Commit Graph

630 Commits

Author SHA1 Message Date
Anton Altaparmakov af5eb745ef NTFS: Fix invalid pointer dereference in ntfs_mft_record_alloc().
In ntfs_mft_record_alloc() when mapping the new extent mft record with
map_extent_mft_record() we overwrite @m with the return value and on
error, we then try to use the old @m but that is no longer there as @m
now contains an error code instead so we crash when dereferencing the
error code as if it were a pointer.

The simple fix is to use a temporary variable to store the return value
thus preserving the original @m for later use.  This is a backport from
the commercial Tuxera-NTFS driver and is well tested...

Thanks go to Julia Lawall for pointing this out (whilst I had fixed it
in the commercial driver I had failed to fix it in the Linux kernel).

Signed-off-by: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-31 12:58:11 +10:00
Christoph Hellwig 2fe17c1075 fallocate should be a file operation
Currently all filesystems except XFS implement fallocate asynchronously,
while XFS forced a commit.  Both of these are suboptimal - in case of O_SYNC
I/O we really want our allocation on disk, especially for the !KEEP_SIZE
case where we actually grow the file with user-visible zeroes.  On the
other hand always commiting the transaction is a bad idea for fast-path
uses of fallocate like for example in recent Samba versions.   Given
that block allocation is a data plane operation anyway change it from
an inode operation to a file operation so that we have the file structure
available that lets us check for O_SYNC.

This also includes moving the code around for a few of the filesystems,
and remove the already unnedded S_ISDIR checks given that we only wire
up fallocate for regular files.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-17 02:25:31 -05:00
Linus Torvalds f8206b925f Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (23 commits)
  sanitize vfsmount refcounting changes
  fix old umount_tree() breakage
  autofs4: Merge the remaining dentry ops tables
  Unexport do_add_mount() and add in follow_automount(), not ->d_automount()
  Allow d_manage() to be used in RCU-walk mode
  Remove a further kludge from __do_follow_link()
  autofs4: Bump version
  autofs4: Add v4 pseudo direct mount support
  autofs4: Fix wait validation
  autofs4: Clean up autofs4_free_ino()
  autofs4: Clean up dentry operations
  autofs4: Clean up inode operations
  autofs4: Remove unused code
  autofs4: Add d_manage() dentry operation
  autofs4: Add d_automount() dentry operation
  Remove the automount through follow_link() kludge code from pathwalk
  CIFS: Use d_automount() rather than abusing follow_link()
  NFS: Use d_automount() rather than abusing follow_link()
  AFS: Use d_automount() rather than abusing follow_link()
  Add an AT_NO_AUTOMOUNT flag to suppress terminal automount
  ...
2011-01-16 11:31:50 -08:00
David Howells ea5b778a8b Unexport do_add_mount() and add in follow_automount(), not ->d_automount()
Unexport do_add_mount() and make ->d_automount() return the vfsmount to be
added rather than calling do_add_mount() itself.  follow_automount() will then
do the addition.

This slightly complicates things as ->d_automount() normally wants to add the
new vfsmount to an expiration list and start an expiration timer.  The problem
with that is that the vfsmount will be deleted if it has a refcount of 1 and
the timer will not repeat if the expiration list is empty.

To this end, we require the vfsmount to be returned from d_automount() with a
refcount of (at least) 2.  One of these refs will be dropped unconditionally.
In addition, follow_automount() must get a 3rd ref around the call to
do_add_mount() lest it eat a ref and return an error, leaving the mount we
have open to being expired as we would otherwise have only 1 ref on it.

d_automount() should also add the the vfsmount to the expiration list (by
calling mnt_set_expiry()) and start the expiration timer before returning, if
this mechanism is to be used.  The vfsmount will be unlinked from the
expiration list by follow_automount() if do_add_mount() fails.

This patch also fixes the call to do_add_mount() for AFS to propagate the mount
flags from the parent vfsmount.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-15 20:07:48 -05:00
David Howells ab90911ff9 Allow d_manage() to be used in RCU-walk mode
Allow d_manage() to be called from pathwalk when it is in RCU-walk mode as well
as when it is in Ref-walk mode.  This permits __follow_mount_rcu() to call
d_manage() directly.  d_manage() needs a parameter to indicate that it is in
RCU-walk mode as it isn't allowed to sleep if in that mode (but should return
-ECHILD instead).

autofs4_d_manage() can then be set to retain RCU-walk mode if the daemon
accesses it and otherwise request dropping back to ref-walk mode.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-15 20:07:47 -05:00
David Howells cc53ce53c8 Add a dentry op to allow processes to be held during pathwalk transit
Add a dentry op (d_manage) to permit a filesystem to hold a process and make it
sleep when it tries to transit away from one of that filesystem's directories
during a pathwalk.  The operation is keyed off a new dentry flag
(DCACHE_MANAGE_TRANSIT).

The filesystem is allowed to be selective about which processes it holds and
which it permits to continue on or prohibits from transiting from each flagged
directory.  This will allow autofs to hold up client processes whilst letting
its userspace daemon through to maintain the directory or the stuff behind it
or mounted upon it.

The ->d_manage() dentry operation:

	int (*d_manage)(struct path *path, bool mounting_here);

takes a pointer to the directory about to be transited away from and a flag
indicating whether the transit is undertaken by do_add_mount() or
do_move_mount() skipping through a pile of filesystems mounted on a mountpoint.

It should return 0 if successful and to let the process continue on its way;
-EISDIR to prohibit the caller from skipping to overmounted filesystems or
automounting, and to use this directory; or some other error code to return to
the user.

->d_manage() is called with namespace_sem writelocked if mounting_here is true
and no other locks held, so it may sleep.  However, if mounting_here is true,
it may not initiate or wait for a mount or unmount upon the parameter
directory, even if the act is actually performed by userspace.

Within fs/namei.c, follow_managed() is extended to check with d_manage() first
on each managed directory, before transiting away from it or attempting to
automount upon it.

follow_down() is renamed follow_down_one() and should only be used where the
filesystem deliberately intends to avoid management steps (e.g. autofs).

A new follow_down() is added that incorporates the loop done by all other
callers of follow_down() (do_add/move_mount(), autofs and NFSD; whilst AFS, NFS
and CIFS do use it, their use is removed by converting them to use
d_automount()).  The new follow_down() calls d_manage() as appropriate.  It
also takes an extra parameter to indicate if it is being called from mount code
(with namespace_sem writelocked) which it passes to d_manage().  follow_down()
ignores automount points so that it can be used to mount on them.

__follow_mount_rcu() is made to abort rcu-walk mode if it hits a directory with
DCACHE_MANAGE_TRANSIT set on the basis that we're probably going to have to
sleep.  It would be possible to enter d_manage() in rcu-walk mode too, and have
that determine whether to abort or not itself.  That would allow the autofs
daemon to continue on in rcu-walk mode.

Note that DCACHE_MANAGE_TRANSIT on a directory should be cleared when it isn't
required as every tranist from that directory will cause d_manage() to be
invoked.  It can always be set again when necessary.

==========================
WHAT THIS MEANS FOR AUTOFS
==========================

Autofs currently uses the lookup() inode op and the d_revalidate() dentry op to
trigger the automounting of indirect mounts, and both of these can be called
with i_mutex held.

autofs knows that the i_mutex will be held by the caller in lookup(), and so
can drop it before invoking the daemon - but this isn't so for d_revalidate(),
since the lock is only held on _some_ of the code paths that call it.  This
means that autofs can't risk dropping i_mutex from its d_revalidate() function
before it calls the daemon.

The bug could manifest itself as, for example, a process that's trying to
validate an automount dentry that gets made to wait because that dentry is
expired and needs cleaning up:

	mkdir         S ffffffff8014e05a     0 32580  24956
	Call Trace:
	 [<ffffffff885371fd>] :autofs4:autofs4_wait+0x674/0x897
	 [<ffffffff80127f7d>] avc_has_perm+0x46/0x58
	 [<ffffffff8009fdcf>] autoremove_wake_function+0x0/0x2e
	 [<ffffffff88537be6>] :autofs4:autofs4_expire_wait+0x41/0x6b
	 [<ffffffff88535cfc>] :autofs4:autofs4_revalidate+0x91/0x149
	 [<ffffffff80036d96>] __lookup_hash+0xa0/0x12f
	 [<ffffffff80057a2f>] lookup_create+0x46/0x80
	 [<ffffffff800e6e31>] sys_mkdirat+0x56/0xe4

versus the automount daemon which wants to remove that dentry, but can't
because the normal process is holding the i_mutex lock:

	automount     D ffffffff8014e05a     0 32581      1              32561
	Call Trace:
	 [<ffffffff80063c3f>] __mutex_lock_slowpath+0x60/0x9b
	 [<ffffffff8000ccf1>] do_path_lookup+0x2ca/0x2f1
	 [<ffffffff80063c89>] .text.lock.mutex+0xf/0x14
	 [<ffffffff800e6d55>] do_rmdir+0x77/0xde
	 [<ffffffff8005d229>] tracesys+0x71/0xe0
	 [<ffffffff8005d28d>] tracesys+0xd5/0xe0

which means that the system is deadlocked.

This patch allows autofs to hold up normal processes whilst the daemon goes
ahead and does things to the dentry tree behind the automouter point without
risking a deadlock as almost no locks are held in d_manage() and none in
d_automount().

Signed-off-by: David Howells <dhowells@redhat.com>
Was-Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-15 20:07:31 -05:00
David Howells 9875cf8064 Add a dentry op to handle automounting rather than abusing follow_link()
Add a dentry op (d_automount) to handle automounting directories rather than
abusing the follow_link() inode operation.  The operation is keyed off a new
dentry flag (DCACHE_NEED_AUTOMOUNT).

This also makes it easier to add an AT_ flag to suppress terminal segment
automount during pathwalk and removes the need for the kludge code in the
pathwalk algorithm to handle directories with follow_link() semantics.

The ->d_automount() dentry operation:

	struct vfsmount *(*d_automount)(struct path *mountpoint);

takes a pointer to the directory to be mounted upon, which is expected to
provide sufficient data to determine what should be mounted.  If successful, it
should return the vfsmount struct it creates (which it should also have added
to the namespace using do_add_mount() or similar).  If there's a collision with
another automount attempt, NULL should be returned.  If the directory specified
by the parameter should be used directly rather than being mounted upon,
-EISDIR should be returned.  In any other case, an error code should be
returned.

The ->d_automount() operation is called with no locks held and may sleep.  At
this point the pathwalk algorithm will be in ref-walk mode.

Within fs/namei.c itself, a new pathwalk subroutine (follow_automount()) is
added to handle mountpoints.  It will return -EREMOTE if the automount flag was
set, but no d_automount() op was supplied, -ELOOP if we've encountered too many
symlinks or mountpoints, -EISDIR if the walk point should be used without
mounting and 0 if successful.  The path will be updated to point to the mounted
filesystem if a successful automount took place.

__follow_mount() is replaced by follow_managed() which is more generic
(especially with the patch that adds ->d_manage()).  This handles transits from
directories during pathwalk, including automounting and skipping over
mountpoints (and holding processes with the next patch).

__follow_mount_rcu() will jump out of RCU-walk mode if it encounters an
automount point with nothing mounted on it.

follow_dotdot*() does not handle automounts as you don't want to trigger them
whilst following "..".

I've also extracted the mount/don't-mount logic from autofs4 and included it
here.  It makes the mount go ahead anyway if someone calls open() or creat(),
tries to traverse the directory, tries to chdir/chroot/etc. into the directory,
or sticks a '/' on the end of the pathname.  If they do a stat(), however,
they'll only trigger the automount if they didn't also say O_NOFOLLOW.

I've also added an inode flag (S_AUTOMOUNT) so that filesystems can mark their
inodes as automount points.  This flag is automatically propagated to the
dentry as DCACHE_NEED_AUTOMOUNT by __d_instantiate().  This saves NFS and could
save AFS a private flag bit apiece, but is not strictly necessary.  It would be
preferable to do the propagation in d_set_d_op(), but that doesn't normally
have access to the inode.

[AV: fixed breakage in case if __follow_mount_rcu() fails and nameidata_drop_rcu()
succeeds in RCU case of do_lookup(); we need to fall through to non-RCU case after
that, rather than just returning with ungrabbed *path]

Signed-off-by: David Howells <dhowells@redhat.com>
Was-Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-15 20:05:03 -05:00
Linus Torvalds 18bce371ae Merge branch 'for-2.6.38' of git://linux-nfs.org/~bfields/linux
* 'for-2.6.38' of git://linux-nfs.org/~bfields/linux: (62 commits)
  nfsd4: fix callback restarting
  nfsd: break lease on unlink, link, and rename
  nfsd4: break lease on nfsd setattr
  nfsd: don't support msnfs export option
  nfsd4: initialize cb_per_client
  nfsd4: allow restarting callbacks
  nfsd4: simplify nfsd4_cb_prepare
  nfsd4: give out delegations more quickly in 4.1 case
  nfsd4: add helper function to run callbacks
  nfsd4: make sure sequence flags are set after destroy_session
  nfsd4: re-probe callback on connection loss
  nfsd4: set sequence flag when backchannel is down
  nfsd4: keep finer-grained callback status
  rpc: allow xprt_class->setup to return a preexisting xprt
  rpc: keep backchannel xprt as long as server connection
  rpc: move sk_bc_xprt to svc_xprt
  nfsd4: allow backchannel recovery
  nfsd4: support BIND_CONN_TO_SESSION
  nfsd4: modify session list under cl_lock
  Documentation: fl_mylease no longer exists
  ...

Fix up conflicts in fs/nfsd/vfs.c with the vfs-scale work.  The
vfs-scale work touched some msnfs cases, and this merge removes support
for that entirely, so the conflict was trivial to resolve.
2011-01-14 13:17:26 -08:00
Linus Torvalds db9effe99a Merge branch 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin
* 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin:
  fs: fix do_last error case when need_reval_dot
  nfs: add missing rcu-walk check
  fs: hlist UP debug fixup
  fs: fix dropping of rcu-walk from force_reval_path
  fs: force_reval_path drop rcu-walk before d_invalidate
  fs: small rcu-walk documentation fixes

Fixed up trivial conflicts in Documentation/filesystems/porting
2011-01-13 20:14:13 -08:00
Nick Piggin a82416da83 fs: small rcu-walk documentation fixes
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-14 02:26:53 +00:00
Mandeep Singh Baines dabb16f639 oom: allow a non-CAP_SYS_RESOURCE proces to oom_score_adj down
We'd like to be able to oom_score_adj a process up/down as it
enters/leaves the foreground.  Currently, it is not possible to oom_adj
down without CAP_SYS_RESOURCE.  This patch allows a task to decrease its
oom_score_adj back to the value that a CAP_SYS_RESOURCE thread set it to
or its inherited value at fork.  Assuming the thread that has forked it
has oom_score_adj of 0, each process could decrease it back from 0 upon
activation unless a CAP_SYS_RESOURCE thread elevated it to something
higher.

Alternative considered:

* a setuid binary
* a daemon with CAP_SYS_RESOURCE

Since you don't wan't all processes to be able to reduce their oom_adj, a
setuid or daemon implementation would be complex.  The alternatives also
have much higher overhead.

This patch updated from original patch based on feedback from David
Rientjes.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:35 -08:00
Nikanth Karthikesan 2d90508f63 mm: smaps: export mlock information
Currently there is no way to find whether a process has locked its pages
in memory or not.  And which of the memory regions are locked in memory.

Add a new field "Locked" to export this information via the smaps file.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:33 -08:00
Linus Torvalds b2034d474b Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (41 commits)
  fs: add documentation on fallocate hole punching
  Gfs2: fail if we try to use hole punch
  Btrfs: fail if we try to use hole punch
  Ext4: fail if we try to use hole punch
  Ocfs2: handle hole punching via fallocate properly
  XFS: handle hole punching via fallocate properly
  fs: add hole punching to fallocate
  vfs: pass struct file to do_truncate on O_TRUNC opens (try #2)
  fix signedness mess in rw_verify_area() on 64bit architectures
  fs: fix kernel-doc for dcache::prepend_path
  fs: fix kernel-doc for dcache::d_validate
  sanitize ecryptfs ->mount()
  switch afs
  move internal-only parts of ncpfs headers to fs/ncpfs
  switch ncpfs
  switch 9p
  pass default dentry_operations to mount_pseudo()
  switch hostfs
  switch affs
  switch configfs
  ...
2011-01-13 10:27:28 -08:00
Josef Bacik 924241575a fs: add documentation on fallocate hole punching
This patch simply adds documentation on how to handle the hole punching mode of
fallocate for any filesystem wishing to use it.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-12 20:19:03 -05:00
Anton Altaparmakov 2818ef50c4 NTFS: writev() fix and maintenance/contact details update
Fix writev() to not keep writing the first segment over and over again
instead of moving onto subsequent segments and update the NTFS entry in
MAINTAINERS to reflect that Tuxera Inc. now supports the NTFS driver.

Signed-off-by: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12 08:35:53 -08:00
J. Bruce Fields ec26fba40f Documentation: fl_mylease no longer exists
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-11 15:04:09 -05:00
Linus Torvalds 56b85f32d5 Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6
* 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6: (36 commits)
  serial: apbuart: Fixup apbuart_console_init()
  TTY: Add tty ioctl to figure device node of the system console.
  tty: add 'active' sysfs attribute to tty0 and console device
  drivers: serial: apbuart: Handle OF failures gracefully
  Serial: Avoid unbalanced IRQ wake disable during resume
  tty: fix typos/errors in tty_driver.h comments
  pch_uart : fix warnings for 64bit compile
  8250: fix uninitialized FIFOs
  ip2: fix compiler warning on ip2main_pci_tbl
  specialix: fix compiler warning on specialix_pci_tbl
  rocket: fix compiler warning on rocket_pci_ids
  8250: add a UPIO_DWAPB32 for 32 bit accesses
  8250: use container_of() instead of casting
  serial: omap-serial: Add support for kernel debugger
  serial: fix pch_uart kconfig & build
  drivers: char: hvc: add arm JTAG DCC console support
  RS485 documentation: add 16C950 UART description
  serial: ifx6x60: fix memory leak
  serial: ifx6x60: free IRQ on error
  Serial: EG20T: add PCH_UART driver
  ...

Fixed up conflicts in drivers/serial/apbuart.c with evil merge that
makes the code look fairly sane (unlike either side).
2011-01-07 14:39:20 -08:00
Nick Piggin b74c79e993 fs: provide rcu-walk aware permission i_ops
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:29 +11:00
Nick Piggin 34286d6662 fs: rcu-walk aware d_revalidate method
Require filesystems be aware of .d_revalidate being called in rcu-walk
mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning
-ECHILD from all implementations.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:29 +11:00
Nick Piggin 31e6b01f41 fs: rcu-walk for path lookup
Perform common cases of path lookups without any stores or locking in the
ancestor dentry elements. This is called rcu-walk, as opposed to the current
algorithm which is a refcount based walk, or ref-walk.

This results in far fewer atomic operations on every path element,
significantly improving path lookup performance. It also avoids cacheline
bouncing on common dentries, significantly improving scalability.

The overall design is like this:
* LOOKUP_RCU is set in nd->flags, which distinguishes rcu-walk from ref-walk.
* Take the RCU lock for the entire path walk, starting with the acquiring
  of the starting path (eg. root/cwd/fd-path). So now dentry refcounts are
  not required for dentry persistence.
* synchronize_rcu is called when unregistering a filesystem, so we can
  access d_ops and i_ops during rcu-walk.
* Similarly take the vfsmount lock for the entire path walk. So now mnt
  refcounts are not required for persistence. Also we are free to perform mount
  lookups, and to assume dentry mount points and mount roots are stable up and
  down the path.
* Have a per-dentry seqlock to protect the dentry name, parent, and inode,
  so we can load this tuple atomically, and also check whether any of its
  members have changed.
* Dentry lookups (based on parent, candidate string tuple) recheck the parent
  sequence after the child is found in case anything changed in the parent
  during the path walk.
* inode is also RCU protected so we can load d_inode and use the inode for
  limited things.
* i_mode, i_uid, i_gid can be tested for exec permissions during path walk.
* i_op can be loaded.

When we reach the destination dentry, we lock it, recheck lookup sequence,
and increment its refcount and mountpoint refcount. RCU and vfsmount locks
are dropped. This is termed "dropping rcu-walk". If the dentry refcount does
not match, we can not drop rcu-walk gracefully at the current point in the
lokup, so instead return -ECHILD (for want of a better errno). This signals the
path walking code to re-do the entire lookup with a ref-walk.

Aside from the final dentry, there are other situations that may be encounted
where we cannot continue rcu-walk. In that case, we drop rcu-walk (ie. take
a reference on the last good dentry) and continue with a ref-walk. Again, if
we can drop rcu-walk gracefully, we return -ECHILD and do the whole lookup
using ref-walk. But it is very important that we can continue with ref-walk
for most cases, particularly to avoid the overhead of double lookups, and to
gain the scalability advantages on common path elements (like cwd and root).

The cases where rcu-walk cannot continue are:
* NULL dentry (ie. any uncached path element)
* parent with d_inode->i_op->permission or ACLs
* dentries with d_revalidate
* Following links

In future patches, permission checks and d_revalidate become rcu-walk aware. It
may be possible eventually to make following links rcu-walk aware.

Uncached path elements will always require dropping to ref-walk mode, at the
very least because i_mutex needs to be grabbed, and objects allocated.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:27 +11:00
Nick Piggin fa0d7e3de6 fs: icache RCU free inodes
RCU free the struct inode. This will allow:

- Subsequent store-free path walking patch. The inode must be consulted for
  permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
  to take i_lock no longer need to take sb_inode_list_lock to walk the list in
  the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
  page lock to follow page->mapping.

The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.

In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.

The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:26 +11:00
Nick Piggin b5c84bf6f6 fs: dcache remove dcache_lock
dcache_lock no longer protects anything. remove it.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:23 +11:00
Nick Piggin b1e6a015a5 fs: change d_hash for rcu-walk
Change d_hash so it may be called from lock-free RCU lookups. See similar
patch for d_compare for details.

For in-tree filesystems, this is just a mechanical change.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:20 +11:00
Nick Piggin 621e155a35 fs: change d_compare for rcu-walk
Change d_compare so it may be called from lock-free RCU lookups. This
does put significant restrictions on what may be done from the callback,
however there don't seem to have been any problems with in-tree fses.
If some strange use case pops up that _really_ cannot cope with the
rcu-walk rules, we can just add new rcu-unaware callbacks, which would
cause name lookup to drop out of rcu-walk mode.

For in-tree filesystems, this is just a mechanical change.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:19 +11:00
Nick Piggin fe15ce446b fs: change d_delete semantics
Change d_delete from a dentry deletion notification to a dentry caching
advise, more like ->drop_inode. Require it to be constant and idempotent,
and not take d_lock. This is how all existing filesystems use the callback
anyway.

This makes fine grained dentry locking of dput and dentry lru scanning
much simpler.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:18 +11:00
Christoph Hellwig 8a87694ed1 remove trim_fs method from Documentation/filesystems/Locking
The ->trim_fs has been removed meanwhile, so remove it from the documentation
as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-04 11:01:09 -08:00
Christoph Hellwig b83be6f20a update Documentation/filesystems/Locking
Mostly inspired by all the recent BKL removal changes, but a lot of older
updates also weren't properly recorded.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-30 10:00:50 -08:00
Linus Torvalds 38971ce2fa Merge branch 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
  NFS: Fix panic after nfs_umount()
  nfs: remove extraneous and problematic calls to nfs_clear_request
  nfs: kernel should return EPROTONOSUPPORT when not support NFSv4
  NFS: Fix fcntl F_GETLK not reporting some conflicts
  nfs: Discard ACL cache on mode update
  NFS: Readdir cleanups
  NFS: nfs_readdir_search_for_cookie() don't mark as eof if cookie not found
  NFS: Fix a memory leak in nfs_readdir
  Call the filesystem back whenever a page is removed from the page cache
  NFS: Ensure we use the correct cookie in nfs_readdir_xdr_filler
2010-12-14 08:51:12 -08:00
Andrew Morton 4fe65cab84 Documentation/filesystems/vfs.txt: fix ->repeasepage() description
->releasepage() does not remove the page from the mapping.

Acked-by: Neil Brown <neilb@suse.de>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-02 14:51:15 -08:00
Linus Torvalds 6072d13c42 Call the filesystem back whenever a page is removed from the page cache
NFS needs to be able to release objects that are stored in the page
cache once the page itself is no longer visible from the page cache.

This patch adds a callback to the address space operations that allows
filesystems to perform page cleanups once the page has been removed
from the page cache.

Original patch by: Linus Torvalds <torvalds@linux-foundation.org>
[trondmy: cover the cases of invalidate_inode_pages2() and
          truncate_inode_pages()]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2010-12-02 09:55:21 -05:00
Dan Carpenter 09c9feb946 Documentation: make configfs example code simpler, clearer
If "p" is NULL then it will cause an oops when we pass it to
simple_strtoul().  In this case "p" can not be NULL so I removed the
check.  I also changed the check a little to make it more explicit that
we are testing whether p points to the NUL char.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-18 15:00:46 -08:00
Jiri Slaby 23308ba54d console: add /proc/consoles
It allows users to see what consoles are currently known to the system
and with what flags.

It is based on Werner's patch, the part about traversing fds was
removed, the code was moved to kernel/printk.c, where consoles are
handled and it makes more sense to me.

Signed-off-by: Jiri Slaby <jslaby@suse.cz> [cleanups]
Signed-off-by: "Dr. Werner Fink" <werner@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-11-16 12:50:17 -08:00
Christoph Hellwig 5d0af85cd0 xfs: remove experimental tag from the delaylog option
We promised to do this for 2.6.37, and the code looks stable enough to
keep that promise.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-11-10 12:00:47 -06:00
Christoph Hellwig bb8430a2c8 locks: remove fl_copy_lock lock_manager operation
This one was only used for a nasty hack in nfsd, which has recently
been removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-31 06:35:15 -07:00
Linus Torvalds f063a0c0c9 Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6: (841 commits)
  Staging: brcm80211: fix usage of roundup in structures
  Staging: bcm: fix up network device reference counting
  Staging: keucr: fix up US_ macro change
  staging: brcm80211: brcmfmac: Removed codeversion from firmware filenames.
  staging: brcm80211: Remove unnecessary header files.
  staging: brcm80211: Remove unnecessary includes from bcmutils.c
  staging: brcm80211: Removed unnecessary pktsetprio() function.
  Staging: brcm80211: remove typedefs.h
  Staging: brcm80211: remove uintptr typedef usage
  Staging: hv: remove struct vmbus_channel_interface
  Staging: hv: remove Open from struct vmbus_channel_interface
  Staging: hv: storvsc: call vmbus_open directly
  Staging: hv: netvsc: call vmbus_open directly
  Staging: hv: channel: export vmbus_open to modules
  Staging: hv: remove Close from struct vmbus_channel_interface
  Staging: hv: netvsc: call vmbus_close directly
  Staging: hv: storvsc: call vmbus_close directly
  Staging: hv: channel: export vmbus_close to modules
  Staging: hv: remove SendPacket from struct vmbus_channel_interface
  Staging: hv: storvsc: call vmbus_sendpacket directly
  ...

Fix up conflicts in
	drivers/staging/cx25821/cx25821-audio-upstream.c
	drivers/staging/cx25821/cx25821-audio.h
due to warring whitespace cleanups (neither of which were all that great)
2010-10-28 12:13:00 -07:00
Greg Kroah-Hartman e4c5bf8e3d Merge 'staging-next' to Linus's tree
This merges the staging-next tree to Linus's tree and resolves
some conflicts that were present due to changes in other trees that were
affected by files here.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-10-28 09:44:56 -07:00
Aneesh Kumar K.V 76381a42e4 fs/9p: Add access = client option to opt in acl evaluation.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2010-10-28 09:08:46 -05:00
Theodore Ts'o a107e5a3a4 Merge branch 'next' into upstream-merge
Conflicts:
	fs/ext4/inode.c
	fs/ext4/mballoc.c
	include/trace/events/ext4.h
2010-10-27 23:44:47 -04:00
Lukas Czerner bfff68738f ext4: add support for lazy inode table initialization
When the lazy_itable_init extended option is passed to mke2fs, it
considerably speeds up filesystem creation because inode tables are
not zeroed out.  The fact that parts of the inode table are
uninitialized is not a problem so long as the block group descriptors,
which contain information regarding how much of the inode table has
been initialized, has not been corrupted However, if the block group
checksums are not valid, e2fsck must scan the entire inode table, and
the the old, uninitialized data could potentially cause e2fsck to
report false problems.

Hence, it is important for the inode tables to be initialized as soon
as possble.  This commit adds this feature so that mke2fs can safely
use the lazy inode table initialization feature to speed up formatting
file systems.

This is done via a new new kernel thread called ext4lazyinit, which is
created on demand and destroyed, when it is no longer needed.  There
is only one thread for all ext4 filesystems in the system. When the
first filesystem with inititable mount option is mounted, ext4lazyinit
thread is created, then the filesystem can register its request in the
request list.

This thread then walks through the list of requests picking up
scheduled requests and invoking ext4_init_inode_table(). Next schedule
time for the request is computed by multiplying the time it took to
zero out last inode table with wait multiplier, which can be set with
the (init_itable=n) mount option (default is 10).  We are doing
this so we do not take the whole I/O bandwidth. When the thread is no
longer necessary (request list is empty) it frees the appropriate
structures and exits (and can be created later later by another
filesystem).

We do not disturb regular inode allocations in any way, it just do not
care whether the inode table is, or is not zeroed. But when zeroing, we
have to skip used inodes, obviously. Also we should prevent new inode
allocations from the group, while zeroing is on the way. For that we
take write alloc_sem lock in ext4_init_inode_table() and read alloc_sem
in the ext4_claim_inode, so when we are unlucky and allocator hits the
group which is currently being zeroed, it just has to wait.

This can be suppresed using the mount option no_init_itable.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2010-10-27 21:30:05 -04:00
Nikanth Karthikesan 03f890f8c2 /proc/pid/pagemap: document in Documentation/filesystems/proc.txt
Document /proc/pid/pagemap in Documentation/filesystems/proc.txt

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Cc: Richard Guenther <rguenther@suse.de>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:13 -07:00
Nikanth Karthikesan b40d4f84be /proc/pid/smaps: export amount of anonymous memory in a mapping
Export the number of anonymous pages in a mapping via smaps.

Even the private pages in a mapping backed by a file, would be marked as
anonymous, when they are modified. Export this information to user-space via
smaps.

Exporting this count will help gdb to make a better decision on which
areas need to be dumped in its coredump; and should be useful to others
studying the memory usage of a process.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:13 -07:00
Linus Torvalds 426e1f5cec Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (52 commits)
  split invalidate_inodes()
  fs: skip I_FREEING inodes in writeback_sb_inodes
  fs: fold invalidate_list into invalidate_inodes
  fs: do not drop inode_lock in dispose_list
  fs: inode split IO and LRU lists
  fs: switch bdev inode bdi's correctly
  fs: fix buffer invalidation in invalidate_list
  fsnotify: use dget_parent
  smbfs: use dget_parent
  exportfs: use dget_parent
  fs: use RCU read side protection in d_validate
  fs: clean up dentry lru modification
  fs: split __shrink_dcache_sb
  fs: improve DCACHE_REFERENCED usage
  fs: use percpu counter for nr_dentry and nr_dentry_unused
  fs: simplify __d_free
  fs: take dcache_lock inside __d_path
  fs: do not assign default i_ino in new_inode
  fs: introduce a per-cpu last_ino allocator
  new helper: ihold()
  ...
2010-10-26 17:58:44 -07:00
Linus Torvalds 18a043f941 Merge branch 'nfs-for-2.6.37' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
* 'nfs-for-2.6.37' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
  NFS: rename nfs.upcall -> nfs.idmap
  NFS: Fix a compile issue in nfs_root
2010-10-26 17:24:28 -07:00
Matt Mackall 0f4d208f19 Documentation/filesystems/proc.txt: improve smaps field documentation
Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Nikanth Karthikesan <knikanth@suse.de>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:05 -07:00
Bryan Schumaker eb1c86b8b5 NFS: rename nfs.upcall -> nfs.idmap
This patch renames the idmapper upcall program from nfs.upcall to nfs.idmap in
the NFS documentation.  This is because the program has been renamed in the
nfs-utils source.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2010-10-26 13:57:10 -04:00
Linus Torvalds a4dd8dce14 Merge branch 'nfs-for-2.6.37' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
* 'nfs-for-2.6.37' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
  net/sunrpc: Use static const char arrays
  nfs4: fix channel attribute sanity-checks
  NFSv4.1: Use more sensible names for 'initialize_mountpoint'
  NFSv4.1: pnfs: filelayout: add driver's LAYOUTGET and GETDEVICEINFO infrastructure
  NFSv4.1: pnfs: add LAYOUTGET and GETDEVICEINFO infrastructure
  NFS: client needs to maintain list of inodes with active layouts
  NFS: create and destroy inode's layout cache
  NFSv4.1: pnfs: filelayout: introduce minimal file layout driver
  NFSv4.1: pnfs: full mount/umount infrastructure
  NFS: set layout driver
  NFS: ask for layouttypes during v4 fsinfo call
  NFS: change stateid to be a union
  NFSv4.1: pnfsd, pnfs: protocol level pnfs constants
  SUNRPC: define xdr_decode_opaque_fixed
  NFSD: remove duplicate NFS4_STATEID_SIZE
2010-10-26 09:52:09 -07:00
Christoph Hellwig e1455d1bdc update block_device_operations documentation
Updated Documentation/filesystems/Locking to match the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2010-10-25 21:18:22 -04:00
Valerie Aurora d9d1dc802f Documentation: Fix trivial typo in filesystems/sharedsubtree.txt
Documentation: Fix trivial typo in filesystems/sharedsubtree.txt

This typo is easy to ignore unless you have spent a great deal of time
thinking about how to eliminate duplicate dentries in unions.

Signed-off-by: Valerie Aurora <vaurora@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25 21:18:21 -04:00
Linus Torvalds 74eb94b218 Merge branch 'nfs-for-2.6.37' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
* 'nfs-for-2.6.37' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (67 commits)
  SUNRPC: Cleanup duplicate assignment in rpcauth_refreshcred
  nfs: fix unchecked value
  Ask for time_delta during fsinfo probe
  Revalidate caches on lock
  SUNRPC: After calling xprt_release(), we must restart from call_reserve
  NFSv4: Fix up the 'dircount' hint in encode_readdir
  NFSv4: Clean up nfs4_decode_dirent
  NFSv4: nfs4_decode_dirent must clear entry->fattr->valid
  NFSv4: Fix a regression in decode_getfattr
  NFSv4: Fix up decode_attr_filehandle() to handle the case of empty fh pointer
  NFS: Ensure we check all allocation return values in new readdir code
  NFS: Readdir plus in v4
  NFS: introduce generic decode_getattr function
  NFS: check xdr_decode for errors
  NFS: nfs_readdir_filler catch all errors
  NFS: readdir with vmapped pages
  NFS: remove page size checking code
  NFS: decode_dirent should use an xdr_stream
  SUNRPC: Add a helper function xdr_inline_peek
  NFS: remove readdir plus limit
  ...
2010-10-25 13:48:29 -07:00
Fred Isaman 02c35fca7c NFSv4.1: pnfs: full mount/umount infrastructure
Allow a module implementing a layout type to register, and
have its mount/umount routines called for filesystems that
the server declares support it.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: Andy Adamson<andros@netapp.com>
Signed-off-by: Bian Naimeng <biannm@cn.fujitsu.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2010-10-24 18:07:10 -04:00