Fix http://bugzilla.kernel.org/show_bug.cgi?id=4857

When pivot_root is called from an init script in an initramfs environment,
it causes a circular reference in the mount tree.

The cause of this is that pivot_root() is not prepared to handle pivoting
an unattached mount.  In an initramfs environment, rootfs is the root of
the namespace, and so it is not attached.

This patch fixes this and related problems, by returning -EINVAL if either
the current root or the new root is detached.
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Acked-by: NAl Viro <viro@parcelfarce.linux.theplanet.co.uk>
Cc: <bigfish@asmallpond.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

  attached patch should fix the following race:
     Proc 1                               Proc 2

     __flush_batch()
       ll_rw_block()
                                        do_get_write_access()
					   lock_buffer
                                             jh is only waiting for checkpoint
					     -> b_transaction == NULL ->
					     do nothing
                                           unlock_buffer
    test_set_buffer_locked()
    test_clear_buffer_dirty()
                                           __journal_file_buffer()
                                        change the data
    submit_bh()

and we have sent wrong data to disk...  We now clean the dirty buffer flag
under buffer lock in all cases and hence we know that whenever a buffer is
starting to be journaled we either finish the pending write-out before
attaching a buffer to a transaction or we won't write the buffer until the
transaction is going to be committed.

The test in jbd_unexpected_dirty_buffer() is redundant - remove it.
Furthermore we have to clear the buffer dirty bit under the buffer lock to
prevent races with buffer write-out (and hence prevent returning a buffer with
IO happening).
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use block layer predefined function.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We need to be sure that current data are sent to disk.  Hence we call
ll_rw_block() with SWRITE.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We need to be sure that current data in buffer are sent to disk.  Hence we
need to call ll_rw_block() with SWRITE.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We must be sure that the current data in buffer are sent to disk.  Hence we
have to call ll_rw_block() with SWRITE.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Introduce new ll_rw_block() operation SWRITE meaning that block layer should
wait for the buffer lock and write-out afterwards.  Hence data in buffers at
the time of call are guaranteed to be submitted to the disk.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix race between journal_commit_transaction() and other places as
journal_unmap_buffer() that are adding buffers to transaction's t_forget list.
 We have to protect against such places by holding j_list_lock even when
traversing the t_forget list.  The fact that other places can only add buffers
to the list makes the locking easier.  OTOH the lock ranking complicates the
stuff...
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

It seems that kjournald() may be missing a check of the JFS_UNMOUNT flag
before calling schedule().  This showed up in testing of OCFS2 recovery
where our recovery thread would hang in journal_kill_thread() called from
journal_destroy() because kjournald never got a chance to read the flag to
shut down before the schedule().

Zach pointed out the missing check which led me to hack up this trivial
patch.  It's been tested many times now and I have yet to reproduce the
hang, which was happening very regularly before.

<mild rant>
I'm guessing that we could really use some wait_event() calls with helper
functions in, well, most of jbd these days which would make a ton of the
wait code there vastly cleaner.
</mild rant>

As for why this doesn't happen in ext3 (or OCFS2 during normal
mount/unmount of the local nodes journal), I think it may that the specific
timing of events in the ocfs2 recovery thread exposes a race there.
Because ocfs2_replay_journal() is only interested in playing back the
journal, initialization and shutdown happen very quicky with no other
metadata put into that specific journal.
Acked-by: N"Stephen C. Tweedie" <sct@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This adds NLS support to HFS.  Using the kernel options iocharset and codepage
it's possible to map the disk encoding to a local mapping.  If these options
are not used, it falls back to the old direct mapping.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This adds support for show_options.  It also fixes some namespace polution in
the hfsplus driver.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This removes some old debug code, which is no longer needed.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch converts kcalloc(1, ...) calls to use the new kzalloc() function.
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

cifs_create() did totally the wrong thing with nd->intent.open.flags:
it interpreted nd->intent.open.flags as the original open flags, not
the one transformed for open_namei().  Also it used the intent data
even if it was not filled in (if called from sys_mknod()).
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

64 bit architectures all implement their own compatibility sys_open(),
when in fact the difference is simply not forcing the O_LARGEFILE
flag.  So use the a common function instead.
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Extract common code used by ptrace_attach() and may_ptrace_attach()
into a separate function.
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch fixes wrongly placed elements in the pid_directory_inos
enum.  Also add comment so this mistake is not repeated.
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch cleans up proc_cwd_link() and proc_root_link() by factoring
out common code into get_fs_struct().
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Extract common code into inline functions to make reading easier.
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove unused ia_attr_flags from struct iattr, and related defines.
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NCoywolf Qi Hunt <qiyong@fc-cn.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

People have run into a problem when they do this:

watch (file1, all_events);
watch (file2, some_events);

if file2 is a hard link to file1, some events will be missed because by
default we replace the mask.  The patch below adds a flag IN_MASK_ADD which
will cause inotify to add to the existing mask if present.
Signed-off-by: NJohn McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: NRobert Love <rml@novell.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The file `fs/umsdos/notes' contains only a small note about a possible bug
involving verify_area().  Since umsdos is no longer in the kernel and
verify_area() is also gone, it seems to make sense that this file goes the way
of the Dodo.

After applying this patch the `fs/umsdos/' directory will be empty and can be
removed entirely.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove a redundant fifo_poll() abstraction from fs/pipe.c and adds a big
fat comment stating we set POLLERR for FIFOs too on Linux unlike most
Unices.
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Mark variables which are usually accessed for reads with __readmostly.
Signed-off-by: NAlok N Kataria <alokk@calsoftinc.com>
Signed-off-by: NShai Fultheim <shai@scalex86.org>
Signed-off-by: NRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Every time cramfs_lookup() is called to lookup and inode for a dentry,
get_cramfs_inode() will allocate a new inode without checking to see if that
inode already exists in the inode cache.

This is fine the first time, but if the dentry cache entry(ies) associated
with that inode are aged out, but the inode entry is not aged out (which can
be quite common if the inode has buffer cache linked to it), cramfs_lookup()
will be called again and another inode will be allocated and added to the
inode cache creating a duplicate in the inode cache.

The big issue here is that the buffers associated with each inode cache entry
are not shared between the duplicates!

The older inode entries are now orphaned as no dentry points to it and won't
be freed until the buffer cache assoicated with them are first freed.  The
newest entry will have to create all new buffer cache for each part of its
file as the old buffer cache is now orphaned as well.

Patch below fixes this by making get_cramfs_inode() use the inode cache before
blindly creating a new entry every time.  This eliminates the duplicate inodes
and duplicate buffer cache.

Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

struct file cleanup: f_maxcount has an unique value (INT_MAX).  Just use
the hard-wired value.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

In update_atime(), timespec_equal() test is done twice in succession and
the second is always false.  This patch removes the second test.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch removes prototypes for the generic_file_open and
generic_file_llseek functions.

Besides being superfluous because they are already present in fs.h, they
were also wrong because the actual functions aren't weak functions.
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 patch contains the following updates to the help texts:
- QUOTA: most people will get the quota utilities from their
         distribution, and if not the mini-HOWTO will tell them
- QFMT_V2: quota utilities 3.01 are no longer recent, they are now
           ancient
           and 3.01 is lower than the minimal version documented in
           Documentation/Changes
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch fixes bug titled "sunrpc as module and bad proc/sys link count"
reported by Jiri Slaby.

The problem was, that only proc_dir_entry->nlink was updated and the
corresponding inode->i_nlink was not.  The fix is to implement the
inode->getattr() method, and update i_nlink (if necessary).

A quick audit of proc code shows that no other attribute changes after
creation.
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add fsnotify_xattr() hook to removexattr().
Signed-off-by: NRobert Love <rml@novell.com>
Signed-off-by: NJohn McCtuchan <ttb@tentacle.dhs.org>
Cc: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

      OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

This speeds up directory reads for large FAT partitions, if the buffercache
has to be filled from the drive. Following values were taken from:

        $ time find path_to_freshly_mounted_fat > /dev/null

on an otherwise idle system.

FAT with 16KB Clusters on IDE attached drive:   Factor  2
FAT with 32KB Clusters on USB2 attached drive:  Factor 10 (!)
Its less than 1/10 slower, if the buffercache is uptodate.

The patch introduces the new function fat_dir_readahead().

fat_dir_readahead() calls sb_breadahead() to readahead a whole cluster,
if the requested sector is the first one in a cluster.
It is usefull to do this, because on FAT directories occupy whole
clusters, with the exception of FAT12/FAT16 root dirs.

Readahead is only done, if the cluster's first sector is not uptodate
to avoid overhead, when the buffer cache is already uptodate.
Note that under memory pressure, the maximal byte count wasted
(read: has to be red from disk twice) is 1 cluster's size.  Thats 64KB.

fat_dir_readahead() is called from fat__get_entry().

There is also an unrelated cleanup at one spot:

        if (bh)
                brelse(bh);

is replaced with:

        brelse(bh);

brelse() can handle NULL pointer arguments by itself.
Signed-off-by: NKarsten Wiese <annabellesgarden@yahoo.de>
Signed-off-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When registering an RPC cache, cache_register() always sets the owner as the
sunrpc module.  However, there are RPC caches owned by other modules.  With
the incorrect owner setting, the real owning module can be removed potentially
with an open reference to the cache from userspace.

For example, if one were to stop the nfs server and unmount the nfsd
filesystem, the nfsd module could be removed eventhough rpc.idmapd had
references to the idtoname and nametoid caches (i.e.
/proc/net/rpc/nfs4.<cachename>/channel is still open).  This resulted in a
system panic on one of our machines when attempting to restart the nfs
services after reloading the nfsd module.

The following patch adds a 'struct module *owner' field in struct
cache_detail.  The owner is further assigned to the struct proc_dir_entry
in cache_register() so that the module cannot be unloaded while user-space
daemons have an open reference on the associated file under /proc.
Signed-off-by: NBruce Allan <bwa@us.ibm.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

If /etc/mtab is a regular file all of the mount options (of a file system)
are written to /etc/mtab by the mount command.  The quota tools look there
for the quota strings for their operation.  If, however, /etc/mtab is a
symlink to /proc/mounts (a "good thing" in some environments) the tools
don't write anything - they assume the kernel will take care of things.

While the quota options are sent down to the kernel via the mount system
call and the file system codes handle them properly unfortunately there is
no code to echo the quota strings into /proc/mounts and the quota tools
fail in the symlink case.

The attached patchs modify the EXT[2|3] and JFS codes to add the necessary
hooks.  The show_options function of each file system in these patches
currently deal with only those things that seemed related to quotas;
especially in the EXT3 case more can be done (later?).

Jan Kara also noted the difficulty in moving these changes above the FS
codes responding similarly to myself to Andrew's comment about possible
VFS migration. Issue summary:

 - FS codes have to process the entire string of options anyway.

 - Only FS codes that use quotas must have a show_options function (for
   quotas to work properly) however quotas are only used in a small number
   of FS.

 - Since most of the quota using FS support other options these FS codes
   should have the a show_options function to show those options - and the
   quota echoing becomes virtually negligible.

Based on feedback I have modified my patches from the original:

   JFS a missing patch has been restored to the posting
   EXT[2|3] and JFS always use the show_options function
       - Each FS has at least one FS specific option displayed
       - QUOTA output is under a CONFIG_QUOTA ifdef
       - a follow-on patch will add a multitude of options for each FS
   EXT[2|3] and JFS "quota" is treated as "usrquota"
   EXT3 journalled data check for journalled quota removed
   EXT[2|3] mount when quota specified but not compiled in

 - no changes from my original patch.  I tested the patch and the codes
   warn but

 - still mount.  With all due respection I believe the comments
   otherwise were a

 - misread of the patch.  Please reread/test and comment.  XFS patch
   removed - the XFS team already made the necessary changes EXT3 mixing
   old and new quotas are handled differently (not purely exclusive)

 - if old and new quotas for the same type are used together the old
   type is silently depricated for compatability (e.g.  usrquota and
   usrjquota)

 - mixing of old and new quotas is an error (e.g.  usrjquota and
   grpquota)
Signed-off-by: NMark Bellon <mbellon@mvista.com>
Acked-by: NDave Kleikamp <shaggy@austin.ibm.com>
Cc: Jan Kara <jack@ucw.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

All users have been converted.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Jens:

->bi_set is totally unnecessary bloat of struct bio.  Just define a proper
destructor for the bio and it already knows what bio_set it belongs too.

Peter:

Fixed the bugs.
Signed-off-by: NJens Axboe <axboe@suse.de>
Signed-off-by: NPeter Osterlund <petero2@telia.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch contains the following cleanups:
- make needlessly global functions static
- journal.c: remove the unused global function __journal_internal_check
             and move the check to journal_init
- remove the following write-only global variable:
  - journal.c: current_journal
- remove the following unneeded EXPORT_SYMBOL:
  - journal.c: journal_recover
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Acked-by: NAndreas Dilger <adilger@clusterfs.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When I first wrote the compat layer patches, I was somewhat cavalier about
the definition of compat_uid_t and compat_gid_t (or maybe I just
misunderstood :-)).  This patch makes the compat types much more consistent
with the types we are being compatible with and hopefully will fix a few
bugs along the way.

	compat type		type in compat arch
	__compat_[ug]id_t	__kernel_[ug]id_t
	__compat_[ug]id32_t	__kernel_[ug]id32_t
	compat_[ug]id_t		[ug]id_t

The difference is that compat_uid_t is always 32 bits (for the archs we
care about) but __compat_uid_t may be 16 bits on some.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Bypass an inotify-related fastpath spinlock and several function calls on
systems which have no inotify watches registered.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>