Until now, we've used the same scheme as GFS1 for atime. This has failed
since atime is a per vfsmnt flag, not a per fs flag and as such the
"noatime" flag was not getting passed down to the filesystems. This
patch removes all the "special casing" around atime updates and we
simply use the VFS's atime code.

The net result is that GFS2 will now support all the same atime related
mount options of any other filesystem on a per-vfsmnt basis. We do lose
the "lazy atime" updates, but we gain "relatime". We could add lazy
atime to the VFS at a later date, if there is a requirement for that
variant still - I suspect relatime will be enough.

Also we lose about 100 lines of code after this patch has been applied,
and I have a suspicion that it will speed things up a bit, even when
atime is "on". So it seems like a nice clean up as well.

From a user perspective, everything stays the same except the loss of
the per-fs atime quantum tweekable (ought to be per-vfsmnt at the very
least, and to be honest I don't think anybody ever used it) and that a
number of options which were ignored before now work correctly.

Please let me know if you've got any comments. I'm pushing this out
early so that you can all see what my plans are.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

In case of error, the function gfs2_inode_lookup returns an
ERR pointer, but never returns a NULL pointer. So a NULL test that
necessarily comes after an IS_ERR test should be deleted, and a NULL
test that may come after a call to this function should be
strengthened by an IS_ERR test.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@match_bad_null_test@
expression x, E;
statement S1,S2;
@@
x = gfs2_inode_lookup(...)
... when != x = E
* if (x != NULL)
S1 else S2
// </smpl>
Signed-off-by: NJulien Brunel <brunel@diku.dk>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch fixes a locking issue in the rename code by ensuring that we hold
the per sb rename lock over both directory and "other" renames which involve
different parent directories.

At the same time, this moved the (only called from one place) function
gfs2_ok_to_move into the file that its called from, so we can mark it
static. This should make a code a bit easier to follow.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Peter Staubach <staubach@redhat.com>

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

The ability to mark files for direct i/o access when opened
normally is both unused and pointless, so this patch removes
support for that feature.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

GFS2 calls permission() to verify permissions after locks on the files
have been taken.

For this it's sufficient to call gfs2_permission() instead.  This
results in the following changes:

  - IS_RDONLY() check is not performed
  - IS_IMMUTABLE() check is not performed
  - devcgroup_inode_permission() is not called
  - security_inode_permission() is not called

IS_RDONLY() should be unnecessary anyway, as the per-mount read-only
flag should provide protection against read-only remounts during
operations.  do_gfs2_set_flags() has been fixed to perform
mnt_want_write()/mnt_drop_write() to protect against remounting
read-only.

IS_IMMUTABLE has been added to gfs2_permission()

Repeating the security checks seems to be pointless, as they don't
normally change, and if they do, it's independent of the filesystem
state.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch fixes a GFS2 filesystem consistency error reported from
function do_strip.  The problem was caused by a timing window
that allowed two vfs inodes to be created in memory that point
to the same file.  The problem is fixed by making the vfs's
iget_test, iget_set mechanism check and set a new bit in the
in-core gfs2_inode structure while the vfs inode spin_lock is held.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

There are several places where GFP_KERNEL allocations happen under a glock,
which will result in hangs if we're under memory pressure and go to re-enter the
fs in order to flush stuff out.  This patch changes the culprits to GFS_NOFS to
keep this problem from happening.  Thank you,
Signed-off-by: NJosef Bacik <jbacik@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

gfs2_alloc_get may fail so we have to check it to prevent
NULL pointer dereference.
Signed-off-by: NCyrill Gorcunov <gorcunov@gamil.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

a previous commit removed call to
init_special_inode from inode lookuping, this cause problems as:

 # mknod /mnt/gfs2/dev/null c 1 3
 # cat /mnt/gfs2/dev/null
 cat: /mnt/gfs2/dev/null: Invalid argument

without special inode, GFS2 cannot support char device file,
block device file, fifo pipe, and socket file, lose many important
features as a common file system.

this one line patch re add special inode support.
Signed-off-by: NDenis Cheng <crquan@gmail.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

struct inode_operations gfs2_dev_iops is always the same as gfs2_file_iops,
since Jan 2006, when GFS2 merged into mainstream kernel.

So one of them could be removed.
Signed-off-by: NDenis Cheng <crquan@gmail.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

We've previously been using a "try lock" in readpage on the basis that
it would prevent deadlocks due to the inverted lock ordering (our normal
lock ordering is glock first and then page lock). Unfortunately tests
have shown that this isn't enough. If the glock has a demote request
queued such that run_queue() in the glock code tries to do a demote when
its called under readpage then it will try and write out all the dirty
pages which requires locking them. This then deadlocks with the page
locked by readpage.

The solution is to always require two calls into readpage. The first
unlocks the page, gets the glock and returns AOP_TRUNCATED_PAGE, the
second does the actual readpage and unlocks the glock & page as
required.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The blocks counter is almost a duplicate of the i_blocks
field in the VFS inode. The only difference is that i_blocks
can be only 32bits long for 32bit arch without large single file
support. Since GFS2 doesn't handle the non-large single file
case (for 32 bit anyway) this adds a new config dependency on
64BIT || LSF. This has always been the case, however we've never
explicitly said so before.

Even if we do add support for the non-LSF case, we will still
not require this field to be duplicated since we will not be
able to access oversized files anyway.

So the net result of all this is that we shave 8 bytes from a gfs2_inode
and get our config deps correct.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

There were three fields being used to keep track of the location
of the most recently allocated block for each inode. These have
been merged into a single field in order to better keep the
data and metadata for an inode close on disk, and also to reduce
the space required for storage.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch forms a pair with the previous patch which shrunk
di_height. Like that patch di_depth is renamed i_depth and moved
into struct gfs2_inode directly. Also the field goes from 16 bits
to 8 bits since it is also limited to a max value which is rather
small (17 in this case). In addition we also now validate the field
against this maximum value when its read in.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

I noticed that the latest change to i_height got rid of the
value from the inode dump.  This patch adds it back.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch improves the calculation of the tree height in order to reduce
the number of operations which are carried out on each call to gfs2_block_map.
In the common case, we now make a single comparison, rather than calculating
the required tree height from scratch each time. Also in the case that the
tree does need some extra height, we start from the current height rather from
zero when we work out what the new height ought to be.

In addition the di_height field is moved into the inode proper and reduced
in size to a u8 since the value must be between 0 and GFS2_MAX_META_HEIGHT (10).
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Use iget_failed() in GFS2 to kill a failed inode.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I spotted this bug while I was digging around.  Looks like it could cause
a lockup in some rare error condition.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

It is possible to reduce the size of GFS2 inodes by taking the i_alloc
structure out of the gfs2_inode. This patch allocates the i_alloc
structure whenever its needed, and frees it afterward. This decreases
the amount of low memory we use at the expense of requiring a memory
allocation for each page or partial page that we write. A quick test
with postmark shows that the overhead is not measurable and I also note
that OCFS2 use the same approach.

In the future I'd like to solve the problem by shrinking down the size
of the members of the i_alloc structure, but for now, this reduces the
immediate problem of using too much low-memory on x86 and doesn't add
too much overhead.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

GFS2 supports two modes of locking - lock_nolock for single node filesystem
and lock_dlm for cluster mode locking. The gfs2 lock methods are removed from
file operation table for lock_nolock protocol. This would allow VFS to handle
posix lock and flock logics just like other in-tree filesystems without
duplication.
Signed-off-by: NS. Wendy Cheng <wcheng@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The only reason for adding glocks to the journal was to keep track
of which locks required a log flush prior to release. We add a
flag to the glock to allow this check to be made in a simpler way.

This reduces the size of a glock (by 12 bytes on i386, 24 on x86_64)
and means that we can avoid extra work during the journal flush.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Just like ext3 we now have three sets of address space operations
to cover the cases of writeback, ordered and journalled data
writes. This means that the individual operations can now become
less complicated as we are able to remove some of the tests for
file data mode from the code.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The i_cache was designed to keep references to the indirect blocks
used during block mapping so that they didn't have to be looked
up continually. The idea failed because there are too many places
where the i_cache needs to be freed, and this has in the past been
the cause of many bugs.

In addition there was no performance benefit being gained since the
disk blocks in question were cached anyway. So this patch removes
it in order to simplify the code to prepare for other changes which
would otherwise have had to add further support for this feature.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

As requested by Christoph, this patch cleans up GFS2's internal
read function so that it no longer uses the do_generic_mapping_read
function. This function is obsolete and GFS2 is the last user of it.

As a side effect the internal read code gets smaller and easier
to read and gfs2_readpage is split into two. One function has the locking
and the other function has the rest of the logic.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>

There is a possible deadlock between two processes on the same node, where one
process is deleting an inode, and another process is looking for allocated but
unused inodes to delete in order to create more space.

process A does an iput() on inode X, and it's i_count drops to 0. This causes
iput_final() to be called, which puts an inode into state I_FREEING at
generic_delete_inode(). There no point between when iput_final() is called, and
when I_FREEING is set where GFS2 could acquire any glocks. Once I_FREEING is
set, no other process on that node can successfully look up that inode until
the delete finishes.

process B locks the the resource group for the same inode in get_local_rgrp(),
which is called by gfs2_inplace_reserve_i()

process A tries to lock the resource group for the inode in
gfs2_dinode_dealloc(), but it's already locked by process B

process B waits in find_inode for the inode to have the I_FREEING state cleared.

Deadlock.

This patch solves the problem by adding an alternative to gfs2_iget(),
gfs2_iget_skip(), that simply skips any inodes that are in the I_FREEING
state.o The alternate test function is just like the original one, except that
it fails if the inode is being freed, and sets a skipped flag. The alternate
set function is just like the original, except that it fails if the skipped
flag is set. Only try_rgrp_unlink() calls gfs2_iget_skip() instead of
gfs2_iget().
Signed-off-by: NBenjamin E. Marzinski <bmarzins@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Fix a nasty inode meta data corruption issue by keeping the buffer head in
icache array. This buffer needs to stay in memory until journal flush occurs
Otherwise, gfs2_meta_inode_buffer could do a disk read before the inode hits
disk. It ends up with meta data corruptions. The buffer will be released as
part of the existing journal flush logic.
Signed-off-by: NS. Wendy Cheng <wcheng@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

GFS2 has been passing i_mode within NFS File Handle. Other than the
wrong assumption that there is always room for this extra 16 bit value,
the current gfs2_get_dentry doesn't really need the i_mode to work
correctly. Note that GFS2 NFS code does go thru the same lookup code
path as direct file access route (where the mode is obtained from name
lookup) but gfs2_get_dentry() is coded for different purpose. It is not
used during lookup time. It is part of the file access procedure call.
When the call is invoked, if on-disk inode is not in-memory, it has to
be read-in. This makes i_mode passing a useless overhead.
Signed-off-by: NS. Wendy Cheng <wcheng@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

GFS2 lookup code doesn't ask for inode shared glock. This implies during
in-memory inode creation for existing file, GFS2 will not disk-read in
the inode contents. This leaves no_formal_ino un-initialized during
lookup time. The un-initialized no_formal_ino is subsequently encoded
into file handle. Clients will get ESTALE error whenever it tries to
access these files.
Signed-off-by: NS. Wendy Cheng <wcheng@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

There were two issues during deallocation of unlinked inodes. The
first was relating to the use of a "try" lock which in the case of
the inode lock wasn't trying hard enough to deallocate in all
circumstances (now changed to a normal glock) and in the case of
the iopen lock didn't wait for the demotion of the shared lock before
attempting to get the exclusive lock, and thereby sometimes (timing dependent)
not completing the deallocation when it should have done.

The second issue related to the lack of a way to invalidate dcache entries
on remote nodes (now fixed by this patch) which meant that unlinks were
taking a long time to return disk space to the fs. By adding some code to
invalidate the dcache entries across the cluster for unlinked inodes, that
is now fixed.

This patch was written jointly by Abhijith Das and Steven Whitehouse.
Signed-off-by: NAbhijith Das <adas@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

fs/gfs2/inode.c: In function 'gfs2_lookupi':
fs/gfs2/inode.c:392: warning: 'error' may be used uninitialized in this function

Looks like a real bug to me.

Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Under certain circumstances its possible (though rather unlikely) that
inodes which were unlinked by one node while still open on another might
get "lost" in the sense that they don't get deallocated if the node
which held the inode open crashed before it was unlinked.

This patch adds the recovery code which allows automatic deallocation of
the inode if its found during block allocation (the sensible time to
look for such inodes since we are scanning the rgrp's bitmaps anyway at
this time, so it adds no overhead to do this).

Since the inode will have had its i_nlink set to zero, all we need to
trigger recovery is a lookup and an iput(), and the normal deallocation
code takes care of the rest.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This fixes a bug in the ordering of operations in the error path of
createi. Its not valid to do an iput() when holding the inode's glock
since the iput() will (in this case) result in delete_inode() being
called which needs to grab the lock itself. This was causing the
recursive lock checking code to trigger.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This adds a nanosecond timestamp feature to the GFS2 filesystem. Due
to the way that the on-disk format works, older filesystems will just
appear to have this field set to zero. When mounted by an older version
of GFS2, the filesystem will simply ignore the extra fields so that
it will again appear to have whole second resolution, so that its
trivially backward compatible.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch fixes some sign issues which were accidentally introduced
into the quota & statfs code during the endianess annotation process.
Also included is a general clean up which moves all of the _host
structures out of gfs2_ondisk.h (where they should not have been to
start with) and into the places where they are actually used (often only
one place). Also those _host structures which are not required any more
are removed entirely (which is the eventual plan for all of them).

The conversion routines from ondisk.c are also moved into the places
where they are actually used, which for almost every one, was just one
single place, so all those are now static functions. This also cleans up
the end of gfs2_ondisk.h which no longer needs the #ifdef __KERNEL__.

The net result is a reduction of about 100 lines of code, many functions
now marked static plus the bug fixes as mentioned above. For good
measure I ran the code through sparse after making these changes to
check that there are no warnings generated.

This fixes Red Hat bz #239686
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch cleans up the inode number handling code. The main difference
is that instead of looking up the inodes using a struct gfs2_inum_host
we now use just the no_addr member of this structure. The tests relating
to no_formal_ino can then be done by the calling code. This has
advantages in that we want to do different things in different code
paths if the no_formal_ino doesn't match. In the NFS patch we want to
return -ESTALE, but in the ->lookup() path, its a bug in the fs if the
no_formal_ino doesn't match and thus we can withdraw in this case.

In order to later fix bz #201012, we need to be able to look up an inode
without knowing no_formal_ino, as the only information that is known to
us is the on-disk location of the inode in question.

This patch will also help us to fix bz #236099 at a later date by
cleaning up a lot of the code in that area.

There are no user visible changes as a result of this patch and there
are no changes to the on-disk format either.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The following patch fixes Red Hat bz 229831. Without this patch its
possible for the wrong inode to be returned in certain cases. It is a
pretty unusual event, so that its taken some time to track down. Thanks
and due to Josef Whiter who did a lot of the testing required to thrack
this down and fix it.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

ok, the following is the minimum changes to get NFSD going before we
settle down this issue .. would appreciate this in the tree so other NFS
related works can get done in parallel.
Signed-off-by: NS. Wendy Cheng <wcheng@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Move the glock acquisition to outside of the transactions.

Lock odering must be preserved in order to prevent ABBA
deadlocks. The current gfs2_change_nlink code would tries
to grab the glock after having started a transaction and thus is holding
the log lock. This is inconsistent with other code paths in
gfs that grab the resource group glock prior to staring
a tranactions.

One problem with this fix is that the resource group
lock is always grabbed now even if the inode still has
ref count and can not be marked for unlink.
Signed-off-by: NRussell Cattelan <cattelan@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

In certain cases, its possible for NFS to call the lookup code while
holding the glock (when doing a readdirplus operation) so we need to
check for that and not try and lock the glock twice. This also fixes a
typo in a previous NFS related GFS2 patch.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>