nfsd: distinguish functions of NFSD_MAY_* flags

Most of the NFSD_MAY_* flags actually request permissions, but over the
years we've accreted a few that modify the behavior of the permission or
open

nfsd: distinguish functions of NFSD_MAY_* flags

Most of the NFSD_MAY_* flags actually request permissions, but over the
years we've accreted a few that modify the behavior of the permission or
open code in other ways.

Distinguish the two cases a little more. In particular, allow the
shortcut at the start of nfsd_permission to ignore the
non-permission-requesting bits.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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don't pass 'mounting_here' flag to follow_down()

it's always false now

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

NFSD, VFS: Remove dead code in nfsd_rename()

Currently we have the following code in fs/nfsd/vfs.c::nfsd_rename() :

...
host_err = nfsd_break_lease(odentry->d_inode);
if (host_err)
goto out_dr

NFSD, VFS: Remove dead code in nfsd_rename()

Currently we have the following code in fs/nfsd/vfs.c::nfsd_rename() :

...
host_err = nfsd_break_lease(odentry->d_inode);
if (host_err)
goto out_drop_write;
if (ndentry->d_inode) {
host_err = nfsd_break_lease(ndentry->d_inode);
if (host_err)
goto out_drop_write;
}
if (host_err)
goto out_drop_write;
...

'host_err' is guaranteed to be 0 by the time we test 'ndentry->d_inode'.
If 'host_err' becomes != 0 inside the 'if' statement, then we goto
'out_drop_write'. So, after the 'if' statement there is no way that
'host_err' can be anything but 0, so the test afterwards is just dead
code.
This patch removes the dead code.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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nfsd: break lease on unlink due to rename

4795bb37effb7b8fe77e2d2034545d062d3788a8 "nfsd: break lease on unlink,
link, and rename", only broke the lease on the file that was being
renamed, and didn'

nfsd: break lease on unlink due to rename

4795bb37effb7b8fe77e2d2034545d062d3788a8 "nfsd: break lease on unlink,
link, and rename", only broke the lease on the file that was being
renamed, and didn't handle the case where the target path refers to an
already-existing file that will be unlinked by a rename--in that case
the target file should have any leases broken as well.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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NFSD: memory corruption due to writing beyond the stat array

If nfsd fails to find an exported via NFS file in the readahead cache, it
should increment corresponding nfsdstats counter (ra_depth[10])

NFSD: memory corruption due to writing beyond the stat array

If nfsd fails to find an exported via NFS file in the readahead cache, it
should increment corresponding nfsdstats counter (ra_depth[10]), but due to a
bug it may instead write to ra_depth[11], corrupting the following field.

In a kernel with NFSDv4 compiled in the corruption takes the form of an
increment of a counter of the number of NFSv4 operation 0's received; since
there is no operation 0, this is harmless.

In a kernel with NFSDv4 disabled it corrupts whatever happens to be in the
memory beyond nfsdstats.

Signed-off-by: Konstantin Khorenko <khorenko@openvz.org>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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nfsd: don't leak dentry count on mnt_want_write failure

The exit cleanup isn't quite right here.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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

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>

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nfsd: break lease on unlink, link, and rename

Any change to any of the links pointing to an entry should also break
delegations.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

nfsd4: break lease on nfsd setattr

Leases (delegations) should really be broken on any metadata change, not
just on size change.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

nfsd: don't support msnfs export option

We've long had these pointless #ifdef MSNFS's sprinkled throughout the
code--pointless because MSNFS is always defined (and we give no config
option to make t

nfsd: don't support msnfs export option

We've long had these pointless #ifdef MSNFS's sprinkled throughout the
code--pointless because MSNFS is always defined (and we give no config
option to make that easy to change). So we could just remove the
ifdef's and compile the resulting code unconditionally.

But as long as we're there: why not just rip out this code entirely?
The only purpose is to implement the "msnfs" export option which turns
on Windows-like behavior in some cases, and:

- the export option isn't documented anywhere;
- the userland utilities (which would need to be able to parse
"msnfs" in an export file) don't support it;
- I don't know how to maintain this, as I don't know what the
proper behavior is; and
- google shows no evidence that anyone has ever used this.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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fs: dcache scale dentry refcount

Make d_count non-atomic and protect it with d_lock. This allows us to ensure a
0 refcount dentry remains 0 without dcache_lock. It is also fairly natural when
we sta

fs: dcache scale dentry refcount

Make d_count non-atomic and protect it with d_lock. This allows us to ensure a
0 refcount dentry remains 0 without dcache_lock. It is also fairly natural when
we start protecting many other dentry members with d_lock.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>

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nfsd4: move idmap and acl header files into fs/nfsd

These are internal nfsd interfaces.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

nfsd: remove some unnecessary dropit handling

We no longer need a few of these special cases.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Fix compile warnings due to missing removal of a 'ret' variable

Commit a8adbe3 forgot to remove the return variable, kill it.

drivers/block/loop.c: In function 'lo_splice_actor':
drivers/block/loop

Fix compile warnings due to missing removal of a 'ret' variable

Commit a8adbe3 forgot to remove the return variable, kill it.

drivers/block/loop.c: In function 'lo_splice_actor':
drivers/block/loop.c:398: warning: unused variable 'ret'
[...]
fs/nfsd/vfs.c: In function 'nfsd_splice_actor':
fs/nfsd/vfs.c:848: warning: unused variable 'ret'

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

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fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors

This patch pulls calls to buf->ops->confirm() from all actors passed
(also indirectly) to splice_from_pipe_feed().

Is avoiding the c

fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors

This patch pulls calls to buf->ops->confirm() from all actors passed
(also indirectly) to splice_from_pipe_feed().

Is avoiding the call to buf->ops->confirm() while splice()ing to
/dev/null is an intentional optimization? No other user does that
and this will remove this special case.

Against current linux.git 6313e3c21743cc88bb5bd8aa72948ee1e83937b6.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

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fs: add sync_inode_metadata

Add a new helper to write out the inode using the writeback code,
that is including the correct dirty bit and list manipulation. A few
of filesystems already opencode th

fs: add sync_inode_metadata

Add a new helper to write out the inode using the writeback code,
that is including the correct dirty bit and list manipulation. A few
of filesystems already opencode this, and a lot of others should be
using it instead of using write_inode_now which also writes out the
data.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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nfsd: fix NULL dereference in nfsd_statfs()

The commit ebabe9a9001af0af56c0c2780ca1576246e7a74b
pass a struct path to vfs_statfs
introduced the struct path initialization, and this seems to trig

nfsd: fix NULL dereference in nfsd_statfs()

The commit ebabe9a9001af0af56c0c2780ca1576246e7a74b
pass a struct path to vfs_statfs
introduced the struct path initialization, and this seems to trigger
an Oops on my machine.

fh_dentry field may be NULL and set later in fh_verify(), thus the
initialization of path must be after fh_verify().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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pass a struct path to vfs_statfs

We'll need the path to implement the flags field for statvfs support.
We do have it available in all callers except:

- ecryptfs_statfs. This one doesn't actually

pass a struct path to vfs_statfs

We'll need the path to implement the flags field for statvfs support.
We do have it available in all callers except:

- ecryptfs_statfs. This one doesn't actually need vfs_statfs but just
needs to do a caller to the lower filesystem statfs method.
- sys_ustat. Add a non-exported statfs_by_dentry helper for it which
doesn't won't be able to fill out the flags field later on.

In addition rename the helpers for statfs vs fstatfs to do_*statfs instead
of the misleading vfs prefix.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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nfsd: minor nfsd read api cleanup

Christoph points that the NFSv2/v3 callers know which case they want
here, so we may as well just call the file=NULL case directly instead of
making this conditiona

nfsd: minor nfsd read api cleanup

Christoph points that the NFSv2/v3 callers know which case they want
here, so we may as well just call the file=NULL case directly instead of
making this conditional.

Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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gcc-4.6: nfsd: fix initialized but not read warnings

Fixes at least one real minor bug: the nfs4 recovery dir sysctl
would not return its status properly.

Also I finished Al's 1e41568d7378d ("Take

gcc-4.6: nfsd: fix initialized but not read warnings

Fixes at least one real minor bug: the nfs4 recovery dir sysctl
would not return its status properly.

Also I finished Al's 1e41568d7378d ("Take ima_path_check() in nfsd
past dentry_open() in nfsd_open()") commit, it moved the IMA
code, but left the old path initializer in there.

The rest is just dead code removed I think, although I was not
fully sure about the "is_borc" stuff. Some more review
would be still good.

Found by gcc 4.6's new warnings.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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fsnotify: pass a file instead of an inode to open, read, and write

fanotify, the upcoming notification system actually needs a struct path so it can
do opens in the context of listeners, and it need

fsnotify: pass a file instead of an inode to open, read, and write

fanotify, the upcoming notification system actually needs a struct path so it can
do opens in the context of listeners, and it needs a file so it can get f_flags
from the original process. Close was the only operation that already was passing
a struct file to the notification hook. This patch passes a file for access,
modify, and open as well as they are easily available to these hooks.

Signed-off-by: Eric Paris <eparis@redhat.com>

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nfsd: bypass readahead cache when have struct file

The readahead cache compensates for the fact that the NFS server
currently does an open and close on every IO operation in the NFSv2 and
NFSv3 case

nfsd: bypass readahead cache when have struct file

The readahead cache compensates for the fact that the NFS server
currently does an open and close on every IO operation in the NFSv2 and
NFSv3 case.

In the NFSv4 case we have long-lived struct files associated with client
opens, so there's no need for this. In fact, concurrent IO's using
trying to modify the same file->f_ra may cause problems.

So, don't bother with the readahead cache in that case.

Note eventually we'll likely do this in the v2/v3 case as well by
keeping a cache of struct files instead of struct file_ra_state's.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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nfsd: remove unused assignment from nfsd_link

Trivial cleanup, since "dest" is never used.

Reported-by: Anshul Madan <Anshul.Madan@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

nfsd4: comment nitpick

Reported-by: "Madan, Anshul" <Anshul.Madan@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

nfsd: nfsd_setattr needs to call commit_metadata

The conversion of write_inode_now calls to commit_metadata in commit
f501912a35c02eadc55ca9396ece55fe36f785d0 missed out the call in nfsd_setattr.

B

nfsd: nfsd_setattr needs to call commit_metadata

The conversion of write_inode_now calls to commit_metadata in commit
f501912a35c02eadc55ca9396ece55fe36f785d0 missed out the call in nfsd_setattr.

But without this conversion we can't guarantee that a SETATTR request
has actually been commited to disk with XFS, which causes a regression
from 2.6.32 (only for NFSv2, but anyway).

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

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