Commit Graph

42 Commits

Author SHA1 Message Date
Ryusuke Konishi
e3154e9748 nilfs2: get rid of nilfs_sb_info structure
This directly uses sb->s_fs_info to keep a nilfs filesystem object and
fully removes the intermediate nilfs_sb_info structure.  With this
change, the hierarchy of on-memory structures of nilfs will be
simplified as follows:

Before:
  super_block
       -> nilfs_sb_info
             -> the_nilfs
                   -> cptree --+-> nilfs_root (current file system)
                               +-> nilfs_root (snapshot A)
                               +-> nilfs_root (snapshot B)
                               :
             -> nilfs_sc_info (log writer structure)
After:
  super_block
       -> the_nilfs
             -> cptree --+-> nilfs_root (current file system)
                         +-> nilfs_root (snapshot A)
                         +-> nilfs_root (snapshot B)
                         :
             -> nilfs_sc_info (log writer structure)

The reason why we didn't design so from the beginning is because the
initial shape also differed from the above.  The early hierachy was
composed of "per-mount-point" super_block -> nilfs_sb_info pairs and a
shared nilfs object.  On the kernel 2.6.37, it was changed to the
current shape in order to unify super block instances into one per
device, and this cleanup became applicable as the result.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2011-03-09 11:54:26 +09:00
Ryusuke Konishi
f7545144c2 nilfs2: use sb instance instead of nilfs_sb_info struct
This replaces sbi uses with direct reference to sb instance.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2011-03-09 11:05:08 +09:00
Ryusuke Konishi
be667377a8 nilfs2: record used amount of each checkpoint in checkpoint list
This records the number of used blocks per checkpoint in each
checkpoint entry of cpfile.  Even though userland tools can get the
block count via nilfs_get_cpinfo ioctl, it was not updated by the
nilfs2 kernel code.  This fixes the issue and makes it available for
userland tools to calculate used amount per checkpoint.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Jiro SEKIBA <jir@unicus.jp>
2011-03-08 14:58:31 +09:00
Ryusuke Konishi
828b1c50ae nilfs2: add compat ioctl
The current FS_IOC_GETFLAGS/SETFLAGS/GETVERSION will fail if
application is 32 bit and kernel is 64 bit.

This issue is avoidable by adding compat_ioctl method.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2011-03-08 14:58:30 +09:00
Ryusuke Konishi
b253a3e4f2 nilfs2: tighten restrictions on inode flags
Nilfs has few rectrictions on which flags may be set on which inodes
like ext2/3/4 filesystems used to be.  Specifically DIRSYNC may only
be set on directories and IMMUTABLE and APPEND may not be set on
links.  Tighten that to disallow TOPDIR being set on non-directories
and only NODUMP and NOATIME to be set on non-regular file,
non-directories.

This introduces a flags masking function like those of extN and uses
it during inode creation.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2011-03-08 14:58:29 +09:00
Ryusuke Konishi
365e215ce1 nilfs2: unfold nilfs_dat_inode function
nilfs_dat_inode function was a wrapper to switch between normal dat
inode and gcdat, a clone of the dat inode for garbage collection.

This function got obsolete when the gcdat inode was removed, and now
we can access the dat inode directly from a nilfs object.  So, we will
unfold the wrapper and remove it.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2011-01-10 14:38:39 +09:00
Ryusuke Konishi
bcbc8c648d nilfs2: do not pass sbi to functions which can get it from inode
This removes argument for passing nilfs_sb_info structure from
nilfs_set_file_dirty and nilfs_load_inode_block functions.  We can get
a pointer to the structure from inodes.

[Stephen Rothwell <sfr@canb.auug.org.au>: fix conflict with commit
 b74c79e993]

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2011-01-10 14:37:54 +09:00
Ryusuke Konishi
622daaff0a nilfs2: fiemap support
This adds fiemap to nilfs.  Two new functions, nilfs_fiemap and
nilfs_find_uncommitted_extent are added.

nilfs_fiemap() implements the fiemap inode operation, and
nilfs_find_uncommitted_extent() helps to get a range of data blocks
whose physical location has not been determined.

nilfs_fiemap() collects extent information by looping through
nilfs_bmap_lookup_contig and nilfs_find_uncommitted_extent routines.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2011-01-10 14:05:46 +09:00
Nick Piggin
b74c79e993 fs: provide rcu-walk aware permission i_ops
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:29 +11:00
Ryusuke Konishi
2879ed66e4 nilfs2: remove own inode allocator and destructor for metadata files
This finally removes own inode allocator and destructor functions for
metadata files.  Several routines, nilfs_mdt_new(),
nilfs_mdt_new_common(), nilfs_mdt_clear(), nilfs_mdt_destroy(), and
nilfs_alloc_inode_common() will be gone.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-10-23 09:24:39 +09:00
Ryusuke Konishi
032dbb3b50 nilfs2: see state of root dentry for mount check of snapshots
After applied the patch that unified sb instances, root dentry of
snapshots can be left in dcache even after their trees are unmounted.

The orphan root dentry/inode keeps a root object, and this causes
false positive of nilfs_checkpoint_is_mounted function.

This resolves the issue by having nilfs_checkpoint_is_mounted test
whether the root dentry is busy or not.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-10-23 09:24:38 +09:00
Ryusuke Konishi
f1e89c86fd nilfs2: use iget for all metadata files
This makes use of iget5_locked to allocate or get inode for metadata
files to stop using own inode allocator.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-10-23 09:24:38 +09:00
Ryusuke Konishi
c1c1d70920 nilfs2: get rid of GCDAT inode
This applies prepared rollback function and redirect function of
metadata file to DAT file, and eliminates GCDAT inode.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-10-23 09:24:38 +09:00
Ryusuke Konishi
dc3d3b810a nilfs2: deny write access to inodes in snapshots
Snapshots of nilfs are read-only.

After super block instances (sb) will be unified, nilfs will need to
check write access by a way other than implicit test with
IS_RDONLY(inode).  This is because IS_RDONLY() refers to MS_RDONLY bit
of inode->i_sb->s_flags and it will become inaccurate after the
unification of sb.

To prepare for the issue, this uses i_op->permission to deny write
access to inodes in snapshots.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-10-23 09:24:35 +09:00
Ryusuke Konishi
e912a5b668 nilfs2: use root object to get ifile
This rewrites functions using ifile so that they get ifile from
nilfs_root object, and will remove sbi->s_ifile.  Some functions that
don't know the root object are extended to receive it from caller.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-10-23 09:24:35 +09:00
Ryusuke Konishi
8e656fd518 nilfs2: make snapshots in checkpoint tree exportable
The previous export operations cannot handle multiple versions of
a filesystem if they belong to the same sb instance.

This adds a new type of file handle and extends export operations so
that they can get the inode specified by a checkpoint number as well
as an inode number and a generation number.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-10-23 09:24:34 +09:00
Ryusuke Konishi
4d8d9293dc nilfs2: set pointer to root object in inodes
This puts a pointer to nilfs_root object in the private part of
on-memory inode, and makes nilfs_iget function pick up the inode with
the same root object.

Non-root inodes inherit its nilfs_root object from parent inode.  That
of the root inode is allocated through nilfs_attach_checkpoint()
function.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-10-23 09:24:34 +09:00
Ryusuke Konishi
263d90cefc nilfs2: remove own inode hash used for GC
This uses inode hash function that vfs provides instead of the own
hash table for caching gc inodes.  This finally removes the own inode
hash from nilfs.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-10-23 09:24:34 +09:00
Linus Torvalds
5f248c9c25 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (96 commits)
  no need for list_for_each_entry_safe()/resetting with superblock list
  Fix sget() race with failing mount
  vfs: don't hold s_umount over close_bdev_exclusive() call
  sysv: do not mark superblock dirty on remount
  sysv: do not mark superblock dirty on mount
  btrfs: remove junk sb_dirt change
  BFS: clean up the superblock usage
  AFFS: wait for sb synchronization when needed
  AFFS: clean up dirty flag usage
  cifs: truncate fallout
  mbcache: fix shrinker function return value
  mbcache: Remove unused features
  add f_flags to struct statfs(64)
  pass a struct path to vfs_statfs
  update VFS documentation for method changes.
  All filesystems that need invalidate_inode_buffers() are doing that explicitly
  convert remaining ->clear_inode() to ->evict_inode()
  Make ->drop_inode() just return whether inode needs to be dropped
  fs/inode.c:clear_inode() is gone
  fs/inode.c:evict() doesn't care about delete vs. non-delete paths now
  ...

Fix up trivial conflicts in fs/nilfs2/super.c
2010-08-10 11:26:52 -07:00
Al Viro
6fd1e5c994 convert nilfs2 to ->evict_inode()
[folded build fix from sfr]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:48:25 -04:00
Ryusuke Konishi
c5ca48aabe nilfs2: reject incompatible filesystem
This forces nilfs to check compatibility of feature flags so as to
reject a filesystem with unknown features when it mounts or remounts
the filesystem.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-23 10:02:16 +09:00
Ryusuke Konishi
05d0e94b66 nilfs2: get rid of nilfs_bmap_union
This removes nilfs_bmap_union and finally unifies three structures and
the union in bmap/btree code into one.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-23 10:02:14 +09:00
Jiro SEKIBA
b2ac86e1a8 nilfs2: sync super blocks in turns
This will sync super blocks in turns instead of syncing duplicate
super blocks at the time.  This will help searching valid super root
when super block is written into disk before log is written, which is
happen when barrier-less block devices are unmounted uncleanly.  In
the situation, old super block likely points to valid log.

This patch introduces ns_sbwcount member to the nilfs object and adds
nilfs_sb_will_flip() function; ns_sbwcount counts how many times super
blocks write back to the disk.  And, nilfs_sb_will_flip() decides
whether flipping required or not based on the count of ns_sbwcount to
sync super blocks asymmetrically.

The following functions are also changed:

 - nilfs_prepare_super(): flips super blocks according to the
   argument.  The argument is calculated by nilfs_sb_will_flip()
   function.

 - nilfs_cleanup_super(): sets "clean" flag to both super blocks if
   they point to the same checkpoint.

To update both of super block information, caller of
nilfs_commit_super must set the information on both super blocks.

Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-23 10:02:11 +09:00
Jiro SEKIBA
d26493b6f0 nilfs2: introduce nilfs_prepare_super
This function checks validity of super block pointers.
If first super block is invalid, it will swap the super blocks.
The function should be called before any super block information updates.
Caller must obtain nilfs->ns_sem.

Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-23 10:02:10 +09:00
Ryusuke Konishi
60f46b7efc nilfs2: separate function that updates log position
This moves out section that updates information of the recent log
position stored in super blocks from nilfs_commit_super to a new
routine named nilfs_set_log_cursor.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-23 10:02:10 +09:00
Ryusuke Konishi
7ecaa46cfe nilfs2: add nilfs_cleanup_super
This function write out filesystem state to super blocks in order to
share the same cleanup work.  This is a preparation for making super
block writeback alternately.

Cc: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-23 10:02:10 +09:00
Christoph Hellwig
7ea8085910 drop unused dentry argument to ->fsync
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-27 22:05:02 -04:00
Al Viro
0319003d0d nilfs really shouldn't slap struct dentry on stack...
... especially when it only needs (and initializes) .d_name of it

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-03-03 14:07:58 -05:00
Alexey Dobriyan
828c09509b const: constify remaining file_operations
[akpm@linux-foundation.org: fix KVM]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-01 16:11:11 -07:00
Alexey Dobriyan
6e1d5dcc2b const: mark remaining inode_operations as const
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:24 -07:00
Alexey Dobriyan
7f09410bbc const: mark remaining address_space_operations const
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:24 -07:00
Al Viro
d441b1c293 switch nilfs2 to inode->i_acl
Actually, get rid of private analog, since nothing in there is
using ACLs at all so far.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-24 08:17:05 -04:00
Ryusuke Konishi
a53b4751ae nilfs2: use device's backing_dev_info for btree node caches
Previously, default_backing_dev_info was used for the mapping of btree
node caches.  This uses device dependent backing_dev_info to allow
detailed control of the device for the btree node pages.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-06-10 23:41:12 +09:00
Ryusuke Konishi
4f6b828837 nilfs2: fix lock order reversal in nilfs_clean_segments ioctl
This is a companion patch to ("nilfs2: fix possible circular locking
for get information ioctls").

This corrects lock order reversal between mm->mmap_sem and
nilfs->ns_segctor_sem in nilfs_clean_segments() which was detected by
lockdep check:

 =======================================================
 [ INFO: possible circular locking dependency detected ]
 2.6.30-rc3-nilfs-00003-g360bdc1 #7
 -------------------------------------------------------
 mmap/5294 is trying to acquire lock:
  (&nilfs->ns_segctor_sem){++++.+}, at: [<d0d0e846>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]

 but task is already holding lock:
  (&mm->mmap_sem){++++++}, at: [<c043700a>] do_page_fault+0x1d8/0x30a

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (&mm->mmap_sem){++++++}:
        [<c01470a5>] __lock_acquire+0x1066/0x13b0
        [<c01474a9>] lock_acquire+0xba/0xdd
        [<c01836bc>] might_fault+0x68/0x88
        [<c023c61d>] copy_from_user+0x2a/0x111
        [<d0d120d0>] nilfs_ioctl_prepare_clean_segments+0x1d/0xf1 [nilfs2]
        [<d0d0e2aa>] nilfs_clean_segments+0x6d/0x1b9 [nilfs2]
        [<d0d11f68>] nilfs_ioctl+0x2ad/0x318 [nilfs2]
        [<c01a3be7>] vfs_ioctl+0x22/0x69
        [<c01a408e>] do_vfs_ioctl+0x460/0x499
        [<c01a4107>] sys_ioctl+0x40/0x5a
        [<c01031a4>] sysenter_do_call+0x12/0x38
        [<ffffffff>] 0xffffffff

 -> #0 (&nilfs->ns_segctor_sem){++++.+}:
        [<c0146e0b>] __lock_acquire+0xdcc/0x13b0
        [<c01474a9>] lock_acquire+0xba/0xdd
        [<c0433f1d>] down_read+0x2a/0x3e
        [<d0d0e846>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]
        [<d0cfe0e5>] nilfs_page_mkwrite+0xe7/0x154 [nilfs2]
        [<c0183b0b>] __do_fault+0x165/0x376
        [<c01855cd>] handle_mm_fault+0x287/0x5d1
        [<c043712d>] do_page_fault+0x2fb/0x30a
        [<c0435462>] error_code+0x72/0x78
        [<ffffffff>] 0xffffffff

where nilfs_clean_segments() holds:

  nilfs->ns_segctor_sem -> copy_from_user()
                             --> page fault -> mm->mmap_sem

And, page fault path may hold:

  page fault -> mm->mmap_sem
         --> nilfs_page_mkwrite() -> nilfs->ns_segctor_sem

Even though nilfs_clean_segments() does not perform write access on
given user pages, it may cause deadlock because nilfs->ns_segctor_sem
is shared per device and mm->mmap_sem can be shared with other tasks.

To avoid this problem, this patch moves all calls of copy_from_user()
outside the nilfs->ns_segctor_sem lock in the ioctl.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-05-11 14:54:41 +09:00
Ryusuke Konishi
e7a7402c0d nilfs2: remove module version
A MODULE_VERSION() macro has been used in out-of-tree nilfs modules,
but it's needless and not updated in tree.  So, this removes it along
with the version declaration.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-04-13 09:53:50 +09:00
Ryusuke Konishi
612392307c nilfs2: support nanosecond timestamp
After a review of user's feedback for finding out other compatibility
issues, I found nilfs improperly initializes timestamps in inode;
CURRENT_TIME was used there instead of CURRENT_TIME_SEC even though nilfs
didn't have nanosecond timestamps on disk.  A few users gave us the report
that the tar program sometimes failed to expand symbolic links on nilfs,
and it turned out to be the cause.

Instead of applying the above displacement, I've decided to support
nanosecond timestamps on this occation.  Fortunetaly, a needless 64-bit
field was in the nilfs_inode struct, and I found it's available for this
purpose without impact for the users.

So, this will do the enhancement and resolve the tar problem.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:20 -07:00
Ryusuke Konishi
e339ad31f5 nilfs2: introduce secondary super block
The former versions didn't have extra super blocks.  This improves the
weak point by introducing another super block at unused region in tail of
the partition.

This doesn't break disk format compatibility; older versions just ingore
the secondary super block, and new versions just recover it if it doesn't
exist.  The partition created by an old mkfs may not have unused region,
but in that case, the secondary super block will not be added.

This doesn't make more redundant copies of the super block; it is a future
work.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:20 -07:00
Ryusuke Konishi
1f5abe7e7d nilfs2: replace BUG_ON and BUG calls triggerable from ioctl
Pekka Enberg advised me:
> It would be nice if BUG(), BUG_ON(), and panic() calls would be
> converted to proper error handling using WARN_ON() calls. The BUG()
> call in nilfs_cpfile_delete_checkpoints(), for example, looks to be
> triggerable from user-space via the ioctl() system call.

This will follow the comment and keep them to a minimum.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:19 -07:00
Ryusuke Konishi
7a9461939a nilfs2: use unlocked_ioctl
Pekka Enberg suggested converting ->ioctl operations to use
->unlocked_ioctl to avoid BKL.

The conversion was verified to be safe, so I will take it on this
occasion.

Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:19 -07:00
Ryusuke Konishi
8082d36aed nilfs2: remove compat ioctl code
This removes compat code from the nilfs ioctls and applies the same
function for both .ioctl and .compat_ioctl file operations.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:18 -07:00
Ryusuke Konishi
47420c7998 nilfs2: avoid double error caused by nilfs_transaction_end
Pekka Enberg pointed out that double error handlings found after
nilfs_transaction_end() can be avoided by separating abort operation:

 OK, I don't understand this. The only way nilfs_transaction_end() can
 fail is if we have NILFS_TI_SYNC set and we fail to construct the
 segment. But why do we want to construct a segment if we don't commit?

 I guess what I'm asking is why don't we have a separate
 nilfs_transaction_abort() function that can't fail for the erroneous
 case to avoid this double error value tracking thing?

This does the separation and renames nilfs_transaction_end() to
nilfs_transaction_commit() for clarification.

Since, some calls of these functions were used just for exclusion control
against the segment constructor, they are replaced with semaphore
operations.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:17 -07:00
Ryusuke Konishi
65b4643d3b nilfs2: add inode and other major structures
This adds the following common structures of the NILFS2 file system.

* nilfs_inode_info structure:
  gives on-memory inode.

* nilfs_sb_info structure:
  keeps per-mount state and a special inode for the ifile.
  This structure is attached to the super_block structure.

* the_nilfs structure:
  keeps shared state and locks among a read/write mount and snapshot
  mounts.  This keeps special inodes for the sufile, cpfile, dat, and
  another dat inode used during GC (gcdat).  This also has a hash table
  of dummy inodes to cache disk blocks during GC (gcinodes).

* nilfs_transaction_info structure:
  keeps per task state while nilfs is writing logs or doing indivisible
  inode or namespace operations.  This structure is used to identify
  context during log making and store nest level of the lock which
  ensures atomicity of file system operations.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:12 -07:00