nilfs_remount() changes mount state of a superblock instance.  Even
though nilfs accesses other superblock instances during mount or
remount, the mount state was not properly protected in
nilfs_remount().

Moreover, nilfs_remount() has a lock order reversal problem;
nilfs_get_sb() holds:

  1. bdev->bd_mount_sem
  2. sb->s_umount  (sget acquires)

and nilfs_remount() holds:

  1. sb->s_umount  (locked by the caller in vfs)
  2. bdev->bd_mount_sem

To avoid these problems, this patch divides a semaphore protecting
super block instances from nilfs->ns_sem, and applies it to the mount
state protection in nilfs_remount().

With this change, bd_mount_sem use is removed from nilfs_remount() and
the lock order reversal will be resolved.  And the new rw-semaphore,
nilfs->ns_super_sem will properly protect the mount state except the
modification from nilfs_error function.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This simplifies the test function passed on the remaining sget()
callsite in nilfs.

Instead of checking mount type (i.e. ro-mount/rw-mount/snapshot mount)
in the test function passed to sget(), this patch first looks up the
nilfs_sb_info struct which the given mount type matches, and then
acquires the super block instance holding the nilfs_sb_info.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This stops using sget() for checking if an r/w-mount or an r/o-mount
exists on the device.  This elimination uses a back pointer to the
current mount added to nilfs object.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This will change the way to obtain nilfs object in nilfs_get_sb()
function.

Previously, a preliminary sget() call was performed, and the nilfs
object was acquired from a super block instance found by the sget()
call.

This patch, instead, instroduces a new dedicated function
find_or_create_nilfs(); as the name implies, the function finds an
existent nilfs object from a global list or creates a new one if no
object is found on the device.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The following EBUSY case in nilfs_get_sb() is meaningless.  Indeed,
this error code is never returned to the caller.

    if (!s->s_root) {
          ...
    } else if (!(s->s_flags & MS_RDONLY)) {
        err = -EBUSY;
    }

This simply removes the else case.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Now that all filesystems provide ->sync_fs methods we can change
__sync_filesystem to only call ->sync_fs.

This gives us a clear separation between periodic writeouts which
are driven by ->write_super and data integrity syncs that go
through ->sync_fs. (modulo file_fsync which is also going away)
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The call to ->write_super from __sync_filesystem will go away, so make
sure nilfs2 performs the same actions from inside ->sync_fs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The call to ->write_super from __sync_filesystem will go away, so make
sure jffs2 performs the same actions from inside ->sync_fs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Add a ->sync_fs method for data integrity syncs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Add a ->sync_fs method for data integrity syncs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al 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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Add a ->sync_fs method for data integrity syncs.  Factor out common code
between affs_put_super, affs_write_super and the new affs_sync_fs into
a helper.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

unfortunately, for affs (especially for affs directories) we have
no real way to keep track of metadata ownership.  So we have to
do more or less what file_fsync() does, but we do *not* need to
call write_super() there.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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

Missing conversion to host-endian before doing shifts
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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

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

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

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

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

* get minix_write_inode() to honour the second argument
* now we can use simple_fsync() for minixfs
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

kill ext2_sync_file() (along with ext2/fsync.c), get rid of
ext2_update_inode() - it's an alias of ext2_write_inode().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

* mark directory data blocks as assoc. metadata
* add new inode to deal with FAT, mark FAT blocks as assoc. metadata of that
* now ->fsync() is trivial both for files and directories
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs-internal parts of qnx4_fs.h taken to fs/qnx4/qnx4.h, includes adjusted,
qnx4_fs.h doesn't need unifdef anymore.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

* have directory operations use mark_buffer_dirty_inode(),
  so that sync_mapping_buffers() would get those.
* make qnx4_write_inode() honour its last argument.
* get rid of insane copies of very ancient "walk the indirect blocks"
  in qnx4/fsync - they never matched the actual fs layout and, fortunately,
  never'd been called.  Again, all this junk is not needed; ->fsync()
  should just do sync_mapping_buffers + sync_inode (and if we implement
  block allocation for qnx4, we'll need to use mark_buffer_dirty_inode()
  for extent blocks)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

writes associated buffers, then does sync_inode() to write
the inode itself (and to make it clean).  Depends on
->write_inode() honouring the second argument.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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

I think the block_dump output in __mark_inode_dirty is missing dentry locking.
Surely the i_dentry list can change any time, so we may not even *get* a
dentry there. If we do get one by chance, then it would appear to be able to
go away or get renamed at any time...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Some filesystems can call in to sync an inode that is still in the
I_NEW state (eg. ext family, when mounted with -osync). This is OK
because the filesystem has sole access to the new inode, so it can
modify i_state without races (because no other thread should be
modifying it, by definition of I_NEW). Ie. a false positive, so
remove the warnings.

The races are described here 7ef0d737,
which is also where the warnings were introduced.
Reported-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

the write_super method is used for

 (1) writing back the superblock periodically from pdflush
 (2) called just before ->sync_fs for data integerity syncs

We don't need (1) because we have our own peridoc writeout through xfssyncd,
and we don't need (2) because xfs_fs_sync_fs performs a proper synchronous
superblock writeout after all other data and metadata has been written out.

Also remove ->s_dirt tracking as it's only used to decide when too call
->write_super.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This should not trigger anymore, so kill it.
Acked-by: Anton Altaparmakov <aia21@cam.ac.uk>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The only user of the i_cindex element in the inode structure is used
is by the firewire drivers.  As part of an attempt to slim down the
inode structure to save memory --- since a typical Linux system will
have hundreds of thousands if not millions of inodes cached, a
reduction in the size inode has high leverage.

The firewire driver does not need i_cindex in any fast path, so it's
simple enough to calculate when it is needed, instead of wasting space
in the inode structure.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: krh@redhat.com
Cc: stefanr@s5r6.in-berlin.de
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Push down lock_super into ->write_super instances and remove it from the
caller.

Following filesystem don't need ->s_lock in ->write_super and are skipped:

 * bfs, nilfs2 - no other uses of s_lock and have internal locks in
	->write_super
 * ext2 - uses BKL in ext2_write_super and has internal calls without s_lock
 * reiserfs - no other uses of s_lock as has reiserfs_write_lock (BKL) in
 	->write_super
 * xfs - no other uses of s_lock and uses internal lock (buffer lock on
	superblock buffer) to serialize ->write_super.  Also xfs_fs_write_super
	is superflous and will go away in the next merge window
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>