Once a metadata block has been written, it must be recowed, so the
btrfs dirty balancing call has a check to make sure a fair amount of metadata
was actually dirty before it started writing it back to disk.

A previous commit had changed the dirty tracking for metadata without
updating the btrfs dirty balancing checks.  This commit switches it
to use the correct counter.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The block allocator in SSD mode will try to find groups of free blocks
that are close together.  This commit makes it loop less on a given
group size before bumping it.

The end result is that we are less likely to fill small holes in the
available free space, but we don't waste as much CPU building the
large cluster used by ssd mode.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

With the new back reference code, the cost of a balance has gone down
in terms of the number of back reference updates done.  This commit
makes us more aggressively balance leaves and nodes as they become
less full.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When the delayed reference code was added, some checks were added
to avoid extra balancing while the delayed references were being flushed.
This made for less efficient btrees, but it reduced the chances of
loops where no forward progress was made because the balances made
more delayed ref updates.

With the new dead root removal code and the mixed back references,
the extent allocation tree is no longer using precise back refs, and
the delayed reference updates don't carry the risk of looping forever
anymore.  So, the balance avoidance is no longer required.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.

When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one.  At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.

The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root.  This commit reduces the
transaction overhead by avoiding the need for dead root records.

When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.

This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.

We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.

This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.

This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.

This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.

The improved balancing code scales significantly better with a large
number of snapshots.

This is a very large commit and was written in a number of
pieces.  But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: NYan Zheng <zheng.yan@oracle.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

There are some 'start = state->end + 1;' like code in set_extent_bit
and clear_extent_bit. They overflow when end == (u64)-1.
Signed-off-by: NYan Zheng <zheng.yan@oracle.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

In commit code, we scan buffers attached to a transaction.  During this
scan, we sometimes have to drop j_list_lock and then we recheck whether
the journal buffer head didn't get freed by journal_try_to_free_buffers().
 But checking for buffer_jbd(bh) isn't enough because a new journal head
could get attached to our buffer head.  So add a check whether the journal
head remained the same and whether it's still at the same transaction and
list.

This is a nasty bug and can cause problems like memory corruption (use after
free) or trigger various assertions in JBD code (observed).
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: <stable@kernel.org>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The recent ->lookup() deadlock correction required the directory inode
mutex to be dropped while waiting for expire completion.  We were
concerned about side effects from this change and one has been identified.

I saw several error messages.

They cause autofs to become quite confused and don't really point to the
actual problem.

Things like:

handle_packet_missing_direct:1376: can't find map entry for (43,1827932)

which is usually totally fatal (although in this case it wouldn't be
except that I treat is as such because it normally is).

do_mount_direct: direct trigger not valid or already mounted
/test/nested/g3c/s1/ss1

which is recoverable, however if this problem is at play it can cause
autofs to become quite confused as to the dependencies in the mount tree
because mount triggers end up mounted multiple times.  It's hard to
accurately check for this over mounting case and automount shouldn't need
to if the kernel module is doing its job.

There was one other message, similar in consequence of this last one but I
can't locate a log example just now.

When checking if a mount has already completed prior to adding a new mount
request to the wait queue we check if the dentry is hashed and, if so, if
it is a mount point.  But, if a mount successfully completed while we
slept on the wait queue mutex the dentry must exist for the mount to have
completed so the test is not really needed.

Mounts can also be done on top of a global root dentry, so for the above
case, where a mount request completes and the wait queue entry has already
been removed, the hashed test returning false can cause an incorrect
callback to the daemon.  Also, d_mountpoint() is not sufficient to check
if a mount has completed for the multi-mount case when we don't have a
real mount at the base of the tree.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

CONFIG_IMA=y inode activity leaks iint_cache and radix_tree_node objects
until the system runs out of memory.  Nowhere is calling ima_inode_free()
a.k.a. ima_iint_delete().  Fix that by calling it from destroy_inode().
Signed-off-by: NHugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

OK, that's probably the easiest way to do that, as much as I don't like it...
Since iget() et.al. will not accept I_FREEING (will wait to go away
and restart), and since we'd better have serialization between new/free
on fs data structures anyway, we can afford simply skipping I_FREEING
et.al. in insert_inode_locked().

We do that from new_inode, so it won't race with free_inode in any interesting
ways and it won't race with iget (of any origin; nfsd or in case of fs
corruption a lookup) since both still will wait for I_LOCK.
Reviewed-by: N"Theodore Ts'o" <tytso@mit.edu>
Acked-by: NJan Kara <jack@suse.cz>
Tested-by: NDavid Watson <dbwatson@ukfsn.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The nobh_truncate_page() function is used by ext2, exofs, and jfs.  Of
these three, only ext2 and jfs's get_block() function pays attention
to bh->b_size --- which is normally always the filesystem blocksize
except when the get_block() function is called by either
mpage_readpage(), mpage_readpages(), or the direct I/O routines in
fs/direct_io.c.

Unfortunately, nobh_truncate_page() does not initialize map_bh before
calling the filesystem-supplied get_block() function.  So ext2 and jfs
will try to calculate the number of blocks to map by taking stack
garbage and shifting it left by inode->i_blkbits.  This should be
*mostly* harmless (except the filesystem will do some unnneeded work)
unless the stack garbage is less than filesystem's blocksize, in which
case maxblocks will be zero, and the attempt to find out whether or
not the filesystem has a hole at a given logical block will fail, and
the page cache entry might not get zero'ed out.

Also if the stack garbage in in map_bh->state happens to have the
BH_Mapped bit set, there could be an attempt to call readpage() on a
non-existent page, which could cause nobh_truncate_page() to return an
error when it should not.

Fix this by initializing map_bh->state and map_bh->size.

Fortunately, it's probably fairly unlikely that ext2 and jfs users
mount with nobh these days.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The btrfs allocator uses list_for_each to walk the available block
groups when searching for free blocks.  It starts off with a hint
to help find the best block group for a given allocation.

The hint is resolved into a block group, but we don't properly check
to make sure the block group we find isn't in the middle of being
freed due to filesystem shrinking or balancing.  If it is being
freed, the list pointers in it are bogus and can't be trusted.  But,
the code happily goes along and uses them in the list_for_each loop,
leading to all kinds of fun.

The fix used here is to check to make sure the block group we find really
is on the list before we use it.  list_del_init is used when removing
it from the list, so we can do a proper check.

The allocation clustering code has a similar bug where it will trust
the block group in the current free space cluster.  If our allocation
flags have changed (going from single spindle dup to raid1 for example)
because the drives in the FS have changed, we're not allowed to use
the old block group any more.

The fix used here is to check the current cluster against the
current allocation flags.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

It was not being properly initialized, and so the size saved to
disk was not correct.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

It's possible to recurse into filesystem from the memory
allocation, which deadlocks in xfs_qm_shake(). Add check
for __GFP_FS, and bail out if it is not set.
Signed-off-by: NFelix Blyakher <felixb@sgi.com>
Signed-off-by: NHedi Berriche <hedi@sgi.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NFelix Blyakher <felixb@sgi.com>

In the case where growing a filesystem would leave the last AG
too small, the fixup code has an overflow in the calculation
of the new size with one fewer ag, because "nagcount" is a 32
bit number.  If the new filesystem has > 2^32 blocks in it
this causes a problem resulting in an EINVAL return from growfs:

 # xfs_io -f -c "truncate 19998630180864" fsfile
 # mkfs.xfs -f -bsize=4096 -dagsize=76288719b,size=3905982455b fsfile
 # mount -o loop fsfile /mnt
 # xfs_growfs /mnt

meta-data=/dev/loop0             isize=256    agcount=52,
agsize=76288719 blks
         =                       sectsz=512   attr=2
data     =                       bsize=4096   blocks=3905982455, imaxpct=5
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal               bsize=4096   blocks=32768, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=0
realtime =none                   extsz=4096   blocks=0, rtextents=0
xfs_growfs: XFS_IOC_FSGROWFSDATA xfsctl failed: Invalid argument

Reported-by: richard.ems@cape-horn-eng.com
Signed-off-by: NEric Sandeen <sandeen@sandeen.net>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NFelix Blyakher <felixb@sgi.com>
Signed-off-by: NFelix Blyakher <felixb@sgi.com>

Regreesion from commit ef8f7fc5, which rearranged the code in
xfs_swap_extents() leading to double unlock of xfs inode ilock.
That resulted in xfs_fsr deadlocking itself on platforms, which
don't handle double unlock of rw_semaphore nicely. It caused the
count go negative, which represents the write holder, without
really having one. ia64 is one of the platforms where deadlock
was easily reproduced and the fix was tested.
Signed-off-by: NEric Sandeen <sandeen@sandeen.net>
Reviewed-by: NEric Sandeen <sandeen@sandeen.net>
Signed-off-by: NFelix Blyakher <felixb@sgi.com>

The nilfs_cpfile_delete_checkpoints() wrongly skips brelse() for the
header block of checkpoint file in case of errors.  This fixes the
leak bug.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

The flat loader uses an architecture's flat_stack_align() to align the
stack but assumes word-alignment is enough for the data sections.

However, on the Xtensa S6000 we have registers up to 128bit width
which can be used from userspace and therefor need userspace stack and
data-section alignment of at least this size.

This patch drops flat_stack_align() and uses the same alignment that
is required for slab caches, ARCH_SLAB_MINALIGN, or wordsize if it's
not defined by the architecture.

It also fixes m32r which was obviously kaput, aligning an
uninitialized stack entry instead of the stack pointer.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NOskar Schirmer <os@emlix.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Bryan Wu <cooloney@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: NJohannes Weiner <jw@emlix.com>
Acked-by: NMike Frysinger <vapier.adi@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

proc_pident_instantiate() has following call flow.

proc_pident_lookup()
  proc_pident_instantiate()
    proc_pid_make_inode()

And, proc_pident_lookup() has following error handling.

	const struct pid_entry *p, *last;
	error = ERR_PTR(-ENOENT);
	if (!task)
		goto out_no_task;

Then, proc_pident_instantiate should return ENOENT too when racing against
exit(2) occur.

EINAL has two bad reason.
  - it implies caller is wrong. bad the race isn't caller's mistake.
  - man 2 open don't explain EINVAL. user often don't handle it.

Note: Other proc_pid_make_inode() caller already use ENOENT properly.
Acked-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Erase errors such as:
"Newly-erased block contained word 0xa4ef223e at offset 0x0296a014"
and failure to write the clean marker,
moves the offending erase block to erasing list before calling
jffs2_erase_failed(). This is bad as jffs2_erase_failed() will
also move the block to the bad_list, but is now moving the
wrong block, causing FS corruption.
Signed-off-by: NJoakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

We don't need a kernel thread per CPU for this application.
Acked-by: NAlex Chiang <achiang@hp.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Commit 'Short write in nfsd becomes a full write to the client'
(31dec253) broken the sync write.
With the following commands to reproduce:

  $ mount -t nfs -o sync 192.168.0.21:/nfsroot /mnt
  $ cd /mnt
  $ echo aaaa > temp.txt

Then nfs client is hung up.

In SYNC mode the server alaways return the write count 0 to the
client. This is because the value of host_err in nfsd_vfs_write()
will be overwrite in SYNC mode by 'host_err=nfsd_sync(file);',
and then we return host_err(which is now 0) as write count.

This patch fixed the problem.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Fix up renamed filenames in comments in fs/cachefiles/internal.h.

Originally, the files were all called cf-xxx.c, but they got renamed to
just xxx.c.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix up renamed filenames in comments in fs/fscache/internal.h.

Originally, the files were all called fsc-xxx.c, but they got renamed to
just xxx.c.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the asynchronous lease renewal fails (usually due to a soft timeout),
then we _must_ schedule state recovery in order to ensure that we don't
lose the lease unnecessarily or, if the lease is already lost, that we
recover the locking state promptly...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fix build error with latest kbuild adjustments to initconst.

The commit a447c093 ("vfs: Use
const for kernel parser table") changed:

    static match_table_t __initdata tokens = {
to
    static match_table_t __initconst tokens = {

But the missing const causes popwerpc to fail with latest
updates to __initconst like this:

fs/nfs/nfsroot.c:400: error: __setup_str_nfs_root_setup causes a section type conflict
fs/nfs/nfsroot.c:400: error: __setup_str_nfs_root_setup causes a section type conflict

The bug is only present with kbuild-next.
Following patch has been build tested.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Small change (mostly formatting) to limit lookup based open calls to
file create only.

After discussion yesteday on samba-technical about the posix lookup
regression,  and looking at a problem with cifs posix open to one
particular Samba version, Jeff and JRA realized that Samba server's
behavior changed in this area (posix open behavior on files vs.
directories).   To make this behavior consistent, JRA just made a
fix to Samba server to alter how it handles open of directories (now
returning the equivalent of EISDIR instead of success). Since we don't
know at lookup time whether the inode is a directory or file (and
thus whether posix open will succeed with most current Samba server),
this change avoids the posix open code on lookup open (just issues
posix open on creates).    This gets the semantic benefits we want
(atomicity, posix byte range locks, improved write semantics on newly
created files) and file create still is fast, and we avoid the problem
that Jeff noticed yesterday with "openat" (and some open directory
calls) of non-cached directories to one version of Samba server, and
will work with future Samba versions (which include the fix jra just
pushed into Samba server).  I confirmed this approach with jra
yesterday and with Shirish today.

Posix open is only called (at lookup time) for file create now.
For opens (rather than creates), because we do not know if it
is a file or directory yet, and current Samba no longer allows
us to do posix open on dirs, we could end up wasting an open call
on what turns out to be a dir. For file opens, we wait to call posix
open till cifs_open.  It could be added here (lookup) in the future
but the performance tradeoff of the extra network request when EISDIR
or EACCES is returned would have to be weighed against the 50%
reduction in network traffic in the other paths.
Reviewed-by: NShirish Pargaonkar <shirishp@us.ibm.com>
Tested-by: NJeff Layton <jlayton@redhat.com>
CC: Jeremy Allison <jra@samba.org>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

This fixes a new memory leak problem in garbage collection.  The
problem was brought by the bugfix patch ("nilfs2: fix lock order
reversal in nilfs_clean_segments ioctl").

Thanks to Kentaro Suzuki for finding this problem.
Reported-by: NKentaro Suzuki <k_suzuki@ms.sylc.co.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Posix open code was not properly adding the file to the
list of open files.  Fix  allocating cifsFileInfo
more than once, and adding twice to flist and tlist.
Also fix mode setting to be done in one place in these
paths.
Signed-off-by: NSteve French <sfrench@us.ibm.com>
Reviewed-by: NShirish Pargaonkar <shirishp@us.ibm.com>
Tested-by: NJeff Layton <jlayton@redhat.com>
Tested-by: NLuca Tettamanti <kronos.it@gmail.com>

This is the third respin of the patch posted yesterday to fix the error
handling in cifs_follow_symlink. It also includes a fix for a bogus NULL
pointer check in CIFSSMBQueryUnixSymLink that Jeff Moyer spotted.

It's possible for CIFSSMBQueryUnixSymLink to return without setting
target_path to a valid pointer. If that happens then the current value
to which we're initializing this pointer could cause an oops when it's
kfree'd.

This patch is a little more comprehensive than the last patches. It
reorganizes cifs_follow_link a bit for (hopefully) better readability.
It should also eliminate the uneeded allocation of full_path on servers
without unix extensions (assuming they can get to this point anyway, of
which I'm not convinced).

On a side note, I'm not sure I agree with the logic of enabling this
query even when unix extensions are disabled on the client. It seems
like that should disable this as well. But, changing that is outside the
scope of this fix, so I've left it alone for now.
Reported-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@inraded.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

The problem is that permission checking is skipped if atomic open is
possible, but when exec opens a file, it just opens it O_READONLY which
means EXEC permission will not be checked at that time.

This problem is observed by the following sequence (executed as root):

  mount -t nfs4 server:/ /mnt4
  echo "ls" >/mnt4/foo
  chmod 744 /mnt4/foo
  su guest -c "mnt4/foo"
Signed-off-by: NFrank Filz <ffilzlnx@us.ibm.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
Tested-by: NEugene Teo <eugeneteo@kernel.sg>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds CONFIG_REISERFS_FS_XATTR protection from reiserfs_permission.

This is needed to avoid warnings during file deletions and chowns with
xattrs disabled.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This avoids an Oops in open_xa_root that can occur when deleting a file
with xattrs disabled.  It assumes that the xattr root will be there, and
that is not guaranteed.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With xattr cleanup even with xattrs disabled, much of the initial setup
is still performed.  Some #ifdefs are just not needed since the options
they protect wouldn't be available anyway.

This cleans those up.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

devpts_get_sb() calls memset(0) to clear mount options and calls
parse_mount_options() if user specified any mount options.

The memset(0) is bogus since the 'mode' and 'ptmxmode' options are
non-zero by default.  parse_mount_options() restores options to default
anyway and can properly deal with NULL mount options.

So in devpts_get_sb() remove memset(0) and call parse_mount_options() even
for NULL mount options.

Bug reported by Eric Paris: http://lkml.org/lkml/2009/5/7/448.
Signed-off-by: NSukadev Bhattiprolu <sukadev@us.ibm.com>
Tested-by: NMarc Dionne <marc.c.dionne@gmail.com>
Reported-by: NEric Paris <eparis@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Reviewed-by: N"H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If two CPU's simultaneously call ext4_ext_get_blocks() at the same
time, there is nothing protecting the i_cached_extent structure from
being used and updated at the same time.  This could potentially cause
the wrong location on disk to be read or written to, including
potentially causing the corruption of the block group descriptors
and/or inode table.

This bug has been in the ext4 code since almost the very beginning of
ext4's development.  Fortunately once the data is stored in the page
cache cache, ext4_get_blocks() doesn't need to be called, so trying to
replicate this problem to the point where we could identify its root
cause was *extremely* difficult.  Many thanks to Kevin Shanahan for
working over several months to be able to reproduce this easily so we
could finally nail down the cause of the corruption.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: N"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>

The BH_Unwritten flag indicates that the buffer is allocated on disk
but has not been written; that is, the disk was part of a persistent
preallocation area.  That flag should only be set when a get_blocks()
function is looking up a inode's logical to physical block mapping.

When ext4_get_blocks_wrap() is called with create=1, the uninitialized
extent is converted into an initialized one, so the BH_Unwritten flag
is no longer appropriate.  Hence, we need to make sure the
BH_Unwritten is not left set, since the combination of BH_Mapped and
BH_Unwritten is not allowed; among other things, it will result ext4's
get_block() to be called over and over again during the write_begin
phase of write(2).
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: NSankar P <sankar.curiosity@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The notreelog and flushoncommit mount options were being printed slightly
differently.
Signed-off-by: NSage Weil <sage@newdream.net>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

In Li Zefan's commit dae7b665,
a combination call of kmalloc() and copy_from_user() is replaced by
memdup_user(). So btrfs_ioctl_resize() doesn't use GFP_NOFS any more.
Signed-off-by: NLi Hong <lihong.hi@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>