	alc
MFC after:	2 weeks
X-MFC:		r234039
2012-04-09 17:05:18 +00:00
Gleb Kurtsou
db94ad126a Prevent tmpfs_rename() deadlock in a way similar to UFS
Unlock vnodes and try to lock them one by one. Relookup fvp and tvp.

Approved by:	mdf (mentor)
2012-03-14 09:15:50 +00:00
Konstantin Belousov
b80dcb55aa Remove fifo.h. The only used function declaration from the header is
migrated to sys/vnode.h.

Submitted by:	gianni
2012-03-11 12:19:58 +00:00
John Baldwin
58d65e8031 Similar to the fixes in 226967 and 226987, purge any name cache entries
associated with the previous vnode (if any) associated with the target of
a rename().  Otherwise, a lookup of the target pathname concurrent with a
rename() could re-add a name cache entry after the namei(RENAME) lookup
in kern_renameat() had purged the target pathname.

MFC after:	2 weeks
2012-03-02 18:55:19 +00:00
Tijl Coosemans
0662ee9826 Replace PRIdMAX with "jd" in a printf call. Cast the corresponding value to
intmax_t instead of uintmax_t, because the original type is off_t.
2012-02-14 11:24:24 +00:00
Alan Cox
0b05cac3d2 When tmpfs_write() resets an extended file to its original size after an
error, we want tmpfs_reg_resize() to ignore I/O errors and unconditionally
update the file's size.

Reviewed by:	kib
MFC after:	3 weeks
2012-01-16 00:26:49 +00:00
Alan Cox
93431cb74c Neither tmpfs_nocacheread() nor tmpfs_mappedwrite() needs to call
vm_object_pip_{add,subtract}() on the swap object because the swap
object can't be destroyed while the vnode is exclusively locked.
Moreover, even if the swap object could have been destroyed during
tmpfs_nocacheread() and tmpfs_mappedwrite() this code is broken
because vm_object_pip_subtract() does not wake up the sleeping thread
that is trying to destroy the swap object.

Free invalid pages after an I/O error.  There is no virtue in keeping
them around in the swap object creating more work for the page daemon.
(I believe that any non-busy page in the swap object will now always
be valid.)

vm_pager_get_pages() does not return a standard errno, so its return
value should not be returned by tmpfs without translation to an errno
value.

There is no reason for the wakeup on vpg in tmpfs_mappedwrite() to
occur with the swap object locked.

Eliminate printf()s from tmpfs_nocacheread() and tmpfs_mappedwrite().
(The swap pager already spam your console if data corruption is
imminent.)

Reviewed by:	kib
MFC after:	3 weeks
2012-01-14 23:04:27 +00:00
Alan Cox
04f883d798 Don't pass VM_ALLOC_ZERO to vm_page_grab() in tmpfs_mappedwrite() and
tmpfs_nocacheread().  It is both unnecessary and a pessimization.  It
results in either the page being zeroed twice or zeroed first and then
overwritten by an I/O operation.

MFC after:	3 weeks
2012-01-03 03:29:01 +00:00
Ivan Voras
6e92aee4e2 Avoid panics from recursive rename operations. Not a perfect patch but
good enough for now.

PR:		kern/159418
Submitted by:	Gleb Kurtsou
Reviewed by:	kib
MFC after:	1 month
2011-11-22 16:18:12 +00:00
Peter Holm
948fa27d49 Added missing cache purge of from argument for rename().
Reported by:	Anton Yuzhaninov <citrin citrin ru>
In collaboration with:	kib
MFC after:	1 week
2011-11-01 12:33:06 +00:00
Konstantin Belousov
3407fefef6 Split the vm_page flags PG_WRITEABLE and PG_REFERENCED into atomic
flags field. Updates to the atomic flags are performed using the atomic
ops on the containing word, do not require any vm lock to be held, and
are non-blocking. The vm_page_aflag_set(9) and vm_page_aflag_clear(9)
functions are provided to modify afalgs.

Document the changes to flags field to only require the page lock.

Introduce vm_page_reference(9) function to provide a stable KPI and
KBI for filesystems like tmpfs and zfs which need to mark a page as
referenced.

Reviewed by:    alc, attilio
Tested by:      marius, flo (sparc64); andreast (powerpc, powerpc64)
Approved by:	re (bz)
2011-09-06 10:30:11 +00:00
Alan Cox
4d2f3d2cde Eliminate two dubious attempts at optimizing the implementation of a
file's last accessed, modified, and changed times:

TMPFS_NODE_ACCESSED and TMPFS_NODE_CHANGED should be set unconditionally
in tmpfs_remove() without regard to the number of hard links to the file.
Otherwise, after the last directory entry for a file has been removed, a
process that still has the file open could read stale values for the last
accessed and changed times with fstat(2).

Similarly, tmpfs_close() should update the time-related fields even if all
directory entries for a file have been removed.  In this case, the effect
is that the time-related fields will have values that are later than
expected.  They will correspond to the time at which fstat(2) is called.

In collaboration with:	kib
MFC after:	1 week
2011-02-22 14:47:10 +00:00
Alan Cox
7ded42ba28 tmpfs_remove() isn't modifying the file's data, so it shouldn't set
TMPFS_NODE_MODIFIED on the node.

PR:		152488
Submitted by:	Anton Yuzhaninov
Reviewed by:	kib
MFC after:	1 week
2011-02-19 21:04:36 +00:00
Konstantin Belousov
9fb9c623a6 In tmpfs_readdir(), normalize handling of the directory entries that
either overflow the supplied buffer, or cause uiomove fail.
Do not advance cached de when directory entry was not copied out.
Do not return EOF when no entries could be copied due to first entry
too large for supplied buffer, signal EINVAL instead.

Reported by:	Beat G?tzi <beat chruetertee ch>
MFC after:	1 week
2011-01-20 09:39:16 +00:00
Andriy Gapon
e07b64c567 tmpfs + sendfile: do not produce partially valid pages for vnode's tail
See r213730 for details of analogous change in ZFS.

MFC after:	3 days
2010-10-12 17:16:51 +00:00
Andriy Gapon
21bd3e2576 tmpfs, zfs + sendfile: mark page bits as valid after populating it with data
Otherwise, adding insult to injury, in addition to double-caching of data
we would always copy the data into a vnode's vm object page from backend.
This is specific to sendfile case only (VOP_READ with UIO_NOCOPY).

PR:		kern/141305
Reported by:	Wiktor Niesiobedzki <bsd@vink.pl>
Reviewed by:	alc
Tested by:	tools/regression/sockets/sendfile
MFC after:	2 weeks
2010-09-15 10:31:27 +00:00
Ivan Voras
b2143ecb99 Avoid "Entry can disappear before we lock fdvp" panic.
PR:		150143
Submitted by:	Gleb Kurtsou <gk at FreeBSD.org>
Pretty sure it won't blow up: mckusick
MFC after:	2 weeks
2010-09-07 22:40:45 +00:00
Ed Schouten
99d57a6bd8 Add support for whiteouts on tmpfs.
Right now unionfs only allows filesystems to be mounted on top of
another if it supports whiteouts. Even though I have sent a patch to
daichi@ to let unionfs work without it, we'd better also add support for
whiteouts to tmpfs.

This patch implements .vop_whiteout and makes necessary changes to
lookup() and readdir() to take them into account. We must also make sure
that when adding or removing a file, we honour the componentname's
DOWHITEOUT and ISWHITEOUT, to prevent duplicate filenames.

MFC after:	1 month
2010-08-22 05:36:06 +00:00
Alan Cox
8393d186b9 Eliminate unnecessary page queues locking. 2010-06-16 00:41:21 +00:00
Edward Tomasz Napierala
307d88b787 Style fixes and removal of unneeded variable.
Submitted by:	bde@
2010-05-06 18:43:19 +00:00
Edward Tomasz Napierala
b5f770bd86 Move checking against RLIMIT_FSIZE into one place, vn_rlimit_fsize().
Reviewed by:	kib
2010-05-05 16:44:25 +00:00
Alan Cox
e3ef0d2fcf Push down the acquisition of the page queues lock into vm_page_unwire().
Update the comment describing which lock should be held on entry to
vm_page_wire().

Reviewed by:	kib
2010-05-05 03:45:46 +00:00
Alan Cox
c5a648516e Acquire the page lock around vm_page_unwire() and vm_page_wire().
Reviewed by:	kib
2010-05-03 16:41:11 +00:00
Alan Cox
b88b6c9d80 It makes no sense for vm_page_sleep_if_busy()'s helper, vm_page_sleep(),
to unconditionally set PG_REFERENCED on a page before sleeping.  In many
cases, it's perfectly ok for the page to disappear, i.e., be reclaimed by
the page daemon, before the caller to vm_page_sleep() is reawakened.
Instead, we now explicitly set PG_REFERENCED in those cases where having
the page persist until the caller is awakened is clearly desirable.  Note,
however, that setting PG_REFERENCED on the page is still only a hint,
and not a guarantee that the page should persist.
2010-05-02 17:33:46 +00:00
Xin LI
82cf92d483 Add locking around access to parent node, and bail out when the parent
node is already freed rather than panicking the system.

PR:		kern/122038
Submitted by:	gk
Tested by:	pho
MFC after:	1 week
2009-10-11 07:03:56 +00:00
Xin LI
3fa0694aaa Add a special workaround to handle UIO_NOCOPY case. This fixes data
corruption observed when sendfile() is being used.

PR:		kern/127213
Submitted by:	gk
MFC after:	2 weeks
2009-10-07 23:17:15 +00:00