The patches that are intended to introduce copy-on-write credentials for 2.6.28
require abstraction of access to some fields of the task structure,
particularly for the case of one task accessing another's credentials where RCU
will have to be observed.

Introduced here are trivial no-op versions of the desired accessors for current
and other tasks so that other subsystems can start to be converted over more
easily.

Wrappers are introduced into a new header (linux/cred.h) for UID/GID,
EUID/EGID, SUID/SGID, FSUID/FSGID, cap_effective and current's subscribed
user_struct.  These wrappers are macros because the ordering between header
files mitigates against making them inline functions.

linux/cred.h is #included from linux/sched.h.

Further, XFS is modified such that it no longer defines and uses parameterised
versions of current_fs[ug]id(), thus getting rid of the namespace collision
otherwise incurred.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJames Morris <jmorris@namei.org>

In xfs_ialloc we just want to set all timestamps to the current time. We
don't need to mark the inode dirty like xfs_ichgtime does, and we don't
need nor want the opimizations in xfs_ichgtime that I will introduce in
the next patch.

So just opencode the timestamp update in xfs_ialloc, and remove the new
unused XFS_ICHGTIME_ACC case in xfs_ichgtime.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31825a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

All remaining bhv_vnode_t instance are in code that's more or less Linux
specific. (Well, for xfs_acl.c that could be argued, but that code is on
the removal list, too). So just do an s/bhv_vnode_t/struct inode/ over the
whole tree. We can clean up variable naming and some useless helpers
later.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31781a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

In various places we can just move a VFS_I call into the argument list of
called functions/macros instead of having a local bhv_vnode_t.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31776a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

When multiple inodes are locked in XFS it happens in order of the inode
number, with the everything but the first inode trylocked if any of the
previous inodes is in the AIL.

Except for the sorting of the inodes this logic is implemented in
xfs_lock_inodes, but also partially duplicated in xfs_lock_dir_and_entry
in a particularly stupid way adds a lock roundtrip if the inode ordering
is not optimal.

This patch adds a new helper xfs_lock_two_inodes that takes two inodes and
locks them in the most optimal way according to the above locking protocol
and uses it for all places that want to lock two inodes.

The only caller of xfs_lock_inodes is xfs_rename which might lock up to
four inodes.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31772a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NDonald Douwsma <donaldd@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

bhv_vnode_t is just a typedef for struct inode, so there's
no need for a helper to convert between the two.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31761a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Replace XFS_ITOV() with the new VFS_I() inline.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31724a
Signed-off-by: NDavid Chinner <david@fromorbit.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Replace XFS_ITOV_NULL() with the new VFS_I() inline.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31722a
Signed-off-by: NDavid Chinner <david@fromorbit.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

These days most of the attributes in struct inode are properly kept in
sync by XFS. This patch removes the need for vn_revalidate completely by:

- keeping inode.i_flags uptodate after any flags are updated in

xfs_ioctl_setattr

- keeping i_mode, i_uid and i_gid uptodate in xfs_setattr

SGI-PV: 984566

SGI-Modid: xfs-linux-melb:xfs-kern:31679a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NTim Shimmin <tes@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

it can be switched to take struct iattr directly and thus simplify the
implementation greatly. Also rename the ATTR_ flags to XFS_ATTR_ to not
conflict with the ATTR_ flags used by the VFS.

SGI-PV: 984565

SGI-Modid: xfs-linux-melb:xfs-kern:31678a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NTim Shimmin <tes@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

->setattr but also addition XFS-specific attributes: project id, inode
flags and extent size hint. Having these in a single function makes it
more complicated and forces to have us a bhv_vattr intermediate structure
eating up stackspace.

This patch adds a new xfs_ioctl_setattr helper for the XFS ioctls that set
these attributes and remove the code to set them through xfs_setattr.

SGI-PV: 984564

SGI-Modid: xfs-linux-melb:xfs-kern:31677a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NTim Shimmin <tes@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

xfs_remove and xfs_rmdir are almost the same with a little more work
performed in xfs_rmdir due to the . and .. entries. This patch merges
xfs_rmdir into xfs_remove and performs these actions conditionally.

Also clean up the error handling which was a nightmare in both versions
before.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31335a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NBarry Naujok <bnaujok@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

During a forced shutdown a xfs inode can be destroyed before log I/O
involving that inode is complete. We need to wait for the inode to be
unpinned before tearing it down. Version 2 cleans up the code a bit by
relying on xfs_iflush() to do the unpinning and forced shutdown check.

SGI-PV: 981240

SGI-Modid: xfs-linux-melb:xfs-kern:31326a
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
Signed-off-by: NDavid Chinner <dgc@sgi.com>

This implements the code to store the actual filename found during a
lookup in the dentry cache and to avoid multiple entries in the dcache
pointing to the same inode.

To avoid polluting the dcache, we implement a new directory inode
operations for lookup. xfs_vn_ci_lookup() stores the correct case name in
the dcache.

The "actual name" is only allocated and returned for a case- insensitive
match and not an actual match.

Another unusual interaction with the dcache is not storing negative
dentries like other filesystems doing a d_add(dentry, NULL) when an ENOENT
is returned. During the VFS lookup, if a dentry returned has no inode,
dput is called and ENOENT is returned. By not doing a d_add, this actually
removes it completely from the dcache to be reused. create/rename have to
be modified to support unhashed dentries being passed in.

SGI-PV: 981521
SGI-Modid: xfs-linux-melb:xfs-kern:31208a
Signed-off-by: NBarry Naujok <bnaujok@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>

xfs_igrow_start just expands to xfs_zero_eof with two asserts that are
useless in the context of the only caller and some rather confusing
comments.

xfs_igrow_finish is just a few lines of code decorated again with useless
asserts and confusing comments.

Just kill those two and merge them into xfs_setattr.

SGI-PV: 981498
SGI-Modid: xfs-linux-melb:xfs-kern:31186a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

xfs_fsync() fails to wait for data I/O completion before checking if the
inode is dirty or clean to decide whether to log the inode or not. This
misses inode size updates when the data flushed by the fsync() is
extending the file.

Hence, like fdatasync(), we need to wait for I/o completion first, then
check the inode for cleanliness. Doing so makes the behaviour of
xfs_fsync() identical for fsync and fdatasync and we *always* use
synchronous semantics if the inode is dirty. Therefore also kill the
differences and remove the unused flags from the xfs_fsync function and
callers.

SGI-PV: 981296
SGI-Modid: xfs-linux-melb:xfs-kern:31033a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

The VFS always has an inode reference when we call these functions. So we
only need to grab a signle reference to each inode that's joined to a
transaction - all the other bumping and dropping is as useless as the
comments describing the IRIX semantics.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30912a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

VFS guaranteed these can't happen.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30911a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

->rename already gets the target inode passed if it exits. Pass it down to
xfs_rename so that we can avoid looking it up again. Also simplify locking
as the first lock section in xfs_rename can go away now: the isdir is an
invariant over the lifetime of the inode, and new_parent and the nlink
check are namespace topology protected by i_mutex in the VFS. The projid
check needs to move into the second lock section anyway to not be racy.

Also kill the now unused xfs_dir_lookup_int and remove the now-unused
first_locked argumet to xfs_lock_inodes.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30903a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

The writer field is not needed for non_DEBU builds so remove it. While
we're at i also clean up the interface for is locked asserts to go through
and xfs_iget.c helper with an interface like the xfs_ilock routines to
isolated the XFS codebase from mrlock internals. That way we can kill
mrlock_t entirely once rw_semaphores grow an islocked facility. Also
remove unused flags to the ilock family of functions.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30902a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Opencode xfs-kill-xfs_dir_lookup_int here, which gets rid of a lock
roundtrip, and lots of stack space. Also kill the di_mode == 0 check that
has been done in xfs_iget for a few years now.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30901a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Similar to rmdir and remove - avoids a potential transaction reservation
overrun.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30900a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

It's currently used by the ACL code to read di_mode/di_uid, but these are
simple 32bit scalar values we can just read directly without locking.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30897a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

We can just check i_mode / di_mode directly.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30896a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

xfs_inactive() fails to report errors when committing the inactive
transaction. Hence we can get silent failures either finishing off the
truncation or committing the transaction. Even if we get errors, we need
to continue, so simply warn loudly to the system if we get errors here.

SGI-PV: 980084
SGI-Modid: xfs-linux-melb:xfs-kern:30830a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

xfsbdstrat() is declared to return an error. That is never checked because
the error is propagated by the xfs_buf_t that is passed through the
function.

Mark xfsbdstrat() as returning void and comment the prototype on the
methods needed for error checking.

SGI-PV: 980084
SGI-Modid: xfs-linux-melb:xfs-kern:30823a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30804a
Signed-off-by: NBarry Naujok <bnaujok@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

xfs_trans_commit() can return errors when there are problems in the
transaction subsystem. They are indicative that the entire transaction may
be incomplete, and hence the error should be propagated as there is a good
possibility that there is something fatally wrong in the filesystem. Catch
and propagate or warn about commit errors in the places where they are
currently ignored.

SGI-PV: 980084
SGI-Modid: xfs-linux-melb:xfs-kern:30795a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

This target component validation is not POSIX conformant and it is not
done by any other Linux filesystem so remove it from XFS.

SGI-PV: 980080
SGI-Modid: xfs-linux-melb:xfs-kern:30776a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30550a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30548a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30547a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30546a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30545a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

XFS changes the c/mtime of an inode when truncating it to the same size.
The c/mtime is only supposed to change if the size is changed. Not to be
confused with ftruncate, where the c/mtime is supposed to be changed even
if the size is not changed.

The Linux VFS encodes this semantic difference in the flags it sends down
to ->setattr, which XFS currently ignores. We need to make XFS pay
attention to the VFS flags and hence Do The Right Thing.

SGI-PV: 977547
SGI-Modid: xfs-linux-melb:xfs-kern:30536a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

We can just use xfs_ilock/xfs_iunlock instead and get rid of the ugly
bhv_vrwlock_t.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30533a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Instead of of xfs_get_dir_entry use a macro to get the xfs_inode from the
dentry in the callers and grab the reference manually.

Only grab the reference once as it's fine to keep it over the dmapi calls.
(And even that reference is actually superflous in Linux but I'll leave
that for another patch)

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30531a
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Remove open coded checks for the whether the inode is clean and replace
them with an inlined function.

SGI-PV: 977461
SGI-Modid: xfs-linux-melb:xfs-kern:30503a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

When pdflush is writing back inodes, it can get stuck on inode cluster
buffers that are currently under I/O. This occurs when we write data to
multiple inodes in the same inode cluster at the same time.

Effectively, delayed allocation marks the inode dirty during the data
writeback. Hence if the inode cluster was flushed during the writeback of
the first inode, the writeback of the second inode will block waiting for
the inode cluster write to complete before writing it again for the newly
dirtied inode.

Basically, we want to avoid this from happening so we don't block pdflush
and slow down all of writeback. Hence we introduce a non-blocking async
inode flush flag that pdflush uses. If this flag is set, we use
non-blocking operations (e.g. try locks) whereever we can to avoid
blocking or extra I/O being issued.

SGI-PV: 970925
SGI-Modid: xfs-linux-melb:xfs-kern:30501a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

SGI-PV: 971186
SGI-Modid: xfs-linux-melb:xfs-kern:30490a
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
Signed-off-by: NDonald Douwsma <donaldd@sgi.com>