At several places we modify EXT4_I(inode)->i_flags without holding
i_mutex (ext4_do_update_inode, ...). These modifications are racy and
we can lose updates to i_flags. So convert handling of i_flags to use
bitops which are atomic.

https://bugzilla.kernel.org/show_bug.cgi?id=15792Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

- Reorganize locking scheme to batch two atomic operation in to one.
  This also allow us to state what healthy group must obey following rule
  ext4_free_inodes_count(sb, gdp) == ext4_count_free(inode_bitmap, NUM);
- Fix possible undefined pointer dereference.
- Even if group descriptor stats aren't accessible we have to update
  inode bitmaps.
- Move non-group members update out of group_lock.
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

When used_dirs was introduced for the flex_groups struct, it looks
like the accounting was not put into place properly, in some places
manipulating free_inodes rather than used_dirs.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Get rid of the initialize dquot operation - it is now always called from
the filesystem and if a filesystem really needs it's own (which none
currently does) it can just call into it's own routine directly.

Rename the now static low-level dquot_initialize helper to __dquot_initialize
and vfs_dq_init to dquot_initialize to have a consistent namespace.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Get rid of the drop dquot operation - it is now always called from
the filesystem and if a filesystem really needs it's own (which none
currently does) it can just call into it's own routine directly.

Rename the now static low-level dquot_drop helper to __dquot_drop
and vfs_dq_drop to dquot_drop to have a consistent namespace.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Get rid of the alloc_inode and free_inode dquot operations - they are
always called from the filesystem and if a filesystem really needs
their own (which none currently does) it can just call into it's
own routine directly.

Also get rid of the vfs_dq_alloc/vfs_dq_free wrappers and always
call the lowlevel dquot_alloc_inode / dqout_free_inode routines
directly, which now lose the number argument which is always 1.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Calls to ext4_handle_dirty_metadata should only pass in an inode
pointer for inode-specific metadata, and not for shared metadata
blocks such as inode table blocks, block group descriptors, the
superblock, etc.

The BUG_ON can get tripped when updating a special device (such as a
block device) that is opened (so that i_mapping is set in
fs/block_dev.c) and the file system is mounted in no journal mode.

Addresses-Google-Bug: #2404870
Signed-off-by: NCurt Wohlgemuth <curtw@google.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Just a pet peeve of mine; we had a mishash of calls with either __func__
or "function_name" and the latter tends to get out of sync.

I think it's easier to just hide the __func__ in a macro, and it'll
be consistent from then on.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

At several places we modify EXT4_I(inode)->i_state without holding
i_mutex (ext4_release_file, ext4_bmap, ext4_journalled_writepage,
ext4_do_update_inode, ...). These modifications are racy and we can
lose updates to i_state. So convert handling of i_state to use bitops
which are atomic.

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

When compiling with EXT4FS_DEBUG on, gcc will complain with following warnings:

linux-2.6/fs/ext4/ialloc.c: In function ‘ext4_count_free_inodes’:
linux-2.6/fs/ext4/ialloc.c:1192: warning: format ‘%lu’ expects type
‘long unsigned int’, but argument 2 has type ‘ext4_group_t’

So add a type cast to suppress it. 
Signed-off-by: NPeng Tao <bergwolf@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Enhance the inode allocator to take a goal inode number as a
paremeter; if it is specified, it takes precedence over Orlov or
parent directory inode allocation algorithms.

The extents migration function uses the goal inode number so that the
extent trees allocated the migration function use the correct flex_bg.
In the future, the goal inode functionality will also be used to
allocate an adjacent inode for the extended attributes.

Also, for testing purposes the goal inode number can be specified via
/sys/fs/{dev}/inode_goal.  This can be useful for testing inode
allocation beyond 2^32 blocks on very large filesystems.
Signed-off-by: NAndreas Dilger <adilger@sun.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Instead of using a random number to determine the goal parent grop for
the Orlov top directories, use a hash of the directory name.  This
allows for repeatable results when trying to benchmark filesystem
layout algorithms.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The goal inode is specificed by inode number which belongs
to [1; s_inodes_count].
Signed-off-by: NJohann Lombardi <johann@sun.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If the caller isn't planning on modifying the block group descriptors,
there's no need to pass in a pointer to a struct buffer_head.  Nuking
this saves a tiny amount of CPU time and stack space usage.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

We have sb_bgl_lock() and ext4_group_info.bb_state
bit spinlock to protech group information. The later is only
used within mballoc code. Consolidate them to use sb_bgl_lock().
This makes the mballoc.c code much simpler and also avoid
confusion with two locks protecting same info.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Move the function prototypes in group.h into ext4.h so they are all
defined in one place.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Ext4's on-line resizing adds a new block group and then, only at the
last step adjusts s_groups_count.  However, it's possible on SMP
systems that another CPU could see the updated the s_group_count and
not see the newly initialized data structures for the just-added block
group.  For this reason, it's important to insert a SMP read barrier
after reading s_groups_count and before reading any (for example) the
new block group descriptors allowed by the increased value of
s_groups_count.

Unfortunately, we rather blatently violate this locking protocol
documented in fs/ext4/resize.c.  Fortunately, (1) on-line resizes
happen relatively rarely, and (2) it seems rare that the filesystem
code will immediately try to use just-added block group before any
memory ordering issues resolve themselves.  So apparently problems
here are relatively hard to hit, since ext3 has been vulnerable to the
same issue for years with no one apparently complaining.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If the Orlov allocator is having trouble finding an appropriate block
group, the fallback code could loop forever, causing a soft lockup
warning in find_group_orlov():

BUG: soft lockup - CPU#0 stuck for 61s! [cp:11728]
     ...
Pid: 11728, comm: cp Not tainted (2.6.30-rc1-dirty #77) Lenovo          
EIP: 0060:[<c021650e>] EFLAGS: 00000246 CPU: 0
EIP is at ext4_get_group_desc+0x54/0x9d
    ...
Call Trace:
 [<c0218021>] find_group_orlov+0x2ee/0x334
 [<c0120a5f>] ? sched_clock+0x8/0xb
 [<c02188e3>] ext4_new_inode+0x2cf/0xb1a
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Missing braces caused the warning to print more than once.
Signed-Off-By: NChuck Ebbert <cebbert@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Use lowercase names of quota functions instead of old uppercase ones.
Signed-off-by: NJan Kara <jack@suse.cz>
Acked-by: NMingming Cao <cmm@us.ibm.com>
CC: linux-ext4@vger.kernel.org

This is a short-term warning, and even printk_ratelimit() can result
in too much noise in system logs.  So only print it once as a warning.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Instead of looping over all of the block groups in a flex group
summing their summary statistics, start tracking used_dirs in struct
flex_groups, and use struct flex_groups instead.  This should save a
bit of CPU for mkdir-heavy workloads.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Reduce pressure on the sb_bgl_lock family of locks by using atomic_t's
to track the number of free blocks and inodes in each flex_group.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

I was seeing fsck errors on inode bitmaps after a 4 thread
dbench run on a 4 cpu machine:

Inode bitmap differences: -50736 -(50752--50753) etc...

I believe that this is because ext4_free_inode() uses atomic
bitops, and although ext4_new_inode() *used* to also use atomic 
bitops for synchronization, commit 
39341867 changed this to use
the sb_bgl_lock, so that we could also synchronize against
read_inode_bitmap and initialization of uninit inode tables.

However, that change left ext4_free_inode using atomic bitops,
which I think leaves no synchronization between setting & 
unsetting bits in the inode table.

The below patch fixes it for me, although I wonder if we're 
getting at all heavy-handed with this spinlock...
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The find_group_flex() inode allocator is now only used if the
filesystem is mounted using the "oldalloc" mount option.  It is
replaced with the original Orlov allocator that has been updated for
flex_bg filesystems (it should behave the same way if flex_bg is
disabled).  The inode allocator now functions by taking into account
each flex_bg group, instead of each block group, when deciding whether
or not it's time to allocate a new directory into a fresh flex_bg.

The block allocator has also been changed so that the first block
group in each flex_bg is preferred for use for storing directory
blocks.  This keeps directory blocks close together, which is good for
speeding up e2fsck since large directories are more likely to look
like this:

debugfs:  stat /home/tytso/Maildir/cur
Inode: 1844562   Type: directory    Mode:  0700   Flags: 0x81000
Generation: 1132745781    Version: 0x00000000:0000ad71
User: 15806   Group: 15806   Size: 1060864
File ACL: 0    Directory ACL: 0
Links: 2   Blockcount: 2072
Fragment:  Address: 0    Number: 0    Size: 0
 ctime: 0x499c0ff4:164961f4 -- Wed Feb 18 08:41:08 2009
 atime: 0x499c0ff4:00000000 -- Wed Feb 18 08:41:08 2009
 mtime: 0x49957f51:00000000 -- Fri Feb 13 09:10:25 2009
crtime: 0x499c0f57:00d51440 -- Wed Feb 18 08:38:31 2009
Size of extra inode fields: 28
BLOCKS:
(0):7348651, (1-258):7348654-7348911
TOTAL: 259
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This is a workaround for find_group_flex() which badly needs to be
replaced.  One of its problems (besides ignoring the Orlov algorithm)
is that it is a bit hyperactive about returning failure under
suspicious circumstances.  This can lead to spurious ENOSPC failures
even when there are inodes still available.

Work around this for now by retrying the search using
find_group_other() if find_group_flex() returns -1.  If
find_group_other() succeeds when find_group_flex() has failed, log a
warning message.

A better block/inode allocator that will fix this problem for real has
been queued up for the next merge window.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

At the moment there are few restrictions on which flags may be set on
which inodes.  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.

Introduces a flags masking function which masks flags based on mode and
use it during inode creation and when flags are set via the ioctl to
facilitate future consistency.
Signed-off-by: NDuane Griffin <duaneg@dghda.com>
Acked-by: NAndreas Dilger <adilger@sun.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

At present INDEX and EXTENTS are the only flags that new ext4 inodes do
NOT inherit from their parent.  In addition prevent the flags DIRTY,
ECOMPR, IMAGIC, TOPDIR, HUGE_FILE and EXT_MIGRATE from being inherited. 
List inheritable flags explicitly to prevent future flags from
accidentally being inherited.

This fixes the TOPDIR flag inheritance bug reported at
http://bugzilla.kernel.org/show_bug.cgi?id=9866.
Signed-off-by: NDuane Griffin <duaneg@dghda.com>
Acked-by: NAndreas Dilger <adilger@sun.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This mount option is largely superfluous, and in fact the way it was
implemented was buggy; if a filesystem which did not have the extents
feature flag was mounted -o extents, the filesystem would attempt to
create and use extents-based file even though the extents feature flag
was not eabled.  The simplest thing to do is to nuke the mount option
entirely.  It's not all that useful to force the non-creation of new
extent-based files if the filesystem can support it.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

We need to mark the block/inode bitmap beyond the end of the group
with '1'.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

For uninit block group, the on-disk bitmap is not initialized. That
implies we cannot depend on the uptodate flag on the bitmap
buffer_head to find bitmap validity.  Use a new buffer_head flag which
would be set after we properly initialize the bitmap.  This also
prevents (re-)initializing the uninit group bitmap every time we call 
ext4_read_block_bitmap().
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

We need to make sure we update the inode bitmap and clear
EXT4_BG_INODE_UNINIT flag with sb_bgl_lock held, since
ext4_read_inode_bitmap() looks at EXT4_BG_INODE_UNINIT to decide
whether to initialize the inode bitmap each time it is called.
(introduced by commit c806e68f.)

ext4_read_inode_bitmap does:

spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
	ext4_init_inode_bitmap(sb, bh, block_group, desc);

and ext4_new_inode does
if (!ext4_set_bit_atomic(sb_bgl_lock(sbi, group),
                   ino, inode_bitmap_bh->b_data))
		   ......
		   ...
spin_lock(sb_bgl_lock(sbi, group));

gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
i.e., on allocation we update the bitmap then we take the sb_bgl_lock
and clear the EXT4_BG_INODE_UNINIT flag. What can happen is a
parallel ext4_read_inode_bitmap can zero out the bitmap in between
the above ext4_set_bit_atomic and spin_lock(sb_bg_lock..)

The race results in below user visible errors
EXT4-fs error (device sdb1): ext4_free_inode: bit already cleared for inode 168449
EXT4-fs warning (device sdb1): ext4_unlink: Deleting nonexistent file ...
EXT4-fs warning (device sdb1): ext4_rmdir: empty directory has too many links ...
# ls -al /mnt/tmp/f/p369/d3/d6/d39/db2/dee/d10f/d3f/l71
ls: /mnt/tmp/f/p369/d3/d6/d39/db2/dee/d10f/d3f/l71: Stale NFS file handle
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

Rename some variables.  We also unlock locks in the reverse order we
acquired as a part of cleanup.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Rename the lower bits with suffix _lo and add helper
to access the values. Also rename bg_itable_unused_hi
to bg_pad as in e2fsprogs.
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: NAl Viro <viro@zeniv.linux.org.uk>

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NJames Morris <jmorris@namei.org>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: adilger@sun.com
Cc: linux-ext4@vger.kernel.org
Signed-off-by: NJames Morris <jmorris@namei.org>

When initializing an uninitialized block group in ext4_new_inode(),
its block group checksum must be re-calculated.  This fixes a race
when several threads try to allocate a new inode in an UNINIT'd group.

There is some question whether we need to be initializing the block
bitmap in ext4_new_inode() at all, but for now, if we are going to
init the block group, let's eliminate the race.
Signed-off-by: NFrederic Bohe <frederic.bohe@bull.net>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Nearly all places in the ext3/4 code which uses "unsigned long" is
probably a bug, since on 32-bit systems a ulong a 32-bits, which means
we are wasting stack space on 64-bit systems.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>