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: NNick Piggin <npiggin@kernel.dk>

Using %pV reduces the number of printk calls and
eliminates any possible message interleaving from
other printk calls.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NJan Kara <jack@suse.cz>

... and switch of the obvious get_sb_bdev() users to ->mount()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It's pointless - we *do* have busy inodes (root directory,
for one), so that call will fail and attempt to change
XIP flag will be ignored.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The BKL is still used in ext2_put_super(), ext2_fill_super(), ext2_sync_fs()
ext2_remount() and ext2_write_inode(). From these calls ext2_put_super(),
ext2_fill_super() and ext2_remount() are protected against each other by
the struct super_block s_umount rw semaphore. The call in ext2_write_inode()
could only protect the modification of the ext2_sb_info through
ext2_update_dynamic_rev() against concurrent ext2_sync_fs() or ext2_remount().
ext2_fill_super() and ext2_put_super() can be left out because you need a
valid filesystem reference in all three cases, which you do not have when
you are one of these functions.

If the BKL is only protecting the modification of the ext2_sb_info it can
safely be removed since this is protected by the struct ext2_sb_info s_lock.
Signed-off-by: NJan Blunck <jblunck@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

This patch is a preparation necessary to remove the BKL from do_new_mount().
It explicitly adds calls to lock_kernel()/unlock_kernel() around
get_sb/fill_super operations for filesystems that still uses the BKL.

I've read through all the code formerly covered by the BKL inside
do_kern_mount() and have satisfied myself that it doesn't need the BKL
any more.

do_kern_mount() is already called without the BKL when mounting the rootfs
and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
afs_mntpt_follow_link(). Both later functions are actually the filesystems
follow_link inode operation. vfs_kern_mount() is calling the specified
get_sb function and lets the filesystem do its job by calling the given
fill_super function.

Therefore I think it is safe to push down the BKL from the VFS to the
low-level filesystems get_sb/fill_super operation.

[arnd: do not add the BKL to those file systems that already
       don't use it elsewhere]
Signed-off-by: NJan Blunck <jblunck@infradead.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Christoph Hellwig <hch@infradead.org>

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

Follow the dquot_* style used elsewhere in dquot.c.

[Jan Kara: Fixed up missing conversion of ext2]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Only set the quota operation vectors if the filesystem actually supports
quota instead of doing it for all filesystems in alloc_super().

[Jan Kara: Export dquot_operations and vfs_quotactl_ops]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Currently the VFS calls into the quotactl interface for unmounting
filesystems.  This means filesystems with their own quota handling
can't easily distinguish between user-space originating quotaoff
and an unount.  Instead move the responsibily of the unmount handling
into the filesystem to be consistent with all other dquot handling.

Note that we do call dquot_disable a lot later now, e.g. after
a sync_filesystem.  But this is fine as the quota code does all its
writes via blockdev's mapping and that is synced even later.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Instead of having wrappers in the VFS namespace export the dquot_suspend
and dquot_resume helpers directly.  Also rename vfs_quota_disable to
dquot_disable while we're at it.

[Jan Kara: Moved dquot_suspend to quotaops.h and made it inline]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Currently do_remount_sb calls into the dquot code to tell it about going
from rw to ro and ro to rw.  Move this code into the filesystem to
not depend on the dquot code in the VFS - note ocfs2 already ignores
these calls and handles remount by itself.  This gets rid of overloading
the quotactl calls and allows to unify the VFS and XFS codepaths in
that area later.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

The BKL is still used in ext2_put_super(), ext2_fill_super(), ext2_sync_fs()
ext2_remount() and ext2_write_inode(). From these calls ext2_put_super(),
ext2_fill_super() and ext2_remount() are protected against each other by
the struct super_block s_umount rw semaphore. The call in ext2_write_inode()
could only protect the modification of the ext2_sb_info through
ext2_update_dynamic_rev() against concurrent ext2_sync_fs() or ext2_remount().
ext2_fill_super() and ext2_put_super() can be left out because you need a
valid filesystem reference in all three cases, which you do not have when
you are one of these functions.

If the BKL is only protecting the modification of the ext2_sb_info it can
safely be removed since this is protected by the struct ext2_sb_info s_lock.
Signed-off-by: NJan Blunck <jblunck@suse.de>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: NJan Kara <jack@suse.cz>

Add a spinlock that protects against concurrent modifications of
s_mount_state, s_blocks_last, s_overhead_last and the content of the
superblock's buffer pointed to by sbi->s_es. The spinlock is now used in
ext2_xattr_update_super_block() which was setting the
EXT2_FEATURE_COMPAT_EXT_ATTR flag on the superblock without protection
before. Likewise the spinlock is used in ext2_show_options() to have a
consistent view of the mount options.

This is a preparation patch for removing the BKL from ext2 in the next
patch.
Signed-off-by: NJan Blunck <jblunck@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jan Kara <jack@suse.cz>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NJan Kara <jack@suse.cz>

Move ext2_write_super() out of ext2_setup_super() as a preparation for the
next patch that adds a new lock for superblock fields.
Signed-off-by: NJan Blunck <jblunck@suse.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Both function originally did similar things except that ext2_sync_super()
is returning after the call to sync_dirty_buffer(sbh). Therefore this
patch adds a wait flag to tell ext2_sync_super() if it has to call
sync_dirty_buffer() to wait for in-progress I/O to finish.
Signed-off-by: NJan Blunck <jblunck@suse.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Depending in the state (valid or unchecked) of the filesystem either
ext2_sync_super() or ext2_commit_super() is called. If the filesystem is
currently valid (it is checked), we first mark it unchecked and afterwards
duplicate the work that ext2_sync_super() is doing later. Therefore this
patch removes the duplicate code and calls ext2_sync_super() directly after
marking the filesystem unchecked.
Signed-off-by: NJan Blunck <jblunck@suse.de>
Signed-off-by: NJan Kara <jack@suse.cz>

This is probably a typo since the write time should actually be updated by
ext2_sync_fs() instead of the mount time.
Signed-off-by: NJan Blunck <jblunck@suse.de>
Signed-off-by: NJan Kara <jack@suse.cz>

ext2_sync_fs() used to duplicate the code from ext2_clear_super_error().
Signed-off-by: NJan Blunck <jblunck@suse.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Get rid of the drop dquot operation - it is now always called from
the filesystem and if a filesystem really needs it's own (which none
currently does) it can just call into it's own routine directly.

Rename the now static low-level dquot_drop helper to __dquot_drop
and vfs_dq_drop to dquot_drop to have a consistent namespace.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Currently clear_inode calls vfs_dq_drop directly.  This means
we tie the quota code into the VFS.  Get rid of that and make the
filesystem responsible for the drop inside the ->clear_inode
superblock operation.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

This fixes a common warning reported by kerneloops.org

[Kernel summit hacking hour]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This fixes a WARN backtrace in mark_buffer_dirty() that occurs during
unmount when a USB or floppy device is removed. I reported this a kernel
regression, but looks like it might have been there for longer
than that.

The super block update from a previous operation has marked the buffer
as in error, and the flag has to be cleared before doing the update.
(Similar code already exists in ext4).
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NJan Kara <jack@suse.cz>

make messages produced by ext2 more unified. It should be
easy to parse.

dmesg before patch:
[ 4893.684892] reservations ON
[ 4893.684896] xip option not supported
[ 4893.684961] EXT2-fs warning: mounting ext3 filesystem as ext2
[ 4893.684964] EXT2-fs warning: maximal mount count reached, running
e2fsck is recommended
[ 4893.684990] EXT II FS: 0.5b, 95/08/09, bs=1024, fs=1024, gc=2,
bpg=8192, ipg=1280, mo=80010]

dmesg after patch:
[ 4893.684892] EXT2-fs (loop0): reservations ON
[ 4893.684896] EXT2-fs (loop0): xip option not supported
[ 4893.684961] EXT2-fs (loop0): warning: mounting ext3 filesystem as
ext2
[ 4893.684964] EXT2-fs (loop0): warning: maximal mount count reached,
running e2fsck is recommended
[ 4893.684990] EXT2-fs (loop0): 0.5b, 95/08/09, bs=1024, fs=1024, gc=2,
bpg=8192, ipg=1280, mo=80010]
Signed-off-by: NAlexey Fisher <bug-track@fisher-privat.net>
Reviewed-by: NAndreas Dilger <adilger@sun.com>
Signed-off-by: NJan Kara <jack@suse.cz>

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

Add a ->sync_fs method for data integrity syncs, and reimplement
->write_super ontop of it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

[xfs, btrfs, capifs, shmem don't need BKL, exempt]
Signed-off-by: NAlessio Igor Bogani <abogani@texware.it>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Move BKL into ->put_super from the only caller.  A couple of
filesystems had trivial enough ->put_super (only kfree and NULLing of
s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs,
hugetlbfs, omfs, qnx4, shmem, all others got the full treatment.  Most
of them probably don't need it, but I'd rather sort that out individually.
Preferably after all the other BKL pushdowns in that area.

[AV: original used to move lock_super() down as well; these changes are
removed since we don't do lock_super() at all in generic_shutdown_super()
now]
[AV: fuse, btrfs and xfs are known to need no damn BKL, exempt]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We just did a full fs writeout using sync_filesystem before, and if
that's not enough for the filesystem it can perform it's own writeout
in ->put_super, which many filesystems already do.

Move a call to foofs_write_super into every foofs_put_super for now to
guarantee identical behaviour until it's cleaned up by the individual
filesystem maintainers.

Exceptions:

 - affs already has identical copy & pasted code at the beginning of
   affs_put_super so no need to do it twice.
 - xfs does the right thing without it and I have changes pending for
   the xfs tree touching this are so I don't really need conflicts
   here..
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NManish Katiyar <mkatiyar@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The inode->i_mutex should be unlocked.

Found by smatch (http://repo.or.cz/w/smatch.git).  Compile tested.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>

ext2_quota_read() doesn't initialize tmp_bh.b_size before calling
ext2_get_block() where we access it. Since it is a local variable it
might contain some garbage. Make sure it is filled with reasonable
value before passing.
Signed-off-by: NManish Katiyar <mkatiyar@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>

For a reason that I was unable to understand in three months of debugging,
mount ext2 -o remount stopped working properly when remounting from
regular operation to xip, or the other way around.  According to a git
bisect search, the problem was introduced with the VM_MIXEDMAP/PTE_SPECIAL
rework in the vm:

commit 70688e4d
Author: Nick Piggin <npiggin@suse.de>
Date:   Mon Apr 28 02:13:02 2008 -0700

    xip: support non-struct page backed memory

In the failing scenario, the filesystem is mounted read only via root=
kernel parameter on s390x.  During remount (in rc.sysinit), the inodes of
the bash binary and its libraries are busy and cannot be invalidated (the
bash which is running rc.sysinit resides on subject filesystem).
Afterwards, another bash process (running ifup-eth) recurses into a
subshell, runs dup_mm (via fork).  Some of the mappings in this bash
process were created from inodes that could not be invalidated during
remount.

Both parent and child process crash some time later due to inconsistencies
in their address spaces.  The issue seems to be timing sensitive, various
attempts to recreate it have failed.

This patch refuses to change the xip flag during remount in case some
inodes cannot be invalidated.  This patch keeps users from running into
that issue.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: NCarsten Otte <cotte@de.ibm.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Jared Hulbert <jaredeh@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As spotted by kmemtrace, struct ext2_sb_info is 17024 bytes on 64-bit
which makes it a very bad fit for SLAB allocators.  The culprit of the
wasted memory is ->s_blockgroup_lock which can be as big as 16 KB when
NR_CPUS >= 32.

To fix that, allocate ->s_blockgroup_lock, which fits nicely in a order 2
page in the worst case, separately.  This shinks down struct ext2_sb_info
enough to fit a 1 KB slab cache so now we allocate 16 KB + 1 KB instead of
32 KB saving 15 KB of memory.
Acked-by: NAndreas Dilger <adilger@sun.com>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a much better version of a previous patch to make the parser
tables constant. Rather than changing the typedef, we put the "const" in
all the various places where its required, allowing the __initconst
exception for nfsroot which was the cause of the previous trouble.

This was posted for review some time ago and I believe its been in -mm
since then.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Alexander Viro <aviro@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Kmem cache passed to constructor is only needed for constructors that are
themselves multiplexeres.  Nobody uses this "feature", nor does anybody uses
passed kmem cache in non-trivial way, so pass only pointer to object.

Non-trivial places are:
	arch/powerpc/mm/init_64.c
	arch/powerpc/mm/hugetlbpage.c

This is flag day, yes.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Matt Mackall <mpm@selenic.com>
[akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c]
[akpm@linux-foundation.org: fix mm/slab.c]
[akpm@linux-foundation.org: fix ubifs]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move declarations of some macros, which should be in fact functions to
quotaops.h.  This way they can be later converted to inline functions
because we can now use declarations from quota.h.  Also add necessary
includes of quotaops.h to a few files.

[akpm@linux-foundation.org: fix JFS build]
[akpm@linux-foundation.org: fix UFS build]
[vegard.nossum@gmail.com: fix QUOTA=n build]
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Arjen Pool <arjenpool@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use ext2_group_first_block_no() and assign the return values to
ext2_fsblk_t variables.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert byte order of constant instead of variable which can be done at
compile time (vs run time).
Signed-off-by: NMarcin Slusarz <marcin.slusarz@gmail.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>