This fixes:

  =============================================
  [ INFO: possible recursive locking detected ]
  2.6.27-rc5-00283-g70bb0896 #68
  ---------------------------------------------
  touch/6855 is trying to acquire lock:
   (&info->bfs_lock){--..}, at: [<c02262f5>] bfs_delete_inode+0x9e/0x18c

  but task is already holding lock:
   (&info->bfs_lock){--..}, at: [<c0226c00>] bfs_create+0x45/0x187

  other info that might help us debug this:
  2 locks held by touch/6855:
   #0:  (&type->i_mutex_dir_key#5){--..}, at: [<c018ad13>] do_filp_open+0x10b/0x62f
   #1:  (&info->bfs_lock){--..}, at: [<c0226c00>] bfs_create+0x45/0x187

  stack backtrace:
  Pid: 6855, comm: touch Not tainted 2.6.27-rc5-00283-g70bb0896 #68
   [<c013e769>] validate_chain+0x458/0x9f4
   [<c013bece>] ? trace_hardirqs_off+0xb/0xd
   [<c013f36b>] __lock_acquire+0x666/0x6e0
   [<c013f440>] lock_acquire+0x5b/0x77
   [<c02262f5>] ? bfs_delete_inode+0x9e/0x18c
   [<c06aab74>] mutex_lock_nested+0xbc/0x234
   [<c02262f5>] ? bfs_delete_inode+0x9e/0x18c
   [<c02262f5>] ? bfs_delete_inode+0x9e/0x18c
   [<c02262f5>] bfs_delete_inode+0x9e/0x18c
   [<c0226257>] ? bfs_delete_inode+0x0/0x18c
   [<c01925e1>] generic_delete_inode+0x94/0xfe
   [<c019265d>] generic_drop_inode+0x12/0x12f
   [<c0191b7e>] iput+0x4b/0x4e
   [<c0226d1e>] bfs_create+0x163/0x187
   [<c0188b42>] vfs_create+0xa6/0x114
   [<c018adb5>] do_filp_open+0x1ad/0x62f
   [<c0107cdc>] ? native_sched_clock+0x82/0x96
   [<c06ac309>] ? _spin_unlock+0x27/0x3c
   [<c019379e>] ? alloc_fd+0xbf/0xc9
   [<c06ae2f4>] ? sub_preempt_count+0x9d/0xab
   [<c019379e>] ? alloc_fd+0xbf/0xc9
   [<c0180391>] do_sys_open+0x42/0xb8
   [<c041d564>] ? trace_hardirqs_on_thunk+0xc/0x10
   [<c0180449>] sys_open+0x1e/0x26
   [<c01038bd>] sysenter_do_call+0x12/0x31
   =======================

The problem is that we don't unlock the bfs->lock mutex before calling
iput (we do in the other cases).
Signed-off-by: NEric Sesterhenn <snakebyte@gmx.de>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace the BKL-based locking scheme used in the bfs driver by a private
filesystem-wide mutex.
Signed-off-by: NDmitri Vorobiev <dmitri.vorobiev@movial.fi>
Cc: Tigran Aivazian <tigran_aivazian@symantec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Stop the BFS filesystem from using iget() and read_inode().  Replace
bfs_read_inode() with bfs_iget(), and call that instead of iget().  bfs_iget()
then uses iget_locked() directly and returns a proper error code instead of an
inode in the event of an error.

bfs_fill_super() returns any error incurred when getting the root inode
instead of EINVAL.

[kamalesh@linux.vnet.ibm.com: build fix]
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I found a few bugs in the BFS driver.  Detailed description of the bugs as
well as the steps to reproduce the errors are given in the kernel bugzilla.
 Please follow these links for more information:

http://bugzilla.kernel.org/show_bug.cgi?id=9363
http://bugzilla.kernel.org/show_bug.cgi?id=9364
http://bugzilla.kernel.org/show_bug.cgi?id=9365
http://bugzilla.kernel.org/show_bug.cgi?id=9366

This patch fixes the bugs described above.  Besides, the patch introduces
coding style changes to make the BFS driver conform to the requirements
specified for Linux kernel code.  Finally, I made a few cosmetic changes
such as removal of trivial debug output.

Also, the patch removes the fields `si_lf_ioff' and `si_lf_sblk' of the
in-core superblock structure.  These fields are initialized but never
actually used.

If you are wondering why I need BFS, here is the answer: I am using this
driver in the context of Linux kernel classes I am teaching in the Moscow
State University and in the International Institute of Information
Technology in Pune, India.
Signed-off-by: NDmitri Vorobiev <dmitri.vorobiev@gmail.com>
Cc: Tigran Aivazian <tigran@veritas.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Many struct inode_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NJosef Sipek <jsipek@fsl.cs.sunysb.edu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is mostly included for parity with dec_nlink(), where we will have some
more hooks.  This one should stay pretty darn straightforward for now.
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When a filesystem decrements i_nlink to zero, it means that a write must be
performed in order to drop the inode from the filesystem.

We're shortly going to have keep filesystems from being remounted r/o between
the time that this i_nlink decrement and that write occurs.

So, add a little helper function to do the decrements.  We'll tie into it in a
bit to note when i_nlink hits zero.
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This eliminates the i_blksize field from struct inode.  Filesystems that want
to provide a per-inode st_blksize can do so by providing their own getattr
routine instead of using the generic_fillattr() function.

Note that some filesystems were providing pretty much random (and incorrect)
values for i_blksize.

[bunk@stusta.de: cleanup]
[akpm@osdl.org: generic_fillattr() fix]
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is a conversion to make the various file_operations structs in fs/
const.  Basically a regexp job, with a few manual fixups

The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)
Signed-off-by: NArjan van de Ven <arjan@infradead.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

* Makes BFS code endianness-clean.

* Fixes some signedness warnings.

* Fixes a problem in fs/bfs/inode.c:164 where inodes not synced to disk
  don't get fully marked as clean.  Here's how to reproduce it:

# mount -o loop -t bfs /bfs.img /mnt
# df -i /mnt
Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/bfs.img                  48       1      47    3% /mnt
# df -k /mnt
Filesystem           1K-blocks      Used Available Use% Mounted on
/bfs.img                   512         5       508   1% /mnt
# cp 60k-archive.zip /mnt/mt.zip
# df -k /mnt
Filesystem           1K-blocks      Used Available Use% Mounted on
/bfs.img                   512        65       447  13% /mnt
# df -i /mnt
Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/bfs.img                  48       2      46    5% /mnt
# rm /mnt/mt.zip
# echo $?
0

 [If the unlink happens before the buffers flush, the following happens:]

# df -i /mnt
Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/bfs.img                  48       2      46    5% /mnt
# df -k /mnt
Filesystem           1K-blocks      Used Available Use% Mounted on
/bfs.img                   512        65       447  13% /mnt

 fs/bfs/bfs.h           |    1
Signed-off-by: NAndrew Stribblehill <ads@wompom.org>
Cc: <tigran@veritas.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!